Aortic Regurgitation

AR may develop acutely or present as a chronic process, and results in diastolic blood flow reversal from the aorta to the left ventricle (LV). (Tsampasian, Echo Res Pract 2023)

Aortic regurgitation may result from abnormalities of the AV and the aortic root and may be acute or chronic. (Practical Perioperative TOE)

Acute aortic regurgitation (AR) differs from chronic AR in several important ways. The aetiology is often very different: infective endocarditis and aortic dissection are the most frequent causes of acute severe AR; less often it occurs as a complication of transcatheter procedures or blunt chest trauma. (BSE AR guideline 2025)

Because chronic AR progresses over many years, there is sufficient time for compensatory LV changes to develop. Acute severe AR allows no such compensation; consequently, LV filling pressures and left atrial pressures become significantly elevated. (BSE AR guideline 2025)

In acute regurgitation, the LV is classically not enlarged, whereas in chronic AR, LV dilation is likely. (Oxford Critical Care Echo)

Acute AR can be life threatening, as LV dilatation and other compensatory mechanisms cannot develop rapidly enough to avoid haemodynamic deterioration. (Maurer, Heart 2006)

Aortic regurgitation (AR) is the third most common valve lesion accounting for approximately 5% of adults undergoing intervention for severe valvular heart disease. (BSE AR guideline 2025)

The prevalence of AR in the Framingham study was reported to be 4.9%, with regurgitation of moderate or greater severity occurring in 0.5%. (Maurer, Heart 2006)

Aortic regurgitation (AR) is the result of aortic cusp abnormality, aortic root (AoR) dilatation, or a combination of the two. (BSE AR guideline 2025)

AR may be caused by malfunction of the valve leaflets themselves, by dilatation of the aortic root and annulus, or may be due to a combination of these factors. (Maurer, Heart 2006)

Common valvular abnormalities include senile leaflet calcifications, bicuspid aortic valve, rheumatic heart disease, and infective endocarditis. The mechanism of AR in the first two lesions occurs as a result of failure of the abnormal cusps to coapt. In rheumatic heart disease, regurgitation is a result of retraction and thickening of the cusps. (Oxford Critical Care Echo)

Aortic root causes of AR include idiopathic root dilatation, Marfan syndrome, syphilis, collagen vascular disease, and aortic dissection. Any condition that results in enlargement of the components of the aortic root (aortic annulus, sinuses of Valsalva, and sinotubular junction) will lead to the tethering of the aortic cusps, thus preventing its complete closure. (Oxford Critical Care Echo)

In Western countries, degenerative AV disease is the most common cause of AR, accounting for approximately half of the total cases. Rheumatic fever is the leading cause of AR in developing countries... alongside bicuspid aortic valve disease and infective endocarditis. (Tsampasian, Echo Res Pract 2023)

Degenerative AR is the most common aetiology in developed countries, accounting for approximately one-half of all cases of AR in the Euro Heart Survey on valvular heart disease. It is a heterogeneous entity that involves lesions of the leaflets (which are thin and subject to prolapse) and/or of aorta known as annuloaortic ectasia. (EACVI Textbook)

Rheumatic heart disease is the most common cause of AR in the developing world. Rheumatic fever is responsible for commissural fusion, thickening, and retraction of aortic leaflets, usually inducing central AR. (EACVI Textbook)

Indeed, aortic aneurysm alone may cause AR, even when the leaflets are normal, because changes in the geometry of the aortic root modify the geometry of the aortic valve and create abnormal stress on leaflet implantation. (EACVI Textbook)

Aetiologies of acute AR include infective endocarditis, aortic dissection, and traumatic rupture of the valve leaflets. Endocarditis accounts for approximately 10% of all cases of AR. (EACVI Textbook)

AR results from disease of either the aortic leaflets or the aortic root that distorts the leaflets and prevents their correct apposition. Common causes of leaflet abnormalities... include senile leaflet calcifications, bicuspid aortic valve, infective endocarditis, and rheumatic fever. Aortic causes of AR include annulo-aortic ectasia (idiopathic root dilatation), Marfan's syndrome, aortic dissection, collagen vascular disease, and syphilis. (EACVI valvular regurgitation recs)

Bicuspid aortic valves (BAV) are the most common anatomical variant, with a prevalence of approximately 1%, and a familial preponderance. BAV are commonly associated with AoR and AscAo dilatation, premature valve dysfunction, and increased risk of aortic dissection. (BSE AR guideline 2025)

This guideline recommends that BAV should not be described by 'type'. Instead, BAV should be reported descriptively by valve orientation (anterior-posterior vs left-right), noting fusion of the cusps, presence or absence of a raphe, and the number and symmetry of the sinuses. (BSE AR guideline 2025)

Bicuspid aortic valve is a frequent aetiology of AR, which should be strongly suspected whenever markedly eccentric leaflet coaptation is seen on parasternal views. (EACVI Textbook)

In bicuspid AR, the long-axis view may reveal an asymmetric closure line, systolic doming, or diastolic prolapse of the leaflets. The short-axis view is more specific. The diagnosis is confirmed when only two leaflets are seen in systole with two commissures framing an elliptical systolic orifice. (EACVI Textbook)

An aneurysm predominantly situated above the sinus of Valsalva, at the level of the tubular aorta, is often associated with a bicuspid aortic valve, and intrinsic disease of the media also appears to be responsible for aortic enlargement beyond that predicted by haemodynamic factors. (EACVI Textbook)

A dilated ascending aorta is frequently seen to co-exist in patients with bicuspid AV and connective tissue disorders. (Tsampasian, Echo Res Pract 2023)

Since it assumes a circular regurgitant orifice, if the orifice shape is irregular, as in bicuspid valve, the colour jet width is less related to the degree of regurgitation. (EACVI valvular regurgitation recs)

In the context of chronic AR, the left ventricle (LV) is exposed to increased preload, leading to adaptive changes including progressive dilatation and eccentric left ventricular hypertrophy (LVH). A normal indexed LV volume in and of itself therefore almost always rules out severe AR, except in rare circumstances including acute AR. (BSE AR guideline 2025)

As AR progresses, LV dilatation eventually becomes maladaptive, at which point LV function will become impaired, patients may develop symptoms, and prognosis is compromised. (BSE AR guideline 2025)

Chronic AR results in volume and pressure overload. The left ventricle adapts by progressive dilatation and hypertrophy. In compensated chronic AR, this adaptation is effective to maintain normal peripheral haemodynamics. (EACVI Textbook)

In the long term, these mechanisms of adaptation are no longer able to cope, resulting in the stage of decompensated AR characterized by systolic LV dysfunction. (EACVI Textbook)

AR causes volume overload of the left ventricle (LV). The total stroke volume ejected by the LV (sum of effective stroke volume plus regurgitant volume) is increased; in severe AR regurgitant volume may equal or even exceed effective stroke volume. (Maurer, Heart 2006)

An increase in LV end-diastolic volume is the main compensatory mechanism needed to maintain a normal effective stroke volume. Left ventricular ejection fraction is initially normal, however, LV end-diastolic pressure rises. (Maurer, Heart 2006)

In acute AR, the abrupt increase in backward blood flow into a normal size LV results in a marked elevation in end-diastolic pressure relative to the regurgitant volume. (Oxford Critical Care Echo)

Long-standing volume overload results in LV remodelling, which ultimately results in maladaptive changes to the myocardium, decline of LV function and the development of symptoms. (Tsampasian, Echo Res Pract 2023)

In acute AR, the LV is classically not enlarged, while in the chronic situation, the LV progressively dilates and irreversible LV damage may occur. (EACVI valvular regurgitation recs)

Work through it in a logical order: define the valve and the mechanism of regurgitation, build severity from qualitative to quantitative measures, assess the secondary effects on the left ventricle and aorta, then integrate everything with the clinical picture — and always ask whether it is acute.

Colour flow imaging of the AR is best performed by transthoracic echocardiography (TTE) on parasternal long-axis and short-axis views and three- or five-chamber apical views, and on the left ventricular outflow tract (LVOT) view obtained by transoesophageal echocardiography (TOE). (EACVI Textbook)

CW Doppler echocardiography, classically using apical views, allows measurement of the high-velocity AR flow. However, the right parasternal view (using the pencil probe) and particularly the left parasternal view are often the best views in the presence of an eccentric AR jet. (EACVI Textbook)

The PLAX, PSAX, apical three-chamber (A3C), and the apical five-chamber (A5C) views are typically used for assessment. The PLAX view is often used to provide assessment of aortic root pathology... The latter two views are best used for Doppler flow measurement. (Oxford Critical Care Echo)

The ME AV SAX view, with a transducer angle of 25-45 degrees, allows simultaneous assessment of the coronary cusps. (Oxford Critical Care Echo)

The ME aortic valve long axis view (ME AV LAX), with a transducer angle of 120-140 degrees, provides assessment and measurement of the LVOT, aortic root, and the proximal ascending aorta similar to that of the TTE at PLAX view. (Oxford Critical Care Echo)

The primary purpose of using the TG long axis (TG LAX) view, with transducer angle 120-140 degrees, and deep TG long axis view (Deep TG LAX), with transducer angle 0-20 degrees, is to direct the Doppler beam so that it is parallel to the blood flowing through the AV. (Oxford Critical Care Echo)

The aortic root (AoR) and ascending aorta (AscAo) should be measured from the PLAX window at three levels: the Sinus of Valsalva (SoV); the sino-tubular junction (STJ); and the AscAo defined as a level 1cm above the STJ. (BSE AR guideline 2025)

Continuous wave (CW) Doppler of the AR jet is classically best obtained from the apical five-chamber view. (EACVI valvular regurgitation recs)

It is useful to classify the mechanism of valve insufficiency into one of three subtypes: Type I AR is characterised by normal cusp motion within the context of aortic dilatation or cusp perforation; Type II describes excessive motion such as cusp prolapse; and Type III is the consequence of cusp restriction. In all cases, the mechanism of AR should be characterised descriptively. (BSE AR guideline 2025)

Originally designed for the mitral valve, Carpentier's classification has been adapted for use in the assessment of AR mechanism, whereby the lesion is classified according to cusp morphology and motion. Type I includes AR with normal cusp motion, where the insufficiency is secondary to aortic root dilatation or cusp perforation; Type II AR refers to excessive cusp motion including aortic cusp prolapse; those with restricted cusp motion are grouped in type III. (Tsampasian, Echo Res Pract 2023)

Type III AR is associated with poorer long-term outcomes after valve sparing surgery and a higher risk of recurrent AR post valve repair. (Tsampasian, Echo Res Pract 2023)

The Carpentier's classification is also commonly used to describe the mechanism of AR. Mechanisms of AR according to the Carpentier's functional classification: Type I, aortic annulus dilatation; Type IIa, prolapse of the left coronary cusp; Type III, rheumatic aortic valve disease with restricted cusp motion. (EACVI valvular regurgitation recs)

Note: the sources supplied use the descriptive three-subtype 'functional classification' (BSE) and Carpentier's classification (EACVI, Tsampasian); the named 'El Khoury' attribution does not appear verbatim in the fetched sources. (source note)

Two-dimensional echocardiography can show obvious structural abnormalities such as flail leaflet or diastolic coaptation defect. An eccentric jet is suggestive of aortic valve prolapse or perforation. (EACVI Textbook)

Flail valve or clear coaptation defect using 2D or 3D echocardiography is specific for moderate to severe or severe AR. (EACVI Textbook)

Calcification of a tricuspid aortic valve is usually most prominent in the central part of each cusp, with no commissural fusion. A stellate-shaped systolic orifice is observed on the parasternal short-axis view. (EACVI Textbook)

Infective endocarditis typically presents with mobile vegetations located on the ventricular aspect of the valve prolapsing into the LVOT. (Oxford Critical Care Echo)

Both 2D and M-mode imaging may provide an indirect measure of the severity of AR. The presence of a flail aortic leaflet is specific for the presence of severe AR. (Oxford Critical Care Echo)

The leaflets should be inspected for thickening, asymmetry or distortion of the cusps, and abnormalities in coaptation. (Practical Perioperative TOE)

If a regurgitant jet is identified with color flow Doppler imaging in the AV short-axis view, toggling the color map on and off will usually reveal a coaptation defect on 2-D imaging. However, if the scan plane passes through the body rather than the tips of the leaflets, the appearance may resemble a defect even with a normal valve. (Practical Perioperative TOE)

A grading system has been proposed: no calcification is classed as grade 1; small calcification spots (grade 2); larger calcification spots interfering with cusp motion is grade 3; extensive calcification causing restricted cusp motion is grade 4. (Tsampasian, Echo Res Pract 2023)

In patients with AR, careful aortic valve analysis is mandatory. The echo report should include information about the aetiology, the lesion process, and the type of dysfunction. The likelihood of valve repair should also be discussed in case of pure AR. (EACVI valvular regurgitation recs)

In practice, colour flow Doppler is used for the detection and initial visual assessment of AR. Eccentric jets are often associated with aortic valve prolapse or perforation. (EACVI Textbook)

The diameter of the jet at its origin is a semiquantitative colour Doppler index of AR severity. The maximum colour jet diameter (width) is measured in diastole immediately below the aortic valve (at the junction of the LV outflow tract and aortic annulus) on the parasternal long-axis view. (EACVI Textbook)

In the AV short-axis view, color flow Doppler is useful for determining the origin of the jet. A small central jet is consistent with mild regurgitation, and one that extends between the free edges of the leaflets is usually indicative of more severe disease. (Practical Perioperative TOE)

The colour flow area of the regurgitant jet, as a single parameter, is not recommended to quantify the severity of AR. The colour flow imaging should only be used for a visual assessment of AR. A more quantitative approach is required when more than a small central AR jet is observed. (EACVI valvular regurgitation recs)

Because of these variable characteristics, colour Doppler jet length or jet area from any window should not be used for assessing severity of AR. (BSE AR guideline 2025)

It is based on the principle that a small hemisphere of CFC with small jet expansion corresponds with mild regurgitation, whereas a large hemisphere of CFC with large jet expansion predicts severe AR. (BSE AR guideline 2025)

The CW Doppler density of the AR jet provides little information about the severity of AR. Although a faint spectral display is compatible with trace or mild AR, there is a significant overlap between CW Doppler density of moderate and severe AR. (EACVI Textbook)

The signal density (brightness) of a regurgitant jet is proportional to the blood flow across the AV in diastole, and this principle can be used as a simple qualitative guide to severity. It is helpful to compare the regurgitant jet with the antegrade flow signal to eliminate the confounding effect of differences in the Doppler gain setting. (Practical Perioperative TOE)

A weak or faint signal would indicate only mild regurgitation whereas a very dense signal is consistent with moderate or severe AR but is not able to conclusively differentiate the two. (BSE AR guideline 2025)

Both moderate and severe AR result in dense CW traces; ultimately, due to these limitations, CW signal density is not recommended to be used to quantify AR. (Tsampasian, Echo Res Pract 2023)

Spectral Doppler sampling of the regurgitant jet can be achieved from the transgastric views. Flow is toward the transducer (and therefore displayed above the baseline) and has an early peak velocity of 3 to 5 m/sec due to the high pressure gradient between the aorta and the left ventricle. (Practical Perioperative TOE)

A typical pressure difference between the Ao and LV will lead to an early diastolic peak velocity of approximately 4m/s on CW Doppler. (BSE AR guideline 2025)

The CW Doppler density of the AR jet does not provide useful information about the severity of AR. Because of the influence by chamber compliance and chamber pressures, it can only serve as a complementary finding for the assessment of AR severity. (EACVI valvular regurgitation recs)

Pulsed wave Doppler recording of flow in the descending aorta obtained on the suprasternal view is useful for assessment of AR severity. The sample volume is placed just distal to the origin of the left subclavian artery in the upper descending aorta, aligning it as closely as possible along the long axis of the aorta. (EACVI Textbook)

Moderate or severe AR is associated with holodiastolic reversal of flow in the aorta as well as increased systolic flow in the descending aorta. Milder degrees of regurgitation induce only a brief reversal of flow limited to early diastole. (EACVI Textbook)

An end-diastolic velocity greater than 20 cm/s is a strong and reliable argument in favour of severe AR. Underestimation and overestimation may occur when heart rate is low (< 50 bpm) or high (> 90 bpm), respectively. (EACVI Textbook)

Holodiastolic flow reversal within the descending thoracic aorta with an end-diastolic velocity ≥ 20cm/s is consistent with severe aortic regurgitation. The presence of diastolic flow reversal in the abdominal aorta is consistent with severe aortic regurgitation. (BSE AR guideline 2025)

Holodiastolic flow reversal with an end diastolic velocity ≥ 20cm/s in the descending thoracic Ao is both sensitive and highly specific for severe AR, whereas non-holodiastolic flow reversal is consistent with moderate AR. (BSE AR guideline 2025)

Holodiastolic flow reversal with end-diastolic velocity of ≥ 20cm/s was found to be a marker of severe AR and correlated well with a regurgitant fraction (RF) of ≥ 40% with a sensitivity and specificity of 88% and 96% respectively. Holodiastolic flow reversal in the abdominal aorta is also a highly specific marker of severe AR, but with moderate sensitivity. (Tsampasian, Echo Res Pract 2023)

It becomes sustained throughout diastole at velocities exceeding 20 cm/s in severe AR (end-diastolic velocity measured at peak R-wave). Significant holodiastolic reversal in the abdominal aorta is also a very specific sign of severe AR. The measurement of the diastolic flow reversal in the descending and abdominal aorta is recommended, when assessable. It should be considered as the strongest additional parameter for evaluating the severity of AR. (EACVI valvular regurgitation recs)

Early diastolic flow reversal in the descending thoracic aorta is a normal finding. A jet that extends... usually indicates severe regurgitation but may occur in the presence of moderate regurgitation. (Practical Perioperative TOE)

Elastic recoil within the aorta may lead to 'false positive' findings of diastolic flow reversal. (BSE AR guideline 2025)

This guideline recommends that aortic regurgitation (AR) is graded as either mild, moderate, or severe. (BSE AR guideline 2025)

BSE Table 14 grading (mild / moderate / severe):

Pressure half time (ms): mild >500, moderate 200-500, severe <200. (BSE AR guideline 2025)

Jet width/LVOTd (%): mild <25, moderate 25-65, severe >65. (BSE AR guideline 2025)

Vena contracta width (cm): mild <0.3, moderate 0.3-0.6, severe >0.6. (BSE AR guideline 2025)

Effective regurgitant orifice area (EROA) (cm2): mild <0.10, moderate 0.10-0.30, severe >0.30. (BSE AR guideline 2025)

Regurgitant volume (RVol) (mL): mild <30, moderate 30-60, severe >60. (BSE AR guideline 2025)

Regurgitant fraction (RF) (%): mild <30, moderate 30-50, severe >50. (BSE AR guideline 2025)

Diastolic flow reversal in the DAo: mild brief/none, moderate intermediate, severe prominent holodiastolic ≥ 20cm/s velocity. CW jet density: incomplete/faint (mild), dense (moderate), dense (severe). LV size: normal (mild) / dilated (severe). (BSE AR guideline 2025, Table 14)

The severity of AR can be confirmed if at least one quantitative / qualitative characteristic, one corroborative characteristic, and indexed left ventricular volumes are all in agreement. (BSE AR guideline 2025)

Multiparametric assessment, as recommended by the current international guidelines, is a useful approach in the evaluation of the AR severity, however it increases the risk of interobserver variability of AR assessment and leads to significant inconsistencies between the assessors. (Tsampasian, Echo Res Pract 2023)

EACVI/Oxford grading: VC width mild <0.3 cm, moderate 0.3-0.6 cm, severe >0.6 cm; EROA mild <0.1 cm2, moderate 0.1-0.3 cm2, severe >0.3 cm2; RVol mild <30 ml, moderate 30-60 ml, severe >60 ml; PHT mild >500 ms, moderate 200-500 ms, severe <200 ms; RF mild <30%, moderate 30-49%, severe >50%; Jet width/LVOT mild <0.25, moderate 0.25-0.65, severe >0.65. (Oxford Critical Care Echo, Table 15.2)

The vena contracta (VC) width represents the narrowest portion of the regurgitant jet and is a surrogate for the effective regurgitant orifice area. A VC < 0.3cm is consistent with mild or less AR, and a VC > 0.6cm is consistent with severe AR. VC width may under- or over-estimate AR severity in the context of a non-circular regurgitant orifice. (BSE AR guideline 2025)

The vena contracta is the smallest neck of the regurgitant jet at the level of the aortic valve, immediately below the flow convergence region, and is preferably measured on the parasternal long-axis view. (EACVI Textbook)

Using a Nyquist limit of 50-65 cm/s, a VCW greater than 6 mm is specific for severe AR, whereas mild AR is identified by VCW less than 3 mm. Intermediate vena contracta diameter values (3-6 mm) are inconclusive regarding the severity of AR. (EACVI Textbook)

In the case of multiple jets, the respective values of VCW are not additive and this parameter must not be used in such cases. (EACVI Textbook)

Using a Nyquist limit of 50-60 cm/s, a VC width of <3 mm correlates with mild AR, whereas a width >6 mm indicates severe AR. The measurement of the VC is affected by several factors as the presence of multiple jets. In this situation, the respective widths of the VC are not additive. (EACVI valvular regurgitation recs)

A VC of > 5mm correlates with severe AR with a sensitivity up to 95% and specificity between 80 and 90%, making it an excellent tool in the identification of severe AR. (Tsampasian, Echo Res Pract 2023)

A vena contracta width above 6 mm indicates severe regurgitation (regurgitant fraction >50%), and a width below 3 mm indicates mild or trivial regurgitation. (Practical Perioperative TOE)

A VC width of less than 0.3 cm correlates with mild AR, 0.3-0.6 cm is moderate, whereas a width greater than 0.6 cm is an indicator of severe AR. The use of VC has also been confirmed to be a reliable measurement, even in eccentric jets. (Oxford Critical Care Echo)

The effective regurgitant orifice area (ERO) and the regurgitant volume (RV) can be estimated by the flow convergence method, also called the PISA method. A clearly visible, hemispheric PISA is required for calculation. flow rate = 2 pi r2 x aliasing velocity, where r is the PISA radius. (EACVI Textbook)

Grading of the severity of AR... subclassifies moderate AR as 'mild-to-moderate' (EROA of 10-19 mm2 or an R Vol of 20 to 44 mL) and 'moderate-to-severe' (EROA of 20-29 mm2 or an R Vol of 45-59 mL). An EROA of 30 mm2 or greater, or an R Vol of 60 mL or more indicates severe AR. (EACVI Textbook)

An effective regurgitant orifice area (EROA) of > 0.3 cm2 is consistent with severe AR. Accurate calculation of EROA using the PISA method is limited in the setting of multiple and eccentric jets. (BSE AR guideline 2025)

The Nyquist limit baseline should be moved in the direction of regurgitant flow to between 0.2 and 0.4 cm/s; this optimises the hemisphere definition and facilitates measurement accuracy. (BSE AR guideline 2025)

A RVol of < 30mL is consistent with mild AR. A RVol of > 60mL is consistent with severe AR. A RF of < 30% is consistent with mild aortic regurgitation. A RF of > 50% is consistent with severe aortic regurgitation. (BSE AR guideline 2025)

An EROA ≥ 0.30cm2, regurgitant volume ≥ 60mls and regurgitant fraction > 50% all indicate severe AR. The EROA appears to be significantly underestimated when there is an obtuse flow convergence zone angle (> 220 degrees). (Tsampasian, Echo Res Pract 2023)

Quantification of the size of the proximal isovelocity surface area (PISA) on the aortic side of the valve in diastole is a useful method for assessing the severity of aortic regurgitation, particularly when the jet is eccentric. A PISA radius of more than 0.7 cm, at an aliasing velocity of 33 cm/sec, indicates severe regurgitation. (Practical Perioperative TOE)

When feasible, the PISA method is highly recommended to quantify the severity of AR. It can be used in both central and eccentric jets. In eccentric AR jets, we recommend to use the parasternal long-axis view to evaluate the flow convergence zone. An EROA ≥ 30 mm2 or an R Vol ≥ 60 mL indicates severe AR. (EACVI valvular regurgitation recs)

Aortic RV can be estimated by calculating using pulsed Doppler the difference between aortic inflow [total stroke volume (SV)] and mitral inflow (systemic stroke volume): AR RV = aortic inflow - mitral inflow. Regurgitant fraction is expressed as RV divided by aortic flow [total SV]. (EACVI Textbook)

Pressure half time (PHT) represents the time taken for the aortic-left ventricular (LV) pressure difference to fall to half its initial value. A PHT of < 200ms is consistent with severe aortic regurgitation (AR). A PHT of > 500ms is consistent with mild or less AR. LV compliance, LV dysfunction and hypertensive therapies may all affect the accuracy of the calculated PHT. (BSE AR guideline 2025)

The more severe the AR, the faster the equalisation of pressure, the steeper the AR deceleration slope and the shorter the PHT. (BSE AR guideline 2025)

A PHT shorter than 200 ms is a strong argument in favour of severe AR, whereas a value longer than 500 ms suggests mild AR... intermediate PHT values between 200 and 500 ms are not informative. In severe acute AR with high end-diastolic pressure, the PHT is almost always short. (EACVI Textbook)

A pressure half-time of <200 ms is consistent with severe AR, whereas a value >500 ms suggests mild AR. Of note, the pressure half-time is however influenced by chamber compliance, the acuteness of AR (i.e. in severe acute AR, the PHT is almost always short) and the aorto-ventricular pressure gradient. (EACVI valvular regurgitation recs)

The slope of the regurgitant jet can be quantified by the pressure half-time, which is the time it takes the diastolic pressure across the AV to fall by 50%. With severe regurgitation, the slope is typically steep and the pressure half-time short (<200 msec). A pressure half-time greater than 500 msec indicates mild regurgitation. (Practical Perioperative TOE)

Early work demonstrated that a PHT of 400ms can reliably identify important regurgitation, and angiographic grade 4 + AR correlates with a PHT of approximately 200ms. (Tsampasian, Echo Res Pract 2023)

For the same regurgitant volume, acute aortic regurgitation is associated with a shorter pressure half-time than chronic regurgitation, as the left ventricle is more compliant with the latter. (Practical Perioperative TOE)

Pressure half-time is shortened with increasing LV diastolic pressure, vasodilator therapy, and in patients with a dilated compliant aorta or lengthened in chronic AR. (EACVI valvular regurgitation recs)

Jet width / LVOTd ratio compares the colour flow jet width with the left ventricular outflow tract diameter. A ratio of < 25% is consistent with mild aortic regurgitation. A ratio of > 65% is consistent with severe aortic regurgitation. (BSE AR guideline 2025)

The maximum colour jet width is measured immediately below the AV with the PLAX view. A jet width/LVOT ratio of less than 25% correlates with mild AR, 25-64% is moderate, while a ratio of 65% or more is an indicator of severe AR. (Oxford Critical Care Echo)

Although these measurements are subject to relatively high inter-observer variability, a jet width ratio greater than 65% or a simple colour jet width greater than 12 mm is a strong argument in favour of severe AR. (EACVI Textbook)

Jet width, defined as the ratio of the jet diameter divided by the Left Ventricular Outflow Tract (LVOT) diameter, correlated well with the angiographically obtained grade of AR severity: a ratio of ≥ 65% being consistent with severe AR. (Tsampasian, Echo Res Pract 2023)

Measuring the jet height (width) relative to the diameter of the LVOT is a preferred method (ASE guidelines)... A ratio of jet height to LVOT diameter greater than 65% indicates severe regurgitation, while a ratio of less than 25% indicates mild regurgitation. With torrential aortic regurgitation, the jet may completely fill the LVOT. (Practical Perioperative TOE)

Determining the ratio of jet area to LVOT area is a preferred method (ASE guidelines)... A ratio below 25% is consistent with mild regurgitation, while a ratio above 60% is consistent with severe regurgitation. (Practical Perioperative TOE)

Its accuracy can thus be improved by normalizing the jet width for the LV outflow tract diameter... a jet width ratio >65% is a strong argument for severe AR. (EACVI valvular regurgitation recs)

Jet length and jet area are very much dependent on LV compliance and diastolic pressure, and do not reflect the severity of the AR; accordingly they are not recommended for use. (Tsampasian, Echo Res Pract 2023)

This method is unreliable with eccentric jets which may be transected by the alignment cursor and consequently underestimated... Conversely, a narrow regurgitant jet well-aligned with the CW Doppler beam, may appear dense and overestimate the AR severity. (BSE AR guideline 2025)

With eccentric jets, small errors in radius measurements are multiplied and may result in large inaccuracies in the calculation of EROA. (BSE AR guideline 2025)

Eccentric jets may be over- or underestimated with color flow Doppler, particularly when assessing aortic regurgitation by jet height and jet area. Eccentric jets are more reliably graded by the vena contracta and PISA methods. (Practical Perioperative TOE)

The mechanism of eccentric jets is usually leaflet prolapse, with the jet directed away from the prolapsing leaflet... the ratio of jet height to LVOT diameter would be falsely low and should not be used for grading severity in this circumstance. (Practical Perioperative TOE)

In the presence of eccentric jets, PISA tends to underestimate AR severity although these limitations can be overcome when the assessment is performed from the left parasternal instead of the apical window. (Tsampasian, Echo Res Pract 2023)

In the presence of eccentric jets, flow convergence zone from the PLAX view should be used instead, as apical views will underestimate the severity of the regurgitant jet. (Oxford Critical Care Echo)

As jet width is based on the assumption of a circular regurgitant orifice, when the orifice shape is irregular, as in the case of bicuspid valve, the colour jet width is less closely related to the degree of regurgitation. (EACVI Textbook)

Colour flow AR jet width: Large in central jet, variable in eccentric jets. In eccentric AR jets, we recommend to use the parasternal long-axis view to evaluate the flow convergence zone. (EACVI valvular regurgitation recs)

A high index of suspicion is required when undertaking echocardiography in such patients to ensure that acute severe AR is not missed. (BSE AR guideline 2025)

In the setting of very severe acute AR, due to markedly elevated left ventricular end diastolic pressures (LVEDP) and equalisation of LV and aortic end diastolic pressures, it is possible that there is no pressure difference thus resulting in curtailing of any diastolic flow reversal in the DAo. (BSE AR guideline 2025)

Interpretation of colour Doppler is challenging in acute severe AR... LV diastolic pressure rises rapidly as the non-compliant LV fills with blood from both the aorta and the left atrium during diastole. This results in the AR jet being of shorter duration and lower velocity, becoming therefore difficult to detect with colour flow Doppler only. (Tsampasian, Echo Res Pract 2023)

In severe acute AR, diastolic velocity decreases rapidly with no end-diastolic velocity due to early equalisation of aortic and LV diastolic pressures. (EACVI Textbook)

A lower peak velocity suggests that the true velocity is not being interrogated or that the regurgitation is very severe and the peak diastolic LV-LA pressure gradient is low. (Practical Perioperative TOE)

In cases of acute AR or when LV is impaired and there is reduced LV stroke volume, both the EROA and the regurgitant volume may underestimate the severity of AR: in such circumstances, the RF may be more useful at indicating severe AR. (Tsampasian, Echo Res Pract 2023)

In acute severe AR, the LV size is often normal. Hence, dilatation is sensitive for chronic significant AR while the normal size almost excludes severe chronic AR... or may be absent in acute severe AR. (EACVI valvular regurgitation recs)

BSE Table 13 red flags: LVESd > 50 mm; LVESdi ≥ 25 mm/m2; LVEF ≤ 55%; Ascending aorta diameter ≥ 55 mm in all patients; Ascending aorta diameter ≥ 45 mm in special populations; Rapid dilatation of the LV approaching surgical threshold. (BSE AR guideline 2025, Table 13)

AV surgery is therefore a Class I recommendation for patients with severe AR and impaired LV systolic function (LVEF ≤ 50%) or significantly dilated LV (LV end-systolic diameter > 50mm, indexed LV end-systolic diameter > 25mm/m2 or LV end-diastolic diameter > 65mm), even in the absence of symptoms. (Tsampasian, Echo Res Pract 2023)

ESC guidelines suggest the consideration of surgery when LVESDi > 20 mm/m2 or LVEF < 55% as class IIb recommendation in low-risk cases. (Tsampasian, Echo Res Pract 2023)

There was a significant increase in mortality with an LVESDi > 20 mm/m2, a markedly lower cut-off than the guideline-recommended surgical threshold. LVESD ≥ 45 mm was found to be an independent predictor of postsurgical mortality. (Tsampasian, Echo Res Pract 2023)

Indexed LV end-systolic volume (LVESVi) of 45 mL/m2 or greater is significantly associated with an increased risk of mortality and adverse events. Significant LV dilatation and severely reduced LV systolic function (defined as LVEF < 35%) are associated with poor postoperative short- and long-term outcomes. (Tsampasian, Echo Res Pract 2023)

In asymptomatic patients with chronic severe AR, surgery is indicated when left ventricular ejection fraction (LVEF) is less than 50% (Class I recommendation) or LVEF 50% or more, but LV end systolic diameter more than 50 mm (Class IIa). (Oxford Critical Care Echo)

Accepted cut-off values for non-significant LV enlargement: LV end-diastolic diameter < 56 mm, LV end-diastolic volume < 82 mL/m2, LV end-systolic diameter < 40 mm, LV end-systolic volume < 30 mL/m2. (EACVI valvular regurgitation recs)

The aortic root (AoR) and ascending aorta (AscAo) should be measured from the PLAX window at three levels: the Sinus of Valsalva (SoV); the sino-tubular junction (STJ); and the AscAo defined as a level 1cm above the STJ. (BSE AR guideline 2025)

Measurements should be performed at end-diastole, defined as the onset of the QRS on the surface electrocardiogram (ECG), using an inner-edge to inner-edge approach, with the measurement taken perpendicular to the major axis of the aorta. (BSE AR guideline 2025)

An Ao or ascending aorta (AscAo) dimension of ≥ 55mm in all patients is an indication for surgery. Special populations such as patients with Marfan syndrome, a BAV or aortic coarctation have a lower threshold, ranging between 45-50mm (and rarely 40mm). An aortic dimension ≥ 45mm in the presence of severe AR would usually prompt concomitant AoR replacement at the time of aortic valve intervention. (BSE AR guideline 2025)

The midesophageal AV long-axis view is used for measuring the dimensions of the AV annulus, sinuses, sinotubular junction, and proximal ascending aorta. The AV annulus should be measured at the points where the leaflets insert into the aorta. (Practical Perioperative TOE)

To measure these diameters accurately, it is essential that the image plane passes through the center of the aorta; this may require turning the shaft of the probe to the left or right to ensure the maximum aortic diameter is visualized. A clue that the image is off axis is a thickened appearance to one of the AV cusps or one of the aortic walls. (Practical Perioperative TOE)

TOE can also be performed to more precisely define the anatomy of the valve and the ascending aorta when a valve-sparing intervention is considered. (EACVI Textbook)

The left ventricle (LV) is often normal sized with normal or hyperdynamic LV systolic function. (BSE AR guideline 2025)

Echocardiographically, the LV will not necessarily be dilated, and often there will be normal or even hyperdynamic systolic function (despite the presence of pulmonary oedema) with concordant increases in LVOT velocities and the LVOT VTI. Additionally, there may be premature closure of the AV and premature termination of aortic flow as well as more indirect signs of acute severe AR including decreased transmitral deceleration time, premature closure of the MV, and diastolic MR. (BSE AR guideline 2025)

BSE Table 16 (Acute AR): LV size is not dilated; Hyperdynamic LV systolic function; Increased LVOT VTI / Vmax; Premature closure of the MV; Diastolic MR; High LVEDP; Decreased transmitral deceleration time; Premature termination of diastolic flow (AR duration may be brief). (BSE AR guideline 2025, Table 16)

When the regurgitant jet is eccentric, a high-frequency M-mode diastolic flutter of the anterior mitral leaflet is observed in about 80% of cases. This fluttering may also be observed on the mitral valve chordae or interventricular septum. (EACVI Textbook)

Severe acute aortic regurgitation. Example of premature mitral valve closure (left ventricular diastolic pressure exceeds left atrial diastolic pressure) assessed by M-mode. Example of diastolic mitral regurgitation using pulsed Doppler technique. (EACVI Textbook)

In addition, premature MV closure and high frequency fluttering of the anterior leaflet are also associated features of increasing acute AR severity as a result of rapidly increasing left ventricular diastolic pressure. (Oxford Critical Care Echo)

An additional sign suggestive of severe aortic regurgitation is the presence of presystolic closure of the MV. Occasionally, diastolic mitral regurgitation (identified by visualizing mitral and aortic regurgitation simultaneously in late diastole) may also be identified with color flow Doppler. (Practical Perioperative TOE)

Early mitral valve closure and diastolic mitral regurgitation (MR) are important echocardiographic signs that may alter the clinical course and management of patients with acute severe AR. (Tsampasian, Echo Res Pract 2023)

M-mode recording showing early mitral valve closure in a patient with severe AR; M-mode recording showing the fluttering motion of the anterior mitral leaflet in a patient with severe AR; premature diastolic opening of the aortic valve. (EACVI valvular regurgitation recs)

Severe aortic regurgitation leads to a rapid diastolic rise in LV pressure, which can cause closure of the MV before the onset of systole. This can be detected by capturing short color flow loops from the AV long-axis view and then (using the scroll function) seeking evidence of MV closure (in late diastole) before the aortic regurgitant jet disappears. (Practical Perioperative TOE)

Example of premature mitral valve closure (left ventricular diastolic pressure exceeds left atrial diastolic pressure) assessed by M-mode. (EACVI Textbook)

Premature MV closure... as a result of rapidly increasing left ventricular diastolic pressure. (Oxford Critical Care Echo)

Premature closure of the mitral valve may be categorised as grade I (up to 50ms before the Q wave) or as grade II (up to 200ms before the Q wave) and is a specific and sensitive indicator of acute severe AR. (Tsampasian, Echo Res Pract 2023)

More indirect signs of acute severe AR including decreased transmitral deceleration time, premature closure of the MV, and diastolic MR with the latter shown to be a predictor of decompensation. (BSE AR guideline 2025)

The presence of diastolic mitral regurgitation is an independent predictor of pulmonary oedema and/or haemodynamic instability in patients with acute severe AR. (Tsampasian, Echo Res Pract 2023)

In acute AR, the abrupt increase in backward blood flow into a normal size LV results in a marked elevation in end-diastolic pressure relative to the regurgitant volume. Impaired forward stroke volume yields a decreased systolic pressure and a narrow pulse pressure. Pulmonary oedema develops as a result of the rapidly raised LV end-diastolic pressure, LA pressure, and pulmonary capillary wedge pressure. (Oxford Critical Care Echo)

Compensatory tachycardia may preserve cardiac output initially, but eventually hypotension, organ failure, and other evidence of cardiogenic shock will develop. (Oxford Critical Care Echo)

Acute severe AR allows no such compensation; consequently, LV filling pressures and left atrial pressures become significantly elevated. Patients with acute severe AR usually present in extremis and frequently will be in overt or incipient cardiogenic shock, pulmonary oedema, or both. (BSE AR guideline 2025)

In acute severe AR, in light of the LVEDP rising rapidly, SV cannot be maintained despite intrinsic compensatory mechanisms. Echocardiographic findings consistent with acute severe AR need to be escalated urgently. (BSE AR guideline 2025)

The complex haemodynamic interaction of preload and afterload may further be complicated from intervention provided in the intensive care setting. For example, mechanical ventilation and administration of PEEP will reduce both preload and afterload, thus potentially reducing the severity of AR. (Oxford Critical Care Echo)

In these situations, integration of data derived from other haemodynamic adjuncts (i.e. pulmonary artery catheter), in addition to echocardiography findings, can provide an integrative approach in determining the severity of AR. (Oxford Critical Care Echo)

Patients with grade II early mitral valve closure usually suffer significant elevations in their LV diastolic pressure and volume which cannot be adequately compensated. Therefore, their presence suggests urgent surgical intervention. (Tsampasian, Echo Res Pract 2023)

Aortic regurgitation is less influenced by loading conditions than mitral regurgitation, but nevertheless, the hemodynamic state (volume status, heart rate, cardiac output, and LV afterload) can influence the severity of aortic regurgitation. (Practical Perioperative TOE)

Where image quality does not allow, or in circumstances where the quantitative / qualitative, corroborative, and LV volume do not align with regards to AR severity..., additional imaging is recommended. TOE is a useful adjunct to help clarify valve morphology, regurgitation mechanism and severity, and provides assessment for possible infection or dissection. TOE should also be considered pre-surgery where patients are undergoing aortic valve sparing or repair surgery, or any percutaneous procedures. (BSE AR guideline 2025)

TOE is helpful in patients who are non-echogenic on TTE, as TOE allows accurate assessment of the anatomy of the aortic leaflets and aortic root. TOE can be useful to identify the aetiology of AR (e.g. aortic dissection, bicuspid aortic valve, and aortic aneurysm) and for AR quantification. (EACVI Textbook)

TEE has an important role as the primary assessment tool in specific situations, notably in a critical-care setting when transthoracic windows may be suboptimal (e.g., in the assessment of AV endocarditis), in the assessment of aortic dissection, and in the evaluation of AV repair or prosthesis function following AV replacement. (Practical Perioperative TOE)

Should 2D TTE fail to provide a complete assessment of the regurgitant jet, a TOE may be required. (Oxford Critical Care Echo)

Imaging of the AV and LVOT morphology is best undertaken from the ME transducer position. TOE confirms presence of mildly... TOE should include both 2D and 3D imaging as well as colour and spectral Doppler modalities. (BSE AR guideline 2025)

DRUG-INDUCED / RARE AETIOLOGIES — Valvular abnormalities have been described in association with certain drugs such as anorectic drugs (fenfluramine, dexfenfluramine, and benfluorex), drugs used in the treatment of Parkinson's disease (ergot-derived dopamine agonists, pergolide, and cabergoline), or drugs used in the treatment of migraine (ergot alkaloid agents such as ergotamine and methysergide). (EACVI Textbook)

INFLAMMATORY AETIOLOGIES — Inflammatory processes and aortitis, and inflammatory diseases, such as systemic lupus erythematosus, rheumatoid arthritis, ankylosing spondylitis, Reiter syndrome, relapsing polychondritis, syphilis, Takayasu arteritis, or giant cell arteritis, constitute a heterogeneous group representing less than 5% of all aetiologies of AR. (EACVI Textbook)

DISSECTION MECHANISM — Dissection of the ascending aorta can result in AR due to dilatation of the sinuses with incomplete coaptation of the leaflets, extension of the dissection into the base of the leaflets, or prolapse of the intimal flap into the aortic valve. (EACVI Textbook)

BICUSPID DETAIL — Diastolic images may mimic a tricuspid aortic valve when a raphe is present. Fusion of right and left coronary cusps (large anterior and small posterior cusps with both coronary arteries arising from the anterior cusp) is the most frequent pattern. (EACVI Textbook)

BICUSPID CLASSIFICATION (raphe count) — Classification according the number of raphe... Bicuspid valve Type 0 (0 raphe, commissures at 1200), Type 1 (1 raphe, commissures at 1800), Type 2 (2 raphe, commissures at 1600). Unicuspid (UAV) and quadricuspid aortic valves (QAV) are rare, with an approximate prevalence of 0.02% and < 0.01% respectively. (EACVI Textbook / BSE AR guideline 2025)

M-MODE FLUTTERING CAVEAT — The absence of fluttering (e.g. in the case of mitral valve stenosis) cannot rule out the diagnosis of AR, and pseudofluttering can be observed in the presence of atrial fibrillation and cardiac hyperkinesia in patients without AR. (EACVI Textbook)

CARDIAC OUTPUT / VOLUMETRIC — A cardiac output greater than 10 L/min is a strong argument in favour of severe AR. (EACVI Textbook)

PHT SLOPE / 3D VC — A slope > 3 m/s2 is in favour of severe AR. Recent studies suggest that the cutoff for 3D VCA that best correlates with severe AR is ~ 0.30 mm2 [unit as printed]. (EACVI Textbook / BSE AR guideline 2025)

TOE VC NUMERIC — Multiplane colour Doppler TOE allows the measurement of VCW (angle 100-140 degrees) and area (angle 20-70 degrees): a value greater than 6 mm and greater than 7.5 mm2, respectively, are in favour of severe AR. (EACVI Textbook)

JET LENGTH (peri-op) — A jet that extends beyond the level of the papillary muscles is likely to be severe, and one that extends less than 2 cm beyond the level of the AV is likely to be mild. Not recommended by ASE guidelines. (Practical Perioperative TOE)

ACUTE MITRAL INFLOW — A restrictive mitral inflow pattern (short deceleration time < 150 ms, and E/A ratio > 2) is usually observed in severe acute AR. (EACVI Textbook)

PERI-OP CARDIOPLEGIA — Even the presence of mild aortic regurgitation is important, as it can complicate the administration of antegrade cardioplegia and may necessitate the placement of an LV venting device before arresting the heart. (Practical Perioperative TOE)

ALGORITHMIC GRADING — An algorithmic approach and hierarchical weighting of key echocardiographic parameters may be extremely helpful when grading the severity of AR. (Tsampasian, Echo Res Pract 2023)

PROLAPSE PREVALENCE — Aortic valve prolapse itself accounts for approximately 1.2% of all diagnosed AR lesions and may be encountered in patients with bicuspid AV and patients with aortic root disease, such as dissection or dilatation. (Tsampasian, Echo Res Pract 2023)

REVIEW ABSTRACT (Tak) — Aortic regurgitation is a valvular disorder that necessitates the integration of multiple aspects of clinical practice. The underlying etiologies span an array of pathologies, including congenital, infectious, structural, and traumatic causes. (Tak, Rev Cardiovasc Med 2025)