Impact of stroke volume assessment by three-dimensional transesophageal echocardiography on the classification of low-gradient aortic stenosis.

BACKGROUND: Accurate assessment of flow status is crucial in low-gradient aortic stenosis (AS). However, the clinical implication of three-dimensional transesophageal echocardiography (3DTEE) on flow status evaluation remains unclear. This study aimed to investigate the assessment of flow status using 3D TEE in low-gradient AS patients. METHODS: We retrospectively reviewed patients diagnosed with low-gradient AS and preserved ejection fraction at our institution between 2019 and 2022. Patients were categorized into low-flow/low-gradient (LF-LG) AS or normal-flow/low-gradient (NF-LG) AS based on two-dimensional transthoracic echocardiography (2DTTE). We compared the left ventricular outflow tract (LVOT) geometry between the two groups and reclassified them using stroke volume index (SVi) obtained by 3DTEE. RESULTS: Among 173 patients (105 with LF-LG AS and 68 with NF-LG AS), 54 propensity-matched pairs of patients were analyzed. 3DTEE-derived ellipticity index of LVOT was significantly higher in LF-LG AS patients compared to NF-LG AS patients (p = 0.012). We assessed the discordance in flow status classification between SVi2DTTE and SVi3DTEE in both groups using a cutoff value of 35 ml/m2. The LF-LG AS group exhibited a significantly higher discordance rate compared to the NF-LG AS group, with rates of 50% and 2%, respectively. The optimal cutoff values of SVi3DTEE for identifying low flow status, based on 2DTTE-derived cutoff values, were determined to be 43 ml/m2. CONCLUSIONS: LVOT ellipticity in low-gradient AS patients varies depending on flow status, and this difference contributes to discrepancies between SVi3DTEE and SVi2DTTE, particularly in LF-LG AS patients. Utilizing SVi3DTEE is valuable for accurately assessing flow status.

Echocardiographic Assessment of Aortic Stenosis under Sedation Underestimates Stenosis Severity.

BACKGROUND: Sedation can impact aortic stenosis (AS) classification, which depends on left ventricular ejection fraction (<≥ [less than or greater than and/or equal to] 50%), aortic valve area (AVA<≥ 1 cm2), mean pressure gradient (<≥ 40 mm Hg), peak velocity <≥ 400 cm/sec, and stroke volume index (SVI <≥35 mL/m2). We compared AS classification by transthoracic echo (TTE) during wakefulness versus sedation. METHODS: Immediately following a baseline TTE performed during wakefulness, another TTE was done during sedation delivered for a concomitant transesophageal study in 69 consecutive patients with AS (mean age 78 ± 7 years, 32 males). AVA was calculated through the continuity equation using the relevant hemodynamic parameters measured by each TTE study and same left ventricular outflow tract. AS class was defined as moderate, severe high gradient (HG), low ejection fraction low flow low gradient (LF-LG), paradoxical LF-LG (PLFLG), and normal flow low gradient (NF-LG). Based on conservative versus invasive treatment implication, AS classes were aggregated into group A (moderate AS and NFLG) and group B (HG, low-EF LF-LG, and PLFLG). RESULTS: During sedation, systolic and diastolic blood pressure decreased by 14.3 ± 29 and 8 ± 22 mm Hg, respectively, mean pressure gradient from 30.4 ± 10.9 to 27.2 ± 10.8 mm Hg, peak velocity from 345.3 ± 57.7 to 329.3 ± 64.8 cm/m2, and SVI from 41.5 ± 11.3 to 38.3 ± 11.8 mL/m2 (all P < .05). Calculated AVA was similar (delta = -0.009 ± 0.15 cm2). Individual discrepancies in hemodynamic parameters between the paired TTE studies resulted in an overall 17.4% rate of AS intergroup misclassification with sedation, with a relative risk of 1.09 of downgrade misclassification from group B to A versus upgrade misclassification (P < .001). CONCLUSIONS: Sedation TTE assessment downgrades AS severity in a significant proportion of patients, with a conversely smaller proportion of patients being upgraded, and therefore cannot be a substitute for wakefulness assessment.

Take home messages with cases from focused update on echocardiographic assessment of aortic stenosis.

Echocardiography plays an important role in the assessment of valvular aortic stenosis. Updated recommendations focusing on a stepwise approach to evaluating aortic stenosis have recently been published by the European Association of Cardiovascular Imaging and the American Society of Echocardiography. This review uses illustrative cases to demonstrate technical aspects of aortic stenosis assessment and use of the new proposed classification scheme for aortic stenosis. Key points from the updated recommendations reviewed in this paper are: (1) technical considerations and sources of error in measurement of peak velocity, mean aortic valve gradient and aortic valve area by continuity equation. (2) Application of flow status using indexed left ventricular stroke volume to distinguish patients with low gradients and a low calculated aortic valve area. (3) Use of low-dose dobutamine stress echocardiography in patients with low ejection fraction. (4) Application of the new classification scheme and review of algorithm use for echocardiographic evaluation of severe aortic stenosis. Improved understanding of how to handle unmatched variables and adopting an integrated approach to determine severity is central to guiding the clinician's management of aortic stenosis.

Imaging of Left Ventricular Hypertrophy: a Practical Utility for Differential Diagnosis and Assessment of Disease Severity.

PURPOSE OF REVIEW: Left ventricular hypertrophy (LVH) is often encountered in clinical practice, and it is a risk factor for cardiac mortality and morbidity. Determination of the etiology and disease severity is important for the management of patients with LVH. The aim of this review is to show the remarkable progress in cardiac imaging and its importance in clinical practice. RECENT FINDINGS: This review focuses on clinical features and characteristic cardiac imaging in LVH caused by various diseases including hypertension, aortic valve stenosis, hypertrophic cardiomyopathy, and secondary cardiomyopathies. The usefulness of echocardiography as a tool of general versatility including hemodynamic evaluation and the usefulness of cardiac magnetic resonance imaging for assessment of cardiac morphology and myocardial tissue characteristics of relevance for LVH are described. Imaging modalities now have central roles in the differentiation and prognostic assessment of LVH.

Multimodality Imaging Strategies for the Assessment of Aortic Stenosis: Viewpoint of the Heart Valve Clinic International Database (HAVEC) Group.

Aortic stenosis is the most frequent valvular heart disease. In aortic stenosis, therapeutic decision essentially depends on symptomatic status, stenosis severity, and status of left ventricular systolic function. Surgical aortic valve replacement or transcatheter aortic valve implantation is the sole effective therapy in symptomatic patients with severe aortic stenosis, whereas the management of asymptomatic patients remains controversial and is mainly based on individual risk stratification. Imaging is fundamental for the initial diagnostic work-up, follow-up, and selection of the optimal timing and type of intervention. The present review provides specific recommendations for utilization of multimodality imaging to optimize risk stratification and therapeutic decision-making processes in aortic stenosis.

Integration of 3D imaging data in the assessment of aortic stenosis: impact on classification of disease severity.

BACKGROUND: In patients with aortic stenosis (AS), precise assessment of severity is critical for treatment decisions. Estimation of aortic valve area (AVA) with transthoracic echocardiographic (TTE)-continuity equation (CE) assumes a circular left ventricular outflow tract (LVOT). We evaluated incremental utility of 3D multidetector computed tomography (MDCT) over TTE assessment of AS severity. METHODS AND RESULTS: We included 51 patients (age, 81±8 years; 61% men; mean gradient, 42 ± 12 mm Hg) with calcific AS who underwent evaluation for treatment options. TTE parameters included systolic LVOT diameter (D) and continuous and pulsed wave (CW and PW) velocity-time integrals (VTI) through the LVOT and mean transaortic gradient. MDCT parameters included systolic LVOT area, ratio of maximal to minimal LVOT diameter (eccentricity index), and aortic planimetry (AVA(p)). TTE-CE AVA [(D(2)×0.786×VTIpw)/VTIcw] and dimensionless index (DI) [VTIpw/VTIcw] were calculated. Corrected AVA was calculated by substituting MDCT LVOT area into CE. The majority (96%) of patients had eccentric LVOT. LVOT area, measured on MDCT, was higher than on TTE (3.84 ± 0.8 cm(2) versus 3.03 ± 0.5 cm(2), P<0.01). TTE-AVA was smaller than AVA(p) and corrected AVA (0.67 ± 0.1cm(2), 0.82 ± 0.3 cm(2), and 0.86 ± 0.3 cm(2), P<0.01). Using TTE measurements alone, 73% of patients had congruence for severe AS (DI ≤0.25 and CE AVA <0.8 cm(2)), which increased to 92% using corrected CE. CONCLUSIONS: In patients with suspected severe AS, incorporation of MDCT-LVOT area into CE improves congruence for AS severity.

[Diagnosis and assessment of severity of aortic valve stenosis]. / Diagnose und Schweregradbeurteilung bei Aortenklappenstenose.

Calcific aortic valve stenosis is the most common valvular heart disease in the elderly. Although the diagnosis can often be assumed at clinical presentation, determination of the disease severity is usually not accurately possible based on patient history and physical examination alone. In the past, invasive cardiac catheterization has been the most important strategy for assessing the hemodynamic severity of aortic stenosis. Nowadays, Doppler echocardiography has largely replaced invasive catheterization in many centers, since this modality allows for a comprehensive evaluation of the morphological and functional characteristics of the stenotic valve and for assessment of the prognosis of the disease. This article summarizes the current knowledge on the evaluation of aortic stenosis severity using Doppler echocardiography.

Use of the ejection fraction-velocity ratio in the hemodynamic assessment of aortic bioprosthetic valves.

BACKGROUND: A new echocardiographic severity index of aortic valve stenosis has been recently introduced: the ejection fraction-velocity ratio (EFVR), which is a simple ratio ejection fraction/4Vmax2. This nonflow corrected index demonstrated an excellent accuracy in quantifying the effective orifice area (EOA) in native aortic valves. There is no information about the reliability of EFVR in assessing aortic EOA in patients with bioprostheses. METHODS: In 141 consecutive patients with aortic bioprostheses (85 males, mean age 74 +/- 9 years), EOA was calculated by both continuity equation (CE) and EFVR. RESULTS: The correlation between CE and EFVR was highly significant (r = 0.88; P < 0.0001). The area under the receiver operating characteristic (ROC) curve was 0.97 (considering a positive case CE < 1.0 cm2, best cutoff of EFVR was <1.06). Using CE as gold standard and a cutoff of 1.0 for both indexes, EFVR showed good sensitivity (80%) and specificity (98%). Also in a subgroup of 46 patients with moderate or severe mitral regurgitation, the EFVR had a good diagnostic accuracy (sensitivity 89%, specificity 97%). In 91 patients with ejection fraction < or = 50%, the EFVR confirmed good sensitivity (79%) and specificity (97%). CONCLUSIONS: The EFVR, a simple and not time-consuming index, demonstrated a good diagnostic accuracy in assessing EOA also in patients with aortic bioprostheses. The presence of moderate to severe mitral regurgitation or left ventricular dysfunction does not reduce significantly the reliability of this new index. The EFVR can be taken into consideration in the clinical practice, at least when CE measurements are technically difficult.

Accurate assessment of aortic stenosis severity by Doppler echocardiography independent of aortic jet velocity.

The present investigation was designed to derive an accurate pulsed Doppler method of assessing aortic stenosis severity that does not rely on measurement of aortic jet velocity. Left ventricular ET and SV were determined from pulsed Doppler recordings of flow velocity at the aortic anulus in 44 mostly normotensive patients with aortic stenosis. Aortic valve area at catheterization ranged between 0.3 and 2.13 cm2. A predicted ET was derived from Doppler-determined SV with the use of a regression equation previously described by Harley et al. A significant inverse quadratic relation was observed between the ET difference (delta ET), defined as measured ET minus predicted ET, and valve area at catheterization (r = -0.87; valve area = 1.4 - 15 delta ET + 60 delta ET2; SEE = 0.23 cm2). An ET difference of greater than or equal to 0.060 second was 88% sensitive, 89% specific, and 89% accurate for detecting critical aortic stenosis. Thus the ET difference, derived from measurements of SV and ET by pulsed Doppler, is a sensitive index for detection of critical aortic stenosis that is independent of determination of aortic jet velocity. This index should complement the Doppler evaluation of aortic stenosis, especially in cases where interrogation of the stenotic jet with continuous wave Doppler is inadequate.