"Pure" severe aortic stenosis without concomitant valvular heart diseases: echocardiographic and pathophysiological features

Left Ventricular Mass, Myocardial Structure, and Function in Severe Aortic Stenosis: an Echocardiographic and Cardiac Magnetic Resonance Imaging Study

In severe aortic stenosis (AS), there are conflicting data on the prognostic implications of left ventricular (LV) hypertrophy (LVH). We aimed to characterize the LV geometry, myocardial matrix structural changes, and prognostic stratification using cardiac magnetic resonance imaging (CMR) and echocardiography in subjects with severe AS with and without LVH. Consecutive patients who had severe isolated AS and sufficient quality echocardiography and CMR within 6 months of each other were evaluated for LVH, cardiac structure, morphology, and late gadolinium-enhancement imaging. Kaplan-Meier curves, linear models, and proportional hazards models were used for prognostic stratification. There were 93 patients enrolled (mean age 74 ± 11 years, 48% female), of whom 38 (41%) had a normal LV mass index (LVMI), 41 (44%) had LVH defined at CMR by LVMI >2 SD higher than normal, and 14 (15% of the total) with >4 SD higher than the reference LVMI (severely elevated). The Society of Thoracic Surgeons scores were similar among the LVMI groups. Compared with those with normal LVMI, patients with LVH had higher LV end-diastolic and end-systolic volumes, increased late gadolinium-enhancement burden, and lower LV ejection fraction. Most notably, CMR feature-tracking global radial strain, 2-dimensional speckle-tracking echocardiography global longitudinal strain, and left atrial reservoir function were significantly worse. On the survival analyses, LVMI was not associated with a composite of all-cause mortality and/or heart failure hospitalization. In conclusion, compared with normal LVMI, elevated LVMI was not associated with a higher risk of adverse outcomes.

Improving accuracy in diagnosing aortic stenosis severity: An in-depth analysis of echocardiographic measurement error through literature review and simulation study

AIMS

The present guidelines advise replacing the aortic valve for individuals with severe aortic stenosis (AS) based on various echocardiographic parameters. Accurate measurements are essential to avoid misclassification and unnecessary interventions. The objective of this study was to evaluate the influence of measurement error on the echocardiographic evaluation of the severity of AS.

METHODS AND RESULTS

A systematic review was performed to examine whether measurement errors are reported in studies focusing on the prognostic value of peak aortic jet velocity (Vmax ), mean pressure gradient (MPG), and effective orifice area (EOA) in asymptomatic patients with AS. Out of the 37 studies reviewed, 17 (46%) acknowledged the existence of measurement errors, but none of them utilized methods to address them. Secondly, the magnitude of potential errors was collected from available literature for use in clinical simulations. Interobserver variability ranged between 0.9% and 8.3% for Vmax and MPG but was higher for EOA (range 7.7%-12.7%), indicating lower reliability. Assuming a circular left ventricular outflow tract area led to a median underestimation of EOA by 23% compared to planimetry by other modalities. A clinical simulation resulted in the reclassification of 42% of patients, shifting them from a diagnosis of severe AS to moderate AS.

CONCLUSIONS

Measurement errors are underreported in studies on echocardiographic assessment of AS severity. These errors can lead to misclassification and misdiagnosis. Clinicians and scientists should be aware of the implications for accurate clinical decision-making and assuring research validity.

Impact of Aortic Valve Regurgitation on Doppler Echocardiographic Parameters in Patients with Severe Aortic Valve Stenosis

BACKGROUND

Diagnosing severe aortic stenosis (AS) depends on flow and pressure conditions. It is suspected that concomitant aortic regurgitation (AR) has an impact on the assessment of AS severity. The aim of this study was to analyze the impact of concomitant AR on Doppler-derived guideline criteria. We hypothesized that both transvalvular flow velocity (maxV_AV) and the mean pressure gradient (mPG_AV) will be affected by AR, whereas the effective orifice area (EOA) and the ratio between maximum velocity of the left ventricular outflow tract and transvalvular flow velocity (maxV_LVOT/maxV_AV) will not. Furthermore, we hypothesized that EOA (by continuity equation), and the geometric orifice area (GOA) (by planimetry using 3D transesophageal echocardiography, TEE), will not be affected by AR.

METHODS AND RESULTS

In this retrospective study, 335 patients (mean age 75.9 ± 9.8 years, 44% male) with severe AS (defined by EOA < 1.0 cm²) who underwent a transthoracic and transesophageal echocardiography were analyzed. Patients with a reduced left ventricular ejection fraction (LVEF < 53%) were excluded (n = 97). The remaining 238 patients were divided into four subgroups depending on AR severity, and they were assessed using pressure half time (PHT) method: no, trace, mild (PHT 500-750 ms), and moderate AR (PHT 250-500 ms). maxV_AV, mPG_AV and maxV_LVOT/maxV_AV were assessed in all subgroups. Among the four subgroups (no (n = 101), trace (n = 49), mild (n = 61) and moderate AR (n = 27)), no differences were obtained for EOA (no AR: 0.75 cm² ± 0.15; trace AR: 0.74 cm² ± 0.14; mild AR: 0.75 cm² ± 0.14; moderate AR: 0.75 cm² ± 0.15, p = 0.998) and GOA (no AR: 0.78 cm² ± 0.20; trace AR: 0.79 cm² ± 0.15; mild AR: 0.82 cm² ± 0.19; moderate AR: 0.83 cm² ± 0.14, p = 0.424). In severe AS with moderate AR, compared with patients without AR, maxV_AV (p = 0.005) and mPG_AV (p = 0.022) were higher, whereas EOA (p = 0.998) and maxV_LVOT/maxV_AV (p = 0.243) did not differ. The EOA was smaller than the GOA in AS patients with trace (0.74 cm² ± 0.14 vs. 0.79 cm² ± 0.15, p = 0.024), mild (0.75 cm² ± 0.14 vs. 0.82 cm² ± 0.19, p = 0.021), and moderate AR (0.75 cm² ± 0.15 vs. 0.83 cm² ± 0.14, p = 0.024). In 40 (17%) patients with severe AS, according to an EOA < 1.0 cm², the GOA was ≥ 1.0 cm².

CONCLUSION

In severe AS with moderate AR, the maxV_AV and mPG_AV are significantly affected by AR, whereas the EOA and maxV_LVOT/maxV_AV are not. These results highlight the potential risk of overestimating AS severity in combined aortic valve disease by only assessing transvalvular flow velocity and the mean pressure gradient. Furthermore, in cases of borderline EOA, of approximately 1.0 cm², AS severity should be verified by determining the GOA.

Left ventricular hypertrophy, diastolic dysfunction and right ventricular load predict outcome in moderate aortic stenosis

Aims

Predictors of progression of moderate aortic valve stenosis (AS) are incompletely understood. The objective of this study was to evaluate the prognostic value of left ventricular hypertrophy (LVH), diastolic dysfunction, and right ventricular (RV) load in moderate AS.

Methods and results

Moderate AS was defined by aortic valve area (AVA), peak transvalvular velocity (V_max) or mean pressure gradient (PG_mean). A total of 131 Patients were divided into two groups according to the number of pathophysiological changes (LVH, diastolic dysfunction with increased LV filling pressures and/or RV load): <2 (group 1); ≥2 (group 2). The primary outcome was survival without aortic valve replacement (AVR). After follow-up of 30 months, the reduction of AVA (-0.06 ± 0.16 vs. -0.24 ± 0.19 cm², P < 0.001), the increase of PG_mean (2.89 ± 6.35 vs 6.29 ± 7.13 mmHg, P < 0.001) and the decrease of the global longitudinal strain (0.8 ± 2.56 vs. 1.57 ± 3.42%, P < 0.001) from baseline to follow-up were significantly more pronounced in group 2. Survival without AVR was 82% (group 1) and 56% (group 2) [HR 3.94 (1.74-8.94), P < 0.001]. Survival without AVR or progression of AS was 77% (group 1) and 46% (group 2) [HR 3.80 (1.84-7.86), P < 0.001]. The presence of ≥2 pathophysiological changes predicted outcome whereas age, comorbidities, LDL-cholesterol did not.

Conclusion

The presence of ≥2 pathophysiological changes is a strong predictor of outcome in moderate AS and may be useful for risk stratification, particularly for scheduling follow-up time intervals and deciding the timing of AVR.

The Evolution of Pulmonary Hypertension and Its Prognostic Implications Post-TAVI-Single Center Experience

Background and Objectives: Since the first transcatheter aortic valve implantation (TAVI) procedure was performed in 2002, advances in technology and refinement of the method have led to its widespread use in patients with severe aortic stenosis (AS) and high surgical risk. We aim to identify the impact of TAVI on the clinical and functional status of patients with severe AS at the one-month follow-up and to identify potential predictors associated with the evolution of pulmonary hypertension (PH) in this category of patients. Materials and Methods: We conducted a prospective study which included 86 patients diagnosed with severe AS undergoing TAVI treatment. We analyzed demographics, clinical and echocardiographic parameters associated with AS and PH both at enrolment and at the 30-day follow-up. Results: In our study, the decrease of EUROSCORE II score (p < 0.001), improvement of angina (p < 0.001) and fatigue (p < 0.001) as clinical benefits as well as a reduction in NYHA functional class in patients with heart failure (p < 0.001) are prognostic predictors with statistical value. Regression of left ventricular hypertrophy (p = 0.001), increase in the left ventricle ejection fraction (p = 0.007) and improvement of diastolic dysfunction (p < 0.001) are echocardiographic parameters with a prognostic role in patients with severe AS undergoing TAVI. The pulmonary artery acceleration time (PAAT) (p < 0.001), tricuspid annular plane systolic excursion (TAPSE) (p = 0.020), pulmonary arterial systolic pressure (PASP) (p < 0.001) and the TAPSE/PASP ratio (p < 0.001) are statistically significant echocardiographic parameters in our study that assess both PH and its associated prognosis in patients undergoing TAVI. Conclusions: PAAT, TAPSE, PASP and the TAPSE/PASP ratio are independent predictors that allow the assessment of PH and its prognostic implications post-TAVI.

[Functional Diagnostics by Rational Echocardiography]

Functional diagnostics by rational echocardiography are the base of a verifiable and reliable analysis of ventricular and valvular function. The most important functional parameters in echocardiography are cardiac volumes - especially total and effective left ventricular stroke volume -, global longitudinal strain, effective orifica areas in valvular stenoses and effective regurgitant volumes, regurgitant fraction and regurgitant orifice areas in valvular regurgitations. Standardized documentation and correct measurements are the prerequisites for accurate echocardiographic estimations. In addition, optimization of image quality supports the correctness of measurements to ensure plausibility of hemodynamics in each individual patient. However, measurements of cardiac volumes by planimetry are error-prone. In addition, calculation of the effective orifice areas using the continuity equation needs methodological accuracy and standardization. Finally, assessment of regurgitant volumes, regurgitant fraction, and regurgitant orifice is often inconsistent with stable hemodynamic conditions - especially by functional assessment the 2D-PISA method. Thus, functional diagnostics by echocardiography in valvular heart diseases should focus on a plausible hemodynamic assessment.

Severe Aortic Valve Stenosis and Pulmonary Hypertension: A Systematic Review of Non-Invasive Ways of Risk Stratification, Especially in Patients Undergoing Transcatheter Aortic Valve Replacement

Patients with severe aortic valve stenosis and concomitant pulmonary hypertension show a significantly reduced survival prognosis. Right heart catheterization as a preoperative diagnostic tool to determine pulmonary hypertension has been largely abandoned in recent years in favor of echocardiographic criteria. Clinically, determination of echocardiographically estimated systolic pulmonary artery pressure falls far short of invasive right heart catheterization data in terms of accuracy. The aim of the present systematic review was to highlight noninvasive possibilities for the detection of pulmonary hypertension in patients with severe aortic valve stenosis, with a special focus on cardiovascular biomarkers. A total of 525 publications regarding echocardiography, cardiovascular imaging and biomarkers related to severe aortic valve stenosis and pulmonary hypertension were analyzed in a systematic database analysis using PubMed Central®. Finally, 39 publications were included in the following review. It was shown that the current scientific data situation, especially regarding cardiovascular biomarkers as non-invasive diagnostic tools for the determination of pulmonary hypertension in severe aortic valve stenosis patients, is poor. Thus, there is a great scientific potential to combine different biomarkers (biomarker scores) in a non-invasive way to determine the presence or absence of PH.