Aortic valve area calculation in aortic stenosis by CT and Doppler echocardiography

Indexed aortic valve area using multimodality imaging for assessing the severity of bicuspid aortic stenosis

BACKGROUND

The impact of various imaging modalities on discordance/concordance between indexed aortic valve area (iAVA) and catheterization-derived mean transaortic pressure gradient (mPGcath) is unclear in patients with bicuspid aortic valve (BAV). This study aimed to compare iAVA measurements obtained using four different methodologies in BAV and tricuspid aortic valve (TAV) patients, using mPGcath as a reference standard.

METHODS

We retrospectively reviewed patients who underwent comprehensive assessment of AS, including two-dimensional (2D) transthoracic echocardiography (TTE), three-dimensional (3D) transesophageal echocardiography (TEE), multidetector computed tomography (MDCT), and catheterization, at our institution between 2019 and 2022. iAVA was measured using the continuity eq. (CE) with left ventricular outflow tract area obtained by 2D TTE, 3D TEE, and MDCT, as well as planimetric 3D TEE.

RESULTS AND CONCLUSIONS

Among 564 patients (64 with BAV and 500 with TAV), 64 propensity-matched pairs of patients with BAV and TAV were analyzed. iAVACE(2DTTE) led to overestimation of AS severity (BAV, 23.4%; TAV, 28.1%) and iAVACE(MDCT) led to underestimation of AS severity (BAV, 29.3%; TAV, 16.7%), whereas iAVACE(3DTEE) and iAVAPlani(3DTEE) resulted in a reduction in the discordance of AS grading. A moderate correlation was observed between mPGcath and iAVACE(3DTEE) (BAV, r = -0.63; TAV, r = -0.68), with iAVACE(3DTEE) corresponding to the current guidelines' cutoff value (BAV, 0.58 cm2/m2; TAV, 0.60 cm2/m2). Discordance/concordance between iAVA and mPGcath in evaluating AS severity varies depending on the methodology and imaging modality used. The use of iAVACE(3DTEE) is valuable for reconciling the discordant AS grading in BAV patients as well as TAV.

Normal-Flow Low-Gradient Aortic Stenosis: Comparing the U.S. and European Guidelines

Patients with normal-flow low-gradient (NFLG) severe aortic stenosis present both diagnostic and management challenges, with debate about the whether this represents true severe stenosis and the need for valve replacement. Studies exploring the natural history without intervention have shown similar outcomes of patients with NFLG severe aortic stenosis to those with moderate aortic stenosis and better outcomes after valve replacement than those with low-flow low-gradient severe aortic stenosis. Most studies (all observational) have shown that aortic valve replacement was associated with a survival benefit vs surveillance. Based on available data, the European Society of Cardiology/European Association for Cardio-Thoracic Surgery guidelines and European Association of Cardiovascular Imaging/American Society of Echocardiography suggest that these patients are more likely to have moderate aortic stenosis. This clinical entity is not mentioned in the American Heart Association/American College of Cardiology guidelines. Here we review the definition of NFLG severe aortic stenosis, potential diagnostic algorithms and points of error, the data supporting different management strategies, and the differing guidelines and outline the unanswered questions in the diagnosis and management of these challenging patients.

Quantification of anatomical aortic valve area by multi-detector computed tomography: A pilot 3D-morphological modeling of the stenotic aortic valve

BACKGROUND

Aortic-valve-stenosis (AS) is a frequent degenerative valvular-disease and carries dismal outcome under-medical-treatment. Transvalvular pressure gradient reflects severity of the valve-disease but is highly dependent on flow-conditions and on other valvular/aortic characteristics. Alternatively, aortic-valve-area (AVA) represents a measure of aortic-valve lesion severity conceptually essential and practically widely-recognized but exhibits multiple-limitations.

METHODS

We analyzed the 4D multi-detector computed tomography(MDCT) of 20 randomly selected patients with severe AS. For each-patient, we generated the 3D-model of the valve and of its calcifications, and we computed the anatomical AVA accounting for the 3D-morphology of the leaflets in three-different-ways. Finally, we compared our results vs. Doppler-based AVAE measurements and vs. 2D-planimetric AVA-measurements.

RESULTS

3D-reconstruction and identification of the cusps were successful in 90% of the cases. The calcification patterns where highly-variable over patients, ranging from multiple small deposits to wide and c-shaped deposits running from commissure-to-commissure. AVAE was 82 ± 15 mm2. When segmenting 18 image planes, AVATight, AVAProj-Ann, AVAProj-Tip and their average AVAAve were equal to 80 ± 16, 88 ± 20, 93 ± 21 and 87 ± 19 mm2, respectively, while AVAPlan was equal to 143 ± 50 mm2. Linear-regression of the three measurements vs. AVAE yielded regression slopes equal to 1.26, 1.13 and 0.93 for AVAProj-Ann, AVAProj-Tip and AVATight, respectively. The respective Pearson-coefficients were 0.85,0.86 and 0.90. Conversely, when comparing AVAPlan vs. AVAE, linear regression yielded a slope of 1.73 and a Pearson coefficient of 0.53.

CONCLUSIONS

We described a new-method to obtain a set of flow-independent quantifications that complement pressure gradient measurements and combine the advantages of previously proposed methods, while bypassing the corresponding-limitations.

Moderate aortic stenosis: Navigating the uncharted

Aortic stenosis (AS) stands as the most common valvular heart disease in developed countries and is characterized by progressive narrowing of the aortic valve orifice resulting in elevated transvalvular flow resistance, left ventricular hypertrophy, and progressive increased risk of heart failure and sudden death. This narrative review explores clinical challenges and evolving perspectives in moderate AS, where discrepancies between aortic valve area and pressure gradient measurements may pose diagnostic and therapeutic quandaries. Transthoracic echocardiography is the first-line imaging modality for AS evaluation, yet cases of discordance may require the application of ancillary noninvasive diagnostic modalities. This review underscores the importance of accurate grading of AS severity, especially in low-gradient phenotypes, emphasizing the need for vigilant follow-up. Current clinical guidelines primarily recommend aortic valve replacement for severe AS, potentially overlooking latent risks in moderate disease stages. The noninvasive multimodality imaging approach-including echocardiography, cardiac magnetic resonance, computed tomography, and nuclear techniques-provides unique insights into adaptive and maladaptive cardiac remodeling in AS and offers a promising avenue to deliver precise indications and exact timing for intervention in moderate AS phenotypes and asymptomatic patients, potentially improving long-term outcomes. Nevertheless, what we may have gleaned from a large amount of observational data is still insufficient to build a robust framework for clinical decision-making in moderate AS. Future research will prioritize randomized clinical trials designed to weigh the benefits and risks of preemptive aortic valve replacement in the management of moderate AS, as directed by specific imaging and nonimaging biomarkers.

Diagnostic Challenges in Aortic Stenosis

Aortic stenosis (AS) is the most prevalent degenerative valvular disease in western countries. Transthoracic echocardiography (TTE) is considered, nowadays, to be the main imaging technique for the work-up of AS due to high availability, safety, low cost, and excellent capacity to evaluate aortic valve (AV) morphology and function. Despite the diagnosis of AS being considered straightforward for a very long time, based on high gradients and reduced aortic valve area (AVA), many patients with AS represent a real dilemma for cardiologist. On the one hand, the acoustic window may be inadequate and the TTE limited in some cases. On the other hand, a growing body of evidence shows that patients with low gradients (due to systolic dysfunction, concentric hypertrophy or coexistence of another valve disease such as mitral stenosis or regurgitation) may develop severe AS (low-flow low-gradient severe AS) with a similar or even worse prognosis. The use of complementary imaging techniques such as transesophageal echocardiography (TEE), multidetector computed tomography (MDTC), or cardiac magnetic resonance (CMR) plays a key role in such scenarios. The aim of this review is to summarize the diagnostic challenges associated with patients with AS and the advantages of a comprehensive multimodality cardiac imaging (MCI) approach to reach a precise grading of the disease, a crucial factor to warrant an adequate management of patients.

Aortic Valve Calcification Density Measured by MDCT in the Assessment of Aortic Stenosis Severity

BACKGROUND

Aortic valve calcification (AVC) indexation to the aortic annulus (AA) area measured by Doppler echocardiography (AVCdEcho) provides powerful prognostic information in patients with aortic stenosis (AS). However, the indexation by AA measured by multidetector computed tomography (AVCdCT) has never been evaluated. The aim of this study was to compare AVC, AVCdCT, and AVCdEcho with regard to hemodynamic correlations and clinical outcomes in patients with AS.

METHODS

Data from 889 patients, mainly White, with calcific AS who underwent Doppler echocardiography and multidetector computed tomography within the same episode of care were retrospectively analyzed. AA was measured both by Doppler echocardiography and multidetector computed tomography. AVCdCT severity thresholds were established using receiver operating characteristic curve analyses in men and women separately. The primary end point was the occurrence of all-cause mortality.

RESULTS

Correlations between gradient/velocity and AVCd were stronger (both P≤0.005) using AVCdCT (r=0.68, P<0.001 and r=0.66, P<0.001) than AVC (r=0.61, P<0.001 and r=0.60, P<0.001) or AVCdEcho (r=0.61, P<0.001 and r=0.59, P<0.001). AVCdCT thresholds for the identification of severe AS were 334 Agatston units (AU)/cm2 for women and 467 AU/cm2 for men. On a median follow-up of 6.62 (6.19-9.69) years, AVCdCT ratio was superior to AVC ratio and AVCdEcho ratio to predict all-cause mortality in multivariate analyses (hazard ratio [HR], 1.59 [95% CI, 1.26-2.00]; P<0.001 versus HR, 1.53 [95% CI, 1.11-1.65]; P=0.003 versus HR, 1.27 [95% CI, 1.11-1.46]; P<0.001; all likelihood test P≤0.004). AVCdCT ratio was superior to AVC ratio and AVCdEcho ratio to predict survival under medical treatment in multivariate analyses (HR, 1.80 [95% CI, 1.27-1.58]; P<0.001 compared with HR, 1.55 [95% CI, 1.13-2.10]; P=0.007; HR, 1.28 [95% CI, 1.03-1.57]; P=0.01; all likelihood test P<0.03). AVCdCT ratio predicts mortality in all subgroups of patients with AS.

CONCLUSIONS

AVCdCT appears to be equivalent or superior to AVC and AVCdEcho to assess AS severity and predict all-cause mortality. Thus, it should be used to evaluate AS severity in patients with nonconclusive echocardiographic evaluations with or without low-flow status. AVCdCT thresholds of 300 AU/cm2 for women and 500 AU/cm2 for men seem to be appropriate to identify severe AS. Further studies are needed to validate these thresholds, especially in diverse populations.

Influence of cusp morphology and sex on quantitative valve composition in severe aortic stenosis

AIMS

Aortic stenosis is characterized by fibrosis and calcification of the valve, with a higher proportion of fibrosis observed in women. Stenotic bicuspid aortic valves progress more rapidly than tricuspid valves, which may also influence the relative composition of the valve. We aimed to investigate the influence of cusp morphology on quantitative aortic valve composition quantified from contrast-enhanced computed tomography angiography in severe aortic stenosis.

METHODS AND RESULTS

Patients undergoing transcatheter aortic valve implantation with bicuspid and tricuspid valves were propensity matched 1:1 by age, sex, and comorbidities. Computed tomography angiograms were analysed using semi-automated software to quantify the fibrotic and calcific scores (volume/valve annular area) and the fibro-calcific ratio (fibrotic score/calcific score). The study population (n = 140) was elderly (76 ± 10 years, 62% male) and had a peak aortic jet velocity of 4.1 ± 0.7 m/s. Compared with those with tricuspid valves (n = 70), patients with bicuspid valves (n = 70) had higher fibrotic scores [204 (interquartile range 118-267) vs. 144 (99-208) mm3/cm2, P = 0.006] with similar calcific scores (P = 0.614). Women had greater fibrotic scores than men in bicuspid [224 (181-307) vs. 169 (109-247) mm3/cm2, P = 0.042] but not tricuspid valves (P = 0.232). Men had greater calcific scores than women in both bicuspid [203 (124-355) vs. 130 (70-182) mm3/cm2, P = 0.008] and tricuspid [177 (136-249) vs. 100 (62-150) mm3/cm2, P = 0.004] valves. Among both valve types, women had a greater fibro-calcific ratio compared with men [tricuspid 1.86 (0.94-2.56) vs. 0.86 (0.54-1.24), P = 0.001 and bicuspid 1.78 (1.21-2.90) vs. 0.74 (0.44-1.53), P = 0.001].

CONCLUSIONS

In severe aortic stenosis, bicuspid valves have proportionately more fibrosis than tricuspid valves, especially in women.

Multimodality assessment of high- vs. low-gradient aortic stenosis using echocardiography and cardiac CT

BACKGROUND

Aortic valve area (AVA) using CT-LVOT area (AVACT-LVOT) <1.2 ​cm2 has been shown comparable to echocardiography AVA of <1.0 ​cm2 for severe aortic stenosis (AS). Current study evaluates how AS diagnosis will be affected when we substitute CT-LVOT with echo derived LVOT.

METHODS

We retrospectively studied 367 patients who underwent cardiac CTA and echocardiogram for assessment of high- and low-gradient AS (HG-AS and LG-AS). AVACT-LVOT was derived from CT-LVOT area and echo doppler data. Three AVACT-LVOT categories were created (<1.0, 1.0-1.2 and ​> ​1.2 ​cm2). Outcomes were defined as composite of all-cause mortality and/or valve intervention.

RESULTS

Median echocardiographic profiles were consistent with severe AS across three AVACT-LVOT categories for HG-AS. HG-AS patients with AVACT-LVOT >1.2 ​cm2 had larger median CT-LVOT area (5.06 ​cm2) and AVC (2917AU). Among LG-AS with AVACT-LVOT ​≤1.2 cm2, 57% met echo criteria for low-flow LG-AS and 63% met criteria for severe AS using aortic valve calcium (AVC). Additionally, 45% with AVACT-LVOT >1.2 ​cm2 had larger median CT-LVOT area (5.43 ​cm2) and AVC (2389AU). Patients with AVACT-LVOT >1.2 ​cm2 and high AVC had large body surface area and were mostly characterized as severe with indexed AVA and AVC. Stroke volume index using CT-LVOT reclassified 70% of low-flow, LG-AS as normal flow, LG-AS. Composite outcomes were higher among patients with AVACT-LVOT ≤1.2 ​cm2 (p ​< ​0.01), however, with no superior net reclassification improvement compared to AVAecho <1.0 ​cm2.

CONCLUSION

AVACT-LVOT ≤1.2 ​cm2 is a reasonable CT criterion for severe AS. Large LVOT with elevated AVC identified a severe AS phenotype despite an AVACT-LVOT >1.2 ​cm2, best characterized by indexed AVA and AVC.

Multi-modality imaging in aortic stenosis: an EACVI clinical consensus document

In this EACVI clinical scientific update, we will explore the current use of multi-modality imaging in the diagnosis, risk stratification, and follow-up of patients with aortic stenosis, with a particular focus on recent developments and future directions. Echocardiography is and will likely remain the key method of diagnosis and surveillance of aortic stenosis providing detailed assessments of valve haemodynamics and the cardiac remodelling response. Computed tomography (CT) is already widely used in the planning of transcutaneous aortic valve implantation. We anticipate its increased use as an anatomical adjudicator to clarify disease severity in patients with discordant echocardiographic measurements. CT calcium scoring is currently used for this purpose; however, contrast CT techniques are emerging that allow identification of both calcific and fibrotic valve thickening. Additionally, improved assessments of myocardial decompensation with echocardiography, cardiac magnetic resonance, and CT will become more commonplace in our routine assessment of aortic stenosis. Underpinning all of this will be widespread application of artificial intelligence. In combination, we believe this new era of multi-modality imaging in aortic stenosis will improve the diagnosis, follow-up, and timing of intervention in aortic stenosis as well as potentially accelerate the development of the novel pharmacological treatments required for this disease.

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.

Performance of Computed Tomographic Angiography-Based Aortic Valve Area for Assessment of Aortic Stenosis

Background A total of 40% of patients with severe aortic stenosis (AS) have low-gradient AS, raising uncertainty about AS severity. Aortic valve calcification, measured by computed tomography (CT), is guideline-endorsed to aid in such cases. The performance of different CT-derived aortic valve areas (AVAs) is less well studied. Methods and Results Consecutive adult patients with presumed moderate and severe AS based on echocardiography (AVA measured by continuity equation on echocardiography <1.5 cm2) who underwent cardiac CT were identified retrospectively. AVAs, measured by direct planimetry on CT (AVACT) and by a hybrid approach (AVA measured in a hybrid manner with echocardiography and CT [AVAHybrid]), were measured. Sex-specific aortic valve calcification thresholds (≥1200 Agatston units in women and ≥2000 Agatston units in men) were applied to adjudicate severe or nonsevere AS. A total of 215 patients (38.0% women; mean±SD age, 78±8 years) were included: normal flow, 59.5%; and low flow, 40.5%. Among the different thresholds for AVACT and AVAHybrid, diagnostic performance was the best for AVACT <1.2 cm2 (sensitivity, 85%; specificity, 26%; and accuracy, 72%), with no significant difference by flow status. The percentage of patients with correctly classified AS severity (correctly classified severe AS+correctly classified moderate AS) was as follows; AVA measured by continuity equation on echocardiography <1.0 cm2, 77%; AVACT <1.2 cm2, 73%; AVACT <1.0 cm2, 58%; AVAHybrid <1.2 cm2, 59%; and AVAHybrid <1.0 cm2, 45%. AVACT cut points of 1.52 cm2 for normal flow and 1.56 cm2 for low flow, provided 95% specificity for excluding severe AS. Conclusions CT-derived AVAs have poor discrimination for AS severity. Using an AVACT <1.2-cm2 threshold to define severe AS can produce significant error. Larger AVACT thresholds improve specificity.

Differences in aortic valve area measured on cardiac CT and echocardiography in patients with aortic stenosis

BACKGROUND

A certain proportion of patients with severe aortic stenosis (AS) present with discordant grading between different diagnostic modalities, which raises uncertainty about the true severity of AS. The aim of this study was to compare the aortic valve area (AVA) measured on CT and echocardiography and demonstrate the factors affecting AVA discrepancies.

METHODS

Between June 2011 and March 2016, 535 consecutive patients (66.83±8.80 years, 297 men) with AS who underwent pre-operative cardiac CT and echocardiography for aortic valve replacement were retrospectively included. AVA was obtained by AVA on echocardiography (AVAecho) and CT (AVACT) using a measurement of the left ventricular outflow tract on each modality and correlations between those measures were evaluated. Logistic regression analysis was performed to identify factors affecting the discordance for grading severe AS.

RESULTS

The AVACT and AVAecho showed a high correlation (r: 0.79, P <0.001) but AVACT was larger than the AVAecho (difference 0.26 cm2, P <0.001). By using the cut-off values of AVACT (<1.2 cm2) and AVAecho (<1.0 cm2) for diagnosing severe AS, the BSA (odds ratio [OR]: 68.03, 95% confidence interval [CI]: 5.45-849.99; P = 0.001), AVAecho (OR: 1.19, 95%CI: 1.14-1.24; P <0.001), tricuspid valve morphology (OR: 2.83, 95%CI: 1.23-6.50; P = 0.01), and normalized annulus area (OR: 1.02; 95%CI:1.02-1.03; P <0.001) were significant factors associated with the discordance between the AVAecho and AVACT.

CONCLUSION

Patients with larger BSA, AVAecho, and annulus, and tricuspid valve morphology were associated with the AVA discordance between the echocardiography and CT. Complementary use of CT with echocardiography for grading severe AS could be helpful in such conditions.

Assessment of Calcium Score Cutoff Point for Clinically Significant Aortic Stenosis on Lung Cancer Screening Program Low-Dose Computed Tomography-A Cross-Sectional Analysis

Low-dose computed tomography (LDCT) is predominantly applied in lung cancer screening programs. Tobacco smoking is the main risk factor for developing lung cancer but is also common for cardiovascular diseases, including aortic stenosis (AS). Consequently, an increased prevalence of cardiovascular diseases is expected in lung cancer screenees. Therefore, initial aortic valve calcification evaluation should be additionally performed on LDCT. The aim of this study was to estimate a calcium score (CS) cutoff point for clinically significant AS diagnosis based on LDCT, confirmed by echocardiographic examination. The study included 6631 heavy smokers who participated in a lung cancer screening program (MOLTEST BIS). LDCTs were performed on all individuals and were additionally assessed for aortic valve calcification with the use of CS according to the Agatston method. Patients with CS ≥ 900 were referred for echocardiography to confirm the diagnosis of AS and to evaluate its severity. Of 6631 individuals, 54 met the inclusion criteria and underwent echocardiography for confirmation and assessment of AS. Based on that data, receiver operating characteristic (ROC) curves of CS were plotted, and cutoff points for clinically significant AS diagnosis were established: A CS of 1758 for at least moderate AS had 85.71% (CI 65.36-95.02%) sensitivity and 75.76% (CI 58.98-87.17%) specificity; a CS of 2665 for severe AS had 87.5% (CI 73.89-94.54%) sensitivity and 76.92% (CI 49.74-91.82%) specificity. This is the first study to assess possible CS cutoff points for diagnosing clinically significant AS detected by LDCT in lung cancer screening participants. LDCT with CS assessment could enable early detection of patients with clinically significant AS and therefore identify patients who require appropriate treatment.

Multimodality imaging in aortic stenosis: new diagnostic and therapeutic frontiers

The advent of transcatheter aortic valve implantation has revolutionized the treatment of calcific aortic valve stenosis. Elderly patients who were previously considered inoperable have currently an efficacious and safe therapy that provides better survival. In addition, current practice guidelines tend to recommend earlier intervention to avoid the irreversible consequences of long-lasting pressure overload caused by the stenotic aortic valve. Appropriate timing of the intervention relies significantly on imaging techniques that provide information on the severity of the aortic stenosis as well as on the hemodynamic consequences and cardiac remodeling. While left ventricular ejection fraction remains one of the main functional parameters for risk stratification in patients with severe aortic stenosis, advances in imaging techniques have provided new structural and functional parameters that allow the identification of patients who will benefit from intervention before the occurrence of symptoms or irreversible cardiac damage. Furthermore, ongoing research aiming to identify the medical therapies that can effectively halt the progression of aortic stenosis relies heavily on imaging endpoints, and new imaging techniques that characterize the metabolic activity of calcific aortic stenosis have been proposed to monitor the effects of these therapies. The present review provides an up-to-date overview of the imaging advances that characterizes the pathophysiology and that have changed the management paradigm of aortic stenosis.

Recommendations for the Use of Echocardiography in the Evaluation of Rheumatic Heart Disease: A Report from the American Society of Echocardiography

Acute rheumatic fever and its chronic sequela, rheumatic heart disease (RHD), pose major health problems globally, and remain the most common cardiovascular disease in children and young people worldwide. Echocardiography is the most important diagnostic tool in recognizing this preventable and treatable disease and plays an invaluable role in detecting the presence of subclinical disease needing prompt therapy or follow-up assessment. This document provides recommendations for the comprehensive use of echocardiography in the diagnosis and therapeutic intervention of RHD. Echocardiographic diagnosis of RHD is made when typical findings of valvular and subvalvular abnormalities are seen, including commissural fusion, leaflet thickening, and restricted leaflet mobility, with varying degrees of calcification. The mitral valve is predominantly affected, most often leading to mitral stenosis. Mixed valve disease and associated cardiopulmonary pathology are common. The severity of valvular lesions and hemodynamic effects on the cardiac chambers and pulmonary artery pressures should be rigorously examined. It is essential to take advantage of all available modalities of echocardiography to obtain accurate anatomic and hemodynamic details of the affected valve lesion(s) for diagnostic and strategic pre-treatment planning. Intraprocedural echocardiographic guidance is critical during catheter-based or surgical treatment of RHD, as is echocardiographic surveillance for post-intervention complications or disease progression. The role of echocardiography is indispensable in the entire spectrum of RHD management.

Assessment of aortic valve area on cardiac computed tomography in symptomatic bicuspid aortic stenosis: Utility and differences from Doppler echocardiography

Background

In this study, we investigate the utility of geometric orifice area (GOA) on cardiac computed tomography (CT) and differences from effective orifice area (EOA) on Doppler echocardiography in patients with bicuspid aortic stenosis (AS).

Methods

A total of 163 patients (age 64 ± 10 years, 56.4% men) with symptomatic bicuspid AS who were referred for surgery and underwent both cardiac CT and echocardiography within 3 months were studied. To calculate the aortic valve area, GOA_CT was measured by multiplanar CT planimetry, and EOA_Echo was calculated by the continuity equation with Doppler echocardiography. The relationships between GOA_CT and EOA_Echo and patient symptom scale, biomarkers, and left ventricular (LV) functional variables were analyzed.

Results

There was a significant but modest correlation between EOA_Echo and GOA_CT (r = 0.604, p < 0.001). Both EOA_Echo and GOA_CT revealed significant correlations with mean pressure gradient and peak transaortic velocity, and the coefficients were higher in EOA_Echo than in GOA_CT. EOA_Echo of 1.05 cm² and GOA_CT of 1.25 cm² corresponds to hemodynamic cutoff values for diagnosing severe AS. EOA_Echo was well correlated with the patient symptom scale and log NT-pro BNP, but GOA_CT was not. In addition, EOA_Echo had a higher correlation coefficient with estimated LV filling pressure and LV global longitudinal strain than GOA_CT.

Conclusion

GOA_CT can be used to evaluate the severity of bicuspid AS. The threshold for GOA_CT for diagnosing severe AS should be higher than that for EOA_Echo. However, EOA_Echo is still the method of choice because EOA_Echo showed better correlations with clinical and functional variables than GOA_CT.

Quantification of Significant Aortic Stenosis by Echocardiography versus Four-Dimensional Cardiac Computed Tomography: A Multi-Modality Imaging Study

Transthoracic echocardiography (TTE) grading of aortic stenosis (AS) is challenging when parameters are discrepant, and four-dimensional cardiac computed tomography (4D-CCT) is increasingly utilized for transcatheter intervention workup. We compared TTE and 4D-CCT measures contributing to AS quantification. AS patients (n = 80, age 86 ± 10 years, 71% men) referred for transcatheter replacement in 2014−2017 were retrospectively studied, 20 each with high-gradient AS (HG-AS), classical and paradoxical low-flow low-gradient AS (CLFLG-AS and PLFLG-AS), and normal-flow low-gradient AS (NFLG-AS). Correlation and Bland−Altman analyses were performed between TTE and 4D-CCT parameters. There were moderate-to-high TTE versus 4D-CCT correlations for left ventricular volumes, function, mass, and outflow tract dimensions (r = 0.51−0.88), though values were mostly significantly higher by 4D-CCT (p < 0.001). Compared with 4D-CCT planimetry of aortic valve area (AVA), TTE estimates had modest correlation (r = 0.37−0.43) but were significantly lower (by 0.15−0.32 cm2). The 4D-CCT estimate of LVSVi lead to significant reclassification of AS subtype defined by TTE. In conclusion, 4D-CCT quantified values were higher than TTE for the left ventricle and AVA, and the AS subtype was reclassified based on LVSVi by 4D-CCT, warranting further research to establish its clinical implications and optimal thresholds in severe AS management.

Imaging, Treatment Options, Patient Selection, and Outcome Considerations for Patients With Bicuspid Aortic Valve Disease

Transcatheter aortic valve replacement has emerged as a safe and effective alternative to surgical aortic valve replacement for patients with severe symptomatic aortic stenosis across the spectrum of surgical risks based on a series of foundational randomized clinical trials. Of note, patients with bicuspid aortic valve (BAV) disease were excluded from all these pivotal randomized trials, leaving a significant knowledge gap because BAVs are commonly encountered in patients referred for aortic valve surgery or intervention. In this comprehensive review, we aim to provide heart teams with a detailed insight into how to approach patients with BAV disease, focusing on imaging and characterization of bicuspid valves, an overview of surgical approaches, and an understanding of the current data behind the role of transcatheter aortic valve replacement for patients with BAV disease.

Cellular Senescence, Aging and Non-Aging Processes in Calcified Aortic Valve Stenosis: From Bench-Side to Bedside

Aortic valve stenosis (AS) is the most common valvular heart disease. The incidence of AS increases with age, however, a significant proportion of elderly people have no significant AS, indicating that both aging and nonaging pathways are involved in the pathomechanism of AS. Age-related and stress-induced cellular senescence accompanied by further active processes represent the key elements of AS pathomechanism. The early stage of aortic valve degeneration involves dysfunction and disruption of the valvular endothelium due to cellular senescence and mechanical stress on blood flow. These cells are replaced by circulating progenitor cells, but in an age-dependent decelerating manner. When endothelial denudation is no longer replaced by progenitor cells, the path opens for focal lipid deposition, initiating subsequent oxidation, inflammation and micromineralisation. Later stages of AS feature a complex active process with extracellular matrix remodeling, fibrosis and calcification. Echocardiography is the gold standard method for diagnosing aortic valve disease, although computed tomography and cardiac magnetic resonance are useful additional imaging methods. To date, no medical treatment has been proven to halt the progression of AS. Elucidation of differences and similarities between vascular and valvular calcification pathomechanisms may help to find effective medical therapy and reduce the increasing health burden of the disease.

Managing tricuspid valve pathology in multiple valvular heart disease

Introduction

Multiple valvular heart disease (MVD) is a general term to describe regurgitant and stenotic combination involving the same valve and/or occurring in ≥2 cardiac valves. Limited data and paucity in guidelines render the diagnosis and management. This article aims to provide a state-of-the-art review concerning the diagnosis and management strategies of MVD.

Case presentation

We report a 46-year-old female with worsening dyspnea and fatigue. We perform multiple echocardiography parameters. We diagnose patients with the stenotic mitral valve, stenotic-regurgitant aortic valve, and stenotic-regurgitant tricuspid valve (TV). Double mechanical valve replacement and TV commissurotomy with Kay procedure were done with excellent results.

Clinical discussion

The prevalence of MVD is 15% in those undergoing cardiac surgery; however only 1% of those who underwent triple valve surgery involve TV. The presence of TV lesion may complicate the natural history, clinical presentation, management, and outcomes. Echocardiography with valid method remains an important tool in assessment of patients with MVD. Multidiscipline heart team discussion is essential in determining individual risk, appropriate management methods, and long-term survival.

Conclusion

The expertise of multidisciplinary heart valve team is of utmost importance in determining diagnosis and optimal management strategy.

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Multivalvular heart disease (MVD) is a complicated condition. A regurgitant and stenotic combination involves the same valve and/or occurs in ≥2 cardiac valves in MVD cases.

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The presence of tricuspid valve (TV) lesion may complicate the natural history, clinical presentation, management, and outcomes.

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Echocardiography is an important modality that can help to diagnose and sometimes can provide a prognosis after surgery.

Implementation of a CT-derived correction factor to refine the measurement of aortic valve area and stroke volume using Doppler echocardiography improves grading of severity and prediction of prognosis in patients with severe aortic stenosis

AIMS

To assess rates of reclassification of severity and associated 5-year survival in patients with severe aortic stenosis (AS) and preserved left ventricular ejection fraction (LVEF) after application of a CT-derived correction factor (CF) to refine the measurement of aortic valve area (AVA) and stroke volume index (SVi) using Doppler echocardiography.

METHODS AND RESULTS

We enrolled 1450 patients with severe AS and preserved LVEF from a French registry. Multiplication of echocardiographic LV outflow tract diameter by a CT-derived CF of 1.13 to calculate the AVA and SVi using the continuity equation resulted in reclassification of 39% of patients from severe to moderate AS (AVA > 1 cm²) and 77% from low flow (LF, SVi < 35 ml/m²) to normal flow (NF, SVi ≥ 35 ml/m²). After application of the CF, 5-year survival with conservative management was 50 ± 4% for severe AS compared to 62 ± 4% for moderate AS (p < 0.001). A strategy of medical management followed by intervention for severe AS was associated with higher risk of mortality over 5-year follow-up after adjustment for covariates and application of the CF (HR 1.35 [1.10-1.55], p = 0.015). Five-year survival was also poorer in patients remaining in the LF group after application of the CF, even after valve intervention (72%, 66% and 47% for NF to NF, LF to NF and LF to LF, respectively). After adjustment for covariates (including intervention), risk of mortality was higher in LF to LF patients compared to NF to NF (HR 1.78 [1.25-2.56]), but similar for NF to NF and LF to NF (HR 1.20 [0.90-1.60]).

CONCLUSION

Refined accuracy of echocardiographic LV outflow tract diameter measurement using a CF of 1.13 before derivation of AVA and SVi in patients with severe AS and preserved LVEF allows improved grading of severity, and prediction of prognosis. We recommend implementation of the CF during routine echocardiography when using the continuity equation for Doppler haemodynamic measurements.

Classification of severe aortic stenosis and outcomes after aortic valve replacement

Aortic valve calcium scoring by cardiac computed tomographic (CT) has been recommended as an alternative to classify the AS (aortic stenosis) severity, but it is unclear that whether CT findings would have additional value to discriminate significant AS subtypes including high gradient severe AS, classic low-flow, low gradient (LF-LG) AS, paradoxical LF-LG AS, and moderate AS. In this study, we examined the preoperative clinical and cardiac CT findings of different subtypes of AS in patients with surgical aortic valve replacement (AVR) and evaluated the subtype classification as a factor affecting post-surgical outcomes. This study included 511 (66.9 ± 8.8 years, 55% men) consecutive patients with severe AS who underwent surgical AVR. Aortic valve area (AVA) was obtained by echocardiography (AVA_echo) and by CT (AVA_CT) using each modalities measurement of the left ventricular outflow tract. Patients with AS were classified as (1) high-gradient severe (n = 438), (2) classic LF-LG (n = 18), and (3) paradoxical LF-LG (n = 55) based on echocardiography. In all patients, 455 (89.0%) patients were categorized as severe AS according to the AVA_CT. However, 56 patients were re-classified as moderate AS (43 [9.8%] high-gradient severe AS, 5 [27.8%] classic LF-LG AS, and 8 [14.5%] paradoxical LF-LG AS) by AVA_CT. The classic LF-LG AS group presented larger AVA_CT and aortic annulus than those in high-gradient severe AS group and one third of them had AVA_CT ≥ 1.2 cm². After multivariable adjustment, old age (hazard ratio [HR], 1.04, P = 0.049), high B-type natriuretic peptide (BNP) (HR, 1.005; P < 0.001), preoperative atrial fibrillation (HR, 2.75; P = 0.003), classic LF-LG AS (HR, 5.53, P = 0.004), and small aortic annulus on CT (HR, 0.57; P = 0.002) were independently associated with major adverse cardiac and cerebrovascular events (MACCE) after surgical AVR.

Cardiac Computed Tomography: Application in Valvular Heart Disease

The incidence and prevalence of valvular heart disease (VHD) is increasing and has been described as the next cardiac epidemic. Advances in imaging and therapeutics have revolutionized how we assess and treat patients with VHD. Although echocardiography continues to be the first-line imaging modality to assess the severity and the effects of VHD, advances in cardiac computed tomography (CT) now provide novel insights into VHD. Transcatheter valvular interventions rely heavily on CT guidance for procedural planning, predicting and detecting complications, and monitoring prosthesis. This review focuses on the current role and future prospects of CT in the assessment of aortic and mitral valves for transcatheter interventions, prosthetic valve complications such as thrombosis and endocarditis, and assessment of the myocardium.

Imaging Challenges in Patients with Severe Aortic Stenosis and Heart Failure: Did We Find a Way Out of the Labyrinth?

Aortic stenosis (AS) is the most frequent degenerative valvular disease in developed countries. Its incidence has been constantly rising due to population aging. The diagnosis of AS was considered straightforward for a very long time. High gradients and reduced aortic valve area were considered as "sine qua non" in diagnosis of AS until a growing body of evidence showed that patients with low gradients could also have severe AS with the same or even worse outcome. This completely changed the paradigm of AS diagnosis and involved large numbers of parameters that had never been used in the evaluation of AS severity. Low gradient AS patients may present with heart failure (HF) with preserved or reduced left ventricular ejection fraction (LVEF), associated with changes in cardiac output and flow across the aortic valve. These patients with low-flow low-gradient or paradoxical low-flow low-gradient AS are particularly challenging to diagnose, and cardiac output and flow across the aortic valve have become the most relevant parameters in evaluation of AS, besides gradients and aortic valve area. The introduction of other imaging modalities in the diagnosis of AS significantly improved our knowledge about cardiac mechanics, tissue characterization of myocardium, calcium and inflammation burden of the aortic valve, and their impact on severity, progression and prognosis of AS, not only in symptomatic but also in asymptomatic patients. However, a variety of novel parameters also brought uncertainty regarding the clinical relevance of these indices, as well as the necessity for their validation in everyday practice. The aim of this review is to summarize the prevalence of HF in patients with severe AS and elaborate on the diagnostic challenges and advantages of comprehensive multimodality cardiac imaging to identify the patients that may benefit from surgical or transcatheter aortic valve replacement, as well as parameters that may help during follow-up.

Orifice areas of balloon-expandable transcatheter heart valves: a three-dimensional transesophageal echocardiography study

INTRODUCTION

Accurate expected effective orifice area (EOA) values for balloon-expandable (BE) transcatheter heart valves (THV) are crucial for preventing patient prosthesis mismatch (PPM) and assessment of THV function. Currently published reference EOAs, however, are based on transthoracic echocardiography (TTE) which may be subject to left ventricular outflow tract diameter underestimation and/or suboptimal THV Doppler interrogation. The objective of this study was to establish reference EOA values for BE THVs based on Doppler and three-dimensional (3D) transesophageal echocardiography (TEE).

METHODS

We retrospectively reviewed 212 intra-procedural TEEs performed during BE THV implantation with optimal post-implant Doppler and 3D imaging. We compared continuity equation-derived EOAs to geometric orifice areas by 3D-planimetry (GOA_3D). Performance indices (i.e., EOA normalized to valve size) and PPM rates were determined. TTE-based EOAs performed within 30 days were also calculated in a subset of 170 patients.

RESULTS

The average EOA for all BE THV valves (77% Sapien 3) was 2.3 cm² ± 0.5, while the average EOA was 1.6 ± 0.2 cm² for 20 mm, 2.0 ± 0.2 cm² for 23 mm, 2.5 ± 0.3 cm² for 26 mm and 3.0 ± 0.3 cm² for 29 mm THV size (p<0.001). Bland-Altman analysis demonstrated very good agreement between EOA and GOA_3D (bias -0.04 ± 0.15 cm²). There was a strong correlation between annular area and TEE-based EOA (R=0.84) and GOA_3D (R=0.87). The mean performance index was 47 ± 5% and was similar for all THV sizes (p=0.21). EOAs based on TTE were smaller compared to TEE, while the correlation with annular area (R=0.67) and agreement with GOA_3D (bias -0.26 ± 0.43 cm²) was not as strong. The overall PPM rate was 2% in the TEE cohort and 12% in the TTE cohort.

CONCLUSIONS

Effective orifice areas for BE THVs based on intra-procedural Doppler and 3D-TEE suggest that previously published TTE-based reference values for EOA are underestimated while PPM rates may be overestimated. Our findings have important clinical implications for pre-implant decision making and for the evaluation of THV hemodynamics and function during follow-up.

Baseline PA/BSA ratio in patients undergoing transcatheter aortic valve replacement - A novel CT-based marker for the prediction of pulmonary hypertension and outcome

BACKGROUND

Pulmonary hypertension (pH) has a prognostic impact on patients undergoing transcatheter aortic valve replacement (TAVR). Pulmonary artery (PA) dilatation assessed by multidetector computed tomography (MDCT) has the potential to predict PH. The aim of the study was to evaluate the clinical parameters associated with PA dilatation and to investigate its prognostic relevance in patients undergoing TAVR.

METHODS

In 770 patients undergoing TAVR between February 2016 and July 2019, PA diameter was measured by MDCT before TAVR. Additionally, PA diameter divided by ascending aorta diameter or body surface area (BSA) was calculated.

RESULTS

Of all the CT-derived parameters compared with a receiver operating characteristic curve, the value for PA/BSA with a median of 1.68 (IQR 1.47, 1.91) cm/m2 showed the greatest area-under-the-curve (0.75) for predicting PH at baseline. Based on this median, patients were assigned to a small PA/BSA (n = 386) or a large PA/BSA (n = 384) group. Hereby, a large PA/BSA was independently associated with PH at baseline (OR:8.39 [5.36-13.14], p < 0.001) and after TAVR (OR:1.73 [1.18-2.53], p = 0.005). A large PA/BSA was associated with a significantly higher cumulative two-year all-cause mortality compared to small PA/BSA (30.0% vs. 13.7%, p < 0.001), which was supported in the multivariable model (HR:1.87; 95%CI, 1.12-3.04; p = 0.017).

CONCLUSION

Patients with a large PA/BSA on MDCT are more likely to have PH at baseline and after TAVR. Large PA/BSA is associated with an increased risk of mortality and could provide additional information for risk stratification in patients undergoing TAVR.

Mixed-Valve Disease: Management of Patients with Aortic Stenosis and Mitral Regurgitation: Thresholds for Surgery Versus Percutaneous Therapies

Significant mitral regurgitation (MR), frequently seen in the presence of severe aortic stenosis (AS), results in an association that negatively affects prognosis and imposes particular challenges for both the assessment of the severity of valvular lesions and decisions regarding treatment allocation. This article reviews the available literature with regards to the assessment of MR and AS in the presence of both; surgical management and results in patients with concomitant AS and MR; the effect of MR on outcomes in patients undergoing transcatheter aortic valve replacement; the effect of transcatheter aortic valve replacement on MR severity; and percutaneous treatment for MR after transcatheter aortic valve implantation. The authors aim to provide assistance in the decision-making process to treat patients with either a higher-risk double-valve procedure or a simpler, but perhaps incomplete, single-valve option.

Application of the proximal isovelocity surface area method for estimation of the effective orifice area in aortic stenosis

Although the echocardiographic effective orifice area (EOA) calculated using the continuity equation is widely used for the assessment of severity in aortic stenosis (AS), the existence of high flow velocity at the left ventricular outflow tract (LVOT) potentially causes its overestimation. The proximal isovelocity surface area (PISA) method could be an alternative tool for the estimation of EOA that limits the influence of upstream flow velocity. EOA was calculated using the continuity equation (EOA_Cont) and PISA method (EOA_PISA), respectively, in 114 patients with at least moderate AS. The geometric orifice area (GOA) was also measured using the planimetry method in 51 patients who also underwent three-dimensional transesophageal echocardiography. Patients were divided into two groups according to the median LVOT flow velocity. EOA_PISA could be obtained in 108 of the 114 patients (95%). Although there was a strong correlation between EOA_Cont and EOA_PISA (r = 0.78, P < 0.001), EOA_Cont was statistically significantly larger than EOA_PISA (0.86 ± 0.33 vs 0.75 ± 0.29 cm², P < 0.001). Both EOA_Cont and EOA_PISA similarly correlated with GOA (r = 0.70, P < 0.001 and r = 0.77, P < 0.001, respectively). However, a fixed bias, which is hydrodynamically supposed to exist between EOA and GOA, was not observed between EOA_Cont and GOA. In contrast, there was a negative fixed bias between EOA_PISA and GOA with smaller EOA_PISA than GOA. The difference between EOA_Cont and GOA was significantly greater with a larger EOA_Cont relative to GOA in patients with high LVOT flow velocity than in those without (0.16 ± 0.25 vs - 0.07 ± 0.10 cm², P < 0.001). In contrast, the difference between EOA_PISA and GOA was consistent regardless of the LVOT flow velocity (- 0.07 ± 0.12 vs - 0.07 ± 0.15 cm², P = 0.936). The PISA method was applied to estimate EOA in patients with AS. EOA_PISA could be an alternative parameter for AS severity grading in patients with high LVOT flow velocity in whom EOA_Cont would potentially overestimate the orifice area.

Size-adjusted aortic valve area: refining the definition of severe aortic stenosis

AIMS

Severe aortic valve stenosis (AS) is defined by an aortic valve area (AVA) <1 cm2 or an AVA indexed to body surface area (BSA) <0.6 cm/m2, despite little evidence supporting the latter approach and important intrinsic limitations of BSA indexation. We hypothesized that AVA indexed to height (H) might be more applicable to a wide range of populations and body morphologies and might provide a better predictive accuracy.

METHODS AND RESULTS

In 1298 patients with degenerative AS and preserved ejection fraction from three different countries and continents (derivation cohort), we aimed to establish an AVA/H threshold that would be equivalent to 1.0 cm2 for defining severe AS. In a distinct prospective validation cohort of 395 patients, we compared the predictive accuracy of AVA/BSA and AVA/H. Correlations between AVA and AVA/BSA or AVA/H were excellent (all R2 > 0.79) but greater with AVA/H. Regressions lines were markedly different in obese and non-obese patients with AVA/BSA (P < 0.0001) but almost identical with AVA/H (P = 0.16). AVA/BSA values that corresponded to an AVA of 1.0 cm2 were markedly different in obese and non-obese patients (0.48 and 0.59 cm2/m2) but not with AVA/H (0.61 cm2/m for both). Agreement for the diagnosis of severe AS (AVA < 1 cm2) was significantly higher with AVA/H than with AVA/BSA (P < 0.05). Similar results were observed across the three countries. An AVA/H cut-off value of 0.6 cm2/m [HR = 8.2(5.6-12.1)] provided the best predictive value for the occurrence of AS-related events [absolute AVA of 1 cm2: HR = 7.3(5.0-10.7); AVA/BSA of 0.6 cm2/m2 HR = 6.7(4.4-10.0)].

CONCLUSION

In a large multinational/multiracial cohort, AVA/H was better correlated with AVA than AVA/BSA and a cut-off value of 0.6 cm2/m provided a better diagnostic and prognostic value than 0.6 cm2/m2. Our results suggest that severe AS should be defined as an AVA < 1 cm2 or an AVA/H < 0.6 cm2/m rather than a BSA-indexed value of 0.6 cm2/m2.

Sex differences in aortic valve calcification in severe aortic valve stenosis: association between computer tomography assessed calcification and valvular calcium concentrations

AIMS

The aims of this study were to investigate the correlation and sex differences between total valve calcium, valve calcium concentration, and aortic valve calcification (AVC) in explanted valves from patients with severe aortic valve stenosis undergoing aortic valve replacement (AVR).

METHODS AND RESULTS

Sixty-nine patients with severe aortic stenosis (AS) scheduled for elective AVR underwent echocardiography and cardiac computed tomography (CT) prior to surgery (AVCin vivo) and CT of the explanted aortic valve (AVCex vivo). Explanted valves were prepared in acid solution, sonicated, and analysed with Arsenazo III dye to estimate total valve calcium and valve calcium concentration. Median AVCex vivo was 2082 (1421-2973) AU; mean valve calcium concentration was 1.43 ± 0.42 µmol Ca2+/mg tissue; median total valve calcium 156 (111-255) mg Ca2+, and valve calcium density 52 (35-81) mg/cm2. AVC displayed a strong correlation with total valve calcium (R2 = 0.98, P < 0.001) and a moderate correlation with valve calcium concentration (R2 = 0.62, P < 0.001). Valvular calcium concentration was associated with sex, aortic valve area, and mean gradient. After adjusting for age and estimated glomerular filtration rate, sex and mean gradient remained associated with valve calcium concentrations.

CONCLUSION

AVC score provides a strong estimate for total valve calcium but to a lesser degree calcium concentration in the valve tissue of patients with severe AS. Females presented lower valvular calcium concentrations than males irrespective of AS severity, adding evidence and providing support to the important point that sex differences in valvular calcium concentration in AS does not reflect valvular size.

Advanced cardiovascular multimodal imaging and aortic stenosis

Aortic valve stenosis has become the most common valvular heart disease on account of aging population and increasing life expectancy. Echocardiography is the primary diagnosis tool for this, but it still has many flaws. Therefore, advanced cardiovascular multimodal imaging techniques are continuously being developed in order to overcome these limitations. Cardiac magnetic resonance imaging (CMR) allows a comprehensive morphological and functional evaluation of the aortic valve and provides important data for the diagnosis and risk stratification in patients with aortic stenosis. CMR can functionally assess the aortic flow using two-dimensional and time-resolved three-dimensional velocity-encoded phase-contrast techniques. Furthermore, by late gadolinium enhancement and T1-mapping, CMR can reveal the presence of both irreversible replacement and diffuse interstitial myocardial fibrosis. Moreover, its role in guiding aortic valve replacement procedures is beginning to take shape. Recent studies have rendered the importance of active and passive biomechanics in risk stratification and prognosis prediction in patients with aortic stenosis, but more work is required is just in its infancy, but data are promising. In addition, cardiac computed tomography is particularly useful for the diagnosis of aortic valve stenosis, and in preprocedural evaluation of the aorta, while positron emission tomography can be also used to assess valvular inflammation and active calcification. The purpose of this review is to provide a comprehensive overview of current available data regarding advanced cardiovascular multimodal imaging in aortic stenosis.

Multimodality imaging in valvular heart disease: how to use state-of-the-art technology in daily practice

Our understanding of the complexities of valvular heart disease (VHD) has evolved in recent years, primarily because of the increased use of multimodality imaging (MMI). Whilst echocardiography remains the primary imaging technique, the contemporary evaluation of patients with VHD requires comprehensive analysis of the mechanism of valvular dysfunction, accurate quantification of severity, and active exclusion extravalvular consequences. Furthermore, advances in surgical and percutaneous therapies have driven the need for meticulous multimodality imaging to aid in patient and procedural selection. Fundamental decision-making regarding whom, when, and how to treat patients with VHD has become more complex. There has been rapid technological advancement in MMI; many techniques are now available in routine clinical practice, and their integration into has the potential to truly individualize management strategies. This review provides an overview of the current evidence for the use of MMI in VHD, and how various techniques within each modality can be used practically to answer clinical conundrums.

Indirect ultrasound evaluation of left ventricular outflow tract diameter implications for heart failure and aortic stenosis severity assessment

BACKGROUND

Whereas dependency of left ventricular outflow tract diameter (LVOTD) from body surface area (BSA) has been established and a BSA-based LVOTD formula has been derived, the relationship between LVOTD and aortic root and LV dimensions has never been explored. This may have implications for evaluation of LV output in heart failure (HF) and aortic stenosis (AS) severity.

METHODS

A cohort of 540 HF patients who underwent transthoracic echocardiography was divided in a derivation and validation subgroup. In the derivation subgroup (N = 340), independent determinants of LVOTD were analyzed to derive a regression equation, which was used for predicting LVOTD in the validation subgroup (N = 200) and compared with the BSA-derived formula.

RESULTS

LVOTD determinants in the derivation subgroup were sinuses of Valsalva diameter (SVD, beta = 0.392, P < .001), BSA (beta = 0.229, P < .001), LV end-diastolic diameter (LVEDD, beta = 0.145, P = .001), and height (beta = 0.125, P = .037). The regression equation for predicting LVOTD with the aforementioned variables (LVOTD = 6.209 + [0.201 × SVD] + [1.802 × BSA] + [0.03 × LVEDD] + [0.025 × Height]) did not differ from (P = .937) and was highly correlated with measured LVOTD (R = 0.739, P < .001) in the validation group. Repeated analysis with LV end-diastolic volume instead of LVEDD and/or accounting for gender showed similar results, whereas BSA-derived LVOTD values were different from measured LVOTD (P < .001).

CONCLUSION

Aortic root and LV dimensions affect LVOTD independently from anthropometric data and are included in a new comprehensive equation for predicting LVOTD. This should improve evaluation of LV output in HF and severity of AS when direct LVOTD measurement is difficult or impossible.

Evaluation and Management of Aortic Stenosis in Chronic Kidney Disease: A Scientific Statement From the American Heart Association

Aortic stenosis with concomitant chronic kidney disease (CKD) represents a clinical challenge. Aortic stenosis is more prevalent and progresses more rapidly and unpredictably in CKD, and the presence of CKD is associated with worse short-term and long-term outcomes after aortic valve replacement. Because patients with advanced CKD and end-stage kidney disease have been excluded from randomized trials, clinicians need to make complex management decisions in this population that are based on retrospective and observational evidence. This statement summarizes the epidemiological and pathophysiological characteristics of aortic stenosis in the context of CKD, evaluates the nuances and prognostic information provided by noninvasive cardiovascular imaging with echocardiography and advanced imaging techniques, and outlines the special risks in this population. Furthermore, this statement provides a critical review of the existing literature pertaining to clinical outcomes of surgical versus transcatheter aortic valve replacement in this high-risk population to help guide clinical decision making in the choice of aortic valve replacement and specific prosthesis. Finally, this statement provides an approach to the perioperative management of these patients, with special attention to a multidisciplinary heart-kidney collaborative team-based approach.

Association between multimodality measures of aortic stenosis severity and quality-of-life improvement outcomes after transcatheter aortic valve replacement

AIMS

Up to 40% of patients with aortic stenosis (AS) present with discordant grading of AS severity based on common transthoracic echocardiography (TTE) measures. Our aim was to evaluate the utility of TTE and multi-detector computed tomography (MDCT) measures in predicting symptomatic improvement in patients with AS undergoing transcatheter aortic valve replacement (TAVR).

METHODS AND RESULTS

A retrospective review of 201 TAVR patients from January 2017 to November 2018 was performed. Pre- and post-intervention quality-of-life was measured using the Kansas City Cardiomyopathy Questionnaire (KCCQ-12). Pre-intervention measures including dimensionless index (DI), stroke volume index (SVI), mean transaortic gradient, peak transaortic velocity, indexed aortic valve area (AVA), aortic valve calcium score, and AVA based on hybrid MDCT-Doppler calculations were obtained and correlated with change in KCCQ-12 at 30-day follow-up. Among the 201 patients studied, median KCCQ-12 improved from 54.2 pre-intervention to 85.9 post-intervention. In multivariable analysis, patients with a mean gradient >40 mmHg experienced significantly greater improvement in KCCQ-12 at follow-up than those with mean gradient ≤40 mmHg (28.1 vs. 16.4, P = 0.015). Patients with MDCT-Doppler-calculated AVA of ≤1.2 cm2 had greater improvements in KCCQ-12 scores than those with computed tomography-measured AVA of >1.2 cm2 (23.4 vs. 14.1, P = 0.049) on univariate but not multivariable analysis. No association was detected between DI, SVI, peak velocity, calcium score, or AVA index and change in KCCQ-12.

CONCLUSION

Mean transaortic gradient is predictive of improvement in quality-of-life after TAVR. This measure of AS severity may warrant greater relative consideration when selecting the appropriateness of patients for TAVR.

Multimodality Imaging for Discordant Low-Gradient Aortic Stenosis: Assessing the Valve and the Myocardium

Aortic stenosis (AS) is a disease of the valve and the myocardium. A correct assessment of the valve disease severity is key to define the need for aortic valve replacement (AVR), but a better understanding of the myocardial consequences of the increased afterload is paramount to optimize the timing of the intervention. Transthoracic echocardiography remains the cornerstone of AS assessment, as it is universally available, and it allows a comprehensive structural and hemodynamic evaluation of both the aortic valve and the rest of the heart. However, it may not be sufficient as a significant proportion of patients with severe AS presents with discordant grading (i.e., an AVA ≤ 1 cm² and a mean gradient <40 mmHg) which raises uncertainty about the true severity of AS and the need for AVR. Several imaging modalities (transesophageal or stress echocardiography, computed tomography, cardiovascular magnetic resonance, positron emission tomography) exist that allow a detailed assessment of the stenotic aortic valve and the myocardial remodeling response. This review aims to provide an updated overview of these multimodality imaging techniques and seeks to highlight a practical approach to help clinical decision making in the challenging group of patients with discordant low-gradient AS.

Watchful waiting care or early intervention in asymptomatic severe aortic stenosis: Where we are

Aortic stenosis, the most common valvular heart disease in Western countries, affects predominantly older people. Prompt aortic valve replacement is undoubtedly indicated in symptomatic patients. Management of asymptomatic patients is nowadays shifting from a conservative approach to early aortic valve replacement, as multimodality imaging is increasingly available. However, multimodality imaging has led to multiple prognostic parameters and complex algorithms, as well as a new staging classification that has left patients and physicians somewhat puzzled. We highlight the value of thorough serial clinical examinations, Doppler echocardiography and exercise testing when caring for a growing aortic stenosis population, including that has no or limited access to multimodality imaging. Evidence for early aortic valve replacement versus conservative management in asymptomatic patients with severe aortic stenosis is biased by the lack of serial stress testing evaluation; 30% of so-called asymptomatic patients were in fact symptomatic, and thus were clear candidates for aortic valve replacement in the above-mentioned studies. Randomized trials of aortic valve replacement versus conservative management that include serial stress testing evaluation are needed to ascertain whether early aortic valve replacement actually improves clinical outcome in asymptomatic patients with severe aortic stenosis. Less interventional medicine and healthcare resource utilization can result in better health.

The Left Ventricular Outflow Tract Changes in Size and Shape From Pre- to Post-Cardiopulmonary Bypass: Three-Dimensional Transesophageal Echocardiography

OBJECTIVES

To compare two-dimensional (2D) and 3D imaging of the left ventricular outflow tract (LVOT) and to evaluate geometric changes pre- to post-cardiopulmonary bypass (CPB).

DESIGN

Retrospective review of intraoperative transesophageal echocardiographic examinations.

SETTING

Single academic medical center.

PARTICIPANTS

The study comprised 69 cardiac surgical patients-27 with aortic valve stenosis (AS) and 42 without AS.

INTERVENTIONS

Two-dimensional and 3D analysis of the LVOT pre- and post-CPB.

MEASUREMENTS AND MAIN RESULTS

Pre- and post-CPB 2D assessment of LVOT diameter (2D LVOTd) was compared with 3D analysis of the minor (3D LVOTd-min) and major diameters. LVOT areas (LVOTa) were calculated using LVOTd to yield 2D LVOTa and 3D LVOTa-min. These were compared with LVOTa measured by planimetry (3D LVOTa-plan). An ellipticity ratio (ER) (ER = 3D minor/major axes) was calculated. The 2D LVOTd was larger than the 3D LVOTd-min before (2.12 v 2.02 cm respectively (resp); p < 0.001) and after (1.96 v 1.85 cm resp; p = 0.04) CPB. Compared with pre-CPB, there were significant decreases in the 2D LVOTd (p = 0.003) and the 3D LVOTd-min (p < 0.001) post-CPB. Ellipticity increased after CPB (ER 0.80 v 0.75; p = 0.004), and the 2D LVOTa was larger than the 3D LVOTa-min before CPB (3.60 cm²v 3.28 cm²; p < 0.001) and less so after CPB (3.11 cm²v 2.79 cm²; p = 0.053). Compared with pre-CPB, all LVOTa measurements decreased significantly after CPB (p < 0.001). The 3D LVOTa-plan decreased after CPB by approximately 10% (4.05 cm²v 3.61 cm²; p < 0.001). The 2D LVOTa and 3D LVOTa-min underestimated the 3D LVOTa-plan before and after CPB (p < 0.001) by 11% to 14% and 19% to 23%, respectively. When compared with non-AS patients, patients with AS had a smaller LVOTa pre- and post-CPB (p < 0.05).

CONCLUSIONS

The LVOT is smaller and more elliptical after CPB. Patients with AS have a smaller LVOT compared with non-AS patients. LVOTa calculated using LVOTd underestimates the 3D LVOTa-plan by as much as 23% depending on patient type and timing of measurement. Accurate assessment of the LVOT requires 3D imaging.

Reclassification of aortic stenosis by fusion of echocardiography and computed tomography in low-gradient aortic stenosis

Background

The integration of computed tomography (CT)-derived left ventricular outflow tract area into the echocardiography-derived continuity equation results in the reclassification of a significant proportion of patients with severe aortic stenosis (AS) into moderate AS based on aortic valve area indexed to body surface area determined by fusion imaging (fusion AVA_i). The aim of this study was to evaluate AS severity by a fusion imaging technique in patients with low-gradient AS and to compare the clinical impact of reclassified moderate AS versus severe AS.

Methods

We included 359 consecutive patients who underwent transcatheter aortic valve implantation for low-gradient, severe AS at two academic institutions and created a joint database. The primary endpoint was a composite of all-cause mortality and rehospitalisations for heart failure at 1 year.

Results

Overall, 35% of the population (n = 126) were reclassified to moderate AS [median fusion AVAi 0.70 (interquartile range, IQR 0.65–0.80) cm²/m²] and severe AS was retained as the classification in 65% [median fusion AVAi 0.49 (IQR 0.43–0.54) cm²/m²]. Lower body mass index, higher logistic EuroSCORE and larger aortic dimensions characterised patients reclassified to moderate AS. Overall, 57% of patients had a left ventricular ejection fraction (LVEF) <50%. Clinical outcome was similar in patients with reclassified moderate or severe AS. Among patients reclassified to moderate AS, non-cardiac mortality was higher in those with LVEF <50% than in those with LVEF ≥50% (log-rank p = 0.029).

Conclusions

The integration of CT and transthoracic echocardiography to obtain fusion AVAi led to the reclassification of one third of patients with low-gradient AS to moderate AS. Reclassification did not affect clinical outcome, although patients reclassified to moderate AS with a LVEF <50% had worse outcomes owing to excess non-cardiac mortality.

[Aortic stenosis-which diagnostic algorithms and which treatment?]

The progress in cardiology during the last 50 years can best be studied by looking at the diagnostics and treatment of patients with aortic valve stenosis. Previously, the clinical examination, electrocardiography (ECG) and chest X‑ray were used before heart catheterization, which included a transseptal puncture to complete the indications for surgery in young patients. Nowadays, echocardiography, often combined with a dobutamine stress test, is the primary diagnostic tool to which computed tomography for quantification of valve calcification and cardiac magnetic resonance imaging can be of additive value. The treatment of severe aortic valve stenosis is no longer only treated by aortic valve replacement but transluminal aortic valve implantation also represents a new therapeutic option. The change in the age groups of treated patients is also noteworthy. Surgery is recommended for patients under 75 years old but for older patients, especially those with a high risk, interventional catheter-assisted treatment is preferred.