Left and Right Ventricular Longitudinal Systolic Function Following Aortic Valve Replacement in the PARTNER 2 Trial And Registry.

AIMS: Evaluation of left and right ventricular longitudinal systolic function may enhance risk stratification following aortic valve replacement (AVR). The study objective was to evaluate the changes in left and right ventricular longitudinal systolic function and RV-pulmonary artery (RV-PA) coupling from baseline to 30-days and 1-year after aortic valve replacement (AVR). METHODS AND RESULTS: LV longitudinal strain (LS), tricuspid annulus plane systolic excursion (TAPSE), and RV-PA coupling were evaluated in patients from the PARTNER-2A surgical AVR (SAVR) arm (n=985) and from the PARTNER-2 SAPIEN-3 registry (n=719). TAPSE and RV-PA coupling decreased significantly following SAVR, but remained stable following TAVR. Lower LV LS, TAPSE, or RV-PA coupling at baseline were associated with increased risk of the composite of death, hospitalization, and stroke at 5-years (Adjusted-HRs for LV LS<15%: 1.24 95%CI 1.05-1.45, p=0.001; TAPSE<14mm: 1.44 95%CI 1.21-1.73, p<0.001; RV/PA coupling<0.55mm/mmHg: 1.32 95% CI 1.07-1.63, p=0.011). Reduced TAPSE at baseline was the most powerful predictor of the composite endpoint at 5-years. Patients with LV ejection fraction <50% at baseline had increased risk of the primary endpoint with SAVR (HR: 1.34, 95%CI 1.08-1.68, p=0.009) but not with TAVR (HR: 1.12, 95%CI 0.88-1.42). Lower RV-PA coupling at 30-days showed the strongest association with cardiac mortality. CONCLUSION: SAVR but not TAVR was associated with a marked deterioration in RV longitudinal systolic function and RV-PA coupling. Lower TAPSE and RV-PA coupling at 30-days were associated with inferior clinical outcomes at 5-years. In patients with LVEF<50%, TAVR was associated with superior 5-year outcomes.

Effect of race on pressure recovery adjustment for prevention of aortic stenosis grading discordance.

OBJECTIVE: We sought to evaluate the potential impact of racial difference (Asians vs Caucasians) on the clinical usefulness of pressure recovery (PR) adjustment for preventing discordant aortic stenosis (AS) grading in patients with severe AS. METHODS: Data from 1450 patients (mean age, 70.2±10.6 years; 290 (20%) Caucasians; aortic valve area (AVA), 0.77±0.26 cm2) were retrospectively analysed. PR-adjusted AVA was calculated using a validated equation. Discordant grading of severe AS was defined as AVA of <1.0 cm2 and mean gradient of <40 mm Hg. The frequency of discordant grading was assessed in the overall cohort and the propensity score-matched cohort. RESULTS: Before PR adjustment, 1186 patients showed AVA values of <1.0 cm2; after PR adjustment, 170 (14.3%) were reclassified as having moderate AS. PR adjustment decreased the frequency of discordant grading from 31.4% to 14.1% in Caucasians and from 13.8% to 7.9% in Asians. Patients with reclassification to moderate AS after PR adjustment had a significantly lower risk of a composite of aortic valve replacement or all-cause death than did those with severe AS after PR adjustment (HR 0.38; 95% CI 0.31-0.46; p<0.001). In propensity score-matched cohorts (173 pairs), the frequency of discordant grading before PR adjustment was 42.2% and 43.9% in the Caucasian and Asian patients, respectively, which decreased to 21.4% and 20.2%, respectively, after PR adjustment. CONCLUSIONS: Clinically relevant PR occurred, regardless of race in patients with moderate to severe AS. Routine PR adjustment may be useful for reconciling discordant AS grading.

Sex-specific correlates of valvular and arterial calcification burden in patients with moderate aortic stenosis.

INTRODUCTION: There are significant sex differences in the prevalence and severity of cardiac calcifying processes. Women harbour more severe mitral annular calcification (MAC), while men exhibit worse aortic valve (AVC) and coronary artery (CAC) calcification. To better understand these differences, we investigated the correlates of cardiac calcification according to sex. METHODS: We conducted a cross-sectional study of 406 patients with ≥mild aortic stenosis (AS) defined by an aortic valve area ≤1.5 cm2, a peak aortic jet velocity >2.0 m/s, or a mean transvalvular gradient >15 mm Hg. Doppler-echocardiography and non-contrast multidetector CT were performed concomitantly to assess AS and cardiac calcifications. RESULTS: Mean age was 71±11 years and 33% were women. The AS haemodynamics were not significantly different between sexes (all p>0.50), with a mean indexed aortic valve area of 0.59±0.21 cm2/m2, peak aortic jet velocity of 2.78 (2.37-3.68) m/s, and mean gradient of 17.9 (12.8-31.3) mm Hg for the whole cohort. Compared with men, women harboured lower AVC (480 (222-1191) vs 1003 (484-2329) Agatston unit, AU; p<0.0001) and CAC (366 (50-914) vs 618 (167-1357) AU; p=0.007), but more severe MAC (60 (1-887) vs 48 (0-351) AU; p=0.08) and ascending aorta calcification (227 (43-863) vs 142 (7-493) AU; p=0.03). After comprehensive adjustment, sex remained an independent predictor of each cardiac calcification subtype (all p<0.02) except for the ascending aorta (p=0.32). In multivariable analysis, certain variables, like age or bicuspid aortic valve, were associated with the calcification scores in both sexes. Sex-specific predictors of calcification burden were absence of angiotensin receptor blockers (ß=-0.26; p=0.007) and renal impairment (ß=0.26; p=0.003) for AVC, and bisphosphonates (ß=0.20; p=0.05) for CAC in women; coronary artery disease (ß=0.25; p=0.001) for AVC, and angiotensin receptor blockers (ß=0.19; p=0.02) and calcium/vitamin D (ß=0.15; p=0.02) for MAC in men. CONCLUSION: In AS, factors associated with cardiac valvular and arterial calcification differ between sexes, suggesting an important contributory role of sex in the pathophysiology of these calcifying processes.

Validation of aortic valve calcium quantification thresholds measured by computed tomography in Asian patients with calcific aortic stenosis.

AIMS: Sex-specific thresholds of aortic valve calcification (AVC) have been proposed and validated in Caucasians. Thus, we aimed to validate their accuracy in Asians. METHODS AND RESULTS: Patients with calcific aortic stenosis (AS) from seven international centres were included. Exclusion criteria were ≥moderate aortic/mitral regurgitation and bicuspid valve. Optimal AVC and AVC-density sex-specific thresholds for severe AS were obtained in concordant grading and normal flow patients (CG/NF). We included 1263 patients [728 (57%) Asians, 573 (45%) women, 837 (66%) with CG/NF]. Mean gradient was 48 (26-64) mmHg and peak aortic velocity 4.5 (3.4-5.1) m/s. Optimal AVC thresholds were: 2145 Agatston Units (AU) in men and 1301 AU in women for Asians; and 1885 AU in men and 1129 AU in women for Caucasians. Overall, accuracy (% correctly classified) was high and comparable either using optimal or guidelines' thresholds (2000 AU in men, 1200 AU in women). However, accuracy was lower in Asian women vs. Caucasian women (76-78% vs. 94-95%; P < 0.001). Accuracy of AVC-density (476 AU/cm2 in men and 292 AU/cm2 in women) was comparable to absolute AVC in Caucasians (91% vs. 91%, respectively, P = 0.74), but higher than absolute AVC in Asians (87% vs. 81%, P < 0.001). There was no interaction between AVC/AVC-density and ethnicity (all P > 0.41) with regards to AS haemodynamic severity. CONCLUSION: AVC thresholds defining severe AS are comparable in Asian and Caucasian populations, and similar to those proposed in the guidelines. However, accuracy of AVC to identify severe AS in Asians (especially women) is sub-optimal. Therefore, the use of AVC-density is preferable in Asians.

Computed Tomography Aortic Valve Calcium Scoring in Patients With Bicuspid Aortic Valve Stenosis.

Background: Sex-specific thresholds of computed tomography (CT)-derived aortic valve calcification (AVC) or AVC density (AVCd) to identify severe aortic stenosis (AS) have been established in populations that consisted mainly of Caucasians with a tricuspid aortic valve. The objective of this study was to evaluate the accuracy (i.e., sensitivity and specificity) of previously established thresholds to identify severe AS in patients with bicuspid aortic valve (BAV) and according to ethnicity: Caucasian vs. Asian. Methods: We built a multicenter registry of echocardiographic and CT data collected in BAV patients with at least mild AS and preserved left ventricular ejection fraction from 7 different centers. Anatomic severity of AS obtained by CT-derived AVC and AVCd was compared to hemodynamic severity of AS obtained by echocardiography. Results: Among 485 BAV patients (60% men, 73% Asians), the best thresholds of AVC and AVCd to identify severe AS in BAV patients were 2315 arbitrary units (AU) (sensitivity [Se]/specificity [Spe] = 82/78%) in men, 1103 AU (Se/Spe = 80/82%) in women, and 561 AU/cm2 (Se/Spe = 86/91%) in men, and 301 AU/cm2 (Se/Spe = 83/82%) in women, respectively. According to ethnicity, thresholds for severe AS in Caucasian patients were, respectively, in men and women: 2208 AU (Se/Spe = 83/83%) and 1230 AU (Se/Spe = 87/82%) for AVC and 474 AU/cm2 (Se/Spe = 88/83%) and 358 AU/cm2 (Se/Spe = 80/82%) for AVCd. In Asian patients, they were 2582 AU (Se/Spe = 76/78%) and 924 AU (Se/Spe = 84/80%) for AVC and 640 AU/cm2 (Se/Spe = 82/89%) and 255 AU/cm2 (Se/Spe = 86/80%) for AVCd. Conclusions: The optimal thresholds to identify hemodynamically severe AS in BAV patients are similar in Caucasians but appear to be higher in Asian men, compared with thresholds previously reported in tricuspid aortic valve patients. Nonetheless, the thresholds currently proposed in the guidelines have good accuracy and can be applied in BAV patients to confirm AS severity.

Clinical Value of Stress Transaortic Flow Rate During Dobutamine Echocardiography in Reduced Left Ventricular Ejection Fraction, Low-Gradient Aortic Stenosis: A Multicenter Study.

BACKGROUND: Low rest transaortic flow rate (FR) has been shown previously to predict mortality in low-gradient aortic stenosis. However limited prognostic data exists on stress FR during low-dose dobutamine stress echocardiography. We aimed to assess the value of stress FR for the detection of aortic valve stenosis (AS) severity and the prediction of mortality. METHODS: This is a multicenter cohort study of patients with reduced left ventricular ejection fraction and low-gradient aortic stenosis (aortic valve area <1 cm2 and mean gradient <40 mm Hg) who underwent low-dose dobutamine stress echocardiography to identify the AS severity and presence of flow reserve. The outcome assessed was all-cause mortality. RESULTS: Of the 287 patients (mean age, 75±10 years; males, 71%; left ventricular ejection fraction, 31±10%) over a mean follow-up of 24±30 months there were 127 (44.3%) deaths and 147 (51.2%) patients underwent aortic valve intervention. Higher stress FR was independently associated with reduced risk of mortality (hazard ratio, 0.97 [95% CI, 0.94-0.99]; P=0.01) after adjusting for age, chronic kidney disease, heart failure symptoms, aortic valve intervention, and rest left ventricular ejection fraction. The minimum cutoff for prediction of mortality was stress FR 210 mL/s. Following adjustment to the same important clinical and echocardiographic parameters, among the three criteria of AS severity during stress, ie, the guideline definition of aortic valve area <1cm2 and aortic valve mean gradient ≥40 mm Hg, or aortic valve mean gradient ≥40 mm Hg, or the novel definition of aortic valve area <1 cm2 at stress FR ≥210 mL/s, only the latter was independently associated with mortality (hazard ratio, 1.72 [95% CI, 1.05-2.82]; P=0.03). Furthermore aortic valve area <1cm2 at stress FR ≥210 mL/s was the only severe aortic stenosis criterion that was associated with improved outcome following aortic valve intervention (P<0.001). Guideline-defined stroke volume flow reserve did not predict mortality. CONCLUSIONS: Stress FR during low-dose dobutamine stress echocardiography was useful for the detection of both AS severity and flow reserve and was associated with improved prediction of outcome following aortic valve intervention.

Accuracy of stroke volume measurement with phase-contrast cardiovascular magnetic resonance in patients with aortic stenosis.

BACKGROUND: Phase contrast (PC) cardiovascular magnetic resonance (CMR) in the ascending aorta (AAo) is widely used to calculate left ventricular (LV) stroke volume (SV). The accuracy of PC CMR may be altered by turbulent flow. Measurement of SV at another site is suggested in the presence of aortic stenosis, but very few data validates the accuracy or inaccuracy of PC in that setting. Our objective is to compare flow measurements obtained in the AAo and LV outflow tract (LVOT) in patients with aortic stenosis. METHODS: Retrospective analysis of patients with aortic stenosis who had CMR and echocardiography. Patients with mitral regurgitation were excluded. PC in the AAo and LVOT were acquired to derive SV. LV SV from end-systolic and end-diastolic tracings was used as the reference measure. A difference ≥ 10% between the volumetric method and PC derived SVs was considered discordant. Metrics of turbulence and jet eccentricity were assessed to explore the predictors of discordant measurements. RESULTS: We included 88 patients, 41% with bicuspid aortic valve. LVOT SV was concordant with the volumetric method in 79 (90%) patients vs 52 (59%) patients for AAo SV (p = 0.015). In multivariate analysis, aortic stenosis flow jet angle was a strong predictor of discordant measurement in the AAo (p = 0.003). Mathematical correction for the jet angle improved the concordance from 59 to 91%. Concordance was comparable in patients with bicuspid and trileaflet valves (57% and 62% concordance respectively; p = 0.11). Accuracy of SV measured in the LVOT was not influenced by jet eccentricity. For aortic regurgitation quantification, PC in the AAo had better correlation to volumetric assessments than LVOT PC. CONCLUSION: LVOT PC SV in patients with aortic stenosis and eccentric jet might be more accurate compared to the AAo SV. Mathematical correction for the jet angle in the AAo might be another alternative to improve accuracy.

Established and Emerging Techniques for Pericardial Imaging with Cardiac Magnetic Resonance.

PURPOSE OF REVIEW: Pericardial diseases include a wide range of pathologies and their diagnosis can often be challenging. The goal of this review is to describe the established and emerging CMR imaging techniques used in the assessment of common pericardial diseases and explain the role of pericardial characterization in their diagnosis and management. RECENT FINDINGS: CMR is indicated in cases of diagnostic uncertainty and for a comprehensive evaluation of the pericardium and its impact on the heart. This includes assessment of pericardial anatomy and associated cardiac hemodynamics, quantification and characterization of an effusion, disease staging, tissue characterization, guiding management, and even prognostication in some diseases of the pericardium. An emerging technique, pericardial characterization, utilizes various sequences to diagnose and stage pericardial inflammation, act as a biomarker in recurrent pericarditis, and guide management in inflammatory pericardial conditions. Beyond imaging, it has ushered in an era of tailored therapy for patients with pericardial diseases. Future directions should aim at exploring the role of tissue characterization in various pericardial diseases.

Prosthesis-Patient Mismatch After Aortic Valve Replacement in the PARTNER 2 Trial and Registry.

OBJECTIVES: This study aimed to compare incidence and impact of measured prosthesis-patient mismatch (PPMM) versus predicted PPM (PPMP) after surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR). BACKGROUND: TAVR studies have used measured effective orifice area indexed (EOAi) to body surface area (BSA) to define PPM, but most SAVR series have used predicted EOAi. This difference may contribute to discrepancies in incidence and outcomes of PPM between series. METHODS: The study analyzed SAVR patients from the PARTNER (Placement of Aortic Transcatheter Valves) 2A trial and TAVR patients from the PARTNER 2 SAPIEN 3 Intermediate Risk registry. PPM was classified as moderate if EOAi ≤0.85 cm2/m2 (≤0.70 if obese: body mass index ≥30 kg/m2) and severe if EOAi ≤0.65 cm2/m2 (≤0.55 if obese). PPMM was determined by the core lab-measured EOAi on 30-day echocardiogram. PPMP was determined by 2 methods: 1) using normal EOA reference values previously reported for each valve model and size (PPMP1; n = 929 SAVR, 1,069 TAVR) indexed to BSA; and 2) using normal reference EOA predicted from aortic annulus size measured by computed tomography (PPMP2; n = 864 TAVR only) indexed to BSA. Primary endpoint was the composite of 5-year all-cause death and rehospitalization. RESULTS: The incidence of moderate and severe PPMP was much lower than PPMM in both SAVR (PPMP1: 28.4% and 1.2% vs. PPMM: 31.0% and 23.6%) and TAVR (PPMP1: 21.0% and 0.1% and PPMP2: 17.0% and 0% vs. PPMM: 27.9% and 5.7%). The incidence of severe PPMM and severe PPMP1 was lower in TAVR versus SAVR (P < 0.001). The presence of PPM by any method was associated with higher transprosthetic gradient. Severe PPMP1 was independently associated with events in SAVR after adjustment for sex and Society of Thoracic Surgeons score (hazard ratio: 3.18;95% CI: 1.69-5.96; P < 0.001), whereas no association was observed between PPM by any method and outcomes in TAVR. CONCLUSIONS: EOAi measured by echocardiography results in a higher incidence of PPM following SAVR or TAVR than PPM based on predicted EOAi. Severe PPMP is rare (<1.5%), but is associated with increased all-cause death and rehospitalization after SAVR, whereas it is absent following TAVR.

Left ventricular asymmetric remodeling and subclinical left ventricular dysfunction in patients with calcific aortic valve stenosis - Results from a subanalysis of the PROGRESSA study.

BACKGROUND: LV asymmetric remodeling (LVAR) is a feature commonly found in AS patients and it is presumed to be mainly related to the severity of valve stenosis. The aim of this study was to determine the associated factors and impact on left ventricular (LV) systolic function of LVAR in patients with mild and moderate aortic valve stenosis (AS). METHODS: Clinical, Doppler-echocardiographic and computed-tomographic data of 155 AS patients with preserved LV ejection fraction (≥50%) prospectively recruited in the PROGRESSA study (NCT01679431) were analyzed. LVAR was defined as a septal wall thickness ≥ 13 mm and a ratio of septal/posterior wall thickness > 1.5. LV global longitudinal strain (LV-GLS) was available in 129 patients. Plasma levels of N-terminal natriuretic B-type peptides (Nt-proBNP) were also measured. RESULTS: Mean age was 63 ± 15 years (70% men). LVAR was present in 21% (n = 33) of patients. A series of nested multivariate analysis revealed that age was the only factor associated with LVAR (all p ≤ 0.03). Additionally, these patients had higher baseline Nt-proBNP ratio (median [25-75 percentiles]: 1.04 [0.66-2.41] vs. 0.65 [0.33-1.19], p = 0.02), and significantly reduced LV-GLS (17.9[16.6-19.5] vs. 19.3[17.4-20.7] |%|, p = 0.04). A 1:1 matched analysis showed a significant association of LVAR with reduced LV-GLS (17.9[16.6-19.5] vs. 19.8[18.1-20.7] |%|, p = 0.02) and elevated Nt-proBNP (134[86-348] vs. 83[50-179]pg/ml, p = 0.03). Multivariable analysis also revealed that LVAR remains significantly associated with reduced LV-GLS (p = 0.03) and elevated Nt-proBNP (p = 0.001). LVAR was significantly associated with increased risk of major adverse cardiac events and death (Hazard ratio [95% confidence interval]: 2.32[1.28-4.22], p = 0.006). CONCLUSIONS: LVAR was found in ~20% of patients with mild or moderate AS and was not related to the degree of AS severity or concomitant comorbidities, but rather to older age. LVAR was significantly associated with reduced LV longitudinal systolic function, increased Nt-proBNP levels, and higher risk of major adverse events and death. These findings provide support for closer clinical and echocardiographic surveillance of patients harboring this adverse LV remodeling feature.

Contrast-enhanced computed tomography assessment of aortic stenosis.

OBJECTIVES: Non-contrast CT aortic valve calcium scoring ignores the contribution of valvular fibrosis in aortic stenosis. We assessed aortic valve calcific and non-calcific disease using contrast-enhanced CT. METHODS: This was a post hoc analysis of 164 patients (median age 71 (IQR 66-77) years, 78% male) with aortic stenosis (41 mild, 89 moderate, 34 severe; 7% bicuspid) who underwent echocardiography and contrast-enhanced CT as part of imaging studies. Calcific and non-calcific (fibrosis) valve tissue volumes were quantified and indexed to annulus area, using Hounsfield unit thresholds calibrated against blood pool radiodensity. The fibrocalcific ratio assessed the relative contributions of valve fibrosis and calcification. The fibrocalcific volume (sum of indexed non-calcific and calcific volumes) was compared with aortic valve peak velocity and, in a subgroup, histology and valve weight. RESULTS: Contrast-enhanced CT calcium volumes correlated with CT calcium score (r=0.80, p<0.001) and peak aortic jet velocity (r=0.55, p<0.001). The fibrocalcific ratio decreased with increasing aortic stenosis severity (mild: 1.29 (0.98-2.38), moderate: 0.87 (1.48-1.72), severe: 0.47 (0.33-0.78), p<0.001) while the fibrocalcific volume increased (mild: 109 (75-150), moderate: 191 (117-253), severe: 274 (213-344) mm3/cm2). Fibrocalcific volume correlated with ex vivo valve weight (r=0.72, p<0.001). Compared with the Agatston score, fibrocalcific volume demonstrated a better correlation with peak aortic jet velocity (r=0.59 and r=0.67, respectively), particularly in females (r=0.38 and r=0.72, respectively). CONCLUSIONS: Contrast-enhanced CT assessment of aortic valve calcific and non-calcific volumes correlates with aortic stenosis severity and may be preferable to non-contrast CT when fibrosis is a significant contributor to valve obstruction.

Effect of Regional Upper Septal Hypertrophy on Echocardiographic Assessment of Left Ventricular Mass and Remodeling in Aortic Stenosis.

BACKGROUND: Transthoracic echocardiography (TTE) is the reference method for evaluation of aortic stenosis (AS), and it is extensively used to quantitate left ventricular (LV) mass and volumes. Regional upper septal hypertrophy (USH) or septal bulge is a frequent finding in patients with AS and may lead to overestimation of LV mass when using linear measurements. The objective of this study was to compare estimates of LV mass obtained by two-dimensional transthoracic echocardiographic LV dimensions measured at different levels of the LV cavity with those obtained by cardiovascular magnetic resonance (CMR). METHODS: One hundred six patients (mean age, 63 ± 15 years; 68% men) with AS were included in this subanalysis of the PROGRESSA study. Two-dimensional transthoracic echocardiographic measurements of LV dimensions were obtained at the basal level (BL; as recommended in guidelines), immediately below the septal bulge (BSB), and at a midventricular level (ML). Regional USH was defined as a basal interventricular septal thickness ≥ 13 mm and >1.3 times the thickness of the septal wall at the ML. Agreement between transthoracic echocardiographic and CMR measures was evaluated using Bland-Altman analysis. RESULTS: The distribution of AS severity was mild in 23%, moderate in 57%, and severe in 20% of patients. Regional USH was present in 28 patients (26%). In the whole cohort, two-dimensional TTE overestimated LV mass (bias: BL, +60 ± 31 g; BSB, +59 ± 32 g; ML, +54 ± 32 g; P = .02). The biplane Simpson method slightly but significantly underestimated LV end-diastolic volume (bias -10 ± 20 mL, P < .001) compared with CMR. Overestimation of LV mass was more marked in patients with USH when measuring at the BL and was significantly lower when measuring LV dimensions at the ML (P < .025 vs BL and BSB). CONCLUSIONS: Two-dimensional TTE systematically overestimated LV mass and underestimated LV volumes compared with CMR. However, the bias between TTE and CMR was less important when measuring at the ML. Measurements at the BL as suggested in guidelines should be avoided, and measurements at the ML should be preferred in patients with AS, especially in those with USH.

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.

Structural Deterioration of Transcatheter Versus Surgical Aortic Valve Bioprostheses in the PARTNER-2 Trial.

BACKGROUND: It is unknown whether transcatheter valves will have similar durability as surgical bioprosthetic valves. Definitions of structural valve deterioration (SVD), based on valve related reintervention or death, underestimate the incidence of SVD. OBJECTIVES: This study sought to determine and compare the 5-year incidence of SVD, using new standardized definitions based on echocardiographic follow-up of valve function, in intermediate-risk patients with severe aortic stenosis given transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR) in the PARTNER (Placement of Aortic Transcatheter Valves) 2A trial and registry. METHODS: In the PARTNER 2A trial, patients were randomly assigned to receive either TAVR with the SAPIEN XT or SAVR, whereas in the SAPIEN 3 registry, patients were assigned to TAVR with the SAPIEN 3. The primary endpoint was the incidence of SVD, that is, the composite of SVD-related hemodynamic valve deterioration during echocardiographic follow-up and/or SVD-related bioprosthetic valve failure (BVF) at 5 years. RESULTS: Compared with SAVR, the SAPIEN-XT TAVR cohort had a significantly higher 5-year exposure adjusted incidence rates (per 100 patient-years) of SVD (1.61 ± 0.24% vs. 0.63 ± 0.16%), SVD-related BVF (0.58 ± 0.14% vs. 0.12 ± 0.07%), and all-cause (structural or nonstructural) BVF (0.81 ± 0.16% vs. 0.27 ± 0.10%) (p ≤ 0.01 for all). The 5-year rates of SVD (0.68 ± 0.18% vs. 0.60 ± 0.17%; p = 0.71), SVD-related BVF (0.29 ± 0.12% vs. 0.14 ± 0.08%; p = 0.25), and all-cause BVF (0.60 ± 0.15% vs. 0.32 ± 0.11%; p = 0.32) in SAPIEN 3 TAVR were not significantly different to a propensity score matched SAVR cohort. The 5-year rates of SVD and SVD-related BVF were significantly lower in SAPIEN 3 versus SAPIEN XT TAVR matched cohorts. CONCLUSIONS: Compared with SAVR, the second-generation SAPIEN XT balloon-expandable valve has a higher 5-year rate of SVD, whereas the third-generation SAPIEN 3 has a rate of SVD that was not different from SAVR. (The PARTNER II Trial: Placement of AoRTic TraNscathetER Valves - PII A [PARTNERII A]; NCT01314313; The PARTNER II Trial: Placement of AoRTic TraNscathetER Valves II - PARTNER II - PARTNERII - S3 Intermediate [PARTNERII S3i]; NCT03222128).

Estimation of Stroke Volume and Aortic Valve Area in Patients with Aortic Stenosis: A Comparison of Echocardiography versus Cardiovascular Magnetic Resonance.

BACKGROUND: In aortic stenosis, accurate measurement of left ventricular stroke volume (SV) is essential for the calculation of aortic valve area (AVA) and the assessment of flow status. Current American Society of Echocardiography and European Association of Cardiovascular Imaging guidelines suggest that measurements of left ventricular outflow tract diameter (LVOTd) at different levels (at the annulus vs 5 or 10 mm below) yield similar measures of SV and AVA. The aim of this study was to assess the effect of the location of LVOTd measurement on the accuracy of SV and AVA measured on transthoracic echocardiography (TTE) compared with cardiovascular magnetic resonance (CMR). METHODS: One hundred six patients with aortic stenosis underwent both TTE and CMR. SV was estimated on TTE using the continuity equation with LVOTd measurements at four locations: at the annulus and 2, 5, and 10 mm below annulus. SV was also determined on CMR using phase contrast acquired in the aorta (SVCMR-PC), and a hybrid AVACMR-PC was calculated by dividing SVCMR-PC by the transthoracic echocardiographic Doppler aortic velocity-time integral. Comparison between methods was made using Bland-Altman analysis. RESULTS: Compared with the referent method of phase-contrast CMR for the estimation of SVCMR-PC and AVACMR-PC (SVCMR-PC 83 ± 16 mL, AVACMR-PC 1.27 ± 0.35 cm2), the best agreement was obtained by measuring LVOTd at the annulus or 2 mm below (P = NS), whereas measuring 5 and 10 mm below the annulus resulted in significant underestimation of SV and AVA by up to 15.9 ± 17.3 mL and 0.24 ± 0.28 cm2, respectively (P < .01 for all). Accuracy for classification of low flow was best at the annulus (86%) and 2 mm below (82%), whereas measuring 5 and 10 mm below the annulus significantly underperformed (69% and 61%, respectively, P < .001). CONCLUSIONS: Measuring LVOTd at the annulus or very close to it provides the most accurate measures of SV and AVA, whereas measuring LVOTd 5 or 10 mm below significantly underestimates these parameters and leads to significant overestimation of the severity of aortic stenosis and prevalence of low-flow status.

Echocardiographic Results of Transcatheter Versus Surgical Aortic Valve Replacement in Low-Risk Patients: The PARTNER 3 Trial.

BACKGROUND: This study aimed to compare echocardiographic findings in low-risk patients with severe aortic stenosis after surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR). METHODS: The PARTNER 3 trial (Placement of Aortic Transcatheter Valves) randomized 1000 patients with severe aortic stenosis and low surgical risk to undergo either transfemoral TAVR with the balloon-expandable SAPIEN 3 valve or SAVR. Transthoracic echocardiograms obtained at baseline and at 30 days and 1 year after the procedure were analyzed by a consortium of 2 echocardiography core laboratories. RESULTS: The percentage of moderate or severe aortic regurgitation (AR) was low and not statistically different between the TAVR and SAVR groups at 30 days (0.8% versus 0.2%; P=0.38). Mild AR was more frequent after TAVR than SAVR at 30 days (28.8% versus 4.2%; P<0.001). At 1 year, mean transvalvular gradient (13.7±5.6 versus 11.6±5.0 mm Hg; P=0.12) and aortic valve area (1.72±0.37 versus 1.76±0.42 cm2; P=0.12) were similar in TAVR and SAVR. The percentage of severe prosthesis-patient mismatch at 30 days was low and similar between TAVR and SAVR (4.6 versus 6.3%; P=0.30). Valvulo-arterial impedance (Zva), which reflects total left ventricular hemodynamic burden, was lower with TAVR than SAVR at 1 year (3.7±0.8 versus 3.9±0.9 mm Hg/mL/m2; P<0.001). Tricuspid annulus plane systolic excursion decreased and the percentage of moderate or severe tricuspid regurgitation increased from baseline to 1 year in SAVR but remained unchanged in TAVR. Irrespective of treatment arm, high Zva and low tricuspid annulus plane systolic excursion, but not moderate to severe AR or severe prosthesis-patient mismatch, were associated with increased risk of the composite end point of mortality, stroke, and rehospitalization at 1 year. CONCLUSIONS: In patients with severe aortic stenosis and low surgical risk, TAVR with the SAPIEN 3 valve was associated with similar percentage of moderate or severe AR compared with SAVR but higher percentage of mild AR. Transprosthetic gradients, valve areas, percentage of severe prosthesis-patient mismatch, and left ventricular mass regression were similar in TAVR and SAVR. SAVR was associated with significant deterioration of right ventricular systolic function and greater tricuspid regurgitation, which persisted at 1 year. High Zva and low tricuspid annulus plane systolic excursion were associated with worse outcome at 1 year whereas AR and severe prosthesis-patient mismatch were not. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02675114.

Transvalvular Flow, Sex, and Survival After Valve Replacement Surgery in Patients With Severe Aortic Stenosis.

BACKGROUND: The respective impacts of transvalvular flow, gradient, sex, and their interactions on mortality in patients with severe aortic stenosis undergoing surgical aortic valve replacement (AVR) are unknown. OBJECTIVES: This study sought to compare the impact of pre-operative flow-gradient patterns on mortality after AVR and to examine whether there are sex differences. METHODS: This study analyzed clinical, echocardiographic, and outcome data prospectively collected in 1,490 patients (544 women [37%]), with severe aortic stenosis and preserved left ventricular ejection fraction who underwent AVR. RESULTS: In this cohort, 601 patients (40%) had normal flow (NF) with high gradient (HG), 405 (27%) NF with low gradient (LG), 246 (17%) paradoxical low flow (LF)/HG, and 238 (16%) LF/LG. During a median follow-up of 2.42 years (interquartile range: 1.04 to 4.29 years), 167 patients died. Patients with LF/HG exhibited the highest mortality after AVR (hazard ratio [HR]: 2.01; 95% confidence interval [CI]: 1.33 to 3.03; p < 0.01), which remained significant after multivariate adjustment (HR: 1.96; 95% CI: 1.29 to 2.98; p < 0.01). Both LF/LG and NF/LG patients had comparable outcome to NF/HG (p ≥ 0.47). Optimal thresholds of stroke volume index were obtained for men (40 ml/m2) and women (32 ml/m2). Using these sex-specific cutpoints, paradoxical LF was independently associated with increased mortality in both women (adjusted HR: 2.05; 95% CI: 1.21 to 3.47; p < 0.01) and men (adjusted HR: 1.54; 95% CI: 1.02 to 2.32; p = 0.042), whereas guidelines' threshold (35 ml/m2) does not. CONCLUSIONS: Paradoxical LF/HG was associated with higher mortality following AVR, suggesting that a reduced flow is a marker of disease severity even in patients with HG aortic stenosis. Early surgical AVR (i.e., before gradient attains 40 mm Hg) might be preferable in these patients. Furthermore, the use of sex-specific thresholds (<40 ml/m2 for men and <32 ml/m2 for women) to define low-flow outperforms the guidelines' threshold of 35 ml/m2 in risk stratification after AVR.