A Novel Echocardiographic Parameter to Confirm Low-Gradient Aortic Stenosis Severity.

Background: In patients with low-gradient (LG) aortic stenosis (AS), confirming disease severity and indication of intervention often requires dobutamine stress echocardiography (DSE) or aortic valve calcium scoring by computed tomography. We hypothesized that the mean transvalvular pressure gradient to effective orifice area ratio (MG/EOA, in mm Hg/cm2) measured during rest echocardiography identifies true-severe AS (TSAS) and is associated with clinical outcomes in patients with low-flow, LG-AS. Objectives: The purpose of this study was to evaluate the diagnostic and prognostic value of MG/EOA ratio. Methods: The diagnostic accuracy of MG/EOA ratio to identify TSAS was retrospectively assessed in: 1) an in vitro data set obtained in a circulatory model including 93 experimental conditions; and 2) an in vivo data set of 188 patients from the TOPAS (True or Pseudo-Severe Aortic Stenosis) study (NCT01835028). Receiver operating characteristic curves were used to assess the diagnostic accuracy of MG/EOA ratio for identifying TSAS, and Cox proportional hazards regression analyses were performed to assess its association with clinical outcomes. Results: The optimal cutoff of MG/EOA ratio to identify TSAS in patients with low-flow, LG-AS was ≥25 mm Hg/cm2 (correct classification 85%), as well as in vitro (100%). During a median follow-up of 1.41 ± 0.75 years, 146 (78%) patients met the composite endpoint of aortic valve replacement or all-cause mortality. A MG/EOA ratio ≥25 mm Hg/cm2 was independently associated with an increased risk of the composite endpoint (adjusted HR: 2.36 [95% CI: 1.63-3.42], P < 0.001). The Harell's C-index of MG/EOA was 0.68, equaling projected EOA (0.67) measured by DSE. Conclusions: MG/EOA ratio can be useful in low-flow, LG-AS to confirm AS severity and may complement DSE or aortic valve calcium scoring.

Dobutamine Stress Echocardiography in Low-Gradient Aortic Stenosis.

IMPORTANCE: Guidelines recommend the use of dobutamine stress echocardiography (DSE) in patients with low-gradient aortic stenosis (AS) and left ventricular ejection fraction (LVEF) <50%. However, a paucity of DSE data exists when LVEF >35%. OBJECTIVE: To examine the diagnostic accuracy of DSE in patients with low-gradient AS with a wide range of LVEF and to examine the interaction between the diagnostic accuracy of DSE and LVEF. DESIGN, SETTING, AND PARTICIPANTS: Patients with mean gradient <40 mm Hg, aortic valve area <1.0 cm2, and stroke volume index ≤35 mL/m2 undergoing DSE and cardiac computer tomography (C-CT) were identified from 3 prospectively collected patient cohorts and stratified according to LVEF: LVEF<35%, LVEF 35% to 50%, and LVEF>50%. EXPOSURE: Dobutamine stress echocardiography and C-CT were performed on patients with low-gradient AS. MAIN OUTCOMES AND MEASURES: Severe AS was defined as aortic valve calcification score ≥2,000 arbitrary units (AU) among men and ≥1,200 AU for women on C-CT. RESULTS: Of 221 patients included in the study, 78 (35%) presented with LVEF <35%, 67 (30%) with LVEF 35% to 50%, and 76 (34%) with LVEF >50%. Mean-gradient and aortic valve peak velocity during DSE showed significant diagnostic heterogeneity between LVEF groups, being most precise when LVEF <35% (both areas under the curve [AUC] = 0.90), albeit with optimal thresholds of 30 mm Hg and 377 cm/sec and a limited diagnostic yield in patients with LVEF ≥35% (AUC = 0.67 and 0.66 in LVEF 35% to 50% and AUC = 0.65 and 0.60 in LVEF ≥50%). Using guideline thresholds led to a sensitivity/specificity of 49%/84% for all patients with LVEF <50%. CONCLUSION AND RELEVANCE: While DSE is safe and leads to an increase in stroke volume in patients with low-gradient AS regardless of LVEF, the association between DSE gradients and AS severity assessed by C-CT demonstrates important heterogeneity depending on LVEF, with the highest accuracy in patients with LVEF <35%.

Prevalence, Characteristics, and Impact on Prognosis of Aortic Stenosis in Patients With Cardiac Amyloidosis.

BACKGROUND: Cardiac amyloidosis (CA) is frequently found in older patients with aortic stenosis (AS). However, the prevalence of AS among patients with CA is unknown. The objective was to study the prevalence and prognostic impact of AS among patients with CA. METHODS AND RESULTS: We conducted a retrospective analysis of a prospective registry comprising 976 patients with native aortic valves who were confirmed with wild type transthyretin amyloid (ATTRwt), hereditary variant transthyretin amyloid (ATTRv), or immunoglobulin light-chain (AL) CA. CA patients' echocardiograms were re-analyzed focusing on the aortic valve. Multivariable Cox regression analysis was performed to assess the mortality risk associated with moderate or greater AS in ATTRwt CA. The crude prevalence of AS among patients with CA was 26% in ATTRwt, 8% in ATTRv, and 5% in AL. Compared with population-based controls, all types of CA had higher age- and sex-standardized rate ratios (SRRs) of having any degree of AS (AL: SRR, 2.62; 95% Confidence Interval (CI) [1.09-3.64]; ATTRv: SRR, 3.41; 95%CI [1.64-4.60]; ATTRwt: SRR, 10.8; 95%CI [5.25-14.53]). Compared with hospital controls, only ATTRwt had a higher SRR of having any degree of AS (AL: SRR, 0.97, 95%CI [0.56-1.14]; ATTRv: SRR, 1.27; 95%CI [0.85-1.44]; ATTRwt: SRR, 4.01; 95%CI [2.71-4.54]). Among patients with ATTRwt, moderate or greater AS was not associated with increased all-cause death after multivariable adjustment (hazard ratio, 0.71; 95%CI [0.42-1.19]; P=0.19). CONCLUSIONS: Among patients with CA, ATTRwt but not ATTRv or AL is associated with a higher prevalence of patients with AS compared with hospital controls without CA, even after adjusting for age and sex. In our population, having moderate or greater AS was not associated with a worse outcome in patients with ATTRwt.

Impact of sex and sex hormones on pathophysiology and progression of aortic stenosis in a murine model.

The lesions observed in AS have been shown to be sex specific, with women presenting extensive fibrotic remodeling while men developing more calcification deposit. We thus aimed to evaluate the influence of sex and sex hormones on the pathophysiology of aortic valve stenosis (AS) in our mouse model of AS. LDLr-/- ApoB100/100 IGF-II+/- mice (n = 210) were separated in six different groups: (1) intact male (IM), (2) intact female (IF), (3) castrated male (CM), (4) ovariectomized females (OF), (5) CM with testosterone supplementation (CMT), and (6) OF with 17ß-estradiol supplementation (OFE). Mice were fed a high-fat/high-sucrose/high-cholesterol diet for 6 months. Hemodynamic progression of AS was followed by transthoracic echocardiography (at 12 and 36 weeks) and analyzed in all mice alive at 36 weeks. Aortic valves were collected for histological and digital droplet PCR* analysis. Increases in peak velocity were comparable in IF and IM (24.2 ± 5.7 vs. 25.8 ± 5.3 cm/s; p = 0.68), but IF presented with less severe AS. Between the three groups of male mice, AS progression was more important in IM (increase in peak velocity: 24.2 ± 5.7 cm/s; p < 0.001) compared to CM (6.2 ± 1.4; p = 0.42), and CMT (15.1 ± 3.5; p = 0.002). In the three groups of female mice, there were no statistical differences in AS progression. Digital PCR analysis revealed an important upregulation of the osteogenic gene RunX2 in IM (p < 0.0001) and downregulation of the pro-calcifying gene ALPL in IF (p < 0.05). Male sex and testosterone play an important role in upregulation of pro-calcifying genes and hemodynamic progression of AS. However, female mice appeared to be protected against calcification, characterized by downregulation of pro-osteogenic genes, but presented a similar AS hemodynamic progression.

Comprehensive myocardial characterization using cardiac magnetic resonance associates with outcomes in low gradient severe aortic stenosis.

AIMS: This study sought to compare cardiac magnetic resonance (CMR) characteristics according to different flow/gradient patterns of aortic stenosis (AS) and to evaluate their prognostic value in patients with low-gradient AS. METHODS AND RESULTS: This international prospective multicentric study included 147 patients with low-gradient moderate to severe AS who underwent comprehensive CMR evaluation of left ventricular global longitudinal strain (LVGLS), extracellular volume fraction (ECV), and late gadolinium enhancement (LGE). All patients were classified as followings: classical low-flow low-gradient (LFLG) [mean gradient (MG) < 40 mmHg and left ventricular ejection fraction (LVEF) < 50%]; paradoxical LFLG [MG < 40 mmHg, LVEF ≥ 50%, and stroke volume index (SVi) < 35 ml/m2]; and normal-flow low-gradient (MG < 40 mmHg, LVEF ≥ 50%, and SVi ≥ 35 ml/m2). Patients with classical LFLG (n = 90) had more LV adverse remodelling including higher ECV, and higher LGE and volume, and worst LVGLS. Over a median follow-up of 2 years, 43 deaths and 48 composite outcomes of death or heart failure hospitalizations occurred. Risks of adverse events increased per tertile of LVGLS: hazard ratio (HR) = 1.50 [95% CI, 1.02-2.20]; P = 0.04 for mortality; HR = 1.45 [1.01-2.09]; P < 0.05 for composite outcome; per tertile of ECV, HR = 1.63 [1.07-2.49]; P = 0.02 for mortality; HR = 1.54 [1.02-2.33]; P = 0.04 for composite outcome. LGE presence also associated with higher mortality, HR = 2.27 [1.01-5.11]; P < 0.05 and composite outcome, HR = 3.00 [1.16-7.73]; P = 0.02. The risk of mortality and the composite outcome increased in proportion to the number of impaired components (i.e. LVGLS, ECV, and LGE) with multivariate adjustment. CONCLUSIONS: In this international prospective multicentric study of low-gradient AS, comprehensive CMR assessment provides independent prognostic value that is cumulative and incremental to clinical and echocardiographic characteristics.

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.

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.

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.

Comparison of Early Surgical or Transcatheter Aortic Valve Replacement Versus Conservative Management in Low-Flow, Low-Gradient Aortic Stenosis Using Inverse Probability of Treatment Weighting: Results From the TOPAS Prospective Observational Cohort Study.

Background No randomized comparison of early (ie, ≤3 months) aortic valve replacement (AVR) versus conservative management or of transcatheter AVR (TAVR) versus surgical AVR has been conducted in patients with low-flow, low-gradient (LFLG) aortic stenosis (AS). Methods and Results A total of 481 consecutive patients (75±10 years; 71% men) with LFLG AS (aortic valve area ≤0.6 cm2/m2 and mean gradient <40 mm Hg), 72% with classic LFLG and 28% with paradoxical LFLG, were prospectively recruited in the multicenter TOPAS (True or Pseudo Severe Aortic Stenosis) study. True-severe AS or pseudo-severe AS was adjudicated by flow-independent criteria. During follow-up (median [IQR] 36 [11-60] months), 220 patients died. Using inverse probability of treatment weighting to address the bias of nonrandom treatment assignment, early AVR (n=272) was associated with a major overall survival benefit (hazard ratio [HR], 0.34 [95% CI, 0.24-0.50]; P<0.001). This benefit was observed in patients with true-severe AS but also with pseudo-severe AS (HR, 0.38 [95% CI, 0.18-0.81]; P=0.01), and in classic (HR, 0.33 [95% CI, 0.22-0.49]; P<0.001) and paradoxical LFLG AS (HR, 0.42 [95% CI, 0.20-0.92]; P=0.03). Compared with conservative management in the conventional multivariate model, trans femoral TAVR was associated with the best survival (HR, 0.23 [95% CI, 0.12-0.43]; P<0.001), followed by surgical AVR (HR, 0.36 [95% CI, 0.23-0.56]; P<0.001) and alternative-access TAVR (HR, 0.51 [95% CI, 0.31-0.82]; P=0.007). In the inverse probability of treatment weighting model, trans femoral TAVR appeared to be superior to surgical AVR (HR [95% CI] 0.28 [0.11-0.72]; P=0.008) with regard to survival. Conclusions In this large prospective observational study of LFLG AS, early AVR appeared to confer a major survival benefit in both classic and paradoxical LFLG AS. This benefit seems to extend to the subgroup with pseudo-severe AS. Our findings suggest that TAVR using femoral access might be the best strategy in these patients. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01835028.

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).

Sex-differences in echocardiographic assessment of aortic valve in young adult LDLr-/-/ApoB100/100/IGF-II+/- mice.

BACKGROUND: LDLr-/-/ApoB100/100/IGF-II+/- mice are used as a calcific aortic valve disease (CAVD) model. However, normal aortic valve hemodynamics i.e. remotely from CAVD onset and the sex-related differences are poorly known. METHODS AND RESULTS: Four groups of mice, intact males (IM, n = 49) and females (IF, n = 50), castrated males (CxM, n = 79) and ovariectomized females (OxF: 73), underwent a Doppler-echocardiography at 12 weeks of age. Gonadectomy was performed at 8 weeks. Aortic valve assessment using effective orifice area (EOA, using the continuity equation) and peak aortic transvalvular velocity (VPeak) was feasible in 89% of the mice with good to excellent reliability (intraclass correlation coefficients ranging from 0.90 to 0.98, p < 0.001). Mean VPeak was 104 ± 17 cm/s and mean EOA was 1.18*10-2 ± 0.22*10-2 cm2. EOA indexed to body surface area was 1.5 ± 0.3 cm2/m2. The 95th percentile of Vpeak was 132 cm/s and the 5th percentile of indexed EOA was 1.0 cm2/m2. Interestingly, IM had the highest VPeak (114 ± 14 cm/s) vs each of the other groups (CxM: 106 ± 19 cm/s, OxF: 97 ± 13 cm/s and IF: 96 ± 12 cm/s, ANOVA and corrected p < 0.001). This was mostly explained by a higher stroke volume (ANOVA and corrected p < 0.001) in IM compared to other groups. There were no major sex-differences in ventricular systolic function parameters. CONCLUSION: In LDLr-/-/ApoB100/100/IGF-II CAVD mice model, an aortic EOA <0.8*10-2 cm2 (or indexed EOA <1.0cm2/m2), and a peak aortic valve velocity > 132 cm/s may be proposed as thresholds to define CAVD. Intact male mice appear to have higher velocities.

Outcome of Flow-Gradient Patterns of Aortic Stenosis After Aortic Valve Replacement: An Analysis of the PARTNER 2 Trial and Registry.

BACKGROUND: Although aortic valve replacement is associated with a major benefit in high-gradient (HG) severe aortic stenosis (AS), the results in low-gradient (LG, mean gradient <40 mm Hg) AS are conflicting. LG severe AS may be subdivided in classical low-flow (left ventricular ejection fraction <50%) and LG (CLF-LG); paradoxical low-flow (left ventricular ejection fraction ≥50% but stroke volume index <35 mL/m2) and LG; and normal-flow (left ventricular ejection fraction ≥50% and stroke volume index ≥35 mL/m2) and LG. The primary objective is to determine in the PARTNER 2 trial (The Placement of Aortic Transcatheter Valves) and registry the outcomes after aortic valve replacement of the 4 flow-gradient groups. METHODS: A total of 3511 patients from the PARTNER 2 Cohort A randomized trial (n=1910) and SAPIEN 3 registry (n=1601) were included. The flow-gradient pattern was determined at baseline transthoracic echocardiography and classified as follows: (1) HG; (2) CLF-LG; (3) paradoxical low-flow-LG; and (4) normal-flow-LG. The primary end point for this analysis was the composite of (1) death; (2) rehospitalization for heart failure symptoms and valve prosthesis complication; or (3) stroke. RESULTS: The distribution was HG, 2229 patients (63.5%); CLF-LG, 689 patients (19.6%); paradoxical low-flow-LG, 247 patients (7.0%); and normal-flow-LG, 346 patients (9.9%). The 2-year rate of primary end point was higher in CLF-LG (38.8%) versus HG: 31.8% (P=0.002) and normal-flow-LG: 32.1% (P=0.05) but was not statistically different from paradoxical low-flow-LG: 33.6% (P=0.18). There was no significant difference in the 2-year rates of clinical events between transcatheter aortic valve replacement versus surgical aortic valve replacement in the whole cohort and within each flow-gradient group. CONCLUSIONS: The LG AS pattern was highly prevalent (36.5%) in the PARTNER 2 trial and registry. CLF-LG was the most common pattern of LG AS and was associated with higher rates of death, rehospitalization, or stroke at 2 years compared with the HG group. Clinical outcomes were as good in the LG AS groups with preserved left ventricular ejection fraction compared with the HG group.

Cardiovascular Implications of the COVID-19 Pandemic: A Global Perspective.

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), represents the pandemic of the century, with approximately 3.5 million cases and 250,000 deaths worldwide as of May 2020. Although respiratory symptoms usually dominate the clinical presentation, COVID-19 is now known to also have potentially serious cardiovascular consequences, including myocardial injury, myocarditis, acute coronary syndromes, pulmonary embolism, stroke, arrhythmias, heart failure, and cardiogenic shock. The cardiac manifestations of COVID-19 might be related to the adrenergic drive, systemic inflammatory milieu and cytokine-release syndrome caused by SARS-CoV-2, direct viral infection of myocardial and endothelial cells, hypoxia due to respiratory failure, electrolytic imbalances, fluid overload, and side effects of certain COVID-19 medications. COVID-19 has profoundly reshaped usual care of both ambulatory and acute cardiac patients, by leading to the cancellation of elective procedures and by reducing the efficiency of existing pathways of urgent care, respectively. Decreased use of health care services for acute conditions by non-COVID-19 patients has also been reported and attributed to concerns about acquiring in-hospital infection. Innovative approaches that leverage modern technologies to tackle the COVID-19 pandemic have been introduced, which include telemedicine, dissemination of educational material over social media, smartphone apps for case tracking, and artificial intelligence for pandemic modelling, among others. This article provides a comprehensive overview of the pathophysiology and cardiovascular implications of COVID-19, its impact on existing pathways of care, the role of modern technologies to tackle the pandemic, and a proposal of novel management algorithms for the most common acute cardiac conditions.

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.

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.

Mitral Regurgitation in Low-Flow, Low-Gradient Aortic Stenosis Patients Undergoing TAVR: Insights From the TOPAS-TAVI Registry.

OBJECTIVES: This study sought to determine the incidence, clinical impact, and changes over time of mitral regurgitation (MR) in patients with low-flow, low-gradient aortic stenosis (LFLG-AS) undergoing transcatheter aortic valve replacement (TAVR). BACKGROUND: Few data exist on the clinical impact and changes in severity over time of MR in patients with LFLG-AS undergoing TAVR. METHODS: A total of 308 TAVR candidates with LFLG-AS were included. Patients were categorized according to MR severity at baseline, and presence of MR improvement at 12-month follow-up. Clinical outcomes were assessed at 1 and 12 months (+ echocardiography), and yearly thereafter. RESULTS: Baseline mild and moderate-to-severe MR were present in 118 (38.3%) and 115 (37.3%) patients, respectively. MR was of functional and mixed etiology in 77.2% and 22.7% of patients, respectively. A total of 131 patients (42.5%) died after a median follow-up of 2 (1 to 3) years. Baseline moderate-or-greater MR had no impact on mortality (hazard ratio [HR]: 1.34; 95% confidence interval [CI]: 0.72 to 2.48) or heart failure hospitalization (HR: 1.02; 95% CI: 0.49 to 2.10). At 1-year follow-up, MR improved in 44.3% of patients and remained unchanged/worsened in 55.7%. The lack of MR improvement was associated with a higher risk of all-cause and cardiac mortality (HR: 2.02; 95% CI: 1.29 to 3.17; HR: 3.03; 95% CI: 1.27 to 7.23, respectively), rehospitalization for cardiac causes (HR: 1.50; 95% CI: 1.04 to 2.15), and an increased overall-mortality/heart failure rehospitalization (HR: 1.94; 95% CI: 1.25 to 3.02). A higher baseline left ventricular end-diastolic diameter and a higher increase in left ventricular ejection fraction were found to be independent predictors of MR improvement at 1-year follow-up (odds ratio: 0.69; 95% CI: 0.51 to 0.94; and odds ratio: 0.81; 95% CI: 0.67 to 0.96, respectively). CONCLUSIONS: Most TAVR candidates with LFLG-AS had some degree of MR, of functional origin in most cases. MR improved in about one-half of patients, with larger left ventricular size and a higher increase in left ventricular ejection fraction post-TAVR determining MR improvement over time. The lack of MR improvement at 1 year was associated with poorer outcomes.

Dobutamine Stress Echocardiography in Low-Flow, Low-Gradient Aortic Stenosis: Flow Reserve Does Not Matter Anymore.

See Article by Sato et al.