Nishimura, Rick A.

ABSTRACT Background The assessment of aortic stenosis (AS) severity remains a challenge in some patients, and hemodynamic exercise testing has been proposed as a diagnostic tool in this population. However, the current understanding of exercise hemodynamics in AS is limited. Methods Retrospective review of 34 adults (aged ≥ 18 years) with ≥ moderate AS and preserved left ventricular ejection fraction (LVEF) undergoing exercise invasive hemodynamics (supine cycle protocol) with simultaneous measurement of aortic and left ventricular pressures. Results Age was 77.1 (IQR 68.6; 84.1) years, and 50% were female. LVEF was 62.1 ± 6.6%. All patients were symptomatic. Resting aortic valve area (AVA) was 1.0 ± 0.2 cm 2 and aortic valve (AV) systolic mean gradient 22.0 ± 7.3 mmHg. At peak exercise (40 [IQR 30; 60] W), AV systolic mean gradient (Δ3 [0.6; 7] mmHg, p < 0.001) and AVA (Δ0.2 [0; 0.6] cm 2 , p = 0.002) significantly increased, while stroke volume (SV) did not (Δ6.8 ± 19.4 ml; p = 0.07). Exercise‐induced changes in AV systolic mean gradient were directly related to changes in cardiac output ( r = 0.53, p = 0.003), being inversely related to exercise systemic vascular resistance ( r = −0.60, p = 0.002). Elevated pulmonary artery wedge pressure was present in 41.2% at rest (≥ 15 mmHg) and 69.7% during exercise (≥ 25 mmHg). Conclusions Symptomatic patients with ≥ moderate AS and preserved LVEF experience small increases in AV mean gradient with exercise, and unlike the normal physiological response to exercise, there was no significant increase in SV. In most patients, AVA rose during exercise. Exercise‐induced elevation in filling pressures was highly prevalent.

This Viewpoint discusses the use of aortic valve intervention vs watchful waiting for patients with asymptomatic aortic stenosis.

Introduction: The relationship between aortic stenosis (AS) severity, AS-related symptoms, and clinical outcomes is poorly understood. Research Question: Does a history of AS-related symptoms at the time of diagnosis affect clinical outcomes including death and AS-related hospitalization? Methods: Using a combination of natural language processing algorithms and administrative codes, we ascertained physician-assessed AS, AS severity, and AS-related symptoms (chest pain, acute coronary syndrome, syncope, presyncope, orthopnea, dyspnea, PND, and worsening heart failure) in the year prior or up to 60 days after an initial AS diagnosis among 602,821 adults with echocardiograms in a large, integrated health system from 2010-2019. We examined multivariable associations between AS severity and recent AS-related symptoms for the outcomes of death and AS-related hospitalizations using Cox models. Results: Among 40,333 patients identified with incident AS, the majority had recent AS-related symptoms (mild: 80%, mild-moderate: 77%, moderate: 77%, moderate-severe: 85%, and severe AS: 87%). Patients with recent symptoms were older (mean [SD] age 78 [10] vs 75 [11] years; p<0.01), more likely female (51% vs 47%; p<0.01), and had a higher comorbidity burden. In unadjusted analyses, symptom status was a strong discriminator of risk over a median (IQR) of 2.2 (0.8-4.3) years of follow-up ( Figure ). After multivariable adjustment, AS-related symptoms remained strongly associated with death and AS-related hospitalization across the spectrum of AS severity, with moderate symptomatic patients having risk similar to severe asymptomatic patients. Conclusions: The majority of patients diagnosed with AS have recent and/or active AS-related symptoms, which is associated with a significantly increased risk of adverse outcomes. Incorporating symptom status across the individual grades of AS may improve risk stratification beyond AS severity alone.

Introduction: Mitral paravalvular leak (PVL) occurs in 7-17% of patients after mitral valve surgery. The percutaneous closure of these defects has become a novel treatment to prevent repeat operations. Hypothesis: We hypothesize flow dynamics correlate with clinical outcomes of patients undergoing percutaneous mitral PVL closure. Methods: We retrospectively studied 148 patients who underwent percutaneous PVL closure between 2004 and 2014 at Mayo Clinic. We measured the continuous wave (CW) Doppler time velocity integral (TVI), E velocity (as a surrogate for V wave) across the mitral valve and left ventricular ejection fraction (LVEF) by transthoracic echocardiogram within 7 days before and after PVL closure. We identified patients as non-responders if there was moderate to severe residual mitral regurgitation. t-Test was used for continuous variables and Fisher exact test was used mortality. Results: Overall, the mean CW TVI was markedly reduced by PVL closure (93±14 vs. 58±5cm, p<0.02). The E velocity also decreased after closure (3.1±0.4 vs. 1.9±0.1m/sec, p<0.04). LVEF, however, was reduced after PVL closure (62%±2 vs. 53%±1.5, p<0.02). Among non-responders (34/148 patients), there was no significant difference between the CW and E velocity before and after the procedure (CW TVI: 96±16 vs. 83+13cm, E velocity: 2.5±0.5 vs. 2.3±0.3m/sec, p=NS). The estimated 5-year mortality of patients with no or mild residual mitral regurgitation was markedly lower compared to non-responders, 43% vs 71%, p<0.05. Conclusions: The flow dynamics across the mitral valve immediately after PVL closure may correlate with long term clinical outcomes. Real time assessment of flow by transesophageal echocardiogram can be used to guide the extent of PVL closure required to change the long term clinical outcomes. Further validation and prospective studies are required.

Introduction: Presence of subclinical left ventricle (LV) dysfunction may influence outcomes after percutaneous mitral balloon valvotomy (PMBV), but cannot be detected by conventional echocardiography. Hypothesis: Preprocedure LV global longitudinal strain (GLS) by speckle tracking TTE detects subclinical LV dysfunction and predicts long-term outcome after successful PMVB. Methods: Consecutive patients undergoing PMBV between 2003-2011 who had comprehensive baseline TTE were included. Patients with suboptimal immediate results (repeat PMBV or mitral surgery within first 6 months) and those with suboptimal TTE strain were excluded. LV strain was analyzed with commercial software (Syngo VVI), and GLS averaged from 18 segments. The primary end point was all-cause mortality. Secondary end point was the composite of death and mitral valve reintervention. Results: Of 110 patients screened, 29 (26%) had unsuitable strain imaging, and 8 (7%) had poor immediate results, leaving 73 in the final cohort. Median follow-up was 3.7 years (interquartile range 1.3-7.2). There were 10 deaths (14%) and 25 late mitral valve interventions (34%). Univariate predictors of death were GLS, age, EF, stroke volume, pulmonary artery pressure, mitral valve area and coronary artery disease. In a multivariate Cox model, GLS was the strongest predictor of death after adjustment for age [HR=1.40 (1.09-1.84), P=0.008]. For the composite endpoint, GLS, mitral valve gradient, and invasively mean left atrial pressure were univariate predictors of death or reintervention. At multivariate analysis, GLS was the sole predictor of events [HR=1.17 (1.01-1.34), P=0.03]. Event-free survival is shown in figure. Intra and inter observer intra-class correlation for strain analysis was 0.87 (0.66-0.96) and 0.84 (0.53-0.95), respectively. Conclusions: GLS is a powerful predictor of long-term outcome after PMVB and appears to have an incremental prognostic value over traditional parameters.

Objective Bioprosthetic valves are being used with increased frequency for valve replacement, with controversy regarding risk:benefit ratio compared with mechanical valves in younger patients. However, prior studies have been too small to provide comparative estimates of less common but serious adverse events such as infective endocarditis. We aimed to compare the incidence of infective endocarditis between bioprosthetic valves and mechanical valves. Methods We searched PubMed, Cochrane, EMBASE, Scopus and Web of Science from inception to April 2018 for studies comparing left-sided aortic and mitral bioprosthetic to mechanical valves for randomised trials or observational studies with propensity matching. We used random-effects model for our meta-analysis. Our primary outcome of interest was the rate of infective endocarditis at follow-up. Results 13 comparison groups with 43 941 patients were included. Mean age was 59±7 years with a mean follow-up of 10.4±5.0 years. Patients with bioprosthetic valves had a higher risk of infective endocarditis compared with patients receiving mechanical valves (OR 1.59, 95% CI 1.35 to 1.88, p<0.001) with an absolute risk reduction of 9 per 1000 (95% CI 6 to 14). Heterogeneity within the included studies was low (I2=0%). Exclusion of the study with maximum weight did not change the results of the analysis (OR 1.57, 95% CI 1.14 to 2.17, p=0.006). A meta-regression of follow-up time on incidence of infective endocarditis was not statistically significant (p=0.788) indicating difference in follow-up times did not alter the pooled risk of infective endocarditis. Conclusions Bioprosthetic valves may be associated with a higher risk of infective endocarditis. These data should help guide the discussion when deciding between bioprosthetic and mechanical valves in individual patients.

Objective A subset of patients at the time of transcatheter mitral valve repair (TMVR) will have normal left atrial pressure (LAP) (<13 mm Hg) despite having severe mitral regurgitation (MR). The goal of this study was to determine clinical characteristics and outcomes in patients with normal LAP undergoing TMVR. Methods A single-centre retrospective cohort of consecutive patients who underwent transcatheter edge-to-edge mitral valve clip and continuous LAP monitoring between 5/1/2014 and 5/1/2018 was analysed. One-year mortality was compared by Kaplan–Meier survival curves. Multivariable analysis was performed to identify predictors of normal LAP and 1 year mortality. Results Of the 204 patients undergoing TMVR, 65% were men and the mean age was 81. Of these patients, 31 (15%) had normal LAP (mean LAP 10.5 mm Hg, mean V wave 16.5 mm Hg) and 173 had elevated LAP (mean LAP 19 mm Hg, mean V wave 32.5 mm Hg). The prevalence of severe MR was not different between groups, although the normal LAP group had significantly lower effective regurgitant orifice area and regurgitant volume. Other notable baseline characteristics including prior cardiac surgery, atrial fibrillation, hypertension, diabetes, congestive heart failure, body mass index, mechanism of MR and ejection fraction were similar between groups. However, there was an increased prevalence of chronic lung disease (CLD) (45.2% vs 17.3%, p<0.001) in the normal LAP group. On multivariate analysis, the only significant predictor of normal LAP was the presence of CLD (OR 4.79 (1.83–12.36), p=0.001) and 1-year mortality was significantly higher in the normal LAP group (32.3% vs 12.7%, p=0.006). After adjustment for comorbidities, normal LAP was no longer a predictor of 1-year mortality (RR 1.62 (0.64–4.06), p=0.32); however, CLD (RR 3.44 (1.37–8.67), p=0.01) remained a statistically significant predictor. Conclusion Normal LAP at the time of TMVR is associated with a higher incidence of CLD which independently predicts increased 1-year mortality. In patients with CLD and apparently severe MR, measurement of LAP may help identify those with lower likelihood of benefit from TMVR.