Differences in Clinical and Echocardiographic Profiles and Outcomes of Patients With Atrial Fibrillation Versus Sinus Rhythm in Medically Managed Severe Aortic Stenosis and Preserved Left Ventricular Ejection Fraction

The impact of atrial fibrillation on prognosis in aortic stenosis

BACKGROUND

Atrial fibrillation (AF) and aortic stenosis (AS) are both highly prevalent and often coexist. Various studies have focused on the prognostic value of AF in patients with AS, but rarely considered left ventricular (LV) diastolic function as a prognostic factor.

OBJECTIVE

To evaluate the prognostic impact of AF in patients with AS while correcting for LV diastolic function.

METHODS

Patients with first diagnosis of significant AS were selected and stratified according to history of AF. The endpoint was all-cause mortality.

RESULTS

In total, 2849 patients with significant AS (mean age 72 ± 12 years, 54.8% men) were evaluated, and 686 (24.1%) had a history of AF. During a median follow-up of 60 (30-97) months, 1182 (41.5%) patients died. Ten-year mortality rate in patients with AF was 46.8% compared to 36.8% in patients with sinus rhythm (SR) (log-rank P < 0.001). On univariable (HR: 1.42; 95% CI: 1.25-1.62; P < 0.001) and multivariable Cox regression analysis (HR: 1.19; 95% CI: 1.02-1.38; P = 0.026), AF was independently associated with mortality. However, when correcting for indexed left atrial volume, E/e' or both, AF was no longer independently associated with all-cause mortality.

CONCLUSION

Patients with significant AS and AF have a reduced survival as compared to patients with SR. Nonetheless, when correcting for markers of LV diastolic function, AF was not independently associated with outcomes in patients with significant AS.

ABCDEG Stress Echocardiography in Aortic Stenosis

Rest and stress echocardiography (SE) plays a pivotal role in the evaluation of valvular heart disease. The use of SE is recommended in valvular heart disease when there is a mismatch between resting transthoracic echocardiography findings and symptoms. In aortic stenosis (AS), rest echocardiographic analysis is a stepwise approach that begins with the evaluation of aortic valve morphology and proceeds to the measurement of the transvalvular aortic gradient and aortic valve area (AVA) using continuity equations or planimetry. The presence of the following three criteria suggests severe AS: AVA < 1.0 cm2, a peak velocity > 4.0 m/s, or a mean gradient > 40 mmHg. However, in approximately one in three cases, we can observe a discordant AVA < 1 cm2 with a peak velocity < 4.0 m/s or a mean gradient <40 mmHg. This is due to reduced transvalvular flow associated with LV systolic dysfunction (LVEF < 50%) defined as "classical" low-flow low-gradient (LFLG) AS or normal LVEF "paradoxical" LFLG AS. SE has an established role in evaluating LV contractile reserve (CR) patients with reduced LVEF. In classical LFLG AS, LV CR distinguished pseudo-severe AS from truly severe AS. Some observational data suggest that long-term prognosis in asymptomatic severe AS may not be as favorable as previously thought, offering a window of opportunity for intervention prior to the onset of symptoms. Therefore, guidelines recommend evaluating asymptomatic AS with exercise stress in physically active patients, particularly those younger than 70 years, and symptomatic classical LFLG severe AS with low-dose dobutamine SE. A comprehensive SE assessment includes evaluating valve function (gradients), the global systolic function of the LV, and pulmonary congestion. This assessment integrates considerations of blood pressure response, chronotropic reserve, and symptoms. StressEcho 2030 is a prospective, large-scale study that employs a comprehensive protocol (ABCDEG) to analyze the clinical and echocardiographic phenotypes of AS, capturing various vulnerability sources which support stress echo-driven treatment strategies.

Prognostic impact of echocardiographic mean transvalvular gradients in patients with aortic stenosis and low flow undergoing transcatheter aortic valve implantation

BACKGROUND

Blunted left ventricular hemodynamics reflected by a low stroke volume index (SVI) ≤35 mL/m² body surface area (low flow [LF]) in patients with severe aortic stenosis (AS) are associated with worse outcomes even after correction of afterload by transcatheter aortic valve implantation (TAVI). These patients can have a low or high transvalvular mean pressure gradient (MPG). We investigated the impact of the pre-interventional MPG on outcomes after TAVI.

METHODS

Patients with LF AS were classified into those with normal (EF ≥ 50%; LF/NEF) or reduced ejection fraction (EF < 50%; LF/REF) and were then stratified according to an MPG < or ≥ 40 mmHg. Patients with SVI >35 mL/m² (normal flow; NF) served as controls.

RESULTS

597 patients with LF/NEF, 264 patients with LF/REF and 975 patients with NF were identified. Among all groups those patients with a low MPG were characterized by higher cardiovascular risk. In patients with LF/REF, functional improvement post-TAVI was less pronounced in low-MPG patients. One-year survival was significantly worse in LF AS patients with a low vs. high MPG (LF/NEF 16.5% vs. 10.5%, p = 0.022; LF/REF 25.4% vs. 8.0%, p = 0.002), whereas no differences were found in NF patients (8.7% vs. 10.0%, p = 0.550). In both LF AS groups, a low pre-procedural MPG emerged as an independent predictor of mortality.

CONCLUSIONS

In patients with LF AS, an MPG cut-off of 40 mmHg defines two patient populations with fundamental differences in outcomes after TAVI. Patients with LF AS and a high MPG have the same favorable prognosis as patients with NF AS.