Diastolic Stress Echocardiography Using the Six-Minute Walk Test in Asymptomatic Patients With Aortic Stenosis

Abstract

Diastolic stress echocardiography is useful in patients with heart failure with preserved ejection fraction (EF); however, its utility in asymptomatic patients with aortic stenosis (AS) remains unexplored. We investigated the value of diastolic stress echocardiography using a 6-minute walk test (6-MWT) in elderly AS patients. This retrospective observational study included 96 consecutive asymptomatic patients (82 years, 39.6% male) with at least moderate AS (mean pressure gradient (MPG) ≥ 20 mm Hg or aortic valve area < 1.5 cm²) and preserved left ventricular EF. All underwent diastolic stress echocardiography using the 6-MWT. Patients were classified into a post-exercise impaired relaxation pattern (pIR) and a post-exercise pseudo-normalised/restrictive pattern (pPN) groups, based on transmitral flow velocity post-6-MWT. The primary endpoint was the time to first occurrence of the composite endpoint (all-cause mortality, aortic valve replacement due to AS-related symptoms, and hospitalization for heart failure).22 patients (23%) changed from baseline IR pattern at rest to the pPN pattern after the 6-MWT.The pPN group demonstrated lower %predicted walking distance than the pIR group. Additionally, the pPN group exhibited greater dyspnea after the 6-MWT. During a median follow-up of 536 days (interquartile range, 106–720 days), 46 patients experienced AS-related events. Multivariable Cox regression analysis indicated that the pPN group was independently associated with increased event risk (hazard ratio: 5.37, p < 0.001). In conclusion, this study suggests that the diastolic stress echocardiography using the 6-MWT is useful for risk stratification in asymptomatic elderly AS patients.