Transaortic flow is associated with symptom-driven aortic valve replacement in aortic stenosis

To assess the association of transaortic flow-rate (TFR) with symptom-driven aortic valve replacement (AVR) in asymptomatic patients with moderate to severe aortic stenosis (AS). PRIMID was a prospective, multi-centre observational study. Patients with asymptomatic moderate to severe AS underwent transthoracic echocardiography (TTE), cardiopulmonary exercise testing and stress cardiovascular magnetic resonance (CMR) imaging. TFR was calculated as stroke volume divided by left ventricular ejection time. Patients were followed-up for a minimum of one-year initially. The primary outcome was symptom-driven AVR. Long-term follow-up data was obtained through electronic health records. The secondary outcome was long-term major adverse cardiovascular events (MACE) defined as cardiovascular mortality and hospitalisation with heart failure, myocardial infarction, syncope or arrhythmia. We included 171 individuals: mean age 66.21±3.43 years, 76% male, mean aortic valve area 1.12±0.31cm2. At one-year (median: 366 days, IQR: 312-437) there were 47 symptom-driven AVRs. Over long-term follow-up of 6.52 years (IQR: 5.23-7.22), there were 95 symptom-driven AVRs and 47 MACE events. In multivariable models, TFR was associated with symptom-driven AVR at one-year (HR: 0.12, 95%CI: 0.04-0.39, p<0.01), independent of a positive exercise tolerance test and CMR-measured myocardial perfusion reserve. Age (HR: 1.05, 95%CI: 1.01-1.10, p=0.01) and NT-pro-BNP (HR: 1.46, 95%CI: 1.12-1.89, p<0.01) predicted long-term MACE events, while TFR did not (HR: 0.48, 95%CI: 0.13, 1.74, p=0.26). TFR is independently associated with symptom-driven AVR in initially asymptomatic individuals with moderate to severe AS at one-year. TFR may be useful in identifying individuals who will undergo symptom-driven intervention, but prospective randomised data are needed to assess clinical utility.