Detection of progression of asymptomatic severe aortic stenosis using Apple Watch–estimated maximal oxygen consumption (VO₂ max): a case report

Symptomatic aortic stenosis (AS) constitutes a class I indication for aortic valve intervention, either by surgical or transcatheter aortic valve replacement (TAVR). Progressive AS can reduce maximal oxygen consumption (MVO₂), yet this parameter is not routinely evaluated in clinical practice.

We present a case of a 68-year-old with hypertension and hyperlipidaemia, initially diagnosed with moderate AS [aortic valve area (AVA) 1.3 cm², mean gradient 23 mmHg, peak velocity 3.2 m/s]. He was asymptomatic and maintained a high level of physical activity, including treadmill running. Over the course of 3 years, the patient used an Apple Watch® to monitor estimated VO₂ max. Despite stable exercise tolerance, his recorded VO₂ max decreased progressively from 36 to 26 mL/kg/min. Concerned by the trend, he sought our evaluation. Repeat echocardiography showed severe AS (AVA 0.6 cm2, mean gradient 43 mmHg, peak velocity 4.29 m/s) with preserved left ventricular ejection fraction (LVEF 60%–65%). The patient subsequently underwent TAVR with a 26 mm Edwards Lifesciences Sapien 3 Ultra Valve®. At 1-year follow-up, his Apple Watch–derived VO₂ max improved to 41 mL/kg/min. Echocardiography confirmed a well-seated prosthesis with a mean gradient of 9 mmHg.

This case illustrates the potential utility of consumer wearable technology (Apple Watch) for detecting progressive asymptomatic AS using estimated VO₂ max feature. Continuous tracking of estimated VO₂ max may serve as an adjunct parameter to guide timing of intervention in selected patients.