Detection of Progression of Asymptomatic Severe Aortic Stenosis using Apple Watch- Estimated Maximal Oxygen Consumption (VO2 max): A Case Report

Structured Abstract Background 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. Case Summary We present a case of a 68-year-old with hypertension and hyperlipidemia, initially diagnosed with moderate AS (Aortic valve area [AVA] 1.3 cm^2, 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 three years, the patient used an Apple Watch ® to monitor estimated VO2 max. Despite stable exercise tolerance, his recorded VO2 max decreased progressively from 36 mL/kg/min 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 one-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. Discussion 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.