Temporal Trends in the Utilization of Aortic Valve Replacement for Symptomatic Severe Aortic Stenosis from 2000-2017: Insights from a Multi-Centered Study

Introduction: Despite the rapid growth of aortic valve replacement (AVR) for aortic stenosis (AS), studies have suggested that symptomatic severe AS remains undertreated. Hypothesis: The growth in patients with an indication for AVR has outpaced the number of AVRs performed. Methods: We identified patients with severe AS (aortic valve area <1cm 2 ) on transthoracic echocardiograms from 2000-2017 at two large academic medical centers. Natural language processing (NLP) models were developed and validated to identify symptoms consistent with severe AS, and patients were classified based on ACC/AHA clinical guideline indications for AVR. Patients were divided into groups based on mean aortic valve gradient (mAVG≥ 40 or <40mmHg) and left ventricular ejection fraction (LVEF≥50% or <50%). Utilization of AVR (transcatheter aortic valve implantation [TAVI] or surgical aortic valve replacement [SAVR]) in patients with a clinical indication was examined over time, and clinical predictors of AVR were identified via multivariate logistic regression. Results: A total of 10,795 AS patients were included in this analysis, of whom 6,150 (57%) had an indication or potential indication for AVR and 2,976 (48%) received AVR. The frequency of AVR varied by AS subtype (HG-NEF: 69%, HG-LEF: 53%, LG-NEF: 32%, LG-LEF: 38%, p<0.001). The adoption of TAVI contributed to the growth in AVR volume over time, however there has been a parallel rise in the number of patients with an indication for AVR (Figure). In patients with a class I indication for AVR, younger age, coronary artery disease, smoking history, higher hematocrit, outpatient index TTE, and LVEF≥0.5 were independently associated with an increased likelihood of receiving an AVR. Conclusions: Over an 18-year study period, the proportion of patients with an indication for AVR who do not receive AVR has remained significant despite the rapid growth of AVR volumes.