Abstract 12566: Use Of Aortic Valve Area Index By Actual Body Weight Overestimates Aortic Stenosis Severity In Obese Patients

Abstract

Introduction: Guidelines recommend indexing aortic valve area (AVA) to body surface area in grading the severity of aortic stenosis (AS), which overestimates severity in obese patients. The indexing of AVA to ideal or adjusted body weight has not been explored. Hypothesis: We hypothesized that using actual body weight compared to ideal or adjusted body weight in obese patients would result in overestimation of the severity of AS using AVAi. Methods: We conducted retrospective chart review on 305 individuals who received a transthoracic echocardiogram (TTE) at Tufts Medical Center from June 2021 to Sept. 2021 with AVA <1.5cm 2 . We selected 73 subjects with moderate AS (AVA 1-1.5cm 2 ). These subjects were divided into an overweight and obese group (BMI > 25; n = 56) and a normal weight group (BMI 18-24.9; n = 17). We recorded baseline characteristics and TTE data. AVAi was calculated with actual, ideal, and adjusted body weight. The primary outcome was reclassification, defined as a change in severity from severe AS to mild or moderate AS after recalculating AVAi using adjusted or ideal body weight. Results: The overweight and obese group was significantly younger (age 74.4±11.2 versus 80.7±5.7 years, P=0.018) with higher BSA (2.0±0.2 versus 1.7±0.2, P=0.010) compared to the normal weight group. The recorded median AVAi was 0.61 with interquartile range(IQR) of 0.17. There was no significant difference in blood pressure, ejection fraction, AVA, peak aortic velocity, peak gradient, and mean gradient. After calculating AVAi with adjusted and ideal body weight, 18 patients in the overweight and obese group were reclassified to a lower grade of AS based on AVAi (median AVAi 0.58, IQR 0.17), compared with 0 reclassifications in the normal weight group (0.67, 0.18). Patients who were reclassified had a significantly smaller AVA compared to patients who were not reclassified (1.09±0.11 versus 1.23±0.19 cm 2 , P<0.001), while no differences were observed in peak gradient, mean gradient, and peak velocity. Conclusions: Using actual body weight to calculate AVAi in overweight and obese patients can lead to overestimation of AS severity. Further research is needed to investigate the optimal indexing strategy for AVAi and the effects of classification on cardiovascular outcomes.