P1371 The effect of ideal BSA in patients with low-flow, low-gradient severe aortic stenosis

Abstract

Abstract INTRODUCTION The current obesity epidemic has an impact on calculated BSA, significantly increasing the calculated BSA from what the ideal BSA would be if based on a patient’s ideal body weight. PURPOSE To determine the effect of ideal BSA on AV area index in patients with low-flow, low-gradient severe aortic stenosis and normal left ventricular function. METHODS Our ECHO database was searched for all patients with an LVEF >50%, a mean aortic gradient of <40 mmHg, an AV area <1.00cm2, AVA index <0.60cm2/m2 and SV index <35ml/m2. Patients with atrial fibrillation, mechanical and bioprosthetic valves, any valve repair, HOCM, Amyloidosis, more than mild aortic regurgitation, moderate mitral regurgitation, any wall motion abnormality despite normal LVEF, Pacemaker or ICD or a moderate pericardial effusion were excluded. Ideal weight was calculated using the Devine formula = Constant + 2.3 x [height in inches-60], where constant= 50Kg in males and 45.5Kg in females). Body surface area in m2 was calculated using the formula = [√ (height in cm x weight in kg)/3600]. The paired t-test was used to determine differences between means and the Fisher’s exact test was used to determine differences between proportions. A p value of <0.05 was considered significant. RESULTS There were 73 females (mean age 76.2 ± 11.3 years, mean AV gradient 27.2 ± 7.4 mmHg, mean AVA 0.82 ± 0.11 cm2 and mean LVEF of 64.9 ± 5.4%) and 55 males (mean age 76.1 ± 9.8 years, mean AV gradient 29.9 ± 7.2 mmHg, mean AVA 0.85 ± 0.11 cm2and mean LVEF of 62.2 ± 5.7%). Other important variables are seen in table 1. Based on the corrected ideal BSA there were 0 of 55 male patients who were re-assigned to the moderate AS category, compared to 25 of 73 (34.2%) female patients (P < 0.0001, Fisher’s exact test). CONCLUSIONS Use of the corrected ideal BSA has no effect on the hemodynamic diagnosis of low-flow, low gradient, normal LVEF severe aortic stenosis in males, but has a significant effect of the same diagnosis in females. It is therefore recommended that ideal body weight and ideal BSA be used when calculating AVA index in female patients suspected of low-flow, low-gradient severe aortic stenosis with normal ventricular function. Weight(M) Weight(F) BSA(M) BSA(F) AVAI(M) AVAI(F) SVI(M) SVI(F) Actual 82.6 ± 12.5 70.1 ± 13.5 1.95 ± 0.15 1.71 ± 0.16 0.44 ± 0.06 0.48 ± 0.07 25.9 ± 4.9 23.9 ± 5.1 Ideal 67.5 ± 6.8 49.7 ± 5.4 1.79 ± 0.13 1.47 ± 0.11 0.48 ± 0.07 0.56 ± 0.08 28.3 ± 5.5 27.7 ± 6.3 P value <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 (M)=male, (F)=female, weight in kg, BSA in m2, AVAI in cm2/m2, SVI in ml/m2.