Abstract 15236: Valvuloarterial Impedance and Hypertension as Predictors of Syncope in Patients with Severe Aortic Stenosis

Abstract

Background: Syncope is one of the most serious symptoms in severe aortic valve stenosis (AS). The aim of this study was to assess the impact of clinical characteristics and echocardiographic parameters, including valvuloarterial impedance (Zva), on syncope in severe AS. The Zva is a new index of global left ventricular (LV) afterload, which is obtained by dividing the sum of valvular and vascular loads by the stroke volume index.

Methods and results: A total of 100 patients with severe AS (aortic valve area, AVA < 1 cm²) and preserved LV ejection fraction (≥50%) were included in the study. The 100 AS patients were divided into two groups according to a history of syncope, patients with syncope (n=30) and without syncope (n=70). In clinical characteristics, patients with syncope had a higher prevalence of hypertension compared with those without syncope (p=0.036). There was no difference in age, gender, body mass index and the prevalence of diabetes and hyperlipidemia between the two groups. In echocardiographic data, LV mass index, relative wall thickness, left atrial volume index, LVEF, the ratio of the early diastolic transmitral flow velocity to mitral annular velocity (E/e’) and AVA were similar in the two groups. However, stroke volume index was lower (35.5 vs. 40.9 ml/m², p=0.038) and Zva was higher (5.3 vs. 4.4 mmHg/ml/m², P=0.002) in patients with syncope than in those without syncope. On multivariable analysis, hypertension and Zva were found to be significantly predictive of syncope (Table 1).The receiver operating characteristic curve assessed Zva to detect syncope. The optimal cutoff point for syncope was 4.50 mmHg/ml/m²(area under the curve 0.70). The sensitivity and specificity of this model were 83% and 53%, respectively.

Conclusion: The present study shows that higher Zva and history of hypertension predict syncope in patients with severe AS. Zva may be useful to identify patients with an increased risk of syncope and improve clinical decision making in AS.