Left Ventricular Stroke Work Index as a Predictor of Aortic Stenosis After Transcatheter Aortic Valve Implantation

Evaluation of left ventricular (LV) myocardial contractility to predict outcome in aortic stenosis (AS) is challenging because global longitudinal strain (GLS) does not take afterload into account. We thus tested prognostic value of an echocardiographic index of LV external work, stroke work index (SWI) in AS patients undergoing transcatheter aortic valve implantation (TAVI).

We evaluated 1583 patients who underwent TAVI from database of a multicenter retrospective study. As an index of LV external work, echocardiographic LV SWI was calculated as 0.0136 × [stroke volume index × (mean aortic pressure + mean transvalvular pressure gradient-LV end-diastolic pressure)] [g × min/m²], where LV end-diastolic pressure was estimated as 4.9 + (0.62 × E/e') [mmHg]. GLS data was available in 902 patients. Primary endpoint was defined as cardiac death or worsening heart failure.

During a median follow-up period of 725 days, 262 patients experienced primary endpoint. Kaplan-Meyer analysis showed that patients having lower LV SWI had lower event-free survival. Furthermore, Cox regression analysis showed that LV SWI was associated with primary endpoint independently of other clinically relevant factors. When influence of LV SWI on outcome was tested in preserved and reduced GLS groups respectively, LV SWI discriminated event-free survival in patients showing reduced GLS.

Reduced LV SWI before TAVI was associated with poorer outcomes in AS patients. Furthermore, combined assessment of LV SWI and GLS is expected to improve prognostic risk stratification in AS patients undergoing TAVI.