Introduction:

Contrast-enhanced cardiac CT, routinely performed prior to transcatheter aortic valve implantation (TAVI), allows assessment of cardiac morphology and function. We assesed right ventricular funtion in CT as a predictor of survival following TAVI.

Methods:

500 consecutive patients referred for CT assessment of aortic root anatomy prior to TAVI were screened for inclusion in this analysis. All CT data sets were acquired using a third generation dual source system. For assessment of aortic root anatomy, acquistions were acquired using ECG-gated retrospective spiral acquisition and multiphase reconstructions in 10% increments of the cardiac cycle were rendered (slice thickness 0.75, increment 0.4 mm). Right ventricular endocardial contours were automatically traced by a dedicated software (syngo. via, Siemens Healthineers, Forchheim, Germany) throughout the cardiac cycle and manually adjusted if required. Global right ventricular function parameters (end-diastolic and end-systolic volumes, stroke volume and ejection fraction) were derived by volumetric assessment. Furthermore, similar to echocardiographic 4-chamber view, systolic excursion of the tricuspid annular plane (TAPSE) was assessed in CT.

Results:

Out of 500 patients, 439 patients (mean age 80 ± 6 years, 56% males, mean LV ejection fraction 59±18% and Log EuroScore 23±14%) were included in this analysis (61 patients were excluded due to poor CT image quality or missing outcome data). Previous cardiac surgery had been performed in 15% of the patients, 50% had obstructive CAD with previous interventional or surgical revascularisation and 18% had a previous acute coronary syndrome. One-year survival was 83 % (366/439 patients). Parameters of right ventricular function were as follows: mean RVEDV 103±26 ml, mean RVESV 63±22 ml, mean RV ejection fraction 39±10%, mean RV stroke volume 77±34 ml and mean RV cardiac ouput 5.2±1.6 L/min.  Median TAPSE was 17 mm (IQR 14; 22 mm). RV ejection fraction and stroke volume showed a positive significant correlation with TAPSE (r=0.8 and 0.7, respectively, p<0.0001) and negative correlation to RVEDV and RVESV (r=-0.2 and -0,5, respectively, p<0.0001). Cluster analysis of multiple RV-function surrogate parameters identified a group of patients with higher 1-year mortality, with TAPSE identified as the strongest predictor of 1 year survival with a cut-0ff of >12.1 mm associated with an OR 0f 0.34 (95% CI 0.19 to 0.6).

Conclusion:

Assessment of right ventricular function using functional CT data sets is feasible and allows risk stratification of patients following TAVI. Among RV functional parameters, assessment ot TAPSE in CT is the strongest predictor of 1-year survival following TAVI.