Cardiac power output or stroke volume index to predict outcome in transcatheter aortic valve implantation

Norman Mangner (Dresden)1, F. Woitek (Dresden)1, S. Haussig (Dresden)1, L. Crusius (Dresden)1, P. Kiefer (Leipzig)2, D. Holzhey (Wuppertal)3, A. Linke (Dresden)1

1Herzzentrum Dresden GmbH an der TU Dresden Klinik für Innere Medizin, Kardiologie und Intensivmedizin Dresden, Deutschland; 2Herzzentrum Leipzig - Universität Leipzig Universitätsklinik für Herzchirurgie Leipzig, Deutschland; 3Helios Universitätsklinikum Wuppertal - Herzzentrum Klinik für Herz- und Thoraxchirurgie Wuppertal, Deutschland


Background: Cardiac power output (CPO) has been suggested to predict the outcome after transcatheter aortic valve implantation (TAVI). So far, studies used non-invasive estimated CPO but not CPO calculated from invasive hemodynamics and adjusting for stroke volume index (SVI) has not been done. We investigated the impact of an invasively measured CPO on the outcome of patients undergoing TAVI.

Methods: Out of 1823 patients undergoing TAVI between 2006 and 2014, 1253 patients had available hemodynamic data from right and left heart catheterization. The median CPO was 0.71 W and patients were divided into CPO ≤0.71 W (low CPO, n=628) and CPO >0.71 W (high CPO, n=625). The primary outcome was 3-year mortality.

Results: Compared with high CPO, low CPO patients were older, less often male and had a higher burden of comorbidities (all p<0.05). This led to significantly higher STS-PROM in low compared to high CPO (7.6% (IQR 4.9; 11.9) vs. 5.2% (3.5; 8.5), p<0.001). Left ventricular ejection fraction (LV-EF, 54% (IQR 40; 63) vs. 60% (IQR 53; 67), p     <0.001) and SVI (33 ml/m² (IQR 27; 42) vs. 39 ml/m² (IQR 31; 46), p<0.001) were lower in low CPO; however, the correlation between CPO, LV-EF and SVI was significant but weak (r=0.30 for CPO/LV-EF and r=0.24 for CPO/SVI, both p<0.001).

CPO was not associated with VARC-defined peri-interventional complications (all p>0.05). The thirty-day mortality was numerically higher in low compared with high CPO without reaching statistical significance (46/628 (7.3%) vs. 31/624 (5.0%), p=0.083).

The 3-year mortality was significantly higher in low compared with high CPO (34.2% vs. 24.4%, log-rank p<0.001). In a Cox regression analysis adjusting for age, sex, STS-PROM, LV-EF, SVI and CPO, only STS-PROM (HR per 1% increase 1.05 (95%-CI 1.03; 1.06), p<0.001) and CPO (HR for 0.1 W increase 0.94 (95%-CI 0.90; 0.99), p=0.023) remained independent predictors for 3-year mortality.

Conclusion: TAVI can be safely performed in patients with low and high CPO measured by invasive hemodynamics; however, low CPO characterizes a patient cohort with an increased mortality risk during a 3-year follow-up and provides superior prognostication over echocardiography-derived SVI.

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