Active and passive cardiac indexes as complementary predictors of outcomes after left ventricular assist device implantation.

BACKGROUND

Goals of left ventricular assist device (LVAD) therapy include low rates of right ventricle (RV) failure and favorable survival outcomes. However, conventional metrics often fail to capture its physiologic complexity. We evaluated the prognostic utility of the active cardiac index (ActCI) and passive cardiac index (PasCI), which reflect cardiac output driven by active RV contractility and passive venous return, respectively.

METHODS

We retrospectively analyzed 399 patients who underwent primary continuous-flow LVAD implantation at Mayo Clinic (2007 to 2023). Pre-LVAD ActCI and PasCI were calculated from preoperative right heart catheterization data. Optimal thresholds predicting survival were identified using spline analysis. Outcomes were evaluated using Kaplan-Meier curves, multivariable Cox models, and concordance statistics. Comparisons were made against the pulmonary artery pulsatility index and RV stroke work index.

RESULTS

A high ActCI >0.903 was associated with better survival (hazard ratio, 0.71; P = .019) whereas PasCI >0.778 predicted worse survival (hazard ratio, 1.39; P = .022). Low ActCI was associated with increased postoperative RV failure (11.3% vs 4.9%; P = .018), dialysis (27.8% vs 11.7%; P < .001), hepatic dysfunction (21.1% vs 8.3%; P < .001), and in-hospital mortality (14.3% vs 5.6%; P = .004). Conversely, higher PasCIs portend increased rates of postoperative dialysis (28.6% vs 11.3%; P < .001), respiratory failure (28.6% vs 19.5%; P = .042), hepatic dysfunction (21.8% vs 7.9%; P < .001), gastrointestinal bleeding (44.4% vs 32.3%; P = .019), and in-hospital mortality (12.0% vs 6.8%; P = .076).

CONCLUSIONS

ActCI and PasCI independently predict survival and RV failure after LVAD. These indices outperform pulmonary artery pulsatility index and RV stroke work index and may enhance pre-LVAD risk stratification and help balance decisions for heart transplantation.