Percent Increase in Aortic Pulsatility Index and Pulmonary Artery Pulsatility Index after Milrinone Infusion Predicts Escalation of Therapy and Mortality

Purpose We hypothesized that the change in hemodynamic values after milrinone infusion would predict clinical outcomes. Methods We reviewed 177 patients undergoing right heart catheterization and milrinone loading at our center between January 2013 and December 2018. Percent increase in aortic pulsatility index (piAPI) was calculated as 100 * (aortic pulsatility index after milrinone infusion - aortic pulsatility index prior to milrinone infusion)/aortic pulsatility index prior to milrinone infusion, and percent increase in pulmonary artery pulsatility index (piPAPI) was calculated as 100 * (pulmonary artery pulsatility index after milrinone infusion - pulmonary artery pulsatility index prior to milrinone infusion)/pulmonary artery pulsatility index prior to milrinone infusion. Cutpoints were determined by ROC analysis, and patients were stratified as follows: (1) High piAPI, High piPAPI; (2) High piAPI, Low piPAPI; (3) Low piAPI, High piPAPI; and (4) Low piAPI, Low piPAPI. Univariate and multivariate logistic and cox regression analyses were performed to determine association with escalation of therapy, defined as left ventricular assist device implantation, heart transplantation, or death. Results Cutpoints of 70% and 103% were determined for piAPI and piPAPI, respectively. Low piAPI, Low piPAPI was associated with escalation of therapy or death at 30-days (OR 2.42, 95% CI 1.16 - 5.3, p = 0.022; OR). In multivariate analysis, Low piAPI, Low piPAPI and High piAPI, Low piPAPI were predictors of the one-year endpoint (OR 8.95, 95% CI 2.43 - 43.1, p = 0.002; OR 6.87, 95% CI 1.79 - 34.16, p = 0.008; respectively). Grouping patients according to whether they possessed Low piAPI, Low piPAPI showed a greater hazard for the endpoint at 30-days and one-year (HR 2.27, 95% CI 1.24 - 4.15, p = 0.0076; HR 1.58, 95% CI 1.01 - 2.28, p = 0.014; respectively). Conclusion Low piAPI, Low piAPI status may indicate lower myocardial reserve and predict poorer outcomes.