The Association of the Pulmonary Artery Pulsatility Index and Right Ventricular Function after Cardiac Surgery.

Background: The pulmonary artery pulsatility index (PAPi) has been shown to correlate with right ventricular (RV) failure in patients with cardiac disease. However, the association of PAPi with right ventricular function following cardiac surgery is not yet established. Methods: PAPi and other hemodynamic variables were obtained postoperatively for 959 adult patients undergoing cardiac surgery. The association of post-bypass right ventricular function and other clinical factors to PAPi was evaluated using linear regression. A propensity-score matched cohort for PAPi ≥ 2.00 was used to assess the association of PAPi with postoperative outcomes. Results: 156 patients (16.3%) had post-bypass right ventricular dysfunction defined by visualization on transesophageal echocardiography. There was no difference in postoperative PAPi based on right ventricular function (2.12 vs. 2.00, p=0.21). In our matched cohort (n = 636), PAPi < 2.00 was associated with increased incidence of acute kidney injury (23.0% vs 13.2%, p < 0.01) and ventilator time (6.0 hours vs 5.6 hours, p=0.04) but not with 30-day mortality or intensive care unit length of stay. Conclusion: In a general cohort of patients undergoing cardiac surgery, postoperative PAPi was not associated with postcardiopulmonary bypass right ventricular dysfunction. A postoperative PAPi < 2 may be associated with acute kidney injury.

Postoperative Pulmonary Artery Pulsatility Index Improves Prediction of Right Ventricular Failure After Left Ventricular Assist Device Implantation.

OBJECTIVES: This study evaluated whether the postoperative pulmonary artery pulsatility index (PAPi) is associated with postoperative right ventricular dysfunction after durable left ventricular assist device (LVAD) implantation. DESIGN: Single-center retrospective observational cohort study. SETTING: The University of Kansas Medical Center, a tertiary-care academic medical center. PARTICIPANTS: Sixty-seven adult patients who underwent durable LVAD implantation between 2017 and 2019. INTERVENTIONS: All patients underwent open cardiac surgery with cardiopulmonary bypass under general anesthesia with pulmonary artery catheter insertion. MEASUREMENTS AND MAIN RESULTS: Clinical and hemodynamic data were collected before and after surgery. The Michigan right ventricular failure risk score and the European Registry for Patients with Mechanical Circulatory Support score were calculated for each patient. The primary outcome was right ventricular failure, defined as a composite of right ventricular mechanical circulatory support, inhaled pulmonary vasodilator therapy for 48 hours or greater, or inotrope use for 14 days or greater or at discharge. Thirty percent of this cohort (n = 20) met the primary outcome. Preoperative transpulmonary gradient (odds ratio [OR] 1.15, 95% CI 1.02-1.28), cardiac index (OR 0.83, 95% CI 0.71-0.98), and postoperative PAPi (OR 0.85, 95% CI 0.75-0.97) were the only hemodynamic variables associated with the primary outcome. The addition of postoperative PAPi was associated with improvement in the predictive model performance of the Michigan score (area under the receiver operating characteristic curve 0.73 v 0.56, p = 0.03). An optimal cutoff point for postoperative PAPi of 1.56 was found. CONCLUSIONS: The inclusion of postoperative PAPi offers more robust predictive power for right ventricular failure in patients undergoing durable LVAD implantation, compared with the use of existing risk scores alone.

Prospective Evaluation of a Multibeat Analysis Cardiac Index Estimation in Patients With Cardiogenic Shock.

OBJECTIVES: The decision algorithm for managing patients in cardiogenic shock depends on cardiac index (CI) estimates. Cardiac index estimation via thermodilution (CI-TD) using a pulmonary artery catheter is used commonly for obtaining CI in these patients. Minimally invasive methods of estimating CI, such as multibeat analysis (CI-MBA), may be an alternative in this population. DESIGN: A prospective, observational study. SETTING: Cardiac intensive care unit. PARTICIPANTS: Twenty-two subjects in cardiogenic shock provided 101 paired CI measurements. INTERVENTIONS: Measurements were obtained concomitantly by intermittent CI-TD and CI-MBA (Argos Cardiac Output Monitor; Retia Medical, Valhalla, NY). For each CI-TD, CI-MBA estimates were averaged over 1 minute to provide paired values. Bland-Altman and 4-quadrant analyses were performed by plotting changes between successive CI measurements (ΔCI) from each of the 2 methods. Concordance was calculated as a percentage using ΔCI data points from the 2 methods, outside an exclusion zone of 15%. MEASUREMENTS AND MAIN RESULTS: The correlation coefficient between CI-MBA and CI-TD was 0.78 across patients. Mean CI-TD was 2.19 ± 0.46 L/min/m2 and mean CI-MBA was 2.38 ± 0.59 L/min/m2. The mean difference between CI-MBA and CI-TD (bias ± SD) was 0.20 ± 0.47 L/min/m2, and the limits of agreement were -0.72 to 1.11 L/min/m2. The percentage error was 40.0%. The concordance rate was 94%. A secondary analysis of a subgroup of patients during periods of arrhythmia demonstrated a similar accuracy of performance of CI-MBA. CONCLUSIONS: Cardiac index-MBA is not interchangeable with CI-TD. However, CI-MBA provides reasonable correlation and clinically acceptable trending ability compared with CI-TD. Cardiac output-MBA may be useful in trending changes in CI in patients with cardiogenic shock, especially in those whose pulmonary artery catheterization placement carries a high risk or is unobtainable.