Factors Associated with Success of Axillary Intra-aortic Balloon Pump as a Bridge to Transplant Strategy

Abstract

Introduction Several studies have shown lack of benefit of intra-aortic balloon pump (IABP) in the setting of ST-elevation myocardial infarction and cardiogenic shock. However, IABP continues to be used as mechanical circulatory support for bridge to cardiac transplant in patients with acute-on-chronic heart failure. We conducted this study to analyze characteristics that predict successful bridge to transplant with IABP. Methods We did a single-center retrospective analysis of all patients that received percutaneously inserted axillary IABP as BTT from November 2007 to February 2018. Baseline hemodynamic parameters were assessed by right heart catheterization reports and echocardiograms prior to the implantation of IABP. We calculated left ventricular cardiac power output (W) as mean arterial pressure x cardiac output/451. Death on IABP support was defined as any death occurring while on the waitlist for cardiac transplant and on IABP support. We compared the survivors versus non-survivors using Chi-square test for categorical variables and Student's T-test for continuous variables. We did logistic regression analysis on those variables with statistically significant difference (p-value less than 0.05), followed by multivariable analysis. Results Out of 156 patients that had axillary IABP as BTT- 6 patients (3.8%) died while on IABP support whereas 136 (86.5%) patients were successfully bridged to transplant. The remaining 15 patients required escalation of therapy in the form of Impella (5 patients), left ventricular assist device (7 patients) and total artificial heart (3 patients). Patients that died on IABP support had higher right atrial pressure (RAP) and lower left ventricular end diastolic internal diameter (LViDd) compared to patients that survived. The results are shown in Table 1 and Table 2 . Conclusion Our study shows that patients that survived on axillary IABP support had significantly different RAP and LViDd compared to the patients that died. Interestingly, we also found that cardiac power was not predictive of clinical success in these patients.