MATERIALS AND METHODS
Outcomes for patients receiving an HVAD via LTHS from 2013-2019 were compared among those bridged with ECMO, IABP, or no tMCS. We evaluated demographics, comorbidities, laboratory, echocardiographic, and hemodynamic data, and intra- and postoperative outcomes. These data were collected prospectively in an IRB-approved MCS program database.
Use of LTHS with the HVAD, as described by Schmitto3, became our standard technique in April 2016. Prior to this, two patients underwent LTHS HVAD insertion. At the same time, we made VA ECMO our primary method of supporting patients in severe cardiogenic shock. In the preceding period, tMCS modality was dependent on surgeon preference, and could include ECMO or a percutaneous or surgical VAD.
IABP therapy was used for patients declining on inotropes, or who were inotrope-intolerant but not in severe shock (INTERMACS 2). Standard approach until 2019 was femoral insertion, which precludes ambulation. The goal was normalization of end-organ function and optimization of hemodynamics prior to dLVAD. Patients who continued to decline on IABP were converted to ECMO.
ECMO was initiated via peripheral cannulation. Distal perfusion cannulas were inserted routinely. The preferred strategy to relieve pulmonary edema was inotropes, followed by atrial septostomy5,6if necessary. Patients were managed in the cardiac surgery intensive care unit by a dedicated ECMO team. Patients were extubated and allowed to participate in physical therapy7, including ambulation8. They were maintained on ECMO until resolution of end-organ dysfunction and vascular congestion, although dLVAD could be expedited in the face of ECMO complications.
Preoperative data were collected as near as possible to dLVAD implant. Exceptions were echocardiographic and hemodynamic data for ECMO patients, which were collected prior to ECMO. Pre-tMCS laboratory data were also collected. INTERMACS profile was determined by our multidisciplinary MCS team. Based on the analyses of Shah9,10, it is our practice to assign all ECMO patients to INTERMACS 1, regardless of post-ECMO improvement. In patients supported with more >1 modality of tMCS, the final one prior to dLVAD was used for group assignment. Duration of tMCS was based on the final run prior to dLVAD. Patients were assigned to the tMCS groups if they had undergone support with either modality within a week of dLVAD. Complications were defined per INTERMACS criteria and included major and GI bleeding, device-related infection, and stroke (CVA). These were evaluated during the early (<3 month) and late (>3 month) postoperative periods. Patients were followed through death, transplant/explant, or February 29, 2020.
Statistical analysis was performed with Statistica 13 (Dell, Inc; Tulsa, OK). Normality was assessed with the Shapiro-Wilks and Kolmogorov-Smirnov tests. Normally distributed data are reported as mean±standard deviation, and non-normal data as median (interquartile range) (IQR). Continuous variables were compared between the three groups using one-way ANOVA for normally-distributed data, and the Kruskal-Wallis test for non-normal data. Comparison of pre- and post-tMCS variables between IABP and ECMO were made with a paired t-test or Mann-Whitney U test. Categorical variables were compared with the Pearson chi-squared test. Incidence rates for complications were compared using Poisson regression. Kaplan-Meier curves were used to depict survival by group, and were compared with the log-rank test. Ap -value <0.05 was considered significant.