Outcome of right ventricular microaxial pump support in patients undergoing cardiac surgery | Scientific Reports – Nature.com

This study is the largest single center retrospective cohort in Europe with Impella-RP for patients with RVF after cardiac surgery. We evaluated which factors provided an approximation of right ventricular function in the postoperative period. Due to the lack of a consensus definition of RVF, and the fact that RVF mechanisms have not been well defined9, we evaluated liver function and assessed catecholamine variability as a noninvasive hemodynamic prediction metric. As these factors could be influenced by external complications and were, by nature, secondary assessors for determining right heart function, we performed invasive hemodynamic prediction measurements of CI and mean pulmonary artery pressure (mPAP). We found that patients undergoing isolated myocardial revascularization surgery had significantly higher survival after Impella-RP treatment than patients who had undergone valve or combined surgery, and that Impella-RP therapy significantly improved CI in most patients. We did not find any significant association with mortality for any of the metrics evaluated, though total bilirubin on the last day of Impella-RP treatment and ALT on the first and third days of Impella-RP treatment trended towards significance.

A significant correlation with mortality after 30 days was observed among patients with elevated pulmonary capillary wedge pressure (PCWP) prior to Impella-RP support. It is relevant to note that elevated PCWP levels may indicate severe left ventricular failure or severe mitral stenosis. Among our patients, it is noteworthy that those included in the study had preserved left ventricular function. However, the observation of elevated PCWP levels, which serves as a reasonable surrogate marker of left atrial pressure and left ventricular end-diastolic pressure, suggests that despite compensatory cardiac function, elevated pressures were detected. This indicates a preceding hemodynamic disturbance that could influence the evaluation of these patients, potentially masking global ventricular dysfunction10,11.

The use of Impella-RP was most beneficial for patients undergoing isolated myocardial revascularization surgery who develop RVF after open-heart surgery. This might indicate that bridging of ischemia caused RVF to recovery is more likely than non-ischemic RVF. Importantly, despite hemodynamic instability at the time of Impella-RP implantation, these patients developed complete right heart recovery and hemodynamic stability with no mortalities, which was maintained after explantation of the Impella-RP. Impella-RP treatment also resulted in an increased cardiac index in almost all patients, though likely due to the breadth of pathology of these patients, it was not significantly related to survival; regardless, it improved systemic perfusion, enhanced end-organ perfusion, and enabled prompt withdrawal of inotropic and vasopressor support. RVF as a complication after cardiac surgery is challenging to treat and is associated with increased short-term mortality1,12,13 and extended hospitalizations; this unsurprisingly results in commensurate cost increases. Thus, implementation of Impella-RP is not only beneficial to improving RV recovery and cardiac output, but it also reduces costs associated with complications from open heart surgery and extended hospitalization times.

The overall mortality evinced by this study is notably lower than that seen in the literature, where overall mortality has reportedly been as high as 51%2. In this analysis, overall mortality was closer to that of the RECOVER RIGHT and subsequent conformity assessment and post approval studies (26.7%)1,5. It may be that patient selection was important for this, as the cohort in this study contained exclusively patients who underwent cardiac surgery with cardiopulmonary bypass and required therapeutic management of RVF with an Impella-RP. In studies that include consecutive Impella-RP placements, patients could be experiencing RV failure due to numerous conditions, including post-LVAD implantation, acute pulmonary embolism, post-cardiotomy RV failure, post-myocardial infarction shock, and nonischemic cardiomyopathy2; it may be that the varied etiologies for RVF result in different therapeutic approaches in addition to MCS. Furthermore, the timing of Impella-RP usage may be crucial to improving mortality outcomes for this population, as this is the case for left ventricular failure MCS14,15, and recent work has suggested this holds true for RVF as well16,17. Future analyses will need to focus on these factors to ensure the patients who are best served by Impella-RP usage are treated when appropriate for the best odds of survival and recovery.

The principal hemodynamic benefit of Impella-RP is a direct increase in pulmonary artery flow and a concomitant unloading of the RV6,18. As described in the RECOVER RIGHT study in 20155, the use of Impella-RP is safe and effective in improving hemodynamics in patients with severe RVF refractory to medical therapy. Given that Impella-RP is a percutaneous right ventricular assist device support, it not only facilitates fast implantation, but also effectively reduces the right ventricular workload without the need for cardiotomy, achieving prompt hemodynamic stabilization of the patient before shock becomes irreversible. Complications such as bleeding or AvWS were managed by clinicians and did not demonstrate increased mortality. Due to the wide range of pathologies of our patients, it is difficult to clarify the specific pathophysiology that results in acute RVF. Factors such as elevated liver function parameters may indicate an advanced stage of RVF at the time of implantation and as such may not be sufficient for treatment with Impella-RP.

Overall, Impella-RP is safe and effective and can be used as standard treatment for a select group of patients. Although our data shows an improvement of hemodynamics in almost all patients, the survival of the patients depends on many other factors. The influence of other factors to mortality has to be addressed in a future prospective study.

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Outcome of right ventricular microaxial pump support in patients undergoing cardiac surgery | Scientific Reports - Nature.com