Dr Hernandez-Montfort began by stating that acute heart failure (AHF) with cardiogenic shock (CS) remains a complex, heterogenous and time-sensitive disease entity that continues to challenge healthcare systems across the globe.1,2 He drew attention to the fact that escalating doses of inotropes in AHF with CS are associated with exponential mortality.3 He noted that contemporary care in AHF complicated with CS includes the use of temporary circulatory support (TCS) as a therapeutic bridge strategy that can potentially aid the transition to replacement therapies, such as durable ventricular assist devices (dVAD).2
There are limited data characterising longitudinal transitions for patients with AHF and CS receiving TCS prior to dVAD, despite its increased utilisation.4,5 Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) patient profiles 1–3 are commonly utilised, although they also have shown to be heterogeneous descriptors of severity of illness prior to dVAD.6 Hence, it is unclear whether a preimplant TCS strategy affects short- and long-term survival after dVAD. Also, specific TCS device/phenotype associated with recovery, replacement or palliation are yet to be characterised.
The aim of Dr Hernandez-Montfort’s study was to describe the global epidemiology of patients receiving TCS (defined as preoperative use of extracorporeal membrane oxygenation [ECMO], intra-aortic balloon pump [IABP] and other TCS, including Centrimag, Impella and Tandem Heart) before durable left ventricular assist device (LVAD) implantation. In addition, to examine the short- and long-term survival of patients receiving TCS patients versus those not receiving TCS.
A total of 16,754 adult patients were implanted with dVAD in the International Society for Heart and Lung Transplantation Registry for Mechanically Assisted Circulatory Support (January 2013–November 2017). Of these, 13,813 patients had INTERMACS patient profile 1–3 and received a continuous flow LVAD (CF-LVAD) or biventricular assist device (BiVAD). A total of 5,632 patients received preoperative TCS before receiving CF-LVADs or BiVADs, while 7,879 belonged to the non-TCS group. The TCS support was classified as ECMO (1,138), IABP (3,901) and other TCS (593).
ECMO was used as TCS prior to dVAD mainly in Europe (17%), followed by Asia-Pacific (9%) and the Americas (8%). IABP was used mostly in the Americas (31%), followed by Asia-Pacific (26%) and Europe (11%). Other TCS was used mostly in Asia-Pacific (13%), with similar utilisation in the Americas and Europe (4% each). The majority of patients receiving ECMO (77.6%) had INTERMACS profile 1. However, only 20.5% were bridged to transplant. All patients who received TCS had signs of right and left heart loading conditions and myocardial impairment, whereas patients on ECMO had elevated bilirubin levels, indicating liver congestion. Also, patients on ECMO were likely to receive BiVAD (22.1%), centrifugal pump (49.1%) and concomitant surgery (77.1%). The length of intensive care unit (ICU) stay (24 days) and implant-to-discharge duration (40 days) was longer with ECMO than IABP or other TCS support.
Importantly, patients receiving TCS support had lower survival than those not receiving TCS support at 2 years. Also, patients on ECMO had lower survival compared to patients treated with IABP or other TCS support. Multivariable analysis identified ECMO (versus other TCS) to be associated with increased risk of early death (HR 2.03, p<0.0001). Also, surrogates of kidney and liver function (such as creatinine and bilirubin) and right heart load (central venous pressure) were associated with early death. Similar results were obtained in the propensity-matched cohort of ECMO versus other TCS, ECMO versus IABP and ECMO versus non-TCS.
In summary, there are regional differences in pre-implant TCS, with ECMO being more commonly used in Europe than other regions. Patients requiring pre-implant TCS had lower longitudinal survival compared to patients without TCS.
Patients with pre-implant ECMO were less likely to receive dVAD as bridge to transplant and more likely to receive BiVAD. Patients on pre-implant ECMO had the highest median ICU length of stay and the lowest median time on dVAD. Further research in patients with INTERMACS profile 1–3 transitioning to dVAD is needed to better understand the differences in survival with ECMO versus other TCS.