Cardiogenic shock treated with temporary mechanical circulatory support in Brazil: The effect of learning curve.

Aims: Treatment with mechanical circulatory support (MCS) has been proposed to mitigate mortality in cardiogenic shock (CS). However, there is a lack of data on MCS programs implementation and the effect of the learning curve on its outcomes in limited resources countries such as Brazil.
Methods: Prospective cohort of patients with CS admitted in four tertiary-care centers treated with Impella CP or veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Clinical outcomes were peri-procedural complications, short-term mortality rate, and the centers' learning curve. The cohort was divided into two periods: from April 2017 to July 2018 ( n  = 24), and from August 2018 to December 2020 ( n  = 25).
Results: The study enrolled 49 patients [age 59 (43-63) years; 34 (70%) males]. The most common causes for CS were acute myocardial infarction in 22 (45%) and acute decompensation of chronic heart failure in 10 (20%). VA-ECMO was employed in 35 (71%) and Impella CP in 14 (29%) of patients. Overall complications occurred in 37 (76%) of patients, where major bleeding in 19 (38%) was the most common. The overall mortality rate was 61%, but it was lower in the second period (40%) in comparison to the first period (83%), p  = 0.002. The learning curve analysis showed a decrease in the mortality rate after 40 consecutive cases.
Conclusions: Implementation of a temporary MCS program for refractory CS in a limited resource country is feasible. The learning curve effect might have played a role on survival rate since high morbimortality has decreased within time reaching optimal results by the end of the study.