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

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.

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).

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.

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.