«Iabp or not iabp?» – that is the question. Predicting the optimal method of mechanical circulatory support in patients with postcardiotomy shock

Aim. To determine the criteria for selecting the optimal method of mechanical circulatory support (MCS): intra-aortic balloon pump (IABP) or extracorporeal membrane oxygenation (ECMO), needed for patients with post-cardiotomy shock. Methods. A retrospective study was conducted at the Republican Scientific and Practical Center “Cardiology” for the period 2012–2020. Inclusion criteria for the study were patients aged 18-80 years who underwent heart surgery under cardiopulmonary bypass (CPB), and who have intraoperatively developed postcardiotomy shock refractory to drug therapy. As it was impossible to disconnect the patient from CPB, the use of mechanical circulatory support (MCS) was required. The patients selected were those who underwent ECMO (n = 28) and were successfully discharged from the hospital. Using the pseudorandomization method based on “the nearest neighbour” algorithm (kNN – Nearest Neighbours), in a 1:1 ratio the surviving patients with IABP (n = 28) were selected. Thus, 56 patients were included in the study. Based on the analysis of logistic regression, the criteria for choosing the optimal MCS method were determined. The intensity of inotropic and vasopressor therapy was determined in points (Vasoactive Inotrope Score), based on the following formula: VIS (points) = dobutamine (mcg/kg/min) + dopamine (mcg/kg/min) + 100 × norepinephrine (mcg/kg/ min) + 100 × epinephrine (mcg/kg/min) + 10 × milrinone (mcg/kg/min) + + 10,000 × vasopressin (units/kg/min) + 50 × levosimendan (mcg/kg/min) 1. Results. The criteria determining the need for ECMO were defined: clinical presentation of pulmonary edema OR = 23,4 95% CI 4,52 – 119,7, p = 0.001; arterial blood lactate > 4 mmol/L (Sn = 68%, Sp = 68%), OR = 7,7 95% CI 2,32 – 25,74, p = 0.001; pH –4,3 (Sn = 75%, Sp = 70,4%), OR = = 7,15 95% CI 2,16 – 23,42, р = 0,001; vasoactive and inotropic support more than 35 points (Sn = 57,1%, Sp = 75%), OR = 4,45 95% CI 1,45 – 13,68, p = 0,015. A prognostic model was developed to determine the optimal MCS based on arterial blood saturation, blood lactate values, the duration of CPB, and the values of vasoactive and inotropic support. Conclusion. Postcardiotomy shock is a severe complication in cardiac surgery characterized by high in-hospital mortality due to the development of multiple organ failure syndrome. The use of inotropic and vasopressor drugs leads to temporary hemodynamic improvement. Increasing vasoactive support causes lactate acidosis, which entails a weakening of the catecholamines effectiveness and leads to greater escalation of pharmacological support. Timely connection of the necessary MCS option based on the developed model will make it possible to efficiently use the resources of cardiac surgery centers, reduce the incidence of multiple organ failure and in-hospital mortality.