Abstract
Peripheral veno-arterial extracorporeal membrane oxygenation (pVA-ECMO) has gained increasing value in the management of advanced cardiogenic shock. Unloading the left ventricle (LV) while reducing myocardial oxygen consumption (MVO2) are crucial for myocardial recovery during pVA-ECMO. To study the effects of a pulmonary capillary wedge pressure (PCWP)-directed protocol in patients on pVA-ECMO (goal: PCWP <18 mmHg), we performed a retrospective analysis of our ECMO database. In particular, we sought to identify risk factors for lack of myocardial recovery, i.e. need for durable mechanical circulatory support (dMCS) after pVA-ECMO.
Following IRB approval, we identified 99 patients with advanced cardiogenic shock undergoing pVA-ECMO and at least one formal transthoracic echocardiography study (TTE) during pVA-ECMO. We analyzed demographic data, routine laboratory data, hemodynamic parameters, and TTE results. We used PCWP measurements and calculations of LV systolic wall tension (LVSWT) to assess LV unloading and MVO2 during pVA-ECMO, respectively. Statistical analyses included Mann-Whitney-U test and logistic regression modeling. Data are given as median (interquartile range).
Survival to hospital discharge was 60.6%. 27.3% of all patients required transition to dMCS to be weaned off pVA-ECMO. 10.1% of all patients developed refractory LV distention with pulmonary edema despite maximum medical treatment and required either atrial septostomy or additional mechanical support. Minimum PCWP readings during pVA-ECMO were 12.8 mmHg (11.0-14.4) in patients without and 10.0 mmHg (8.0-17.0) in patients with need for dMCS (p=0.236). Minimum LVSWT during pVA-ECMO were 2.7 × 105 dynes/cm (2.0-3.5) in patients without and 3.5 × 105 dynes/cm (3.1-4.0) in patients with need for dMCS (p=0.002). Adjusting for age and race in a logistic regression model revealed that only post-cardiotomy pVA-ECMO and LVSWT, but not minimum PCWP were independently associated with need for dMCS after pVA-ECMO.
We show that strict medical management can lead to LV unloading, i.e. minimum PCWP < 18 mmHg, in the vast majority of patients requiring pVA-ECMO for advanced cardiogenic shock. However, high LVSWT during pVA-ECMO remained predictive of need for dMCS even with unloaded LV.
