Left ventricular distention under venoarterial extracorporeal membrane oxygenation support: when should we consider percutaneous left heart decompression?

Abstract

In the June 2017 issue of the ASAIO Journal, Truby et al. described a retrospective, monocenter cohort of 121 patients who underwent veno-arterial extracorporeal membrane oxygenation (VA-ECMO) implantation because of refractory cardiogenic shock (1). Authors stratified patients in three distinct groups according to a new proposed definition of left ventricular distention (LVD) severity based on clinical, hemodynamic and radiologic criteria: (I) clinical LVD (LVD++) if "mechanical intervention to decompress the LV was initiated immediately after VA-ECMO because of pulmonary edema, ventricular arrhythmia, or significant stagnation of blood within the LV"; (II) subclinical LVD (LVD+) if "evidence of pulmonary edema on chest radiograph and pulmonary artery diastolic pressure greater than 25 mmHg within the first 2 hours of VA-ECMO support"; and (III) no LVD (LVD−) in the absence of the above criteria.Significant baseline differences existed between groups: 33% of LVD++ patients had post myocardial infarction refractory cardiogenic shock while 55% of LVD+ had postcardiotomy shock. More importantly, cardiopulmonary resuscitation was performed in 67% of LVD++ compared to 11% and 19% of LVD+ and LVD−, respectively. Furthermore, all LVD++ patients had an LV ejection fraction lower than 30% compared to 50% in the LVD+ group and 40% in the LVD−. After a mean duration of VA-ECMO support of 4.11±2.98 days, the overall survival to discharge was 43% and did not differ between groups. However, only 20% of LVD++ survivors achieved myocardial recovery defined as absence of longterm mechanical support. In comparison, 60% of LVD+ and 20% of LVD− achieved myocardial recovery. One major finding was that survival to discharge was 44.4% (4/9) in those patients who benefited from early decompression, all of which were in the LVD++, versus only 10% (1/10) in those of the LVD+ group who underwent a late decompression. The only preoperative factor that was significantly predictive of the need of decompression in the multivariate model was extracorporeal cardiopulmonary resuscitation (odds ratio: 3.64, confidence interval: 1.21-10.98; P=0.022).Although the results are interesting, authors advocate significant limitations that may have impacted the interpretation of study findings. Only 105 out of 226 VA-ECMO runs were included in the analysis, the other ones being excluded because of insufficient hemodynamic data.

Hurdles to Cardioprotection in the Critically Ill

“…This can lead to LV distension as the impaired LV is unable to generate sufficient power to overcome the increased afterload in order to eject blood. This causes progressive LV dysfunction, wall stress, pulmonary edema, and impairment of myocardial oxygenation [71,72]. In order to address these complications, a number of strategies to facilitate LV unloading are suggested.…”