How small is enough for the left heart decompression cannula during extracorporeal membrane oxygenation?

Background: Left ventricular (LV) distension is a recognizable problem accompanied by subsequent complications during venoarterial extracorporeal membrane oxygenation (VA-ECMO). However, no gold standard for LV decompression has been established, and no minimal flow requirement has been designated. Thus, we evaluated the efficacy of the 8-Fr Mullins sheath for left heart decompression during VA-ECMO in adult patients. Methods: Left heart decompression was performed when severe pulmonary edema was detected on chest radiography or when no generation of pulse pressure followed severe LV dysfunction in patients receiving VA-ECMO. We punctured the interatrial septum and inserted an 8-Fr Mullins sheath into the left atrium via the femoral vein. The sheath was connected to the venous catheter used for ECMO. The catheter was maintained during VA-ECMO. Results: The left heart decompression procedure was performed in seven of 35 patients who received VA-ECMO between February 2017 and June 2018. Three patients had acute myocardial infarction; three, fulminant myocarditis; and one, dilated cardiomyopathy. Four patients showed noticeable improvement of pulmonary edema within 3 days, and three patients with a pulse pressure of <10 mm Hg showed an increase in pulse pressure of >20 mm Hg within 24 hours from the left heart decompression procedure. All seven patients were successfully weaned from VA-ECMO. No complications related to the left heart decompression procedure occurred. Conclusions: An 8-Fr sheath may be a possible option for left heart decompression in adult patients with LV distension under VA-ECMO who are expecting recovery of LV function.