Reply: Right, wrong, or somewhere in between?

Reply to the Editor:

R.C.A. has an unrestricted grant from Pfizer Canada Inc and has received honoraria from Abbott Nutrition, Edwards Lifesciences, and AVIR Pharmaceuticals for work unrelated to this manuscript. All other authors reported no conflicts of interest.

The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.

Grunfeld and colleagues provide interesting insight on a potential mechanism for observed increases in right-sided stroke that were recently reported during right axillary venoarterial extracorporeal membrane oxygenation (ECMO). In addition to embolization, they suggest that mixing between ECMO flow and the native cardiac output may produce an environment predisposing to right-sided stroke, including through blood stasis and leading to innominate artery thrombosis, supported by compelling clinical images.

Differential oxygenation (ie, “North-South” or “Harlequin” syndrome) is a well-known potential downside of peripheral venoarterial ECMO, wherein the native cardiac output competes with retrograde ECMO flow and differentially perfuses the right brachiocephalic and carotid arteries with deoxygenated blood. Although we have not experienced this complication as vividly as described by Grunfeld and colleagues, the analogous mechanism is certainly a plausible explanation for the observed findings after axillary cannulation and one for which all peripherally cannulated patients must be closely monitored.

Notably, this complication may be obviated by using central cannulation. One approach that we have taken in carefully selected patients is that of closed-chest central ECMO cannulation. In this approach, a standard aortic arch cannula is tunneled through the right second intercostal space into the ascending aorta while a 2-stage venous cannula is tunneled through the abdominal fascia and into the right atrium with the tip positioned in the inferior vena cava. If desired, an apical left ventricular vent can be inserted with the assistance of a long angiocatheter and modified Seldinger technique for dilation of the apex and a left inframammary incision. Standard sternotomy closure may then be performed. This provides the early chest closure benefits of peripheral cannulation, including careful patient mobilization, although hemostasis must be particularly meticulous, given the need for systemic heparinization.