Commentary: Getting in the groove with salvage extracorporeal membrane oxygenation and left ventricular venting

Douglas M. Overbey, MD, MPH, and Andrew J. Lodge, MD

Central Message.

An extracorporeal membrane oxygenation (ECMO) cannulation and flow maintenance-strategy are proposed to support recovery after posterior atrioventricular groove disruption during mitral valve repair.

See Article page 213.

Salna and colleagues¹ present 2 cases of a relatively unique extracorporeal membrane oxygenation (ECMO) cannulation and flow strategy to facilitate recovery following a catastrophic complication of mitral valve repair. In each case, mitral valve repair was complicated by posterior atrioventricular (AV) groove disruption, then managed with internal patching and valve replacement. Cannulation was then reconfigured using both right atrial drainage and a left ventricle (LV) apical vent to prevent distention. This strategy was used for 3 to 4 days postoperatively to decompress the LV to facilitate hemostasis at the repaired AV groove and allow myocardial rest and recovery following a long clamp time. Flow and drainage were titrated using a partial occlusion clamp on the right atrial inflow to ensure 5- to 10-mm Hg pulsatility in the pulmonary artery and >1.5 L flow through the apex cannula. The goals, in addition to ensuring decompression of the LV for enhanced hemostasis and recovery, were also to ensure adequate flow through the mitral valve to prevent thrombosis of the prosthetic valve and adequate flow through the apical cannula to prevent thrombosis in the absence of immediate postoperative heparin administration. Both patients recovered successfully, highlighting the potential success of creative new salvage therapies involving ECMO for otherwise-devastating complications.

The strength of this report is the salvage of 2 patients from a complication carrying a very high mortality. The authors have capitalized on the expansion of adult ECMO that has involved improved safety and greater levels of comfort taking care of such patients. This novel venting and flow strategy used may allow enhanced hemostasis at the repair site through a decompressed LV without compromising the newly situated mitral valve. This strategy is well explained and should be transferrable to other surgeons and perhaps other complications like ventricular rupture. Although left ventricular decompression is not infrequently needed with conventional veno-arterial ECMO support of cardiac patients due to the increased afterload,^2,3 this report describes a novel use under dire circumstances. Although postcardiotomy ECMO is associated with high complication rates and low survival, it is often undertaken as salvage when no other options are available.⁴ Limitations of this report include its small size, thus representing proof of concept rather than an analysis of results. The potential impact for this adjunct is that it adds an option where few exist and stimulates further surgical innovation for salvage ECMO techniques.

An important consideration with the salvage strategy described is potential for air entrainment into the circuit. The strategy was only used after ongoing bleeding following repair, raising concern over the integrity of the repair. This creates a potential for air entrainment into the circuit through the repair site into the LV vent cannula, particularly in the setting of an open chest. Avoidance of this complication includes meticulous management of flows through each cannula to decompress the ventricle while preventing suction events. This management would include very close continuous observation of the ECMO circuit and dynamic changes of volume status and heart function. Also, and importantly, the authors point out that their approach is an adjunct to conventional surgical therapy and should not be used as a primary treatment for AV groove rupture. The proposed strategy should be reserved for refractory cases of atrioventricular groove rupture but offers an important bailout strategy where other options are sparse.