(1694) VA ECMO in Refractory Shock With Preserved Left Ventricular due to Acute CCB Ingestion

Introduction: Venoarterial extracorporeal membrane oxygenation (VA ECMO) has been included in international guidelines for the treatment of refractory cardiogenic shock. Previous studies of patients with septic shock examining the role of VA ECMO in states of severe shock with preserved left ventricular (LV) function have failed to show benefit. Available literature is limited to few case studies suggesting there may be benefit in the use of VA ECMO in refractory shock and preserved LV function due to acute calcium channel blocker (CCB) ingestion.

Description: This case series describes two patients who presented with refractory vasodilatory shock in the setting of CCB overdose. Both patients received standard therapy for CCB overdose including vasopressors, high dose insulin, and replacement of calcium. They also received salvage therapy for refractory hypotension with methylene blue. Despite treatment both continued to have profound shock, evidence of end organ dysfunction, and concern for death without further intervention. On bedside echocardiography both patients demonstrated preserved LV function. They were percutaneously cannulated at bedside for VA ECMO in the setting of refractory shock. Following initiation of VA ECMO both patients had significant reduction in vasopressor requirements. Formal echocardiography was performed confirming preserved LV function. After improvement in shock state both patients had successful bedside decannulation.

Discussion: VA ECMO may improve outcomes in the setting of refractory shock with preserved left ventricular function due to acute CCB toxicity. This differs from the previous literature base evaluating the role of VA ECMO for refractory shock with preserved LV function in the setting of sepsis. The mechanism by which VA ECMO may provide benefit could be explained by improved regional perfusion to the brain, coronary vasculature, and intra abdominal vasculature, thereby reducing the risk of hypoxic brain injury, worsening cardiovascular function, or bowel ischemia. VA ECMO has many risks, however, when faced with refractory shock due to acute toxic ingestion of CCB, VA ECMO may be beneficial when pharmacologic interventions have been unsuccessful.