Results:
Between November 2010 and September 2017, 47 cardiac arrest patients were initiated on ECMO at the time of active CPR for cardiac arrest. Baseline characteristics for survivors and non-survivors are described in Table 1. ECPR patients were more commonly male (n=33; 70.2%) with a median age of 53 years. The majority of patients had underlying cardiovascular disease, including 20 patients (42.6%) with known cardiomyopathy and 27 (57.4%) with coronary artery disease.
Arrest and cannulation locations are described in Table 2. Forty-five patients (95.7%) experienced an in-hospital cardiac arrest while two patients experienced an out-of-hospital arrest but were cannulated in the hospital while receiving CPR (4.3%). The most common locations for both arrest and cannulation were the cardiac catherization lab and the intensive care unit.
Arrest rhythms were either PEA (n=25; 53.2%) or pulseless VT/VF (n=22; 46.8%). Arrest etiologies included acute coronary syndromes (n=17; 36.2%), acute heart failure syndromes (n=10; 21.3%), pulmonary embolism (n=7; 14.9%), primary arrhythmia (n=5; 10.6%), drug toxicity or overdose (n=2; 4.3%), and other causes (n=6; 13%), including tamponade (n=2), air embolism (n=1), perioperative hemorrhagic shock (n=1), and sepsis/endocarditis (n=2) . In total, 4 patients (8.5%) experienced arrest post-cardiotomy (from tamponade, PE, VT storm, and VF), with 50% of these patients dying while on ECMO and the remaining surviving to discharge.
Overall, 34 patients (72.3%) were adjudicated to have a primary cardiac origin of their cardiac arrest. There was no significant association found between etiology of arrest, arrest rhythm, or cardiac versus non-cardiac origin of arrest and survival to discharge. Similarly, no combination of arrest origin (cardiac or non-cardiac) and arrest rhythm (PEA or VT/VF) was significantly associated with survival to discharge [Table 3].
ECMO characteristics are described in Table 4. Almost all patients underwent peripheral cannulation. Following cannulation, 22 (46.8%) were underwent targeted temperature management, 19 (40.4%) had a subsequent revascularization procedure, and 6 (12.8%) had a venting ventricular assist device placed. Median time on ECMO support was 3.00 days.
ECMO-related complications included major bleeding (n=28; 59.6%), renal replacement therapy (n=24; 51.1%), cerebrovascular accident (n=10; 21.3%), and limb ischemia (n=8; 17.0%) [Table 5].
Overall ECPR patient survival to hospital discharge was 25.5% (n=12). Twenty-six patients died on ECMO (55.3%) while 9 patients (19.1%) survived ECMO decannulation but died prior to discharge. The majority of patients who survived to discharge experienced myocardial recovery (n=10; 83%); one patient underwent orthotopic heart transplantation (8.3%), one received a durable ventricular assist device (8.3%), and 2 required new dialysis at discharge (16.7%). Most survivors had a favorable CPC score of 1 at discharge (n=9; 66.7%) [Table 6]. Median intensive care unit and hospital length of stay for survivors was 28.5 [IQR 13.50, 39.50] and 35.50 days [IQR 21.75, 49.50] respectively. Causes of death in non-survivors are listed in Table 7.
In univariate analysis, characteristics associated with survival to discharge include younger age (median 44.0 [IQR 45.00,64.00] in survivors versus 60.00 in non-survivors [IQR 46.00, 6.65]; p 0.034) and arrest location in the emergency department (33.3% of survivors versus 2.9% of non-survivors; p=0.012). Arrest etiology of pulmonary embolism approached but did not cross the pre-established threshold for significance (33.3% of survivors versus 8.6% of non-survivors, p=0.060).