Long-term outcomes among out-of-hospital cardiac arrest survivors with reversible versus non-reversible causes
Carlo Alberto Barcella, Brian E Grunau, Meijiao Guan, Nathaniel M Hawkins, Marc W Deyell, Jason G Andrade, Jennie S Helmer, Graham C Wong, Kristian H Kragholm, Karin H Humphries, Jim Christenson, Christopher B FordyceAbstract
Background
Reversible cause of out-of-hospital cardiac arrest (OHCA) is vaguely defined in international guidelines as an identifiable transient or potentially correctable condition. Moreover, studies evaluating long-term outcomes of patients experiencing OHCA due to reversible and non-reversible causes are lacking. We aimed to determine differences in long-term outcomes in OHCA-survivors according to different etiology.
Methods
From the British Columbia Cardiac Arrest registry, adults with non-traumatic OHCA (2009-2016) surviving to hospital discharge were identified. Patients were categorized by OHCA etiology combining reversibility and underlying ischemic etiology. The primary outcome was a composite of all-cause mortality, recurrent OHCA, or re-hospitalization for sudden cardiac arrest or ventricular arrhythmias. Using the Kaplan-Meier method and multivariable Cox regression models, we compared the risk of the composite outcome according to different OHCA-etiology.
Results
Of 1,325 OHCA hospital-discharge survivors (median age 62.8, 77.9% male), 431 (32.5%) had reversible ischemic, 415 (31.3%) non-reversible ischemic, 99 (7.5%) reversible non-ischemic and 380 (28.7%) non-reversible non-ischemic etiology. At 3 years post-discharge, Kaplan-Meier event-free rate was highest in patients with a reversible ischemic etiology (91%, 95% CI 87-94%), and lowest in those with a reversible non-ischemic etiology (62%, 95% CI 51-72%). In multivariate analyses, compared to non-reversible non-ischemic cause, reversible ischemic cause was associated with a significantly lower hazard ratio (HR) (0.52, 95% confidence interval [CI], 0.33-0.81), reversible non-ischemic cause with a significantly higher HR (1.53, 95% CI, 1.03-2.32) and non-reversible ischemic cause with a non-significant HR 0.92 (95% CI, 0.64-1.33) for the composite outcome.
Conclusions
The presence of a reversible ischemic cause is associated with long-term OHCA-outcomes.