Long-term major events after hospital discharge for out-of-hospital cardiac arrest

Abstract

Background: Cardiac arrest remains a global health issue with limited data on long-term outcomes, particularly regarding recurrent cardiovascular events in patients surviving out-of-hospital cardiac arrest. (OHCA). We aimed to describe the long-term occurrence of major cardiac event defined by hospital admission for cardiovascular events or death in OHCA hospital survivors, whichever came first. Our secondary objective were to assess separately occurrence of hospital admission and death, and to identify the factors associated with major event occurrence. We hypothesized that patients surviving an OHCA has a protracted increased risk of cardiovascular events, due to both presence of the baseline conditions that lead to OHCA, and to the cardiovascular consequences of OHCA induced acute ischemia-reperfusion.

Methods: Consecutive OHCA patients from three hospitals of Sudden Death Expertise Center (SDEC) Registry, discharged alive from 2011 to 2015 were included. Long-term follow-up data were obtained using national inter-regime health insurance information system (SNIIRAM) database and the national French death registry. The primary endpoint was occurrence of a major event defined by hospital admission for cardiovascular events and death, whichever came first during the follow-up. The starting point of the time-to-event analysis was the date of hospital discharge. The follow-up was censored on the date of the first event. For patients without event, follow-up was censored on the date of December, 29th, 2016.

Results: A total of 306 patients (mean age 57; 77% male) were analyzed and followed over a median follow-up of 3 years for hospital admission for cardiovascular event and 6 years for survival. During this period, 38% patients presented a major event. Hospital admission for cardiovascular events mostly occurred during the first year after the OHCA whereas death occurred more linearly during the all period. A previous history of chronic heart failure and coronary artery disease were independently associated with the occurrence of major event (HR 1.75, 95%CI[1.06-2.88] and HR 1.70, 95%CI[1.11-2.61], respectively), whereas post-resuscitation myocardial dysfunction, cardiogenic shock and cardiologic cause of cardiac arrest did not.

Conclusion: Survivors from OHCA must to be considered at high risk of cardiovascular event occurrence whatever the etiology, mainly during the first year following the cardiac arrest and should require closed monitoring.

Keywords: Cardiac arrest; Cardiovascular outcome; Death; Long-term outcomes; Out-of-hospital cardiac arrest.

Fig. 1

Flow-Chart. Detail patients including in the analysis and reason for exclusion. OHCA : Out-of-Hospital Cardiac Arrest; SDEC: Sudden Death Expertise Center; ROSC: Return Of Spontaneous Circulation; E-CPR : Extra-corporeal-Membrane-Oxygenation associated to Cardio-Pulmonary-Resuscitation; ICU: Intensive Care Unit Of note, among 306 patients included in analysis, CeDC data were not available for 33 patients

Fig. 2

Occurrence of major event, Kaplan-Meier representation. A. Shown is Kaplan-Meier estimates of patients free from major events over time. B. Shown is Kaplan-Meier estimates of long-term outcome (i.e., composite factor including hospital admission for cardiovascular events or deaths) occurring during the follow-up period, expressed in event per patient-year. The starting point of the time-to-event analysis was the date of hospital discharge of survivors after OHCA

Fig. 3

Secondary endpoint, Kaplan-Meier representation. A. Shown is Kaplan-Meier estimates of hospital admission for cardiovascular events occurring during the follow-up period, expressed in event per patient-year. B. Shown is Kaplan-Meier estimates of deaths from any cause occurring during the follow-up period, expressed in event per patient-year. For both, the starting point of the time-to-event analysis was the date of hospital discharge of survivors after OHCA