Five-Year Outcome after Coronary Artery Bypass Surgery in Survivors of Out-of-Hospital Cardiac Arrest

Long-term Survival After Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-analysis

Importance

Data on long-term survival beyond 12 months after out-of-hospital cardiac arrest (OHCA) of a presumed cardiac cause are scarce.

Objective

To investigate the long-term survival of adult patients after surviving the initial hospital stay for an OHCA.

Data Sources

A systematic search of the EMBASE and MEDLINE databases was performed from database inception to March 25, 2021.

Study Selection

Clinical studies reporting long-term survival after OHCA were selected based on predefined inclusion and exclusion criteria according to a preregistered study protocol.

Data Extraction and Synthesis

Patient data were reconstructed from Kaplan-Meier curves using an iterative algorithm and then pooled to generate survival curves. As a separate analysis, an aggregate data meta-analysis was performed.

Main Outcomes and Measures

The primary outcome was long-term survival (>12 months) after OHCA for patients surviving to hospital discharge or 30 days after OHCA.

Results

The search identified 15 347 reports, of which 21 studies (11 800 patients) were included in the Kaplan-Meier-based meta-analysis and 33 studies (16 933 patients) in an aggregate data meta-analysis. In the Kaplan-Meier-based analysis, the median survival time for patients surviving to hospital discharge was 5.0 years (IQR, 2.3-7.9 years). The estimated survival rates were 82.8% (95% CI, 81.9%-83.7%) at 3 years, 77.0% (95% CI, 75.9%-78.0%) at 5 years, 63.9% (95% CI, 62.3%-65.4%) at 10 years, and 57.5% (95% CI, 54.8%-60.1%) at 15 years. Compared with patients with a nonshockable initial rhythm, patients with a shockable rhythm had a lower risk of long-term mortality (hazard ratio, 0.30; 95% CI, 0.23-0.39; P < .001). Different analyses, including an aggregate data meta-analysis, confirmed these results.

Conclusions and Relevance

In this comprehensive systematic review and meta-analysis, long-term survival after 10 years in patients surviving the initial hospital stay after OHCA was between 62% and 64%. Additional research is needed to understand and improve the long-term survival in this vulnerable patient population.

Pattern Changes in the Heart Rate Variability of Patients Undergoing Coronary Artery Bypass Grafting Surgery

Introduction

Coronary artery bypass grafting (CABG) with extracorporeal circulation is a key therapy for coronary artery disease (CAD). However, cardiovascular events and cardiac arrhythmias may still occur in these patients following surgery. Many studies have demonstrated a correlation between cardiac arrhythmias and heart rate variability (HRV). This study aimed to establish the temporal change pattern of HRV observed following CABG.

Methods

A prospective method was used to study 119 consecutive patients with stable CAD who were assessed using 24-hour Holter recordings 2 days before CABG and 1 week, 3 months, and 6 months after the surgery at Hanoi Heart Hospital from June 2016 to August 2018. Main results: All the time-domain and frequency-domain parameters of HRV decreased precipitately after CABG and were mostly recovered 3 months postoperatively. The percentage of decreased HRV before surgery was 28.6% and 51.8% after 7 days, 19.6% after 3 months, and 12.7% after 6 months. ASDNN and SDNN before and after surgery had the highest rates of change.

Conclusion

The early decrease in HRV observed 7 days after CABG may be related to the acute effects of the surgery. The recovery of HRV at 3 months after surgery, regardless of the preoperative state of the patients, implies that the autonomic nervous system (ANS) disorder may be improved at this time. At 6 months after surgery, the autonomic nervous injury was recovered in combination with improvement of reperfusion, resulting in improvement in almost all HRV indices compared with those indices preoperatively.