Impact of perioperative dexmedetomidine on long-term outcomes in older patients following cardiac surgery: follow-up of a randomized trial

BACKGROUND: Perioperative dexmedetomidine is reported to reduce complications and even in-hospital mortality after cardiac surgery. We therefore tested the hypothesis that perioperative dexmedetomidine may improve long-term outcomes after cardiac surgery. METHODS: This was long-term follow-up of a randomized trial. We enrolled 285 patients aged 60 years or older who were scheduled for elective cardiac surgery. Patients were randomized to receive either dexmedetomidine or placebo (normal saline) during and early after surgery. Follow-up was conducted for up to 6 years post-surgery. The primary endpoint was overall survival. Secondary outcomes included major adverse cardiovascular events (MACE)-free and hospital-free survivals, as well as cognitive function and quality of life in 6-year survivors. RESULTS: All 285 patients were included in final analysis. Median follow-up duration was 80 months (interquartile range 30 to 80). Overall survival did not differ between the two groups: there were 18 deaths (12.6%) with placebo versus 22 deaths (15.5%) with dexmedetomidine; hazard ratio (HR) 1.22, 95% CI 0.65 to 2.27, p = 0.418. MACE-free survival was 23 (16.1%) with placebo versus 24 (16.9%) with dexmedetomidine; HR 1.03, 95% CI 0.58 to 1.83, P = 0.911. Hospital-free survival was 39 (27.3%) with placebo versus 42 (29.6%) with dexmedetomidine; HR 1.04, 95% CI 0.67 to 1.61, P = 0.853. Among 6-year survivors, the scores of cognitive function and quality of life were similar between groups. CONCLUSIONS: We found that, for older patients undergoing elective cardiac surgery, dexmedetomidine administered during and early after surgery did not alter overall and MACE-free survivals, as well as long-term cognitive function and quality of life. However, considering the underpowered sample size and non-negligible loss to follow-up rate, our results need further confirmation. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03289325 (September 20, 2017).