Preoperative ß-Blocker Therapy and Stroke or Major Adverse Cardiac Events in Major Abdominal Surgery: A Retrospective Cohort Study.

BACKGROUND: Perioperative ß-blocker therapy has been associated with increased risk of stroke. However, the association between ß-blocker initiation before the day of surgery and the risk of stroke is unknown. The authors hypothesized there would be no association between preoperative ß-blocker initiation within 60 days of surgery or chronic ß-blockade (more than 60 days) and the risk of stroke in patients undergoing major abdominal surgery. METHODS: Data on elective major abdominal surgery were obtained from the IBM (USA) Truven Health MarketScan 2005 to 2015 Commercial and Medicare Supplemental Databases. Patients were stratified by ß-blocker dispensing exposure: (1) ß-blocker-naïve, (2) preoperative ß-blocker initiation within 60 days of surgery, and (3) chronic ß-blocker dispensing (more than 60 days). The authors compared in-hospital stroke and major adverse cardiac events between the different ß-blocker therapy exposures. RESULTS: There were 204,981 patients who underwent major abdominal surgery. ß-Blocker exposure was as follows: perioperative initiation within 60 days of surgery for 4,026 (2.0%) patients, chronic ß-blocker therapy for 45,424 (22.2%) patients, and ß-blocker-naïve for 155,531 (75.9%) patients. The unadjusted frequency of stroke for patients with ß-blocker initiation (0.4%, 17 of 4,026) and chronic ß-blocker therapy (0.4%, 171 of 45,424) was greater than in ß-blocker-naïve patients (0.2%, 235 of 155,531; P < 0.001). After propensity score weighting, patients initiated on a ß-blocker within 60 days of surgery (odds ratio, 0.90; 95% CI, 0.31 to 2.04; P = 0.757) or on chronic ß-blocker therapy (odds ratio, 0.86; 95% CI, 0.65 to 1.15; P = 0.901) demonstrated similar stroke risk compared to ß-blocker-naïve patients. Patients on chronic ß-blocker therapy demonstrated lower adjusted risk of major adverse cardiac events compared to ß-blocker-naïve patients (odds ratio, 0.81; 95% CI, 0.72 to 0.91; P = 0.007), despite higher unadjusted absolute event rate (2.6% [1,173 of 45,424] vs. 0.6% [872 of 155,531]). CONCLUSIONS: Among patients undergoing elective major abdominal surgery, the authors observed no association between preoperative ß-blocker initiation within 60 days of surgery or chronic ß-blocker therapy and stroke.