Thirty-day mortality risk associated with the postoperative nonresumption of angiotensin-converting enzyme inhibitors: a retrospective study of the Veterans Affairs Healthcare System.

Abstract

BACKGROUND: Angiotensin-converting enzyme inhibitors (ACE-Is) are a widely used class of cardiovascular medication. However, limited data exist on the risks of postoperative nonresumption of an ACE-I. OBJECTIVE: To evaluate the factors and 30-day mortality risks associated with the postoperative nonresumption of an ACE-I. DESIGN: A retrospective cohort study. SETTING: Veterans Affairs (VA) Healthcare System. PATIENTS: A total of 294,505 admissions in 240,978 patients with multiple preoperative prescription refills (>3) for an ACE-I who underwent inpatient surgery from calendar years 1999 to 2012. INTERVENTION: None. MEASUREMENTS: We classified surgical admissions based upon the timing of postoperative resumption of an ACE-I prescription from the day of surgery through postoperative days 0 to 14 and 15 to 30, and collected 30-day mortality data. We evaluated the relationship between 30-day mortality and the nonresumption of an ACE-I from postoperative day 0 to 14 using proportional hazard regression models, adjusting for patient- and hospital-level risk factors. Sensitivity analyses were conducted using more homogeneous subpopulations and propensity score models. RESULTS: Twenty-five percent of our cohort did not resume an ACE-I during the 14 days following surgery. Nonresumption of an ACE-I within postoperative day 0 to 14 was independently associated with increased 30-day mortality (hazard ratio: 3.44; 95% confidence interval: 3.30-3.60; P < 0.001) compared to the restart group. Sensitivity analyses maintained this relationship. CONCLUSIONS: Nonresumption of an ACE-I is common after major inpatient surgery in the large VA Health Care System. Restarting of an ACE-I within postoperative day 0 to 14 is, however, associated with decreased 30-day mortality. Careful attention to the issue of timely reinstitution of chronic medications such as an ACE-I is indicated.