Delay in coronary artery bypass grafting for STEMI patients improves hospital morbidity and mortality

The optimal timing of coronary artery bypass grafting (CABG) in patients with ST elevated acute myocardial infarction (STEMI) is unclear. The purpose of the study is to evaluate and compare the outcomes in STEMI patients who underwent CABG within the various time intervals within the first 7 days of either emergent or urgent hospital admission.

Patients aged 30 years old and older diagnosed with STEMI who underwent CABG within first 7 days after non-elective hospital admission were selected from the National Inpatient Sample 2010-2014 using the appropriate ICD-9-CM diagnosis and procedure codes. These patients were divided into 3 cohorts based on timing of surgery: within 24 h (group A), 2nd-3rd day (group B), and 4th-7th day (group C). The rates of postoperative complications, mortality, and postoperative hospital length of stay (LOS) were compared using the Chi-square test, multivariable logistic regression analysis, and Wilcoxon rank sum test.

A total of 5963 patients were identified: group A = 28.5%, group B = 36.1%, group C = 35.4%. Mean age overall was 63.1 ± 11.1 years; 76.9% were males and 72.9% were whites. Compared to groups B and C, patients in group A were more likely to develop cardiac complications (OR [odds ratio] =1.33, 95%CI [confidence interval] 1.12-1.59 and OR = 1.39, 95%CI 1.17-1.67, respectively) and respiratory complications (OR = 1.31, 95%CI 1.13-1.51 and OR = 1.53, 95%CI 1.32-1.78, respectively). They were also more likely to have renal complications (OR = 1.31, 95%CI 1.11-1.54) and bleeding (OR = 1.20, 95%CI 1.05-1.37) than patients in group B and had a similar tendency compared to group C. We did not find significant differences in the above complications between groups B and C. Postoperative stroke and sternal wound infection rates were similar between all three groups. In-hospital mortality was also higher in group A (8.2%) compared to group B (3.5%) and group C (2.9%, P < 0.0001 for both); differences between groups B and C were not significant. This was confirmed in the multivariable logistic regression analysis with controlling for age, gender, race, the Elixhauser Comorbidity Index, and complications (group A vs B: OR = 1.85, 95%CI 1.52-2.25; group A vs C: OR = 2.21; 95%CI 1.82-2.68). Patients in group A had a significantly longer postoperative LOS (median 7 days with IQR [interquartile range] 5-10 days) compared to those in group B (median 6 days, IQR 5-8 days) and group C (median 6 days, IQR 4-8 days; P < 0.0001 for both).

The results of this study show that despite the urgency and severity of STEMI, patients who undergo CABG within the first 24 h after non-elective hospital admission have increased hospital morbidity and mortality. These findings suggest that a delay in surgery beyond the first 24 h may be beneficial to patient outcomes. Furthermore, there is a significant cost effectiveness when the patients delay surgery because the hospital length of stay is reduced as well as the subsequent hospital costs.