Major Gastrointestinal Complications after Elective Cardiac Surgery are Associated with Substantial Risk of Mortality and Excess Resource Use

J. Hadaya¹, N. Chervu², S. Kim³, J. Curry¹, N. Cho⁴, Y. Sanaiha⁵, R. J. Shemin³, P. Benharash^6
1David Geffen School of Medicine at UCLA, Los Angeles, California ²UCLA David Geffen School of Medicine, Los Angeles, California ³UCLA, Los Angeles, California ⁴David Geffen School of Medicine, Los Angeles, California ⁵University of California, Los Angeles, Los Angeles, California ⁶UCLA Division of Cardiac Surgery, Los Angeles, California

Purpose: Gastrointestinal (GI) complications such as mesenteric ischemia and bleeding are infrequent, but serious outcomes after cardiac surgery. However, prior studies have been limited by sample size and generalizability. We thus characterized the association of GI complications with mortality and resource use following elective cardiac surgery in a nationally representative cohort.

Methods: Adults undergoing elective coronary artery bypass grafting (CABG) and/or valve surgery were identified in the 2016-2019 National Inpatient Sample. The NIS approximates 97% of hospitalizations in the United States and contains cost data across all payer types. GI complications included ileus, bowel obstruction, GI bleeding, mesenteric ischemia, C. difficile colitis, acute liver injury, and pancreaticobiliary dysfunction. Generalized linear models were used to evaluate associations between GI complications and mortality or resource use (inpatient costs and length of stay, LOS). We secondarily studied management approaches utilized to address GI complications, including non-operative, endoscopic, interventional, and surgical intervention.

Results: Of 569,700 patients, 4.2% experienced postoperative GI complications, including ileus/bowel obstruction (2.4%), GI bleeding (0.5%), mesenteric ischemia (0.2%), acute liver injury (0.9%), C. difficile colitis (0.4%), and pancreaticobiliary dysfunction (0.3%). Patients with GI complications were older (67.6 vs 65.7 years, p< 0.001), more commonly male (74.1% vs 70.3%, p< 0.001), and had a higher Elixhauser Index (6.0 vs 4.6, p< 0.001). GI complications were most common following multi-valve (7.2%) or CABG-valve operations (6.2%) and least after isolated CABG (3.9%, p< 0.001). Patients with GI complications had higher unadjusted mortality compared to those without (14.4% vs 1.1%, p< 0.001). Mortality was greatest in patients with mesenteric ischemia (51.5%) or acute liver injury (41.1%) but remained high even for those experiencing ileus (5.0%) compared to controls (1.1%, p< 0.001). For most complications, patients who required invasive management had higher inpatient mortality rates, particularly bowel obstruction and C. difficile colitis (Table). After risk-adjustment, aggregate GI complications were associated with a 4.7-fold increase in odds of mortality (95% confidence interval, 4.4-5.0; Figure). Similarly, all GI complications contributed to greater LOS. Excess costs of each specific GI complication ranged from $14,000 for ileus to $62,200 for acute liver failure. GI complications contributed to over $360 million in national increased annual costs.

Conclusion: GI complications, ranging from ileus to mesenteric ischemia, are strongly associated with increased mortality, prolonged hospitalization, and costs of care following elective cardiac surgery. Furthermore, patients subsequently requiring invasive strategies had significantly higher rates of mortality. Increased vigilance and greater awareness of their impact on mortality may improve clinical outcomes.

Identify the source of the funding for this research project: None.