Risk Factors Affecting Morbidity and Mortality in Open Repair of Infrarenal Abdominal Aortic Aneurysms: A Retrospective Cohort Study in the University of the Philippines - Philippine General Hospital.

Objectives: To describe the treatment outcomes of patients who underwent open repair of infrarenal abdominal aortic aneurysm (AAA) and to determine the risk factors affecting morbidity and mortality. Methods: Data were obtained from patients with infrarenal AAAs who underwent open surgical repair at the University of the Philippines-Philippine General Hospital (UP-PGH) from January 2013 to October 31, 2023. These patients' demographic and clinical profile, and treatment outcomes were evaluated using frequencies and percentages. Student's t-test and chi-square test were used for the inferential analysis. Multivariable logistic regression analysis was used to identify factors associated with in-hospital mortality and morbidity. Results: In this study, 131 patients underwent open surgical repair of AAA. 82.4% of the patients were males, and 45.8% were between 61-70 years old. The majority of them had hypertension (81.4%) and were smokers (75%). The mortality rate was 17.6%, while the morbidity rate was 35.9%. For elective operations, the mortality was 8.9%, and for ruptured aneurysms, it was 56.5%. Eleven factors associated with mortality included ruptured aneurysm (OR=11.5, 95%CI=4.1 to 32.2), decreased hemoglobin (OR=1.1, 95%CI=1.05 to 1.2), decreased hematocrit (OR=1.1, 95%CI=1.06 to 1.4), emergency surgery (OR=10.3, 95%CI=2.9 to 36.3), higher volume of blood loss (OR=1.5, 95%CI=1.5 to 1.9), higher red cell transfusion (OR=1.3, 95%CI=1.1-1.5), intraoperative cardiopulmonary (CP) arrest (OR=15.9, 95%CI=1.6 to 159.2), need for multiple inotropes (OR=2.7, 95%CI=1.5-4.8), intraoperative hypotension (OR=3.6, 95%CI=1.4-9.7), juxta-renal location (OR=5.0, 95%CI=1.2 to 10.0), and presence of any complication (OR=5.7, 95%CI=2.1-15.1). Seven factors associated with morbidity included ruptured aneurysm (OR=3.9, 95%CI=1.5 to 9.8), decreased preoperative hemoglobin (OR=1.2, 95%CI=1.1 to 1.4), decreased preoperative hematocrit (OR=1.5, 95%CI=1.1 to 1.7), elevated preoperative creatinine (OR=1.1, 95%CI=1.06 to 1.9), higher intra-operative blood loss (OR=1.4, 95%CI=1.1 to 1.6), higher red cell transfusion (OR=1.6, 95%CI=1.3-2.1), and preexisting chronic renal disease (OR=3.3, 95%CI=1.4 to 7.5). Other preoperative and intraoperative factors did not show a significant association with mortality or morbidity. Conclusion: The open repair of an infrarenal AAA is linked to high overall mortality (17.6%) and morbidity (35.9%). The mortality rate for elective repair was 8.9%, but it significantly increased to 56.5% in cases of ruptured aneurysms. Factors with very high Odds Ratio such as emergency surgery, ruptured aneurysm, cardiac arrests during surgery, complex juxtarenal anatomy, and postoperative complications can lead to a high chance of mortality. Healthcare professionals should be vigilant and focus on early detection and repair of abdominal aneurysms to prevent emergency surgery, rupture, and mortality. It is crucial to prevent acute kidney injury, acute respiratory failure, and pneumonia, as these are common complications of open repair.