Impact of the surgery schedule time on major cardiovascular complications after arterial vascular surgeries: a retrospective cohort

Abstract

Cardiovascular disease is a major cause of morbidity and mortality in patients undergoing arterial vascular surgery. These patients have a high risk of postoperative cardiac complications, especially because of the high prevalence of atherosclerosis. It was identified that patients at high risk are more likely to develop Perioperative Myocardial Injury (PMI) an important complication after cardiac and noncardiac surgeries. Also, these patients may develop other cardiac complications such as acute myocardial infarction, acute heart failure and arrhythmias, which are associated with increased hospitalization, cost and mortality. The knowledge of factors related to the occurrence of postoperative cardiac complications, including PMI, is essential to guarantee patients the best medical care. Recent studies suggest that the start time of the surgery may have an influence on postoperative cardiovascular complications, which could change medical practice by scheduling surgery in a time associated with lower risk. Therefore, since patients submitted to vascular surgeries have a higher risk of postoperative cardiac complications, this study seeks to evaluate the influence of daytime variation (morning vs. afternoon) on the incidence of PMI, postoperative cardiac complications and mortality in patients undergoing arterial vascular surgery. Objectives: The primary objective of this study is to compare the incidence of major cardiac complications, including acute myocardial infarction, arrhythmias, acute heart failure, and cardiovascular death during hospitalization of patients undergoing arterial vascular surgery in the morning (7h-12h) vs. afternoon (12h-17h). The secondary endpoint is to compare the incidence of Perioperative Myocardial Injury (PMI) in patients undergoing arterial vascular surgery in the morning with patients operated in the afternoon. Methodology: Retrospective cohort study, a sub-project of the ongoing study "Registry of Cardiovascular Complications Associated with Arterial Vascular Surgeries". This registry has been in progress since September 2012 and its primary objective is to document cardiovascular risk, intraoperative conditions and postoperative cardiac complications in patients submitted to arterial vascular surgeries who perform inter-consultation for cardiological evaluation. Exclusion criteria: Inability to obtain the time of surgery with the available documentation. PMI is defined as an absolute delta of hs-cTnT concentrations of ³ 14ng / L above baseline. Perioperative cardiac complications will be a combined outcome including Acute Myocardial Infarction, Acute Heart Failure, Arrhythmias and Cardiovascular Death. The exact time of the operation will be collected from the patient's anesthetic record. Before the analysis, we defined "morning" surgeries as the procedures in which the first incision occurred between 8:00 and 12:00; and for surgeries in the period of "late" surgeries in which the first incision occurred between 12:00 and 17:00. These time frames reflect the standard service hours of the study center and are in line with other studies. Statistical Analysis: Categorical variables will be presented by numbers and percentages, and compared by chi-square test (x2) or by Fisher's exact test. Continuous variables will be presented as medians and interquartile ranges, and compared by the Mann-Whitney test. Then, logistic regression models will be performed to verify if the time of operation is an independent predictor of PMI and cardiovascular complications. Significant clinical and laboratory variables in the univariate analysis will be included in the multivariate model. Statistical analyzes will be performed using SPSS software version 24.