Background: Conflicting results are reported about daytime variation on mortality and cardiac outcomes after non-cardiac surgeries. In this cohort study, we evaluate whether the period of the day in which surgeries are performed may influence all-cause mortality and cardiovascular outcomes in patients undergoing non-cardiac arterial vascular procedures. Methods: 1,267 patients who underwent non-cardiac arterial vascular surgeries between 2012 and 2018 were prospectively included in our cohort and categorized into two groups: morning (7 a.m. to 12 a.m., 79%) and afternoon/night (12:01 p.m. to 6:59 a.m. in the next day, 21%) surgeries. Primary endpoint was all-cause mortality within 30 days and one year. Secondary endpoints were the incidence of perioperative myocardial injury/infarction (PMI), and the incidence of major adverse cardiac events (MACE, including acute myocardial infarction, acute heart failure, arrhythmias, cardiovascular death) at hospital discharge. Results: After adjusting for confounders in the multivariable Cox proportional regression, all-cause mortality rates at 30 days and one year were higher among those who underwent surgery in the afternoon/night (aHR 1.6 [95%CI 1.1–2.3], P = 0.015 and aHR 1.7 [95%CI 1.3–2.2], P < 0.001, respectively). Afternoon/night patients had higher incidence of PMI (aHR 1.4 [95%CI 1.1–1.7], P < 0.001). There was no significant difference in the incidence of MACE (aHR 1.3 [95%CI 0.9–1.7], P = 0.074). Conclusions: In patients undergoing arterial vascular surgery, being operated in the afternoon/night was independently associated with increased all-cause mortality rates and incidence of perioperative myocardial injury/infarction.
Cardiovascular disease is a major postoperative cause of morbidity and mortality in patients submitted to arterial vascular surgery.
In the perioperative period, acute myocardial infarction (AMI), acute heart failure, cardiac arrhythmias and perioperative myocardial injury/infarction (PMI) are associated with increased length of hospital stay, elevated costs and increased mortality [[
Overall, cardiovascular events can be influenced by the circadian cycle, with higher rates and worse outcomes of events occurring in the early morning [[
On the other hand, several studies have shown worse outcomes in surgeries performed at weekends or holidays even after correcting for surgeon experience. The smaller levels of staff, consulting services and diagnostics exams available at night or weekends might result in more surgery complications [[
In non-cardiac arterial vascular surgeries, there is no conclusive data about the association of cardiovascular complications and the period of the day in operating room. Our goal is to evaluate whether the period of the day in which surgeries are performed may influence all-cause mortality and major cardiac complications in patients undergoing non-cardiac arterial vascular interventions.
This is part of a prospective cohort registry including consecutive patients undergoing non-cardiac arterial vascular surgery between 2012 and 2018 at Hospital das Clínicas, University of São Paulo Medical School, São Paulo, Brazil, for whom a preoperative cardiologic consultation was requested. Cardiology consultation and perioperative evaluation is provided in less than 24 hours in our hospital. For this study, we excluded patients from whom it was not possible to perform perioperative cardiovascular evaluation or to obtain time of the surgery with the available documentation. We included patients undergoing all arterial vascular surgeries: open or endovascular (for aorta, peripheral artery, visceral artery, and carotid artery diseases and amputations due to limb ischemia), emergent, urgent, or elective. Of note, in the present study, urgent/emergency procedures were considered interventions for acute onset pathologies or clinical deterioration without previously schedule or outpatient evaluation that were able to receive perioperative cardiac evaluation.
Baseline characteristics of the patients were obtained from the clinical and laboratorial records registered in the preoperative cardiologic consultation. Perioperative surveillance with high-sensitive cardiac Troponin T (hs-cTnT) was performed, according to current guidelines [[
Variables of interest from all screened patients are registered in a dedicated prospective database. Since the Revised Cardiac Risk Index already contains heart failure as one of its variables, chronic heart failure was not included in the multivariable analysis.
The exact time of surgery was obtained from the anesthetic record. In cases of impossibility to obtain the anesthetic record, the exact time of the surgery was obtained from the records of the nursing staff of the operating room (time of entry into the operating room).
This study was performed in line with the principles of the Declaration of Helsinki. Study protocol was approved by the Local Research Ethics Committee of the Hospital das Clínicas, University of São Paulo Medical School, Brazil (approval number: 30217414.5.0000.00068). The need for Informed Consent was waived by the ethics committee.
We adhered to the STROBE guidelines for observational studies (S1 Table).
Before the analysis, we defined surgeries in the "morning" period as procedures for which the first incision occurred between 7 a.m. and 12 a.m.; and surgeries in the "afternoon/night" period as procedures for which the first incision occurred between 12:01 p.m. and 6:59 a.m. of the next day. These time intervals reflect the Hospital work shifts of the surgical at our study center and are an example of the pattern of categorization between morning and afternoon surgeries previously described in the literature [[
Primary endpoint was all-cause mortality within 30 days and one year follow-up. 30-days follow-up was made by in-hospital stay registries, postoperative consultation data or telephone calls. One year follow-up for all-cause mortality was made by telephone calls, patient's charts and local death registries (with the appropriate death date confirmed).
Secondary endpoints included the incidence of perioperative myocardial injury/infarction (PMI) and the incidence of major adverse cardiac events (MACE). PMI and MACE were followed-up until hospital discharge by in-hospital stay registries.
PMI was defined as an absolute delta of hs-cTnT concentrations ≥ 14ng/L above the baseline concentrations within 3 days after the operation. In the absence of a preoperative hs-cTnT, PMI was defined as a delta ≥ 14ng/L between two postoperative concentrations [[
MACE was a composite endpoint, including acute myocardial infarction, acute heart failure, new or decompensated arrhythmias requiring treatment, and cardiovascular death within 30 days after the surgery, which were defined according to the following criteria:
- Acute myocardial infarction (AMI): defined according to the 4th universal definition of AMI [[
18 ]]. AMI is diagnosed in the presence of elevation and decrease of myocardial necrosis markers (troponin) above reference value associated with at least one of the following criteria: I. Symptoms of myocardial ischemia; II. Electrocardiographic signs compatible with ischemia; III. New segmental change on the echocardiogram or evidence of myocardial injury in imaging studies; IV. Coronary angiography with acute coronary lesion. All AMI cases were adjudicated by two independent cardiologists. - Acute Heart Failure: diagnosed by cardiologist or attending physician, using clinical symptoms, physical examination findings, chest radiography, BNP or serum NT-proBNP and echocardiography, according to current guidelines [[
20 ]]. - Arrhythmias (atrial fibrillation/flutter, supraventricular tachycardia, ventricular tachycardia): diagnosed when considered clinically significant, i.e., drug therapy or electrical cardioversion.
- Cardiovascular death: deaths were classified as cardiovascular or non-cardiovascular according to guidelines. Deaths were considered cardiovascular, unless evidence of a non-cardiovascular cause was documented [[
22 ]].
Categorical variables were presented by numbers and percentages (frequencies) and were compared using Pearson's Chi-squared test with Yates' continuity. Continuous variables were presented as medians and interquartile ranges and were compared using the Mann-Whitney test (tabular results, unpaired), assuming non normal distribution.
All-cause mortality was described between patients operated in the morning vs in the afternoon/night in a descriptive analysis, with P-values calculated by Log-Rank test, and Hazard-Ratios (HR) with 95% Confidence Intervals (CI) calculated by Univariate Cox regression analysis. Both 30 days and one year follow-up were considered in the analysis.
PMI was described between patients operated in the morning vs in the afternoon/night in a descriptive analysis, with P-values calculated by Pearson's Chi-squared test with Yates' continuity (x2 test), and Odds-Ratio (OR) with 95% CI calculated by Baptista-Pike method. MACE were described between patients operated in the morning vs in the afternoon/night in a descriptive analysis, with P-values calculated by Log-Rank test, and Hazard-Ratios (HR) with 95% Confidence Intervals (CI) calculated by Univariate Cox regression analysis.
For the multivariable analysis, we calculated the adjusted Hazard-Ratios (aHR) and 95% CI using Multivariate Cox regression analysis to adjust for confounding variables. Our Regression Model and population was considered strong enough to estimate the effect size of each variable/confounder, allowing to identify the interaction effects between treatment and confounders. Significant clinical and laboratory variables in the univariable analysis were included in the multivariable model. Based on the number of events and the consensus of requiring 10 events for each independent variable, we could address all variables with a P < 0.05 in the univariable analysis. Loss of follow-up and missing data are indicated in the descriptive text before tables and figures. No imputation was performed for missing values.
The statistical significance level considered was 95% (P < 0.05). Statistical analyses were performed using the software R for Windows, R Core Team (2020—R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://
Sensitivity Analysis—Since urgent/emergency surgeries are more frequent in the night period they could be correlated variables. To avoid confounding results a sensitivity analysis was made considering only the population undergoing urgent/emergency surgery, submitting them to the same statistical analysis performed in the main cohort.
Between 2012 and 2018, 1,296 patients went to preoperative cardiologic consultation before arterial vascular surgery (S1 Fig), of which 29 patients were excluded, leaving 1,267 for inclusion in our cohort (S2 Fig).
Of the 1,267 patients, 1,002 (79.1%) underwent arterial vascular surgery in the morning and 265 (20.9%) in the afternoon/night period (Table 1). Urgent/emergency surgeries were more prevalent in the afternoon/night group. Male gender patients were more prevalent in both groups with a median age of 68 years. Patients in the afternoon/night group had more comorbidities such as diabetes mellitus requiring insulin, hypertension, chronic heart failure, had more preoperative use of clopidogrel, and less use of aspirin. Finally, the morning group had higher hemoglobin levels.
Graph
Table 1 Baseline characteristics of the 1,267 patients in the cohort.
All Patients Afternoon surgery Morning surgery P-value n = 1267 n = 265 n = 1002 n (%) n (%) n (%) Male gender, n (%) 881 (69.5%) 176 (66.4%) 705 (70.4%) 0.244 Age (years), median (IQR) 68 [61–75] 68 [61.5–75] 68 [61–75] 0.937 Diabetes mellitus, n (%) No insulin, n (%) 330 (26.0%) 80 (30.2%) 250 (25.0%) 0.068 Insulin, n (%) 160 (12.6%) 52 (19.6%) 108 (10.8%) Smoking, n (%) Smoker, n (%) 265 (20.9%) 54 (20.4%) 211 (21.1%) 0.587 Former smoker, n (%) 668 (52.7%) 124 (46.8%) 544 (54.3%) Hypertension, n (%) 1079 (85.2%) 235 (88.7%) 844 (84.2%) 0.087 Coronary artery disease, n (%) 482 (38.0%) 103 (38.9%) 379 (37.8%) 0.810 COPD, n (%) 78 (6.2%) 17 (6.4%) 61 (6.1%) 0.957 Chronic heart failure, n (%) 219 (17.3%) 60 (22.6%) 159 (15.9%) 0.013 Stroke/transient ischemic attack, n (%) TIA, n (%) 52 (4.1%) 8 (3.0%) 44 (4.4%) 0.130 Stroke, n (%) 265 (20.9%) 70 (26.4%) 195 (19.5%) Urgent/Emergency Surgery, n (%) 478 (37.7%) 181 (68.3%) 297 (29.6%) < 0.001 Revised cardiac risk index I, n (%) 94 (7.4%) 32 (12.1%) 62 (6.2%) 0.006 II, n (%) 480 (37.9%) 90 (34.0%) 390 (38.9%) III, n (%) 391 (30.9%) 75 (28.3%) 316 (31.5%) IV, n (%) 302 (23.8%) 68 (25.7%) 234 (23.4%) Preoperative Medications ASA, n (%) 1014 (80.0%) 200 (75.5%) 814 (81.2%) 0.093 Clopidogrel, n (%) 93 (7.3%) 30 (11.3%) 63 (6.3%) 0.006 Statins, n (%) 1164 (91.9%) 219 (82.6%) 945 (94.3%) < 0.001 ACEI, n (%) 401 (31.6%) 82 (30.9%) 319 (31.8%) 0.962 Angiotensin receptor blockers, n (%) 293 (23.1%) 57 (21.5%) 236 (23.6%) 0.619 Betablockers, n (%) Started before surgery, n (%) 50 (3.9%) 7 (2.6%) 43 (4.3%) 0.392 Chronic, n (%) 576 (45.5%) 111 (41.9%) 465 (46.4%) Withdraw before surgery, n (%) 26 (2.1%) 7 (2.6%) 19 (1.9%) Laboratory assessment Creatinine (mg/dL), median [IQR] 1.11 [0.88–1.42] 1.08 [0.84–1.46] 1.12 [0.89–1.41] 0.403 Hemoglobin (g/dL), median [IQR] 12.80 [11.10–14.20] 12.20 [9.93–13.80] 13.00 [11.40–14.30] < 0.001
1 IQR: interquartile range; COPD: chronic obstructive pulmonary disease; TIA: transient ischemic attack; ASA: acetylsalicylic acid; ACEI: Angiotensin-converting enzyme inhibitors.
Of 1,267 patients included in the cohort, one year follow-up was complete in 91,9%. Overall, 152 (12.0%) patients died after 30 days and 260 (20.5%) after one-year (Table 2). Significant increase in all-cause mortality in the afternoon/night surgery group was observed after 30 days (HR 2.29 [95%CI 1.65–3.19], P-value < 0.001) and one year (HR 2.38 [95%CI 1.85–3.07], P-value < 0.001).
Graph
Table 2 All-cause mortality after 30 and one year of follow-up and MACE.
All Patients Afternoon surgery Morning surgery HR (95%CI) P-value n = 1267 n = 265 n = 1002 n (%) n (%) n (%) All-cause mortality 30 days 152 (12.0%) 55 (20.8%) 97 (9.7%) 2.29 [1.65–3.19] < 0.001 MACE Hospital Discharge 302 (23.8%) 97 (36.6%) 205 (20.5%) 1.93 [1.52–2.46] < 0.001 Cardiovascular Death 73 (5.8%) 20 (7.5%) 53 (5.3%) 1.42 [0.85–2.38] 0.200 Myocardial infarction 147 (11.6%) 48 (18.1%) 99 (9.9%) 1.87 [1.32–2.64] < 0.001 Acute heart failure 132 (10.4%) 59 (22.3%) 73 (7.3%) 3.32 [2.35–4.68] < 0.001 Arrhythmia 72 (5.7%) 24 (9.1%) 48 (4.8%) 1.94 [1.19–3.17] 0.007 All Patients Afternoon surgery Morning surgery HR (95%CI) P-value n = 1164 n = 238 n = 926 n (%) n (%) n (%) All-cause mortality one year 260 (20.5%) 92 (34.7%) 168 (16.8%) 2.38 [1.85–3.07] < 0.001
2 MACE: major adverse cardiac events; HR: hazard ratio.
After adjusting for confounding variables in the multivariable analysis, all-cause mortality at 30 days remained higher among those who underwent surgery in the afternoon/night period (aHR 1.6 [95%CI 1.1–2.3], P = 0.015; Table 3). The increased mortality persisted after one year in those that had surgery in the afternoon/night (aHR 1.7 [95%CI 1.3–2.2], P < 0.001; Table 3). Mortality curves are depicted in Fig 1.
Graph: Fig 1 All-cause mortality after arterial vascular surgery.Groups according to the start time of the procedure in the cohort population in 30 days (A) and one-year (B) follow-up.
Graph
Table 3 Multivariable analysis by Cox regression model—All-cause mortality.
Adjusted HR P-value Adjusted HR P-value (95%CI) (95%CI) 30 days One year All-cause mortality Afternoon surgery 1.58 (1.09–2.29) 0.015 1.68 (1.27–2.22) < 0.001 Urgent/Emergency Surgery 1.51 (1.02–2.23) 0.041 1.34 (0.99–1.81) 0.055 Revised Cardiac Risk Index I - - - - Revised Cardiac Risk Index II 1.54 (0.80–2.98) 0.196 1.22 (0.77–1.95) 0.395 Revised Cardiac Risk Index III 1.72 (0.87–3.39) 0.118 1.28 (0.79–2.08) 0.323 Revised Cardiac Risk Index IV 1.81 (0.92–3.58) 0.086 1.67 (1.04–2.70) 0.035 Clopidogrel 0.59 (0.28–1.23) 0.157 0.84 (0.52–1.37) 0.489 Statins 0.64 (0.39–1.05) 0.077 0.69 (0.46–1.03) 0.071 Hemoglobin (g/dL) 0.85 (0.78–0.92) < 0.001 0.81 (0.76–0.86) < 0.001
3 aHR: adjusted hazard ratio.
Patients with higher Revised Cardiac Risk Index classifications had higher incidence of all-cause mortality. On the other hand, higher hemoglobin levels were associated with decreased incidences of mortality in both 30 days and one year.
For this analysis, 88 (6.9%) patients did not have two consecutive values of hs-cTnT for the evaluation of PMI and were considered missing data. Overall, 351 (27.7%) patients had PMI after surgery. The incidence of PMI was higher in patients of the afternoon/night group than in patients of the morning group: 37.4% versus 25.1%, respectively (OR 1.77 [95%CI 1.34–2.36], P-value < 0.001).
In the multivariable analysis, surgeries that occurred in the afternoon/night group were also independently associated with higher PMI incidence (Table 4). Urgent/emergency surgeries were associated with higher PMI rates. Also, patients with higher Revised Cardiac Risk Index classifications had higher incidence of PMI. Preoperative clopidogrel was associated with lower incidence of PMI.
Graph
Table 4 Multivariable analysis by Cox regression model—PMI and MACE.
Adjusted HR P-value (95%CI) PMI Afternoon surgery 1.35 (1.05–1.74) 0.020 Urgent/Emergency Surgery 1.78 (1.39–2.28) < 0.001 Revised Cardiac Risk Index I - - Revised Cardiac Risk Index II 2.23 (1.30–3.84) 0.004 Revised Cardiac Risk Index III 2.68 (1.55–4.65) < 0.001 Revised Cardiac Risk Index IV 3.14 (1.81–5.44) < 0.001 Clopidogrel 0.35 (0.20–0.62) < 0.001 Statins 0.64 (0.44–0.93) 0.021 Hemoglobin (g/dL) 0.93 (0.88–0.97) 0.003 MACE Afternoon surgery 1.27 (0.98–1.66) 0.074 Urgent/Emergency Surgery 1.71 (1.30–2.26) < 0.001 Revised Cardiac Risk Index I - - Revised Cardiac Risk Index II 1.39 (0.89–2.18) 0.152 Revised Cardiac Risk Index III 1.45 (0.91–2.31) 0.117 Revised Cardiac Risk Index IV 1.66 (1.04–2.65) 0.034 Clopidogrel 0.73 (0.46–1.17) 0.193 Statins 0.44 (0.31–0.61) < 0.001 Hemoglobin (g/dL) 0.85 (0.80–0.90) < 0.001
4 aHR: adjusted hazard ratio. PMI: perioperative myocardial injury/infarction. MACE: major adverse cardiac events.
At hospital discharge, the incidence MACE was higher in the afternoon/night surgery group (Table 2). Surgeries occurring in the afternoon/night period were not independently associated with increased MACE after correction for confounders (Table 4). However, urgent/emergency surgeries and higher Revised Cardiac Risk Index classifications were associated with elevated occurrence of MACE. The use of preoperative statins and higher hemoglobin levels were associated with lower rates of MACE.
Of the total, 478 patients underwent urgent/emergency surgery: 181 (37.9%) during the morning and 297 (62.1%) during the afternoon/night period. Considering only urgent/emergency surgery population, significant increase in all-cause mortality in the afternoon/evening surgery group was observed after 30 days (HR 2.57 [95% CI 1.69–3.93], P value < 0.001) and one year (HR 2.43 [95% CI 1.75–3.37], P value < 0.001). After multivariate analysis, 30-day all-cause mortality was higher in the afternoon/night period (aHR 2.43 [95%CI 1.54–3.83], P = < 0.001), as well as one year mortality (aHR 2.35 [95%CI 1.65–3.33], P = < 0.001)–(S3 Fig).
The incidence of PMI in the urgent/emergency surgery group was also higher in patients operated in the afternoon/evening period: 44.2% versus 33.0%, respectively (OR 1.82 [95%CI 1.22–2.71], P- value = 0.003). In the multivariate analysis, urgent/emergency surgeries performed in the afternoon/evening presented independent association with the incidence of PMI (aHR 1.4 [95%CI 1.03–1.91], P = 0.03). After 30 days, the incidence of MACE in urgent/emergency surgery group was higher in the afternoon/evening surgery population. Surgeries performed in the afternoon/evening period were independently associated with increased MACE after correction for confounding factors in the multivariable analysis (aHR 1.51 [95%CI 1.10–2.06], P = 0.010).
In this prospective cohort study, we aimed to investigate whether the period of the day in which surgeries are performed may influence all-cause mortality, perioperative myocardial injury/infarction (PMI) and major adverse cardiac events (MACE) in patients undergoing non-cardiac arterial vascular procedures. We observed that surgeries performed in the afternoon/night period were associated with higher all-cause mortality at 30 days and one year and elevated PMI incidence (Fig 2). The incidence of MACE at hospital discharge, however, was not different between morning and afternoon/night surgical groups.
Graph: Fig 2 Graphical abstract.In patients submitted to arterial vascular surgery, being operated in the afternoon/night period was independently associated with increased mortality rates and higher incidence of PMI. O: outcomes. T: time of follow-up.
The higher mortality rates in the afternoon/night group during follow-up presented in our study was not previously described. While a recent study by du Fay de Lavallaz et al [[
The disparities between the studies might be explained because of different patient populations, human factors, and structural procedures. Compared with the other two cohorts, our patients had more comorbidity such as diabetes, hypertension, coronary artery disease, chronic heart failure and cerebrovascular arterial disease. Regarding the type of the surgery, our study focused on a specific type of higher risk surgery: arterial vascular surgeries. Also, urgent/emergency procedures were more prevalent than in the other studies. We decided to include urgent/emergency surgeries in our cohort because they represent a significant share of all vascular surgeries performed in our service. Therefore, we aimed to evaluate the same endpoints of elective surgeries to have a perception of how they would perform. Although the proportion of urgent/emergency surgeries could weight in the Cox Regression, we considered that our Regression Model and population was strong enough to estimate the effect size of each variable/confounder. At last, our study population is based on a tertiary health care center to which patients are usually referred when they have a more severe vascular condition or important cardiac or noncardiac comorbidities, often arriving at a poor clinical condition. Those combined situations could explain the high all-cause mortality rate overcoming the impact of MACE in the perioperative period.
Despite our standardized perioperative care management, it is possible that other non-measured factors might have influenced the outcomes, such as staffing, care units and other human factors. Not only patients' characteristics and clinical aspects are responsible for time distribution; operating issues and surgeries delay could affect the schedule of the surgeries, which were not assessed in our study. A study by van Zaane et al could not identify association between in-hospital mortality and the time of the day in urgent non-cardiac surgeries [[
Our finding of daytime variation on PMI incidence is also different from the reported on previous cohorts in non-cardiac surgery [[
Other secondary finding of our study was the association between preoperative use of statins and better prognosis of MACE at hospital discharge. Our cohort corroborate data from previous studies in which statins demonstrated to be effective in the prevention of cardiovascular events after vascular surgeries [[
Our study has some limitations. First, our study population involves patients from a tertiary health care center to which patients are usually referred when they have a more severe vascular condition or important cardiac or noncardiac comorbidities. We included in the cohort patients for whom cardiac consultation was requested, and although it is a common practice at our institution for vascular surgeons to request cardiac evaluation for all patients, we may have missed patients in the lower risk strata. In clinical practice, low risk patients according to anesthesiology evaluation are often directly sent to surgical theater without further consultation. Given the nature of the present study (retrospective analysis of prospective collected data) we don't have the number of patients operated without cardiac consultation, but we estimate a small number of cases that could not influence the final results of the present study. Second, despite having used a regression model to adjust for confounders, we must consider that other unmeasured confounders may have interacted with the results. Third, our study was made based on a specific type of surgery: arterial vascular surgeries. Although this enhances the power of the study and avoid possible confounders, such as different perioperative risks, our findings cannot be extrapolated for other types of surgery. Fourth, although we have considered urgent/emergency surgeries in our analysis, we have not measured the level of stress or tiredness and the level of experience of the healthcare professionals who performed the surgeries, which may add some degree of bias in our study.
The association between mortality rates, PMI, MACE and the period of the day in which surgeries are performed seem to be a promising field of study. The results of this cohort may lead to readjustments of simple medical procedures (such as determining the best time for the surgical procedure, which may indicate better prognosis) or in monitoring the patient (for example, determining how the multidisciplinary follow-up of a high-risk cardiovascular patient undergoing vascular surgery should be), simple measures that may have an impact on improving clinical practice. The cardioprotective strategy based only on the time of surgery indicates an economical and easy to implement measure for the prevention of postoperative cardiovascular complications.
In high-risk patients submitted to arterial vascular surgeries, being operated in the afternoon/night period was independently associated with increased all-cause mortality rates and higher incidence of PMI. We could not identify any influence of the period of the day in which surgeries are performed on the incidence of MACE.
S1 Fig. Distribution by surgery type from morning and afternoon/night groups.
AAAE = Abdominal Aortic Aneurysm Endovascular; AAAO/H = Open or Hybrid Abdominal Aortic Aneurysm; TAAEO/H = Thoracic Aortic Aneurysm Endovascular, Open or Hybrid; LLRO/E = Open or Endovascular Lower Limb Revascularization; EC = Endovascular Carotid; OC = Open Carotid; AMPUT = Amputations; OTHERS = Open or Endovascular Visceral Arteries and Other Procedures.
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S2 Fig. Study population.
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S3 Fig. Mortality in urgent/emergency surgeries.
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S1 Table. STROBE statement—Checklist of items that should be included in reports of cohort studies.
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By Thiago Artioli; Danielle Menosi Gualandro; Francisco Akira Malta Cardozo; María Carmen Escalante Rojas; Daniela Calderaro; Pai Ching Yu; Ivan Benaduce Casella; Nelson de Luccia and Bruno Caramelli
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