Advanced chronic kidney disease after surgery and the contribution of acute kidney disease: a national observational cohort study.

BACKGROUND: Limited knowledge exists regarding long-term renal outcomes after noncardiac surgery. This study investigated the incidence of, and risk factors for, developing advanced chronic kidney disease (CKD) and major adverse kidney events within 1 yr of surgery in a nationwide cohort. METHODS: Adults without renal dysfunction before noncardiac surgery in Sweden were included between 2007 and 2013 in this observational multicentre cohort study. We analysed data from a national surgical database linked to several national and quality outcome registries. Associations of perioperative risk factors with advanced CKD (estimated glomerular filtration rate [eGFR] <30 ml min-1 1.73 m-2) and major adverse kidney events within 1 yr (MAKE365, comprising eGFR <30 ml min-1 1.73 m-2, chronic dialysis, death) were quantified. RESULTS: Of 237,124 patients, 1597 (0.67%) developed advanced CKD and 16,789 (7.1%) developed MAKE365. Risk factors for advanced CKD included higher ASA physical status, urological surgery, extended surgical duration, prolonged postoperative hospital stay, repeated surgery, and postoperative use of renin-angiotensin-aldosterone system blockers. Advanced acute kidney disease (AKD) (eGFR <30 ml min-1 1.73 m-2 within 90 postoperative days) occurred in 1661 (0.70%) patients and was associated with advanced CKD (subdistribution hazard ratio [SHR] 44.5, 95% confidence interval [CI] 38.7-51.1) and MAKE365 (hazard ratio [HR] 6.60, 95% CI 6.07-7.17). Among patients with advanced AKD after surgery 36% developed advanced CKD at 1 yr after surgery and 51% developed MAKE365. CONCLUSIONS: Advanced CKD within 1 yr after surgery is uncommon but clinically important in patients without preoperative renal dysfunction. Advanced AKD after surgery constitutes a major risk factor for advanced CKD and MAKE365.

Days at home alive after major surgery in patients with and without diabetes: an observational cohort study.

OBJECTIVE: We hypothesized that days at home alive up to 30 days after surgery (DAH30), a novel patient-centered outcome metric, as well as long-term mortality, would be impaired in patients with type 1 or 2 diabetes mellitus (DM) undergoing major surgery. METHODS: This cohort study investigated patients > 18 years with and without DM presenting for major non-cardiovascular, non-ambulatory surgical procedures at 23 hospitals in Sweden between 2007 and 2014. We identified 290,306 patients. Data were matched with various quality registers. The primary outcome was the composite score, DAH30. The secondary outcome was mortality from 31 to 365 days. Using multivariable logistic regression, significant independent risk factors influencing the primary and secondary outcomes were identified, and their adjusted odds ratios were calculated. RESULTS: Patients with DM type 1 and 2 had significantly lower DAH30 as compared to non-diabetics. Patients with DM were older, had higher co-morbid burden, and needed more emergency surgery. After adjustment for illness severity and age, the odds of having a DAH30 less than 15, indicating death and/or complications, were significantly increased for both type 1 and type 2 diabetes. In the year after surgery, DM patients had a higher mortality as compared to those without diabetes. CONCLUSIONS: The results of this large cohort study are likely broadly generalizable. To optimize patient and societal outcomes, specific perioperative care pathways for patients with diabetes should be evaluated.

Incidence and risk factors of peri-operative stroke in major non-cardiovascular, non-neurologic surgery-A retrospective register-based cohort study.

BACKGROUND: Peri-operative stroke is a rare but serious surgical complication. Both overt and covert stroke, occurring in approximately 0.1% and 7% of cases, respectively, are associated with significant long-term effects and increased morbidity. METHODS: Retrospective register data for patients >18 years old, presenting for major non-cardiovascular, non-neurosurgical and non-ambulatory surgical procedures at 23 hospitals in Sweden between 2007 and 2014 was collected and linked with various quality registers. The primary outcome was stroke within 30 days from surgery. Using multivariable logistic regression, significant independent risk factors influencing the primary outcome were identified and their adjusted odds ratios (ORs) were calculated. Mortality was assessed, along with the composite score of days alive and at home within 30 days after surgery (DAH 30). RESULTS: In total, 318,017 patients were included, with 687 (0.22%) suffering a stroke within 30 days of surgery. The strongest significant risk factors included: increasing ASA-class (OR [95% confidence interval, CI]: 2.23 [1.53-3.36], 3.91 [2.68-5.93] and 7.82 [5.03-12.5] for ASA 2, 3 and 4, respectively) and age (OR [95% CI]: 4.47 [2.21-10.3], 9.9 [5.15-22.1], 16.3 [8.48-36.5] and 21 [10.6-48.1], for age 45-59, 60-74, 75-89 and >90, respectively), along with non-elective procedures, male gender and a history of cerebrovascular disease (OR [95%]: 2.72 [2.25-3.27]). Mortality was increased and DAH 30 was reduced in patients suffering a stroke. CONCLUSIONS: Increasing ASA-class and age was clearly associated with an increased risk of peri-operative stroke, which in turn was associated with increased mortality and poorer outcome. Detailed pre-operative risk stratification and individualised peri-operative management could potentially improve patient-centred outcomes and, in turn, have positive implications for public health.

Risk factors for new antidepressant use after surgery in Sweden: a nationwide, observational cohort study.

Background: Whilst somatic complications after major surgery are being increasingly investigated, the research field has scarce data on psychiatric outcomes such as postoperative depression. This study evaluates the impact of patient and surgical factors on the risk of depression after surgery using the proxy measure of prescribed and collected antidepressants. Methods: An observational, registry-based, national multicentre cohort study of individuals ≥18 yr of age who underwent noncardiac surgery between 2007 and 2014. Exclusion criteria included history of antidepressant use defined by collection of a prescription within 5 yr before surgery. Participants were identified using a surgical database from 23 Swedish hospitals and data were linked to National Board of Health and Welfare registers for collection of prescribed antidepressants. Descriptive statistics were used for baseline data and logistic regression for predictive factors. Results: Of 223 617 patients, 4.9% had a new prescription of antidepressants collected 31-365 days after surgery. Antidepressant prescription was associated with increasing age, female sex, and more comorbidities. The incidence of antidepressant prescription was highest after neurosurgery, vascular, and thoracic surgery. Affective and anxiety disorders were risk factors. In the whole cohort and within the aforementioned surgical subtypes, acute and cancer surgery increased the risk of antidepressant prescription. Conclusions: This study brings novel insights to the epidemiology of postoperative antidepressant treatment in antidepressant-naive patients. One in 20 postoperative patients are prescribed antidepressants but with knowledge of risk factors, interventional strategies can be tested.

New prolonged opioid consumption after major surgery in Sweden: a population-based retrospective cohort study.

OBJECTIVE: Given that long-term opioid usage is an important problem worldwide and postsurgical pain is a common indication for opioid prescription, our primary objective was to describe the frequency of new prolonged opioid consumption after major surgery in Sweden and, second, to evaluate potential associated risk factors. DESIGN: Cohort study including data from 1 January 2007 to 31 December 2014. Data regarding surgical procedures, baseline characteristics and outcomes was retrieved from the Orbit surgical planning system, the Swedish national patient register and the Swedish cause of death register. SETTING: Observational multicentre cohort study with data from 23 Swedish hospitals. PARTICIPANTS: We included 216 877 patients aged ≥18 years, undergoing non-cardiac surgery, not exposed to opioids 180 days before and alive 12 months after surgery. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary endpoint was collection of at least three opioid prescriptions during the first postoperative year; within 90 days, day 91-180 and 181-365 after surgery in a previously opioid-naïve patient. Second, multivariable logistic regression analysis was conducted to explore potential risk factors associated with prolonged opioid use. RESULTS: Of the 216 877 patients identified to undergo analysis, 15 081 (7.0%) developed new prolonged opioid consumption. Several risk factors were identified. Having a history of psychiatric disease was identified as the strongest risk factor (adjusted odds ratio: 1.94; 95% CI: 1.87 to 2.00). CONCLUSION: In a large Swedish cohort of surgical patients, 7% developed new prolonged opioid consumption after major surgery. Our data on susceptible patients could help clinicians reduce the number of prolonged opioid users by adapting their analgesic and preventative strategies.

Postoperative complications and myocardial injury in patients receiving air or oxygen. Prospective, randomised and pilot study.

BACKGROUND: Supplementary oxygen is administered during anaesthesia to increase oxygen delivery and prevent hypoxia. Recent studies have questioned this routine. In this pilot study, our main aim was to investigate if 21% oxygen compared to ≥50% reduces the risk of postoperative complications and myocardial injury. METHODS: In this pragmatic, multicentre, single-blind study, patients undergoing vascular surgery were randomised to receive a fraction of inspired oxygen (Fi O2 ) ≥ 0.50 and oxygen saturation determined by pulse oximetry (SpO2 ) ≥ 98% (group H) or Fi O2 of 0.21 and SpO2 > 90% (group N) oxygen perioperatively. The primary outcome was a composite outcome of major pre-defined postoperative complications assessed at 30 days. Myocardial injury was determined by serial troponin measurements. Data were analysed using generalised estimating equation, Mann-Whitney U test or chi-squared test, as appropriate. RESULTS: The 191 patients were randomised, and per-protocol principle was used for analyses. At 30-day follow-up, 43 out of 94 patients (46%) had a postoperative complication in group H and 36 out of 90 patients (40%) in group N, p = .46. New myocardial injury was seen in 27% versus 22% in Groups H and N respectively (p = .41). No differences in other outcomes were observed between the groups. Twelve patients (13%) in Group N had SpO2 < 90%, six recovered spontaneously and six required supplemental oxygen. At 1-year follow-up, one patient in group H had died. CONCLUSION: In this pilot study, postoperative complications were similar between the groups in patients randomised to Fi O2 of 0.21 or ≥0.50 and no difference was found in the incidence of new myocardial injury. Larger, prospective adequately powered studies are needed.

Predicting peri-operative troponin elevation by advanced electrocardiography.

BACKGROUND: Peri-operative mortality remains a global problem and an improved pre-operative risk assessment identifying those at highest risk for peri-operative myocardial injury might improve postsurgical outcomes. AIMS: To determine whether pre-operative measures of advanced electrocardiography (A-ECG) could predict elevated serum troponin T (TnT) in patients undergoing elective, major non-cardiac surgery. MATERIAL AND METHODS: This observational cohort study included 257 surgical patients who underwent elective major non-cardiac surgery between the years 2012-2013 and 2015-2016 at Karolinska University Hospital. All selected patients were ≥ 18 years of age [median age 70 (63-75) years], had a pre-operative digital 12­lead ECG < 6 months prior to the procedure and a postoperative high-sensitivity cardiac TnT (hs-cTnT) sample. A-ECG confounders including atrial fibrillation or flutter, abundant premature atrial or ventricular contractions, bundle branch blocks, QRS duration >110 ms, heart rate > 100 beats/min and paced rhythms were excluded. Previously validated A-ECG diagnostic scores that detect cardiovascular pathologies were calculated and compared in patients with and without peri-operative myocardial injury, defined as hs-cTnT >14 ng l-1. RESULTS: Pre-operative left ventricular systolic dysfunction by A-ECG was more probable in patients with than without peri-operative myocardial injury (p = 0.03). CONCLUSIONS: While a pre-operative A-ECG score for LVSD was able to differentiate between patients with versus without elevated peri-operative TnT levels, it did not add any further utility to standard clinical parameters for predicting troponin-related events in the studied population.

Intraoperative Hypotension and Myocardial Infarction Development Among High-Risk Patients Undergoing Noncardiac Surgery: A Nested Case-Control Study.

BACKGROUND: Hemodynamic instability during anesthesia and surgery is common and associated with cardiac morbidity and mortality. Information is needed regarding optimal blood pressure (BP) threshold in the perioperative period. Therefore, the effect of intraoperative hypotension (IOH) on risk of perioperative myocardial infarction (MI) was explored. METHODS: A nested case-control study with patients developing MI <30 days postsurgery matched with non-MI patients, sampled from a large surgery cohort. Study participants were adults undergoing noncardiac surgery at 3 university hospitals in Sweden, 2007-2014. Matching criteria were age, sex, American Society of Anesthesiologists (ASA) physical status, cardiovascular disease, hospital, year-, type-, and extent of surgery. Medical records were reviewed to validate MI diagnoses and retrieve information on comorbid history, baseline BP, laboratory and intraoperative data. Main exposure was IOH, defined as a decrease in systolic blood pressure (SBP), in mm Hg, from preoperative individual resting baseline lasting at least 5 minutes. Outcomes were acute MI, fulfilling the universal criteria, subclassified as type 1 and 2, occurring within 30 days and mortality beyond 30 days among case and control patients. Conditional logistic regression assessed the association between IOH, decrease in SBP from individual baseline, and perioperative MI. Mortality rates were estimated using Cox proportional hazards. Relative risk estimates are reported as are the corresponding absolute risks derived from the well-characterized source population. RESULTS: A total of 326 cases met the inclusion criteria and were successfully matched with 326 controls. The distribution of MI type was 59 (18%) type 1 and 267 (82%) type 2. Median time to MI diagnosis was 2 days; 75% were detected within a week of surgery. Multivariable analysis acknowledged IOH as an independent risk factor of perioperative MI. IOH, with reduction of 41-50 mm Hg, from individual baseline SBP, was associated with a more than tripled increased odds, odds ratio (OR) = 3.42 (95% confidence interval [CI], 1.13-10.3), and a hypotensive event >50 mm Hg with considerably increased odds in respect to MI risk, OR = 22.6, (95% CI, 7.69-66.2). In patients with a very high-risk burden, the absolute risk of an MI diagnosis increased from 3.6 to 68 per 1000 surgeries. CONCLUSIONS: In patients undergoing noncardiac surgery, IOH is a possible contributor to clinically significant perioperative MI. The high absolute MI risk associated with IOH, among a growing population of patients with a high-risk burden, suggests that increased vigilance of BP control in these patients may be beneficial.

Heart Failure in Patients Undergoing Elective and Emergency Noncardiac Surgery: Still a Poorly Addressed Risk Factor.

BACKGROUND: Noncardiac surgery is increasingly offered to an older, more comorbid population. The aim was to characterize patients with the diagnosis of heart failure (HF) undergoing elective and emergency noncardiac surgery in a broad, contemporary Swedish cohort, and to assess the short- and long-term mortality in patients with HF as compared with patients without HF. METHODS AND RESULTS: Data from 200,638 and 97,129 patients undergoing elective and emergency surgical procedures at 23 Swedish university, county, and district hospitals during 2007 to 2013 were analyzed through linkage of the surgical Orbit Database to the National Patient and the Cause of Death registries. In total 7212 patients (3.6%) with a diagnosis of HF before surgery underwent elective and 6455 patients (6.6%) underwent emergency surgery. Patients with HF were older had more comorbidities, and higher mortality than patients without HF. Crude and adjusted risk ratios for 30-day mortality after elective surgery were 5.36 (95% confidence interval [CI] 4.67-6.16) and 1.79 (95% CI 1.50-2.14) (adjusted for comorbidities, surgical risk level, age, and sex). Corresponding data for emergency surgery was 3.84 (95% CI 3.58-4.12) and 1.48 (95% CI 1.31-1.62). Mortality in patients with HF after elective surgery at 30 days, 90 days, and 1 year was 3.2%, 6.5%, and 16.2% and after emergency surgery it was 13.7%, 22.4%, and 39.3%. CONCLUSIONS: Patients with HF undergoing elective or emergency noncardiac surgery in a modern surgical setting have a substantial mortality risk and HF is both a risk factor and a strong marker for increasd risk. The reasons for the high mortality are not well-understood and warrant further attention.

Myocardial infarction after noncardiac surgery in Sweden: a national, retrospective observational cohort study.

BACKGROUND: The precise incidence of perioperative myocardial infarction (MI) after noncardiac surgery remains unclear. We determined the incidence and risk factors for perioperative MI after noncardiac surgery and the risk of MI and mortality compared with matched non-surgical patients. METHODS: Patients >18 yr undergoing noncardiac surgery in 23 Swedish hospitals from 2007 to 2014 were included in this national observational retrospective cohort study. We combined national surgical and outcome databases with Swedeheart, a national quality registry capturing data from patients with acute MI. The primary outcome was incidence of MI within 30 days of surgery. Multivariable logistic regression identified preoperative risk factors associated with MI, including ASA grade, diabetes mellitus, and cardiovascular pathology including previous MI. Standardised incidence rate ratios were calculated. Mortality rates were estimated using Cox proportional hazards. RESULTS: A total of 1605/400 742 (0.41%) patients (median age: 64 [49-75] yr) had an MI after surgery, which was independently associated with increasing age, comorbidities and higher risk (vascular, thoracic), emergency surgery, or all. The incidence of perioperative MI (per 1000 surgeries) varied from 0.064 (95% confidence interval [CI], 0.02-012) in low-risk patients (ASA physical status 1) to 15.8 (95% CI, 14.9-16.8) among higher risk patients (ASA physical status ≥3, age ≥80 yr, high-risk surgery). Perioperative MI was associated with higher 30-day mortality (adjusted odds ratio: 5.49 [95% 4.76-6.32]). Compared with the non-surgical Swedish population, the perioperative standardised incidence rate ratio was five-fold higher (odds ratio: 5.35 [95% CI: 5.09-5.61]). CONCLUSIONS: In a large Swedish surgical cohort, the incidence of MI within 30 days of noncardiac surgery was 0.41%, chiefly occurring in a small subset of higher risk patients.

Opioid Prescribing After Surgery in the United States, Canada, and Sweden.

Importance: Small studies and anecdotal evidence suggest marked differences in the use of opioids after surgery internationally; however, this has not been evaluated systematically across populations receiving similar procedures in different countries. Objective: To determine whether there are differences in the frequency, amount, and type of opioids dispensed after surgery among the United States, Canada, and Sweden. Design, Setting, and Participants: This cohort study included patients without previous opioid prescriptions aged 16 to 64 years who underwent 4 low-risk surgical procedures (ie, laparoscopic cholecystectomy, laparoscopic appendectomy, arthroscopic knee meniscectomy, and breast excision) between January 2013 and December 2015 in the United States, between July 2013 and March 2016 in Canada, and between January 2013 and December 2014 in Sweden. Data analysis was conducted in all 3 countries from July 2018 to October 2018. Main Outcomes and Measures: The main outcome was postoperative opioid prescriptions filled within 7 days after discharge; the percentage of patients who filled a prescription, the total morphine milligram equivalent (MME) dose, and type of opioid dispensed were compared. Results: The study sample consisted of 129 379 patients in the United States, 84 653 in Canada, and 9802 in Sweden. Overall, 52 427 patients (40.5%) in the United States were men, with a mean (SD) age of 45.1 (12.7) years; in Canada, 25 074 patients (29.6%) were men, with a mean (SD) age of 43.5 (13.0) years; and in Sweden, 3314 (33.8%) were men, with a mean (SD) age of 42.5 (13.0). The proportion of patients in Sweden who filled an opioid prescription within the first 7 days after discharge for any procedure was lower than patients treated in the United States and Canada (Sweden, 1086 [11.1%]; United States, 98 594 [76.2%]; Canada, 66 544 [78.6%]; P < .001). For patients who filled a prescription, the mean (SD) MME dispensed within 7 days of discharge was highest in United States (247 [145] MME vs 169 [93] MME in Canada and 197 [191] MME in Sweden). Codeine and tramadol were more commonly dispensed in Canada (codeine, 26 136 patients [39.3%]; tramadol, 12 285 patients [18.5%]) and Sweden (codeine, 170 patients [15.7%]; tramadol, 315 patients [29.0%]) than in the United States (codeine, 3210 patients [3.3%]; tramadol, 3425 patients [3.5%]). Conclusions and Relevance: The findings indicate that the United States and Canada have a 7-fold higher rate of opioid prescriptions filled in the immediate postoperative period compared with Sweden. Of the 3 countries examined, the mean dose of opioids for most surgical procedures was highest in the United States.

Days at Home after Surgery: An Integrated and Efficient Outcome Measure for Clinical Trials and Quality Assurance.

BACKGROUND: Surgical audit, sometimes including public reporting, is an important foundation of high quality health care. We aimed to assess the validity of a novel outcome metric, days at home up to 30 days after surgery, as a surgical outcome measure in clinical trials and quality assurance. METHODS: This was a multicentre, registry-based cohort study. We used prospectively collected hospital and national healthcare registry data obtained from patients aged 18 years or older undergoing a broad range of surgeries in Sweden over a 10-year period. The association between days at home up to 30 days after surgery and patient (older age, poorer physical status, comorbidity) and surgical (elective or non-elective, complexity, duration) risk factors, process of care outcomes (re-admissions, discharge destination), clinical outcomes (major complications, 30-day mortality) and death up to 1 year after surgery were measured. FINDINGS: From January, 2005, to December, 2014, we obtained demographic and perioperative data on 636,885 patients from 21 Swedish hospitals. Mortality at 30 days and one year was 1.8% and 7.3%, respectively. The median (IQR) days at home up to 30 days after surgery was 27 (23-29), being significantly lower among high-risk patients, those recovering from more complex surgical procedures, and suffering serious postoperative complications (all p < 0.0001). Patients with 8 days or less at home up to 30 days after surgery had a nearly 7-fold higher risk of death up to 1 year postoperatively when compared with those with 29 or 30 days at home (adjusted HR 6.78 [95% CI: 6.44-7.13]). INTERPRETATION: Days at home up to 30 days after surgery is a valid, easy to measure patient-centred outcome metric. It is highly sensitive to changes in surgical risk and impact of complications, and has prognostic importance; it is therefore a valuable endpoint for perioperative clinical trials and quality assurance. FUNDING: Swedish National Research Council Medicine and Stockholm County Council ALF-project grant (LE), and the Australian National Health and Medical Research Council (PM).

Intraoperative hypotension is associated with acute kidney injury in noncardiac surgery: An observational study.

BACKGROUND: Perioperative acute kidney injury (AKI) is common and increases the risk of morbidity and mortality. OBJECTIVES: To determine the association between intraoperative hypotension, defined as an individual decrease from baseline and the risk of perioperative AKI. DESIGN: Observational cohort study. SETTING: Karolinska University Hospital, Stockholm, Sweden, from October 2012 to May 2013 and October 2015 and April 2016. PATIENTS: All adult patients undergoing major elective noncardiac surgery who were scheduled for an overnight admission in the postoperative unit were included. Patients undergoing phaeochromocytoma surgery were excluded. DATA COLLECTION: Preoperative risk factors (comorbidities), intraoperative events (hypotension defined as a more than 40 or 50% decrease in SBP relative to each patient's baseline and lasting more than 5 min) and postoperative data were collected from medical records. MAIN OUTCOME MEASURES: AKI within the first two postoperative days. RESULTS: Of the final cohort of 470 patients, 127 (27%) developed AKI in the perioperative period. AKI was associated with male sex [(66 vs. 48%) P < 0.001], a higher preoperative creatinine (81 vs. 73 µmol l, P = 0.003), American Society of Anaesthesiologists class more than two (54 vs. 42%, P = 0.014) and preoperative hypertension (54 vs. 40%, P = 0.005). During surgery, the AKI subgroup had more hypotensive events (>40%, 70 vs. 57%, P = 0.013; >50%, 20 vs. 12%, P = 0.024) and greater blood loss (800 vs. 400 ml, P < 0.001). Postoperatively, in AKI patients a positive fluid balance was more common (3123 vs. 2700 ml, P < 0.001), as was 30-day mortality (4 vs. 1%, P < 0.005). Multivariate analyses demonstrated that an intraoperative reduction of SBP more than 50% was associated with a more than doubled risk of AKI, adjusted odds ratio 2.27; 95% CI, 1.20 to 4.30, P = 0.013. CONCLUSION: In patients undergoing noncardiac surgery, there was a high incidence of perioperative AKI. Intraoperative avoidance of hypotension may decrease the risk of AKI.

Intraoperative hypotension is associated with myocardial damage in noncardiac surgery: An observational study.

BACKGROUND: Perioperative myocardial damage and infarction (MI) is associated with increased mortality and other postoperative complications. OBJECTIVES: To assess the incidence of perioperative myocardial damage in patients undergoing major elective noncardiac surgery, to elucidate any association with postoperative MI and mortality and to estimate the impact of preoperative risk factors and intraoperative hypotension. DESIGN: Observational cohort study. SETTING: Karolinska University Hospital, Stockholm, Sweden, from October 2012 to May 2013. PATIENTS: In this single-centre study, all adult patients undergoing major elective noncardiac surgery who were scheduled for an overnight admission to the postoperative unit were included. Patients undergoing phaeochromocytoma surgery were excluded. Preoperative risk factors (co-morbidities), intraoperative events (hypotension defined as a 50% decrease in SBP relative to each patient's baseline and lasting >5 min) and postoperative data were collected from medical records. Levels of high-sensitivity cardiac troponin T (hs-cTnT) were measured on postoperative day 1. Myocardial damage was defined as an increase in the hs-cTnT value above 14 ng l. A cardiologist reviewed all cases of MI occurring within 30 days after surgery. MAIN OUTCOME MEASURES: Myocardial damage, MI and mortality within 30 days after surgery. RESULTS: Of the final cohort of 300 patients, 90 (30%) had myocardial damage on postoperative day 1 and 15 (5%) developed postoperative MI within 30 days. Multivariate logistic regression analysis demonstrated that an intraoperative reduction in SBP more than 50% from baseline lasting more than 5 min was an independent predictor of postoperative hs-cTnT elevation (odds ratio, 4.4; 95% confidence interval, 1.8 to 11.1). CONCLUSIONS: In a cohort of 300 patients undergoing major elective noncardiac surgery, there was a high incidence of myocardial damage and an association between an intraoperative reduction in SBP more than 50% from baseline lasting more than 5 min and myocardial damage.