Preoperative systemic inflammation and perioperative myocardial injury: prospective observational multicentre cohort study of patients undergoing non-cardiac surgery.

BACKGROUND: Systemic inflammation is pivotal in the pathogenesis of cardiovascular disease. As inflammation can directly cause cardiomyocyte injury, we hypothesised that established systemic inflammation, as reflected by elevated preoperative neutrophil-lymphocyte ratio (NLR) >4, predisposes patients to perioperative myocardial injury. METHODS: We prospectively recruited 1652 patients aged ≥45 yr who underwent non-cardiac surgery in two UK centres. Serum high sensitivity troponin T (hsTnT) concentrations were measured on the first three postoperative days. Clinicians and investigators were blinded to the troponin results. The primary outcome was perioperative myocardial injury, defined as hsTnT≥14 ng L-1 within 3 days after surgery. We assessed whether myocardial injury was associated with preoperative NLR>4, activated reactive oxygen species (ROS) generation in circulating monocytes, or both. Multivariable logistic regression analysis explored associations between age, sex, NLR, Revised Cardiac Risk Index, individual leukocyte subsets, and myocardial injury. Flow cytometric quantification of ROS was done in 21 patients. Data are presented as n (%) or odds ratio (OR) with 95% confidence intervals. RESULTS: Preoperative NLR>4 was present in 239/1652 (14.5%) patients. Myocardial injury occurred in 405/1652 (24.5%) patients and was more common in patients with preoperative NLR>4 [OR: 2.56 (1.92-3.41); P<0.0001]. Myocardial injury was independently associated with lower absolute preoperative lymphocyte count [OR 1.80 (1.50-2.17); P<0.0001] and higher absolute preoperative monocyte count [OR 1.93 (1.12-3.30); P=0.017]. Monocyte ROS generation correlated with NLR (r=0.47; P=0.03). CONCLUSIONS: Preoperative NLR>4 is associated with perioperative myocardial injury, independent of conventional risk factors. Systemic inflammation may contribute to the development of perioperative myocardial injury. CLINICAL TRIAL REGISTRATION: NCT01842568.

Association between preoperative pulse pressure and perioperative myocardial injury: an international observational cohort study of patients undergoing non-cardiac surgery.

BACKGROUND: The management of elevated blood pressure before non-cardiac surgery remains controversial. Pulse pressure is a stronger predictor of cardiovascular morbidity in the general population than systolic blood pressure alone. We hypothesized that preoperative pulse pressure was associated with perioperative myocardial injury. METHODS: This is a secondary analysis of the Vascular Events in Non-cardiac Surgery Patients Cohort Evaluation (VISION) international cohort study. Participants were aged ≥45 yr and undergoing non-cardiac surgery at 12 hospitals in eight countries. The primary outcome was myocardial injury, defined using serum troponin concentration, within 30 days after surgery. The sample was stratified into quintiles by preoperative pulse pressure. Multivariable logistic regression analysis explored associations between pulse pressure and myocardial injury. We accounted for potential confounding by systolic blood pressure and other co-morbidities known to be associated with postoperative cardiovascular complications. RESULTS: One thousand one hundred and ninety-one of 15 057 (7.9%) patients sustained myocardial injury, which was more frequent amongst patients in the highest two preoperative pulse pressure quintiles {63-75 mm Hg, risk ratio (RR) 1.14 [95% confidence interval (CI): 1.01-1.28], P =0.03; >75 mm Hg, RR 1.15 [95% CI: 1.03-1.29], P =0.02}. After adjustment for systolic blood pressure, preoperative pulse pressure remained the dominant predictor of myocardial injury (63-75 mm Hg, RR 1.20 [95% CI: 1.05-1.37], P <0.01; >75 mm Hg, RR 1.25 [95% CI: 1.06-1.48], P <0.01). Systolic blood pressure >160 mm Hg was not associated with myocardial injury in the absence of pulse pressure >62 mm Hg (RR 0.67 [95% CI: 0.30-1.44], P =0.31). CONCLUSIONS: Preoperative pulse pressure >62 mm Hg was associated with myocardial injury, independent of systolic blood pressure. Elevated pulse pressure may be a useful clinical sign to guide strategies to reduce perioperative myocardial injury.

Preoperative heart rate and myocardial injury after non-cardiac surgery: results of a predefined secondary analysis of the VISION study.

BACKGROUND: Increased baseline heart rate is associated with cardiovascular risk and all-cause mortality in the general population. We hypothesized that elevated preoperative heart rate increases the risk of myocardial injury after non-cardiac surgery (MINS). METHODS: We performed a secondary analysis of a prospective international cohort study of patients aged ≥45 yr undergoing non-cardiac surgery. Preoperative heart rate was defined as the last measurement before induction of anaesthesia. The sample was divided into deciles by heart rate. Multivariable logistic regression models were used to determine relationships between preoperative heart rate and MINS (determined by serum troponin concentration), myocardial infarction (MI), and death within 30 days of surgery. Separate models were used to test the relationship between these outcomes and predefined binary heart rate thresholds. RESULTS: Patients with missing outcomes or heart rate data were excluded from respective analyses. Of 15 087 patients, 1197 (7.9%) sustained MINS, 454 of 16 007 patients (2.8%) sustained MI, and 315 of 16 037 patients (2.0%) died. The highest heart rate decile (>96 beats min(-1)) was independently associated with MINS {odds ratio (OR) 1.48 [1.23-1.77]; P<0.01}, MI (OR 1.71 [1.34-2.18]; P<0.01), and mortality (OR 3.16 [2.45-4.07]; P<0.01). The lowest decile (<60 beats min(-1)) was independently associated with reduced mortality (OR 0.50 [0.29-0.88]; P=0.02), but not MINS or MI. The predefined binary thresholds were also associated with MINS, but more weakly than the highest heart rate decile. CONCLUSIONS: Preoperative heart rate >96 beats min(-1) is associated with MINS, MI, and mortality after non-cardiac surgery. This association persists after accounting for potential confounding factors. CLINICAL TRIAL REGISTRATION: NCT00512109.