Patient- and procedure-related factors in the pathophysiology of perioperative myocardial infarction/injury.

BACKGROUND: Perioperative myocardial infarction/injury (PMI) is a frequent, often missed and incompletely understood complication of noncardiac surgery. The aim of this study was to evaluate whether patient- or procedure-related factors are more strongly associated to the development of PMI in patients undergoing repeated noncardiac surgery. METHODS: In this prospective observational study, patient- and procedure-related factors were evaluated for contribution to PMI using: 1) logistic regression modelling with PMI as primary endpoint, 2) evaluation of concordance of PMI occurrence in the first and the second noncardiac surgery (surgery 1 and 2). and 3) the correlation of the extent of cardiomyocyte injury quantified by high-sensitivity cardiac troponin T between surgery 1 and 2. The secondary endpoint was all-cause mortality associated with PMI reoccurrence in surgery 2. RESULTS: Among 784 patients undergoing repeated noncardiac surgery (in total 1'923 surgical procedures), 116 patients (14.8%) experienced PMI during surgery 1. Among these, PMI occurred again in surgery 2 in 35/116 (30.2%) patients. However, the vast majority of patients developing PMI during surgery 2 (96/131, 73.3%) had not developed PMI during surgery 1 (phi-coefficient 0.150, p < 0.001). The correlation between the extent of cardiomyocyte injury occurring during surgery 1 and 2 was 0.153. All-cause mortality following a second PMI in surgery 2 was dependent on time since surgery (adjusted hazard ratio 5.6 within 30 days and 2.4 within 360 days). CONCLUSIONS: In high-risk patients, procedural factors are more strongly associated with occurrence of PMI than patient factors, but patient factors are also contributors to the occurrence of PMI.

Incidence and outcomes of perioperative myocardial infarction/injury diagnosed by high-sensitivity cardiac troponin I.

BACKGROUND:  Perioperative myocardial infarction/injury (PMI) diagnosed by high-sensitivity troponin (hs-cTn) T is frequent and a prognostically important complication of non-cardiac surgery. We aimed to evaluate the incidence and outcome of PMI diagnosed using hs-cTnI, and compare it to PMI diagnosed using hs-cTnT. METHODS: We prospectively included 2455 patients at high cardiovascular risk undergoing 3111 non-cardiac surgeries, for whom hs-cTnI and hs-cTnT concentrations were measured before surgery and on postoperative days 1 and 2. PMI was defined as a composite of perioperative myocardial infarction (PMIInfarct) and perioperative myocardial injury (PMIInjury), according to the Fourth Universal Definition of Myocardial Infarction. All-cause mortality was the primary endpoint. RESULTS: Using hs-cTnI, the incidence of overall PMI was 9% (95% confidence interval [CI] 8-10%), including PMIInfarct 2.6% (95% CI 2.0-3.2) and PMIInjury 6.1% (95% CI 5.3-6.9%), which was lower versus using hs-cTnT: overall PMI 15% (95% CI 14-16%), PMIInfarct 3.7% (95% CI 3.0-4.4) and PMIInjury 11.3% (95% CI 10.2-12.4%). All-cause mortality occurred in 52 (2%) patients within 30 days and 217 (9%) within 1 year. Using hs-cTnI, both PMIInfarct and PMIInjury were independent predictors of 30-day all-cause mortality (adjusted hazard ratio [aHR] 2.5 [95% CI 1.1-6.0], and aHR 2.8 [95% CI 1.4-5.5], respectively) and, 1-year all-cause mortality (aHR 2.0 [95% CI 1.2-3.3], and aHR 1.8 [95% CI 1.2-2.7], respectively). Overall, the prognostic impact of PMI diagnosed by hs-cTnI was comparable to the prognostic impact of PMI using hs-cTnT. CONCLUSIONS: Using hs-cTnI, PMI is less common versus using hs-cTnT. Using hs-cTnI, both PMIInfarct and PMIInjury remain independent predictors of 30-day and 1-year mortality.

Incidence of major adverse cardiac events following non-cardiac surgery.

AIMS: Major adverse cardiac events (MACE) triggered by non-cardiac surgery are prognostically important perioperative complications. However, due to often asymptomatic presentation, the incidence and timing of postoperative MACE are incompletely understood. METHODS AND RESULTS: We conducted a prospective observational study implementing a perioperative screening for postoperative MACE [cardiovascular death (CVD), acute heart failure (AHF), haemodynamically relevant arrhythmias, spontaneous myocardial infarction (MI), and perioperative myocardial infarction/injury (PMI)] in patients at increased cardiovascular risk (≥65 years OR ≥45 years with history of cardiovascular disease) undergoing non-cardiac surgery at a tertiary hospital. All patients received serial measurements of cardiac troponin to detect asymptomatic MACE. Among 2265 patients (mean age 73 years, 43.4% women), the incidence of MACE was 15.2% within 30 days, and 20.6% within 365 days. CVD occurred in 1.2% [95% confidence interval (CI) 0.9-1.8] and in 3.7% (95% CI 3.0-4.5), haemodynamically relevant arrhythmias in 1.2% (95% CI 0.9-1.8) and in 2.1% (95% CI 1.6-2.8), AHF in 1.6% (95% CI 1.2-2.2) and in 4.2% (95% CI 3.4-5.1), spontaneous MI in 0.5% (95% CI 0.3-0.9) and in 1.6% (95% CI 1.2-2.2), and PMI in 13.2% (95% CI 11.9-14.7) and in 14.8% (95% CI 13.4-16.4) within 30 days and within 365 days, respectively. The MACE-incidence was increased above presumed baseline rate until Day 135 (95% CI 104-163), indicating a vulnerable period of 3-5 months. CONCLUSION: One out of five high-risk patients undergoing non-cardiac surgery will develop one or more MACE within 365 days. The risk for MACE remains increased for about 5 months after non-cardiac surgery. TRIAL REGISTRATION: https://www.clinicaltrials.gov. Unique identifier: NCT02573532.

Obesity paradox and perioperative myocardial infarction/injury in non-cardiac surgery.

BACKGROUND: The impact of obesity on the incidence of perioperative myocardial infarction/injury (PMI) and mortality following non-cardiac surgery is not well understood. METHODS: We performed a prospective diagnostic study enrolling consecutive patients undergoing non-cardiac surgery, who were considered at increased cardiovascular risk. All patients were screened for PMI, defined as an absolute increase from preoperative to postoperative sensitive/high-sensitivity cardiac troponin T (hs-cTnT) concentrations. The body mass index (BMI) was classified according to the WHO classification (underweight< 18 kg/m2, normal weight 18-24.9 kg/m2, overweight 25-29.9 kg/m2, obesity class I 30-34.9 kg/m2, obesity class II 35-39.9 kg/m2, obesity class III > 40 kg/m2). The incidence of PMI and all-cause mortality at 365 days, both stratified according to BMI. RESULTS: We enrolled 4277 patients who had undergone 5413 surgeries. The median BMI was 26 kg/m2 (interquartile range 23-30 kg/m2). Incidence of PMI showed a non-linear relationship with BMI and ranged from 12% (95% CI 9-14%) in obesity class I to 19% (95% CI 17-42%) in the underweight group. This was confirmed in multivariable analysis with obesity class I. showing the lowest risk (adjusted OR 0.64; 95% CI 0.49-0.83) for developing PMI. Mortality at 365 days was lower in all obesity groups compared to patients with normal body weight (e.g., unadjusted OR 0.54 (95% CI 0.39-0.73) and adjusted OR 0.52 (95% CI 0.38-0.71) in obesity class I). CONCLUSION: Obesity class I was associated with a lower incidence of PMI, and obesity in general was associated with a lower all-cause mortality at 365 days.