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.

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.

Comparison of high-sensitivity cardiac troponin I and T for the prediction of cardiac complications after non-cardiac surgery.

BACKGROUND: We aimed to directly compare preoperative high-sensitivity cardiac troponin (hs-cTn) I and T concentration for the prediction of major cardiac complications after non-cardiac surgery. METHODS: We measured hs-cTnI and hs-cTnT preoperatively in a blinded fashion in 1022 patients undergoing non-cardiac surgery. The primary endpoint was a composite of major cardiac complications including cardiac death, cardiac arrest, myocardial infarction, clinically relevant arrhythmias, and acute heart failure within 30 days. We hypothesized that the type of surgery may impact on the predictive accuracy of hs-cTnI/T and stratified all analyses according to the type of surgery. RESULTS: Major cardiac complications occurred in 108 (11%) patients, 58/243 (24%) patients undergoing vascular surgery and 50/779 (6%, P < .001) patients undergoing non-vascular surgery. Using regulatory-approved 99th percentile cut-off concentrations, preoperative hs-cTnI elevations were less than one-fifth as common as preoperative hs-cTnT elevations (P < .001). Among patients undergoing vascular surgery, preoperative hs-cTnI concentrations, but not hs-cTnT, was an independent predictor of cardiac complications (adjusted odds ratio (aOR) 1.5, 95% confidence interval (95% CI) 1.0-2.1). The area under the receiver-operating characteristics curve (AUC) was 0.67 (95% CI, 0.59-0.75) for hs-cTnI versus 0.59 (95% CI 0.51-0.67, P = .012) for hs-cTnT. In contrast, among patients undergoing non-vascular surgery both preoperative hs-cTnI and hs-cTnT were independent predictors of the primary endpoint (aOR 1.6, 95% CI 1.3-2.0, and aOR 3.0, 95% CI 2.0-4.6, respectively) and showed higher predictive accuracy (AUC 0.77, 95% CI, 0.71-0.83, and 0.79, 95% CI 0.73-0.85, P = ns). CONCLUSIONS: Preoperative hs-cTnI and hs-cTnT concentrations predict major cardiac complications after non-vascular surgery, while, in patients undergoing vascular surgery, hs-cTnI may have better accuracy.

Automatically computed ECG algorithm for the quantification of myocardial scar and the prediction of mortality.

BACKGROUND: Myocardial scar is associated with adverse cardiac outcomes. The Selvester QRS-score was developed to estimate myocardial scar from the 12-lead ECG, but its manual calculation is difficult. An automatically computed QRS-score would allow identification of patients with myocardial scar and an increased risk of mortality. OBJECTIVES: To assess the diagnostic and prognostic value of the automatically computed QRS-score. METHODS: The diagnostic value of the QRS-score computed automatically from a standard digital 12-lead was prospectively assessed in 2742 patients with suspected myocardial ischemia referred for myocardial perfusion imaging (MPI). The prognostic value of the QRS-score was then prospectively tested in 1151 consecutive patients presenting to the emergency department (ED) with suspected acute heart failure (AHF). RESULTS: Overall, the QRS-score was significantly higher in patients with more extensive myocardial scar: the median QRS-score was 3 (IQR 2-5), 4 (IQR 2-6), and 7 (IQR 4-10) for patients with 0, 5-20 and > 20% myocardial scar as quantified by MPI (p < 0.001 for all pairwise comparisons). A QRS-score ≥ 9 (n = 284, 10%) predicted a large scar defined as > 20% of the LV with a specificity of 91% (95% CI 90-92%). Regarding clinical outcomes in patients presenting to the ED with symptoms suggestive of AHF, mortality after 1 year was 28% in patients with a QRS-score ≥ 3 as opposed to 20% in patients with a QRS-score < 3 (p = 0.001). CONCLUSIONS: The QRS-score can be computed automatically from the 12-lead ECG for simple, non-invasive and inexpensive detection and quantification of myocardial scar and for the prediction of mortality. TRIAL-REGISTRATION: http://www.clinicaltrials.gov . Identifier, NCT01838148 and NCT01831115.

Perioperative Myocardial Injury After Noncardiac Surgery: Incidence, Mortality, and Characterization.

BACKGROUND: Perioperative myocardial injury (PMI) seems to be a contributor to mortality after noncardiac surgery. Because the vast majority of PMIs are asymptomatic, PMI usually is missed in the absence of systematic screening. METHODS: We performed a prospective diagnostic study enrolling consecutive patients undergoing noncardiac surgery who had a planned postoperative stay of ≥24 hours and were considered at increased cardiovascular risk. All patients received a systematic screening using serial measurements of high-sensitivity cardiac troponin T in clinical routine. PMI was defined as an absolute high-sensitivity cardiac troponin T increase of ≥14 ng/L from preoperative to postoperative measurements. Furthermore, mortality was compared among patients with PMI not fulfilling additional criteria (ischemic symptoms, new ECG changes, or imaging evidence of loss of viable myocardium) required for the diagnosis of spontaneous acute myocardial infarction versus those that did. RESULTS: From 2014 to 2015 we included 2018 consecutive patients undergoing 2546 surgeries. Patients had a median age of 74 years and 42% were women. PMI occurred after 397 of 2546 surgeries (16%; 95% confidence interval, 14%-17%) and was accompanied by typical chest pain in 24 of 397 patients (6%) and any ischemic symptoms in 72 of 397 (18%). Crude 30-day mortality was 8.9% (95% confidence interval [CI], 5.7-12.0) in patients with PMI versus 1.5% (95% CI, 0.9-2.0) in patients without PMI (P<0.001). Multivariable regression analysis showed an adjusted hazard ratio of 2.7 (95% CI, 1.5-4.8) for 30-day mortality. The difference was retained at 1 year with mortality rates of 22.5% (95% CI, 17.6-27.4) versus 9.3% (95% CI, 7.9-10.7). Thirty-day mortality was comparable among patients with PMI not fulfilling any other of the additional criteria required for spontaneous acute myocardial infarction (280/397, 71%) versus those with at least 1 additional criterion (10.4%; 95% CI, 6.7-15.7, versus 8.7%; 95% CI, 4.2-16.7; P=0.684). CONCLUSIONS: PMI is a common complication after noncardiac surgery and, despite early detection during routine clinical screening, is associated with substantial short- and long-term mortality. Mortality seems comparable in patients with PMI not fulfilling any other of the additional criteria required for spontaneous acute myocardial infarction versus those patients who do. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02573532.

Combining high-sensitivity cardiac troponin and B-type natriuretic peptide in the detection of inducible myocardial ischemia.

BACKGROUND: Single biomarker approaches provide only moderate accuracy in the non-invasive detection of exercise-induced myocardial ischemia. We therefore assessed the combination of the two most promising single biomarkers: high-sensitivity cardiac troponin I (hs-cTnI) and B-type natriuretic peptide (BNP). METHODS: Consecutive patients with suspected myocardial ischemia referred to stress myocardial perfusion single-photon emission tomography imaging (MPI) were enrolled. Clinical judgment (CJ) of the treating cardiologist regarding myocardial ischemia, quantified using a visual analogue scale, and blood concentrations of hs-cTnI and BNP were determined before and after stress. The presence of myocardial ischemia was adjudicated by independent cardiologists using MPI, blinded to biomarker measurements. Death and acute myocardial infarction (AMI) during follow-up were the prognostic endpoints. RESULTS: Among 1142 consecutive patients inducible myocardial ischemia was found in 456 (40%) of all patients. For the detection of inducible myocardial ischemia, CJ before exercise stress testing (CJb) showed an area under the receiver-operating-characteristics curve (AUC) of 0.66 (95%CI 0.63-0.69), hs-cTnI 0.70 (95%CI 0.67-0.73, p=0.07 vs CJb), and BNP 0.66 (95%CI 0.62-0.69, p=0.98). The use of a dual-biomarker strategy combining hs-cTnI and BNP with CJb did not provide a significant advantage over the combination of hs-cTnI alone and CJb (AUC 0.74, 95%CI 0.72-0.77 vs AUC 0.74, 95%CI 0.71-0.77, p=0.16). Hs-cTnI showed good prognostic value for AMI (HR 1.6, 95%CI 1.3-1.9), and BNP for death (HR 1.6, 95%CI 1.3-2.1). CONCLUSION: A dual-biomarker strategy combing BNP and hs-cTnI does not further increase diagnostic accuracy on top of clinical judgment and hs-cTnI alone. SUMMARY AND HIGHLIGHTS: We included 1142 consecutive patients with suspected inducible ischemia, and evaluated the added value of the biomarkers high-sensitivity cardiac troponin (hs-cTn) and B-type natriuretic peptide (BNP), alone and in combination, on top of clinical judgment. CLINICAL TRIAL REGISTRATION: Biochemical and Electrocardiographic Signatures in the Detection of Exercise-induced Myocardial Ischemia (BASEL VIII), NCT01838148, https://clinicaltrials.gov/ct2/show/NCT01838148.

Prospective Validation of a Biomarker-Based Rule Out Strategy for Functionally Relevant Coronary Artery Disease.

BACKGROUND: This study aimed to prospectively advance a rule-out strategy for functionally significant coronary artery disease (CAD) by use of high-sensitivity cardiac troponin I (hs-cTnI) from bench to bedside, by application of a 3-step approach: validation in serum, correlation in plasma, and application on a clinical platform. METHODS: Patients without known CAD referred for rest/stress myocardial perfusion single-photon emission tomography/computer tomography (MPI-SPECT/CT) were assigned to 3 consecutive cohorts: validation, correlation, and application. Functionally relevant CAD was adjudicated with the use of expert interpretation of MPI-SPECT/CT and, if available, coronary angiography. In the validation cohort resting hs-cTnI was measured in serum before stress testing with the research Erenna system, in serum and plasma in the correlation cohort with the research Erenna system, and in plasma in the application cohort with the clinical Clarity system. RESULTS: Overall, functionally relevant CAD was adjudicated in 21% (304/1478) of patients. In the validation cohort (n = 613), hs-cTnI concentrations were significantly higher in patients with functionally relevant CAD (median 2.8 ng/L vs 1.9 ng/L, P < 0.001) as compared to patients without functionally relevant CAD and allowed a rule out with 95% sensitivity in 14% of patients. In the correlation cohort (n = 606), hs-cTnI concentrations in serum and plasma strongly correlated (Spearman r = 0.921) and had similar diagnostic accuracy as quantified by the area under the receiver operating characteristic curve (0.686 vs 0.678, P = 0.425). In the application cohort (n = 555), very low hs-cTnI plasma concentrations (< 0.5 ng/L) ruled out functionally relevant CAD with 95% sensitivity in 10% of patients. CONCLUSIONS: A single resting plasma hs-cTnI measurement can safely rule out functionally relevant CAD in around 10% of patients without known CAD.