METHODS: A dataset containing medical records of 809 patients suspected to suffer from ACS was used. For each subject, 266 clinical factors were collected. At first, a feature selection was performed based on interviews with 20 cardiologists; thereby 40 seminal features for classifying ACS were selected. Next, a feature selection algorithm was also applied to detect a subset of the features with the best classification accuracy. As a result, the feature numbers considerably reduced to only seven. Lastly, based on the seven selected features, eight various common pattern recognition tools for classification of ACS were used.
RESULTS: The performance of the aforementioned classifiers was compared based on their accuracy computed from their confusion matrices. Among these methods, the multi-layer perceptron showed the best performance with the 83.2% accuracy.
CONCLUSION: The results reveal that an integrated AI-based feature selection and classification approach is an effective method for the early and accurate classification of ACS and ultimately a timely diagnosis and treatment of this disease.
Materials and Methods: Age-matched seven male and seven female triathletes were recruited for the study. They were on a standardized training regimen and on average competed in at least one endurance event every month for the past 3-4 years. Serum biomarkers were measured using enzyme-linked immunosorbent assay at the start and at end of the racing season.
Results: Both male and female triathletes showed a statistically significant increase in 8-OHdG. A similar pattern of increase was seen with serum myoglobin, which was not statistically significant in both male and female triathletes. cTnI levels did not show any change in both sexes.
Conclusion: Our study shows that there could be an increased evidence of DNA damage among triathletes. However, similar effects were not observed with skeletal and cardiac muscle biomarkers.
Objective: To determine whether preoperative NT-proBNP has additional predictive value beyond a clinical risk score for the composite of vascular death and myocardial injury after noncardiac surgery (MINS) within 30 days after surgery.
Design: Prospective cohort study.
Setting: 16 hospitals in 9 countries.
Patients: 10 402 patients aged 45 years or older having inpatient noncardiac surgery.
Measurements: All patients had NT-proBNP levels measured before surgery and troponin T levels measured daily for up to 3 days after surgery.
Results: In multivariable analyses, compared with preoperative NT-proBNP values less than 100 pg/mL (the reference group), those of 100 to less than 200 pg/mL, 200 to less than 1500 pg/mL, and 1500 pg/mL or greater were associated with adjusted hazard ratios of 2.27 (95% CI, 1.90 to 2.70), 3.63 (CI, 3.13 to 4.21), and 5.82 (CI, 4.81 to 7.05) and corresponding incidences of the primary outcome of 12.3% (226 of 1843), 20.8% (542 of 2608), and 37.5% (223 of 595), respectively. Adding NT-proBNP thresholds to clinical stratification (that is, the Revised Cardiac Risk Index [RCRI]) resulted in a net absolute reclassification improvement of 258 per 1000 patients. Preoperative NT-proBNP values were also statistically significantly associated with 30-day all-cause mortality (less than 100 pg/mL [incidence, 0.3%], 100 to less than 200 pg/mL [incidence, 0.7%], 200 to less than 1500 pg/mL [incidence, 1.4%], and 1500 pg/mL or greater [incidence, 4.0%]).
Limitation: External validation of the identified NT-proBNP thresholds in other cohorts would reinforce our findings.
Conclusion: Preoperative NT-proBNP is strongly associated with vascular death and MINS within 30 days after noncardiac surgery and improves cardiac risk prediction in addition to the RCRI.
Primary Funding Source: Canadian Institutes of Health Research.
BACKGROUND: MINS has been independently associated with 30-day mortality after noncardiac surgery. The characteristics and prognostic importance of MINS in vascular surgery patients are poorly described.
METHODS: This was an international prospective cohort study of 15,102 noncardiac surgery patients 45 years or older, of whom 502 patients underwent vascular surgery. All patients had fourth-generation plasma troponin T (TnT) concentrations measured during the first 3 postoperative days. MINS was defined as a TnT of 0.03 ng/mL of higher secondary to ischemia. The objectives of the present study were to determine (i) if MINS is prognostically important in vascular surgical patients, (ii) the clinical characteristics of vascular surgery patients with and without MINS, (iii) the 30-day outcomes for vascular surgery patients with and without MINS, and (iv) the proportion of MINS that probably would have gone undetected without routine troponin monitoring.
RESULTS: The incidence of MINS in the vascular surgery patients was 19.1% (95% confidence interval (CI), 15.7%-22.6%). 30-day all-cause mortality in the vascular cohort was 12.5% (95% CI 7.3%-20.6%) in patients with MINS compared with 1.5% (95% CI 0.7%-3.2%) in patients without MINS (P < 0.001). MINS was independently associated with 30-day mortality in vascular patients (odds ratio, 9.48; 95% CI, 3.46-25.96). The 30-day mortality was similar in MINS patients with (15.0%; 95% CI, 7.1-29.1) and without an ischemic feature (12.2%; 95% CI, 5.3-25.5, P = 0.76). The proportion of vascular surgery patients who suffered MINS without overt evidence of myocardial ischemia was 74.1% (95% CI, 63.6-82.4).
CONCLUSIONS: Approximately 1 in 5 patients experienced MINS after vascular surgery. MINS was independently associated with 30-day mortality. The majority of patients with MINS were asymptomatic and would have gone undetected without routine postoperative troponin measurement.
METHODS: In this international, prospective cohort study of 15,065 patients aged 45 yr or older who underwent in-patient noncardiac surgery, troponin T was measured during the first 3 postoperative days. Patients with a troponin T level of 0.04 ng/ml or greater (elevated "abnormal" laboratory threshold) were assessed for ischemic features (i.e., ischemic symptoms and electrocardiography findings). Patients adjudicated as having a nonischemic troponin elevation (e.g., sepsis) were excluded. To establish diagnostic criteria for MINS, the authors used Cox regression analyses in which the dependent variable was 30-day mortality (260 deaths) and independent variables included preoperative variables, perioperative complications, and potential MINS diagnostic criteria.
RESULTS: An elevated troponin after noncardiac surgery, irrespective of the presence of an ischemic feature, independently predicted 30-day mortality. Therefore, the authors' diagnostic criterion for MINS was a peak troponin T level of 0.03 ng/ml or greater judged due to myocardial ischemia. MINS was an independent predictor of 30-day mortality (adjusted hazard ratio, 3.87; 95% CI, 2.96-5.08) and had the highest population-attributable risk (34.0%, 95% CI, 26.6-41.5) of the perioperative complications. Twelve hundred patients (8.0%) suffered MINS, and 58.2% of these patients would not have fulfilled the universal definition of myocardial infarction. Only 15.8% of patients with MINS experienced an ischemic symptom.
CONCLUSION: Among adults undergoing noncardiac surgery, MINS is common and associated with substantial mortality.
METHODS: We undertook an international prospective cohort study involving patients 18 years of age or older who underwent cardiac surgery. High-sensitivity cardiac troponin I measurements (upper reference limit, 26 ng per liter) were obtained 3 to 12 hours after surgery and on days 1, 2, and 3 after surgery. We performed Cox analyses using a regression spline that explored the relationship between peak troponin measurements and 30-day mortality, adjusting for scores on the European System for Cardiac Operative Risk Evaluation II (which estimates the risk of death after cardiac surgery on the basis of 18 variables, including age and sex).
RESULTS: Of 13,862 patients included in the study, 296 (2.1%) died within 30 days after surgery. Among patients who underwent isolated coronary-artery bypass grafting or aortic-valve replacement or repair, the threshold troponin level, measured within 1 day after surgery, that was associated with an adjusted hazard ratio of more than 1.00 for death within 30 days was 5670 ng per liter (95% confidence interval [CI], 1045 to 8260), a level 218 times the upper reference limit. Among patients who underwent other cardiac surgery, the corresponding threshold troponin level was 12,981 ng per liter (95% CI, 2673 to 16,591), a level 499 times the upper reference limit.
CONCLUSIONS: The levels of high-sensitivity troponin I after cardiac surgery that were associated with an increased risk of death within 30 days were substantially higher than levels currently recommended to define clinically important periprocedural myocardial injury. (Funded by the Canadian Institutes of Health Research and others; VISION Cardiac Surgery ClinicalTrials.gov number, NCT01842568.).