Predicting Adverse Outcomes in Elective Coronary Artery Bypass Graft Surgery using Pre-operative Troponin I Levels

The use of intraoperative transit time flow measurement can reduce postoperative myocardial injury

OBJECTIVE

This study investigates the relationship between the use of transit time flow measurement (TTFM) and postoperative myocardial injury in off-pump coronary artery bypass grafting (OPCABG).

METHODS

In this retrospective study, we collected basic data from patients hospitalized for OPCABG in the Department of Cardiothoracic Surgery, Changzhou Second People's Hospital Affiliated with Nanjing Medical University. According to the academic research consortium (ARC)-2 definition of significant myocardial injury, we used cardiac troponin I >2380 ng/L as a criterion for significant postoperative myocardial injury. We use logistic regression and forest plots to assess the association of TTFM use with myocardial injury outcomes.

RESULTS

One hundred and forty-six patients were included in this study. The overall median age of these patients was 65.05 years, and 32 (21.92%) experienced a postoperative myocardial injury. TTFM was independently associated with the incidence of postoperative myocardial injury (odds ratio = 0.34 [95% confidence interval = 0.15-0.78]; p = .01), and we found similar trends in regression analyses across subgroups of sex, age, number of bridging vessels, hypertension, diabetes mellitus, BMI, and percutaneous coronary revascularization. One hundred and six patients were followed for 1-year vessel permeability, and seven patients (6.6%) were occluded.

CONCLUSIONS

The use of TTFM is independently associated with a reduced incidence of postoperative myocardial lesions during off-pump coronary bypass surgery. The TTFM procedure in OPCABG deserves to be actively promoted to reduce the incidence of postoperative myocardial injury.

Preoperative troponin levels and outcomes of coronary surgery following myocardial infarction

BACKGROUND

This study evaluates the impact of peak preoperative troponin level on outcomes of coronary artery bypass grafting (CABG) for non-ST-elevation myocardial infarction (NSTEMI).

METHODS

This was a retrospective review of patients undergoing isolated CABG from 2011 to 2018 with the presentation of NSTEMI. Patients were stratified into low- and high-risk groups based on median preoperative peak troponin (1.95 ng/dl). Major adverse cardiac and cerebrovascular events (MACCE) and mortality were compared. Multivariable analysis was performed to model risk factors for MACCE and mortality.

RESULTS

This study included 1211 patients, 607 low-risk (≤1.95 ng/dl) and 604 high-risk (>1.95 ng/dl). Patients were well-matched with respect to age and comorbidity. High-risk patients had lower median preoperative ejection fraction (46.5% [interquartile range {IQR}: 35.0%-55.0%] vs. 53.0% [IQR: 40.0%-58.0%]) and higher incidence of preoperative intra-aortic balloon pump (15.9% vs. 8.73%). Intensive care unit and hospital length of stay were longer in the high-risk group, but increasing troponin level was not associated with prolonged intensive care or hospital length of stay (>4 and >14 days, respectively) after risk adjustment. Postoperative complications and 30-day, 1- and 5-year rates of both MACCE and survival were similar between groups. Peak troponin greater than 1.95 ng/dl was not associated with increased hazards for MACCE, mortality, or readmission in multivariable modeling. In subanalysis, neither increasing troponin as a continuous variable nor peak troponin greater than 10.00 ng/ml were associated with increased hazards for these outcomes.

CONCLUSIONS

Preoperative troponin levels do not appear to be predictive of short- or long-term outcomes following CABG, and clinical decisions regarding surgical revascularization should not be dictated by these measurements.

Does Preoperative Troponin Level Impact Outcomes After Coronary Artery Bypass Grafting?

BACKGROUND

As a marker of myocardial injury, troponin level correlates with adverse outcomes after myocardial infarction (MI). We hypothesized that patients with a higher preoperative troponin level would have increased morbidity and mortality after coronary artery bypass grafting (CABG).

METHODS

Preoperative troponin measurements were available for 1,272 patients who underwent urgent or emergent isolated CABG at our institution from 2002 to 2016. Logistic regression assessed the risk-adjusted effect of peak troponin level on morbidity and mortality. Long-term survival analysis was performed with Kaplan-Meier and Cox proportional hazards models.

RESULTS

Preoperative troponin was positive in 835 patients (65.6%). The median peak troponin for this group was 3.2 ng/mL (interquartile range, 0.6 to 11.9 ng/mL), with a median time from peak troponin to the operation of 3 days (interquartile range, 1 to 4 days). Positive troponin was associated with more significant comorbid conditions and more extensive coronary artery disease. Operative mortality (3.7% versus 1.1%, p = 0.009), major morbidity (11.7% versus 3.9%, p < 0.001), and long-term mortality (median survival 12.5 years versus 13.6 years, p = 0.01) were increased in the positive troponin group. After risk adjustment, positive troponin was not independently associated with increased operative mortality (odds ratio, 2.61; p = 0.053). Adjusted and unadjusted analysis showed the peak preoperative troponin level did not independently predict death at any time point (all odds ratios, 1.0; p > 0.05).

CONCLUSIONS

A positive preoperative troponin correlates with worse outcomes after CABG, but risk adjustment eliminates much of the short-term predictive value of this biomarker. Peak troponin level does not influence outcomes after CABG and is a poor predictor of events when The Society of Thoracic Surgeons predictive models are used.

Years of Life Lost After Complications of Coronary Artery Bypass Operations

BACKGROUND

We currently have an incomplete understanding of which postoperative complications after coronary artery bypass grafting (CABG) are associated with long-term death. The purpose of this study was to find the associations between complications and attributable death.

METHODS

Prospectively collected data on patient characteristics, risk factors, and complications of patients undergoing isolated CABG with 20-year follow-up were analyzed with a Cox regression model to calculate the overall hazard of dying associated with each postoperative complication. An individual's age and hazard of dying from each complication were then used to calculate years of life lost to each complication.

RESULTS

The postoperative mortality rate was 0.79% (69 of 8,773) at 30 days, 2.85% (250 of 8,773) at 180 days, and 6.38% (560 of 8,773) at 2 years. At a median follow-up of 9.8 years, 1,891 patients (21.6%) had died. Postoperative complications occurred in 3,438 patients (39.2%). Cardiac arrest (hazard ratio, 2.153), reoperation (hazard ratio, 1.679), and new dialysis (hazard ratio, 1.64) were the complications with the greatest hazard of death. After adjusting for complication incidence and patient age, cardiac arrest (703 years), reoperation (544 years), atrial fibrillation (470 years), and prolonged mechanical ventilation (371 years) were associated with the greatest number of years of life lost.

CONCLUSIONS

Acute cardiac arrest, reoperation for other cardiac reasons, new dialysis, atrial fibrillation, and prolonged mechanical ventilation are associated with the largest increase in attributable deaths. Prevention and treatment of these complications may improve mortality rates after cardiac operations.

Low platelet activity predicts 30 days mortality in patients undergoing heart surgery

Despite advanced techniques and improved clinical outcomes, patient survival following coronary artery bypass grafting (CABG) is still a major concern. Therefore, predicting future CABG mortality represents an unmet medical need and should be carefully explored. The objective of this study is to assess whether pre-CABG platelet activity corresponds with 30 days mortality post-CABG. Retrospective analyses of platelet biomarkers and death at 30 days in 478 heart surgery patients withdrawn from aspirin or/and clopidogrel. Platelet activity was assessed prior to CABG for aspirin (ASPI-test) with arachidonic acid and clopidogrel (ADP-test) utilizing Multiplate impedance aggregometer. Most patients (n = 198) underwent conventional CABG, off-pump (n = 162), minimally invasive (n = 30), artificial valve implantation (n = 48) or valves in combination with CABG (n = 40). There were 22 deaths at 30 days, including 10 in-hospital fatalities. With the cut-off value set below 407 area under curve (AUC) for the ASPI-test, the 30-day mortality was 5.90% for the lower cohort and 2.66% for patients with significantly higher platelet reactivity (P = 0.038). For the ADP-test with a cut-off at 400AUC, the 30-day mortality was 9.68% for the lower cohort and 3.66% for patients with higher platelet reactivity, representing a borderline significant difference (P = 0.046). Aside from the platelet indices, patients who received red blood cell (RBC) concentrate had a highly significant (P < 0.0001) risk of death at 30 days. Both aspirin and clopidogrel tests were useful in predicting 30 days mortality following heart surgery, suggesting the danger of diminished platelet activity prior to CABG in such high-risk patients. These preliminary evidence supports early discontinuation of antiplatelet therapy for elective CABG and requires adequately powered randomized trials to test the hypothesis and potentially improve survival.