Early and late prognostic implications of coronary artery bypass timing after myocardial infarction

Determinants of Early and Late In-Hospital Mortality After Acute Myocardial Infarction A Sub-analysis of the OBTAIN Registry

BACKGROUND

Predictors of in-hospital mortality after myocardial infarction (MI) have been reported dichotomously: survival vs death. Predictors of time from admission to death have not been reported.

METHODS

A total of 7335 patients were enrolled in a prospective multicentre registry of acute MI. In-hospital mortality was classified by time from admission as acute (≤ 2 days), subacute (3 to 7 days), late (8 to 14 days), and very late (≥ 15 days) to identify factors associated with time to death in patients who died before discharge. Patient and MI characteristics, in-hospital interventions, and electrocardiographic findings were screened for differences in time to in-hospital death.

RESULTS

In-hospital death affected 351 patients (4.8%). Mean age was 72.0 ± 12.4 years, and 40.5% were female patients. Median survival was 5 days (interquartile range: 2-12), and 41% of in-hospital deaths occurred after 1 week. Cardiac biomarkers and ejection fraction were not related to time to in-hospital death. Previous MI, systolic blood pressure, pharmacologic therapy, and interventional treatments were different among the 4 groups. The factors associated with late in-hospital death were coronary artery bypass graft surgery (CABG), new-onset atrial fibrillation or flutter, heart failure or pulmonary edema, bleeding, and lung disease. Acute and subacute in-hospital death was associated with ST-elevation MI, lower systolic blood pressure, and cardiac arrest on admission. CABG was performed in 12% of post-MI patients who died in hospital.

CONCLUSIONS

Clinical risk factors for in-hospital mortality evolve over time immediately after acute MI. Understanding the time-dependent risk factors may allow for the development of new approaches to curtail the "later" in-hospital mortality.

Meta-Analysis of Nonrandomized Studies to Assess the Optimal Timing of Coronary Artery Bypass Grafting After Acute Myocardial Infarction

The optimal timing of coronary artery bypass grafting (CABG) in patients after an acute myocardial infarction (MI) is unknown. We performed a systematic review and meta-analysis of studies comparing mortality rates in patients who underwent CABG at different time intervals after acute MI. Bias assessments were completed for each study, and summary of proportions of all-cause mortality were calculated based on CABG at various time intervals after MI. A total of 22 retrospective studies, which included a total of 137,373 patients were identified. The average proportion of patients who died when CABG was performed within 6 hours of MI was 12.7%, within 6 to 24 hours of MI was 10.9%, within 1 day of MI was 9.8%, any time after 1 day of MI was 3.0%, within 7 days of MI was 5.9%, and any time after 7 days of MI was 2.7%. Interstudy heterogeneity, assessed using I² values, showed significant heterogeneity in death rates within subgroups. Only 1 study accounted for immortal time bias, and there was a serious risk of selection bias in all other studies. Confounding was found to be a serious risk for bias in 55% of studies because of a lack of accounting for type of MI, MI severity, or other verified cardiac risk factors. The current publications comparing timing of CABG after MI is at serious risk of bias because of patient selection and confounding, with heterogeneity in both study populations and intervention time intervals.

The timing of surgical revascularisation in acute myocardial infarction: when should we intervene?

INTRODUCTION

Coronary artery bypass grafting (CABG) is a crucial intervention in acute myocardial infarction (AMI), particularly when AMI is not amenable for management with primary percutaneous coronary intervention (PCI). To optimise outcome in these patients, surgical teams must consider a host of predictive factors, with the most prominent being the timing of CABG. Despite numerous studies exploring timing of CABG following AMI in the past, optimal surgical timing remains controversial. The mortality rates vary with timing of CABG, but confounding factors such as age, impaired pulmonary function, renal insufficiency, and poor left ventricular function may contribute to varied outcomes reported.

EVIDENCE ACQUISITON

An electronic literature search of articles that discussed acute myocardial presentation and urgent in-patient or elective CABG was conducted.

EVIDENCE SYNTHESIS

The evidence was synthesised based on each reported article and their outcomes.

CONCLUSIONS

Current literature suggests multiple factors can guide CABG timing including, type of AMI at initial presentation, distinctive pathological status and patient characteristics. Thus, there is a need for large, multi-centre studies to identify optimal CABG timing in complex coronary artery disease or failed PCI in patients with AMI. Future guidelines should emphasise patient cohorts by taking their risk factors into consideration. As such, a need for greater cardiac screening methods and development of scoring systems can aid in the optimisation of CABG timing.

Timing of coronary artery bypass grafting after acute myocardial infarction: does it influence outcomes?

Introduction

The optimal timing of coronary artery bypass grafting (CABG) operations in patients with recent acute myocardial infarction (AMI) remains unclear.

Aim

To assess the influence of timing on post-operative outcomes in patients undergoing CABG following AMI.

Material and methods

In this retrospective analysis 12,224 consecutive patients undergoing CABG were included. 2477 (20.5%) patients had a history of AMI. Based on timing, patients were divided into 3 groups: those operated within 7 days of AMI; those operated after 7 days but within 1 month; and a third group operated after 1 month but within 3 months. The 3 groups were compared in terms of baseline, intra-operative, and post-operative morbidity and mortality. Multivariate analysis was carried out to assess the independent influence of timing of CABG on outcomes.

Results

There was no difference in terms of previous neurological events (p = 0.554), presence of carotid artery disease (p = 0.555), prevalence of hypertension (p = 0.119), diabetes (p = 0.144), hypothyroidism (p = 0.53), chronic obstructive pulmonary disease (p = 0.079), peripheral vascular disease (p = 0.771), and impaired left ventricular function (p = 0.072). On univariate analysis, mortality risk was highest between 1 week and 1 month (p = 0.003). Multivariate analysis showed that the closer the MI and CABG duration, the higher the mortality (co-efficient -0.517; p = 0.019; odds ratio = 0.596; 95% CI: 0.388-0.917).

Conclusions

The duration between MI and CABG has a direct influence on outcomes after CABG. While it is clear that the longer the duration between MI and CABG, the lower the mortality risk, it is however difficult to decide on an exact cut-off time frame.

Early surgical myocardial revascularization in non-ST-segment elevation acute coronary syndrome

Background

In non-ST-elevation myocardial infarction (NSTEMI) there is no consensus regarding optimal time point for coronary artery bypass grafting (CABG). Recent findings suggest that long-term outcomes are improved in early-revascularized NSTEMI patients. However, it has been stated that early surgery is associated to increased operative risk. In this study, we wanted to elucidate if early CABG in non-ST-elevation acute coronary syndrome can be performed safely.

Methods

We performed a monocentric-prospective observational study within a 2-year interval. A total of 217 consecutive patients (41 female, age 68.9±10.2, ES II 6.62±8.56) developed NSTEMI and underwent CABG. Patients were divided into two groups according to the time point of coronary artery bypass after symptom onset (group A: <72 h; group B: >72 h). Endpoints included 6-month mortality and incidence of MACE (death, stroke or re-infarction).

Results

There were no differences regarding mortality between both groups (30 days: group A 2.4% vs. group B 3.7%; P=0.592; 6 months: 8.4% vs. 6.0%; P=0.487). Incidence of MACE in the 6-month follow-up was also similar in both groups (group A: 9.6% vs. 9.7%, P=0.982). Regression analysis revealed as independent risk factors for mortality in the entire cohort ES II OR 1.045 (95% CI: 1.004-1.088). ES II remained an independent prognostic factor in group A OR 1.043 (95% CI: 1.003-1.086) and group B OR 1.032 (95% CI: 1.001-1.063).

Conclusions

Early revascularized patients showed a higher level of illness. However, results of early CABG were comparable to those following delayed revascularization. Moreover, EuroSCORE II was determined as independent risk factors for mortality.

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.

Training in Coronary Artery Bypass Surgery: Tips and Tricks of the Trade

Coronary artery bypass is often the first procedure cardiac surgeons are confronted with during their residencies. This article discusses the surgical steps and the potential difficulties encountered during this procedure and how they can be solved. The "point of view" of an experienced surgeon is provided to the trainees and to the readers.

Early Referral to Coronary Artery Bypass Grafting Following Acute Coronary Syndrome, Trends and Outcomes from the Acute Coronary Syndrome Israeli Survey (ACSIS) 2000-2010

BACKGROUND

Limited information exists on whether changes in medical practices over the study decades have affected the outcomes of acute coronary syndrome (ACS) patients who undergo early coronary artery bypass surgery (CABG) during index hospitalisation.

METHODS

Data on trends for early CABG referral and associated outcomes were obtained among 11,485 ACS patients enrolled in the biennial Acute Coronary Syndrome Israeli Surveys (ACSIS) 2000-2010.

RESULTS

Among 11,485 patients, 566 (5%) were referred to early CABG. These patients displayed higher risk characteristics, including Killip class >II, anterior myocardial infarction, greater left ventricular dysfunction, and more frequent use of mechanical ventilation and intra-aortic balloon pump (all p<0.01). Nevertheless, mortality rates of patients referred to early CABG vs. treated with percutaneous coronary intervention (PCI) or medically, was similar (11.4% vs. 10.2%; log-rank p-value=0.40). There was a significant decline in the referral trend over the study decade (6.7% - 1.7%; p<0.001). One year survival was similar between patients referred to early CABG during the late (years: 2006-2010) vs. early (years: 2000-2005) period (85.7% vs. 90%; log-rank p-value=0.15), whereas, among patients who didn't undergo early CABG, and underwent percutaneous coronary intervention (PCI) or medical management only, enrolment during the late periods was associated with a significant survival benefit (91.5% vs. 88.1%; log-rank p-value<0.001).

CONCLUSIONS

Over the study decade there was a significant decline in referral for early CABG, without a difference in the one-year mortality between the early and non-early CABG group.

Optimal Timing of Surgical Revascularization for Myocardial Infarction and Left Ventricular Dysfunction

Background:

The optimal timing of surgical revascularization for patients presenting with ST-segment elevation myocardial infarction (STEMI) and impaired left ventricular function is not well established. This study aimed to examine the timing of surgical revascularization after STEMI in patients with ischemic heart disease and left ventricular dysfunction (LVD) by comparing early and late results.

Methods:

From January 2003 to December 2013, there were 2276 patients undergoing isolated coronary artery bypass grafting (CABG) in our institution. Two hundred and sixty-four (223 male, 41 females) patients with a history of STEMI and LVD were divided into early revascularization (ER, <3 weeks), mid-term revascularization (MR, 3 weeks to 3 months), and late revascularization (LR, >3 months) groups according to the time interval from STEMI to CABG. Mortality and complication rates were compared among the groups by Fisher's exact test. Cox regression analyses were performed to examine the effect of the time interval of surgery on long-term survival.

Results:

No significant differences in 30-day mortality, long-term survival, freedom from all-cause death, and rehospitalization for heart failure existed among the groups (P > 0.05). More patients in the ER group (12.90%) had low cardiac output syndrome than those in the MR (2.89%) and LR (3.05%) groups (P = 0.035). The mean follow-up times were 46.72 ± 30.65, 48.70 ± 32.74, and 43.75 ± 32.43 months, respectively (P = 0.716). Cox regression analyses showed a severe preoperative condition (odds ratio = 7.13, 95% confidence interval 2.05–24.74, P = 0.002) rather than the time interval of CABG (P > 0.05) after myocardial infarction was a risk factor of long-term survival.

Conclusions:

Surgical revascularization for patients with STEMI and LVD can be performed at different times after STEMI with comparable operative mortality and long-term survival. However, ER (<3 weeks) has a higher incidence of postoperative low cardiac output syndrome. A severe preoperative condition rather than the time interval of CABG after STEMI is a risk factor of long-term survival.