Off-pump coronary artery bypass surgery outcomes in patients with ischaemic left ventricular systolic dysfunction with or without detected viable myocardium

Do patients with ischaemic cardiomyopathy benefit from off-pump coronary bypass surgery? (From the KROK registry)

OBJECTIVES

This study aimed to compare perioperative outcomes and long-term mortality between off-pump coronary artery bypass grafting and on-pump coronary artery bypass grafting in patients with ischaemic cardiomyopathy who had a left ventricle ejection fraction of ≤35%.

METHODS

A retrospective cohort analysis was conducted using data from the Polish National Registry of Cardiac Surgery Procedures database, encompassing patients who underwent isolated coronary artery bypass grafting in Poland between 2012 and 2022. Patients were divided into two groups: on-pump and off-pump. Propensity score matching was used to balance the groups. The primary outcome was long-term all-cause mortality following surgical revascularization.

RESULTS

A total of 9920 patients were included, with 3116 patients in each group after propensity score matching. The median follow-up period was 4 years. The off-pump group was associated with a lower 30-day mortality rate (6.4% vs 9.1%, P = 0.002) and fewer perioperative complications. However, long-term survival analysis revealed a modest but statistically significant advantage for on-pump group at the 10-year follow-up (P = 0.047).

CONCLUSIONS

Off-pump provides short-term benefits, including reduced early mortality and fewer complications compared to on-pump technique. However, these advantages do not translate into improved long-term survival, where on-pump demonstrates a slight benefit. The choice between off-pump and on-pump technique should be individualized based on patient-specific factors and surgical expertise.

Assessment of Myocardial Viability in Ischemic Cardiomyopathy With Reduced Left Ventricular Function Undergoing Coronary Artery Bypass Grafting

BACKGROUND

We aim to provide a comprehensive review of the current state of knowledge of myocardial viability assessment in patients undergoing coronary artery bypass grafting (CABG), with a focus on the clinical markers of viability for each imaging modality. We also compare mortality between patients with viable myocardium and those without viability who undergo CABG.

METHODS

A systematic database search with meta-analysis was conducted of comparative original articles (both observations and randomized controlled studies) of patients undergoing CABG with either viable or nonviable myocardium, in EMBASE, MEDLINE, Cochrane database, and Google Scholar, from inception to 2022. Imaging modalities included were dobutamine stress echocardiography (DSE), cardiac magnetic resonance (CMR), single-photon emission computed tomography (SPECT), and positron emission tomography (PET).

RESULTS

A total of 17 studies incorporating a total of 2317 patients were included. Across all imaging modalities, the relative risk of death post-CABG was reduced in patients with versus without viability (random-effects model: odds ratio: 0.42; 95% confidence interval: 0.29-0.61; p < 0.001). Imaging for myocardial viability has significant clinical implications as it can affect the accuracy of the diagnosis, guide treatment decisions, and predict patient outcomes. Generally, based on local availability and expertise, either SPECT or DSE should be considered as the first step in evaluating viability, while PET or CMR would provide further evaluation of transmurality, perfusion metabolism, and extent of scar tissue.

CONCLUSION

The assessment of myocardial viability is an essential component of preoperative evaluation in patients with ischemic heart disease undergoing surgical revascularization. Careful patient selection and individualized assessment of viability remain paramount.

Outcomes of Coronary Artery Bypass Grafting in Patients With Poor Myocardial Viability: A Systematic Review and Meta-Analysis of the Last Decade

OBJECTIVES

Our objective is to assess whether the presence of myocardial viability is a predictor of mortality among patients undergoing coronary artery bypasss grafting (CABG) through a systematic review meta-analysis.

METHODS

Comprehensive review of EMBASE and PubMed in accordance with PRISMA guidelines, including studies of patients undergoing CABG with assessment of myocardial viability and recorded long-term mortality, age and sex. Studies were restricted to the last decade, and data were stratified by imaging modality (magnetic resonance imaging [MRI] or nuclear medicine). Random-effects model for assessing pooled effect, heterogeneity assessment using Chi-square and I² statistics, publication bias assessed by funnel plots and Egger's test.

RESULTS

Meta-analysis of contemporary data (January 2010 to October 2020) yielded 3,621 manuscripts of which 92 were relevant, and 6 appropriate for inclusion with 993 patients. Pooled analysis showed that patients with non-viable myocardium undergoing CABG are at 1.34 times the risk of mortality compared to those with viable myocardium (95% CI 1.01-1.79, p=0.05). Subgroup analysis of the MRI or nuclear medicine modalities was not statistically significant and there was no confounding by age or sex in meta-regression. There was significant heterogeneity in imaging modality and diagnostic criteria, but heterogeneity between study findings was low with an I² statistic of 29%. The risk of publication bias was moderate on the Newcastle-Ottawa Scale), but not statistically significant (Egger's Test coefficient=1.3, 95%CI -0.35-2.61, p=0.10).

CONCLUSIONS

There is a multitude of methods for assessing cardiac viability for coronary revascularisation surgery, making meta-analyses fraught with limitations. Our meta-analysis demonstrates that the finding of non-viable myocardium can not be used draw conclusions for risk assessment in coronary surgery.