Blaise Pascal and the evidence on the use of multiple arterial grafts for coronary artery bypass surgery after the interim analysis of the Arterial Revascularization Trial

The ROMA trial: why it is needed

PURPOSE OF REVIEW

We herein summarize the current evidence on the clinical outcome associated with the use of single and multiple arterial grafts for coronary bypass surgery and the role and importance of the Randomized comparison of the clinical Outcome of single versus Multiple Arterial grafts (ROMA) trial.

RECENT FINDINGS

Observational evidence suggests that the use of multiple arterial grafts is associated with better clinical outcomes compared to the use of a single arterial graft. Randomized evidence is inconclusive; the 5-year interim analysis of the largest randomized trial on the topic did not show any clinical benefit associated with the use of bilateral versus single internal thoracic arteries, whereas a pooled analysis of the trials comparing the radial artery and the saphenous vein as a second graft showed a significant reduction in follow-up cardiac events using the radial artery. Hidden confounders and treatment allocation biases as well as methodological flaws are the most likely explanation of this contradiction.

SUMMARY

ROMA was conceived based on the lessons learned from a critical analysis of the existing randomized and observational evidence with the aim to provide a definitive answer to the question of the potential clinical benefit of multiple arterial grafts for coronary bypass.

Bilateral internal thoracic artery use in coronary bypass surgery: is there a benefit?

Purpose

Over the past three decades, there have been a plethora of retrospective observational data and meta-analyses which support the hypothesis of improved clinical outcomes using bilateral internal thoracic arteries (BITA) when compared to saphenous vein grafts (SVGs). However, recently published results have brought this thinking into doubt. We discuss the existing literature on the subject and attempt to clarify the appropriate use of BITA in coronary artery bypass surgery (CABG).

Methods

A review of all existing meta-analyses on BITA was conducted to better understand the utility of BITA in CABG. A review of the largest randomized controlled trials on the subject was then compared to the observational data.

Results

In all existing meta-analyses, BITA shows a significant advantage over the use of a single internal thoracic artery (SITA) with SVGs. The two largest randomized controlled trials evaluating BITA failed to show a survival advantage and brought into question the complications associated with BITA.

Conclusions

At present, the use of multiple arterial grafts remains a reasonable choice, particularly in young patients, provided that their use does not increase the operative risk. Further evidence currently being collected may lend a definitive answer in the near future.

Percutaneous coronary intervention versus coronary bypass surgery for unprotected left main disease: a meta-analysis of randomized controlled trials

Background

This meta-analysis of randomized controlled trials (RCTs) was aimed at comparing coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI) for the treatment of unprotected left main coronary disease.

Methods

All RCTs randomizing patients to any type of PCI with stents vs. CABG for left main disease (LMD) were included. Primary outcome was a composite of follow-up death/myocardial infarction/stroke/repeat revascularization. Secondary outcomes were peri-procedural mortality and the individual components of the primary outcome. Incidence rate ratio (IRR) or odds ratio (OR) and 95% confidence intervals (CIs) were pooled using a generic inverse variance method with random effects model. Subgroup analyses were done based on: (I) type of PCI [bare metal stents (BMS) vs. drug-eluting stents (DES)] and; (II) mean SYNTAX score tertiles. Leave one-out analysis and meta-regression were performed.

Results

Six trials were included (4,700 patients; 2,349 PCI and 2,351 CABG). Follow-up ranged from 2.33 to 5 years. PCI was associated with higher risk of follow-up death/myocardial infarction/stroke/repeat revascularization (IRR =1.328, 95% CI, 1.114-1.582, P=0.002) and of repeated revascularization (IRR =1.754, 95% CI, 1.470-2.093, P<0.001). The risk of peri-procedural mortality (OR =0.866, 95% CI, 0.460-1.628, P=0.654), follow-up mortality (IRR =0.947, 95% CI, 0.711-1.262, P=0.712), myocardial infarction (IRR =1.342, 95% CI, 0.827-2.179, P=0.234) and stroke (IRR =0.800, 95% CI, 0.374-1.710, P=0.565) were similar between groups. No differences were found between DES and BMS subgroups. The risk of follow-up death/myocardial infarction/stroke/repeat revascularization with PCI was higher in all SYNTAX tertiles, with a progressive increase from the 1^st to the 3^rd tertile. At meta-regression, higher mean SYNTAX score was associated with higher risk for the primary outcome in the PCI group (beta =0.02, P=0.05), whereas no association was found with female gender, mean age, or diabetes.

Conclusions

CABG remains the therapy of choice for the treatment of unprotected LMD, especially for patients with a high SYNTAX score.