Radial-artery grafts outperform saphenous-vein grafts when used in CABG: The RADIAL trial

1. Patients undergoing coronary artery bypass grafting (CABG) who received a radial-artery graft rather than a saphenous-vein graft (both groups also received an internal-thoracic-artery graft) experienced fewer major adverse cardiac events at a mean follow-up of 60 months.

2. At a mean follow-up of 50 months, angiography showed patients in the radial-artery group had a lower rate of graft occlusion.

Evidence Rating Level: 1 (Excellent)

Study Rundown: At present most CABG procedures utilize saphenous-vein and internal-thoracic-artery grafts. Though various trials support the use of radial-artery grafts as they show greater patency during follow-up, these trials were often underpowered to detect clinical adverse events. The Radial Artery Database International Alliance (RADIAL) project seeks to assess multiple randomized trials with patients randomized to receive either radial-artery or saphenous-vein grafts during CABG and assess differences in clinical outcomes. The primary outcome, a composite of major cardiac events and/or death, was significantly lower after a mean follow-up of 60 months in patients receiving a radial-artery graft. Follow-up angiography showed less occlusion in radial-artery grafted patients, but incidence of death was not significantly different.

Strengths of this study include relatively extended follow-up data and a focus on clinically relevant outcomes. Limitations include the small number of patients included in the study and the analysis being performed using patients from different trials

Click to read the study, published in NEJM

Relevant Reading: Radial artery grafts vs saphenous vein grafts in coronary artery bypass surgery: a randomized trial

In-Depth [meta-analysis]: This meta-analysis evaluated 612 articles, ultimately including 6 which had a combined total of 1036 patients (radial-artery, n = 534; saphenous-vein, n = 502). All original studies randomized patients undergoing CABG to received either radial-artery or saphenous-vein grafting as a supplement to internal-thoracic-artery grafting and had greater than 2 years of patient follow-up. Patient level data from individual trials was collected and evaluated for consistency. The primary outcome was a composite of major adverse cardiac events including death, myocardial infarction, and repeat revascularization. A key secondary outcome was graft patency at individual study defined follow-up. At a mean follow-up time of 60 months, combined cardiac adverse events was were significantly fewer in the radial-artery group (25 vs. 39 events per 1000 patients-years; hazard ratio [HR], 0.67; 95% confidence interval [CI], 0.49 to 0.90; p = 0.01). Myocardial infarction and revascularization events were less frequent in the radial-artery group (both p < 0.05), though death was not significantly different between the two groups (HR, 0.90; 95% CI, 0.59 to 1.41; p = 0.68). At a mean follow-up angiography time of 50 months, graft occlusion incidence was less in the radial-artery group (HR, 0.44; 95%, 0.28 to 0.70; p < 0.001).

Image: PD

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