[Physician Comments] CABG demonstrates better rates of survival versus PCI in diabetic patients: FREEDOM trial

Jan 13th – A look back on a high-impact study, featuring comments from PI Dr. Valentin Fuster and NEJM editor Dr. Mark Hlatky.

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Image: PD/NIH

 1. Diabetic patients with multi-vessel coronary artery disease who underwent coronary artery bypass grafting (CABG) experienced lower rates of myocardial infarction and all-cause mortality, but higher rates of stroke compared to those who underwent percutaneous coronary intervention (PCI).

2. Differences in these three clinical endpoints were consistent across subgroups of disease severity in each treatment arm and across PCI subtypes of no stent, bare metal stent, and drug-eluting stents.

In diabetic patients with multi-vessel disease, CABG significantly reduced rates of myocardial infarction and death when compared with PCI. Though results remained consistent across all subgroups in each arm, because of low numbers they subgroup comparisons were not appropriately powered for statistical significance. The study was also not blinded, and there is a broad variability in the extent of cardiovascular disease as assessed by angiographic complexity (SYNTAX) score in both study arms. However, this was felt to reflect the overall heterogeneity of patient populations encountered commonly in practice.

Click to read the study in NEJM 

Click to read an accompanying editorial in NEJM

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Image: PD/NIH.

Dr. Valentin Fuster, M.D., Principle Investigator of the FREEDOM Trial, talks to 2 Minute Medicine: PROFESSOR of Medicine, Cardiology, at Mount Sinai Hospital
vfphotowinter2010“Studies 8 years ago showed worse outcomes post-PCI for diabetic patients, which is consistent with our understanding of diabetes as affecting arteries diffusely. However practice did not change significantly for these patients, with practitioners thinking that newer drug eluting stents rendered the old data irrelevant. The FREEDOM trial used drug-eluting stents, an average of 4.2 per patient, and still had these striking differences [in outcomes between CABG and PCI for diabetic patients].”

Dr. Mark A. Hlatky M.D., editorial author in NEJM talks to 2 Minute Medicine: Professor of Health Research and Policy and of Medicine (Cardiovascular Medicine) and Stanford Health Policy Fellow

“I do think more patients with diabetes and multi-vessel CAD will undergo CABG as a result of FREEDOM.  I suspect that clinical guidelines for coronary revascularization will be updated to reflect these findings and that will move more patients towards CABG.  I do think we need to start conversations about revascularization earlier in the management cycle, but it might be hard to accomplish that.  Primary care doctors should be more involved – they can give sound advice earlier.”

 

 1. Diabetic patients with multi-vessel coronary artery disease who underwent coronary artery bypass grafting (CABG) experienced lower rates of myocardial infarction and all-cause mortality, but higher rates of stroke compared to those who underwent percutaneous coronary intervention (PCI).

2. Differences in these three clinical endpoints were consistent across subgroups of disease severity in each treatment arm and across PCI subtypes of no stent, bare metal stent, and drug-eluting stents.

Primer: Minimally invasive techniques such as PCI have become increasingly popular options for patients with coronary artery disease. However, diabetic patients were observed to experience more complications with PCI when compared with CABG in various trials. In 1995, the NHLBI issued a clinical alert recommending against PCI in diabetic patients.

Despite this, diabetic patient management has shifted towards more rather that fewer PCI procedures, with practitioners citing drug-eluting stents and other recent improvements in PCI technology as limiting the relevance of the older evidence. The FREEDOM randomized controlled trial was created to compare modern techniques in both procedures in a large sample of diabetic patients.

Background reading:

1. The Bypass Angioplasty Revascularization Investigation (BARI) Investigators. Comparison of coronary bypass surgery with angioplasty in patients with multivessel disease. N Engl J Med. 1996; 335:217-25.

2. National Heart, Lung, and Blood Institute (NHLBI). Clinical alert: bypass over angioplasty for patients with diabetes. US National Library of Medicine, National Institutes of Health, September 21, 1995.

This [randomized controlled trial]: 1900 patients in were randomized to CABG or PCI with predominantly paclitaxel or sirolimus-eluting stents. Optimal glucose control through medical therapy was maintained in both treatment arms. Primary outcomes were death from any cause, nonfatal myocardial infarction, and nonfatal stroke. The 5-year mortality rate was 10.9% CABG group and 16.3% in the PCI group (P=.049). Myocardial infarctions occurred at a rate of 6.0% CABG and 13.9% PCI (P<.001), and strokes at a rate of 5.2% CABG and 2.4% PCI (P=.03) during the 5 year follow-up period. Overall, the primary outcomes occurred with 5-year rates of 18.7% in the CABG group versus 26.6% in the PCI group (P=.005). The benefit of CABG vs. PCI in terms of lower rates of primary outcomes overall was consistent across all specified subgroups.

In sum: In diabetic patients with multi-vessel disease, CABG significantly reduced rates of myocardial infarction and death when compared with PCI. Though results remained consistent across all subgroups in each arm, because of low numbers they subgroup comparisons were not appropriately powered for statistical significance. The study was also not blinded, and there is a broad variability in the extent of cardiovascular disease as assessed by angiographic complexity (SYNTAX) score in both study arms. However, this was felt to reflect the overall heterogeneity of patient populations encountered commonly in practice.

Click to read the study in NEJM 

Click to read an accompanying editorial in NEJM

 By [GS] and [AH] 

© 2013 2minutemedicine.com. All rights reserved. No works may be reproduced without written consent from 2minutemedicine.com. DISCLAIMER: Posts are not medical advice and are not intended as such. Please see a healthcare professional if you seek medical advice.

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1f636eeGina Siddiqui: Gina is a 3rd year M.D. candidate at the Perelman School of Medicine, University of Pennsylvania.

 

 

 

 

Allen Ho: Allen is a 4th year M.D. candidate at Harvard Medical School.

 

 

 

 

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