PCI, Surgery Show Similar Long-term Mortality in Diabetic, Nondiabetic Patients

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For patients with multivessel or left main coronary artery disease (CAD), percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) surgery yield similar rates of hard outcomes regardless of diabetic status, according to a meta-analysis published online August 7, 2012, ahead of print in Circulation: Cardiovascular Interventions.

Researchers led by Seung-Jung Park, MD, of Asan Medical Center (Seoul, South Korea), pooled patient-level data from 3 clinical registry studies of multivessel or left main CAD to compare outcomes after PCI (n = 2,789) and CABG (n = 2,986) in diabetic and nondiabetic patients. The 3 registries were MAIN-COMPARE, Asan-Multivessel, and ASAN-MAIN.

No Real Difference at 5 Years

Over a median follow-up of 5.5 years, risk-adjusted mortality and the composite of death, Q-wave MI, or stroke were similar for PCI and CABG in diabetic and nondiabetic patients. PCI was associated with higher risk of repeat revascularization in both diabetic and nondiabetic patients (tables 1 and 2).

Table 1. Five-Year Outcomes: Adjusted Risk for PCI vs. CABG in Diabetic Patients

Table 2. Five-Year Outcomes: Adjusted Risk for PCI vs. CABG in Nondiabetic Patients

There were no interactions between diabetic status and revascularization strategies for death (P = 0.27), the composite outcome (P = 0.97), or repeat revascularization (P = 0.08).

The researchers also assessed the relative treatment benefits of PCI and CABG based on the presence or absence of left main disease and stent types according to diabetic status. Before May 2003, CABG was compared to PCI with BMS, whereas after that time it was compared to DES. The risks of death and serious composite outcomes were similar between the 2 treatment groups, but the rate of repeat revascularization was consistently higher after PCI in each subpopulation. Diabetic status also did not modify the relative treatment effects in these subgroups, regardless of whether or not multivessel CAD was combined with left main disease or whether BMS or DES were used.

According to the authors, observational studies comparing PCI and CABG according to diabetic status have yielded conflicting results and lacked long-term data for DES. In the BARI (Bypass Angioplasty Revascularization Investigation) trial, which used balloon angioplasty as the default PCI strategy, patients with diabetes had substantially better survival rates with CABG vs. PCI. A recent meta-analysis of 10 randomized trials also suggested that mortality was substantially lower with CABG compared with PCI in diabetic patients, while rates were similar between the therapies in nondiabetic patients (Hlatky MA, et al. Lancet. 2009;373:1190-1197). However, other large clinical registries and several subsequent randomized controlled trials have not been able to confirm these findings.

Improvements in Devices, Drugs May Explain Results

Dr. Park and colleagues say one possible explanation for their findings is that “advances in PCI devices and adjunctive pharmacology may lessen the relative benefits of CABG over PCI in diabetic patients with more complex CAD.” They also suggest that in recent years “clinical equipoise among CABG and PCI for mortality and hard clinical endpoints over the long-term period has been ensured on the background of intensive medical therapy.”

Michael E. Farkouh, MD, MSc, of Mount Sinai Medical Center (New York, NY), told TCTMD in a telephone interview that he essentially agreed with this conclusion. “I think [the equipoise between PCI and CABG] also could be due to the types of patients studied as well as other factors that are not taken into account by the risk adjustment. You can very easily think the patients are ‘like for like,’ but in fact there could be differences we just can’t uncover in these types of studies.”

According to Dr. Farkouh, while the Hlatky study is considered the ‘gold standard’ meta-analysis on this topic because of its size and patient-level data, it was conducted in the pre-DES era, raising questions as to the role DES have played in recent years in improving outcomes for diabetic patients.

“It’s unlikely to have this kind of impact on its own, but it could play a role,” Dr. Farkouh said. “The other factor you have to consider is how patients were managed in the DES era compared with prior years. We have statins and other aggressive medical therapies that we didn’t have 10 or 15 years ago. I think what we are seeing is the effect of different methods of treatment and use of DES. But I have to say overall this finding is very surprising and raises interesting questions.”

Dr. Farkouh said large, randomized trials should help answer some of them. New data from one of those studies, the ongoing FREEDOM trial, are scheduled to be presented later this year at the American Heart Association annual meeting, he said. FREEDOM is a multicenter, randomized trial of diabetic patients with multivessel disease (not left main) who were randomized to CABG or multivessel stenting with DES and observed out to 5 years.

 

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Source:
Park D-W, Kim Y-H, Song HG, et al. Long-term outcome of stents versus bypass surgery in diabetic and nondiabetic patients with multivessel or left main coronary artery disease: A pooled analysis of 5,775 individual patient data. Circ Cardiovasc Interv. 2012;Epub ahead of print.

 

 

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• Study Examines Influence of Baseline Factors on Outcomes After CABG, PCI
• Study Compares Stents, Surgery in Diabetics with Multivessel Disease
• Studies Support DES Use in Diabetics, But Results Vary by Device