Meta-analysis: CABG Bests PCI for Long-term Morbidity, Mortality in Multivessel CAD

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Coronary artery bypass grafting (CABG) results in reduced mortality and morbidity compared with percutaneous coronary intervention (PCI) in patients with multivessel coronary artery disease, regardless of diabetic status, according to a meta-analysis published online December 2, 2013, ahead of print in JAMA: Internal Medicine.

Researchers led by Ilke Sipahi, MD, of Acibadem Maslak Hospital (Istanbul, Turkey), analyzed 6,055 patients with multivessel disease from 6 randomized trials completed from 2005 to 2012:

• ARTS
• MASS II
• SoS
• CARDia
• SYNTAX multivessel
• FREEDOM

Patients were treated with either CABG (n = 3,023) or PCI (n = 3,032) and followed out to an average of 4.1 years.

Less Mortality, Morbidity with CABG

CABG was associated with a 27% reduction in total mortality compared with PCI. Surgery was also linked with reductions in MI, repeat revascularization, and MACCE, but tended to result in more strokes. The number needed to treat with CABG vs. PCI was 37 to prevent 1 death and 26 to prevent 1 MI (table 1).

Table 1. Clinical Outcomes: CABG vs. PCI

Results were similar in both diabetic and non-diabetic populations (P = 0.80 for heterogeneity), and there was also no heterogeneity according to type of stent used (P = 0.56 for BMS vs. DES).

CABG Comes Out Ahead

“Although CAD is a leading cause of death worldwide, the optimal treatment strategy for this disease remains to be well defined,” Dr. Sipahi and colleagues write. “There have been important advances in nonsurgical therapies, . . . which have led to improved outcomes in nonsurgically treated patients with multivessel CAD.”

With PCI methods still evolving and surgical outcomes improving, however, “it has become increasingly difficult to answer the ultimate question: ‘What is the best revascularization method for the patient with multivessel CAD?’” they say, adding that most recent CABG vs. PCI trials have been underpowered to detect differences in mortality and morbidity.

The authors observe that, given prior subgroup analyses of different trials, the “benefit of CABG over PCI [may be] limited to patients with diabetes and [the] mortality benefit of CABG seen in our meta-analysis [may be] driven by diabetic patients.” However, they add, the results “strongly [suggest] that CABG should be the revascularization method in patients with multivessel CAD, regardless of their diabetic status.”

Additionally, they advocate for a study adequately powered to detect effects on mortality with CABG vs. medical therapy alone to confirm the benefits of the former.

Patient-level Data Needed

Despite the “growing evidence base that surgery has better mortality outcomes than PCI in complex coronary disease,” Ted Feldman, MD, of Evanston Hospital (Evanston, IL), told TCTMD in a telephone interview that the meta-analysis has a few flaws.

First, “the authors emphasize the idea that they were analyzing studies that reflect contemporary practice and I think that that was a misstatement,” he said. “The perpetual problem with our entire world of trials is that at the time the trials are done, therapy has moved on. So we’re always arguing about how real contemporary practice differs from looking back at study outcomes and this paper looks back quite a ways really.”

Sorin J. Brener, MD, of Weill Cornell Medical College (New York, NY), agreed to a certain extent. “The old one is ARTS which is really ancient [compared with] the way we do things today, but still it’s not that old,” he told TCTMD in a telephone interview. “The only thing we can really argue is that drug-eluting stents weren’t really the best, but altogether [the results fit] very well with what we’ve seen in SYNTAX and FREEDOM. All trials were first-generation DES, so maybe there’s some hope for second-generation DES.”

Dr. Feldman also took issue with the fact that he did not see any “mortality triggers” in the paper. “The magnitude of risk reduction is presented as a relative risk, and it sounds very different to say the risk reduction was 42% relative . . . than 3% absolute,” he explained. “I don’t mean to belittle the importance of it because we are talking about such large populations, but I think the perspective is important to maintain and that some consideration for the absolute mortality outcomes support [is needed].”

Lastly, the fact that the study was missing patient-level data, “diminishes the power of the meta-analysis,” Dr. Feldman noted.

However, “Each one of the trials pretty much shows [the same result] with statistical significance or with a trend, so it’s not surprising that when you put it all together it shows significance,” Dr. Brener concluded.

 

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Source:
Sipahi I, Akay H, Dagdelen S, et al. Coronary artery bypass grafting vs. percutaneous coronary intervention and long-term mortality and morbidity in multivessel disease: Meta-analysis of randomized clinical trials of the arterial grafting and stenting era. JAMA Intern Med. 2013;Epub ahead of print.

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