CABG Trumps PCI for Survival in CAD Even Without Diabetes

Marlene Busko

December 02, 2013

ISTANBUL, TURKEY — In patients with multivessel coronary artery disease, CABG resulted in "clearly superior" survival and lower risk of MI compared with PCI, whether or not the patient had diabetes, in a new meta-analysis[1] .

Specifically, in six randomized trials, the patients who underwent CABG, compared with PCI, showed a 27% reduction in risk of total mortality and a 42% reduction in risk of MI (p<0.001 for both differences) over an average follow-up of 4.1 years.

"Our analysis for the first time unequivocally shows that stenting leads to higher mortality and more frequent heart attacks as compared with CABG in patients with multivessel CAD," with and without diabetes, lead author Dr Ilke Sipahi (Acibadem University, Istanbul, Turkey) told heartwire in an email.

The study also "clearly shows that most patients with multivessel disease and preserved ejection fraction should undergo CABG, especially if they care about [reduced risk of mortality and MI]," he added. "We should offer most of [these patients] CABG first."

The meta-analysis is published online December 2, 2013 in JAMA Internal Medicine.

A Meta-Analysis Powered to Compare Mortality

Recent clinical trials comparing CABG vs PCI for multivessel disease were underpowered to detect a difference in all-cause mortality, Sipahi and colleagues write. However, as "PCI methods continue to evolve and surgical outcomes improve, it has become increasingly difficult to answer the ultimate question: 'What is the best revascularization method for the patient with multivessel CAD?' " they note.

To investigate this, they identified six randomized trials of CABG vs PCI, which enrolled 6055 patients. The trials— ARTS , MASS II , SOS , CARDIA , SYNTAX , and FREEDOM —differed in the type of stents used and the percentage of diabetic patients enrolled. The patients had two-vessel or three-vessel CAD.

Characteristics of Trials of CABG vs PCI

Trial Published Patients, n Patients with diabetes (%)* Type of stents in PCI arm
ARTS 2005 1174 18 Bare metal
MASS II 2007 408 26 Bare metal
SOS 2008 988 15 Bare metal
CARDIA 2010 490 100 69% sirolimus-eluting, 31% bare metal
SYNTAX 2011 1095 36 100% paclitaxel-eluting
FREEDOM 2012 1900 100 51% sirolimus-eluting, 43% paclitaxel-eluting, 6% other drug-eluting

*Approximate percentage

The meta-analysis showed that if CABG were preferred over PCI in 37 patients, it would save one life, and if CABG were preferred over PCI in 26 patients, it would prevent one MI—in a 4.1-year follow-up.

CABG also led to a "dramatic reduction" in repeat revascularization and major adverse cardiovascular and cerebrovascular events (MACCE) (the combined end point of death, nonfatal MI, nonfatal stroke, and repeat revascularization). The number needed to treat was seven for repeat revascularization and 10 for MACCE.

However, in addition to these benefits, there was a nonsignificant trend to excess strokes with CABG: the number needed to harm was 105 to cause one excess stroke with CABG.

Whether trials enrolled only patients with diabetes or mainly nondiabetic patients, the reduction in morality was very similar: 25% vs 28%, respectively. The improved survival was similar with bare-metal and drug-eluting stents.

Although this study did not examine outcomes with medical therapy, if "CABG is superior to stenting for prevention of death, then it must be superior to medical therapy as well," since other studies have shown that in stable CAD, major events are similar with either medical therapy or stenting, Sipahi said.

"Clear Superiority" of CABG over PCI

In an accompanying editor's note[2], Dr Mitchell H Katz (Los Angeles County Department of Health, CA) points out that since stenting is less invasive than surgery, it might appear to be an attractive option for some patients with multivessel CAD. However, the current meta-analysis demonstrated the "clear superiority" of CABG over PCI, he observes.

It also points to misconceptions about surgery. "Some patients who are unwilling to have surgery may agree to a percutaneous procedure, even though it may have a greater mortality risk than CABG and may cause them more harm than medical therapy," he notes.

Future trials should look at all treatment options—surgery, stenting, and medical therapy—to be able to better counsel patients with multivessel CAD about potential outcomes with these three treatment strategies, he writes.

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