DES "Noninferior" to MIDCAB for Isolated LAD Disease, Small Study Suggests

Shelley Wood

June 16, 2009

June 16, 2009 (Leipzig, Germany) — A small randomized study comparing minimally invasive coronary artery bypass surgery (MIDCAB) with PCI using sirolimus-eluting stents suggests that both approaches are reasonable options in patients with isolated proximal left anterior descending (LAD) coronary artery disease [1]. While repeat procedures were more common for PCI, periprocedural events were more common in the MIDCAB group.

The results appear in the June 23, 2009 issue of the Journal of the American College of Cardiology.

As the authors, led by Dr Holger Thiele (University of Leipzig, Germany), point out, proximal LAD disease warrants special consideration, given the large area of myocardium at jeopardy and the associated worse prognosis with this form of CAD. MIDCAB has been promulgated in recent years as the preferred treatment strategy for proximal LAD, following randomized PCI-vs-MIDCAB studies that pointed to higher reintervention rates following PCI. But drug-eluting stents (DES) are increasingly used to treat isolated LAD disease, although whether they do indeed reduce reintervention rates in this setting has not been specifically tested, Thiele et al write.

Their study randomized 130 patients to either PCI with a sirolimus-eluting stent or MIDCAB surgery, then followed patients for 12 months. They report that MACE rates at one year--combining cardiac death, MI, and need for PCI--were identical in both groups, at 7.7%, therefore meeting the primary clinical end point of noninferiority for PCI. Symptom relief and quality-of-life end points were also similar between the two groups. MACE in the MIDCAB group was driven entirely by periprocedural MIs--a "surprisingly" high rate compared with other studies. None of these MIs, however, appeared to have a bearing on one-year outcomes.

Of note, however, individual end points within the composite were not the same between the groups. Noninferiority was demonstrated for PCI in terms of the difference in death and MI (1.5% vs 7.7%), but was not seen for repeat target vessel revascularization, which was higher in the PCI group (6.2%, as compared with 0% for MIDCAB).

Study Too Small to Test Superiority

To heartwire , Thiele emphasized that the trial was not powered to look at whether PCI was superior to MIDCAB in any way, such that no conclusions can be drawn about the lower death/MI rates with PCI than for MIDCAB. "Indeed, it seems to be superior, but testing for superiority is not allowed due to the sample size," he said.

He also cautioned that the trial cannot be viewed with the same lens as the recent SYNTAX trial, comparing PCI with CABG in the setting of complex coronary disease. "We looked only at one-vessel disease, [whereas] SYNTAX looked at three-vessel disease," Thiele noted.

In a nutshell, he said, "The study is powered to show noninferiority and the primary study end point was met by the trial. Thus, it means that PCI is similar to MIDCAB for single-vessel proximal LAD disease." While event curves may be expected to separate over time, the authors note in the paper that they now have median follow-up out to 42 months, and no differences in MACE have emerged between the groups.

The authors also point out that patient preferences play an important role in deciding which procedure is chosen. In their analysis, 19 of the patients initially screened for the study refused to be randomized, stating a preference for stenting, while just one patient stated a preference for surgery.

The study was supported by an unrestricted grant from Cordis, Germany.


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