Poor Med Adherence After PCI vs CABG Gives Surgery the Edge

Marlene Busko

October 27, 2016

NEW YORK, NY — Compliance with appropriate medical therapy (antiplatelets, lipid-lowering agents, and beta-blockers) after PCI or CABG has a "dramatic" impact on long-term major adverse cardiac event (MACE)–free survival, researchers report[1]. The study of more than 3000 patients followed for up to 8 years was published October 24, 2016 in Circulation.

The findings showed that "regardless of what interventional strategy is chosen, the importance of adherence to appropriate medical therapy cannot be overemphasized," Dr Paul Kurlansky (Columbia University, New York, NY) told heartwire from Medscape.

Moreover, MACE—all-cause mortality, nonfatal MI, and repeat intervention—were more likely among patients who had PCI vs CABG, in an analysis of matched patients who did not comply with medical therapy.

"Although these findings certainly warrant confirmation with larger and more contemporary patient populations, what they suggest is that for patients who might be appropriate candidates for either CABG or PCI who are less likely to be adherent to their medical regimen, CABG may be a better long-term solution," Kurlansky said.

Clinicians need to recognize how important optimal medication adherence is after coronary revascularization, and optimal medication adherence "should be incorporated into all future outcome studies," he added.

PCI vs CABG Well-Studied; Postprocedure Pill Compliance Unknown

Probably few interventions have been as well studied as PCI vs CABG, but "remarkably" it remains unknown how adherence to recommended therapy after these interventions affects long-term outcomes, Kurlansky and colleagues write.

They aimed to investigate this in patients who had non-ST-segment-elevation MI and subsequent coronary revascularization in eight community hospitals that were part of the Coronary Artery Revascularization Evaluation (CARE) registry.

The researchers identified 973 patients who had CABG and 2255 patients who had PCI in 2004 and were followed for up to 8 years.

Compared with patients in the PCI group, those who had CABG surgery were more likely to smoke (53% vs 45%) or have triple-vessel disease (41% vs 18%) or a lower ejection fraction (EF 50% vs 54%) or to have had a previous stoke (8% vs 4.7%), and they were less likely to have previous CABG (6% vs 23%).

The researchers defined adherence to optimal medical therapy, based on current recommendations. "Both the Society of Thoracic Surgeons and the National Quality Forum currently recommend that all patients undergoing CABG surgery be discharged on antiplatelet medication [usually aspirin], lipid-lowering medication [usually a statin], and beta-blockers," Kurlansky explained. Guidelines also recommend that antiplatelet and lipid-lowering therapies be continued somewhat indefinitely, whereas continuation of long-term beta-blocker treatment should generally be based on clinical findings.

Similarly, according to guidelines, patients who have PCI should receive dual antiplatelet therapy for about a year, depending on the stent type and their risk factors, and they should get lipid-lowering therapy with statins, but beta-blockers have not been well studied in this such patients, he continued.

Medications Might "Cancel Out" Surgery Benefits

MACE-free survival was significantly better in patients who had CABG or PCI who adhered to appropriate recommended antiplatelet, lipid-lowering, and beta-blocker therapy (P=0.001 for all three medications).

Among well-matched patients who adhered to optimal medical therapy, MACE-free survival was similar in patients who had undergone CABG or PCI (P=0.574).

However, among well-matched patients who did not adhere to therapy, MACE-free survival was superior after CABG vs after PCI (P=0.001).

The study was not powered to determine the relative contribution of adherence of individual medications to outcome, and patients who took the medications as recommended may also have been more likely to adopt healthy habits, Kurlansky conceded.

It was not surprising that adherence to medication had an impact on PCI and CABG outcomes, "especially since there is already an evidence base for recommending these medications," he added.

"What was novel in this study was the ability of adherence to recommended medications to essentially 'cancel out' the relative benefit for CABG over PCI in this patient population," according to Kurlansky.

"This finding, should it be confirmed, might be explained as follows," he said. "Since PCI directly addresses the most diseased portion of the coronary artery in an effort to remodel the atherosclerotic plaque, while CABG brings a conduit downstream to a less diseased area, the long-term success of PCI may be more dependent on the ability of the medications to control the atherosclerotic process. However, although this is an interesting theory, it is merely conjecture at this point."

This study was supported by unrestricted educational grants from the Miami Heart Research Institute and HCA Healthcare. The authors have no relevant financial relationships.

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