Patients with unprotected left main disease (ULMD) who were treated with everolimus-eluting stents (EES, Xience, Abbott Vascular) experienced significantly fewer major adverse cardiovascular events (MACE) at the one-year mark than ULMD patients who received paclitaxel-eluting stents (PES, Taxus, Boston Scientific), according to a study published Oct. 2 in the Journal of the American College of Cardiology.
Renato Valenti, MD, of the division of cardiology at Careggi Hospital in Florence, Italy, and colleagues suggested that if ULMD patients receive the newer EES, PCI may lead to more successful outcomes than had been suggested in SYNTAX (Synergy Between PCI with Taxus and Cardiac Surgery (N Engl J Med 2009; 360:961-972). The authors noted that ULMD patients in the SYNTAX study who underwent PCI received first-generation PES.
The SYNTAX study compared the results of CABG with PCI performed between 2005 and 2007 in 2,700 patients with three-vessel or ULMD. Results showed that at 12 months, the rates of major adverse cardiac or cerebrovascular events were significantly higher in the PCI group than the CABG group (17.8 vs. 12.4 percent). PCI patients had higher rates of revascularization, as 13.5 percent of patients in the PCI group underwent repeat revascularization compared with 5.9 percent in the CABG group.
Death rates at 12 months were 5 percent in the CABG group vs. 4.4 percent in the PCI group. Based on these findings, CABG has remained the standard of care for patients who were surgical candidates.
Noting that randomized studies have shown the superiority of EES over PES in non-left main coronary artery disease but that no data existed regarding the stents’ relative effectiveness in ULMD, the authors of the current study compared outcomes for 390 patients enrolled in the ULMD registry in Florence who underwent PCI between 2004 and 2010. The primary endpoint of the study was the 12-month MACE; secondary endpoints were target vessel failure (TVF) and in-segment left main restenosis.
Due to “broader indication to PCI in the last years,” the authors expected differences in baseline characteristics of the two groups of patients. The PES group had a higher incidence of hypercholesterolemia, peripheral vascular disease and renal insufficiency compared with the EES patients. Distal ULMD was more prevalent among the patients who received EES. The authors conducted a propensity score matching analysis to adjust for the differences.
At the 12 month post-PCI follow-up point, MACE incidence was 21.9 percent among the PES group and 10.2 percent among the EES group. The authors stated that the difference in MACE was attributable primarily to the significantly lower target vessel revascularization rate in the EES group (4.2 percent compared to 13.4 percent in the PES group). The long-term event-free survival rate was 84 percent among the EES patients and 68 percent among the PES patients.
The authors pointed out that their findings comport with other studies that have demonstrated the superiority of EES compared with PES, but with more dramatic results.
“It is likely that in the subset of patients with ULMD, where the target lesion in the majority of cases involves a bifurcation or a trifurcation and is associated with multivessel disease requiring multivessel intervention, the benefit provided by EES as compared with PES may be increased as compared with the benefit shown in randomized trials that included patients with lesions at lower risk of TVF,” they wrote. “The relevant reduction of clinical events with EES results in a better clinical outcome as compared with the ULMD PCI and surgical cohorts of the SYNTAX trial.”
Among the study's limitations, they noted that it was non-randomized, involved only one center and relied on registry data.