Differential outcomes after sirolimus-eluting stent implantation: comparing on-label versus off-label patients in the ‘real world’

BackgroundRandomized controlled trials indicate that sirolimus-eluting stents (SES) reduce the rates of restenosis and need for subsequent revascularization procedures, but patients enrolled in randomized trials represent a highly selected population. This study examined the performance of SES in a ‘real world’ setting by comparing the outcomes of trial-eligible versus ineligible patients undergoing percutaneous coronary intervention. MethodsFrom the US commercial introduction of SES in April 2003 until December 2003, all patients that received an SES at our institution were followed in a prospective registry (n=838). For the purpose of this analysis, the registry population was divided into two groups based on the inclusion and exclusion criteria of the stenosis in a native coronary artery (SIRIUS) trial. The primary endpoint of the study was the rate of target lesion revascularization (TLR) at follow-up. Secondary endpoints included major adverse cardiac events (MACE) such as cardiac death, myocardial infarction, and target vessel revascularization. Clinical follow-up was complete for 92% of patients with a median duration of 14.2 months. ResultsOverall, 296 patients (35.3%) met entry criteria for the SIRIUS trial and thus comprised the SIRIUS eligible group. Patients in the SIRIUS ineligible group (n=542) were more likely to have chronic kidney disease and earlier bypass surgery and had longer mean stent length. At 1 year, TLR occurred in 3.0% of the SIRIUS eligible population and in 9.2% of the SIRIUS ineligible group (P=0.001). The secondary endpoint of cumulative MACE occurred in 6.6% of the SIRIUS eligible versus in 17.7% of the SIRIUS ineligible population (P<0.001). Two patients (0.4%) in the SIRIUS ineligible group had a late stent thrombosis on days 39 and 99, respectively, versus none in the SIRIUS eligible group. ConclusionAmong ‘real world’ patients treated with SES, the incidence of TLR and MACE at 1 year was substantially greater among SIRIUS ineligible patients compared with SIRIUS eligible patients. These findings confirm that pivotal clinical trials of drug-eluting stents tend to enroll low-risk patients and that the estimated rates of TLR and MACE derived from such trials may not reflect subsequent outcomes with unrestricted clinical use.