Bioabsorbable polymer-coated sirolimus-eluting stent implantation preserves coronary vasomotion: A DESSOLVE II trial sub-study.

OBJECTIVES: We studied coronary vasomotion in patients treated with the Mistent(®) absorbable polymer sirolimus-eluting stent (APSES) and in patients implanted with the Endeavor(®) zotarolimus-eluting stent (ZES). BACKGROUND: First generation (1st-gen) drug-eluting stents (DES) induce persistent vasomotor dysfunction in the treated coronary artery. It is unknown whether and to what extent the implantation of an absorbable polymer DES impairs coronary vasomotion. METHODS: This sub-study of the DESSOLVE II trial included 19 APSES Mistent(®) and 10 ZES Endeavor(®) patients. Incremental atrial pacing and quantitative coronary angiography were used to assess vasomotion proximal and distal to the stent and in a reference segment at 9 months after implantation. Percent changes in vessel diameter with pacing versus baseline were calculated and compared. Vasomotor response of the APSES group was also compared with changes observed in a historical group of 17 patients implanted with a 1st-gen sirolimus-eluting stent (SES). RESULTS: Normal vasomotion (vasodilatation) was preserved and of comparable magnitude in the APSES and in the ZES group both proximally (P = 0.34) and distally (P = 0.38) to the stent. This finding was not observed in the 1st-gen SES group showing marked pacing-induced vasoconstriction at both stent edges (P < 0.05 vs. APSES). The results were practically unchanged after excluding patients with absolute changes in vessel diameter <3% between baseline and maximal pacing. CONCLUSIONS: The implantation of an absorbable polymer sirolimus-eluting stent is associated with preserved coronary vasomotion, comparable to that observed after implantation of the Endeavor(®) ZES, and distinct from 1st-gen SES which induce coronary vasomotor dysfunction.

Impact of platelet glycoprotein IIb/IIIa receptor inhibitors on outcomes of diabetic patients undergoing percutaneous coronary interventions using sirolimus-eluting stents.

OBJECTIVE: We assessed the outcomes in diabetic patients undergoing percutaneous coronary intervention (PCI) using sirolimus-eluting stents (SES) as a function of treatment with glycoprotein (GP) IIb/IIIa inhibitors. METHODS AND RESULTS: Of 551 diabetic patients treated with a SES in nine trials (RAVEL, SIRIUS, E-SIRIUS, C-SIRIUS, REALITY, SVELTE, DIRECT, SIRIUS 2.25, and SIRIUS 4.0), 187 patients (33.9%) were administered GP IIb/IIIa inhibitors during PCI. GP IIb/IIIa blockade was associated with lower rates of myocardial infarction (MI) at 30 days (1.1% vs. 3.3%, P = 0.12) and at 1 year (1.1% vs. 4.7%, P = 0.04), and composite endpoint of cardiac death/MI at 1 year (2.2% vs. 6.2%, P = 0.05). Benefit from GP IIb/IIIa inhibitors was confined to 128 insulin-treated diabetics who had remarkable reduction in MI (0.0% vs. 6.3%, P = 0.04) and cardiac death/MI at 30 days (0.0% vs. 7.6%, P = 0.05) and at 1-year (0.0% vs. 13.4%, P = 0.01 and 0.0% vs. 15.7%, P = 0.0005, respectively). When treated with GP IIb/IIIa inhibitors, insulin-requiring diabetics had similar rates of 1-year death/MI when compared with the nondiabetic patients (0% vs. 4.7%, P = 0.13, respectively). There were no significant differences in outcomes as a function of GP IIb/IIIa blockade in diabetics not treated with insulin. CONCLUSION: In this analysis, outcomes of insulin requiring diabetic patients undergoing PCI with SES were considerably improved with adjunctive GP IIb/IIIa inhibitors by decreasing the rates of MI and composite endpoint of cardiac death/MI.

Evaluation of the MiStent sustained sirolimus eluting biodegradable polymer coated stent for the treatment of coronary artery disease: does uniform sustained abluminal drug release result in earlier strut coverage and better safety profile?

INTRODUCTION: Treatment of coronary artery disease has made strides over the last decades. Development of drug eluting stents (DES), coated with a polymer layer and an anti-proliferative drug to reduce neointimal hyperplasia, has reduced the incidence of in-stent-restenosis relative to treatment with bare metal stents. Patients treated with first generation DES more likely suffer from (very) late events which can be cause by the permanent presence of a polymer. Therefore second generation DES with more biocompatible coatings, and third generation DES, with very thin struts coated with biodegradable polymers, were developed. Areas covered: The MiStent SES is one of these third generation DES and is designed to limit the duration of polymer exposure, optimize coronary vessel healing and more precisely and consistently control drug elution to improve safety and clinical outcomes. This review provides a detailed description of the technique behind the MiStent SES, and describes the pre-clinical and clinical trials conducted with this device to date. Expert commentary: Recent clinical trials have shown non-inferiority of very thin strut biodegradable polymer coated DES compared to durable polymer coated DES, whilst maintaining an excellent safety profile. Longer follow-up, to see the real potential benefits of these devices, is mandatory however.

Relationship of late loss in lumen diameter to coronary restenosis in sirolimus-eluting stents.

BACKGROUND: Observed rates of restenosis after drug-eluting stenting are low (<10%). Identification of a reliable and powerful angiographic end point will be useful in future trials. METHODS AND RESULTS: Late loss (postprocedural minimum lumen diameter minus 8-month minimum lumen diameter) was measured in the angiographic cohorts of the SIRIUS (n=703) and E-SIRIUS (n=308) trials. Two techniques, the standard normal approximation and an optimized power transformation, were used to predict binary angiographic restenosis rates and compare them with observed restenosis rates. The mean in-stent late loss observed in the SIRIUS trial was 0.17+/-0.45 mm (sirolimus) versus 1.00+/-0.70 mm (control). If a normal distribution was assumed, late loss accurately estimated in-stent binary angiographic restenosis for the control arm (predicted 35.4% versus observed 35.4%) but underestimated it in the sirolimus arm (predicted 0.6% versus observed 3.2%). Power transformation improved the reliability of the estimate in the sirolimus arm (predicted 3.2% [CI 1.0% to 6.7%]) with similar improvements in the E-SIRIUS trial (predicted 4.0% [CI 1.2% to 7.0%] versus observed 3.9%). In the sirolimus-eluting stent arm, in-stent late loss correlated better with target-lesion revascularization than in-segment late loss (c-statistic=0.915 versus 0.665). CONCLUSIONS: Because distributions of late loss with a low mean are right-skewed, the use of a transformation improves the accuracy of predicting low binary restenosis rates. Late loss is monotonically correlated with the probability of restenosis and yields a more efficient estimate of the restenosis process in the era of lower binary restenosis rates.

Sirolimus-eluting stents at two years: a pooled analysis of SIRIUS, E-SIRIUS, and C-SIRIUS with emphasis on late revascularizations and stent thromboses.

Prospective follow-up at 2 years was obtained for 98.7% of the pooled 1,510 patients enrolled in SIRIUS, E-SIRIUS and C-SIRIUS, 3 randomized controlled trials that compared sirolimus-eluting stents (SESs) with bare metal stents (BMSs) to treat long stenoses in small coronary arteries. By 720 days, clinically driven target lesion revascularizations were performed in 5.7% of patients with SESs versus 22.6% of patients with BMSs (risk ratio 0.25, 95% confidence interval 0.18 to 0.35, p <0.001). Of these, late target lesion revascularization (from 271 to 720 days) was performed in 12 patients who received SESs (1.6%) compared with 37 patients with BMSs (4.9%) (risk ratio 0.32, 0.17 to 0.61, p <0.001). Stent thromboses occurred in 7 of 758 patients with SESs (0.9%, 4 subacute, 3 late) and 5 of 752 patients with BMSs (0.7%, 1 subacute, 4 late) (risk ratio 1.39, 95% confidence interval 0.44 to 4.36, p = 0.774). The Kaplan-Meier estimate of freedom from major cardiac adverse events was 89.3% for patients with SESs versus 73.4% for patients with BMSs (p <0.001). This analysis demonstrates the sustained efficacy and safety of sirolimus-eluting stents at 2 years, characterized by a persistent significant benefit in freedom from repeat revascularization compared with BMSs and a low risk of late stent thrombosis, not different from BMSs.

Technical overview on the MiStent coronary stent.

Drug-eluting stents (DES) have dramatically improved the long-term efficacy of percutaneous coronary intervention (PCI). Over the last decade there have been numerous advances in DES platforms, however, all but one currently approved DES in the United States and many of the approved DES worldwide still have 3 common features: a metal stent platform, an anti-proliferative drug, and a permanent polymer. In this context, the polymer is critical to control drug release, but the polymer serves no purpose after the drug is eluted. While designed to be completely biocompatible, synthetic polymers have the potential to illicit an inflammatory response within the vessel including but not limited to delayed healing and hypersensitivity. Adverse vascular reactions to these polymers have been implicated as a cause of very late stent thrombosis, ongoing intimal hyperplasia and late "catch-up" in addition to neoatherosclerosis. To avoid the long-term risks associated with prolonged polymer exposure, DES with bioabsorbable polymers have been developed. The MiStent® Sirolimus-Eluting Absorbable Polymer Coronary Stent System (MiStent SES) (MiCell Technologies, Durham, NC, USA) combines crystalline sirolimus, a rapidly absorbing polylactide-co-glycolic acid (PLGA) coating and a thin-strut cobalt chromium alloy stent platform (Genius MAGIC® Stent System, EuroCor GmbH, Germany). MiCell's supercritical fluid technology allows a rigorously controlled, solvent-free drug and polymer coating to be applied to a bare-metal stent. This solvent-free application of drug uniquely allows a crystalline form of sirolimus to be used on the MiStent SES potentially providing improved clinical benefits. It avoids the uncontrolled burst of drug seen with other DES, provides uniform drug delivery around and between the stent struts, and allows the anti-inflammatory and anti-restenotic drug (sirolimus) to be present in the tissue through the entire polymer absorption period and for months after the polymer has been absorbed. On the MiStent SES, the PLGA/crystalline sirolimus combination is cleared from the stent within 45-60 days and PLGA is fully absorbed within 90 days. The crystalline form of sirolimus uniquely remains in the tissue and continues to expose the surrounding tissue to therapeutic levels of drug for up to 9 months which is long after the polymer is resorbed.

The clinical outcome of percutaneous treatment of bifurcation lesions in multivessel coronary artery disease with the sirolimus-eluting stent: insights from the Arterial Revascularization Therapies Study part II (ARTS II).

AIMS: Little is known about the impact of treating bifurcations on the overall outcome of multivessel coronary artery disease treated with stenting. This analysis was made to investigate the 1 year clinical outcome of the treatment of bifurcation lesions using sirolimus-eluting stents (SES) in patients with multivessel disease. METHODS AND RESULTS: Among a total of 607 patients (2160 lesions) in the Arterial Revascularization Therapies Study part II (ARTS II), there were 324 patients in whom at least one bifurcation lesion was treated (465 lesions). Patients with bifurcations were compared with those without bifurcations in terms of baseline characteristics and major adverse cardiac and cerebrovascular events (MACCE). Patients with 'true' (200 patients) vs. 'partial' bifurcations (124 patients) and usage of a one- (263 patients) vs. two-stent strategy (61 patients) were also evaluated. The bifurcation group was associated with more complex lesion and procedural characteristics than the non-bifurcation group. However, there was no significant difference in 1 year MACCE rates between the bifurcation group and the non-bifurcation group (13.3 vs. 11.0%, P=0.46). MACCE in patients with true bifurcations was 13.0 vs. 13.7% for partial bifurcations (P=0.87) and 14.1 vs. 9.8% for one- vs. two-stent strategy (P=0.53). CONCLUSIONS: In this trial without angiographic follow-up, the presence of bifurcations did not affect 1 year outcomes after SES implantation. The outcomes in true vs. partial bifurcations and using one vs. two stents were similar when the treatment strategies were left to the operator's discretion.

Periprocedural and late consequences of overlapping Cypher sirolimus-eluting stents: pooled analysis of five clinical trials.

OBJECTIVES: The purpose of this research was to determine the relative safety and efficacy of multiple (> or =2) overlapping Cypher sirolimus-eluting stents (SES) (Johnson & Johnson, New Brunswick, New Jersey). BACKGROUND: Overlapping coronary stents are common. The periprocedural and late clinical and angiographic consequences of overlapped coronary stents are not clearly defined, particularly for drug-eluting stents. METHODS: All patients enrolled into five clinical trials of the SES were analyzed. Three of these trials were prospective randomized comparisons of the SES to the bare-metal stent (BMS), and two were prospective non-randomized trials of SES-treated patients with historical controls. All clinical and angiographic outcomes in overlap-stent-treated patients were compared by stent type and with single-stent-treated patients for the same stent device. RESULTS: In all, 575 patients with stent overlap (337 SES, 238 BMS) and 1,162 patients with single stents (697 SES, 465 BMS) were analyzed. Stent overlap was associated with a greater late lumen loss in stent and more frequent angiographic restenosis regardless of stent type. Among overlap-stent-treated patients, the SES provided similar magnitude of restenosis benefit as observed for single-stent-treated patients. Overlapped SES was not associated with an increase in myocardial infarction. CONCLUSIONS: The strategy of SES overlap, when required, is both safe and efficacious in reducing restenosis with no increase in the incidence of myocardial infarction or major adverse cardiovascular events, when compared with a bare metal coronary stent prosthesis.