Safety and efficacy of 2.5-mm sirolimus-eluting stent implantation at lower deployment pressures in very small vessels (<2.5 mm)

Intravascular ultrasound analysis of small vessel lesions treated with the Sparrow coronary stent system: results of the CARE II trial

OBJECTIVES

The aim of this study was to evaluate the Sparrow sirolimus-eluting stent (Sparrow-SES) against the Sparrow bare-metal stent (Sparrow-BMS) and conventional balloon-expandable bare-metal stent (BMS: Driver/Micro-Driver stent, Medtronic Vascular, Santa Rosa, CA).

BACKGROUND

The Sparrow stent (Biosensors International, Singapore) consists of a guide wire-based, self-expandable, ultra-thin nitinol stent. The performance of this device with sirolimus in a fully biodegradable polymer has not been determined.

METHODS

A total of 74 patients were included in this intravascular ultrasound (IVUS) sub-study of the CARE II trial, which was a prospective, randomized, multicenter trial in the treatment of single de novo native coronary artery lesions in vessels ranging from 2.0 mm to 2.75 mm in diameter (Sparrow-SES: n = 31, Sparrow-BMS: n = 22, BMS: n = 21).

RESULTS

Stent volume index (VI) was significantly increased 8-month later in Sparrow-SES and Sparrow-BMS, but not in BMS (4.0 ± 1.0 to 4.6 ± 1.0 mm(3) /mm, p<0.0001, 4.0 ± 0.6 to 4.4 ± 0.8 mm(3) /mm, p<0.05, and 5.2 ± 1.0 to 5.1 ± 0.9 mm(3) /mm, p=0.421, respectively). % neointimal obstruction in Sparrow-SES was significantly smaller than those in Sparrow-BMS and BMS at follow-up (17.6 ± 9.4 vs. 36.2 ± 13.8 and 39.9 ± 11.1%, p<0.001). Sparrow-SES showed a mean 15% stent expansion and good suppression of neointimal proliferation, resulting in a significantly lower percentage of change in lumen VI during follow-up period (Sparrow-SES: -6.2 ± 16.2%, Sparrow-BMS: -30.4 ± 11.6%, BMS: -40.4 ± 10.0%, p<0.001).

CONCLUSIONS

The self-expanding Sparrow-SES demonstrated chronic stent expansion, good suppression of neointimal proliferation and resulted in a more preserved lumen in stented small vessels compared with the Sparrow-BMS and conventional balloon expandable BMS.

In-stent restenosis is inhibited in a bare metal stent implanted distal to a sirolimus-eluting stent to treat a long de novo coronary lesion with small distal vessel diameter

OBJECTIVES

This study examined whether sirolimus-eluting stent (SES) implantation exerts an antiproliferative action on a bare metal stent (BMS) placed distally in the same coronary artery.

BACKGROUND

Diffusion of sirolimus into flowing coronary blood may cause accumulation of this drug in the coronary bed beyond the distal edge of an SES.

METHODS

We analyzed data from 115 consecutive patients with ischemic heart disease who were treated with two overlapping stents without a gap in the same coronary artery for a long de novo lesion. The distal stent was a 2.25 mm BMS in all patients, and the proximal stent was an SES in 73 patients (SES-BMS group) and a BMS in 42 patients (BMS-BMS group). Quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) were performed at stent implantation and 8 months later.

RESULTS

Clinical and procedural variables were comparable between the two groups. QCA and IVUS showed that the SES-BMS group had less luminal late loss and a lower percent of in-stent volume obstruction in the distal BMS compared with the BMS-BMS group. Furthermore, compared with the BMS-BMS group, the SES-BMS group had less in-stent restenosis (23.3 vs. 54.8%, P < 0.0005) and target lesion revascularization (21.9 vs. 50.0%, P < 0.005).

CONCLUSIONS

SES implantation just proximal to a BMS inhibits neointimal proliferation in the BMS, when both stents are implanted in the same coronary artery to treat a de novo lesion.

One-year outcome of small-vessel disease treated with sirolimus-eluting stents: a subgroup analysis of the e-SELECT registry

OBJECTIVES

To investigate the characteristics and one-year outcomes following sirolimus-eluting CYPHER Select Plus stent (SES) implantation in small (SmVD) and non-small vessel disease (NSmVD) in the international e-SELECT registry.

BACKGROUND

Large-scale registry data are lacking on DES outcomes in SmVD treatment.

METHODS

There were 4,700 SmVD (at least one vessel with estimated reference vessel diameter [RVD] < 2.5 mm, excluding 283 patients with unknown RVD vessels) and 10,139 NSmVD only patients.

RESULTS

The SmVD population was older, with more women, diabetics, and vessels treated, higher mean Charlson Comorbidity Index score (CCI), shorter lesions, and less STEMI presentation. The 1-year stent thrombosis (ST) rate (primary end-point), was significantly higher (1.3% vs. 0.7%) in SmVD versus NSmVD, mainly driven by early events. One-year major adverse cardiac event (MACE), myocardial infarction (MI), and clinically indicated target-lesion revascularization (TLR) rates were significantly higher in SmVD although death and major bleeding rates were similar in both groups. Complication rates were similar between pure (3,188 patients; only RVD < 2.5 mm) and mixed (1,795 patients; some RVD < 2.5 mm or unknown RVD) SmVD. Multivariate predictors for 1-year MACE in SmVD included saphenous vein graft or bifurcation lesions, major bleeding, any antiplatelet therapy discontinuation within 1 month, age, number of stents implanted, CCI, acute coronary syndrome, and insulin-dependent diabetes mellitus.

CONCLUSION

SES implantation for SmVD occurs more frequently in women, diabetics, and those with multivessel disease and comorbidities. One-year ST, MACE, MI, and clinically indicated TLR rates are higher, although low overall, in SmVD or mixed SmVD patients while death rates are similar to NSmVD.

Drug-eluting stents perform better than bare metal stents in small coronary vessels: a meta-analysis of randomised and observational clinical studies with mid-term follow up

BACKGROUND

We tested drug-eluting stent (DES) and bare metal stent (BMS) performance in small coronary vessels by means of meta-analysis of all available clinical studies.

METHODS

The analysis included randomised controlled trials (RCT), subgroups of RCT and observational studies with a follow-up of at least six months comparing the use of DES and BMS during percutaneous interventions involving small coronary arteries (diameter<3mm). The primary endpoint was target vessel failure (TVF); the others were pooled and isolated major adverse cardiovascular events (MACE), stent thrombosis (ST), binary restenosis and late lumen loss at the longest available follow-up. The effect of treatment was evaluated in terms of odds ratios (OR) and 95% confidence intervals (95% CI) for binary variables, and mean difference (MD)± standard deviation (SD) for continuous variables. Fixed- or random-effect models were used depending on the statistical heterogeneity of studies. The analyses of major endpoints were stratified by study type, length of follow-up, and type of DES.

RESULTS

We pooled 12 studies involving 3182 patients. Trial heterogeneity was a minor issue. TVF (OR: 0.35; CI: 0.24-0.51), MACE (OR: 0.36; CI: 0.29-0.45), binary restenosis (OR: 0.15; CI: 0.12-0.20) and late lumen loss (MD: -0.46; SD: -0.55 to -0.38) all significantly improved with DES treatment; ST (OR: 0.63; CI: 0.34-1.17) was not statistically different between studies.

CONCLUSIONS

DES are superior to BMS in terms of their efficacy in managing small coronary arteries (diameter<3mm), and at least equivalent in terms of safety. The use of DES should be considered the treatment of choice in this setting.