Stent placement for non-STRESS/BENESTENT lesions: a critical review

Outcomes with drug-coated balloons vs. drug-eluting stents in small-vessel coronary artery disease

BACKGROUND

The use of drug-coated balloons (DCBs) in small-vessel coronary artery disease (SVD) remains controversial.

METHODS

We performed a meta-analysis of all randomized controlled trials (RCTs) reporting the outcomes of DCB vs. DES in de-novo SVD. We included a total of 5 RCTs (1459 patients), with (DCB n = 734 and DES n = 725).

RESULTS

Over a median follow-up duration of 6 months, DCB was associated with smaller late lumen loss (LLL) compared with DES (mean difference -0.12 mm) (95% confidence intervals (CI) [-0.21, -0.03 mm], p = 0.01). Over a median follow-up of 12 months, both modalities had similar risk of major adverse cardiovascular events (MACE) (8.7% vs. 10.2%; odds ratio (OR): 0.94, 95% CI [0.49-1.79], p = 084), all-cause mortality (1.17% vs. 2.38%; OR: 0.53, 95% CI [0.16-1.75], p = 0.30), target lesion revascularization (TLR) (7.9% vs. 3.9%; OR: 1.26, 95% CI [0.51-3.14], p = 0.62), and target vessel revascularization (TVR) (8.2% vs. 7.8%; OR: 1.06, 95% CI [0.40-2.82], p = 0.91). DCBs were associated with lower risk of myocardial infarction (MI) compared with DES (1.55% vs. 3.31%; OR: 0.48, 95% CI [0.23-1.00], p = 0.05, I2 = 0%).

CONCLUSION

PCI of SVD with DCBs is associated with smaller LLL, lower risk of MI, and similar risk of MACE, death, TLR, and TVR compared with DES over one year. DCB appears as an attractive alternative to DES in patients with de-novo SVD, but long-term clinical data are still needed.

Applied pharmacology in percutaneous coronary intervention: You can't fight mother nature

Differential outcomes based on target vessel diameter persist in the era of second generation drug eluting stents. These differences are mainly driven by need for target vessel revascularization without appreciable differences in hard atherosclerotic cardiovascular disease outcomes that is, mortality and myocardial infarction. Future non mechanistic treatment options based on patient characteristics maybe needed.

Drug-coated Balloons for Small Coronary Vessel Interventions: A Literature Review

Newer-generation drug-eluting stents (DES) are the standard of care for the treatment of symptomatic coronary artery disease. However, some lack of efficacy has been reported in small coronary arteries based on higher rates of target lesion restenosis, thrombosis and MI resulting in repeated interventions. Drug-coated balloons (DCBs) are an established treatment option for in-stent restenosis in both bare metal stents and DES and they can deliver an anti-proliferative drug into the vessel wall without implanting a stent. DCBs are a promising technique for selected de novo coronary lesions, especially in small vessel disease. In this article, the current evidence for the treatment of small vessel disease with DCBs will be reviewed.

Role of Drug-coated Balloons in Small-vessel Coronary Artery Disease

Percutaneous coronary intervention of small-vessel coronary artery disease (SVD) remains challenging due to difficulties with device delivery and high restenosis rate, even with the use of newer-generation drug-eluting stents. Drug-coated balloons represent an attractive emerging percutaneous coronary intervention option in patients with SVD. Potential advantages of drug-coated balloons in SVD include enhanced deliverability because of their small profile, avoidance of foreign-body implantation, and shorter duration of dual antiplatelet therapy.

Miniaturized self-expanding drug-eluting stent in small coronary arteries: late effectiveness

Background

Small vessels represent a risk factor for restenosis in percutaneous coronary angioplasty (PCA). The Sparrow^® self-expanding drug-eluting stent, which has a lower profile than the current systems, has never been tested in this scenario.

Objectives

To evaluate the late effectiveness of the Sparrow^® drug-eluting stent, regarding in-stent late lumen loss (LLL).

Methods

Patients with ischemia, symptomatic or documented, were submitted to PCA in vessels with reference diameter < 2.75 mm, divided into two groups regarding Sparrow^® stent type: group 1: Sparrow^® drug-eluting stent (DES), group 2: Sparrow^® bare metal stent (BMS). Clinical follow-up duration was 12 months. Evaluation using quantitative coronary angiography (QCA) was performed immediately and at 8 months. A decrease of over 65% of in-stent LLL with DES was estimated to calculate sample size. IBM^® SPSS software, release 19 (Chicago, Illinois, USA) was used for the statistical analysis.

Results

A total of 24 patients were randomized, 12 in each group. The DES and BMS groups were similar in age (63.25 ± 10.01 vs. 64.58 ± 11.54, p = 0.765), male gender (58.3% vs. 33.3%, p = 0.412), risk factors and all angiographs aspects. Immediate results were satisfactory in both groups. At 8 months in-stent late lumen loss was significantly lower in DES than in BMS group (DES vs. BMS 0.25 ± 0.16 0.97 ± 0.76, p = 0.008).

Conclusion

In small-vessel PCA, the Sparrow^® DES determined significant reduction in in-stent LLL, when compared to Sparrow^® BMS.

New technologies aimed at percutaneous intervention in the small coronary artery

Percutaneous coronary intervention (PCI) of small vessels can be complicated by technically difficult access to the target lesion, an increased risk of major adverse cardiac events and in-stent restenosis requiring repeat revascularization. Conventional management of such lesions is with drug-eluting stent implantation; however, these have only partly attenuated the problem. In response, several medical device companies are competing to produce new technologies aimed at PCI in small coronary arteries. Such innovations include thin-strutted stents, stent-on-a-wire systems, drug-coated balloons, endothelial progenitor cell-catching stents and biodegradable stent systems. To date, none of these techniques have been sufficiently validated for use in small coronary arteries to justify a change in practice; however, small-vessel coronary artery disease is an increasingly common problem, and PCI of target lesions with reference vessel diameter <3.0 mm is likely to increase, especially in view of the increasing prevalence of diabetes, warranting further well-designed studies. The prospect of mounting a self-expandable biodegradable drug-eluting stent directly onto a guidewire could potentially be an exciting future development.

Small coronary vessel angioplasty: outcomes and technical considerations

Small vessel (<3 mm) coronary artery disease is common and has been identified as independent predictor of restenosis after percutaneous coronary intervention. It remains controversial whether bare-metal stent (BMS) implantation in small vessels has an advantage over balloon angioplasty in terms of angiographic and clinical outcomes. Introduction of drug-eluting stent (DES) has resulted in significant reduction in restenosis and the need for repeat revascularization. Several DESs have been introduced resulting in varying reduction in outcomes as compared with BMS. However, their impact on outcomes in small vessels is not clearly known. It is expected that DES could substantially reduce restenosis in smaller vessels. Large, randomized studies are warranted to assess the impact of different DESs on outcomes in patients with small coronary arteries.

Thin strut chrome-cobalt stent implantation for treatment of de-novo lesions in small coronary vessels: results of the RISICO Italian Registry (Registro Italiano Mini VISION nei piccolo Vasi) utilizing the Mini VISION coronary stent platform

OBJECTIVES

The Registro Italiano Mini VISION nei piccoli Vasi registry is a prospective, multicenter, observational study, aimed at assessing immediate and long-term angiographic and clinical outcomes of a small-vessel cobalt-chrome super alloy-dedicated stent (Multi-Link RX VISION) in de-novo and long lesions.

BACKGROUND

Small artery size is an important determinant of poor outcomes in percutaneous coronary interventions.

METHODS

Patients with ischemic heart disease were included. The primary end point was procedural success. Secondary end points included clinical restenosis (need for target lesion revascularization ), incidence of major adverse cardiac events at 6 months, and cost-effectiveness analysis.

RESULTS

Between September 2004 and October 2005, 143 patients (mean age 67 +/- 11 years; 22% diabetes) were enrolled; 6-month follow-up was completed in May 2006. Average lesion length, mean stent length and diameter were 16.8 +/- 7.1, 17.01 +/- 3.9 and 2.41 +/- 0.14 mm, respectively. Procedural success was 96%. At 6-month follow-up, the hierarchical major adverse cardiac event rate was 11.6%, 2.9% deaths, 2.9% myocardial infarction and 5.8% target lesion revascularization. Cost-effectiveness analysis will be reported in a further publication.

CONCLUSION

Small-vessel disease treatment with Mini VISION stents permits an elevated procedural success rate with low incidence of clinical restenosis and major adverse cardiac events at mid-term follow-up. Such results require confirmation by means of a randomized controlled study against drug-eluting stents.

New stent design for use in small coronary arteries during percutaneous coronary intervention

Patients with diabetes mellitus, of female gender, increased age, and/or with peripheral vascular disease often develop coronary stenoses in small caliber vessels. This review describes treatment of these lesions with the paclitaxel-eluting 2.25 mm TAXUS^® Liberté^® Atom™ stent. Given the same stent composition, polymer, antirestenotic drug (paclitaxel), and release kinetics as the first-generation 2.25 mm TAXUS^® Express^® Atom™ stent, the second-generation TAXUS Liberté Atom stent incorporates improved stent design characteristics, including thinner struts (0.0038 versus 0.0052 inches), intended to increase conformability and deliverability. In a porcine noninjured coronary artery model, TAXUS Liberté Atom stent implantation in small vessels demonstrated complete strut tissue coverage compared with the bare metal stent control, suggesting a similar degree of tissue healing between the groups at 30, 90, and 180 days. The prospective, single-armed TAXUS ATLAS Small Vessel trial demonstrated improved instent late loss (0.28 ± 0.45 versus 0.84 ± 0.57 mm, P < 0.001), instent binary restenosis (13.0% versus 38.1%, P < 0.001), and target lesion revascularization (5.8% versus 17.6%, P < 0.001) at nine months with the TAXUS Liberté Atom stent as compared with the bare metal Express stent control, with similar safety measures between the two groups. The TAXUS Liberté Atom also significantly reduced nine-month angiographic rates of both instent late loss (0.28 ± 0.45 versus 0.44 ± 0.61 mm, P = 0.03) and instent binary restenosis (13.0% versus 25.9%, P = 0.02) when compared with the 2.25 mm TAXUS Express Atom control. The observed reduction in target lesion revascularization with the TAXUS Liberté Atom compared with the TAXUS Express Atom at nine months (5.8% versus 13.7%, P = 0.02) was sustained through three years (10.0% versus 22.1%, P = 0.008) with similar, stable safety outcomes between the groups. In conclusion, these data confirm the safety and favorable performance of the TAXUS Liberté Atom stent in the treatment of small coronary vessels.

Clinical and angiographic follow-up of small vessel lesions treated with paclitaxel-eluting stents (from the TRUE Registry)

Several randomized trials have shown that sirolimus-eluting stents and paclitaxel-eluting stents (PES) are effective in reducing restenosis in respect to bare-metal stents, including the subset of small vessels. The objective of this study was to evaluate "real world" angiographic and clinical outcomes of a large series of patients enrolled in the TRUE registry and treated with PES for both small vessel and very small vessel lesions. A consecutive series of 675 patients (926 lesions) with reference vessel diameter <2.75 mm measured by quantitative coronary angiography analysis were analyzed. The primary end point was the rate of angiographic in-stent restenosis and 1-year major adverse cardiac events. In this study 390 lesions were identified as small vessel (reference vessel diameter >or=2.25 and <2.75 mm) and 536 lesions as very small vessel (reference vessel diameter <2.25 mm). Overall in-stent restenosis was 15.5% (n = 96). Compared with small vessel, the very small vessel lesions had more in-stent restenosis (21.7% vs 11.4%, p <0.001) and in-segment restenosis (29.3% vs 22.5%, p = 0.055). The majority of the restenotic lesions (n = 125) were focal (57%, n = 71). At 1 year, cardiac death was 1.6% (n = 11), acute myocardial infarction 0.5% (n = 4.), and the target lesion revascularization 12.8% (n = 86). Cumulative major adverse cardiac events rate was 17.3% (n = 119). The rate of definite and probable stent thrombosis was 0.9% (n = 8). In conclusion, in comparison with historical bare-metal stent controls, this large series of small vessel lesions treated with PES confirms previous results reporting the efficacy of PES in small vessels. The rate of subacute and late stent thrombosis was low in this subgroup of patients.

Two-year clinical outcome after coronary stenting of small vessels using 2.25-mm sirolimus- and paclitaxel-eluting stents: Insight into the RESEARCH and T-SEARCH registries

OBJECTIVES

To evaluate long-term outcomes after drug-eluting stents (DES) implantation in small coronary vessels.

BACKGROUND

Sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) have been reported to improve both the angiographic and clinical outcomes compared with bare metal stents even in 'real world' settings. Currently, no data is available on long-term outcomes after DES implantation in small vessels.

METHODS

Since April 2002, our institution has implanted DES, either SES or PES, as a default strategy in all patients irrespective of their clinical presentation. Between October 2002 and September 2003, 197 consecutive patients were enrolled: 107 consecutive patients received at least one 2.25-mm SES (SES group) and 90 consecutive patients received at least one 2.25-mm PES (PES group).

RESULTS

The two cohorts presented with high-risk characteristics. At 2 years, the cumulative incidence of major adverse cardiac events (MACE) in the SES group was significantly lower than that in the PES group (10.3% vs. 23.3%, P=0.02). There were two subacute angiographic stent thromboses in the PES group and none in the SES group. By multivariate analysis, PES utilization (HR 2.37, 95% CI 1.07-5.26), presentation with acute coronary syndromes (ACS) (HR 3.34, 95% CI 1.44-7.70) and multi-vessel disease (MVD) (HR 3.91, 95% CI 1.27-12.0) were identified as independent predictors of MACE.

CONCLUSIONS

In an unselected population treated for small vessel disease, SES were associated with significantly better 2-year clinical outcomes than PES. The use of PES and the presentation with ACS and MVD were identified as independent predictors of MACE.

Treatment of unprotected left main coronary artery stenosis with a drug eluting stent in a heart transplant patient with allograft vasculopathy

High risk angioplasty with drug eluting stent placement into an unprotected left main coronary artery in a heart transplant recipient with allograft vasculopathy is reported. Ten month angiographic follow up is reported. The literature is reviewed and current methods of revascularisation are described in detail. This is the first report of drug eluting stent use in this clinical situation.

Is bare-metal stenting superior to balloon angioplasty for small vessel coronary artery disease? Evidence from a meta-analysis of randomized trials

AIMS

To compare, by meta-analytical techniques, the clinical impact of bare-metal stenting vs. balloon angioplasty for the treatment of lesions in small coronary arteries.

METHODS AND RESULTS

We included trials with random allocation and prospective comparison of angioplasty vs. stenting, reference vessel diameter<3 mm, and follow-up>or=6 months. Random effect odds ratios (OR) for death, myocardial infarction (MI), repeat revascularization (RR), and major adverse cardiac events (MACEs) were computed. In a pre-specified subgroup analysis, we compared stenting with optimal (post-procedural stenosis<20%) and suboptimal (>20%) angioplasty. Thirteen studies (4383 patients) were selected. No differences were found in terms of death and MI, while MACEs, mainly driven by RR, were significantly less common after stenting (17.6%) than after angioplasty (22.7%), OR 0.71 (0.57-0.90). Heterogeneity among trials was present. When considering only optimal angioplasty, MACE rates were homogeneously similar, 17.9 vs. 21.1%, OR 0.86 (0.66-1.11). If angioplasty were suboptimal, MACEs were significantly more common after angioplasty (24%) than after stenting (17.3%), OR 0.62 (0.44-0.88).

CONCLUSION

Stenting is superior to balloon angioplasty for the treatment of small vessels, in particular after suboptimal angioplasty. However, MACE and RR rates remain high after stenting, and the advantage of stent over angioplasty is moderate. An optimal balloon angioplasty strategy (with provisional stenting) may achieve results not inferior to routine stenting.

Chronic stent recoil plays an important role in restenosis of the right coronary ostium

OBJECTIVE

The efficacy of coronary stenting of aorto-ostial atherosclerotic lesions is still unclear. We investigated the frequency and mechanism of stent restenosis at this particular lesion.

METHODS

Fifty-five consecutive patients with 64 native aorto-ostial lesions in the right coronary artery (RCA, n = 38) and the left main trunk (LM, n = 26) were treated by conventional stenting. Determinants of angiographic restenosis were established. The mechanism of stent restenosis was evaluated using post-stenting and follow-up intravascular ultrasound (IVUS) findings.

RESULTS

Restenosis was more frequent in the RCA than in the LM (50% compared with 19%, P < 0.03) and determinants included diabetes mellitus (63% compared with 21%, P < 0.03), calcium deposition (58% compared with 5%, P < 0.003), smaller stent cross-sectional area (SA) (as demonstrated by post-stenting IVUS studies, 8.1 +/- 1.4 mm compared with 10.2 +/- 2.2 mm, P < 0.01), larger plaque burden (64 +/- 6% compared with 57 +/- 8%, P < 0.03) and less circular expansion at the aorto-coronary junction. Serial IVUS examination was performed in 11 patients with restenosis of the right coronary ostium. The mean reduction in the SA was 21% at the aorto-coronary junction (6.4 +/- 1.9 mm, P < 0.003), whereas the SA at the distal edge was unchanged. Thirty-three per cent of late luminal loss was due to chronic stent recoil.

CONCLUSION

These findings suggest that stenosis of the right coronary ostium is a high-risk lesion for stent restenosis. In addition to excessive intimal growth, chronic stent recoil might be an important etiologic factor at this particular location.

Impact of intracoronary radiation on in-stent restenosis involving ostial lesions

The aim of this study was to compare 6-month clinical outcomes of patients with in-stent restenosis (ISR) involving the ostium treated with intracoronary radiation therapy (IRT) compared to placebo therapy, and also to nonostial lesions treated with IRT. Coronary interventions in ostial lesions have a high rate of recurrence of restenosis. The impact of IRT on ostial ISR has been inadequately characterized. We assessed patients enrolled in gamma (192-iridium) and beta (90-yttrium, 32-phosphorus) radiation trials for ISR at the Washington Hospital Center. Of patients receiving IRT, 105 (8%) patients had ostial ISR and 1,289 (92%) patients had nonostial ISR. Twenty-seven patients had ostial ISR and received placebo therapy. Baseline demographic and angiographic and procedural details were similar, except ostial IRT patients had a trend toward shorter lesions (15.4 +/- 10.8 vs. 24.1 +/- 12.2 mm; P < 0.001) and had a higher rate of saphenous vein graft disease (46% vs. 19%; P < 0.001) compared to nonostial IRT patients. At 6 months, ostial lesions treated with IRT for ISR had a reduced rate of target lesion revascularization (TLR) compared to ostial lesions treated with placebo (15% vs. 43%; P = 0.004). Outcomes at 6 months were similar for the ostial and nonostial IRT groups including TLR (15% vs. 14%; P = 0.80) and composite major adverse cardiac events (18% vs. 15%; P = 0.46). Intracoronary radiation therapy is effective for ostial in-stent restenotic lesions and should be comfortably used for this challenging anatomic location.

Heparin-coated versus uncoated Palmaz-Schatz stent in native coronary circulation. A randomized study with blind angioscopic assessment

The increasing use of stenting to treat more complex lesions and highly thrombogenic situations still carries higher risk for subacute stent thrombosis. To assess new heparin-coated stents in a more stringent reality, 40 consecutive patients were randomized in 1:1 ratio to receive either heparin-coated (group 1, 25 stents) or uncoated Palmaz-Schatz stents (group 2, 32 stents). The two groups were similar in baseline clinical, pre-and post-procedural angiographic and angioscopic characteristics. High pressure stent deployment without intravascular ultrasound guidance was used. All pts received antiplatelet agents alone. We applied serial angioscopy (baseline and on 7th day) to evaluate thrombus formation and quantitative coronary angiography (QCA) to define late (6 months, n=39, 100% the eligible pts) neointimal regrowth. There was one subacute stent thrombosis with subsequent acute myocardial infarction and death in the uncoated group.

CONCLUSION

The implantation of heparin-coated stents in nonselected population is well tolerated and associated with no clinical or angioscopic evidence of new thrombus formation, resulting in favorable long-term clinical and angiographic outcome.

Stenting in small coronary arteries (SISCA) trial. A randomized comparison between balloon angioplasty and the heparin-coated beStent

OBJECTIVES

The purpose of this study was to assess the clinical and angiographic benefits of elective stenting in coronary arteries with a reference diameter of 2.1 to 3.0 mm, as compared with traditional percutaneous transluminal coronary angioplasty (PTCA).

BACKGROUND

The problems related to small-vessel stenting might be overcome using modern stents designed for small vessels, combined with effective antiplatelet therapy.

METHODS

In five centers, 145 patients with stable or unstable angina were randomly assigned to elective stenting treatment with the heparin (Hepamed)-coated beStent or PTCA. Control angiography was performed after six months. The primary end point was the minimal lumen diameter (MLD) at follow-up. Secondary end points were the restenosis rate, event-free survival and angina status.

RESULTS

At follow-up, there was a trend toward a larger MLD in the stent group (1.69 +/- 0.52 mm vs. 1.57 +/- 0.44 mm, p = 0.096). Event-free survival at follow-up was significantly higher in the stent group: 90.5% vs. 76.1% (p = 0.016). The restenosis rate was low in both groups (9.7% and 18.8% in the stent and PTCA groups, respectively; p = 0.15). Analyzed as treated, both the MLD and restenosis rate were significantly improved in patients who had stents as compared with PTCA.

CONCLUSIONS

In small coronary arteries, both PTCA and elective stenting are associated with good clinical and angiographic outcomes after six months. Compared with PTCA, elective treatment with the heparin-coated beStent improves the clinical outcome; however, there was only a nonsignificant trend toward angiographic improvement.