Incidence, predictors, and outcomes of coronary dissections left untreated after drug-eluting stent implantation†

Stent thrombosis in Sweden: a report from the Swedish Coronary Angiography and Angioplasty Registry

BACKGROUND

The objective was to evaluate the role of risk factors and stent type for stent thrombosis (ST) using a large real world registry.

METHODS AND RESULTS

We evaluated all consecutive coronary stent implantations in Sweden from May 1, 2005, to June 30, 2007. All cases of ST, documented in the Swedish coronary angiography and angioplasty registry until September 21, 2008, were analyzed. ST was registered in 882 of 73 798 stents. Acute coronary syndromes, insulin-treated diabetes mellitus, smoking, previous coronary intervention, warfarin treatment, small stent diameter, and stenting in restenotic, complex, or bypass graft lesions had the strongest association with ST in the multivariable statistical model. There were considerable differences in the frequency of ST between different stent brands. The overall risk of ST was lower in drug-eluting stents compared with bare metal stents (adjusted risk ratio, 0.79; 99% CI, 0.63 to 0.99). However, from 6 months after stent implantation and onward, the risk for ST was higher in drug-eluting stents compared with bare metal stents (adjusted risk ratio, 2.02; 99% CI, 1.30 to 3.14).

CONCLUSIONS

ST is a multifactor disease, and the incidence varies considerably between patients based on clinical, vessel, and stent characteristics. For drug-eluting stents compared with bare metal stents, the risk pattern was biphasic; initially, bare metal stents demonstrated a higher risk of ST; whereas after the first months, ST risk was higher with drug-eluting stents. Our findings highlight the need for prospective randomized studies with head-to-head comparisons between different stents.

Very long-term results comparing a simple versus a complex stenting strategy in the treatment of coronary bifurcation lesions

BACKGROUND

The optimal stenting strategy for coronary bifurcation lesions has not yet been defined, especially given the lack of very long-term data (>24 months). We compared our long-term results of a simple vs complex stenting strategy in patients with bifurcation lesions.

METHODS

We retrospectively selected subjects undergoing percutaneous coronary intervention (PCI) with stenting in a bifurcation lesion between June 2002 and December 2005, comparing those treated with a simple technique vs those treated with a complex one. The primary end-point was the rate of major adverse cardiac events (MACE) at >24 months of follow-up.

RESULTS

A total of 326 patients were included, 64.7% treated with a simple technique (Group A) and 35.3% with a complex strategy (Group B). Drug-eluting stents were used in 82.0% and 73.0%, respectively (P = 0.059), final kissing balloon in 47.9% and 53.0% (P = 0.37), and procedural success obtained in 99.5% and 99.1% (P = 0.66). After a median of 34 months, MACE occurred in 52 (26.5%) in Group A and in 32 (31.4%) in Group B (P = 0.37), cardiac death in six (3.1%) vs four (3.9%, P = 0.70), myocardial infarction in 13 (6.6%) vs 6 (5.9%, P = 0.80), target vessel revascularization in 36 (18.4%) vs 29 (28.4%, P = 0.04), and bypass in five (2.6%) vs two (2%, P = 0.74). Definite stent thrombosis was adjudicated in two (1%) vs one (0.9%, P = 0.98).

CONCLUSIONS

This study, comparing simple and complex stenting strategies for the treatment of coronary bifurcation lesions, shows that both techniques are associated with favorable clinical results and low adverse events rates at long-term follow-up.

Percutaneous coronary implantation of sirolimus-eluting stents in unselected patients and lesions: clinical results and multiple outcome predictors

BACKGROUND

Sirolimus-eluting stents (SES) prevent restenosis and repeat percutaneous coronary intervention (PCI), but safety data in unselected patients are limited, especially for intermediate-term follow-up.

METHODS

All patients undergoing SES implantation at 4 Italian centers were enrolled into a dedicated database. Baseline, procedural, and outcome data at discharge and at follow-up were abstracted. Outcomes of interest were the occurrence of major adverse cerebrocardiovascular events (MACCE) at 6 months, as well as long-term event-free survival and multivariable event predictors.

RESULTS

One thousand four hundred twenty-four patients were enrolled (2,915 lesions, treated with 3,305 stents). Specifically, 1,074 (75.4%) subjects had multivessel disease, 399 (28.1%) had diabetes, 89 (6.3%) had ST-elevation myocardial infarction, and 44 (3.1%) underwent unprotected left main intervention. At 6 months, MACCE had occurred in 121 (9.0%) patients. After a median of 48.7 months (first-third quartile 41.8-55.3), MACCE-free survival was 69.2%+/-2.6%, with definite stent thrombosis occurring acutely in 6 (0.4%), subacutely in 11 (0.8%), after 30 days in 12 (0.8%), and cumulatively in 28 (2.0%). Major multivariable outcome predictors were diabetes (target lesion revascularization [TLR], MACCE), ejection fraction (TLR, MACCE), and maximal balloon length (TLR).

CONCLUSIONS

This large cohort of unselected patients supports the overall safety of unrestricted percutaneous SES implantation, as shown by the low rates of stent thrombosis. Event attrition remains, however, high at long-term follow-up, driven mainly by target vessel revascularization, with diabetes and ejection fraction as the most important prognostic factors.

Next-generation drug-eluting stents in coronary artery disease: focus on everolimus-eluting stent (Xience V)

Percutaneous coronary revascularization has been a mainstay in the management of coronary artery disease since its introduction in the late 1970s. Bare-metal stents and, more recently, first-generation drug-eluting stents (DES), such as sirolimus-eluting (Cypher^®) and paclitaxel-eluting stents (Taxus^®), have further improved results of percutaneous coronary intervention (PCI) by improving early results and reducing the risk of restenosis. There is currently debate on the safety of these first-generation DES, given the potential for late stent thrombosis, especially after discontinuation of dual antiplatelet therapy. There are well known caveats on the performance of their respective metallic stent platforms, delivery, and dilation systems, and polymer coatings. Second-generation DES, such as zotarolimus-eluting (Endeavor^®) and everolimus-eluting stents (Xience V^®), have recently become available in the USA and/or Europe. The Xience V stent holds the promise of superior anti-restenotic efficacy as well as long-term safety. In addition, this stent is based on the Multi-link platform and delivery system. Recently available data already suggest the superiority of the Xience V stent in comparison to the Taxus stent in terms of prevention of restenosis, without significant untoward events. Nonetheless, the number of patients studied and the follow-up duration are still too limited to enable definitive conclusions. Only indirect meta-analyses can be used to date to compare the Xience V with the Cypher. This systematic review tries to provide a concise and critical appraisal of the data in support of the Xience V everolimus-eluting stent.

Clinical outcomes after heterogeneous overlap stenting with drug-eluting stents and bare-metal stents for de novo coronary artery narrowings

When it is difficult to deliver multiple drug-eluting stents (DES) or when size constraints limit DES implantation, bare-metal stents (BMS) may be implanted contiguous to DES. However, the clinical outcomes after overlapping DES and BMS implantation are not known. From September 2004 to June 2006, 4,872 consecutive patients who underwent percutaneous coronary intervention consented to be enrolled in a prospective registry. Of these patients, 44 (0.9%) with de novo lesions were treated with DES and BMS overlap stenting. All patients were followed to 12 months for the assessment of clinical outcomes. The average implanted stent diameter was 2.68 +/- 0.30 mm for DES and 2.35 +/- 0.38 mm for BMS. Overlapping BMS were implanted distal to DES in all but 1 case. One patient (2.3%) experienced acute stent thrombosis and died 2 days after the procedure. No other patient died or had a myocardial infarction during 12 months. The target vessel revascularization rate at 12 months, however, was 31.8%, mainly driven by diffuse in-stent restenosis in the BMS segments. In conclusion, the incidence of DES and BMS overlap stenting is rare in daily practice, but this procedure is associated with a high rate of target vessel revascularization.

Long-term clinical and angiographic outcomes of treatment of unprotected left main coronary artery stenosis with sirolimus-eluting stents

Favorable early results of percutaneous drug-eluting stents in unprotected left main (LM) disease are available, but outcome data beyond 6 to 10 months are lacking. We evaluated the long-term results of sirolimus-eluting stents (SESs) in patients with LM disease. From November 2002 to December 2004, consecutive patients with LM disease, without contraindications to double antiplatelet therapy and undergoing SES implantation, were enrolled prospectively. The primary end point of the study was occurrence of major adverse cardiovascular events. In total 85 patients were treated with 118 SES and followed for 595 +/- 230 days. Event-free survival rates at 1 year and 2 years were 85.5% and 78.6%, respectively. Only 2 deaths occurred overall (2.4%), the first in-hospital in a very high-risk patient according to the European System for Cardiac Operative Risk Evaluation and the second in a patient with severe systolic dysfunction already at the index procedure). Myocardial infarction was adjudicated in 3 patients (3.6%), 2 occurring periprocedurally and 1 during follow-up for a de novo nontarget lesion. There were 7 (10.8%) target lesion revascularizations at 24 months, with all but 1 percutaneous and in a subject with bifurcation LM disease at baseline. At 9-month angiography, late loss was 0.15 +/- 0.81 mm and restenosis rate was 8.2%. An increased incidence of adverse events was noted in patients undergoing SES after dilation with extremely oversized balloons. No case of stent thrombosis was reported. In conclusion, this single-center experience suggests that percutaneous use of SESs to treat LM disease in unselected high-risk patients is safe and effective even 1 year after implantation.

Late and very late thrombosis of drug-eluting stents: evolving concepts and perspectives

Coronary stents are the mainstay of percutaneous coronary revascularization procedures and have significantly decreased the rates of acute vessel closure and restenosis. Stent thrombosis (ST) after percutaneous coronary intervention is an uncommon and potentially catastrophic event that might manifest as myocardial infarction and sudden death. Optimization of stent implantation and dual antiplatelet therapy have markedly reduced the occurrence of this complication. Bare-metal stent (BMS) thrombosis occurs in <1% of the cases, usually within the first month after implantation. The advent of drug-eluting stents (DES) has raised concerns regarding later occurrence of ST, beyond the traditional 1-month timeframe, especially in complex lesion subsets that were excluded from randomized trials that compared BMS to DES. There is widespread controversy regarding the actual incremental risk associated with DES. Recent studies suggest a 0.5% increased long-term thrombosis risk with DES; however, the clinical significance of these events remains under debate. The degree of protection achieved by dual antiplatelet therapy and optimal duration of treatment are under investigation. Novel stent designs might potentially decrease the incidence of this event. In this review, we will describe the current knowledge of the pathophysiology of late DES thrombosis, although many aspects remain incompletely understood.

Testing prospectively the effectiveness and safety of paclitaxel-eluting stents in over 1000 very high-risk patients

BACKGROUND

Paclitaxel-eluting stents (PES) have been proved effective in randomized trials enrolling highly selected patients. Yet, given the uncertainty concerning results of PES implantation in very high-risk patients and lesions, we designed a prospective multicenter registry, the Taxus in Real-life Usage Evaluation (TRUE) Study. STUDY DESIGN, PATIENT CHARACTERISTICS AND IN-HOSPITAL OUTCOMES: Consecutive patients undergoing PES implantation were enrolled provided that the target lesion treated with PES was an unprotected left main (ULM), a true bifurcation, a chronic total occlusion (CTO), a long lesion (>28 mm), located in a small vessel (<2.75 mm), or the patient had diabetes mellitus. Clinical events will be adjudicated at 1, 7 and 12 months, with 4- to 8-month angiographic follow-up. The primary end-point will be the 7-month occurrence of major adverse cardiovascular events (MACE, i.e. the composite of cardiac death, non-fatal myocardial infarction [MI], coronary artery bypass grafting [CABG] and percutaneous target vessel revascularization [TVR]). To date, patient enrollment has been completed reaching the target of 1065 subjects. These included 322 (30.2%) diabetics, 115 (10.8%) subjects undergoing PES implantation for ULM, 229 (21.5%) in a bifurcation, 191 (17.9%) in a CTO, 430 (40.4%) in a small vessel, and 289 (27.1%) in a long lesion. An average of 1.5+/-0.6 vessels and 2.0+/-1.0 lesions were treated per patient, with 2.0+/-1.2 PES implanted per patient, and a 46+/-30 mm total PES length per patient. In-hospital MACE occurred in 39 (3.7%) patients, with 2 (0.2%) cardiac deaths, 32 (3.0%) MI, 5 (0.5%) TVR, no CABG, and 4 (0.4%) acute stent thromboses.

IMPLICATIONS

Despite the availability of randomized trials, only carefully designed and prospective registries can provide timely and accurate assessment of the risk-benefit profile of PES in very high-risk patients. Indeed, the TRUE Study, including as much as 115 ULM and 229 bifurcation interventions, should give important insights into the outcome of PES in such an unprecedented and challenging context.