Long-term clinical outcomes and thrombosis rates of sirolimus-eluting versus paclitaxel-eluting stents in an unselected population with coronary artery disease (REWARDS registry)

Preclinical evaluation of a novel abluminal surface coated sirolimus eluting stent with biodegradable polymer matrix

BACKGROUND

Second generation of drug eluting stents (DES) has attempted to improve safety using abluminal sirolimus drug delivery with biodegradable polymers matrix. The present preclinical study was designed to investigate the safety and efficacy profile of Abluminus™ stents (SES). This is a new coronary stent with sirolimus and biodegradable polymer matrix coated on abluminal stent and balloon surface.

METHODS

SES were compared with two controls: bare metal stent (BMS) and BMS + polymer coated stents (PC). All devices (40 stents) were implanted in porcine coronary arteries with primary endpoint of endothelialization at 7 days and subsequent histological and morphometric evaluations at 7, 30 and 90 days.

RESULTS

Early endothelialization at seven days was complete in all stents. Histology at 30 days revealed minimum inflammation in all groups and increased at 90 days in PC group while it was absent at 180 days. Thirty day morphometry showed significantly reduction of neointimal area in Abluminus™ (SES 0.96±0.48 mm(2); BMS 1.83±0.34 mm(2); PC 1.76±0.55 mm(2); P<0.05); after 90 days neointimal area was 1.10±0.54 mm(2) for SES; 1.92±0.36 mm(2) for BMS; and 1.94±0.48 mm(2) for PC; P<0.05). Neointimal thickness at 30 and 90 days respectively was 0.15±0.07 and 0.18±0.10 mm for SES, 0.57±0.08 and 0.61±0.09 mm for BMS and 0.52±0.09 and 0.59±0.08 mm, P<0.001 for PC group.

CONCLUSIONS

The most significant experimental evidence appears to be earlier endothelialization at 7 days for SES which led to safety of the device. Efficacy of the device was also observed by a reduced neointimal thickness and minimized inflammatory score at all follow-ups. Termination of antiplatelet at 30 days has not shown any further complications. Polymer thickness was almost in negligible amount at 180 days with no inflammation.

Risk of long-term dual antiplatelet therapy following drug-eluting stent implantation in octogenarians

OBJECTIVES

To evaluate the risk of long-term dual antiplatelet therapy (DAT) following drug-eluting stent (DES) implantation in octogenarians.

BACKGROUND

DES implantation requires DAT; however, DAT-associated risk in octogenarians remains unclear.

METHODS

Two-hundred and six consecutive octogenarians (130 men, 83.3 ± 3.4 years) underwent stent implantation (104 bare metal stents [BMSs] and 102 DESs) and 38.0 ± 13.2 months of follow-up.

RESULTS

Significantly more DES patients received DAT. The incidence of bleeding events was similar in the DES and BMS groups for 1 year (total: 10.8% vs 5.8%, P = 0.19; major: 4.9% vs 2.9%, P = 0.70). However, after 2 years, significantly more bleeding events occurred in the DES group than the BMS group (total: 2 years, 21.6% vs 9.6%, P = 0.02; 3 years, 29.4% vs 11.5%, P = 0.001; 4 years, 31.4% vs 15.4%, P = 0.007; major: 2 years, 12.7% vs 3.8%, P = 0.04; 3 years, 18.6% vs 5.8%, P = 0.005; 4 years, 19.6% vs 6.7%, P = 0.006). Overall, significantly more total bleeding events (31.4% vs 15.4%, P = 0.007) and major bleeding events (19.2% vs 6.7%, P = 0.006) were observed in the DES group than in the BMS group. The adjusted hazard ratios and 95% confidence intervals (CI) were as follows: total bleeding events, 2.203 (95% CI: 1.065-4.556; P = 0.033); major bleeding events, 4.324 (1.506-12.414; P = 0.007).

CONCLUSIONS

DAT was associated with an increased risk of bleeding events in octogenarians after 2 years. DAT discontinuation should be considered for octogenarians 1-year post-DES implantation.

Twelve-month outcomes in patients with diabetes implanted with a zotarolimus-eluting stent: results from the E-Five Registry

Objective

To retrospectively evaluate the 12-month effectiveness of the Endeavor zotarolimus-eluting stent (ZES) in diabetic versus non-diabetic patients enrolled in the E-Five Registry.

Design and Setting

The E-Five Registry is a prospective, multicentre registry of 8314 patients presenting with symptomatic coronary artery disease treated with the Endeavor (ZES). Patients were treated at 188 centres located in 37 countries across Europe, Latin America and Asia Pacific.

Patients

There were 2721 (32.7%) patients with diabetes (DM) and among these patients 682 were insulin-treated (ITDM) and 2039 were non-insulin-treated diabetic patients (NITDM).

Interventions

All enrolled patients received an Endeavor ZES and were followed for 12 months.

Main outcome measurements

The primary outcome measure was major adverse cardiac event (MACE) at 12 months. Secondary endpoints included target lesion revascularisation (TLR), target vessel revascularisation (TVR), target vessel failure (TVF) and stent thrombosis.

Results

Compared with non-DM patients, DM patients had higher rates of MACE (9.7% vs 6.4%, p<0.001), TLR (5.3% vs 4.0%, p=0.028) and Academic Research Consortium (ARC) definite and probable stent thrombosis (1.5% vs 0.9%, p=0.041). Compared with non-DM patients, ITDM patients had higher rates of MACE (12.6% vs 6.4%, p<0.001). ITDM patients had higher rates of death (6.7% vs 1.7%, p<0.001), cardiac death (4.5% vs 1.2%, p<0.001) and TLR (6.5% vs 4.0%, p=0.011) than non-DM patients.

Conclusions

The Endeavor ZES performed well in DM patients; however, DM patients experienced higher rates of adverse clinical events compared with non-DM patients.

Trial Reg No

Clinical trial registration information: http://www.clinicaltrials.gov; Unique identifier: NTC00623441

Vertebral Artery Origin Stents Revisited

BACKGROUND

Vertebral origin angioplasty and stenting (VOAS) with bare metal stents is associated with a high rate of in-stent restenosis (ISR).

OBJECTIVE

We evaluated the rate of ISR after VOAS with drug-eluting stents.

METHODS

Twenty patients (15 men, 5 women; age range, 36–88 years; mean, 63.7 years) were treated for VOAS with a paclitaxel-eluting stent (Taxus Express2, Boston Scientific, Natick, Massachusetts). Stenosis at follow-up was quantified as insignificant (0%–24%), mild (25%–49%), moderate (50%–74%), and severe (75%–100%). ISR was defined using a binary criteria of &gt; 50% stenosis at follow-up angiography.

RESULTS

All procedures were technically successful with no periprocedural complications. Follow-up angiography (range, 4–48 months; mean, 14.7 months) showed insignificant stenosis in 9 patients, mild in 6, moderate in 4, and severe in 1. In 1 patient with “moderate” stenosis, the stent migrated distally; therefore, the lesion restenosis was not within the stent. Thus, 4 of 19 patients (21%) exhibited binary moderate or severe ISR, and 5 of 20 showed restenosis at the lesion (25%). The patient with severe stenosis developed stent thrombosis &gt; 3 years after VOAS.

CONCLUSION

VOAS with drug-eluting stents was associated with a low incidence of periprocedural complications. Although the rate of restenosis was half that seen with the use of bare metallic stents, 21% of patients still developed moderate or severe ISR. These patients may require ≥ 1 revascularization procedures. The risk of delayed stent thrombosis may necessitate lifelong dual antiplatelet medications.

Development of a novel prohealing stent designed to deliver sirolimus from a biodegradable abluminal matrix

BACKGROUND

We aimed to demonstrate that, by separating endothelial progenitor cell capture from sirolimus delivery through the application of drug to the abluminal surface of the stent, the degree of endothelialization can be enhanced.

METHODS AND RESULTS

Stainless steel R Stents, with biodegradable SynBiosys polymer coating with sirolimus abluminally applied and surface modified with anti-CD34 antibody were prepared at 2 dosages (low-dose sirolimus [LD-Combo, 2.5 microg sirolimus/mm] and full-dose sirolimus [Combo, 5 microg sirolimus/mm). These Combo stents and the Cypher stent (10 microg sirolimus/mm) were deployed in 98 normal porcine arteries and harvested for pharmacokinetic analysis at 0.25, 1, 3, 7, 14, 28, and 35 days. The LD-Combo stents showed faster early release (50%total dose in 72 hours) than the Combo and Cypher. At 30 days, drug release was near complete with both Combo stents, whereas 20% of drug remained on the Cypher stents. To assess efficacy, a total of 50 stents (Xience V=8, Cypher=8, Genous bioengineered R stent=6, LD-Combo=14, and Combo=14) were implanted in 18 pigs for 14 and 28 days. Optical coherence tomography was performed, and stents were harvested for histology. At 28 days, there was less neointimal thickness with Combo (0.173+/-0.088 mm) compared with Cypher (0.358+/-0.225 mm), LD-Combo (0.316+/-0.228 mm), and Xience V (0.305+/-0.252 mm; P<0.00001). Immunohistochemical analysis of endothelialization showed that Genous bioengineered R stent had the highest degree of platelet endothelial cell adhesion molecule expression (87%) followed by the Combo (75%), LD-Combo (65%), and Cypher (58%).

CONCLUSIONS

Both optical coherence tomography and histology demonstrate that anti-CD34 sirolimus-eluting stents promote endothelialization while reducing neointimal formation and inflammation.

In-hospital complications and long-term outcomes of the paclitaxel drug-eluting stent in acute ST-elevation myocardial infarction: a real-world experience from a high-volume medical center

BACKGROUND

The paclitaxel drug-eluting stent (Taxus, Boston Scientific) is FDA approved for treatment of coronary artery disease in simple, noncomplex coronary lesions. In this registry, we sought to investigate the procedural success and long-term outcomes of patients receiving the Taxus stent in the setting of acute ST-elevation myocardial infarction (STEMI) in a busy single-center interventional program.

METHODS

This is a single-center retrospective analysis of prospectively collected in-hospital data with postdischarge follow-up achieved by phone calls and review of medical records. Data were audited by an independent monitor, and outcomes were adjudicated by an experienced interventional cardiologist. All patients with STEMI over the period of 2 years (2005 and 2006) with native de novo lesions who received the Taxus stent were included. Patients receiving bare metal stents were excluded. The primary outcome was the combined end point of cardiac death, recurrent nonfatal MI, and target lesion revascularization (TLR) on follow-up.

RESULTS

Of 198 patients included in this study, follow-up data were obtained in 172 (86.9%) patients. The mean age was 63+/-14.9 years. There were 59.1% males. Patients had the following cardiac risk factors: diabetes 20.7%, hypertension 60.6%, hyperlipidemia 87.8%, and current smoking 48%. In-hospital complications included death 5.1%, acute closure with stent thrombosis 1%, vascular complications 2.9%, and cardiogenic shock 6.6%. The mean follow-up period (days) was 317.3+/-239.3. The primary end point of cardiac death, nonfatal MI, and TLR was met in 12.4%. Individual end points on follow-up were cardiac death 2.5%, total death 4.9%, TLR 8.1%, target vessel revascularization 19.9%, stroke 1.2%, nonfatal MI 5%, and acute stent thrombosis 5.5% (definite 4.3%, probable 0.6%, possible 0.6%; Academic Research Consortium definition).

CONCLUSION

The use of the Taxus stent in acute STEMI is associated with a low postdischarge combined end point of cardiac death, nonfatal MI, and TLR and a definite/probable 4.9% in-stent thrombosis rate, which is within the reported range of data published in "real-world" registry.

A clinical risk score for prediction of stent thrombosis

The aim was to develop a clinically useful patient risk score predictive for stent thrombosis (ST). Using readily available baseline clinical and angiographic characteristics, a Cox proportional hazards multivariate model was used to identify significant (p <0.10) predictors of ST through 1 year in 2,487 patients receiving a TAXUS Express (Boston Scientific Corp., Natick, Massachusetts) drug-eluting stent (DES) in the ARRIVE 1 registry. Hazard ratios of significant predictors were rounded to an integer value ranging from 2 to 5. These values were summed for a maximum possible score of 24. The model was validated using 1-year data from a similar DES data set (ARRIVE 2, n = 4,820 patients). The 8 significant predictors found were thienopyridine therapy discontinuation before 6 months, insulin-requiring diabetes, smoker at baseline, left main stent placement, multiple stent placement, lesion length >28 mm, moderate to severe lesion calcification, and reference vessel diameter <3 mm. Model discrimination was high, indicated by an area under the receiver-operator characteristic curve of 0.819. Stratification of patients into low-, medium-, and high-risk groups showed that ST developed in 0.8% of patients with a score <6, 3.6% of patients with a score of 7 to 13, and 12.6% of patients with a score >or=14. In conclusion, using 8 readily available clinical and angiographic characteristics, we defined an ST risk score for patients receiving a DES during the first year. Analysis of patients from ARRIVE 1 and 2 showed that most (73%) were in the lowest risk category, with 25% in the moderate risk category. Less than 2% were at highest risk of developing ST.

Drug-eluting compared with bare-metal coronary stents among elderly patients

OBJECTIVES

We sought to determine whether drug-eluting stents (DES) were associated with improved clinical outcomes compared with bare-metal stents (BMS) among a nationally representative, nonexperimental elderly patient cohort.

BACKGROUND

Randomized controlled clinical trials comparing DES and BMS for treatment of coronary artery disease indicate that although the use of DES reduces rates of coronary restenosis after percutaneous coronary intervention, it does not reduce the rates of mortality or acute myocardial infarction (AMI). Nevertheless, clinical outcomes of DES in nonexperimental, routine clinical practice are uncertain.

METHODS

We assembled a retrospective cohort of elderly Medicare beneficiaries (n = 76,525) who received DES within 9 months after Food and Drug Administration approval of the sirolimus-eluting stent (April 2003 to December 2003). Using propensity score methods, we assembled 2 matched control cohorts who received BMS from July 2002 to March 2003 (historical controls) or from April 2003 to December 2003 (contemporary controls). Patient enrollment and claims records were obtained through December 2005 to ascertain mortality, hospitalization for AMI, and subsequent coronary revascularization.

RESULTS

Receipt of a DES was associated with a significant survival benefit, with an adjusted mortality hazard ratio of 0.83 (95% confidence interval 0.81 to 0.86) compared with contemporary controls, and a hazard ratio of 0.79 (95% confidence interval 0.77 to 0.81) compared with historical controls (control group heterogeneity: p < 0.001). Patients with DES had significantly lower adjusted rates of revascularization procedures within the first 2 years after PCI and lower hospitalization rates for subsequent AMI.

CONCLUSIONS

In contrast to clinical trial results, DES receipt was associated with fewer subsequent revascularization procedures, lower rates of hospitalization for AMI, and improved survival among elderly Medicare beneficiaries.

Impact of in-stent restenosis on death and myocardial infarction

Although drug-eluting stents reduce restenosis and target lesion revascularization compared with bare metal stents (BMSs), the specter of late stent thrombosis has curbed enthusiasm for the widespread use of drug-eluting stents. Alternatively, increasing BMS use would increase restenosis and potentially increase adverse events. The presentation and outcomes of BMS restenosis are controversial. We evaluated 2,539 patients with BMS restenosis referred for repeat revascularization. Major adverse cardiac events, including mortality and myocardial infarction (MI), were assessed at clinical presentation, 30 days, and 6 months. Patients with acute presentation (i.e., unstable angina requiring hospitalization or MI) were compared with patients with stable presentation. At presentation, 19.2% of patients were asymptomatic, 27.5% had exertional angina, 46.6% had unstable angina, and 6.7% had MI. Mortality and MI rates were 1.1% and 1.4%, respectively, at 30 days and 3.3% and 4.5%, respectively, at 6 months. Patients with acute coronary syndrome (ACS) and those without ACS had similarly low mortality rates at 30 days (1.2% ACS vs 1.0% non-ACS, p = 0.65) and 6 months (3.4% ACS vs 3.3% non-ACS, p = 0.93) and MI rates at 30 days (1.3% ACS vs 1.4% non-ACS, p = 0.87) and 6 months (4.7% ACS vs 4.3% non-ACS, p = 0.65). Combined major adverse cardiac events were similar at 30 days (2.5% vs 2.1%, p = 0.53) and 6 months (7.4% ACS vs 6.9%, non-ACS, p = 0.65). In conclusion, although BMS restenosis often manifests as an ACS, it is associated with a low incidence of 6-month major adverse cardiac events and does not predict a negative outcome.