Outcomes of stent thrombosis and restenosis during extended follow-up of patients treated with bare-metal coronary stents

Very late stent thrombosis occurring simultaneously in sirolimus-eluting stents and bare-metal stent in three different coronary vessels

A 36-year-old male was diagnosed with acute inferior myocardial infarction (MI). Emergent coronary angiography (CAG) revealed an occlusive lesion in the distal segment of the right coronary artery (RCA). The proximal and distal sites of the lesion were treated with a bare-metal stent (BMS) and a sirolimus-eluting stent (SES), respectively. Nine days later, he underwent elective percutaneous coronary intervention (PCI). Two SESs were implanted for the stenotic lesion in the left anterior descending artery (LAD), in addition to one SES for the mid-stenotic lesion in the left circumflex artery (LCX). Nine months after PCI, follow-up CAG revealed no restenosis at any stent-implanted site. Two years and 4 months after PCI, he was admitted to our hospital because of acute anterior MI. Emergent CAG revealed total thrombotic occlusion in the in-stent proximal site of LAD. Moreover, thrombotic lesions were also observed in in-stent sites: in both BMS of RCA and SES of LCX. He underwent intracoronary aspiration thrombectomy and plain old balloon angioplasty for LAD using intra-aortic balloon pumping. PCI for the thrombotic lesions in RCA and LCX was not performed. Seventeen days after the stent thrombosis, CAG revealed the complete disappearance of thrombi in LAD, LCX, and RCA.

Clinical outcomes of drug-eluting versus bare-metal in-stent restenosis

In-stent restenosis (ISR) is a challenging syndrome that affects drug-eluting stents and bare-metal stents. However, data comparing the outcomes of drug-eluting versus bare-metal ISR are limited. Our objective was to evaluate the long-term clinical outcomes of drug-eluting versus bare-metal ISR. Patients who underwent percutaneous coronary intervention at Cleveland Clinic for ISR from 05/1999 to 06/2007 were included. Unadjusted outcomes were tested using Kaplan-Meier curves followed by multivariable adjusted Cox proportional hazards analyses. Twenty seven variables, including type of stent used to treat ISR and procedural date, were included. The primary end point was a composite of death, myocardial infarction (MI), or target lesion revascularization (TLR). The secondary endpoints were components of the primary endpoint. Of 931 patients identified, 225 had drug-eluting ISR and 706 had bare-metal ISR. There were 279 cumulative events for a median follow-up of 3.2 years. The primary endpoint was not different between drug eluting and bare-metal ISR (22% versus 33%, adjusted hazard ratio [HR] 1.14; 95% confidence interval [CI], 0.79-1.66; P = 0.49). The secondary endpoints of death (8% versus 16%, adjusted HR 1.05; 95% CI, 0.56-1.98; P = 0.88), MI (4% versus 5%, adjusted HR 1.48; 95% CI, 0.54-4.04; P = 0.45), and TLR (15% versus 16%, adjusted HR 1.30; 95% CI, 0.81-2.11; P = 0.28) were also not different. This study represents the largest analysis comparing drug-eluting to bare-metal ISR. On multivariable Cox proportional hazard analyses, drug-eluting and bare-metal ISR have similar long term outcomes.

Intravascular ultrasound findings in patients with very late stent thrombosis after either drug-eluting or bare-metal stent implantation

OBJECTIVES

This study compared intravascular ultrasound (IVUS) findings at drug-eluting stent (DES) and bare-metal stent (BMS) sites in patients with very late stent thrombosis (VLST).

BACKGROUND

VLST is being increasingly identified since the introduction of DES. VLST can also develop after BMS placement, but the underlying mechanisms remain unknown.

METHODS

A total of 30 consecutive VLST patients with acute myocardial infarction (DES, n = 23; BMS, n = 7) were enrolled. Patients underwent IVUS examination before coronary angioplasty.

RESULTS

The baseline characteristics were similar for the 2 groups, with the exception of reference vessel size, lesion length, stent length, minimal lumen diameter, and diameter stenosis after the procedure. Overall, VLST occurred at a mean 50.8 +/- 36.2 months after the index procedure, and occurred earlier after DES than BMS (33.2 +/- 12.5 months vs. 108.4 +/- 26.5 months, p < 0.001). IVUS variables were generally similar for the 2 groups. However, plaque burden at the distal reference segment, stent, and neointimal area of the in-stent segment were smaller in the DES group. Stent malapposition was observed in 73.9% of DES patients, but in no BMS patients (p = 0.001). Disease progression with neointimal rupture within the stent was observed in 10 DES patients (43.5%) and 7 BMS patients (100%; p = 0.010).

CONCLUSIONS

Stent malapposition was unique to DES-related VLST, whereas disease progression with neointimal rupture was more common in BMS patients. These findings suggest that different biological mechanisms underlie VLST development depending upon the stent type.

The outcome of primary percutaneous coronary intervention for stent thrombosis causing ST-elevation myocardial infarction

BACKGROUND

There are very few scientific data about the effectiveness of primary percutaneous coronary intervention (PCI) in patients with ST-elevation myocardial infarction (STEMI) due to stent thrombosis (ST). The purpose of the present study is to investigate the efficacy and outcome of primary PCI for STEMI due to ST in the largest consecutive patient population with ST reported to date.

METHODS

A total of 2,644 consecutive STEMI patients undergoing primary PCI were retrospectively enrolled into the present study. The primary end point of this study was successful angiographic reperfusion defined as postprocedural Thrombolysis In Myocardial Infarction grade III flow. The secondary end points were cardiovascular death and reinfarction.

RESULTS

Stent thrombosis was the cause of STEMI in 118 patients (4.4%). In patients with ST, angiographic success (postprocedural Thrombolysis In Myocardial Infarction grade III flow) was worse than in patients with de novo STEMI (76.3% vs 84.8%, P = .01). Patients with ST had significantly higher incidence of in-hospital cardiovascular mortality than patients with de novo STEMI (10.2% vs 5.3%, P = .02). In-hospital reinfarction rate was similar in both groups. In addition, long-term (mean 22 months) cardiovascular mortality and reinfarction rates were significantly higher in patients with ST compared with those without (17.4% vs 10.5%, P = .02 and 15.6% vs 9.5%, P = .03, respectively).

CONCLUSIONS

Primary PCI for treatment of ST is less effective, and these patients are at increased risk for in-hospital and long-term mortality compared with patients undergoing primary PCI due to de novo STEMI.

Mechanisms of nonfatal acute myocardial infarction late after stent implantation: the relative impact of disease progression, stent restenosis, and stent thrombosis

BACKGROUND

The impact of stent restenosis, stent thrombosis, or progression of disease at another site as responsible mechanisms of acute myocardial infarction (AMI) after stent implantation is not clear.

METHODS

By searching our catheterization laboratory database for a 4-year period, 91 cases of nonfatal AMI at least 1 month after stent implantation (32.6% drug-eluting stents) were identified. By detailed comparison of post-AMI with the initial percutaneous coronary intervention angiogram, the mechanism of AMI was analyzed.

RESULTS

Acute myocardial infarction was attributed to disease progression at another site in 42 (46.2%), stent restenosis in 35 (38.4%), and stent thrombosis in 10 (11%) cases. The AMI mechanism could be either stent related or disease progression (nonidentifiable culprit lesion) in 4 cases (4.4%). The median time from percutaneous coronary intervention to AMI was 27, 19, and 9 months for disease progression at another site, restenosis, and stent thrombosis group, respectively (P = .03). ST-elevation myocardial infarction occurred in 38.1% of the disease progression, in 20% of the restenosis, and in 60% of the stent thrombosis cases (P = .046).

CONCLUSIONS

In a "real world" population, late after stent implantation, a patient has an almost equal probability to have suffered a nonfatal AMI from either stent restenosis/thrombosis or disease progression at another site. Continuous research efforts are necessary to equally address both stent therapy and disease progression.

Emerging drugs for coronary restenosis: the role of systemic oral agents the in stent era

Introduction of drug eluting stents (DES) during percutaneous coronary interventions significantly reduces the rate of angiographic restenosis, target lesion and vessel revascularization. In spite of these benefits, other clinical hard end points such as death or myocardial infarction were not reduced and, furthermore, new concerns associated with the presence of late and very late stent thrombosis have been raised. The requirement of long-term dual antiplatelet therapy is another limitation associated with DES. Conversely, in this decade, other options to DES have been simultaneously discussed in observational and randomized studies. Several registries and randomized trials using the systemic approach with anti-inflammatory, immunosuppressive or antiplatelet therapies have been identified and discussed in this manuscript. In spite of all randomized studies with oral therapies in the bare metal stent (BMS) era demonstrating positive reductions in coronary restenosis, this practice has not been introduced clinically. Furthermore, a recent randomized trial comparing oral sirolimus plus BMS versus DES demonstrated that the first approach was cost saving and of comparable efficacy to DES. Conclusive evidence of high incidence of late and very late stent thrombosis with DES, together with clinical limitations for its widespread use, has opened up a large opportunity to search for alternative therapies in coronary restenosis prevention.

The effect of cilostazol on stent thrombosis after drug-eluting stent implantation

Background and Objectives

Placement of drug-eluting stents (DES) can be complicated by stent thrombosis; prophylactic antiplatelet therapy has been used to prevent such events. We evaluated the efficacy of cilostazol with regard to stent thrombosis as adjunctive antiplatelet therapy.

Subjects and Methods

A total of 1,315 patients (846 males, 469 females) were prospectively enrolled and analyzed for the frequency of stent thrombosis. Patients with known risk factors for stent thrombosis, except diabetes and acute coronary syndrome, were excluded from the study. All patients maintained antiplatelet therapy for at least six months. To evaluate the effects of cilostazol as another option for antiplatelet therapy, triple antiplatelet therapy (aspirin+clopidogrel+cilostazol, n=502) was compared to dual antiplatelet therapy (aspirin+clopidogrel, n=813). Six months after stent placement, all patients received only two antiplatelet drugs: treatment either with cilostazol+aspirin (cilostazol group) or clopidogrel+aspirin (clopidogrel group). There were 1,033 patients (396 in cilostazol group and 637 in clopidogrel group) that maintained antiplatelet therapy for at least 12 months and were included in this study. Stent thrombosis was defined and classified according to the definition reported by the Academic Research Consortium (ARC).

Results

defined and classified according to the definition reported by the Academic Research Consortium (ARC). Results: During follow-up (561.7±251.4 days), 15 patients (1.14%) developed stent thrombosis between day 1 to day 657. Stent thrombosis occurred in seven patients (1.39%) on triple antiplatelet therapy and four patients (0.49%) on dual antiplatelet therapy (p=NS) within the first six months after stenting. Six months and later, after stent implantation, one patient (0.25%) developed stent thrombosis in the cilostazol group, and three (0.47%) in the clopidogrel group (p=NS).

Conclusion

During the first six months after DES triple antiplatelet therapy may be more effective than dual antiplatelet therapy for the prevention of stent thrombosis. However, after the first six months, dual antiplatelet treatment, with aspirin and cilostazol, may have a better cost benefit ratio for the prevention of stent thrombosis.

Appearance of lipid-laden intima and neovascularization after implantation of bare-metal stents extended late-phase observation by intracoronary optical coherence tomography

OBJECTIVES

We examined the neointimal characteristics of bare-metal stents (BMS) in extended late phase by the use of optical coherence tomography (OCT).

BACKGROUND

The long-term neointimal features after BMS implantation have not yet been fully characterized.

METHODS

Intracoronary OCT observation of BMS segments was performed during the early phase (<6 months, n = 20) and late phase (>or=5 years, n = 21) after implantation. Internal tissue of the BMS was categorized into normal neointima, characterized by a signal-rich band without signal attenuation, or lipid-leaden intima, with marked signal attenuation and a diffuse border. In addition, the presence of disrupted intima and thrombus was evaluated. Neovascularization was defined as small vesicular or tubular structures, and the location of the microvessels was classified into peristent or intraintima.

RESULTS

Normal neointima proliferated homogeneously, and lipid-laden intima was not observed in the early phase. In the late phase, lipid-laden intima, intimal disruption, and thrombus frequently were found in comparison with the early phase (67% vs. 0%, 38% vs. 0%, and 52% vs. 5%, respectively; p < 0.05). Persistent neovascularization demonstrated a similar incidence between the 2 phases. The appearance of intraintima neovascularization was more prevalent in the late phase than the early phase (62% vs. 0%, respectively; p < 0.01) and in segments with lipid-laden intima than in nonlipidic segments (79% vs. 29%, respectively; p = 0.026).

CONCLUSIONS

This OCT study suggests that neointima within the BMS often transforms into lipid-laden tissue during an extended period of time and that expansion of neovascularization from peristent to intraintima contributes to atherosclerotic progression of neointima.

Effectiveness of two-year clopidogrel + aspirin in abolishing the risk of very late thrombosis after drug-eluting stent implantation (from the TYCOON [two-year ClOpidOgrel need] study)

It remains unclear whether dual antiplatelet therapy >12 months might carry a better prognosis after percutaneous coronary intervention (PCI) with drug-eluting stents (DESs). To address the hypothesis that in the real world the risk of very late thrombosis after PCI with DESs can be decreased by an extended use of clopidogrel, we set up the Two-Year ClOpidOgrel Need (TYCOON) registry and prospectively investigated the impact on very late thrombosis of 12- versus 24-month dual antiplatelet regimens in an unselected population. The registry enrolled 897 consecutive patients who underwent PCI with stenting from January 1, 2003, to December 31, 2004, and had dual antiplatelet therapy. All patients had a 4-year clinical follow-up. In the 447 patients with DES implantation, the dual antiplatelet regimen after PCI was given for 12 months in the 173 patients treated in 2003 (12-month group) and for 24 months in the 274 patients treated in 2004 (24-month group). Comparison between groups did not reveal any significant difference in baseline clinical characteristics, angiographic and procedural features, and major adverse cardiac events. During follow-up, there were 5 cases of stent thrombosis after PCI in the 12-month DES group and 1 case in the 24-month DES group (p = 0.02). Specifically, there were 2 cases of subacute thrombosis (1 in each group), no case of late thrombosis, and 4 cases of very late thrombosis occurring at 13, 15, 17, and 23 months after DES implantation in the 12-month group only. In conclusion, a 2-year dual antiplatelet regimen with aspirin and clopidogrel can prevent the occurrence of very late stent thrombosis after PCI with DESs.

Next generation drug-eluting stents: focus on bioabsorbable platforms and polymers

The success of drug-eluting stents in preventing restenosis has shifted the focus of new stent development toward enhancing long term safety and efficacy of these devices, while simultaneously eliminating the need for indefinite dual antiplatelet therapy. A technical advance fulfilling these aims would hold tremendous potential to reduce morbidity, mortality and economic costs associated with the percutaneous treatment of coronary artery disease. An attractive approach is the use of bioabsorbable stent designs. These may include stents with different bioabsorbable drugs, bioabsorbable polymers or even bioabsorbable metallic backbones. A device that could achieve excellent acute and long-term results, but disappear completely within months (thereby avoiding the need for prolonged dual antiplatelet therapy), would be a tremendous advance. Too good to be true? We explore here the scientific rationale and prospects for success with this exciting concept.

Clinical impact of sirolimus-eluting stent in ST-segment elevation myocardial infarction: a meta-analysis of randomized clinical trials

OBJECTIVES

To evaluate outcome of patients undergoing sirolimus-eluting stent (SES) as compared to bare-metal stent (BMS) implantation during primary angioplasty for ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

The role of SES in primary percutaneous coronary intervention setting is still debated.

METHODS

We searched Medline, EMBASE, CENTRAL, scientific session abstracts, and relevant Websites for studies in any language, from the inception of each database until October 2008. Only randomized clinical trials with a mean follow-up period >6 months and sample size >100 patients were included. Primary endpoint for efficacy was target-vessel revascularization (TVR) and primary endpoint for safety was stent thrombosis. Secondary endpoints were cardiac death and recurrent myocardial infarction (MI).

RESULTS

Six trials were included in the meta-analysis, including 2,381 patients (1,192 randomized to SES and 1,189 to BMS). Up to 12-month follow-up, TVR was significantly lower in patients treated with SES as compared to patients treated with BMS (4.53% vs. 12.53%, respectively; odds ratio [OR] 0.33; 95% confidence interval [CI] 0.24-0.46; P < 0.00001). There were no significant differences in the incidence of stent thrombosis (3.02% vs. 3.70%, OR = 0.81 [95% CI, 0.52-1.27], P = 0.81), cardiac death (2.77% vs. 3.28%, OR = 0.84 [95% CI, 0.52-1.35], P = 0.47), and recurrent MI (2.94% vs. 4.04%, OR = 0.71 [95% CI, 0.45-1.11], P = 0.13) between the two groups.

CONCLUSION

SES significantly reduces TVR rates as compared to BMS in STEMI patients up to 1 year follow-up. Further studies with larger population and longer follow-up time are needed to confirm our findings.

Combining antiplatelet and anticoagulant therapies

Antiplatelet therapy is the cornerstone for both primary and secondary prevention therapies for ischemic events resulting from coronary atherosclerotic disease. Dual antiplatelet therapy (aspirin plus a thienopyridine, usually clopidogrel) has assumed a central role in the treatment of acute coronary syndromes and after coronary stent deployment. In addition to antiplatelet therapy, anticoagulant therapy might be indicated for stroke prevention in a variety of conditions that include atrial fibrillation, profound left ventricular dysfunction, and after mechanical prosthetic heart valve replacement. For this reason, the use of triple antithrombotic therapy (a dual antiplatelet regimen plus warfarin) is expected to become more prominent, given an aging patient population. But although triple therapy can prevent both thromboembolism and stent thrombosis, it is also associated with significant bleeding hazards. Furthermore, when bleeding events do occur, the challenge of balancing the risk of stent thrombosis or stroke and the need for hemostasis requires considerable expertise. It is both prudent and timely to review treatment strategies that employ combinations of antiplatelet and anticoagulant therapies as well as strategies aimed at reducing bleeding risk in patients treated with these therapies.

Safety and efficacy of drug-eluting and bare metal stents: comprehensive meta-analysis of randomized trials and observational studies

BACKGROUND

The safety and efficacy of drug-eluting stents (DES) among more generalized "real-world" patients than those enrolled in pivotal randomized controlled trials (RCTs) are controversial. We sought to perform a meta-analysis of DES studies to estimate the relative impact of DES versus bare metal stents (BMS) on safety and efficacy end points, particularly for non-Food and Drug Administration-labeled indications.

METHODS AND RESULTS

Comparative DES versus BMS studies published or presented through February 2008 with > or =100 total patients and reporting mortality data with cumulative follow-up of > or =1 year were identified. Data were abstracted from studies comparing DES with BMS; original source data were used when available. Data from 9470 patients in 22 RCTs and from 182 901 patients in 34 observational studies were included. RCT and observational data were analyzed separately. In RCTs, DES (compared with BMS) were associated with no detectable differences in overall mortality (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.81 to 1.15; P=0.72) or myocardial infarction (HR, 0.95; 95% CI, 0.79 to 1.13; P=0.54), with a significant 55% reduction in target vessel revascularization (HR, 0.45; 95% CI, 0.37 to 0.54; P<0.0001); point estimates were slightly lower in off-label compared with on-label analyses. In observational studies, DES were associated with significant reductions in mortality (HR, 0.78; 95% CI, 0.71 to 0.86), myocardial infarction (HR, 0.87; 95% CI, 0.78 to 0.97), and target vessel revascularization (HR, 0.54; 95% CI, 0.48 to 0.61) compared with BMS.

CONCLUSIONS

In RCTs, no significant differences were observed in the long-term rates of death or myocardial infarction after DES or BMS use for either off-label or on-label indications. In real-world nonrandomized observational studies with greater numbers of patients but the admitted potential for selection bias and residual confounding, DES use was associated with reduced death and myocardial infarction. Both RCTs and observational studies demonstrated marked and comparable reductions in target vessel revascularization with DES compared with BMS. These data in aggregate suggest that DES are safe and efficacious in both on-label and off-label use but highlight differences between RCT and observational data comparing DES and BMS.

3-year follow-up of the SISR (Sirolimus-Eluting Stents Versus Vascular Brachytherapy for In-Stent Restenosis) trial

OBJECTIVES

The aim of this study was to evaluate long-term outcome of patients treated for in-stent restenosis of bare-metal stents (BMS).

BACKGROUND

Treatment of restenosis of BMS is characterized by high recurrence rates. Vascular brachytherapy (VBT) improved outcome although late catch-up events were documented. Drug-eluting stents tested against VBT in this setting were found superior for at least the first year; superiority at longer follow-up is uncertain.

METHODS

We evaluated 3-year outcome of the multicenter SISR (Sirolimus-Eluting Stents Versus Vascular Brachytherapy for In-Stent Restenosis) trial, which randomized patients with restenosis of BMS to either a sirolimus-eluting stents (SES) or VBT.

RESULTS

Target vessel failure (cardiac death, infarction, or target vessel revascularization [TVR]) at 9 months as previously reported was significantly improved with SES. Kaplan-Meier analysis at 3 years documented that survival free from target lesion revascularization (TLR) and TVR continues to be significantly improved with SES: freedom from TLR 81.0% versus 71.6% (log-rank p = 0.018), and TVR 78.2% versus 68.8% (log-rank p = 0.022), SES versus VBT. At 3 years, target vessel failure and major adverse cardiac events (death, infarction, emergency coronary artery bypass grafting, or repeat TLR) remained improved with SES, but did not reach statistical significance. There was no statistically significant difference in definite or probable stent thrombosis (3.5% for SES, 2.4% for VBT; p = 0.758).

CONCLUSIONS

At 3 years of follow-up, after treatment of in-stent restenosis of BMS, patients treated with SES have improved survival free of TLR and TVR compared with patients treated with VBT. Stent thrombosis rates are not different between the 2 groups but are higher than reported in trials of treatment of de novo lesions.

Bleeding, blood transfusion, and increased mortality after percutaneous coronary intervention: implications for contemporary practice

Advances in percutaneous coronary intervention (PCI) during the past decade have led to more widespread use of these procedures in older and sicker patients. Refinement of periprocedural antithrombotic therapy has played a particularly important role in reducing ischemic complications to very low levels in routine practice. Although the use of more powerful antiplatelet agents has been associated with increased risk of bleeding (especially among the elderly and patients with serious comorbidities), such complications have traditionally been viewed as benign in nature. Recent studies, however, have identified major bleeding after PCI as an important predictor of increased mortality. Whether this relationship between bleeding and risk of death is cause-and-effect, or merely an association based on shared risk factors, remains unclear. In this review, we examine the basis for a possible causal link between post-PCI bleeding and subsequent mortality. Possible mechanisms underpinning such a link are discussed, including a potential adverse role for blood transfusion in this setting. A framework for further clinical evaluation of this issue is presented.

Comprehensive meta-analysis on drug-eluting stents versus bare-metal stents during extended follow-up

BACKGROUND

Several observational reports have documented both increased and decreased cardiac mortality or Q-wave myocardial infarction with drug-eluting stents compared with bare-metal stents.

METHODS

We sought to evaluate the safety and efficacy of drug-eluting stents compared with bare-metal stents early after intervention (<1 year) and late (>1 year) among a broad population of patients, using a meta-analysis of randomized clinical trials.

RESULTS

We identified 28 trials with a total of 10,727 patients and a mean follow-up of 29.6 months. For early outcomes (<1 year), all-cause mortality for drug-eluting stents versus bare-metal stents was 2.1% versus 2.4% (risk ratio [RR] 0.91, [95% confidence interval (CI), 0.70-1.18]; P=.47), non-Q-wave myocardial infarction was 3.3% versus 4.4% (RR 0.78 [95% CI, 0.61-1.00]; P=.055), target lesion revascularization was 5.8% versus 18.4% (RR 0.28 [95% CI, 0.21-0.38]; P <.001), and stent thrombosis was 1.1% versus 1.3% (RR 0.87 [95% CI, 0.60-1.26]; P=.47). For late outcomes (>1 year), all-cause mortality for drug-eluting stents versus bare-metal stents was 5.9% versus 5.7% (RR 1.03 [95% CI, 0.83-1.28]; P=.79), target lesion revascularization was 4.0% versus 3.3% (RR 1.22 [95% CI, 0.92-1.60]; P=.16), non-Q-wave myocardial infarction was 1.6% versus 1.2% (RR 1.36 [95% CI, 0.74-2.53]; P=.32) and stent thrombosis was 0.7% versus 0.1% (RR 4.57 [95% CI, 1.54-13.57]; P=.006).

CONCLUSIONS

There was no excess mortality with drug-eluting stents. Within 1 year, drug-eluting stents appear to be safe and efficacious with possibly decreased non-Q-wave myocardial infarction compared with bare-metal stents. After 1 year, drug-eluting stents still have similar mortality, despite increased stent thrombosis. The reduction in target lesion revascularization with drug-eluting stents mainly happens within 1 year, but is sustained thereafter.

Clopidogrel resistance "Live" - the risk of stent thrombosis should be evaluated before procedures

Every year, millions of people undergo percutaneous coronary intervention (PCI) with intracoronary stent implantation. A patient from the PRAGUE-8 trial (Optimal pre-PCI clopidogrel loading: 600 mg before every coronary angiography vs. 600 mg in the cath-lab only for PCI patients) is described who suffered from acute stent thrombosis. This patient did not have any relevant inhibition of platelet activation even after the 600 mg dose of clopidogrel. Dose uptitration would have been ineffective. New P2Y₁₂ receptor inhibitors are desperately needed. In the light of recently published data, the use of prasugrel may be considered as an alternative.

Long-term safety and efficacy of drug-eluting versus bare-metal stents in Sweden

BACKGROUND

The long-term safety and efficacy of drug-eluting coronary stents have been questioned.

METHODS

We evaluated 47,967 patients in Sweden who received a coronary stent and were entered into the Swedish Coronary Angiography and Angioplasty Registry between 2003 and 2006 and for whom complete follow-up data were available for 1 to 5 years (mean, 2.7). In the primary analysis, we compared patients who received one drug-eluting coronary stent (10,294 patients) with those who received one bare-metal stent (18,659), after adjustment for differences in clinical characteristics of the patients and characteristics of the vessels and lesions.

RESULTS

Analyses of outcome were based on 2380 deaths and 3198 myocardial infarctions. There was no overall difference between the group that received drug-eluting stents and the group that received bare-metal stents in the combined end point of death or myocardial infarction (relative risk with drug-eluting stents, 0.96; 95% confidence interval [CI], 0.89 to 1.03) or the individual end points of death (relative risk, 0.94; 95% CI, 0.85 to 1.05) and myocardial infarction (relative risk, 0.97; 95% CI, 0.88 to 1.06), and there was no significant difference in outcome among subgroups stratified according to the indication for stent implantation. Patients who received drug-eluting stents in 2003 had a significantly higher rate of late events than patients who received bare-metal stents in the same year, but we did not observe any difference in outcome among patients treated in later years. The average rate of restenosis during the first year was 3.0 events per 100 patient-years with drug-eluting stents versus 4.7 with bare-metal stents (adjusted relative risk, 0.43; 95% CI, 0.36 to 0.52); 39 patients would need to be treated with drug-eluting stents to prevent one case of restenosis. Among high-risk patients, the adjusted risk of restenosis was 74% lower with drug-eluting stents than with bare-metal stents, and only 10 lesions would need to be treated to prevent one case of restenosis.

CONCLUSIONS

As compared with bare-metal stents, drug-eluting stents are associated with a similar long-term incidence of death or myocardial infarction and provide a clinically important decrease in the rate of restenosis among high-risk patients.

Neointimal regression-induced incomplete coverage of a bare-metal stent in the left main trunk: serial angiographic and angioscopic evidence obtained by 5-year follow-up

Very late stent thrombosis (VLST), a rare complication of stenting, has been reported to develop more frequently at later than 1 year after the deployment of the drug-eluting stent (DES) compared with the bare-metal stent (BMS). However, the causes for the difference in the incidence remain unknown. Serial angioscopy on 1,591 and 1,952 days after BMS deployment in a Japanese male patient with acute myocardial infarction revealed incomplete neointimal coverage (INC) without the development of cardiovascular event. Therefore, the potential development of VLST remains undeniable in BMS-deployed patients who had INC.

Extended follow-up by serial angioscopic observation for bare-metal stents in native coronary arteries: from healing response to atherosclerotic transformation of neointima

BACKGROUND

Although coronary angiograms after bare-metal stent (BMS) implantation show late luminal narrowing beyond 4 years, the detailed changes inside the BMS have not yet been fully elucidated.

METHODS AND RESULTS

Serial angiographic and angioscopic examinations were performed immediately (baseline), 6 to 12 months (first follow-up), and >or=4 years (second follow-up) after stenting without target lesion revascularization in 26 segments of 26 patients who received BMS deployment for their native coronary arteries. Angioscopic observation showed atherosclerotic yellow plaque crushed out by stent struts in 22 patients (85%) and mural thrombus in 21 patients (81%) at baseline. At first follow-up, white neointimal hyperplasia was almost completely buried inside the struts, and both yellow plaque and thrombus had decreased in comparison with baseline (12% and 4%, respectively; P<0.001). The frequencies of yellow plaque and thrombus increased from the first to second follow-ups (58% and 31%, respectively; P<0.05). All of the yellow plaques in the second follow-up were located not exterior to the struts but protruding from the vessel wall into the lumen. Late luminal narrowing, defined as an increasing of percent diameter stenosis between the first and second follow-ups, was greater in segments with yellow plaque than in those without yellow plaque (18.4+/-17.3% versus 3.6+/-4.2%, respectively; P=0.011).

CONCLUSIONS

This angiographic and angioscopic study suggests that white neointima of the BMS may often change into yellow plaque over an extended period of time, and atherosclerotic progression inside the BMS may contribute to late luminal narrowing.

Effectiveness of primary percutaneous coronary interventions for stent thrombosis

There are very few (and conflicting) data about the effectiveness of primary percutaneous coronary interventions (PCIs) for stent thrombosis (ST) treatment. We sought to evaluate the prevalence, efficacy, and outcomes of primary PCI in patients with ST-elevation acute myocardial infarction (STEMI) due to ST in 2,464 consecutive patients treated by primary PCI. ST was the cause of STEMI in 67 patients (3%). Patients with ST showed a lower rate of significant collateral circulation (0% vs 6%, p = 0.034) and a higher peak creatine kinase value (2,678 +/- 3,221 vs 2,375 +/- 2,189 U/L, p = 0.003) compared with the other 2,397 patients with STEMI. PCI was successful in 64 patients (96%) in the ST group and consisted of additional stenting (78%) or only balloon angioplasty (22%). Abciximab and rheolytic thrombectomy were used in 75% and 31% of patients, respectively. Procedure (39 +/- 26 vs 32 +/- 19 minutes, p = 0.0001) and fluoroscopy (13 +/- 10 vs 10 +/- 8 minutes, p = 0.0001) times were longer, and contrast medium amount (221 +/- 89 vs 194 +/- 103 ml, p = 0.034) larger in patients with ST compared with patients with de novo STEMI. Six-month death (12% vs 8%, p = 0.216) and nonfatal reinfarction (10% vs 1%, p = 0.0001) rates were higher in patients with ST compared with those without. At 6-month angiographic follow-up (n = 1,843 of 2,269), the restenosis/reocclusion rate was 54% versus 17% (p = 0.0001) in patients with and without ST. In conclusion, the prevalence of primary PCI for ST is low. Additional stenting with or without thrombectomy is effective in restoring vessel patency in patients with ST, but restenosis and reocclusion are frequent. ST treated with successful PCI is associated with a large infarct and poor outcome.

Two-year clinical outcome with drug-eluting stents versus bare-metal stents in a real-world registry of unprotected left main coronary artery stenosis from the Italian Society of Invasive Cardiology

Data are limited about the relative efficacy of drug-eluting stents (DESs) versus bare-metal stents (BMSs) for the treatment of unprotected left main coronary artery (ULMCA) stenosis. The survey promoted by the Italian Society of Invasive Cardiology on ULMCA stenosis was an observational study involving 19 high-volume Italian centers of patients with ULMCA stenosis treated using percutaneous coronary intervention (PCI). From January 2002 to December 2006, of 1,453 patients identified with ULMCA stenosis treated with PCI, 1,111 were treated with DESs and 342 were treated with BMSs. During a 2-year follow-up, risk-adjusted survival free from cardiac death was significantly higher in patients treated with DESs than in those treated with BMSs. The propensity-adjusted hazard ratio for risk of 2-year cardiac mortality after DES versus BMS implantation was 0.49 (95% confidence interval 0.32 to 0.77). The benefit of DESs in reducing cardiac mortality was obtained in the period from 3 to 6 months and maintained up to 2 years. In conclusion, for patients with ULMCA stenosis undergoing PCI, DES implantation was associated with higher adjusted rates of 2-year survival free from cardiac death. The benefit of DESs in reducing cardiac mortality was obtained in the period in which clinical manifestations of restenosis usually peak.

Drug-Eluting or Bare-Metal Stenting in Patients With Diabetes Mellitus

Background— Patients with diabetes mellitus (DM) are at high risk for restenosis, myocardial infarction, and cardiac mortality after coronary stenting, and the long-term safety of drug-eluting stents (DES) relative to bare-metal stents (BMS) in DM is uncertain. We report on a large consecutive series of patients with DM followed up for 3 years after DES and BMS from a regional contemporary US practice with mandatory reporting.

Methods and Results— All adults with DM undergoing percutaneous coronary intervention with stenting between April 1, 2003, and September 30, 2004, at all acute care nonfederal hospitals in Massachusetts were identified from a mandatory state database. According to index admission stent type, patients were classified as DES treated if all stents were drug eluting and as BMS treated if all stents were bare metal; patients treated with both types of stents were excluded from the primary analysis. Mortality rates were obtained from vital statistics records, and myocardial infarction and revascularization rates were obtained from the state database with complete 3 years of follow-up on the entire cohort. Risk-adjusted mortality, myocardial infarction, and revascularization differences (DES−BMS) were estimated with propensity-score matching based on clinical, procedural, hospital, and insurance information collected at the index admission. DM was present in 5051 patients (29% of the population) treated with DES or BMS during the study. Patients with DM were more likely to receive DES than BMS (66.1% versus 33.9%; P <0.001). The unadjusted cumulative incidence of mortality at 3 years was 14.4% in DES versus 22.2% in BMS ( P <0.001). Based on propensity-score analysis of 1:1 matched DES versus BMS patients (1476 DES:1476 BMS), the risk-adjusted mortality, MI, and target vessel revascularization rates at 3 years were 17.5% versus 20.7% (risk difference, −3.2%; 95% confidence interval, −6.0 to −0.4; P =0.02), 13.8% versus 16.9% (−3.0%; 95% confidence interval, −5.6 to 0.5; P =0.02), and 18.4% versus 23.7% (−5.4%; confidence interval, −8.3 to −2.4; P <0.001), respectively.

Conclusions— In a real-world diabetic patient population with mandatory reporting and follow-up, DES were associated with reduced mortality, myocardial infarction, and revascularization rates at long-term follow-up compared with BMS.

Long-term clinical outcomes after drug-eluting and bare-metal stenting in Massachusetts

BACKGROUND

Drug-eluting stents (DES) reduce the need for repeat revascularization, but their long-term safety relative to that of bare-metal stents (BMS) in general use remains uncertain. We sought to compare the clinical outcome of patients treated with DES with that of BMS.

METHODS AND RESULTS

All adults undergoing percutaneous coronary intervention with stenting between April 1, 2003, and September 30, 2004, at non-US government hospitals in Massachusetts were identified from a mandatory state database. Patients were classified from the index admission according to stent types used. Clinical and procedural risk factors were collected prospectively. Risk-adjusted mortality, myocardial infarction, and revascularization rate differences (DES-BMS) were estimated through propensity score matching without replacement. A total of 11 556 patients were treated with DES, and 6237 were treated with BMS, with unadjusted 2-year mortality rates of 7.0% and 12.6%, respectively (P<0.0001). In 5549 DES patients matched to 5549 BMS patients, 2-year risk-adjusted mortality rates were 9.8% and 12.0%, respectively (P=0.0002), whereas the respective rates for myocardial infarction and target-vessel revascularization were 8.3% versus 10.3% (P=0.0005) and 11.0% versus 16.8% (P<0.0001).

CONCLUSIONS

DES treatment was associated with lower rates of mortality, myocardial infarction, and target-vessel revascularization than BMS treatment in similar patients in a matched population-based study. Comprehensive follow-up in this inclusive population is warranted to identify whether similar safety and efficacy remain beyond 2 years.

Drug-eluting or bare-metal stents for acute myocardial infarction

BACKGROUND

Studies comparing percutaneous coronary intervention (PCI) with drug-eluting and bare-metal coronary stents in acute myocardial infarction have been limited in size and duration.

METHODS

We identified all adults undergoing PCI with stenting for acute myocardial infarction between April 1, 2003, and September 30, 2004, at any acute care, nonfederal hospital in Massachusetts with the use of a state-mandated database of PCI procedures. We performed propensity-score matching on three groups of patients: all patients with acute myocardial infarction, all those with acute myocardial infarction with ST-segment elevation, and all those with acute myocardial infarction without ST-segment elevation. Propensity-score analyses were based on clinical, procedural, hospital, and insurance information collected at the time of the index procedure. Differences in the risk of death between patients receiving drug-eluting stents and those receiving bare-metal stents were determined from vital-statistics records.

RESULTS

A total of 7217 patients were treated for acute myocardial infarction (4016 with drug-eluting stents and 3201 with bare-metal stents). According to analysis of matched pairs, the 2-year, risk-adjusted mortality rates were lower for drug-eluting stents than for bare-metal stents among all patients with myocardial infarction (10.7% vs. 12.8%, P=0.02), among patients with myocardial infarction with ST-segment elevation (8.5% vs. 11.6%, P=0.008), and among patients with myocardial infarction without ST-segment elevation (12.8% vs. 15.6%, P=0.04). The 2-year, risk-adjusted rates of recurrent myocardial infarction were reduced in patients with myocardial infarction without ST-segment elevation who were treated with drug-eluting stents, and repeat revascularization rates were significantly reduced with the use of drug-eluting stents as compared with bare-metal stents in all groups.

CONCLUSIONS

In patients presenting with acute myocardial infarction, treatment with drug-eluting stents is associated with decreased 2-year mortality rates and a reduction in the need for repeat revascularization procedures as compared with treatment with bare-metal stents.

Long-term impact of drug-eluting stents versus bare-metal stents on all-cause mortality

OBJECTIVES

Our purpose was to examine the incidence of all-cause mortality among drug-eluting stents (DES) and bare-metal stents (BMS) while adjusting for many confounding factors generally not considered in prior studies.

BACKGROUND

DES use in the U.S. declined by up to 50% in recent years, primarily due to concerns about late stent thrombosis and possibly increased mortality. However, recent data suggest that DES are as safe as BMS and may actually be associated with a lower incidence of myocardial infarction and mortality.

METHODS

All patients undergoing percutaneous coronary intervention with a DES or BMS alone from March 1, 2003, to June 30, 2007, at a tertiary care center were assessed. Multivariable Cox proportional hazards modeling was performed for overall and propensity-matched patients. Socioeconomic status was calculated using U.S. Census 2000 data. The primary end point was all-cause mortality.

RESULTS

There were a total of 832 deaths over a 4.5-year interval among 8,032 patients. Of these, 6,053 received a DES and 1,983 patients had a BMS. All-cause mortality was significantly lower in unadjusted and adjusted Cox proportional models with DES (hazard ratio: 0.62, 95% confidence interval: 0.53 to 0.73; p < 0.001). Similarly, in the propensity-matched group, DES remained associated with lower mortality compared with BMS (adjusted hazard ratio: 0.54, 95% confidence interval: 0.45 to 0.66; p < 0.001).

CONCLUSIONS

DES were associated with lower mortality in this "real-world" setting. However, despite multiple adjustments, potential confounding may still play a role.

Drug-eluting stent thrombosis

Stent thrombosis is a rare complication following stent implantation; if it occurs, however, it is associated with a high morbidity and mortality. Despite reduced rates of restenosis, drug-eluting stents (DES) have not reduced the incidence of stent thrombosis as compared with bare-metal stents (BMS). Patient-, lesion-, and procedure-related factors as well as thrombogenicity of the stent itself are involved in the pathogenesis of stent thrombosis. Furthermore, early cessation of dual antiplatelet therapy correlates with an increased risk of stent thrombosis. This review focuses on clinical evidence and pathophysiological mechanisms of stent thrombosis with DES, particularly highlighting prothrombotic effects of the stent itself.

Drug eluting and bare metal stents in people with and without diabetes: collaborative network meta-analysis

OBJECTIVE

To compare the effectiveness and safety of three types of stents (sirolimus eluting, paclitaxel eluting, and bare metal) in people with and without diabetes mellitus.

DESIGN

Collaborative network meta-analysis.

DATA SOURCES

Electronic databases (Medline, Embase, the Cochrane Central Register of Controlled Trials), relevant websites, reference lists, conference abstracts, reviews, book chapters, and proceedings of advisory panels for the US Food and Drug Administration. Manufacturers and trialists provided additional data.

REVIEW METHODS

Network meta-analysis with a mixed treatment comparison method to combine direct within trial comparisons between stents with indirect evidence from other trials while maintaining randomisation. Overall mortality was the primary safety end point, target lesion revascularisation the effectiveness end point.

RESULTS

35 trials in 3852 people with diabetes and 10,947 people without diabetes contributed to the analyses. Inconsistency of the network was substantial for overall mortality in people with diabetes and seemed to be related to the duration of dual antiplatelet therapy (P value for interaction 0.02). Restricting the analysis to trials with a duration of dual antiplatelet therapy of six months or more, inconsistency was reduced considerably and hazard ratios for overall mortality were near one for all comparisons in people with diabetes: sirolimus eluting stents compared with bare metal stents 0.88 (95% credibility interval 0.55 to 1.30), paclitaxel eluting stents compared with bare metal stents 0.91 (0.60 to 1.38), and sirolimus eluting stents compared with paclitaxel eluting stents 0.95 (0.63 to 1.43). In people without diabetes, hazard ratios were unaffected by the restriction. Both drug eluting stents were associated with a decrease in revascularisation rates compared with bare metal stents in people both with and without diabetes.

CONCLUSION

In trials that specified a duration of dual antiplatelet therapy of six months or more after stent implantation, drug eluting stents seemed safe and effective in people both with and without diabetes.

Compartmentation and compartment-specific regulation of PDE5 by protein kinase G allows selective cGMP-mediated regulation of platelet functions

It is generally accepted that nitric oxide (NO) donors, such as sodium nitroprusside (SNP), or phosphodiesterase 5 (PDE5) inhibitors, including sildenafil, each impact human platelet function. Although a strong correlation exists between the actions of NO donors in platelets and their impact on cGMP, agents such as sildenafil act without increasing global intra-platelet cGMP levels. This study was undertaken to identify how PDE5 inhibitors might act without increasing cGMP. Our data identify PDE5 as an integral component of a protein kinase G1beta (PKG1beta)-containing signaling complex, reported previously to coordinate cGMP-mediated inhibition of inositol-1, 4, 5-trisphosphate receptor type 1 (IP(3)R1)-mediated Ca(2+)-release. PKG1beta and PDE5 did not interact in subcellular fractions devoid of IP(3)R1 and were not recruited to IP(3)R1-enriched membranes in response to cGMP-elevating agents. Activation of platelet PKG promoted phosphorylation and activation of the PDE5 fraction tethered to the IP(3)R1-PKG complex, an effect not observed for the nontethered PDE5. Based on these findings, we elaborate a model in which PKG selectively activates PDE5 within a defined microdomain in platelets and propose that this mechanism allows spatial and temporal regulation of cGMP signaling in these cells. Recent reports indicate that sildenafil might prove useful in limiting in-stent thrombosis and the thrombotic events associated with the acute coronary syndromes (ACS), situations poorly regulated with currently available therapeutics. We submit that our findings may define a molecular mechanism by which PDE5 inhibition can differentially impact selected cellular functions of platelets, and perhaps of other cell types.

Delayed arterial healing and increased late stent thrombosis at culprit sites after drug-eluting stent placement for acute myocardial infarction patients: an autopsy study

BACKGROUND

The long-term safety of drug-eluting stents (DES) for acute myocardial infarction (AMI) remains uncertain. Using autopsy data, we evaluated the pathological responses of the stented segment in patients treated with DES for AMI and compared with patients with stable angina.

METHODS AND RESULTS

From the CVPath Registry of 138 DES autopsies, we identified 25 patients who presented with AMI and had an underlying necrotic core with a ruptured fibrous cap. Twenty-six patients who had stable angina with thick-cap fibroatheroma treated by DES were selected as controls. Histomorphometric analysis was performed in patients with >30-day stent duration. We compared the response to stenting at the culprit site in these 2 groups and to nonculprit sites within each stent. Late stent thrombosis was significantly less frequent in stable (11%) than in AMI (41%; P=0.04) patients. Although neointimal thickness in the AMI culprit site was significantly less (median, 0.04 mm; interquartile range [IQR], 0.02 to 0.09 mm), the prevalence of uncovered struts (49%; IQR, 16% to 96%), fibrin deposition (63+/-28%), and inflammation (35%; IQR, 27% to 49%) were significantly greater compared with the culprit site in stable patients (neointimal thickness: 0.11 mm [IQR, 0.07 to 0.21 mm], P=0.008; uncovered struts: 9% [IQR, 0% to 39%], P=0.01; fibrin: 36+/-27%, P=0.008; inflammation, 17% [IQR, 7% to 25%], P=0.003) and the nonculprit site within each stent.

CONCLUSIONS

Vessel healing at the culprit site in AMI patients treated with DES is substantially delayed compared with the culprit site in patients receiving DES for stable angina, emphasizing the importance of underlying plaque morphology in the arterial response to DES. Our data suggest an increased risk of thrombotic complications in patients treated with DES for AMI.

Catheter-Based Treatment of Coronary Artery Disease

September 2007 marked the 30-year anniversary of the first human percutaneous coronary intervention, an index event that changed the course of modern-day cardiovascular care. Before that first procedure, adult invasive cardiology focused on diagnostic angiography as well as hemodynamic assessment of structural heart disease. Since that initial procedure, percutaneous coronary intervention has become the most frequently performed coronary revascularization procedure worldwide. Several factors have been responsible for this dramatic paradigm shift, the most prominent being identification of opportunities for technical improvement and the application of innovation and investigation in concert with colleagues, professional societies, and industry. These approaches will continue to be of paramount importance as new technologies are brought to bear on an increasingly broader group of patients with cardiovascular disease.