Formation of Calcified Nodule as a Cause of Early In-Stent Restenosis in Patients Undergoing Dialysis

Background Dialysis is an independent risk factor for in-stent restenosis (ISR) after stent implantation in coronary arteries. However, the characteristics of ISR in patients undergoing dialysis remain unclear, as there are no histological studies evaluating the causes of this condition. The aim of the present study was to investigate the causes of ISR between patients who are undergoing dialysis and those who are not by evaluating tissues obtained from ISR lesions using directional coronary atherectomy. Methods and Results A total of 29 ISR lesions from 29 patients included in a multicenter directional coronary atherectomy registry of 128 patients were selected for analysis and divided into a dialysis group (n=8) and a nondialysis group (n=21). Histopathological evaluation demonstrated that an in-stent calcified nodule was a major histological characteristic of ISR lesions in the dialysis group and the prevalence of an in-stent calcified nodule was significantly higher in the dialysis group compared with the nondialysis group (75% versus 5%, respectively; P<0.01). On the other hand, the prevalence of an in-stent lipid-rich plaque was significantly lower in the dialysis group compared with the nondialysis group (0% versus 43%, respectively; P=0.03). In all cases with an in-stent calcified nodule, the underlying calcification before stent implantation was moderate to severe. When tissue characteristics were stratified according to duration post-stent implantation, an in-stent calcified nodule in the dialysis group was mainly observed within 1 year after stent implantation. Conclusions In-stent calcified nodules are a common cause of ISR in patients undergoing dialysis and are observed within 1 year after stent implantation, suggesting different causes of ISR between patients undergoing dialysis and those who are not.

New Regulatory Framework for Medical Devices in Japan: Current Regulatory Considerations Regarding Clinical Studies

In Japan, a recent issue that required an urgent response was the streamlining of regulations concerning clinical trials of medical devices. On July 31, 2017, the Ministry of Health, Labour and Welfare enacted a new regulatory framework called the fast-break scheme for innovative medical devices aiming to expedite patient access while reducing the premarket regulatory burden of clinical trials and enhancing postmarketing commitments. The new framework is expected to provide greater benefits to patients who require access to new medical devices and to companies via improved transparency and predictability, as well as to reduce the social and medical cost incurred for medical innovation.

Five-year clinical outcomes of everolimus-eluting stents from the post marketing study of CoCr-EES (XIENCE V/PROMUS) in Japan

The Cobalt Chromium Everolimus-Eluting Stent (CoCr-EES) Post Marketing Surveillance (PMS) Japan study is a prospective multicenter registry designed to evaluate the safety and efficacy of XIENCE V/PROMUS everolimus-eluting stents in routine clinical practice at 47 centers representative of the clinical environment in Japan. We enrolled 2010 consecutive patients (2649 lesions) who underwent percutaneous coronary intervention using CoCr-EES. Clinical outcomes were evaluated through 5 years. Mean age was 68.8 years, 41.9% had diabetes, 4.9% received hemodialysis. Five-year clinical follow up was available for 1704 (84.8%) patients. Major adverse cardiovascular events (MACE) occurred in 10.7% of patients, including cardiac death (3.8%), myocardial infarction (1.8%), and clinically driven target lesion revascularization (TLR) (6.0%). Beyond 1 year, annual incidence of clinically driven TLR was 0.5-0.8%. Definite or probable stent thrombosis occurred in 9 (0.5%) patients at 5 years. After 1 year, definite stent thrombosis occurred in only 1 patient. Significant predictors for MACE were dialysis (ODDs ratio 4.58, 95% CI 2.75-7.64), prior cardiac intervention (ODDs ratio 2.47, 95% CI 1.75-3.49), total stent length (ODDs ratio 1.01, 95% CI 1.01-1.02), and number of diseased vessels (ODDs ratio 1.66, 95% CI 1.08-2.55). Five-year clinical outcomes from the CoCr-EES PMS Japan study demonstrated a low incidence of clinical events in the daily practice up to 5 years.Clinical Trial Registration Information: https://clinicaltrials.gov/ct2/show/NCT01086228 .

Validating Utility of Dual Antiplatelet Therapy Score in a Large Pooled Cohort From 3 Japanese Percutaneous Coronary Intervention Studies

Background:

The dual antiplatelet therapy (DAPT) score was developed to estimate ischemic and bleeding risks from the DAPT study. However, few studies validated its utility externally. We sought to validate the utility of the DAPT score in the Japanese population.

Methods:

In a pooled cohort of 3 studies conducted in Japan (the CREDO-Kyoto [Coronary Revascularization Demonstrating Outcome Study in Kyoto] Registry Cohort-2, RESET [Randomized Evaluation of Sirolimus-Eluting Versus Everolimus-Eluting Stent Trial], and NEXT [NOBORI Biolimus-Eluting Versus XIENCE/PROMUS Everolimus-Eluting Stent Trial]), we compared risks for ischemic and bleeding events from 13 to 36 months after percutaneous coronary intervention among patients with a DAPT score ≥2 (high DS) and a DAPT score <2 (low DS).

Results:

Among 12 223 patients receiving drug-eluting stents who were free from ischemic or bleeding events at 13 months after percutaneous coronary intervention, 3944 patients had high DS and 8279 had low DS. The cumulative incidence of primary ischemic end point (myocardial infarction/stent thrombosis) was significantly higher in high DS than in low DS (1.5% versus 0.9%, P =0.002), whereas the cumulative incidence of primary bleeding end point (GUSTO moderate/severe) tended to be lower in high DS than in low DS (2.1% versus 2.7%, P =0.07). The cumulative incidences of cardiac death, myocardial infarction, and stent thrombosis were also significantly higher in high DS than in low DS (2.0% versus 1.4%, P =0.03; 1.5% versus 0.8%, P =0.002; 0.7% versus 0.3%, P <0.001, respectively), whereas the cumulative incidences of noncardiac death and GUSTO severe bleeding were significantly lower in high DS than in low DS (2.4% versus 3.9%, P <0.001; 1.0% versus 1.6%, P =0.03, respectively).

Conclusions:

In the current population, the DAPT score successfully stratified ischemic and bleeding risks, although the ischemic event rate was remarkably low even in high DS. Further studies would be warranted to evaluate the utility of prolonged DAPT guided by the DAPT score.

Midterm angiographic outcomes with sirolimus- and everolimus-eluting stents for small vessels in diabetic patients: propensity-score-matched comparisons in three different vessel diameters

We conducted propensity-score-matched comparisons of midterm angiographic follow-up outcomes of sirolimus- versus everolimus-eluting stents (SES, EES) after elective placements for de novo coronary stenosis in small vessels (SV) in patients with diabetes mellitus (DM), because the angiographic efficacy of EES over SES for those cohorts remained unclear. The study was a non-randomized, retrospective, lesion-based, multicenter study, examining lesions followed up angiographically within 550 days, extracted from the unified database of 6 institutes. The endpoint (binary restenosis) was defined as the percentage of subjects having >50% diameter stenosis at follow-up. Propensity-score-matched analyses were conducted in 3 different vessel-size cohorts, defined by a preprocedural reference diameter (RD) <2.10, <2.35, and <2.60 mm, yielding group sizes of n = 107, 183, and 312 baseline-adjusted lesions in each of the 2 stent arms. The frequency of binary restenosis decreased significantly with increasing vessel size, at 16.8, 12.6, and 12.2%, in the SES group. However, it remained almost the same across vessel-size groups in the EES group (8.0, 6.0, and 7.5%). The p values for the significance of the differences in binary restenosis between EES and SES in each vessel size increased with the decrease in vessel size [p = 0.002, 0.040, and 0.063 (the last still nearly significant)]. Thus, in patients with DM, EES showed increasingly superior efficacy over SES for SV stenosis as the vessel size became smaller, i.e., the risk for binary restenosis became greater.

Three-Year Clinical Outcomes of Everolimus-Eluting Stents From the Post-Marketing Surveillance Study of Cobalt-Chromium Everolimus-Eluting Stent (XIENCE V/PROMUS) in Japan

BACKGROUND

The Cobalt-Chromium Everolimus-Eluting Stent (CoCr-EES) Post-marketing Surveillance (PMS) is a prospective multicenter registry designed to evaluate the safety and efficacy of XIENCE V/PROMUS everolimus-eluting stents in routine clinical practice at 47 centers representative of the clinical environment in Japan.

METHODS AND RESULTS

We enrolled 2,010 consecutive patients (2,649 lesions) who underwent PCI using CoCr-EES. Clinical outcomes were evaluated for up to 3 years. Clinical follow-up was available in 1,930 patients (96%) at 3 years. Major adverse cardiovascular events (MACE) occurred in 6.8% of patients, including cardiac death (1.7%), myocardial infarction (1.5%), and clinically driven target lesion revascularization (CD-TLR, 4.2%). Late CD-TLR rate was 0.8% from 1 to 2 years, and 0.5% from 2 to 3 years. Definite or probable stent thrombosis occurred in 7 patients (0.3%) up to 1 year. There was no very late definite or probable stent thrombosis from 1 to 3 years. Significant independent predictors for MACE were hemodialysis, prior coronary intervention, triple-vessel coronary artery disease, and age >70 years.

CONCLUSIONS

Three-year clinical outcomes from the CoCr-EES PMS demonstrated a low incidence of clinical events. There was no major concern about very late stent thrombosis or late catch-up phenomenon in patients treated with EES in routine clinical practice in Japan.

Usefulness of Everolimus-Eluting Coronary Stent Implantation in Patients on Maintenance Hemodialysis

The outcomes of second-generation drug-eluting stent (DES) are unknown in patients on maintenance hemodialysis (HD) although HD has been reported as a strong predictor of adverse outcome after the first-generation DES implantation. The OUCH-PRO Study is a prospective multicenter single-arm registry design to study clinical and angiographic outcomes after everolimus-eluting stent (EES). Patients who underwent maintenance HD were prospectively enrolled at the time of elective coronary intervention using EES. Quantitative coronary angiography was performed in an independent core laboratory. The primary end point was the occurrence of target vessel failure (TVF) defined as cardiac death, myocardial infarction (MI), and target vessel revascularization at 1 year. A total of 123 patients were enrolled and 161 EES were implanted. The TVF rate at 1 year was 18% (4% cardiac death, 0% MI, 17% target vessel revascularization). No stent thrombosis was documented. Other clinical events at 1 year were 3% noncardiac death, 3% stroke, and 9% non-target-vessel revascularization. Late lumen loss in stent was 0.37 ± 0.63 mm at 8 months. In conclusion, EES had a high TVF rate and great late lumen loss in patients on HD compared with previous huge EES data in non-HD patients.

Adherence to dual antiplatelet therapy after coronary stenting: a systematic review

BACKGROUND

Adherence to dual antiplatelet therapy (DAPT) is critical after coronary stenting. Although adherence rates are frequently assessed in clinical trials, adherence rates in the unselected population recommended for treatment but beyond clinical trials are largely unknown. Therefore, we performed a systematic review of published observational studies to describe rates of DAPT adherence, trends in DAPT use over time, and patient-level factors associated with nonadherence.

HYPOTHESIS

DAPT adherence declines with increasing time after drug-eluting stent implantation.

METHODS

PubMed, Cumulative Index to Nursing and Allied Health Literature, Embase, and Web of Knowledge were searched through November 20, 2012 for studies including patients receiving 1 or more drug-eluting stents and reporting the use of aspirin and/or thienopyridines, or assessing factors associated with nonadherence to DAPT after bare metal or drug-eluting stent placement.

RESULTS

We included 34 studies in the description of DAPT adherence and 11 studies in the description of factors associated with nonadherence. Adherence to DAPT and thienopyridines was high at 1 month but declined by 12 months. Aspirin adherence was at least 90% throughout. Factors associated with nonadherence included bleeding, lower education level, immigrant status, and lack of education regarding DAPT.

CONCLUSIONS

DAPT adherence is suboptimal at 12 months, and interventions to increase adherence should focus on reducing bleeding risk and improving communication between patients and physicians.

Long-term outcomes following off-label use of sirolimus-eluting stent

OBJECTIVE

To clarify the impact of off-label use of drug-eluting stent (DES) on 5-year outcomes.

BACKGROUND

Studies on the outcomes of on- vs. off-label use of DES have been limited by the duration of observation.

METHODS

We analyzed 1937 patients from a multicenter registry that includes 95% of patients with 5-year follow-up data. We defined 10 variables as off-label indications according to the manufacturer's instructions for use, and 1665 of 1937 patients (86.0%) met the criteria for at least 1 off-label indication.

RESULTS

At 5 years, there were no differences in the rates of death, myocardial infarction (MI), and stent thrombosis between off-label and on-label use. The frequency of major adverse cardiac events (MACE), target lesion revascularization (TLR), non-TL but target vessel revascularization (TVR), and target vessel failure were higher in the off-label only during the first year. Among the off-label, having 2 indications was associated with TVR hazard ratio (HR) 1.62; 95% confidence interval (95%CI), 1.09-2.36 and TLR (HR, 1.90; 95%CI, 1.30-2.85). Moreover, having ≥3 off-label indications increased the risk of MACE (HR, 1.70; 95% CI, 1.23-2.40) compared with on-label use. Thrombosis rates increased with the number of off-label indications; it was 0.32% with 1, 0.69% with 2, and 3.54% with ≥3 off-label indications (p<0.001). This trend was also seen with other outcomes, except for non-TL TVR. Patients with ≥3 off-label indications had a remarkably different clinical course.

CONCLUSION

Off-label use did not increase rates of death and MI as compared with on-label use, but the number of off-label indications influenced outcomes at 5 years.

Angiographic findings of everolimus-eluting as compared to sirolimus-eluting stents: angiographic sub-study from the Randomized Evaluation of Sirolimus-eluting versus Everolimus-eluting stent Trial (RESET)

Several recent randomized trials comparing everolimus-eluting stent (EES) and sirolimus-eluting stent (SES) reported similar clinical outcomes. This study was aimed to clarify the differences in the angiographic findings of EES as compared to SES. Randomized Evaluation of Sirolimus-eluting versus Everolimus-eluting stent Trial is a prospective multicenter randomized open-label trial comparing EES with SES in Japan. From February to July 2010, 3197 patients were randomly assigned to receive either EES or SES. Of these, angiographic sub-study enrolled 571 patients (EES 285 patients, SES 286 patients). Angiograms were assessed qualitatively and quantitatively at procedure and at 8-12 months in the independent core angiographic laboratory. Late loss of the proximal edges tended to be greater in the EES group than that in the SES group (0.12 ± 0.49 vs. 0.04 ± 0.43 mm, P = 0.05), although late loss in the other segments was similar between the 2 groups. Edge restenosis was mainly observed in EES group, whereas body restenosis was demonstrated in half of SES group. Stent fracture was observed only in the SES group (1.5 %), and peri-stent contrast staining (PSS) tended to be more frequently observed in the SES group than in the EES group (3.6 and 1.5 %, P = 0.18). Restenotic response in the proximal edge was more prominent in the EES group as compared to the SES group. Abnormal angiographic findings such as stent fracture and PSS tended to be more frequent in the SES group.

Long-term efficacy of sirolimus-eluting stent for small vessel disease--subanalysis of Cypher Stent Japan Post-Marketing Surveillance Registry

BACKGROUND

Percutaneous coronary intervention for lesions with small vessel diameter may have high event rates. Although drug-eluting stents reduce the risk of restenosis, the long-term efficacy of drug-eluting stent implantation in small vessels is unclear.

METHODS AND RESULTS

We reviewed the data of Cypher Stent Japan Post-Marketing Surveillance Registry including 2356 lesions of 1959 patients, and retrospectively investigated the angiographic outcomes at 8 months, and the clinical outcomes at 1800 days after sirolimus-eluting stent (SES) implantation in vessels with diameter less than 2.5mm (small vessel group) compared to that with diameter of 2.5mm or more (non-small vessel group). The rate of major adverse cardiac events (MACE) at 1800 days was slightly higher in the small vessel group than in the non-small vessel group, but not statistically significant (24.4% vs 21.0%, p=0.086). The rate of target lesion revascularization was higher in the small vessel group than in the non-small vessel group (10.2% vs 6.4%, p=0.004). The rate of stent thrombosis was almost the same in the two groups. Multivariate Cox hazard model analysis revealed that a vessel diameter less than 2.5mm was not an independent risk factor for MACE.

CONCLUSION

SES implantation for vessels with diameter less than 2.5mm is safe and provides good long-term outcomes.

Comparison of everolimus-eluting and sirolimus-eluting coronary stents: 1-year outcomes from the Randomized Evaluation of Sirolimus-eluting Versus Everolimus-eluting stent Trial (RESET)

BACKGROUND

Several recent randomized trials comparing everolimus-eluting stent (EES) and sirolimus-eluting stent (SES) reported similar outcomes. However, only 1 trial was powered for a clinical end point, and no trial was powered for evaluating target-lesion revascularization.

METHODS AND RESULTS

Randomized Evaluation of Sirolimus-eluting versus Everolimus-eluting stent Trial is a prospective multicenter randomized open-label trial comparing EES with SES in Japan. The trial was powered for evaluating noninferiority of EES relative to SES in terms of target-lesion revascularization. From February and July 2010, 3197 patients were randomly assigned to receive either EES (1597 patients) or SES (1600 patients). At 1 year, the primary efficacy end point of target-lesion revascularization occurred in 65 patients (4.3%) in the EES group and in 76 patients (5.0%) in the SES group, demonstrating noninferiority of EES to SES (P(noninferiority)<0.0001, and P(superiority)=0.34). Cumulative incidence of definite stent thrombosis was low and similar between the 2 groups (0.32% versus 0.38%, P=0.77). An angiographic substudy enrolling 571 patients (EES, 285 patients and SES, 286 patients) demonstrated noninferiority of EES relative to SES regarding the primary angiographic end point of in-segment late loss (0.06±0.37 mm versus 0.02±0.46 mm, P(noninferiority)<0.0001, and P(superiority)=0.24) at 278±63 days after index stent implantation.

CONCLUSIONS

One-year clinical and angiographic outcome after EES implantation was noninferior to and not different from that after SES implantation in a stable coronary artery disease population with relatively less complex coronary anatomy. One-year clinical outcome after both EES and SES use was excellent with a low rate of target-lesion revascularization and a very low rate of stent thrombosis.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01035450.

Very late stent thrombosis and late target lesion revascularization after sirolimus-eluting stent implantation: five-year outcome of the j-Cypher Registry

BACKGROUND

There is a scarcity of long-term data from large-scale drug-eluting stent registries with a large enough sample to evaluate low-frequency events such as stent thrombosis (ST).

METHODS AND RESULTS

Five-year outcomes were evaluated in 12 812 consecutive patients undergoing sirolimus-eluting stent (SES) implantation in the j-Cypher registry. Cumulative incidence of definite ST was low (30 day, 0.3%; 1 year, 0.6%; and 5 years, 1.6%). However, late and very late ST continued to occur without attenuation up to 5 years after sirolimus-eluting stent implantation (0.26%/y). Cumulative incidence of target lesion revascularization within the first year was low (7.3%). However, late target lesion revascularization beyond 1 year also continued to occur without attenuation up to 5 years (2.2%/y). Independent risk factors of ST were completely different according to the timing of ST onset, suggesting the presence of different pathophysiological mechanisms of ST according to the timing of ST onset: acute coronary syndrome and target of proximal left anterior descending coronary artery for early ST; side-branch stenting, diabetes mellitus, and end-stage renal disease with or without hemodialysis for late ST; and current smoking and total stent length >28 mm for very late ST. Independent risk factors of late target lesion revascularization beyond 1 year were generally similar to those risk factors identified for early target lesion revascularization.

CONCLUSION

Late adverse events such as very late ST and late target lesion revascularization are continuous hazards, lasting at least up to 5 years after implantation of the first-generation drug-eluting stents (sirolimus-eluting stents), which should be the targets for developing improved coronary stents.

Impact of coronary calcium on outcome following sirolimus-eluting stent implantation

There remain a small but sizable number of patients who develop restenosis after sirolimus-eluting stent (SES) implantation. However, the cause of SES restenosis has not been fully elucidated. The study population consisted of 52 patients with 69 lesions who underwent noninvasive coronary imaging by 64-slice multidetector computed tomography before SES deployment. Agatston calcium scores in target lesions were measured. All patients underwent follow-up coronary angiography at 8 months. Three coronary segments (in stent, proximal edge, and distal edge) were analyzed by quantitative coronary angiography. Agatston calcium score in target lesions averaged 214.7. Late lumen losses in the proximal edge, stent, and distal edge were 0.16 ± 0.45, 0.47 ± 0.58, and 0.07 ± 0.29 mm, respectively. Lesions with restenosis at follow-up showed a trend to produce higher preprocedural calcium scores (629) compared to those without restenosis (153, p = 0.08). There was a significant positive correlation between lesion calcium score and in-stent late lumen loss (r = 0.47, p <0.01). In conclusion, assessment of coronary calcium by multidetector computed tomography might be useful to predict outcomes after SES implantation.

Clinical usefulness of the Driver(®) stent in a retrospective, collaborative, multicenter, open-label study in Japanese real-world patients with coronary artery disease and the drug-eluting stent era

The objectives of the present study were to determine predictors for target lesion revascularization (TLR) and to examine the clinical usefulness of the Driver(®) stent (a cobalt alloy, modular-type) in Japanese patients with coronary artery disease. Data on 631 Japanese patients including 241 with stable angina and 361 with acute coronary syndrome-who had been implanted with the Driver(®) stent (805 lesions) between August 2004 and February 2005-were collected retrospectively; 95.0 and 81.7% of these lesions were de novo and ACC/AHA classification B2/C type, respectively. Early angiography of 622 patients revealed 1) the preprocedural minimal lumen diameter (MLD) of 0.80 ± 0.51 mm, with lesion lengths of 17.1 ± 7.3 mm, and 2) the postprocedural MLD of 2.95 ± 0.55 mm, with MLD gains of 2.14 ± 0.68 mm. At 270 days of clinical follow-up, the incidences of major adverse cardiac events (MACE), TLR, and early stent thrombosis (ST) were 18.8, 14.7, and 0.2%, respectively; the TLR rate decreased statistically significantly to 5.3 and 5.9% when implanting the Driver(®) stent (3.5 and 4.0 mm) and by IVUS, respectively. Absence rate of diabetes mellitus, presence rate of AMI, presence rate of stent diameters of ≥3.5 mm, and presence rate of IVUS-guided PCI showed lower TLR rates, with statistically significant differences. Uni- and multivariate analyses revealed that AMI and stent diameter (≥3.5 mm) are significant predictors for TLR (0.048 and 0.047, respectively), indicating that physicians are recommended to consider these variables when selecting candidate real-world patients for IVUS-guided PCI.

Retrospective comparison of the clinical and angiographic outcomes of the sirolimus-eluting stent and the bare-metal stent in 2031 nonrandomized consecutive de novo native coronary lesions

OBJECTIVE

To evaluate the mid-term outcomes of sirolimus-eluting stents (SES; Cypher Bx Velocity) for de novo coronary stenosis in a Japanese clinical setting, and to compare these with the outcomes using bare-metal stents (BMS).

METHODS

This study was a nonrandomized, lesion-based, and single-center study, retrospectively investigated in October 2010. We enrolled 2031 consecutive cases with de novo coronary lesions treated with BMS (n=587) or SES (n=1,444) from January 2003 to May 2007. SES use ratio during the available interval was 95.5%. The primary endpoint was the incidence of target vessel failure (TVF: comprising cardiac death, nonfatal recurrent MI, definite stent thrombosis (ST), and severe restenosis [% diameter stenosis (%DS) at secondary angiography ≥70%]. The secondary endpoint was the incidence of binary in-stent restenosis (%DS >50%).

RESULTS

The TVF ratio after SES placement (6.6%) was significantly lower than that after BMS placement (11.8%, p<0.001), despite many disadvantageous variables in the SES group. SES related to the risk of TVF (mean follow-up for SES, 1,411 ± 539 days; BMS, 1,818 ± 825 days) (hazard ratio of 0.428 at 95% CI, 0.292-0.627, p<0.001). The ratio of binary in-stent restenosis after SES placement (13.4%) was significantly lower than that after BMS placement (25.1%; p<0.001). SES was significantly related to binary in-stent restenosis (odds ratio of 0.267 at 95% CI, 0.195-0.366, p<0.001).

CONCLUSION

SES has a more favorable mid-term clinical and angiographic outcome than BMS for de novo coronary stenosis in clinical settings in Japan.

Long-term safety and efficacy of low-dose clopidogrel in Japanese patients undergoing coronary stenting: a preliminary study

This study evaluated long-term safety and efficacy of low-dose (50-mg) clopidogrel in Japanese patients undergoing coronary stenting. A total of 126 patients with 153 lesions who consented to take a 50-mg maintenance dose of clopidogrel to prevent stent thrombosis were enrolled. The duration of clinical follow-up was 13.9 ± 9.7 months. There was one early stent thrombosis (0.65%). Neither late nor very late stent thrombosis was observed in patients on clopidogrel plus aspirin. Side effects of clopidogrel were observed in 9 patients (7.1%). This preliminary study shows that 50-mg maintenance dose of clopidogrel may be acceptable in Japanese patients undergoing coronary stenting.

Comparisons of baseline demographics, clinical presentation, and long-term outcome among patients with early, late, and very late stent thrombosis of sirolimus-eluting stents: Observations from the Registry of Stent Thrombosis for Review and Reevaluation (RESTART)

BACKGROUND

Stent thrombosis (ST) after sirolimus-eluting stent implantation has not yet been adequately characterized, mainly because of its low incidence.

METHODS AND RESULTS

The Registry of Stent Thrombosis for Review and Reevaluation (RESTART) is a Japanese nationwide registry of sirolimus-eluting stent-associated ST comprising 611 patients with definite ST (early [within 30 days; EST], 322 patients; late [between 31 and 365 days; LST], 105 patients; and very late [>1 year; VLST], 184 patients). Baseline demographics, clinical presentation, and long-term outcome of sirolimus-eluting stent-associated ST were compared among patients with EST, LST, and VLST. Baseline demographics were significantly different according to the timing of ST. Characteristic demographic factors for LST/VLST versus EST identified by multivariable model were hemodialysis, end-stage renal disease not on hemodialysis, absence of circumflex target, target of chronic total occlusion, prior percutaneous coronary intervention, and age <65 years. For LST versus VLST, they were hemodialysis, heart failure, insulin-dependent diabetes mellitus, and low body mass index. Patients with LST had a significantly higher rate of Thrombolysis in Myocardial Infarction grade 2/3 flow (36%) at the time of ST than those with EST (13%) (P<0.0001) and VLST (17%; P<0.0001). Mortality rate at 1 year after ST was significantly lower in patients with VLST (10.5%) compared with those with EST (22.4%; P=0.003) or LST (23.5%; P=0.009).

CONCLUSIONS

ST timing-dependent differences in baseline demographic features, Thrombolysis in Myocardial Infarction flow grade, and mortality rate suggest possible differences in the predominant pathophysiological mechanisms of ST according to timing after sirolimus-eluting stent implantation.