Journal of the American College of Cardiology
A Randomized Comparison of Sirolimus- Versus Paclitaxel-Eluting Stent Implantation in Patients With Diabetes Mellitus
Author + information
- Received December 3, 2007
- Revision received April 14, 2008
- Accepted April 15, 2008
- Published online August 26, 2008.
Author Information
- Seung-Whan Lee, MD, PhD⁎,
- Seong-Wook Park, MD, PhD, FACC⁎,⁎ (swpark{at}amc.seoul.kr),
- Young-Hak Kim, MD, PhD⁎,
- Sung-Cheol Yun, PhD⁎,
- Duk-Woo Park, MD, PhD⁎,
- Cheol Whan Lee, MD, PhD⁎,
- Myeong-Ki Hong, MD, PhD⁎,
- Kyoung-Suk Rhee, MD, PhD†,
- Jei Keon Chae, MD, PhD†,
- Jae-Ki Ko, MD, PhD†,
- Jae-Hyeong Park, MD, PhD‡,
- Jae-Hwan Lee, MD, PhD‡,
- Si Wan Choi, MD‡,
- Jin-Ok Jeong, MD, PhD‡,
- In-Whan Seong, MD, PhD‡,
- Yoon Haeng Cho, MD, PhD§,
- Nae-Hee Lee, MD, PhD§,
- June Hong Kim, MD, PhD∥,
- Kook-Jin Chun, MD∥,
- Hyun-Sook Kim, MD, PhD¶ and
- Seung-Jung Park, MD, PhD, FACC⁎
- ↵⁎Reprint requests and correspondence:
Dr. Seong-Wook Park, Department of Medicine, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Poongnap-dong, Songpa-gu, Seoul, 138-736, Korea.
Abstract
Objectives The aim of this study was to compare the effectiveness of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) in patients with diabetes mellitus (DM).
Background Drug-eluting stent implantation significantly improved the angiographic and clinical outcomes compared with bare-metal stent implantation in diabetic patients. However, comparison of SES with PES in diabetic patients has not been sufficiently evaluated.
Methods This prospective, multicenter, randomized study compared SES (n = 200) and PES implantation (n = 200) for diabetic patients (n = 400). The primary end point was in-segment restenosis at 6 months according to intention-to-treat principle.
Results The 2 groups had similar baseline clinical and angiographic characteristics. Six-month in-stent (3.4% vs. 18.2%, p < 0.001) and in-segment restenosis (4.0% vs. 20.8%, p < 0.001) and 9-month target lesion revascularization (2.0% vs. 7.5%, p = 0.017) were significantly lower in the SES versus the PES group. The incidence of death (0% in SES vs. 0.5% in PES, p = 0.999) or myocardial infarction (0.5% in SES vs. 0.5% in PES, p =0.999) at 9-month follow-up was not statistically different between the 2 groups. Major adverse cardiac events including death, myocardial infarction, and target lesion revascularization at 9 months (2.0% vs. 8.0%, p = 0.010) were lower in the SES versus the PES group.
Conclusions Sirolimus-eluting stent implantation is superior in reducing angiographic restenosis and improving 9-month clinical outcomes in patients with DM and coronary artery disease compared with PES implantation.
Diabetic patients often present unfavorable coronary anatomy with small and diffusely diseased vessels (1) and exhibit exaggerated neointimal hyperplasia after bare-metal stent (BMS) implantation compared with nondiabetic subjects (2). Although drug-eluting stent (DES) implantation significantly reduced the neointimal hyperplasia and angiographic restenosis compared with BMS in diabetic patients (3), presence of diabetes mellitus (DM) has been still associated with an increased risk of restenosis and unfavorable clinical outcomes in the era of DES (4,5). Recently, the relative efficacies of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) in patients with DM have been evaluated in randomized and registry studies (6–10). Although some studies found SES to have greater efficacy than PES in diabetic patients (9,10), controversy remains (6–8). Therefore, to compare the effectiveness of 2 DES (SES and PES) in patients with DM, we performed a randomized, multicenter, prospective study comparing SES and PES in diabetic patients (DES-DIABETES [Drug-Eluting Stent in patients with DIABETES mellitus] trial).
Methods
Patient selection
This prospective randomized study included 400 patients ≥18 years of age with angina pectoris and/or a positive stress test and a native coronary lesion. The study involved 5 cardiac centers in Korea between May 2005 and March 2006. Patients were considered eligible if they had DM, presented with angina pectoris, or had a positive stress test and had clinically significant angiographic stenosis in a native coronary vessel with a diameter stenosis ≥50% and visual reference diameter ≥2.5 mm. Patients were excluded if they had a contraindication to aspirin, clopidogrel, or cilostazol; left main disease (diameter stenosis ≥50% by visual estimate); graft vessel disease; left ventricular ejection fraction <30%; recent history of hematologic disease or leukocyte count <3,000/mm3and/or platelet count <100,000/mm3; hepatic dysfunction with asparatate aminotransferase (AST) or alanine aminotransferase (ALT) ≥3 times the upper normal reference limit; history of renal dysfunction or serum creatinine level ≥2.0 mg/dl; serious noncardiac comorbid disease with a life expectancy <1 year; planned bifurcation stenting in the side branch; primary angioplasty for acute myocardial infarction (AMI) within 24 h; or inability to follow the protocol. In patients with multiple lesions fulfilling the inclusion and exclusion criteria, the first stented lesion was considered as target lesion. The institutional review board at each participating center approved the protocol. All patients provided written informed consent.
Randomization and procedures
Once the guidewire had crossed the target lesion, patients were randomly assigned in a 1:1 ratio to SES or PES implantation. After DES randomization, patients were randomly allocated in a 1:1 ratio to the triple antiplatelet group (aspirin, clopidogrel, and cilostazol; triple group; n = 200) or the dual antiplatelet therapy group (aspirin and clopidogrel; standard group; n = 200) (antiplatelet arm) on the basis of a 2 × 2 factorial design with a computer-generated randomization sequence. Random assignments were stratified according to participation sites and blocked with block size of 4 or 6 and were distributed in sealed envelopes to each participating center. The block size was concealed. From at least 24 h before the procedure and thereafter, all patients received aspirin (200 mg daily) and clopidogrel (loading dose of 300 mg, followed by 75 mg daily for at least 6 months). Patients in the triple group received a loading dose of 200 mg cilostazol immediately after the procedure and 100 mg twice/day for 6 months.
Coronary stenting was performed with the standard technique. The decision of pre-dilation or direct stenting was made by the operator. The use of intravenous glycoprotein IIb/IIIa inhibitors was at the operator's discretion. A 12-lead electrocardiogram was obtained after the procedure and before discharge. Serum levels of creatine kinase-myocardial band isoenzyme were assessed 8, 12, and 24 h after the procedure and thereafter if considered necessary.
Study end point and definitions
The primary end point of this trial was in-segment restenosis on 6-month follow-up study (defined as in-segment stenosis of at least 50%). The secondary end points included 6-month angiographic outcomes such as in-segment late loss and the rate of in-stent restenosis at 6 months (defined as in-stent stenosis of at least 50%), stent thrombosis, target vessel revascularization (TVR), and major adverse cardiac events (MACE) including death, myocardial infarction (MI), and target lesion revascularization (TLR).
The diagnosis of DM was considered confirmed in all patients receiving active treatment with an oral hypoglycemic agent or insulin; for patients with a diagnosis of diabetes who were on a dietary therapy alone, enrollment in the trial required the documentation of an abnormal blood glucose level after an overnight fast. Angiographic success was defined as in-segment final diameter stenosis <30% by quantitative coronary angiography (QCA). A Q-wave MI was defined by the post-procedural presence of new Q waves of >0.04 s in 2 contiguous leads. Non–Q-wave MI was defined as a creatine kinase-myocardial band fraction >3 times the upper limit of normal. Target lesion revascularization was considered clinically driven if prompted by symptoms consistent with myocardial ischemia, if preceded by an abnormal stress test result consistent with myocardial ischemia, if there were other electrocardiographic changes consistent with myocardial ischemia, or if the lesion diameter stenosis was more than 70% at follow-up (11). Stent thrombosis was defined as any of the following after the procedure: angiographic documentation of stent occlusion with or without the presence of thrombus associated with an acute ischemic event, unexplained sudden death, or MI not clearly attributable to another coronary lesion (12,13).
Follow-up
Repeat coronary angiography was mandatory at 6 months after stenting or earlier if indicated by clinical symptoms or evidence of myocardial ischemia. Clinical follow-up visits were scheduled at 30, 90, 180, and 270 days. At every visit, physical examination, electrocardiogram, cardiac events, and angina recurrence were monitored. At each participating center, patient data were recorded prospectively on standard case report forms and gathered in the central data management center (Asan Medical Center, Seoul, Korea). All adverse clinical events were adjudicated by an independent events committee blinded to the treatment groups.
QCA analysis
Coronary angiograms were obtained after intracoronary nitroglycerin administration. Procedure (baseline), post-procedure, and follow-up angiograms were submitted to the angiographic core analysis center (Asan Medical Center, Seoul, Korea), in which intraobserver and interobserver correlation coefficients were 0.92 and 0.93, respectively. Digital angiograms were analyzed with an automated edge detection system (CASS II, Pie Medical, Maastricht, the Netherlands). The core laboratory was blinded to the treatment assignment. Angiographic variables included absolute lesion length, stent length, reference vessel diameter, minimal lumen diameter (MLD), percent diameter stenosis, binary restenosis rate, acute gain, late loss, and the patterns of recurrent restenosis. The QCA measurements of target lesions were obtained for both the stented segment only (in-stent) and the region including the stented segment as well as the margins 5 mm proximal and distal to the stent (in-segment). In-segment late loss was calculated with maximal regional late loss method (14). Patterns of angiographic restenosis were quantitatively assessed with the Mehran classification (15).
Statistical analysis
On the basis of results from a previous study (10), we assumed an in-segment angiographic restenosis rate of 7% in the SES group and 19% in the PES group. With a 2-sided 5% significance level, we estimated that 163 patients/group were needed to detect this difference with a statistical power of 90%. Expecting that approximately 20% of the patients would not return for angiographic follow-up, total sample size was estimated to 400 patients (200 patients/group). Analyses of 2 groups were performed according to the intention-to-treat principle. Continuous variables are presented as mean ± SD or median (interquartile range [IQR]) and compared with Student unpaired tor Mann-Whitney Utests. Categorical variables are presented as numbers or percentages and were compared with chi-square or Fisher exact tests. The relative risk (RR) and its 95% confidence interval (CI) were computed for outcome measures. The Breslow-Day test was performed to assess the homogeneity of the RR across participating centers and use of cilostazol (16). The adjusted RR and CI after controlling the center and use of cilostazol were computed by the Mantel-Haenszel method. For the primary outcome, we also calculated the absolute difference between SES and PES patients with and without cilostazol. A p value <0.05 was considered to indicate a significant difference. All statistical analyses were performed with SAS version 9.1 (SAS Institute, Cary, North Carolina).
Results
Baseline characteristics of the patients
Table 1shows the baseline clinical characteristics of the study groups. There were no significant differences between the 2 groups in baseline clinical characteristics and risk factors.
Baseline Clinical Characteristics
Procedural results and in-hospital outcomes
Table 2shows angiographic characteristics and procedural results. The 2 groups have similar anatomical and procedural characteristics. All stents were successfully implanted, and the angiographic success rate was 99.5% in all groups. The 2 groups were treated with similar stented lengths and number of implanted stents/target lesion. Procedure-related non–Q-wave MI occurred similarly in both arms. Acute stent thrombosis developed in 1 patient (0.5%) treated with SES during hospital stay. In-hospital events, including Q-wave MI, emergency bypass surgery, or death, did not occur in either group.
Angiographic Characteristics and Procedural Results
Angiographic outcomes
Baseline and post-procedural QCA outcomes for study groups are shown in Table 3.The 2 groups had similar baseline and post-procedural QCA characteristics, except for higher maximal inflation pressure in the SES group versus the PES group.
Quantitative Angiographic Measurements
Follow-up angiography was performed in 330 patients (82.5%)—176 (88%) SES and 154 (77%) PES patients. The median duration of angiographic follow-up was similar in the 2 groups (187 [IQR: 178 to 201] and 188 [IQR: 178 to 203] days for the SES and PES groups, respectively, p = 0.762). Results of QCA measurements at follow-up are shown in Table 3. The in-stent and -segment late loss were significantly lower in the SES versus in the PES group. Follow-up in-stent and -segment MLD also were significantly larger in SES versus in PES. In-segment restenosis, the pre-specified primary end point, was identified in 7 (4.0%) SES and 32 (20.8%) PES patients (RR: 0.19; 95% CI: 0.09 to 0.42; p < 0.001). In-stent restenosis rate was also lower in the SES than in the PES group (3.4% vs. 18.2%; RR: 0.19; 95% CI: 0.08 to 0.44; p < 0.001). The test for assessing the homogeneity of the RR across the center and use of cilostazol were not significant for in-segment (Breslow-Day test, p = 0.317) and in-stent restenosis (Breslow-Day test, p = 0.246). Although there was interaction between types of DES and use of cilostazol in relative measure (p < 0.001 for in-segment restenosis), absolute measure was not statistically significant (p = 0.861). This phenomenon was due to 0% in-segment restenosis of the SES + cilostazol group. With regard to in-segment restenosis, the pre-specified primary end point, absolute difference was 8% in SES patients and 6.8% in PES patients, according to use of the cilostazol (p = 0.861) (Fig. 1).
The In-Segment Restenosis Rate According to Drug-Eluting Stent and Use of Cilostazol
There is interaction between the type of drug-eluting stent and use of cilostazol for in-segment restenosis (p < 0.001). Although there was significant difference in relative measure of in-segment restenosis rate due to 0% in-segment restenosis rate of the sirolimus-eluting stent + cilostazol group, the absolute measure was not statistically different (p = 0.861).
In patients with restenoses, a pattern of focal restenosis (type I) was more common in the SES than in the PES group (Table 4).
Angiographic Patterns of Restenosis
Clinical outcomes
A minimum 9-month clinical follow-up was performed in all patients. One cardiac death occurred in PES patients due to nontarget vessel MI. Myocardial infarction occurred in 1 patient/group. During 9 months, only 1 stent thrombosis occurred in the SES patients, which was angiographically documented at 6 h after index procedure. The patient was successfully treated with repeat intervention (Table 5).
Clinical Outcomes at 9 Months
The rates of TLR (2.0% vs. 7.5%; RR: 0.27; 95% CI: 0.09 to 0.79; p = 0.017) and TVR (3.5% vs. 8.0%, p = 0.053) were lower in the SES than in the PES group. Clinically driven TLR (1.5% vs. 6.0%, p = 0.032) and TVR (2.0% vs. 7.5%, p = 0.017) rates were also lower in the SES than in the PES group. At 9 months, MACE was lower in the SES than in the PES group (2.0% vs. 8.0%; RR: 0.25; 95% CI: 0.09 to 0.73; p = 0.010). The composite of death, MI, or TVR was also significantly lower in the SES than in the PES patients (3.5% vs. 8.5%, p = 0.035).
Discussion
The major finding of this study is that SES implantation is associated with reduction of late loss and 6-month angiographic restenosis, relative to PES implantation, which is translated to reduction of subsequent TLR and MACE with no difference of death or MI in patients with DM.
Drug-eluting stents significantly reduced angiographic restenosis and cardiac events compared with BMS in patients with DM (3). The presence of DM is associated with higher neointimal hyperplasia, restenosis, and unfavorable clinical outcomes in the era of DES (17,18). Recently, several randomized trials and registries showed inconsistent results regarding the superiority of SES over PES in diabetic patients (6–10). The current study shows that SES are more effective than PES in reducing angiographic restenosis and subsequent clinical outcomes.
In the current study, the in-stent (0.13 ± 0.43 mm vs. 0.53 ± 0.57 mm, p < 0.001) and in-segment late loss (0.31 ± 0.40 mm vs. 0.67 ± 0.53 mm, p < 0.001) were significantly lower in the SES than in the PES group. Although in previous studies, the late loss of the SES group (in-stent: 0.09 ± 0.4 mm to 0.26 ± 0.40 mm; in-segment: 0.41 ± 0.6 mm to 0.43 ± 0.45 mm) and the PES group (in-stent: 0.46 ± 0.64 mm to 0.50 ± 0.6 mm; in-segment: 0.67 ± 0.62 mm to 0.68 ± 0.6 mm) had somewhat different results than our study due to study design, enrolled patient/lesion characteristics, and stenting procedures (3,9,19,20), the 2 randomized studies comparing SES and PES in diabetic patients showed that the SES group had significantly reduced late loss compared with the PES group (9,20), which was a finding consistent with that of our study.
We also found that SES reduced in-segment restenosis (4.0% vs. 20.8%, p < 0.001), the pre-specified primary end point, by 81% (relative reduction) compared with PES. Previous registry data comparing SES and PES also showed a restenosis rate similar to those of our study (5.3% in SES and 23.1% in PES, p < 0.01) (10). However, this relative reduction is greater than those reported in previous randomized studies of various lesion subsets that showed a 7% to 77.2% relative reduction (9,21–23). The current study involved diabetic patients with a relatively long diseased segment, which might have contributed to the more pronounced differences between the 2 stents. According to previous randomized trials comparing SES versus PES, SES showed a more profound benefit over PES in more complex patients/lesions (9,22,23)—such as diabetic patients, in-stent restenosis, and long lesions—than in trials involving relatively simple lesions (11,24). The restenosis rate of ISAR-DIABETES (The Intracoronary Stenting and Angiographic Results: Do Diabetic Patients Derive Similar Benefit from Paclitaxel-Eluting and Sirolimus-Eluting Stents) (9), a randomized study comparing SES and PES in diabetic patients, was 6.9% in SES and 16.5% in PES patients. Our study had longer lesion length (25.8 mm of SES and 27.2 mm of PES) than those of ISAR-DIABETES (12.4 mm of SES and 13.4 mm of PES), which would partly explain the profound superiority of SES over PES in our study.
Due to the reduced risk of angiographic restenosis, the subsequent TLR (2.0% vs. 7.5%; RR: 0.27; 95% CI: 0.09 to 0.79; p = 0.017) was significantly reduced in SES patients compared with PES patients. These results were also found in a recent meta-analysis comparing SES and PES in a variety of clinical settings and lesion complexity, in which SES significantly reduced the risk of reintervention (25). In our study, death or MI was similar in the 2 groups. Consequently, MACE including death, MI, and TLR was significantly lower in SES than in PES patients, mainly driven by TLR (2.0% vs. 8.0%, p = 0.010).
Diabetes mellitus has been reported to be associated with antiplatelet resistances (26). This is explained by aggressive atherosclerosis, abnormal endothelial function, impaired fibrinolysis, and platelet hyperactivity after arterial injury. Importantly, increased platelet activity is considered critically involved in the increased thrombogenic potential among diabetic patients. These findings might be associated with an increased risk of stent thrombosis after coronary stenting, which has been reported in previous registry data of DES (27). Furthermore, a recent meta-analysis showed that the PES had an increased risk of stent thrombosis compared with SES during a mean follow-up period ranging from 9 to 37 months (25). However, in our study, stent thrombosis occurred in only 1 patient receiving SES during 9 months. Thus, to evaluate the impact of DM on stent thrombosis after DES implantation, a larger population study would be required.
Study limitations
The present study has several limitations. First, our use of routine 6-month angiography might have resulted in an underestimation of the rates of restenosis and TLR compared with a study with a longer angiographic follow-up period. Second, there might be possible bias associated with clinical decisions related to TLR by operators, but this limitation has mostly been compensated for by ischemic-driven TLR. Third, the rate of angiographic follow-up was nonuniform in both groups.
Conclusions
The present study showed that SES implantation resulted in a significantly reduced risk of 6-month angiographic restenosis and 9-month TLR or MACE without a significant difference in MI or death compared with PES implantation.
Footnotes
This study was supported by the Cardiovascular Research Foundation (Korea), a grant from the Korean Ministry of Health & Welfare as part of the Korea Health 21 Research & Development Project (0412-CR02-0704-0001).
- Abbreviations and Acronyms
- AMI
- acute myocardial infarction
- BMS
- bare-metal stent(s)
- CI
- confidence interval
- DES
- drug-eluting stent(s)
- DM
- diabetes mellitus
- IQR
- interquartile range
- MACE
- major adverse cardiac events
- MI
- myocardial infarction
- MLD
- minimal lumen diameter
- PES
- paclitaxel-eluting stent(s)
- QCA
- quantitative coronary angiography
- RR
- relative risk
- SES
- sirolimus-eluting stent(s)
- TLR
- target lesion revascularization
- TVR
- target vessel revascularization
- Received December 3, 2007.
- Revision received April 14, 2008.
- Accepted April 15, 2008.
- American College of Cardiology Foundation
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