Firebird stent for the treatment of patients with coronary heart disease: short-term clinical outcome

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1 Journal of Geriatric Cardiology September 2009 Vol 6 No Clinical Research Firebird stent for the treatment of patients with coronary heart disease: short-term clinical outcome Hai-Ying Wang, 1 Jin-Bo Wang 1, Feng Liang 1, Da-Yi Hu 2, Ming-Ying Wu 3, Tian-Chang Li 3, Chu-Zhong Tang 2, Ji-Yun Wang 3, Chang-Lin Lu 3 1.Department of Cardiology, Daxing Hospital, Capital University of Medical Sciences, Beijing , China 2.Cardiac Center, Beijing People s Hospital, Beijing University, Beijing , China 3.Cardiac Center, Beijing Tongren Hospital, Capital University of Medical Sciences, Beijing , China Objective The sirolimus-eluting stent (SES) has dramatically reduced the rate of restenosis in comparison to that with the baremetal stent (BMS).This study aimed to evaluate the short-term efficacy and safety of Firebird stent implantation for patients with coronary heart disease (CHD). Methods From April 2006 through July 2007, 155 patients (mean age 58.93±10.27 years ) with CHD were implanted with Firebird stent or Cypher select stent at Daxing Hospital. Patients were followed up for one year. All-cause mortality, major adverse cardiac events (MACE, including cardiac death, myocardial infarction, recurrence of angina pectoris, heart failure, revascularization, and adverse arrhythmia) and stent thrombosis were compared between the 2 groups. Results Of the 155 consecutive patients, 147 patients were revascularized completely. Of these patients, 48 (with 59 lesions) were treated with Firebird stent, 59 patients (with 75 lesions) with Cypher select stent. The demographic characteristics were similar in the 2 groups. All the angiographic and procedural results were not significantly different between the 2 groups. All-cause mortality, myocardial infarction, recurrence of angina pectoris, MACE and stent thrombosis were almost identical between the 2 groups before discharge, at 6 months and at one year.conclusion The short-term efficacy and safety of Firebird stent are similar to that of the cypher select stent for the treatment of patients with CHD (J Geriatr Cardiol 2009; 6: ). Key words coronary heart disease; sirolimus-eluting stent; percutaneous coronary intervention Introduction Since the development in angioplasty,the devices and strategies of PCI have b een rap idly progressin g. Intracoronary stents not only increase procedural success rates, but also increase the safety of procedures by decreasing the need for emergency CABG surgery, and can reduce the incidence of restenosis after balloon angioplasty. 1 However, the introduction of stents is still associated with a serious complication, namely, in-stent restenosis (ISR). Regardless of which percutaneous approach is chosen to treat an in-stent restenotic lesion, including balloon angioplasty, stent, rotational atherectomy or laser angioplasty, 30% to 80% of the patients will develop restenosis within the stent, at the stent edges or both sites. Knowledge of the development of ISR, therefore, is important for effective, safe strategies for prevention and intervention. 2 The development of coronary drug-eluting stent (DES) has further revolutionized the field of interventional cardiology by reducing the incidence of restenosis after balloon Corresponding author: Dr. Liang Feng, MD, Department of Cardiology, Daxing Hospital, Capital University of Medical Science, Beijing , China; liangfeng666@yahoo.com.cn angioplasty as well as bare metal stent implantation. 3 Among DES, sirolimus-eluting stent (SES) implantation has been shown to reduce target lesion revascularization in several randomized trials with short-term as well as long-term 4-7 follow-up outcomes. However, no data are available concerning the effectiveness of Firebird stent(ses, Microport, Shanghai, China) in treatment of coronary lesions compared with cypher select stent(ses, Cordis, Johnson and Johnson Co, Miami Lake, FL, US) in real-world interventional practice. This study was to prospectively evaluate the impact of Firebird stent implantation on coronary lesions in patients with coronary artery disease, in comparison with cypher select stent. Methods Study design and patients population This was a prospective, single-center study at Daxing Hospital, which was performed between April 2006 and July One hundred and fifty-five consecutive patients(mean age 58.93±10.27 years) with coronary heart disease(chd), who underwent CAG and were implanted with Firebird stent or Cypher select stent, were enrolled. The inclusion criteria were as follows: de novo or non-stented restenotic coro-

2 158 Journal of Geriatric Cardiology September 2009 Vol 6 No 3 nary lesions; reference vessel diameter mm at target lesion; patients willing to receive clinical follow-up. Exclusion criteria were: acute myocardial infarction (AMI) within 1 week, left main or ostial coronary artery disease (diameter stenosis 50%), angiographic thrombus containing lesion, lesion unable to be pre-dilated due to severe calcification or tortuosity, bifurcation lesions needing two stents, chronic total occluded lesions, NYHA>3 or LVEF<30%, severe chronic disease and expectancy lifespan less than three years, autoimmune disease, tumour, severe liver or kidney disease and inability to comply with the follow-up requirements. PCI was performed after 7,000-10,000U heparin were injected into the artery. Lesions were treated using standard PCI techniques. All lesions were stented with an operator-selected size and length.the dual antiplatelet therapy was given after the procedure for at least one year. Follow-up endpoints Clinical evaluation was scheduled from hospital charts before discharge and telephone interviews with the patients at 6 months and one year after the initial procedure. Patients with complete revascularization(no 50% stenosis in any coronary vessels after stenting) were followed-up for allcause mortality, myocardial infarction, recurrence of angina pectoris, the major adverse cardiac events (MACE, including cardiac death, myocardial infarction, recurrence of angina pectoris, heart failure, revascularization, adverse arrhythmia) and stent thrombosis, to compare the efficacy and safety of Firebird stent with Cypher select stent. According to Academic Research Consortium (ARC) definitions of stent thrombosis, definite stent thrombosis was defined as the presence of an acute coronary syndrome with angiographic or autopsy evidence of thrombus or occlusion; probable stent thrombosis was defined as unexplained deaths within 30 days after the procedure or acute myocardial infarction involving the target-vessel territory without angiographic confirmation; possible stent thrombosis was considered in all unexplained deaths occurring at least 30 days after the procedure. 8 Statistical analysis Categorical variables were expressed as percent frequencies and continuous variables as mean±standard deviation(sd). Univariate analysis of differences between the Firebird stent and Cypher select stent groups was performed by the 2-tailed unpaired t-test for continuous outcome variables and by the chi-square or Fisher s exact tests for categorical outcome variables. A P value<0.05 was considered statistically significant. All analyses were performed with SPSS Results Baseline clinical characteristics In the 155 consecutive patients, 107 patients were revascularized c o mp l e t e l y, o f t h e s e c o mp l e t e revascularization patients, 48 patients with 59 lesions were implanted with Firebird stent, 59 patients with 75 lesions were implanted with Cypher select stent. The demographic characteristics were similar in the two groups except that more patients with acute myocardial infarction (AMI) in the Firebird stent group (52.08% vs 25.42%, P=0.005) and numerically more patients with unstable angina in the cypher select stent group (44.68% vs 61.67%, P=0.051); however, the proportion of patients with acute coronary syndrome were not significantly different between the two groups(93. 88% vs 88.14%, P=0.28). (Table 1). Table 1 Baseline characteristics Patients with Firebird Patients with Cypher P value Firebird stent (n=48) stent (n=59) Female (n, %) 16 (33.33) 16 (27.12) 0.49 Age (yrs) ± ± Previous MI (n, %) 3 (6.25) 5 (8.48) 0.73 AMI(n, %) 25 (52.08) 15 (25.42) Previous PCI (n, %) 1 (2.08) 0 (0.00) 1.00 Previous CABG (n, %) 0 (0.00) 0 (0.00) Diabetes mellitus (n, %) 9 (18.75) 12 (20.34) 0.84 Hypertension (n, %) 25 (52.08) 38 (64.41) 0.20 Total cholesterol (mmol/l) 4.80 ± ± Low density lipoprotein-c (mmol/l) 2.70 ± ± Current smoker (n, %) 27 (56.25) 33 (55.93) 0.97 Unstable angina (n, %) 21 (44.68) 37 (61.67) Acute coronary syndrome (n, %) 46 (93.88) 52 (88.14) 0.28 LVEF (% ) 56.38± ±

3 Journal of Geriatric Cardiology September 2009 Vol 6 No Clinical follow-up results The baseline lesion characteristics and procedural results were similar between the two groups (Table 2). No procedural complications occurred. Clinical follow-up was available in all patients in the two groups before discharge, and in all patients in the Firebird stent group (100.0%) and 58 patients in the Cypher select stent group (98.31%) at six months, and in 46 patients in the Firebird stent group (95.83%) and 56 patients in the Cypher select stent group (94.92%) at one year after stent implantation. Table 3 summarizes the incidences of major adverse cardiac events during the one year followup period. All-cause mortality, myocardial infarction, recurrence of angina pectoris, and the major adverse cardiac events (MACE) were almost identical in two groups before discharge and at six months and one year follow up (Table 3). Stent thrombosis According to the ARC definition, one case of probable stent thrombosis occurred in the Firebird group (2.08%), and one case of probable stent thrombosis in the Cypher select stent group (1.7%, P=1.00). And there was one case of possible stent thrombosis in each group respectively(2.08% and 1.7%, P=1.00, Table 3). No significance was found between the two groups regarding the occurrence of stent thrombosis, either definite, probable or possible stent thrombosis. Table 2 Lesion characteristics and procedure results Firebird (Lesion number=59) Cypher (Lesion number=75) P value Location of lesion (n, %) LAD 32 (54.24) 41 (54.67) 0.96 LCX 13 (20.03) 20 (26.67) 0.54 RCA 14 (23.73) 14 (18.67) 0.48 Number of target lesion per patient (n) 1.21± ± Pre-dilatation (n, %) 33 (55.93) 38 (50.67) 0.55 No. of stents per lesion (n) 1.19± ± Stent length per lesion (mm) 30.32± ± Mean stent diameterper stent (mm) * 3.01± ± Number of stent per patient (n) 1.45± ± Pressure of implantation (per stent, atm) 11.99± ± Post-dilatation (n, %) 27 (45.76) 44 (58.67) 0.14 * indicate the variables were mean value per stent Table 3 Clinical follow-up results Firebird (n=48) Cypher(n=59) P value In-hospital all-cause mortality (n, %) 0 (0) 0 (0) MI (n, %) 0 (0) 0 (0) Recurrence of angina pectoris 0 (0) 0 (0) MACE (n, %)) 0 (0) 0 (0) Six months all-cause mortality (n (%)) 1 (2.08) 0 (0) 0.45 MI (n (%) 0 (0) 1 (1.70) 1.00 Recurrence of angina pectoris 5 (10.42) 3 (5.09) 0.46 MACE (n, %) 6 (12.5) 4 (6.78) 0.34 Probable stent thrombosis (n, %) 1 (2.08) 1 (1.70) 1.00 One year all-cause mortality (n, %) 2 (4.17) 1(1.70) 0.59 MI (n, %) 0 (0) 1 (1.70) 1.00 Recurrence of angina pectoris 6 (12.5) 3 (5.09) 0.31 MACE (n, %) 8 (16.67) 5 (8.47) 0.20 Possible stent thrombosis 1 (2.08) 1 (1.70) 1.00

4 160 Journal of Geriatric Cardiology September 2009 Vol 6 No 3 Discussion Stent implantation is an effective treatment for coronary artery stenosis and is a commonly used strategy in percutaneous coronary intervention (PCI). Although stents have been proven to be effective in treating coronary dissection as well as reducing restenosis, however, bare metal stents (BMS) has a high restenosis rate. Efforts to reduce restenosis include medical coating of BMS and use of alternative materials and design, DES now appears to be a most promising approach. Now, Sirolimus-eluting stent (SES) implantation has already been confirmed to reduce the restenosis. 9 Firebird stent is sirolimus-eluting stents made in china, which has been showed a promising therapeutic option for treating patients with coronary artery disease due to its efficacy in preventing of neointimal proliferation, associated restenosis and clinical adverse events. The safety of the Firebird stent was also proved. 10,11 This study demonstrates the efficacy and safety of the Firebird stent up to one year in the treatment of symptomatic patients with de novo or non-stented coronary lesions in comparision with cypher select stent. At one year, two patients in the Firebird(4.17%) and one patient in the cypher select stent groups(1.70%)died (P=0.59). One patient in the cypher select stent group(1.70%) experienced acute myocardial infarction, and no myocardial infarction occurred in the Firebird stent group(p=1.00). No significant difference was found between the two groups in incidence of cumulative MACE in six-month and one year follow-up (Table 3). Combining the results from the present study we concluded here that the Firebird stent could provide similar clinical efficacy when compared with cypher select stent in treating patients with CHD at one years after the procedure. The safety of the Firebird stent treatment was also proved identical clinical follow-up results with cypher select stent at one year in term of stent thrombosis(table 3). Restenosis following coronary stenting has long been attributed to elastic recoil immediately following balloon deflation, neointimal proliferation triggered by injury to the vessel wall 5 and late negative remodeling. 3 Stents have been shown to completely prevent recoil and abolish remodeling to offset a stent-related increase in neointimal tissue accumulation. Any in-stent restenosis is thus composed of neointimal hyperplasia derived from smooth muscle cells and fibroblast migrating from the vessel wall. Currently, extensive data available from randomized control studies have suggested that three kinds of major factors might be contributing to ISR, namely, factors related to the lesion or the procedure, 12,13 factors that are patient-related and geneticrelated factors. 14,15 Lesion- and procedure-related factors have been demonstrated to be closely associated with ISR. Among them, the most important lesion characteristics that influence restensosis in clinical practice are the reference vessel diameter, preprocedural minimal lumen diameter, lesion length and postprocedural minimal lumen diameter. Patient-related factors that have been most consistently associated with an increased risk of stent restenosis are the presence of diabetes, the clinical setting of acute coronary syndromes and an inherent tendency to develop stent restenosis. In previous studies, however, the results in the Chinese Han population indicated that conventional coronary risk factors such as hypertension, hyperlipidemia and history of CAD were not associated with a higher rate of restenosis caused by bare metal stent (BMS) or DES implantation. 16 In the present study, the baseline, lesion characteristics and procedure results were well balanced; the incidence of recurrence of angina pectoris(rap) and MACE were not significantly difference between the two groups at six month (RAP: 10.42% vs 5.09%, P=0.46; MACE: 12.5% vs 6.78%, P=0.34) and one year follow up(rap: 12.5% vs 5.09%, P=0.31; MACE: 16.67% vs 8.47%, P=0.20). The results in this study showed that clinical outcomes of restenosis after coronary stenting were were similar between the Firebird stent group and the Cypher select stent group, it indicate the efficacy of the Firebird stent for patients with coronary heart disease were similar to the cypher select stent. Stent thrombosis in the DES era is a disturbing problem due to its catastrophic consequences for individual patient; although the incidence is rare. 17 The cause of stent thrombosis after implanting a DES is multifactorial with delayed endothelialization or healing in combination with other clinical and procedural risk factors. 18 Premature discontinuation of dual antiplatelet therapy was strongly associated with stent thrombosis. In present study, one patient(2.08%) in the Firebird stent group and one patient(1.7%)in the Cypher select stent group had probable stent thrombosis (P=1.00); and in both groups there was one case of possible stent thrombosis respectively (2.08% and 1.7%, P=1.00). It indicated that the clinical outcome rates after stent thrombosis were similar between the two groups. Several limitations of the study deserve attention. A single center study may be a limitation. Most importantly, it was not a randomized trial and there were a small number of patients in the study. Thus, the populations investigated and the interventional strategies might have been heterogeneous. The influence of selection and treatment bias cannot be ruled out. Accordingly, the results need to be confirmed by patients with randomized and multi-center trials. However, the clinical and angiographic baseline characteristics did not show relevant differences, and the same operators and interventional techniques were used. In addition, quantitative coronary angiography (QCA) measurements, intravascular ultrasound and angiographic follow-up were not performed in our study and therefore accurate quantitative analysis of restenosis lesions was not

5 Journal of Geriatric Cardiology September 2009 Vol 6 No possible. But, in term of clinical follow-up outcomes, we demonstrated that percutaneous coronary intervention in coronary lesions with Firebird stent implantations conferred to similar favorable clinical outcomes in comparision with cypher select stent in our real world clinical practice. References 1. Xu Bo, Li JJ, Yang YJ, et al. A single center investigation of baremetal or drug-eluting stent restenosis from 1633 consecutive Chinese Han population. Chin Med J 2006; 119: Li JJ, Xu B, Yang YJ, et al. Is there delayed restensosis in patients with coronary artery disease treated with sirolimus-eluting stent? Coron Artery Dis 2007; 18: Abizaid A. Sirolimus-eluting coronary stents: a review. Vasc Health Risk Manag 2007; 3: Lemos PA, Hoye A, Goedhart D,et al. Clinical, angiographic, and procedural predictors of angiographic restenosis after sirolimuseluting stent implantation in complex patients: an evaluation from the rapamycin-eluting stent evaluated at Rotterdam Cardiology Hospital (hesearch) study. Circulation 2004; 109: Nakamura M, Wada M, Hara H, et al. Angiographic and clinical outcomes of a pharmacokinetic study of sirolimus-eluting stents: Lesson from restenosis cases. Circ J 2005; 69: Nakazawa G, Tanabe K, Aoki J, et al. Clinical and angiographic outcomes of sirolimus-eluting stents implantation in Japanese patients in daily practice. Circ J 2006; 70: Ozcan T, Cin VG, Yurtdas M, et al. Angiographic and clinical outcome following sirolimus-eluting stent (cypher) implantation. Int Heart J 2007; 48: Mauri L, Hsieh WH, Massaro JM, et al. Stent thrombosis in randomized clinical trials of drug-eluting stents. N Engl J Med 2007;356: Raja SG, Dreyfus GD. Efficacy and safety of drug-eluting stents: current best available evidence. J Card Surg 2006; 21: Zhang Q, Fang YH, Zhang RY, et al. Drug-eluting stents improve post-intervention clinical outcomes in Chinese diabetic patients with de novo coronary artery disease. Chin Med J 2006; 119: Liu HB, Xu B, Gao RL, et al. Outcomes of using Firebird rapamycin eluting stents in routine coronary intervention practice: one-year results from the pilot study of Firebird in China registry. Chin Med J 2006;119: Elezi S, kastrati A, Neumann FJ, et al. Vessel size and long-term outcome after coronary stent placement. Circulation 1998; 98: Mehran R, Dangas G, Abizaid AS, et al. Angiographic patterns of in-stent restenosis: classification and implications for longterm outcome. Circulation 1999; 100: Lowe HC, Oesterle SN, Khachigian LM. Coronary in-stent restenosis: current status and future strategies. J Am Coll Cardiol 2002; 39: Sako H, Miura SI, Iwata A, et al. Changes in CCR2 chemokine receptor expression and plasma MCP-1 concentration after the implantation of bare metal stents versus sirolimus-eluting stents in patients with stable angina. Inter Med 2008; 47(1): LI JJ. Medical progress Inflammatory response, drug-eluting stent and restenosis. Chin Med J 2008;121(6): Iakovou I, Schmidt T, Bonizzoni E, et al. Incidence, predictors, and outcome of thrombosis after successful implantation of drug-eluting stents. JAMA 2005; 293: Joner M, Finn AV, Farb A, et al. Pathology of drug-eluting stents in humans: delayed healing and late thrombotic risk. J Am Coll Cardiol 2006; 48: