Xiongshao for restenosis after percutaneous coronary intervention in patients with coronary heart disease

Background Percutaneous coronary intervention (PCI) with stent placement is a standard treatment for coronary heart disease (CHD). In-stent restenosis after PCI remains an important clinical problem. Xiongshao capsule has been reported to be beneficial in preventing restenosis after PCI in CHD patients. However, the strength of evidence to support its use is unclear. Objectives To systematically assess the efficacy and safety of Chinese herbal medicine Xiongshao capsule in preventing restenosis after PCI in patients with CHD. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 3 of 2012), MEDLINE (OVID) (1948 to week 1 March 2012), EMBASE (OVID) (1980 to week 10 2012), ISI Web of Science with Conference Proceedings (1970 to 14 March 2012), LILACS (1982 to 15 March 2012), Chinese biomedical literature database (1980 to May 2012), China National Knowledge Infrastructure (1994 to May 2012), Chinese Medical Current Contents (1994 to May 2012), VIP Database for Chinese Technical Periodicals (1989 to May 2012), Chinese Master's Theses Full-Text Database (1994 to May 2012), China Doctor Dissertation Full-Text Database (1994 to May 2012), and China Proceedings of Conference Full-Text Database (1994 to May 2012). We also searched ongoing trials and research registries. Selection criteria All randomised controlled trials comparing Xiongshao capsule alone/plus conventional western medicine with the same conventional western medicine alone/plus placebo in participants with CHD who met the recognised diagnostic criteria and had successfully undergone a PCI procedure were included. Data collection and analysis Two review authors independently selected trials and extracted data. Two review authors independently assessed the risk of bias of included trials using The Cochrane Collaboration tool, and any disagreements were resolved by discussion with a third review author. Data were pooled for meta-analysis using the fixed-effect model, and the results were expressed as risk ratios (RRs) with 95% confidence intervals (CIs). Main results Four trials involving 649 participants were included in this review. Two of these trials (459 participants) were designed as randomised, double-blind, placebo-controlled trials with an adequate methodological description; the other two trials (190 participants) described an inadequate methodological design. All four trials with 649 participants were included in the meta-analysis. Significant differences were noted in rates of restenosis, recurrence angina pectoris, and serious cardiovascular adverse events between Xiongshao capsule plus conventional western medicine and the same conventional western medicine alone; RR values (95% CIs) were 0.41 (0.22 to 0.75), 0.47 (0.31 to 0.72), and 0.47 (0.25 to 0.90), respectively. Xiongshao capsule plus conventional western medicine showed more significant reductions in restenosis (RR 0.52, 95% CI 0.33 to 0.80), recurrence angina pectoris (RR 0.26, 95% CI 0.18 to 0.38), and serious cardiovascular adverse events (RR 0.45, 95% CI 0.28 to 0.70) than the same conventional western medicine plus placebo. Safety outcomes and adverse events of the Xiongshao capsule were reported in two trials, which reported no adverse events. Authors' conclusions The summary estimates indicate a protective effect of Xiongshao on restenosis and suggest that Xiongshao capsule may be used to prevent restenosis after a PCI procedure in CHD patients. However, this evidence is derived from small randomised trials, all conducted in China, and two of the included trials showed important methodological limitations that undermine the validity of the findings. Additional high-quality research trials with sufficient sample size are required.