Treatment effects of systematic two-stent and provisional stenting techniques in patients with complex coronary bifurcation lesions: rationale and design of a prospective, randomised and multicentre DEFINITION II trial.

INTRODUCTION: Provisional stenting (PS) for simple coronary bifurcation lesions is the mainstay of treatment. A systematic two-stent approach is widely used for complex bifurcation lesions (CBLs). However, a randomised comparison of PS and two-stent techniques for CBLs has never been studied. Accordingly, the present study is designed to elucidate the benefits of two-stent treatment over PS in patients with CBLs. METHODS AND ANALYSIS: This DEFINITION II study is a prospective, multinational, randomised, endpoint-driven trial to compare the benefits of the two-stent technique with PS for CBLs. A total of 660 patients with CBLs will be randomised in a 1:1 fashion to receive either PS or the two-stent technique. The primary endpoint is the rate of 12-month target lesion failure defined as the composite of cardiac death, target vessel myocardial infarction (MI) and clinically driven target lesion revascularisation. The major secondary endpoints include all causes of death, MI, target vessel revascularisation, in-stent restenosis, stroke and each individual component of the primary endpoints. The safety endpoint is the occurrence of definite or probable stent thrombosis. ETHICS AND DISSEMINATION: The study protocol and informed consent have been approved by the Institutional Review Board of Nanjing First Hospital, and accepted by each participating centre. Written informed consent was obtained from all enrolled patients. Findings of the study will be published in a peer-reviewed journal and disseminated at conferences. TRIAL REGISTRATION NUMBER: NCT02284750; Pre-results.

Angiographic prevalence of myocardial bridging in a defined very large number of Chinese patients with chest pain.

BACKGROUND: Muscle fibers overlying the intramyocardial segment of an epicardial coronary artery are termed myocardial bridging (MB). Variable prevalence of MB has been described at autopsy and angiographic series with small and large sample size studies. In addition, no similar study was reported in Chinese population. The aim of this study was to investigate the angiographic prevalence of MB in consecutive 37,106 Chinese patients with chest pain from our center. METHODS: We conducted an observational study to evaluate the consecutive cases with MB among patients undergone selective coronary angiography, and analyzed the angiograhic prevalence and clinical features of MB in this study of very large sample size. RESULTS: Among 37 105 patients with chest pain we found 1002 cases with 1011 MBs in a retrospective manner, and the overall prevalence was 2.70%. Although more than 99% (991/1002) of patients had single bridge, 8 cases were found to have more than two MBs (seven with two, and one with three). Altogether 54.39% of cases (545/1002) had MB without atherosclerotic lesions, and 96.24% (973/1011) of bridging located in the left anterior descending coronary artery (LAD), mainly in the middle of LAD (792/1011, 78.33%). According to Nobel classification, of the single bridge (n=991), <50% of obstruction was predominant (471/991, 47.52%). Totally 50%-69% accounted for 34.81% (345/991), >70% of obstruction was 17.65% (175/991). CONCLUSIONS: These data showed that the prevalence of angiographically detectable MB in Chinese patients with chest pain was similar to those of the previous studies, with 2.7% prevalence in this very large sample size.

[Electrophysiological characterization of long QT syndrome associated mutations V630A and N633S].

OBJECTIVE: To identify the electrophysiological properties of long-QT syndrome (LQTS) associated missense mutations in the outer mouth of the HERG potassium channel in vitro. METHODS: Mutations V630A and N633S were constructed by Megaprimer PCR method and cRNA were produced by T7 RNA polymerase. The electrophysiological properties of the mutation were investigated in the Xenopus oocyte heterologous expression system. RESULTS: Coexpression of mutant and wild-type HERG subunits caused a dominant-negative effect, and the currents were significantly decreased. Compared with wild-type HERG channels, V630A and N633S mutations were related to decreased time constants for inactivation for V630A/WT and N633S/WT at all potentials, reduced slope conductance and the voltage dependence of steady-state inactivation was shifted to negative potentials for V630A/WT and N633S/WT. CONCLUSION: Present study shows that LQTS associated missense mutations located in the outer mouth of HERG cause a dominant-negative effect and alterations in steady-state voltage dependence of channel gating of heteromultimeric channels suggesting a reduction in expressional current might be one of the pathophysiologic mechanisms of LQTS.