Shinichiro Uchikawa

Coronary microvascular response to intracoronary administration of nicorandil

Nicorandil is an antianginal drug that causes potent coronary vasodilation of both epicardial and resistance vessels. To measure the dose-response kinetics of bolus injections of intracoronary nicorandil and to compare the vasodilatory response to nicorandil with that of intracoronary papaverine in humans, coronary blood flow velocity was measured in 30 patients using a 3Fr intravascular Doppler catheter. Continuous intravenous nitroglycerin 6 to 8 micrograms/min was infused to achieve maximal vasodilation of the epicardial vessels. Bolus doses of nicorandil dissolved in warmed saline solution were injected into the left (0.1, 0.2, 0.5, 1.0, 1.5, and 2.0 mg) and right (0.1, 0.2, 0.4, 0.8, 1.0, and 1.5 mg) coronary arteries. Intracoronary nicorandil caused a dose-dependent increase in coronary flow velocity and a decrease in coronary vascular resistance. Maximal vasodilatory effects equivalent to those obtained with 12 +/- 2 mg of intracoronary papaverine were induced with nicorandil 1.5 mg in the left coronary artery, and effects similar to those of 10 +/- 2 mg of papaverine were produced with nicorandil 1.0 mg in the right coronary artery. The time from injection of nicorandil to the onset of maximal hyperemia and duration of hyperemia were significantly shorter after nicorandil than after papaverine in both coronary arteries. Each dose of nicorandil produced no clinical symptoms and fewer changes in systemic hemodynamics and electrocardiographic QT intervals than did papaverine. These results suggest that a bolus administration of intracoronary nicorandil can safely, quickly, and reliably induce maximal coronary hyperemia comparable to that achieved with intracoronary papaverine in humans.

Impact of mitral regurgitation on long-term survival in patients with ischemic cardiomyopathy: efficacy of combined mitral valve repair and revascularization.

Ischemic cardiomyopathy complicated by severe mitral regurgitation (MR) has a poor prognosis. In such cases, whether mitral valve repair for MR improves the prognosis of survival remains unclear. In this study, 50 patients diagnosed with ischemic cardiomyopathy at our hospital between August 1991 and August 1996 were studied to examine the long-term prognosis and factors determining the prognosis. Among 17 patients with the complication of severe MR, 11 underwent mitral valve repair (repair group) and 6 did not (nonrepair group). Among the 33 patients without MR, 15 underwent revascularization (revascularization group) and 18 received medical treatment alone (medical group). Patients with MR showed significantly poorer baseline activities of daily living (ADL) [New York Heart Association (NYHA) class III or above: MR(+) vs MR(−) = 14 vs 8; P = 0.0001] and survival rate [MR(+) vs MR(−); log rank = 3.8, P = 0.05]. In contrast, patients in whom mitral valve repair was actively performed to resolve MR had favorable outcomes for both ADL (NYHA class improved from 3.9 ± 0.3 to 2.7 ± 1.0; P = 0.0004) and survival rate (MV repair vs nonrepair: long rank = 10.1, P = 0.0015). In addition, among patients without MR, the revascularization group showed more favorable results in terms of ADL (NYHA class improved from 3.5 ± 0.7 to 2.5 ± 0.8; P = 0.0059) and survival rate (revascularization vs medical: log rank = 3.7, P = 0.05), irrespective of improvement of left ventricular function. When the factors determining the prognosis for ischemic cardiomyopathy were examined by multivariate analysis, whether or not revascularization was conducted, the presence or absence of mitral regurgitation, and if present, whether or not mitral valve repair was performed were identified as independent factors determining the prognosis (revascularization: hazard ratio = 0.121, P = 0.012; absence of MR: hazard ratio = 0.104, P = 0.050; mitral valve repair: hazard ratio = 0.018, P = 0.005). These results showed that revascularization should be conducted as actively as possible in patients with ischemic cardiomyopathy; in addition, for those patients with mitral regurgitation, mitral valve repair should be conducted actively to relieve it.

Predictive Value of Combining the Ankle-Brachial Index and SYNTAX Score for the Prediction of Outcome After Percutaneous Coronary Intervention (from the SHINANO Registry)

The Synergy Between PCI With TAXUS and Cardiac Surgery (SYNTAX) score is effective in predicting clinical outcome after percutaneous coronary intervention (PCI). However, its prediction ability is low because it reflects only the coronary characterization. We assessed the predictive value of combining the ankle-brachial index (ABI) and SYNTAX score to predict clinical outcomes after PCI. The ABI-SYNTAX score was calculated for 1,197 patients recruited from the Shinshu Prospective Multi-center Analysis for Elderly Patients with Coronary Artery Disease Undergoing Percutaneous Coronary Intervention (SHINANO) registry, a prospective, observational, multicenter cohort study in Japan. The primary end points were major adverse cardiovascular and cerebrovascular events (MACE; all-cause death, myocardial infarction, and stroke) in the first year after PCI. The ABI-SYNTAX score was calculated by categorizing and summing up the ABI and SYNTAX scores. ABI ≤ 0.49 was defined as 4, 0.5 to 0.69 as 3, 0.7 to 0.89 as 2, 0.9 to 1.09 as 1, and 1.1 to 1.5 as 0; an SYNTAX score ≤ 22 was defined as 0, 23 to 32 as 1, and ≥ 33 as 2. Patients were divided into low (0), moderate (1 to 2), and high (3 to 6) groups. The MACE rate was significantly higher in the high ABI-SYNTAX score group than in the lower 2 groups (low: 4.6% vs moderate: 7.0% vs high: 13.9%, p = 0.002). Multivariate regression analysis found that ABI-SYNTAX score independently predicted MACE (hazards ratio 1.25, 95% confidence interval 1.02 to 1.52, p = 0.029). The respective C-statistic for the ABI-SYNTAX and SYNTAX score for 1-year MACE was 0.60 and 0.55, respectively. In conclusion, combining the ABI and SYNTAX scores improved the prediction of 1-year adverse ischemic events compared with the SYNTAX score alone.

Two Cases of Bronchial Asthma After Treatment with Amiodarone

IMAMURA H., et al.: Two Cases of Bronchial Asthma After Treatment with Amiodarone. Amiodarone is a highly effective antiarrhythmic agent for the prevention of life‐threatening arrhythmias. Two cases are described of patients who developed bronchial asthma after treatment with amiodarone. The bronchial asthma resolved after the dose of amiodarone was decreased in both patients. To our knowledge, an association between amiodarone and severe bronchial asthma has previously been reported only once in the medical literature. Physicians should note that amiodarone may cause bronchospasm in susceptible patients.