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Background: Insulin resistance associated with compensatory hyperinsulinemia plays a significant role in the pathogenesis of cardiovascular diseases, including vasospastic angina (VSA). However, the effects of insulin resistance associated with hyperinsulinemia on the long-term prognosis in patients with VSA remain unclear., Methods: A total of 265 selected patients with VSA and 56 control subjects with atypical chest pain were enrolled in the present study. Patients with VSA had a positive acetylcholine (ACh) provocation test with normal coronary angiograms, and control subjects had a negative ACh test and normal coronary angiograms. A 75-g oral glucose tolerance test was performed, and the plasma glucose and immunoreactive insulin (IRI) levels were measured before, and 30 min and 120 min (IRI 120) after the 75-g glucose load., Results: During the median follow-up period of 90.0 months, thirty-one patients developed cardiac events, including 6 sudden cardiac deaths and 25 readmissions for acute coronary syndrome. Cardiac events occurred in 38.9% of the patients with an IRI 120 ≥ 80 μU/ml and only 1.6% of the patients with an IRI 120<80 μU/ml (log rank 77.220, p<0.001). A multivariate analysis showed that an IRI 120 ≥ 80 μU/ml (hazard ratio 27.49, 95% confidence interval: 4.66-162.10, p<0.001) was an independent predictor of cardiac events., Conclusions: These data indicate that insulin resistance associated with compensatory hyperinsulinemia increases the risk of cardiac events in VSA patients., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Variant angina is a form of angina pectoris that shows transient ST-segment elevation on electrocardiogram during an attack of chest pain. Ischemic episodes of variant angina show circadian variation and often occur at rest from midnight to early morning. Ischemic episodes also occur during mild exercise in the early morning. However, they are not usually induced by strenuous exercise in the afternoon. Other important clinical features of variant angina include the high frequency of asymptomatic ischemic episodes and the syncope that sometimes occur during the ischemic episodes. Syncope is due to severe arrhythmias, including ventricular tachycardia, ventricular fibrillation, and high-degree atrioventricular block. Coronary artery spasm is the mechanism of ischemic episodes in variant angina. The incidence of coronary artery spasm shows a racial difference and is higher in Japanese than in Caucasians. Coronary arteriograms are normal or near-normal in most Japanese patients with variant angina. Deficient basal release of nitric oxide (NO) due to endothelial dysfunction, and enhanced vascular smooth muscle contractility with the involvement of the Rho/Rho-kinase pathway are reported to play important roles in the pathogenesis of coronary artery spasm. Other precipitating factors of coronary artery spasm include imbalance in autonomic nervous activity, increased oxidative stress, chronic low-grade inflammation, magnesium deficiency, and genetic susceptibility. The genetic risk factors associated with coronary artery spasm include gene polymorphisms of endothelial NO synthase (NOS), paraoxonase, and other genes. Calcium channel blockers are extremely effective in preventing coronary spasm. The long-acting nitrate, nicorandil, and Rho-kinase inhibitor are also useful for inhibiting coronary artery spasm. Because variant angina can lead to acute myocardial infarction, fatal arrhythmias, and sudden death, early treatment is important. The prognosis of patients with variant angina is favorable, if early complications can be overcome. However, because coronary artery spasm cannot be suppressed in some patients, even with multiple medications, medications to suppress intractable coronary artery spasm must be developed.

Background: Nitrates have been widely used as anti-ischemic drugs in patients with vasospastic angina (VSA). However, the effect of long-term nitrate treatment on cardiac events in VSA patients remains unclear., Methods and Results: Two-hundred and thirty-one patients with VSA who had not been receiving any antiischemic drugs, including calcium channel blockers (CCBs), nitrates, nicorandil, or any combination of these medications were prospectively enrolled in the present study. All patients had a positive acetylcholine provocation test with normal coronary angiograms, and they received CCBs after enrollment. They were divided into 2 groups based on whether nitrates were included in the treatment: a nitrate group (n=86) and a without nitrate group (n=145). The baseline clinical characteristics and frequency of anginal attacks within 48h before enrollment were similar between the 2 groups. With a median follow-up period of 70.5 months, 29 patients developed cardiac events, including 7 sudden cardiac deaths and 22 re-admissions for acute coronary syndrome. Cardiac events occurred in 19.8% of the nitrate group and in only 8.3% of the patients who were not taking nitrates (P=0.015). In a multivariate analysis, long-term nitrate treatment (hazard ratio 5.18, 95% confidence interval: 1.69-15.89, P=0.004) was an independent predictor of cardiac events., Conclusions: These data indicate that long-term nitrate treatment in addition to CCBs might not reduce cardiac events in VSA patients.

Background: The Rho/Rho-kinase signaling pathway is known to be involved in the pathogenesis of coronary artery spasm. Previous studies reported the efficacy of the Rho-kinase inhibitor, fasudil, in the prevention and relief of coronary spasm. The usefulness of fasudil in combination with conventional vasodilating agents, however, has not been fully examined in patients with vasospastic angina., Methods and Results: A total of 26 patients (mean age, 61+/-11 years) with documented vasospasm in the left anterior descending coronary artery were examined by the acetylcholine stress test. Coronary diameter at the spasm site was measured at baseline and after the administration of vasodilator agents in the following order: intracoronary nitroglycerin (NTG) (300 microg), intravenous fasudil (30 mg, n=15, fasudil group) or saline (n=11, saline group), and again NTG during coronary angiography. The increase in diameter observed following the first NTG administration was found to be similar in the fasudil and saline groups (38.3+/-23.5% and 42.3+/-17.1%, respectively). The additional change in diameter on fasudil treatment (16.9+/-11.2% increase over the diameter after the first NTG administration) was significantly larger than that with saline (-2.8+/-7.6%, P<0.001). The second administration of NTG did not affect the diameter of the spasm site in either group., Conclusions: Fasudil further dilated the site of coronary spasm, which had already been treated with NTG in patients with vasospastic angina. These findings support and extend the previous results that showed the feasibility of employing fasudil as a novel therapeutic approach for coronary spasm.

A 54-year-old man was admitted to our hospital for evaluation of chest pain occurring at rest in the morning. ST segment depression was observed during a treadmill exercise test. Coronary angiography identified spontaneous spasm of the proximal right coronary artery, and right coronary obstruction was improved from 90% to about 50% stenosis after intracoronary administration of nitroglycerin. Myocardial iodine-123 beta-methyl-p-iodophenyl-pentadecanoic acid uptake was absent, but thallium-201 uptake during single photon emission computed tomography was normal, and neither platelet nor monocyte expression of the CD36 molecule was observed, indicating type I CD36 deficiency. High blood pressure, elevated plasma triglyceride and fasting plasma glucose levels, and low high-density lipoprotein values suggested metabolic syndrome. The final diagnosis was type I CD 36 deficiency associated with metabolic syndrome and vasospastic angina.

Objectives: The concentration of macrophage colony-stimulating factor (M-CSF), an inflammatory cytokine, increases with the progression of coronary lesions, but no clinical investigations have evaluated the relationship to coronary vascular tone. The present study investigated the relationship between M-CSF and vasoreactivity of the coronary arteries in patients with vasospastic angina., Methods: Vasospastic angina (VSA) was characterized by transient chest pain and ischemic ST segment changes at rest, or by a positive result in spasm provocation testing with acetylcholine. The subjects were 24 patients with stable VSA(inactive VSA group) treated on an outpatient basis, 31 VSA patients hospitalized with unstable angina (active VSA group), and 13 healthy subjects(control group). The sensitivity of determination of plasma M-CSF in blood was 40 pg/ml. The levels of this factor in each group were compared. Based on the findings of the acetylcholine vasospasm-induction test, patients were divided into those with single-vessel vasospasm and those with multivessel vasospasm, and, according to the dose of acetylcholine required to induce spasm, into high- and low-dose groups. Plasma M-CSF levels in each group were compared., Results: Mean plasma M-CSF was 598 +/- 180 pg/ml in the inactive VSA group, 775 +/- 194 pg/ml in the active VSA group, and 632 +/- 103 pg/ml in the control group. The mean plasma M-CSF level in the active VSA group was significantly higher than that in the inactive VSA group(p < 0.01). Mean plasma M-CSF level in the single-vessel and multivessel vasospasm groups was highest for active VSA patients with multivessel vasospasm (872 +/- 173 pg/ml). The relationship with the acetylcholine induction dose clarified that plasma M-CSF levels were highest in patients with active VSA in the acetylcholine low-dose group (825 +/- 177 pg/ml, p < 0.001)., Conclusions: Plasma M-CSF concentration reflects the vasoreactivity of coronary spasm in the VSA group, and may be an indicator of the severity of coronary endothelial dysfunction.

The relationship between autonomic nervous system activity (ANA) and coronary vasoreactivity during transient myocardial ischemia was determined in patients with vasospastic angina (VA). ANA was measured by power spectral analysis of heart rate variability and humoral factors following intravenous infusion of insulin in 24 patients with VA and 6 control patients. Nine (38%) of the VA patients had significant ST segment depression (STD), and 4 of these patients had symptomatic STD. The frequency of anginal episodes in the 9 patients with VA and STD was significantly greater than that in the 15 VA patients without STD (3.4 +/- 3.1 vs 0.5 +/- 0.8 episodes/week, p < 0.05). The increase in the LF/HF ratio 30 min after insulin injection in patients with STD was significantly greater than that in patients without STD (34 +/- 31% vs 4 +/- 34%, p < 0.05). All of the patients with VA and STD had significant coronary vasospasm in response to the infusion of < or = 20 micrograms of acetylcholine, higher levels of nocturnal parasympathetic activity, and greater norepinephrine production in response to insulin stimulation than the VA patients without STD. These findings suggest that increased vagal tone and hyperreactivity to adrenergic stimulation may trigger vasospasm in patients with VA.

Myocardial bridge (MB) is a congenital anomaly of the coronary artery and may occur in 5 to 12% of the human population. However, the mechanism of MB-induced myocardial ischemia is still speculative. We report 2 cases of variant form angina pectoris associated with MB in which myocardial ischemia seemed to be related to the interaction between coronary perfusion and MB. In case 1, electrocardiography during anginal attack at rest showed ST elevation in the inferior leads and MB was observed after percutaneous transluminal coronary angioplasty at the site of the right coronary artery lesion following successful dilatation. In case 2, MB of the left anterior descending coronary was located in the identical portion where coronary vasospasm was induced by intracoronary acetylcholine injection, although ischemia during the spontaneous anginal attack was limited to the inferior area of myocardium. These 2 cases suggest that MB can be, at least in some patients, one of the possible causes of the endothelial damage which seems to be related to coronary vasospasm; this was documented in both cases.

The effects of drugs were evaluated in 47 cases with variant angina (VA), 19 with resting angina showing ST depression (RA), and 84 with unstable angina (UA). In VA patients, calcium antagonists were effective in 87.1% of the cases, while other drugs were effective in 56.3%. The difference was statistically significant. In RA patients, calcium antagonists were effective in 80.0% of the cases and other drugs in 44.4%. Nifedipine was effective in all 5 cases with coronary stenosis of more than 75.0%. All cases of RA had multiple vessel disease and nifedipine was effective in 80.0% of the patients. Nifedipine was effective in 83.3% of VA cases showing ST elevation during an exercise test, and was particularly effective in all patients having attacks only at rest. The effects of nifedipine were confirmed in 83.3% of UA cases. These results indicate that calcium antagonists are effective in VA, RA, and UA.