Low responsiveness to thienopyridine in hemodialysis patients.

We sought to evaluate whether thienopyridine low responsiveness, a predictor of stent thrombosis, is found in hemodialysis patients. We measured platelet aggregation at the site of implantation of drug-eluting stents in 333 patients with angina pectoris undergoing dual anti-platelet therapy. Thirty-one patients were on hemodialysis (HD group), and 302 were not (N-HD group). We used a novel whole-blood aggregometer. The aggregometer used the screen filtration method, with adenosine diphosphate as an agonist. The concentration of agonist required to induce 50% of the maximum pressure rate was calculated and indicated as the platelet aggregatory threshold index (PATI). Low responsiveness for thienopyridine was defined if the PATI levels were <4 µmol/l. PATI levels (µmol/l) were significantly lower in the HD group than in the N-HD group (6.8 ± 4.8 vs. 9.1 ± 5.4, P = 0.023), and the rate of low responsiveness for thienopyridine was significantly higher in the HD group than in the N-HD group (45.7 vs. 26.8%, P = 0.019). Non-fatal myocardial infarction and stent thrombosis occurred in three of the HD group and in nine of the N-HD group (P = 0.122). Late stent thrombosis occurred at a significantly higher rate in the HD group than in the N-HD group (P = 0.002). The rate of target lesion revascularization was significantly higher in the HD group than in the N-HD group (38 vs. 11.8%, P = 0.0001). In conclusion, low responsiveness to thienopyridine, as an indicator of platelet reactivity, is found more frequently in hemodialysis patients.

Sorafenib-induced acute myocardial infarction due to coronary artery spasm.

A 65-year-old man with advanced renal cell carcinoma was admitted due to continuing chest pain at rest. Two weeks before his admission, sorafenib had been started. He was diagnosed with non-ST-elevation myocardial infarction by laboratory data and electrocardiogram. Enhanced heart magnetic resonance imaging also showed subendocardial infarction. However, there was no stenosis in coronary arteries on angiography. Coronary artery spasm was induced by a provocative test. Cessation of sorafenib and administration of Ca-channel blocker and nitrates ameliorated his symptoms, but relapse occurred after resumption of sorafenib. Addition of oral nicorandil reduced his symptoms and maintained stable angina status. We report the first case of sorafenib-induced coronary artery spasm. Sorafenib is a multikinase inhibitor that targets signaling pathways necessary for cellular proliferation and survival. On the other hand, the Rho/ROCK pathway has an important role in the pathogenesis of coronary artery spasm. Our report may show an adverse effect on the Rho/ROCK pathway by sorafenib use.

Pravastatin improved glucose metabolism associated with increasing plasma adiponectin in patients with impaired glucose tolerance and coronary artery disease.

Reduced incidence of type-2 diabetes has been shown in patients treated with pravastatin. Adiponectin can exhibit beneficial effects on glucose metabolism. We investigated whether pravastatin could improve glucose tolerance associated with increasing adiponectin levels in patients with impaired glucose tolerance (IGT). This study consisted of 40 coronary artery disease (CAD) patients with IGT assessed by oral glucose tolerance test (OGTT). Patients were randomized to receive pravastatin (n=20) or no lipid-lowering medications (control group, n=20) for 6 months, after which OGTT was repeated and adiponectin levels were measured. Pravastatin treatment significantly decreased levels of total cholesterol (16%), low-density lipoprotein cholesterol (23%) and high-sensitivity C-reactive protein (37%) (p<0.01, respectively). At 2h in OGTT, pravastatin significantly improved hyperglycemia (-14%) and hyperinsulinemia (-23%). Pravastatin treatment significantly elevated plasma adiponectin levels (35%; p<0.001) but not in the control group. The glucose reduction at 2h post-OGTT was significantly associated with increased levels of adiponectin (r=-0.462; p=0.003). Pravastatin treatment is an independent predictor for improvement of post-loaded hyperglycemia (odds ratio; 5.7; 95% confidence interval 1.7-19.3; p=0.003) and achieved beneficial conversion from IGT to normal glucose tolerance (40%; p=0.03). Pravastatin exhibits beneficial effects on glucose metabolism especially in the postprandial state associated with increasing plasma adiponectin levels in CAD patients with IGT.

Prognostic value of flow-mediated dilation of the brachial artery in patients with cardiovascular disease.

OBJECTIVE: Endothelial dysfunction is thought to represent the initial stage in the development of atherosclerosis. Recently, noninvasive examination of endothelial function has become possible using flow-mediated endothelium-dependent dilation of the brachial artery (FMD) during reactive hyperemia. We examined whether FMD has prognostic value for the prediction of subsequent cardiovascular events. METHODS: Patients were followed prospectively every month until the occurrence of the cardiovascular events. PATIENTS: The study subjects comprised 221 consecutive patients (men 108, mean age 61.4+/-10.6, ischemic heart disease 152, cardiomyopathy 28, arrhythmia 12, valvular disease 5, congenital heart disease 3, and cardioneurosis 21). The mean FMD was 4.77+/-2.85% and this value was used to divide the patients into the 2 groups (Group 1: FMD > or =4.7%; Group 2: FMD <4.7%). RESULTS: There were 110 patients in Group 1 (men 36, mean age 60.5+/-10.9), and 111 patients in Group 2 (men 72, mean age 62.2+/-10.3). Patients were followed until the occurrence of at least 1 of the major clinical cardiovascular events. Seven cardiovascular events occurred in Group 1 (6.4%, 1.14 events per 100 patient-years), while 16 occurred in Group 2 (2.88 events per 100 patient-years). Kaplan-Meier analysis demonstrated a significantly higher probability of developing cardiovascular events in Group 2 than in Group 1. CONCLUSION: The present results demonstrated that the magnitude of FMD in the brachial artery was a good predictor of subsequent cardiovascular events.

Subacute thrombosis after coronary stenting occurring with resistance to ticlopidine.

A 79-year-old man underwent stent implantation from the proximal site to the left main trunk with one bare metal stent after rotation atherectomy. He received 200 mg/day ticlopidine and 200 mg/day aspirin from 2 days pre-stenting. Subacute thrombosis occurred 5 days after coronary stenting. We performed a test of platelet aggregation one month after the commencement of dual antiplatelet therapy and the test showed no response to ticlopidine in this case. An increased dose of ticlopidine was not effective for suppressing platelet aggregation. We report a case of subacute stent thrombosis which is related to ticlopidine resistance.

Elevated levels of remnant lipoproteins are associated with plasma platelet microparticles in patients with type-2 diabetes mellitus without obstructive coronary artery disease.

AIMS: Platelets participate in the pathogenesis of arterial thrombosis and it has been demonstrated that enhanced platelet activation occurs in patients with diabetes mellitus (DM). Dyslipidaemia is a common feature of diabetes. We investigated the association between certain lipid fractions and plasma platelet-derived microparticle (PMP) levels in patients with type-2 DM. METHODS AND RESULTS: We measured fasting serum levels of remnant-like lipoprotein particles-cholesterol (RLP-cholesterol) and assessed in vivo platelet activation by quantifying the number of PMP in the plasma detected as CD42b-positive microparticles by flow cytometry in Japanese type-2 DM patients without obstructive coronary artery disease who were more slender when compared with Western diabetic patients. The levels of total cholesterol, triglycerides, RLP-cholesterol, and plasma glucose were significantly higher in patients with type-2 DM (n = 105) than in non-diabetic patients (n = 92). The plasma levels of PMP were elevated significantly in type-2 DM patients when compared with non-diabetic control subjects [7.41(5.39-10.50) x 10(6) vs. 3.44(2.43-4.41)x10(6), P < 0.001]. We found that RLP-cholesterol levels were the best predictor of PMP in multivariable linear regression analyses (beta = 0.375, P < 0.001). Lipid-lowering medication with bezafibrate successfully reduced levels of both RLP-cholesterol and PMP in patients with type-2 DM (P < 0.05). CONCLUSIONS: RLP-cholesterol and platelet microparticles are both elevated in type-2 DM patients when compared with controls. RLP-cholesterol is the primary and only predictor of platelet microparticles in the multivariable analysis, which include several standard atherosclerosis risk factors. This suggested that reducing elevated RLP-cholesterol with lipid-lowering therapy may be an effective strategy to prevent thrombogenic vascular complications in type-2 DM.

Stabilization of carotid atheroma assessed by quantitative ultrasound analysis in nonhypercholesterolemic patients with coronary artery disease.

OBJECTIVES: This study examined whether intensive cholesterol-lowering therapy with statins in nonhypercholesterolemic patients is effective in improving echolucency of vulnerable plaques assessed by ultrasound with integrated backscatter (IBS) analysis. BACKGROUND: Atherosclerotic plaque stabilization is a promising clinical strategy to prevent cardiovascular events in patients with coronary artery disease (CAD). There is a correlation between coronary and carotid plaque instability, and echolucent plaques are recognized as vulnerable plaques. METHODS: Consecutive nonhypercholesterolemic patients with CAD were randomly assigned Adult Treatment Panel-III diet therapy (diet group; n = 30) or pravastatin (statin group; n = 30). Echolucent carotid plaques were monitored by measuring intima-media thickness (IMT) and echogenicity by IBS for six months. RESULTS: Total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-sensitivity C-reactive protein were significantly decreased in the statin group (from 197 +/- 15 mg/dl to 170 +/- 18 mg/dl [p < 0.001]; from 131 +/- 14 mg/dl to 99 +/- 14 mg/dl [p < 0.001]; and from 0.11 [0.04 to 0.22] mg/dl to 0.06 [0.04 to 0.11] mg/dl [p < 0.05]; respectively), whereas only total cholesterol was moderately reduced (from 193 +/- 24 mg/dl to 185 +/- 22 mg/dl [p < 0.05]) and LDL-C and triglycerides insignificantly reduced in the diet group. Significant increases of echogenicity of carotid plaques were noted in the statin group but not in the diet group (from -18.5 +/- 4.1 dB to -15.9 +/- 3.7 dB [p < 0.001] and from -18.2 +/- 4.0 dB to -18.9 +/- 3.5 dB [p = 0.13]; respectively) without significant regression of plaque-IMT values in both groups. CONCLUSIONS: Statin therapy is rapidly effective in increasing echogenicity of vulnerable plaques without regression of plaque size in nonhypercholesterolemic patients with CAD. Quantitative assessment of carotid plaque quality by ultrasound with IBS is clinically useful for monitoring atherosclerotic lesions by evaluating vulnerability of atheroma.

Elevated levels of VE-cadherin-positive endothelial microparticles in patients with type 2 diabetes mellitus and coronary artery disease.

OBJECTIVES: The purpose of this study was to examine whether CD144-EMP (endothelium-derived microparticles) is useful as a specific marker of endothelial cell (EC) dysfunction and to determine whether plasma levels of circulating CD144-EMP predicted coronary artery disease (CAD) in patients with type 2 diabetes mellitus (DM). BACKGROUND: Endothelial cell dysfunction is involved in atherogenesis; however, the quantitative assessment of EC dysfunction has yet to be established clinically. Endothelium-derived microparticles are small, membrane-shed vesicles that are generated from the EC surface in response to cellular dysfunction and/or injury. Diabetes mellitus is known to be associated with EC dysfunction and accelerated atherosclerosis. METHODS: We characterized EMP using anti-CD144 (VE-Cadherin) antibody in various atherosclerosis-related cells and investigated the association between the levels of CD144-positive microparticles and hydrogen-peroxide-induced EC injury and acetylcholine-induced coronary vasomotion. Furthermore, we evaluated plasma CD144-EMP levels in patients with and without DM. RESULTS: We demonstrated that CD144-positive microparticles were derived selectively from human EC. The levels of CD144-EMP reflected the degree of in vitro hydrogen-peroxide-induced EC injury and impairment of in vivo endothelium-dependent coronary vasodilation (p < 0.01). Plasma CD144-EMP levels were increased significantly in DM patients compared with patients without DM (p < 0.001). In DM patients, the elevated levels of CD144-EMP were the most significant risk factor for CAD relative to all other traditional risk factors (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.8 to 6.9, p < 0.001). Notably, plasma CD144-EMP identified a subpopulation of established CAD patients in DM subjects without typical anginal symptoms (OR 10.6, 95% CI 3.9 to 29.5, p < 0.001). CONCLUSIONS: The CD144-positive EMP exist in human plasma, and plasma CD144-EMP levels can be a clinically specific and quantitative marker of EC dysfunction and/or injury. Measurement of CD144-EMP, by providing a quantitative assessment of EC dysfunction, may be useful for identifying DM patients with increased risk of CAD.

Prognostic value of remnant-like lipoprotein particle levels in patients with coronary artery disease and type II diabetes mellitus.

OBJECTIVES: This study prospectively examined whether the levels of high remnant-like lipoprotein particles (RLP) cholesterol have a significant risk and influence prognosis in patients with coronary artery disease (CAD) and type II diabetes mellitus (DM). BACKGROUND: Several studies have shown that triglyceride-rich lipoproteins contribute to atherosclerotic complications in type II DM. However, it remains to be established which triglyceride-rich lipoproteins contribute to this risk. METHODS: Levels of RLP cholesterol in fasting serum were measured by an immunoseparation method in 240 type II DM patients with (n = 120) or without (n = 120) CAD. The patients with CAD were followed up for a period of < or =24 months until the occurrence of one of the following clinical coronary events: re-admission or coronary revascularization due to recurrent or refractory angina pectoris, nonfatal myocardial infarction, or cardiac death. RESULTS: Patients with CAD had higher RLP levels than patients without CAD. Multivariate logistic regression analysis showed that high RLP cholesterol levels (>4.7 mg cholesterol/dl, representing the 75th percentile of the distribution of RLP cholesterol levels in control subjects) were a significant risk factor for the presence of CAD, independent of traditional risk factors. Kaplan-Meier analysis demonstrated that higher RLP cholesterol levels in patients with CAD resulted in a significantly higher probability for the development of coronary events. Multivariate Cox hazards analysis showed that high RLP cholesterol levels in patients with CAD were a significant predictor of future coronary events, independent of other risk factors. CONCLUSIONS: Increased levels of RLP cholesterol are a significant and independent risk factor of CAD and predict future coronary events in patients with CAD and type II DM.

Echolucent carotid plaques predict future coronary events in patients with coronary artery disease.

OBJECTIVES: The purpose of this study was to examine whether echolucent carotid plaques predict future coronary events in patients with clinically stable coronary artery disease (CAD). BACKGROUND: Although rupture of coronary plaques is considered a major cause of acute coronary syndromes (ACS), the clinical estimation of coronary vulnerability still remains inconclusive. Ultrasound evaluation of carotid plaques with integrated backscatter (IBS) analysis can indicate the consistency/structure of the plaques. Lipid-rich lesions known as "unstable plaques" appear as echolucent plaques with low IBS values using this technique. METHODS: We investigated the echogenicity of carotid plaques using ultrasound with IBS in 286 consecutive CAD patients (71 with ACS and 215 with stable CAD). Coronary plaque complexity was also determined angiographically in stable CAD patients followed up for 30 months or until the occurrence of coronary events. RESULTS: The calibrated IBS values of carotid plaques in ACS patients were significantly lower than those in stable CAD patients (p < 0.01). Echolucent carotid plaques accurately predicted the existence of complex coronary plaques (predictive power of 83%). Kaplan-Meier analysis demonstrated a significantly higher probability of coronary events developing in patients with echolucent carotid plaques than in patients without this type of plaque (p < 0.001). The presence of echolucent carotid plaques in stable CAD patients predicted future coronary events independent of other risk factors (odds ratio 7.0, 95% confidence interval 2.3 to 21.4; p < 0.001). CONCLUSIONS: Echolucent carotid plaques with low IBS values predicted coronary plaque complexity and the development of future coronary complications in patients with stable CAD. Qualitative evaluation of carotid plaques using ultrasound with IBS is a clinically useful procedure for risk assessment of CAD patients.

Association of polymorphism in glutamate-cysteine ligase catalytic subunit gene with coronary vasomotor dysfunction and myocardial infarction.

OBJECTIVES: The purpose of this study was to test the hypothesis that polymorphisms in the promoter region of the glutamate-cysteine ligase catalytic subunit (GCLC) gene may be associated with coronary endothelial vasomotor dysfunction and myocardial infarction (MI). BACKGROUND: Glutamate-cysteine ligase is a rate-limiting enzyme for synthesis of glutathione (GSH) that plays a crucial role in the intracellular antioxidant defense systems. Oxidants transcriptionally upregulate the GCLC gene for GSH synthesis, providing a protective mechanism against oxidant-induced endothelial dysfunction or activation, which plays a pathogenetic role in cardiovascular diseases. METHODS: The association of the possible polymorphisms with coronary arterial diameter responses to acetylcholine was determined in 62 male subjects. The frequency of polymorphisms was compared between 255 male patients with MI and 179 male control subjects. RESULTS: We found a polymorphism (-129C/T) in which the T allele showed lower promoter activity (50% to 60% of the activity of the C allele) in response to H(2)O(2) in human endothelial cells. Endothelium-dependent dilation of coronary arteries was impaired in subjects with the -129T allele (n = 31), as compared with the age-matched subjects without the -129T allele (n = 31). The T allele was highly frequent in patients with MI as compared with control subjects, and it was a significant risk factor for MI, independent of traditional coronary risk factors (odds ratio [OR] 1.81, 95% confidence interval [CI] 1.08 to 3.03; p = 0.03). CONCLUSIONS: The -129T polymorphism of the GCLC gene may suppress the GCLC gene induction response to an oxidant, and it is implicated in coronary endothelial vasomotor dysfunction and MI.

Polymorphism in the 5'-flanking region of human glutamate-cysteine ligase modifier subunit gene is associated with myocardial infarction.

BACKGROUND: Human glutamate-cysteine ligase (GCL) is a rate-limiting enzyme for the synthesis of glutathione that plays a crucial role in antioxidant defense mechanisms in most mammalian cells, including vascular cells. Oxidants transcriptionally upregulate GCL genes for glutathione synthesis, providing a protective mechanism against oxidative stress-induced cellular dysfunction. This study examined the hypothesis that variation in the GCL genes may be associated with coronary artery disease in which oxidative stress plays a pathogenetic role. METHODS AND RESULTS: We searched for the common variants in the 5'-flanking region of the GCL modifier subunit (GCLM) gene in patients with myocardial infarction (MI). We found a polymorphism (-588C/T) in which the T allele showed lower promoter activity (40% to 50% of C allele) in response to oxidants in the luciferase reporter gene assay. Allele frequencies were determined by polymerase chain reaction-based analysis of restriction fragment length polymorphism in 429 patients with MI and 428 control subjects (as defined by angiography) in Kumamoto Prefecture, Japan. The frequency of the T polymorphism was significantly higher in the MI group than in the control group (CT and TT genotypes: 31.5% in MI group versus 19.2% in control group; P<0.001). In multiple logistic regression analysis, the T polymorphism was a risk factor for MI independent of traditional coronary artery disease risk factors (odds ratio, 1.98; 95% confidence interval, 1.38 to 2.83; P<0.001). CONCLUSIONS: These findings suggest that the -588T polymorphism of the GCLM gene may suppress GCLM gene induction in response to oxidants and that it is a genetic risk factor for MI.

Conduction properties of the crista terminalis and its influence on the right atrial activation sequence in patients with typical atrial flutter.

The conduction properties of the crista terminalis (CT) and its influence on the right atrial activation sequence were analyzed in 14 patients with typical atrial flutter (AF). Atrial mapping was performed with 35 points of the right atrium during typical AF and during atrial pacing performed after linear ablation of inferior vena cava-tricuspid annulus (IVC-TA) isthmus. Atrial pacing was delivered from the septal isthmus at cycle lengths of 600 ms and the tachycardia cycle length (TCL). The right atrial activation sequence and the conduction interval (CI) from the septal to lateral portion of the IVC-TA isthmus were analyzed. During AF, the conduction block line (CBL) (detected by the appearance of double potentials along the CT and craniocaudal activation on the side anterior to CT) was observed along the CT in all patients. The TCL and CI during AF were 254 +/- 19 and 207 +/- 14 ms, respectively. During pacing at a cycle length of 600 ms, the CBL was observed along the CT in four patients, however, a short-circuiting activation across the CT was observed in the remaining ten patients. The CI during pacing at 600 ms was 134 +/- 38 ms, shorter than that during AF (P < .0001). During pacing at the TCL, the CBL was observed along the CT in all patients. The presence of the CBL along the CT prevented a short-circuiting activation across the CT and resulted in the same right atrial activation as observed during AF. With the formation of the CBL, the CI significantly increased to 206 +/- 17 ms and was not different from that during AF. These data suggest that the conduction block along the CT is functional. It was presumed that presence of conduction block at the CT has some relevance to the initiation of typical AF though it was not confirmed.