Effect of glycemic state on postprandial hyperlipidemia and hyperinsulinemia in patients with coronary artery disease

Both postprandial hyperlipidemia and hyperinsulinemia have been thought to play an important role in the development of atherosclerosis, and to be a potent risk factor for cardiovascular event. To examine effects of glycemic state on postprandial hyperlipidemia and hyperinsulinemia in patients with coronary artery disease (CAD), a total of 112 consecutive male patients with angiographically confirmed CAD were loaded with a high-fat and high-glucose test meal. CAD patients were divided into three groups as “non-diabetic”, “prediabetic”, and “diabetic” CAD groups. The serum triglyceride (TG) and remnant-like particle cholesterol (RLP-C) levels at the 6th hour in diabetic CAD group showed significantly higher than non-diabetic CAD group, and the incremental area under the curves (iAUCs) of these levels in diabetic CAD group were significantly greater than non-diabetic CAD group (TG, P = 0.0194; RLP-C, P = 0.0219). There were no significant differences in the iAUCs of TG or RLP-C between prediabetic and non-diabetic CAD group. The AUCs of plasma insulin levels or insulin resistance index (IRI): (AUCs of insulin) × (AUCs of glucose) as the insulin resistance marker were greater in diabetic CAD group than non-diabetic CAD group (insulin, P = 0.0373; IRI, P = 0.0228). The AUCs of serum TG or RLP-C levels showed a correlation with the AUCs of plasma insulin (AUC-TG, r = 0.5437, P < 0.0001; AUC-RLP-C, r = 0.6847, P < 0.0001), and they correlated well with the insulin resistance index (AUC-TG, r = 0.7724, P < 0.0001; AUC-RLP-C, r = 0.7645, P < 0.0001). We found that the insulin resistance showed a close relationship with postprandial hyperlipidemia in CAD patients. Diabetic, but not prediabetic state, may be a risk for postprandial impaired lipid metabolism in CAD patients.     

Features of myocardial metabolism of some amino acids and ammonia in patients with coronary artery disease

Fractional myocardial extraction/release of glutamate, glutamine, alanine, ammonia, asparagine, glucose and lactate was studied in 12 subjects with normal coronary anatomy (controls) and 28 patients with coronary artery disease (CAD) during rest and atrial pacing. At rest patients with CAD showed an increased myocardial extraction of glutamate, glucose and lactate and an augmented glutamine and alanine release compared with controls. In all CAD patients myocardial ammonia and asparagine release was found at rest, while all controls showed myocardial extraction of these compounds. Myocardial glutamate extraction correlated positively with glucose and lactate extraction, glutamine and alanine release and inversely with ammonia release in CAD patients at rest. In patients with two- and three-vessel disease pacing-induced ischaemia resulted in a pronounced decrease in myocardial glutamate extraction and glutamine release, augmented myocardial production of ammonia and asparagine and a conversion of lactate extraction into lactate release. During pacing myocardial glutamate extraction was related to alanine and glutamine release and correlated inversely with ammonia and lactate release in these patients. The results indicate that glutamate extraction is closely connected with glucose and lactate extraction and ammonia binding via glutamine formation in the hearts of CAD patients and, thus, with the energy supply of ischaemic myocardium. An assessment of myocardial exchange of the nitrogenous compounds we have studied, complimentary to lactate, is a promising biochemical test for the identification of ischaemic heart disease in man.     

Effect of free fatty acid inhibition on silent and symptomatic myocardial ischemia in diabetic patients with coronary artery disease

ObjectiveFree fatty acid inhibition with trimetazidine (TMZ) improves myocardial metabolism and myocardial ischemia in patients with coronary artery disease (CAD). Because of its effect on myocardial glucose utilization TMZ may represent a therapeutic option in diabetic patients with CAD. Aim of the present study was to evaluate whether the metabolic effect of TMZ may improve episodes of myocardial ischemia in diabetic patients with CAD.Research design and methodsWe assessed the effect of TMZ on 24 h ambulatory ECG monitoring (AEM) in 30 patients (22 males and 8 females, mean (SE) age 67 ± 6.5 years) with NIDDM and ischemic cardiomyopathy. Patients were randomized to receive on top of standard therapy either TMZ (20 mg, tds) or placebo (tds) and were evaluated at baseline and after 6 months.ResultsPatients randomized to TMZ or placebo were comparable regarding demographic data, distribution of CAD, and glicated haemoglobin levels. TMZ significantly reduced the number of episodes of transient myocardial ischemia (− 24% compared to baseline, p < 0.01; − 27% compared to placebo, p < 0.01), and Total Ischemic Burden (− 28% compared to baseline, p < 0.01; − 29% compared to placebo, p < 0.01). TMZ also significantly reduced the number of silent episodes of myocardial ischemia (− 42% compared to baseline and − 39% compared to placebo, p < 0.01) and the time of silent myocardial ischemia/24 h (− 37% compared to baseline and − 35% compared to placebo, p < 0.01). No significant changes in heart rate were detected between baseline, placebo and TMZ evaluations.ConclusionsTMZ is effective in reducing silent and symptomatic episodes of transient myocardial ischemia in diabetic patients with CAD on standard anti-anginal therapy.     

超声心肌声学造影评价冠状动脉狭窄程度对心肌灌注的影响

目的经冠状动脉超声心肌声学造影(MCE)检测基础状态下不同狭窄程度冠状动脉所供应心肌组织灌注状况。方法30例患者行选择性冠状动脉造影,按有无冠状动脉病变及病变血管狭窄程度,将所涉及的共93个心肌节段分为对照组(18个)和病变组(75个),其中病变组又分为轻度狭窄组(12个)、中度狭窄组(28个)、重度狭窄组(35个);超声声学造影剂由冠状动脉直接注入,完成MCE。对心肌灌注进行定性分析,并由心肌灌注时间强度曲线进行定量分析。结果112个心肌节段中有93个(83.0%)获得较满意图像,经视觉判断,病变组共75个心肌节段中,正常灌注的为58个(77.3%),低灌注为17个(22.7%),其中,轻度狭窄组均为正常心肌灌注。定量分析显示,重度狭窄组反映心肌灌注的3个参数值与对照组均存在明显差异(P<0.05);而轻、中度狭窄组各参数值与对照组无明显差异。结论基础状态下,狭窄程度>90%的冠状动脉病变,其心肌组织灌注水平较正常偏低;而当血管狭窄程度≤90%时,心肌灌注水平与正常相似。     

Exercise-induced myocardial ischemia in patients with coronary artery ectasia without obstructive coronary artery disease

BACKGROUND: Aetiology, clinical significance and treatment options for coronary artery ectasia/aneurysm is not clear. OBJECTIVE: We sought to determine whether exercise can induce coronary ischemia in patients with coronary artery ectasia/aneurysm without significant coronary stenosis. METHODS: Coronary artery ectasia was defined as 1.5-2-fold, aneurysm as >2-fold luminal dilatation of the adjacent normal segment. The study patients could have irregularities with ectatic coronaries but they did not have stenotic lesions >50% with visual assessment of two blinded observers. Patients having coronary artery ectasia or aneurysm with prior myocardial infarction, dilated cardiomyopathy, valvular heart disease, bundle branch block, significant ST-T changes were excluded. The control group was formed from a well matched population of 32 patients with normal coronary arteries who have not performed a treadmill test before coronary angiography. The study group underwent a symptom limited treadmill test if they did not have one before coronary angiogram, all control patients underwent treadmill test. RESULTS: Thirty-three patients with coronary artery ectasia/aneurysm (ranging from one to three vessels) but without significant stenosis were derived from 4470 cardiac catheterization procedures between January 1998 and July 2000. In the study group, 17 of the patients had positive treadmill tests with respect to five patients in the control group (P = 0.004). In subgroup analysis, diffuse ectasia/aneurysm (involving 2-3 vessels) was found to be strongly related with ischemia (P = 0.005) with respect to local disease. CONCLUSION: Coronary artery ectasia/aneurysm may lead to exercise induced ischemia, especially in the diffuse form.     

Effect of digoxin on coronary blood flow and myocardial oxygen consumption in patients with chronic coronary artery disease

In 10 patients with chronic coronary artery disease and without clinical evidence of congestive heart failure, the effects of 1.0 mg of digoxin intravenously on systemic hemodynamics, coronary blood flow, myocardial oxygen consumption and myocardial lactate extraction were studied both at rest and during atrial pacing. Atrial stimulation at a rate just below the threshold for angina led to a significant decrease in left ventricular enddiastolic pressure, from 10.6 ± 1.6 to 7.1 ± 0.8 mm Hg, associated with a significant decrease in left ventricular stroke work index per beat, from 76.7 ± 5.11 to 40.3 ± 4.01 g-m/m². After digoxin, nearly identical results in stroke work index could be observed at rest and during stimulation (75.2 ± 6.74 and 44.1 ± 5.92, respectively). However, left ventricular enddiastolic pressure decreased significantly before and during atrial stimulation (8.1 ± 1.29 and 4.7 ± 1.09 mm Hg, respectively). Cardiac index decreased from 3.08 ± 0.20 to 2.73 ±0.17 liters/min per m² at rest but during pacing it no longer differed before and after digoxin (3.17 ± 0.22 and 3.10 ± 0.20 liters/min per m², respectively). Myocardial oxygen consumption and lactate extraction remained unchanged after digoxin both at rest and during atrial pacing.It is concluded that some deficiency in left ventricular function is present in patients with chronic coronary artery disease even without clinical evidence of congestive heart failure. Digoxin improves left ventricular performance at rest and during stress conditions. An expected increase in myocardial oxygen consumption due to enhanced contractility is completely counterbalanced, probably by a decrease in left ventricular volume after digoxin.     

Sauna-induced myocardial ischemia in patients with coronary artery disease.

PURPOSE: Sauna bathing is a popular recreational activity that is generally considered to be safe. However, there have been case reports of adverse cardiac events. We sought to determine whether sauna use caused myocardial ischemia in patients with coronary artery disease. METHODS: Sixteen patients with proven coronary artery disease were submitted to three conditions (rest, exercise, and sauna bathing) with continuous electrocardiographic (ECG) monitoring and regular blood pressure measurements. During each condition, patients were injected with Tc-99 sestamibi followed by nuclear scintigraphic imaging. Perfusion defect scores were calculated in 15 patients. RESULTS: Sauna bathing was well tolerated. There was a mean (+/- SD) increase in heart rate of 32% +/- 20% in the sauna (resting mean heart rate = 60 +/- 9 beats per minute vs sauna mean heart rate = 79 +/- 11 beats per minute, P <0.001) and a 13% +/- 6% drop in systolic blood pressure (resting mean systolic blood pressure = 142 +/- 14 mm Hg vs sauna mean systolic blood pressure = 123 +/- 15 mm Hg, P <0.001). There were no arrhythmias or ECG changes in the sauna. Compared with rest, there was significant ischemia during sauna bathing (average perfusion defect score at rest = -0.44 vs average sauna score = -0.93, P <0.001). The perfusion defect score in the sauna was worse than the resting score in 14 of the 15 patients. Sauna-associated perfusion defect scores were highly correlated with exercise-induced scores (R2 = 0.65, P <0.001). CONCLUSION: In patients with stable coronary artery disease, sauna use is clinically well tolerated but is associated with scintigraphically demonstrated myocardial ischemia.     

Effect of long-term exercise training on regional myocardial perfusion changes in patients with coronary artery disease

The cardiac rehabilitation of patients with coronary artery disease (CAD) promotes exercise tolerance, improves left ventricular function, and decreases the heart rate and systolic blood pressure at the same load intensity. Several studies have shown that cardiac rehabilitation improves myocardial perfusion in CAD patients. However, the long-term (> or = 1 year) effect of cardiac rehabilitation on myocardial perfusion is still controversial. The effect of long-term exercise training on myocardial perfusion in CAD patients was assessed using thallium-201 (201Tl) exercise studies at a baseline (4 months after the onset of CAD) and at a 1-year or more follow-up in 58 patients with stable CAD. The subjects had been divided into a training group (n=35) participating in supervised exercise 2 times per week for the follow-up period, and the control group (n=23). There was an improvement in the myocardial perfusion on stress 201Tl scintigraphy in 20 of the 35 (57.1%) trained patients and in 3 of the 23 (13.0%) of the control patients (p<0.001). The number of 201Tl stress myocardial perfusion defect segments was significantly decreased after the cardiac rehabilitation training (231 to 153 segments), but showed no change in the control group (158 to 156 segments) (p<0.01). In spite of no significant differences in the number of involved coronary arteries, it improved (12/17 patients: 70.6%) more in the patients who had trained for more than 2 years compared to the patients who had trained for less than 2 years. The exercise tolerance increased in 25 of the 35 training group patients (71.4%), and in only 3 of the 23 control group patients (13.0%). The peak double products increased from 20,131+/-6,010 to 28,370+/-5,600 (p<0.01) in the training group, and showed no change in the control group (20,567+/-5,112 to 20,964+/-7,728 (NS)). The results indicated that the long-term physical training increased exercise tolerance and the double products of CAD patients. In addition, the training resulted in improved cardiac perfusion as evidenced by 201Tl scintigraphy. The findings suggest that exercise training is an advisable and effective treatment for patients with CAD.     

Effect of rosuvastatin therapy and myocardial revascularization on angiogenesis in coronary artery disease patients

We studied the influence of rosuvastatin therapy and myocardial revascularization on angiogenic growth factors in coronary artery disease (CAD) patients. Two main groups were examined: the first one consisted of patients passed through successful percutaneous coronary intervention (PCI), the second one consisted of patients on 3 months rosuvastatin therapy. Vascular endothelial growth factor (VEGF), VEGF receptor Flt-1 (sVEGF-Rl) and transforming growth factor-beta (TGF-bl) levels were measured in healthy volunteers and CAD patients before and 6 days after myocardial revascularization by PCI. VEGF and basic fibroblast growth factor (bFGF) levels were measured before and 3 month after rosuvastatin therapy, as well as total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDLC), C-reactive protein (CRP), interleukin 6 (IL-6) and endothelium dependent vasodilation. VEGF levels did not differ, but TGF - b levels were significantly lower in CAD patients compared to healthy subjects (11.0 +/- 4.9 pg/ml and 120.0 +/- 32.4 pg/ml, respectively, p < 0.000l). Myocardial revascularization caused changes in VEGF levels from 192.4 +/- 166.1 pg/ml to 264.7 +/- 226.6 pg/ml (p=0.0066) without significant influence on TGF and VEGF-R1 levels in 6 days. There were positive changes in lipid levels, lowering of CRP and IL-6 concentrations, improvement of endothelial function and decrease of VEGF levels from 382 +/- 249 pg/ml to 297 +/- 220 pg/ml (p=0.006) 3 month after start of rosuvastatin treatment (no changes in bFGF levels were observed). Chronic insufficient myocardial blood supply leads to decreasing of TGF - b levels. The elevation of VEGF after myocardial revascularization reflects transient ischemia and potentially may provoke hemodynamic instability, caused by atherosclerotic plaque neovascularization. Strengthening of statin therapy early after myocardial revascularization may allow to stabilize the atherosclerotic plaque condition, also by means of VEGF lowering.     

Effect of acute testosterone on myocardial ischemia in men with coronary artery disease

The effect of acute testosterone administration on exercise-induced myocardial ischemia was assessed in 14 men with coronary artery disease and low plasma testosterone concentrations in a study of randomized, double-blind, crossover design. Testosterone increased time to 1-mm ST-segment depression compared with placebo by 66 (15 to 117) seconds (p = 0.016), suggesting a beneficial effect of testosterone on myocardial ischemia in these patients.     

Silent myocardial ischaemia in patients with angiographically proven coronary artery disease

Twenty patients with angiographically proven coronary artery disease (CAD) were evaluated by Holter monitoring for assessment of total ischaemic burden during daily activities. Thirteen patients revealed ischaemia on Holter monitoring (symptomatic-2, silent-4 and both types-7). As compared to symptomatic ischaemia, the silent myocardial ischaemic episodes were more frequent (25 vs 10 episodes), longer in duration (15-53 minutes vs 8-45 minutes), occurred at lower heart rates (65-75/minute (mean 68) vs 70-90 per minute (mean 76) and silent ischaemic episodes exceeded symptomatic ones in both morning (10 vs 4) and evening (15 vs 6) peaks. Occurrence of symptomatic as well as silent ischaemia had no relation to rest, activity, left ventricular functions, and there was no difference in the extent (1-3mm) and type (horizontal or downsloping) of ST-segment depression. We conclude that in patients with significant coronary artery disease, silent myocardial ischaemia is more frequent than the symptomatic ischaemia during daily activities. It occurs at lower heart rates, lasts longer, and bears no relation to rest, activity or left ventricular function. Evening peaks may be as frequent or more than the morning peaks. Holter monitoring thus is helpful for assessment of total ischaemic burden in CAD patients.     

Nonfatal myocardial infarction in medically treated patients with coronary artery disease

The purpose of this study was to identify patient characteristics associated with nonfatal myocardial infarction as the first event after cardiac catheterization in medically treated patients with coronary artery disease. Multiple logistic risk analyste of 81 baseline characteristics in 354 patients who died or had nonfatal infarction identified 10 characteristics (5 clinical and 5 cardiac catheterization variables) as independently discriminating between the two events. Left ventricular function, specific coronary anatomy, previous myocardial infarction and age were the most important discriminators. Poor left ventricular function and left main coronary stenosis were associated with death. Subtotal left anterior descending and right coronary arterial stenosis, normal hemodynamics, absence of previous infarction and young age were associated with nonfatal infarction. Thus, in any subset of patients who have a uniform risk of ischemic events (nonfatal infarction or death), nonfatal infarction is most likely to occur in those who are young, have had no previous infarction, have subtotal left anterior descending and right coronary arterial stenosis and normal hemodynamics.     

Effects of tadalafil on myocardial blood flow in patients with coronary artery disease

OBJECTIVE: Erectile dysfunction and coronary artery disease share similar risk factors. Although phosphodiesterase-5 inhibitors used to treat erectile dysfunction do not adversely affect hemodynamic parameters in patients with coronary artery disease, their effects on myocardial blood flow are unknown. METHODS: In a randomized, double-blind, crossover study we examined the effects of tadalafil, 20 mg, compared with placebo on myocardial blood flow in patients with stable coronary artery disease (n=7, 52-73 years old). After tadalafil or placebo, myocardial blood flow was measured with positron emission tomography (nine-segment model) at rest, during maximal coronary hyperemia with adenosine, and during increased myocardial work with dobutamine. Abnormal flow was defined as myocardial blood flow <75% of maximum perfusion during adenosine plus placebo (46 normal/17 abnormal segments dentified). RESULTS: Compared with placebo, tadalafil had no significant effect on global myocardial blood flow at rest, during adenosine infusion, or during dobutamine infusion. Similarly, in normal and abnormal segments, tadalafil versus placebo had no significant effect on resting myocardial blood flow or on adenosine-induced increases in myocardial blood flow. In normal segments, myocardial blood flow with dobutamine plus tadalafil was greater than that with dobutamine plus placebo (1.79+/-0.56 versus 1.56+/-0.37 ml/g per min, P<0.01), and in abnormal segments, there was a trend for tadalafil compared with placebo to increase myocardial blood flow during dobutamine infusion (1.46+/-0.44 versus 1.36+/-0.36 ml/g per min, P=0.7). CONCLUSIONS: Tadalafil had no significant effect on global myocardial blood flow at rest, during adenosine infusion, or during dobutamine infusion. Compared with placebo, tadalafil significantly augmented myocardial blood flow during increased workload in normal regions, with a trend toward improving myocardial blood flow in poorly perfused regions.     

Effect of azithromycin therapy on coronary circulation in patients with coronary artery disease

This study examined the effect of azithromycin therapy on the coronary microcirculation using measurement of coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography in 35 patients with coronary artery disease. CFVR increased significantly after azithromycin therapy (3.0 +/- 0.7 vs 3.5 +/- 0.7, p <0.001). The changes in CFVR were negatively correlated with changes in high-sensitivity C-reactive protein levels in patients receiving azithromycin.     

Effect of carbocromen induced coronary vasodilatation on myocardial metabolism in coronary artery disease

Myocardial metabolism was studied during coronary vasodilatation by carbocromen during atrial pacing in patients with coronary arteriosclerotic disease. Coronary sinus flow was measured by the continuous infusion thermodilution technique. Carbocromen increased myocardial flow by the same amount at rest and during pacing-induced tachycardia. The administration of carbocromen did not interfere with myocardial oxygen consumption, free fatty acid (FFA) uptake, pulmonary or systemic hemodynamics. Atrial pacing above the anginal threshold increased lactate and hypoxanthine excretion to the coronary sinus, but to a greater extent during carbocromen treatment. Thus, carbocromen is a specific coronary vasodilator acting independently of pacing induced vasodilatation. Metabolic data indicate a small but unfavourable effect on ischemic metabolism which might be due to a “coronary steal”.     

Effect of intravenous testosterone on myocardial ischemia in men with coronary artery disease

Background Studies on the effect of estrogen on atherosclerotic coronary artery disease (CAD) risk in women have produced conflicting results. Similar confusion, but fewer data, exists on the effect of testosterone on CAD risk in men. Methods We used ^99mTc sestamibi single-photon emission computed tomography (SPECT) myocardial perfusion imaging to examine the acute effect of intravenous testosterone in 32 men (mean age, 69.1 ± 6.4 years) with provocable myocardial ischemia on standard medical therapy. Patients performed 3 exercise (n = 18) or adenosine (n = 16) stress tests during the infusion of placebo or 2 doses of testosterone designed to increase testosterone 2 or 6 times baseline. Results Serum testosterone increased 137 ± 58% and 488 ± 113%, and estradiol levels increased 27 ± 46% and 76 ± 57%, (P < .001 for all) during the 2 testosterone infusions. There were no differences among the placebo or testosterone groups in peak heart rate, systolic blood pressure, maximal rate pressure product, perfusion imaging scores, or the onset of ST-segment depression. Conclusions Acute testosterone infusion has neither a beneficial nor a deleterious effect on the onset and magnitude of stress-induced myocardial ischemia in men with stable CAD. (Am Heart J 2002;143:249-56.)