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Development of coronary collaterals (CCs) is triggered by the gradient between arteries due to obstruction and myocardial ischemia. Presence of CCs that feed the jeopardized myocardial area may limit the infarct size after coronary occlusion and may even provide a survival benefit. However, some patients develop good CCs, whereas others do not. The metabolic syndrome (MS) has been identified as a secondary target to decrease cardiovascular risk, although the effect of MS on development of CCs has not been investigated. We prospectively enrolled 596 consecutive patients (337 men and 259 women; mean age 56 +/- 8 years) who underwent coronary angiography at our center and were found to have total occlusion of the right coronary artery. Patients were then classified as having good CCs (Rentrop's grades 2 to 3) or poor CCs (Rentrop's grades 0 to 1). There were significant differences in terms of body mass index (kilograms of body weight divided by square meters of height), glucose levels, triglyceride levels, and years with angina pectoris between those with good and poor CCs. Prevalences of diabetes mellitus were 27.1% among patients with good CCs and 44% among those with poor CCs (p <0.001). Presence of MS was significantly higher in patients with poor CCs than in those with good CCs (78.4% vs 49.2%, p <0.001). In regression analysis, duration of angina pectoris (beta = 0.347, 95% confidence interval [CI] 0.266 to 0.453, p <0.001), presence of diabetes mellitus (beta = 1.829, 95% CI 1.021 to 3.279, p = 0.042), wall score (beta = 2.379, 95% CI 1.356 to 4.173, p = 0.003), and presence of MS (beta = 2.993, 95% CI 1.541 to 5.813, p = 0.001) were independent predictors of angiographically determined poor CCs. In conclusion, MS seems to be independently associated with poor CCs in patients with an occluded right coronary artery.

Objective: Muscle fibers overlying the intramyocardial segment of an epicardial coronary artery are termed myocardial bridging. Variable prevalence has been described at autopsy and angiographic series with small and large sample sizes. The aim of the study was to investigate the angiographic prevalence of myocardial bridging in 25982 patients from Turkey., Methods: We performed a retrospective study, evaluated the cases with myocardial bridging among patients undergone selective coronary angiography, and searched the angiographic prevalence of myocardial bridging in a very large sample size. We studied also the correlation between the severity of the bridging and risk factors for coronary artery disease., Results: Among 25982 patients we found 316 cases of myocardial bridging in a retrospective manner. The total prevalence was 1.22%. Although, 96.52% of patients with myocardial bridging had the lesion in the left anterior descending coronary artery (LAD) as expected, distribution of bridges between mid- and distal segments were almost equal (52.79% and 47.21%, respectively). We subclassified patients in two groups, Group A (<50% of systolic compression) and Group B (>or=50% of systolic compression), according to the amount of systolic compression of LAD and studied relationship of risk factors for coronary artery disease between groups. Another subclassification was also made for patients having myocardial bridging without coronary or valvular heart disease and hypertrophic obstructive cardiomyopathy; Group 1 (<50% of systolic compression) and Group 2 (>or=50% of systolic compression). In these patients we studied correlation between the severity of the myocardial bridging and risk factors for coronary artery disease. The prevalence of bridges in circumflex and right coronary arteries individually and in all arteries as combination was also studied., Conclusion: In a very large group of patients from Turkey undergone selective coronary artery angiography, the angiographic prevalence of myocardial bridging was slightly higher than expected. Only diabetes mellitus as a risk factor for coronary artery disease was higher in groups representing <50% of systolic compression (Group A and 1) than in groups representing >or=50% of systolic compression (Group B and 2) but the importance of this result is not known.

Dobutamine stress echocardiography, Tc-99m radionuclide ventriculography (RNVG), and exercise stress testing were performed prospectively in 63 patients with suspected coronary artery disease to compare the values of exercise testing, dobutamine stress echocardiography and RNVG in the non-invasive diagnosis of coronary artery disease. The sensitivities of dobutamine stress echocardiography and RNVG were found to be higher than that of exercise testing (93-62%, p < 0.001; 83-62%, p < 0.05). The sensitivities of dobutamine stress echocardiography and RNVG were similar (p > 0.05). There were no differences between the sensitivities of the three techniques in multiple vessel disease (p > 0.05). The specificities of dobutamine stress echocardiography and RNVG were higher than that of exercise testing (for both of the tests 86-62%, p < 0.05). The diagnostic accuracy of dobutamine stress echocardiography and RNVG were similar (p > 0.05). The results of dobutamine stress echocardiography RNVG were concordant with each other in 46 patients (76%, kappa = 65%) in sectional analysis. Dobutamine stress echocardiography and RNVG tests were comparable with each other in 85% of the 189 segments (kappa = 64%). The expected 5% decrease at peak doses of dobutamine was not detected in stress echocardiography in 25 patients and in RNVG in 26 of the patients. Dobutamine stress echocardiography and RNVG are superior to exercise testing in the diagnosis of single vessel disease and there is no significant difference between the two techniques. When the ejection fraction is considered in dobutamine stress echocardiography and RNVG, it does not make an additional contribution to the diagnosis of coronary artery disease.

To compare the value of exercise electrocardiography with dobutamine stress echocardiography and exercise technetium-99m isonitrile single-photon emission computed tomography for coronary artery disease, 70 patients with either suspected or proven coronary artery disease underwent dobutamine stress echocardiography, exercise technetium-99m isonitrile single-photon emission computed tomography (mibi-SPECT) and treadmill exercise electrocardiography (ECG). Dobutamine echocardiography and exercise mibi-SPECT revealed a higher overall sensitivity than exercise testing (90 vs 57%, p < 0.001; 96 vs 57%, p < 0.001, respectively). Dobutamine stress echocardiography showed a higher specificity than both exercise mibi-SPECT and treadmill exercise electrocardiography (90 vs 71%, p > 0.05; 90 and 62% p < 0.05, respectively) but the difference between dobutamine stress echocardiography and exercise mibi-SPECT was not statistically significant. Diagnostic accuracy of dobutamine stress echocardiography and exercise mibi-SPECT was higher than that of exercise testing (90 vs 59%, p < 0.001; 89 vs 59%, p < 0.001, respectively). Dobutamine stress echocardiography and exercise mibi-SPECT have superiority over exercise testing in the diagnosis of coronary artery disease and dobutamine stress echocardiography is an alternative for exercise mibi-SPECT.

The object of our study was to compare the value of exercise stress testing with simultaneous dobutamine stress echocardiography and technetium-99m isonitrile single-photon emission computed tomography for the diagnosis of coronary artery disease. Sixty-nine patients with either suspected or proven coronary artery disease underwent simultaneous dobutamine technetium-99m isonitrile single-photon emission computed tomography and stress echocardiography, and treadmill exercise electrocardiography. Dobutamine echocardiography and technetium-99m isonitrile single-photon emission computed tomography revealed a higher overall sensitivity than exercise testing (94 vs 60%, P < 0.001), but dobutamine stress echocardiography showed a higher specificity than both technetium-99m isonitrile single-photon emission computed tomography and exercise testing (86 vs 64%, P < 0.05, for both tests). In addition, the diagnostic accuracy of dobutamine stress echocardiography and technetium-99m isonitrile single-photon emission computed tomography was higher than that of exercise testing (91 vs 61%, P < 0.001; 86 vs 61%, P < 0.001, respectively). Dobutamine stress echocardiography and technetium-99m isonitrile single-photon emission computed tomography are superior to exercise testing in the diagnosis of coronary artery disease, and dobutamine stress echocardiography can act as an alternative to technetium-99m isonitrile single-photon emission computed tomography.