Orhan Onalan

Evaluation of Endothelial Dysfunction: Flow-Mediated Dilation

By the time the clinical findings of atherosclerotic disease appear, involvement is usually at an advanced stage and procedures after this stage are usually palliative or aimed at secondary protection. On the other hand, prevention can be achieved by the detection and treatment of endothelial dysfunction, which is one of the most important changes in the early subclinical stage of atherosclerotic disease. When the systemic involvement of endothelial dysfunction is taken into consideration, checking from the peripheral arteries with noninvasive methods gives one-to-one correct information. Currently, endothelial dysfunction can be detected using simple, inexpensive, and noninterventional methods. Particularly, easily accessible localization of the brachial artery is ideal for the evaluation of endothelial dysfunction. Flow-mediated dilation method (FMD; endothelial-dependent vasodilation), which can be carried out noninvasively with ultrasonography on the brachial artery, is a frequently used method for the assessment of endothelial dysfunction. A sphygmomanometer is placed on the forearm to create a flow stimulation in the brachial artery. The sphygmomanometer is inflated until the systolic pressure is above 50 mm Hg, thus stopping the antegrade blood flow and creating ischemia. Consequently, vasodilation occurs at the resistance arteries distal to where the flow is blocked. When the sphygmomanometer is deflated, a reactive hyperemia occurs in the brachial artery. The % difference between the diameter measured after reactive hyperemia and the basal diameter is taken as FMD. The effects of the treatments on endothelial dysfunction can be monitored with this method. Studies have shown that angiotensin-converting enzyme (ACE) inhibitors, angiotensin 1 (AT1) receptor blockers, latest-generation beta blockers such as nebivolol and carvediol, statins, estrogen treatment, diet, and exercise increase FMD. Before this method becomes a part of routine clinical evaluation of cardiovascular disease (CVD) risk, measurement technique and FMD values need to be standardized.

Early Effects of Treatment with Nebivolol and Quinapril on Endothelial Function in Patients with Hypertension

The objective of the present study was to compare the early effects of treatment with nebivolol and quinapril on the endothelial function in hypertensive patients. A total of 54 hypertensive patients was enrolled in the present study. One of the groups (n = 27) received quinapril 20 mg/day, and the other group (n = 27) received nebivolol 5 mg/day for a period of 4 weeks. The endothelial dysfunction was assessed using FMD (flow-mediated vasodilation) of the brachial arteries. The baseline characteristics of both groups were similar in age, gender, left venticular ejection fraction, left ventricular mass index, and body mass index. No significant difference was also found between the groups in the distribution of atherosclerotic risk factors as well as other echocardiographic, demographic, and biochemical measurements. Although the reduction of diastolic blood pressure was more pronounced in the nebivolol group after a 4-week treatment, the change in the systolic blood pressure was found to be similar in both treatment arms. Although a statistically nonsignificant increase was observed in flow-mediated vasodilation in the quinapril group (4.77% +/- 3.92%, 5.60% +/- 6.18%; p = .587), the increase in the post-treatment FMD was statistically significant in the nebivolol group (3.78% +/- 4.25%, 8.56% +/- 6.39%; p = .002). A significant change was observed in the resistive index value following flow-mediated vasodilation for both groups after treatment (p = .043; p = .027), whereas the change in the value of flow volume was significant only in the nebivolol group (p = .019).

Relation between fragmented QRS and collateral circulation in patients with chronic total occlusion without prior myocardial infarction.

OBJECTIVE It has been shown that the fragmented QRS (fQRS) on electrocardiogram (ECG) signifies regional myocardial scar in patients with non-Q-wave myocardial infarction (MI). We hypothesized that presence of fQRS on ECG may be related with poorly-grown collateral coronary circulation (CCC) in patients with chronic total coronary occlusion (CTO) without prior MI. METHODS This retrospective observational study is included 56 patients (mean age 61.73±7.96 years; 67.9% men) with CTO in one of the major coronary arteries. Collateral circulation was graded according to Rentrops classification. The fQRS was defined as the presence of an additional R wave or notching of R or S wave or the presence of fragmentation in two contiguous ECG leads corresponding to a major coronary artery territory. Patients with pathological Q-wave or history of MI, typical bundle brunch blocks (BBB) and incomplete right BBB were excluded from study. Statistical analysis was performed using Chi-square test, Students t-test and logistic regression analysis. RESULTS Fifteen patients had Rentrop grade 1, 15 patients had grade 2 and 26 patients had grade 3 CCC. Five (19%) of the patients who have grade 3 CCC, seven (47%) of the patients who had grade 2 CCC, ten (67%) of the patients who had grade 1 CCC had fQRS (p=0.002). Logistic regression analysis showed high predictive value of the presence of fQRS for Rentrop 1 CCC (OR=8.4, 95% CI 1.97-35.7; p=0.004). CONCLUSION Results of our study may implicate the presence of fQRS on electrocardiogram as a predictor of a poorly grown CCC in patients with chronic total occlusion without prior MI.

Mildly Decreased Glomerular Filtration Rate Is Associated With Poor Coronary Collateral Circulation in Patients With Coronary Artery Disease

The aim of this study was to evaluate the association between mildly decreased glomerular filtration rate (GFR) and coronary collateral circulation (CCC).

Relationship between red cell distribution width and echocardiographic parameters in patients with diastolic heart failure

Red cell distribution width (RDW) was found to be a prognostic marker in heart failure patients. The aim of the study was to investigate the relationship between RDW and echocardiographic parameters in diastolic heart failure (DHF). Seventy‐one consecutive DHF patients (26 men) and 50 controls (21 men) were included in the study. All of the study population underwent echocardiographic evaluation, and blood samples were obtained. RDW and N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) values were significantly higher, whereas there was an increasing trend for high‐sensitivity C‐reactive protein levels in DHF patients than those in controls (p < 0.001, p < 0.001, and p = 0.064, respectively). All of the echocardiographic parameters evaluating diastolic function were more deteriorated in the DHF group. Patients who had an RDW value greater than the cutoff point also had higher NT‐proBNP levels, an elevated ratio of mitral peak velocity of early diastolic filling to early diastolic mitral annular velocity, and increased estimated pulmonary capillary wedge pressures by tissue Doppler parameters, but lower creatinine clearance (p < 0.05 for all). According to the cutoff values calculated using receiver operating characteristic analysis, RDW > 13.6% and NT‐proBNP > 125 pg/mL have high diagnostic accuracy for predicting DHF. RDW values were increased in the DHF population. Our results suggest that the high RDW levels in patients with DHF may be related to increased neurohormonal activity, impaired renal functions, and elevated filling pressure, but not to increased inflammation.

Antioxidant status and levels of antioxidant vitamins in coronary artery ectasia.

BackgroundCoronary artery ectasia (CAE) is a rare coronary artery anomaly. In this study, we investigated superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and &ggr;-glutamyltransferase (GGT) activities, and antioxidant vitamin levels (vitamins A and E) in patients with CAE. MethodsForty-five patients who were diagnosed with CAE using coronary angiography were included in the study (26 men; mean age, 57±9 years). The control group consisted of 35 participants who had normal coronary arteries as shown by coronary angiography (14 men; mean age, 54±7 years). The plasma activity of SOD, GSH-Px, GGT, and levels of vitamins A and E were measured. ResultsThe plasma SOD activity was significantly lower in the CAE group compared with the control group (0.70±0.64 vs. 1.52±0.85 U/ml; P=0.001). The serum GGT activity was higher in the CAE group compared with the control group (34±20 vs. 26±13 U/ml; P=0.04). There were no significant differences in the plasma GSH-Px activity and vitamin A and E levels. There was a positive correlation between SOD activity and low-density lipoprotein cholesterol levels (r=0.418; P=0.01). There was also a positive correlation between vitamin E and low-density lipoprotein cholesterol (r=0.410; P=0.01) and triglyceride levels (r=0.310; P=0.04) in patients with CAE. ConclusionIn this study, patients with CAE had a decreased SOD plasma activity and an increased GGT activity compared with normal controls. These results suggest that oxidative stress and antioxidant status may have an important role in the pathogenesis of CAE.

Empiric slow pathway ablation in non-inducible supraventricular tachycardia

BACKGROUND The data supporting the practice of empiric slow pathway ablation (ESPA) in patients with documented supraventricular tachycardia (SVT) who are non-inducible at electrophysiology study (EPS) is limited. The aim of this study is to assess the efficacy of ESPA in adults. METHODS A multi-center cohort study of patients who had ESPA between January 2008 and October 2013 was performed. Patients were identified by screening sequential SVT ablation procedures. RESULTS Forty-three (5%) out of 859 SVT ablation procedures were identified as ESPA. The median age was 53 (IQR: 24) years; 63% were female. All patients had pre-EPS documentation of SVT (either strip or ECG). In 23 (53.5%) cases, pre-EPS ECG showed short RP tachycardia. Thirty-two (74.4%) patients had dual atrioventricular nodal physiology (DAVNP) plus echo beats. Junctional rhythm (JR) as procedural endpoint was noted in 39 (90.7%) patients. In 18 (41.9%) patients, the abolishment of DAVNP was achieved. No complications were encountered. A median follow-up of 17 months (range: 6 to 31 months) revealed 83.7% (36 of 43) success rate, defined as the absence of pre-procedural symptoms and any documented sustained arrhythmia. As compared to patients with recurrence (n=7), patients with no recurrence (n=36) had significantly higher prevalence of clinical short RP tachycardia (61.1% vs. 14.3%, p=0.038), and EPS finding of DAVNP plus echo beats (80.6% vs. 42.9%, p=0.034). CONCLUSIONS ESPA is a reasonable approach in patients with documented SVT, in particular in short RP tachycardia, who are not inducible at EPS. Larger studies are required to assess this practice.

The Effect of Slow Coronary Flow on Right and Left Ventricular Performance

Objective: To evaluate left and right ventricular functions using tissue Doppler echocardiography (TDE) and myocardial performance index (MPI) methods in patients with slow coronary flow (SCF) and to determine the relationship between these parameters and thrombolysis in myocardial infarction frame count in SCF patients. Subjects and Methods: Thirty-five patients (20 males and 15 females) with SCF who underwent coronary angiography and 35 age- and sex-matched controls (14 males and 21 females) without SCF who underwent elective coronary angiography were enrolled in the study. Left ventricular (LV) and right ventricular (RV) functions were examined using conventional echocardiography and TDE. Results: LV systolic myocardial velocity (Sm), early myocardial velocity (Em), late myocardial velocity (Am), and Em/Am ratio were similar in both the SCF and control groups; however, isovolumetric relaxation time (IRT) was higher in the SCF group compared to the control group (IRT: 99 ± 17 vs. 88 ± 20; p = 0.01). In patients with SCF, LV MPI was higher than in the control group, but this was not statistically significant (0.61 ± 0.11 vs. 0.56 ± 0.12; p = 0.07). The RV tricuspid annular velocities and MPI were similar in the SCF and control groups. Conclusion: This study showed that SCF affected LV functions echocardiographically and could cause partially reduced LV performance. In addition, SCF did not affect RV functions echocardiographically.

The protective effect of single dose tadalafil in contrast-induced nephropathy: an experimental study.

Objective: Contrast-induced nephropathy (CIN) is one of the most common causes of acute renal failure in hospitalized patients. The direct toxic effect of contrast media; ischemic damage caused by reactive oxygen species; increased perivascular hydrostatic pressure; high viscosity and changes in the activity of vasoactive substances play important roles in the pathogenesis. Tadalafil inhibits the phosphodiesterase enzyme which destroys nitric oxide. Nitric oxide causes renal vasodilatation, increases renal medullar blood flow and mediates the removal of free oxygen radicals. Drugs that increase levels of nitric oxide are expected to reduce the development of contrast nephropathy due to contrast media. We aimed to test the hypothesis that tadalafil reduces the development of contrast nephropathy due to contrast toxicity. Methods: A total of 24 female Wistar albino rats, three groups of eight, were included in the study. After 48 hours of dehydration, contrast media (meglumine diatrozoate, 6 mL/kg) was administered to the first group, and contrast media with tadalafil (10 mg/kg) was administered to the second group. The third group served as the control group. Blood and tissue samples were taken 48 hours after this procedure. Results: Serum cystatin C, serum creatinine and blood urea nitrogen (BUN) values were significantly lower in the contrast with tadalafil group compared to the group given only contrast. Serum and tissue malondialdehyde (MDA) levels were significantly lower in the contrast with tadalafil group than in the contrast only group. Conclusion: These results demonstrate the protective effect of tadalafil in the prevention of CIN in rats.

Effects of prediabetes on coronary collateral circulation in patients with coronary artery disease.

BackgroundThe risk for cardiovascular disease almost increases in patients with impaired glucose tolerance compared with those with normal glucose tolerance. In experimental studies, it has been shown that impaired fasting glucose has negative effect of coronary collateral circulation (CCC). The aim of this study is to investigate the effects of prediabetes on coronary collateral development in patients with coronary artery disease. MethodsWe retrospectively enrolled 230 patients who underwent coronary angiography. All study participants had at least one occluded major coronary artery. Prediabetes was defined according to the American Diabetes Association definition and patients were then classified into having prediabetes group and control group. To classify CCC we used Rentrops scoring system. Rentrop grades of 0 and 1 indicate poor CCC whereas 2 and 3 indicate good CCC. Groups were compared using the &khgr;2, the Student t or the Mann–Whitney U-tests. To identify predictors of CCC, multivariable logistics regression analysis was performed. ResultsThe prediabetes group consisted of 104 patients and the control group consisted of 126 patients. Both groups were comparable for basal characteristics. Poor CCC was higher in the patients with prediabetes (P<0.001). Multivariable logistic regression analysis showed that fasting glucose level was the only independent predictor of CCC (B=−0.124; odds ratio=0.883; 95% confidence interval=0.85–0.92; P<0.001). ConclusionOur study showed that coronary collateral development was impaired in patients with prediabetes when compared with patients with coronary artery disease who had normal fasting glucose level.