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Biomedical subjects

Aylin Yildirir

Publications and source records attributed to Aylin Yildirir.

At least 19 recordsLinked to original sources
PubMed2006

Coronary flow reserve is impaired in patients with slow coronary flow.

BACKGROUND: Slow coronary flow (SCF) in a normal coronary angiogram is a well-recognized clinical entity, but its etiopathogenesis remains unclear. However, previous studies have suggested that microvascular abnormalities and endothelial dysfunction responsible for SCF. Accordingly, we hypothesized that SCF phenomenon may be a form, at least early phase, of atherosclerosis that involve both small vessels and epicardial coronary arteries, and therefore we investigated coronary flow reserve (CFR) reflecting coronary microvascular function in patients with SCF. METHODS: Twenty subjects with SCF and 15 control subjects with normal coronary flow were studied. Coronary flow was quantified according to TIMI frame count (TFC). Coronary diastolic peak flow velocities were measured at baseline and after dipyridamole infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocities. RESULTS: Demographic features, coronary risk factors, echocardiographic measurements except diastolic function parameters, and biochemical measurements were similar between the groups. CFR values were significantly lower in subjects with SCF than in the control group (1.99+/-0.38 versus 2.99+/-0.47, P<0.0001). In addition, TIMI frame count independently correlated with CFR. CONCLUSION: These findings suggest that CFR, which reflects coronary microvascular function, is impaired in patients with SCF, and corrected TFC well correlates with CFR.

Adult↗
PubMed2006

Effects of metoprolol therapy on cardiac troponin-I levels after elective percutaneous coronary interventions.

AIMS: Beta-blockers (BBs) have been shown to improve survival and reduce the risk of re-infarction in patients following myocardial infarction. There are conflicting data about the effects of BB therapy on cardiac biomarkers after percutaneous coronary interventions (PCIs). The aim of the study was to investigate the effects of BB use on cardiac troponin-I (cTnI) levels in patients who had undergone elective PCI. METHODS AND RESULTS: In this prospective study, 287 patients with coronary artery disease were included. Patients were randomized either to BB or control groups prior to the intervention. Blood samples for cTnI were obtained before and at 6, 24, and 36 h after the procedure. Of the 287 patients included, 143 received metoprolol succinate 100 mg/day, and 144 received no BB and served as the control group. Baseline clinical characteristics of both groups, except for history of coronary artery bypass graft surgery, were similar. We observed no significant difference in the elevation of cTnI levels between the two groups after PCI (BB group, 17 patients, 11.9%; control group, 10 patients, 6.9%; P=0.2). CONCLUSION: Metoprolol succinate therapy seems to have no cardioprotective effect in limiting troponin-I rise after PCI.

Administration, Oral↗
PubMed2006

Frequency of atrial fibrillation and factors related to its development in dialysis patients.

BACKGROUND: The frequency of atrial fibrillation is increased in patients with end-stage renal disease. In this study, we sought to determine the incidence of persistent and paroxysmal atrial fibrillation in patients with end-stage renal disease and to identify the risk factors associated with this arrhythmia. METHODS: Two hundred seventy-five patients with end-stage renal disease who were in a hemodialysis program for at least 4 months were included in the study. Patients with permanent, persistent, or paroxysmal atrial fibrillation were identified and recorded. All patients were evaluated for cardiac risk factors and arrhythmias. RESULTS: Thirty (10.9%) of the 275 patients were found to have atrial fibrillation. Ten (33.3%) of these patients had permanent or persistent atrial fibrillation, and 20 (66.6%) of these patients had paroxysmal atrial fibrillation. Patients with atrial fibrillation were older. Incidences of hypertension, coronary artery disease, left ventricular systolic dysfunction, right atrial diameters, and mitral and/or aortic calcification were significantly higher in patients with atrial fibrillation. Serum albumin and high-density lipoprotein levels were significantly lower in patients with atrial fibrillation. CONCLUSIONS: Our data indicate that atrial fibrillation is a frequent arrhythmia in patients with end-stage renal disease, and the most frequently encountered form is paroxysmal atrial fibrillation. In this patient group, presence of coronary artery disease, age, and right atrial diameter are independent factors for determination of the risk of development of atrial fibrillation.

Aged↗
PubMed2006

Rhesus positivity and low high-density lipoprotein cholesterol: a new link?

The aim of the study was to investigate the relationship of ABO and Rh blood groups with lipid profile in patients with established multivessel coronary artery disease in a population with low levels of high-density lipoprotein cholesterol. The records of 978 patients with multivessel coronary artery disease, in whom coronary bypass surgery was performed, were investigated. Coronary risk factors including diabetes, hypertension, smoking, and obesity were noted for each patient. Serum lipid profiles: total cholesterol, low-density and high-density lipoprotein cholesterol, and triglyceride levels, were also recorded. The mean age of the patients was 59.3 +/- 9.7 years (range, 25-84 years) and 80% were male. The risk factors and lipid profiles of ABO blood types were similar. Rh-negative patients had higher levels of high-density lipoprotein cholesterol (46.9 +/- 9.9 vs. 41.6 +/- 10.4 mg.dL(-1), p = 0.001) and a lower total/high-density lipoprotein cholesterol ratio (4.8 +/- 1.3 vs. 5.2 +/- 1.6, p = 0.029) compared to Rh-positive patients. The other lipid levels and risk factors had no association with Rh typing. These results indicate a significant association between rhesus positivity and low levels of high-density lipoprotein cholesterol in patients with multivessel coronary artery disease.

ABO Blood-Group System↗
PubMed2006

Cardiac enzymes, renal failure and renal transplantation.

Diagnostic accuracy of the currently available serum markers of cardiac injury, such as myoglobin, creatine kinase and its myocardial isoform, are altered in patients with renal failure. It is shown that cardiac troponins have decreased diagnostic sensitivity and specificity in patients receiving renal replacement therapy. Data regarding serum levels of these cardiac biomarkers, especially those of the cardiac troponins, in patients with a transplanted kidney are limited. Current data show that levels of cardiac troponin I are unaltered in patients who have undergone renal transplantation, while levels of cardiac troponin T may be elevated.We believe that cardiac troponin I should be the biomarker of choice for diagnosis of myocardial injury in these patients. However, further trials are required for conclusive results.

Biomarkers↗
PubMed2005

Do young women with polycystic ovary syndrome show early evidence of preclinical coronary artery disease?

BACKGROUND: It is thought that women with polycystic ovary syndrome (PCOS) are at increased risk of developing cardiovascular diseases. METHODS: In this study, we used transthoracic echocardiography to measure coronary flow reserve (CFR) in 28 women with PCOS and in 26 healthy women. RESULTS: The PCOS and the control groups were similar in terms of age (27.1 +/- 4.5 versus 28.8 +/- 4.4 years) and BMI (26.6 +/- 5.7 versus 24.7 +/- 4.4 kg/m2). Fasting insulin levels and homeostasis model assessment insulin resistance index were higher in the PCOS group. LH, the LH/FSH ratio, total testosterone, free testosterone and androstenedione were higher in the PCOS group. FSH, estradiol, prolactin, progesterone, cholesterol, triglyceride and high-sensitive C-reactive protein were similar between the two groups, but homocysteine levels were higher in the PCOS group. Baseline diastolic peak f low velocity (DPFV) (25.0 +/- 4.6 versus 23.3 +/- 2.7 cm/s, P > 0.05), hyperaemic DPFV (71.2 +/- 12.8 versus 73.0 +/- 12.9 cm/s, P > 0.05) and CFR (2.8 +/- 0.8 versus 3.2 +/- 0.8 cm/s, P > 0.05) of the left anterior descending coronary artery were similar between the two groups. CONCLUSION: We conclude that in young women with PCOS and without cardiovascular risk factors, CFR is preserved.

Adult↗
PubMed2005

Beta blocker effects on plasma homocysteine levels in patients with hypertension.

Recent studies have shown that hyperhomocysteinemia might play a role in the pathogenesis of hypertension. The effects of antihypertensive agents on plasma homocysteine levels have not been tested extensively. We investigated the effects of beta-blocker therapy on homocysteine levels in patients with hypertension. In the study, 120 patients with newly diagnosed hypertension were enrolled. All patients received metoprolol succinate 100 mg/day initially. If blood pressure was above normal on the 15th day of follow-up, the metoprolol dosage was doubled. Before initiation of the antihypertensive medication and after the fourth month of treatment, homocysteine levels were measured. Of the 120 patients enrolled, 39 could not complete the study. Homocysteine levels decreased significantly by the end of the fourth month when compared with basal values (13.5+/-4.5 micromol/l versus 12.4+/-4.9 micromol/l; P = 0.001). There was no relation between homocysteine level and blood pressure control. There was a significant decrease in homocysteine levels in the women treated in this study (P = 0.001); however, this effect was absent in men (P = 0.185). We demonstrate that metoprolol succinate treatment significantly decreases plasma homocysteine levels in patients with hypertension, especially in women.

Adrenergic beta-Antagonists↗
PubMed2005

The effects of prior beta-blocker therapy on serum C-reactive protein levels after percutaneous coronary intervention.

BACKGROUND: There are no studies in the literature related to the effect of beta blockers (BB) on changes in C-reactive protein (CRP) levels after percutaneous coronary intervention (PCI). HYPOTHESIS: We designed a prospective randomized study to investigate the impact of BB therapy on CRP in patients who underwent elective PCI. METHODS: In all, 300 patients with coronary artery disease were included. Patients were randomized to either a metoprolol or to a control group before PCI. Blood samples for CRP levels were obtained before BB treatment, and at the 6th, 24th, and 36th h after PCI. RESULTS: Of 300 patients, 150 received metoprolol 100 mg/day (mean age, 59.0 +/- 10.2 years; 106 men, 44 women), and 150 received no BB (mean age, 59.8 +/- 9.8 years; 114 men, 36 women) and served as the control group. Baseline clinical characteristics of both groups were similar. Basal CRP levels between the two groups were similar. Of the patients included in the study, 40.8% in the BB group and 39.6% in the control group had elevated basal CRP levels. The CRP levels increased above baseline values in 85% of patients in the BB group and in 89.3% of patients in the control group (p > 0.05) during follow-up. The CRP levels in patients in the BB group at the 6th, 24th, and 36th h were lower than those in the control group; however, this difference did not reach statistical significance. CONCLUSIONS: Prior BB therapy seems to have no effect on CRP levels after PCI.

Adrenergic beta-Antagonists↗
PubMed2005

Effectiveness of triple-site triggered atrial pacing for prevention of atrial fibrillation after coronary artery bypass graft surgery.

BACKGROUND: Recently, several temporary multisite pacing methods have been developed for prevention of postoperative atrial fibrillation (AF). HYPOTHESIS: In this study, we evaluated the effect of triple-site temporary triggered pacing in the AAT mode on the development of AF in patients undergoing coronary artery bypass graft (CABG) at high risk for developing postoperative AF. METHODS: A total of 70 patients undergoing CABG were randomly assigned either to pacing group (study group, n = 35 patients) or to no pacing group (control group, n = 35 patients). The external pacemaker was programmed to pace at the atrial triggered mode at a lower rate of 40 beats/min for 4 days. RESULTS: Atrial fibrillation, defined as lasting > 30 s, occurred in 4 patients (11.4%) in the study group and in 16 patients (45.7%) in the control group (p = 0.003). Sustained AF, defined as AF lasting > 10 min, also was observed less frequently in the study group than in the control group (11.6 vs. 37.1%, p = 0.024). Triple-site triggered atrial pacing was observed to reduce the incidence of AF by 75% and the incidence of sustained AF by 69%. CONCLUSIONS: We believe that multiple-site temporary pacing in the triggered mode is an effective way of preventing postoperative AF. This technique may be used especially in patients at high risk of developing AF.

Aged↗
PubMed2005

Typical ECG changes unmasked by ajmaline in a patient with Brugada syndrome and left bundle branch block.

Brugada syndrome is a channelopathy associated with right bundle branch block and ST segment elevation in the right precordial leads. These electrocardiographic signs may not be apparent most of the time but can be unmasked by certain antiarrhythmic agents. Until now, all of the reports on this syndrome have focused on patients with no significant intraventricular conduction delay at baseline electrograms. In this report, we describe a patient with Brugada syndrome with left bundle branch block at baseline ECG. After intravenous ajmaline, the patient developed right bundle branch block and ST segment elevations in the right precordial leads.

Adult↗
PubMed2005

Melatonin levels decrease in type 2 diabetic patients with cardiac autonomic neuropathy.

The present study has been designed to determine melatonin levels in type 2 diabetic patients and test the relationship between the autonomic nervous system and melatonin dynamics. Thirty-six type 2 diabetic patients and 13 age-matched healthy subjects were recruited for the study. Circadian rhythm of melatonin secretion was assessed by measuring serum melatonin concentrations between 02:00-04:00 and 16:00-18:00 hr. Melatonin dynamics were re-evaluated with respect to autonomic nervous system in diabetic patients with autonomic neuropathy who were diagnosed by the cardiovascular reflex tests, heart rate variability (HRV), and 24-hr blood pressure monitoring. Nocturnal melatonin levels and the nocturnal melatonin surge were low in the diabetic group (P = 0.027 and 0.008 respectively). Patients with autonomic neuropathy revealed decreased melatonin levels both at night and during day when compared with healthy controls (P < 0.001 and 0.004 respectively) while the melatonin dynamics were similar to controls in patients without autonomic neuropathy. Nocturnal melatonin level was positively correlated with nocturnal high and low frequency components of HRV (P = 0.005 and 0.011 respectively) and systolic and diastolic blood pressures at night (P = 0.002 and 0.004 respectively) in patients with autonomic neuropathy. We found a negative correlation between nocturnal melatonin levels and the degree of systolic blood pressure decrease at night (r = -0.478, P = 0.045). As a conclusion this study has shown that circadian rhythm of melatonin secretion is blunted in type 2 diabetic patients and there is a complex relationship between various components of autonomic nervous system and melatonin secretion at night. Among the patients with autonomic neuropathy those with more preserved HRV and the systolic nondippers (<10% reduction in blood pressure during the night relative to daytime values) have more pronounced melatonin surge at night.

Autonomic Nervous System Diseases↗
PubMed2005

Statin therapy helps to control blood pressure levels in hypertensive dyslipidemic patients.

AIM: Aside from lowering lipid levels; statins improve endothelial function, decrease platelet aggregation, reduce procoagulant blood factors, and decrease vascular tone. This study was conducted to investigate the possible effect of atorvastatin on blood pressure (BP) in a group of hypertensive and dyslipidemic patients. METHODS: Thirty-six hypertensive and dyslipidemic patients with inadequately controlled lipid levels by diet were treated with atorvastatin 20 mg/day for 8 weeks and compared with 24-patient matched controls treated with diet alone. The type and dosage of antihypertensive medications were not altered during statin therapy. Blood lipid profile including total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglyceride (TG) levels were noted at inclusion and after 8 weeks. Ambulatory BP monitoring (ABPM) was carried out at study entry and at the end of week eight. RESULTS: A total of 49 patients (32 patients in the atorvastatin group and 17 patients in the control group) completed the 3-month follow-up period of observation. The ABPM studies indicated significant reductions in total average systolic BP, total average diastolic BP, total average mean BP, day average systolic BP, day average diastolic BP, night average systolic BP, night average diastolic BP, and night average mean BP levels in the atorvastatin group, whereas these reductions were not observed in the control group. CONCLUSION: Our results indicate that atorvastatin therapy significantly improves BP control in hyperlipidemic hypertensive patients. However, the effects of other statins on BP, as well as, the different dosages need to be further investigated.

Antihypertensive Agents↗
PubMed2004

Serum levels of cardiac enzymes before and after renal transplantation.

BACKGROUND: Cardiac troponins are very sensitive and specific indicators of myocardial damage; however, they are sometimes found to be increased in patients with end-stage renal disease (ESRD). HYPOTHESIS: The aim of this study was to determine cardiac troponin I (cTpI) and creatine kinase myocardial isoform (CK-MB) levels and to assess their diagnostic and prognostic importance before and after renal transplantation. METHODS: Thirty-four patients with ESRD (mean age 31.8 +/- 8.6 years, 11 women) were enrolled. Serum levels of cTpI and CK-MB were measured pre- and postoperatively on Days 1, 7, and 30. Patients were followed up for cardiac events, and possible myocardial damage was investigated by exercise thallium-201-labeled myocardial perfusion scintigraphy. Mean cTpI levels were 0.24 +/- 0.11 ng/ml (preoperative), and 0.34 +/- 0.27 ng/ml (Day 1), 0.26 +/- 0.11 ng/ml (Day 7), and 0.28 +/- 0.30 ng/ml (Day 30). RESULTS: Compared with preoperative levels, cTpI was increased in 16 (47%), decreased in 6 (17.6%), and did not change in 12 (35.4%) patients. However, the increase did not exceed the myocardial infarction reference level of 2.3 ng/ml in any patient. Mean CK-MB levels were 12.6 (8.7U/l (preoperative), and 16.8 +/- 9.2U/l (Day 1), 16.3 +/- 8.1U/l (Day 7), and 13.3 +/- 6.6U/l (Day 30). Creatine kinase-MB was increased to above normal levels of 24 U/l in 13 (38.2%) patients on postoperative Days 1 or 7, and decreased to normal at the end of Month 1. No cardiac events occurred, and there was no abnormality in any patient on thallium scintigraphy. CONCLUSION: There was no significant difference in the levels of cTpI in patients with ESRD without cardiac events before and after renal transplantation (p > 0.05). Our findings show that cTpI has very high sensitivity and specificity for detecting cardiac damage in patients with ESRD after renal transplantation.

Adult↗
PubMed2004

Cor triatriatum dexter, atrial septal defect, and Ebstein's anomaly in an adult given a diagnosis by transthoracic and transesophageal echocardiography: a case report.

Cor triatriatum dexter is a very rare congenital abnormality in which the right atrium is divided into two chambers by a membrane. In this abnormality, there is a high incidence of associated congenital abnormalities, particularly of the right heart. In this case study, a 67-year-old man with Ebstein's anomaly, atrial septal defect, and cor triatriatum dexter is presented and echocardiography is discussed as a noninvasive diagnostic tool.

Aged↗
PubMed2004

Non-lipid effects of statins: emerging new indications.

Statins are beneficial both in the primary and secondary prevention of atherosclerotic vascular disease and acute events in a broad spectrum of patient subgroups. However, the observed clinical benefit with statin therapy is much greater than expected through the reduction of cholesterol levels alone. Clinical and experimental studies suggested that several antiatherosclerotic effects other than lipid lowering also contribute to the observed benefit of statin therapy. These 'pleiotropic effects' include improvement of endothelial function, antitrombotic actions, plaque stabilization, reduction of the vascular inflammatory process and anti-oxidation. Statins may also exhibit a wide variety of actions other than antiatherosclerotic effects. Recent observational data documented a potential association between statin use and improvement of fracture risk in osteoporosis. Despite the lack of randomized trials, epidemiological and limited clinical data suggested that statins might retard the pathogenesis of Alzheimer's disease. Observational data indicated that the progression of aortic stenosis and valvular calcification might be delayed in statin users. In addition, the deterioration of congestive heart failure may be delayed with statins via anti-inflammatory, vascular endothelial and antiatherosclerotic actions. Furthermore, preliminary clinical studies suggested that, by their immunosuppressive actions statins might reduce the incidence of rejection following organ transplantation. Currently, there is not enough evidence to prescribe therapy for such patients. However, ongoing studies are exploring the role of statin therapy for these new indications. This review will discuss several non-lipid effects of statin therapy currently under investigation.

Animals↗
PubMed2004

Prevalence of coronary artery disease in patients undergoing valvular operation due to rheumatic involvement.

OBJECTIVE: Rheumatic heart disease is still a major health problem in developing countries. The impact of coronary artery disease (CAD) on or its relation to rheumatic fever is not well established. We aimed to evaluate the prevalence of CAD and atherosclerotic risk factors in patients who underwent valvular surgery due to rheumatic heart disease. METHODS: The records of 346 patients who had undergone rheumatic valvular surgery in a university hospital between 1996 and 2002 were evaluated. RESULTS: Coronary angiography was performed in 218 (63%) patients, of whom 41 (18.8%) had CAD. The mean age of the patients having CAD and normal coronary arteries were 57.3 and 50.5 years respectively (p<0.001). In the study population patients with CAD had significantly increased prevalence of diabetes mellitus (14.6% vs. 4.5%; p=0.02), hypertension (36.6% vs. 16.4%; p=0.003), smoking (51.2% vs. 23.2%; p=0.001) and family history of CAD (39.5% vs. 20.0%; p=0.01) compared to patients with normal coronary arteries. However, the prevalence of dyslipidemia was similar in both groups (45.9% vs. 36.4%; p=0.1). CONCLUSION: These findings suggest that coronary artery disease prevalence in rheumatic valvular disease patients is similar to the normal population of same age. In cases where invasive assessment of valvular lesions is not indicated we suggest coronary angiography to be performed only in patients having clinical suspicion of CAD or multiple risk factors.

Adult↗