Biomedical subjects

Burak Pamukcu

Publications and source records attributed to Burak Pamukcu.

9 recordsLinked to original sources

PubMed2007

Association of metabolic syndrome with impaired heart rate recovery and low exercise capacity in young male adults.

BACKGROUND: Impaired heart rate recovery (HRR) is a powerful predictor of overall mortality. AIM: The aim of the present study is to assess HRR in young adult males with metabolic syndrome and to compare HRR with those of obese patients who do not meet the criteria for metabolic syndrome. PATIENTS AND METHODS: Sixty-four newly diagnosed and untreated young male subjects (24 +/- 3 years) with metabolic syndrome and 40 age and sex matched obese or overweight control subjects (ages 23 +/- 3 years) were enrolled in the study. All subjects performed a symptom limited exercise stress test under the standard Bruce protocol. HRR was calculated in the first, second and third minutes of the recovery period. The relationship between metabolic syndrome and HRR was evaluated via logistic regression analysis and a P-value < 0.05 was accepted as significant. RESULTS: Body mass index (BMI) was 38.6 +/- 3.68 and 32.22 +/- 2.99 kg/m(2) in the study and control groups, respectively (P < 0.001). Total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, systolic and diastolic blood pressures and fasting glucose levels were significantly higher in the study group. HRR in the first minute of the recovery period and mean exercise capacity were significantly lower in the study-group patients with metabolic syndrome (P < 0.001 and P = 0.012, respectively). CONCLUSION: We determined that HRR was impaired in young adult males with metabolic syndrome compared with obese ones who do not meet the criteria of metabolic syndrome. This decreased HRR may have prognostic value in the prediction of vascular events in patients with metabolic syndrome.

Adult↗

PubMed2006

A review of aspirin resistance; definition, possible mechanisms, detection with platelet function tests, and its clinical outcomes.

Aspirin (acetylsalicylic acid) is one of the main therapeutics in prevention of thrombo-embolic vascular events. Its efficiency is proved in the prevention of cardiovascular events. However, antiplatelet effect of aspirin is not absolute in all patients and some patients experience thrombo-embolic events despite aspirin. These patients are clinically called as aspirin resistant or aspirin non-responders. Globally, a lot of people are affected by aspirin resistance according to the high prevalence of athero-thrombotic vascular diseases. A prevalence of 5.5-45% in patients with various cardiovascular disease by different laboratory methods has been reported for aspirin resistance. Clinical outcome of aspirin resistance has been demonstrated in patients with different vascular diseases. Detection of platelet function in patients treated with aspirin may be necessary in the prediction of clinical outcome. Point of care methods, which have correlated results with the standard light transmittance aggregometry may be appropriate choices in the detection of platelets' response to antiplatelet therapy. Adequate additional therapies may reduce atherothrombotic risks and major cardiovascular events rate in aspirin resistant subjects. None of the current researches advised the cessation of aspirin therapy. There is need to investigate the efficacy of additional adenosine diphosphate receptor antagonists or newer antiplatelet agents in aspirin resistant subjects. The intent of this paper is to review the literature discussing possible mechanisms, determination techniques, and clinical effects of aspirin resistance.

Aspirin↗

PubMed2006

Endothelial function in patients with obstructive sleep apnea syndrome but without hypertension.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) influences endothelial function and causes hypertension. OBJECTIVES: Our aim was to evaluate the role of endothelial dysfunction in the pathogenesis of hypertension in OSAS. METHODS: Twenty-three patients with OSAS but without hypertension and 15 healthy normotensive subjects were investigated. The presence or absence of OSAS was evaluated with a sleep study. Endothelial function was investigated with brachial artery ultrasound examination. RESULTS: Baseline characteristics were equivalent between the two groups. Minimal oxygen saturation and apnea-hypopnea indexes in the OSAS and control groups were 62.9 +/- 16.5 versus 94.9 +/- 1.1% (p < 0.0001) and 53.1 +/- 20.3 versus 3.8 +/- 0.9 (p < 0.0001), respectively. There was not statistically significant difference between basal brachial artery diameters measured in the morning and in the evening in all groups. Flow-mediated dilation (FMD) values measured in the morning were lower than those measured in the evening in both OSAS patients and the control group: FMD of OSAS patients was 6.04 +/- 3.18% in the morning and 10.38 +/- 4.23% in the evening hours (p = 0.001), and FMD of control subjects was 10.9 +/- 2.6% in the morning and 13.9 +/- 2.32 in the evening hours (p = 0.002). Differences in FMD values measured both in the morning and evening hours in OSAS patients were lower compared with those in control subjects (p < 0.0001 in the morning hours and p = 0.003 in the evening hours). CONCLUSIONS: We detected a prominent diurnal deterioration in endothelial function in normotensive OSAS patients compared with healthy subjects. This deterioration may occur due to ongoing hypoxemia during the night and it may be a possible cause of hypertension and atherosclerotic cardiovascular diseases in patients with OSAS.

Brachial Artery↗

PubMed2006

The role of aspirin resistance on outcome in patients with acute coronary syndrome and the effect of clopidogrel therapy in the prevention of major cardiovascular events.

BACKGROUND: Aspirin resistance may increase up to more then threefold the risk of major cardiovascular events (MACE) in patients with stable coronary artery disease. AIM: The aim of our study was to determine; the prevalence of aspirin resistance in patients with acute coronary syndromes, the role of aspirin resistance on outcome in the follow-up and the effect of clopidogrel therapy in the prevention of MACE in aspirin resistant subjects. MATERIAL AND METHODS: We detected the prevelance of aspirin resistance in 105 patients with acute coronary syndrome. Platelet functions were analyzed in Platelet Function Analyzer (PFA)-100 (Dade Behring, Germany) with collagen and/or epinephrine (Col/Epi) and collagen and/or ADP (Col/ADP) cartridges. Primary end points of the study were myocardial infarction, unstable angina, cardiac death. RESULTS: 19% (n = 20) of patients were aspirin resistant by PFA-100. In the follow-up, MACE occured in 9 patients (45%) with aspirin resistance and in 10 patients (11.7%) with aspirin sensitive platelet aggregation (p = 0.001). Multivariate analysis showed that aspirin resistance was an independant predictor of MACE. The prevalence of MACE in patients who were on clopidogrel treatment for 12 months were lower compared to those who were on a clopidogrel treatment for the first six months (p = 0.040). CONCLUSIONS: We determined that the MACE risk in patients with acute coronary syndromes having detected aspirin resistance, was higher at statistically significant levels compared to patients having aspirin sensitive platelet aggregation. Our results showed that aspirin resistance, was an independant predictor of MACE in patients with acute coronary syndrome.

Angina, Unstable↗

PubMed2006

Changes in endothelial function before and after renal transplantation.

Endothelial dysfunction is an early key event in the development of atherosclerotic cardiovascular disease observed in chronic renal failure patients. The role of renal transplantation (RTx) on endothelial dysfunction is still unclear. The aim of this study was to evaluate the endothelial function of chronic renal failure patients before RTx (while they were on hemodialysis, HD), and after RTx (at the 6th and 12th months) by a noninvasive method, brachial arterial ultrasound. A total of 22 (17 male, mean age: 33.9 +/- 11.6 years) RTx recipients were enrolled in the study. Endothelium-dependent vasodilation (EDD) was assessed by establishing reactive hyperemia. EDD prior to transplantation was significantly lower when compared with EDD measured at the 6th and 12th months after RTx (EDD pretransplantation: 6 +/- 3.7%, EDD at the 6th month of RTx: 8.3 +/- 2.3% and EDD at the 12th month of RTx: 12.1 +/- 3.6%, P < 0.001). When the EDD values measured at the 6th and 12th months of RTx were compared, measurements of the 12th month were found significantly higher than those of the 6th month (P < 0.001). Our results also showed that RTx has provided improvement in endothelial function by eliminating the uremic environment although not in the early post-RTx period.

Adolescent↗

PubMed2005

The role of exercise on platelet aggregation in patients with stable coronary artery disease: exercise induces aspirin resistant platelet activation.

OBJECTIVES: The aim of our study was to determine the relation between exercise stress test and aspirin resistance in patients with stable coronary artery disease. BACKGROUND: Clinically aspirin resistance is defined as having thrombotic and embolic cardiovascular events despite regular aspirin therapy. METHODS: We studied platelet functions of 62 patients with stable coronary artery disease and 20 subjects with normal coronary arteries by Platelet Function Analyzer (PFA-100, Dade Behring, Germany) at rest and after exertion with collagen and/or epinephrine (Col/Epi) and collagen and/or ADP cartridges. Closure time (CT)<186 seconds was defined as aspirin resistance with Col/Epi cartridges of PFA-100. Symptom limited treadmill stress test (protocol of Bruce) was performed with Oxford Streslink TD-1 system. RESULTS: 8 (12.9%) patients were aspirin resistant by PFA-100 (CT<186s despite regular aspirin therapy) at rest. At the first minute of the recovery period of exercise stress test 14 (22.5%) patients were aspirin resistant by PFA-100. CTs with Col/ADP were respectively 89+/-6 s (83--100s) and 89+/-5 s (82--104s) at rest and after exercise (p=0.107). 20.3% (11/54) of patients known as in vitro aspirin sensitives at rest had shorter CTs and 11.1% (6/54) had aspirin resistance after exercise (p=0.004). There was no statistically significiant difference in platelet functions in the control group after exertion. CONCLUSION: We conclude that 11.1% of in vitro aspirin sensitive subjects at rest had aspirin resistance after exercise by PFA-100. In some individuals, exercise induced platelet activation is aspirin insensitive at usual antiplatelet doses. We need further clinical trials to optimize antiplatelet therapy in patients with coronary artery disease.

Adult↗

PubMed2005

The role of platelet glycoprotein IIIa polymorphism in the high prevalence of in vitro aspirin resistance in patients with intracoronary stent restenosis.

OBJECTIVES: The aim of our study was to determine the relation between platelet glycoprotein IIIa (Pl A ) polymorphism and aspirin resistance in patients with intracoronary stent restenosis. BACKGROUND: Clinically, aspirin resistance is defined as having thrombotic and embolic cardiovascular events despite regular aspirin therapy. Platelet glycoprotein IIIa polymorphism is said to be a possible mechanism of aspirin resistance. METHODS: We studied the prevalence of aspirin resistance in 204 previously intracoronary stent-implanted patients with stable coronary artery disease. In 102 of these patients, intracoronary stent restenosis was present. Platelet functions were analyzed in a platelet function analyzer (PFA-100, Dade Behring, Germany) with collagen and/or epinephrine (Col/Epi) and collagen and/or adenosine diphosphate cartridges. Closure time <186 seconds was defined as aspirin resistance with Col/Epi cartridges of PFA-100. The Pl A polymorphisms of 43 aspirin-resistant and 51 aspirin-sensitive subjects were determined with polymerase chain reaction and restriction fragments length polymorphism. RESULTS: A total of 31.3% (n = 32) of patients with intracoronary stent restenosis and 10.7% (n = 11) of patients with patent intracoronary stents were resistant to aspirin by PFA-100. The Pl A1,A1 allele of glycoprotein IIIa was present in 36 subjects (83.7.%) and the Pl A1,A2 allele was present in 7 subjects (16.2.%) in the aspirin-resistant patients group. The Pl A1,A1 allele of glycoprotein IIIa was present in 37 subjects (72.5%) and the Pl A1,A2 allele was present in 14 subjects (27.5%) in the aspirin-sensitive patients group ( P = .195). CONCLUSION: Our results suggest that platelets of patients with intracoronary stent restenosis with or without Pl A2 heterozygosity of glycoprotein IIIa are more likely to be resistant to low-dose aspirin therapy.

Aged↗

PubMed2005

Biventricular diastolic dysfunction in patients with autosomal-dominant polycystic kidney disease.

BACKGROUND: Left ventricular diastolic dysfunction has been shown in patients with autosomal-dominant polycystic kidney disease (ADPKD). However, there is no study evaluating right ventricular functions in these patients. METHODS: In the present study, diastolic functions of both ventricles in normotensive and hypertensive ADPKD patients with well-preserved renal function were investigated. Fifteen hypertensive and 16 normotensive patients with ADPKD with well-preserved renal function, 16 patients with essential hypertension, and 24 healthy subjects were included in the study. Conventional left and right ventricular echocardiographic measurements were performed in all subjects. Left and right ventricular functions were investigated both by myocardial performance index (MPI) [calculated by dividing the sum of isovolumic contraction time and isovolumic relaxation time (IVRT) by ejection time] and by tissue Doppler imaging (TDI). RESULTS: Left ventricular deceleration time and IVRT were significantly prolonged in hypertensive patients with ADPKD compared with patients with essential hypertension and even in normotensive patients with ADPKD compared with healthy subjects. Left and right MPIs were significantly higher in patients with ADPKD compared with healthy subjects, showing systolic and diastolic dysfunction. Moreover, by using TDI, the peak early diastolic mitral annular velocity (Em) to peak late diastolic mitral annular velocity (Am) ratio and the peak early diastolic tricuspid annular velocity (Et) to peak late diastolic tricuspid annular velocity (At) ratio were decreased in patients with ADPKD, suggesting biventricular diastolic dysfunction. CONCLUSION: Both hypertensive and normotensive patients with ADPKD show significant biventricular diastolic dysfunction, suggesting cardiac involvement very early in the course of ADPKD.

Adult↗

PubMedDate not supplied

Non-invasive evaluation of endothelial function in hypertensive elderly patients.

Impaired endothelium-dependent vasomotion is a diffuse disease process resulting in abnormal regulation of blood vessel tone and loss of several atheroprotective effects of the normal endothelium. The aim of the present study was to investigate the effects of aging and hypertension on endothelial function. Sixty-six geriatric subjects with ages over 60 (48 hypertensive and 18 healthy) and 40 middle-aged subjects (16 hypertensive and 24 healthy) were included in the study. Systemic vascular endothelial function was evaluated through measuring brachial arterial vasodilation, a physiologic answer to reactive hyperemia occured with increased blood flow in the vessel after transient ischemia (flow-mediated dilation, FMD%), and with carotid artery intima-media thickness (IMT) measurement, using high-resolution ultrasonography. Endothelial independent vasodilation was also measured after administration of sublingual isosorbide dinitrate (isosorbide dinitrate mediated dilation, IDNMD%). FMD% was significantly decreased in elderly and/or hypertensive (HT) patients (geriatric HT: 9.5 +/- 4.7%, geriatric non-HT: 12.7 +/- 5.5%, middle-aged HT: 12.9 +/- 4.3% and middle-aged non-HT: 18.9 +/- 8.1%) (geriatric HT versus geriatric non-HT (P = 0.02), geriatric HT versus middle-aged HT (P = 0.01), geriatric non-HT versus middle-aged non-HT (P = 0.008)). Both FMD% and IDNMD% were inversely correlated with age, baseline vessel diameter and carotid artery intima-media thickness. FMD% was also inversely correlated with diastolic blood pressure. No correlation was found between FMD% and systolic blood pressure, serum cholesterol and triglyceride levels. Endothelium dependent (EDD) and independent dilatation of large arteries decreased with aging even in the healthy elderly, and FMD further declined in HT elderly patients, indicating that age and hypertension independently impair endothelial function. Positive correlations with age and hypertension, and significant inverse correlation with FMD, makes carotid artery IMT a possible indicator of endothelial function.

Adult↗