Biomedical subjects

Tayfun Sahin

Publications and source records attributed to Tayfun Sahin.

11 recordsLinked to original sources

PubMed2007

The frequency of aspirin resistance and its risk factors in patients with metabolic syndrome.

BACKGROUND: Although different populations were examined for the incidence of aspirin resistance, the frequency and related risk factors for aspirin resistance in patients with metabolic syndrome have not been reported yet. This study aimed to determine the frequency of aspirin resistance and its risk factors in patients with metabolic syndrome. METHODS: We performed a cross-sectional study in 110 patients with metabolic syndrome. After one week of 100 mg/day aspirin, blood samples were obtained. Platelet function analyzer (PFA-100) was used to determine the frequency of aspirin resistance. Endothelial functions, carotid intima media thickness, and the presence of plaques in the carotid arteries were evaluated for subclinical atherosclerosis and the levels of inflammatory markers were assessed as risk factors for aspirin resistance. The presence of subclinical atherosclerosis was defined as a maximum carotid intima media thickness of > or = 0.9 mm and/or the presence of carotid atheroma. RESULTS: Aspirin resistance was detected in 21.9% of the patients. In the multivariate analysis, hs-CRP levels (odds ratio [95% CI]=2.8 [1.3-5.9], p=0.009), diastolic blood pressure, (0.9 [0.8-1.0], p=0.007), and the presence of subclinical atherosclerosis (4.1 [1.4-12.2], p=0.012) were statistically significant risk factors for aspirin resistance. CONCLUSIONS: We concluded that the frequency of aspirin resistance confirmed in this cohort of patients with metabolic syndrome was higher in patients with a lower diastolic blood pressure, higher hs-CRP levels and atherosclerotic changes in their carotid arteries.

Adult↗

PubMed2006

Silent cerebral infarction in patients with dilated cardiomyopathy: echocardiographic correlates.

BACKGROUND: Patients with dilated cardiomyopathy (DCM) have an increased risk of thromboembolic events. Incidence of silent cerebral infarction (SCI) has not been investigated in these patients. The aim of this study was to investigate the incidence of SCI in patients with DCM and to determine its associations with echocardiographic parameters. METHODS AND RESULTS: Seventy-two patients (mean age 62+/-12 years) with DCM underwent cranial magnetic resonance imaging in addition to transthoracic and transesophageal echocardiographic examination. A total of 56 age-matched healthy volunteers served as a control group for comparison SCI prevalence. Prevalence of SCI was significantly higher in patients with DCM (35% vs. 3.6%; p<0.001). In DCM group, patients with SCI had significantly impaired left ventricular systolic function, higher frequency of restrictive diastolic filling, moderate to severe left atrial spontaneous echo contrast (SEC), aortic SEC, and complex atherosclerosis or calcified plaques in the aorta. In logistic regression analysis, type of diastolic filling emerged as the only independent risk factor for SCI (p<0.001). When the type of diastolic filling was removed from the analysis, ejection fraction, marked left atrial SEC, complex-calcified aortic atheroma and age appeared as the other independent risk factors (p = 0.003, p = 0.009, p = 0.013 and p = 0.018, respectively). CONCLUSION: SCI is a frequent finding in DCM patients. Impaired systolic function, restrictive filling pattern, presence of moderate to severe left atrial SEC, and complex atherosclerosis in the aorta are the factors contributing to the development of SCI.

Adult↗

PubMed2006

Endothelial dysfunction in patients with ulcerative colitis.

BACKGROUND: Human intestinal microvessels from chronically inflamed ulcerative colitis (UC) show microvascular endothelial dysfunction. Whether generalized endothelial dysfunction could associate with UC has not been explored yet. Our aim was to assess the endothelial function in the patients with different UC activity and to hypothesize about the relationship of endothelial function to activity-related extraintestinal complications (AREC) of UC. METHODS: Twelve patients with mild UC, 14 patients with moderate UC, 16 patients with severe UC, and 24 healthy subjects were included in the study. The activity of UC is calculated according to the Seo Index. Endothelial functions of the brachial artery were evaluated by using high-resolution vascular ultrasound. Endothelial-dependent dilatation (EDD) was assessed by establishing reactive hyperemia and endothelial-independent dilatation (EID) was determined by using sublingual isosorbide dinitrate. RESULTS: EDD was significantly worse in patients with severe UC as compared with patients with mild UC (8.7 +/- 1.6% versus 17.3 +/- 5.6%, P < 0.05) and even in patients with moderate UC as compared with patients with mild UC (13.1 +/- 3.2% versus 17.3 +/- 5.6%, P < 0.05). EDD was not significantly worse in patients with mild UC as compared with healthy subjects (17.3 +/- 5.6% versus 18.1 +/- 8.1%, P > 0.05). EID was significantly worse in patients with severe UC compared with patients with moderate UC (10.5 +/- 2.9% versus 13.4 +/- 3.7%, P < 0.05) and even in patients with mild UC compared with healthy subjects (20 +/- 6.7% versus 31.1 +/- 12.6%, P < 0.05). EDD and EID were significantly worse in patients with AREC compared with patients with no AREC (9.5 +/- 2.5% versus 14.9 +/- 5.1%, P < 0.05; 11.6 +/- 4.3% versus 16 +/- 6.1%, P < 0.05, respectively). CONCLUSIONS: Increased activity of UC is associated with significant endothelial dysfunction, which may relate to the pathophysiology of AREC of UC.

Adult↗

PubMed2005

Effect of cardiac resynchronization therapy on left atrial appendage function and pulmonary venous flow pattern.

BACKGROUND: Previous studies have shown improvement in left ventricular function and development of the reverse remodeling in the left ventricle and left atrium after cardiac resynchronization therapy (CRT). The aim of this study was to investigate the effect of CRT on left atrial appendage (LAA) function and pulmonary venous flow pattern. METHODS: Eighteen patients with systolic heart failure and complete left bundle branch block underwent implantation of biventricular pacemaker devices. In order to follow changes in LAA, transthoracic and transesophageal echocardiographic examinations were performed 1 week before and repeated 1 and 6 months after pacemaker implantation. RESULTS: CRT resulted in significant clinical improvement and decrease in NYHA functional class in 17 patients (94%). Maximum and minimum areas of left atrial appendage (LAAAmax and LAAAmin) decreased, with a concomitant increase in LAA ejection fraction. [LAAAmax: from 4.6+/-2 to 4.2+/-1.8 cm2 at the first (P < 0.001) and to 4.0+/-1.8 cm2 at the sixth month (P < 0.001); LAAAmin: from 2.7+/-1.3 to 2.3+/-1.2 cm2 at the first (P < 0.001) and to 2.2+/-1.2 cm2 at the sixth month (P < 0.001) and LAA ejection fraction: from 41+/-12% to 46+/-10% at the first (P = 0.007) and to 47+/-8% at the sixth month (P = 0.003)]. LAA active emptying and filling flow and pulmonary venous systolic velocities also increased after CRT. The appendage active emptying velocity correlated significantly with left ventricular ejection fraction (r = 0.50, P = 0.002), LAA ejection fraction (r = 0.51, P = 0.002), left atrial maximal volume, LAVmax (r = -0.44, P = 0.007), left atrial minimal volume, LAVmin (r = -0.50, P = 0.002) and pulmonary vein systolic flow velocity (r = 0.33, P = 0.05). CONCLUSION: Treatment of heart failure by CRT results with marked improvements in LAA function and increases pulmonary venous systolic velocity.

Adult↗

PubMed2005

Relation between free triiodothyronine/free thyroxine ratio, echocardiographic parameters and mortality in dilated cardiomyopathy.

BACKGROUND: Abnormalities in thyroid function are frequent in patients with heart failure and are associated with increased mortality. However, the relation between thyroid hormone levels and echocardiographic parameters has not been investigated sufficiently. AIM: The aims of this study were to investigate the correlations of thyroid hormone levels with echocardiographic parameters and to evaluate their associations with subsequent mortality in a group of patients with dilated cardiomyopathy (DCMP). METHODS: Serum levels of thyroid hormones were measured in 111 consecutive patients with DCMP (35 female, 76 male, mean age: 62+/-12 years). All patients underwent echocardiographic examination and were followed-up for a period of 12+/-8 months. RESULTS: Twenty-three patients (21%) had abnormalities in thyroid function tests. Free triiodothyronine (fT3)/free thyroxine (fT4) ratio was significantly correlated with most of echocardiographic parameters, such as chamber diameters and ejection fraction. Sixteen patients (14%) died during the follow-up period; their fT3/fT4 ratio was significantly lower than the patients who survived (1.31+/-0.37 vs. 2.01+/-0.72, p<0.001). A fT3/fT4 ratio of <or=1.7 was associated with an increased risk of mortality (p<0.001), independent of other prognostic markers. Sensitivity, specificity, positive and negative predictivity of fT3/fT4 ratio <or=1.7 for cardiac mortality were 100%, 71%, 36% and 100%, respectively. CONCLUSION: Determination of FT3/FT4 ratio may be a valuable and simple predictor for identification of patients with DCMP who are at high risk of subsequent mortality.

Adult↗

PubMed2005

Assessment of left ventricular function and volumes for patients with dilated cardiomyopathy using gated myocardial perfusion SPECT and comparison with echocardiography.

AIM: Left ventricular function, volumes and regional wall motion provide valuable diagnostic information and are of long-term prognostic importance in patients with dilated cardiomyopathy (DCM). This study was designed to compare the effectiveness of two-dimensional echocardiography and gated single photon emission computed tomography (SPECT) to evaluate these parameters in patients with DCM. METHODS: Gated SPECT and two-dimensional echocardiography were performed in 45 patients with DCM, and in 10 normal subjects as the control group. Patients were divided into two groups according to the aetiology of DCM: group I, ischaemic DCM (n=30); group II, non-ischaemic DCM (n=15). All patients and the control group underwent resting myocardial gated SPECT, 45 min after injection of 555 MBq of Tc-methoxyisobutyl-isonitrile (Tc-MIBI). Gated SPECT data, including left ventricular volumes and left ventricular ejection fraction (LVEF), were processed using an automated algorithm. Simpson's method was used to evaluate these parameters. Regional wall motion was evaluated using both modalities and scored using a 16-segment model with a five-point scoring system. Perfusion defects were expressed as a percentage of the whole myocardium planimetered by a bull's-eye polar map of composite non-gated SPECT. Myocardial perfusion was scored using a 16-segment model with a four-point scoring system. RESULTS: Mean perfusion defects and perfusion defect scores were 25+/-13% and 1.12+/-0.36 in group I and 4+/-8% and 0.76+/-0.26 in group II (P<0.01). The overall agreement between the two imaging modalities for the assessment of regional wall motion was 57% (403/720 segments: 269/480 segments in group I and 134/240 segments in group II). With gated SPECT, LVEF was 27+/-9%, the end-diastolic volume (EDV) was 212+/-71 ml and the end-systolic volume (ESV) was 160+/-67 ml. With echocardiography, these values were 29+/-8%, 197+/-56 ml and 139+/-47 ml, respectively. The correlation between gated SPECT and two-dimensional echocardiography was good (r=0.72, P<0.01) for the assessment of LVEF. The correlation was also good for EDV and ESV, but with wider limits of agreement (r= 0.71, P<0.01 and r=0.71, P<0.01, respectively) and with significantly higher values with gated SPECT (P<0.01). For patients with a perfusion defect of <20% or low myocardial perfusion scores, a higher correlation was found between the two methods for the assessment of LVEF, EDV and ESV. On the other hand, the correlation was lower for the assessment of wall motion. CONCLUSIONS: Gated SPECT and two-dimensional echocardiography correlate well for the assessment of left ventricular function and volumes. Gated SPECT has the advantage of providing information about left ventricular function, dimensions and perfusion.

Adult↗

PubMed2005

Effect of cardiac resynchronization therapy on left ventricular diastolic filling pattern in responder and nonresponder patients.

BACKGROUND: The aim of this study was to investigate the short- and long-term effects of cardiac resynchronization therapy (CRT) on left ventricular (LV) diastolic filling pattern and the relation between the diastolic filling pattern and the response to CRT. METHODS: Twenty-three patients with systolic heart failure and complete left bundle-branch block underwent implantation of biventricular pacemaker devices. In order to follow the changes in diastolic function, mitral inflow, pulmonary venous flow, and LV flow propagation (Vp) velocities were measured with pulsed-wave and color M-mode Doppler echocardiography 1 week before and 1 and 6 months after pacemaker implantation. At the 6-month follow-up, patients were divided into two groups according to their response to CRT defined as a relative increase in LV ejection fraction (LVEF) > or =25% versus baseline. RESULTS: After biventricular pacemaker implantation, significant clinical improvement was observed in all patients. Compared to baseline, the ratio of early-to-late peak velocities (E/A) decreased significantly at the 6th month (E/A ratio: from 1.5 +/- 0.9 to 0.8 +/- 0.5 at the 6th month (P = 0.02)). Pulmonary systolic flow to diastolic flow ratio (PVs/PVd) increased with CRT after 6 months (PVs/PVd ratio: from 0.9 +/- 0.4 to 1.3 +/- 0.7 at the 6th month (P = 0.02)). E/Vp ratio decreased significantly at the 1st and 6th month (E/Vp ratio: from 2.7 +/- 0.8 to 2 +/- 0.8 at the 1st (P < 0.002) and to 1.9 +/- 0.7 at the 6th month (P < 0.02)). In responders (n: 17, 74%), E wave and PVra velocity decreased, E-wave deceleration time increased, and E/Vp ratio improved significantly, whereas in nonresponders, changes in LV diastolic parameters remained insignificant. However, diastolic filling pattern improved significantly at the 1st and 6th month of CRT in both responders and nonresponders. CONCLUSION: CRT enhances diastolic filling patterns in both responder and nonresponder patients. This may be related to improvement in symptoms even in nonresponders who have a relative increase in LVEF <25%.

Bundle-Branch Block↗

PubMed2005

Effect of rosiglitazone on insulin resistance, C-reactive protein and endothelial function in non-obese young women with polycystic ovary syndrome.

OBJECTIVE: Women with polycystic ovary syndrome (PCOS) exhibit elevated levels of serum C-reactive protein (CRP) and impaired endothelium dysfunction which are directly correlated with insulin resistance. Because rosiglitazone improves insulin sensitivity, we tested whether rosiglitazone treatment ameliorates high-sensitivity (hs)CRP levels and endothelial dysfunction in these patients. DESIGN: Thirty-one women with PCOS were recruited (mean age, 24.7+/-3.9 (s.e.) years; mean body mass index (BMI), 25.6+/-3.2 kg/m2). All women were treated with 4 mg rosiglitazone daily for 12 months. METHODS: Serum levels of testosterone, LH, FSH, sex hormone-binding globulin (SHBG), insulin and hsCRP were measured. The BMI, hirsutism scores and insulin sensitivity indices were calculated before and after treatment. Arterial endothelium and smooth muscle function was measured by examining brachial artery responses to endothelium-dependent and endothelium-independent stimuli before and after treatment. RESULTS: After treatment with rosigitazone there were significant decreases in serum testosterone (91.2+/-37.5 vs 56.1+/-21.8 ng/dl; P < 0.01) and fasting insulin concentrations (12.5+/-7.6 vs 8.75+/-4.03 microU/ml; P = 0.015). Insulin resistance indices were significantly improved after rosiglitazone treatment (P < 0.05). There were no significant changes in BMI, waist circumference, serum total cholesterol, low-density lipoprotein (LDL)-cholesterol, FSH and LH levels. Hirsutism score was decreased significantly after treatment (10.8+/-1.8 vs 7.6+/-1.7; P < 0.05). Twenty-four of the women reverted to regular menstrual cycles. Levels of SHBG increased significantly after treatment (28.7+/-8.7 vs 48.4+/-11.2 nmol/l; P < 0.01). Serum hsCRP levels were decreased significantly after rosiglitazone treatment (0.25+/-0.1 vs 0.09+/-0.02 mg/dl; P = 0.006). There was also significant improvement in endothelium-dependent vascular responses after rosiglitazone treatment (9.9+/-3.9 vs 16.4+/-5.1%; P < 0.01). CONCLUSIONS: We conclude that rosiglitazone treatment improves insulin sensitivity in women with PCOS. It also decreases androgen production without significant weight gain. More importantly, it has beneficial effects on endothelial dysfunction and low-grade chronic inflammation in normal weight young women with PCOS.

Adult↗

PubMed2004

Endothelial dysfunction in young women with polycystic ovary syndrome: relationship with insulin resistance and low-grade chronic inflammation.

Women with polycystic ovary syndrome (PCOS) carry a number of cardiovascular risk factors. Cardiovascular morbidity is elevated even in young women with PCOS. Low-grade chronic inflammation, reflected in elevated levels of serum C-reactive protein (CRP) and endothelial dysfunction have recently been linked to development of atherosclerosis. We compared high-sensitivity (hs)CRP concentrations and endothelium dysfunction in 37 women with PCOS and 25 control subjects matched as a group for age and body mass index (BMI). Arterial endothelium and smooth muscle function was measured by examining brachial artery responses to endothelium-dependent and endothelium-independent stimuli. Serum LH, testosterone, androstenedione, and fasting insulin levels were significantly higher in the PCOS group than the control group. The PCOS group was more insulin resistant than age- and BMI-matched control women. CRP concentrations were higher in PCOS women than the healthy control group (0.25 vs. 0.09 mg/dl). hsCRP concentrations were correlated with BMI, insulin sensitivity indices (homeostasis model assessment and quantitative insulin sensitivity check index), and endothelium-dependent vasodilation. The groups were well matched for baseline brachial artery diameter. There was a significant difference in endothelium-dependent (flow- mediated dilation) and endothelium-independent (sublingual nitroglycerin) vascular responses between the women with PCOS and the normal healthy control group (P = 0.002 and P = 0.01, respectively). Endothelium-dependent vasodilation was correlated with hsCRP concentrations and insulin resistance. In conclusion, this study is the first to demonstrate increased levels of hsCRP, endothelial dysfunction, and the relation with insulin resistance in young and normal-weight women with PCOS. Clinical strategies aimed at reducing insulin resistance may prevent early atherosclerosis in women with PCOS.

Adult↗

PubMed2004

Effect of cardiac resynchronization therapy on left atrial reverse remodeling and spontaneous echo contrast.

Recent studies revealed reverse remodeling in left ventricle with cardiac resynchronization therapy (CRT). However, effects on left atrial remodeling, left atrial total emptying fraction and left atrial spontaneous echo contrast (SEC) have not been adequately evaluated. The aim of this study was to investigate the long-term changes in SEC, left atrial reverse remodeling, and left atrial total emptying fraction after CRT. Twenty patients with systolic heart failure and complete left bundle-branch block underwent implantation of biventricular pacemaker devices. Transthoracic and transesophageal echocardiography were performed one week before and one and six months after pacemaker implantation. After biventricular pacemaker implantation, significant clinical improvement was observed in all patients. Left atrial maximal and minimal volumes showed a significant progressive decline after CRT (reverse remodeling). Left atrial total emptying ejection fraction (LATEF) was 33 +/- 19% at baseline and increased to 37 +/- 10% and 41 +/- 11% at the 1st and 6th months respectively (p = 0.01 and p = 0.04). SEC was detected in 18 of 20 patients (90%) at the beginning of the study. After six months SEC disappeared in 5 patients and frequency of SEC reduced to 45%. Decrease in the intensity of the SEC was also statistically significant (at the 1st and 6th months; p = 0.001 and p < 0.001 respectively). Long-term CRT results in atrial reverse remodeling, increases LATEF, and reduces both frequency and intensity of atrial SEC.

Adult↗

PubMedDate not supplied

Evaluation of anthracycline-induced early left ventricular dysfunction in children with cancer: a comparative study with echocardiography and multigated radionuclide angiography.

The study aimed to compare diastolic and systolic dysfunctions detected by echocardiography (ECHO) and multigated radionuclide angiography (MUGA) in patients with cancer in the first 3 months after anthracycline-comprising chemotherapy. Children with leukemia and solid tumors who had anthracycline-comprising chemotherapy were enrolled in the study. ECHO and MUGA were performed in all patients before the first chemotherapy course and in the first 3 month of completing anthracycline-comprising chemotherapy. Cumulative anthracycline doses per body surface were calculated. Left ventricular systolic and diastolic functions were measured by both techniques. Twenty-one patients with a median age of 6.9 +/- 3.6 years were enrolled in the study. Mean cumulative anthracycline doses were equivalent to 276 +/- 83 mg/m2 doxorubicin. After anthracycline chemotherapy, cardiac dysfunction was detected in 14 and 48% of the patients by ECHO and MUGA, respectively. All dysfunctions detected by ECHO were systolic, whereas 29% of the patients had diastolic and 38% of the patients had systolic dysfunction in MUGA study. Although the study group is small, MUGA seems more sensitive in detecting anthracycline-induced systolic and diastolic cardiac dysfunctions compared to ECHO.

Adolescent↗