Mehmet Meriç

Evaluation of Endothelial Function in Subclinical Hypothyroidism and Subclinical Hyperthyroidism

Subclinical hypothyroidism and subclinical hyperthyroidism are two frequently occurring conditions for which exact therapeutic approaches have not yet been established. The aim of this study was to compare the endothelial function and carotid artery intimae-media thickness (IMT) of these two groups of patients to euthyroid subjects and to assess the effects of these conditions on endothelial function. Study groups comprised of 25 subclinical hypothyroid patients (mean age, 32.28 +/- 9.67 years), 13 subclinical hyperthyroid patients (mean age, 35.69 +/- 9.67 years), and 23 euthyroid subjects (mean age, 35.87 +/- 7.93 years). They were evaluated for flow-mediated dilatation (FMD), and carotid artery IMT. The groups were matched strictly for atherosclerotic risk factors. The subclinical hypothyroid group was found to have significantly lower FMD values. No significant differences were observed between the groups with respect to other vascular parameters. The only discriminative factor between the groups was the state of their thyroid function. Therefore, subclinical hypothyroidism may have adverse effects on endothelial function independent from other well-known atherosclerotic risk factors.

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.

AbstractBackground: 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.

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.

Association of haematological indices with the degree of microvascular injury in patients with acute anterior wall myocardial infarction treated with primary percutaneous coronary intervention

Background: In acute myocardial infarction (AMI), increased neutrophil count has been associated with more severe coronary artery disease and larger infarct size. Increased mean platelet volume (MPV) is also associated with poor clinical outcome and impaired angiographic reperfusion in patients with AMI. However, the associations of neutrophil count and MPV with the indices of tissue level reperfusion were not fully elucidated. Aim: To elucidate the relationship between baseline neutrophil count and MPV on presentation and microvascular injury in patients with anterior AMI treated with primary percutaneous coronary intervention (pPCI). Methods: 41 patients with anterior wall AMI treated successfully with pPCI were included. The leucocyte count, neutrophil count and MPV were obtained on admission, and the percentage of neutrophils was calculated. After PCI thrombolysis in myocardial infarction, grade 3 flow was established in all patients. The coronary flow velocity pattern (diastolic deceleration time (DDT)) was examined with transthoracic echocardiography and measured intracoronary pressures with fibreoptic pressure–temperature sensor-tipped guidewire in the left anterior descending artery within 48 h after pPCI. Thermodilution-derived coronary flow reserve (CFR) was calculated. Index of microvascular resistance (IMR) was defined as simultaneously measured distal coronary pressure divided by the inverse of the thermodilution-derived hyperaemic mean transit time. Subsequently, a short compliant balloon was placed in the stented segment and inflated to measure coronary wedge pressure (CWP). Results: Higher neutrophil counts were strongly associated with higher IMR (r = 0.86, p<0.001), lower CFR (r = −0.60, p<0.001), shorter DDT (r = −0.73, p<0.001) and higher CWP (r = 0.73, p<0.001). Likewise, there were significant correlations among the percentage of neutrophils and CFR (r = −0.34, p = 0.02), IMR (r = 0.46, p = 0.002), DDT (r = −0.36, p = 0.01) and CWP (r = 0.49, p = 0.001). Relationships among leucocyte count and IMR (r = 0.38, p = 0.01), CFR (r = −0.33, p =  0.03), DDT (r = −0.36, p = 0.01) and CWP (r = 0.32, p = 0.026) were slightly significant. Higher neutrophil count remained independently associated with indices of microvascular perfusion in multivariable models controlling for age, smoking habits and time to treatment. Also, higher MPV on admission was strongly associated with higher IMR (r = 0.89, p<0.001), steeper DDT (r = −0.64, p<0.001), lower CFR (r = −0.43, p = 0.004) and higher CWP (r = 0.77, p<0.001). Conclusion: Absolute and relative neutrophilia and higher MPV on admission were independently associated with impaired microvascular perfusion in patients with anterior AMI treated with pPCI. It is possible that neutrophilia and high MPV are simple surrogate markers of worse microvascular injury in patients with AMI.

Clinical relevance of aspirin resistance in patients with stable coronary artery disease: a prospective follow-up study (PROSPECTAR).

Aspirin resistance may increase the risk of major adverse cardiac events (MACE) more than threefold in patients with stable coronary artery disease (CAD). This study aimed to determine the prevalence of aspirin resistance in patients with stable CAD, the role of aspirin resistance on outcome in the follow-up, and the effect of clopidogrel therapy in MACE prevention in aspirin-resistant individuals. We detected the prevalence of aspirin resistance in 234 patients with stable CAD. Platelet function was determined by PFA-100 with collagen and/or epinephrine and collagen and/or ADP cartridges. The mean follow-up time was 20.6 ± 6.9 months. The primary endpoints of the study were occurrence of myocardial infarction, unstable angina, stroke and cardiac death. Of patients, 22.2% (n = 52) were aspirin resistant by PFA-100. During follow-up, MACE occurred in eight patients (15.4%) with aspirin resistance and in 20 patients (11.0%) with aspirin-sensitive platelet aggregation (P = 0.269). MACE increased in aspirin-resistant patients after termination of clopidogrel therapy. Eleven patients experienced MACE after cessation of clopidogrel therapy (P < 0.001). The MACE risk in patients with stable CAD having detected aspirin resistance was similar compared with patients having aspirin-sensitive platelet aggregation by PFA-100. The MACE prevalence increased during follow-up, however, just after cessation of clopidogrel therapy.

The use of human heart-type fatty acid-binding protein as an early diagnostic biochemical marker of myocardial necrosis in patients with acute coronary syndrome, and its comparison with troponin-T and creatine kinase–myocardial band

Heart-type fatty acid-binding protein (H-FABP), a new biochemical marker of sarcolemmal injury due to acute myocardial ischemia, can be used as a tool in early diagnosis and management of patients at high risk. The aim of this study was to determine the early diagnostic value of H-FABP in acute coronary syndrome (within 6–24 h of chest pain) and to compare it with troponin-T (TnT) and creatine kinase–myocardial band (CK-MB) for accuracy. The study consisted of 40 consecutive patients with chest pain admitted to the coronary care unit with the diagnosis of suspected acute coronary syndrome. The patient population consisted of two groups according to the time of admission; the first group (26 patients) included patients admitted within 6 h of chest pain, and the second group (14 patients) included patients admitted within 6–24 h of chest pain. The blood samples for H-FABP, TnT, and CK-MB were obtained at admittance, at the 6th, and at the 24th hours for the first group, and at admittance and at the 24th hours for the second. Statistical analysis was performed among the 26 patients for the first 6 h values, and among all 40 patients for the values obtained within 6–24 h and at the 24th hour. The patients were then divided into groups according to the changes in the electrocardiogram (ECG) and cardiac enzymes as unstable angina pectoris, non-ST elevation myocardial infarction (MI), and ST-elevation MI. Coronary angiography was performed in 38 (95%) patients. Sensitivity of TnT, CK-MB, and H-FABP in the first group (within 6 h of chest pain) were 38%, 76%, and 95% respectively. The sensitivity of H-FABP was significantly higher than TnT (P = 0.014). Sensitivity of TnT, CK-MB, and H-FABP tests in the second time period (within 6–24 h of chest pain) were 100%, 90%, and 91% respectively. In this time period, the sensitivity of TnT was higher than H-FABP, but it was statistically insignificant. At the 24th hour, sensitivity of TnT was 100%, CK-MB 90%, and H-FABP 27.3%, and TnT and CK-MB were more sensitive than H-FABP for the whole group (P = 0.002). In the first group (within 6 h of chest pain) H-FABP positivity was slightly but insignificantly higher in patients with two- and three-vessel disease compared with those with one-vessel disease (60.7% and 33.3%, P = 0.19) and in the same group, patients who underwent primary coronary intervention had a significantly higher H-FABP positivity than others (80%, 32%, P = 0.02). Within 6–24 h of chest pain, H-FABP positivity was 80% in patients with one-vessel disease and 71.4% in patients with two- and three-vessel disease (P = 0.69). Within 6–24 h, positivity of H-FABP reached a peak value of 100% in patients who underwent primary coronary intervention, while H-FABP was positive in 60% of the others (P < 0.001). We conclude that within the 6 h of acute coronary syndrome, H-FABP seems to be a more sensitive biochemical marker than TnT in the early detection of ischemic myocardial necrosis. But after the first 6 h of the onset of chest pain the sensitivity of H-FABP decreases, and this marker should not be used alone in patients admitted 24 h after the onset of chest pain.

Multiple coronary thrombosis and stent implantation to the subtotally occluded right renal artery in a patient with essential thrombocytosis: a case report with review.

Essential thrombocytosis is a myeloproliferative disorder of unknown etiology manifested clinically by the overproduction of platelets in the absence of a definable cause. Platelet dysfunction in essential thrombocytosis results in both hemorrhage and thrombosis. It is one of the rare causes of ischemic cardiovascular events. Fewer than 20 cases of essential thrombocytosis with involvement of coronary arteries leading to acute coronary syndromes or myocardial infarction have been reported. We report a case of multiple coronary thrombosis involving the left anterior descending artery and circumflex artery and stent implantation to the subtotally stenotic right renal artery in a women with unstable angina pectoris, essential thrombocytosis and previous history of renal artery trombosis.

Left ventricular geometric patterns and QT dispersion in untreated essential hypertension.

The spectrum of left ventricular adaptation to hypertension, different types of hypertrophy patterns, and QT dispersion in different types of hypertrophy was investigated in 107 patients with untreated essential hypertension and 30 age- and gender-matched normal adults studied by 12-derivation electrocardiogram (ECG), two-dimensional, and M-mode echocardiography. Left ventricular mass (LVM), body mass index, total peripheral resistance (TPR), relative wall thickness (RWT), and QT dispersion were found to be statistically significantly higher in the hypertension group (P < .001 for all). Among hypertensive patients, 41.1% had both normal LVM and RWT, here called normal left ventricle in hypertension; 10.3% had concentric hypertrophy with increased LVM and RWT; 14.95% had eccentric hypertrophy with increased LVM and normal RWT; and 32.7% had concentric remodeling with normal LVM and increased RWT. Echocardiographically derived cardiac index was higher in the concentric hypertrophy and eccentric hypertrophy patterns (P = .002 and P < .0001, respectively), whereas TPR was higher in the concentric hypertrophy and concentric remodeling patterns (P = .017 and .02, respectively). QT dispersion values were found to be increased in the hypertensive group (P = .001), whereas similar values were calculated for different types of hypertrophy patterns. We conclude that the more common types of ventricular adaptation to essential hypertension are eccentric hypertrophy and concentric remodeling. Concentric hypertrophy is found to be associated with both volume and pressure overload, whereas eccentric hypertrophy is associated with volume overload only and concentric remodeling is associated with pressure overload. But different left ventricular geometric patterns seem to have similar effects on QT dispersion.

Investigation of early atherosclerotic changes in acromegalic patients

Background:  Functional and morphological changes of endothelium were risk factors for mortality attributed to atherosclerosis. Studies investigating early atherosclerotic alterations and the effect of the treatment of acromegaly on these alterations gave conflicting results.

Aspirin-resistant platelet aggregation in a cohort of patients with coronary heart disease.

Aspirin resistance could be defined as thrombotic and embolic cardiovascular events despite regular aspirin therapy. The study aimed to determine the profile and prevalence of aspirin resistance in coronary artery disease patients. We evaluated the prevalence of aspirin resistance in a cohort of 505 patients with the diagnosis of coronary artery disease taking 80–300 mg regular aspirin daily. Platelet functions were analyzed by the Platelet Function Analyzer (PFA)-100 with collagen and epinephrine cartridges and collagen and ADP cartridges. A closure time of 186 s or less with the collagen and epinephrine cartridge was defined as aspirin resistance. Of the patients, 118 (23.4%) were aspirin resistant by the PFA-100. Aspirin-resistant patients were more likely to be older than aspirin-sensitive patients (P = 0.024). No statistically significant differences between the aspirin-resistant and aspirin-sensitive individuals were present in gender, major risk factors of coronary artery disease, number and localization of involved coronary vessels, serum lipid levels, and blood counts. According to the high prevalence of coronary heart disease, many people are affected by aspirin resistance, which may play a role in adverse cardiovascular events. Monitoring of platelet function in patients with coronary heart disease may support the optimization of antiplatelet therapy with additional and/or alternative agents.