Effect of Cigarette Smoking on Platelet Aggregation

Background: Cigarette smoking may increase platelet aggregation and cause atherothrombotic cardiovascular events. We aimed to investigate the impact of cigarette smoking on platelet function in patients with ischemic coronary heart disease (CHD).Methods: Twenty patients with ischemic stable CHD under aspirin therapy (300 mg/d), who continue to smoking despite all warnings, and 20 nonsmokers with CHD are enrolled in the study. Platelet function is studied at the morning, before and 15 minutes after the first cigarette, by the Platelet Function Analyzer (PFA)-100, with collagen and epinephrine and collagen and adenosine diphosphate cartridges. Post aspirin platelet hyperactivity is defined as having a closure time (CT) shorter than 186 seconds despite regular aspirin intake. Serial CT measurements are analyzed by paired samples t test.Results: Persistent platelet activity was present in 4 smoker (20%) and 3 nonsmoker (15%) patients at the beginning. Platelet activity measured by the PFA-100 is been increased significantly after cigarette smoking ( P = .004). Shorter CTs were determined after smoking in all patients with and without baseline persistent platelet activity, and 4 more participants became aspirin nonresponder ( P = .004). No significant differences in demographic, hematological, and biochemical parameters were determined between aspirin responders and nonresponders.Conclusions: We determined that cigarette smoking may increase platelet aggregation in patients with ischemic CHD in an aspirin nonresponsive manner. Our results emphasize the importance of quitting cigarette smoking in patients with CHD.

Folic Acid and vitamin B12 supplementation improves coronary flow reserve in elderly subjects with vitamin B12 deficiency

BACKGROUND AND AIMS

Major cardiovascular risk factors including hyperhomocysteinemia are frequently associated with decreased coronary flow reserve (CFR), an important physiological parameter of the coronary circulation. This study was designed to determine whether folate (5 mg) and vitamin B12 (500 μg) supplementation in elderly patients with vitamin B12 deficiency improved CFR, while reducing homocysteine levels.

METHODS

Forty-four patients aged >65 years showing serum vitamin B12 concentrations <180 mg/dL were randomized to take either oral folate (5 mg) plus vitamin B12 (500 μg) supplementation (n = 24) or placebo (n = 20) for 8 weeks. The study course consisted of two visits: visit 1 (pretreatment) included the baseline assessment of laboratory profile and CFR values with trans-thoracic Doppler echocardiography. Visit 2 was scheduled 8 weeks later to repeat CFR and laboratory tests after therapy.

RESULTS

In the treatment arm, oral supplementation with folate and vitamin B12 significantly improved total cholesterol, serum folate, serum vitamin B12, homocysteine, and insulin resistance. At 8 weeks, the treatment group had a significant increase from baseline in CFR values (baseline: 1.7 ± 0.2; postttreatment: 2.1 ± 0.2, p <0.001) that was not seen in the placebo group (baseline: 1.6 ± 0.2; posttreatment: 1.6 ± 0.2; P = ns).

CONCLUSIONS

In this study of elderly subjects with vitamin B12 deficiency, supplementation with folate and vitamin B12 was associated with a significant improvement in CFR values.

Coronary artery calcification and coronary flow velocity in haemodialysis patients

BACKGROUND

Decreased coronary flow reserve (CFR) is a marker of endothelial dysfunction, coronary artery calcification and inflammation, well-known cardiovascular risk factors in haemodialysis (HD) patients. In this study, we aimed to investigate the correlation of coronary artery calcification scores (CACS) with CFR in HD patients.

METHODS

Sixty-four end-stage renal failure patients were enrolled in this study (38 males, 26 females). Thirty-nine healthy subjects (22 males, 17 females) were included in the control group. Biochemical parameters and acute-phase inflammation marker [high-sensitivity C-reactive protein (hs-CRP)] of patients were recorded before dialysis. The CACS were measured by electron beam computerized tomography method. CFR recordings were performed by trans-thoracic Doppler echocardiography. The relationship between CACS and CFR was evaluated.

RESULTS

The mean CACS was 281 +/- 589 and 29 patients had CACS < 10. Patients with CACS > 10 had significantly lower CFR values compared to patients with CACS < 10 (1.56 +/- 0.38 vs 1.84 +/- 0.53, P = 0.024). However, there was no difference in hs-CRP values between the groups. CFR was negatively correlated with CACS (r = -0.276, P = 0.030). In multiple stepwise regression analysis, CACS was found to be an independent variable for predicting CFR (P = 0.048). During a follow-up of 18 months, 10 patients had experience of cardiovascular events. Patients with CACS > 10 had significantly higher event rate [34.5% (10/29) vs 0% (0/24)] compared to those with CACS < 10 (P = 0.001). Patients who developed cardiovascular events had significantly higher mean CACS and lower CFR values than the remaining group (P = 0.019 and P = 0.039). All of four patients who died during follow-up were in the CFR < 2 and CACS > 10 groups.

CONCLUSIONS

CACS was associated with CFR in HD patients. However, we did not find any association of inflammation with CACS and CFR. This association between CFR and CACS might indicate two different (anatomical and functional) aspects of the common pathophysiology of the arterial system in HD patients.

Coronary flow reserve is impaired in patients with nonalcoholic fatty liver disease: association with liver fibrosis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of cardiovascular disease. Coronary flow reserve (CFR) is widely used to examine the integrity of coronary microvascular circulation. We evaluated the prevalence of impaired CFR in patients with biopsy-proven NAFLD. We also investigated the independent clinical, biochemical, and liver histology predictors of CFR in the setting of NAFLD.

METHODS

Fifty-nine consecutive patients with NAFLD and 77 age- and gender-matched controls were evaluated. CFR recordings were performed by transthoracic Doppler harmonic echocardiography. CFR>or=2.0 was considered normal.

RESULTS

CFR was significantly lower in patients with NAFLD than in controls (2.11+/-0.45 vs. 2.52+/-0.62, P<0.001). An impaired CFR (i.e. <2) was found in 25 NAFLD patients (42.4%) whereas all controls had normal CFR values (P<0.001). A stepwise linear regression analysis in NAFLD patients identified liver fibrosis scores as the only independent predictor of CFR values (beta=-0.60; t=-2.44, P=0.021).

CONCLUSION

Our findings indicate that in patients with biopsy-proven NAFLD: (a) an abnormal CFR is found in approximately 42.4% of cases, and (b) liver fibrosis scores are an independent predictor of depressed CFR.

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.

OBJECTIVE

Surrogate markers of early atherosclerotic changes, i.e. brachial artery flow-mediated dilation (FMD) and carotid artery intima-media-thickness (IMT) in active and inactive acromegalic patients were compared with control subjects matched to patients for age, sex and cardiovascular risk factors to find out the direct effects of growth hormone (GH)/insulin-like growth factor-1 excess.

METHODS

In 14 active acromegalics and their 14 matched controls, 14 inactive acromegalics and their 14 matched controls, carotid artery IMT and FMD of brachial artery were measured. Inactive acromegalics were in remission for at least 1 year.

RESULTS

Active acromegalics had higher IMT than matched controls and inactive acromegalics (0.85 +/- 0.20 mm, 0.64 +/- 1.77 mm, 0.66 +/- 0.20 mm respectively; p < 0.005, p < 0.05) and IMT of inactive acromegalics was not different from their matched controls (0.61 +/- 0.12 mm). FMD was significantly lower in active acromegalics than in matched controls and inactive acromegalics (2.910 +/- 2.00 mm, 6.5 +/- 2.81 mm, 5.68 +/- 2.9 mm respectively; p < 0.005, p < 0.05). FMD of inactive acromegalics was not significantly different from their matched controls (7.96 +/- 3.12 mm). A significant inverse relationship was found between GH and FMD in active acromegalics (r = -0.659, p = 0.010).

CONCLUSION

In active acromegalics, early atherosclerotic changes are not only attributed to the high prevalence of risk factors, but also to the abnormal GH secretion itself.

Left ventricular function by 'conventional' and 'tissue Doppler' echocardiography in paediatric dialysis patients

AIM

Cardiovascular abnormalities are common in children with chronic kidney disease (CKD). Left ventricular (LV) structure and functions have been extensively studied by conventional pulse-wave Doppler echocardiography (cPWD), however, tissue Doppler imaging (TDI) is a relatively new echocardiography method. The aims of this study were to evaluate LV diastolic function in paediatric dialysis patients using cPWD and TDI methods, and to compare the findings obtained with two modalities.

METHODS

This study included 38 children and adolescents on dialysis (14 haemodialysis and 24 peritoneal dialysis, duration of dialysis 58.0 +/- 32.8 months) and 16 age- and sex-matched healthy subjects.

RESULTS

The mean left ventricular mass index (LVMI) was significantly higher in the patient group (P < 0.001) and the most common cardiac geometry was concentric LV hypertrophy (55%). There was no significant difference in LV systolic function between patient and control groups. However, dialysis patients had worse LV diastolic function both according to cPWD (lower E/A ratio) and TDI (lower Em/Am ratio) than the healthy subjects (P < 0.001 and P = 0.001, respectively). Also, the index of LV filling pressure (E/Em ratio) obtained by the combination of cPWD and TDI was significantly higher in the patients (P < 0.001). Cumulative dose of calcium-based phosphate binder (CBPB), diastolic blood pressure and LVMI were the independent predictors of E/Em ratio.

CONCLUSION

Our study shows that LV diastolic dysfunction is common in paediatric dialysis patients and TDI findings correlate well with cPWD findings. Similarly, higher dose intake of CBPB, hypertension and LV hypertrophy have a negative effect on LV filling pressure suggesting diastolic function.

Endothelial function and endothelial nitric oxide synthase intron 4a/b polymorphism in primary hyperparathyroidism

BACKGROUND AND AIM

Patients with symptomatic primary hyperparathyroidism (pHT) have increased cardiovascular morbidity and mortality. Endothelial nitric oxide synthase (eNOS) intron 4a/b polymorphism is associated with coronary artery disease and hypertension in various populations. Our aim is to evaluate endothelial function in patients with pHT during pre-operative hypercalcemic and post-operative normocalcemic periods and to determine whether intron 4a/b polymorphism of eNOS gene influences endothelial function.

SUBJECTS AND METHODS

Forty patients with pHT (age 48.48+/-11.64 yr) were examined pre-operatively and reexamined 5.8+/-1.9 months after parathyroidectomy. Forty-three healthy subjects (age 47.13+/-8.14 yr) were served as control group. Endothelial function was determined by flow-mediated dilation of brachial artery (FMD). eNOS4a/b polymorphism was detected by polymerase chain reaction.

RESULTS

FMD was significantly lower in patients pre-operatively compared with controls (8.48+/-1.78% vs 19.49+/-2.34%, p<0.001). FMD improved significantly after parathyroidectomy (16.19+/-2.16%, p<0.001 compared with pre-operative measurements), but was still significantly lower than controls (p<0.001). The distribution of eNOS4a/b genotype frequencies was not significantly different between patients and controls. Logistic regression analysis showed that increased serum calcium (>2.47 mmol/l) and PTH concentrations (>7.75 pmol/l) were significant independent predictors of lower FMD (<16.7%). ENOS4a/b polymorphism did not enter in this model.

CONCLUSION

Impaired endothelial function in patients with pHT improves after successful parathyroid surgery. No compelling data are evident to suggest that eNOS4a/b polymorphism modifies the endothelial function in patients with pHT.

Coronary flow reserve dysfunction in hemodialysis and kidney transplant patients

BACKGROUND

The assessment of coronary flow reserve (CFR) by trans-thoracic echocardiography has recently been introduced into clinical studies. Impairment of coronary microvascular functions and decreased CFR detected by trans-thoracic Doppler harmonic echocardiography (TTDE) has recently been reported in hemodialysis (HD) patients, but there is no comparative study between HD patients and renal transplant recipients.

METHODS

The aim of our study was to evaluate coronary microvascular circulation in chronic HD patients and renal transplant recipients. Forty-eight chronic HD patients, 27 renal transplant patients and 39 normotensive healthy controls were studied for the assessment of CFR by TTDE. The carotid artery intima media thickness (IMT) and areas of focal plaque formation were also evaluated in all subjects.

RESULTS

CFR values were significantly lower in both the HD and renal transplant groups than in the control group (p = 0.00). CFR values (1.57 +/- 0.32 vs. 1.89 +/- 0.50, p = 0.01) were also significantly lower in the HD group than in the renal transplant group. In 43 of 48 (89.6%) HD patients, CFR was <2.0; however, in 16 of 27 (59.3%) renal transplant recipients it was <2.0 (p = 0.00). When the HD and renal transplant groups were divided into two subgroups, according to CFR measurements (CFR < 2 and > or =2), no significant differences were found with respect to coronary risk factors and left ventricular echocardiographic measurements. The IMT of the control group (0.586 +/- 0.163 mm) was significantly lower than the HD (0.799 +/- 0.218 mm) and renal transplant groups (0.681 +/- 0.148 mm; p = 0.00). The IMT of the HD patients (0.799 +/- 0.218 mm) was significantly higher than the renal transplant recipients (0.681 +/- 0.148 mm; p = 0.01).

CONCLUSIONS

Renal transplant and HD patients had lower CFR values detected by TTDE, which may be regarded as an early finding of an affected cardiovascular system. CFR is more impaired in HD patients than renal transplant recipients. Uremia-associated microvascular disease may be responsible for CFR impairment in HD patients.

Reduced coronary flow reserve and early diastolic filling abnormalities in patients with nephrotic syndrome

BACKGROUND

Increased cardiovascular disease risk is very well known in nephrotic syndrome. Coronary flow reserve measurement by trans-thoracic echocardiography reflects coronary microvascular and endothelial function. However, diastolic filling abnormalities by echocardiography may indicate diastolic dysfunction. Our aim was to evaluate endothelial and diastolic functions by trans-thoracic echocardiography in nephrotic syndrome.

METHODS

Eighteen patients with nephrotic syndrome (five females, 34 +/- 17 years) and 30 controls (10 females, 35 +/- 10 years) were evaluated in this cross-sectional observational study. Age, weight, lipid profile, glucose, blood urea nitrogen, creatinine, serum albumin, total protein, C-reactive protein, erythrocyte sedimentation rate, blood pressures, 24-hour urine volume, and protein were recorded. Glomerular filtration rate was estimated by Cockcroft-Gault Formula. Doppler flow and other echocardiographic parameters were measured by Vivid 7 echocardiography.

RESULTS

Coronary flow reserve was significantly lower in patients than controls (p < 0.001) and was negatively correlated with proteinuria (p < 0. 001), creatinine levels (p = 0.03), total cholesterol (p = 0.02), C-reactive protein (p = 0.02), and erythrocyte sedimentation rate (p = 0.005). E/A ratio was significantly lower in patients than in controls (p = 0.005). DT was significantly higher in patients than in controls (p = 0.01) and isovolumic relaxation time was similar in both groups.

CONCLUSION

Coronary flow reserve and left ventricular diastolic filling are significantly impaired in nephrotic syndrome. Proteinuria, serum creatinine, total cholesterol and inflammation may have all contributory effects on endothelial dysfunction. Early evaluation of patients with nephrotic syndrome should include coronary flow and diastolic function by echocardiography.

Coronary artery bypass grafting in a 12-year-old girl with familial hypercholesterolemia

We present the case of a 12-year-old girl with familial hypercholesterolemia and coronary artery disease. She underwent triple-vessel coronary artery bypass grafting with bilateral pedicled internal mammary artery grafting without adverse events. Pediatric patients with familial hypercholesterolemia may present with premature coronary atherosclerosis requiring coronary artery bypass grafting. In situ internal mammary artery grafts should be the graft of choice.

The trivest in overreaching syndrome: Cardiac fatigue, muscular weakness, and vascular dysfunction

Although the underlying mechanisms responsible for cardiac dysfunction after prolonged exercise remains to be elucidated, it has reported cardiac deterioration following exhaustive exercise in the absence of underlying cardiovascular diseases, which has been attributed to cardiac fatigue. The objective of this study was to evaluate cardiac functions, exercise capacity, and flow-mediated dilatation in overreaching syndrome. We studied 13 male marathon runners who took part in a marathon. Cardiopulmonary exercise testing, transthoracic echocardiography and endothelium-dependent vasodilatation of the brachial artery were performed at before- and after-race. Peak oxygen consumption, left ventricular tissue Doppler imaging parameters and flow-mediated dilatation were decreased after-race values compared with before-race values. Overreaching syndrome could arise involves a physio-pathological trivest, cardio-vasculo-muscular axis, which include three vicious cycles.

Endothelial nitric oxide synthase intron 4a/b polymorphism and early atherosclerotic changes in hypopituitary GH-deficient adult patients

OBJECTIVE

Endothelial nitric oxide synthase (eNOS) intron 4a/b polymorphism is associated with plasma NO concentrations and coronary artery disease/hypertension in various populations. GH deficiency in adulthood predisposes to reduced NO concentrations and premature atherosclerosis. Our aim was to determine whether intron 4a/b polymorphism of eNOS gene influences endothelial function and early atherosclerotic changes in GH-deficient hypopituitary patients.

DESIGN

Thirty-three hypopituitary GH-deficient patients on conventional replacement therapy other than GH and 43 age-, sex-, and body mass index (BMI)-matched controls were studied in this cross-sectional case-control study.

METHODS

Early atherosclerotic changes were determined by flow-mediated dilation (FMD) of brachial artery and carotid artery intima-media thickness (IMT). eNOS4a/b polymorphism was detected by PCR.

RESULTS

Hypopituitary patients had significantly higher total/low-density lipoprotein cholesterol and fat mass and lower IGF-I concentrations compared with controls. IMT was significantly higher in patients (0.777+/-0.23 vs 0.639+/-0.17 mm, P<0.01). No significant difference was observed with respect to FMD measurements. eNOS4a/b genotype frequencies were similar between patients and controls. Patients carrying 'a' allele (a/a and a/b) had significantly higher IMT compared with controls carrying 'a' allele and bb genotype (P<0.05). However, logistic regression analysis revealed that presence of hypopituitarism, age> or =45 years, and BMI> or =27.9 kg/m(2) were significant independent predictors of IMT> or =0.65 mm.

CONCLUSION

No compelling data are evident to suggest that eNOS4a/b polymorphism modifies the atherosclerotic process in GH-deficient situations. A large case-control study is needed to confirm our findings.

Coronary flow velocity reserve and carotid intima media thickness in patients with autosomal dominant polycystic kidney disease: from impaired tubules to impaired carotid and coronary arteries

BACKGROUND AND OBJECTIVES

Cardiovascular problems are a major cause of morbidity and mortality in patients with autosomal dominant polycystic kidney disease. Endothelial dysfunction, an early and reversible feature in the pathogenesis of atherosclerosis, is associated with increased vascular smooth muscle tone, arterial stiffening, and increased intima-media thickness. Coronary flow velocity reserve is a noninvasive test showing endothelial function of epicardial coronary arteries and coronary microcirculatory function. The aim of the study was to investigate the carotid intima-media thickness and coronary flow velocity reserve in patients with autosomal dominant polycystic kidney disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Thirty normotensive patients with autosomal dominant polycystic kidney disease (10 male, 20 female) with well-preserved renal function and 30 healthy subjects (12 male, 18 female) were included in the study. Coronary flow velocity reserve was measured at baseline and after dipyridamole infusion by echocardiography. Coronary flow velocity reserve was calculated as the ratio of hyperemic to baseline diastolic peak velocities.

RESULTS

Carotid intima-media thickness was significantly higher in patients than in control subjects (0.80 +/- 0.29 versus 0.54 +/- 0.14 mm, respectively; P < 0.001). Moreover, coronary flow velocity reserve was significantly lower in patients than in control subjects (1.84 +/- 0.39 versus 2.65 +/- 0.68, respectively; P < 0.001).

CONCLUSIONS

Normotensive patients with autosomal dominant polycystic kidney disease with well-preserved renal function have significantly increased carotid intima-media thickness and significantly decreased coronary flow velocity reserve compared with healthy subjects. These findings suggest that atherosclerosis starts at an early stage in the course of their disease in patients with autosomal dominant polycystic kidney disease.

Effects of different intensities of acute exercise on flow-mediated dilatation in patients with coronary heart disease

It is known that regular exercise training improves endothelial dysfunction in coronary artery disease, but, little is known concerning different intensities of acute exercise on endothelial function. We evaluated anaerobic threshold and peak oxygen uptake level of acute exercise on flow-mediated dilatation in patients with stable coronary artery disease. Endothelium-independent vasoreactivity in patients showed a trend with increase at threshold level exercise; however, it was significantly decreased at peak level exercise. Moderate intensity exercise (nearly anaerobic threshold level) should be recommended a therapeutic and preventative strategy for starting of cardiac rehabilitation program in patients with coronary artery disease.

Androgenic anabolic steroids also impair right ventricular function

Chronic anabolic steroid use suppresses left ventricular functions. However, there is no information regarding the chronic effects of anabolic steroids on right ventricular function which also plays a key role in global cardiac function. The main objective of the present study was to investigate the effects of androgenic anabolic steroids usage among athletes on remodeling the right part of the heart. Androgenic-anabolic steroids-using bodybuilders had smaller diastolic velocities of both ventricles than drug-free bodybuilders and sedentary counterparts. This study shows that androgenic anabolic steroids-using bodybuilders exhibited depressed diastolic functions of both ventricles.

Coronary flow reserve after L-thyroxine therapy in Hashimoto's thyroiditis patients with subclinical and overt hypothyroidism

BACKGROUND/AIMS

Overt and subclinical hypothyroidism are reported to be associated with increased cardiovascular disease risk. We have used coronary flow reserve (CFR) measurement by trans-thoracic Doppler echocardiography (TTDE) to determine coronary microvascular function in Hashimoto's thyroiditis patients with overt and subclinical hypothyroidism and to evaluate effects of L-thyroxine replacement on coronary endothelial function.

METHODS

In total, 10 overt hypothyroid patients, 10 subclinical hypothyroid patients, and 10 controls were enrolled. FT4, TSH, anti-thyroid antibodies, lipid profile, insulin, glucose, HOMA-IR, physical parameters, and CFR measured by TTDE were recorded before and after 6 months of L: -thyroxine replacement in all groups.

RESULTS

CFR values of all hypothyroid patients at baseline were significantly lower than those in controls. After L: -thyroxine, CFR increased significantly in overt and subclinical hypothyroidism with respect to the baseline measurements (P < 0.05). When baseline and second measurements were evaluated collectively for patients and controls, CFR was positively correlated with FT4 levels (r = 0.31, P = 0.01) and negatively correlated with TSH and HOMA-IR (r = -0.38, P = 0.002 and r = -0.42, P < 0.001, respectively).

CONCLUSION

Subclinical as well as overt hypothyroid patients have impaired coronary microvascular function which improved after L: -thyroxine therapy. Treatment of Hashimoto's thyroiditis patients with subclinical hypothyroidism should be considered to improve cardiovascular disease risk.

Effect of high dose statin therapy on platelet function; statins reduce aspirin-resistant platelet aggregation in patients with coronary heart disease

BACKGROUND

Current evidence supports the preventive role of statins on platelet aggregation in patients with coronary heart disease.

AIM

Our aim was to determine the effects of aggressive statin therapy on platelet function in patients with coronary heart disease.

MATERIAL AND METHODS

A total of 178 consecutive patients (37-68 years old, 35.9% women) with stable coronary artery disease (CAD) was enrolled in the study. Platelet function assays were realized by the Platelet Function Analyzer (PFA)-100 with collagen and epinephrine (Col/Epi) and collagen and ADP (Col/ADP) cartridges. Aspirin resistance was defined as having a closure time (CT) of <186 s with Col/Epi cartridges despite regular aspirin therapy. A statin therapy protocol applied to the patients with aspirin resistance for 3 months.

RESULTS

We determined that 20 (11.2%) of patients had aspirin resistance by the PFA-100. Mean closure time measured with the Col/ADP cartridges was 83 +/- 18 s (53-162 s). Of the patients 12 were not on a statin therapy and eight were taking 10 mg daily atorvastatin. After 3 months of 40 mg daily atorvastatin therapy 13 subjects with aspirin resistance became aspirin sensitive by PFA-100 (P < 0.0001). There was also a significant decrease in total and LDL cholesterol levels and an increase in HDL cholesterol at the third month of statin therapy (P < 0.0001 for all).

CONCLUSION

Statin therapy reduced the in vitro aspirin resistance in 65% of the patients after a therapy of 3 months. Further studies are needed to elucidate the mechanism of statins' effects on platelet reactivity.

Coronary flow reserve is also impaired in patients with subclinical hypothyroidism

The diagnosis of subclinical hypothyroidism and detection of its effects on cardiovascular system is important. Also, the patients with subclinical hypothyroidism even at the very early stage are at increased risk for developing atherosclerosis. We evaluated coronary microvascular circulation and endothelial dysfunction of epicardial coronary arteries by the measurement of coronary flow velocity reserve via a non invasive technique, transthoracic Doppler echocardiography in subclinical hypothyroidism. Coronary flow reserve in patients with subclinical hypothyroidism such as in overt hypothyroidism was lower than that of euthyroid subject. As a conclusion, endothelial and microvascular dysfunction, which are early harbingers of atherosclerosis, are shown in overt and subclinical hypothyroidism.

Acute effects of smoking on coronary flow velocity reserve and ventricular diastolic functions

Although it is well known that chronic effect of smoking on cardiovascular system, relation between coronary vascular reactivity and ventricular functions after acute smoking has not been well understood. The purpose of this study was to assess the relation between coronary flow velocity reserve and ventricular diastolic functions measured by tissue Doppler imaging after acute smoking. We found that coronary flow velocity and diastolic functions of right ventricle were decreased. Also, there was a correlation between coronary flow velocity reserve and diastolic ratio of the ventricle. Acute smoking may affect diastolic functions of the ventricles, especially right ventricle via changes of coronary flow.