1,721,072 research outputs found
Pulmonary Hypertension
No full textPulmonary hypertension (PH) is a haemodynamic and pathophysiological state that can be found in multiple clinical conditions which have been classified into six diagnostic groups with specific histological, clinical and therapeutic features.Despite possible comparable elevations of pulmonary pressure in the different clinical groups, the different clinical groups, the underlying mechanisms, the diagnostic approaches, and the prognostic and therapeutic implications are completely different
The new postgraduate course in heart failure (PCHF): update on 1st PCHF and announcement of the 2nd PCHF. A project of the European Society of Cardiology Heart Failure Association, the ESC European Heart Academy, the Zurich Heart House and the University of Zurich
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Low density lipoprotein cholesterol and coronary microvascular dysfunction in hypercholesterolemia
No full textOBJECTIVES The present study evaluates the impact of total cholesterol (TC) and its subfractions on coronary flow reserve (CFR), an index of the integrated function of the coronary circulation, in asymptomatic subjects. BACKGROUND Endothelial dysfunction of the coronary microcirculation has been reported in asymptomatic subjects with hypercholesterolemia. METHODS Using oxygen-15-labeled water and positron emission tomography, myocardial blood flow (MBF, in ml/min per g) was measured at rest and during intravenous adenosine (140 mu g/kg body weight per min) in 80 asymptomatic nonsmoking men: group 1 (n = 61; age 45 +/- 7 years) had normal TC (less than or equal to 6.5 mmol/liter or less than or equal to 250 mg/dl) and group 2 (n = 19; age 48 +/- 10 years) had elevated TC. RESULTS Total cholesterol were 5.1 +/- 0.8 and 7.2 +/- 0.7 mmol/liter in groups 1 and 2 (p < 0.0005), respectively; low density lipoprotein (LDL) cholesterol levels were 3.2 +/- 0.8 and 4.9 +/- 0.7 mmol/liter (p < 0.0005); high density lipoprotein (HDL) cholesterol levels were 1.1 +/- 0.3 and 1.0 +/- 0.4 mmol/liter (p = NS); and triglyceride levels were 1.8 +/- 1.3 and 3.0 +/- 1.8 mmol/liter (p < 0.005). Groups 1 and 2 did not differ with regard to MBF at rest (0.87 +/- 0.14 vs. 0.84 +/- 0.14), MBF during adenosine (3.63 +/- 1.02 vs. 3.30 +/- 0.86) or CFR (4.23 +/- 1.29 vs. 3.95 +/- 0.93). A significant but weak correlation was found between CFR and HDL in group 1 (r = 0.29, p < 0.05), but not in group 2. In contrast, a significant inverse correlation between LDL and CFR was found in group 2 (r = -0.61, p < 0.05), but not in group 1. CONCLUSION Low density lipoprotein cholesterol but not TC correlated inversely with CFR in hypercholesterolemic subjects. Thus, LDL-induced coronary microvascular dysfunction could play an important role in the pathogenesis of coronary artery disease and its complications. (J Am Coil Cardiol 2000;36:103-9) (C) 2000 by the American College of Cardiology
Tetrahydrobiopterin restores impaired coronary microvascular dysfunction in hypercholesterolaemia
No full textPurpose: Tetrahydrobiopterin (BH4) is an essential co-factor for the synthesis of nitric oxide (NO), and BH4 deficiency may cause impaired NO synthase (NOS) activity. We studied whether BH4 deficiency contributes to the coronary microcirculatory dysfunction observed in patients with hypercholesterolaemia. Methods: Myocardial blood flow (MBF; ml min(-1) g(-1)) was measured at rest, during adenosine-induced (140 mug kg(-1) min(-1) over 7 min) hyperaemia (mainly non-endothelium dependent) and immediately after supine bicycle exercise (endothelium-dependent) stress in ten healthy volunteers and in nine hypercholesterolaemic subjects using O-15-labelled water and positron emission tomography. Measurements were repeated 60 min later, after intravenous infusion of BH4 (10 mg k(g)-(1) body weight over 30 min). Adenosine-induced hyperaemic MBF is considered to represent (near) maximal flow. Flow reserve utilisation was calculated as the ratio of exercise-induced to adenosine-induced hyperaemic MBF and expressed as percent to indicate how much of the maximal (adenosine-induced) hyperaemia can be achieved by bicycle stress. Results: BH4 increased exercise-induced hyperaemia in controls (2.96 +/- 0.58 vs 3.41 +/- 0.73 ml min(-1) g(-1), p<0.05) and hypercholesterolaemic subjects (2.47 +/- 0.78 vs 2.70 +/- 0.72 ml min(-1) g(-1), p<0.01) but had no influence on MBF at rest or during adenosine-induced hyperaemia in controls (4.52 +/- 1.10 vs 4.85 +/- 0.45 ml min(-1) g(-1), p=NS) or hypercholesterolaemic subjects (4.86 +/- 1.18 vs 4.53 +/- 0.93 ml min(-1) g(-1), p=NS). Flow reserve utilisation remained unchanged in controls (70 +/- 17% vs 71 +/- 19%, p=NS) but increased significantly in hypercholesterolaemic subjects (53 +/- 15% vs 66 +/- 14%, p<0.05). Conclusion: BH4 restores flow reserve utilisation of the coronary microcirculation in hypercholesterolaemic subjects, suggesting that BH4 deficiency may contribute to coronary microcirculatory dysfunction in hypercholesterolaemia
Coronary heart disease in smokers - Vitamin C restores coronary microcirculatory function
No full textBackground-Coronary endothelial function and vasomotion are impaired in smokers without coronary disease, and this is thought to be due to increased oxidative stress. Methods and Results-We used positron emission tomography to measure the coronary flow reserve, an integrated measure of coronary flow, through both the large epicardial coronary arteries and the microcirculation in 11 smokers and 8 control subjects before and after administration of the antioxidant vitamin C, At baseline, coronary flow reserve was reduced by 21% in smokers compared with control subjects (P < 0.05) but was normalized after vitamin C, whereas the drug had no effect in control subjects. Conclusions-The present study is the first to demonstrate that the noxious prooxidant effects of smoking extend beyond the epicardial arteries to the coronary microcirculation and affect the regulation of myocardial blood flow. Vitamin C restores coronary microcirculatory responsiveness and impaired coronary flow reserve in smokers, which provides evidence that the damaging effect of smoking is at least in part accounted for by an increased oxidative stress
N-terminal pro-B-type natriuretic peptide-ratio predicts mortality after transcatheter aortic valve replacement
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