Epidemiology and long-term survival of pulmonary arterial hypertension in the Czech Republic: a retrospective analysis of a nationwide registry

BACKGROUND: Pulmonary arterial hypertension (PAH) is a severe and progressive disease characterized by increased pulmonary vascular resistance, ultimately leading to right heart failure and death. Epidemiological data from national registries are growing worldwide, but are still unavailable in Eastern Europe. METHODS: A PAH registry was initiated in January 2007 using a nationwide network of echocardiographic centers and four diagnostic centers that specialize in PAH. All patients aged above 18 years, diagnosed with PAH and monitored between January 2000 and December 2007 were included. Patients diagnosed with PAH between January and December 2007 were classified as incident. The survival analyses were performed up to the end of 2010. Prognostic factors at the time of diagnosis were identified using uni- and multivariable Cox proportional hazard models. RESULTS: Overall, 191 patients were included (100 prevalent cases, 91 incident cases). Patients were predominantly female (n = 125) and had a mean age of 51.9 ± 16.9 years. Incident patients were significantly older at the time of diagnosis than prevalent patients (p < 0.001). Most patients (60.7%) had idiopathic PAH; 20.4% had PAH associated with congenital heart disease and 11.4% had PAH associated with connective tissue disease. Estimates of prevalence and incidence of PAH in adults were 22.4 cases per million and 10.7 cases per million per year, respectively. The 1-, 2- and 3-year survival rates in the incident PAH cohort were 89% (95% confidence intervals [CI] 83–95%), 78% (95% CI 70–87%) and 74% (95% CI 65–83%), respectively. Lower survival rates were significantly associated with higher age (hazard ratio [HR] 6.6 95% CI 1.4–30.9) and lower creatinine clearance (HR 3.3 95% CI 1.1–9.7). CONCLUSION: This is the first study in Eastern Europe to describe the prevalence, incidence and survival of patients with PAH from a national representative registry. This registry from the Czech Republic highlights that diagnosis of PAH is frequently made late in the disease continuum when patients have significant functional impairment

Strength Analysis of AL-7F-1 Engine Turbine Rotor Blade

The key intent of the article is to describe clearly the strength issue of blades for aircraft engines, on the basis of which to create a calculation algorithm and apply it to a particular blade. The work then deals with a strength analysis of a rotor blade used in the gas turbine of an AL-7F-1 turbocharger aircraft engine. The article describes comprehensively in terms of strength the influences which act on the blade during operation. Generally, these loads can be divided into static load, which includes the tensile stress generated by the rotating mass of the blades, bending and torsion moments caused by the kinetic energy of the flowing gas. The last part of the article is dedicated to the issue of compensation of the bending moments acting on the turbine blades, resulting in analytical calculation of the blade inclination angles in the critical cross section.</jats:p