Corrigendum for health-related quality of life and hospitalizations in chronic thromboembolic pulmonary hypertension versus idiopathic pulmonary arterial hypertension: And analysis from the Pulmonary Hypertension Association Registry.

[This corrects the article DOI: 10.1177/20458940211053196.].

Survival in pulmonary arterial hypertension: a reappraisal of the NIH risk stratification equation.

The aim of the present study was to determine contemporary survival in pulmonary arterial hypertension (PAH), and to investigate whether or not the National Institutes of Health (NIH) equation remains an accurate predictor of survival. In 576 patients with PAH referred during 1991-2007, observed survival was described using the Kaplan-Meier method. In patients with idiopathic, familial and anorexigen-associated PAH (n = 247), observed versus NIH equation predicted survival was compared. A new survival prediction equation was developed using exponential regression analysis. The observed 1-, 3- and 5-yr survival in the total cohort were 86, 69 and 61%, respectively. In patients with idiopathic, familial and anorexigen-associated PAH, the observed 1-, 3- and 5-yr survival (92, 75 and 66%, respectively) were significantly higher than the predicted survival (65, 43 and 32%, respectively). The new equation (P(t) = e(-A(x,y,z)t), where P(t) is probability of survival, t the time interval in years, A(x,y,z) = e((-1.270-0.0148x+0.0402y-0.361z)), x the mean pulmonary artery pressure, y the mean right atrial pressure and z the cardiac index) performed well when applied to published contemporary studies of survival in PAH. Contemporary survival in the PAH cohort was better than that predicted by the NIH registry equation. The NIH equation underestimated survival in idiopathic, familial and anorexigen-associated PAH. Once prospectively validated, the new equation may be used to determine prognosis.

Solute-solvent interactions of acid-1,4-dioxane mixtures-By dielectric, FTIR, UV-vis and 13C NMR spectrometric methods.

Results of the dielectric studies carried out on the binary mixture of n-butyric and caprylic acids with 1,4-dioxane over the entire composition range and at temperatures 303K, 308K, 313K and 318K, and FTIR, UV-vis and 13C NMR spectral studies are presented in this paper. The excess permittivity and excess free energy were fitted with the Redlich-Kister polynomial. The variation of Kirkwood correlation factors, excess permittivity and excess free energy of mixing with the concentration and temperature has been investigated in view of understanding the ordering of dipoles of solute and solvent molecules. The FTIR, UV-vis and 13C NMR spectral analysis reveals the formation of complex between solute and solvent molecules. The parallel alignment of electric dipoles of the complex predicted by dielectric studies is well supported by UV-vis spectral analysis. The structure of the complex molecule present in the clusters has been deduced.

A USA-based registry for pulmonary arterial hypertension: 1982-2006.

The aim of this study was to define the epidemiology of World Health Organization (WHO) Group I pulmonary arterial hypertension (PAH) in a large referral centre in the USA. The Pulmonary Hypertension Connection registry, initiated in 2004, evaluated all patients in a single USA practice from 1982-2006. For comparison, the authors divided the group by incident versus prevalent cohorts, aetiology and by treatment era. In total, 578 patients (77% female) aged 48+/-14 yrs were entered. Of these, 80% had class III or IV symptoms. Over time, connective tissue disease-associated PAH increased, while referrals for HIV remained low. One-third of patients were referred on calcium channel blocker therapy even though only 4.6% had an acute response to vasodilator challenge. When compared by treatment era, there were no differences in the severity of PAH. However, survival had improved over time, with a 1-yr survival of 85% in the incident cohort. In the USA, pulmonary arterial hypertension patients are still referred to tertiary centres too late. Referral of connective tissue disease is increasing, while referral of HIV remains low. Inappropriate calcium channel blocker treatment is common. Survival rates have increased but remain low suggesting that prognosis is improving but PAH is still a progressive, fatal disease.