sildenafil-citrate and Thalassemia

Pulmonary hypertension is a significant complication in thalassemia patients. Recent studies showed that inhaled nebulized nitrite could rapidly decrease pulmonary artery pressure. We conducted a multicenter, randomized, double-blind, placebo-controlled trial in thalassemia patients with symptomatic pulmonary hypertension diagnosed by right heart catheterization. Eleven patients were recruited; five were assigned to the nitrite group and six to the placebo group. Patients were treated with the optimal doses of sildenafil for pulmonary hypertension and randomly assigned into the placebo or nitrite groups. Patients in the nitrite group were given inhaled nebulized 30 mg sodium nitrite twice a day for 12 weeks. The clinical outcomes measured at week 12 were the changes in 6-min walk distance (6MWD), mean pulmonary artery pressure (MPAP), and N-terminal pro B-type natriuretic peptide. The MPAP estimated by echocardiography was significantly reduced from 33.6 ± 7.5 mmHg to 25.8 ± 6.0 mmHg (mean difference = 7.76 ± 3.69 mmHg, p = 0.009 by paired t-test). Furthermore, 6MWD was slightly increased from 382.0 ± 54.0 m to 432 ± 53.9 m (mean difference = 50.0 ± 42.8 m, p = 0.059 by paired t-test) in the nitrite group. At week 12, the nitrite group had lower MPAP than the placebo group (25.8 ± 6.0 vs. 45.7 ± 18.5 mmHg, p = 0.048 by unpaired t-test). No significant difference in 6MWD and N-terminal pro B-type natriuretic peptide between the two groups was observed at week 12. There was no hypotension or other significant adverse effects in the nitrite group.

Topics: Administration, Inhalation; Adult; Blood Pressure; Double-Blind Method; Female; Humans; Hypertension, Pulmonary; Male; Phosphodiesterase Inhibitors; Sildenafil Citrate; Sodium Nitrite; Thalassemia; Young Adult

Pulmonary hypertension is a common but often overlooked complication associated with thalassemia syndromes. There are limited data on the safety and efficacy of selective pulmonary vasodilators in this at-risk population. We, therefore, designed a 12-week, open-label, phase 1/2, pilot-scale, proof-of-principle trial of sildenafil therapy in 10 patients with β-thalassemia and at increased risk of pulmonary hypertension based on an elevated tricuspid regurgitant jet velocity >2.5 m/s on Doppler-echocardiography. Variables compared at baseline and after 12 weeks of sildenafil treatment included Doppler-echocardiographic parameters, 6-minute walked distance, Borg Dyspnea Score, New York Heart Association functional class, pulmonary function, and laboratory parameters. Treatment with sildenafil resulted in a significant decrease in tricuspid regurgitant jet velocity by 13.3% (3.0±0.7 versus 2.6±0.5 m/s, P=0.04), improved left ventricular end systolic/diastolic volume, and a trend towards a improved New York Heart Association functional class. No significant change in 6-minute walked distance was noted. Sildenafil was well tolerated, although minor expected adverse events were commonly reported. The total dose of sildenafil (mg) was strongly correlated with percent change in nitric oxide metabolite concentration in the plasma (ρ=0.80, P=0.01). There were also significant increases in plasma and erythrocyte arginine concentrations. Our study suggests that sildenafil is safe and may improve pulmonary hemodynamics in patients at risk of pulmonary hypertension; however, it was not demonstrated to improve the distance walked in 6 minutes. Clinical trials are needed to identify the best treatment strategy for pulmonary hypertension in patients with β-thalassemia. (clinicaltrials.gov identifier: NCT00872170).

Topics: Adult; Echocardiography, Doppler; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Pilot Projects; Piperazines; Purines; Risk Factors; Sildenafil Citrate; Sulfones; Thalassemia; Vasodilator Agents

Topics: Adult; Drug Therapy, Combination; Humans; Hypertension, Pulmonary; Male; Pyrimidines; Sildenafil Citrate; Sulfonamides; Thalassemia; Vasodilator Agents