INTRODUCTION: Over 1/3 of patients with cystic fibrosis (CF) develop pulmonary hypertension (PH). Targeted therapy (TT) has shown benefit in PH. However, the effect of TT in PH secondary to lung diseases (PHSLD) is uncertain as it may worsen hypoxemia. In our case enhanced oxygenation combined with TT proved beneficial.
CASE PRESENTATION: A 35 yo female with severe CF was evaluated for lung transplantation. Baseline PaO2 on 2 L/m O2 via nasal canula was 67 mmHg. Echocardiogram showed PH and patent foramen ovale (PFO). Cardiac catheterization documented pulmonary artery pressure (PAP) of 54/29 mmHg. The patient was started on Sildenafil but within 2 days her dyspnea worsened and PaO2 dropped to 42 mmHg on 60% O2. Chest radiograph showed bronchiectasis without new changes. She was started on BiPAP and her PaO2 returned to baseline 2 days after discontinuation of Sildenafil. The patient remained severely dyspneic from worsening PH and therefore a strategy of guaranteed oxygenation plus TT was attempted. She was placed on continuous BiPAP with enhanced O2 supplementation adjusted to keep SaO2 100% before re-initiation of TT. Since the patient refused to restart Sildenafil, Bosentan was started and increased to maximal doses in 2 days. She tolerated pulmonary vasodilation well. 2 weeks later, repeat echocardiogram estimated systolic PAP <40mmHg and PFO was no longer seen. One month later, exercise tolerance had improved significantly and O2 requirement was lower than at baseline.
DISCUSSION: When TT was tested for PHSLD, PAP improved but was accompanied by worsening hypoxemia with increased V/Q mismatch likely from inhibition of hypoxic vasoconstriction (1). For this reason, current recommendations are against use of TT in PHSLD (2). However, when the data are examined in further detail, in the same group of patients tested, oxygen delivery remains unchanged despite worse hypoxemia as cardiac output has improved. Thus, if oxygenation is guaranteed through enhanced supplementation, TT may result in a net improvement in both pulmonary hemodynamics and oxygenation. Our case proves the feasibility of such a strategy.
CONCLUSIONS: Our case demonstrates that TT holds promising potential in PHSLD if oxygenation can be guaranteed.
Reference #1 Isabel Blanco, Elena Gimeno, Phillip A. Munoz, Sandra Pizarro, Concepcio Gistau, Robert Rodriguez-Roisin,Josep Roca, and Joan Albert Barbera Hemodynamic and Gas Exchange Effects of Sildenafil in Patients with Chronic Obstructive Pulmonary Disease and Pulmonary Hypertension, Am J Respir Crit Care Med 2010: 181, 270-278
Reference #2 A. Chaouat, R. Naeije and E. Weitzenblum, Pulmonary hypertension in COPD Eur Respir J 2008; 32: 1371-1385
DISCLOSURE: The following authors have nothing to disclose: Vipul Patel, Renli Qiao
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