Portal de Periódicos da CAPES

Effect of Aerosol Heparin on the Development of Hypoxic Pulmonary Hypertension in the Guinea Pig

1993; American Thoracic Society; Volume: 148; Issue: 1 Linguagem: Inglês

10.1164/ajrccm/148.1.241

2376-3752

C. R. Spence, Bruce Thompson, Stefan Janssens, Daniel M Steigman, Charles A. Hales,

Cardiovascular Effects of Exercise

Chronic hypoxia produces pulmonary artery hypertension through vasoconstriction and structural remodeling of the pulmonary vascular bed. The present study was designed to test the effect of heparin administered via aerosol on the development of hypoxic pulmonary hypertension. Anesthetized, intubated, and mechanically ventilated guinea pigs received an aerosol of either 2 ml normal saline (hypoxic control, HC) or 4,500 units of heparin diluted in 2 ml normal saline via an ultrasonic nebulizer (hypoxic heparin, HH). After 24 h of recovery, the animals were placed in a hypoxic chamber (10% O2) for 10 days. Animals kept in room air served as normoxic controls (NC). Hypoxia increased mean pulmonary artery pressure from 11 ± 1 (SEM) mm Hg in NC to 24 ± 1 mm Hg in HC (p < 0.05). Pulmonary artery pressure was significantly lower in HH-treated animals (20 ± 1 mm Hg, p < 0.05 versus HC) as was the total pulmonary vascular resistance (0.15 ± 0.01 in HH versus 0.20 ± 0.01 mm Hg/ml/min in HC, p < 0.05). There was no difference in cardiac output (146 ± 12 in HH versus 126 ± 7 ml/min in HC), hematocrit (57 ± 2 in HH versus 56 ± 2% in HC), partial thromboplastin time (30 ± 2 in HH versus 32 ± 3 s in HC), prothrombin time (46 ± 1 in HH versus 48 ± 4 s in HC) or room air arterial blood gas values after 10 days of hypoxia. The proportion of thick-walled peripheral vessels (30 ± 2 in HH and 35 ± 1 in HC versus 14 ± 2% in NC, p < 0.05) and the percent medial thickness of pulmonary arteries adjacent to alveolar ducts (7.2 ± 0.2 in HH and 7.1 ± 0.5 in HC versus 4.9 ± 0.4% in NC, p < 0.05) and to terminal bronchioles (27.0 ± 2.1 in HH and 26.6 ± 1.5 in HC versus 16.4 ± 1.9% in NC, p < 0.05) increased to a similar degree in both hypoxic groups. We conclude that a single dose of heparin when administered by aerosol prior to 10 days of hypoxia reduces the development of pulmonary hypertension.