Progression usually occurs in 2 phases hase a pulmonary artery vasospasm with pulmonary hypertension and elevated right ventricular pressure cause hypoxia Hypoxia causes myocardial capillary damage and pulmonary capillary damage, eft heart failure, and acute respiratory distress syndrome.◼ . Progression usually occurs in 2 phases. ◼ phase I: ◼ pulmonary artery vasospasm with pulmonary hypertension and elevated right ventricular pressure cause hypoxia. ◼ Hypoxia causes myocardial capillary damage and pulmonary capillary damage, left heart failure, and acute respiratory distress syndrome. ◼