text: Pulmonary<unk>  may be caused by either left heart failure (the most common cause) or other somewhat common causes such as HIV, systemic sclerosis, portal<unk> , congenital heart disease, and sickle cell disease.
  The World Health Organization (WHO) has classified PH based on etiology into five distinct groups: Group 1 (pulmonary arterial<unk> , Group 2 (PH due to left heart failure), Group 3 (PH due to chronic lung disease and/or hypoxemia), Group 4 (PH due to chronic thromboembolic disease), and Group 5 (PH due to multifactorial mechanisms).
option_0: Pulmonary hypertension causes
option_1: Pulmonary edema causes
option_2: Air embolism causes
option_3: Pulmonary valve stenosis causes
option_4: Ventricular septal defect causes
option_5: Aortic stenosis causes
option_6: Patent ductus arteriosus causes
option_7: Tracheitis causes