The pathophysiology is due to diastolic pressure variations between the pulmonary artery and right ventricle, differences are often very small, but increase regurgitation. An elevation in<unk>  due to elevated intrathoracic pressure is relevant in ventilated patients (having acute restrictive right ventricular physiology). The reasons for changes in stiffness of the right ventricle's walls are not well understood, but such stiffness is thought to increase with hypertrophy of the ventricle.
Pulmonary insufficiency
Obstructive lung disease
Chronic cough
Cardiomegaly
Pulmonary toxicity
Tracheobronchomegaly
Airway obstruction
Exercise intolerance