When do you consider the use of PH specific therapies in patients with pre-capillary pulmonary hypertension associated with sickle cell disease?

Sickle cell-associated PH would be considered Group V PH. Evidence for treating sickle-associated pre-capillary PH with Pulmonary vasodilator therapies is poor. So, in a garden variety of sickle cell anemia associated with PH, I tend not to treat it with PV meds. If the PVR increases, I may sometimes consider an endothelin receptor antagonist or prostacyclin analog. Avoid PDE5 inhibitors for sicklers. Some sicklers may have PE evidence and must be screened for CTEPH.

I agree with Dr. @Dr. First Last's comments above. This is a complex topic and patients with these problems should be evaluated at a center with expertise in sickle cell disease and PAH treatments. I would add two points:

First, screening for PH in patients with sickle cell disease should be with an echocardiogram however screening test characteristics in SSD are sub-optimal (i.e. specificity for PAH is poor) and confirmation by RHC is imperative. A true pulmonary vasculopathy with precapillary hemodynamics (PAH) is less common than other PH pathophysiology in SSD. After a screening echo, it's more common to find other things: no PH, high cardiac output state, left heart remodeling possibly from iron overload states causing pulmonary venous...