At least 15-20% of patients previously thought to have IPAH actually have a familial form of PAH involving at least one genetic defect.
The most common genetic defect in these cases involves the BMPR-II gene.
Definition Characteristics Clinical group(s)b Pulmonary hypertension Mean PAP 25 mmHg All Pre-capillary PH Mean PAP 25 mmHg PWP 15 mmHg CO normal or reduced 1. Pulmonary arterial Hypertension 3. PH due to lung diseases 4. Chronic Thromboembolic PH 5. PH with unclear and/or Multifactorial mechanisms Post-capillary PH Passive TPG 12 mmHg Reactive (out of proportion) TPG .12 mmHg Mean PAP 25 mmHg PWP .15 mmHg CO normal or reducedc 2. PH due to left heart disease
Excluding autoimmune disorders is an important part of the workup in a patient with suspected pulmonary hypertension. Reportedly, up to 40% of patients with IPAH have a positive finding on an antinuclear antibody (ANA) assay but no other clinical manifestations of autoimmune disease.
Screen for thyroid abnormalities during the initial workup for IPAH because these abnormalities are common in patients with IPAH. Thyroid abnormalities may be the cause of or contribute to symptoms similar to IPAH. In addition, hyperthyroidism itself may lead to an elevation in pulmonary artery pressure.
Assessment of aerobic capacity and ventilatory efficiency can help identify a pulmonary vascular limit to exercise and can be used to differentiate intrinsic pulmonary vascular disease from cardiac deconditioning and restrictive or obstructive lung disease or left-sided cardiac dysfunction.
-TYPE NATRIURETIC PEPTIDE Levels of B-type natriuretic peptide (BNP) and N-terminal BNP have been shown to be elevated in patients with IPAH, and levels appear to be prognostic.
Parenteral vasodilators are used for patients whose IPAH fails to respond to calcium channel blockers or who cannot tolerate these agents and who have New York Heart Association (NYHA) type III or IV right-sided heart failure. PGI2 ANALOGUES
Epoprostenol In addition ,this agent also contributes to inhibition of platelet aggregation n inhibition of smooth muscle proliferation.
Endothelin receptor antagonists (ERAs) are therapeutic alternatives to parenteral prostacyclin agents. Given orally, they competitively bind to endothelin 1 (ET-1) receptors endothelin-A and endothelin-B,
causing a reduction in pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR), and mean right atrial pressure (RAP).
This agent is indicated for treatment of PAH in patients with WHO class III or IV symptoms to improve exercise ability and decrease the rate of clinical deterioration.
A single- or double-lung transplant is indicated for patients who do not respond to medical therapy.
Atrial septostomy is a palliative procedure allowing interatrial right-to-left shunting to occur, thus delivering more overall oxygen content to the respiring tissues, albeit with a lower overall saturation.