This woman's uncorrected atrial septal defect has led to pulmonary arterial hypertension (PAH) a condition in which pulmonary vessels undergo irreversible vasoconstriction and remodeling
Although some cases of PAH (defined as pulmonary arterial pressures > 25 mmHg at rest) are idiopathic, a variety of underlying etiologies can be seen as well, including: genetics, drugs, connective tissue disease, HIV, congenital heart defects, schistosomiasis, chronic hemolytic anemia and portal hypertension. Women aged 30-50 are most commonly affected. In those with congenital heart disease, chronic left to right intracardiac shunting leads to volume overload in the lungs. In response, smooth and endothelial muscles cells over-proliferate and vasoconstriction occurs.
Stringham and Shah summarize the latest information in respect to diagnosis and treatment of PAH. They emphasize that work-up for the condition should include echocardiography and right heart catheterization. Treatments include diuretics, oxygen, anticoagulation, prostacyclin analogues, endothelin receptor antagonists, and phosphodiesterase type 5 inhibitors.
Farber and Loscalzo, in a review of PAH, emphasize that the pathophysiology can be summarized as an imbalance in vascular effectors. Normally, a balance exists between vasodilators and vasoconstrictors, between pro- and anti-thrombotic factors, and between smooth-muscle cell and endothelial cell proliferation. In PAH, this balance is disrupted. Specific factors affected include nitric oxide, endothelin-1, and prostacyclin, among others.
Illustration A depicts the macroscopic changes that occur in the heart and lungs with PAH.
Illustration B is a diagram that explains the pathophysiology of PAH.
Answers 2 & 3: PAH does lead to right heart strain, but with treatment, this dysfunction can improve.
Answers 4 & 5: PAH does not directly damage the aorta, IVC, or SVC.
Stringham R, Shah NR. Pulmonary arterial hypertension: an update on diagnosis and treatment. Am Fam Physician. 2010 Aug 15;82(4):370-7.
PMID:20704168 (Link to Abstract)
Farber HW, Loscalzo J. Pulmonary arterial hypertension. N Engl J Med. 2004 Oct 14;351(16):1655-65.
PMID:15483284 (Link to Abstract)
USMLE World Step 1 QBank Question #201. Copyright © USMLEWorld, LLC 2012