Contributed by Thenappan Thenappan, MD
Although a rarer form of pulmonary hypertension, appearing in fewer than 20% of these patients, pulmonary arterial hypertension (PAH) is the most dangerous form of the condition. In PAH, hypertension is isolated to the right side of the heart and the pulmonary vasculature. To confirm a diagnosis of PAH, left heart function must be evaluated in order to rule out other forms of pulmonary hypertension, such as those relating to left heart disease, chronic lung conditions, or thromboembolic disorders. PAH can arise as an idiopathic or heritable condition. It is also associated with other conditions, including connective tissue diseases, such as lupus.1
A 37-year-old patient with confirmed lupus was evaluated at an area hospital for shortness of breath, chest pain, and lower-extremity swelling. She was diagnosed with PAH associated with lupus and given oral sildenafil (20 mg, 3 times a day). After 1 year on this regimen, she developed exercise intolerance and was unable to care for her children. She had a repeat right heart catheterization, and her pulmonary capillary wedge pressure was initially read as 32 mmHg. An echocardiogram suggested abnormal left ventricular function. She was diagnosed with severe left heart failure and referred to University of Minnesota Health Heart Care specialists for evaluation for a heart-lung transplant.
At University of Minnesota Medical Center, physicians performed a comprehensive reevaluation of the patient’s left and right heart function, as part of the center’s standard-of-care procedures. Although M Health Heart Care cardiologists confirmed the diagnosis of severe PAH, tests indicated her pulmonary capillary wedge pressure was 10 mmHg, significantly lower than first reported and within the normal range. Cardiac MRI revealed a slightly reduced cardiac index caused by severe right-heart enlargement, but left heart disease was ruled out. To reduce pressure in the pulmonary arteries, the patient was prescribed an aggressive treatment round of triple combination therapy—intravenous prostacyclin to be increased weekly over 3 months, oral sildenafil, and oral macitentan. After 6 months, her mean pulmonary arterial pressure had dropped from 53 mmHg to 27 mmHg. (A pressure of 25 mmHg is considered normal.) Her right atrial pressure had dropped from 26 mmHg to 4 mmHg, which is within the normal range. Her exercise tolerance had improved, and she was able to resume caring for her children.
Intravenous line infections prompted a switch from intravenous prostacyclin to oral selexipag, a new prostacyclin receptor agonist. The new regimen has proven effective. More than 2 years later, she remains active with stable heart function on a simple treatment regimen of 3 daily oral medications.
In patients with severe PAH, measurements of capillary wedge pressure to rule out left heart failure must be performed with special skill in order to avoid false high readings. Incorrect measurements can result from “partial wedging,” or trapping of the Swan-Ganz catheter in thickened pulmonary arteries. As a result of comprehensive reevaluation by skilled specialists, this patient was spared a heart-lung transplant.
New drug therapies and surgical interventions are extending the life expectancy of patients with pulmonary hypertension, a condition that, while rare, complicates the course of many diseases.Continue reading