A 58-year-old woman with history of congenital heart defect presented to the pulmonary hypertension (PH) center in World Health Organization functional class III.

A transesophageal echocardiogram demonstrated an ostium secundum atrial septal defect with 14 x 11mm diameter (figure 1 A-B, red arrows, left atrium [LA], right atrium [RA]) and dilated right heart chamber. Right heart catheterization with compartmental oximetry for calculating pulmonary blood flow/systemic blood flow (Qp/Qs) depicted PH with a precapillary phenotype [mean pulmonary artery pressure of 66mmHg, pulmonary vascular resistance of 11.4 WU and pulmonary capillary wedge pressure of 13mmHg] alongside a Qp/Qs of 0.9. Specific PH drugs were started in an upfront combination, including a phosphodiesterase type 5 inhibitor and an endothelin receptor antagonist.

Figure 1

(0.27MB).

Contrast-enhanced chest computed tomography revealed aneurysmal pulmonary arteries partially filled with chronic, laminated, and calcified fibrothrombotic deposits (figure 1 C-E; yellow arrows, right pulmonary artery [RPA], left pulmonary artery [LPA], right upper pulmonary vein [RUPV], left atrial appendage [LAA], aorta [Ao], left ventricle [LV], right ventricle [RV]).

At this stage, differential diagnosis with distinct nosological entities is of upmost importance. The differential diagnosis should include: a) in situ thrombosis due to dilation of pulmonary arteries with stasis, endothelial dysfunction, and a state of hypercoagulability secondary to severe pulmonary arterial hypertension. The etiology would be congenital heart disease: Eisenmenger vs coincidental atrial septal defect (due to its small size); and b) chronic thromboembolic PH with an incidental atrial septal defect.

In this context, a lung perfusion/ventilation scintigraphy was performed revealing multiple ventilation defects with no perfusion mismatch (figure 1F), thereby excluding chronic thromboembolic PH.

This clinical case illustrates in a paradigmatic way the existence of phenocopies regarding distinct pathological conditions. Adequate integration of all clinical elements and demonstration of the absence of ventilation/perfusion mismatch were key elements to correct diagnosis.