Patient case: An 18-year-old male patient with homozygous hemoglobin SS disease was evaluated for progressive dyspnea and elevated tricuspid regurgitant jet velocity (TRV) on echocardiography. The patient's case is described in detail in Lancet1 He had been treated with regular transfusions since childhood for stroke, had rare episodes of vaso-occlusive pain episodes, and did not take narcotic pain medications. He presented with progressive severe dyspnea on exertion and lower extremity edema. His laboratory tests were notable for a total hemoglobin level of 11.8 g/dL and hemoglobin S levels <30% but with 18% reticulocytes and elevated markers of hemolysis, such as high plasma levels of lactate dehydrogenase, aspartate amino transferase, and indirect bilirubin. The computed tomography scan of his chest in Figure 1A-B shows a large pulmonary artery, which has a greater diameter than his aorta, and a mosaic perfusion pattern, typical for severe pulmonary arterial hypertension. His Doppler echocardiographic study (Figure 1C) showed an unusually high TRV of 5.93 m/s, consistent with a calculated pulmonary artery systolic pressure of >140 mm Hg (4 times the TRV squared = 4V2). Additional images in Figure 1D show a dilated right ventricle and right atrium with a compressed left ventricle. The patient's right heart catheterization revealed a pulmonary artery systolic pressure of 147 mm Hg and diastolic pressure of 49 mm Hg; note that the normal values are ∼25/10 mm Hg.
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