TAT and pulmonary arterial hypertension: Though the exact etiology by which HIV causes PAH is unknown, 3 distinct proteins: Nef, Tat, and gp120, have been associated with vascular changes in PAH [1, 5] Pulmonary hypertension (PH) related to diastolic dysfunction can be secondary to alterations of left ventricular (LV) function that may be related to myocardial damage induced by the virus [6].