I do not if this this has ever been studied. Because many older thal minors show symptoms of mild pulmonary hypertension, and the same factors that cause PHT in thals intermedia and major, are also present to a lesser extent, I tend to recommend that older thal minors take L-carntine, L-arginine or L-citrulline, along with natural vitamin E complex and magnesium, all to help counter the long term effects of thal minor on the heart and pulmonary artery.