合成エストロゲン製剤の使用に伴い，血栓が原因と考えられる人工弁機能不全を生じた１例

Bioprosthetic Valve Thrombotic Dysfunction after Estrogen Therapy for Prostatic Cancer

要旨

　患者は88歳時に老人性大動脈弁狭窄症に対し生体弁による大動脈弁置換術を施行した90歳，男性．術後15カ月時に前立腺癌に対し合成エストロゲン製剤(ES)の内服を開始した．内服開始8日前の弁機能は心エコー図で弁口面積(AVA)1.1cm²，最大圧較差(PG)42.3mmHgであった．内服開始10日後に労作時息切れが出現し，胸部X線写真で心拡大，肺うっ血，右胸水貯留を認め入院となった．弁機能はAVA0.7cm²，PG77.4mmHgと悪化し，経食道心エコー図では大動脈弁左室側に血栓様の異常構造を認めた．ESの内服により血栓による弁機能不全を生じたと考えESを中止し，内服していたアスピリンにワルファリンを追加したところ，7週後の弁機能はAVA1.3cm²，PG30.9mmHgと正常化した．血尿のため13週後までにアスピリン，ワルファリンも中止したが，ES中止49週後の弁機能に悪化は認められない．

Summary

　A 90-year-old male underwent aortic valve replacement with bioprosthetic valve when he was 88 years old. He began to receive estrogen(fosfestrol) and aspirin for prostatic cancer 15 months after the aortic valve replacement.Echocardiographicaorticvalvearea(AVA) and peak pressure gradient(PG) were 1.1cm² and 42.3mmHg before estrogen therapy. Ten days after starting estrogen therapy, he visited our hospital due to dyspnea on effort. The chest X-ray showed pulmonary congestion and right pleural effusion. AVA and PG were 0.7cm² and 77.4mmHg. A low echogenic mass was observed in the left ventricular outflow tract by transesophageal echocardiography. As thrombotic dysfunction of the bioprosthetic valve was suspected, estrogen was stopped and warfarin potassium was added. Fifty days after estrogen was stopped, AVA and PG were 1.3cm² and 30.9mmHg. The prosthetic valve function was not worsened 4 month after the cessation of aspirin and warfarin because of hematuria. When estrogen is administered to patient with cardiac disease, the possibility of thrombotic complication must be considered.