短期間に左房内血栓の出現，退縮をみた僧帽弁狭窄症の1例

A case of mitral stenosis with left atrial thrombus arose and reduced in a short term

　左房内血栓は，僧帽弁狭窄症の10〜30％に合併し^1,2），また左房内血栓の存在する例では塞栓症の発生頻度が33〜67％と高い^2〜4）とされている。最近では，超音波断層法の発達により，多くの例で心内血栓の診断，経過観察が可能となっており，血栓に対する溶解療法や抗凝固療法の有用性について，いくつか報告があるが^4〜6），一方では自然経過での血栓の増大，退縮が知られており^6,7），治療の面でも多くの問題が残されている。

　今回，我々は，軽症の僧帽弁狭窄症で加療中に左房内血栓の出現を認め，血栓の進展を予防する目的でワーファリン2mg／日，アスピリン81 mg／日を投与し，塞栓症の合併なく，約1ヵ月の経過で血栓の退縮を観察し得た症例を経験したので，ここに報告する。

A case of mitral stenosis with left atrial thrombus which rapidly arose and reduced within a month was reported. A 61-year-old female was admitted to our hospital on November 14, 1986 because of a syn-copal attack due to ventricular tachycardia. On ad-mission she had typical auscultatory signs of mitral stenosis, mild hepatomegaly and no neurological ab-normality. Laboratory findings included coagulation studies were normal, and atrial fibrillation was noted on ECG. Heart catheterization revealed low cardiac output, the mitral orifice area to be 2. 4 cm² and left ventriculography showed mild mitral regurgitation. Ventricular tachycardia was controlled following im-provement of heart failure. On two-dimensional echocardiography performed on December 24, left atrial thrombus was revealed which was not detected on December 3. Through the continuous administra-tion of warfarin and aspirin to prevent the thrombus' growth, it markedly reduced in size, from 3 x 2 x 4. 5 cm on December 24, 1986 to 1.5 x 1 , 2.5 cm on January 30, 1987 without systemic embolism. Then a mitral valve replacement and a left atrial thrombectomy were performed on February 3, with the removal of a red thrombus, partially organized, measuring 1×0.7×2.5 cm.

This case is unique in its clinical outcome and further investigation is necessary for the manage-ment of patients as our case.