Thallium 201心筋シンチグラムによる原発性肺高血圧症の評価

Thallium-201 myocardial scintigram in primary pulmonary hypertension

　原発性肺高血圧症は原因不明の肺高血圧をきたす予後不良の疾患である^1）。その診断には右心カテーテル検査が必要であるが，そのリスクは他の心肺疾患に比べ，著しく高いことが報告されている^2）。しかし，予後の判定および治療上，循環動態の把握は不可欠である。

　そこで最近，虚血性心疾患の診断に広く用いられている新しい非侵襲検査，タリウム201心筋シンチグラムを応用し，原発性肺高血圧症における右室負荷の評価を試みた。

Right heart catheterization is needed for the diagnosis of pulmonary hypertension in patients with primary pulmonary hypertension (PPH), though the procedure was reported to have an un-usually high risk. We examined the usefulness of thallium-201 myocardial scintigraphy for the evalu-ation of right ventricular overloading in patients with PPH. This study includes 5 patients with PPH, diagnosed by the clinical criteria of research commit-tee of PPH in the Ministry of Health and Welfare in Japan (1976). Autopsy was done and diagnosis was confirmed in 4 cases.

The right ventricular (RV) free wall was visualiz-ed in all cases. They were divided into 2 groups by the degree of visualization. The cases with heavier visualization had a higher pulmonary arterial resis-tence. The shape of the interventricular septum was deformed in all cases. It was straight in 3 cases and convex to the left ventricle (LV) in 3. In the later group, a systolic LV-RV pressure difference was less than 25 mmHg. One of these 3 cases showed reversed pressure difference.

We concluded that thallium-201 myocardial scintigraphy could non-invasively assess the degree of RV overloading in PPH.