経管式冠動脈形成術（TCA）前後の左室機能

Left ventricular function prior to and after transluminal coronary angioplasty (TCA)

　経管式冠動脈形式術（transluminal coronary angio—plasty＝TCA）とは，非手術的にバルーンで冠動脈の粥状硬化性狭窄を物理的に圧排してしまうという狭心症の根本的な治療法である^1〜4）。本法は臨床の現場に導入されてからまだ日が浅く，多数例について左室機能を検討した論文は殆んどみあたらない^5,6）。

　この論文の目的は，TCA前後に行った運動負荷心電図法と心電図同期式放射性心室造影法（RNVG）によって左室機能を評価検討し，その効果を明らかにすることにある。

The effect of TCA upon left ventricular func-tion and exercise capacity was studied non-inva-sively using exercise electrocardiography (ExECG) and radionuclide ventriculography (RNVG) in 48 patients with coronary artery disease. These patients were divided into three groups. Group 1, 28 patients (mean age 49) with successful TCA : group 2,6 patients (mean age 48) who underwent aorto-coronary bypass surgery (AC-BS) because of unsuccessful TCA : group 3, total of 15 patients including 5 patients with unsuccessful TCA for the control study. Twelve patients with successful TCA reevaluated after 3 months.

ExECG and Tl-201 myocardial scintigraphy (TMS) using arm-assisted step test were done 3-5 days prior to and after scheduled TCA: as to the group 2 patients within 5 months after AC-BS. Parameters obtained were duration of exercise, left ventricular ejection fraction (EF), mean systolic ejection rate (MSER), max dC/dt/ED and max dC/dt/ES.

In group 1, luminal diameter of coronary artery stenosis before TCA 83.6±7.5% was dilated to 43±14.5% (p<0.001). EF both at rest and during exercise increased significantly from 46.8± 9.5% and 39.6±10.7% to 51.9±9.4% and 49.4±10.9%, respectively (each p<0.001) following TCA. Other parameters showing left ventricular myocar-dial function increased significantly after the procedure. However, no changes were noted in these parameters in group 3.

These short time results suggest TCA improves coronary perfusion to ischemic areas supplied by critical coronary artery stenosis and hence increases left ventricular function especially during exercise.