完全冠血行再建という視点よりみた冠動脈狭窄病変の病型分類

Angiographical classification of coronary artery disease from the viewpoint of complete revascularization

　ACバイパス術に際して，有意な狭窄病変を有する冠動脈の全てにバイパス・グラフトが移植された場合に，完全冠血行再建（complete revascularization）という用語が用いられる^1,2）。

　ACバイパス術後の狭心痛の消失あるいは改善は，完全冠血行再建の有無と関係があり^1），初回のACバイパス術で有意な狭窄病変を有する冠動脈にグラフトが植えられず病変が残存した場合，狭心痛が再発し再手術の原因となる^3,4）。また，左室瘤切除術において，ACバイパス術を同時に行った方が左室瘤切除のみを行った場合に比べて，術後遠隔期には有意に無症状の患者が多い^5）。これらの点より，完全冠血行再建の重要性が強調されている。

Coronary arteriography using cranial and caudal angulation was undertaken in 73 patients (MI 31, angina pectoris 42) with more than 75% luminalnarrowing of AFIA coronary angiographic classifica-tion.

Lesions of coronary arteriosclerosis were classified into 3 types due to the location of stenosis : type 1 is the lesions located in the main coronary arteries such as LAD, LCX and RCA, type 2 is the stenoses at the branching portion of the main coronary arteries and the origin of the branches such as diagonal, obtuse marginal, posterior descending and posterior left ventricular branches, type 3 is the narrowings localized in the branches. The branches with small caliber less than 1.0 mm were excluded in this classification.

From the viewpoint of complete revasculariza-tion, the lesions of type 2 require two grafts, one to the main coronary artery and the other to the branch. Mixed types, which variably combine type 1, type 2 and type 3, also necessitate two grafts or more, although single graft is enough for type 1 or type 3.

Of 64 patients with the stenoses in LAD region, 23 patients (36%) had the lesions of type 1, 10 (16%) type 2,4 (6%) type 3 and 27 (42%) mixed types. Two or more grafts were subsequently indicated in the region of LAD in 37 patients (58%).

Thirty-four patients revealed the narrowings in LCX region. Type 1 was found in 9 patients (26%), type 2 in 4 (12%), type 3 in 8 (24%) and mixed types in 13 (38%). Seventeen patients (50%) with type 2 or mixed types were judged to need two or more grafts in LCX region.

There were 42 patients with the stenotic lesions in RCA, of which 26 (62%) showed type 1 stenosis, one type 2,4 (10%) type 3 and 11 (26%) mixed types. Single graft was enough in 72% of patients with RCA lesions.

In order to evaluate exactly the location of stenotic lesions, which may or may not include the origin of branches, hemiaxial angulation is frequently diagnostic. Cranial angulation in LAO is valuable for proximal LAD lesions and distal RCA lesions. Caudal angulation is useful for the detection of stenosis in ramus medialis.