3枝病変に対しCABGは依然としてPCIよりも望ましい

CREDO-Kyoto：3枝病変患者において重篤な有害事象はCABGよりもPCIの方が多い
CREDO-Kyoto: PCI associated with more serious adverse events than CABG in patients with triple vessel disease
2011年European Society of Cardiology学会で発表されたCREDO-Kyoto PCI/CABGレジストリコホート2の結果から、3枝病変を有する患者において経皮的冠動脈形成術（PCI）は冠動脈バイパス術（CABG）よりも重篤な有害事象発現率が有意に高いことが示された。今回の解析に使用されたスタディ対象は、3枝病変を有する患者2,981人（PCI1,825人、CABG1,156人）であった。スタディ一次エンドポイントは総死亡、心筋梗塞（MI）、および脳卒中の合計であった。3年間のこれらの一次エンドポイント到達率およびMI発現率はCABGと比較しPCIにおいて高かった（補正後のハザード比（HR）それぞれ1.47[95%CI 1.13-1.92, P=0.004]；HR 2.39 [95% CI 1.31-4.36, P=0.004]）。しかし、総死亡率はPCI後の方が有意に高かった（HR 1.62 [95% CI 1.16-2.27, P=0.005]）にも関わらず、心臓死リスクに関しては有意差はなかった。SYNTAXスコアの低い（<23）または中等度（23-32）の患者における一次エンドポイント発現率はPCIとCABGとで同等であったが、SYNTAXスコアが高い（≥33）患者においてはCABGよりもPCI後に明らかに高かった（それぞれ15.8%と12.5% .P=0.25、18.8%と16.7% ,P=0.24、27.0%と16.4% ,P=0.004）。
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Results from CREDO-Kyoto PCI/CABG Registry Cohort-2 presented at the 2011 ESC Congress show that percutaneous coronary intervention (PCI) was associated with significantly higher risk for serious adverse events in patients with triple vessel disease than coronary artery bypass grafting (CABG).

These registry findings, derived from the largest ever study population of triple vessel disease patients with SYNTAX score assessment, are consistent with those found in the SYNTAX randomized trial. However, said Dr. Shiomi, while the observations were striking in patients with triple vessel disease, the selection of revascularization strategies in patients with less complex coronary anatomy "deserves further consideration".

As background to the report, he explained that PCI has been widely performed in patients with severe coronary disease (such as left main or triple vessel coronary artery disease) following the introduction of drug-eluting stents. However, long-term clinical outcomes of PCI relative to CABG in such patients have not yet been adequately evaluated. Although three-year results from the SYNTAX trial suggested that an excess risk of PCI relative to CABG for death, myocardial infarction or stroke was significant in the triple vessel disease subset, there were limitations in the apparent lack of statistical power to evaluate this composite endpoint.

The CREDO-Kyoto (Coronary REvascularization Demonstrating Outcome Study in Kyoto) PCI/CABG registry cohort-2 is a physician-initiated non-company sponsored 26-center registry enrolling consecutive patients having a first coronary revascularization between January 2005 and December 2007. The study population for the current analysis consisted of 2981 patients with triple vessel disease (PCI 1825 patients, and CABG 1156 patients). To ensure comparability between the PCI and CABG groups (in an observational study), anatomic complexities of coronary artery disease were assessed by using the SYNTAX score.

The primary endpoint of the study was a composite of all-cause death, myocardial infarction (MI) and stroke. PCI as compared with CABG was associated with a higher 3-year risk for this primary endpoint (adjusted hazard ratio (HR) 1.47 [95% CI 1.13-1.92, P=0.004]) and for MI (HR 2.39 [95% CI 1.31-4.36, P=0.004]). However, the risk for cardiac death was not significantly different (HR 1.30 [95% CI 0.81-2.07, P=0.28]), although the risk for all-cause death was significantly higher after PCI (HR 1.62 [95% CI 1.16-2.27, P=0.005]).

Results also showed that the cumulative incidence of the primary endpoint was comparable between the PCI and CABG groups in patients with low (<23) and intermediate (23-32) SYNTAX scores, but in patients with high SYNTAX scores (?33) was markedly higher after PCI than after CABG (15.8% and 12.5%, P=0.25, 18.8% and 16.7%, P=0.24, and 27.0% and 16.4%, P=0.004, respectively).

However, the adjusted risk of PCI relative to CABG for the primary endpoint was HR 1.66 (95% CI 1.04-2.65, P=0.03) in the low-score category, HR 1.24 (95% CI 0.83-1.85, P=0.29) in the intermediate-score category, and HR 1.59 (95% CI 0.998-2.54, P=0.051) in the high-score category. "Further studies are therefore warranted to investigate whether PCI is a viable option in patients with less complex coronary anatomy," said Dr. Shiomi.