Treatment of coronary in-stent restenosis (ISR) by balloon dilatation, brachytherapy, or drug-eluting stents is hampered by a high incidence of recurrent stenosis. Moreover, treating ISR with a drug-eluting stent is a complex procedure that adds another layer of metal to the artery and can create mechanical problems. The SeQuent™ Please drug-eluting balloon may offer a simpler alternative.

The balloon has a unique matrix coating that contains paclitaxel and delivers a dose of drug three times greater than a Taxus stent. The balloon is inflated for about 30 seconds inside the narrowed artery. The paclitaxel, which has a natural attraction to cells, quickly moves from the surface of the balloon into the arterial cells.

Not only does the drug-eluting balloon avoid a second layer of metal inside the artery, there are no polymers that might cause adverse reactions at the target site. Instead, the carrier used to bind paclitaxel to the balloon is iopromide, a commonly used contrast agent.

At ACC.08, investigators presented the results of the Paclitaxel-Eluting PTCA Balloon Catheter in Coronary Artery Disease II-In-Stent Restenosis study or PEPCAD II-ISR. They randomized 131 patients with ISR in a bare-metal stent to treatment with the drug-eluting balloon or the Taxus drug-eluting stent. Five patients were excluded for protocol violations and four patients in the stent group ended up being treated with the drug-eluting balloon.

On an intention-to-treat basis, there was little difference between the two groups. However, an “as-treated” analysis of the 126 patients treated within protocol showed that use of the drug-eluting balloon led to a significant reduction in 6-month late lumen loss (p = 0.03) and in segment binary restenosis (p = 0.007) compared to stent placement. Balloon delivery of the paclitaxel was also associated with a significant reduction in 6 and 12 month major adverse cardiac events (or MACE) compared to a Taxus stent. This difference in MACE was due to a reduction in the need for reintervention.

Importantly, unlike stent placement, combined antiplatelet therapy was continued only for 1 month in the balloon arm, followed by treatment with aspirin alone and there was no evidence of late thrombosis.

Thus, the paclitaxel-eluting balloon catheter is safe and perhaps even more effective than drug-eluting stenting, with the added advantage of only short-term use of antiplatelet therapy. Also, since nothing is left behind in the artery, balloon delivery doesn’t preclude later stent placement or more than one balloon treatment if necessary.

coronary　冠動脈の
in-stent restenosis　ステント内再狭窄
dilatation　拡張
brachytherapy　近接照射療法
drug-eluting stents　薬剤溶出ステント
is hampered by　〜がネックになっている
incidence　発生率
recurrent　再発性の
stenosis　狭窄
procedure　手技
artery　動脈
mechanical problems　機構上の問題
drug-eluting balloon　薬剤溶出バルーン
alternative　代替手段，代わるもの
matrix coating　マトリックス被覆材
paclitaxel　パクリタキセル
delivers　送達する
is inflated　膨らまされる
narrowed artery　狭窄した動脈
attraction　吸着性
Not only does 〜　〜だけではない
polymers　ポリマー
adverse　有害な
carrier　キャリヤー，担体
bind 〜 to …　〜を…に結合させる
iopromide　イオプロミド
contrast agent　造影剤
or　すなわち
bare-metal stent　ベアメタルステント
were excluded　除外された
violations　違反
ended up〜　最終的に〜した
On an intention-to-treat basis　intention-to-treat解析によると
late lumen loss　遠隔期内径損失
in segment　対象病変部内の
binary restenosis　バイナリー再狭窄
placement　留置
（be）associated with　〜に関連した
major adverse cardiac events　主要心イベント
reintervention　再インターベンション
arm　群
followed by 〜　その後〜をした
late thrombosis　遠隔期血栓症
added advantage of　〜というさらなる利点
antiplatelet therapy　抗血小板療法
is left behind　後に残される
preclude　不可能にする，妨げる