Letter by Alfonso et al Regarding Article, “Paclitaxel-Coated Balloon Catheter Versus Paclitaxel-Coated Stent for the Treatment of Coronary In-Stent Restenosis”
To the Editor:
We read with great interest the elegant randomized study by Unverdorben et al1 comparing paclitaxel-eluting balloons (PB) (66 patients) with paclitaxel-eluting stents (65 patients) in patients with bare-metal in-stent restenosis. The authors should be commended for their important article confirming the unique efficacy of PB in this challenging anatomic scenario. Some issues, however, deserve consideration.
First, the primary end point of the study was the angiographic late loss at 6 months. Patients allocated to the PB group had a significantly lower late loss than those in the paclitaxel-eluting stent group (0.17±0.42 mm [median 0.09] versus 0.38±0.61 mm [median 0.24], P=0.03). However, although angiographic late loss is frequently used as a surrogate end point to assess stent results, its value for comparing different interventional strategies (namely, balloon angioplasty versus stenting) is severely limited. Indeed, late loss is closely linked to acute gain (the more you gain, the more you lose law), which, systematically, is larger after stent implantation. Accordingly, a reduced late loss should be expected after any type of balloon angioplasty. In a previous randomized study comparing balloon angioplasty with bare-metal stents in patients with in-stent restenosis, we found that both strategies yielded similar long-term clinical and angiographic results, yet angiographic late lumen loss was significantly reduced after balloon angioplasty.2 Of interest, in the study of Unverdorben et al,1 the minimal lumen diameter at follow-up was virtually identical in both arms (in-stent [2.08±0.56 versus 2.11±0.78 mm], in-segment [2.03±0.56 versus 1.96±0.82 mm]).
Second, the angiographic late loss found in the current study was 6 times larger than that initially reported in the pivotal randomized study demonstrating the efficacy of PB in this setting (0.03±0.48 mm).3 However, patterns of restenosis and lesion lengths (major determinants of outcome) were more favorable in the current article. Therefore, additional insights on this important issue would be highly appreciated.
Finally, the strong trend suggesting clinical benefit at 1 year in the PB group is difficult to interpret. The lower need for target vessel revascularization, in light of similar angiographic findings at follow up, should be further explained. We believe that the low number of patients included in the study precludes any further analysis in this regard, especially considering that demonstration of ischemia was not required before repeated interventions and also that the investigators were not blinded to treatment allocation. Furthermore, late stent thrombosis (another potential concern after paclitaxel-eluting stents) was not detected in any patient.
We fully agree4 with the suggestion that, whenever possible, unrestricted repeated stent implantation (onion skin strategy) should be avoided in patients with recurrent in-stent restenosis. In this regard, and especially considering the disappearance of coronary brachytherapy from our armamentarium,5 the excellent results obtained with PB in the current article are highly reassuring.
Unverdorben M, Vallbracht C, Cremers B, Heuer H, Hengstenberg C, Maikowski C, Werner GS, Antoni D, Kleber FX, Bocksch W, Leschke M, Ackermann H, Boxberger M, Speck U, Degenhardt R, Sheller B. Paclitaxel-coated balloon catheter versus paclitaxel-coated stent for the treatment of coronary in-stent restenosis. Circulation. 2009; 119: 2986–2994.
Alfonso F, Zueco J, Cequier A, Mantilla R, Bethencourt A, López-Minguez JR, Angel J, Augé JM, Gómez-Recio M, Morís C, Seabra-Gomes R, Pérez-Vizcayno MJ, Macaya C. A randomized comparison of repeat stenting with balloon angioplasty in patients with in-stent restenosis: restenosis intra-stent: balloon angioplasty versus elective stenting (RIBS) investigators. J Am Coll Cardiol. 2003; 42: 796–805.
Alfonso F, García J, Pérez-Vizcayno MJ, Lorenzo L, Hernández R, Escaned J, Jiménez-Quevedo P, Bañuelos C, Macaya C. New stent implantation for recurrences after stenting for in-stent restenosis: implications of a third metal layer in human coronary arteries. J Am Coll Cardiol. 2009; 54: 1036–1040.