Benefits of Cutting Balloon Before Stenting “Cut and Stent”

Neointimal hyperplasic response following angioplasty (PTCA), and especially stent implantation, is linked to overstretch injury, causing modulation of the vascular cytoskeleton and subsequent production of mediators.1 These result in smooth muscle cell migration and replication, and production of extra cellular matrix.2–7 These processes associated with vascular remodeling or lack of adequate vascular compliance result in restenosis. Stents have been demonstrated to affect a larger post-angioplasty lumen.8,9 This results in reduced restenosis, in spite of an increased neointimal response when compared with balloon alone.10 New stent designs have emerged in an attempt to improve on the deficiencies of the first-generation stents such as excessive rigidity, articulation gaps and non-uniform expansion.11 The ability to adequately deploy a stent with fewer traumas to the vessel wall due to improved radial compliance may therefore result in reduced neointimal formation. Stents have been shown to reduce the incidence of restenosis.8,9 They prevent arterial recoil and negative or deleterious remodeling by offering a scaffolding (geometrical support) to keep the vessel open.10,12 However, they do cause some focal necrosis at the site of indentation into the media. Histological and IVUS studies suggest that stents induce a greater intimal proliferative response than PTCA alone.13 Thus, it was conjectured that cutting balloon (CB) induced controlled dissection prior to stent deployment would result in increased vascular radial compliance. This, in turn, could result in a decrease of strut-induced medial necrosis and the potential reduction of the stimulus for neointimal proliferation. This would also be coupled with the scaffolding benefits of the implanted stent. All stent designs have been shown to induce similar changes. However, recently stent versus stent trials have demonstrated that the newer generation stents tend to have less restenosis than the originally clinically approved stents.14 This may be design related, with the absence of a central articulation and greater compliance during balloon inflation deployment, resulting in better apposition with lower pressure inflations.11,15 CB can achieve scoring and full inflation at a pressure as low as 4 atmospheres, which can be effective for a non-compliant balloon, and we certainly miss the IVUS analysis right after this inflation to understand if the lesion was adequately prepare for stenting. No information about the stents used was given in the study; will different stents behave the same fashion after cutting balloon? The modification of the compliance engendered by the CB may transform the behavior delivery of the stents, which surely “were not created equal”. All “atherectomy devices” will generate some embolization —are we missing information about the timing of such embolization to point out the responsible: CB or stent — or lesion? In this issue of the Journal of Invasive Cardiology, Dr. Rizik and colleagues state: “The importance of the lower inflation pressures used to obtain luminal gains is underscored because of the surfeit of data, suggesting that higher inflation pressures potentially result in greater damage to the vessel wall. The reduced barotrauma to the vessel wall may eventually lead to lower restenosis rates”. We critically miss the relation with the long term and the restenosis. Finally, to understand the utility of “Cut and Stent”, we must come back to the MUSIC (or CRUISE)16,17 study to find out when the MUSIC criteria were fulfilled: at 8, 10 or 12 atmospheres? “Cut and Stent”, by improving the compliance of the vessel, may be extremely valuable now since more complex lesions will benefit from “drug-eluting stents”.

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