Direct Stenting Versus Predilatation and Stenting
David R. Holmes Jr.
Stenting strategies have evolved substantially during the time that stents have become the dominant percutaneous revascularization approach for the treatment of coronary artery disease. Initially, predilatation prior to stent deployment was not only the norm but was the requisite. This was the result of several factors (Table 8.1):
The initial stent approval process was for a bailout indication—accordingly, all patients receiving a stent had undergone prior conventional percutaneous transluminal coronary angioplasty (PTCA).
The initial first-generation stent technology was bulky, rigid, and inflexible with a high profile, so that adequate predilatation was required to optimize even the chance of crossing the lesion during elective cases.
Some early stent generations had a significant incidence of stent dislodgement from the delivery balloon; to minimize that, predilatation commonly was used.
Many of the randomized protocols for the evaluation of stents required predilatation before stenting, and those protocols often were followed after the randomized clinical trials were concluded. This requirement was carried out as recently as the drug-eluting stent (DES) randomized clinical trials.
Predilatation was undertaken to avoid damaging the stent, including drug-eluting stents, if the lesion could not be crossed easily without predilatation.
In the case of rigid or calcified stenosis, predilatation was necessary because early stent balloons were under low pressure; if a rigid lesion could not be dilated using the stent balloon, then an incompletely deployed stent would result. Rarely, the balloon could not be withdrawn from the stent. This was sometimes confounded by the fact that trying to dilate a rigid lesion using the stent balloon resulted in balloon rupture and more arterial damage.
Predilatation helped to correct errors in underestimating vessel size because of poor flow at baseline prior to treatment and the subsequent selection of the wrong stent size.
Against the trend of routine predilatation, investigators began to consider direct stenting. Several potential reasons encourage such a strategy (Table 8.1). Economic advantages may accrue, because a predilatation balloon is not required. In addition, procedural time might be shorter, with less contrast use. Another possible advantage is the decreased embolization of plaque material that might occur during predilatation and a subsequent decrease in arterial injury. If the initial arterial injury can be decreased, the direct stenting procedures may result in decreased restenosis rates. Finally, direct stenting facilitates covering the entire injured segment with a DES, an extremely important requirement in the use of DESs.
Against this background of advantages and disadvantages, multiple registries and randomized trials of direct stenting have been undertaken (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13).
These studies have looked at multiple clinical and angiographic endpoints. In the largest, Wilson et al. (7) evaluated the outcome in 777 patients treated with direct stent implantation versus 3,176 patients treated with predilatation
and then stenting during the period from 1996 to 1999, which represented early-generation stent technology. In this study, procedural success rates were not different between direct stenting and predilatation (96.3% versus 96.4%). Using multivariate analysis, no difference was observed between the two groups in in-hospital mortality, in-hospital myocardial infarction (MI), or in long-term clinical outcome (Fig. 8.1). The only significant differences were a reduction in procedural duration, and decreased contrast, balloon, and wire use. Wilson’s studied revealed, however, that in 5% of the time when direct stenting was initially attempted, crossover was required. With current stent technology, failure to deliver the stent without predilatation may decrease; this may be counterbalanced by attempting interventions on longer, more distal, and diffuse disease, which might mandate more predilatation. Smaller registry series have documented somewhat variable results (1,11,16,17); in some subgroups, for example acute coronary syndromes including MI, direct stenting may be associated with improved TIMI flow rates and a reduction in the elevation of cardiac biomarkers. In addition, vein-graft lesions should be treated with direct stenting to decrease the chance of distal embolization, although current distal protection devices make this less crucial. In general, the observational studies have not shown a reduction in restenosis with direct stenting using bare metal stents (BMSs) versus predilatation followed by stent implantation.
and then stenting during the period from 1996 to 1999, which represented early-generation stent technology. In this study, procedural success rates were not different between direct stenting and predilatation (96.3% versus 96.4%). Using multivariate analysis, no difference was observed between the two groups in in-hospital mortality, in-hospital myocardial infarction (MI), or in long-term clinical outcome (Fig. 8.1). The only significant differences were a reduction in procedural duration, and decreased contrast, balloon, and wire use. Wilson’s studied revealed, however, that in 5% of the time when direct stenting was initially attempted, crossover was required. With current stent technology, failure to deliver the stent without predilatation may decrease; this may be counterbalanced by attempting interventions on longer, more distal, and diffuse disease, which might mandate more predilatation. Smaller registry series have documented somewhat variable results (1,11,16,17); in some subgroups, for example acute coronary syndromes including MI, direct stenting may be associated with improved TIMI flow rates and a reduction in the elevation of cardiac biomarkers. In addition, vein-graft lesions should be treated with direct stenting to decrease the chance of distal embolization, although current distal protection devices make this less crucial. In general, the observational studies have not shown a reduction in restenosis with direct stenting using bare metal stents (BMSs) versus predilatation followed by stent implantation.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
