Angiographic Restenosis After Myocardial Bridge Stenting: A Comparative Study With Direct Stenting of De-Novo Atherosclerotic Lesions

Abstract

SUMMARYData on restenosis after stent implantation in myocardial bridges (MB) are very limited. Six-month angiographic results for 12 symptomatic patients who underwent stent implantation for myocardial bridges were compared retrospectively with those of 39 patients who underwent direct stent implantation for de novo atherosclerotic lesions in the left anterior descending artery. Diameter stenosis decreased from 69 ± 8% to 4 ± 5% in the MB group and from 79 ± 8% to 7 ± 6% in the control group after stent deployment. Systolic narrowing was abolished in all patients with MB. In follow-up, quantitative angiography revealed late loss of 1.8 ± 1.3 mm in the MB group and 0.9 ± 0.9 mm in the control group (P = 0.025). The in-stent restenosis rate was also higher in the MB group compared to the control group (67% versus 28%; P = 0.037). Despite favorable immediate results, stent implantation in MBs may not be promising because of the higher in-stent restenosis rate compared to stenting in de novo atherosclerotic lesions. ( A myocardial bridge (MB) is an anatomical variation in which a part of a coronary artery (mostly left anterior descending artery (LAD)) courses under a segment of myocardium that compresses the lumen during systole despite a normal appearance during diastole. The reported incidence of MB varies over a wide range according to the method of diagnosis, changing from 0.5 to 2.5% in angiographic studies to 15 to 85% in autopsy series.1-3) Although known as a benign and asymptomatic condition in a majority of the patients, MBs may cause angina, myocardial ischemia, infarction, life-threatening cardiac arrhythmias, and even sudden cardiac death. [4][5][6][7][8] The clinical management of patients with symptomatic MB is not well established. On the basis of previous pathophysiological and clinFrom the

Ausência de arteriosclerose na porção intramiocárdica das artérias coronárias

“…This finding was corroborated by other studies, including pharmacological stents [41,42]. It is speculated that the in-stent restenosis, which was diffuse in most patients, may be due to vasoactive substances released from the vessel wall, squeezed between the stent and the myocardium, at each contraction [40]. It seems that the stent implantation, at least with metallic stents, should be avoided in myocardial bridges.…”

“…In patients that do not respond to medical therapy, surgical revascularization or stent implantation are the options. Even though coronary stent is capable of suppressing ischemic symptoms, there is a high rate of in-stent restenosis with stents implanted in segments with myocardial bridge [40]. This finding was corroborated by other studies, including pharmacological stents [41,42].…”

Coronary myocardial bridge constitutes a risk: But how to manage it?

“…In unresponsive patients coronary by-pass surgery or stenting are the options. Although coronary stenting was shown to abolish ischemic symptoms, we found a high rate of in-stent restenosis with bare metal stents deployed in segments with MB [6]. This finding was supported by other studies including drug eluting stents [7,8].…”

Drug eluting stents may not be the answer for myocardial bridges

“…However, bare metal stents are associated with a high restenosis rate, which has been documented as 46-67% [3,9]. Restenosis process in MB behaves differently in comparison with conventional cases.…”

“…On one hand, it International Journal of Cardiology 117 (2007) e76 -e78 www.elsevier.com/locate/ijcard seems it occurs in the first weeks after the PCI [3]. Besides this, the pattern is predominantly proliferative [9]. Additionally, the mechanism may also have special features: the persistence of external compression within the MB that might result in increased shear stress may potentially induce a stimulus for intimal proliferation; the external compression may also cause a collapse of the stent in those cases of incomplete stent expansion due to low inflation pressures, as reported by Haager [3]; it has been speculated that vasoactive substances released by compression of the vessel wall between the expanded stent and the contracting muscle might also play a role in the restenosis process; finally, stent length in these cases is longer than in conventional cases [3].…”