[Coronary recanalization: rationale for stents].
Coronary stenting is a technique complementary to coronary angioplasty, because it is successful in the management of the two major limitations of conventional balloon dilation, i.e. the acute or threatened closure and the restenosis. The currently available intracoronary stents are far from being ideal, mainly for their thrombogenicity. During abrupt closure, the bailout stenting has, in most of the cases, offered a valuable alternative to emergency coronary artery bypass surgery. The major complications after stent insertion are the result of an inadequate stent placement, of persistence of intra and/or poststent obstruction and of the ineffective anticoagulant therapy. The mechanical support (scaffolding) provided by the stent after dilation significantly reduces the amount of elastic recoil, and, improving laminar flow, eliminates arterial wall shear stress that may contribute to an increase in intimal thickening. Moreover, the reduction of arterial cyclical stretching may reduce the rate of neointimal proliferation. By sealing the exposed subintimal spaces, stents may minimise the formation of local thrombi, and thus also limit their later organization and fibrous conversion into part of the restenotic lesion: two recently completed randomized trials (STRESS and BENESTENT) confirm the lower rate of restenosis in patients treated with single stent placement in de-novo lesions as compared with standard balloon angioplasty. The mechanism of stent benefit in reducing restenosis rate seems to be the wider initial lumen, which can accommodate a greater degree of intimal hyperplasia. In the near future, the improvements of the blood and tissue compatibility of the stents, may allow easier management.(ABSTRACT TRUNCATED AT 250 WORDS)
Vassanelli
C
C
Cattedra e Divisione Clinicizzata di Cardiologia, Università degli Studi, Verona.
Menegatti
G
G
Molinari
J
J
Loschiavo
I
I
Zardini
P
P
D003327:Coronary Disease / Q000601:surgery*; D006801:Humans; D009204:Myocardial Revascularization / Q000295:instrumentation*; D015607:Stents
Ricanalizzazione coronarica: il razionale degli stent.