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[Coronary recanalization: rationale for stents]
C Vassanelli1, G Menegatti, J Molinari
1Cattedra e Divisione Clinicizzata di Cardiologia, Università degli Studi, Verona.
Insights
Coronary stenting complements angioplasty by reducing acute closure and restenosis. While stents improve outcomes, their thrombogenicity remains a challenge, with ongoing research focused on better blood and tissue compatibility.
Area of Science:
- Cardiovascular medicine
- Interventional cardiology
- Biomaterials science
Context:
- Coronary stenting is an adjunct to coronary angioplasty, addressing limitations like acute closure and restenosis.
- Current intracoronary stents face challenges, primarily thrombogenicity.
- Bailout stenting serves as an alternative to emergency bypass surgery for abrupt closure.
Purpose:
- To evaluate the role and efficacy of coronary stenting in managing coronary artery disease.
- To understand the mechanisms by which stents reduce restenosis.
- To highlight the complications and future directions in coronary stenting.
Summary:
- Stenting provides mechanical support, reducing elastic recoil and arterial wall shear stress, which may decrease neointimal proliferation.
- Stents minimize thrombus formation by sealing exposed subintimal spaces, limiting lesion organization and fibrous conversion.
- Randomized trials (STRESS, BENESTENT) show lower restenosis rates with stenting compared to balloon angioplasty for de novo lesions, likely due to a wider initial lumen.
- Complications stem from inadequate placement, persistent obstruction, and ineffective anticoagulation.
Impact:
- Coronary stenting has significantly improved the management of coronary artery disease, offering a valuable alternative to surgery.
- The mechanical scaffolding effect and improved lumen diameter contribute to reduced restenosis rates.
- Future advancements in stent biocompatibility promise easier clinical management and potentially further improved patient outcomes.
Abstract:
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)