Small vessel angioplasty - specificities and results

Technical specificities of small-vessel coronary angioplasty gather all the potential difficulties of percutaneous coronary interventions (PCI): guiding the guide-wire, crossing the lesion with the catheter, stenting due to frequently high tortuousities of the vessel up-stream to the lesion and the need for high pressure to deploy the stent. Even if the post-PCI angiographic result is good, the long-term follow-up is affected by a higher incidence of restenosis or in stent sub-acute closure (1).

Once medical treatment has failed, the 2 remaining questions concern the true diameter of the vessel (pseudo-small artery due to long, large and eccentric plaque narrowing a “normal” artery) and the lesion length. The longer the lesion is and the smaller the artery will be, and the higher will be the restenosis rate. IVUS appears to be a very attractive tool providing interesting information regarding whether the vessel is a true or a pseudo small-vessel, and enable an optimal result after PCI capable of obtaining the largest possible cross sectional areas (2).

Short lesions can benefit from short stenting strategies whereas stenting of long lesions is commonly complicated by a prohibitive rate of restenosis. An alternate solution is balloon angioplasty associated with spot stenting in the worst dilated site (3). Nevertheless, in cases of short stenting on small-vessels, the role of non drug eluting stents remains controversial: SISA, ISART-SMART and COAST trials showed a non significant difference in restenosis rates when comparing the stent and balloon approach. In opposite, RAP and BE-SMART trials have showed a benefit to stenting.

Small-vessel PCI is associated with  a high rate of acute complications implicating both mechanical difficulties and microembolisation from the lesion site. In this setting, IIb/IIIa platelets receptor blockades have demonstrated a significant decrease in post balloon and stent angioplasty. Nevertheless, the cost-benefit relationship has to be taken into account because small-vessels often supply blood to a small portion of myocardium and thus the clinical benefit of these increasing costs has to be discussed.

Drug eluting stents (DES) with antiproliferative agents emerge as an important new technology in the setting of small-vessels PCI. DES improve the long term results of PCI knowing that the restenosis rate is not so astonishing then larger arteries (restenosis rate when diameter < 2.3 mm: 19% as compared with 1.9% when diameter > 3.0 mm). In the small-vessel sub-group of patients, recommendations on the optimal deployment of the stent should be maintained to decrease the likelihood of restenosis.

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.