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4781080 
Journal Article 
Coronary stent malapposition 
Mansour, H; Dupouy, P; Pernes, JM 
2012 
0 
Sang Thrombose Vaisseaux
ISSN: 0999-7385 
24 
6 
279-292 
WOS:000311528600004 
Coronary stent malapposition



Stent malapposition (SM), also known as incomplete stent apposition, is defined by a separation of at least one stent strut from the intimal surface of the arterial wall with evidence of blood behind the strut without involvement of side branches. It is a poorly understood phenomenon probably underestimated by angiography, and its prognostic impact remains not fully clarified (is it a real risk factor for acute or late stent thrombosis or just an "innocent bystander"?). Stent malapposition can be acute, occurring at the time of stent implantation, or late, detected during follow-up and the underlying mechanisms of both types are different. The acute or immediate stent malapposition usually happens due to a complex anatomy (e.g total occlusion, aneurysm, long lesion, calcification, etc.) or due to an operator technical deficiency (e.g poor assessment of the real diameter, too low stent deployment pressure, etc.). The pathophysiological mechanisms of late stent malapposition are the delayed dissolution of the thrombus especially in case of acute myocardial infarction, and positive remodelling of the treated vessel possibly secondary to local hypersensitivity reaction associated with the polymer in the drug-eluting stents, the fact that may explain why malapposition was noted much more often with this type of stents compared to the bare metal stents. The diagnosis of this phenomenon can be made only through the use of intravascular imaging techniques, the Optical Coherence Tomography (OCT) which proved to be more efficient, because of its higher spatial resolution, and the intravascular ultrasound (IVUS),



Its prevention depends mainly on the strict adherence to technical requirements during angioplasty especially in certain clinical and anatomical situations which carry a high incidence of malapposition. On these situations, we may find a chance to the self expandable nitinol stents to be a better alternative to the balloon mounted stainless steel or cobalt chromium stents due to its ability to expand by time to be well opposed to the wall even if further changes of the vessel size or thrombus dissolution occurred especially in cases of acute myocardial infarction. 
coronary stent malapposition; stent thrombosis; acute myocardial infarction; self-expandable stents