stent malapposition
Incomplete stent strut contact with the vessel wall, detected by intravascular imaging and associated with increased thrombosis risk.
Full Definition
Stent malapposition refers to the incomplete apposition of stent struts against the coronary artery wall, creating a gap between the stent and vessel surface that exceeds the expected strut thickness plus polymer coating. This condition can be acute (present immediately post-deployment) or late (developing during follow-up due to vessel remodeling or thrombus resolution). Malapposition is optimally detected using intravascular ultrasound or optical coherence tomography, which can precisely measure the distance between stent struts and vessel wall. The clinical significance includes increased risk of stent thrombosis, particularly when malapposition involves large vessel segments or areas of high shear stress. Treatment may involve high-pressure balloon post-dilatation or additional stent deployment depending on the extent and location.
Usage
Usage note: Distinguish between acute and late malapposition. Quantify the gap distance when using intravascular imaging.
In Context
- "OCT imaging revealed significant stent malapposition in the proximal segment requiring high-pressure balloon post-dilatation." — Intravascular imaging report
- "Late stent malapposition was identified during follow-up OCT, likely related to late thrombus resolution." — Follow-up catheterization note