What is the main purpose of covered self-expanding stents?

• A. Emergent fixtures of perforation in addition to aneurysm repair
• B. Drug elution to prevent restenosis
• C. To expand only after surgical removal
• D. To occlude vessels

Answer: (A)

Covered self-expanding stents are designed to seal defects in the vessel wall while keeping the lumen open. The graft covering acts as a barrier that lines the injured area, so placing such a stent can immediately seal a perforation and, in aneurysm cases, exclude the aneurysm from circulation by creating a new, intact lumen. This is different from drug-eluting stents, which aim to prevent restenosis with medication, and from stents meant to occlude a vessel. The covered graft allows continuous blood flow through the parent vessel while preventing leakage or aneurysm-related rupture.