15.2 Coronary & Peripheral Stent Placement
Key Takeaways
- Bare-metal stents are a metallic scaffold only; drug-eluting stents add a polymer and an antiproliferative drug, and historically needed longer dual antiplatelet therapy than bare-metal stents.
- Contemporary dual antiplatelet duration after coronary stenting is protocol-based, not a single universal number, but dual antiplatelet therapy after a coronary drug-eluting stent is not optional.
- Coronary stents are typically balloon-expandable; many peripheral stents are self-expanding nitinol, while balloon-expandable stents are chosen when ostial precision matters (iliac, renal).
- Covered stents bail out perforation; IVUS or OCT diagnoses underexpansion, malapposition, geographic miss, and edge dissection — underexpansion is treated with a non-compliant balloon, not a bigger compliant guess.
- High-flexion zones (common femoral, popliteal) risk stent crush and fracture and are often avoided as primary landing zones.
Coronary & Peripheral Stent Placement
ARRT Cardiac-Interventional Procedures 2.A.2 is stent placement in coronary and peripheral arteries, still sitting on the interventional Focus of Questions: anatomy and pathophysiology, indications, contraindications, imaging, access, ultrasound, equipment, complications, and closure. A stent is a scaffold left behind after the balloon of 15.1. The exam cares which family you deployed, whether it is fully expanded against the wall, and what happens if you land it in a hinge point.
Quick Answer: Drug-eluting stents (DES) add a polymer and an antiproliferative drug to a metallic scaffold and historically needed longer dual antiplatelet therapy (DAPT) than bare-metal stents (BMS). Contemporary DAPT is protocol-based. Coronary stents are typically balloon-expandable; many peripheral stents are self-expanding nitinol. Covered stents bail out perforation. Underexpansion is an IVUS/OCT diagnosis treated with an NC balloon. Avoid primary stenting of high-flexion common femoral and popliteal zones because of crush and fracture.
Anatomy, pathophysiology, indications, contraindications
The pathology is the same plaque 15.1 cracked, plus the recoil and dissection POBA leaves behind. A stent scaffolds the lumen, tacks dissection flaps, and — with a DES — delivers drug to limit neointimal hyperplasia. Indications: flow-limiting coronary stenosis the operator will scaffold (including after a dissection or elastic recoil), and peripheral lesions in territories where a stent is the planned therapy (ostial iliac, some SFA, renal ostia). Contraindications include inability to take required antiplatelets after a coronary DES, an untreated perforation you have not sealed, a vessel too small for the smallest available scaffold, and — for peripheral work — landing a rigid stent in a high-flexion zone when a balloon or DCB strategy is still available. Unprotected LM cautions from 15.1 still apply when the scaffold is going into the LM itself.
BMS versus DES, and DAPT teaching
A BMS is metal only (stainless steel or a cobalt-chromium / platinum-chromium alloy in modern teaching). Restenosis from neointima is higher. Historically DAPT could be shorter than after DES (classic teaching often contrasted about 1 month after BMS with a much longer DES prescription).
A DES is a metallic scaffold plus a polymer plus an antiproliferative drug (everolimus, zotarolimus, sirolimus-family agents in current coronary teaching; paclitaxel appears in some peripheral and older coronary platforms). The drug lowers restenosis. Historically DES needed longer DAPT than BMS because delayed endothelialization raised stent-thrombosis risk if antiplatelets stopped early.
Contemporary DAPT is protocol-based, not a single number you should treat as an unpublished ARRT cutoff. High-bleeding-risk protocols with newer DES can be shorter than the classic 12-month coronary DES story; ACS protocols are often longer. The exam-stable facts: DES historically longer DAPT than BMS, DAPT after a coronary DES is not optional, and the duration comes from the lab protocol / physician order, not from whether a closure device was used.
Balloon-expandable versus self-expanding, covered stents
Coronary stents are typically balloon-expandable: crimped on a balloon, expanded to a chosen diameter, and they stay that size. That is why NC post-dilatation can still improve an underexpanded coronary stent.
Peripheral stents are often self-expanding nitinol. They are constrained in a delivery sheath, then spring toward a labeled diameter, which is useful in tapering SFA segments and in vessels that change caliber with pulsatility. Balloon-expandable peripheral stents are chosen when ostial precision matters — common iliac and renal ostia — because you can place the edge exactly. Self-expanding stents can still jump or miss an ostial landing if you unsheath carelessly.
Covered stents (PTFE or similar membrane over a metallic scaffold) are the perforation bailout: they seal an Ellis perforation or a ruptured iliac, and they can treat some aneurysms or fistulas. They are not first-line for garden-variety SFA stenosis. Coronary covered stents need a large enough guide and rapid availability; the first move in a blowing perforation is still a prolonged balloon occlusion while the covered stent is opened.
Sizing, imaging, and the named failure modes
Size to the reference vessel, not to the tightest cine frame of an eccentric plaque. Overlap adjacent stents enough to avoid a gap, not so much that you create a rigid hinge. Geographic miss: the stent does not cover the whole diseased or balloon-injured segment — a residual shoulder that restenoses. Underexpansion: the stent never reached the intended diameter (calcium, undersized balloon, low pressure). IVUS/OCT make this diagnosis; angiography can hide it. Treat underexpansion with an NC balloon, not a larger compliant guess. Malapposition: struts are not against the wall (undersizing, taper, or thrombus that later dissolves). Edge dissection: a flap at the stent end from geographic miss, dog-boning of the delivery balloon, or an NC balloon that overhangs. Jailing a side branch: the stent crosses a side-branch ostium and may compromise it — expected at some bifurcations, not the goal of every deployment.
Imaging. Cine documents TIMI flow and residual stenosis. IVUS/OCT confirm expansion, apposition, geographic coverage, and whether a side branch is jailed. Peripheral DSA plus IVUS do the same job in iliac and SFA work.
Access and ultrasound. Coronary DES: radial or femoral, same ultrasound-guided stick as 15.1. Peripheral self-expanding systems often need larger sheaths; confirm sheath French size before you open the device. Ultrasound still guides the stick and finds the hematoma after a 7–8 Fr peripheral sheath.
Peripheral crush, fracture, and flexion zones
Nitinol is flexible, not immortal. Repeated bending at the common femoral artery (hip flexion) and popliteal artery (knee flexion) produces stent fracture and crush. Those zones are often avoided as primary stent landing zones; operators prefer balloon or DCB strategies, or they stent adjacent segments and leave the hinge unstented. External compression (inguinal ligament, Hunter’s canal) is the same idea. A crushed iliac or SFA stent is a reintervention problem, not a success because “something metal is there.”
| Stent family | Typical territory | Key limitation |
|---|---|---|
| Coronary BMS | Selected coronaries when DAPT must be short or DES is unavailable | Higher restenosis than DES |
| Coronary DES | Workhorse coronary PCI | Historically longer DAPT; thrombosis if antiplatelets stop early |
| Balloon-expandable (bare or covered) | Coronaries; ostial iliac / renal precision | Less forgiving in flexion; covered versions for perforation |
| Self-expanding nitinol | SFA and other peripheral segments that change caliber | Jump on unsheathing; fracture/crush in flexion zones |
| Covered stent | Coronary or peripheral perforation, selected aneurysm/fistula | Thrombosis, side-branch coverage, larger delivery system |
Complications and closure
Stent thrombosis (especially if DAPT is interrupted after a coronary DES), geographic miss and restenosis, underexpansion, malapposition, edge dissection, jailed side branch, no-reflow, perforation requiring a covered stent, and peripheral fracture. Access-site bleeding is worse after a large peripheral sheath and after DAPT plus anticoagulation.
Closure: manual compression or a vascular closure device when anatomy allows. DAPT after a coronary DES continues at home — a closure device does not cancel antiplatelets. Document the distal pulse; ultrasound the groin if a hematoma grows on DAPT.
Worked case
An SFA nitinol stent is proposed for a lesion that sits directly behind the knee in the popliteal artery. That is a flexion-zone landing. Prefer a DCB or a balloon strategy, or stent above and below the hinge. If a coronary DES is deployed and IVUS shows a waist inside the stent, that is underexpansion — NC balloon, not a second overlapping DES to “cover” a mechanical problem. If dye exits the vessel, a covered stent is the seal, after a balloon has tamponaded the hole.
Exam traps
- DES historically longer DAPT than BMS; contemporary duration is protocol-based, not optional.
- Coronary = typically balloon-expandable; peripheral = often self-expanding nitinol.
- Covered stents are for perforation, not routine SFA disease.
- Underexpansion is IVUS/OCT plus NC balloon.
- Common femoral and popliteal are fracture zones, not preferred stent beds.
Which statement BEST describes bare-metal versus drug-eluting stents and dual antiplatelet teaching for the R.T.(CI)?
Which description BEST matches typical coronary versus peripheral stent mechanics?
During PCI, dye exits the vessel (perforation). Separately, an operator proposes a primary nitinol stent directly behind the knee. Which pairing is CORRECT?