15.1 Coronary & Peripheral Angioplasty

Coronary & Peripheral Angioplasty

ARRT Cardiac-Interventional Procedures 2.A.1 is balloon angioplasty in coronary and peripheral arteries. The same interventional Focus of Questions used throughout 2.A applies here: anatomy and pathophysiology, indications, contraindications, imaging, access, ultrasound, equipment, complications, and closure. Coronary and peripheral balloons share physics. They do not share length, rupture stakes, or how often a drug coating stands in for a stent.

Quick Answer: Size the balloon to the vessel. A non-compliant (NC) balloon is the tool for an underexpanded stent because it delivers high pressure without growing extra diameter. Dog-boning around a tight waist concentrates stress at the edges and sets up dissection. Classic teaching treats unprotected left main (LM) PCI without surgical backup as high-risk; contemporary labs still perform selected LM PCI under heart-team rules.

Anatomy and pathophysiology the balloon actually sees

A stenosis is plaque occupying lumen — lipid core, fibrous cap, thrombus, and often calcium. The balloon does not extract plaque. It cracks and displaces it and stretches media. That is why oversize and overpressure produce dissection rather than a perfectly round channel. Coronary flow-limiting stenoses cause myocardial ischemia (stable angina, acute coronary syndrome, or a positive physiologic assessment). Peripheral lesions in the superficial femoral artery (SFA), iliac, or renal arteries cause claudication, critical limb ischemia, or renovascular hypertension. The same dog-bone physics applies; the territory a spiral dissection can cover is much longer in the SFA than in a 20 mm coronary segment.

Indications and contraindications

Indication (teaching): a stenosis causing ischemia (coronary) or a hemodynamically significant peripheral lesion the operator intends to remodel — as plain-old balloon angioplasty (POBA), as predilatation before a stent, as kissing inflation at a bifurcation, or as post-dilatation of a scaffold.

Contraindications are clinical, not an unpublished ARRT list:

• Uncontrolled bleeding, or a patient who cannot receive the antiplatelet regimen the planned intervention requires.
• Unprotected LM disease — no patent graft to the left coronary tree — is the exam-classic high-risk / relative contraindication without surgical backup. Contemporary PCI of unprotected LM exists in equipped labs with a heart team, intravascular imaging, and support devices. Teach both the classic caution and the modern reality.
• An uncrossable or undilatable calcified lesion may need atherectomy first (15.3).
• A vessel already perforated, or a lesion so thrombotic that a naked balloon will only embolize unless the operator has a distal-protection or thrombectomy plan.

Imaging, access, and ultrasound

Imaging. Orthogonal cine angiography keeps you from undersizing eccentric plaque. Intravascular ultrasound (IVUS) or optical coherence tomography (OCT) in coronaries, and peripheral IVUS, size the reference vessel and show calcium that will waist a compliant balloon. Fluoroscopy watches balloon markers. A persistent waist is information, not a dare to ignore rated burst.

Access. Coronary work: radial or femoral. Peripheral iliac/SFA: often femoral (contralateral up-and-over or ipsilateral antegrade); renal: femoral or radial. Balloon catheters travel through a guiding catheter or sheath with enough lumen; a 6 Fr coronary guide that accepted a diagnostic catheter may not accept a large peripheral balloon plus a buddy wire.

Ultrasound. Vascular ultrasound guides the arterial stick and later diagnoses hematoma, pseudoaneurysm, or occlusion. It does not replace angiographic lesion assessment.

Equipment: compliance, inflation, kissing, drug-coated balloons

Compliant balloons grow with pressure. Extra atmospheres mean extra diameter — useful for a very soft lesion or an occlusion balloon, dangerous when you chase a calcified waist.

Semi-compliant balloons are typical coronary predilatation balloons: modest growth, not a high-pressure post-dilatation tool.

Non-compliant (NC) balloons change diameter very little as atmospheres rise. That is why they post-dilate an underexpanded stent: high pressure into calcium or an unopened cell without growing past the intended size. Scenario: the delivery balloon leaves a waist in a drug-eluting stent. Do not grab a bigger compliant balloon. Grab an NC balloon sized to the stent and vessel.

Inflation and dog-boning. Inflate under fluoro. A yielding waist is the lesion cracking. Dog-boning — fat ends, pinched middle — means the balloon expanded more at the edges than at the stenosis. Oversize or overpressure at those edges is the classic edge dissection (and, if you keep going, perforation). Rated burst is a limit, not a target on a compliant balloon.

Coronary versus peripheral lengths. Coronary balloons are short (teaching order of 8–30 mm). Peripheral SFA and long iliac balloons are much longer (teaching 40–200 mm), so inflation is slower, the patient may have more ischemic pain, and a rupture or spiral dissection covers more artery. Iliac diameters are larger; rupture can empty into the retroperitoneum. Renal balloons are short and ostial-precise so you do not dissect the aorta or jail a polar branch. A long high-volume peripheral balloon also stores more energy than a 15 mm coronary balloon — different rupture risk, not the same pinhole.

Kissing balloons. At a true bifurcation, a balloon in the main branch and a balloon in the side branch are inflated together so the carina is not shoved into one lumen. Sequential “pretty” inflations are not kissing.

Drug-coated balloons (DCB). A DCB dwells, delivers antiproliferative drug (commonly paclitaxel in peripheral teaching), and comes out — no permanent scaffold. Many labs use DCB far more in peripheral arteries than in coronaries; coronary DCB is typically an in-stent restenosis or selected-lesion tool, not the default POBA substitute. A DCB is not the underexpanded-stent balloon.

Complications and closure

Complications: dissection from oversize, dog-bone, or overpressure; perforation; abrupt closure; distal embolization; no-reflow; spasm; access hematoma. A closing coronary dissection is a stent problem (15.2). An Ellis perforation is prolonged balloon occlusion and often a covered stent.

Closure is the same craft as after diagnostic work: manual compression or a vascular closure device when the stick is suitable, then a documented distal pulse and a hematoma check. Ultrasound that guided access also finds the complication.

Worked case

A mid-LAD drug-eluting stent remains with a residual waist after the delivery balloon. The operator reaches for a larger compliant balloon “to stretch it.” Stop. That balloon will dog-bone around the calcium and dissect the edges. Choose an NC balloon sized to the stent and vessel, confirm with IVUS or OCT if the lumen is still ambiguous, and post-dilate. If the waist never yields, the next tool is calcium modification (15.3), not more compliant atmospheres.

Exam traps

• Extra atmospheres on a compliant balloon are not NC post-dilatation.
• Dog-boning warns of edge dissection, not success.
• Peripheral balloons are longer; iliac rupture is retroperitoneal, not a coronary pinhole.
• Unprotected LM: teach the classic no-backup caution and that contemporary LM PCI exists.
• DCB is peripheral-heavy teaching, not a coronary stent substitute.