9.3 Coronary Angiography, Dominance & Projections

Coronary Angiography, Dominance & Projections

Procedures 1.A.2.a is native coronary angiography. Graft angiography is the next chapter. Here you engage native ostia, prove TIMI flow, and lay out LAD versus LCx versus RCA without turning this into the entire image-acquisition lecture.

Quick Answer: Judkins left typically seats the LM; Judkins right is clockwise-rotated into the RCA. Amplatz is more aggressive. Universal radial shapes can engage both natives. TIMI 0–3 grades antegrade flow. Eccentric stenoses lie in orthogonal views. Damping in a small RCA is a dissection warning — withdraw, do not force contrast. Spasm gets nitroglycerin (NTG), not a stent.

Catheter shapes and engagement

Judkins left (JL). Preformed curve; common femoral teaching size is JL4, with JL3.5 for a narrow aorta and JL5 (or larger) for an unfolded wide root. From the left sinus the primary curve points at the LM. A slight pull often seats the ostium. If the curve is too small, the tip points down the LAD or deep-seats; too large, it prolapses into the sinus.

Judkins right (JR). Typical JR4. Park in the right sinus and rotate clockwise so the tip lifts into the RCA ostium. Counterclockwise usually unseats. Short RCA ostia and shepherd-crook takeoffs may refuse JR4.

Amplatz left and right (AL/AR). Deeper, more aggressive secondary curves for anomalous takeoffs, dilated roots, or poor Judkins seating. More ostial trauma. Do not deep-seat an AL in the LM and power-inject.

Universal radial catheters (Tiger-type, Jacky-type, and similar): one shape that can engage both natives from the right radial. They are not magic and not forbidden on the RCA. Watch torque; they can jump from LM to RCA with a small rotation.

Engagement rules that prevent chapters of complications. Confirm a crisp aortic waveform before any cine. If the pressure damps or ventricularizes, you are too deep or the ostium is diseased — withdraw. Do not use a test puff as a substitute for a live pressure. Nonselective sinus puffs find a missing ostium (including a separate conus) without burying the tip.

TIMI flow

Thrombolysis in Myocardial Infarction (TIMI) grade is antegrade native-vessel flow, not percent stenosis.

TIMI 3 can still hide a 90% eccentric stenosis. TIMI 0 is occlusion, not slow flow. Report the grade on the culprit and the other natives.

Eccentric versus concentric stenosis

Concentric narrowing encircles the lumen; orthogonal views look similarly tight. Eccentric plaque sits on one wall; the lumen is a crescent. One projection can look 40% and the orthogonal 80%. That is why native angiography is at least two views per vessel, not a single pretty picture. Percent diameter stenosis is projection-dependent; do not let a single RAO frame talk you out of a lesion the LAO caudal just showed.

Laying out LAD versus LCx versus RCA

You already know C-arm vocabulary from image production. Use it here only to separate natives.

• LAO caudal (spider): looks into the LM bifurcation. Proximal LAD and proximal LCx peel apart. Best first left-coronary map for ostial and proximal disease.
• Cranial angulation (RAO cranial or LAO cranial): elongates the LAD and diagonals; LCx is often foreshortened or thrown off.
• Caudal angulation (RAO caudal): opens the LCx and obtuse marginals; LAD may overlap.
• RCA: LAO for ostium, vertical mid-RCA, and often the crux; RAO for mid-RCA, PDA, and PLV without overlap.

Dominance is proven on the angiogram, not assumed from the ECG. Find who gives the PDA and PLV. Right-dominant: those branches from RCA (typical adult teaching ~85%). Left-dominant: PDA from LCx. Co-dominant: split. If the RCA is small and ends before the crux, look at the LCx before you call the RCA occluded.

This section is native coronaries. Do not spend the acquisition on aorto-coronary grafts here.

Complications of diagnostic angiography

Dissection. Catheter tip, wire, or a jet against a plaque. Appears as a new flap, contrast staining, or sudden TIMI drop. Stop injecting. Maintain wire access if a wire is already true-lumen; emergency PCI or surgery is physician-directed.

Spasm. Catheter-tip irritation, especially RCA and radial access. Focal, smooth, and often at the tip. Intracoronary NTG (physician-directed) distinguishes spasm from fixed stenosis. Do not stent a vessel that opened with nitrate.

Embolization. Air from a dry manifold, thrombus from the catheter, or plaque debris. Air: ischemia, often inferior, can degenerate to VF — stop, 100% oxygen, supportive care. Thrombus: downstream cutoff.

Ostial damage from deep engagement. A deeply seated JL or Amplatz in a short LM can dissect the LM or exclusively inject the LAD, leaving LCx unopacified and creating a false LCx occlusion. A deep JR in a small RCA is the classic damping scenario.

Scenario: damping in a small RCA

JR4 clockwise-engages a small RCA. The aortic waveform damps; diastolic pressure falls; the patient may feel pressure or the ST segment in II, III, and aVF drifts. Do not fire a cine to document engagement. Withdraw until a true aortic tracing returns. A gentle nonselective puff can confirm ostial location. If a safe position is restored and the vessel looks pinched at the tip, NTG treats spasm. Persistent flap or staining is dissection, not spasm. Deep seating is not a substitute for a smaller or differently shaped catheter.

Worked case

Radial universal catheter seats the LM easily. LAO caudal spider shows a moderate ostial LCx. RAO cranial looks almost normal in the LCx because the plaque is eccentric. Add RAO caudal: the LCx is 80% and TIMI 2 (complete but delayed). RCA is small; JR4 damps. Withdraw, do not inject, switch shape or take a nonselective sinus shot. PDA arises from LCx — left-dominant. Native angiography is finished only when both ostia are seen, TIMI is graded, orthogonal views exist, and the PDA origin is named.

Exam traps

• Damping in a small RCA is not a green light to power-inject.
• TIMI 2 is delayed complete filling, not occlusion (TIMI 0) and not normal (TIMI 3).
• Eccentric disease needs a second projection.
• Amplatz is not the atraumatic default.
• This chapter is natives, not grafts.
• Spasm that resolves with NTG is not a stent indication.