Vieussens’ ring
Vieussens’ ring
Vieussens’ ring is an important epicardial collateral arterial connection between the conus branch of the right coronary artery (or an independent conus artery from the aorta) and the proximal left anterior descending artery (LAD).
It forms a vascular “ring” around the right ventricular outflow tract (RVOT) and proximal interventricular groove.
Anatomy & variants
- Usually involves the conus artery → anastomosis → proximal LAD.
- The conus artery may arise from the RCA or directly from the aorta (anatomical variant).
- The ring can be single or multiple small anastomoses; size and prominence vary widely.
Physiologic / clinical significance
- Acts as a natural collateral pathway supplying the LAD territory when LAD flow is compromised (chronic total occlusion or severe stenosis).
- Important in coronary chronic total occlusion (CTO) — can maintain distal perfusion and influence symptoms, viability, and revascularization strategy.
- Can be a target for interventionalists when planning retrograde CTO PCI or assessing collateral circulation.
- Rarely, a prominent Vieussens’ ring may be involved with aneurysm formation or be confused with other vascular structures on imaging.
Imaging identification
- Coronary angiography: classic way to visualize — look for a vessel from the conus region crossing to the proximal LAD.
- CT coronary angiography (CTCA): shows course and calibre well; excellent for mapping variants and planing interventions.
- Intra-procedural angiograms: can demonstrate flow direction and usefulness of the collateral during ballooning or occlusion tests.
Interventional / surgical implications
- Presence of a well-developed Vieussens’ ring can:
- Mean better myocardial perfusion distal to LAD lesions (reducing ischemia).
- Provide a retrograde collateral channel that may be usable during CTO PCI (requires experienced operators).
- When performing bypass or ligation near the conus/RVOT region, surgeon awareness is useful to avoid compromising collateral flow.
- In some revascularization planning, collaterals may affect urgency/choice of revascularization.
Key pitfalls / pearls
- Don’t confuse a large conus-to-LAD collateral with an anomalous coronary artery origin — check ostial origins carefully.
- A prominent Vieussens’ ring may be the main blood supply downstream of an occluded LAD — occluding it (surgically or inadvertently) can provoke ischemia.
- Helpful predictor of myocardial viability distal to chronic LAD occlusions; presence argues for potentially salvageable myocardium.
One-line summary
Vieussens’ ring = conus (often RCA-origin) → collateral link to proximal LAD — an anatomically variable but clinically important collateral that can preserve LAD territory perfusion and influence coronary intervention strategy.
1. Vieussens’ ring is a collateral connection between which vessels?
A. Conus (RCA or aortic) → proximal LAD
B. Obtuse marginal → PDA
C. LCx → distal RCA
D. Ramus intermedius → diagonal branches
Links conus (from RCA or independent aortic ostium) to proximal LAD — important collateral supplying LAD territory.
2. Which variant is a common origin for the conus artery contributing to Vieussens’ ring?
A. Distal LAD
B. Direct ostium from the aorta (independent conus artery)
C. Posterior descending artery
D. Left main trunk
Conus may arise from RCA or as a separate aortic ostium (independent conus artery).
3. A prominent Vieussens’ ring can:
A. Cause severe aortic stenosis
B. Replace need for aspirin
C. Provide collateral flow to distal LAD in chronic LAD occlusion
D. Always indicate coronary vasospasm
It supplies alternate flow to distal LAD when proximal LAD is occluded, preserving perfusion and viability.
4. Best angiographic way to visualize Vieussens’ ring is:
A. Left atrial injection
B. Venous phase only
C. Selective LCx injection
D. Selective conus / RCA or aortic root injection
Selective conus/RCA or aortic root injection demonstrates the conus→LAD collateral pathway.
5. In LAD chronic total occlusion, a strong Vieussens’ ring commonly:
A. Reduces ischemic symptoms by collateralizing LAD territory
B. Causes immediate infarction
C. Obviates revascularization always
D. Leads to RV failure
Collateral flow can decrease ischemia and preserve myocardium; treatment still depends on symptoms/viability.
6. Best noninvasive modality to map Vieussens’ ring anatomy is:
A. Chest X-ray
B. CT coronary angiography (CTCA)
C. Transthoracic echo
D. Abdominal ultrasound
CTCA delineates vessel course and calibre and helps pre-procedural planning.
7. Why should surgeons be cautious near RVOT when Vieussens’ ring is present?
A. It causes aortic regurgitation
B. It always increases bleeding risk
C. Injury to conus collaterals can eliminate important LAD supply
D. The ring requires routine ligation
Disruption of significant collaterals may precipitate ischemia if they supply the LAD territory.
8. In CTO PCI Vieussens’ ring may be used as:
A. Arterial closure
B. Graft conduit
C. LV assist
D. Retrograde collateral channel for crossing the CTO
Experienced operators may use it as a retrograde route to access distal CTO segments.
9. Prominent Vieussens’ ring should prompt assessment of:
A. Distal myocardial viability and LAD stenosis/occlusion
B. Pulmonary embolism
C. Mitral vegetations
D. Hepatic aneurysm
A strong collateral often indicates viable myocardium distal to LAD lesions; evaluate ischemia and revascularization needs.
10. Which is TRUE about the conus artery?
A. Always from LCx
B. May originate from RCA or directly from aorta
C. Supplies only LV
D. Never forms collaterals
Conus origin is variable; independent aortic ostium is common and relevant for collateral formation.
11. Most relevant clinical scenario for Vieussens’ ring is:
A. Isolated AF without CAD
B. Acute pericarditis
C. Chronic proximal LAD occlusion with preserved distal flow
D. Hypertrophic cardiomyopathy only
It often explains preserved distal perfusion despite proximal LAD occlusion.
12. A pitfall when seeing a large vessel near the RVOT is:
A. Mistaking for pulmonary vein
B. Mistaking for bronchial artery
C. Mistaking for aortic cusp
D. Confusing a conus collateral with anomalous coronary origin if ostia unclear
Careful ostial identification avoids mislabeling collaterals as anomalous coronary arteries.
13. Interventional risk when using Vieussens’ as retrograde channel:
A. Vessel injury/perforation or dissection of fragile collateral
B. Immediate renal recovery
C. Guaranteed success
D. Prevents arrhythmia
Collateral channels are small and fragile; retrograde use risks perforation or thrombosis.
14. If Vieussens’ ring is dominant, symptoms are often:
A. Always absent
B. Potentially milder due to collateralized flow
C. Directly causing syncope
D. Causing hyperthyroidism
Adequate collateral flow can reduce ischemic severity; clinical picture depends on balance of supply/demand.
15. Flow direction in Vieussens’ ring:
A. Always LAD→conus
B. Only venous
C. Can be antegrade or retrograde depending on pressure gradients
D. Always LCx→LAD
Collateral flow direction depends on pressure gradients; in occlusion it often runs from conus→distal LAD.
16. Which anomaly should be checked when a large Vieussens’ ring is seen?
A. PDA
B. Bicuspid aortic valve
C. Pulmonary AV malformation
D. Anomalous conus origin from the aorta
Confirm coronary ostia because an independent conus ostium is common and important to note.
17. If Vieussens’ supplies a large LAD territory, occluding it surgically could:
A. Cause ischemia/infarction of that territory
B. Improve myocardial function
C. Prevent arrhythmia
D. Always be harmless
If collateral is primary supply, its occlusion may precipitate ischemia; preserve significant collaterals when possible.
18. Which combo shows anatomy + perfusion from Vieussens’ ring?
A. Fluoroscopy alone
B. CTCA + perfusion imaging (SPECT/PET)
C. Abdominal CT
D. EEG
CTCA shows anatomy; SPECT/PET documents effective perfusion from collaterals.
19. When planning CABG, Vieussens’ ring may influence:
A. Valve choice
B. Need for pacemaker
C. Graft target selection (proximal vs distal LAD)
D. Appendectomy
If distal LAD is well supplied by collaterals, surgeons may alter graft strategy accordingly.
20. Key action when Vieussens’ ring is identified:
A. Start anticoagulation indiscriminately
B. Immediate valve replacement
C. Assume LAD is normal
D. Map coronary anatomy carefully and assess viability/revascularization plan
Careful anatomical and functional assessment is essential to guide safe and effective revascularization.
Vieussens’ Ring — 20-point Summary
| Topic | Detail |
|---|---|
| 1. Definition | Collateral connection between conus artery (RCA or aortic ostium) and proximal LAD. |
| 2. Origin | Conus from RCA or independent aortic ostium. |
| 3. Anatomy | Arcade around RVOT / proximal IV groove to proximal LAD. |
| 4. Variants | Single large vessel, multiple anastomoses, independent conus ostium. |
| 5. Role | Supplies distal LAD territory when proximal LAD compromised. |
| 6. Imaging | Best on selective angiography and CTCA. |
| 7. Perfusion | Can preserve viability distal to LAD occlusion. |
| 8. CTO PCI | Possible retrograde collateral channel (expert use). |
| 9. Surgical relevance | Avoid injuring conus collaterals during RVOT/adjoining repairs. |
| 10. Ostial ID | Confirm origins to differentiate from anomalous coronaries. |
| 11. Pitfall | Large collaterals may mimic anomalous arteries if not carefully assessed. |
| 12. Hemodynamics | Flow direction varies with pressure gradients (ante/retrograde). |
| 13. Complications | Collateral injury risks ischemia; retrograde PCI risks perforation. |
| 14. CTCA use | Pre-PCI anatomical mapping and planning. |
| 15. Perfusion correlation | Combine CTCA with SPECT/PET to confirm functional perfusion. |
| 16. Predictive value | Suggests salvageable myocardium distal to CTO. |
| 17. Interventional strategy | Influences retrograde vs antegrade approach and graft selection. |
| 18. Recognition | Look for conus→LAD crossing vessel on multiple angiographic views. |
| 19. Reporting | Document caliber, direction, and ostial origin in reports. |
| 20. Takeaway | Map and consider Vieussens’ ring in revascularization planning to avoid loss of supply. |
| No. | Question | Answer |
|---|---|---|
| 1 | What is Vieussens’ ring? | An arterial collateral loop connecting the conus branch of the RCA with the LAD. |
| 2 | Where is Vieussens’ ring located? | Around the right ventricular outflow tract (RVOT). |
| 3 | Who first described Vieussens’ ring? | Raymond de Vieussens, a French anatomist, in the 18th century. |
| 4 | What is the main clinical significance? | It provides collateral circulation in proximal LAD occlusion. |
| 5 | Which two arteries form Vieussens’ ring? | Conus branch of the RCA and proximal LAD. |
| 6 | How is it visualized on angiography? | As a collateral loop between RCA and LAD in selective injection. |
| 7 | In what percentage of people is Vieussens’ ring present? | Approximately 30–50%. |
| 8 | What is the alternate name for the conus branch? | Third coronary artery. |
| 9 | Why is it important in CABG surgery? | Preserving it can maintain myocardial perfusion during LAD grafting. |
| 10 | Which heart chamber does it encircle? | The right ventricle at its outflow tract. |
| 11 | What role does it play in acute MI? | May limit infarct size by providing collateral flow. |
| 12 | Is it more common in right or left dominant circulation? | No strong dominance correlation, but easier to see in right dominant hearts. |
| 13 | What imaging can detect it apart from angiography? | CT coronary angiography. |
| 14 | What is its embryological origin? | Persistence of anastomotic channels between early coronary buds. |
| 15 | Can it be a source of myocardial bridging? | Rarely, but the loop can run intramyocardially. |
| 16 | What does a well-developed ring suggest in chronic CAD? | Long-standing LAD stenosis with collateral recruitment. |
| 17 | Why is it sometimes called the “arterial ring of Vieussens”? | Because it forms a complete vascular loop. |
| 18 | What happens if both the RCA and LAD are proximally occluded? | The ring may be ineffective due to absence of inflow. |
| 19 | Is it considered an epicardial or endocardial vessel? | Epicardial. |
| 20 | Can it be used as a diagnostic sign for chronic ischemia? | Yes, its presence often indicates chronic LAD obstruction. |
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