Occlusion of the left main coronary artery and collateral circulation via the conus branch

Vieussens' Arterial Ring: Historical Background, Medical Review and Novel Anatomical Classification

In coronary artery disease, the presence of Vieussens' arterial ring (VAR), a ring-shaped anastomosis between the conus branch of the right coronary artery with the left anterior descending artery (LAD), will allow blood flow to return to the obstructed coronary system. We have conducted a literature review, aiming to collect all the existing information about the documented VAR cases and any related pathological conditions. A total of 54 studies entered the review, including 56 patients. The mean age of the patients was 56.12 ± 16.2 years. Angina was present in 53.6% of the patients, with 7.2% of the cases being asymptomatic. Coronary artery disease outweighed (58.9%) as the patients' most frequent diagnosis. We propose a novel VAR anatomical classification, based on the sites of origin and termination of its course, with six distinct types, for a better understanding and surgical management of VAR. Type IA, originating from the conus branch and terminating in the proximal segment of the LAD was most frequently reported (51.8%). The recognition and the subsequent evaluation of the ring's anatomy and course are crucial for a customized clinical intervention. When right and left coronary angiographies fail to reveal any collateral circulation, selective conus artery catheterization should be in order. The proposed classification offers a manageable and comprehensive context for the assessment, evaluation and planning of therapeutic strategies of VAR and sets a new terminology frame for treatment guidelines.

Vieussens' arterial ring: a rare coronary variant anatomy

PURPOSE

We aimed to evaluate Vieussens' arterial ring (VAR) variants by consecutive coronary computed tomography (CT) angiography examinations.

METHODS

We retrospectively evaluated the presence of VAR in a total of 3443 consecutive coronary CT angiography examinations performed between November 2010 and January 2015. CT examinations were performed with a 64-row multidetector computed tomography (MDCT) scanner. All CT angiography images were evaluated for the presence and morphologic features of VAR subtypes. VAR variants were classified into four subgroups.

RESULTS

Eleven VAR variations (3.19‰) were identified. Type 1A was the most common VAR type (n=8), followed by Type 2 (n=2) and Type 3 (n=1). Type 1B was not detected.

CONCLUSION

Although VAR variation is less frequently detected with coronary CT angiography than in previously reported anatomic series, coronary CT angiography is quite effective to reveal VAR subtypes and other relevant cardiocoronary anomalies.

The importance of the conus artery in patients with obstructive coronary artery disease

It is well-known that collateral circulation is important in preserving ventricular functions, especially in coronary artery disease with total occlusion. The conus branch is distinct in having notable capacity of angiogenesis and arteriogenesis. We intend to emphasize the clinical importance of the conus branch by presenting two cases in which it supplied the distal regions of total occlusion.