RCA Ostium Vulnerability to Iatrogenic Dissection
The RCA ostium is more vulnerable to iatrogenic dissection because it is located along the right anterior convexity of the ascending aorta, where dissections propagate upward more easily into the aortic wall. 1, 2
Anatomical Basis for Increased Vulnerability
The anatomical positioning of the RCA ostium creates a unique mechanical disadvantage during catheter manipulation:
The RCA ostium sits on the convex anterior surface of the ascending aorta, which provides a natural pathway for dissection planes to extend upward into the aortic wall rather than being contained within the coronary vessel 1, 2
The histological composition of the ostial region is rich in smooth muscle cells and elastic fibers (resembling aortic tissue more than coronary tissue), which may facilitate dissection propagation between vessel layers 2
This anatomical arrangement contrasts with the left main coronary artery, which does not share the same geometric relationship with the ascending aorta 1
Mechanism of Dissection Propagation
The vulnerability is compounded by procedural factors:
Catheter-induced trauma at the RCA ostium creates an intimal tear that can retrograde extend into the ascending aorta due to the favorable anatomical plane along the anterior convexity 1
Contrast injections after initial injury actively propagate the dissection by forcing contrast medium into the false lumen, driving the dissection plane further into the aortic wall 1
The dissection can extend extensively to involve the ascending aorta, aortic arch, supra-aortic vessels, and even the descending aorta in severe cases 1
Clinical Significance and Catastrophic Potential
The consequences of RCA ostial dissection can be life-threatening:
Extension of the intimal flap toward the aortic valve can cause acute aortic regurgitation, hemopericardium, and cardiac tamponade 1
Dissections extending several centimeters into the ascending aorta or continuing to propagate require emergency cardiac surgery 1, 2
While the overall incidence is rare (less than 4 per 10,000 coronary angiographies and less than 2 per 1,000 PCIs), the RCA ostium represents the most common site for this complication during coronary interventions 1, 3
Prevention Strategies
Understanding this vulnerability informs preventive technique:
Gentle catheter manipulation with appropriate catheter selection prevents dissection regardless of catheter type 3, 2
Switch to alternative catheter shapes early when standard approaches fail rather than persisting with forceful manipulation 3, 2
If dissection occurs, immediately cease contrast injections to prevent propagation of the dissection plane 1, 2
Emergency coronary stenting at the ostium can seal the entry point and prevent further aortic extension in localized dissections 1, 4, 5, 6