Reconstruction of an Extracardiac Aortocoronary Collateral and Simulation of Selective Angiography With Multidetector-Row Computed Tomography
A 48-year-old man with familial hypercholesterolemia was admitted to our hospital with stable angina pectoris. Stress myocardial perfusion imaging showed myocardial ischemia in the inferior left ventricular wall. Coronary angiography revealed a chronic total occlusion of the proximal right coronary artery (RCA; Figure 1A and Movie I in the online-only Data Supplement). An intercoronary collateral was observed from the atrial branch of the left circumflex artery to the posterolateral branch of the RCA (Figure 1B and Movie II in the online-only Data Supplement). Contrast material filled the distal RCA retrogradely through this collateral. However, the contrast material was flushed out antegradely by the pulsatile blood flow from the native RCA toward the posterior descending artery in systole (Figure 1B and Movie II in the online-only Data Supplement); this suggested that the second collateral flowed into a site proximal to the RCA crux. Because the second collateral could not be detected during the initial angiography, multidetector-row computed tomography (MDCT) was performed, which successfully detected and visualized the extracardiac aortocoronary collateral connecting to the mid RCA just distal to the chronic total occlusion (Figure 2). Figure 3 shows the location of the collateral on each axial image. The diameter of the collateral was measured as 1.5 mm. Figure 4 shows aortography-like volume-rendered images of the entire collateral pathway. For the subsequently scheduled percutaneous coronary intervention, the appropriate catheter for selective collateral angiography was chosen after simulation with 3-dimensional routing software (Figure 5). The shape like the Judkins Right 5.0 catheter was considered optimal for selective collateral angiography with the femoral approach. All analyses were performed with a commercially available workstation (Ziostation version 18.104.22.168, Ziosoft Inc, Tokyo, Japan).
During percutaneous coronary intervention, selective angiography of the collateral was successfully performed with a 5F Judkins Right 5.0 catheter (Goodman Co, Ltd, Nagoya, Japan; Figure 6).
The most common types of extracardiac aortocoronary collaterals are those between bronchial and coronary arteries and between internal thoracic and coronary arteries.1,2 In the present case, we were unable to conclude that the collateral was derived from the bronchial artery because other independent bronchial arteries were detected.
Subepicardial insertion of extracardiac aortocoronary collaterals is typically found at sites of pericardial reflections, which allows the collaterals to enter the subepicardial layer.2 In the present case, the insertion point was at the pericardial reflection around the left atrial roof vein located behind the pericardial transverse sinus, as demonstrated in Figures 2 and 3E.3 Dewey and Dübel4 demonstrated a similar volume-rendered image of an extracardiac aortocoronary collateral to the RCA. However, in contrast to the present case, the subepicardial insertion point in their patient appeared to be at the pericardial reflection located at the top of the oblique pericardial sinus. The collateral descended along the posterior left atrial wall under the oblique pericardial sinus and then connected to the distal RCA. Selective angiography was reported to be impossible because of the small size (2.0 mm) of the collateral, despite MDCT reconstruction.4
Using MDCT, we not only identified the extracardiac aortocoronary collateral but also successfully used a simulation to determine the optimal catheter for selective collateral angiography. Although the utility of aortography to detect extracardiac aortocoronary collaterals has been reported,1 selective collateral angiography is necessary to reduce contrast volume during percutaneous coronary intervention for chronic total occlusion.
As demonstrated in the present case, transformation of data obtained from MDCT into critical images would be extremely useful for diagnosis and treatment selection in clinical practice. Communication and cooperation among cardiologists, radiologists, and radiological technologists are essential to obtain high-quality images with minimal radiation exposure and contrast volume. To the best of our knowledge, this is the first reported case of successful selective angiography of the extracardiac aortocoronary collateral with the support of MDCT simulation.
We gratefully thank the following radiological technologists for their support in image acquisition and processing: Ayami Nakamura, Erina Suehiro, Wakiko Tani, Toshinori Sekitani, Kiyosumi Kagawa, Noriyuki Negi, and Tohru Murakami.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.114.015137/-/DC1.
- © 2015 American Heart Association, Inc.