Number 34, 2007
Picture my heart!

Multislice computed tomography coronary angiography before percutaneous recanalization of chronic total occlusions

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N.R. Mollet^a,b, N. Van Pelt^a,b, G. Sianos^b, W.B. Meijboom^a,b, F. Cademartiri^a,b, P.J. de Feyter^a,b
aDepartments of Radiology ^bCardiology, Erasmus Medical Center, Rotterdam, The Netherlands
Correspondence: Dr Nico R. Mollet, Room Ca-229a, Department of Radiology, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands. Tel: +31 10 463 4044; fax: +31 10 463 4033; e-mail: n.mollet@erasmusmc.nl

Case report
A 64-year-old man with persistent symptoms of typical angina pectoris and a positive exercise test underwent diagnostic conventional coronary angiography to evaluate the presence and extent of coronary artery disease. Selective catheterization of the left coronary artery showed retrograde filling of the right coronary artery (RCA) supplied by a large collateral originating from the distal left anterior descending coronary artery (LAD). The operator was not able to catheterize the RCA, which suggested an ostial occlusion (Figure 1). Multislice computed tomography (MSCT) coronary angiography was performed using a 64-slice computed tomography (CT) scanner (Sensation 64, Siemens Medical Solutions, Forchheim, Germany). The CT scan showed a large calcified plaque at the ostium of the RCA and confirmed the presence of a totally occluded RCA with good collateral filling (Figure 2a). In addition, the collateral originating from the distal LAD was well visualized throughout its course to the mid part of the RCA (Figure 3a). The patient was scheduled to undergo percutaneous recanalization of the RCA on the basis of the conventional and CT coronary angiography findings. During this procedure, the location of the large calcified plaque in the ostium of the RCA, as seen on cardiac CT, was used to guide cannulation of the RCA. The proximal RCA lesion was then successfully crossed and treated with a short drug-eluting stent (Figure 2b). No procedure-related complications occurred.

Discussion
Chronic total occlusions are found in approximately 50% of patients with significant coronary artery disease. The majority of patients with such occlusions are either treated medically or referred directly for coronary bypass surgery. An attempt at percutaneous recanalization is usually performed in the absence of characteristics of chronic total occlusion that are known to be adverse predictors of a successful outcome, such as an occlusion length greater than 15 mm and the presence of calcifications in the occluded vessel [1,2]. MSCT coronary angiography allows reliable evaluation of coronary plaque morphology [3–6]. MSCT has several advantages in the assessment of chronic total occlusions, when compared with conventional angiography: it does not require selective catheterization to enhance the coronary lumen, coronary calcifications are easily detected, and its 3-dimensional nature allows accurate measurements of length that do not suffer from calibration limitations, foreshortening, or absence of collateral filling as occurs with conventional angiography [7].
Performance of MSCT coronary angiography may optimize the selection of patients for attempted percutaneous recanalization of chronic total occlusions. Moreover, as this case report illustrates, additional information such as anatomical landmarks may be helpful in the treatment of chronic total occlusions.

Summary
Multislice computed tomography coronary angiography provides important additional morphologic characteristics of chronic total occlusions when compared with conventional diagnostic coronary angiography. This may lead to optimized selection of patients referred to undergo percutaneous recanalization, or to refinement of the optimal percutaneous intervention strategy.

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