CT Coronary Angiography-Guided Percutaneous Coronary Intervention for Chronic Total Occlusion Combined with Retrograde Approach

ABSTRACT: Percutaneous coronary intervention was performed for chronic total occlusion (CTO) of the right coronary artery (RCA) in a 55-year-old man. CT coronary angiography (CTCA) with a 64-slice scanner showed a large calcified plaque at the entrance to the CTO. A stent that had been implanted at the RCA ostium 10 years earlier was angled toward a side branch, suggesting that the guidewire would not reach the true lumen via the antegrade approach. Therefore, we attempted the retrograde approach via a septal collateral with the kissing wire technique. However, the guidewire failed to cross the CTO because of obstruction by the implanted stent. We next attempted the controlled antegrade and retrograde subintimal tracking technique and 2 stents were successfully deployed. In this patient, CTCA provided useful information for management of a difficult CTO.

J INVASIVE CARDIOL 2012;24(1):E5–E9

Key words: CART technique, CTCA, stenting

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Recently, several new imaging methods have become available for the evaluation of patients with known or suspected coronary artery disease (CAD).¹ For example, introduction of multidetector-row computed tomography (MDCT) has made noninvasive imaging of the coronary arteries possible. CT coronary angiography (CTCA) allows noninvasive evaluation of the coronary arteries and is likely to become important in the diagnosis of CAD. CTCA is also useful for planning invasive cardiac procedures, particularly complex percutaneous procedures, including the treatment of chronic total occlusion (CTO) and bifurcation stenting. CTO is still difficult to treat by percutaneous coronary intervention (PCI), although advances in equipment and techniques have led to an increase of the primary success rate. Adopting the retrograde approach can improve the success rate of PCI for CTO, especially in cases where the antegrade approach has failed.⁸ Improvement of the long-term prognosis by successful PCI for CTO has also been reported.⁴ Here we report a case of CTO treated by the retrograde approach in which pre-procedural CTCA was useful for deciding on the method of percutaneous revascularization.

Case report. A 55-year-old male with hypertension and diabetes was hospitalized with poorly controlled typical angina pectoris in July 2008. He had a history of PCI in the right coronary artery (RCA) and coronary artery bypass grafting in 1998 when the left internal thoracic artery had been anastomosed to the obtuse marginal at another hospital. CTCA was performed with a 64-slice CT scanner (Aquilion 64, Toshiba). Scans obtained in the sub-MIP view showed a large calcified plaque at the entrance to a total occlusion of the RCA (Figure 1). The length of the CTO was about 20 mm. A stent implanted at the RCA ostium 10 years previously was also well visualized. It seemed to be misdirected toward a side branch, and the proximal part of the stent was seen to be located in a false lumen on short axis views of the RCA (Figure 2).

On examination, the patient was conscious; blood pressure was 136/80 mm Hg; pulse rate was 60/min (regular); heart and breath sounds were normal; and there were no abnormalities of the abdomen or limbs. Full blood count and electrolytes were normal. The electrocardiogram showed sinus rhythm.

On coronary angiography (Figure 3), the RCA was totally occluded at its ostium. Selective catheterization of the left coronary artery showed retrograde filling of the RCA through a large collateral vessel (Rentrop grade III) arising from a septal branch of the left anterior descending coronary artery (LAD). Left ventriculography showed normal wall motion.

PCI procedure. Based on the above findings, the patient was scheduled to undergo percutaneous recanalization of the RCA. It was predicted that the guidewire would not enter the true lumen via the antegrade approach due to the position of the old stent based on CTCA findings. Therefore, we attempted the retrograde approach via a septal collateral vessel.

First, 7 Fr sheaths were inserted into the bilateral femoral arteries, and a 7 Fr AL 1.0 Launcher guide catheter (Medtronic Inc.) was advanced from the right femoral artery into the RCA, while a 7 Fr 90 cm EBU 3.50 Launcher guide catheter (Medtronic) was advanced from the left femoral artery into the left coronary artery (LCA). A Runthrough hypercoat guidewire (Terumo Corp.) with the support of a Finecross microcatheter (Terumo) crossed the septal branch from the LAD, allowing access to the RCA. Then the guidewire was changed to a Fielder FC (Asahi Intecc Co. Ltd.) and advanced into the distal segment of the CTO (Figure 4). We attempted the antegrade approach by the kissing wire technique with an antegrade Conquest Pro guidewire and a retrograde Miracle 6 g guidewire (Asahi). However, both guidewires deviated into the subintimal space and could not cross the CTO because of obstruction by the stent. Therefore, we tried the controlled antegrade and retrograde subintimal tracking (CART) technique. A Fielder FC guidewire was advanced retrogradely into the subintimal space and a 1.25 x 10 mm Ryujin Plus OTW balloon (Terumo) was passed through the stent struts (Figure 5). The lesion was dilated with a Sprinter Legend 2.0 x 10 mm balloon (Medtronic), and the antegrade Conquest Pro guidewire (Asahi) successfully crossed the CTO to enter the true lumen (Figure 6). This guidewire was subsequently exchanged for a Runthrough hypercoat guidewire (Terumo) (Figure 7). Intravascular ultrasound confirmed that the wire had crossed the occlusion through the subintimal space by running along the outer border of the stent and had re-entered the distal true lumen as expected. Two Cypher stents (Cordis Corp.) were placed and expanded to 20 atm, including a 2.5 x 23 mm distal stent and a 3.0 x 33 mm proximal stent. The final angiogram revealed an excellent result (Figure 8). After the procedure, the patient was stable without elevation of enzymes. The 8-month follow-up angiogram showed no restenosis.

Discussion. PCI for the treatment of CTO has recently shown marked advances and the initial outcome has improved dramatically.^2,3 The retrograde approach involves advancing a guidewire to cross the CTO from the distal side via a collateral vessel, and it has become more popular recently.^5,6

Di Mario et al reported that the success rate of PCI for CTO was 76.5% in 17 patients treated by the retrograde approach up to 2007.¹⁰ Rathore et al achieved a guidewire success rate of 75.2% and a procedural success rate of 65.6% with the retrograde approach in 157 patients,¹¹ while Saito et al reported a guidewire success rate of 82% and a procedural success rate of 84% in 45 patients.⁹

Problems that arise with the retrograde approach include difficulty in advancing the guidewire through the collateral channel, as well as subsequently crossing the CTO with the guidewire and devices. In the patient reported here, the stent previously implanted at the RCA ostium was angled toward a side branch on pre-procedural CTCA. Although the stent proximal to the mid segment of the CTO seemed to be inside the true lumen on the normal MIP view, the mid-to-distal part of the stent was found to be in a false lumen on the short axis view. Thus, the information obtained by pre-procedural CTCA was useful for deciding the therapeutic strategy. We predicted that a guidewire would not be able to enter the true lumen via the antegrade approach based on the CTCA findings, so we employed the retrograde approach via a septal collateral. Because the stent was implanted in a false lumen, we performed balloon dilatation of the subintimal space and stent struts and succeeded in advancing the guidewire by the CART technique after failure of the kissing wire technique and knuckle wire technique.

The CART technique is one of the most important skills for the retrograde approach. A subintimal dissection is created retrogradely, which allows the operator to limit extension of the dissection to the CTO portion.

Usually, a retrograde guidewire that has entered the occluded vessel is used to cross the CTO. When this fails, the guidewire is replaced with a slightly firmer guidewire such as one from the Miracle series (Asahi), and retrograde crossing of the CTO is tried again, or the kissing wire technique is attempted with an antegrade guidewire being simultaneously employed. When the retrograde guidewire and a microcatheter can be inserted into the contralateral guide catheter, the procedure can be performed successfully by the “retrograde wire-crossing technique” in which the initial guidewire is replaced with a 3 mm guidewire and pulled out through the contralateral sheath.¹²

When the retrograde guidewire enters a false lumen and penetrating the CTO is difficult, the CART⁸ and reverse CART⁹ techniques are widely used. Surmely et al⁸ reported 10 patients with CTO who were successfully treated by the CART technique. In this technique, a balloon is inserted retrogradely along a retrograde guidewire that lies in a false lumen and is inflated to expand the false lumen, after which an antegrade guidewire is advanced into the true lumen distal to the CTO via the expanded false lumen. Recently, the reverse CART technique has been reported, during which a balloon is inserted via the antegrade approach to expand the false lumen. After that, a retrograde guidewire is advanced.⁹ This technique is simple, but there is a risk of causing severe dissection.

Until now, PCI for CTO had been limited to lesions without features that are known to be predictors of a poor outcome, such as a length >15 mm and calcification of the occluded vessel.¹⁶ CTCA allows reliable evaluation of coronary plaque morphology¹⁷ and has several advantages for assessment of CTO compared with conventional angiography. It does not require selective catheterization to visualize the vessel lumen and calcification is easily detected. Also, the 3-dimensional information provided allows accurate measurement of length that does not suffer from calibration problems, foreshortening, or failure of collateral filling as occurs with conventional angiography. Mollet et al¹⁵ performed CTCA for CTO in 45 patients and multivariate analysis identified a blunt stump on conventional angiography, CTO length >15 mm, and severe calcification on CTCA as independent predictors of procedural failure.

IVUS-guided PCI for CTO has also been reported. Rathore et al¹⁸ reported that the IVUS-guided reverse CART technique was successful in 30/31 cases (96.8%). IVUS seems to be useful to find the entry point and the true lumen of the CTO in real-time. However, overall characteristics of a CTO, such as lesion length and the site of calcification, cannot be assessed. In contrast, CTCA not only provides information about lesion characteristics, but also gives anatomical information about a CTO. CTCA combines noninvasive imaging with invasive functional information, making it a useful imaging modality for planning the treatment of CTO. This may be the first case in which PCI for CTO was planned from CTCA findings. Information provided by CTCA could increase the primary success rate of PCI in patients with CTO. In the present case, we successfully treated a very difficult CTO based on the results of pre-procedural CTCA.

CTCA may be better at predicting the outcome of PCI (success or failure) for CTO than traditional coronary angiography. Given the rapid improvement of CT technology, CTCA may play a larger role in intervention for CTO in the future.

Conclusion. We reported a successful case of retrograde PCI for CTO of the RCA in which the CART technique was employed to overcome problems related to a previously implanted stent that could be visualized by CTCA.

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From the Division of Cardiology, Saiseikai Yokohama City Eastern Hospital, Kanagawaken, Japan.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.
Manuscript submitted May 27, 2011, provisional acceptance given June 27, 2011, final version accepted August 3, 2011.
Address for correspondence: Hideyuki Takimura MD, 3-6-1 Shimosueyoshi, Tsurumiku, Yokohamashi, Kanagawaken, Japan 230-0012. Email: h_takimura@tobu.saiseikai.or.jp