Treating chronic total occlusions (CTOs) remains one of the major challenges in interventional cardiology. In the last 20 years, as the procedural outcomes of intervention for CTOs have significantly increased as a function of improved guidewires and devices, as well as operator technique and experience, successful recanalization of CTOs may now be achieved in approximately 80% of lesions. Various new techniques to cross CTOs have been introduced over the years, including the use of dedicated CTO wires, blunt dissection and other technologies.1,2
One of the new techniques for CTO treatment is the retrograde approach, whereby the occlusion site is approached in a retrograde fashion through a large collateral channel from any other patent coronary artery.3,4 Most interventions for CTO using a retrograde approach are achieved transfemorally, however, local complications associated with femoral artery access may pose serious clinical complications. The transradial approach reduces vascular and bleeding complications at the puncture site, improves patient comfort and decreases the length of hospitalization compared with the femoral approach.5,6 Also, in cases with severe peripheral artery disease and abdominal aortic aneurysm, the transfemoral approach is not suitable. We report 4 CTO cases successfully treated with a retrograde approach using access via biradial arteries.
Case 1. A 52-year-old male was referred for coronary angiography because of recurrent chest pain upon exertion. His coronary angiogram showed a CTO proximal to the left anterior descending artery (LAD) with collaterals from the right coronary artery (RCA) via a septal branch (Figures 1A and B). He preferred to undergo coronary angioplasty with the transradial approach because of the shorter hospitalization period and lower cost. Thus we performed his coronary angioplasty using the radial approach on December 15, 2006.
Following an unsuccessful traditional antegrade approach of the CTO lesion, we attempted a retrograde approach by using the right and left radial arteries. A 7 Fr JR 3.5SH Launcher guide catheter (Medtronic Inc., Minneapolis, Minnesota) was inserted from the right radial artery into the RCA, and a 6 Fr EBU 3.75 Launcher guide catheter was inserted from left radial artery into the left coronary artery (LCA). Because we usually use the right radial artery for PCI, we chose his right radial artery for the collateralizing vessel. A Runthrough Hypercoat guidewire (Guidant Corp., Indianapolis, Indiana) with support of the Finecross microcatheter (Terumo Corp., Tokyo, Japan) from the RCA was passed distal to the right posterior descending artery to the collateral route of the septal branch, allowing access to the LAD. For the retrograde approach, we usually use a hydrophilic floppy wire to pass small (zig-zag) collateral vessels.4 With careful manipulation, the guidewire passed through the occluded lesion from the retrograde direction (Figure 1C). After confirming that the guidewire was in the true lumen, we attempted the antegrade approach again with a Miracle Primo guidewire (Asahi Intecc Co. Ltd., Aichi, Japan) and a Ryujin Plus 1.25–10 mm balloon (Terumo) with the help of a retrograde guidewire as a marker, and successfully crossed the CTO lesion (Figure 1D). The lesion was dilated with the balloon and the Ryujin Plus 3.0–15 mm balloon (Figure 1E). Two Cypher stents (Cordis Corp., Miami, Florida) were placed using 20 atm of pressure (2.5–28 mm at the mid-LAD and 3.5–18 mm at the proximal CTO lesion). After crossing a guidewire to the first diagonal branch, post-stent kissing-balloon dilatation was performed (Figure 1F).
Case 2. A 77-year-old female with a history of stent implantation in the distal RCA presented with chest pain experienced during rehabilitation exercise. She underwent operation of a lumbar spinal canal stenosis 3 months prior. Her angiogram showed a CTO in the proximal RCA with collaterals from the septal branch of the LAD to the distal RCA (Figure 2B). Her PCI was planned as a biradial retrograde approach on December 16, 2006 because she could not tolerate prolonged bed rest in the supine position.
A 7 Fr Launcher EBU 3.5 guide catheter was inserted from the right radial artery into the LCA, and a 7 Fr JR3.5 Launcher guide catheter was inserted from the left radial artery into the RCA (Figure 2A). A Fielder guidewire with support of the Finecross microcatheter was passed through the LAD and septal branch and reached the distal aspect of the occluded RCA lesion (Figure 2C). Because a Fielder guidewire (Asahi) did not cross the CTO, a Miracle 3 guidewire and Ryujin Plus 1.25–15 mm over-the-wire balloon wasused. The guidewire was passed into the CTO lesion and reached the guide catheter of the RCA. After confirmation that the guidewire was in the true lumen, the CTO lesion was dilated using the Ryujin Plus 2.0–15 mm balloon from the retrograde route. Next, the antegrade approach was easily performed using a Runthrough Hypercoat guidewire (Figure 2D). Finally, 3 Cypher stents were implanted in the RCA (Figures 2E and 2F).
The other 2 patients underwent PCI for CTO via a retrograde approach using the biradial arteries because they had severe peripheral artery disease and abdominal aortic aneurysms.
Discussion. Recent data have shown that successful percutaneous recanalization of coronary CTOs results in improved survival as well as enhanced left ventricular function, reduced angina and improved exercise tolerance.7–10 Although several studies showed favorable results with bare-metal stent implantation in CTO lesions, there are still significantly higher rates of restenosis (32–55%) and reocclusion (8–12%) after bare-metal stent implantation. Recent studies have shown more favorable results using drug-eluting stents for CTO lesions compared to bare-metal stents.11 As a result, tremendous interest has recently emerged among interventional cardiologists to learn the principles and develop the advanced skills required to maximize procedural outcomes in CTO treatment.
Approximately 10 years ago, the success of CTO recanalization with conventional guidewires was about 50–60%. Recently,(Lumend Inc., Redwood City, California) and the Flowcardia Crosser System (Flowcardia Inc., Sunnyvale, California). New strategies include subintimal tracking and reentry with the side branch technique, the parallel wire technique, the intravascular ultrasoundguided technique and the retrograde approach.4
Although the retrograde approach for the percutaneous treatment of nonocclusive coronary artery disease is an old concept introduced in the late 1980s,13 its application in the treatment of CTOs was first performed in the early 1990s and has been regularly presented at interventional conferences and live demonstrations since 1998. In patients with a CTO who have well-developed collaterals, switching to a retrograde approach is an option, especially when there is difficulty in crossing the lesion with an antegrade wire.
In CTOs, collaterals may develop from a septal branch, right ventricular branch, conus branch from the RCA in an LAD case, and from the LAD in a RCA case. If PCI access is attempted in collaterals that run along the surface of the heart, wire-crossing to the lesion is difficult due to vessel tortuosity, and the risk of cardiac tamponade due to perforation or rupture of the arteries is high. As septal branches run through the cardiac septal wall, the risk of cardiac tamponade and perforation are relatively low. In our 4 patients, we chose the septal branch as the route for the retrograde approach without the occurrence of vessel dissection or perforation.
Femoral artery access is preferred for CTO angioplasty by most operators, with utilization of 7–8 Fr guides for passive support, necessitating excellent guiding catheter support. A 6 Fr catheter may be considered for short occlusions or by operators skilled with active guide manipulation. Also, most cases of retrograde approach are performed via femoral artery access. But there is no reason that the retrograde approach cannot be performed using radial artery access. A large sheath (7 Fr or even 8 Fr) may be used in the radial approach in some cases.14 Here, we showed feasibility of the retrograde approach by using biradial arteries in CTO treatment.
In our cases, there were several reasons why PCI was not performed femorally. One patient had lumbar spinal canal stenosis which precluded her from staying in a supine position. Another patient preferred the transradial approach because of the shorter hospitalization period and lower cost. The other 2 patients had peripheral artery disease and abdominal aortic aneurysms.
In all of our cases, traditional antegrade PCI was difficult, but retrograde penetration of the wire was relatively easy. The distal fibrous cap of the CTO may be weaker than the proximal fibrous cap, resulting in easier wire crossing. In such cases, the retrograde approach is reasonable via transradial access because of its relatively weak backup support of the guide catheter.
The occurrence of local complications during PCI performed via the femoral artery is a serious clinical problem, especially in elderly patients or when using antiplatelet agents. The transradial approach for PCI reduces vascular and bleeding complications at the puncture site, improves patient comfort and decreases the length of hospitalization compared with the femoral approach.5,6 In a meta-analysis of trials comparing femoral and radial approaches, radial access was associated with a significantly lower rate of entry-site complications.6 In CTO cases, PCI requires a longer procedure time than PCI of non-occluded vessels. A long procedure time increases the heparin dose needed and increases bleeding complications. In the femoral approach, back pain may be increased due to prolonged supine positioning in addition to increased bleeding complications with the use of larger sheaths. In our 4 cases, patients were able to move freely within 1 hour after the procedure, and none of the patients experienced bleeding complications.
In recent years, transradial intervention (TRI) has increased in popularity and has been adapted to various conditions including CTOs. TRI has the possibility of adapting to most new techniques and situations.
In conclusion, to the best of our knowledge, we report the first cases in the literature of successful coronary intervention via a retrograde approach in CTO lesions by using right and left radial approaches. In selected cases, the retrograde approach via the biradial arteries in the treatment of CTOs appears feasible.
Acknowledgment. The authors wish to thank Heidi N. Bonneau, RN, MS, for her expert review of the manuscript.
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