ADVERTISEMENT
Case Report
Transradial Treatment of Bifurcation Coronary Disease Using the
Multi-Link Frontier‚Ñ¢ Bifurcation Stent System
October 2005
The percutaneous revascularization of coronary bifurcation lesions by coronary stenting remains technically challenging. Side branch occlusion due to plaque shift can occur during stenting of the main branch, and this may result in non-Q wave myocardial infarction.1 Long-term results are limited by the increased rates of restenosis compared to non-bifurcation lesions.2 Numerous techniques have been described in an attempt to preserve side branch patency.3 However, adequate treatment of the side branch ostium remains problematic.
The first generation of bifurcation stents were standard tubular stents with a side aperture that allowed guidewire access to the side branch while stenting the main branch.4 Poor delivery of these stents to distal lesions, potential twisting of the guidewires around each other and the inability to stent the ostium of the side branch were major limitations.
The Multi-Link Frontier™ bifurcation stent (Guidant Corporation, Santa Clara, California) allows stenting of the main branch and the side branch ostium with a single stent. The device is compatible with a 7 French (Fr) guiding catheter. In this article, we present our experience with the Multi-Link Frontier stent using the transradial approach for the treatment of coronary bifurcation lesions.
Stent Design
The Multi-Link Frontier stent is a flexible stainless steel slotted tube stent with a central portal that allows side branch access. The crossing profile of the undeployed stent is 0.064 inches. The stent is designed so that the rings proximal to the portal have seven crests, nine crests at the portal and six crests each at the distal rings. The stent is mounted onto a delivery system that consists of two joined balloons. The tips of the two balloons are held together with a mandrel that allows the stent to be delivered as a single unit. Three radiopaque markers are located underneath the main branch balloon. The two outer markers show the proximal and distal margins of the stent. The central marker is located adjacent to the side branch portal (Figure 1).
Using a rapid exchange monorail channel, the stent is positioned just proximal to the bifurcation. The mandrel is removed, which releases the side branch balloon. The side branch is then crossed with an exchange length guidewire, which is passed down an over-the-wire channel of the delivery system. The unit is advanced and rotated until the central marker is adjacent to the side branch ostium. Using a single indeflator, the two delivery balloons can be inflated simultaneously. This results in the deployment of the Multi-Link Frontier stent in the main branch and the side branch ostium. The system can then be retracted, preserving access to both branches. On deployment, the proximal stent dimensions are greater than the distal segment. This feature allows for vessel tapering that often occurs after a large side branch.
The stent is manufactured with a length of 18 mm, and is available in four sizes (2.5, 3.0, 3.5 and 4.0 mm). This corresponds to the diameter of the distal stent when deployed at nominal pressure (8 atm).
Selection of Cases for Treatment with the Multi-Link Frontier Stent
Only one out of the five interventional cardiologists in our institution is trained to use the Multi-Link Frontier stent. The Multi-Link Frontier stent was used in the treatment of bifurcation lesions where there was significant threat to a large side branch (2.0 mm diameter) without severe proximal vessel tortuosity or calcification. Angiographic appearances of high-risk lesions included cases with severe disease involving the ostium of the side branch or bulky plaque disease in the main vessel adjacent to the side branch. Cases in which the angle of the side branch was perpendicular to the main branch and the ostium of the side branch was free of significant disease were often treated with conventional stent placement in the main vessel. Over a four-month period (May 13–September 14, 2004), 36/142 (25%) of the PCI lesions performed by this operator (JLM) were classified as bifurcation lesions. The Multi-Link Frontier stent was used in 8/36 (22%) of thesebifurcation lesions. The first three cases were performed via the femoral route. The next five cases were performed using the transradial approach, and are presented in this paper. Reasons for not using the Multi-Link Frontier stent include low risk of compromise to the side branch in 14/36 (39%), small side branch in 3/36 (8%) and excessive tortuosity at or proximal to the lesion in 7/36 (19%) of cases. In 3/36 (8%) of cases, the bifurcation lesion was only visible after recanalization of a proximal occlusion in the main vessel. These cases were treated with conventional stents. In one case, the bifurcation lesion was due to in-stent restenosis which was treated with drug-eluting stents.
There were no cases where the Multi-Link Frontier stent could not be deployed at the lesion site. No access or postprocedure vascular problems were encountered using the transradial approach.
Patient Characteristics
Five male patients with a mean age of 56.4 years were treated with the Multi-Link Frontier stent using the transradial approach. All procedures were performed on a routine basis, with patients having stable angina pectoris associated with positive exercise tolerance tests. Two patients had previous myocardial infarction. The lesion sites were the left anterior descending artery/diagonal branch in four patients and posterolateral branch/posterior descending artery in one patient.
Procedural Details
All patients were pre-treated with 600 mg of clopidogrel and 600 mg of aspirin. Arterial access was gained via the right radial artery using a 7 Fr radial sheath (Cook Group Inc., Bloomington, Indiana). All patients had a satisfactory Allen’s test, indicating adequate collateral supply from the ulnar artery. Guiding catheters used for the left coronary artery were the 7 Fr Judkins Left 3.5 or 4.0 (Cordis Corporation, Miami Lakes, Florida), and for the right coronary artery, the 7 Fr Judkins Right 4 (Cordis Corporation). Intravenous heparin was administered to achieve an activated clotting time of > 250 seconds and abciximab was given at the start of the procedure in all cases. Balanced MiddleWeight (Guidant Corp.) guidewires were used to cross the side branch and the main vessel in all cases. The stiffer body of these wires may assist in the rotation of the stent which is required to align the side branch portal with the ostium of the side branch. Predilatation of the main vessel was performed in all patients, and of the side branch in two patients. Successful device delivery and stenting of the bifurcation lesion with preservation of the side branch was achieved in all five cases. In three cases, additional stenting of the side branch was required to cover residual stenoses in two cases, and dissection in one. In cases where the side branch was stented, a final“kissing balloon” postdilatation in both branches was performed.
In the cases involving the left anterior descending artery/diagonal bifurcation, 3.0 x 15 mm Multi-Link Frontier stents were deployed at 12 atm. In the case involving the posterolateral branch/posterior descending artery bifurcation, a 2.5 x 15 mm Multi-Link Frontier stent was deployed at 12 atm. In this patient, the first Multi-Link Frontier stent was displaced from the delivery balloon when attempting to retrieve the stent into the guide catheter after failure to cross the lesion. This stent was deployed in an area of stenosis in the mid-right coronary artery and after further predilatation, a second Multi-Link Frontier stent was successfully deployed at the distal bifurcation. An example of this device being used for a left anterior descending artery/diagonal bifurcation is shown in Figure 2.
Angiographic success defined as 5,6 Saito et al. showed that the incidence of severe flow reduction in the radial artery after transradial intervention was no different between cases involving 6 Fr and 7 Fr guide catheters.7 The cases we describe show that the Multi-Link Frontier stent can be used safely through the transradial approach, allowing the benefits of this approach8 to be combined with a device specifically designed for bifurcation lesions.
Long-term clinical and angiographic follow-up for the Multi-Link Frontier stent has been presented.9 In 150 patients treated with a Multi-Link Frontier stent, the 6-month target vessel revascularization rate was 22.9%. In 95 patients where angiographic follow-up was performed, the binary restenosis rates in the main branch were 25.3% and 29.1% in the side branch. Restenosis rates were lower in the side branch when balloon angioplasty was performed compared to stenting or no treatment (19.4%, 35.9% and 31.3%, respectively).
Several techniques for the treatment of bifurcation lesions with coronary stents have been described. This has included stenting of the main branch with angioplasty of the side branch or stenting of both branches. The need for subsequent target vessel revascularization using bare metal stents has ranged from 17–53%.10–12 Restenosis at the ostium of the side branch is a common problem, and stenting of the side branch is associated with higher restenosis rates compared to balloon angioplasty alone.13
In studies using sirolimus-eluting stents in both branches for bifurcation coronary lesions, restenosis in the side branch remains a problem.14,15 Failure to cover the ostium of the side branch with drug-eluting stents using T- or Y-stenting may explain the high restensosis rates observed on follow-up. Crush stenting has been advocated in an attempt to ensure adequate coverage of the bifurcation ostium.16 However, this technique is associated with several layers of stent struts in the proximal main branch and the long-term results are not known.
The Multi-Link Frontier stent enables coverage of the side branch ostium that is difficult to achieve with conventional stent design. Future developments combining drug-eluting technology with specifically designed bifurcation stents will improve the results of bifurcation stenting. The feasibility of using the transradial approach for performing complex bifurcation stenting will optimize patient comfort while minimizing bleeding complications.
1. Aliabadi D, Tilli FV, Bowers TR, et al. Incidence and angiographic predictors of side branch occlusion following high-pressure intracoronary stenting. Am J Cardiol 1997;80:994–997.
2. Sheiban I, Albiero R, Marsico F, et al. Immediate and long-term results of “T” stenting for bifurcation coronary lesions. Am J Cardiol 2000;85:1141–1144.
3. Louvard Y, Lefevre T, Morice MC. Percutaneous coronary intervention for bifurcation coronary disease. Heart 2004;90:713–722.
4. Toutouzas K, Stankovic G, Takagi T, et al. A new dedicated stent and delivery system for the treatment of bifurcation lesions: Preliminary experience. Catheter Cardiovasc Interv 2003;58:34-42.
5. Chen YH, Wu CJ, Chang HW, et al. Effects and safety of intracoronary thrombectomy using transradial application of the PercuSurge distal balloon protection system in patients with early or recent myocardial infarction. Cardiology 2004;102:206–214.
6. Wu SS, Galani RJ, Bahro A, et al. Eight French transradial coronary interventions: Clinical outcome and late effects on the radial artery and hand function. J Invasive Cardiol 2000;12:605–609.
7. Saito S, Ikei H, Hosokawa G, Tanaka S. Influence of the ratio between radial artery inner diameter and sheath outer diameter on radial artery flow after transradial intervention. Catheter Cardiovasc Interv 1999;46:173–178.
8. Agostoni P, Biondi-Zoccai GG, de Benedictis ML, et al. Radial versus femoral approach for percutaneous coronary diagnostic and interventional procedures. Systematic overview and meta-analysis of randomized trials. J Am Coll Cardiol 2004;44:349–356.
9. Transcatheter Therapeutic Meeting, Washington. September 16th 2003. http://www.tctmd.com/expert-presentations/multi-slide.html?product_id=6536.
10. Al Suwaidi J, Berger PB, Rihal CS, et al. Immediate and long-term outcome of intracoronary stent implantation for true bifurcation lesions. J Am Coll Cardiol 2000;35:929–936.
11. Anzuini A, Briguori C, Rosanio S, et al. Immediate and long-term clinical and angiographic results from Wiktor stent treatment for true bifurcation narrowings. Am J Cardiol 2001;88:1246–1250.
12. Yamashita T, Nishida T, Adamian MG, et al. Bifurcation lesions: Two stents versus one stent–immediate and follow-up results. J Am Coll Cardiol 2000; 35:1145–1151.
13. Assali AR, Teplitsky I, Hasdai D, et al. Coronary bifurcation lesions: To stent one branch or both? J Invasive Cardiol 2004;16:447–450.
14. Colombo A, Moses JW, Morice MC, et al. Randomized study to evaluate sirolimus-eluting stents implanted at coronary bifurcation lesions. Circulation 2004;109:1244–1249.
15. Tanabe K, Hoye A, Lemos PA, et al. Restenosis rates following bifurcation stenting with sirolimus-eluting stents for de novo narrowings. Am J Cardiol 2004;94:115–118.
16. Colombo A, Stankovic G, Orlic D, et al. The modified “T” stenting technique with “crushing” for bifurcation lesions: Immediate results and 30-day outcome. Catheter Cardiovasc Interv 2003;60:145–151.
