The Utility of Extension Catheters in Transradial Percutaneous Coronary Intervention

Abstract: Objectives. To evaluate the use of extension catheters in transradial intervention of complex coronary lesions. Background. Complex percutaneous coronary intervention (PCI) via transradial approach remains a challenge for many interventionalists, primarily due to the difficulty in obtaining adequate guide catheter support. Methods. A retrospective case series identified 54 patients who presented for PCI of complex coronary lesions. A lesion was defined as complex if it contained severe calcification, proximal tortuosity, chronic total occlusion, or was located distal to a previously implanted stent. After identifying the complex lesions, a conversion to femoral approach was considered, but an attempt via the transradial approach with the use of an extension catheter was chosen as the initial strategy. Specific cases highlighting this approach are illustrated in detail. Results. The average age of the patients was 72 years old, with male predominance (55%). The success rate of completing the transradial intervention with the help of an extension catheter was 96%. Stent delivery failed due to severe tortuosity and calcification in only 2 cases. The coronary artery involved was either the left anterior descending (n = 25), the left circumflex (n = 10), the right coronary artery (n = 14), or a saphenous vein graft (n = 5). There were no coronary dissections evident from use of the extension catheter. Conclusion. In the treatment of complex coronary lesions via the transradial approach, the use of an extension catheter may assist in improving successful intervention and decrease the frequency of crossover to a femoral approach.

J INVASIVE CARDIOL 2015;27(1):28-32
Key words: access approach, complex PCI, transradial intervention

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Percutaneous coronary intervention (PCI) performed via the transradial approach is gaining momentum worldwide as a result of fewer access-site complications and better clinical outcomes in certain patient subsets.¹ However, there is still the perception that transradial intervention (TRI) can only be performed in simple lesions due to the lack of necessary back-up support from the guide catheter. Currently, in lesions containing severe calcification, proximal tortuosity, chronic total occlusion (CTO), or lesions located distal to a previously implanted stent, the traditional femoral approach is considered the first-line strategy by many. Lack of guide-catheter support is one of the main risk factors for TRI failure and requires conversion to the femoral approach in about 7% of cases in a recent analysis.² As a result, different techniques have been developed to help combat this apparent downside to TRI, such as the buddy-wire technique,³ the balloon-anchor technique,⁴ the 5-in-6 (“mother-daughter”) catheter technique,^5,6 or simply upsizing to a larger guide catheter. The 5-in-6 catheter technique, which inserts a longer 5 Fr guide catheter into a 6 Fr guide catheter, has been used for many years to increase back-up support.^5,6 Applying a similar concept, several rapid-exchange extension catheter systems have been approved in the United States and have been widely used in recent years as well.⁷ In this article, we summarize our experience using this extension catheter for TRI of complex lesions. We believe that the extension catheter is an essential tool for successful TRI in this lesion subset.

Methods

Between July 2013 and November 2013, a retrospective analysis of 220 patients undergoing PCI via the transradial approach was performed. Fifty-four cases were then identified as complex coronary lesions, defined by severe calcification, proximal tortuosity, CTO, or location distal to a previously implanted stent. After identifying the complex lesions, a conversion to femoral approach was considered, but an attempt via the transradial approach with the use of an extension catheter was chosen as the initial strategy. Patient and procedural characteristics of this subset were obtained through medical chart review. Informed written consent was obtained from each patient. The extension catheters used in this study were the GuideLiner V2 (Vascular Solutions) or Guidezilla (Boston Scientific Corporation). Extra-support large 6 Fr guide catheters were used in all cases, including the Launcher EBU 3.5 (Medtronic, Inc), Launcher EBU 3.75, Launcher AL 0.75, Launcher AL 1.0, Launcher SAL 0.75, and Launcher SAL 1.0. Procedural success was defined as <20% residual stenosis after stent implantation and TIMI-3 distal blood flow of the treated vessel at the end of the procedure.

Results

Table 1 shows the baseline patient characteristics of the extension catheter group. The average age of the patients was 72 years, with male predominance (55%). Table 2 shows the procedural characteristics. The success rate of TRI with the help of an extension catheter was 96%. Rotational atherectomy was performed in cases with severe calcification prior to utilization of an extension catheter (15 cases). The stents were unable to be delivered due to severe tortuosity and calcification in only 2 patients. Rotational atherectomy was also considered, but deemed unsafe in these 2 cases. In the successful cases, once the extension catheter was utilized, balloons and stents were able to cross the lesion and PCI was performed as planned. No patient suffered a coronary dissection. Specific case examples using the extension catheter are illustrated in detail below. These cases highlight common scenarios that other interventionalists may encounter.

Case 1

Deep intubation of the extension catheter in a calcified distal right coronary artery bifurcation lesion with proximal tortuosity. A 60-year-old woman with a history of hypertension presented with unstable angina and was referred for PCI of the distal RCA (Figure 1A). The lesion was attempted twice at an outside institution without success. A 6 Fr Slender Glidesheath (Terumo Corporation) was inserted into the right radial artery. A 6 Fr Launcher SAL 0.75 guide catheter was used to engage the RCA. Due to the severe distal calcified lesion, we utilized the extension catheter, deeply intubated the artery, and advanced the extension catheter into the distal vessel by using the coaxial balloon-anchor technique. The technique consists of inflating a balloon at the lesion and then advancing the extension catheter down to the distal vessel (Figure 1B). The stent was then delivered to the lesion without further difficulty (Figure 1C).

Of note, this extension catheter has an inner diameter equivalent to a 5 Fr guide catheter. It is able to accommodate one stent catheter and one 0.014˝ guidewire together (Figure 1B). For the simple approach, the jailed guidewire technique is sufficient to keep the side branch open. However, there will not be sufficient room for regular kissing balloons,  two stents, or an atherectomy device.

Case 2

Delivering stents in a severely tortuous right coronary artery lesion. A 58-year-old man with a history of hypertension presented with crescendo angina and was referred for PCI of a mid-RCA lesion (Figure 2A). A 6 Fr Slender Glidesheath was inserted into the right radial artery. A Launcher SAL 0.75 guiding catheter was used. Using microcatheter support, a Pilot 200 guidewire (Abbott Laboratories) successfully crossed the lesion. A small, 1.20 x 12 mm Emerge balloon (Boston Scientific) was used to predilate the lesion. However, no other balloons were able to navigate through the tortuosity of the artery. Subsequently, we used the coaxial balloon-anchor technique to deeply intubate the extension catheter (Figure 2B). Figure 2C showed the final result after 3 stents were placed.

Case 3

Delivering a stent to a calcified left circumflex artery lesion distal to a previously implanted stent in the left main artery. A 67-year-old man presented with crescendo angina refractory to medical therapy and was referred for PCI of a mid-LCX lesion. He had a previous history of coronary artery bypass graft (CABG) surgery with a known occlusion of a saphenous venous graft (SVG) to the obtuse marginal branch (OM). A stent from LM to LCX was implanted several years ago (Figure 3A). A 6 Fr Slender Glidesheath was inserted into the right radial artery. A 6 Fr Launcher EBU 3.5 guiding catheter was used to engage LM artery. Several factors made this lesion challenging via transradial approach, including an acute angle of LM-LCX, previous stents, and severe calcification. An extension catheter was inserted and deeply intubated distal to the LM artery (Figure 3B). The stent was easily delivered with the aid of the deeply intubated extension catheter (Figure 3C).

Case 4

Delivering a stent to a saphenous vein graft lesion. A 70-year-old man with a history of CABG 10 years prior was referred for PCI of a SVG to RCA for unstable angina. SVG intervention from the transradial approach is challenging due the difficulty in obtaining adequate back-up support.⁸ A 6 Fr Slender Glidesheath was inserted into the right radial artery. A 6 Fr Launcher AL 1.0 guide catheter was used to engage the SVG to RCA. A 5.0 mm Spider FX embolic protection device (ev3, Inc) was positioned distally (Figure 4). Due to severe calcification, the stent was unable to be delivered on the first attempt. However, with the assistance of the extension catheter, the stent was delivered to the lesion without much difficulty.

Case 5

Chronic total occlusion intervention with the CrossBoss catheter and an extension catheter via transradial approach. A 58-year-old male patient with a known total occlusion of the LAD was referred for PCI for the treatment of crescendo angina refractory to optimal medical therapy. The transradial approach was used via right radial artery and a 6 Fr Launcher EBU 3.5 guide catheter was chosen to engage the LM. A Pilot 200 guidewire was loaded inside of a CrossBoss catheter (Boston Scientific Corporation). Using an extension catheter to provide adequate back-up support, the CrossBoss catheter was able to cross the CTO lesion and spin into the true lumen (Figure 5). Stenting was completed at the end of the procedure without complication.

Discussion

The transradial approach is becoming common practice in the percutaneous treatment of coronary artery disease. The number of TRI cases has steadily increased in recent years, not only due to its safety and patient preference, but also because of significant improvements in operator skill and comfort with the approach. However, TRI is still a challenge in the treatment of complex coronary lesions due to the lack of adequate guide catheter support.² Many experienced interventionalists have employed various techniques to combat the problem of guide catheter support, but conversion to the femoral route is still unavoidable in certain cases. In this case series, we describe our experience in treating complex coronary lesions via the transradial approach using an extension catheter. We believe this approach may make TRI more feasible in this lesion subset and preclude the need for conversion to femoral access.

The 5-in-6 (“mother-daughter”) catheter technique is a remarkable development in PCI. The back-up support of a guide catheter has been shown to increase more than two-fold when using a 5-in-6 catheter system.⁹ Using this same concept, many extension catheters (eg, the Guideliner V2 [inner diameter, 0.056˝] and Guidezilla [inner diameter, 0.057˝]) were developed and are gaining popularity in the United States.^10-12 The 5 Fr lumen with coaxial guide extension can fit into a 6 Fr guiding catheter. The flexibility, lack of primary curve, and hydrophilic coating in the extension catheters can make deep intubation into the coronary artery possible without vessel trauma. However, at times, the use of the extension catheter may not be as straightforward, especially in highly complex cases. In the present case series, we also had to use the coaxial balloon-anchor technique in the majority of cases (93%). This technique consists of inflating a distal balloon, anchoring the guide catheter, and then advancing the extension catheter into a deep seated position closer to the lesion. With this maneuver, balloon or stent delivery to the complex lesion can be successfully achieved. By understanding the risks involved and exercising caution, while also speeding up the delivery process, no patient in our cohort suffered any cardiac events from this maneuver.

Direct comparison of the 5-in-6 catheter technique with a conventional buddy-wire or balloon-anchoring approach during TRI for complex lesions was previously investigated.¹³ The use of the 5-in-6 catheter technique was found to be more effective as a bail-out strategy. In our study, we used the extension catheter in a variety of complex lesions with a high procedural success rate and without an increase in complications. In all cases, we considered PCI via the femoral approach, as transradial stent delivery was extremely difficult. However, given our success with a small cohort of patients, we believe that the use of the extension catheter can increase PCI success with TRI. Thus, when considering treatment of complex coronary lesions, the use of an extension catheter as the initial approach in TRI before any traditional approaches, such as buddy wires, anchoring balloons, larger guiding catheters, or even femoral conversion, should be considered. Finding the most efficient and effective technique in these patients will save contrast volume, decrease fluoroscopy time, decrease procedure time, and decrease the rate of conversion to femoral approach.

Even with the benefits discussed, there are still a few limitations to the widespread use of this device. Due to the small inner diameter of the extension catheter, only a single stent and guidewire can be accommodated together. Therefore, when intervening on bifurcation lesions, kissing balloon inflations cannot be performed. However, in these cases, using a provisional jailed-guidewire technique to keep the side branch patent is still a feasible approach. Other limitations include the risk of coronary dissection with deep intubation of the catheter¹⁴ and possible hemodynamic instability associated with partial occlusion of coronary perfusion. However, as seen in the present case series, the combination of experienced operators, rapid stent delivery, and close monitoring can still lead to successful outcomes. Finally, while earlier models of extension catheters with a proximal metal collar exhibited a problem with stent deformation, the newer designs have seemingly resolved this issue.¹⁵

Study limitations. The main limitations are the small sample size and the retrospective nature of the study. Large, prospective trials are necessary to validate the data and compare outcomes against traditional approaches. Also, the definition of a complex case may vary among interventionalists and many may attempt the procedure without the use of an extension catheter in these scenarios.

Conclusion

The use of the extension catheter during TRI of complex coronary lesions may facilitate successful PCI without conversion to a femoral approach. Therefore, the use of an extension catheter may be considered as an initial strategy in the treatment of complex intervention via the transradial approach.

References

1. Rao SV, Cohen MG, Kandzari DE, Bertrand OF, Gilchrist IC. The transradial approach to percutaneous coronary interventions: historical perspective, current concepts, and future directions. J Am Coll Cardiol. 2010;55(20):2187-2195.
2. Abdelaal E, Brousseau-Provencher C, Montminy S, et al; Interventional Cardiologists at Quebec Heart-Lung Institute. Risk score, causes, and clinical impact of failure of transradial approach for percutaneous coronary interventions. JACC Cardiovasc Interv. 2013;6(11):1129-1137.
3. Jafary FH. When one won’t do it, use two-double “buddy” wire to facilitate stent advancement across a highly calcified artery. Catheter Cardiovasc Interv. 2006;67(5):721-723.
4. Fujita S, Tamai H, Kyo E, et al. New technique for superior guiding catheter support during advancement of a balloon in coronary angioplasty: the anchor technique. Catheter Cardiovasc Interv. 2003;59(4):482-488.
5. Hirokami M, Saito S, Muto H. Anchoring technique to improve guiding catheter support in coronary angioplasty of chronic total occlusions. Catheter Cardiovasc Interv. 2006;67(3):366-371.
6. Mamas MA, Eichhofer J, Hendry C, et al. Use of the Heartrail II catheter as a distal stent delivery device; an extended case series. Eurointervention. 2009;5(2):265-271.
7. Kumar S, Gorog DA, Secco GG, Di Mario C, Kukreja N. The GuideLiner “child” catheter for percutaneous coronary intervention-early clinical experience. J Invasive Cardiol. 2010;22(10):495-498.
8. Rathore S, Roberts E, Hakeem AR, Pauriah M, Beaumont A, Morris JL. The feasibility of percutaneous transradial coronary intervention for saphenous vein graft lesions and comparison with transfemoral route. J Interv Cardiol. 2009;22(4):336-340.
9. Takeshita S, Takagi A, Saito S. Backup support of the mother-child technique: technical considerations for the size of the mother guiding catheter. Catheter Cardiovasc Interv. 2012;80(2):292-297.
10. Eddin MJ, Armstrong EJ, Javed U, Rogers JH. Transradial interventions with the GuideLiner catheter: role of proximal vessel angulation. Cardiovasc Revasc Med. 2013;14(5):275-279.
11. de Man FH, Tandjung K, Hartmann M, et al. Usefulness and safety of the GuideLiner catheter to enhance intubation and support of guide catheters: insights from the Twente GuideLiner registry. EuroIntervention. 2012;8(3):336-344.
12. Cola C, Miranda F, Vaquerizo B, Fantuzzi A, Bruguera J. The GuideLiner catheter for stent delivery in difficult cases: tips and tricks. J Interv Cardiol. 2011;24(5):450-461.
13. Zhang Q, Zhang RY, Kirtane AJ, et al. The utility of a 5-in-6 double catheter technique in treating complex coronary lesions via transradial approach: the DOCA-TRI study. Eurointervention. 2012;8(7):848-854.
14. Chang YC, Fang HY, Chen TH, Wu CJ. Left main coronary artery bidirectional dissection caused by ejection of GuideLiner catheter from the guiding catheter. Catheter Cardiovasc Interv. 2013;82(3):E215-E220.
15. Papayannis AC, Michael TT, Brilakis ES. Challenges associated with use of the GuideLiner catheter in percutaneous coronary interventions. J Invasive Cardiol. 2012;24(7):370-371.

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From the 1Beth Israel Medical Center, New York, New York; 2West Virginia University, Charleston, West Virginia; 3Brody School of Medicine at East Carolina University, Greenville, North Carolina; 4the Commonwealth Medical College, Pennsylvania; and 5Apex Heart Institute, Ahmedabad, India.

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 7, 2014, provisional acceptance given July 9, 2014, final version accepted July 16, 2014.

Address for correspondence: Tak W. Kwan, MD, Senior Associate Director of Cardiac Catheterization Laboratory and Interventional Cardiology, Beth Israel Medical Center, 139 Centre St, Rm 307, New York, NY 10013. Email: Kwancardio@aol.com