Katherine Lee Chuy, MD; Shammah O. Williams, MD; Vinoy S. Prasad, MD, FSCAI; Faisal Latif, MD, FSCAI 

Introduction

Guide catheter support is key to successful percutaneous coronary interventions (PCIs). With various shapes and sizes to choose from, understanding the factors that influence guide support is important to achieve a stable platform for performance of safe and efficient PCIs.  

In this Tip of the Month, we discuss the general principles underlying guide support and provide practical tips to maximize guide support during PCIs.  

General Principles 

Two key factors enhancing the backup force of a guide catheter are the angle formed between the guide segment abutting the contralateral aortic wall (maximum support at 90 degrees) and the amount of aortic wall area the secondary curve rests on.^1,2 These are influenced by the catheter’s inherent design and chosen access site. The catheter design dictates the degree of passive or active support provided during a PCI. Passive support is derived from the catheter stiffness, size, and shape that allows the secondary curve to rest firmly against the opposite aortocoronary sinus or aortic wall without much manipulation.^1,2 Passive support catheters like Voda, EBU, XB, and Amplatz typically have a long tip, necessitating careful engagement to avoid coronary dissection.³ Conversely, active support requires manipulation to achieve additional backup power, positioning the guide to sit well in the aortic root and/or advancing further for deep intubation. An example includes assuming the “power position” with the Ikari Left or Judkins Left catheter.^1,2 The choice of access site also determines the primary attachment site of the catheter, which in turn affects the generation of backup force. This involves the brachiocephalic artery for right transradial interventions and the aortic arch for transfemoral interventions.⁴  

Guide catheter choice should take into account aortic root size, coronary ostium location, lesion location, and the amount of tortuosity and calcification needed to traverse to reach the lesion.¹ 

Practical Tips 

1. A guide catheter with a supportive shape should be used, such as the Voda/EBU/XB catheters for the left coronary artery, Amplatz Left (AL) for the right coronary artery (RCA), or Ikari Left with the option of assuming the “power position” for either coronary artery.  
2. A larger diameter guide (i.e., Fr size) provides greater passive support.¹ 
3. Longer sheaths can enhance the stiffness of the guide.¹ Longer sheaths bypass arterial tortuosity commonly encountered in the brachiocephalic-subclavian and iliofemoral arteries, allowing easier guide manipulation and torque transmission.  
4. Advancing the guide for deep intubation can be performed temporarily to facilitate device delivery across a tight lesion. To deep-seat a guide catheter, advance over the shaft of a balloon or stent with slight counterclockwise (to point to the left anterior descending [LAD] artery) or clockwise (to point to the left circumflex [LCX] artery or RCA) rotation.⁵  
5. For guide catheters such as the Ikari Left or Judkins Left, assuming the “power position” can be performed by pushing the guide until the secondary curve sits in the aortic sinus. To perform this safely, there should be no ostial or proximal lesions, and the guide should be seen further advancing into the coronary artery coaxially and not prolapsing into the aortic root.^1,2  
6. “Buddy wiring” can be performed to stabilize the guide catheter by advancing a second coronary wire either parallel to the first or into a side branch. Parallel wiring straightens the target vessel and provides a rail for device delivery. Side-branch wiring acts an anchor for additional support for a PCI of tight lesions in the main branch; prevents very deep guide intubation beyond the left main coronary while pulling out interventional balloons in either the LAD or LCX; and allows easy retraction and engagement of the guide, particularly during a PCI of ostial lesions.¹ 
7. Guide catheter extensions can be employed to extend the effective length of the guide catheter (e.g., in a dilated aortic root) or facilitate device delivery across tight or tortuous segments via deep coronary engagement.^1,6 Guide catheter extensions are 1 Fr size smaller than the corresponding guide catheter, designed to minimize risk of vessel injury. If there is no significant disease or significant tortuosity in the proximal vessel, the guide catheter extension can be advanced further into the coronary artery. Otherwise, positioning an uninflated balloon or an inflated “anchor” balloon (inchworm technique) ahead of the guide catheter extension can minimize risk of iatrogenic vessel injury.⁶ 

Conclusion 

Maximizing guide support is important in achieving successful PCI. A combination of different techniques can be employed, depending on the lesion characteristics and available equipment. Anticipating the need for additional guide support and learning these techniques are essential to safe and successful PCIs. 

References 

1. Nguyen TN, Chen SL, Kim M-H, et al. Practical Handbook of Advanced Interventional Cardiology: Tips and Tricks. Chichester, West Sussex, UK: John Wiley & Sons, Ltd; 2020. 
2. Ikari, Y. Long-Term Experience Using the Ikari Guide Catheter for Radial PCI. Cath Lab Digest. 2013 Sep;21(9). 
3. Watson TJ, Ong, PJL, Tcheng JE. Primary Angioplasty: A Practical Guide. Singapore: Springer; 2018. 
4. Ikari Y, Masuda N., Matsukage T, et al. Backup force of guiding catheters for the right coronary artery in transfemoral and transradial interventions. J Invasive Cardiol. 2009 Nov;21(11):570–574. 
5. Chawla R, Ahamad W, Sharma V. Techniques to Overcome Difficulty in Device Deliverability to Lesion in Complex PCI. Curr Cardiol Rev. 2020;16(2):117-124.  
6. Hellig F, van Wyk P, Moosa M. The Do’s and Dont’s of Guide Catheter Extensions. CIToday. 2020 Sep/Oct;14:44–47.