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Long-Term Experience Using the Ikari Guide Catheter for Radial PCI
Introduction
There is no doubt that a guiding catheter is important for successful percutaneous coronary intervention (PCI). The radial approach to PCI is being rapidly adopted around the world, and is gaining greater acceptance in the United States. This alternative approach presents a new set of challenges for the guide catheter and the cardiologists. Therefore, it may be necessary to review the basic principles behind guide catheter selection, and the requirements for backup support, coaxial engagement and the resulting procedural success that can be achieved when using a catheter specifically designed for access from the right radial approach. Coronary dissection is a serious complication caused by an inappropriate guiding catheter, especially at the left main. Our extensive experience with the Ikari guide catheter has demonstrated no dissections.
Transradial intervention (TRI) using the right radial artery as an approach site is a relatively new method to many physicians. Many benefits of TRI have been reported such as lower major bleeding complications, no need for bed rest after the procedure, less neurologic complications, shorter hospital stay, lower subjective pain, fewer resources, and a higher level of patient satisfaction. Specifically, TRI can reduce the mortality rate of patients with ST elevation acute myocardial infarction (STEMI) in TRI high-volume centers.1 However, many doctors do not prefer TRI. One reason that has been identified relates to the challenges encountered in guiding catheter manipulation, and how different/challenging it is from the guiding catheter manipulation encountered during transfemoral intervention (TFI); thus the reluctance regarding the TRI approach. This can be a compelling reason to perform TFI, not TRI, because PCI success is the first priority. However, a better understanding of how certain guide catheters peform and how to choose the appropriate guide catheter when approaching from the right radial will help ensure a better, safer outcome in TRI procedures.
Left coronary artery
Guiding catheter performance can be assessed based on three factors: 1) easy and fast engagement without specific manipulation, 2) strong backup force, and 3) safety (not causing complications such as coronary dissection). An ideal guiding catheter should be easy, strong
and safe.
The Judkins left (L) catheter is an excellent catheter because of its easy engagement and safety. However, the Judkins L backup force in TRI is not strong, despite its perfect balance in TFI. Why is the backup force of the Judkins L in TRI weak? A study on the physics of backup force in a guide catheter can answer this question (Figure 1).2 It showed that the angle between the catheter and the reverse side of the aorta is a factor in determining backup force. The Judkins L loses its angle-generating backup force when it is applied in TRI (Figure 2). Thus, the weak backup force in TRI is not a general TRI problem, but a Judkins-specific problem in TRI.
Thus, we need a radial approach catheter with an engagement maneuver that is as easy and safe as the Judkins L, but with stronger backup force than the Judkins L catheter. Does a catheter like that really exist?
The Ikari left guiding catheter concept
The Ikari left (L) guiding catheter was invented in 1995, first applied to PCI in 1996, and commercially available in 2002.3,4 The Ikari L catheter has three modifications from the Judkins L: 1) a shorter length between the third and the fourth angles, 2) longer length between the
second and the first angles, and 3) the new first angle was added to fit the brachiocephalic artery (Figure 3). The Ikari L is essentially a modified version of the Judkins L catheter for TRI. Due to the modifications, the backup force of the Ikari L is stronger than the Judkins L in TRI, because the angle between the Ikari L catheter and the reverse side of the aorta is bigger than with the Judkins L. The Ikari L in TRI is actually stronger than the Judkins L in TFI.
How to engage the Ikari L guiding catheter: The maneuver is basically same as with the Judkins L. Advance the catheter slowly into left coronary cusp; it can engage the left coronary artery without any additional manipulation. You will not feel the difference between the Ikari L and Judkins L, despite the fact that the Judkins L in TRI is not like the Judkins L in TFI. There is only a small difference in the gradual angle at the reverse side of the aorta compared with the Judkins L. However, this difference enhances safety because the motion of the engagement slows due to the gradual angle, which can help minimize the injury to the left main. I have trained many people on how to use the Ikari L; however, no words are necessary for operators familiar with the Judkins L catheter, because of the same engagement manipulation.
You will find surprisingly stable engagement with the Ikari L, without deep engagement. When you push a stent or balloon into a tight lesion with tapping, the Judkins L complicates collapse of the entire system.* However, the Ikari L stays engaged and generates backup force even in this situation.
Tips to increase backup force in the Ikari L (power position):
Occasionally, a stronger backup force is necessary for an extremely complex lesion. There is an easy method of manipulation to increase backup force in the Ikari L. This technique is as easy as
pushing the guiding catheter up to the reverse side angle of 90 degrees (Figure 4). At this point, the backup force becomes much more significant. Deep engagement of the Judkins L also generates greater backup force; however, this can sometimes damage the left main. However, the power position with the Ikari L is safe, because the distal tip is never inserted deeply due to its differentiated design. To date, no left main dissections with Ikari L have been reported in our database (>1000 cases) and in the reports from Youssef et al (>600 cases)5, or other studies6.
Comparison between Ikari L and Extra back up (EBU)/Xtra backup (XB) catheters
Guiding catheters can be divided into active or passive manipulation types. The EBU/XB-type guide catheters are passive and this may explain why they are utilized so extensively, whereas the Ikari L or Judkins L is an active-type catheter.
What is the benefit of the passive guide catheter? It is not necessary to touch the guide catheter during the procedure. PCI operators are busy concentrating on manipulating other devices, such as guide wires and balloon catheters, and therefore, don’t want to have to worry about the guide catheter. Furthermore, they have to pay attention to the ECG monitor and blood pressure, so not manipulating a guiding catheter after engagement can reduce the burden during the procedure.
What is the disadvantage of the passive-type guiding catheter? Common passive guide catheters are EBU/XB catheters for the left coronary artery and the Amplatz L for the right coronary artery. Note that these catheters are long-tip catheters. Engagement of long-tip catheters is more difficult than short-tip catheters. Deep insertion is inevitable with the long-tip catheters, which poses higher risk for coronary dissection. Careful engagement is necessary. However, after safe engagement of the guide catheter, the long-tip catheter can automatically advance deeper over the guide wire or during balloon catheter removal without any operator manipulation. Operators cannot control the automatic advancement of the catheter as the counteraction of pulling devices. If there is a plaque at the proximal coronary artery, there is no way to avoid coronary dissection except to avoid using long-tip catheters.
What is the benefit of the Ikari L type guide catheter? Engagement is just as easy as with the traditional Judkins L. When a strong backup force is necessary, you can make a power position that is directly within the operator’s control. One may have concern about coronary dissection at the power position. However, our observations on many cases show that the power position of the Ikari L is not a deep insertion of the catheter. The distal tip does not move with this maneuver, because of its sophisticated design. Even at the power position, the catheter tip of the Ikari L is still outside the original position of the EBU/XB-type catheters. No left main dissection caused by an Ikari L has been reported in our database (>1000 cases) and in the reports from Youssef et al (>600 cases)5. Thus, we find the Ikari L to be very easy and most of all, very safe.
Still, some operators may not prefer the Ikari L because they have to manipulate the guiding catheter during PCI. But what is the priority in PCI? Safety is and should be the number-one priority. The left main dissection rate is one of the greatest factors to consider when choosing a guide catheter. For operators with concerns about pushing the Ikari L catheter to achieve the power position, we recommend learning more about the Ikari L catheter. Operators will be satisfied with controlling the guide catheter position with perfect safety during the procedure. The Ikari L is a controllable catheter, allowing operators to avoid risks even with strong backup force.
Right coronary artery
The Judkins right (R) is a standard catheter for the right coronary artery in the transfemoral approach. Benefits of the Judkins R include easy engagement and safety. However, in TRI, the Judkins R moves differently, because of its different engagement manipulation and weak backup force. Thus, we need a catheter like the Judkins R, but one that is suitable for TRI.
The Ikari L for the right coronary artery
The Ikari L was originally designed for the left coronary artery, but it is also good for the right
coronary artery. The shape of the catheter looks like the Judkins R if a 0.035-inch guidewire is inserted (Figure 5). Thus, catheter manipulation for engagement is similar to the Judkins R. Once the guide wire is removed, the catheter will engage the right coronary artery in a stable position. When strong backup force is necessary, you can facilitate a power position using the Ikari L catheter. Thus, the Ikari L is a strong type of Judkins R catheter for TRI.
In vitro experiments showed that the Ikari L in the power position can generate the strongest backup force among the Judkins R, Amplatz L, Ikari R, and Ikari L catheters (Figure 6).7 Also, we can say that the Ikari L is an easy, safe and strong catheter for the right coronary artery.
Note that the Ikari L in the right coronary artery may engage deeply at the power position. It does not happen in the left coronary artery, but you should be careful in the right coronary artery. But
you can still control the catheter position, which is different from long-tip catheters. Youssef et al reported that the right coronary artery dissection was 0.4% using the Ikari L catheter.5 It happened in the first 300 cases; however, there was no dissection in the second 300 cases. It suggests that there was a learning curve for safe Ikari L use for the right coronary artery.
Comparison between the Amplatz L and Ikari L for the right coronary artery
The Amplatz L is a passive-type catheter good for the right coronary artery. It is a long-tip catheter and can therefore be inserted deeply into the coronary artery unintentionally. This can mean a higher risk for coronary dissection. The Ikari L has a similar shape to the Judkins R. When used in a passive way, engagement manipulation of the Ikari L is like the Judkins R, but its backup force is stronger. If greater backup force is necessary for severe lesions, it is easy to obtain the power position by pushing the catheter along the guide wire. An in vitro study showed that backup force of the Ikari L at the power position was stronger than any other catheters, including the Amplatz L.
Benefits of both right and left coronary artery
Ikari L is a catheter for both the left and right coronary artery. What is the benefit of a switch-hitter? One great benefit is lower cost, because it is a single-catheter procedure. Second, TRI is considered to have benefits, specifically in patients with ST elevation myocardial infarction (STEMI). The RIVAL study showed that clinical outcomes were similar between TRI and TFI,
despite the longer door-to-balloon time in TRI. The benefits were clear in TRI high-volume centers. This suggests that we should shorten door-to-balloon time by acquiring better skills in TRI. A smart way to reduce door-to-balloon time is to use the Ikari L catheter.8 Only a single catheter is necessary to perform coronary angiography, both for the left and right coronary artery, and for PCI of the culprit lesion, found in either the right or left coronary artery. Operators can cut the catheter exchange time, which shortens door-to-balloon time. In our institute, the TRI door-to-balloon time is shorter than the TFI door-to-balloon time. Reduced catheter manipulation can also minimize potential radial artery spasm. Thus, the Ikari L, both for left and right coronary arteries, is an ideal catheter for STEMI.
Size of the Ikari L
The Ikari L 3.5 is a regular size catheter. Most cases can be done successfully with the Ikari L 3.5. The Ikari L 4.0 fits an elongated aorta, found in severe atherosclerotic patients such as old, hypertensive patients, or patients with diffuse and complex coronary disease. Since I only perform PCI for complex cases in our institute, I frequently use the Ikari L 4.0 catheter. However, I would suggest the Ikari L 3.5 for your first experience.
In cases of a short left main, the catheter tip may get into the left anterior descending (LAD) or circumflex (Cx) artery. If the tip is not inside the target vessel, what should we do? I suggest using the Ikari L. If the tip is inside the LAD, but you want to go to the Cx, choose one size up, from an Ikari L 3.5 to an Ikari L 4.0. If the tip is inside the Cx, but you want to go to the LAD, choose one size down.
Other applications of the Ikari L
The Ikari L can be used in any problematic situation such as high take-off vein grafts, right coronary artery originating from the left coronary cusp, or dextrocardia.9 If you have trouble engaging the guiding catheter in TRI, I suggest using the Ikari L.
Summary
The Ikari L is a modified Judkins L type catheter for TRI. It is safer than long-tip catheters in terms of lower left main dissection. Backup force is similar to or better than EBU/XB-type catheters. The Ikari L can be used for the right coronary artery and is stronger than any other catheters. Especially for patients with STEMI, the Ikari L is an ideal guiding catheter, because door-to-reperfusion time is shortened through the elimination of catheter exchange time via a single-catheter procedure.
Dr. Yuji Ikari may be contacted at ikari@is.icc.u-tokai.ac.jp.
References
- Mehta SR, Jolly SS, Cairns J, Niemela K, Rao SV, Cheema AN, et al; Effects of radial versus femoral artery access in patients with acute coronary syndromes with or without ST-segment elevation. J Am Coll Cardiol. 2012 Dec 18; 60(24): 2490-2499. doi: 10.1016/j.jacc.2012.07.050.
- Ikari Y, Nagaoka M, Kim JY, Morino Y, Tanabe T. The physics of guiding catheters for the left coronary artery in transfemoral and transradial interventions. J Invasive Cardiol. 2005 Dec; 17(12): 636-641.
- Ikari Y, Nakajima H, Iijima R, Aoki J, Tanabe K, Nakayama T, et al. Initial characterization of Ikari Guide catheter for transradial coronary intervention. J Invasive Cardiol. 2004 Feb;16(2): 65-68.
- Ikari Y, Ochiai M, Hangaishi M, Ohno M, Taguchi J, Hara K, et al. Novel guide catheter for left coronary intervention via a right upper limb approach. Cathet Cardiovasc Diagn. 1998 Jun; 44(2): 244-247.
- Youssef AA, Hsieh YK, Cheng CI, Wu CJ. A single transradial guiding catheter for right and left coronary angiography and intervention. EuroIntervention. 2008 Jan; 3(4): 475-481.
- Matsukage T, Yoshimachi F, Masutani M, Katsuki T, Saito S, Takahashi A, et al. A new 0.010-inch guidewire and compatible balloon catheter system: the IKATEN registry. Catheter Cardiovasc Interv. 2009 Apr 1;73(5): 605-610. doi: 10.1002/ccd.21880.
- Ikari Y, Masuda N, Matsukage T, Ogata N, Nakazawa G, Tanabe T, Morino Y. Backup force of guiding catheters for the right coronary artery in transfemoral and transradial interventions. J Invasive Cardiol. 2009 Nov; 21(11): 570-574.
- Chow J, Tan CH, Tin AS, Ong SH, Tan VH, Goh YS, et al. Feasibility of transradial coronary angiography and intervention using a single Ikari left guiding catheter for ST elevation myocardial infarction. J Interv Cardiol. 2012 Jun;25(3): 235-244. doi: 10.1111/j.1540-8183.2011.00710.x.
- Ishiguro H, Murohara T, Ikari Y. The feasibility of using Ikari left catheter via the right radial approach in a patient with dextrocardia for better guiding support. J Invasive Cardiol. 2011 Dec; 23(12): E288-E290.
Commentary
Mauricio G. Cohen, MD, FACC, Associate Professor of Medicine, Miller School of Medicine, University of Miami, Medical Director of the Elaine and Sydney Sussman Cardiac Catheterization Labs, University of Miami Hospital, the flagship facility of UHealth – University of Miami Health System, Miami, Florida
The rate of adoption of transradial (TR) catheterization and interventions has been slowly rising in the United States over the past decade. In certain geographic areas, such as the northeastern U.S., TR use is close to 25%. As operators become more comfortable with the technique and more training programs incorporate TR access into their curriculum, adoption rates are expected to increase exponentially. An initial good step in the learning process is to use catheter shapes that are familiar to the femoral operator, such as Judkins right and left, during diagnostic procedures. As operators gain experience, the next step is to try universal shapes such as Tiger, Jacky, and other catheters that allow engagement of both coronary arteries. Universal catheter shapes offer the advantage of decreasing procedural time and the probability of vasospasm by sparing a catheter exchange. Experienced operators have a good understanding of the anatomy and are able to select the catheter that best fits the coronary ostia in the individual patient. Experienced operators also understand the physics of catheter manipulation and backup support. For TR coronary interventions, the Ikari left catheter represents a convenient solution. In his article, Dr. Ikari makes a thorough description of the Ikari left catheter in comparison with standard catheters such as Judkins right and left, extra backup, and Amplatz, and makes a strong argument for the benefits of using the Ikari left catheter. However, in transradial catheterization practice makes perfect, and I have observed that operators usually stick with the catheter shapes that they dominate best and that provide the best results in their hands.
In my experience, I have found the Ikari catheter to be valuable in primary percutaneous coronary intervention (PCI). In Miami-Dade County, the Emergency Medical Services keeps track of door-to-coronary device times very carefully across hospitals participating in the countywide ST elevation myocardial infarction (STEMI) network. Hospitals unable to maintain a minimum standard of door-to-device time of less than 90 minutes are automatically excluded from the network. In this environment, every minute counts. Opinions are divided on the best approach to STEMI intervention. Recent data shows substantial outcomes benefit in STEMI patients for transradial access. In terms of procedural aspects, many operators advocate injecting the non-culprit vessel first in order to have a full understanding of the coronary anatomy before deciding on the interventional approach, while others feel that going after the culprit vessel first saves precious time. In a recent study, injecting the non-culprit vessel before PCI is associated with an average delay of 8 minutes in comparison to direct treatment of the culprit lesion. A universal catheter such as the Ikari left, that allows quick angiographic views of both vessels and provides good support for PCI, is an excellent choice in the primary PCI setting and saves time.
The technical tips and tricks described by Dr. Ikari are valuable for the radial operator who needs to become familiar with different families of catheters. The more informed and experienced the operator, the better the outcomes. In fact, operators should develop their own menu of guiding catheters that best suit the particular intervention at hand and some may indeed find that the Ikari left meets their definition of a workhorse catheter.
