Commentary

The Guiding Catheter: The Most Underrated Asset to Coronary Angioplasty

Bernhard Meier, MD
Bernhard Meier, MD
It was the guiding catheter that prevented the successful clinical launch of percutaneous transluminal coronary angioplasty on March 22, 1976. The patient was afflicted with generalized atherosclerosis. His aorta was completely occluded. Andreas Gruentzig attempted coronary angioplasty to treat end-stage triple vessel coronary artery disease because the patient’s symptoms prevented his mobilization from the intensive care unit, and he had been turned down by the cardiac surgeons. The preliminary dog experiments were carried out with stiff 10 French (Fr) guiding catheters featuring a shape somewhere between a left Judkins catheter and a multipurpose catheter. Using the brachial approach, it proved impossible to cannulate the left main stem, thus the procedure was abandoned. No balloon catheter had been introduced, thus the procedure was not considered to be the first case of coronary angioplasty. It was not until a year and a half later (September 16, 1977) that coronary angioplasty was successfully performed for the first time.1 For a while, debates raged about whether the backup for balloon advancement (often the crucial determinant of success or failure when balloon profiles were bulky) was superior to the femoral approach, according to Judkins, or from the brachial approach, according to Sones. Personal and local preferences were developed and defended and were primarily based on the technique used for diagnostic studies. Some operators changed between the brachial and femoral approaches depending upon the patient’s anatomical situation. Over the subsequent decades, balloon catheters became slicker and guiding catheters smaller and softer. Each 1 Fr (0.33 mm) increment of downsizing guiding catheters was considered a welcome development for two reasons: 1) the access holes were smaller; and 2) the so-called coronary wedging problem (complete occlusion of the ostium of the coronary artery by the guiding catheter) became rarer. While the puncture hole was not an issue with the Sones technique (cut-down and suture in the elbow), it was an issue with the percutaneous femoral technique. On the other hand, there were always concerns that the backup power was no longer adequate. Favoring soft guiding catheters, I usually found that the smaller guiding catheters were better and presented no drawbacks. Some of my European colleagues supported this view as well. Many of my American colleagues generally relied on the intrinsic backup of the guiding catheter sitting in front of the ostium. They tended to reserve using the technique of deeply intubating guiding catheters to rare cases. The American approach required larger, stiffer guiding catheters. In situations where such catheters entered the ostium deeply, side holes were often needed to maintain coronary flow despite the snugly-wedged catheter. For a while, 6 Fr guiding catheters were the rule in many European centers, while American centers were still debating whether a general step down from 8 Fr to 7 Fr guiding catheters should be condoned. I used to joke during that period that all it took to perform coronary angioplasty was 6 Fr, with the exception of angioplasty performed by a French (which would then make it 7 French). This play of words emerged because of the general use of the term “French” instead of the original name “Charrière” as a unit size, probably because of the difficult pronunciation and spelling of the latter. In this issue of the Journal, Ikari et al. present a sophisticated analysis of the intrinsic (and position supplied) backup of 6 Fr, 7 Fr, and 8 Fr guiding catheters introduced through the leg or the arm, which helps operators decide what catheter size and shape are best to use and how much active positioning to employ. The brachial approach had all but completely disappeared for more than a decade. It enjoyed a resurgence thanks to a Dutch group2 whose work was based on preliminary research conducted in Canada.3 Again, the entry of the ascending aorta from the right subclavian artery, rather than from the aortic arch, called for modifications of catheter shapes and positioning techniques. Operators were intuitively selecting the appropriate shape and performing the appropriate maneuvers, but not without a period of trial and error. It is commendable to provide some scientific background, particularly as a means to avoid futile approaches that are bound to fail. Having performed all coronary angioplasty procedures using 5 Fr guiding catheters from the groin site for many years — more recently even without employing an introducer sheath to keep the access hole as small as possible (the sheath adds about 1.5 Fr to its labeled size, which refers to the lumen rather than the outside diameter) — the calculations presented by the authors are inapplicable. However, the majority of angioplasty operators are still using 6 Fr or larger catheters, and will continue to do so for quite some time, if not indefinitely. In addition, few operators are used to manipulating catheters like jugglers, mainly because they have not lived through the period of the Sones or Schoonmaker/King techniques in which multipurpose-type catheters were used for both coronary ostia (and for access to the left ventricle as well). The shapes of catheters examined here are common types. It could be considered regrettable that the most versatile of all catheters and the one with the longest history and outstanding intrinsic backup, i.e., the Amplatz catheter, has been ignored by the authors. The reason may be that this shape carries the stigma of an increased risk of ostial dissection. This catheter’s notoriety may have been deserved when the tips were hard and the diameters were large, although even at that time, its disadvantages were not conclusively demonstrated. With soft tips and small, flexible catheters, Amplatz-shaped catheters are no more dangerous than other shapes. The article by Ikari et al. can be recommended for beginners as well as for accomplished operators as a source of information on the physics that apply to coronary angioplasty interventions. Soft, pliable targets approached with soft, pliable equipment are difficult to predict in terms of their reaction. The authors’ recommendations may help, but they will by no means replace proper training in the presence of experienced interventional cardiologists on a large number of cases. Only this extensive training will guarantee that the new operator will become sufficiently familiarized with the necessary variety of materials and techniques that have stood the test of time. The coronary arteries to be repaired understand many interventional languages. It is enough to be fluent in a few of them. Even if some operators don’t understand the particular interventional language learned and practiced by a well-trained operator, the coronary tree will.
References
1. Meier B. Percutaneous coronary intervention. In: Topol EJ (ed). Textbook of Cardiovascular Medicine, 2nd edition. 2002, pp. 1665–1676. 2. Kiemeneij F, Laarman GJ, de Melker E. Transradial artery coronary angioplasty. Am Heart J 1995;129:1–7. 3. Campeau L. Percutaneous radial artery approach for coronary angiography. Cathet Cardiovasc Diagn 1989;16:3–7.