Experiences with rotation atherotomy and atherectomy
Steckmeier, B.; Baumgart, R.; Küffer, G.; Schweiberer, L.
Herz 14(1): 43-51
1989
ISSN/ISBN: 0340-9937 PMID: 2522080 Document Number: 343964
In addition to currently available, low risk procedures for reestablishment of patency in arteriosclerotic vascular segments with bougier techniques as described by Dotter and the balloon dilatation modification according to Gruntzig, as necessary together with local thrombolysis, important new developments based on mechanical principles are the atherectomy according to Simpson as well as the rotation atherotomy with a flexible catheter and slowly rotating milling head or rapidly rotating head as used by Kensey. To provide a larger lumen of recanalization, we developed an atherotomy lathing catheter with a rapidly rotating head and various diameters which is now available for intraoperative use. The thrombendarterectomy as described by Vollmar with the "ring stripper" is used only intraoperatively and can only be performed retrograde. The effect of laser systems encompasses disintegration and ablation of occlusive material. The rotation atherotomy is based on the capability of discrimination between hard occlusive material and elastic vascular wall through suitable construction of the lathe head. Since, in passive catheters, the capability of lathing at the tip is associated with a high risk of perforation and a lateral possibility for lathing is not achievable, the lathing performance should be small, at the center of rotation and orthogonal to the axis rotation at the outer radius. Through combination with a spherical disc face perpendicular to the axis of rotation, which protrudes only slightly from the hemispherical catheter tip, with a maximum at the center and minimum at the lateral borders, the lathing head has only a slight risk of perforation and no undesired sheering forces. The optimal lathing procedure is characterized by the proper choice of lathing head geometry and velocity of rotation, where the mechanism of action is based on an atraumatic removal of the occlusive material. Since with suitable dimensions of the lathe head, the debris consists of particles on the average less than 7 .mu.m, only isolated, clinically not relevant emboli are incurred. The prototypes developed function at 10,000 to 50,000 r.p.m. The catheter we have developed should be introduced 3 to 4 cm distal to the origin of the artery femoris profunda, after placement of a tourniquet, through a lateral incision. Accordingly, perfusion of the leg is via collaterals. To avoid emboli, in occlusions longer than 5 cm, the recanalization is performed stepwise and, when necessary, prior to re-establishing patency in the last segment, a Fogarty maneuver is incorporated. With this catheter, in seven of ten patients in stages III and IV, successful recanalization was achieved. For the use of the rotation lathe catheter, establishment of the indication should still be restrictive since too little experience is available to assess accurately the relevance of the debris. Its use appears promising for complete occlusion which cannot be passed by a guidewire and with adequate run-off. On intraoperative use, if necessary, after unsuccessful atherectomy a bypass graft can be constructed or, if the debris consists of particles between 10 and 100 .mu.m, they can be removed with a Fogarty catheter. The Simpson atherectomy catheter consists of a windowed-metal housing with a centrally-rotating, displaceable blade which is driven by a long flexible shaft. Juxtaposed to the cutting blade is an inflatable balloon. A flexible guidewire at the tip of the metal housing enables intraluminal steering. After introduction of the catheter with sheath technique, the metal housing is positioned through inflation of the balloon with the obstructive plaque at the opening. At 2,000 r.p.m. the cutting blade is activated and the debris is stored in the bow of the housing. The catheter is available in sizes 7, 9 and 11 French. With this catheter, successful treatment was performed in 17 patients with 23 stenoses in the femoro-popliteal vessels and four stenoses in the pelvic region; three of the pelvic stenoses required redilatation. Histologic studies of the desobliterated material showed circumscript fibrosis and widening of the intima. The Doppler index increased in eleven patients treated only with atherectomy from 0.64 .+-. 0.14 to 1.0 .+-. 0.06. There were no dissections or perforations. In association with one exulcerated, long-segment stenosis a hemodynamically-insignificant embolus was incurred. Follow-up observations from four to 44 weeks showed no residual stenoses. Since the first clinical trials in 1986, now more than 130 patients have been treated with the atherectomy catheter. After atherectomy, the vascular walls appear smooth and, typically, with no tears in the intima. The indication appears established for excentric, calcified or exulcerated plaques as well as for residual stenoses after ballon dilatation or dynamic rotation catheter angioplasty when the stenosis cannot be passed by the guidewire. The atherectomy is now regarded as c omplimentary to conventional PTA methods and promises to improve further the results of percutaneous transluminal angioplasty.