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Clinical applications of video angioscopy

1987; Elsevier BV; Volume: 5; Issue: 4 Linguagem: Inglês

10.1016/0741-5214(87)90250-3

1097-6809

Cornelius Olcott,

Aortic Thrombus and Embolism

The surgeon's interest in cardiovascular endoscopy dates back to 1913 when Rhea and Walker first described their experiences in dogs with direct intracardiac visualization (cited by Cutler et al.1Cutler EC Levine SA Beck CS The surgical treatment of mitral stenosis: experimental and clinical studies.Arch Surg. 1924; 9: 689-821Crossref Google Scholar). In 1922 Allen and Graham2Allen DS Graham EA Intra-cardiac surgery—a new method.JAMA. 1922; 79: 1028-1029Crossref Scopus (54) Google Scholar used a “cardioscope” for visualizing the cardiac chambers in humans and for assisting with mitral valve surgery. There was little experience with vascular endoscopy until 1966 when Greenstone et al.3Greenstone SM Shore JM Heringman EC Massell TB Arterial endoscopy (arterioscopy).Arch Surg. 1960; 93: 811-812Crossref Scopus (19) Google Scholar described their use of a flexible choledochoscope for viewing endarterectomized aortoiliac systems. Eleven years later, Towne and Bernhard4Towne JB Bernhard VM Vascular endoscopy—an adjunct to carotid surgery.Stroke. 1977; 8: 569-571Crossref PubMed Scopus (26) Google Scholar, 5Towne JB Bernhard VM Vascular endoscopy useful tool or interesting toy.Surgery. 1977; 82: 415-419PubMed Google Scholar described their experience with a rigid choledochoscope and an arthroscope as an adjunct to arterial reconstructive surgery. Other reports on the use of vascular endoscopy soon followed.6Volmar JF Storz LW Vascular endoscopy—possibilities and limits of its clinical application.Surg Clin North Am. 1974; 54: 111-122PubMed Google Scholar, 7Tanabe T Yokota A Sugie S Cardiovascular fiberoptic endoscopy: development and clinical application.Surgery. 1980; 87: 375-379PubMed Google Scholar, 8Itoh T Hori M Vascular endoscopy for major vascular reconstruction: experimental and clinical studies.Surgery. 1983; 93: 391-396PubMed Google Scholar In 1984 Grundfest et al.9Litvack F Grundfest WS Lee ME et al.Angioscopic visualization of blood vessel interior in animals and humans.Clin Cardiol. 1985; 8: 65-70Crossref PubMed Scopus (47) Google Scholar, 10Grundfest WS Litvack S Sherman T et al.Dilineation of peripheral and coronary detail by intraoperative angioscopy.Ann Surg. 1985; 202: 394-400Crossref PubMed Scopus (75) Google Scholar, 11Grundfest WS Litvack F Goldberg T et al.Pulsed ultraviolet lasers and the potential for safe laser angioplasty.Am J Surg. 1985; 150: 220-226Abstract Full Text PDF PubMed Scopus (118) Google Scholar began to report their experience with endoscopy in the peripheral and coronary circulation and to suggest its use in conjunction with laser angioplasty. Enthusiasm for vascular endoscopy between 1913 and now has been limited, primarily because the equipment has been cumbersome and the imaging inadequate. The endoscopes were too large for many of the vessels on which vascular surgeons were operating. Early endoscopes were rigid and lacked the maneuverability needed in dealing with tortuous vessels. There was no good way to keep blood out of the viewing field. The optics were not satisfactory and visualization of the vessel required direct contact with the eyepiece, which frequently led to breaks in surgical technique. Recently these problems have been addressed and are currently being solved by the manufacturers of endoscopy equipment. Small, flexible endoscopes with external diameters as small as 2.8 mm are now available. These endoscopes have three channels, one for a light source, one for optics, and one for irrigation or instrumentation. The problem of eyepiece contamination has been solved by the availability of small, lightweight cameras that attach directly to the eyepiece. The image is then transferred directly to a high-resolution color monitor that allows simultaneous viewing by the entire operating team. The images may also be relayed to a video recorder that can preserve the information for later use (e.g., teaching or legal documentation). We have had experience with two types of endoscopes. First is the rigid telescope such as that designed for use in bronchoscopy or arthroscopy. These devices are small (external diameters ranging from 2.3 to 4.0 mm) and come with two channels, one for light transmission and one for optics. The image with these devices is excellent, in fact usually better than with the flexible models. These endoscopes are advantageous because of their small diameter but are of limited use because they lack the third channel needed for irrigation or instrumentation and because they are not maneuverable or steerable. The second type of endoscope is the flexible one. These come in external diameters of 2.8, 3.7, and 4.5 mm (Olympus Corp. of America, Lake Success, N.Y.) and have three channels, for light, optics, and irrigation or instrumentation. We use a 1000 watt xenon light source (Olympus). The endoscopes are coupled to a lightweight video camera (Endovideo-II, Circon Corp., Santa Barbara, Calif.) from which images are relayed to a high-resolution color video monitor and recorded on a¾ inch cassette recorder (Circon Corp.). When one of the larger, flexible endoscopes is used, the field visualized is kept clear of blood by the simultaneous infusion of normal saline solution through one of the channels in the endoscope. The pressure of the infusate can be adjusted by using one of the pressurized intravenous infusing devices (C-Fusor, Medex, Inc., Hilliard, Ohio). There are several reasons to explore the clinical applications of video angioscopy. First is its use as an alternative to intraoperative angiography. The advantages of angioscopy have been well documented by Towne and Bernhard.4Towne JB Bernhard VM Vascular endoscopy—an adjunct to carotid surgery.Stroke. 1977; 8: 569-571Crossref PubMed Scopus (26) Google Scholar, 5Towne JB Bernhard VM Vascular endoscopy useful tool or interesting toy.Surgery. 1977; 82: 415-419PubMed Google Scholar Angioscopy provides the surgeon with a good, three-dimensional view of the reconstructed vessel before blood flow is restored. Any technical defects may be immediately, and if necessary repeatedly, corrected while the vessel is stil open. Angioscopy, unlike arteriography, does not require an x-ray technician or radiologist. This decreases both the operating room time and cost. In addition, exposure to radiation of the operating room personnel is eliminated. The one disadvantage of angioscopy is that it does not provide full visualization of the downstream vessels (e.g., the distal tibial-peroneal vessels below a femoropopliteal bypass). We have found video angioscopy to be useful in the evaluation of the endarterectomized carotid artery, profundaplasties, renal and visceral artery reconstruction, graft thrombectomies, and revision of bovine fistulas. A second and increasingly useful role of video angioscopy is in the preparation of the saphenous vein for its use as a “nonreversed” vein graft for lower extremity revascularization. Direct visualization of the valves allows for accurate destruction of the valve cusps without injury to other portions of the vein. A third and important role of video angioscopy is its potential role in new vascular reconstructive techniques. Much work is being done to develop alternatives to standard reconstructive procedures; these include balloon angioplasty, laser angioplasty, and catheter athrectomy. These techniques are particularly important in today's medical-economic climate as they have the potential to simplify and to lower the cost of vascular surgery. Common to all these “high-tech” advances is the need to accurately and easily visualize the operative field. Video angioscopy can be of great help in this regard. With these factors in mind, we have been attempting to establish a workable video angioscopy system that can be easily used by the clinical vascular surgeon. We believe that this will be of immediate benefit in improving surgical technique and results and will be of long-term benefit in allowing vascular surgeons to better employ the new vascular techniques that are on the horizon. We have recently reported on our experience with video angioscopy as an alternative to intraoperative angiography.12Mehigan JT Olcott C Video angioscopy as an alternative to intraoperative arteriography.Am J Surg. 1986; 152: 139-145Abstract Full Text PDF PubMed Scopus (43) Google Scholar We have continued to increase our experience with this technique. Between August 1985 and June 1986, video angioscopy has been used in 78 procedures, which include 24 carotid reconstructions, 23 femoropopliteal or femorotibial reconstructions, three graft thrombectomies, six renal artery reconstructions, three bovine revisions, and 14 aortofemoral or iliofemoral reconstructions. All femoropopliteal or femorotibial reconstructions were performed with a nonreversed saphenous vein graft. The valves in these vein grafts were bisected under direct vision by means of video angioscopy and a Leather valvulotome. In all of the reconstructive procedures, video angioscopy was used instead of intraoperative arteriography. The appropriate area (e.g., the endarterectomized portion of the carotid artery or the distal anastomosis of a femoropopliteal reconstruction) was viewed directly through the arteriotomy or anastomosis while saline solution was infused simultaneously to provide a fluid medium for optimal viewing. Any technical deficiencies were easily identified and corrected. In approximately half of these cases, the findings at angioscopy were significant to the point that technical corrections were made at the time of the procedure. In some cases we have been unsure of the importance of the findings at the time of angioscopy. The clarity of the image and magnification make even the smallest irregularities appear onerous. There were no complications attributable to the use of video angioscopy. Several problems still remain. In order for video angioscopy to be accepted by the practicing vascular surgeon, it must be quick to set up and easy to use. The endoscopes must be made in smaller diameters so they can be used in small vessels, but the quality of the optics must be preserved. The steering capabilities and orientation must be improved so that one may easily see both straight ahead and at angles, while at the same time maintaining proper orientation. The technique of saline infusion needs improvement, especially in those cases where it is necessary to prevent back-bleeding. Despite these problems, we believe video angioscopy has come of age. The equipment is constantly improving and has now reached the point where one can obtain an excellent image that may be easily displayed on a monitor and simultaneously recorded. Video angioscopy serves as an excellent, possibly preferred, alternative to intraoperative angiography. It has proved to be extremely helpful in preparation of the saphenous vein graft and will, we believe, be useful as an adjunct to balloon angioplasty, laser angioplasty, and catheter athrectomy.