Informal Discussion

From to Angioscopy: Informal Discussion

Bruno S. Cortis, M.D., David M. Harris, Ph.D.,* and Joseph Principe, B.S.

Devices for visualizing blood vessels have evolved from a rigid, illuminated tube (1913), to a tube with an added convex lens (1922), to one with a transparent inflatable balloonfor displacing bloodfrom the line ofvision (1943), to aflexible angioscope (1960s). Recentfiberoptic developments make it possible to visualize the orifices ofthe coronary and simultaneous laser . The characteristic fluorescence ofhematoporphyrin derivative under ultraviolet light has been visualized angioscopically in experimental atheroscleroticplaque, where it accumulates and acts as a marker. However, several requirements need to be met in orderfor angioscopy to fulfill its therapeutic possibilities in angioplasty, thrombolytic therapy, intraoperative inspection of vascular anastomoses, and its diagnostic potential in distinguishingplaquesfrom clots andpulmonary embolisms from other obstructions. These requirements are: (1) variously-sized angioscopes to accommodate iliac, femoral, renal, and coronary arteries; (2) percutaneous introducers in the various sizes to prevent back-bleeding; (3) a more flexible, easily manipulated fiberoptic; (4) a sufficiently inflatable balloon tip; (5) cross hairs and reference points in the optical system; and (6) optimalfocal lengthsfor the areas to be visualized. Texas HeartInstitute Journal 1986; 13.281- 289) Key words: Angiography; angioscopy; fiberoptic developments

SINCE 1913, WHEN Rhea andWalker first Trimedyne Optiscope (Trimedyne, Inc., Santa inserted their rigid, illuminated tube into Ana, California), the more recent American a heart at thoracotomy,' devices for the vis- Edwards Mini-Flex Angioscope, whose inves- ualization of blood vessels have undergone tigational model was brought out by American considerable development and ingenious new Edwards Laboratories (Santa Ana, California) techniques, which have been revised and in November, 1983, and the #5 Olympus refined. In this article, we propose to review Ultrathin Fiberscope (Olympus Inc., New the history of various instruments introduced York, NewYork). In addition, we shall discuss over the years and to discuss experiences the Japanese Sumitomo Angioscope, which I during 2 years of study with currently availa- (the senior author of this article) had the ble technology in the United States: the opportunity to observe in the summer of 1984

From the Chicago MedicalSchool and the Department ofOtolaryngology-HandS, University ofIllinois and Wensky Laser Center, Chicago, Illinois. Address for reprints: Bruno S. Cortis, M.D., 7605 112 West North Avenue, River Forest, Illinois 60305. lxas HeartAHInstitutetioJoumal ypo to Angioscopy 281 while visiting the research laboratories of Dr. The next significant advance in the develop- Inoue in Tokyo, and assisting in studies using ment of angioscopic techniques was replace- this instrument. ment of the rigid instrument with a flexible one, which could be used for studying the HISTORICAL REVIEW aorta and its branches as well as the venous system.4'5 This application was useful mainly In 1913, Rhea and Walker' first introduced in cases of phlebothrombosis. the concept of an instrument to intraopera- In 1980, Moser and Shure6 used a 4 mm tively visualize the chambers of the heart. In bronchoscope to detect experimentally- 1922, Allen and Graham2 added a convex lens induced pulmonary emboli in dogs, and to the distal end of Rhea and Walker's rigid, showed the possible application of this tech- illuminated tube, which could be applied nique for diagnosis of pulmonary embolism. directly against the walls of the heart. How- In 1983, Spears et al,7 using a 1.8 mm ever, the interference of blood in the line of Olympus Ultrathin Fiberoptic Angioscope, vision remained a persistent problem for the visualized the orifices of the coronary arteries in next 20 years. dogs and in postmortem humans intraopera- Then, in 1943, Harken and Glidden3 put a tively. More recently, during cardiac catheteriza- transparent balloon at the distal end of the tion in humans, such visualization was angioscope. When the balloon was inflated, accomplished without reported complications. the blood was displaced allowing intracardiac My colleagues and I used the Trimedyne visualization. Optiscope (Fig. 1) to visualize the aortas and

FIg. 1 lThmedyne Optiscope (Thmedyne, Inc., Santa Ana, California).

Fig. 2 #5 Olympus Ultrathin Fiberscope (Olympus, Inc., New York, New York).

282 Angiography to Angioscopy ibl. 13, Dio. 3, September, 1986 Fig. 3 Orifice of a canine left coronary viewed Flg. 4 Bifurcation of a canine coronary artery viewed through the #5 Olympus Ultrathin Fiberscope. through the #5 Olympus Ultrathin Fiberscope. coronary arteries in vivo in dogs and rabbits, Inoue's group used a catheter with a trans- and in postmortem humans.8 For the past several parent balloon at the distal end and photo- months, we also have used the newly developed graphed the chamber wall with a high-speed #5 Olympus Ultrathin Fiberscope (Fig. 2) in camera at the moment of balloon inflation. dogs, both postmortem and in vivo. Figure 3 As early as 1982, Lee et al'3 (the Trimedyne shows the inner structure of a canine left coro- Company) described a laserscope as a flexible nary artery orifice viewed through the Ultrathin fiberoptic scope for directing a beam of laser Fiberscope. Figure 4 shows the inner structure energy under direct vision. A channel in the of a canine coronary artery bifurcation also Trimedyne instrument accommodates an viewed through the Ultrathin Fiberscope. Argon laser fiber that can be used for illumina- The Cedars-Sinai Medical Center, Los tion and for laser beam simultaneously. The Angeles, headed by Forrester,9 monitored the company now plans clinical trials under their circulation of the coronary and peripheral Laserscope Certification Program, dependent vessels by intraoperative vascular upon FDA approval. They use the Trimedyne with both American Edwards and Trimedyne Laserscope system to study laser angioplasty instruments (outside diameter: 1.5, 2.5, and techniques. The FDA has approved the use of 3.7 mm). Myler, Stertzer et all' inspected the laser by certain institutions in connection patients undergoing iliac angioplasty by using with peripheral bypass . During angio- a Trimedyne Optiscope with a 3 mm outside scopy, an angiograph also can be made, and in diameter fiberoptic. Where conventional some cases, having both endoscopic and angiography showed a smooth lumina after the radiographic images may be advantageous. angioplasty, detailed angioscopic visualiza- tion revealed fibrin strands, atheromatous RECENT DEVELOPMENTS material, and shagginess of the vessel wall at the operative site, in contrast to smoothness of Although angioscopy is still experimental, a the vessel wall at adjacent sites. wide range of clinical applications have been Inoue et al,""2 using a Sumitomo Angio- envisioned for this technique. Among those scope (Fig. 5), visualized experimental arte- deserving the most immediate study may be rial endothelial lesions and vascular thrombi in the inspection of vascular anastomoses at the vivo in dogs. The cardioscope was French #5, time of the procedure to discover the existence and they used 160-cm-long catheters in French of any intimal flap for correction. This could sizes 7, 8, 9, and 14. For intracardiac study, possibly eliminate the need for angiography. In

Texas Heart Institute Journal Angiography to Angioscopy 283 , ;._..

Fig. 5 Sumitomo Angioscope (Japan). Left: (1) Catheter, irrigation channel; (2) Connection to light source; (3) Eyepiece-camera connection; and (4) TV camera connection. Right: (1) Close-up of catheter tip (distal end). (By courtesy of Drs. Inoue and Kuwaki).

Fig. 6 American Edwards Mini-Flex Angioscope (American Edwards Laboratories, Santa Ana, CA). peripheral angioplasty, angioscopy can be vessels. They reported seeing the following used before and after the procedure to reduce fine details not previously seen: (1) fatty occlusive phenomena. Thrombolytic therapy streaks, ulcerations and atheroma; (2) occlu- can be tailored to the individual patient by sive and nonocclusive thrombi; (3) damaged angioscopically visualizing the vessel's inti- saphenous valves; (4) lesions proximal mal layer before and after the treatment. and distal to anastomosis; and (5) suture lines In the forseeable future, angioscopic inspec- on the luminal surface.9 tion may provide a definitive diagnosis of Spears, Serur et al'4 have shown in studies certain conditions: the direct vision of a with experimental animals that hemato- problem area may enable plaques to be distin- porphyrin derivative is a useful marker for guished from clots. Forrester, Grundfest et a19 neoplasms because it accumulates and glows have studied intravascular images of the under ultraviolet light. The hematoporphyrin coronaries, bypass grafts, dialysis access derivative also accumulates in atheroma- fistulas, iliofemoral systems, and native tous plaques in experimental animals. This

284 Angiography to Angioscopy Vol. 13, No. 3, September1986 Flg. 7 Magnified view of rabbit abdominal aorta with whitish areas of atherosclerotic plaque.

.. 'a. -.*

. V.. 'I'm.- . . 'I b.S .1' Flg. 8 Same as Figure 7 under ultraviolet light. Red areas are porphyrin-produced fluorescence.

Fig. 9 Same aorta as in Figure 7 viewed through the Fig. 10 Same as Figure 9 under ultraviolet light. Pink angioscope. areas are porphyrin-produced fluorescence.

Texas Heart Inttute Journl Angiography to Angioscopy 285 Fig. 11 TNo routes of catheterization: via the arm and via the leg. In catheterization via the leg, the scope can be advanced either up toward the heart or down toward the peripheral artery being studied. porphyrin-produced fluorescence can be areas of atherosclerotic plaque. Figure 8 visualized angioscopically in experimental shows the same view under ultraviolet light. atherosclerosis in rabbits, as my colleagues The red areas are porphyrin-produced fluo- and I have demonstrated in our studies with the rescence. Figure 9 shows the same aorta Trimedyne Optiscope (Fig. 1) and the viewed through the angioscope, and Figure American Edwards Mini-Flex Angioscope 10 shows the angioscopic view under (Fig. 6).15 Figure 7 shows a direct magnified ultraviolet light. Pink areas are porphyrin- view of a rabbit abdominal aorta with whitish produced fluorescence.

286 Angiography to Angioscopy Vol. 13, No. 3, September, 1986 Thus the path is clear for the development SURVEY OF INSTRUMENTATION of angioscopic techniques in the diagnosis of atherosclerosis, the monitoring ofthis disease, As mentioned, the Trimedyne Optiscope, the study of effects of lipid-lowering agents, the #5 Olympus Ultrathin Fiberscope, the and the evaluation of angioplasty procedures. Sumitomo Angioscope (Japan), and the Amer- In addition, since angioscopic techniques may ican Edwards Mini-Flex Angioscope are provide the perfect visual control demanded shown in Figures 1, 2, 5, and 6, respectively. by the use of the laser to photoatherolize Characteristics of the angioscopic instruments plaques, further developments may facilitate generally available in the United States at its use to recannalize occluded vessels. Forrester present, namely the Trimedyne Optiscope and et al'6 used a prototype laser-angioscope to the American Edwards Mini-Flex Angio- successfully deliver varying doses of laser scope, are compared in detail by Ledor et al'8 energy to femoral artery segments in dogs in in their report on the state of angioscopic vivo, thus demonstrating the feasibility of technology. The American instruments require restoring vascular patency by laser energy several modifications if they are to fulfill the directed visually throughfiberoptic angioscopy. prodigious estimates of their future usefulness In pulmonary diagnosis, angioscopy can be in clinical practice. used to distinguish patients with pulmonary A percutaneous introduction device is embolism from those with pulmonary arterial required for use with both the Trimedyne and obstruction from other causes, as has been the Mini-Flex instruments because of the shown by Shure, Gregoratos et al'7 in their fragility of the fiberoptic and of the inflatable studies on dogs and humans. These inves- balloon on the distal end. We have used a size tigators performed in the lungs what Harken 11 French Datascope balloon introducer for and Glidden3 performed in the heart. Their inserting the Trimedyne instrument in several technique may offer special advantages in patients, which caused excessive bleeding. clarifying pulmonary hypertension and recur- This could be prevented by using an introduc- rent embolism. tion device equipped with a membrane or

Fig. 12 Angioscopic view of the orifice of a femoral artery with superimposed cross hairs and reffrence lines.

lbxs Heart Institute Joumll Angiogmphy to Angiosceopy 287 diaphragm to prevent back-bleeding. The either up toward the heart or down toward the device should, in addition, be equipped with peripheral artery under study. a side arm to permit flushing around the The coronary artery, however, being shorter angioscope itself. Such devices are not as yet and more tortuous, presents a hazard of perfo- available in the range of sizes needed to ration that entails much more serious conse- accommodate the various sizes ofangioscopes. quences than does the perforation of the Angioscopes should be made available in peripheral vessels. Thus, if angioscopy is to sizes suitable for use in iliac, femoral, renal, become as useful a technique in coronary and coronary arteries. Drs. Inoue and Kuwaki applications as in the peripheral arteries, much use a Sumitomo Angioscope in the following improvement in flexibility of the fiberoptic sizes: French #5 (cardiac), #7, #8, #9, and is required. #14, as shown in Figure 5. For intracar- In summary, fiberoptics should have certain diac angioscopy in dogs, they use a balloon characteristics, and the following procedures equipped model. The angioscope should be should be used with them: provided with a sufficiently inflatable balloon (1) The first 4 to 5 cm to be inserted into at the distal end for both intracardiac and the vessel should be more flexible pulmonary visualization. than the rest and should curve A flexible fiberoptic should be used in order smoothly and gently so as to follow to negotiate the passage from the catheter into the tortuous routes with a minimum the arteries in coronary angioscopy, and to of friction; allow for bending and curving during manipu- (2) the distal end of the guiding catheter lation without breakage of fibers. The distal should not narrow excessively in end should have more flexibility in the last 4 order to facilitate the advance of the to 5 cm than is provided by the instruments angioscope; and currently available in the United States. Using (3) appropriate materials must be the American Edwards Laboratories Mini- selected for composition of the Flex Angioscope, the orifices of the coronary catheter in order to minimize friction. arteries of two patients were inspected follow- The focal length of the optical sys- ing angioplasty. In the first, the coronary tem should be optimal for the distance to the orifice was clearly imaged. In the second, vessel wall, which varies depending upon the however, the advancement of the angioscope area being visualized and the curvatures was prevented by excessive angulation of the encountered. guiding catheter and by excessive rigidity of Reference points are needed in order to the fiberoptic. know exactly how much of the angioscope has It is important not only to see the orifices of been inserted. Markers are used to indicate the vessels, but to see beyond them and into the length in centimeters along the instrument. vessel. Grundfest19 compared angiography Such markers are now provided only on the and angioscopy by an apt analogy . . . "looking Trimedyne Optiscope. at an angiogram is like reading a road map, The optical system should contain refer- while viewing through an angioscope is like ence points such as cross hairs with milli- driving through a tunnel with headlights meter subdivisions indicated across the turned on." To live up to this description, the visual field. These reference points will bring angioscope must be capable of being passed about the angioscope's best potential and easily beyond the orifice and into the lumen utilize the full advantage of the three-dimen- of the artery; and this can be done readily sional view provided. in the peripheral, iliofemoral, and pul- Figure 12 shows an angioscopic view of the monary arteries. orifice of a femoral artery with superimposed Figure 11 shows two different routes of reference lines. Such markings, in addition to catheterization - one via the arm and the the centimeter markings along the length of other via the leg - which we have followed the angioscope, would make possible an exact in our studies of the peripheral arteries. In description of the locations of lesions, such as catheterization via the leg, we can advance is required in preparation for .

288 Angiography to Angioscopy Vol. 13, No. 3, September, 1986 9. Forrester J, Grundfest W, Litvack F, Lee M, DISCUSSION Chaux A, Matloff J, Carrol R, Froan R, Berci G, Morgenstern L. Intraoperative vascular endo- To move from the experimental to the clini- scopy using flexible fiberoptics. Am H Assoc cal stage ofusefulness, discussions are needed Abstracts ofthe 57th Scientific Sessions, Circula- among physicians who perform endoscopic tion Oct 1984; 70(Suppl II):297. procedures. Ideas could be exchanged and 10. Myler RK, Stertzer SH, Millhouse F, Crew J, McMorrow J, Hidalgo B. Intravascular angio- technical details discussed concerning such scopy (IVA) and human peripheral angioplasty. matters as, for instance, the various sizes and Am H Assoc Abstracts of the 57th Scientific types ofconnecting devices and video cameras Sessions, Circulation Oct 1984; 70 (Suppl that may be used. II):265. The formation of a society for angioscopy 11. Inuoe K, Kuwaki K, Takahashi M. Transluminal cardioangioscopy. Am H Assoc Abstracts of the would be beneficial in providing a forum for 56th Scientific Sessions, Circulation Nov 1983; sharing knowledge and skills, and could be 69(Suppl Hl):5. used to demonstrate techniques with animal 12. Inuoe K, Kuwaki K, Takahashi M. In vivo subjects. Such a society might serve as a transluminal angioscopy. Am H Assoc Abstracts training center where instrument manufactur- of the 57th Scientific Sessions, Circulation Oct 1984; 70 (Suppl II):322. ers could offer advice, and practitioners could 13. Lee G, Ikeda RM, Dwyer RM, Hussein H, acquire technical dexterity and familiarize Dietrich P, Mason DT. Feasibility of intravascu- themselves with the capabilities and sen- lar laser irradiation for in vivo visualization and sitivities of various instruments. therapy of cardiocirculatory diseases. Am Heart J 1982; 103:1076-1077. 14. Spears JR, Serur J, Shropshire D, Paulin S. REFERENCES Fluorescence of experimental atheromatous plaques with hematoporphyrin derivative. J Clin 1. Rhea L, Walker IC, Cutler EC. The surgical Invest 1983; 71:395-399. treatment of mitral stenosis: Experimental and 15. Cortis BS, Harris DM, Principe J. Angioscopy of clinical studies. Arch Surg 1924; 9:689-690. hematoporphyrin derivative in experimental 2. Allen DS, Graham EA. Intracardiac surgery: A atherosclerosis. Laser Institute of America new method. Preliminary report. JAMA 1922; ICALEO proceedings 1984; 43:128-130. 79:1028-1030. 16. Forrester J, Litvak F, Grundfest W, Foran R, Lee 3. Harken DE, Glidden EM. Experiments in intracar- M, Fishbein M, Berci G, Meerbaum S, Corday diac surgery. J Thorac Surg 1943; 12:566-572. E. Combined intravascular angioscopic visuali- 4. Greenstone SM, Shore JM, Heringman EC, zation and laser ablation of vascular atheroma Massell TB. Arterial endoscopy (arterioscopy). documented by angiography.JACC 1984; 3:490. Arch Surg 1966; 93:811-813. 17. Shure D, Gregoratos G, Moser KM. Angioscopy 5. Gamble WJ, Innis RE. Experimental intracardiac is useful in the evaluation of chronic pulmonary visualization. N Engl J Med 1967; 276:1397- arterial obstruction. Am H Assoc Abstracts ofthe 1403. 57th Scientific Sessions, Circulation Oct 1984; 6. Moser KM, Shure D, Harrell JH, Tulumello J. 70(Suppl II): 1982. Angioscopic visualization of pulmonary emboli. 18. Ledor K, Ferris EJ, Benavi D, Baker ML, Chest 1980; 77:198-201. Robbins, MB. Percutaneous angioscopy: Meth- 7. Spears JR, Marais HJ, Serur J, Pbmerantzeff 0, odological considerations. SPIE Proceedings of Geyer RP, Sipzener RS, Weintraub R, Thurer R, The International Society for Optical Engineer- Paulen S, Gerstin R, Grossman W. In vivo ing, Aug 1984; 494:54-55. coronary angioscopy. J Am Coll Cardiol 1983; 19. Grundfest WS. Angioscopy lets physicians see 1:1311- 1314. minute structures in blood vessels. Am Coll Surg 8. Cortis BS, Hussein H, Khandekar CS, Principe 70th Annual Clinical Congress, Oct 1984. J, Tkaczuk RN. Angioscopy in vivo. Cathet Cardiovasc Diagn 1984; 10:493-500.

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