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Endoscopy of the Heart
Endoscopy of the Heart ALLAN ELLIA BLOOMBERG, M.D., F.A.C.S.* ELLIOTT S. HURWITT, M.D., F.A.C.S.**
THE possibility of visualizing the interior of the cardiac chambers by endoscopic instrumentation in the intact heart without interruption of blood flow has intrigued many investigators. This could provide invaluable information concerning the anatomy of congenital and acquired intracardiac lesions. The writings of many recent authors stress the need for methods of direct visualization to supplement the data derived from angiocardiography, cardiac catheterization and palpation. The current monumental advances in open intracardiac surgery, made possible by extracorporeal oxygenators and hypothermia, may stimulate renewed interest in cardiac endoscopy as an ancillary diagnostic tool. The problems unique to cardiac endoscopy, as contrasted with all other endoscopic fields, are the following: the chambers of the heart are filled with an opaque, viscid fluid; interruption of blood flow can only be momentary; the production of arrhythmias must be avoided; and in the normal experimental animal the motion of the valve leaflets and their attachment is so rapid that sustained inspection is not possible. The methods employed to overcome these problems have included: (1) dis':' placement of the blood by bringing the lens system into direct contact with the structure to be visualized; (2) a larger volume displacement of blood by inserting a plastic balloon filled with clear fluid between the lens system and the object; (3) displacement of blood by clear fluid under pressure; and (4) direct transillumination. HISTORICAL DEVELOPMENT
Drs. Lawrence Rhea and I. C. Walker designed a cardioscope in 1913. A picture of their instrument was reproduced by Cutler, Levine and Beck in 1924.1 Cutler says: "The fact that the lens is somewhat inset made it impossible to have intimate contact between the lens and the object, which perhaps accounts for their failure to secure vision." The From the Surgical Division, Montefiore Hospital, New York, N. Y. Montefiore Hospital; Assistant Professor of Clinical Surgery, Albert Einstein CoUege of Medicine . •• Chief of the Surgical Division, Montejiore Hospital; Clinical Professor of Surgery, CoUege of Physicians and Surgeons, Columbia University.
* Associate Attending Surgeon,
1337
1338
Allan Ellia Bloomberg, Elliott S. Hurwitt
Fig. 363. The Rhea and Walker cardioscope, 1913. (Cutler, E. C. et aI., Arch. Burg., Vol. 9. By permission of the American Medical Association).
instrument consisted of a tube carrying in a sheath an electric light and also a small knife which was constructed for the purpose of cutting the valves of the heart (Fig. 363). In 1922, Allen and Graham reported an instrument with which they were able to examine the chambers of the heart, without haste, while normal or near normal flow of blood was taking place. 2 Indeed, they were able to visualize the interior of the heart for as long as 20 minutes in the anesthetized dog. They described their cardioscope as a metal tube, one end of which was closed by a plano convex lens. The plane surface of the lens was within, and the convex surface was of such a curvature that it might be applied snugly to the walls of the heart cavity. A small electric light bulb fitted on a carrier was placed against the plane surface of the lens. The valve leaflets were visualized by holding the cardioscope so that
Endoscopy of the Heart
1339
Fig. 364. The Allen and Graham cardioscope, 1922. (Allen, D. S. and Graham, E. A" J.A.M.A., Vol. 79. By permission of the American Medical Association).
the leaflets came into contact with the lens during systole. A knife to cut the valves was carried alongside the tube of the cardioscope. The blade of the knife was at a right angle to the handle and the cutting edge faced the lens. The whole of the blade rested in a groove cut across the center of the lens (Fig. 364). Cutler combined the Allen-Graham cardioscope with his valvulotome to produce a cardioscopic valvulotome. I • 3 The general plan of the instrument was the same, except that a right angled offset from the handle removed the eyepiece to a safe distance from the sterile field of operation (Fig. 365). In 1926 he stated that he had used the instrument successfully in dogs. He stated further, however, that he could never convince himself of the benefit of such visualization. Keith and Wappler designed an instrument which utilized a glass displacement chamber placed over a thoracoscope with a right angle lens. It brought into the field of vision those structures in contact with the glass displacement chamber (Fig. 366). The instrument also had a fulgurating point in contact with the glass displacement chamber. Aware of the inherent difficulties in small field contact visualization, Harken and Glidden4 in 1943 described attempts to enlarge the field of vision by placing a clear plastic balloon over a light-bearing thoracoscope (Fig. 367). The balloon was inflated with 8 to 15 cc. of saline after being inserted into the atrial appendage in a collapsed state. So distended, the balloon came into intimate contact with various structures. The periods of balloon distention represent temporary circulatory obstruction and it was necessary to decompress the balloon and allow a circulatory recovery period of 10 to 15 seconds between each observation period of 20 to 30 seconds. Brock put to clinical use a cardioscope designed in accordance with the instrument of Allen and Graham. 6 In approaching the problem of direct valvulotomy for pulmonic valvular stenosis, Brock recorded observations on the pulmonic valves of patients through the cardioscope
Allan Ellia Bloomberg, Elliott S. Hurwitt
Fig. 365. The Cutler cardioscope, 1926. (Cutler, E. C., Arch. Surg., Vol. 12. By permission of the American Medical Association).
Fig. 366. The Keith and Wappler cardioscope, 1942. (Harken, D. E. and Glidden, E. M., J. Thoracic Surg., Vol. 12. By permission of C. V. Mosby Co.).
Endoscopy of the Heart
1341
Fig. 367. The Harken and Glidden plastic balloons and cardioscope, 1943. (Harken, D. E. and Glidden, E. M.,:,J. Thoracic Surg., Vol. 12. By permission of C. V. Mosby Co.).
introduced into the left main pulmonary artery. The constant movement of the valveeusps constituted a major limitation to this technique. AIthough_:he considered passing the cardioscope, armed with a valvulotome, into the right ventricle, clinical application of this maneuver in the surgical correction of pulmonic stenosis was apparently not attempted, in view of the results with the simpler and less hazardous "blind" instrumental valvulotomy. ): ,In the discussion of a paper presented by Bailey and co-workers in April 1950, Bloomberg described a method whereby a stream of clear fluid injected under pressure cleared the blood and allowed visualization of a relatively large field inside the heart. 6 Even with this relatively large area of vision the valves moved so rapidly that good visualization was impossible unless the valve was caught and held by a hook attached to the end of the cardioscope. When surgical stenosis of the tricuspid valve was produced by suture, the relative immobilization of the valve lent itself more readily to cutting which was accomplished by means of a valvulotome within the instrument (Fig. 368). With the McCrae Endoscopic Camera it was possible to take photographs of the inside of the intact dog heart. Good visualization of the right side of the heart was obtained without difficulty because of the low pressure system. However, on the left side of the heart the pressure required to clear the blood for visualization was so great that an inordinate amount of fluid was necessary and the animal hearts were unable to tolerate the strain.
Allan Ellia Bloomberg, Elliott S. Hurwitt
Fig. 368. The Bloomberg cardioscope, 1950.
A contact lens type of cardioscope was described by Gordon Murray. 7 He passed the instrument into the heart through a cannula guarded by a valve (Fig. 369). Butterworth reported a cardioscope which retained the contact vision principle but utilized the unique light-transmitting properties of solid perspex (methyl methacrylate).8 He claimed various advantages over previous types of cardioscopes: (1) the entire instrument, aside from the operating knife, is f0rmed from solid perspex of uniform refraction index;
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D Fig. 369. The Murray cardioscope, 1950. (Murray, G., Angiology, Vol. 1. By permission of Williams & Wilkins Co.).
Endoscopy of the Heart
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Fig. 370. The Butterworth cardioscope, 1951. (Butterworth, R. F., J. Thoracic Surg., Vol. 22. By permission of C. V. Mosby Co.).
(2) the visual field extends to the extreme edge of the instrument without obstruction by light source or metal casing; (3) there are no lenses to become misted over or produce aberration; (4) the light source is outside the instrument, and may be replaced if necessary with the instrument in situ; (5) the tips may be fashioned to any desired plane surface or angle without distortion or loss; (6) the instrument is readily sterilized (Fig. 370). The cardioscope designed by Bolton and his colleagues also utilized a plastic. 9 By making the light carrier lucite with a large bore, he was able
Fig. 371. The Bolton cardioscope, 1954. (Bolton et aI., J. Thoracic Surg., Vol. 27. By permission of C. V. Mosby Co.).
13#
Allan Ellia Bloomberg, Elliott S. Hurwitt
to obviate the need for an additional source of light. The instrument has various types of knives which may be inserted alongside the shaft (Fig. 371). In the animal, Bolton has been able to visualize all of the chambers and all of the valves. He states that he has found this of value in estimating the size and location of interatrial septal defects, and that he has obtained satisfactory photographs in about 30 per cent of his attempts. Hurwitt attempted visualization of the interior of the heart by placing a source of light of considerable magnitude within the cardiac· chambers without utilizing a lens system. 10 He was unable to visualize the interior of the heart, but the transillumination of the cardiac muscle produced by the interior light gave a clear-cut picture of the coronary arteries, a fact which may be of considerable value when coronary artery surgery, with its need for differentiating normal from diseased coronaries, becomes an accomplished fact. COMMENT
The inadequacies of these instruments are attested by the failure of their designers to pursue clinical application. Open heart surgery, with direct visualization, is obviously better than any endoscopic approach. The open heart surgery which we have seen has been attended in some cases by an obscuring film of blood, which, in certain instances, has led to failure to detect some of the interventricular defects. A blood-clearing stream of clear fluid, combined with a lens system small enough to maneuver between the intricacies of the pectinate muscles, may be of some help in finding ventricular septal defects. Intracardiac transillumination provides a promising tool in the development of surgery of the coronary arteries. REFERENCES 1. Cutler, E. C., Levine, S. A. and Beck, C. S.: Surgical Treatment of Mitral Steno-
sis: Experimental and Clinical Studies. Arch. Surg. 9: 689, 1924. 2. Allen, D. S. and Graham, E. A.: Intracardiac Surgery-A New Method. J.A.M.A. 79: 1028, 1922. 3. Cutler, E. C.: Surgical Aspect of Mitral Stenosis. Arch. Surg. 12: 212,1926. 4. Harken, D. E. and Glidden, E. M.: Experiments in Intracardiac Surgery. II. Intracardiac Visualization. J. Thoracic Surg. 12: 566, 1943. 5. Brock, R. C.: Pulmonary Valvulotomy for Relief of Congenital Pulmonary Stenosis. Brit. M. J. 1: 1121, 1948. 6. Bailey, C. P., Glover, R. P., O'Neill, T. J. E. and Ramirez, H. P. R.: Experiences with the Experimental Surgical Relief of Aortic Stenosis. J. Thoracic Surg. 20: 516, 1950. 7. Murray, Gordon: A Cardioscope. Angiology 1: 334,1950. 8. Butterworth, R. F.: A New Operating Cardioscope. J. Thoracic Surg. 22: 319, 1951. 9. Bolton, H. E., Bailey, C. P., Costas-Durieux, J. and Gemeinhardt, W.: Cl.rdio3copy, Simple and Practical. J. Thoracic Surg. 27: 323, 1954. 10. Hurwitt, E. S.: Unpublished material. Montefiore Hospital Gun Hill Road New York, N. Y.
THE possibility of visualizing the interior of the cardiac chambers by endoscopic instrumentation in the intact heart without interruption of blood flow has intrigued many investigators. This could provide invaluable information concerning the anatomy of congenital and acquired intracardiac lesions. The writings of many recent authors stress the need for methods of direct visualization to supplement the data derived from angiocardiography, cardiac catheterization and palpation. The current monumental advances in open intracardiac surgery, made possible by extracorporeal oxygenators and hypothermia, may stimulate renewed interest in cardiac endoscopy as an ancillary diagnostic tool. The problems unique to cardiac endoscopy, as contrasted with all other endoscopic fields, are the following: the chambers of the heart are filled with an opaque, viscid fluid; interruption of blood flow can only be momentary; the production of arrhythmias must be avoided; and in the normal experimental animal the motion of the valve leaflets and their attachment is so rapid that sustained inspection is not possible. The methods employed to overcome these problems have included: (1) dis':' placement of the blood by bringing the lens system into direct contact with the structure to be visualized; (2) a larger volume displacement of blood by inserting a plastic balloon filled with clear fluid between the lens system and the object; (3) displacement of blood by clear fluid under pressure; and (4) direct transillumination. HISTORICAL DEVELOPMENT
Drs. Lawrence Rhea and I. C. Walker designed a cardioscope in 1913. A picture of their instrument was reproduced by Cutler, Levine and Beck in 1924.1 Cutler says: "The fact that the lens is somewhat inset made it impossible to have intimate contact between the lens and the object, which perhaps accounts for their failure to secure vision." The From the Surgical Division, Montefiore Hospital, New York, N. Y. Montefiore Hospital; Assistant Professor of Clinical Surgery, Albert Einstein CoUege of Medicine . •• Chief of the Surgical Division, Montejiore Hospital; Clinical Professor of Surgery, CoUege of Physicians and Surgeons, Columbia University.
* Associate Attending Surgeon,
1337
1338
Allan Ellia Bloomberg, Elliott S. Hurwitt
Fig. 363. The Rhea and Walker cardioscope, 1913. (Cutler, E. C. et aI., Arch. Burg., Vol. 9. By permission of the American Medical Association).
instrument consisted of a tube carrying in a sheath an electric light and also a small knife which was constructed for the purpose of cutting the valves of the heart (Fig. 363). In 1922, Allen and Graham reported an instrument with which they were able to examine the chambers of the heart, without haste, while normal or near normal flow of blood was taking place. 2 Indeed, they were able to visualize the interior of the heart for as long as 20 minutes in the anesthetized dog. They described their cardioscope as a metal tube, one end of which was closed by a plano convex lens. The plane surface of the lens was within, and the convex surface was of such a curvature that it might be applied snugly to the walls of the heart cavity. A small electric light bulb fitted on a carrier was placed against the plane surface of the lens. The valve leaflets were visualized by holding the cardioscope so that
Endoscopy of the Heart
1339
Fig. 364. The Allen and Graham cardioscope, 1922. (Allen, D. S. and Graham, E. A" J.A.M.A., Vol. 79. By permission of the American Medical Association).
the leaflets came into contact with the lens during systole. A knife to cut the valves was carried alongside the tube of the cardioscope. The blade of the knife was at a right angle to the handle and the cutting edge faced the lens. The whole of the blade rested in a groove cut across the center of the lens (Fig. 364). Cutler combined the Allen-Graham cardioscope with his valvulotome to produce a cardioscopic valvulotome. I • 3 The general plan of the instrument was the same, except that a right angled offset from the handle removed the eyepiece to a safe distance from the sterile field of operation (Fig. 365). In 1926 he stated that he had used the instrument successfully in dogs. He stated further, however, that he could never convince himself of the benefit of such visualization. Keith and Wappler designed an instrument which utilized a glass displacement chamber placed over a thoracoscope with a right angle lens. It brought into the field of vision those structures in contact with the glass displacement chamber (Fig. 366). The instrument also had a fulgurating point in contact with the glass displacement chamber. Aware of the inherent difficulties in small field contact visualization, Harken and Glidden4 in 1943 described attempts to enlarge the field of vision by placing a clear plastic balloon over a light-bearing thoracoscope (Fig. 367). The balloon was inflated with 8 to 15 cc. of saline after being inserted into the atrial appendage in a collapsed state. So distended, the balloon came into intimate contact with various structures. The periods of balloon distention represent temporary circulatory obstruction and it was necessary to decompress the balloon and allow a circulatory recovery period of 10 to 15 seconds between each observation period of 20 to 30 seconds. Brock put to clinical use a cardioscope designed in accordance with the instrument of Allen and Graham. 6 In approaching the problem of direct valvulotomy for pulmonic valvular stenosis, Brock recorded observations on the pulmonic valves of patients through the cardioscope
Allan Ellia Bloomberg, Elliott S. Hurwitt
Fig. 365. The Cutler cardioscope, 1926. (Cutler, E. C., Arch. Surg., Vol. 12. By permission of the American Medical Association).
Fig. 366. The Keith and Wappler cardioscope, 1942. (Harken, D. E. and Glidden, E. M., J. Thoracic Surg., Vol. 12. By permission of C. V. Mosby Co.).
Endoscopy of the Heart
1341
Fig. 367. The Harken and Glidden plastic balloons and cardioscope, 1943. (Harken, D. E. and Glidden, E. M.,:,J. Thoracic Surg., Vol. 12. By permission of C. V. Mosby Co.).
introduced into the left main pulmonary artery. The constant movement of the valveeusps constituted a major limitation to this technique. AIthough_:he considered passing the cardioscope, armed with a valvulotome, into the right ventricle, clinical application of this maneuver in the surgical correction of pulmonic stenosis was apparently not attempted, in view of the results with the simpler and less hazardous "blind" instrumental valvulotomy. ): ,In the discussion of a paper presented by Bailey and co-workers in April 1950, Bloomberg described a method whereby a stream of clear fluid injected under pressure cleared the blood and allowed visualization of a relatively large field inside the heart. 6 Even with this relatively large area of vision the valves moved so rapidly that good visualization was impossible unless the valve was caught and held by a hook attached to the end of the cardioscope. When surgical stenosis of the tricuspid valve was produced by suture, the relative immobilization of the valve lent itself more readily to cutting which was accomplished by means of a valvulotome within the instrument (Fig. 368). With the McCrae Endoscopic Camera it was possible to take photographs of the inside of the intact dog heart. Good visualization of the right side of the heart was obtained without difficulty because of the low pressure system. However, on the left side of the heart the pressure required to clear the blood for visualization was so great that an inordinate amount of fluid was necessary and the animal hearts were unable to tolerate the strain.
Allan Ellia Bloomberg, Elliott S. Hurwitt
Fig. 368. The Bloomberg cardioscope, 1950.
A contact lens type of cardioscope was described by Gordon Murray. 7 He passed the instrument into the heart through a cannula guarded by a valve (Fig. 369). Butterworth reported a cardioscope which retained the contact vision principle but utilized the unique light-transmitting properties of solid perspex (methyl methacrylate).8 He claimed various advantages over previous types of cardioscopes: (1) the entire instrument, aside from the operating knife, is f0rmed from solid perspex of uniform refraction index;
CARDIOSCOPE A
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... 4·r
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Knife blades
Illlllll/l~
Needle
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rlllllllllllllllllllllllllll II.
D Fig. 369. The Murray cardioscope, 1950. (Murray, G., Angiology, Vol. 1. By permission of Williams & Wilkins Co.).
Endoscopy of the Heart
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Fig. 370. The Butterworth cardioscope, 1951. (Butterworth, R. F., J. Thoracic Surg., Vol. 22. By permission of C. V. Mosby Co.).
(2) the visual field extends to the extreme edge of the instrument without obstruction by light source or metal casing; (3) there are no lenses to become misted over or produce aberration; (4) the light source is outside the instrument, and may be replaced if necessary with the instrument in situ; (5) the tips may be fashioned to any desired plane surface or angle without distortion or loss; (6) the instrument is readily sterilized (Fig. 370). The cardioscope designed by Bolton and his colleagues also utilized a plastic. 9 By making the light carrier lucite with a large bore, he was able
Fig. 371. The Bolton cardioscope, 1954. (Bolton et aI., J. Thoracic Surg., Vol. 27. By permission of C. V. Mosby Co.).
13#
Allan Ellia Bloomberg, Elliott S. Hurwitt
to obviate the need for an additional source of light. The instrument has various types of knives which may be inserted alongside the shaft (Fig. 371). In the animal, Bolton has been able to visualize all of the chambers and all of the valves. He states that he has found this of value in estimating the size and location of interatrial septal defects, and that he has obtained satisfactory photographs in about 30 per cent of his attempts. Hurwitt attempted visualization of the interior of the heart by placing a source of light of considerable magnitude within the cardiac· chambers without utilizing a lens system. 10 He was unable to visualize the interior of the heart, but the transillumination of the cardiac muscle produced by the interior light gave a clear-cut picture of the coronary arteries, a fact which may be of considerable value when coronary artery surgery, with its need for differentiating normal from diseased coronaries, becomes an accomplished fact. COMMENT
The inadequacies of these instruments are attested by the failure of their designers to pursue clinical application. Open heart surgery, with direct visualization, is obviously better than any endoscopic approach. The open heart surgery which we have seen has been attended in some cases by an obscuring film of blood, which, in certain instances, has led to failure to detect some of the interventricular defects. A blood-clearing stream of clear fluid, combined with a lens system small enough to maneuver between the intricacies of the pectinate muscles, may be of some help in finding ventricular septal defects. Intracardiac transillumination provides a promising tool in the development of surgery of the coronary arteries. REFERENCES 1. Cutler, E. C., Levine, S. A. and Beck, C. S.: Surgical Treatment of Mitral Steno-
sis: Experimental and Clinical Studies. Arch. Surg. 9: 689, 1924. 2. Allen, D. S. and Graham, E. A.: Intracardiac Surgery-A New Method. J.A.M.A. 79: 1028, 1922. 3. Cutler, E. C.: Surgical Aspect of Mitral Stenosis. Arch. Surg. 12: 212,1926. 4. Harken, D. E. and Glidden, E. M.: Experiments in Intracardiac Surgery. II. Intracardiac Visualization. J. Thoracic Surg. 12: 566, 1943. 5. Brock, R. C.: Pulmonary Valvulotomy for Relief of Congenital Pulmonary Stenosis. Brit. M. J. 1: 1121, 1948. 6. Bailey, C. P., Glover, R. P., O'Neill, T. J. E. and Ramirez, H. P. R.: Experiences with the Experimental Surgical Relief of Aortic Stenosis. J. Thoracic Surg. 20: 516, 1950. 7. Murray, Gordon: A Cardioscope. Angiology 1: 334,1950. 8. Butterworth, R. F.: A New Operating Cardioscope. J. Thoracic Surg. 22: 319, 1951. 9. Bolton, H. E., Bailey, C. P., Costas-Durieux, J. and Gemeinhardt, W.: Cl.rdio3copy, Simple and Practical. J. Thoracic Surg. 27: 323, 1954. 10. Hurwitt, E. S.: Unpublished material. Montefiore Hospital Gun Hill Road New York, N. Y.