J AM COLL CARDIOL 1311 1983.1(5) 1311-4 In Vivo Coronary Angioscopy J. RICHARD SPEARS, MD, FACC , H. JOHN MARAIS, MD, JUAN SERUR, MD, OLEG POMERANTZEFF, ° Eng, ROBERT P. GEYER , PhD, ROBERT S. SIPZENER, MD, RONALD WEINTRAUB, MD, FACC, ROBERT THURER, MD, FACC, SVEN PAULIN, MD, RICHARD GERSTIN, BS, WILLIAM GROSSMAN, MD, FACC Boston. Massachusetts The feasibility of in vivocoronary angioscopywas tested catheterization technique and in patients during open utilizing a 1.8 mm angioscope in vesselswhere blood had heart surgery. The results demonstrate the feasibility been replaced by optically clear liquids, including a new and potential clinical usefulness of direct visualization perfluorocarbon emulsion. After trials in postmortem of intravascular anatomy and disease, analogous to en• canine and human coronary arteries, in vivo intralum• doscopy of other organ systems. inal visualization was accomplished in the dog with a At present, the primary diagnostic method for evaluating technique , progressing from in vitro studies of postmortem coronary anatomy in humans beings is selective coronary hearts to in vivo studies of canine and human coronary angiography. Although this method delineates the coronary arteries. lumen with reasonable accuracy , it allows recognition of Methods pathologic changes principally by identifying filling defects. Description of angioscope. The prototype Olympus ul• Direct visualization of the internal surface of coronary ar• trathin fiberscope used in this study has an external diameter teries would permit not only precise determination of coro• of 1.8 mm and consists of two separate fiberoptic bundles . nary cross-sectional area, but also identification of different One bundle transmits light from an external source through types of vascular disease (for example, thrombus versus the fiberscope into the vessel being examined and the second atheroma) . The major barriers to in vivo visualization of bundle, the image guide, transmits the reflected image back coronary arteries in the past include the opacity of blood to to an adjustable eyepiece. To reduce the outer diameter of visible light and the large size of commercially available this prototype unit to 1.8 mm, the angulation system and fiberoptic scopes relative to coronary artery dimensions (l,2). channels usually provided in endoscopes were not included . The recent development of a high resolution 1.8 mm fiber• Illumination was provided by an Olympus ILK-3 150 watt optic scope, as well as a translucent perfluorocarbon emul• halogen light source. Photography was accomplished by sion blood substitute, has made prolonged in vivo visual• using a special endoscopic camera adapter that was attached ization of the coronary arteries possible. In this report, we to the eyepiece of the endoscope and then fitted to the OM• describe our initial studies during the development of this 2 camera body. The standard ground glass focusing screen was replaced by a special Fresnel lens focusing screen de• signed exclusively for endoscopy . With this photographi c From the Charles A. Dana Research Institute and Harvard-Thorndike system, we were able to perform the endoscopic procedure Laboratory of Beth Israel Hospital. Department of Medicine. Cardiovas• cular Division, and the Radiology Research Center of the Department of through the viewfinder of the 35 mm camera, taking pictures Radiology. Beth Israel Hospital and Harvard Medical School. Boston. whenever appropriate. Massachusetts. This work was supported in part by Young Investigatorship Description of perfluorocarbon emulsion. A new Research Award HL2738-02 from the National Heart. Lung, and Blood Institute. Nauonal Institutes of Health, Bethesda. Maryland. Manuscript translucent perfluorocarbon emulsion blood substitute has received September 21. 1982; revised manuscnpt received December 7. recently been produced by one of us (R.P.G.). Perfluoro• 1982; accepted December 10. 1982 carbon-containing blood replacement preparations can pro• Address for reprints: J. Richard Spears , MD. Department of Medicine, Cardiovascu lar Division . Beth Israel Hospital. 330 Brookline Avenue. vide both oxygen transport and maintenance of oncotic pres• Boston, Massachusetts 022 I5. sure (3-5). These compounds must be emulsified, but the ©1983 by the American College of Cardiol ogy 0735-1097/83/0501311 -4$03 .00 1312 J AM COLL CARDIOL SPEARS ET AL 1983.1(5) 1311-4 resulting emulsions are usually fairly turbid. This turbidity graft surgery, angioscopy was performed after completion would interfere with intravascular visualization by means of the distal anastomosis of the saphenous vein graft to the of fiberoptics; therefore, it is necessary to utilize prepara• left anterior descending coronary artery. Through a side tions that are as low in turbidity as possible. By means of branch of the vein graft, the angioscope was advanced across sonication using suitable emulsifying agents and perfluo• the distal anastomosis and into the native coronary artery. rocarbons, the translucent perfluorocarbon-containing blood In three additional patients, the angioscope was advanced replacement preparation was made. As in previous studies, anterograde into the left anterior descending coronary artery electrolytes and an oncotic agent such as hydroxyethyl starch directly through the arteriotomy. Intraluminal visualization were added. The completed preparation was sterilized by was achieved in each patient with the aid of the translucent filtration and equilibrated with a mixture of 95% oxygen cardioplegic solution normally used to perfuse the vein grafts and 5% carbon dioxide, and the pH was adjusted to 7.45. and coronary arteries. Postmortem studies. Studies were initially conducted on postmortem canine and human hearts from which blood Results had been washed out with normal saline solution. Structures Postmortem canine studies. Initial development of the within the left ventricle were viewed with the fiberscope angioscopic technique involved studies in postmortem ca• which had been passed retrograde across the aortic valve. nine hearts in which details of light source and intensity, An 8 French Cordis sheath was used to gain access to the photographic technique and catheter manipulation could be left main coronary artery. The vessel was perfused at phys• investigated in a totally controlled setting. Figures 1 and 2 iologic pressures with either saline solution or the perfluo• illustrate the detail and photographic quality of images of rocarbon emulsion by way of the sidearm of the sheath. The the mitral valve commissure (Fig. 1) and papillary muscles angioscope was then passed through the rubber diaphragm with chordae (Fig. 2) obtained in the postmortem saline• of the Cordis sheath into the left coronary artery orifice. filled heart. The black spots in these and the other figures Selective angioscopy of the proximal segments of the cir• represent broken optical fibers that were not transmitting cumflex and anterior descending coronary arteries was then the reflected image back to the observer and external camera. performed. Figure 3 shows the lumen of the left anterior descending In vivo canine studies. Adult mongrel dogs weighing artery (viewed from the aortic orifice of the left coronary 20 to 25 kg were anesthetized with morphine sulfate and artery) in a postmortem canine heart using similar techniques. chloralose, intubated and then ventilated with a Harvard In vivo canine studies. After successfully defining the respiratory pump. Cutdown procedures were performed over technical factors necessary to obtain photographic images both carotid arteries. A thoracotomy was performed over under ideal static conditions (Fig. lA, B and C), we pro• the left lateral chest and the heart was suspended in a peri• ceeded to in vivo studies of the normal canine coronary cardial cradle. A 7 French NIH cathether was placed in the vasculature using oxygenated Ringer's lactate solution and descending aorta for measurement of arterial pressure. A perfluorocarbon solution. Figures ID and IE show the in• 21 gauge angiocatheter was inserted into a distal branch of ternal (lumen) surface of the left coronary artery in anes• the left anterior descending coronary artery. Arterial and thetized dogs; these photographs were taken through the intracoronary pressures were measured with Statham P23D6 ultrathin angioscope that had been advanced by a guiding strain gauges and recorded on an Electronics for Medicine catheter into the ostium of the left coronary artery. The ostia multichannel photographic recorder. of arterial branches of the left coronary artery are clearly A 10 French guiding catheter was constructed to facilitate visible. entrance of the fiberscope into the left main coronary artery. Clinical studies. After completion of the in vivo canine After insertion into the carotid artery, the tip of the guiding studies, we studied four patients during the course of coro• catheter was advanced to the left main coronary artery under nary artery bypass graft surgery. Figure 1F shows an ath• fluoroscopy. Ifdistal coronary artery pressure decreased as erosclerotic plaque within the lumen of the left anterior a result of ostial obstruction by the guiding catheter, per• descending artery in one of these patients, after the ultrathin fusion of the left coronary artery could be achieved by angioscope was passed into the artery by way of a side autotransfusion through a connection to the proximal end branch of the saphenous vein graft. The plaque appears of the NIH catheter.