33
First Clinical Experiences with a New Angioscopic System for Diagnosing Peripheral Vascular Changes J. Ennker, C. M. Gross, G. Biamino* andR. Hetzer German Heart Institute Berlin * Department of Radiology, Center of Laser Angioplasty, University Hospital Rudolf Virchow, Free University of Berlin, Germany
Conventional angiography allows a global view of regional vascular anatomy but precise information can only be deduced indirectly using contrast medium. The use of the three-dimensional picture of angioscopy, however, allows a direct evaluation of the vascular system. In order to extend our experiences with angioscopy, we employed a new micro-cardio-angioscopic system which consists of four components: a CCD color camera (360 000 pixels); a highly flexible optical probe which can be resterilised (1.4-0.6 mm diameter) incorporating 10600-6000 glass fibers, with a viewing angle of 140°, 70°, and 50° and a focusing system that allows a distance from 2 mm to infinity; a high power light source and an insertion catheter with inflatable balloon. Using a known technique (intermittent blood-flow blockage and continual rinsing with NaCI solution), 36 cases involving 27 patients were examined before and after desobliteration of the femoral artery. In 88 % ofthe cases it was possible to control the result of the intervention by angioscopy. Smaller intimal lips, the thrombotic wall, and intimal ruptures were clearly visible. Quantification ofthe stenoses was also successful in 88% ofthe cases, and in 8 patients the angioscopic findings deviated from the conventional angiogram. In 14% of the cases, angioscopic examination of the recanalisation result showed that thrombolytic therapy was necessary. Angioscopy offers the possibility of qualitative vascular diagnosis. It is a valuable addition to angiography. Key words Angioscopy - Vascular diagnosis - Peripheral vessels - Laser angioplasty
Introduction During recent years new percutaneous revascularisation procedures in angioplasty have spread throughout the world (1, 2, 9, 10, 11, 16). With increasing application, the interest in direct intraluminal imaging of obliterating vascular processes has increased, an the one hand to carry out therapeutic control of angioplastic interventions, an the other hand to complete the Eindings of angiographic examinations.
Erste klinische Erfahrungen mit einem neuen AngioskopieSystem zur Diagnostik peripherer Gefäß -Veränderungen Die konventionelle Angiographie gewährt einen globalen Überblick über die regionale Gefäßanatomie, genaue Information kann jedoch nur indirekt aus der Kontrastgebung geschlossen werden. Das Bild der Angioskopie erlaubt demgegenüber eine direkte Beurteilung des Gefäßsystems. Um unsere Erfahrungen mit der Angioskopie zu erweitern, haben wir ein neues MikroCardio-Angioskopie-System eingesetzt, welches im einzelnen aus folgenden Komponenten besteht: CCD-Farbkamera (360000 Bildpunkte); hochflexible, resterilisierbare optische Sonde (1,4-0,6mm Durchmesser), in denen 10600-6000 Glasfasern inkorporiert sind, wobei der Betrachtungswinkel zwischen 140°, 70° und 50° variiert und ein Fokusabstand von 2 mm bis unendlich ermöglicht wird; Hochleistungslichtquelle und Führungskatheter mit aufblasbarem Ballon. Mittels bekannter Technik (intermittierende Blutflußblokkierung, kontinuierliche Spülung mit NaCI-Lösung) wurden in 36 Fällen und bei 27 Patienten vor und nach Desobliteration die Arteria femoralis untersucht. Mit Hilfe des Angioskops war es möglich, in 88% der Fälle das Ergebnis der Intervention zu kontrollieren. Kleinere Intimalefzen, wandständiger Thrombus und Intimaaufbrüche konnten sicher dargestellt werden. Die Quantifizierung von Stenosen gelang ebenfalls in 88 % der Fälle. Bei 8 Patienten wich der angioskopische Befund vom konventionellen Angiogramm ab. In 14 % der Fälle sahen wir nach angioskopischer Kontrolle des Rekanalisationsergebnisses die Notwendigkeit der Einleitung einer lytischen Therapie. Die Angioskopie bietet die Möglichkeit einer qualitativen Gefäßdiagnostik und stellt eine sinnvolle Zusatzuntersuchung zur Angiographie dar.
Conventional or computer-assisted angiographic examination permits a determination of the extent and quantity of obliterating vascular processes reaching the smallest vascular segments and is still considered a "golden standard" for the documentation of vascular changes (18). Detailed information, however, can only be obtained when contrasts are visible. In 1965, Vollmar published the results of the successful application of intraluminal endoscopical examination in vascular surgery for the first time, whereby initially rigid endoscopes were used with large lumina and restricted
This paper was presented in part at the 20`h Annual Meeting of the German Society for Thoracic and Cardiovascular Surgery, Bonn, February 1991 Thorac. cardiovasc. Surgeon 40 (1992) 33-37 © Georg Thieme Verlag Stuttgart • New York
Received for Publication: August 1, 1991
Downloaded by: Universite Laval. Copyrighted material.
Summary
1. Ennker, C. M. Gross, C. Biamino, and R. Hetzer
Thome. eardiovase. Surgeon 40 (1992)
65° or 140° 50° or 65°
flexibility (17). Further development led to increasingly thinner, more flexible and thus more easily applicable angioscopic systems (14, 15). These technical improvements of fiberoptic systems led to increased application in vascular surgery as well as in the field of interventional cardio-angiology (3, 4, 5, 13, 20). The experiences so far gained seem to indicate that the color image obtained by angioscopic examination allows direct inspection ofthe vascular lumen and reveals information on surface structure and morphology, and precisely limits the site of vascular stenosis (18). After renewed technological advance in the form of a new micro-cardio-angioscopic system (MASY*) it is now important to assess the method's clinical value in peripheral Excimer laser angioplasty.
50' 50'
Method
Technical data of the MASY system CCD Miniature Color Video Camera PAL or NTSC TV system weight: 25g Picture dots: 360000 length,5l.Bmm Driving power: 12 V, 4 W diameter: 17.5mm Minimal illumination: 3 Lux Resolution: horizontal 360 lines, vertical 420 lines Role of closure of shutter: 1II000s Flexible Probes Outer diameter (mm)
1.4 0.96 0.60 expo 0.35 expo
Glass fibers
Length 1m)
o ("m)
0.25-2.0 0.25-2.0 O.BO OBO
View angle
n
3.0-3.510,000 3.0-3.5 9,600 1.0-1.5 5,000 1.0- 1.5 2,000
Illumination Flexible light conductor: length 2.5 m, 0.10 mm High·power light source; 250W Osram halogen lamp, ca. 20000 Lux Insertion Catheter
Type
Length (em)
peripheral coronary
60-100 150
Diameter outside inside
Balloon
FB
yes (6mm) yes (3mm)
F5
1.6mm 1.2mm
~CCD
coior e.men
,
\
1'-(."b1..
ng;o.....
Fig. 1 CGD miniature color video camera with exchangable and sterilisable optical probe.
The MASY system consists ofa CCO miniature color videa camera. a highly nexible. sterilised probe (exchangable), a high-power light source. and an insertion catheter. A 25 g CCD camera with a diameter of 17.5 mm and a length of 52 mm was used. The camera produces 260000 pixels and needs at least a 3 Lux light source. Via a TV adaptor. the camera can be connected to a focusing system (2 mm to infinity) which enables simultaneous enlargement of intravascular structures during an intervention. ifrequired. At present. lWO lypcs of Oexible probe are available for clinical use: 1.4mm outer diameter with 10600 and 0.96mm with 9600 incorporated optical fibers. There are various lense systems altached to the top of the angioscope which allow a viewing of intravascular structures from an angle of 50°. 65°, and 140°. l1Iumination with nearly 20000 Lux is achieved by the application of a high-power light source (250 W Osram halogen lamp) and a highly flexible light-conductor. At the start, employing the traditonallCchnique, the femoral artery was punctured and a F9 lock was placed. The angioscope was inserted using a catheter with the lock system already pOSitioned and was moved to the desired place with the aid of visual control. In order to view the intravascular structures, it is necessary to remove the blood completely. or nearly so, from the vessels. It was therefore, necessary to develop an insertion catheter with an inflatable balloon at the tip. By intermittent blocking of the blood flow with the inflatable balloon and positioning of the angioscope at lhe lOp of the gUiding catheter, and by administering small amounts ofheparinised saline solution for continuous rinsing. it is possible to view intravascular structures directly. The described technique was used in 27 cases before and after desobliteration or the femoral artery and in 36 diagnostic procedures. The images obtained can be stored on tape and/or fixed by means of a color video printer.
Results and Discussion The first clinical experiences showed that in every case we succeeded in presenting angioscopically the segment of the vessel supposed to be viewed. in three cases the angioplasty result could be viewed only partially after laser recanalisation. In spite of sufficient rinsing of the angioscope and the use of an inflated balloon, we did not succeed in keeping the tip of the angioscope free of blood. However, in the majority of cases it was possible to view closed or stenotic vessel areas with only a smalJ amount of rinsing or sometimes without any rinsing, even for a prolonged period of time. Thus the severity of a vascular stenosis could be diagnosed with certainty angioscopically (in 88 %). In 8 cases (12%)the * A. D. Krauth, Hamburg
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34
angiographic findings clearly deviated from the intravascular documentation of the vessel obstruction: evaluation of angiographic findings resulted in a less severe degree of stenosis than was actually present and confirmed by angioscopy, also thrombotic wall coverings remained undetected by angiography. The presentation of the morphology of arteriosclerotically changed vascular areas was possible in aU remaining cases in a technically impressive form. Through the insertion ofthe angioscope after desobliteration of the femoral artery, the results obtained could be viewed directly. Intimal wall lesions with fiaps, wall dissection, and even intimal ruptures could be shown. The vascular wall lesions were unrelated to the interventional procedure performed, however they occurred less often when laser angioplasty alone had been applied. The surface structure of the arteriosclerotic changes (smooth, intact, rough, crater-shaped) and the extent of these could be described reliably and in detail. Especially after interventional procedures, we succeeded in obtaining information on the mobility of newly formed intimal flaps and on thrombotic remnants or additional thrombi in the vascular wall. Dissections after PTA could he recognised by angioscopy in every case. It was impressive to note how occlusions of a mainly thrombotic nature could be diagnosed and differentiated from sclerotic closures. In cases of thrombotic developments in the vascular wall after performance of vascular recanalisation (14 %), we applied local thrombolytic follow-up therapy; however vascular closures mostly showed a heterogenic composition of thrombotic and sclerotic material. Summarising, it can be said that a major advantage of percutaneous angioscopy consists of the possibility of qualifying vascular diagnosis. By direct viewing of the vessels, additional morphological information can be gained about type, components, and progression of the arteriosclerotic vascular changes. One limit of the procedure is that a differentiation between sclerotic plaques was only partially possible as angioscopy is solely a descriptive type of examination. Evaluation ofour investigations shows that the morphologic presentation of the pathologic anatomical findings succeeded in over 90% of cases in a technicaJJy perfect way, so that the pathological findings could be clearly distinguished from normal vascular conditions. This included recognition of the structure of the plaque surface (for example rough, crater-shaped, or smooth) as well as an assessment of mobility within the blood flow. We classified our results into categories with the aid of the already existing angioscopic classifications of findings (18). It remains unclear to what extent angioscopical findings and clinical symptoms can be correlated. There is still a controvery in the literature about whether it is possible to quantify obstructive vascular segments (8, 12, 19). This is partially due to the fact that an angioscopic assessment ofthe severity ofluminal narrowing depends on the exact coaxial positioning ofthe optical probe within the vascular lumen, and on the applied rinsing pressure of the rinsing liquid. On the other hand, information on the extent of stenotic vascular segments must be assembled from a composition of angioscopic images, as very often not the whole of the vascular cross-section can be presented at once. Quantitatively results can be obtained through optical distortions in relation to the view from the far angle of the point of the probe or when the angioscope is applied outside the focal area (18). Analysis of our angios-
Thorae. eardiovase. Surgeon 40 (1992)
35
Fig. 2 View of the MASY camera-catheter ready for use
Fig. 3 Highly flexible angioscope of 0.96 mm outer diameter for use with FS blue insertion catheter.
Fig. 4 Angioscopic system MASY with color TV monitor, camera-steering appliance, high·power light source, and color video printer.
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First Clinical Experiences wilh a New Angioscopie System
Thome. eardiovase. Surgeon 40 (J 992)
J. Ennker, C. M. Gross. G. Biamina, and R. Hetzer
Fig.5 75 %stenosis of lumen of the superficial femoral artery before and after Excimer laser angioplasty. The patient had suffered for several years from peripheral arterial closure (PAC), until his walking ability was limited to a maximum of 150m,
Fig.8 Severe stenosis of the superficial femoral artery in the lower third of the femur. Deviating from this: 50% stenosis of the lumen in the angiogram. Comparing the angioscopic picture with these findings, one notices anearly complete closure of the vessel with only slit·like lumen. The severity of PAC combined with a walking distance reduced to 100m could thus be better correlated than with conventional angiography in this 60·year·old patient.
Fig. 6 Same patient: By means of laser catheterisation and subsequent con· ventional balloon angioplasty, recanafisation of asevere stenosis was achieved. It is clearly visible that, after peripheral transluminal balloon angioplasty (PTA), an intimal dissection took place with "buckle" formation and circumscribed thrombotic layers.
Fig.9 Mainly sclerotic closure before and after Excimer laser recanalisation. Top left a collateral branch is visible.
Fig.7 Same patient: Final results of asuccessful laser angioplastywith subsequent ba!loon·angioplasty of a 70% stenosis of the superficial femoral artery. The blueish border of the angioscopic picture is caused by the blue insertion catheter. The recanalised superficial femoral artery is completely open for blood flow and shows some accumulation of thrombotic wall layers.
copical findings of stenoses revealed that quantification could be achieved and that these findings partially deviated significantly from the angiographic findings (case example 11). This was also observed by other groups (19), for example White et al., who in 67 intraoperative angioscopic examinations of peripheral vessels and 17 bypass grafts could determine a significant difference between angioscopy and angiography in 21 % of the cases. Likewise, in two cases he found stenoses that the angiographic examination had not shown, as well as artefacts in the preoperative angiogram, and remnants of thrombi after thrombembolectomy. In our examination of peripheral vessels. we did not encounter vascular spasm which has often been considered a major complication of angioscopy (6) by other groups. The same can be maintained with regard to induced embolisalion and vascular perforation. We therefore consider the procedure to be particularly safe with a low rate of complications.
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36
First ClinicalExperiences with a NewAngioscopic System
Isner, J., and R. Clark: Laserangioplasty: Unravelling the Gordian Knot. J. Am. Coll. Cardiol. 7 (1986) 705-711 10 Kensey, K., J Nash, C. Abrahams, K. Cake, and C. Zarius: Recanali-
zation of Obstructed Arteries using a Flexible Rotating Tip Catheter. Circulation 74 (1986) II-457 11
12
13
14
15
References
16
1 Bauriedel, G., and B. Höfling: Adjunctive Angioscopy during Percutaneous Atherectomy. European Heart J. 9 (1988) Suppl. A: 132
2 Beck, A., und N. Nako: Angioskopische Kontrolle der perkutanen Gefäßendoprothese. Erfahrungsbericht über ein speziell entwickeltes transmurales Gefäßendoprothesenmodell und dessen angioskopische Kontrolle in situ. Cor. Vas. 3 (1988) 119-125 3 Chaux, A., M. Lee, C. Blanche, R. Kass, T. Shermann, A. Hickey, F. Litvack, W. Grundfest, J. Forrester, and F. Matloff.: Intraoperative CoronaryAngioscopy. J. Cardiovasc. Surg. 92 (1986) 972-976 4 Fleisher, H. L., B. W. Thompson, and T. McGowan: Angioscopically monitored Saphenous Vein Valvulotomy. J. Vasc. Surg. 4 (1986) 360-364 Forrester, J. S., F. Litvack, and W. S. Grundfest: Laser Angioplasty and Cardiovascular Disease. J. Am. Coll. Cardiol. 57 (1986) 990-992 6 Forrester, J S., F. Litvack, W. Grundfest, andA. Hickey: APerspective of Coronary Disease seen through the Arteries of Living Man. Circulation 75 (1987) 505-513 7 Forrester, J., A. Jakubowski, A. Hickey, F. Litvack, and W. Grundfest: Coronary and Peripheral Vascular Angioscopy. In: Vogel, J., and S. King, ed.: Interventional Cardiology: Future Directions. St. Louis-Baltimore-Philadelphia-Toronto, Mosby, 1989, pp 36-53 0 Hombach, V., M. Höher, A. Hannekum, M. Hügel, B. Wutan, H. Höpp, und H. Hirche: Erste klinische Erfahrungen mit der Koronarendoskopie. Dtsch. Med. Wschr. 111 (1986) 1135-1140
17
Lee, G., M. Chan, R. Keda, M. Lee, R. Reis, J. Hick, J. Dukisch, W Baumer, E. Hanna, and D. Mason: Laser Therapy of Coronary Artery Obstruction. Cardiol. Clin. 3 (1985) 93-100 Lee, G., H. J. Garcia, P. Corso, M. Chan, J Ring, A. Pichard, K. Lee, R. Reiss, and D. Mason: Correlation of Coronary Angioscopic to Angiographic Findings in Coronary Artery Disease. Am. J. Cardiol. 58 (1986) 238-241 Seeger, J M., and G. S. Abela: Angioscopy as an Adjunct to Arterial Reconstructive Surgery: A Preliminary Report. J. Vasc. Surg. 5 (1986) 315-320 Tanabe, T., A. Yokota, and S. Sugic: Cardiovascular Fiberoptic Endoscopy: Development and Clinical Application. Surgery 87 (1980) 375-379 Towne, J.: Vascular Endoscopy: Useful Tool or Interesting Toy? Surgery 82 (1977) 415-419 Vallbracht, C., B. Süss, H. Awiszus, L Prignitz, G. Liermann, J. Kollath, H. Landgraf W. Schoop, M. Kaltenbach: Low Speed Rational Angioplasty - Acute Results and Complications in 33 Patients with Chronic Obstruction. European Heart J 9 (1988) (S 1) 333
Vollmar, J., K. Junghanns: Die Arterioskopie. Langenbecks Arch Klin Chir 325 (1969) 1201
18
Wendt, Th.: Neue Einblicke - Angioskopie und Mikroendoskopie. Frankfurt am Main, Theo Hofmann 1990 19 White, G. H., R. A. White, G. E. Kopchok, S. R. Klein, S. E. Wilson: Intraoperative Video Angioscopy compared with Arteriography during Peripheral Vascular Operations. J. Vasc Surg 6 (1987) 488-495 20 White, G. H., R. A. White, G. E. Kopchok: Angioscopic Thromboembolectomy: Preliminary Observations with a Recent Technique. J Vasc Surg 7 (1988) 318-325
Dr. Jürgen Ennker Deutsches Herzzentrum Berlin Augustenburger Platz 1 D-1000 Berlin 65 Germany
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Undoubtedly, the inspection of various vascular sections can be repeated with the aid of angioscopy and does not require a lot of time. In contrast to conventional angiography, neither patient nor investigator is burdened with radiation, nor is the patient exposed to the risk of multiple contrast-fluid applications. Angioscopy, in our opinion and the opinion of other working groups (7), is an important and useful addition to angiography, enhancing qualitative diagnosis. In the Future, especially in the field of coronary artery intervention, the question whether there is a correlation between angioscopic findings and clinical symptoms must be considered and the therapeutic strategy determined accordingly. An attempt to answer this will be our working group's next task.
Thorac. cardiovasc. Surgeon 40 (1992) 37
First Clinical Experiences with a New Angioscopic System for Diagnosing Peripheral Vascular Changes J. Ennker, C. M. Gross, G. Biamino* andR. Hetzer German Heart Institute Berlin * Department of Radiology, Center of Laser Angioplasty, University Hospital Rudolf Virchow, Free University of Berlin, Germany
Conventional angiography allows a global view of regional vascular anatomy but precise information can only be deduced indirectly using contrast medium. The use of the three-dimensional picture of angioscopy, however, allows a direct evaluation of the vascular system. In order to extend our experiences with angioscopy, we employed a new micro-cardio-angioscopic system which consists of four components: a CCD color camera (360 000 pixels); a highly flexible optical probe which can be resterilised (1.4-0.6 mm diameter) incorporating 10600-6000 glass fibers, with a viewing angle of 140°, 70°, and 50° and a focusing system that allows a distance from 2 mm to infinity; a high power light source and an insertion catheter with inflatable balloon. Using a known technique (intermittent blood-flow blockage and continual rinsing with NaCI solution), 36 cases involving 27 patients were examined before and after desobliteration of the femoral artery. In 88 % ofthe cases it was possible to control the result of the intervention by angioscopy. Smaller intimal lips, the thrombotic wall, and intimal ruptures were clearly visible. Quantification ofthe stenoses was also successful in 88% ofthe cases, and in 8 patients the angioscopic findings deviated from the conventional angiogram. In 14% of the cases, angioscopic examination of the recanalisation result showed that thrombolytic therapy was necessary. Angioscopy offers the possibility of qualitative vascular diagnosis. It is a valuable addition to angiography. Key words Angioscopy - Vascular diagnosis - Peripheral vessels - Laser angioplasty
Introduction During recent years new percutaneous revascularisation procedures in angioplasty have spread throughout the world (1, 2, 9, 10, 11, 16). With increasing application, the interest in direct intraluminal imaging of obliterating vascular processes has increased, an the one hand to carry out therapeutic control of angioplastic interventions, an the other hand to complete the Eindings of angiographic examinations.
Erste klinische Erfahrungen mit einem neuen AngioskopieSystem zur Diagnostik peripherer Gefäß -Veränderungen Die konventionelle Angiographie gewährt einen globalen Überblick über die regionale Gefäßanatomie, genaue Information kann jedoch nur indirekt aus der Kontrastgebung geschlossen werden. Das Bild der Angioskopie erlaubt demgegenüber eine direkte Beurteilung des Gefäßsystems. Um unsere Erfahrungen mit der Angioskopie zu erweitern, haben wir ein neues MikroCardio-Angioskopie-System eingesetzt, welches im einzelnen aus folgenden Komponenten besteht: CCD-Farbkamera (360000 Bildpunkte); hochflexible, resterilisierbare optische Sonde (1,4-0,6mm Durchmesser), in denen 10600-6000 Glasfasern inkorporiert sind, wobei der Betrachtungswinkel zwischen 140°, 70° und 50° variiert und ein Fokusabstand von 2 mm bis unendlich ermöglicht wird; Hochleistungslichtquelle und Führungskatheter mit aufblasbarem Ballon. Mittels bekannter Technik (intermittierende Blutflußblokkierung, kontinuierliche Spülung mit NaCI-Lösung) wurden in 36 Fällen und bei 27 Patienten vor und nach Desobliteration die Arteria femoralis untersucht. Mit Hilfe des Angioskops war es möglich, in 88% der Fälle das Ergebnis der Intervention zu kontrollieren. Kleinere Intimalefzen, wandständiger Thrombus und Intimaaufbrüche konnten sicher dargestellt werden. Die Quantifizierung von Stenosen gelang ebenfalls in 88 % der Fälle. Bei 8 Patienten wich der angioskopische Befund vom konventionellen Angiogramm ab. In 14 % der Fälle sahen wir nach angioskopischer Kontrolle des Rekanalisationsergebnisses die Notwendigkeit der Einleitung einer lytischen Therapie. Die Angioskopie bietet die Möglichkeit einer qualitativen Gefäßdiagnostik und stellt eine sinnvolle Zusatzuntersuchung zur Angiographie dar.
Conventional or computer-assisted angiographic examination permits a determination of the extent and quantity of obliterating vascular processes reaching the smallest vascular segments and is still considered a "golden standard" for the documentation of vascular changes (18). Detailed information, however, can only be obtained when contrasts are visible. In 1965, Vollmar published the results of the successful application of intraluminal endoscopical examination in vascular surgery for the first time, whereby initially rigid endoscopes were used with large lumina and restricted
This paper was presented in part at the 20`h Annual Meeting of the German Society for Thoracic and Cardiovascular Surgery, Bonn, February 1991 Thorac. cardiovasc. Surgeon 40 (1992) 33-37 © Georg Thieme Verlag Stuttgart • New York
Received for Publication: August 1, 1991
Downloaded by: Universite Laval. Copyrighted material.
Summary
1. Ennker, C. M. Gross, C. Biamino, and R. Hetzer
Thome. eardiovase. Surgeon 40 (1992)
65° or 140° 50° or 65°
flexibility (17). Further development led to increasingly thinner, more flexible and thus more easily applicable angioscopic systems (14, 15). These technical improvements of fiberoptic systems led to increased application in vascular surgery as well as in the field of interventional cardio-angiology (3, 4, 5, 13, 20). The experiences so far gained seem to indicate that the color image obtained by angioscopic examination allows direct inspection ofthe vascular lumen and reveals information on surface structure and morphology, and precisely limits the site of vascular stenosis (18). After renewed technological advance in the form of a new micro-cardio-angioscopic system (MASY*) it is now important to assess the method's clinical value in peripheral Excimer laser angioplasty.
50' 50'
Method
Technical data of the MASY system CCD Miniature Color Video Camera PAL or NTSC TV system weight: 25g Picture dots: 360000 length,5l.Bmm Driving power: 12 V, 4 W diameter: 17.5mm Minimal illumination: 3 Lux Resolution: horizontal 360 lines, vertical 420 lines Role of closure of shutter: 1II000s Flexible Probes Outer diameter (mm)
1.4 0.96 0.60 expo 0.35 expo
Glass fibers
Length 1m)
o ("m)
0.25-2.0 0.25-2.0 O.BO OBO
View angle
n
3.0-3.510,000 3.0-3.5 9,600 1.0-1.5 5,000 1.0- 1.5 2,000
Illumination Flexible light conductor: length 2.5 m, 0.10 mm High·power light source; 250W Osram halogen lamp, ca. 20000 Lux Insertion Catheter
Type
Length (em)
peripheral coronary
60-100 150
Diameter outside inside
Balloon
FB
yes (6mm) yes (3mm)
F5
1.6mm 1.2mm
~CCD
coior e.men
,
\
1'-(."b1..
ng;o.....
Fig. 1 CGD miniature color video camera with exchangable and sterilisable optical probe.
The MASY system consists ofa CCO miniature color videa camera. a highly nexible. sterilised probe (exchangable), a high-power light source. and an insertion catheter. A 25 g CCD camera with a diameter of 17.5 mm and a length of 52 mm was used. The camera produces 260000 pixels and needs at least a 3 Lux light source. Via a TV adaptor. the camera can be connected to a focusing system (2 mm to infinity) which enables simultaneous enlargement of intravascular structures during an intervention. ifrequired. At present. lWO lypcs of Oexible probe are available for clinical use: 1.4mm outer diameter with 10600 and 0.96mm with 9600 incorporated optical fibers. There are various lense systems altached to the top of the angioscope which allow a viewing of intravascular structures from an angle of 50°. 65°, and 140°. l1Iumination with nearly 20000 Lux is achieved by the application of a high-power light source (250 W Osram halogen lamp) and a highly flexible light-conductor. At the start, employing the traditonallCchnique, the femoral artery was punctured and a F9 lock was placed. The angioscope was inserted using a catheter with the lock system already pOSitioned and was moved to the desired place with the aid of visual control. In order to view the intravascular structures, it is necessary to remove the blood completely. or nearly so, from the vessels. It was therefore, necessary to develop an insertion catheter with an inflatable balloon at the tip. By intermittent blocking of the blood flow with the inflatable balloon and positioning of the angioscope at lhe lOp of the gUiding catheter, and by administering small amounts ofheparinised saline solution for continuous rinsing. it is possible to view intravascular structures directly. The described technique was used in 27 cases before and after desobliteration or the femoral artery and in 36 diagnostic procedures. The images obtained can be stored on tape and/or fixed by means of a color video printer.
Results and Discussion The first clinical experiences showed that in every case we succeeded in presenting angioscopically the segment of the vessel supposed to be viewed. in three cases the angioplasty result could be viewed only partially after laser recanalisation. In spite of sufficient rinsing of the angioscope and the use of an inflated balloon, we did not succeed in keeping the tip of the angioscope free of blood. However, in the majority of cases it was possible to view closed or stenotic vessel areas with only a smalJ amount of rinsing or sometimes without any rinsing, even for a prolonged period of time. Thus the severity of a vascular stenosis could be diagnosed with certainty angioscopically (in 88 %). In 8 cases (12%)the * A. D. Krauth, Hamburg
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34
angiographic findings clearly deviated from the intravascular documentation of the vessel obstruction: evaluation of angiographic findings resulted in a less severe degree of stenosis than was actually present and confirmed by angioscopy, also thrombotic wall coverings remained undetected by angiography. The presentation of the morphology of arteriosclerotically changed vascular areas was possible in aU remaining cases in a technically impressive form. Through the insertion ofthe angioscope after desobliteration of the femoral artery, the results obtained could be viewed directly. Intimal wall lesions with fiaps, wall dissection, and even intimal ruptures could be shown. The vascular wall lesions were unrelated to the interventional procedure performed, however they occurred less often when laser angioplasty alone had been applied. The surface structure of the arteriosclerotic changes (smooth, intact, rough, crater-shaped) and the extent of these could be described reliably and in detail. Especially after interventional procedures, we succeeded in obtaining information on the mobility of newly formed intimal flaps and on thrombotic remnants or additional thrombi in the vascular wall. Dissections after PTA could he recognised by angioscopy in every case. It was impressive to note how occlusions of a mainly thrombotic nature could be diagnosed and differentiated from sclerotic closures. In cases of thrombotic developments in the vascular wall after performance of vascular recanalisation (14 %), we applied local thrombolytic follow-up therapy; however vascular closures mostly showed a heterogenic composition of thrombotic and sclerotic material. Summarising, it can be said that a major advantage of percutaneous angioscopy consists of the possibility of qualifying vascular diagnosis. By direct viewing of the vessels, additional morphological information can be gained about type, components, and progression of the arteriosclerotic vascular changes. One limit of the procedure is that a differentiation between sclerotic plaques was only partially possible as angioscopy is solely a descriptive type of examination. Evaluation ofour investigations shows that the morphologic presentation of the pathologic anatomical findings succeeded in over 90% of cases in a technicaJJy perfect way, so that the pathological findings could be clearly distinguished from normal vascular conditions. This included recognition of the structure of the plaque surface (for example rough, crater-shaped, or smooth) as well as an assessment of mobility within the blood flow. We classified our results into categories with the aid of the already existing angioscopic classifications of findings (18). It remains unclear to what extent angioscopical findings and clinical symptoms can be correlated. There is still a controvery in the literature about whether it is possible to quantify obstructive vascular segments (8, 12, 19). This is partially due to the fact that an angioscopic assessment ofthe severity ofluminal narrowing depends on the exact coaxial positioning ofthe optical probe within the vascular lumen, and on the applied rinsing pressure of the rinsing liquid. On the other hand, information on the extent of stenotic vascular segments must be assembled from a composition of angioscopic images, as very often not the whole of the vascular cross-section can be presented at once. Quantitatively results can be obtained through optical distortions in relation to the view from the far angle of the point of the probe or when the angioscope is applied outside the focal area (18). Analysis of our angios-
Thorae. eardiovase. Surgeon 40 (1992)
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Fig. 2 View of the MASY camera-catheter ready for use
Fig. 3 Highly flexible angioscope of 0.96 mm outer diameter for use with FS blue insertion catheter.
Fig. 4 Angioscopic system MASY with color TV monitor, camera-steering appliance, high·power light source, and color video printer.
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First Clinical Experiences wilh a New Angioscopie System
Thome. eardiovase. Surgeon 40 (J 992)
J. Ennker, C. M. Gross. G. Biamina, and R. Hetzer
Fig.5 75 %stenosis of lumen of the superficial femoral artery before and after Excimer laser angioplasty. The patient had suffered for several years from peripheral arterial closure (PAC), until his walking ability was limited to a maximum of 150m,
Fig.8 Severe stenosis of the superficial femoral artery in the lower third of the femur. Deviating from this: 50% stenosis of the lumen in the angiogram. Comparing the angioscopic picture with these findings, one notices anearly complete closure of the vessel with only slit·like lumen. The severity of PAC combined with a walking distance reduced to 100m could thus be better correlated than with conventional angiography in this 60·year·old patient.
Fig. 6 Same patient: By means of laser catheterisation and subsequent con· ventional balloon angioplasty, recanafisation of asevere stenosis was achieved. It is clearly visible that, after peripheral transluminal balloon angioplasty (PTA), an intimal dissection took place with "buckle" formation and circumscribed thrombotic layers.
Fig.9 Mainly sclerotic closure before and after Excimer laser recanalisation. Top left a collateral branch is visible.
Fig.7 Same patient: Final results of asuccessful laser angioplastywith subsequent ba!loon·angioplasty of a 70% stenosis of the superficial femoral artery. The blueish border of the angioscopic picture is caused by the blue insertion catheter. The recanalised superficial femoral artery is completely open for blood flow and shows some accumulation of thrombotic wall layers.
copical findings of stenoses revealed that quantification could be achieved and that these findings partially deviated significantly from the angiographic findings (case example 11). This was also observed by other groups (19), for example White et al., who in 67 intraoperative angioscopic examinations of peripheral vessels and 17 bypass grafts could determine a significant difference between angioscopy and angiography in 21 % of the cases. Likewise, in two cases he found stenoses that the angiographic examination had not shown, as well as artefacts in the preoperative angiogram, and remnants of thrombi after thrombembolectomy. In our examination of peripheral vessels. we did not encounter vascular spasm which has often been considered a major complication of angioscopy (6) by other groups. The same can be maintained with regard to induced embolisalion and vascular perforation. We therefore consider the procedure to be particularly safe with a low rate of complications.
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First ClinicalExperiences with a NewAngioscopic System
Isner, J., and R. Clark: Laserangioplasty: Unravelling the Gordian Knot. J. Am. Coll. Cardiol. 7 (1986) 705-711 10 Kensey, K., J Nash, C. Abrahams, K. Cake, and C. Zarius: Recanali-
zation of Obstructed Arteries using a Flexible Rotating Tip Catheter. Circulation 74 (1986) II-457 11
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References
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1 Bauriedel, G., and B. Höfling: Adjunctive Angioscopy during Percutaneous Atherectomy. European Heart J. 9 (1988) Suppl. A: 132
2 Beck, A., und N. Nako: Angioskopische Kontrolle der perkutanen Gefäßendoprothese. Erfahrungsbericht über ein speziell entwickeltes transmurales Gefäßendoprothesenmodell und dessen angioskopische Kontrolle in situ. Cor. Vas. 3 (1988) 119-125 3 Chaux, A., M. Lee, C. Blanche, R. Kass, T. Shermann, A. Hickey, F. Litvack, W. Grundfest, J. Forrester, and F. Matloff.: Intraoperative CoronaryAngioscopy. J. Cardiovasc. Surg. 92 (1986) 972-976 4 Fleisher, H. L., B. W. Thompson, and T. McGowan: Angioscopically monitored Saphenous Vein Valvulotomy. J. Vasc. Surg. 4 (1986) 360-364 Forrester, J. S., F. Litvack, and W. S. Grundfest: Laser Angioplasty and Cardiovascular Disease. J. Am. Coll. Cardiol. 57 (1986) 990-992 6 Forrester, J S., F. Litvack, W. Grundfest, andA. Hickey: APerspective of Coronary Disease seen through the Arteries of Living Man. Circulation 75 (1987) 505-513 7 Forrester, J., A. Jakubowski, A. Hickey, F. Litvack, and W. Grundfest: Coronary and Peripheral Vascular Angioscopy. In: Vogel, J., and S. King, ed.: Interventional Cardiology: Future Directions. St. Louis-Baltimore-Philadelphia-Toronto, Mosby, 1989, pp 36-53 0 Hombach, V., M. Höher, A. Hannekum, M. Hügel, B. Wutan, H. Höpp, und H. Hirche: Erste klinische Erfahrungen mit der Koronarendoskopie. Dtsch. Med. Wschr. 111 (1986) 1135-1140
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Lee, G., M. Chan, R. Keda, M. Lee, R. Reis, J. Hick, J. Dukisch, W Baumer, E. Hanna, and D. Mason: Laser Therapy of Coronary Artery Obstruction. Cardiol. Clin. 3 (1985) 93-100 Lee, G., H. J. Garcia, P. Corso, M. Chan, J Ring, A. Pichard, K. Lee, R. Reiss, and D. Mason: Correlation of Coronary Angioscopic to Angiographic Findings in Coronary Artery Disease. Am. J. Cardiol. 58 (1986) 238-241 Seeger, J M., and G. S. Abela: Angioscopy as an Adjunct to Arterial Reconstructive Surgery: A Preliminary Report. J. Vasc. Surg. 5 (1986) 315-320 Tanabe, T., A. Yokota, and S. Sugic: Cardiovascular Fiberoptic Endoscopy: Development and Clinical Application. Surgery 87 (1980) 375-379 Towne, J.: Vascular Endoscopy: Useful Tool or Interesting Toy? Surgery 82 (1977) 415-419 Vallbracht, C., B. Süss, H. Awiszus, L Prignitz, G. Liermann, J. Kollath, H. Landgraf W. Schoop, M. Kaltenbach: Low Speed Rational Angioplasty - Acute Results and Complications in 33 Patients with Chronic Obstruction. European Heart J 9 (1988) (S 1) 333
Vollmar, J., K. Junghanns: Die Arterioskopie. Langenbecks Arch Klin Chir 325 (1969) 1201
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Wendt, Th.: Neue Einblicke - Angioskopie und Mikroendoskopie. Frankfurt am Main, Theo Hofmann 1990 19 White, G. H., R. A. White, G. E. Kopchok, S. R. Klein, S. E. Wilson: Intraoperative Video Angioscopy compared with Arteriography during Peripheral Vascular Operations. J. Vasc Surg 6 (1987) 488-495 20 White, G. H., R. A. White, G. E. Kopchok: Angioscopic Thromboembolectomy: Preliminary Observations with a Recent Technique. J Vasc Surg 7 (1988) 318-325
Dr. Jürgen Ennker Deutsches Herzzentrum Berlin Augustenburger Platz 1 D-1000 Berlin 65 Germany
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Undoubtedly, the inspection of various vascular sections can be repeated with the aid of angioscopy and does not require a lot of time. In contrast to conventional angiography, neither patient nor investigator is burdened with radiation, nor is the patient exposed to the risk of multiple contrast-fluid applications. Angioscopy, in our opinion and the opinion of other working groups (7), is an important and useful addition to angiography, enhancing qualitative diagnosis. In the Future, especially in the field of coronary artery intervention, the question whether there is a correlation between angioscopic findings and clinical symptoms must be considered and the therapeutic strategy determined accordingly. An attempt to answer this will be our working group's next task.
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