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A method of endoscopic investigation of vascular structures directly through flowing blood.

BACKGROUND: Noninvasive cardiovascular diagnosis has improved immensely due to key technological refinements such as digital subtraction angiography, ultrasonography, Doppler flow analysis, and magnetic resonance imaging. Each of these methodologies provides a unique image of the cardiovascular system but will not permit surgical maneuvers or repairs during real time imaging. Our group has developed a new method of endoscopic visualization of the luminal surface of blood vessels directly through flowing blood without interference of the blood or vessel wall. This opens new possibilities in both diagnosis and surgical interventions. METHODS: Transluminal imaging through flowing blood was performed in normal animals using laser frequency light delivered and retrieved via conventional fiberoptic angioscopic instruments. The reflected light energy was reconstructed into a viewable image using a specialized method of optical data processing and filtering systems. Unlike conventional angioscopy, displacement of flowing blood was not needed as the images were obtained with higher frequency laser light. RESULTS: A total of 20 canine experiments were performed between 1996 and 1997 using our endoluminal imaging system. The images obtained revealed details of luminal surfaces, although primitive and low resolution with this first generation of technology. Images of the topography of the femoral, axillary, and subclavian arteries and veins, as well as several intracardiac structures (aorta and aortic valve) were successfully obtained without trauma or physiologic consequence to the animal. CONCLUSIONS: Using conventional fiberoptic angioscopes coupled with laser light of differing wavelengths, it was possible to image the interior of vascular structures through flowing blood. This method visualizes the intraluminal surface in real time and is dependent only on the delivery and capacity of the endoscope. The implications for future cardiovascular diagnosis and corrective surgical procedures are widespread.

Angioscopy↗

Long-term peripheral stent evaluation using angioscopy.

To evaluate incorporation of peripheral artery stents into the arterial wall, we performed angioscopy on 13 patients fitted with Palmaz endoluminal stents. Of the 15 stents inspected, 5 were in the iliac artery, 9 in the femoral artery and 1 in the popliteal artery. The indications for placement were occlusion in 4 cases and high-grade stenosis in 11 cases including 3 restenosis after balloon dilatation and 1 restenosis after surgery. In 9 cases prosthesis insertion was preceded by laser treatment (Trimedyne Nd:YAG Cardiolase 4000). The decision to use a stent was based on radiologic findings in 3 cases (residual stenoses, dissections) and on angioscopic visualization in 7 cases (2 dissections, 5 flaps). In the remaining cases stent placement was performed electively. The only postoperative treatment was antiplatelet therapy (Ticlopidin). At the time of examination, the mean duration of placement was 6 months (extremes: 2 and 12 months). Inspection was made using Sopro-Meadox angioscope with a 0.75 mm probe mounted on an occlusive balloon for stents in the iliac artery and with a 2.2 mm probe with a working channel and sometimes a deflecting device for stents in the femoral or popliteal artery. Angioscopy was successful in all cases. Angiography was always performed at the same time as endoscopy. Endothelialization was observed in all cases. It appeared as a uniform and smooth whitish layer with a thickness proportional to the duration of placement. Endothelialization was most rapid in femoropopliteal arteries, total coverage being achieved within 4 months. Endothelialization took the longest on medial side of the iliac artery which may remain partially exposed after 12 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Vessel Prosthesis↗

[Angioscopy in peripheral vascular diseases].

Angioscopy is a useful investigation in patients referred for vascular surgery. The material has been improved over the last few years to make available angioscopes with external diameters ranging from 0.55 to 3.2 mm. The angioscopes are either rigid, composed of two groups of fibre optics (image and light transmission) or orientable and more complex. Both systems may carry operating channels. The angioscopy may be performed peroperatively or percutaneously. Other essential equipment includes catheter guides, balloon catheters, counterpulsation balloons or perfusion pumps. This investigation is used for diagnostic evaluation but when used peroperatively it may also help guide therapeutic intervention. Angioscopy is complementary to ultrasonic and radiological methods of vessel imaging.

Catheterization↗

Continued experience with intraoperative angioscopy for monitoring infrainguinal bypass grafting.

Intraoperative angioscopy provides direct, in vivo, three-dimensional visualization of the interior of the blood vessels and grafts. We have shown previously that with the application of the basic principles of irrigation and with a dedicated irrigation pump that routine intraoperative angioscopy can be performed with consistent high quality results during lower extremity revascularization. In our total experience with angioscopy as a monitoring procedure during infrainguinal bypass grafting, 259 intraoperative angioscopies, during 63 femoropopliteal and 196 distal bypass grafts, were performed from May 1, 1987, to October 31, 1989. Mean total irrigation fluid used in the study was 448 ml (range, 0 to 1400 ml) with good visual quality in more than 80% of the studies. The overall failure rate was 1.5%. No complications were directly attributable to the insertion of the angioscope or the use of the pump. Based on the angioscopic findings, 124 clinical or surgical decisions were made in 259 of the angioscopies. The incidence of graft failure in this study was 8.1% (less than 30 days) and 4.8% (greater than 30 days) with a mean follow-up of 272 days. Direct inspection of the interior of the graft and native vessels at the time of surgery has resulted in the recognition of previously unsuspected vein-graft pathology. Angioscopy as the sole monitoring procedure for infrainguinal bypass grafting is safe, effective, and reliable and may not only improve the durability of these grafts but may improve our understanding of the pathogenesis of graft failure and of the progression of the underlying atherosclerotic disease.

Adult↗

[Endoscopic vein preparation in peripheral bypass surgery].

The autogenous saphenous venous bypass is accepted as an optimal procedure for distal arterial reconstruction. For the past ten years the "in situ" technique was developed, and excellent results have now been achieved. The achilles heel of the method is the complete and atraumatic disruption of the valves. We use an angiofiberscope (Olympus PF 22A) with an outer diameter of 2.2 mm, being introduced through the proximal exposed end of the saphenous vein. Through the distal end or a side branch a modified Mill's Valvulotome with a flushing channel is moved upwards to the angioscope. Every valve cusp is incised under direct vision in a retrograde direction. Simultaneously relevant tributaries are angioscopically located and ligated through small skin incisions.

Arterial Occlusive Diseases↗

Intraoperative coronary angioscopy: development of practical techniques.

Techniques and equipment for intraoperative coronary angioscopy were studied in the coronary arteries and cardiac veins of excised and in vivo animal hearts. These studies then allowed development of safe, practical techniques for human clinical use. In coronary artery bypass operations, multichannel angioscopes of 2.3 to 2.8 mm diameter gave the best results for examinations of the bypass vein and anastomosis, whereas smaller optical fibers of 1 mm diameter were required for inspection of the native coronary artery. Abnormalities were detected in 11 of 48 (23%) coronary bypass anastomoses, and significant discrepancy in the degree of coronary artery stenosis as compared with the preoperative angiogram was revealed in 2 patients. The authors concluded that a new design of ultrafine, multichannel angioscope would be more suitable to the different requirements for inspection of both the anastomosis and the recipient artery.

Animals↗

Flexible endoscopy in primary dye testing of the lacrimal system.

The Olympus PF-22 angioscope was used to examine the inferior meatus during primary dye testing in 80 lacrimal systems in 48 patients. Dye testing was done bilaterally in 32 subjects with no known abnormalities of lacrimal excretory function; it also was performed on the apparently normal contralateral side of 16 patients with unilateral epiphora. Dye was observed in the nose in 79 of 80 lacrimal systems (99%). Dye was not observed in one patient, who appeared to have a dysfunctional lacrimal excretory system. Primary dye testing of the lacrimal system is reliable when the Olympus PF-22 angioscope is used to examine the inferior meatus.

Adult↗

The use of carbon dioxide gas to displace flowing blood during angioscopy.

Carbon dioxide (CO2) gas is a safe and effective arterial contrast agent that images arteries by displacing blood. The use of CO2 gas to displace blood during angioscopy may improve intraoperative angioscopy and allow percutaneous angioscopy. To study this, 46 angioscopic evaluations in the femoral arteries of four dogs were done without inflow occlusion. The ability of CO2 gas to clear the flowing blood was compared to a high-pressure infusion of saline solution. Carbon dioxide gas successfully displaced flowing blood in 20 of 25 evaluations (80%) as compared to three of 21 evaluations (14%) with infusion of saline solution (p less than 0.0001). After the CO2 gas infusion was stopped, the image remained clear for 9 +/- 1 seconds. When saline was used, the image was clear only as long as the infusion was continued. The quality of clear images for the two media were similar through the eyepiece of the angioscope, but images observed through the motion picture camera had better contrast and depth of field in CO2 gas. The use of a CO2 gas infusion can clear the field of flowing blood without the risk of volume overloading and potentially allow performance of a successful percutaneous angioscopy.

Animals↗

[Diagnostic significance of angioscopy in patients with coronary heart disease].

Coronary angioscopy (CA) using ultrathin fiberscopes was performed in 30 patients with coronary heart disease during cardiac catheterization and in 11 patients during bypass surgery. For percutaneous CA the angioscope was introduced from the femoral artery through a 9F guiding catheter. During short-time occlusion of the coronary ostium by the tip of the guiding catheter the viewing field was flushed with Ringer's solution. Intraoperative CA was performed both by the retrograde and antegrade way during flushing with cardioplegic solution. Percutaneous CA was successful in 57% of patients. 13 patients showed eccentrically and irregularly shaped stenoses and 3 of these patients had an additional plaque rupture. In 2/5 patients CA after PTCA revealed intimal dissections not visualized by angiography. Intraoperative CA was successful in 9/11 patients. In 3 patients nonocclusive thrombi were found at the site of the coronary lesion. Additionally we studied the efficacy of angioscopic guidance during intravascular radiofrequency application. In 11/11 thrombotically occluded peripheral vessels this new method allowed a nearly complete recanalization. There was only one perforation of the vessel. We conclude, that CA is a powerful diagnostic tool providing prognostically relevant information in the diagnosis of coronary heart disease.

Animals↗

Direct vision valvulotomy for nonreversed vein graft.

A new and easy technique using an angioscope in a nonreversed, isolated vein bypass is suggested herein. Direct vision valvulotomy with an angioscope in nonreversed vein graft saves operating time, prevents tearing of the vein wall and inaccurate incision of the valves.

Evaluation Studies as Topic↗

Angioscopy as an adjunct to arterial reconstructive surgery: a preliminary report.

To date our use of angioscopy as an adjunct to in situ vein grafting, arterial embolectomy, femoropopliteal bypass surgery, and laser recanalization has been studied in 11 patients. Three angioscopes have been used: a 1.7 mm optiscope, a 2.8 mm laser optiscope, and a 3.2 mm bronchoscope. Scopes were introduced through an arteriotomy and a clear field maintained by continuous saline infusion. Twenty-four angioscopic evaluations were performed in the 14 patients studied. Adequate visualization was achieved with all three scopes. Angioscopy showed total atherosclerotic occlusion of six superficial femoral and popliteal arteries, intimal flaps in two arteries, thrombus in two arteries and one graft, adequate valvulotomy in three saphenous veins used for in situ bypass grafting, and removal of thrombus after embolectomy in one artery. With the 2.8 mm laser optiscope, the optical fiber used for laser recanalization could be positioned at the site of arterial occlusion before lasing and recanalization were done under direct vision. The 1.7 mm scope could be passed through the recanalized artery to inspect the channel and confirm communication with the artery distal to the occlusion. Thus, angioscopy appears to be potentially useful as a diagnostic device in arterial occlusive disease and as an adjunct in in situ saphenous vein grafting or laser recanalization of occluded arterial segments.

Arterial Occlusive Diseases↗

Angioscopy guided in situ bypass versus angioscopy guided non reversed bypass for infrainguinal arterial reconstructions. A comparison of outcome.

In situ bypass grafting depends on an adequate ipsilateral greater saphenous vein. To profit from a tapered, valveless conduit in legs without an adequate greater saphenous vein, we routinely used the contralateral saphenous vein non reversed. In some reconstructions to the infrageniculate popliteal and the proximal anterior tibial artery we used the non reversed instead of the in situ technique because of the distance between the natural course of the saphenous vein and the recipient artery. This retrospective study compares the outcome of 48 in situ bypasses to the outcome of 66 non reversed bypasses. Endoluminal manipulations in all veins were visually controlled using an angioscope. The two groups of bypasses (in situ versus non reversed) did not differ concerning age, sex, risk factors, operative mortality, indication for surgery and distribution of the recipient arteries. There was a tendency for a lower wound complication rate in "in situ" compared to non reversed bypasses (10% versus 27%; p = 0.086). There were no differences in cumulative primary and primary assisted patency rates between the two groups after two years. We prefer the angioscopy guided in situ technique for reconstructions to infrageniculate arteries because of a low wound complication rate and excellent patency rates. In the absence of an adequate ipsilateral saphenous vein and in reconstructions to recipient arteries not presenting themselves for the in situ technique, similar results can be achieved with angioscopically prepared non reversed grafts.

Angioscopy↗

[Percutaneous angioscopy and angioplasty in the treatment of arteriopathies of the lower limbs].

Since 1987, the authors have routinely combined angioscopy with angioplasty of peripheral arteries. In a series of 251 angioplasties carried out in 191 patients, angioscopy was found to be more specific and more sensitive than arterial angiography in the etiological diagnosis of arterial stenoses and/or obstructions. Angioscopic findings modified the angioplasty procedure in 29% of cases. Using an inflatable catheter remains the most commonly used approach (230 cases); in 10 cases, this was preceded by thromboaspiration and in 4 cases by dotterization. Angioscopic support was useful in carrying out difficult manoeuvres (monitoring of the angioplasty in 4 cases, correct orientation of the guide into the lumen in 14 cases, installation of an endoprosthesis in 9 cases, arterial biopsy in 5 cases and sampling of an atheroma in 8 cases).

Angioplasty, Balloon↗

Angiovideo-assisted hemodynamic correction of varicose veins.

OBJECTIVE: Evaluation of the feasibility and utility of angioscopy in the hemodynamic correction (French acronyms is CHIVA) of primary varicose veins disease. EXPERIMENTAL DESIGN: Prospective evaluation of 25 patients, undergoing hemodynamic correction of primary varicose disease with intraoperative videoangioscopic guide. Patients have been selected according to criteria emerged from a prospective study that we had previously conducted. Follow-up lasted 1 year (range 8-18 months). SETTING: Department of Surgery, University of Ferrara, Italy. Institutional practice. One-day surgery. PATIENTS: Their selection has been carried out in our Vascular Laboratory. The adopted clinical criteria of selection were: Primary varicose disease of the long saphenous vein territory, no previous thrombophlebitis and/or sclerotherapy. Doppler cw and Duplex criteria followed were: competent deep venous system, long saphenous vein diameter minor than 10 mm and incompetent perforating veins diameter minor than 4 mm. INTERVENTIONS: 25 hemodynamic corrections according to the CHIVA method described by Franceschi. An angioscope, introduced through a distal collateral of the long saphenous vein, permitted the precise interruption of the venous-venous shunts and of the superficial venous system, just below the perforators chosen as re-entry points in the deep venous system. MEASURES: Clinical: varices and symptomatology reduction. Duplex and Doppler cw: detection of the superficial blood flow re-entry, in the deep venous system, through the perforators and identification of recurrences or new refluxes. Pre and postoperative Ambulatory Venous Pressure and Refilling Time have also been measured. RESULTS: In 20 patients symptoms and varices relief were recorded (80%), in 5 patients varices reduction was observed only during walking (20%). In 2 of these latter patients there was no re-entry through the perforators, with a recurrent sapheno-femoral reflux in 1 of them. Early complications recorded were: 2 long saphenous vein thrombosis (8%); 7 ecchimosis (28%) when heparine/saline solution had been used for angioscopic clearance. CONCLUSIONS: Intraoperative angioscopy is feasible and useful when the hemodynamic situation is complex and the Duplex map is difficult to be interpreted by the surgeon. In this series the second look percentage rate has been minor compared to the percentage rates published so far by other authors.

Adolescent↗

[Initial experience with angioscopy in infrainguinal reconstruction using the in situ saphenous vein technique].

The authors report on their experience with lower limb revascularization using the in-situ saphenous vein bypass grafting in four patients with angioscopically assisted valvulotomy. They describe the surgical technique employed and outcome of the procedure. The discussion section examines the pros and cons of the technique of in-situ saphenous vein bypass with angioscopically assisted valvulotomy (ISB + AV) compared with the standard technique of reversed bypass (RVB).

Adult↗

Angioscopy after laser and balloon coronary angioplasty.

OBJECTIVES: Percutaneous intracoronary angioscopy was used to study the morphologic changes occurring in coronary arteries after balloon or laser angioplasty. BACKGROUND: Angioscopy is thought to provide details of the coronary vessel lumen and the inner wall. METHODS: Coronary lesions were studied in 44 patients with a 4.5F Imagecath angioscope before and after each interventional procedure. Balloon and laser angioplasty were performed in 21 (group I) and 23 patients (group II), respectively. There was no difference in age, gender or angiographic lesion appearance before the procedure between the two groups. RESULTS: Circumferential visualization of the target lesion was successfully completed in 17 group I and 19 group II patients. A larger lumen than that observed at baseline was seen in all 17 group I and in 13 of the 19 group II patients. Tissue remnants were observed in all group I and II patients. Laser irradiation resulted in characteristic sharp-edged craters. Dissection was identified in 2 of 19 patients before versus 9 of 19 patients after balloon angioplasty (p < 0.05) and in 0 of 23 patients before versus 4 of 23 patients after laser angioplasty (p = NS). Subintimal hemorrhage was observed in 3 of 19 patients before versus 11 of 19 patients after balloon angioplasty (p < 0.05) and in 2 of 23 patients before versus 4 of 23 patients after laser angioplasty (p = NS). The frequency of hemorrhage was higher in group I than in group II (11 of 19 vs. 4 of 23, respectively, p < 0.02). CONCLUSIONS: Angioscopy provides valuable information on lesion morphology after coronary interventions. Balloon dilation results in a high rate of dissection and subintimal hemorrhage. Laser angioplasty is able to ablate obstructing tissue and results in a lower rate of subintimal hemorrhage than balloon dilation.

Aged↗

[Pulmonary thromboendarterectomy with video-angioscopy and circulatory arrest: an alternative to cardiopulmonary transplantation and post-embolism pulmonary artery hypertension].

The best predictor of poor or suboptimum outcome from pulmonary thromboendarterectomy (PTE) is insufficient relief of obstruction, especially in the lower lobes. The aim of this study is to emphasize that the use of video-assisted angioscopy may increase the quality of PTE and thus improve outcome. PTE included a median sternotomy, intrapericardial dissection limited to the superior vena cava, institution of cardiopulmonary bypass, deep hypothermia and sequential circulatory arrest periods. PTE was always bilateral and performed through two separate arteriotomies of both main intrapericardial pulmonary arteries. A rigid 5 mm angioscope connected to a video camera was introduced through the arteriotomy into the lumen to increase the visibility and perform the video-assisted endarterectomies of all obstructed segmental branches, including normally inaccessible anterior segmental branches. Between January 1996 and December 1997, 48 patients with severe postembolic pulmonary hypertension had PTE. Patients were in New York Heart Association (NYHA) class II (n = 2), III (n = 28) or IV (n = 18) with the following hemodynamics: mean pulmonary arterial pressure (PAP) 53 +/- 13 mmHg, cardiac index 2.16 +/- 0.5 L/min/m2, pulmonary vascular resistances (PVR): 1,152 +/- 414 dyne.s-1.cm-5. Six patients died from alveolar hemorrhage (n = 1), high residual pulmonary pressure and rethrombosis (n = 4) and hypoxic cardiac arrest (n = 1). The functional outcome in surviving patients was as follows: (NYHA) class I (n = 24), II (n = 16) or III (n = 2) with improved hemodynamics: mean pulmonary arterial pressure: 30 +/- 9 mmHg, cardiac index: 2.78 +/- 0.5 L/min/m2, pulmonary vascular resistances (PVR): 484 +/- 159 dynes.s-1.cm-5. Video-assisted angioscopy allows much improved quality and degree of pulmonary endarterectomy. This expands the indications to include patients with previously inaccessible distal disease and candidates for heart-lung transplantation.

Adult↗

Diagnostic and interventional angioscopy.

As an imaging modality, angioscopy provides a simple method for the careful evaluation and treatment of the lumen of native vessels and bypass grafts. When used as a diagnostic study, angioscopy can provide more accurate information regarding the flow surface than conventional tests, such as angiography or duplex imaging. It can significantly enhance the ability of the surgeon to detect flow surface problems. With the recent advance in endovascular tools, angioscopically guided luminal intervention has become an increasingly useful approach to many vascular problems. More precise treatment of endoluminal abnormalities and a reduction in incision length and soft-tissue dissection can result in decreased patient morbidity and extended patient benefit.

Angioscopes↗