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A flexible, fiberoptic device, fitted with an inflatable distal balloon, has been used to directly visualize the great veins, right cardiac chambers, pulmonary arteries, and experimental emboli in vivo in the dog. Insertion and manipulation of the device have been well-tolerated. The angioscope has significant potential for investigative and clinical application.
PURPOSE: Balloon aortoscopy has been described for viewing aortic endoluminal anatomy and guiding aortic stent placement in animals. We report the first clinical use of this technique to visually inspect the proximal portion of a 1-year-old endovascular aortic graft, its proximal fixation stent, and its relationship to the renal arteries. METHODS: The aortoscope is a modified fiber-optic endoscope that is fitted over the lens with a transparent, saline-filled balloon for blood displacement. Its performance was evaluated in a 62-year-old woman who had a Parodi-type Dacron/modified Palmaz stent endoluminal graft implanted to exclude an infrarenal aortic aneurysm in 1994. One year later, during an angioplasty procedure for symptomatic left subclavian and left common iliac artery stenoses, the 1-year-old endoluminal graft was inspected with the balloon-tipped angioscopic assembly. RESULTS: Introduced via the left brachial artery, the aortoscope provided a panoramic view of the endoluminal surface through the solution-filled balloon. The endoluminal aortic graft was clearly identified, as were both renal artery orifices proximal to the graft. The surface of the proximal stent was smooth and without exposed metal. No complications occurred with the angioscopy technique. CONCLUSIONS: Aortic angioscopy can be used to evaluate endoluminal aortic grafts and endoluminal anatomy. It provides clear, magnified views that may be useful for guiding precise placement and assessing the function and healing of endoluminal devices in the aorta.
The efficacy of radiofrequency (RF) angioplasty for recanalization of arterial thrombosis was assessed angioscopically in five dogs. A thrombus was induced by balloon injury of the left femoral artery. Within two hr, thrombi led to total occlusion of the artery in three dogs, subtotal occlusion in one, and about 70% obstruction in one. A metal-tipped catheter, with a tip size of 2.0 mm x 5.7 mm, was advanced into the thrombus and RF at 13.56 MHz was delivered repeatedly with gradually increased energies. The arterial lumina were recanalized or enlarged in all dogs. The thrombus surface had a shaggy appearance, and were dark (charring), or mixed dark and white in color. There were relatively large variations in the energies required; 140 J in one, 200 J in two and 250 J in two. The present results suggest that thrombotic arterial occlusion, such as acute occlusion complicating balloon angioplasty, can be treated with RF thermal angioplasty. Angioscopy provided detailed information about thrombus surfaces. The variations in required energies indicate the inability to control the thermal effect by energy settings alone. A more sophisticated method such as measurement of tip temperature will be able to overcome this difficulty.
Angioscopic observation of the peripheral pulmonary arteries was performed in 14 patients with chronic lung diseases (male 9/female 5, age 70.8 +/- 8.3 years, pulmonary tuberculosis sequelae 6, chronic bronchitis 4, chronic pulmonary emphysema 3, pneumoconiosis 1). The blood flow was stopped by the inflated balloon of a 7F guiding catheter, and then the peripheral pulmonary arteries (inner diameter 1.0-4.5 mm) were observed with a fiberoptic catheter (outer diameter 0.7 mm). In 10 out of 14 patients abnormal findings were obtained, which included redness, erosion, ulceration of the vascular wall, thrombus, fibrous tissue, and occlusion of the lumen. The incidence of abnormal findings tended to be higher in chronic bronchitis and pulmonary tuberculosis sequelae than in chronic pulmonary emphysema. These results suggest that 1) various changes including "vasculitis" and thrombus exist in the peripheral pulmonary arteries of chronic lung diseases, and 2) that angioscopy may provide the detailed information about both the vascular wall and the lumen which cannot be obtained by pulmonary angiography.
Since the introduction of ultrathin angioendoscopes into clinical application conventional or digital angiography have been controlled by using the same approach like in angiography. In dogs and angiography patients this new angioscopic method for arteries without surgical intervention has been developed. The approach is transfemoral. Endoscopy is combined with angiography, percutaneous transluminal angioplasty (PTA), thrombolysis, thrombus extraction and a new kind of stents and their application. An ultrathin endoscope with an outer diameter of 1.6 mm and working channel of 0.35 mm is used. Guide wires, contrast media and drugs for local thrombolysis can be applied through this channel. The endoscope is placed into the region of interest under fluoroscopic control and view is obtained by using 0.9% NaCl for decreasing blood flow. Endoscopy is documented by video or by a high-speed camera. It was possible to demonstrate the proceedings of dilatation, recanalization, local lysis, stent-application and thrombus-extraction.
Angioscopy was used during in situ saphenous vein bypass grafting in seven patients. We were able to visualize valve incision, immediately identify and correct incomplete valvulotomy, identify side branches as potential arteriovenous fistulas, and assess distal anastomotic integrity. We encountered no retained valve cusps after angioscopy, as verified by Doppler ultrasound and completion angiography. Angioscopy verified distal anastomotic integrity in all patients with distal vein grafts large enough to accept the angioscope. Angioscopy requires minimal time, is relatively easy to use, serves as an adjunct to Doppler ultrasound and completion angiography, and has future potential as a therapeutic tool.
A 45-year-old man was admitted with the diagnosis of acute inferior myocardial infarction. After successful thrombolytic therapy, coronary angiography showed TIMI grade 3 flow with the filling defect and haziness on the infarct-related coronary segment. Repeat coronary angiography and coronary angioscopy were performed on the 28th hospital day. Coronary angiography showed 50% stenosis of the luminal diameter of the right coronary artery. Coronary angioscopy showed a white plaque with ruptured cap which occupied one third of the circumferential coronary artery. The torn ends of the cap were longitudinal, and projected into the lumen during the cardiac cycle. Plaque rupture and thrombus formation are important in the pathogenesis of acute coronary syndromes, although the mechanism of plaque rupture is still controversial. The present angioscopic findings seem to support the concept that circumferential tension or mechanical stretch from part of the coronary artery causes the longitudinal fissure at the weakened site of the plaque cap.
Colors in video representations of angioscopic images are up until now described by an human observer. Differences in settings of the monitor and the inherent poor ability of the human eye to classify colors objectively results in a very poor intraobserver as well as interobserver variability. A PC-based method is described to measure colors in a video image and to present the results in a novel C-diagram. Results with this method for standard calibrated colors are given. Possible sources of error are discussed and methods to minimize these errors are presented.
Superficial femoral vein valvuloplasty (SFV) under direct angioscopic vision without venotomy was designed and performed in 18 patients (20 limbs), suffering from primary SFV valve incompetence and the primary popliteal vein valve insufficiency. The indication of the operation is that the valves developed completely inborn, but with the effects of postnatal pathogenic factors, the leaflets prolapsed and became redundant, irregular diastema between leaflets emerged and the valve-ring dilated. The operation has several advantages: (1) Angioscopy confirms primary venous valve incompetence. (2) The technique precludes venotomy and valve exposure, reducing the rate of postoperative venous thrombosis. (3) The operation eliminates the blindness of kistner's external surgical technique, overcoming its empiricism. The initial clinic use of the technique has shown that it is of excellent short-term effect without complications.
Ultrasonic energy has been shown to be able to disrupt atherosclerotic plaques and thrombi. The authors used an ultrasonic angioplastic technique developed by the group in 10 patients with a femoral arterial occlusion. The ultrasonic angioplasty was attempted before surgical bypass using a 130 cm long titanium guide wire with a 0.8 mm diameter and a round distal tip measuring 2 or 2.5 mm. Angiographic and angioscopic examinations were performed before and after the procedure in 9 patients. It was not possible to perform the angioplasty in 1 patient. Angioscopy showed that the proximal part of the occlusion consisted of atheromatous material in 3 cases and of thrombus in 6 cases. Angiography showed complete restoration of flow in 4 cases; distal flow was very slow in 4 cases and no distal run-off was observed in 1 case. Angioscopy showed residual stenosis at the site of entry in only 1 case. In 3 cases, the artery had no significant residual stenosis. In the other 5 patients residual stenosis was present and angioscopy showed persistence of strands of fibrin and small thrombi. These results show that ultrasonic angioplasty was capable of recanalising an occlusion in 9 out of 10 patients with partial or total disruption of thrombi. At the present stage of development of this system, balloon angioplasty would be an essential complement in most cases in order to obtain normal flow without significant residual stenosis. The manoeuverability of the guide wire and the relatively small size of the round distal tip explain why not all the thrombi could be treated.(ABSTRACT TRUNCATED AT 250 WORDS)
Systemic administration of newer antiplatelet agents such as the GP IIb/IIIa agent ReoPro (Centocor BV Leiden, The Netherlands) has been shown to decrease the early incidence of recurrent ischemia and recurrent myocardial infarction. The currently approved protocol for administration of ReoPro involves an initial weight adjusted bolus followed by a systemic infusion over the next 12 hr. The systemic administration is proposed as the only route of administration because it is stated that the drug must be exposed to circulating platelets. An alternative approach would be to deliver ReoPro locally and allow the platelets to disaggregate only when in contact with the local arterial wall. The optimal method of monitoring the efficacy of such a strategy is to visually assess the presence of platelet rich or red blood cell rich thrombus using angioscopy. We report our initial experience in 12 patients who received local administration of ReoPro using currently approved catheters for local administration of agents into coronary arteries who were evaluated before and after intervention using intracoronary angioscopy. None of the patients received a subsequent 12-hr infusion. There was successful resolution of thrombus in 11 of 12 patients. Recurrent ischemia occurred in one patient without myocardial infarction.
UNLABELLED: To study the immediate effects of prolonged total balloon inflation during PTCA, 41 patients (44 lesions) with chronic stable angina were randomized for prolonged sequential inflations (three to five inflations of 3 to 5 min each, for a total duration of > or = 12 min, group 1, n = 20 lesions) or 'standard' sequential inflations (three to five inflations of < or = 1 min each, for a total duration of < or = 3 min, group 2, n = 24 lesions). The mean duration of total balloon inflation time was 958 +/- 129 s in group 1 vs 205 +/- 46 s in group 2. Results of angioplasty were assessed on both angiography and percutaneous transluminal coronary angioscopy performed immediately after the procedure. High quality imaging of the coronary lumen and lesion morphology was possible on angioscopy in all patients without any complications. Post-PTCA angiographic percent diameter stenosis was significantly less in group 1 compared to group 2: 26 +/- 10% vs 36 +/- 8% (P < 0.05). On angioscopy, flaps were seen in 16 patients in group 2, but in only six in group 1 (P < 0.02). There was no difference in the incidence of thrombi on angioscopy between the two groups (group 1: nine cases, group 2: 10 cases). Sensitivity of angiographic detection of flaps and thrombi was poor: 10% and 12% respectively. One patient in each group developed a longitudinal dissection, detected on both angiography and angioscopy. CONCLUSIONS: (1) prolonged sequential balloon inflations lead to less residual luminal stenosis after PTCA, with a decreased incidence of intimal flaps in comparison with standard inflations. (2) Post-PTCA transluminal coronary angioscopy is safe and offers better assessment of luminal effects of PTCA than angiography.
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Recently, percutaneous transluminal angioscopy has been clinically used. We describe the evaluation of atherosclerosis by angioscopy. In observation of aortic and peripheral arteries, color of the luminal surface is yellow in the lesion without endothelial fibrosis, whereas, it is white with endothelial fibrosis. A variety of findings such as endothelial flap, endothelial thickening, mural bleeding, mural or occlusive thrombi are observed in the atherosclerotic lesions. It is difficult to detect these findings by angiography. In observation of coronary arteries, color of the luminal surface is yellow or white and often associates spiral folds in the early stage of atherosclerosis. Plaques are classified to two categories. One is the complex plaque characterised by endothelial flap, rupture of atheroma, ulceration, mural thrombus and usually observed in patients with unstable angina or myocardial infarction. Another is the regular plaque without those findings and observed in patients with stable angina. Angioscopy is useful for evaluation of atherosclerosis.
Intracoronary stents appear promising for treatment of focal vein graft lesions, but their use may be limited by the presence of intraluminal thrombus. This report describes the use of percutaneous coronary angioscopy to identify the presence or absence of intraluminal thrombus and to guide interventional therapy with transluminal extraction coronary atherectomy (TEC) and stenting in a patient with a complex vein graft stenosis.
Several valvulotomes are currently available to achieve valvular disruption; however, studies comparing the efficacy of these endoluminal instruments are lacking. This prospective study evaluates the efficacy and safety of the three most commonly employed valve cutters: the Hall, LeMaitre, and Mills valvulotomes. A total of 30 in situ greater saphenous vein bypass grafts were included in this investigation. Valvular disruption was attempted with either the LeMaitre (11 cases), Hall (12 cases), or Mills (7 cases) valvulotomes. Subsequently, angioscopy was employed to assess the completeness of valvulotomy and to identify vein wall injury. Incomplete disruption of one or more valve complexes was identified in 2 of 12 (17%) grafts in the Hall group, 10 of 11 (91%) grafts in the LeMaitre group, and 0 of 7 grafts in the Mills group (p < 0.01). Intact valve cusps were noted in 2 of 36 (5.5%) valves, 31 of 42 (74%) valves, and 0 of 38 valves after valvulotomy with the Hall, LeMaitre, and Mills instruments, respectively (p < 0.01). A total of three valvulotome-related injuries occurred; two injuries were noted in conjunction with the Hall instrument, one was associated with the Mills valvulotome, and no injuries were detected after use of the LeMaitre instrument (p = 0.33). These data demonstrated a significantly increased incidence of retained valve cusps when the LeMaitre valvulotome was used. No significant difference in the rate of vein wall injury was noted in the three groups. Thus this study suggests that the LeMaitre instrument is not as effective as either the Hall or Mills valvulotomes for achieving valvular disruption.
Angiography and angioscopy were used to examine arterial luminal changes induced by experimental vasospasm. The right common carotid artery of the dog was perfused with Krebs-Henseleit solution at a constant pressure, 3,4-diaminopyridine (DAP), a selective potassium channel blocker was applied on the adventitia, and the luminal changes were observed with angiography and angioscopy. Angiographically vasospasm (defined as a reduction in the internal diameter to less than 50% of the control value) was always induced by the topical application of 5 X 10(-1) mol/L DAP. The internal diameter decreased to 25% +/- 7% (mean +/- standard error, n = 6) 15 minutes after the application. The vasospasms propagated 2.7 +/- 0.6 and 1.1 +/- 0.3 cm downstream and upstream, respectively. Angioscopy showed that the lumen narrowed gradually and concentrically. Perfusion of the artery during vasospasm for 15 minutes with a backflow of blood from the contralateral artery resulted in thrombosis at the spastic segment. The results indicate that carotid vasospasm can be constantly induced by DAP, thrombosis occurs in the spastic artery, and angioscopy is useful for serial observation of the luminal changes induced by vasospasm.
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