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PubMed1991

[Experimental studies on argon laser angioplasty].

To evaluate the safety and efficacy of recanalization of the occlusive arterial diseases by Argon laser, we investigated the effects of the laser irradiation using bare-ended probe (BEP) and metal-tip probe (MTP) on human cadaveric aorta and canine femoral arteries with thrombotic occlusion. In case of the BEP, the incidence of perforation of the arterial wall was high as compared with the MTP. However, laser angioplasty with angioscopic guidance could reduce the perforation rate, and made it possible to observe the new channel recanalized by laser. In case of the MTP, it was confirmed that the smaller MTP showed higher tip temperature and was more effective on plaques under the same laser energy. Optimal laser energy for single ablation was from 15J to 25J in case of 2.0mm tip and from 30J to 40J in case of 2.5mm tip. Application of the MTP equipped with thermal feedback control system could avoid the excessive thermal damage in comparison with the conventional MTP. It was considered that optimal temperature of the MTP equipped with thermal feedback control system ranged between 200 degrees C and 300 degrees C. It was concluded that laser angioplasty would be a useful treatment for the occlusive diseases of the peripheral arteries.

Angiography↗
PubMed1991

Endovascular management of arterial intimal defects: an experimental comparison by arteriography, angioscopy, and intravascular ultrasonography.

To determine the feasibility of the endovascular management of intimal defects while comparing the accuracy of arteriography with angioscopy and intravascular ultrasonography, we developed an in vivo model of arterial intimal flaps. In 10 superficial femoral arteries of five anesthetized mongrel dogs, intimal flaps were constructed and then imaged by arteriography, angioscopy, and intravascular ultrasound. A flexible microbiopsy forceps was used to remove each intimal flap under angioscopic guidance. Arteriographic lumen diameters were measured and cross-sectional areas calculated. Corresponding measurements by angioscopy and intravascular ultrasound with reduction in luminal area at the flap were obtained by use of computerized planimetry. Uniplanar arteriography identified 60% (6/10) of the intimal flaps, whereas angioscopy and intravascular ultrasound demonstrated 100%. Lumen diameter (in millimeters) measured by arteriography (3.4 +/- 0.6) correlated significantly with measurements by angioscopy (3.5 +/- 0.5, r = 0.77) and intravascular ultrasound (3.5 +/- 0.6, r = 0.96). Similarly, lumen area (square millimeters) by arteriography (9.2 +/- 2.9) correlated with measurements by angioscopy (8.9 +/- 2.2, r = 0.82) and intravascular ultrasound (8.6 +/- 2.7, r = 0.91). Reduction in lumen area by the flap by angioscopy (37 +/- 7%) and intravascular ultrasound (33 +/- 8%) also correlated significantly (r = 0.72). The intimal flaps were removed successfully in all 10 arteries as confirmed by arteriography, angioscopy, and intravascular ultrasound. We conclude that the endovascular management of intimal defects is possible. Additionally, angioscopy and intravascular ultrasound accurately evaluate lumen diameter and area while providing direct assessment of intimal defects.

Animals↗
PubMed1990

[Angioscopy and angioplasty of the iliac and femoral arteries].

Angioscopy is a technique of endoscopic investigation of the vascular lumen and its contents, which we have coupled with iliac and femoral angioplasty. The material comprises 3 main elements: the angioscope, the TV-monitoring assembly and the infusion system. No complication was recorded in a series of 94 angioscopies (47 iliac, 44 distal femoral and 3 grafts) performed over a period of 18 months. The technical quality of the images obtained was good in 90% of cases (85/94). Angioscopy revealed lesions that had either been nonvisualized or underrated by angiography, and played a determinant role in 16% of cases (15/94), whereby the therapeutical procedure could be modified accordingly.

Angioplasty, Balloon↗
PubMed1990

[A new technique of pulmonary arterial angioscopy: capnoangioscopy. An experimental study].

From animal experiments (n = 10), the authors describe a new technique of pulmonary arterial angioscopy. A balloon-fitted catheter is introduced into the trunk of one of the pulmonary arteries. A small caliber angioscope with an end capable of being propped up is then pushed within the lumen of the catheter. Intraluminal visualization of the pulmonary artery and its branches cannot begin until after the balloon is inflated to arrest blood flow and the visualization chamber is cleared by sterile carbon dioxide. The quality of the image obtained is similar to that of bronchial endoscopy, making is possible to examine at length the walls of the proximal and distal pulmonary arteries up to a caliber of 2.5 mm, and to detect blood clots. Pulmonary angioscopy is tolerated to the same extent as right heart catheterization. Potential applications of this technique are diagnosis of chronic cor pulmonale and treatment of pulmonary embolism.

Animals↗
PubMed1989

[Vascular permeability and microcirculation in patients with hemorrhagic fever associated with renal syndrome].

Vascular permeability and microcirculation (MC) were studied in 25 patients with hemorrhagic fever associated with the renal syndrome (HFRS). A considerable increase in vascular permeability for liquid and protein was recorded during oligoanuria and polyuria. These parameters slowly returned to normal with recovery. Investigation of MC identified the presence of changes mainly occurring in the intra- and extravascular parts of MC: turbidity of the angioscopic background, hemorrhages, spread sludge, atonia of the venules, winding of all groups of the vessels, aneurysms of the venules, and so forth. The increased vascular permeability and MC impairment are important components of the pathogenesis of HFRS which should be taken into consideration during institution of the pathogenetic treatment.

Adult↗
PubMed1989

[Possibilities of arterioscopy].

Today, technically optimized fiberoptical systems have become available for direct visualization of the arterial inner wall. The increasing significance of interventional revascularization techniques opens the door to new adjuvant diagnostic and therapeutic indications for arterioscopy, in addition to the earlier mainly intraoperative use. Especially for vascular wall reconstruction with percutaneous atherectomy, the angioscopic identification of residual intraluminal plaque material helps to optimize the procedure. On the basis of our own experience, a critical evaluation of arterioscopy is presented.

Arterial Occlusive Diseases↗
PubMedDate not supplied

Intraoperative fiberoptic angioscopy to evaluate the completeness of pulmonary embolectomy.

Intraoperative angioscopy was performed in three patients who underwent pulmonary embolectomy for massive pulmonary embolism. Angioscopy followed conventional techniques such as extracting the clot by a gallstone forceps, using a Fogarty catheter in the pulmonary tree or squeezing of the lungs. The rationale for angioscopy was to assess the result of these usual "blind" techniques. In two patients residual thrombus was detected and removed under direct visual control. Our initial experience suggests that intraoperative angioscopy appears to be useful in the detection of residual thrombus material, especially in the asanguinous, arrested heart. The small size of the angioscope allows easily access to the secondary, and up to the tertiary pulmonary branches. Clots can be visualized and extracted under direct visual control.

Adolescent↗
PubMed1989

[Thrombosis in unstable angina. Is there a role for thrombolytic agents?].

Intracoronary thrombosis is more and more considered as a major etiological factor of unstable angina (UA). The physiopathological diagram from ulceration of the plaque to unstable then stable thrombosis is based on many arguments: pathological (Falk-Fuster), biological, angioscopic (Forrester) and finally angiographic; numerous studies have demonstrated the frequency of non-obstructive coronary thrombi in UA. Their frequency is directly related to the delay in control, in relation with the last painful episode, indicating the spontaneous lysis of the clot. This role suggests the beneficial effect of a thrombolytic treatment. Several non-randomized studies (Vetrovek, Mandelkorn, Gotoh, Vermeer) demonstrate reduction of the clots after thrombolysis. But considering spontaneous lysis, only randomized studies published to date (Gold, Topol and Nicklas) report encouraging results. More extended studies are necessary to specify the beneficial effect and the exact haemorrhagic risk of this treatment and the probable place of additional tests like transluminal coronary angioplasty (TCA) and aortocoronary by-pass.

Angina Pectoris↗
PubMed1987

A pathophysiologic basis for the clinical classification and management of unstable angina.

Recent clinical observations have extended our classification of unstable angina to include new groups of patients now recognized at high risk of subsequent infarction. Patients with non-Q wave myocardial infarction and those with early postinfarction ischemia share a prognosis similar to that of patients with crescendo angina or with acute coronary insufficiency. Unstable angina after coronary angioplasty and after coronary artery surgery also form particular subsets of patients. Pathologic, coronary angiographic, and coronary angioscopic studies have extended the role of the obstructive atherosclerotic plaque to include a dynamic component to explain the unstable state. Recognized dynamic components are rapid progression of the disease, active vasomotion, plaque fissuring, and thrombus formation. Activation of platelets and blood coagulation factors may play a major role in triggering the syndrome. Our therapeutic approach has also become more specific for the correction of the cause of the disease. Our understanding of unstable angina now appears to be at a turning point, and a pathophysiologic basis for its clinical classification and for its management may soon be available.

Adrenergic beta-Antagonists↗
PubMed1988

Clinical application of percutaneous transluminal angioscopy. Comparison of findings in percutaneous transluminal angioplasty, thrombolysis, thrombus-extraction and stent-application.

Since the introduction of ultrathin angioendoscopes into clinical application, it has been possible to subject the findings of conventional or digital angiography to objective verification. In dogs and in patients, this new angioscopic method for visualization of arteries without surgical intervention has been carried out. The approach is transfemoral. Endoscopy is combined with angiography and, when indicated, percutaneous transluminal angioplasty (PTA), thrombolysis, thrombus extraction and insertion of a new type of stent. An ultrathin endoscope with an outer diameter of 1.6 mm and a working channel of 0.35 mm is used. Guidewires, contrast media and drugs for local thrombolysis can be employed through this channel. The endoscope is placed in the region of interest under fluoroscopy and direct visualization is obtained by using 0.9% NaCl for decreasing blood flow. Image recording is achieved by video or high-speed camera. With this method, the intraluminal events of dilatation, recanalization, local lysis, stent application and thrombus extraction can be visualized.

Angioplasty, Balloon↗
PubMed1988

[Intraoperative fiber optic angioscopy during cardiovascular surgery].

The usefulness and limitation of intraoperative angioscopy in the field of cardiovascular surgery were investigated based on our clinical experience. Considerable leakage of cardioplegic solution through the aortic valve due to valve regurgitation was angioscopically demonstrated when the infusion pressure in the aortic root was less than 10 mmHg. This indicates that the cardioplegia must be infused with an aortic pressure of above 20 mmHg for appropriate myocardial protection. After thromboendarterectomy on the arteriosclerosis obliterans, fixation with the edge of the residual intimal flap to the arterial wall was performed correctly under direct visualization. The status of thrombus organization in deep vein thrombosis was evaluated. Even after complete thrombectomy, iliac compression was still demonstrated. Blood in the cardiovascular lumen can be easily cleaned by saline flushing. However, careful attention to fluid overloading must be employed when the observation period is prolonged.

Aortic Valve↗
PubMed1987

The use of lasers in vascular and cardiac surgery. Clinical review.

Use of lasers is routine in medical fields such as ophthalmology and dermatology, but in spite of intensive research in recent years, its role in cardiac and vascular surgery still remains to be determined. Laser energy can vaporize atherosclerotic plaques in human arteries obtained at necropsy. Fiberoptic catheters have been constructed to deliver the laser energy to atheromas at a distance from the arteriotomy. The healing of the arterial wall after laser treatment is rapid and results in complete reendothelialization. Lasers have been used in patients undergoing coronary surgery as well as peripheral vascular reconstructions. In some cases, the percutaneous approach has also been used. In these clinical series, the laser treatment was in almost all cases followed by either transluminal balloon angioplasty or by-pass operation. Complications after laser treatment include vessel perforation, reocclusions, thrombosis, or aneurysm formation. The development of more advanced fiberoptic catheters and better understanding of dosimetric parameters are promising features to avoid these complications as well as development of methods for steering of the laser catheter itself and means for "real time" diagnosis (e.g. angioscopes, spectroscopic diagnosis). The future use of lasers in cardiac and vascular surgery seems promising, especially as an alternative to balloon angioplasty.

Cardiac Surgical Procedures↗
PubMed1988

Endoscopy of the gallbladder as control of gallstone therapy with methyl-tert-butyl ether.

We report on a 36-yr-old woman with six gallstones measuring 2.1 cm each. Within 21 h of methyl-tert-butyl ether (MTBE) treatment, the stones had dissolved to a small amount of residue. As could be seen from cholesterol concentrations of samples of aspirated gallbladder bile and MTBE fractions, the dissolution process was slow to begin with, and gained momentum during hours 6-11, after which it decelerated. We discontinued treatment after 20 h, since the stone residue showed no change. Cholecystoscopy performed with an Edwards angioscope via a catheter showed that there were no stone remnants, but that there were flat polyps on the gallbladder wall. One hour later, we stopped the therapy. Cholecystoscopy is a useful method of assessing the results of MTBE treatment.

Adult↗
PubMed1988

The effect of valvulotomy on the flow rate through the saphenous vein graft: clinical implications.

Potential differences in flow rates between reversed and in situ saphenous vein bypass grafts were evaluated. One hundred ten greater saphenous vein segments containing isolated valves were examined with fiber-optic angioscopy during pulsatile and nonpulsatile flow. Valve competency was determined, and the degree of luminal obstruction caused by the valve during reversed flow was calculated with caliper measurements of the video image. Flow measurements were obtained before and after valvulotomy, in reversed and nonreversed vein orientations. Increased flow rates occurred during pulsatile irrigation only, after valvulotomy in vein segments with diameters less than 2.5 mm (p less than 0.001, Bonferroni t test). In these small-diameter vein segments, the flow rate in reversed valve-intact vein was 94.4 +/- 28.9 ml/min (mean +/- 1 standard deviation), the flow rate in reversed valve-disrupted vein was 136.4 +/- 36.5 ml/min, and the flow rate in nonreversed valve-disrupted vein was 137.8 +/- 31.3 ml/min. In 22 vein segments, luminal obstruction caused by the intact valve was measured angioscopically. A small valve orifice was found to be related to a large increase in flow rate after valvulotomy (p less than 0.02, least-squares regression). In addition, veins with diameters less than 2.5 mm have significantly smaller valve orifices compared with veins with diameters greater than 2.5 mm. These results present important clinical implications as the number of distal extremity reconstructions increases.

Blood Flow Velocity↗
PubMed1986

Intraoperative angioscopy of saphenous vein and coronary arteries.

During coronary artery bypass graft operations, the saphenous vein graft and native coronary arteries in 17 patients were examined with a 1.7 mm fiberoptic catheter to determine the feasibility of the procedure and its potential for clinical application. Good to excellent visualization in 10 of 11 proximal and 10 of 10 distal coronary anastomoses was obtained promptly and consistently. Good visualization of native coronary arteries was obtained in only six of 11 vessels. Three of three coronary arteries were visualized through the completed distal anastomosis, whereas only three of eight vessels could be visualized directly through the arteriotomy site before completion of the distal anastomosis. The image quality improved with operator experience. Vessel distention by cold crystalloid solution during catheter visualization was also important for obtaining better images. Limitations of the current "state of the art" fiberoptic catheters include the large size relative to the usual dimensions of the native coronary vessels, a lack of perfusion channel, and the absence of an angulation or guiding system. Potentially, angioscopic catheters may be useful as an instructional aid during bypass operations or as a diagnostic tool in monitoring arterial status after thrombolytic intervention, balloon angioplasty, or laser therapy.

Cardiac Catheterization↗
PubMed1987

Direct vision valvulotomy in in situ venous bypass.

The autogenous saphenous venous bypass is accepted as an optimal procedure for distal arterial reconstruction. However, serious complications, including incomplete valvulotomy, laceration of the venous wall and persistent arteriovenous communications, are found in in situ bypasses. To avoid these complications, a new and simple technique using an angioscope in the in situ venous bypass has been developed. Angioscopy prevents tearing of the vein wall and avoids inaccurate incision of the valves.

Endoscopy↗
PubMed1985

[Effects of the argon laser on atheromas. Preliminary study on post-mortem arterial samples].

The effects of argon laser radiation of human atheroma were studied in vitro. Lesions produced were craters from total tissue volatilization surrounded by a thin zone of coagulation. The degree of tissue destruction was related to the energy used and the direction of the laser beam in relation to the atheromatous stenotic lesion. These findings confirm that it is possible to destroy the atheroma under controlled conditions, but at the non-negligible risk of perforation. By allowing visual control, the angioscope should ensure increased safety in use and provide hope for future applications of this method by the percutaneous route in the treatment of established atheromatous disease.

Argon↗
PubMed1994

[Coronary disease: should images be treated?].

Precise digitized images of the coronary arteries displaying the dimensions of high risk stenoses and giving objective measurements of their contours and density can be provided by coronarography. On-line angioscopic images of tissue flaps floating in the lumen, recent or structured thrombi, artery wall dissections, plaque ruptures, deep fissurations and sub-intimal haemorrhages demonstrate, in live colour, the pathophysiological mechanisms of coronary artery stenosis. Histological sections of the artery wall, without biopsy, can be visualized with endocoronary echography offering a global view of the wall and differentiating all the physiological layers including the intima and the internal elastic lamina, the blood-wall interface, the media and the adventitia. Our technical imaging capacity is impressive, but is anatomic imaging synonymous with coronary circulation? Certainly not. Sophisticated imaging techniques have led us to associate the severity of the stenosis with its effect on myocardial irrigation, but today therapeutic decisions require not only considering coronary anatomy but also downstream consequences which can be evaluated by measuring coronary artery flow on both sides of the stenosis. Carried on the tip of the angioplasty guide, a piezo-electric crystal emits and receives a Doppler signal. The data is processed in real time giving a complete pattern of blood flow velocity and describing diastolic and systolic flow, differences between upstream and downstream flow, and the effect of pharmacological or physiological tests such as maximal dilatation to measure coronary vascular reserve. Transstenosic pressure measurements complete the diagnostic armentorium. Thus therapeutic decisions can now be made not only on the basis of precise anatomic imaging, but also on functional imaging, giving a complete view of the pathophysiology of the coronary arteries and the effect of disease on myocardial blood supply. It is now up to us to optimize these imaging techniques and to propose treatments which provide patients with coronary artery disease with the best benefit-risk-cost ratio.

Angioscopy↗