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At least 271 records · Page 15Linked to original sources
PubMedDate not supplied

Carbon dioxide column angioscopy: a new endovascular imaging technique.

A new angioscopic technique with a CO(2) gas medium for prolonged viewing sessions in the carotid artery is described. A stationary column of CO(2) gas, angled 17-30 degrees subhorizontally and buoyed against a balloon catheter, can be safely maintained. During 10-20-min sessions in dogs, endothelia, thrombi, stent filaments, coils, and an intimal flap were visualized. This technique eliminates the need for continuous saline infusion, which has prevented the application of angioscopy in the carotid artery.

Angioscopes↗
PubMed1994

Angioscopy in femoral popliteal bypass graft.

Angioscopy is part of a new armoury of minimally invasive 'keyhole' surgery. Like other 'scopes' it enables the surgeon to have a direct view of the interior of the body with greatly reduced surgical intervention. An angioscope is an ultra thin multi-bundle fibre scope which has manual flexibility. Its tiny diameter (1.4mm at smallest) enables the scope to be introduced into the distal vessels of the lower leg. As with other scopes the view is seen on a video screen monitor. So, angioscopy enables surgeons to access the interior of body vessels for the first time, providing vital information on vessel condition during operative procedures.

Angioscopes↗
PubMedDate not supplied

[Percutaneous coronary angioscopy: 200 observations in 100 candidates for angioplasty].

Due to the recent technological advances, it is possible to perform percutaneous coronary angioscopy in a straightforward fashion in most patients. To know the safety and usefulness of this technique we present 200 observations in 100 patients candidates for coronary intervention. We used a coronary angioscope (Baxter, Edwards LIS Division), that can be placed using the conventional technique for percutaneous coronary angioplasty. The system incorporates a proximal occluding balloon, and distally a movable optical fiber. Case selection considered non-ostial coronary segments relatively straight. It was possible to obtain adequate images in 86 percent of cases. The technique is safe in experienced hands: there were two cases of ventricular fibrillation, and two cases of local dissection occurred, none of these associated with clinical consequences. No myocardial infarction, surgery or death, related to this procedure occurred. Valuable diagnostic information is derived from angioscopy as the method provides some histopathological correlation. Stable plaques are usually uniformly white or yellow. Unstable plaques are yellow and ulcerated. Thrombus can be easily recognized in acute coronary syndromes. Also in percutaneously treated segments, the final result and the presence of dissection or hemorrhage can be visualized. Coronary percutaneous angioscopy is safe and brings useful clinical information. Its applications in the clinical practice are still to be determined.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

[Intraoperative coronary angioscopy after unsuccessful percutaneous dilatation angioplasty and the implantation of an intracoronary stent].

In all coronary arteries after failed PTCA with subsequent stent insertion the stenosed and dilated part of the vessels were inspected. We found dissections in 17/25 coronary lesions as well as thrombus adherent to the wall of the vessels in 8/25 cases. The morphology of the coronary stenosis was compared with the preoperative cine-angiogram. The angioscopic images after failed PTCA and subsequent stent-insertion showed severe wall dissections which were located beyond the inserted stent. In none of the cases was stent-implantation the sufficient treatment of coronary lesions. In all patients we performed coronary artery bypass grafting (CABG). Every coronary incision was used for peripheral anastomosis of the bypass grafts.

Aged↗
PubMed1998

Assessing outcomes, costs, and benefits of emerging technology for minimally invasive saphenous vein in situ distal arterial bypasses.

BACKGROUND: Instrumentation for a minimally invasive angioscopic in situ peripheral arterial bypass (MIAB) with catheter-directed side-branch occlusion has recently been approved for use. Despite the attractiveness of this approach (2 short incisions), benefits such as lower morbidity and shorter hospitalizations remain undocumented. To justify wide acceptance, minimally invasive surgical techniques must match conventional procedures in durability and cost while enhancing patient comfort. Often such comparisons are difficult during the implementation phase of a new procedure. OBJECTIVE: To compare the outcomes of the MIAB procedures with a concurrent group of patients undergoing conventional in situ bypass procedures. DESIGN: Retrospective review. SETTING: University medical center. PATIENT: The first 20 consecutive MIAB procedures in 19 patients performed between August 1, 1995, and July 31, 1997, were compared with 19 contemporaneous consecutive conventional in situ bypass procedures performed at the same institution. MAIN OUTCOME MEASURES: Operative time, postoperative length of stay, hospital costs, complications, primary assisted and secondary patency, limb salvage, and survival. RESULTS: The patient groups were comparable with respect to age, sex, incidence of smoking, coronary artery disease, hypertension, diabetes, renal failure, cerebrovascular disease, indication, and distal anastomosis level. The median operative time was significantly greater for the MIAB group (6.6 hours vs 5.7 hours; P=.009), and intraoperative completion arteriography more frequently showed retained arteriovenous fistulas in the MIAB group (55% vs 21%; P=.05). The median postoperative length of stay and total cost were 6.5 days and $18,000 for the MIAB group and 8 days and $27,800 for the conventional group (P > or = .05). There were no significant differences in major complications (10% in the MIAB group vs 11% in the conventional group), wound complications (10% vs 11%, respectively), primary assisted patency at 1 year (68%+/-11% vs 78%+/-10%, respectively), secondary patency at 1 year (79%+/-10% vs 88%+/-8%, respectively), limb salvage at 1 year (85%+/-10% vs 94%+/-6%, respectively), or patient survival at 1 year (89%+/-8% vs 61%+/-13%, respectively). CONCLUSION: Patients undergoing the MIAB procedure avoided lengthy vein exposure incisions without sacrificing short-term results. There was a trend toward decreased hospital stay and cost, which may be further realized as the clinical experience broadens. Although longer follow-up and larger cohorts will always be required to define durability, immediate access to outcomes and costs on small numbers of patients facilitates the early assessment of emerging technology.

Adult↗
PubMed1989

Routine intraoperative angioscopy in lower extremity revascularization.

The inability to see through blood remains the main obstacle to the widespread and routine use of angioscopy. Local irrigation with a balanced salt solution is presently the most widely used method to clear the blood. By applying basic principles of irrigation and using a unique, dedicated, irrigation pump, we found that routine angioscopy during lower extremity revascularization that yields consistent high-quality studies is feasible, clinically useful, and safe. Between May 1, 1987, and July 31, 1988, 136 intraoperative angioscopies were performed during 112 peripheral bypass procedures, 15 thrombectomies, 2 embolectomies, and 7 miscellaneous revascularization procedures. Mean total irrigation fluid used in the peripheral bypasses was 398 mL (range, 0 to 1400 mL). Good visual quality was obtained in more than 80% of angioscopies and the failure rate was only 1.8%. On the basis of the findings in 71 of the 136 angioscopies, 78 clinical or surgical decisions were made. No complications were directly attributable to the insertion of the angioscope or use of the pump.

Angiography↗
PubMed1990

Angioscopy for intraoperative management of thromboembolectomy.

Our experience with angioscopy suggests that direct visualization of the arterial lumen during thromboembolectomy procedures would provide a more reliable method of assessing luminal morphologic characteristics than angiography alone. We inspected 32 grafts (seven aortobifemoral, 18 infrainguinal bypass, and seven dialysis access fistula grafts) in 32 patients. Thirty-one patients had thrombotic events and one patient had an acute embolus. Angioscopy following standard catheter thrombectomy revealed significant amounts of retained thrombus or neointima in all thrombectomies. Angioscopic information from 18 patients with an infrainguinal bypass graft led to graft revision in six cases and placement of a new graft in 10 cases. One graft limb was replaced in seven aortobifemoral grafts, and multiple repeated thrombectomies were employed to extract debris in the remaining six cases. Repeated graft thrombectomy was also beneficial in dialysis access fistulas. Angioscopy allowed us to omit the completion angiogram and led to an improved technical result. We conclude that angioscopy is useful during thromboembolectomy procedures.

Aged↗
PubMed1991

Thrombolysis by rotational thrombectomy followed by tissue plasminogen activator: evaluation by angioscopy.

Thrombus removal using percutaneous rotational thrombectomy (PRT), followed by tissue plasminogen activator (t-PA), was studied by contrast angiography and fiberoptic angioscopy in a canine femoral artery model of thrombosis. After thrombus induction and following each treatment, comparisons were made between angioscopy and angiography for the detection of thrombus and subintimal dissection. Angioscopic images were scored in a blinded fashion for lining, protruding, or occlusive thrombus (class 1,2, or 3) as well as estimated wall coverage by thrombus. Angiograms were studied for percent diameter stenosis and the presence of flaps. Following external forceps crush injury of 18 arteries, two hour occlusion, and injection of thrombin, mean angiographic stenosis was 66%, thrombus coverage by angioscopy was 81%, and mean angioscopy class was 2.5. Following PRT, stenosis decreased to 27% (p less than 0.008), thrombus coverage was reduced to 49% (p less than 0.02), and angioscopy class dropped to 2.0 (p less than 0.07). After t-PA treatment, these values were further reduced to 25% (p = NS), 26% (p less than 0.02), and 1.3 (p less than 0.008), respectively. In comparison to angiography, subintimal dissection (seen as flaps) and thrombus (lining, protruding, or occlusive) were present significantly more often by angioscopy (p less than 0.001). It is concluded that PRT results in significant thrombolysis, apparent by angiography and angioscopy. Follow-up t-PA can produce additional, incremental thrombolysis, apparent only by angioscopy. A beneficial role for t-PA following mechanical thrombolysis is suggested by this model. The superior sensitivity of angioscopy for detection of flaps and thrombus is underscored by this study.

Animals↗
PubMed1995

Efficacy of angioscopy in determining the effectiveness of intracoronary urokinase and TEC atherectomy thrombus removal from an occluded saphenous vein graft prior to stent implantation.

Percutaneous revascularization of thrombus containing saphenous vein grafts is associated with a high incidence of acute complications. This case report describes successful revascularization of an occluded vein graft employing angioscopically guided sequential urokinase infusion, TEC atherectomy and stent implantation.

Angioscopy↗
PubMed1992

Intravascular ultrasound guided holmium:YAG laser recanalization of occluded arteries.

Current angioplasty devices are limited by arterial wall dissection and perforation, and by early recurrence from inadequate debulking of lesions. This study evaluated intravascular ultrasound (IVUS) as guidance for concentric laser recanalization of arterial occlusions. Twelve, 2-4-cm-long canine iliac artery occlusions were treated at 2 weeks (organizing thrombus) to 12 weeks (firm fibrous lesions) using a Holmium:YAG laser (2,100 nm wavelength) in free running mode, FRM, (250 musec pulse, 5 Hz), n = 9; and Q-switched mode, QSM (200 ns pulse, 6 Hz), n = 3. A 200 microns (n = 2) or 600 microns (n = 10) optic fiber was centered in the artery coaxial to a 5Fr rotating A scan IVUS probe. The fiber was positioned in the center of the artery distal to the lesion and slowly advanced through the obstruction. In 8 occlusions the same fiber was used as a guidewire for passage of either a 1.6-mm-(n = 2) and/or 3.0-mm (n = 6) diameter multifiber catheter (19 x 100 and 19 x 200 microns fibers, respectively) using FRM energy to further debulk the lesion. In all cases, IVUS guidance enabled concentric initial recanalization of occlusions, although 3 vessel perforations resulted from fiber deviation off the center of the lumen at a distance of 2 to 4 cm from the IVUS imaging element. Both QSM and FRM modes ablated tissue, with FRM modes producing more tissue fragmentation and thermal effect. IVUS images accurately diagnosed the location of lesions compared to angioscopic views and pathologic analysis of the specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Laser↗
PubMed1988

The clinical significance of coronary angioscopy in patients with coronary heart disease.

The feasibility and safety of coronary endoscopy was evaluated in three sets of investigations: in 7 cadaver hearts, in 11 patients undergoing coronary bypass surgery, and in 30 patients during routine cardiac catheterization prior to coronary balloon angioplasty (PTCA). In three of the seven cadaver hearts the lumen of the arteries appeared normal. In three diffuse atherosclerotic lesions, and in one, a high-grade, tight stenosis were observed. In nine of eleven patients in the operation room, the lesions of interest could be visualized, and high-grade stenoses were found in all. In addition, in three patients with unstable angina pectoris, fresh thrombi were seen at the site of stenosis. In six of the nine patients, the periphery of the native coronary vessel was found to have no further stenotic regions. During cardiac catheterization in 17/30 patients, the lesion of interest could be examined angioscopically, and in 13 instances the stenosis appeared excentric and irregularly shaped. In three instances, multiple ulcerations were seen in the stenotic area. In two of the five patients, intimal ruptures were found following PTCA, which could not be documented angiographically. Coronary endoscopy provides valuable additional information on the nature and appearance of atherosclerotic lesions. It can be performed clinically without great harm to the patients. Despite some limitations, it will probably become a routine diagnostic tool in patients undergoing routine coronary angiography, balloon angioplasty or high-frequency angioplasty, and coronary bypass grafting.

Angioplasty, Balloon↗
PubMed1995

Rheological significance of tandem lesions of the coronary artery.

It is not known whether the individual lesions that constitute tandem lesions of the coronary artery are developmentally or rheologically related. Luminal changes and their rheological significance were examined by percutaneous angioscopy in 44 tandem lesions of 21 patients with ischemic heart disease. Angioscopically, individual narrowing of angiographically documented tandem lesions appeared only as a tangentially expressed prominent portion of an atherosclerotic spiral fold. The directions of the fold were counterclockwise in the proximal to middle segments and clockwise in the distal segment of the right coronary artery, clockwise in the proximal to middle segments and counterclockwise in the distal segment of the left anterior descending artery, and counterclockwise in the proximal to middle segments of the left circumflex artery. The bloodstream always ran along the spiral folds in the tandem lesions. The results suggest that angiographically documented tandem coronary lesions are merely a tangential expression of atherosclerotic spiral folds and that they may act to prevent blood turbulence by generating a spiral laminal flow.

Adult↗
PubMed1993

Endovascular obliteration of in situ saphenous vein arteriovenous fistulas during tibial bypass.

Current methods of ligating venous branches during in situ vein tibial bypass are associated with significant wound complications, especially in diabetics. Making only proximal and distal wound incisions could avoid these wound problems. We report the use of endovascular techniques with coils and balloons guided by intraoperative arteriography and angioscopy to obliterate arteriovenous (AV) fistulas in three elderly diabetic patients undergoing tibial bypass. In all cases the proximal and distal vessels were first isolated and deemed suitable for bypass. The greater saphenous vein was prepared for the proximal and distal anastomosis, and angioscopically guided valvulotomy was performed. An introducer sheath was placed through a large proximal saphenous side branch for vascular access. With the use of fluoroscopy, AV fistulas were serially identified and cannulated with a guidewire. A guide catheter, passed over the wire into the side branch, served as the conduit through which coils and balloons were placed. Proximal and distal anastomoses were completed and arteriography performed. We were successful in obliterating AV fistulas in all three patients, but completion arteriography revealed additional AV fistulas requiring surgical ligation in two patients. Furthermore, operative time was increased by 1 1/2 to 5 hours. Two of three patients had wound infections, one at the proximal and one at the distal incision. All patients were discharged with a functioning bypass and no AV fistulas were seen on duplex scans. Endovascular obliteration of AV fistulas is feasible but is currently limited by prolonged operative time and incomplete obliteration.

Aged↗
PubMed1992

Technique and results of vascular endoscopy in arterial and venous reconstructions.

In an effort to maximize results, vascular endoscopy was used in our institution to monitor arterial and venous reconstructions. Since 1982, angioscopy was applied as a control method in 182 venous thrombectomies to treat iliofemoral thrombosis and 114 aortoiliac thromboendarterectomies. Of the cases with venous thrombectomy reviewed, 50% were incomplete by endoscopic evidence; of these, in 80% the remaining clots could be partly or completely removed. Additionally, in six patients a venous spur was found. Of 114 attempted aortoiliac thromboendarterectomies, only 91 could be completed. In the remainder, endoscopic evidence of persistent intimal flaps forced us to bypass the affected segments. With further miniaturization of the angioscopes, the method was also applied to check vessel repair on small-caliber arteries. In an initial study with 220 femorodistal bypasses we were unable to find a statistically significant difference of primary patency in grafts that were endoscopically controlled or not. In the learning phase with the in situ technique, we identified competent valve remnants in 40%, but this rate could be reduced to 12.7% with growing experience in valvulotomy. We conclude from our data that angioscopy is very helpful in assessing the morphological integrity of aortoiliac thromboendarterectomies and venous thrombectomies. The actual value in infrainguinal arterial reconstructions still remains to be proven.

Angioscopy↗
PubMed1991

Angioscopy of arm vein infrainguinal bypass grafts.

Between January 1988 and December 1990, 56 patients underwent 66 arm vein infrainguinal bypass grafts for limb salvage. Thirty-nine grafts were intraoperatively monitored by the standard methods of continuous wave Doppler alone (30) and arteriography (9). Twenty-seven grafts were prepared and monitored by intraoperative angioscopy. No significant findings requiring intraoperative revision or correction were noted in the grafts monitored by the standard methods. However, in those grafts prepared and monitored by angioscopy, intraluminal abnormalities of the arm veins were detected and corrected in 20/27 (74%). None of the grafts prepared or monitored by angioscopy occluded within 30 days, whereas, in those grafts monitored by continuous wave Doppler and arteriography, 7/39 failed within 30 days, a primary patency rate of 32/39 (82%) (x2 with yates correction, p = 0.055). This study shows that angioscopic preparation and monitoring of arm vein bypass grafts allows the detection and correction of unsuspected intraluminal abnormalities, which appears to improve the early primary patency of arm vein infrainguinal bypass grafts.

Aged↗
PubMed1990

Nd:YAG laser irradiation to intraluminal mass lesions of the superior vena cava under laser balloon angioscopy in an experimental canine model.

A laser balloon angioscopic procedure was developed in a canine model for intraluminal mass lesions in the superior vena cava, using an endoscope bearing a very thin balloon through which Nd:YAG laser could penetrate. The balloon was made from artificially modified natural latex rubber and well expanded with saline infused through a biopsy channel. The endoscopic image of the object obtained through direct contact of the balloon expanded with saline was clear enough to observe the internal surface or branches in not only normal, but also pathological conditions of the canine SVC. The Nd:YAG laser was able to be successfully irradiated through the balloon using this procedure which, although still in its preliminary stage, may be a useful clinical, diagnostic and therapeutic tool of the future.

Angioplasty, Balloon↗
PubMed2005

Diagnosis of anomalous origin of the right coronary artery using multislice computed tomography: evaluation of possible causes of myocardial ischemia.

Anomalous origin of the right coronary artery (RCA) is a rare condition, but may cause myocardial ischemia and sudden death. Multislice computed tomography, which allows three-dimensional visualization of the coronary artery with high spatial resolution, may be the most promising imaging modality for diagnosing this anomaly. We describe a patient with anomalous origin of the RCA arising from the left sinus of Valsalva. Volume rendering, and axial and curved multiplanar images showed stenosis in the proximal portion of the RCA that coursed between the aorta and the pulmonary artery, and an acute angled take-off of the RCA from the aorta. Three-dimensional virtual angioscopic images showed a hypoplastic RCA orifice and luminal narrowing in the proximal portion of the RCA. Multislice computed tomography was thought to be useful for detecting anomalous origin of the RCA and for evaluating possible causes of myocardial ischemia.

Aged↗
PubMed2000

Confocal laser scanning fluorescence topography: a new method for three-dimensional functional imaging of vascular structures.

Three-dimensional topography of perfused vascular structures is possible via confocal laser scanning of intravascular fluorescence. The lateral resolution is given by the spot size of the scanning laser beam (optimally 10 microm at the retina). The axial resolution, however, depends on the accuracy of detection of the surface of the fluorescent structure, which is typically one order of magnitude higher (30 microm at the retina) than the confocal resolution. The vascular structure is stained with an appropriate fluorescent dye prior to the investigation using standard systemic dye injection. Confocal scanning of the fluorescence in planes of different depths within the vascular structure under investigation leads to a three-dimensional data set. Signal processing includes passive eye tracking, lateral averaging and axial determination of the surface of the fluorescent structure. The potential of this new technique is demonstrated by showing the topography of physiological vessel structures as well as of selected vascular diseases such as cone dystrophy, RPE detachment, choroidal haemangioma and retinal laser coagulation. Confocal laser angioscopic fluorescence topography (CLAFT) measures the three-dimensional surface structure of functional (perfused) vasculature and surrounding leakage. CLAFT may help to diagnose and quantify status and time course of vascular diseases.

Contrast Media↗