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At least 487 records · Page 27Linked to original sources
PubMed1991

Angioscopically directed valvulotomy: a new valvulotome and technique.

Despite a large experience with "blind" retrograde valvulotomy in in situ vein bypass grafting, the incidence of residual competent valves remains high, and valvulotome-induced injury is common. In this study we describe a new valvulotome and technique of angioscopically directed valvulotomy and review the video tape recordings of 85 completion angioscopies of in situ femorodistal bypasses. Fifty-three vein grafts were prepared with the blind retrograde valvulotomy technique and 32 vein grafts with the new valvulotome and angioscopy. The use of the new valvulotome and technique is compared with that of the standard blind retrograde valvulotomy technique, and the normal endoluminal anatomy and incidence of primary disease in saphenous vein grafts was noted. The incidence of valvulotome-induced injury was 5/32 (15.6%) and 45/53 (85%) in vein grafts prepared with angioscopically directed valvulotomy and blind retrograde valvulotomy, respectively. Residual competent valves were found in 10/53 (18.9%) in blind retrograde valvulotomy and 0/25 of angioscopically directed valvulotomy vein grafts (p = 0.0114). In 22/53 vein grafts unsuspected primary disease was detected. Angioscopically directed valvulotomy with the new valvulotome and technique is feasible, reliable, and safe. It avoids residual competent valves, minimizes valvulotome-induced injury, and allows the detection and correction of unappreciated primary vein graft abnormalities. The new valvulotome and technique is a first step in the complete endoluminal preparation of the in situ vein graft.

Aged↗
PubMed1995

[Clinical and hemodynamic effects of external valvuloplasty of the sapheno-femoral junction].

Selected patients with primary varicose vein disease and sapheno-femoral reflux as the only point of regurgitation in the affected lower limb and duplex evidence of mobile valve leaflets underwent external valvuloplasty of the sapheno-femoral junction. Operations were performed under local anesthesia in one day-surgery. One PTFE sleeve 0.4 mm thick, in average 1.2 cm long and able to uncircle a circumference in average of 1.7 cm was put around the terminal Long Saphenous vein valve, located in the last centimeter of this vein. If also the subterminal Long Saphenous Vein valve site, located 5 cm below is dilated a second valvuloplasty was performed. In 15 case we used intra-operatory video-angioscopy guide. This examination allowed us to exclude two patients with valve damages not duplex demonstrable. Furthermore angioscopy permitted immediate demonstration of restored valvular function. Follow-up lasted on average 48 months: two early postoperative long saphenous vein thrombosis, and two late sapheno-femoral reflux recurrences were the main complications. We never observed graft infection. AVP was reduced and RT, measured by the means of LRR, had a prolongation after surgery. Both measurements had an highly significant difference from a statistical point of view, comparing pre and postoperative values. 95% of the operated patients have stable varices reduction. Long Saphenous Vein patency was recorded in 37 cases (92.5%). On the contrary, after high ligation, the fate of the saphenous vein in 21% of case is the occlusion. Symptoms of venous insufficiency disappeared completely in 80% of cases and improved in 95% of the operated patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Femoral Vein↗
PubMed1994

Transluminal extraction coronary atherectomy.

The TEC is a forward-cutting atherectomy catheter that has the unique potential to excise and aspirate atheroma, especially intraluminal thrombus. This device has been under clinical investigation for more than 6 years and received final marketing approval by the FDA for the treatment of lesions in the coronary vasculature in 1993. In the US TEC Multicenter Registry, the overall clinical and lesion successes were favorable. The success rates were similar for both native coronary vessels and saphenous vein bypass grafts. Importantly, the procedural success rates were maintained even in the presence of several unfavorable angiographic features, such as ostial location, intraluminal thrombus, and total occlusion. Further insights into the mechanisms of action of the TEC were made from studies using percutaneous angioscopy and intravascular ultrasound. Angioscopy clearly demonstrated that the TEC was indeed able to remove intraluminal thrombus, especially loosely adherent red thrombus, in a population of patients with unstable coronary syndromes. However, the TEC frequently leaves behind multiple intimal disruptions which not only create a possible nidus for restenosis but also explain the frequent hazy angiographic appearance of the vessel after TEC atherectomy. As is true for all new interventional devices, the specific niche for the TEC in interventional cardiology will best be determined in randomized clinical trials. There are several areas in which the TEC appears promising. First, this device may have a role in the management of patients with diffusely diseased saphenous vein grafts. Second, the TEC may be an effective primary therapy in lesions with intraluminal thrombus. Treatment with the TEC may then be followed by an adjunctive therapy to maximize the final vessel diameters. Finally, the TEC may be valuable in the treatment of lesions in patients with high-risk unstable coronary syndromes.

Atherectomy, Coronary↗
PubMed1997

[Venous valves in the legs: hemodynamic and biological problems and relationship to physiopathology].

Venous valves are more frequent in distal veins and venulae, providing a protecting action against blood skin reflux. Structurally simple, collagen and endothelium, they allow a cavity to be formed by distension, when occlusion occurs. Venous angioscopy can distinguish bicuspid floating valves, reinforced, reinforcing valves with free edges and seat valves as well as the presence of apertures of small collateral vessels in the sinus, of which they play a role in the filling up. Valves are inefficient in supine and in standing among 20% of the adult population. Sinuses allow vortices to be created, low recirculating zones, where blood flow move slowly in niches, at a low shear rate, independently from the main stream. A deep vortex is located in sinus, usually empty, but likely to receive red cell aggregates and leukocytes in the condition of stasis and hyperviscosity. Such a vortex is hypoxic, cause of endothelial activation. In such areas fibrin-leucocytic nidus are created, histologically recognized, of which sub-endothelium has become thick and thrombogenic. Two stages characterized its progression: stage I: a few alteration in the valves, little thrombin generation, taken over by the coagulation inhibitors: AT III, APC and TFPI. Stage II: damaged valves, local consumption of the inhibitors and extended generation of thrombin over the platelets, through factor IXa. Hereditary inhibitor deficits increase the risk (frequent factor Leyden V). When the coagulation cascade is considered, VIIa-tissue factor complex appears to be the thrombotic pathway, leading first to wall linked thrombin, uneasily reached by AT III and facteur IXa non inhibited by TFPI, therefore explaining the platelet extension. Monocytes, which can bear tissue factor, may be "lodged" inside the niches. Besides this important role in deep venous thrombosis, incompetent venous valves are responsible for the skin venous hypertension, a subsequent ground for ulcers. Their role in chronic venous insufficiency is uncertain. In the near future, venous angioscopy will bring about new findings about the pathophysiology of venous valves.

Fibrin↗
PubMed1993

Early stent occlusion is not always caused by thrombosis.

Early occlusion of intracoronary stents has been exclusively attributed to thrombosis. Using intracoronary angioscopy, we have found 2 patients in whom this common and serious complication of coronary stenting was caused by obstructive intima dissection rather than thrombosis.

Aged↗
PubMedDate not supplied

Relative characteristics of MR angiography and competing vascular imaging modalities.

This article reviews the general characteristics of several vascular imaging modalities with the purpose of identifying the distinguishing features of magnetic resonance (MR) angiography. Brief discussions of conventional x-ray film angiography, intravenous and intraarterial digital subtraction angiography (DSA), duplex and color Doppler flow ultrasound (US), computed tomographic (CT) angiography, transesophageal and intravascular US, angioscopy, and MR angiography are presented. The advantages and disadvantages of each are discussed. The general attributes and image quality features of MR angiography, intraarterial DSA, CT angiography, and US are compared. It is concluded that no single imaging modality will presently suffice for all purposes. Because of its noninvasiveness, rapidly improving image quality, and ability to directly provide velocity information, MR angiography is likely to play a role in an increasing number of clinical applications.

Angiography↗
PubMed1993

Improvement of microcirculation abnormalities in sickle cell patients upon buflomedil treatment.

The efficacy of the vasoactive compound buflomedil on previously described microcirculation abnormalities observed in sickle cell disease (SCD) was investigated using bulbar conjunctival angioscopy (BCA) and laser doppler flux metering. Eleven sickle cell disease patients at steady state were studied in a double-blind randomized parallel-versus-placebo study (5 patients were given placebo and 6 patients received 600 mg buflomedil per day for 21 days after a washout period of 15 days). The blood flux score measured by BCA improved, indicating reduced entrapment of sickle red blood cells. There was a striking improvement of reactive alterations of vasomotion in the buflomedil group, particularly in postocclusive reactive hyperemia; the half return time was also significantly reduced. These results encourage further studies with buflomedil to investigate long-term effects of this compound in SCD, potential prevention of acute vaso-occlusive events, and degenerative complications.

Adult↗
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↗
PubMed1996

Induction of thrombolysis and prevention of thrombus formation by local drug delivery with a double-occlusion balloon catheter.

The efficacy of the local delivery of an antithrombotic drug in preventing thrombosis and enabling thrombolysis was investigated in 29 dogs. An antithrombotic drug (heparin, 25 U/kg), or an antithrombin (argatroban, 0.05 mg/kg) was infused into injured canine iliac arteries, using a double-occlusion balloon catheter, and the preventive effect of the drug was evaluated. Local delivery of low-dose tissue-type plasminogen activator (t-PA; Tisokinase, 50,000 U; Kowa, Nagoya and Asahi Chemical Industries, Fuji, Japan) into thrombosed canine iliac arteries, using the same catheter, or intravenous infusion of low-dose or high-dose t-PA (30,000 U/kg) was also performed. Angiographically, stenotic thrombosis was 2% by local delivery of argatroban and 7% by local delivery of heparin (P < 0.01 vs each control; 47% and 51% respectively). Thrombotic stenosis, as observed by angiography, decreased from 91% to 9% after local delivery of t-PA, and from 94% to 52% in controls. Local delivery of t-PA effectively reduced the thrombus size (P < 0.01 vs control). After systemic intravenous delivery of low-dose t-PA, no reduction of residual thrombotic stenosis, was observed. Reduction of residual thrombotic stenosis after intravenous delivery of high-dose t-PA, was similar to that achieved by local delivery of the drug. Angioscopy demonstrated a similar trend. High-dose drug delivery reduced systemic coagulability. Local delivery of an antithrombotic drug, using a double-occlusion balloon catheter, effectively prevented thrombus formation, and local delivery of t-PA induced thrombolysis without exerting a significant influence on coagulability.

Angioscopy↗
PubMed1996

Local treatment with an antithrombotic drug reduces thrombus size in coronary and peripheral thrombosed arteries.

Since the treatment of thrombotic disease by antithrombotic drugs may be associated with bleeding complications, a local delivery technique for administration of the drug may be useful. The efficacy of low-dose local delivery of an antithrombotic drug on thrombosis was investigated in 73 dogs. The antithrombotic drug (heparin, 25 U/kg, antithrombin: argatroban, 0.05 mg/kg, or defibrinogenating agent: batroxobin, 0.05 U/kg) was infused locally to a 1-h-old thrombus, and no drug was given in controls. The effect of the local delivery on the thrombus was evaluated. Low- and high-dose systemic drug delivery was also evaluated. The mean reduction in thrombotic coronary stenosis observed by angiography was 30.3% with argatroban, 22% with heparin, and 20.8% with batroxobin (P < 0.005 vs controls). Systemic delivery of low-dose heparin or argatroban did not induce any change in thrombus size. With high-dose systemic drug delivery (heparin 250 U/kg, argatroban 0.5 mg/kg), the mean reduction of thrombotic stenosis was 15.2% with heparin and 32.8% with argatroban (P < 0.005 vs controls). In the iliac arterial thrombosis, after local delivery of the drugs, the mean reduction of thrombotic stenosis observed by angiography was 24.4% in the argatroban group, and 19.2% in the heparin group (P < 0.05 vs controls, respectively). With high-dose systemic heparin delivery, the mean reduction of the thrombotic stenosis was 13.2% (P < 0.01 vs control). Angioscopy also demonstrated a similar trend. The high-dose drug delivery reduced systemic coagulability. Thus, local delivery of an antithrombotic agent can reduce the thrombus size in the coronary and iliac arteries without having any significant influence on coagulability.

Angioscopy↗
PubMed1994

Angioscopic evaluation of valvular disruption during in situ saphenous vein bypass.

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.

Adult↗
PubMed2005

[Intraoperative monitoring in vascular surgery].

Despite the variety of possibilities to evaluate hemodynamics, ultrasound-in particular duplex sonography-is the method of choice. With an increasing number of endovascular procedures, intraoperative angiograms will remain indispensable. The method of angioscopy is reserved for individual cases. Indirect monitoring in carotid surgery will keep its significance. This includes measuring somatic evoked potentials as well as transcranial duplex sonography, with regard to the increasing importance of plaque morphology and possible neurological consequences. The general recommendation of applying at least one intraoperative control method is necessary in carotid surgery, even if intraluminal shunts are routinely implanted. In addition, quality control of the peripheral vascular system should be sufficiently documented by using one or more methods of examination. So far, in prospective randomized trials, results have not improved by applying intraoperative monitoring methods. Nevertheless, they are indispensable for the careful vascular surgeon and can help to avoid complications and revision with worse prognosis in some cases.

Aneurysm, Ruptured↗
PubMed1995

Coronary lesions at increased risk.

An acute ischemic complication will develop in approximately 7% of patients undergoing coronary angioplasty. In more than half of these patients, thrombus, dissection, or both can be identified angiographically as the underlying cause of abrupt closure; in the remaining cases, an indeterminate morphology is observed. Predictors of dissection-mediated closure include degenerated vein graft, de novo stenosis, proximal tortuosity, high lesion grade, eccentricity, longer lesion length, and angulation. Thrombus-medicated closure is most apt to occur in degenerated vein grafts, lesions related to a recent myocardial infarction, and lesions that contain thrombus before angioplasty. However, the ability of these parameters to predict risk in an individual patient is rather weak. Angioscopy has revealed that the presence of yellow plaque confers a heightened risk of major complications. Lesions that contain areas of calcium adjacent to areas to soft plaque have been identified by intravascular ultrasound as a powerful predictor a major dissection. These sensitive new imaging techniques may eventually permit the targeting of more specific therapies to the underlying cause of closure.

Angioplasty, Balloon, Coronary↗
PubMed1994

Luminal volume reconstruction from angioscopic video images of casts from human coronary arteries.

Intravascular angioscopy has been hampered by its limitation in quantifying obtained images. To circumvent this problem, a lightwire was used, which projects a ring of light onto the endoluminal wall in front of the angioscope. This investigation was designed to quantify luminal dimensions of casts from stenotic human coronary arteries and to investigate the feasibility of performing volume reconstruction. Angioscopic video recordings were made during simultaneous motorized pullback (2 mm/s) of an angioscopic catheter and light-emitting fiber through 4 epoxy casts from human coronary arteries. Quantification of the images was performed using a computerized cross-sectional area measurement system. The coronary casts were divided into cross-sectional segments of 4 to 10 mm in thickness, with the true volume of each segment determined by means of a microdispenser. Because of vessel curvature and luminal narrowing, complete visualization of the ring of light at all 1-mm-distant locations was only possible in 19 of 40 segments. For these 19 segments, linear regression analysis showed a good correlation between measured and true segmental volume (r = 0.97, y = 0.88x + 6.58 mm3, standard error of estimate = 3.48 mm3). The relative error in the measured segmental volumes was 3.9 +/- 7.1% (mean +/- SD). These initial results of endoluminal volume reconstruction demonstrate the feasibility of this technique in vitro with high accuracy and low variability, but further technical improvements are necessary to increase the success rate, especially in the quantitative assessment of vessels with complex morphology.

Angioscopes↗
PubMed1995

Local treatment with antithrombotic drugs can prevent thrombus formation: an angioscopic and angiographic study.

OBJECTIVES: This study was designed to evaluate the efficacy of local versus systemic treatment of thrombosis with various antithrombotic drugs. BACKGROUND: Local use of low dose antithrombotic drugs has been proposed as being effective and safe. METHODS: Heparin (30 U/kg), an antithrombin agent (argatroban, 0.05 mg/kg body weight) or a defibrinogenating drug (batroxobin, 0.05 U/kg) was locally infused into one side of the canine iliac artery after injury by balloon inflation. The other side was injured as a control. The efficacy of systemic delivery of high dose (heparin [300 U/kg] and argatroban [0.5 mg/kg]) and low dose drugs was also assessed. RESULTS: Sixty minutes after local treatment in 22 dogs, no thrombotic stenosis was observed by angiography in locally treated arteries (p < 0.005 vs. mean thrombotic stenosis of 27% in control segments for heparin, 25.3% in control segments for argatroban and 32% in control segments for batroxobin). Angioscopy demonstrated the same trend. In locally treated arteries, thrombus weight was significantly lower in the treated than control side. In the systemic high dose group (n = 10), angiographic thrombotic stenosis was < 5% after high dose drug delivery (p < 0.05 vs. control segments, 37.4% for heparin, 43% for argatroban). In another 10 dogs, low dose systemic delivery was not effective in inhibiting thrombus formation. Activated partial thromboplastin time and fibrinogen levels did not change with local treatment. CONCLUSIONS: Compared with systemic administration of antithrombotic drugs, local treatment is a safer and more effective method of preventing thrombosis.

Angiography↗
PubMed2005

Association between cardiac troponin T elevation and angioscopic morphology of culprit lesion in patients with non-ST-segment elevation acute coronary syndrome.

BACKGROUND: It is well known that cardiac troponin T (TnT) elevation on admission indicates a high-risk subgroup among patients with non-ST-segment elevation acute coronary syndrome (NSEACS). Although the mechanism of TnT elevation is speculated to be the microthromboembolism from unstable plaques, it has not been clarified. The aim of this study is to clarify the association between the serum TnT elevation and the angioscopically evaluated morphology of culprit lesion in the patients with NSEACS. METHODS: Among 113 patients with NSEACS who had significant coronary stenosis, 62 patients with successful angioscopic examination were prospectively and consecutively enrolled from October 2001 to August 2002. Patients were divided into 2 groups according to the serum TnT level measured before percutaneous coronary intervention: TnT-positive or TnT-negative group. Thrombus and plaque color at culprit lesion were evaluated by angioscopy and were compared between the groups. Plaque color was determined as yellow or white, and thrombus as none, small, or large. Three different definitions for TnT-positive (> or =0.1, > or =0.03, and > or =0.01 ng/mL) were used and the sensitivity and specificity for detecting thrombus was compared. RESULTS: Prevalence of thrombus, large thrombus, and yellow plaque were all higher in TnT-positive than in TnT-negative group for 3 different cutoff values of TnT. Angiographic slow-flow occurred more frequently after percutaneous coronary intervention in TnT-positive than in TnT-negative group for 3 different cutoff values of TnT. Sensitivity/specificity of detecting large thrombus were 33%/100%, 44%/91%, and 56%/83% when TnT-positive was defined as TnT > or = 0.1, > or =0.03, and > or =0.01 ng/mL, respectively. CONCLUSIONS: Serum TnT level was significantly associated with the prevalence of thrombus and yellow plaque at the culprit lesions of NSEACS. Troponin T, when positive was defined as > or =0.01 ng/mL, still have a high specificity for detecting intracoronary thrombus.

Aged↗
PubMed2004

Cardiac catheterization techniques in pulmonary hypertension.

Once considered dangerous and potentially life threatening, cardiac catheterization of the patient with pulmonary hypertension can be performed safely and provides essential information in the diagnosis and management of pulmonary hypertension. This article summarizes the modern techniques used for right-heart catheterization, selective pulmonary angiography, and pulmonary angioscopy in the evaluation of the patient with pulmonary hypertension or suspected chronic thromboembolic disease.

Angioscopy↗