Stereoselective urinary excretion of bupivacaine and its metabolites during epidural infusion

PURPOSE: Intravascular ultrasound (IVUS) was used to assess in vitro the morphologic and quantitative effects of balloon angioplasty (PTA) of the iliac artery. METHODS: Forty human iliac arteries (>/= 30% area stenosis) were studied with IVUS in vitro before and after PTA and the findings were validated with histology. RESULTS: The sensitivity of IVUS for dissection was 74% and for media rupture 59%. The incidence of vascular damage was higher when the whole segment was analyzed rather than the target site alone. Dissections occurred at the thinnest region of the plaque, unrelated to plaque calcification. Following PTA, quantitative changes at the target site were greater compared with the overall data derived from all cross-sections. The increase in lumen area was caused solely by an increase in vessel area. CONCLUSIONS: IVUS is sensitive in detecting dissections, which occurred irrespective of calcification at the thinnest region of the plaque. The increase in lumen area after PTA was caused by stretching of the vessel.     

The relation between de novo atherosclerosis remodeling and angioplasty-induced remodeling in an atherosclerotic Yucatan micropig model

Geometric remodeling in de novo atherosclerosis and in restenosis after balloon angioplasty constitutes a change in total arterial circumference that, together with plaque growth or neointima formation, determines the lumen of the artery. The heterogeneous nature of arterial obstructions raises the question of whether early and late outcomes (restenosis) of angioplasty are affected by the degree and direction of de novo atherosclerotic remodeling. This study was designed to assess the relationship between atherosclerotic remodeling and the degree and mechanism of restenosis after balloon angioplasty. Atherosclerosis was induced in 27 peripheral arteries of 18 Yucatan micropigs by a combination of denudation and atherogenic diet. Balloon angioplasty was performed, with serial intravascular ultrasound and quantitative angiography before and after intervention and at 42 days' follow-up. We used the relative media-bounded area (MBA), defined as the MBA of the treated site divided by the MBA of the reference, before angioplasty as a measure of remodeling in de novo atherosclerosis and late MBA loss as a measure of remodeling after balloon angioplasty. Relative MBA before angioplasty was not correlated with angiographic and echographic acute gain after balloon angioplasty (r=.22, P=.28 and r=.14, P=.48) or with late lumen loss (r=-.05, P=.81 and r=.19, P=.33). No correlation was found between relative MBA and late MBA loss (r=.14 and P=.48). In the atherosclerotic Yucatan micropig, remodeling during de novo atherosclerosis has no relevance for acute gain and late lumen loss after balloon angioplasty. Both the direction and the extent of remodeling after balloon angioplasty are not related to the direction and extent of remodeling during de novo atherosclerosis.     

Coronary artery restenosis after balloon angioplasty in humans is associated with circumferential coronary constriction

Therapies that inhibit intimal hyperplasia do not prevent restenosis after coronary artery balloon angioplasty, suggesting that additional mechanisms may be responsible for restenosis in humans. Using an intravascular ultrasound (Hewlett-Packard Sonos Intravascular Imaging System). 3.5F, 30-MHz (Boston Scientific) monorail imaging catheter, we studied 17 patients with clinical and angiographic restenosis at an average (mean +/- SD) of 7 +/- 6 months after balloon angioplasty (13 men age, 71 +/- 10 years; 12 left anterior descending coronary arteries, 4 right coronary arteries, and 1 left circumflex coronary artery) The lumen area (L.A), vessel wall area (VWA), and total cross-sectional area (CSA) within the external elastic lamina were measured at the restenosis site and at proximal and distal reference sites, which were defined as adjacent segments with the least amount of plaque. Consistent with coronary angiography findings, decreased LA at the restenotic site was detected in all 17 patients. The unique finding was that total CSA at the restenotic site was significantly decreased compared with both proximal and distal reference sites (10.1 +/- 2.4 versus 14.8 +/- 3.2 mm2 and 10.1 +/- 2.4 versus 13.8 +/- 3.1 mm2, respectively, P < .001), whereas VWA (intima plus media) was slightly increased at the angioplasty site compared with both proximal and distal reference sites (8.0 +/- 2.3 versus 7.6 +/- 2.3 mm2 and 8.0 +/- 2.3 versus 6.7 +/- 2.3 mm2, respectively, P = NS). Eighty-three percent of the loss in LA at the restenotic site was due to constriction of the total CSA, while the increase in VWA at the restenotic site accounted for only a 17% loss in LA. We then compared these results with the morphology of coronary artery segments in 14 patients without restenosis. These coronary artery segments had been previously treated with balloon angioplasty (7 +/- 5 months). Unlike that in restenotic lesions, the total CSA within the external elastic lamina at the sites of previous angioplasty was similar to that in distal and proximal reference sites (P = NS). Significant and consistent reduction in arterial CSA, with a minor increase in VWA, characterizes human coronary lesions that cause angiographic restenosis. These data suggest that in humans, "recoil" and/or vascular contraction with healing in response to balloon injury is a major contributor to restenosis after balloon angioplasty.     

Propofol preserves the viability of isolated rat hepatocyte suspensions under an oxidant stress

OBJECTIVES: This study evaluated the long-term impact of endoluminal low power red laser light (LPRLL) on restenosis in an atherosclerotic rabbit model. BACKGROUND: Despite widespread application of balloon angioplasty for treatment of coronary artery disease, restenosis limits its clinical benefits. Restenosis is a complex process and may be partly attributed to the inability of the vascular endothelium to regenerate and cover the denuded area at the site of arterial injury. We previously demonstrated that LPRLL stimulates endothelial cell proliferation in vitro and contributes to rapid endothelial regeneration after balloon injury in nonatherosclerotic rabbits. METHODS: Rabbit abdominal aortas (n = 12) were treated in separate zones with balloon dilation and balloon dilation plus laser illumination. Endoluminal laser therapy was performed using a laser-balloon catheter delivering a single dose of 10 mW for 3 min from a helium-neon laser (632 nm). Angiography was performed before and after treatment and was repeated 8 weeks before harvesting the aortas. RESULTS: Quantitative angiographic analysis demonstrated no differences in the minimal lumen diameter (MLD) between the two zones before treatment; an increase in the MLD in both zones after balloon angioplasty and a significant versus slight reduction of the MLD in the balloon treatment versus balloon plus laser zones at 8 weeks. Histologic examination showed a very high level of myointimal hyperplasia in the balloon treatment zones but a minimal level in the LPRLL-treated zones. Morphometric analysis revealed a statistically significant difference in the lumen area, intimal area and intima/media ratio between the balloon versus balloon plus laser treatment sites. CONCLUSIONS: Our experimental data indicate that endoluminal irradiation with LPRLL prevents restenosis after balloon angioplasty in an atherosclerotic rabbit model.     

Mechanisms of luminal enlargement and quantification of vessel wall trauma following balloon coronary angioplasty and directional atherectomy

OBJECTIVES: The purpose of this study was to assess the dual action of lumen enlargement and vessel wall damage following either balloon angioplasty or directional atherectomy, using intracoronary ultrasound, and angioscopy. BACKGROUND: Differences in the mechanisms of action of balloon angioplasty and directional atherectomy may have a significant bearing on the immediate outcome and the restenosis rate at 6 months. METHODS: A total of 36 patients were studied before and after either balloon angioplasty (n = 18) or directional atherectomy (n = 18). Ultrasound measurements included changes in lumen area, external elastic membrane area and plaque burden. In addition, the presence and extent of dissections were assessed to derive a damage score. Angioscopic assessment of the dilated or atherectomized stenotic lesions was translated into semi-quantitative dissection, thrombus and haemorrhage scores. RESULTS: Atherectomy patients had a larger angiographic vessel size compared with the angioplasty group (3.55 +/- 0.46 mm vs 3.00 +/- 0.64 mm, P < 0.05); however, minimal lumen diameter (1.18 +/- 0.96 mm vs 0.85 +/- 0.49 mm) and plaque burden (17.04 +/- 3.69 vs 15.23 +/- 4.92 mm2) measurements did not differ significantly. As a result of plaque reduction, atherectomy produced a larger increase in luminal area than the angioplasty group (5.80 +/- 1.78 mm2 vs 2.44 +/- 1.36 mm2, P < 0.0001). Lumen increase after angioplasty was the result of 'plaque compression' (50%) and wall stretching (50%). Additionally, in both groups there was indirect angioscopic evidence of thrombus 'microembolization' as an adjunctive mechanism of lumen enlargement. Angioscopy identified big flaps in six and small intimal flaps in 11 of the atherectomized patients as compared with five and 12 patients in the angioplasty group. Changes in thrombus score following both coronary interventions were identical (0.72 +/- 3.42 points atherectomy vs -0.38 +/- 3.27 points balloon angioplasty, ns). CONCLUSIONS: Lumen enlargement after directional atherectomy is mainly achieved by plaque removal (87%), whereas balloon dilation is the result of vessel wall stretching (50%) and plaque reduction (50%). Despite the fact that the luminal gain achieved by directional atherectomy is twice that achieved with balloon angioplasty, the extent of trauma induced by both techniques seems to be similar.     

The atherosclerotic Yucatan animal model to study the arterial response after balloon angioplasty: the natural history of remodeling

OBJECTIVE: Remodeling in de novo atherosclerosis and in restenosis after balloon angioplasty constitutes a change in total arterial circumference which, together with plaque growth or neointimal formation, determines the lumen of the artery. To better understand the fundamental biology of neointimal formation, remodeling and their interaction, animal studies are needed. In this study, we described in detail the methodology used and the natural history of neointimal formation and remodeling after balloon angioplasty in atherosclerotic Yucatan micropigs. METHODS AND RESULTS: Atherosclerosis was induced in 60 peripheral arteries of sixteen Yucatan micropigs by a combination of denudation and atherogenic diet. Balloon angioplasty was performed in 38 arteries, with serial intravascular ultrasound (IVUS) and quantitative angiography before and after intervention and at 2, 4, 7, 14 or 42 days follow-up. Remodeling, expressed as late media-bounded area (MBA) loss, increased progressively over time. At 42 days, late MBA loss after balloon angioplasty was significantly different compared to late MBA loss in control arteries, 2.2 +/- 1.0 versus -0.3 +/- 1.1 mm2 and p = 0.02. Late lumen loss increased over time and was highest at 42 days after balloon angioplasty (2.8 +/- 0.7 mm2). The contribution of neointimal formation to late lumen loss decreased over time and the contribution of late MBA loss to late lumen increased over time and was highest at 42 days (78%). Medial necrosis was 48% at two days after balloon angioplasty and the repopulation of the media was almost completed at seven days. CONCLUSION: Remodeling following balloon angioplasty has an early onset and progresses with neointimal formation to cause restenosis over the standard 42-day time course for Yucatan micropigs. This correlates to six months renarrowing in humans. In this model, atherosclerosis and the natural history of restenosis, both with respect to neointimal formation and remodeling, resemble the human disease quite closely.     

Internal mammary artery graft angioplasty: acute and long-term outcome

Secondary to the low attrition rate of internal mammary artery grafts, limited data are available on the clinical and angiographic outcome of patients who have undergone balloon angioplasty of an internal mammary artery stenosis. This study examined a consecutive series of 68 patients who underwent balloon angioplasty of an internal mammary artery graft over a 9-year period. Procedural success was achieved in 60 of 68 (88%) patients. The primary reason for procedural failure was extreme vessel tortuosity. There were no major in-hospital complications. Angiographic follow-up was obtained in 78% of the patients with an angiographic restenosis rate of 19%. The overall event-free survival in patients with an initially successful procedure was 92%. In conclusion, internal mammary artery balloon angioplasty has both an excellent initial success rate as well as a low incidence of restenosis and repeat target lesion revascularization.     

Lower-extremity arterial endovascular stenting

Intraluminal arterial stenting for the management of arterial occlusive disease of the lower extremities has evolved over the years. Most stents are used to correct inadequacies of PTA or to correct a PTA complication. These include (1) restenosis within 90 days of PTA, (2) chronic iliac occlusion, (3) acute occlusions during PTA, (4) a significant residual gradient following PTA, (5) dissections longer than the angioplasty site, and (6) a 30% or greater residual stenosis after PTA. Both the Palmaz stent and the Wallstent have performed well in the iliac artery system. Their use in the femoropopliteal system has not been as successful and should be reserved for selected cases. Long-term anticoagulation is generally required for femoropopliteal stent patency. Placement in the lower superficial femoral or popliteal artery is best avoided. Re-angioplasty or additional stenting may be used to prolong patency, although with the risk of a second intervention. Progression of arteriosclerosis is a factor to consider when choosing an endoluminal treatment versus standard bypass.     

Anesthetic implications for implantation of a left ventricular assist device: a case study

Restenosis after coronary angioplasty is a major limitation of an otherwise highly effective and safe procedure for the treatment of atherosclerotic coronary artery disease. Although the advent of coronary stenting has reduced restenosis rates for selected patients, an overall restenosis rate of 20% to 25% remains. Despite numerous trials, no effective pharmacologic therapy has been found. Intracoronary irradiation is a new technique proposed to prevent restenosis after angioplasty. In animal models of restenosis after balloon injury, there is marked reduction of neointimal proliferation when the injured vessel is irradiated, using a variety of radiation sources and delivery systems. Early human trials have underscored the importance of careful source calibration and dosimetry. A small, randomized, double-blind, placebo-controlled study of intracoronary irradiation to prevent recurrent restenosis recently reported striking reductions in angiographic restenosis as well as clinical event rates. A number of important issues remain unresolved, such as defining which component of the arterial wall serves as the target tissue for radiation, the minimal effective dose, the maximum tolerable dose, and user-friendly radiation delivery systems. Further studies are needed to define the safety, efficacy and the ultimate usefulness of intracoronary irradiation as an adjunct to current procedures in interventional cardiology.     

Immobilization of domestic goats (Capra hircus) using orally administered carfentanil citrate and detomidine hydrochloride

A total of 147 stents were implanted (in overlapping manner in 76% of vessels) in a single coronary artery in 59 patients (60 vessels, 97 lesions, 2.45 stents/vessel) over a period of 18 mo using high pressure stent deployment without ultrasound guidance. The indications for stenting were suboptimal percutaneous transluminal coronary angioplasty (PTCA) result (45%), primary prevention of restenosis (44%), acute closure (10%), and restenosis after plain balloon angioplasty (1%). One patient required emergency coronary artery bypass grafting (CABG) (extensive dissection), and one required early intervention with plain balloon angioplasty and intracoronary urokinase for stent thrombosis. There were no deaths. Thirteen patients had recurrence of angina within 6 mo and angiograms were performed in all. These showed intrastent restenosis in nine (all had successful repeat plain balloon angioplasty), development of new disease in other vessels along with restenosis close to the stent in the target vessel in one (underwent elective CABG) and normal angiograms with widely patent stents in three. Forty-five patients (77%) remained free of recurrent angina and 25 of these had follow-up angiograms (56%) at a mean of 172 days, two showing restenosis. Thus, the restenosis rate per patient in the symptomatic group (angiographic follow-up in 100%) was 77% and in the asymptomatic group (angiographic follow-up in 56%) was 8%. The restenosis rate in the subgroup with bailout stenting (n = 6) was 20% (angiographic follow-up in 83%). The overall restenosis rate per patient was 32% (overall angiographic follow-up in 66%). During the 6-mo follow-up period, one patient underwent elective CABG (1.7%), one sustained a non-Q myocardial infarction (1.7%), nine had repeat PTCA to the target vessel (15.5%), and there were no deaths. The event-free survival rate was 77%. Multiple stent implantation aided by high pressure stent deployment without ultrasound guidance and with adjunctive optimal antiplatelet therapy without oral anticoagulation seems to be a useful and effective revascularisation strategy to deal with long lesions and acute dissections with a high procedural success rate. The restenosis rate is acceptable and is not appreciably high as reported in previous studies from the "warfarin era."     

Differences in restenosis propensity of devices for transluminal coronary intervention. A quantitative angiographic comparison of balloon angioplasty, directional atherectomy, stent implantation and excimer laser angioplasty. CARPORT, MERCATOR, MARCATOR, PARK, and BENESTENT Trial Groups

With the increasing clinical application of new devices for percutaneous coronary revascularization, maximization of the acute angiographic result has become widely recognized as a key factor in maintained clinical and angiographic success. What is unclear, however, is whether the specific mode of action of different devices might exert an additional independent effect on late luminal renarrowing. The purpose of this study was to investigate such a difference in the degree of provocation of luminal renarrowing (or 'restenosis propensity') by different devices, among 3660 patients, who had 4342 lesions successfully treated by balloon angioplasty (n = 3797), directional coronary atherectomy (n = 200), Palmaz-Schatz stent implantation (n = 229) or excimer laser coronary angioplasty (n = 116) and who also underwent quantitative angiographic analysis pre- and post-intervention and at 6-month follow-up. To allow valid comparisons between the groups, because of significant differences in coronary vessel size (balloon angioplasty = 2.62 +/- 0.55 mm, directional coronary atherectomy = 3.28 +/- 0.62 mm, excimer laser coronary angioplasty = 2.51 +/- 0.47 mm, Palmaz-Schatz = 3.01 +/- 0.44 mm; P < 0.0001), the comparative measurements of interest selected were the 'relative loss' in luminal diameter (RLoss = loss/vessel size) to denote the restenosis process, and the 'relative lumen at follow-up' (RLfup = minimal luminal diameter at follow up/vessel size) to represent the angiographic outcome. For consistency, lesion severity pre-intervention was represented by the 'relative lumen pre' (RLpre = minimal luminal diameter pre/vessel size) and the luminal increase at intervention was measured as 'relative gain' (relative gain = gain/ vessel size). Differences in restenosis propensity between devices was evaluated by univariate and multivariate analysis. Multivariate models were constructed to determine relative loss and relative lumen at follow-up, taking account of relative lumen pre-intervention, lesion location, relative gain, vessel size and the device used. In addition, model-estimated relative loss and relative lumen at follow-up at given relative lumen pre-intervention relative gain and vessel size, were compared among the four groups. Significant differences were detected among the groups both with respect to these estimates, as well as in the degree of influence of progressively increasing relative gain, on the extent of renarrowing (relative loss) and angiographic outcome (relative lumen at follow-up), particularly at higher levels of luminal increase (relative gain). Specifically, lesions treated by balloon angioplasty or Palmaz-Schatz stent implantation (the predominantly 'dilating' interventions) were associated with more favourable angiographic profiles than directional atherectomy or excimer laser (the mainly 'debulking' interventions). Significant effects of lesion severity and location, as well as the well known influence of luminal increase on both luminal renarrowing and late angiographic outcome were also noted. These findings indicate that propensity to restenosis after apparently successful intervention is influenced not only by the degree of luminal enlargement achieved at intervention, but by the device used to achieve it. In view of the clinical implications of such findings, further evaluation in larger randomized patient populations is warranted.     

The influence of coffee with milk and tea with milk on the bioavailability of tetracycline

BACKGROUND: At the initial stages of percutaneous transluminal coronary angioplasty (PTCA), several studies reported on the feasibility of coronary artery incision and dilatation leading to the extension of the PTCA technique. HYPOTHESIS: This study was designed to determine the immediate and chronic results of cutting balloon (CB) angioplasty. METHODS: This procedure was performed on 127 lesions in 110 patients (male 83%, age 61.8 +/- 9.3 years). RESULTS: The overall procedural success rates for the CB were 93.7% (119 lesions) and 92.7% (102 patients), while solitary CB without pre- and/or postdilatation was 76.4% (91 lesions). There was one major in-hospital complication (Q-wave myocardial infarction, 0.9%), but there were no deaths or emergency coronary artery bypass graftings. Significant angiographic dissections (> or = grade C) occurred in four patients, and coronary perforation occurred in one. The successfully treated CB group (95 lesions) was matched with the successful conventional angioplasty group (PTCA group) for chronic result assessment in regard to reference vessel size and lesion characteristics. In the CB group, postprocedural minimal luminal diameters were significantly larger and the percentage of stenosis at the stenotic site was significantly lower compared with the PTCA group. Restenosis occurred in 22 lesions (23.1%). This showed a significantly lower restenosis rate compared with the PTCA group (42.1%). In addition, the restenosis rate of the CB without inclusion of the pre- and/or postdilatation-treated lesions was 19.7%. CONCLUSIONS: (1) Cutting balloon angioplasty procedures can be performed with high success rates with few major inhospital events. (2) The restenosis rate in the CB group was significantly lower compared with the PTCA group.     

Cytochrome P450 2E1 mRNA in the rat prostate: detection and quantitation by competitive reverse transcription and polymerase chain reaction

Conventional balloon angioplasty treatment of aorto-ostial stenoses in native coronary arteries and saphenous vein grafts is associated with a low primary success rate, a high complication rate and a high incidence of restenosis. The short-term outcome of Palmaz-Schatz stent implantation in aorto-ostial lesions was compared with that of balloon angioplasty. Thirteen patients underwent stent implantation for 13 de novo lesions (four in the left main coronary trunk, two in the right coronary artery, seven in the vein graft) between January 1994 and December 1995. Fourteen patients underwent balloon angioplasty for 14 de novo lesions (five in the left main coronary trunk, four in the right coronary artery, five in the vein graft between January 1986 and April 1992. Both groups had similar clinical characteristics. Initial success was obtained in all patients in the stent group, compared with 71% of the balloon angioplasty group. Insufficient dilation was the main cause for such failure in the balloon angioplasty group. Baseline reference diameters were similar (3.40 +/- 0.65 mm in the stent group vs 3.36 +/- 0.42 mm in the balloon angioplasty group) and there was no difference in baseline minimal luminal diameter (1.41 +/- 0.74 vs 1.08 +/- 0.56 mm). Minimal luminal diameter was significantly greater in the stent group than in the balloon angioplasty group at both post-procedure and follow-up examinations (post: 3.36 +/- 0.58 vs 2.69 +/- 0.45 mm, p < 0.01; follow-up: 2.33 +/- 0.96 vs 1.52 +/- 0.68 mm, p < 0.05). There was no subacute occlusion in either group. The overall angiographic restenosis rate (> 50% stenosis) was lower in the stent group (17%) than in the balloon angioplasty group: the restenosis rates of native lesions were 0% in the stent group and 40% in the balloon angioplasty group; those of saphenous vein graft lesions were 33% in the stent group and 50% in the balloon angioplasty group. Although the number of patients was limited, these results suggest that Palmaz-Schatz stent implantation may be a safe and effective strategy for treating aorto-ostial lesions in both native coronary arteries and saphenous vein grafts.     

An explanation for discrepancy between angiographic and intravascular ultrasound measurements after percutaneous transluminal coronary angioplasty

OBJECTIVES: This study attempted to determine why there is a discrepancy between angiographic and intravascular ultrasound measurements after coronary balloon angioplasty. BACKGROUND: Previous studies have shown a poor correlation between angiographic and intravascular ultrasound measurements after percutaneous coronary balloon angioplasty. METHODS: After successful balloon angioplasty, 91 lesions in 84 patients were studied by intravascular ultrasound. Plaque morphology on intravascular ultrasound was classified as demonstrating a superficial injury if there was either no fracture or only a small tear that did not extend to the media versus a deep injury defined as the presence of a plaque fracture that reached the media. Measurements of minimal lumen diameter were compared between angiography and intravascular ultrasound. RESULTS: On ultrasound imaging, a superficial injury pattern was observed in 44 lesions, whereas a deep injury was seen in 47 lesions. There were no statistical differences at baseline in patient or lesion characteristics. In the superficial injury group there was a significant correlation between angiography and intravascular ultrasound for minimal lumen diameter (r = 0.67) and lumen cross-sectional area (r = 0.69). In the deep injury group there was a poor correlation for minimal lumen diameter (r = 0.05) and lumen cross-sectional area (r = 0.28). After balloon angioplasty, the angiographic appearance showed a normal contour in 34%, the presence of dissection in 38% or a hazy appearance in 23%. On ultrasound imaging after angioplasty, the superficial injury group comprised 65% of lesions with a normal angiographic appearance and 67% of lesions with a hazy appearance, whereas 77% of lesions with an angiographic diagnosis of dissection were in the deep injury group by ultrasound (p = 0.0005). CONCLUSIONS: These observations suggest that the discrepancies between angiographic and ultrasound measurements are due to differences in plaque morphology created by balloon dilation. Superficial injuries demonstrate similar results by angiography or ultrasound, whereas a deep injury to the plaque produces a difference in measurements between angiography and ultrasound. When angiography reveals a dissection, there is a high probability that intravascular ultrasound will demonstrate a plaque fracture extending to the media.     

Doppler sonography diagnosis of restenosis after percutaneous transluminal angioplasty: sensitivity and specificity of the pedal-brachial index in relation to changes in absolute arterial blood pressure

INTRODUCTION: Percutaneous transluminal angioplasty (PTA) is accepted for the treatment of patients with severe, disabling claudication who fail conservative management and also for patients with limb threatening ischaemia [1-5, 18, 20]. The development of neointimal hyperplasia (predominantly during the first 6-12 months after PTA), and the progression of the underlying atherosclerotic disease (thereafter), are the reasons of restenosis and reocclusion [1-4, 6]. More than 50% of occurring restenoses are primarily oligo/asymptomatic [1-4, 6-10, 25, 26]. Follow-up visits are aimed at detecting significant restenoses, before reocclusion occurs, so that timely reintervention is possible. In asymptomatic patients in whom reintervention is not necessary, repeated angiography is not justifiable. Non-invasive alternatives include Duplex scanning or the assessment of simple peripheral haemodynamic variables such as ankle systolic pressures and the ankle/brachial pressure index (ABI). The aim of this study was: (1) To determine the sensitivity and specificity of post PTA changes in the ABI, and changes in the absolute ankle pressure to detect restenoses after femoropopliteal PTA (as a gold standard, Duplex scanning, with its reported high sensitivity, specificity and accuracy for detecting restenosis was chosen [9, 25]. (2) For both methods, to evaluate the criteria (minimal magnitude of change-cut off points) necessary to detect restenosis with reasonable reliability. (3) To compare the diagnostic value of changes in ABI to changes in absolute ankle pressure, and to determine the method of preference for detection of post-PTA restenosis. MATERIAL AND METHODS: The study included 171 consecutive patients with peripheral arterial occlusive disease, Fontaine stage II or stage III, selected for femoro-popliteal PTA. All pts presented with single or multiple arterial stenoses or occlusions not exceeding 10 cm of length within the femoro-popliteal segment. At least one lower leg artery had to be patent. Only pts in whom PTA was successful (maximum residual lesion within the dilated segment showed < or = 30% diameter reduction (DR)) were accepted for a 12-month follow-up. After PTA all patients were prescribed a platelet aggregation inhibitor. The investigational scheme included the following procedures: 1. Duplex scanning of the entire lower leg vascular tree before PTA, within 7 days after PTA as well as at 4 weeks and at 12 months. 2. Scoring of Duplex results using the Bollinger angiography score system [11] which distinguishes the pelvic segment, a proximal and a distal superficial femoral segment, the popliteal artery including the popliteal trifurcation and the proximal 1/3 of the lower leg arteries. The score system allows the differentiation of single and multiple plaque (< or = 25% DR), single or multiple stenoses (< or = 50% and < or = 50% DR) involving less or more than 50% of the segment under investigation as well as short (< 50% of segment length) and long (> or = 50% of segment length) vascular occlusions. 3. The assessment of the resting ankle systolic pressures (dorsalis pedis artery, posterior tibial artery) of the reference leg, pre PTA, at 4 weeks, and 3, 6, 9 and 12 months using a 8 Mhz CW Doppler device (Parks 908) with the patient in the supine position and after a resting period of > or = 30 minutes. 4. The calculation of the ankle/brachial pressure index (ABI) as the ratio of the higher systolic pressure value from either the posterior tibial or the dorsalis pedis artery divided by the higher value of the two (bilateral) systolic brachial pressures. 5. A full physical examination including a pulse status, vascular auscultation as well as the assessment of the clinical symptomatology pre PTA, at 4 weeks as well as at 6 and 12 months. The following findings were suggestive of restenosis/reocclusion of the dilated segment. 1. Reoccurrence of a stenosis < or = 50% DR within the dilated segment and/or its inflow or outflo     

Does stent placement improve the results of ineffective or complicated iliac artery angioplasty?

OBJECTIVE: This study was undertaken to determine the results and complications of stents placed for initially unsuccessful or complicated iliac percutaneous transluminal angioplasty (PTA), the effect of location (external iliac or common iliac) on outcome, and the influence of superficial femoral artery patency on benefit. DESIGN: From 1992 through 1997, 350 patients underwent iliac artery PTA at the authors' institutions. Of this group, 88 patients (88 arteries) had one or more stents placed after PTA (140 stents in total) for residual stenosis or pressure gradient (63 patients), iliac dissection (12 patients), long-segment occlusion (10 patients), or recurrent stenosis (3 patients). Thirty patients required the placement of more than one stent. The indications for PTA in these 88 patients were claudication (48 patients) and limb-threatening ischemia (40 patients). Forty-seven patients had stents placed in the common iliac, 29 patients had stents placed in the external iliac, and 12 patients had stents placed in both. Seventy-one arteries (81%) were stenotic, and 17 (19%) were occluded before PTA. Sixty-six arteries were treated by interventional radiologists, 15 by a vascular surgeon, and 7 jointly. MAIN OUTCOME MEASURE: Criteria for success included (1) increase of at least one clinical category of chronic limb ischemia from baseline or satisfactory wound healing, (2) maintenance of an ankle/brachial index increase of more than 0.10 above the preprocedure index, and (3) residual angiographic stenosis less than 25% and, for patients with pressure gradient measurements, a residual gradient less than 10 mm Hg. RESULTS: Stent placement was accomplished in all 88 patients with 16 (18%) major complications. Mean follow-up was 17 months (range, 3 to 48 months). By life-table analysis, success was 75% at 1 year, 62% at 2 years, and 57% at 3 years. No cardiovascular risk factor or independent variable was statistically significant in predicting success. There was no difference in success rates for common iliac or external iliac lesions. Superficial femoral artery patency did not correlate with outcome. CONCLUSIONS: Although stents can eliminate residual lesions and arterial dissection, these patients are likely to require adjuvant or subsequent procedures to attain clinical success. By controlling the PTA complication and treating the emergent problem, stents may allow for subsequent elective intervention.     

Percutaneous transluminal angioplasty in atherosclerosis

Percutaneous transluminal balloon angioplasty has achieved a dominant role in the interventional treatments of atherosclerotic peripheral, renal, and coronary artery disease. Improved operator's technique and equipment design have increased the primary success rate. Despite improved success rate and safety, acute closure, late restenosis and difficulty in treating chronic total occlusions or diffuse lesions remain as serious limitations of this procedure. To overcome these limitations of balloon angioplasty, new devices such as stenting, atherectomy or laser ablation have been developed. Although there are many problems for each device, these techniques appear to reduce the limitations in angioplasty.     

Newly developed blocking balloon catheter for PTA of internal carotid artery

We have developed a new blocking balloon system for percutaneous transluminal angioplasty (PTA) of the internal carotid artery (ICA). A latex balloon (BALT) is attached on the top of a Superselector infusion-type catheter (TORAY) which is used as a blocking balloon catheter. It can be navigated into the distal part of the ICA under torque control as well as flow control by withdrawing the core wire. Our PTA procedure is as follows, 1) insert the sheath catheter 8-9 F in size, 2) insert the PTA balloon catheter (Accent balloon, Cook) with a blocking balloon catheter through the sheath catheter, 3) navigate the blocking balloon into the distal part of the ICA, 4) introduce the PTA balloon to the stenotic portion after occlusion of the distal ICA by the blocking balloon, 5) PTA, 6) wash the lumen of the ICA with saline, 7) deflate the blocking balloon and withdraw the system. We performed PTA for 5 ICA lesions in 4 cases and got successful dilatations for all of them without complications. Our blocking balloon system is useful for performing the PTA of the ICA safely.     

Bovine endometrial retinol-binding protein secretion, messenger ribonucleic acid expression, and cellular localization during the estrous cycle and early pregnancy

OBJECTIVES: We assessed the safety and efficacy of stent placement in patients with poorly controlled hypertension and renal artery stenoses, which are difficult to treat with balloon angioplasty alone. BACKGROUND: Preliminary experience with stent placement suggests improved results over balloon angioplasty alone in patients with atherosclerotic renal artery stenosis. METHODS: Balloon-expandable stents were placed in 100 consecutive patients (133 renal arteries) with hypertension and renal artery stenosis. Sixty-seven of the patients had unilateral renal artery stenosis treated and 33 had bilateral renal artery stenoses treated with stents placed in both renal arteries. RESULTS: Angiographic success, as determined by quantitative angiography, was obtained in 132 (99%) of 133 lesions. Early clinical success was achieved in 76% of the patients. Six months after stent placement, the systolic blood pressure was reduced from 173 +/- 25 to 147 +/- 23 mm Hg (p < 0.001); the diastolic pressure from 88 +/- 17 to 76 +/- 12 mm Hg (p < 0.001); and the mean number of antihypertensive medications per patient from 2.6 +/- 1 to 2.0 +/- 0.9 (p < 0.001). Angiographic follow-up at a mean of 8.7 +/- 5.0 months in 67 patients revealed restenosis (>50% diameter narrowing) in 15 (19%) of 80 stented vessels. CONCLUSIONS: Renal artery stenting is an effective treatment for renovascular hypertension, with a low angiographic restenosis rate. Stent placement appears to be a very attractive therapy in patients with lesions difficult to treat with balloon angioplasty such as renal aorto-ostial lesions and restenotic lesions, as well as after a suboptimal balloon angioplasty result.