Excimer laser-facilitated angioplasty for undilatable coronary narrowings

Calcified and fibrotic coronary artery lesions cannot always be dilated with conventional balloon angioplasty even at high pressures. This study examines the success of excimer laser facilitated angioplasty in 38 lesions in 37 patients with lesions that failed balloon angioplasty alone.     

Coronary angioplasty in octogenarians

Coronary balloon angioplasty was performed on 33 lesions during 28 procedures in 23 octogenarians (median age 83, range 80 to 87 years) between January 1989 and December 1991. 96% of the patients had grade III-IV angina pectoris. The median left ventricular ejection fraction was 64% (range: 38-85%). Single vessel coronary artery disease was present in 43% and multivessel coronary artery disease in 57%. Angioplasty was performed on 1 vessel in 85% of the procedures and on 2 vessels in 15%. Primary angiographic success was 97% for 33 attempted lesions with one failure to recanalize an old occlusion. One patient underwent emergency intracoronary stent implantation after failed angioplasty. None underwent emergency coronary bypass surgery. One patient (4%) had a myocardial infarction and 2 patients (7%) died during hospitalization, the first because of abrupt vessel closure during angioplasty, the second due to acute retroperitoneal bleeding on the 8th day post-angioplasty while fully anticoagulated for an intracoronary stent. Follow-up (median 17, range 8 to 39 months) was obtained for all patients. Out of the 21 patients with primary angioplastic success, 3 (14%) had died (1 cardiac and 2 non-cardiac). At 1 year actuarial survival was 86%, and survival free from myocardial infarction or coronary bypass surgery was 81%. Further angioplasty for either restenosis or another lesion was performed in 5 patients (24%). These results confirm that coronary angioplasty is an effective means of controlling anginal symptoms in a selected group of severely symptomatic octogenarians. However, when complications do occur they are linked to a significant mortality rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Restenosis rates in diabetic patients: a comparison of coronary stenting and balloon angioplasty in native coronary vessels

BACKGROUND: Diabetes is a major risk factor for restenosis after coronary balloon angioplasty. Recent studies have shown that coronary stenting significantly reduces restenosis compared with balloon angioplasty alone. However, limited information is available on the effect of coronary stenting in diabetic patients. METHODS AND RESULTS: We designed this study to analyze the effect of diabetes on restenosis in patients treated with either balloon angioplasty or coronary stenting who were enrolled in a 6-month angiographic follow-up program. Three hundred consecutive patients, 19% of whom were diabetics, who underwent coronary stent implantation during a single-vessel procedure on native coronary vessels and who had 6-month angiographic follow-up constituted the study group (stent group). Three hundred consecutive patients who underwent 6-month angiographic follow-up after single-vessel conventional balloon angioplasty served as control patients (balloon group). Preprocedural, postprocedural, and follow-up angiograms were analyzed with quantitative angiography. In the balloon group, the restenosis rate was almost twofold higher in diabetic than in nondiabetic patients (63% versus 36%; P=.0002) owing to both a greater late loss (0.79+/-0.70 versus 0.41+/-0.61 mm, respectively; P<.0001) and a higher rate of late vessel occlusion (14% versus 3%, respectively; P<.001). In the stent group, restenosis rates were similar in diabetics and nondiabetics (25% versus 27%, respectively). Furthermore, in the stent group, late loss (0.77+/-0.65 versus 0.79+/-0.57 mm, respectively) and the rate of late vessel occlusion (2% versus 1%, respectively) did not differ significantly between diabetic and nondiabetic patients. CONCLUSIONS: Although diabetics have increased rates of restenosis and late vessel occlusion after simple balloon angioplasty, they have the same improved outcome with coronary stenting that has been documented in nondiabetic patients.     

Excimer laser angioplasty versus balloon angioplasty in functional and total coronary occlusions

Registries of excimer laser coronary angioplasty have reported good results in the treatment of complex coronary artery disease, including total or subtotal coronary occlusions. One hundred three patients (103 lesions) with a functional or total coronary occlusion were included in a randomized trial (Amsterdam-Rotterdam [AMRO] trial, total of 308 patients), 49 patients were allocated to laser angioplasty and 54 patients to balloon angioplasty. The primary clinical end points were death, myocardial infarction, coronary bypass surgery, or repeated coronary angioplasty of the randomized segment during a 6-month follow-up period. The primary angiographic end point was the minimal lumen diameter at follow-up in relation to the baseline value (net gain), as determined by an automated contour-detection algorithm. Laser angioplasty was followed by balloon angioplasty in all procedures. The angiographic success rate was 65% in patients treated with excimer laser-assisted balloon angioplasty compared with 61% in patients treated with balloon angioplasty alone. No deaths occurred. There were no significant differences between the laser angioplasty group and the balloon angioplasty group in the incidence of myocardial infarctions (1 patient vs 3, respectively, p = 0.36), coronary bypass surgery (4 patients vs 2, respectively, p = 0.34), repeat angioplasty (10 patients vs 8, respectively, p = 0.46) or primary clinical end point (15 patients vs 12, respectively, p = 0.34). The net gain in minimal lumen diameter and restenosis rate (>50% diameter stenosis at follow-up) were 0.81 +/- 0.74 mm and 66.7%, respectively, in patients treated with laser angioplasty compared with 1.04 +/- 0.68 mm and 48.5%, respectively, in patients treated with balloon angioplasty (p = 0.59 and p = 0.15, respectively). Excimer laser-assisted balloon angioplasty demonstrated no benefit over balloon angioplasty with respect to initial and long-term clinical and angiographic outcome in the treatment of patients with functional or total coronary occlusions of >10 mm in length.     

Are directional coronary atherectomy and Palmaz-Schatz stent more efficacious than conventional balloon angioplasty for treating de novo coronary artery lesions?

It is unclear whether new devices such as directional coronary atherectomy (DCA) or Palmaz-Schatz stent implantation improve long-term outcomes compared with conventional balloon angioplasty in patients with stable angina and de novo coronary artery lesions of type A or type B except for complete occlusive lesions investigated by the American College of Cardiology/American Heart Association task force on percutaneous transluminal coronary angioplasty. A total of 146 patients with stable angina and simple lesions were assigned to either conventional balloon angioplasty (62 patients), DCA (50 patients), or Palmaz-Schatz implantation (34 patients). The acute results and late outcomes were assessed by coronary angiography. The results of the three procedures were similar with respect to procedural success and complications. Patients who underwent stenting or DCA had a larger immediate increase in the diameter of the lumen and a larger luminal diameter immediately after the procedure than those who underwent balloon angioplasty. At six months follow-up, the patients treated by stenting continued to have a larger luminal diameter and a lower rate of restenosis than those treated with balloon angioplasty (2.30 +/- 0.66 vs 1.85 +/- 0.83 mm, p < 0.005; 5.9% vs 29%, p < 0.05) and DCA (2.30 +/- 0.66 vs 1.90 +/- 0.96 mm, p < 0.05; 5.9% vs 24%, NS). The patients treated with balloon angioplasty had a smaller late loss than those treated with DCA or Palmaz-Schatz stent. The patients treated with DCA had a larger loss index than those treated with balloon angioplasty or Palmaz-Schatz stent. Stenting was a significant factor in decreasing the rate of restenosis by logistic regression analysis, compared with balloon angioplasty. The angiographic outcomes were better in patients who received a stent than in those who received other treatments. This study suggests that even lesions stable for treatment by balloon angioplasty and DCA can also be treated with Palmaz-Schatz stents.     

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.     

Coronary-artery stenting compared with balloon angioplasty for restenosis after initial balloon angioplasty. Restenosis Stent Study Group

BACKGROUND: Intracoronary stenting reduces the rate of restenosis after angioplasty in patients with new coronary lesions. We conducted a prospective, randomized, multicenter study to determine whether intracoronary stenting, as compared with standard balloon angioplasty, reduces the recurrence of luminal narrowing in restenotic lesions. METHODS: A total of 383 patients who had undergone at least one balloon angioplasty and who had clinical and angiographic evidence of restenosis after the procedure were randomly assigned to undergo standard balloon angioplasty (192 patients) or intracoronary stenting with a Palmaz-Schatz stent (191 patients). The primary end point was angiographic evidence of restenosis (defined as stenosis of more than 50 percent of the luminal diameter) at six months. The secondary end points were death, Q-wave myocardial infarction, bypass surgery, and revascularization of the target vessel. RESULTS: The rate of restenosis was significantly higher in the angioplasty group than in the stent group (32 percent as compared with 18 percent, P= 0.03). Revascularization of the target vessel at six months was required in 27 percent of the angioplasty group but in only 10 percent of the stent group (P=0.001). This difference resulted from a smaller mean (+/-SD) minimal luminal diameter in the angioplasty group (1.85+/-0.56 mm) than in the stent group (2.04+/-0.66 mm), with a mean difference of 0.19 mm (P=0.01) at follow-up. Subacute thrombosis occurred in 0.6 percent of the angioplasty group and in 3.9 percent of the stent group. The rate of event-free survival at 250 days was 72 percent in the angioplasty group and 84 percent in the stent group (P=0.04). CONCLUSIONS: Elective coronary stenting was effective in the treatment of restenosis after balloon angioplasty. Stenting resulted in a lower rate of recurrent stenosis despite a higher incidence of subacute thrombosis.     

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.     

Restenosis after coronary angioplasty

Coronary angioplasty is used to treat coronary disease in many patients. Indications for angioplasty have expanded since it was first performed, mainly as a result of improvement in equipment and techniques. One problem with coronary angioplasty is the phenomenon of renarrowing of the treated coronary lesion, a process called restenosis. The events that constitute restenosis appear to be a universal response to the arterial wall injury of angioplasty. They are currently characterized as follows: platelet adhesion and aggregation on the damaged endothelium and within deep splits into the tunica media; release of platelet-derived growth factors; inflammation of the mechanically injured medial zone; transformation of smooth muscle cells of the tunica media after their activation by several of the growth-promoting substances; migration and proliferation of transformed smooth muscle cells, with secretion of copious amounts of extracellular matrix material; and, finally, termination of the growth process with regrowth of endothelium over the injured area. A decade of research work has helped identify clinical correlates of restenosis after coronary angioplasty procedures. This work is hindered by lack of a uniform angiographic definition of restenosis. In addition, much of the information has come from small studies, with incomplete follow-up and retrospective orientation. Nevertheless, some data are available. Patient-related correlates include male gender, unstable angina, diabetes, and continued smoking after angioplasty. Lesion-related correlates include multilesional and multivessel procedures, higher postangioplasty residual stenosis, proximal vessel location, location in the left anterior descending artery, location in a vein graft, long lesions, and total occlusions. The only consistent procedure-related correlate has been incorrect sizing of the angioplasty balloon to the treated artery. For the purposes of individual patient care, clinical correlates are not helpful. No group of variables has been found to be associated with complete freedom from restenosis, and no group is completely predictive of restenosis. All patients undergoing angioplasty procedures require some follow-up through subsequent months and years. Symptom status and the results of noninvasive studies have been investigated for purposes of follow-up. Symptoms are virtually useless by themselves for predicting restenosis or its absence. When symptom status is combined with exercise thallium 201 scintigraphy performed 4 to 6 months after an angioplasty procedure, the two factors are less than ideal but have a negative predictive value of more than 90%. This means that more than 90% of patients who have neither symptoms nor evidence of ischemia by thallium 201 scintigraphy will not have angiographic restenosis.(ABSTRACT TRUNCATED AT 400 WORDS)     

Restenosis and arterial remodelling after coronary angioplasty

Restenosis after coronary angioplasty (PTCA) is a complex process and is still the major problem, despite improvements in equipment and technique. Thrombus formation and intimal hyperplasia have been considered to be the main causes of the development of restenosis after primary successful angioplasty. As yet, pharmacological trials to prevent restenosis have failed to prevent it, despite the fact that the therapy has been aimed at reducing thrombus formation and intimal hyperplasia. Several new angioplasty devices have been developed. Series of observations and a few controlled trials have demonstrated restenosis rates similar to those obtained with conventional balloon angioplasty, except in the case of stent implantation, which appears to be promising. Intravascular ultrasound studies have provided new insight and a more complete understanding of the process leading to restenosis. Vascular remodeling is now considered as an important pathogenetic factor. It consists of a change in the cross-sectional vessel area and may involve an actual constriction of the artery. This may lead to lumen-narrowing and finally restenosis with minimal neointimal formation. In this review we summarise the literature on the restenosis process and the current status of the clinical trials aimed at preventing restenosis.     

Anti-atherogenicity in women does not prevent restenosis after balloon angioplasty

To test the hypothesis that anti-atherogenicity in women exerts beneficial effects to prevent restenosis formation after coronary angioplasty, we studied 493 men (988 lesions) and 81 women (159 lesions), aged 40-60 years, who had undergone successful balloon angioplasty and had follow-up angiography, 4.9 +/- 4.1 months later. We compared the extent of restenosis between men and women, and between pre- and post-menopausal women, which was assessed by a categorical definition of restenosis (more than 50% diameter stenosis at follow-up) and by percent diameter measured immediately after angioplasty and at follow-up. Hypertension was more frequent in women and a significantly lower percentage of women smoked. In women, the levels of total cholesterol and low-density lipoprotein cholesterol were higher. The location of dilated lesions, frequency of angioplasty for lesions with chronic total occlusion, and frequency of emergency angioplasty in patients with unstable angina or acute myocardial infarction were similar in men and women. Restenosis formation, estimated by the categorical definition or percent diameter, did not differ between men and women, or between pre- and post-menopausal women. Menopausal status or sex was not an independent predictor of restenosis by multivariate analysis. Thus, the benefit of anti-atherogenicity in women does not play an important role in preventing restenosis after coronary angioplasty.     

Ultrasound coronary angioplasty: state of the art and new clinical aspects

Therapeutic ultrasound was shown to ablate thrombi and to disrupt atherosclerotic plaques in vitro and recently to recanalize occluded coronary arteries in acute myocardial infarction (AMI). The goal of this article is to update collective experience and to weigh the promising and unresolved aspects of this newly developed technology and its clinical results. As therapeutic ultrasound was for long known a synonym for lithotripsy of calculi diseases, it lastly received high attention as a catheter-based ultrasound method to ablate thrombi and disrupt atherosclerotic plaques in interventional cardiology (Figure 1). The effect of therapeutic ultrasound to ablate selectively pathological tissue depends on its bioselectivity for elastic fibers: After ultrasound sonication, healthy tissue-rich in elastin and collagen-including arterial wall remains intact whereas thrombus and plaque with their minimal elastic support are found to be highly susceptible to ablation. Our catheter for coronary ultrasound thrombolysis (Figure 2) consists of a solid metal probe and is connected to a piezo-electric transducer at its proximal end. The distal part ends in a three-wire flexible segment with a 1.6 mm tip ball to guarantee maximal wire flexibility and optimal transmission of ultrasound energy. The initial in vitro studies resulted in a fundamental understanding of the destructive effect of ultrasound on tissue based on 4 factors: mechanical vibration, thermal effects, microcurrents, and cavitation. The first studies on human peripheral vessels were published in 1991 being performed during femoral bypass surgery on occluded and partially obstructed arteries. The procedure was performed without perforation, no adverse side effects emerged, restenosis rate was 20%. The clinical application of coronary ultrasound angioplasty was initiated in 1991; Siegel published his data on 44 patients. In his study, 30 patients with chronic atherosclerotic occlusive lesions and 14 with unstable or stable angina or AMI were treated by ultrasound angioplasty. Residual stenosis after ultrasound treatment was 71%, after balloon dilation reduced to 34%. In the 6-month follow-up angiograms showed no major adverse effect or restenosis. Our experience with coronary ultrasound thrombolysis (CUT) is based on the analysis of 33 patients' data in the feasibility (Table 1) plus multicenter phase of the ACUTE trial (Analysis of Coronary Ultrasound Thrombolysis Endpoints) (Figure 3). Our patients were exclusively treated for AMI by ultrasound angioplasty and afterwards by PTCA if required (Figure 4). The average final percent stenosis was 20% (Figure 5). The main efficacy parameters, device success and angiographic success rates were 100%, clinical success rate was 91.7% (Figure 6 and Table 2). The adverse clinical events of CUT are limited--at least in our studies--to reocclusion of infarct-related artery and ischemia and could be reversed by additional PTCA. No adverse clinical side effects were observed during sonication of the coronary tree. Final angiography revealed residual stenosis of 20% without morphological signs. These excellent results suggest that bioselectivity of ultrasound together with the developed skills of the catheter system induces rapid and selective thrombolysis with no need to cross the target lesion before sonication. But what is the better solution for thrombosis and which for plaque disruption? The development of transluminal balloon catheter really modified therapeutic approach to obstructive coronary and peripheral arterial disease but it is still accompanied by a high rate of abrupt closure, AMI and death. Although the use of intravenous thrombolytic agents is well established in the treatment of AMI and these agents are widely used, a large patient collective remains (up to 33% and more) in whom their use is inadvisable due to recent stroke, surgery, trauma or other contraindications. (ABSTRACT TRUNCATED)     

Short-term results and intermediate-term follow-up of laser wire recanalization of chronic coronary artery occlusions: a single-center experience

OBJECTIVES: This study sought to elucidate the short-term efficacy and intermediate-term outcome of excimer laser recanalization of chronic coronary artery occlusions in patients in whom attempts at mechanical revascularization had failed. BACKGROUND: Recanalization of chronic coronary occlusions with the use of a mechanical guide wire fails in 30% to 50% of cases, mostly because of inability to pass the wire through the lesion. The value of using excimer laser energy in this setting has not yet been determined. METHODS: The study group comprised 66 consecutive patients with 68 chronic coronary occlusions. Patients were eligible for inclusion in the study if a previous attempt at mechanical revascularization had failed and if their angiographic status was such that 1) the vessel segment distal to the occlusion could be visualized by way of collateral vessels, 2) the entry point of the occlusion was clearly outlined, and 3) not more than one anatomic bend was expected within the occlusion. Excimer laser energy was applied to the lesion through a 0.018-in. (0.046 cm) fiber-optic guide wire. Adjunctive balloon angioplasty and stenting were performed in all successfully treated patients but one. RESULTS: Thirty-four occlusions (50%) in 32 patients (48%) could be crossed with the laser wire. Location and age of the occlusion had no adverse influence on the outcome of laser wire recanalization, nor did the presence of bridging collateral vessels, a major side branch at the site of the lesion or a blunt stump of the occlusion. An inverse relation was found between the success rate and the length of the occlusion, such that a 19% reduction of the success rate accompanied each 10-mm increment of the mean occlusion length. Thus, the success rate was 68% for lesions < or = 10 mm but only 25% for lesions > 30 to < or = 40 mm. The presence of a bend in the lesion exceeding 60 degrees was strongly related to procedural failure. During a median angiographic follow-up period of 18 weeks, restenosis > 50% (n = 6) or reocclusion (n = 4) was found in 10 of the 32 successfully treated patients, for an intermediate-term success rate of 33% (22 of 66). Clinical follow-up revealed improved anginal status in 21 patients (66%) after a median of 24 weeks. Major complications (death, myocardial infarction, emergency operation) were not encountered. CONCLUSIONS: Successful recanalization of a chronic coronary occlusion by using currently available laser wires can be expected in 50% of selected patients in whom attempts at mechanical revascularization fail. Restenosis or reocclusion accounts for an overall 6-month success rate of 35%.     

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.     

Serial investigation of balloon angioplasty induced changes in the superficial femoral artery using colour duplex ultrasonography

Percutaneous transluminal balloon angioplasty (PTA) of superficial femoral artery lesions is associated with similar initial success rates in coronary and iliac artery angioplasty but its application is limited by a much higher incidence of restenosis. To improve understanding of the trauma caused to the vessel by balloon angioplasty and the mechanisms contributing to the subsequent processes of healing and restenosis requires serial investigations of the treated arteries in vivo. This paper describes a prospective study using colour duplex ultrasonic imaging to assess arterial changes in 51 patients with atherosclerotic disease undergoing PTA of superficial femoral artery stenoses and occlusions. Each patient was scanned prior to angioplasty and at intervals up to 6 months post-angioplasty. On each scan, measurements were made of the overall vessel and lumen diameters at each site of angioplasty. These measurements indicate that angioplasty improves vessel patency mainly by stretching of the vessel wall, with compression and/or redistribution of the atherosclerotic plaque contributing less than 25% to the improvement of lumen diameter. Serial measurements after angioplasty show complex patterns of change at the angioplasty sites indicating that several mechanisms may be contributing to the processes of vessel healing and subsequent restenosis. Possible mechanisms which could explain the measured changes in overall vessel and lumen diameters are discussed.     

Is percutaneous transluminal coronary angioplasty in chronic total coronary occlusion justified? Long term results in a series of 201 patients

Percutaneous transluminal coronary angioplasty of chronic total coronary occlusions has a low primary success rate and is associated with a high percentage of restenosis. The aim of this retrospective study was to assess the long-term benefits of these procedures. In a series of 201 patients with 203 chronic total occlusions, the technical success rate was 51%, the clinical success rate was 46% with 3% of major complications. The only factor associated with a favourable outcome was the presumed duration of the occlusion. The clinical follow-up period was established at 6 years. The result of the initial procedure was used to establish two groups of patients: group I, clinical success, and group II, clinical failure. Patients in group I had a probability of survival greater than that of those in group II (97 vs 92%; p < 0.05); survival without coronary bypass surgery was also significantly better (89 vs 74%; p < 0.003). On the other hand, the probability without angioplasty was less in group I (70 vs 77%; p < 0.01), the result of a high restenosis rate (48%). A Cox analysis identified clinical success of angioplasty as a good prognostic factor for survival. Moreover, the clinical status at long-term was significantly better in patients in group I. These results indicate that in patients with chronic total coronary occlusions, the success of angioplasty has a favourable effect on long-term outcome both in terms of survival and in quality of life. They must be interpreted in the light of the limitations inherent in a retrospective study and should be confirmed by prospective trials.     

Evaluating the potential cost-effectiveness of stenting as a treatment for symptomatic single-vessel coronary disease. Use of a decision-analytic model

BACKGROUND: Coronary stenting appears to provide more predictable immediate results and lower rates of restenosis than conventional balloon angioplasty for selected lesion types, but its hospital costs are significantly higher. This study was designed to evaluate the potential cost-effectiveness of Palmaz-Schatz coronary stenting relative to conventional balloon angioplasty for the treatment of patients with symptomatic, single-vessel coronary disease. METHODS AND RESULTS: We developed a decision-analytic model to predict quality-adjusted life expectancy and lifetime treatment costs for patients with symptomatic, single-vessel coronary disease treated by either Palmaz-Schatz stenting (PSS) or conventional angioplasty (PTCA). Estimates of the probabilities of overall procedural success (PTCA, 97%; PSS, 98%), abrupt closure requiring emergency bypass surgery (PTCA, 1.0%; PSS, 0.6%), and angiographic restenosis (PTCA, 37%; PSS, 20%) were derived from review of the literature published as of September 1993. Procedural costs were based on the true economic (ie, variable) costs of each procedure at Boston's Beth Israel Hospital. On the basis of these data, coronary stenting was estimated to result in a higher quality-adjusted life expectancy than conventional angioplasty but to incur additional costs as well. Compared with conventional angioplasty, stenting had an estimated incremental cost-effectiveness ratio of $23,600 per quality-adjusted life year gained. Although the cost-effectiveness ratio for stenting changed with variations in assumptions about the relative costs and restenosis rates, it remained less than $40,000 per quality-adjusted year of life gained--and thus was similar to many other accepted medical treatments--unless the stent angiographic restenosis rate was > 23%, the angioplasty restenosis rate was < 34%, or the cost of stenting (including vascular complications) exceeded that of conventional angioplasty by more than $3000. The alternative strategy of secondary stenting (initial angioplasty followed by stenting only for symptomatic restenosis) was estimated to be both less effective and less cost-effective than primary stenting over a wide range of plausible assumptions and thus does not appear to be cost-effective when primary stenting is also an option. CONCLUSIONS: Decision-analytic modeling can be used to evaluate the potential cost-effectiveness of new coronary interventions. Our analysis suggests that despite its higher cost, elective coronary stenting may be a reasonably cost-effective treatment for selected patients with single-vessel coronary disease. Primary stenting is unlikely to be cost-effective for lesions with a low probability of restenosis (eg, < 30%) or for patients for whom the cost of stenting is expected to be much higher than usual (eg, because of a high risk of vascular complications). Given the sensitivity of the cost-effectiveness ratios to even modest variations in the relative restenosis rates and cost estimates, future studies will be necessary to determine more precisely the cost-effectiveness of coronary stenting for specific patient and lesion subsets.     

The relation between multiple sleep latency test findings and the frequency of apneic events in REM and non-REM sleep

OBJECTIVES: The purpose of this prospective study was to evaluate the immediate results and the 6-month angiographic recurrent restenosis rate after balloon angioplasty for in-stent restenosis. BACKGROUND: Despite excellent immediate and mid-term results, 20% to 30% of patients with coronary stent implantation will present an angiographic restenosis and may require additional treatment. The optimal treatment for in-stent restenosis is still unclear. METHODS: Quantitative coronary angiography (QCA) analyses were performed before and after stent implantation, before and after balloon angioplasty for in-stent restenosis and on a 6-month systematic coronary angiogram to assess the recurrent angiographic restenosis rate. RESULTS: Balloon angioplasty was performed in 52 patients presenting in-stent restenosis. In-stent restenosis was either diffuse (> or =10 mm) inside the stent (71%) or focal (29%). Mean stent length was 16+/-7 mm. Balloon diameter of 2.98+/-0.37 mm and maximal inflation pressure of 10+/-3 atm were used for balloon angioplasty. Angiographic success rate was 100% without any complication. Acute gain was lower after balloon angioplasty for in-stent restenosis than after stent implantation: 1.19+/-0.60 mm vs. 1.75+/-0.68 mm (p=0.0002). At 6-month follow-up, 60% of patients were asymptomatic and no patient died. Eighteen patients (35%) had repeat target vessel revascularization. Angiographic restenosis rate was 54%. Recurrent restenosis rate was higher when in-stent restenosis was diffuse: 63% vs. 31% when focal, p=0.046. CONCLUSIONS: Although balloon angioplasty for in-stent restenosis can be safely and successfully performed, it leads to less immediate stenosis improvement than at time of stent implantation and carries a high recurrent angiographic restenosis rate at 6 months, in particular in diffuse in-stent restenosis lesions.     

The use of relational databases in the transition from quality assurance to continuous quality improvement: a clinical practice model

BACKGROUND AND OBJECTIVE: The solid-state, mid-infrared holmium:YAG laser (2.1 microm wavelength) is a relatively new percutaneous device that has recently been evaluated in a multicenter study. Because of its unique wavelength and photoacoustic effects on atherosclerotic plaques, this laser may be useful in treatment of symptomatic patients with coronary artery disease. This study sought to evaluate the safety and efficacy of mid-infrared laser angioplasty in the treatment of coronary artery lesions. PATIENTS AND METHODS: Laser angioplasty was performed on 2,038 atherosclerotic lesions in 1,862 consecutive patients with a mean age of 61 +/- 11 years. Clinical indications included unstable angina (69%), stable angina (20%), acute infarction (6%), and positive exercise test (5%). Complex lesion morphology included eccentricity (62%), thrombus (30%), total occlusion (27%), long lesions (14%), and saphenous vein grafts (11%). RESULTS: This laser catheter alone successfully reduced stenosis (>20%) in 87% of lesions. With adjunct balloon angioplasty, 93% procedural success was achieved. The presence of thrombus within the target lesion was a predictor of procedural success (OR = 2.0 [95% confidence interval 2.0, 4.0], P = .04). Bifurcation lesions (OR = 0.5 [95% confidence interval 0.2, 1.0], P = .05) and severe tortuosity of the treated vessel (OR = 0.4 [95% confidence interval 0.2, 0.9], P = .02) were identified as significant predictors of decreased laser success. Calcium within the lesion was associated with reduced procedural success (OR = 0.57 [95% confidence interval 0.34, 0.97], P = .03), and calcified lesions required significantly more energy pulses than noncalcified lesions (119 +/- 91 pulses vs. 101 +/- 86 pulses, respectively, P = .0002). Complications included in-hospital bypass surgery 2.5%, Q-wave myocardial infarction 1.2%, and death 0.8%. Perforation occurred in 2.2% of patients; major dissection in 5.8% of patients, and spasm in 12% of patients. No predictor of major complications was identified. Six-month angiographic restenosis was documented in 54% of patients, and clinical restenosis occurred in 34% of patients. CONCLUSION: Mid-infrared laser has a safety profile similar to that of other debulking devices. This laser may be useful in select patients presenting with acute ischemic syndromes associated with intracoronary thrombus; however, like other coronary lasers, it is limited by the need for adjunctive balloon angioplasty and/or stenting to achieve adequate final luminal diameter. No beneficial effects on reducing 6-month restenosis rates were observed.     

Immediate and long-term effect of balloon angioplasty or stent implantation on the absolute and relative coronary blood flow velocity reserve

BACKGROUND: There is controversy regarding the immediate and long-term effects of PTCA on the coronary flow reserve. METHODS AND RESULTS: A total of 54 patients with 1-vessel disease and normal left ventricular function were studied after balloon angioplasty (n=34) or stent implantation (n=20). Distal coronary blood flow velocity reserve (CFR) was defined as the ratio of adenosine-induced hyperemic versus baseline blood flow velocity with a 0.014-in Doppler guidewire. The relative CFR was defined as the ratio of the distal CFR and the reference CFR measured in the normal adjacent coronary artery. Hemodynamic and angiographic measurements were performed before and directly after balloon angioplasty or stent implantation and at 6-month follow-up. CFR after PTCA 相似文献