Influence of a history of smoking on short term (six month) clinical and angiographic outcome after successful coronary angioplasty.

OBJECTIVES: To assess the influence of smoking on restenosis after coronary angioplasty. DESIGN AND PATIENTS: The incidence of smoking on restenosis was investigated in 2948 patients. They were prospectively enrolled in four major restenosis trials in which quantitative angiography was used before and immediately after successful angioplasty and again at six months. RESULTS: Within the study population there were 530 current smokers, 1690 ex-smokers, and 728 non-smokers. Smokers were more likely to be men (85.9% v 87. 5% v 65.3%, current v ex- v non-, p < 0.001), to be younger (54.0 (9. 0) v 57.0 (9.1) v 59.9 (9.4) years, p < 0.001), to have peripheral vascular disease (7.2% v 5.5% v 2.3%, p < 0.001), and have sustained a previous myocardial infarction (42.9% v 43.9% v 37.9%, p = 0.022), but were less likely to be diabetic (9.1% v 9.5% v 12.6%, p = 0.043) or hypertensive (24.9% v 29.3% v 37.2, p < 0.001). There was no significant difference in the categorical restenosis rate (> 50% diameter stenosis) at six months (35.28% v 35.33% v 37.09%, current v ex- v non-), or the absolute loss (0.29 (0.54) v 0.33 (0.52) v 0. 35 (0.55) mm, respectively; p = 0.172). CONCLUSIONS: Although smokers have a lower incidence of known predisposing risk factors for atherosclerosis, they require coronary intervention almost six years earlier than non-smokers and three years earlier than ex-smokers. Once they undergo successful coronary angioplasty, there appears to be no evidence that smoking influences their short term (six month) outcome, but because of the known long term effects of smoking, patients should still be encouraged to discontinue the habit.

Comparison of coronary luminal quantification obtained from intracoronary ultrasound and both geometric and videodensitometric quantitative angiography before and after balloon angioplasty and directional atherectomy.

BACKGROUND: Debate exists regarding the relationship between angiographic and intracoronary ultrasound (ICUS) measurements of minimal luminal cross-sectional area after coronary intervention. We investigated this and the factors that may influence it by using ICUS and quantitative angiography. METHODS AND RESULTS: Patients who underwent successful balloon angioplasty (n=100) or directional atherectomy (n=50) were examined by using ICUS and quantitative angiography (edge-detection [ED] and videodensitometry [VID]) before and after intervention. Luminal damage postintervention was qualitatively graded into three categories based on angiographic results (smooth lumen, haziness, or dissection). Correlation of minimal luminal cross-sectional area measurements by ICUS and ED was .59 before and .47 after balloon angioplasty. Correlation between ICUS and VID was .50 before and .63 after balloon angioplasty. Postintervention, the difference between ICUS and VID was less than the difference between ICUS and ED (P<.01). Additionally, the correlation was .74 between ICUS and ED measurements and .78 between ICUS and VID measurements in the smooth lumen group, .46 and .63, respectively, in the presence of haziness, and .26 and .46, respectively, in lesions with dissection. Similar results were obtained after directional atherectomy: the agreement between ICUS and quantitative angiography deteriorated according to the degree of vessel damage, but less so with VID than ED. CONCLUSIONS: Complex morphological changes induced by intervention may contribute to discordance between the two quantitative imaging techniques. In the absence of ICUS, VID may be a complementary technique to ED in lesions with complex morphology after balloon angioplasty and directional atherectomy.

Endovascular stents: a 'break through technology', future challenges.

Coronary stents were developed to overcome the two main limitations of balloon angioplasty, acute occlusion and long term restenosis. Coronary stents can tack back intimal flaps and seal the dissected vessel wall and thereby treat acute or threatened vessel closure after unsuccessful balloon angioplasty. Following successful balloon angioplasty stents can prevent late vessel remodeling (chronic vessel recoil) by mechanically enforcing the vessel wall and resetting the vessel size resulting in a low incidence of restenosis. All currently available stents are composed of metal and the long-term effects of their implantation in the coronary arteries are still not clear. Because of the metallic surface they are also thrombogenic, therefore rigorous antiplatelet or anticoagulant therapy is theoretically required. Furthermore, they have an imperfect compromise between scaffolding properties and flexibility, resulting in an unfavourable interaction between stents and unstable or thrombus laded plaque. Finally, they still induce substantial intimal hyperplasia which may result in restenosis. Future stent can be made less thrombogenic by modifying the metallic surface, or coating it with an antithrombotic agent or a membrane eluting an antithrombotic drug. The unfavourable interaction with the unstable plaque and the thrombus burden can be overcome by covering the stent with a biological conduit such as a vein, or a biodegradable material which can be endogenous such as fibrin or exogenous such as a polymer. Finally the problem of persisting induction of intimal hyperplasia may be overcome with the use of either a radioactive stent or a stent eluting an antiproliferative drug.

New stent technologies.

Coronary stents were developed to overcome the two main limitations of balloon angioplasty, acute occlusion and long-term restenosis. Coronary stents can tack back intimal flaps and seal the dissected vessel wall, thereby treating acute or threatened vessel closure after unsuccessful balloon angioplasty. After successful balloon angioplasty, stents can prevent late vessel remodeling (chronic vessel recoil) by mechanically enforcing the vessel wall and resetting the vessel size, resulting in a low incidence of restenosis. All currently available stents are composed of metal, and the long-term effects of their implantation in the coronary arteries are still not clear. Because of the metallic surface, they are also thrombogenic; therefore, rigorous antiplatelet or anticoagulant therapy is theoretically required. Furthermore, they have an imperfect compromise between scaffolding properties and flexibility, resulting in an unfavorable interaction between stents and unstable or thrombus-laden plaque. Finally, they still induce substantial intimal hyperplasia that may result in restenosis. Future stents can be made less thrombogenic by modifying the metallic surface or coating it with an antithrombotic agent or a membrane eluting an antithrombotic drug. The unfavorable interaction with the unstable plaque and the thrombus burden can be overcome by covering the stent with a biological conduit, such as a vein, or a biodegradable material that can be endogenous, such as fibrin, or exogenous, such as a polymer. Finally, the problem of persisting induction of intimal hyperplasia may be overcome with the use of either a radioactive stent or a stent eluting an antiproliferative drug.

Short- and long-term clinical and quantitative angiographic results with the new, less shortening Wallstent for vessel reconstruction in chronic total occlusion: a quantitative angiographic study.

OBJECTIVES: This study was designed to examine whether oversized implantation of the new, less shortening Wallstent provides a more favorable long-term clinical and angiographic outcome in chronic total occlusions than does conventional coronary balloon angioplasty. BACKGROUND: Restenosis and reocclusion remain major limitations of balloon angioplasty for chronic total occlusions. Enforced mechanical remodeling by implantation of the oversized Wallstent may prevent elastic recoil and improve accommodation of intimal hyperplasia. METHODS: Lumen dimension was measured by a computer-based quantitative coronary angiography system (CAAS II). These measurements (before and after intervention and at 6-month follow-up) were compared between the groups with Wallstent implantation (20 lesions, 20 patients) and conventional balloon angioplasty (266 lesions, 249 patients) for treatment of chronic total occlusion. Acute gain (minimal lumen diameter after intervention minus that before intervention), late loss (minimal lumen diameter after intervention minus that at follow-up) and net gain (acute gain minus late loss) were examined. RESULTS: Wallstent deployment was successful in all patients. High pressure intra-Wallstent balloon inflation (mean +/- SD 14 +/- 3 atm) was performed in all lesions. Although vessel size did not differ between the Wallstent and balloon angioplasty groups, acute gain was significantly greater in the Wallstent group (2.96 +/- 0.55 vs. 1.61 +/- 0.34 mm, p < 0.0001). Although late loss was also significantly larger in the Wallstent group (0.81 +/- 0.95 vs. 0.43 +/- 0.68 mm, p < 0.05), net gain was still significantly greater in this group (2.27 +/- 1.00 vs. 1.18 +/- 0.69 mm, p < 0.0001). Angiographic restenosis (> or = 50% diameter stenosis) occurred at 6 months in 29% of lesions in the Wallstent group and in 45% of those in the balloon angioplasty group (p = 0.5150). CONCLUSIONS: Implantation of the oversized Wallstent, with full coverage of the lesion length, ensures resetting of the vessel size to its original caliber before disease and allows greater accommodation of intimal hyperplasia and chronic vessel recoil. Wallstent implantation provides a more favorable short- and long-term clinical and angiographic outcome than does conventional balloon angioplasty for chronic total occlusions.

Role of angiographically identifiable thrombus on long-term luminal renarrowing after coronary angioplasty: a quantitative angiographic analysis.

BACKGROUND: Experimental studies suggest that mural thrombus may be involved in postangioplasty restenosis. The aim of our study was to examine the role of angiographically identifiable thrombus in the clinical situation. METHODS AND RESULTS: The study population comprised 2950 patients (3583 lesions). The presence of angiographically identifiable thrombus either before or after the procedure was defined as the presence of a generalized haziness or filling defect within the arterial lumen. Restenosis was assessed by both a categorical (> 50% diameter stenosis at follow-up) and a continuous approach (absolute and relative losses). The study population included 160 lesions with and 3423 lesions without angiographically identifiable thrombus. The categorical restenosis rate was significantly higher in lesions containing angiographically identifiable thrombus: 43.1% versus 34.4%, P < .01; relative risk, 1,449; CI, 1.051 to 1.997. The absolute and relative losses were also higher in lesions containing angiographically identifiable thrombus (absolute loss, 0.43 +/- 0.66 versus 0.32 +/- 0.52; relative loss, 0.16 +/- 0.26 versus 0.13 +/- 0.21; both P < .05). The higher restenosis in these lesions was due primarily to an increased incidence of occlusion at follow-up angiography in this group: 13.8% versus 5.7%, P < .001. When lesions that went on to occlude by the time of follow-up angiography were excluded from the analysis, the restenosis rate between the two groups was similar by both the categorical (34.1% versus 30.4%, P=NS; relative risk, 1.183; CI, 0.824 to 1.696) and continuous (absolute loss, 0.23 +/- 0.46 versus 0.24 +/- 0.42, P=NS; relative loss, 0.09 +/- 0.17 versus 0.09 +/- 0.16, P=NS) approaches. CONCLUSIONS: Our results indicate that the presence of angiographically identifiable thrombus at the time of the angioplasty is associated with higher restenosis. The mechanism by which this occurs is through vessel occlusion at follow-up angiography. Measures aimed at improving outcome in this group of patients should be focused in this direction.

Long-term luminal renarrowing after successful elective coronary angioplasty of total occlusions. A quantitative angiographic analysis.

BACKGROUND: The long-term angiographic outcome after successful dilatation of coronary occlusions remains unclear. The objective of this study was to examine long-term restenosis after successful balloon dilatation of coronary occlusions at a predetermined time interval with quantitative angiography and compare this with a control population of stenoses. METHODS AND RESULTS: The study population comprised 2950 patients (3583 lesions) prospectively enrolled in and successfully completing four major restenosis trials (86% quantitative angiographic follow-up). Cineangiographic films were processed and analyzed at a central core laboratory with the use of an automated interpolated edge detection technique. The study population comprised 266 occlusions (7%) defined as total when there was absent anterograde filling beyond the lesion (109 lesions) and functional (157 lesions) when faint, late anterograde opacification of the distal segment was seen in the absence of a discernible luminal continuity; 3317 lesions were defined as stenoses (93%). Restenosis was significantly higher after successful dilatation of occlusions than of stenoses. With the categorical (> 50% diameter stenosis at follow-up) approach, the restenosis rate was 44.7% in occlusions compared with 34.0% in stenoses (P < .001; relative risk, 1.575; CI, 1.224 to 2.027). Similarly, the absolute loss (defined as the change in minimal lumen diameter between post coronary angioplasty and follow-up; in millimeters, mean +/- SD) (0.43 +/- 0.68) in occlusions was significantly higher than in stenoses (0.31 +/- 0.51, P < .001), as was the relative loss, defined as the change in minimal lumen diameter between postangioplasty and follow-up, adjusted for the vessel size (0.17 +/- 0.28 versus 0.12 +/- 0.20, P < .001). The higher restenosis rate in the occlusions group was due predominantly to an increased number of occlusions at follow-up angiography in this group (19.2% compared with 5.0% for stenoses, P < .001). Within the occlusions group, there were no significant differences in long-term outcome between total and functional occlusions (restenosis rate, 45.0% versus 44.6%; reocclusion rate, 23.9% versus 15.9%; absolute loss, 0.53 +/- 0.69 versus 0.36 +/- 0.67; relative loss, 0.21 +/- 0.28 versus 0.15 +/- 0.28; P = NS). CONCLUSIONS: These results indicate that successfully dilated coronary occlusions, both total and functional, have a higher rate of angiographic restenosis at 6 months than stenoses. This is due chiefly to a higher rate of occlusion at follow-up angiography in this group of lesions. Measures aimed at reducing restenosis after successful dilatation of coronary occlusion should be focused in this direction.

Influence of serum cholesterol and cholesterol subfractions on restenosis after successful coronary angioplasty. A quantitative angiographic analysis of 3336 lesions.

BACKGROUND: Previous reports have suggested that hyperlipidemia may be associated with increased restenosis after successful coronary angioplasty. These studies have been compromised, however, by their retrospective nature, the small numbers involved, differences in the definition of restenosis, and inadequate quantitative angiographic follow-up at a prespecified time interval. The objective of the study was to examine the relation between serum cholesterol and long-term restenosis after coronary angioplasty, using quantitative angiography, at a predetermined time interval. METHODS AND RESULTS: The study population comprised 2753 patients (3336 lesions) prospectively enrolled and successfully completing four major restenosis trials. Cineangiographic films were processed and analyzed at a central angiographic core laboratory with the use of an automated interpolated edge-detection technique. Serum total cholesterol was measured at trial entry and at 6 months. Hypercholesterolemia was defined as total cholesterol > 7.8 mmol.L-1 at trial entry. Two approaches were used to assess restenosis: first, a categorical approach using the cutoff point of > 50% diameter stenosis at follow-up and second, a continuous approach examining changes in minimal luminal dimensions, the absolute loss (change in minimum luminal diameter after PTCA to follow-up, in mm) and relative loss (absolute loss corrected for vessel size), which may give a better understanding of the underlying pathological process involved. One hundred sixty patients with 191 lesions (5.73%) had hypercholesterolemia (total cholesterol, > 7.8 mmol.L-1; mean +/- SD, 8.46 +/- 0.75 mmol.L-1) and 2593 patients with 3145 lesions (94.27%) normal cholesterol (5.67 +/- 1.06 mmol.L-1). The restenosis rate was similar in patients with and without hypercholesterolemia (31.9% versus 33.7%, respectively; relative risk, 0.975; 95% CI, 0.882 to 1.077; P = .68). Similarly, there was no difference in either the absolute or relative loss between patients with and without hypercholesterolemia (0.31 +/- 0.53 versus 0.32 +/- 0.53 mm and 0.12 +/- 0.20 versus 0.13 +/- 0.21, respectively, P = NS for both). Conversely, the total serum cholesterol in patients with restenosis (using the categorical definition) was similar to those without restenosis (5.84 +/- 1.24 versus 5.81 +/- 1.22 mmol/L, respectively, P = NS). Dividing the population into deciles according to total cholesterol and examining the categorical restenosis rate (by chi 2) as well as the absolute and relative loss by ANOVA again revealed no significant differences between deciles. Subgroup analysis of 579 patients (667 lesions) with HDL and LDL cholesterol levels available again revealed no differences in the categorical restenosis rate (by chi 2) or the absolute or relative loss between deciles according to LDL, HDL, or LDL:HDL ratio, suggesting no influence of these cholesterol subfractions on restenosis. CONCLUSIONS: Our results indicate that there is no association between cholesterol and restenosis by either a categorical or continuous approach, suggesting that measures aimed at reducing total cholesterol are unlikely to significantly influence postangioplasty restenosis.

New technologies in interventional cardiology.

The limitations of balloon angioplasty have led to the introduction of new devices designed to improve the short- and long-term efficacy of percutaneous revascularization techniques. Preliminary single-operator experience and registry data have suggested that these devices may be useful in particular anatomical situations. Last year saw the beginning of the next phase of device assessment, the randomized study, directly comparing the new devices with coronary angioplasty either in the total angioplasty patient population or in selected subgroups. Two major randomized studies, the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT) and the Canadian Coronary Atherectomy Trial (CCAT), directly compared directional coronary atherectomy with balloon angioplasty and suggested that coronary atherectomy offers no particular advantage over balloon angioplasty. This year will see the publication of the Belgium Netherlands Stent (BENESTENT) and Stent Restenosis Study (STRESS) randomized trials, which compared coronary stents with balloon angioplasty; further studies comparing balloon angioplasty with other devices are currently under way. We are now entering a new era where randomized studies will directly assess the safety and efficacy of the new devices compared with balloon angioplasty and demonstrate, in a scientific manner, the validity (or otherwise) of their superiority over balloon angioplasty.

Luminal narrowing after percutaneous transluminal coronary angioplasty. A multivariate analysis of clinical, procedural and lesion related factors affecting long-term angiographic outcome in the PARK study. Post-Angioplasty Restenosis Ketanserin.

BACKGROUND: Long term luminal renarrowing after successful coronary balloon angioplasty is a major limitation of the technique. Knowledge of factors which influence long term luminal re-narrowing could be very valuable in selecting appropriate patients or lesions for the procedure and may therefore improve the medium term prognosis after angioplasty. Furthermore, modification or control of the identified risk factors could reduce overall restenosis. Additionally, identification of such factors would assist in the selection of high risk patients, who could then constitute the target population for pharmacological intervention studies. Thus the aims of the present study were to find independent patient, lesion and procedural related risk factors for the restenosis process. METHODS AND RESULTS: Quantitative angiography was performed on 742 successfully dilated lesions at angioplasty and 6 months follow-up. Long-term luminal re-narrowing was defined as the absolute change in minimal luminal diameter (MLD) from post PTCA to follow up. Univariate and multiple linear regression analysis of all available clinical, lesion and procedural variables was performed to identify variables with a significant contribution to the prediction of change in MLD. Gain in MLD at angioplasty, pre PTCA MLD, total inflation time and male sex were positively related to change in MLD while a positive smoking history, vessel and maximum balloon size were negatively related. The overall prediction of the model was poor (R2-0.14) suggesting that many factors influencing the process are still outside our understanding. CONCLUSIONS: These results indicate that re-narrowing after successful PTCA is a process which can be influenced by a number of clinical, angiographic and procedural characteristics but cannot yet be accurately predicted by these.

Myocardial revascularisation in the elderly: complementary roles for coronary angioplasty and bypass grafting.

Coronary artery disease is a common finding, responsible for substantial morbidity and mortality in the elderly. Despite this, there is a general reluctance to refer elderly patients for further investigation as the perceived risks are thought to outweight any potential benefit. This is not however borne out by the available evidence, which suggests that revascularisation procedures carry little additional risk in appropriately selected elderly patients. Chronological age per se should, therefore, no longer be a bar to myocardial revascularisation.

Variable and circadian response to a fixed high-dose (12 500 IU twice daily) subcutaneous heparin regimen after thrombolytic therapy for acute myocardial infarction.

AIM: To determine the effect of a fixed high-dose (12 500 IU twice daily) subcutaneous heparin regimen on coagulation parameters after thrombolysis with streptokinase. BACKGROUND AND METHODS: A number of large thrombolytic trials have allocated patients to fixed high-dose (12 500 IU twice daily) subcutaneous heparin with no monitoring of coagulation parameters. We hypothesized that heparin's apparent lack of benefit and increased haemorrhagic complications in these trials may be the result of inappropriate anticoagulation. We therefore studied 11 patients who received intravenous streptokinase and oral aspirin for acute myocardial infarction and were subsequently started on the above heparin regimen. Blood samples were taken for activated partial thromboplastin time (APTT) and thrombin time before streptokinase and then immediately before and 6 h after each heparin injection on days 1,4, and 6, and 3 and 6 h after streptokinase on day 5. Plasma heparin levels were also measured on all post-streptokinase samples. Plasma fibrinogen was measured before the administration of streptokinase and once daily on the other sampling days. RESULTS: Both the median APTT and thrombin time were prolonged above the normal range throughout day 1, when fibrinogen levels were depressed, with a non-significant variation between the sampling points. By day 4, however, when fibrinogen levels had returned to pre-streptokinase levels, the median (range) APTTs at 8 a.m. and 8 p.m. (pre-heparin) were similar, and below the therapeutic range, at 52 (38-76) and 48 (39-79) s (NS). Six hours after each heparin injection the APTTs were elevated, but the median (range) 2 p.m. peak of 63 (46-138) s was lower than that at 2 a.m., 125 (58-178) s (P = 0.003). A similar peak and trough, and apparent circadian, APTT response pattern was seen on days 5 and 6. The thrombin time showed the same variation, which was also mirrored in the plasma heparin levels, although the circadian effect was not as marked. CONCLUSION: There is a marked individual variation in response to fixed-dose (12 500 IU twice daily) subcutaneous heparin, with many patients inadequately anticoagulated and an obvious circadian pattern of response. These findings have important implications when considering the benefits and haemorrhagic complications of subcutaneous heparin therapy in general and following thrombolysis in particular.

Clinical and histological determinants of smooth-muscle cell outgrowth in cultured atherectomy specimens: importance of thrombus organization.

BACKGROUND: Coronary atherectomy provides a unique opportunity to obtain plaque tissue from a wide variety of clinical syndromes. We investigated the relation between the clinical status and histopathological substrate of tissue retrieved during directional coronary atherectomy and the proliferative and migratory potential of smooth-muscle cells judged from successful outgrowth during cell culture. METHODS: After directional coronary atherectomy, tissue samples were examined macroscopically, divided into two equal pieces, and separately subjected to cell culture and histopathological study. Cell culture was performed using an explant technique. In-vitro smooth-muscle cell outgrowth was related to clinical and histological variables. RESULTS: Atherosclerotic tissue was obtained from 98 consecutive atherectomy procedures. Histological examination revealed a broad spectrum of appearances, ranging from complex atheroma containing dense fibrous tissue, calcium deposits, macrophages, and necrotic debris to neointimal proliferation and organized thrombi. Smooth-muscle cell outgrowth was observed in 43 of the 98 samples (44%). Although not affected by any of the clinical variables, cell outgrowth was influenced by histological variables, in particular the presence of organizing thrombi. Outgrowth was successful in eight out of 10 samples with thrombus (80%) and in only 35 out of 88 (40%) without (P = 0.03). CONCLUSION: The presence of organizing thrombi in the retrieved tissue facilitates smooth-muscle cell outgrowth and suggests an enhanced proliferative and migratory potential. These findings may be relevant to the understanding of neointimal proliferation in coronary syndromes where mural thrombosis is likely to occur.

Effects of external stenting on wall thickening in arteriovenous bypass grafts.

Late occlusion of the saphenous vein graft appears to result in part from wall thickening as an adaptation to increased mean wall stress. Using an established pig model of arteriovenous bypass grafting, the effect of reducing wall stress with an external porous polytetrafluoroethylene stent was investigated. Segments of autologous saphenous vein were implanted by end-to-end anastomoses into both carotid arteries, with one graft supported by a stent 4 mm in diameter. Increases in graft wall dimensions were quantified 4 weeks later by computer-aided planimetry of transverse histological sections. The contribution of hyperplasia (i.e., cell proliferation) to the changes observed was further clarified by measurements of DNA concentration. All grafts showed an increase in external size, but this was restricted by stenting. All grafts also showed an increase in cross-sectional area of the tunica media and tunica intima that was only partly accounted for by an increase in DNA concentration, which indicated that both hyperplasia and hypertrophy had occurred. Stented grafts showed less enlargement of the media but greater enlargement of the intima. Overall wall size was therefore similar in stented and unstented grafts. Stented grafts showed less increase in DNA concentration than unstented grafts. In stented grafts, the residual luminal cross-sectional area was significantly less than in unstented grafts. The data show that external stenting reduces medial enlargement and hyperplasia but increases encroachment of the intima into the lumen. Because final luminal size is thought to be of paramount importance in maintaining long-term patency, external stenting is unlikely to be of benefit.

Tracker tricks: applications of a novel infusion catheter in coronary intervention.

The "Tracker" is a highly trackable and readily exchangeable catheter which can be used to facilitate coronary angioplasty in situations where the guide wire is unable to cross the lesion and is buckling under pressure. In addition it is also useful in assessing the severity of borderline coronary artery stenoses and for local infusion therapy.

Heparin in coronary artery disease: new uses for an old drug.

The role of heparin in the treatment of coronary artery disease remains unclear. Although of benefit in unstable angina and the prevention of acute occlusion following angioplasty, its value as adjunctive therapy in myocardial infarction is limited. Further studies are needed to assess the effect of heparin on angioplasty restenosis and late venous graft occlusion.

Intravascular ultrasound imaging combined with coronary angioplasty.

A novel catheter combining ultrasound imaging and coronary balloon angioplasty was used in the treatment of 69 coronary-artery lesions in 51 patients. The ultrasound transducer enables real-time cross-sectional imaging and qualitative and quantitative assessment of the vessel wall before and after angioplasty. The combination catheter successfully dilated 67 lesions. There was a characteristic three-layered appearance, representing intima, media, and adventitia, in 60 cases. Intravascular imaging provided information on the vessel wall unobtainable by standard contrast angiography in 28 cases and influenced our management in 6 cases.