Survival following coronary angioplasty versus coronary artery bypass surgery in anatomic subsets in which coronary artery bypass surgery improves survival compared with medical therapy. Results from the Bypass Angioplasty Revascularization Investigation (BARI).

OBJECTIVES: We sought to compare survival after coronary artery bypass graft (CABG) and percutaneous transluminal coronary angioplasty (PTCA) in high-risk anatomic subsets. BACKGROUND: Compared with medical therapy, CABG decreases mortality in patients with three-vessel disease and two-vessel disease involving the proximal left anterior descending artery (LAD), particularly if left ventricular (LV) dysfunction is present. How survival after PTCA and CABG compares in these high-risk anatomic subsets is unknown. METHODS: In the Bypass Angioplasty Revascularization Investigation (BARI), 1,829 patients with multivessel disease were randomized to an initial strategy of PTCA or CABG between 1988 and 1991. Stents and IIb/IIIa inhibitors were not utilized. Since patients in BARI with diabetes mellitus had greater survival with CABG, separate analyses of patients without diabetes were performed. RESULTS: Seven-year survival among patients with three-vessel disease undergoing PTCA and CABG (n = 754) was 79% versus 84% (p = 0.06), respectively, and 85% versus 87% (p = 0.36) when only non-diabetics (n = 592) were analyzed. In patients with three-vessel disease and reduced LV function (ejection fraction <50%), seven-year survival was 70% versus 74% (p = 0.6) in all PTCA and CABG patients (n = 176), and 82% versus 73% (p = 0.29) among non-diabetic patients (n = 124). Seven-year survival was 87% versus 84% (p = 0.9) in all PTCA and CABG patients (including diabetics) with two-vessel disease involving the proximal LAD (n = 352), and 78% versus 71% (p = 0.7) in patients with two-vessel disease involving the proximal LAD with reduced LV function (n = 72). CONCLUSION: In high-risk anatomic subsets in which survival is prolonged by CABG versus medical therapy, revascularization by PTCA and CABG yielded equivalent survival over seven years.

Relationship of extent of revascularization with angina at one year in the Bypass Angioplasty Revascularization Investigation (BARI).

OBJECTIVES: To determine the relative degree of revascularization obtained with bypass surgery versus angioplasty in a randomized trial of patients with multivessel disease requiring revascularization (Bypass Angioplasty Revascularization Investigation [BARI]), one-year catheterization was performed in 15% of patients. BACKGROUND: Complete revascularization has been correlated with improved outcome after coronary artery bypass grafting (CABG) but not with percutaneous transluminal coronary angioplasty (PTCA). Relative degrees of revascularization after PTCA and surgery have not been previously compared and correlated with symptoms. METHODS: Consecutive patients at four BARI centers consented to recatheterization one year after revascularization. Myocardial jeopardy index (MJI), the percentage of myocardium jeopardized by > or =50% stenoses, was compared and correlated with angina status. RESULTS: Angiography was completed in 270 of 362 consecutive patients (75%) after initial CABG (n = 135) or PTCA (n = 135). Coronary artery bypass grafting patients had 3+/-0.9 distal anastomoses and PTCA patients had 2.4+/-1.1 lesions attempted at initial revascularization. At one year, 20.5% of CABG patients had > or =1 totally occluded graft and 86.9% of vein graft, and 91.6% of internal mammary artery distal anastomotic sites had <50% stenosis. One year jeopardy index in surgery patients was 14.1+/-11%, 46.6+/-20.3% improved from baseline. Initial PTCA was successful in 86.9% of lesions and repeat revascularization was performed in 48.4% of PTCA patients by one year. Myocardial jeopardy index one year after PTCA was 25.5+/-22.8%, an improvement of 33.8+/-26.1% (p<0.01 for greater improvement with CABG than PTCA). At one year, 29.6% of PTCA patients had angina versus 11.9% of surgery patients, p = 0.004. One-year myocardial jeopardy was predictive of angina (odds ratio 1.28 for the presence of angina per every 10% increment in myocardial jeopardy, p = 0.002). Randomization to PTCA rather than CABG also predicted angina (odds ratio 2.19, p = 0.03). CONCLUSIONS: In this one-year angiographic substudy of BARI, CABG provided more complete revascularization than PTCA, and CABG likewise improved angina to a greater extent than PTCA.

Structural constriction of the artery wall contributes to stenosis severity in unstable angina.

Eight consecutive patients with unstable angina underwent intravascular ultrasound imaging of the culprit artery with measurements recorded at the stenosis and at an adjacent reference site. In all patients, total artery cross-sectional area was smaller at the stenosis site than at the reference site, indicating that a structural change in the artery wall due to a constrictive process appears to contribute to the worsening of stenosis severity associated with unstable angina.

Angiographic correlates of lesion relevance and suitability for percutaneous transluminal coronary angioplasty and coronary artery bypass grafting in the Bypass Angioplasty Revascularization Investigation study (BARI).

The Bypass Angioplasty Revascularization Investigation (BARI) randomized 1,829 patients to percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG). Clinical site angiographers categorized lesions of > or = 50% diameter stenosis (n = 4,977) as clinically significant (86.4%) or nonsignificant (13.6%), and as favorable or nonfavorable for PTCA or CABG. More lesions were considered favorable for revascularization by CABG than by PTCA (91.5% vs 78.4%; p <0.001), particularly in the subgroup of 99% to 100% lesions (77.6% for CABG vs 21.9% for PTCA, p <0.001). Lesion features, characterized by the BARI core laboratory, were correlated with clinical site angiographers' assessment of clinical importance and suitability for PTCA or CABG. By multivariate analysis, positive predictors of clinical importance for 50% to 95% stenoses were greater stenosis severity, more jeopardized myocardium, larger reference diameter, and proximal vessel location. For 99% to 100% occlusions, predictors were shorter duration of occlusion and more jeopardized myocardium. PTCA suitability for 50% to 95% stenoses was inversely related to lesion length, ostial location, location on a bend, difficult access, and age, and was directly associated with greater Thrombolysis in Myocardial Infarction (TIMI) trial flow rate and more jeopardized myocardium. Predictors of PTCA suitability for 99% to 100% lesions were a lower American College of Cardiology/American Heart Association class and higher TIMI grade. Predictors for 50% to 95% stenoses were more jeopardized myocardium, larger reference diameter, and more proximal vessel location, and for 99% to 100% occlusions, more jeopardized myocardium and shorter duration of occlusion. Suitability for PTCA depended on lesion potency (<99%) and multiple morphologic characteristics that contrasted with the few angiographic features that adversely affect CABG suitability.

Does sequential balloon injury of an artery lead to a different outcome than a single injury? An experimental study of angioplasty.

BACKGROUND: Mechanisms of stenosis after angioplasty are often studied in experimental models created by injury of normal arteries. Sequential rather than single insult may provide the better model. We compared the response of arteries to these two types of injury. METHODS: Two groups of arteries of cholesterol-fed New Zealand white rabbits were compared: single balloon injury arteries and two sequential balloon injury arteries (14-day interval between injuries). At 1-49 days after the first injury lumen dimensions and number of cells and cell proliferation in the media and neointima were assessed. RESULTS: Single injury resulted in cell proliferation in the artery wall, formation of neointimal, and progressive loss of lumen diameter. In sequentially injured arteries, the second injury caused an immediate increase in angiographic lumen diameter from 1.6 +/- 0.1 mm to 2.0 +/- 0.1 mm but the lumen decreased to 1.3 +/- 0.3 mm by 28 days after the second injury, consistent with restenosis. At late time points after injury the lumen diameter was similar in the two groups of arteries. The sequential lesion neointimal area increased at the same rate as the primary lesion neointimal. The second of the sequential injuries stimulated cell proliferation activity in the vessel wall that was similar in magnitude to that seen after primary injury. CONCLUSIONS: These findings suggest that the primary injury process initiated mechanisms that determine the rate of neointimal area formation and lumen dimensions over the 5-6 week time interval studied here. The second of the sequential injuries initiated a cell proliferation response in the artery wall but did not alter the neointimal area or lumen caliber consequences of primary injury.

Quantitative arteriography of apparently normal coronary segments with nearby or distant disease suggests presence of occult, nonvisualized atherosclerosis.

OBJECTIVES: The aim of this study was to evaluate, using quantitative arteriography, whether the diameter of visually normal coronary segments might be influenced by the relative proximity of visually apparent disease. BACKGROUND: Severity of coronary artery lesions is commonly referenced against a presumed normal nearby coronary segment with the presumption that visually smooth segments are relatively free of atherosclerotic disease. METHODS: Angiograms from 136 male patients with focal coronary disease were examined, and visually normal segments in the proximal portions of the major vessels were identified for measurement of mean segment diameters. Normal segments with immediately adjacent disease were compared with normal segments with distal disease in the same vessel and compared with normal segments in vessels for which the only other visible disease was in distant vessels. Angiograms with entirely normal findings from 26 age-matched men with atypical chest pain were used as controls. Segments were measured after nitroglycerin administration by means of computer-assisted quantitation. RESULTS: Mean diameters of visually normal segments with distant disease were smaller than those of control segments (p < 0.05). Normal left main and proximal left anterior descending coronary artery segments in patients with disease within the same vessel were significantly smaller than normal segments in patients with distant disease (p < 0.05). Normal segments with immediately adjacent disease had smaller mean diameters than normal segments with distal disease in the same vessel (p < 0.05). CONCLUSIONS: Visually normal coronary segments have progressively smaller lumen diameters, depending on the relative proximity of visible disease. Measurement of percent stenosis on the basis of the diameter of apparently normal adjacent reference segments can result in underestimation of coronary lesion severity.

Dynamics of normal and ischemic canine papillary muscles.

This investigation was designed to elucidate the dynamics of the left ventricular (LV) papillary muscles. Miniature tantalum myocardial markers were placed on the tip and base of each papillary muscle in six dogs. Markers were also implanted into the LV myocardium to define two orthogonal equatorial diameters and the long-axis dimension. Two weeks later, after recovery from thoracotomy, markers were visualized by biplane fluoroscopy, and video images were recorded during control conditions, after autonomic blockade, after inotropic stimulation with calcium, after methoxamine infusion (to increase afterload), and after blood volume augmentation (to increase preload). Two days later, radiographic recordings were made before and after occlusion of the left circumflex coronary artery. Computer-aided analysis of the video recordings was used to determine three-dimensional coordinates of the markers. It was found that before circumflex coronary occlusion, the dynamics of both papillary muscles closely mimicked the dynamics of the LV as a whole. The papillary muscles shortened during ejection and lengthened during diastole. Their lengths changed minimally during the isovolumic periods, and this behavior was not altered by any of the interventions except coronary occlusion. During circumflex coronary artery occlusion, the ischemic posterior papillary muscle lengthened during isovolumic contraction and most of ejection and shortened only when LV pressure began to fall. Hence, we believe that previous studies demonstrating papillary muscle lengthening during isovolumic contraction and shortening during isovolumic relaxation may have been confounded by coexistent myocardial ischemia or stunning.

External beam irradiation inhibits neointimal hyperplasia following balloon angioplasty.

Restenosis is a serious problem limiting the long-term efficacy of percutaneous transluminal coronary angioplasty. Neointimal smooth muscle proliferation is the major process underlying restenosis. The objective of this study was to investigate the effects of external irradiation on neointimal hyperplasia following balloon angioplasty. We examined the ability of external X-ray irradiation to inhibit intimal hyperplasia following balloon angioplasty in a non-atherosclerotic rabbit model. Baseline quantitative angiography (day 0) was performed in all rabbits and balloon angioplasty was performed in the right (control) and the left iliac arteries. Five days after balloon angioplasty, the left iliac in each rabbit was irradiated with either 600 cGy (n = 5) or 1200 cGy (n = 5). Twenty-eight days following angioplasty final angiography was performed. All rabbits were sacrificed, and the iliac arteries were fixed for morphometric measurements. Comparison of baseline and final angiographic measurements revealed a significant decrease in average and minimum lumen dimensions for both control and irradiated segments (600 and 1200 cGy) [average: P (baseline vs. final) 0.008 (control), 0.001 (600 cGy); 0.05 (control), 0.007 (1200 cGy)]. Morphometric analysis showed no difference in neointimal cross-sectional area between control (0.29 +/- 0.05 mm2) and 600 cGy irradiated segments (0.32 +/- 0.07 mm2) (P = 0.82). However, there was a statistically significant reduction in neointimal hyperplasia in the 1200 cGy irradiated segments (0.09 +/- 0.02 mm2) compared to control (0.23 +/- 0.06 mm2, P = 0.02). There was no significant difference in medial cross-sectional area between control and irradiated segments (600 and 1200 cGy). We conclude that in this model, external beam X-ray irradiation (1200 cGy) was successful in reducing neointimal proliferation after balloon angioplasty. Whether or not this approach can be used successfully to inhibit restenosis in the clinical setting requires further investigation.

Cell proliferation after balloon injury of iliac arteries in the cholesterol-fed New Zealand White rabbit.

Acute mechanical injury of an artery results in neointimal hyperplasia that is due at least in part to cell proliferation within the vessel wall. The purpose of this study was to quantify cell proliferation activity in the iliac artery of New Zealand White rabbits after balloon injury and cholesterol feeding. Retrograde pullback balloon injury of iliac arteries was performed, and the animals were then fed a 2% cholesterol diet. At intervals from day 1 through day 35 postinjury, iliac arteries were obtained for histological analysis. Intimal and medial areas were measured morphometrically. Total number of cells within the intima and media was counted. Smooth muscle cell-predominant or macrophage-predominant regions of the intima and media were identified using HHF-35 and RAM-11 immunocytochemical markers, respectively. Number of cells in the proliferative phase of the cell cycle was measured by using the proliferating cell nuclear antigen and bromodeoxyuridine techniques. Thirty-one arteries from 16 rabbits were available for analysis. Total number of cells and number of cells per square millimeter within the media did not change significantly from day 1 through day 35 postinjury. Total number of cells within the intima increased significantly, but the number of cells per square millimeter of intima decreased significantly during the same time period. Proliferative activity was identified in the media between days 3 and 35 with peak activity at day 3 postinjury. Proliferative activity in the intima was present in all specimens from day 8 through day 35. Proliferative activity was present in both HHF-35- and RAM-11-predominant regions of the intima.(ABSTRACT TRUNCATED AT 250 WORDS)

Local infusion balloon angioplasty to obviate restenosis compared with conventional balloon angioplasty in an experimental model of atherosclerosis.

Balloon angioplasty is an accepted treatment for arterial obstruction; however, a substantial percentage of initially successfully treated lesions recur in the first 4 to 6 months. There is increasing interest in local treatment of lesions undergoing angioplasty to prevent restenosis, and an infusion catheter has been developed for this purpose. This study compared infusion balloon angioplasty by means of saline solution with conventional balloon angioplasty in atherosclerotic iliac arteries of 18 cholesterol-fed New Zealand white rabbits. Values for minimum stenosis diameter assessed angiographically immediately after maximum infusion balloon angioplasty (2.1 +/- 0.6 mm) and after conventional balloon angioplasty (2.3 +/- 0.3 mm, p = NS) were similar. In follow-up studies up to 5 weeks after angioplasty, the angiographic minimum stenosis diameter remained similar in the two treatment groups, but the histologically assessed intimal area was greater after infusion angioplasty (1.54 +/- 0.92 mm vs 1.02 +/- 0.75 mm in conventionally treated arteries, p = 0.0001). Infusion balloon angioplasty merits further evaluation as a treatment strategy for the simultaneous dilatation of atherosclerotic lesions with delivery of therapeutic agents to minimize restenosis.

Dose-related efficacy and bleeding complications of double-chain tissue plasminogen activator in acute myocardial infarction. The Wellcome Tissue Plasminogen Activator Study Group.

Although the efficacy of recombinant tissue-type plasminogen activator (rt-PA) in acute myocardial infarction has been demonstrated, little formal dose-ranging information is available. This study examined the use of duteplase, the double-chain rt-PA subsequently used in the Third International Study of Infarct Survival, in a multicenter trial of 267 patients with evolving acute myocardial infarction assigned to receive 1 of 6 weight-adjusted doses. The primary end point was infarct vessel patency after 90 minutes of drug infusion. Patency was defined as Thrombolysis in Myocardial Infarction trial grade 2 or 3 perfusion, and was determined by an independent core laboratory masked to treatment assignment. Patency was present in 48% of patients receiving the lowest dose range and 78% of those receiving the highest, with an association between thrombolytic dose and patency (p = 0.009). The frequency of serious bleeding complications also correlated with the total dose of rt-PA infused (p = 0.003). Bleeding complications were primarily related to instrumentation; blood loss requiring transfusion or otherwise deemed clinically significant occurred in 12% of patients (central nervous system hemorrhage occurred in 1.1%). Thus, higher doses of rt-PA are associated both with increased efficacy and increased risk of serious bleeding complications. Weight-adjusted dosing may provide an optimal risk-benefit ratio for thrombolysis during acute myocardial infarction.

Time course and cellular characteristics of the iliac artery response to acute balloon injury. An angiographic, morphometric, and immunocytochemical analysis in the cholesterol-fed New Zealand white rabbit.

Evaluation of the response of the arterial vessel wall to acute arterial injury in experimental models has taken on substantial importance because of an increasing interest in angioplasty treatment of human atherosclerotic lesions. In this study, the response of normal arterial vessels to acute balloon injury was studied in 45 iliac artery segments from 24 New Zealand White rabbits fed a 2% cholesterol diet. At specified time points between 1 and 41 days after the initial balloon pullback injury, the iliac arteries were analyzed by angiographic, morphometric, and immunocytochemical techniques. Angiographic measurements indicated progressive compromise of the iliac artery lumen with increasing duration of time from injury. Morphometric measurements showed that intimal area increased from 0.004 +/- 0.01 mm2 3 days after injury to 1.15 +/- 0.30 mm2 34-41 days after injury. Cell line-specific immunocytochemical analysis identified the macrophage as a prominent component of the earliest intimal cellular infiltrate. Smooth muscle cells appeared within the intima 7-9 days after injury. As the intima increased in area, macrophages predominated along the internal elastic lamina aspect of the intimal lesion while smooth muscle cells occupied the portion of the intima adjacent to the lumen. In summary, retrograde balloon pullback injury followed by cholesterol feeding results in progressive arterial luminal narrowing due to a progressively enlarging intimal cellular infiltrate. The temporal and spatial contributions of smooth muscle cell and macrophage components of the developing intimal cellular infiltrate have been characterized.

Coronary angioplasty in cardiac transplant patients. Results of a multicenter study.

BACKGROUND: Accelerated allograft atherosclerosis is the main cause of death of cardiac transplant recipients after the first year after transplantation. Because no medical therapy is known to prevent or retard graft atherosclerosis and transplantation is associated with a shortened allograft survival, alternative, palliative therapy with percutaneous transluminal coronary angioplasty (PTCA) has been attempted. Because no single medical center has performed angioplasty in a large number of cardiac transplant recipients, representatives of 11 medical centers retrospectively analyzed their complete experience of coronary angioplasty in cardiac transplant patients to determine the safety, efficacy, limitations, and long-term outcome of angioplasty in allograft coronary vascular disease. METHODS AND RESULTS: Thirty-five patients underwent 51 angioplasty procedures for 95 lesions 46 +/- 5 months (mean +/- SEM) after transplantation. The primary indications for angioplasty included angiographic coronary disease in 22 cases (43%) and noninvasive evidence of ischemia in 18 procedures (35%). Angiographic success, defined as less than or equal to 50% post-PTCA stenosis, occurred in 88 of 95 lesions (93%). Mean pre-PTCA stenosis was 83 +/- 1.1%; mean post-PTCA stenosis was 29 +/- 2.1% (p less than 0.0001). Periprocedural complications included myocardial infarction and late in-hospital death in one patient and three groin hematomas. Twenty-three of the 35 patients (66%) had no major adverse outcome such as death, retransplantation, or myocardial infarction at 13 +/- 3 months after angioplasty. Four patients died less than 6 months after angioplasty, and four died more than 6 months after angioplasty (range, 6-23 months). Two patients had retransplantation 2 months after PTCA, and one patients had retransplantation 18 months after angioplasty. CONCLUSIONS: Coronary angioplasty may be applied in selected cardiac transplant recipients with comparable success and complication rates to routine angioplasty. Whether angioplasty prolongs allografts survival remains to be determined by a prospective, controlled trial.

Nitroglycerin-induced coronary vasodilation in cardiac transplant recipients. Evaluation with in vivo intracoronary ultrasound.

BACKGROUND: Coronary artery vasomotion is altered after cardiac transplantation. The impact of accelerated transplant coronary atherosclerosis and myocardial rejection on vasomotion is not well understood. Intravascular ultrasound is a new imaging method with the ability to study real-time changes in coronary artery dimensions. METHODS AND RESULTS: Epicardial coronary artery response to nitroglycerin was studied in 32 cardiac transplant recipients (age, 47 +/- 11 years) 3 weeks to 10 years after transplantation with intracoronary ultrasound. Cross-sectional luminal area and diameter were measured at a fixed position in the left anterior descending artery immediately before and every 30 seconds for 5 minutes after 0.4 mg of sublingual nitroglycerin. Cross-sectional area increased from a baseline of 13.1 +/- 3.9 mm2 to 15.8 +/- 3.9 mm2 at maximal vasodilation; luminal diameter increased from 4.0 +/- 0.6 mm to 4.5 +/- 0.6 mm. This increase reached statistical significance (p less than 0.001) at 1.5 minutes after administration of nitroglycerin; mean maximum increase occurred at 4.5 minutes (24% for cross-sectional area and 11% for luminal diameter). Patients with biopsy-proven mild or moderate concurrent rejection had a significantly blunted vasodilatory response versus the nonrejection group (9% versus 27% for cross-sectional area, p less than 0.04), although a vasodilatory effect was still present. Nitroglycerin response was well preserved in patients up to 10 years after transplantation; however, there was a trend toward a decreased response in patients studied immediately after transplantation (21% versus 29%, p = 0.37). Coronary intimal thickness, as measured by ultrasound, had no impact on the vasodilatory response (R = 0.23, p = 0.34). CONCLUSIONS: Vasodilatory response to nitroglycerin in cardiac transplant recipients is attenuated during episodes of cardiac rejection. This response is preserved in long-term survivors and is independent of the degree of intimal thickening. Intravascular ultrasound provides a new method to document real-time epicardial coronary vasomotion.

Determinants of normal coronary artery dimensions in humans.

BACKGROUND: Studies of normal human coronary dimensions have been performed primarily in postmortem hearts. We evaluated the influence of age, body habitus, and regional myocardial mass on coronary dimensions in living patients with normal coronary vessels. METHODS AND RESULTS: Arteriographically normal coronary angiograms were analyzed from the following groups of subjects: group 1 (age, 15-34 years) consisted of 30 post-cardiac transplant patients with donor hearts from male subjects aged 15-34 years, group 2 (age, 35-54 years) consisted of 12 post-cardiac transplant patients with donor hearts from male subjects aged 35-54 years and 26 male subjects investigated for atypical chest pain, and group 3 (age, 55-74 years) consisted of 26 male subjects investigated for atypical chest pain. All angiograms were performed after sublingual nitroglycerin. Measurements of the dimensions of the left main, proximal left anterior descending, proximal left circumflex, and proximal right coronary arteries were made using a computer-assisted edge-detection algorithm. The regional myocardial mass supplied by each vessel was derived from echocardiographically derived total left ventricular mass and a semiquantitative angiographic territory scoring system based primarily on the number and length of its terminal nutrient branches. CONCLUSIONS: Linear regression analysis showed that coronary vessel cross-sectional area and total coronary cross-sectional area increase with regional myocardial mass and decrease linearly with age. Multivariate regression analysis revealed that regional myocardial mass and age were independent predictors of cross-sectional area for each vessel and for the total coronary cross-sectional area. We speculate that age-related decline in physical activity, in part, may be responsible.

Intravascular ultrasound imaging of angiographically normal coronary arteries: an in vivo comparison with quantitative angiography.

Intravascular ultrasound, a new technique for real-time two-dimensional visualization of arteries and veins, delineates vessel wall morphology and measures luminal dimensions. This imaging method has been validated with in vitro systems and in peripheral vessels, but there are few in vivo coronary artery studies. Twenty cardiac transplant recipients with no angiographic coronary artery disease were scanned with a 30-MHz intravascular ultrasound catheter from the left main coronary ostium to the mid-left anterior descending coronary artery. Simultaneous angiographic measurements were performed at 76 sites. Ultrasound end-diastolic diameters in two perpendicular axes were 3.8 +/- 0.9 and 3.9 +/- 0.6 mm, respectively, and mean diameter derived from an area determined by planimetry was 3.9 +/- 0.9 mm. Angiographic coronary artery diameters measured with a computer-assisted edge detection system perpendicular to the long axis of the vessel and to the long axis of the catheter were 3.4 +/- 0.8 and 3.6 +/- 0.8 mm, respectively. Luminal diameters measured with the two imaging systems correlated closely, with an r value of 0.86 when ultrasound was compared with the angiographic diameter measured perpendicular to the vessel and 0.88 when compared with the angiographic diameter measured perpendicular to the imaging catheter. Eighty-three percent of the ultrasound-measured diameters were above the line of identity when compared with the simultaneous angiographic measurement. The more the imaging catheter deviated from the long axis of the vessel, the greater was the discrepancy between the ultrasound and angiographic measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

New technologies for the treatment of obstructive arterial disease.

The well-known limitations of balloon angioplasty include unpredictable abrupt closure, chronic total occlusion, diffuse disease, and restenosis, among other factors. These limitations have prompted the development of new technologic approaches to angioplasty including laser applications for plaque ablation, mechanical device applications for plaque removal/debridement, and stent devices for structural maintenance of vascular lumen patency. Devices which directly apply laser energy for ablation of plaque material include a balloon-centered laser angioplasty system, excimer laser ablation catheter systems, and a fluorescence-guided spectral feedback laser system. Experience with these devices indicates that plaque can be successfully ablated by using laser energy. Vessel perforation and dissection are complications reported with these devices and the effects of laser angioplasty on restenosis remain unclear. Indirect application of laser energy has been tested by using a "hot tip" catheter and a laser balloon angioplasty system. Although the hot tip device has received FDA approval for use in peripheral arteries, it appears to have very limited applications in the coronary arteries. Laser balloon angioplasty appears to be beneficial in the setting of threatened acute closure; the device continues to be evaluated for potential beneficial impact on restenosis. Mechanical atherectomy catheters are designed to remove atherosclerotic plaque from the arterial system and include the AtheroCath, the Transluminal Extraction Catheter (TEC), and the Pullback Atherectomy Catheter (PAC). The Rotablator is an atheroablation device which debrides the obstructing plaque material with distal embolization of the particulate debris. Successful removal/debridement of atherosclerotic plaque has been demonstrated with the AtheroCath, Rotablator, and the TEC device. Pre-clinical studies demonstrate successful removal of plaque material with the PAC device. Despite the theoretic advantage of removing plaque material when performing angioplasty with these devices, there has been little or no reduction in restenosis rates based on a significant experience with the AtheroCath and the Rotablator. Intravascular stent devices including one self-expanding device design and two balloon-expandable device designs have been employed successfully in the elective setting to treat recurrent restenosis lesions. Two of the devices have been successfully tested in the setting of threatened acute closure. Early follow-up studies suggest some improvement in restenosis rates in certain clinical settings following intravascular stenting. Acute and subacute thrombosis remain substantial problems for stent devices and very aggressive anticoagulation regimens are necessary to minimize the adverse events. In summary, a number of a new technologic approaches for treatment of atherosclerotic lesions have been developed and are undergoing significant clinical evaluation.(ABSTRACT TRUNCATED AT 400 WORDS)