Spontaneous regression of restenosis: an angiographic study

Transforming growth factor-β and atherosclerosis: interwoven atherogenic and atheroprotective aspects

Age-related progression of cardiovascular disease is by far the largest health problem in the US and involves vascular damage, progressive vascular fibrosis and the accumulation of lipid-rich atherosclerotic lesions. Advanced lesions can restrict flow to key organs and can trigger occlusive thrombosis resulting in a stroke or myocardial infarction. Transforming growth factor-beta (TGF-β) is a major orchestrator of the fibroproliferative response to tissue damage. In the early stages of repair, TGF-β is released from platelets and activated from matrix reservoirs; it then stimulates the chemotaxis of repair cells, modulates immunity and inflammation and induces matrix production. At later stages, it negatively regulates fibrosis through its strong antiproliferative and apoptotic effects on fibrotic cells. In advanced lesions, TGF-β might be important in arterial calcification, commonly referred to as "hardening of the arteries". Because TGF-β can signal through multiple pathways, namely the SMADs, a MAPK pathway and the Rho/ROCK pathways, selective defects in TGF-β signaling can disrupt otherwise coordinated pathways of tissue regeneration. TGF-β is known to control cell proliferation, cell migration, matrix synthesis, wound contraction, calcification and the immune response, all being major components of the atherosclerotic process. However, many of the effects of TGF-β are essential to normal tissue repair and thus, TGF-β is often thought to be "atheroprotective". The present review attempts to parse systematically the known effects of TGF-β on both the major risk factors for atherosclerosis and to isolate the role of TGF-β in the many component pathways involved in atherogenesis.

Omega 3 fatty acids for prevention and treatment of cardiovascular disease

BACKGROUND

It has been suggested that omega 3 (W3, n-3 or omega-3) fats from oily fish and plants are beneficial to health.

OBJECTIVES

To assess whether dietary or supplemental omega 3 fatty acids alter total mortality, cardiovascular events or cancers using both RCT and cohort studies.

SEARCH STRATEGY

Five databases including CENTRAL, MEDLINE and EMBASE were searched to February 2002. No language restrictions were applied. Bibliographies were checked and authors contacted.

SELECTION CRITERIA

RCTs were included where omega 3 intake or advice was randomly allocated and unconfounded, and study duration was at least six months. Cohorts were included where a cohort was followed up for at least six months and omega 3 intake estimated.

DATA COLLECTION AND ANALYSIS

Studies were assessed for inclusion, data extracted and quality assessed independently in duplicate. Random effects meta-analysis was performed separately for RCT and cohort data.

MAIN RESULTS

Forty eight randomised controlled trials (36,913 participants) and 41 cohort analyses were included. Pooled trial results did not show a reduction in the risk of total mortality or combined cardiovascular events in those taking additional omega 3 fats (with significant statistical heterogeneity). Sensitivity analysis, retaining only studies at low risk of bias, reduced heterogeneity and again suggested no significant effect of omega 3 fats. Restricting analysis to trials increasing fish-based omega 3 fats, or those increasing short chain omega 3s, did not suggest significant effects on mortality or cardiovascular events in either group. Subgroup analysis by dietary advice or supplementation, baseline risk of CVD or omega 3 dose suggested no clear effects of these factors on primary outcomes. Neither RCTs nor cohorts suggested increased relative risk of cancers with higher omega 3 intake but estimates were imprecise so a clinically important effect could not be excluded.

REVIEWERS' CONCLUSIONS

It is not clear that dietary or supplemental omega 3 fats alter total mortality, combined cardiovascular events or cancers in people with, or at high risk of, cardiovascular disease or in the general population. There is no evidence we should advise people to stop taking rich sources of omega 3 fats, but further high quality trials are needed to confirm suggestions of a protective effect of omega 3 fats on cardiovascular health. There is no clear evidence that omega 3 fats differ in effectiveness according to fish or plant sources, dietary or supplemental sources, dose or presence of placebo.

Quantitative angiographic and intravascular ultrasound study >5 years after directional coronary atherectomy

Aggressive and optimal directional coronary atherectomy (DCA) using intravascular ultrasound (IVUS) guidance provides favorable outcomes within 1 year. However, no previous data are available on the changes that occur in target lesions for the long term after stand-alone DCA. This study's aim evaluates, using quantitative angiography and intravascular ultrasonography, the natural history of changes that occur in target lesions between short- (about 6 months) and long-term (>5 years) follow-up angiography after stand-alone DCA. Of 186 patients (221 lesions) with successful stand-alone DCA, 48 patients (53 lesions) underwent revascularization within 6 months, and 14 patients subsequently died, leaving a study population of 124 patients (154 lesions). Complete quantitative coronary angiography (QCA) was obtained in 91 patients (101 lesions) and complete serial IVUS assessment was obtained for 38 lesions before and after intervention and during follow-up. From short- to long-term follow-up angiography, the minimal luminal diameter significantly increased (from 2.12 to 2.56 mm; p <0.0001); lesion subgroups with >30% diameter stenosis at short-term follow-up angiography showed significant late regression as assessed by QCA. Serial IVUS assessment revealed that the vessel cross-sectional area did not change (from 17.3 to 17.4 mm(2); p = NS); however the lumen cross-sectional area significantly increased (from 7.3 to 9.5 mm(2); p <0.0001) due to the reduction of plaque plus media cross-sectional area (from 10.0 to 7.9 mm(2); p <0.0001). The change in lumen cross-sectional area correlated with the change in plaque plus media cross-sectional area (r = -0.686, p <0.0001). Target lesions show late regression due to plaque reduction at >5 years after stand-alone DCA.

The Drug-Eluting Stent Information Gap

Drug-eluting stents are quickly replacing bare-metal stents as the arterial revascularization device of choice. Because nearly all the information we have about patient outcomes with drug-eluting stents is from trials designed for US Food and Drug Administration approval, we are missing some of the information critical to a more comprehensive understanding of how these new devices will perform at the population level.

Patient care before and after percutaneous coronary artery interventions

Care of the patient before and after percutaneous coronary interventions has changed largely because of the increased use of stents. Important patient management issues include the evaluation of chest pain after the procedure, recognition of acute vessel closure during the periprocedural period, management of the vascular access site, and prevention of contrast-induced renal dysfunction. Risk factor modification and drug therapies are important interventions for the secondary prevention of coronary events. Functional testing has a meaningful role in the evaluation of some patients after coronary intervention. It is important for the specialist in internal medicine to have a firm working knowledge of the various aspects of patient care before and after these procedures because their role in the management of these patients is increasing.

Randomized trial comparing intravenous nitroglycerin and heparin for treatment of unstable angina secondary to restenosis after coronary artery angioplasty

BACKGROUND

The treatment of unstable angina targets the specific pathophysiological thrombotic process at the site of the active culprit lesion. In unstable angina due to a restenotic lesion, smooth muscle cell proliferation and increased vasoreactivity may play a more important role than thrombus formation. Therefore, the relative benefits of nitroglycerin and heparin might differ in unstable angina associated with restenosis compared with classic unstable angina.

METHODS AND RESULTS

We randomized 200 patients hospitalized for unstable angina within 6 months after angioplasty (excluding those with intracoronary stents) to double-blind administration of intravenous nitroglycerin, heparin, their combination, or placebo for 63+/-30 hours. Recurrent angina occurred in 75% of patients in the placebo and heparin-alone groups, compared with 42.6% of patients in the nitroglycerin-alone group and 41.7% of patients in the nitroglycerin-plus-heparin group (P<0.003). Refractory angina requiring angiography occurred in 22.9%, 29.2%, 4. 3%, and 4.2% of patients, respectively (P<0.002). The odds ratios for being event free were 0.24 (95% CI, -0.13 to 0.45, P=0.0001) for nitroglycerin versus no nitroglycerin and 0.98 (95% CI, -0.55 to 1. 73, P=NS) for heparin versus no heparin. No patient died or suffered myocardial infarction.

CONCLUSIONS

Intravenous nitroglycerin is highly effective in preventing adverse ischemic events (recurrent or refractory angina) in patients with unstable angina secondary to restenosis, whereas heparin has no effect.

TGF-betas and TGF-beta receptors in atherosclerosis

Based on diverse evidence in animals and humans, it has been hypothesized that atherosclerosis, and other injury-induced hyperplasias such as restenosis, may result from a failure in endogenous inhibitory systems that normally limit wound repair and induce regression of wound repair cells. A key defect in one of these inhibitory pathways, the TGF-beta system, has been identified and characterized in both animal models and in human lesions and lesion-derived cells. Cells derived from human lesions are resistant to the antiproliferative and apoptotic effects of TGF-beta, while their normal counterparts from the vascular media are potently inhibited and killed. Both cell types increase PAI-1 production, switch actin phenotypes in response to TGF-beta1, and produce similar levels of TGF-beta activity. Membrane cross-linking of (125)I-TGF-beta1 indicates that normal human SMC express Type I, II and III receptors. The Type II receptor is strikingly decreased in lesion cells, with little change in the Type I or III receptors. RT-PCR confirmed that the Type II TGF-beta1 receptor mRNA is reduced in lesion cells. Subsequent analysis of human lesion vs normal tissues confirmed that the Type I receptor was consistently present in the lesion, while the Type II receptor was much more variable, and commonly absent in both coronary artery and carotid artery lesions. Transfection of the Type II receptor into lesion cells partially restores the growth inhibitory response to TGF-beta1, implying that signaling remains intact. A subset of patients, and cells derived from their lesions, exhibit acquired mutations in the Type II receptor that would explain their resistance, though the majority of cells are resistant without obvious mutational defects. Thus, it is currently being tested whether transcriptional defects or abnormalities in receptor processing may explain the low levels of the Type II receptor. Because TGF-beta1 is overexpressed in fibroproliferative vascular lesions, receptor-negative cells would be allowed to grow in a slow, but uncontrolled fashion, while overproducing extracellular matrix components.

Cost-efficacy modeling of functional testing with perfusion imaging to detect asymptomatic restenosis following percutaneous transluminal coronary angioplasty

The objective of this study was to perform a theoretical cost-efficacy analysis on the use of routine functional testing with perfusion imaging to identify patients with asymptomatic restenosis following percutaneous transluminal coronary angioplasty (PTCA) procedures. Approximately 50% of patients with restenosis following PTCA are asymptomatic. Routine functional testing is commonly performed at 3 to 6 months to identify these patients. The cost-efficacy associated with this strategy is unknown. Theoretical models were constructed based on assumed costs for functional testing (U.S. $1,300) and coronary angiography (U.S. $3,000). Restenosis rates were assumed to be 40%, and half of patients with restenosis were assumed to be asymptomatic. To provide a range of costs to identify a patient with asymptomatic restenosis, three scenarios were constructed based on the diagnostic test characteristics of functional testing. Sensitivity analyses were performed using a range of costs for functional testing, restenosis rates, and proportion of patients with restenosis who are asymptomatic. Depending on the diagnostic accuracy of functional testing, it costs $8,200 to $22,400 to identify an asymptomatic patient with restenosis following PTCA. The cost to identify a patient with asymptomatic restenosis varies inversely with the rates of restenosis. When restenosis rates are < 20%, the cost to identify a patient with asymptomatic restenosis exceeds $10,000. Similarly, the cost to identify a patient with asymptomatic restenosis increases when the proportion of patients with asymptomatic restenosis decreases. The cost, associated with the use of routine functional testing for the identification of asymptomatic patients with restenosis appears exorbitant. However, a formal study is warranted to determine the cost-efficacy of such a strategy. Cathet. Cardiovasc. Intervent. 48:352-356, 1999.

The expression of TGF-beta receptors in human atherosclerosis: evidence for acquired resistance to apoptosis due to receptor imbalance

The degree of cellularity in vascular lesions is determined by the balance between the migration and proliferation of cells relative to their rate of egress and apoptosis. Transforming growth factor-beta(1) can act as a potent antiproliferative and apoptotic factor for proliferating vascular cells. Our laboratory has previously identified cells cultured from human vascular lesions that are resistant to the antiproliferative effect of TGF-beta(1) due to an acquired mutation in the Type II receptor for TGF-beta(1). In the present studies, the expression of the Type I and II receptors in coronary and carotid atherosclerotic lesions was analysed by immunostaining, RT-PCR, and in situ RT-PCR. Levels of the Type I and Type II receptors varied widely within lesions, with the highest levels in the fibrous cap and at discrete foci within the lesion. Regions of smooth muscle-like cells (SMC) were commonly found that were Type I positive but Type II receptor negative. In 43 cell lines cultured from 126 human lesions, 84% of the lesion-derived cell (LDC) cultures exhibited functional resistance to the antiproliferative effect of TGF-beta(1). This resistance was conferred against TGF-beta(1), TGF-beta(2), and TGF- beta(3), but not interferon-gamma or mimosine. While normal SMC exhibited a four-fold increase in the rate of apoptosis after TGF- beta(1) treatment, most LDC were resistant to apoptosis in response to TGF-beta(1). Resistant cells exhibited selective loss of Type II receptor expression, and retroviral transfection of Type II receptor cDNA partially corrected the functional deficit. Thus, resistance to apoptosis may lead to the slow proliferation of resistant cell subsets, thereby contributing to the progression of atherosclerotic and restenotic lesions.

Glucocorticoid resistance caused by reduced expression of the glucocorticoid receptor in cells from human vascular lesions

Mechanisms that control the balance between cell proliferation and death are important in the development of vascular lesions. Rat primary smooth muscle cells were 80% inhibited by low microgram doses of hydrocortisone (HC) and 50% inhibited by nanogram concentrations of transforming growth factor-beta1 (TGF-beta1), although some lines acquired resistance in late passage. However, comparable doses of HC, or TGF-beta1, failed to inhibit most human lesion-derived cell (LDC) lines. In sensitive LDC, HC (10 microg/mL) inhibited proliferation by up to 50%, with obvious apoptosis in some lines, and TGF-beta1 inhibited proliferation by more than 90%. Collagen production, as measured by [3H]proline incorporation or RIA for type III pro-collagen, was either unaffected or increased in the LDCs by HC. These divergent responses between LDC lines were partially explained by the absence of the glucocorticoid receptor (GR) and heat shock protein 90 mRNA in 10 of 12 LDC lines, but the presence of the mineralocorticoid receptor and 11beta-hydroxysteroid dehydrogenase type II. Western blot analysis confirmed the absence of the GR protein in cells lacking GR mRNA. Immunohistochemistry of human carotid lesions showed high levels of GR in the tunica media, but large areas lacking GR in the fibrous lesion. Considering the absence of the GR in most lines, the effects of HC may be elicited through the mineralocorticoid receptor. Functional resistance to the antiproliferative and antifibrotic effects of HC may contribute to excessive wound repair in atherosclerosis and restenosis.

Outcome of target sites escaping high-grade (>70%) restenosis after percutaneous transluminal coronary angioplasty

This study examined the fate of target sites that escaped high-grade restenosis (> or = 70% diameter narrowing) after percutaneous transluminal coronary angioplasty. Although favorable long-term prognosis after successful percutaneous transluminal coronary angioplasty is well documented, little is known about the stability of target sites. Long-term follow-up (mean 6.5 years, range 1.0 to 12.0) was performed in 693 patients with 948 narrowings (stenosis <70% in diameter at follow-up coronary angiography). Among them, 249 patients (36%) with 303 target sites received late follow-up coronary angiography. The relation of target sites to the culprit lesions for coronary events or newly developed angina was angiographically reviewed and progression/regression was also examined, focusing on the target sites. Regression was observed in 16 of 255 target sites in subjects with <50% stenosis and in 21 of 48 sites in the group with midgrade stenosis of 50% to 69% luminal narrowing (16 of 255, 6.3% vs 21 of 48, 43.8%, p <0.001). Progression was observed in 33 and 4 sites (33 of 255, 12.9% vs 4 of 48, 8.3%; p = NS) in each group, respectively. The rest remained within the same range of stenosis. Culprit lesions for 2 acute myocardial infarctions, 7 unstable anginas, and 17 newly developed anginas were related to the original target sites. Three lesions developed in the midgrade stenosis group. Those 26 lesions were a component of 8.6% of 303 angiographically confirmed sites and 2.7% of total target sites. Target sites that escape high-grade restenosis frequently regress and become stable plaques and rarely trigger coronary events.

Adventitial vasa vasorum in balloon-injured coronary arteries: visualization and quantitation by a microscopic three-dimensional computed tomography technique

OBJECTIVES

The objective of this study was to examine the quantitative response of the adventitial vasa vasorum to balloon-induced coronary injury.

BACKGROUND

Recent attention has focused on the role of vasa vasorum in atherosclerotic and restenotic coronary artery disease. However, the three-dimensional anatomy of these complex vessels is largely unknown, especially after angioplasty injury. The purpose of this study was to visualize and quantitate three-dimensional spatial patterns of vasa vasorum in normal and balloon injured porcine coronary arteries. We also studied the spatial growth of vasa vasorum in regions of neointimal formation. A novel imaging technique, microscopic computed tomography, was used for these studies.

METHODS

Four pigs were killed 28 d after coronary balloon injury, and four pigs with uninjured coronary arteries served as normal controls. The coronary arteries were injected with a low-viscosity, radiopaque liquid polymer compound. Normal and injured coronary segments were scanned using a microscopic computed tomography technique. Three-dimensional reconstructed maximum intensity projection and voxel gradient shading images were displayed at different angles and voxel threshold values, using image analysis software. For quantitation, seven to 10 cross-sectional images (40 normal and 32 balloon injured cross-sections) were captured from each specimen at a voxel size of 21 microm.

RESULTS

Normal vasa vasorum originated from the coronary artery lumen, principally at large branch points. Two different types of vasa were found and classified as first-order or second-order according to location and direction. In balloon-injured coronary arteries, adventitial vasa vasorum density was increased (3.16+/-0.17/mm2 vs. 1.90+/-0.06/mm2, p = 0.0001; respectively), suggesting neovascularization by 28 d after vessel injury. Also, in these injured arteries, the vasa spatial distribution was disrupted compared with normal vessels, with proportionally more second-order vasa vasorum. The diameters of first-order and second-order vasa were smaller in normal compared with balloon-treated coronary arteries (p = 0.012 first-order; p < 0.001, second-order; respectively). The density of newly formed vasa vasorum was proportional to vessel stenosis (r = 0.81, p = 0.0001). Although the total number of vasa was increased after injury, the total vascular area comprised of vasa was significantly reduced in injured vessels compared with normals (3.83+/-0.20% to 5.42+/-0.56%, p = 0.0185).

CONCLUSIONS

Adventitial neovascularization occurs after balloon injury. The number of new vessels is proportional to vessel stenosis. These findings may hold substantial implications for the therapy of vascular disease and restenosis.

Sustained benefit of stenting chronic coronary occlusion: long-term clinical follow-up of the Stenting in Chronic Coronary Occlusion (SICCO) study

OBJECTIVES

This study assessed the long-term clinical outcome of stenting chronic occlusions.

BACKGROUND

In the Stenting in Chronic Coronary Occlusion (SICCO) study, patients were randomized to additional stent implantation (n = 58) or not (n = 59) after successful recanalization and dilation of a chronic coronary occlusion. Palmaz-Schatz stents were used with full anticoagulation. The previously published 6-month angiographic follow-up results showed reduction of the restenosis rate from 74% to 32%.

METHODS

The primary end point was the occurrence of major adverse cardiac events (cardiac death, lesion-related acute myocardial infarction, repeat lesion-related revascularization or angiographic documentation of reocclusion).

RESULTS

Late clinical follow-up was obtained in all patients at 33 +/- 6 months. Major adverse cardiac events occurred in 14 patients (24.1%) in the stent group compared with 35 patients (59.3%) in the percutaneous transluminal coronary angioplasty (PTCA) group (odds ratio 0.22, 95% confidence interval 0.10 to 0.49, p = 0.0002). Target vessel revascularization (including failed PTCA attempts) was performed in 24% of the stent group and in 53% of the PTCA group (p = 0.002). There were no events in the stent group after 8 months, whereas events continued to occur in the PTCA group. By multivariate analysis, allocation to the PTCA group, left anterior descending coronary artery lesion and lesion length were significantly related to the development of major adverse cardiac events.

CONCLUSIONS

These data demonstrate the long-term safety and clinical benefit of stenting recanalized chronic occlusions. There is a continued risk of late clinical events related to nonstented lesions. Implantation of an intracoronary stent should therefore be considered after successful opening of a chronic coronary occlusion.

Genomic instability in the type II TGF-beta1 receptor gene in atherosclerotic and restenotic vascular cells

Cells proliferating from human atherosclerotic lesions are resistant to the antiproliferative effect of TGF-beta1, a key factor in wound repair. DNA from human atherosclerotic and restenotic lesions was used to test the hypothesis that microsatellite instability leads to specific loss of the Type II receptor for TGF-beta1 (TbetaR-II), causing acquired resistance to TGF-beta1. High fidelity PCR and restriction analysis was adapted to analyze deletions in an A10 microsatellite within TbetaR-II. DNA from lesions, and cells grown from lesions, showed acquired 1 and 2 bp deletions in TbetaR-II, while microsatellites in the hMSH3 and hMSH6 genes, and hypermutable regions of p53 were unaffected. Sequencing confirmed that these deletions occurred principally in the replication error-prone A10 microsatellite region, though nonmicrosatellite mutations were observed. The mutations could be identified within specific patches of the lesion, while the surrounding tissue, or unaffected arteries, exhibited the wild-type genotype. This microsatellite deletion causes frameshift loss of receptor function, and thus, resistance to the antiproliferative and apoptotic effects of TGF-beta1. We propose that microsatellite instability in TbetaR-II disables growth inhibitory pathways, allowing monoclonal selection of a disease-prone cell type within some vascular lesions.

Restenosis or rapid progression in non-dilated sites are not predictors of late spontaneous coronary events

The present study was designed to assess the prognostic value of clinical and angiographic factors, and especially restenosis or rapid progression in non-dilated sites, on major spontaneous coronary events at long-term follow-up after a first successful coronary angioplasty performed for angina pectoris. A second aim was to assess the prognostic factors and especially restenosis in asymptomatic patients after angioplasty. The first 352 consecutive patients undergoing a successful coronary angioplasty were selected and followed-up. The following variables: age, sex, unstable angina, previous myocardial infarction, diabetes, hypercholesterolemia, tobacco consumption, hypertension, fibrinogen, coronary extent, single or multiple dilatation, restenosis, new progression, clinical deterioration of anginal status just before angiographic restudy or asymptomatic status were subjected to a stepwise regression analysis. Restenosis (a loss of 30% in diameter and/or a return to a >50% stenosis) and progression in non-dilated segments (a 20% reduction in diameter) were assessed by a computer-assisted method. Cardiac death, new myocardial infarction or new unstable angina, at long-term follow-up after angiographic restudy, were regarded as spontaneous coronary events and pooled in a single dependent variable. Thus 41 patients had a coronary event. In the overall population, clinical deterioration of anginal status (p<0.001, relative risk: 3.65) and fibrinogen (p<0.05, relative risk: 1.03) were independent predictors of spontaneous coronary events. Restenosis or new progression were not predictors. In asymptomatic patients (n=187), fibrinogen (p<0.01, relative risk=1.06) was the only predictor and restenosis was not an independent predictor of spontaneous coronary events. The best predictor of spontaneous coronary events at long-term follow-up after a first successful coronary angioplasty is clinical deterioration in anginal status in the months following the procedure. Restenosis does not appear as an independent predictor. Rapid progression observed in non-dilated sites is not an important prognostic factor.

Late regression of the dilated site after coronary angioplasty: a 5-year quantitative angiographic study

BACKGROUND

Limited data are available on the changes that occur at the dilated site late after coronary angioplasty. The aim of this study was to evaluate with quantitative angiography the natural history of changes that occur in the dilated segment between "early" (approximately 6 months) and "late" (approximately 5 years) follow-up after angioplasty.

METHODS AND RESULTS

Of 127 consecutive patients (174 lesions) with successful angioplasty, 125 underwent early angiography. Three patients subsequently died, and 24 underwent revascularization surgery or repeated angioplasty, giving a study-eligible population of 98 patients. Quantitative angiographic analysis was performed before and immediately after angioplasty and at early and late follow-up in the study population of 84 patients (115 lesions), which was 86% of study-eligible patients. Mean lesion diameter stenosis decreased from 36.3+/-14.2% at early to 29.6+/-13.5% at late follow-up (P<.0001). No lesion developed late restenosis by the 50% diameter loss criterion. Late regression was related to stenosis severity at early angiography (r=-.58, P<.001). Subgroups at early angiography of 40% to 49% stenosis and > or = 50% stenosis showed significant regression at late angiography.

CONCLUSIONS

Lesion regression at the dilated site is common late after angioplasty. The more severe a stenosis is at early angiography, the more likely the chance that there will be late regression. A strategy of watchful waiting may be appropriate for patients with restenotic lesions of borderline severity.

Long-term clinical follow-up after directional coronary atherectomy

Although several studies have been done to assess the safety, efficacy, and angiographic restenosis rates of directional coronary atherectomy (DCA), there have been no studies to document the need for repeat revascularization of the target vessel based purely on recurrence of symptoms. To answer this question, clinical and angiographic data were obtained for 187 consecutive patients undergoing this procedure on a native coronary artery utilizing a lesion specific approach in a referral hospital. Most of the patients had anginal symptoms that were not well controlled with medical therapy. The decision to perform DCA was based on the lesion characteristics (i.e., eccentric, ulcerated, or irregular discrete lesions in a large epicardial vessel). The procedure was successful in 96% of patients. In-hospital major complications were seen in 6 patients (3%) including acute myocardial infarction in 3 (1.5%) and emergency coronary artery bypass surgery in the other 3 (1.5%). There were no deaths. Among 141 consecutive successful patients on whom the procedure was performed between January 1992 and June 1994, 128 (91%) were contacted. At 6 months, revascularization was required in 20 patients for recurrent anginal symptoms, and there were no deaths or myocardial infarctions. The clinical restenosis rate, therefore, was 15.6%. At long-term follow-up (25 +/- 9 months), revascularization was performed in 3 more patients. One patient had a myocardial infarction and 3 patients died of noncardiac causes. Among those without clinical restenosis, 83% patients were asymptomatic and the rest had infrequent chest pains effectively managed with medications. The patients in the study group were using an average of 1.2 cardiac medications. Quality of life improved in 74% of the patients. Thus, in this study utilizing a lesion specific approach, the success rate for DCA was comparable to the published trials and in-hospital complications were few. The long-term clinical outcome was favorable with a low rate of clinical restenosis requiring repeat revascularization.

Angiographic predictors of neointimal thickening after successful coronary wall healing following percutaneous revascularization

This study was undertaken to characterize, by intracoronary ultrasound technique, the neointimal thickening at follow-up of treated coronary segments after successful arterial wall repair and to compare the findings with serial angiographic studies. We selected for study 81 patients with single-vessel coronary disease successfully treated by percutaneous revascularization who were angiographically and ultrasonically reevaluated at a mean follow-up time of 22 +/- 21 months; 23 had been treated by balloon angioplasty, 27 by directional atherectomy, and 31 by elective Palmaz-Schatz stent implantation. The late maximal neointimal thickness varied between 0.1 and 1.5 mm (mean 0.65 +/- 0.31 mm), and the neointimal area ranged between 0.97 and 14.9 mm2 (mean 5.19 +/- 3.14 mm2). The neointimal repair was thinner in patients who obtained a better acute angiographic result immediately after treatment and in stented (3.4 +/- 1.8 mm2) versus dilated (7.8 +/- 4.1 mm2) or resected (5 +/- 1.6 mm2, p < 0.001) segments. On the contrary, the repaired neointimal layer was thicker in those patients who angiographically exhibited less late luminal loss or even expansion and in those evaluated after a longer time since treatment. The acute gain and the time influence resulted in independent predictors of the degree of neointimal thickness. These findings suggest that two reparative mechanisms of the coronary wall may operate in close relation.