Restenosis following coronary angioplasty

Clinical characteristics and outcomes in patients with Takayasu arteritis coexisting with myocardial ischemia and neurological symptoms: A multicenter, long-term, follow-up study

Background

The incidence of coexisting myocardial ischemia and neurological symptoms in Takayasu arteritis (TA) is currently unknown. There is no standardized treatment algorithm in complex cases involving the coronary and intracranial arteries.

Objective

This study aimed to describe the clinical characteristics and outcomes in patients with TA coexisting with myocardial ischemia and neurological symptoms.

Methods

We retrospectively collected and assessed 1,580 patients with TA, and enrolled patients with myocardial ischemia and neurological symptoms from January 2002 to December 2021 in several hospitals. The incidence, clinical features, management strategy, and prognosis of these patients were evaluated.

Results

Ninety-four (5.9%, 94/1,580) patients with TA coexisting with myocardial ischemia and neurological symptoms were included in the present study. Imaging results showed that the subclavian arteries were the most frequently affected arteries and 37 patients had intracranial vascular abnormalities, comprising the basilar artery (6.1%, 17/279), middle cerebral artery (2.5%, 7/279), anterior cerebral artery (2.9%, 8/279), and posterior cerebral artery (1.9%, 5/279). Among patients with neurological symptoms, 25 patients underwent percutaneous transluminal angioplasty and 20 patients underwent stent implantation. The most common site of stenosis was the ostial and proximal segments of the coronary artery, with 142 lesions among 188 (75.5%) lesions. Thirty-eight patients adopted interventional therapy, 21 patients underwent surgical treatment, and the remaining 35 patients received conservative treatment. There were 20 (21.27%, 20/94) late deaths during a mean follow-up of 57.79 months. The mortality rate in the conservative treatment group was significantly higher than that in the interventional therapy and surgical treatment groups.

Conclusion

Patients with TA involving both the coronary and intracranial vessels are not rare. Stenosis and occlusion lesions most frequently involve the ostia and proximal segment of the arteries. Severe vascular lesions should be revascularized as soon as possible. These patients should be supplemented with glucocorticoids, antiplatelet, nitrates, and statins.

Coronary In-Stent Restenosis–Predictors and Treatment

BACKGROUND

Despite the use of modern drug-eluting stents (DES), in-stent restenosis (ISR) may still occur in as many as 2-10% of percutaneous coronary interventions (PCI) in certain lesion/patient subsets. ISR causes increased morbidity after stent implantation; acute myocardial infarction is a frequent correlate to a clinical ISR, arising in 5-10% of cases. Compared to de novo stenosis, patients with ISR also present more frequently with symptoms of unstable angina pectoris (45% versus 61%). In this article, we discuss the risk factors for ISR and the corresponding diagnostic measures and effective treatment strategies.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed, with special attention to current international guidelines and specialist society recommendations.

RESULTS

The type of implanted stent, the presence of diabetes mellitus, previous bypass surgery, and small vessel caliber are predictors for ISR. In their guidelines, the European specialist societies (ESC/EACTS) recommend repeated PCI with DES implantation or drug-coated balloon (DCB) angioplasty as the methods of choice for the treatment of ISR. This approach is supported by evidence from meta-analyses. The RIBS-IV trial showed that revascularization treatment of the target lesion is needed less often after everolimus-eluting stent (EES) implantation than after DCB dilatation (11 [7.1%] versus 24 [15.6%]; p = 0.015; hazard ratio: 0.43; 95% confidence interval: [0.21; 0.87]).

CONCLUSION

Because the pathogenesis of ISR is multifactorial, differentiated risk stratification is necessary. The identification of patient-, stent-, and lesion-related predictors is particularly important, as the most effective way to combat ISR is to prevent it.

The Potential of a Novel Class of EPAC-Selective Agonists to Combat Cardiovascular Inflammation

The cyclic 3′,5′-adenosine monophosphate (cAMP) sensor enzyme, EPAC1, is a candidate drug target in vascular endothelial cells (VECs) due to its ability to attenuate proinflammatory cytokine signalling normally associated with cardiovascular diseases (CVDs), including atherosclerosis. This is through the EPAC1-dependent induction of the suppressor of cytokine signalling gene, SOCS3, which targets inflammatory signalling proteins for ubiquitinylation and destruction by the proteosome. Given this important role for the EPAC1/SOCS3 signalling axis, we have used high throughput screening (HTS) to identify small molecule EPAC1 regulators and have recently isolated the first known non-cyclic nucleotide (NCN) EPAC1 agonist, I942. I942 therefore represents the first in class, isoform selective EPAC1 activator, with the potential to suppress pro-inflammatory cytokine signalling with a reduced risk of side effects associated with general cAMP-elevating agents that activate multiple response pathways. The development of augmented I942 analogues may therefore provide improved research tools to validate EPAC1 as a potential therapeutic target for the treatment of chronic inflammation associated with deadly CVDs.

Restenosis after Percutaneous Transluminal Coronary Angioplasty

Restenosis after percutaneous transluminal coronary angioplasty was demonstrated in 61 (29%) of 210 successfully treated patients. Mostly it occurred within 4 months after treatment and in arteries less than 3 mm in diameter. Careful clinical follow-up is therefore particularly important early after angioplasty of smaller arteries. Redilation can be performed without increased risk of restenosis.

Effects of probucol on restenosis after percutaneous coronary intervention: a systematic review and meta-analysis

BACKGROUND

Restenosis after percutaneous coronary intervention (PCI) is a remained clinical problem which limits long-term success of PCI. Although there was recognition that probucol in treating restenosis after percutaneous transluminal coronary angioplasty, the efficacy of probucol on restenosis after stent-implantation is controversial. So this meta-analysis was conducted to investigate the association between probucol and late restenosis.

METHODS

Articles were assessed by four trained investigators, with divergences resolved by consensus. PubMed, EMBASE, ScienceDirect and the Cochrane Central Register of clinical trials were searched for pertinent studies. Inclusion criteria were random allocated to treatment and a comparison of probucol-treated patients and control patients (not treated with lipid-lowering drug) undergoing PCI.

RESULTS

Fifteen studies with 859 subjects were analyzed. Major outcome, binary angiographic restenosis defined as >50% stenosis upon follow-up angiography, was significantly decreased with probucol treatment (RR = 0.59 [0.43, 0.80] among vessels, P = 0.0007; and RR = 0.52 [0.40, 0.68] among patients, P<0.00001). Probucol also increased the minimal luminal diameter (SMD = 0.45 [0.30, 0.61], P<0.00001) and decreased late loss upon follow-up after 6 months (SMD = -0.41 [-0.60, -0.22], P<0.0001). Moreover, there was a significantly lower incidence of major adverse cardiac events (MACE) in the probucol group than control group (RR = 0.69 [0.51, 0.93], P = 0.01).

CONCLUSION

Probucol is more than a lipid-lowering drug. It is also effective in reducing the risk of restenosis and incidence of MACE after PCI.

The future of EPAC-targeted therapies: agonism versus antagonism

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Although tractable to drug development, targeting of cAMP signalling has side effects.

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Selectively targeting EPAC1 and EPAC2 cAMP sensor enzymes may limit some of these off-target effects.

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EPAC agonists could be used to treat vascular inflammation (EPAC1) or type 2 diabetes (EPAC2).

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EPAC1 and EPAC2 antagonists could be used to treat heart disease.

Pharmaceutical manipulation of cAMP levels exerts beneficial effects through the regulation of the exchange protein activated by cAMP (EPAC) and protein kinase A (PKA) signalling routes. Recent attention has turned to the specific regulation of EPAC isoforms (EPAC1 and EPAC2) as a more targeted approach to cAMP-based therapies. For example, EPAC2-selective agonists could promote insulin secretion from pancreatic β cells, whereas EPAC1-selective agonists may be useful in the treatment of vascular inflammation. By contrast, EPAC1 and EPAC2 antagonists could both be useful in the treatment of heart failure. Here we discuss whether the best way forward is to design EPAC-selective agonists or antagonists and the current strategies being used to develop isoform-selective, small-molecule regulators of EPAC1 and EPAC2 activity.

Protective Effect of Policosanol on Endothelium and Intimal Thickness Induced by Forceps in Rabbits

Policosanol is a cholesterol-lowering drug isolated from sugar cane wax with concomitant antiplatelet effects that prevents lipofundin-induced atherosclerotic lesions in rabbits and rats, including foam cell formation, and also reduces foam cell formation in carrageenan-induced granulomas in rats, while it inhibits proliferation of smooth muscle cells induced in rabbit cuffed artery. This study was undertaken to determine whether policosanol prevents endothelium damage and increase in arterial wall thickness in rabbits with arterial walls damaged with a forceps. Artery forceps were placed over the central artery of the right ear of all rabbits, and each artery was injured eight times. Animals were randomly distributed into four groups: a positive control group treated with Tween 20/H2O vehicle, two groups treated with policosanol (5 and 25 mg/kg, respectively), and a group treated with aspirin (8 mg/kg). Treatments were given for 30 days. Damaged arteries were examined by light and electron (transmission and scanning) microscopy. To evaluate intimal thickening, areas of intima were measured, and a significant reduction in policosanol-treated animals was observed. The endothelial surface, studied with scanning electron microscopy, revealed several types of damage. In control group, the endothelial surface was severely damaged. De-endothelialized areas were reduced in policosanol-treated animals. Platelet adhesion to subendothelium was seen in all animals of the control group, whereas policosanol-treated groups exhibited significantly reduced platelet adhesion. Policosanol also reduced, dose-dependently, the platelet sequestration induced in the damaged vessel wall, partially preventing the reduction in platelet count. It is concluded that policosanol prevents endothelium injury and reduces significantly intimal thickness of rabbit arteries damaged with forceps.

Endovascular photodynamic therapy using mono-L-aspartyl-chlorin e6 to inhibit Intimal hyperplasia in balloon-injured rabbit arteries

BACKGROUND AND OBJECTIVE

Intimal hyperplasia (IH) leading to restenosis is a major complication of arterial revascularization. The purpose of this study was to investigate the effect of photodynamic therapy (PDT) using mono-L-aspartyl chlorin e6 (NPe6) as a photosensitizer and intraluminal radial irradiation for inhibition of IH experimentally.

STUDY DESIGN/MATERIALS AND METHODS

Study of laser transmission through the blood indicated that exclusion of blood is a prerequisite for intraluminal PDT. For homogeneous radial laser irradiation to the vessel wall, we used a newly developed cylindrical diffusing balloon laser fiber. Injuries were induced by pulling a balloon catheter through the right iliac artery of rabbits. One and 6 hours after the NPe6 injection (5mg/kg i.v.), drug distribution was examined by fluorescence microscopy. Nineteen rabbits received NPe6 at the time of injuries and PDT was performed with 664-nm laser at 30 and 10 J/cm(2) (20, 30, 40 mW/cm(2)) 1 hour after the injuries. The arteries were harvested at 2 days. In a second group of rabbits, PDT was given at 30 mW/cm(2) (30 J/cm(2)). Two weeks after treatment, the arteries were removed and examined histologically.

RESULTS

NPe6 was found to be distributed selectively in the injured media. Endovascular NPe6-PDT showed complete depletion of smooth muscle cells even with 10 J/cm(2) at 2 days. IH was significantly inhibited at 14 days after PDT.

CONCLUSIONS

Endovascular PDT of injured artery using NPe6 can prevent IH in this model of arterial wall injury and may become clinically useful for the prophylaxis of IH.

The effect of adjusting for baseline risk factors and post revascularisation coronary disease on comparisons between coronary angioplasty and bypass surgery

BACKGROUND

In CABRI at 1 year PTCA was associated with greater repeat revascularisation and angina (but not myocardial infarction or death). We determined whether adjusting for baseline risk factors and post revascularisation coronary disease offsets this disadvantage of PTCA.

METHODS

In the CABRI population the crude association of revascularisation mode (i.e. PTCA or CABG) with four clinical outcome (i.e. mortality, myocardial infarction, repeat revascularisation and angina) was adjusted for the baseline risk factors using a logistic regression model for each clinical outcome. A number of measures of angiographic coronary disease were used to assess post revascularisation coronary disease. One at a time, each of these measures was added to each of the four outcome models, to adjust for post revascularisation coronary disease.

RESULTS

Comparing adjusted and crude unadjusted association of PTCA with repeat revascularisation there was an increase from 12.8 (P<0.0005) (crude relative risk) to 16.7 (P<0.0005) (adjusted odds ratio), with angina, from 1.89 (P=0.001) to 1.98 (P<0.0019), and with mortality from 1.84 (P=0.092) to 2.15 (P=0.060). PTCA was not significantly associated with myocardial infarction, either crudely or after adjustment.

CONCLUSION

Adjusting for baseline risk factors and post revascularisation coronary disease tended to strengthen rather than weaken associations between PTCA and 1 year mortality, repeat revascularisation and angina at 1 year.

Endoluminal arterial injury in plasminogen-deficient mice

BACKGROUND

Vascular remodeling following arterial injury is characterized by an initial inflammatory reaction. Prior experiments using peritoneal inflammatory models have shown that the plasminogen system plays a role in the intensity of the inflammatory response. This study was undertaken to test the hypothesis that an absence of plasminogen would lead to a decrease in vascular remodeling.

METHODS

A left carotid artery injury was created with a flexible guidewire in both wild-type [Plg(+/+)] and plasminogen deficient [Plg(-/-)] mice. The right carotid artery was uninjured and used as a control. Three weeks postinjury, the mice were sacrificed and perfusion fixed, and the bilateral carotid arteries were sectioned for histological examination and collection of morphometric data.

RESULTS

After arterial injury, electron microscopy of the acutely injured artery revealed that the endothelium was denuded, that there were breaks in the internal elastic membrane, and that there was disruption of the medial layer of smooth muscle cells. The intimal and medial areas were significantly increased between the uninjured and injured carotid arteries of both Plg(+/+) (+80% intimal, +41% medial, P < 0. 05) and Plg(-/-) [+48% intimal, +24% medial, P < 0.05) mice. However, although there was a significant increase in the adventitial area of Plg(+/+) mice (+18%, P < 0.05), there was no difference in Plg(-/-) mice (-6%). Interestingly, even after 3 weeks, four of six injured arteries in Plg(-/-) mice had persistent thrombus within the medial layer, whereas this was not found in any of the nine Plg(+/+) mouse arteries.

DISCUSSION

Plasminogen deficiency inhibited the increase in adventitial area seen after injury in Plg(+/+) mice, but not the increase in intimal or medial areas. Not surprisingly, plasminogen-deficient mice also demonstrated a severe alteration in intramural thrombus clearance. Thus, specific aspects of the vascular remodeling response are dependent on plasminogen.

Role of restenosis in determining adverse outcome after coronary angioplasty vs bypass surgery

A group of patients who did not have restenosis after percutaneous transluminal coronary angioplasty (PTCA) was compared with a group receiving coronary artery bypass grafting (CABG). Restenosis only partially accounted for the greater morbidity after PTCA compared with CABG.

N-3 fatty acids do not prevent restenosis after coronary angioplasty: results from the CART study. Coronary Angioplasty Restenosis Trial

OBJECTIVES

The aim of the study was to investigate whether omega-3 fatty acids (n-3 FA) reduce the occurrence of restenosis after percutaneous transluminal coronary angioplasty.

BACKGROUND

Meta-analyses have shown significant reduction of restenosis after coronary angioplasty upon supplementation with n-3 FA.

METHODS

In a prospective, placebo-controlled, double-blind study, 500 patients were randomly allocated to treatment with n-3 FA (Omacor, Pronova AS, Oslo, Norway) 5.1 g/day or corn oil (placebo) starting at least two weeks prior to elective coronary angioplasty. The treatment was continued until restenosis evaluation by quantitative coronary angiography after six months. Stenosis was defined as a minimal luminal diameter (MLD) < 40% of the reference diameter. Successful coronary angioplasty was defined as > or = 20% acute gain in MLD and a residual stenosis < 50%. Restenosis was defined as > or = 20% late loss of diameter and stenosis > 50% or an increase in stenosis of > or = 0.7 mm. Three-hundred ninety-two patients fulfilled the criteria for initial stenosis and successful coronary angioplasty, and, except four patients who died, none were lost for follow-up.

RESULTS

Restenosis occurred in 108/266 (40.6%) of the treated stenoses in the Omacor group and in 93/263 (35.4%) in the placebo group (odds ratio [OR] 1.25, 95% confidence interval [CI] [0.87-1.80] p = 0.21). In the Omacor group one or more restenoses occurred in 90/196 (45.9%) patients as compared with 86/192 (44.8%) in the placebo group (OR 1.05, 95% CI [0.69-1.59] p = 0.82).

CONCLUSIONS

Supplementation with 5.1 g n-3 FA/day for six months, initiated at least two weeks prior to coronary angioplasty did not reduce the incidence of restenosis.

Impact of postangioplasty restenosis on comparisons of outcome between angioplasty and bypass grafting. Coronary Angioplasty versus Bypass Revascularisation Investigation (CABRI) Investigators

Restenosis is a major limitation of percutaneous transluminal coronary angioplasty (PTCA). In this study, we assessed the impact of restenosis on PTCA with reference to coronary angioplasty bypass grafting (CABG). In the Coronary Angioplasty versus Bypass Revascularisation Investigation (CABRI) PTCA population, those who had restenosis were defined as those needing a second revascularization at a site revascularized at the initial procedure. The 1-year clinical outcome of the nonrestenotic group (n=437) was compared with those who underwent CABG (n=453). There was no difference in deaths. In the nonrestenotic PTCA group, the incidence of more infarctions was insignificant (relative risk [RR] 1.9, 95% confidence intervals [CI] 0.96 to 3.75, p=0.064), there was a much greater need for repeat revascularization (RR 8.6, CI 5.14 to 14.41, p <0.0005), and patients had a poorer angina status (RR 1.46, CI 1.01 to 2.13, p=0.046). Using 2 measures of coronary disease, the degree of pre- and postrevascularization disease was compared between groups. There were no differences in prerevascularization disease. However, using either measure, residual postrevascularization disease was more frequent in the nonrestenotic PTCA group. Restenosis only partially accounts for the greater morbidity seen after PTCA, compared with CABG, in multivessel disease. The greater likelihood of residual disease post-PTCA may contribute to this greater morbidity.

Differential restenosis rate of individual coronary artery sites after multivessel angioplasty: implications for revascularization strategy. CABRI Investigators. Coronary Angioplasty versus Bypass Revascularisation Investigation

BACKGROUND

Restenosis is a major limitation of angioplasty. In this analysis we assessed the effects of lesion site and quality of dilatation on restenosis rate in the Coronary Angioplasty versus Bypass Revascularization Investigation population who underwent angioplasty.

METHODS

The angiographic quality of the successful angioplasty revascularization at each site was assessed, and the subsequent restenosis rate was determined. Restenosis was defined by the need for a second angioplasty at the initial site or by surgical coronary bypass grafting at or distal to the initial site.

RESULTS

The restenosis rate was unaffected by quality of dilatation but was significantly more common in the proximal left anterior descending artery compared with other sites, whether or not optimal dilatation had been achieved (relative risk 2.0 and 1.9, respectively).

CONCLUSION

Revascularization strategies in multivessel disease should consider the presence or absence of a proximal left anterior descending artery target. Furthermore in studies in which restenosis is an outcome of interest, an allowance should be made for the distribution of target disease.

Thrombospondin-1 is elevated with both intimal hyperplasia and hypercholesterolemia

BACKGROUND

Thrombospondin-1 (TSP-1) is important in platelet adhesion and aggregation, inflammation, cell to cell interaction, angiogenesis, and smooth muscle cell (SMC) proliferation. TSP-1 expression increases rapidly with injury. Therefore, we hypothesize that TSP-1 may play a role in the development of intimal hyperplasia (IH). The purpose of this study is to examine the interaction between cholesterol and TSP-1 on SMC proliferation and to quantitatively assess TSP-1 expression in an established model of IH, with and without underlying cholesterol-induced atherosclerosis.

MATERIALS AND METHODS

In vitro, rabbit aortic SMC culture studies were performed to see the effect of TSP-1 antibodies on PDGF and, separately, cholesterol-induced SMC proliferation. In vivo, 23 rabbits were fed either a regular or a high-cholesterol diet. Hypercholesterolemia was confirmed by measurement of serum levels. Subsets underwent intraluminal aortic injury. Aortas were harvested 8-10 weeks later. Arterial wall TSP-1 was evaluated immunohistochemically and quantified by computer image analysis.

RESULTS

In vitro, TSP-1 antibodies were able to inhibit PDGF and cholesterol-induced SMC proliferation (P < 0.05). In vivo, TSP-1 was found predominantly in the extracellular matrix in the rabbit aorta. IH was uniformly seen status-post angioplasty. Hyperplasia was more prominent in samples from hypercholesterolemic animals. ANOVA and Student's t test analyses demonstrated significantly more TSP-1 in the high-cholesterol/angioplasty group than in all other groups (P = 0.0006 vs regular diet/no angioplasty group).

CONCLUSIONS

These data are consistent with the hypothesis that TSP-1 contributes to the development of IH. This study suggests that injured arteries in hypercholesterolemic atherosclerotic rabbits overexpress TSP-1.

Limitations of angiotensin-converting enzyme inhibitor in restenosis of a deep arterial injury model

Cilazapril (CLZ) has been reported to reduce intimal hyperplasia in a rat carotid model of restenosis. The purpose of this study was to determine whether CLZ inhibits restenosis after deep arterial injury in lathyritic rats. The lathyritic rat was used as a model of deep arterial injury; in this model the internal elastic lamina is easily broken by balloon injury because of the fragility of the connective tissue. Deep arterial injury is defined as rupture of the internal elastic lamina with damage to both the intima and the media. The rats were divided into 4 groups (n = 40): mild injury (intimal damage with intact internal elastic lamina), mild injury +CLZ, deep injury, and deep injury +CLZ. In the CLZ-treated groups, the drug was administered orally (10 mg/day) from 7 days before balloon injury until the time of sacrifice 21 days after balloon injury. The intimal hyperplasia was determined histologically using a computerized morphometry program. At sacrifice, blood pressure was lower in the CLZ-treated groups than in the untreated (control) rats (p < 0.05). In the mild injury model, CLZ decreased intimal hyperplasia markedly. In contrast, CLZ failed to reduce intimal hyperplasia in the rats with deep injury. CLZ markedly decreased neointimal hyperplasia in mild injury. In contrast, CLZ failed to reduce intimal area in deep injury. The type of arterial injury seems to determine the effectiveness of CLZ.

Preliminary results achieved by a computer-assisted system for controlled balloon dilatation of coronary and peripheral arteries

In percutaneous balloon angioplasty the extent of trauma to the vessel as determined by slope of balloon inflation, peak pressure, and inflation time is crucial to the success of the intervention. These parameters are still not standardized and hence open to the operator. To elucidate this problem, a computer-assisted PTCA system (CAPS) was developed. CAPS is composed of a motor driven unit, a central processing and power unit, and a notebook. A syringe is clamped onto the motor unit and connected to a pressure gauge. CAPS may be linked to all types of balloon catheters. The notebook allows for preselection of peak pressure, slope of pressure increase, and inflation time. During balloon inflation, adjustments are made in a closed-loop system. On a screen, the inflation process is supervised in digital numbers and analogous curves. After the procedure, patient data and inflation curves may be recalled for analysis. In conclusion, CAPS by controlled inflation theoretically may reduce the mechanical trauma to the arteries. Further refinements should aim at gaining information on the lesions' characteristics and on the dilatation process itself.

Multiple stent implantation in single coronary arteries: acute results and six-month angiographic follow-up

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

High and constant plasma levels of tissue plasminogen activator and PEG-hirudin can be achieved by subcutaneous delivery

Intramural thrombosis is a consistent finding in the arteries of patients who die following coronary angioplasty. This thrombosis is thought to have a role in restenosis, which is a common complication of coronary angioplasty. It has been hypothesised that antithrombotics such as hirudin or tissue-type plasminogen activator (tPA), may be therapeutically useful following angioplasty. This report describes the bioavailability of both agents following subcutaneous (sc) injection in cholesterol-fed rabbits. Intravenously delivered tPA has a half-life of 3-5 minutes. The half-life of intravenously administered hirudin is less than one hour in many species. In order to prolong the duration of action recombinant hirudin was conjugated to polyethylene glycol (PEG). Polyethylene glycol conjugated recombinant hirudin (PEG-rH) (0.7 mg/kg) antigen and activity were measurable after just 1 hr, reaching a maximum (663 and 884 ng/ml respectively) at 12 hours. Significant levels were present in rabbit plasma 24 hours after injection. Subcutaneously delivered recombinant (r-tPA) (1 mg/kg) was present in significant amounts 1 hr after injection, reaching a maximum (92 IU/ml) at 2 hours. Levels of tPA at 9 hours were approximately 80x normal circulating levels. High and constant levels of functional activity of both PEG-rH and r-tPA in rabbit plasma are achieved by subcutaneous delivery.

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

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

Inhibition of fibro-intimal hyperplasia in a polytetrafluoroethylene vascular graft with standard heparin and low molecular weight heparin

BACKGROUND

Fibro-intimal hyperplasia is a significant cause of late prosthetic vascular graft failure. The influence of standard unfractionated sodium heparin (SH) and low molecular weight heparin (LMWH) on intimal hyperplasia was studied in a sheep polytetrafluoroethylene (PTFE) end-to-side carotid artery vascular graft model.

METHODS

Sodium heparin was administered subcutaneously in a dose of 7250 units twice daily (n = 6). Enoxaparin, an LMWH, was administered subcutaneously in two different dose regimens of 2 mg/kg (n = 6) and 5 mg/kg (n = 6) daily. At 1 month the animals were killed and the grafts sectioned. An intima to media ratio was obtained under light microscopy, using an eyepiece graticule, from measurements taken from the floor of the native artery. Results were analysed with a rank-sum correlation test.

RESULTS

Control sheep had a median ratio of 0.104, an SH level of 0.021, a low-dose LMWH level of 0.035 and a high-dose LMWH level of 0.017. There was a significant difference between control and SH (P < 0.001), control and high-dose LMWH (P < 0.05), and SH and low-dose LMWH (P < 0.05), but there were no differences between SH and high-dose LMWH or between the two LMWH groups. Both LMWH groups recorded high anti-Xa levels but only slight prolongation of thrombin time.

CONCLUSIONS

Low molecular weight heparin has a similar effect to SH on the inhibition of fibro-intimal hyperplasia in this animal model but is safer, with less bleeding potential, and is more convenient to administer as a once-daily dose.

Preventive effects of probucol on restenosis after percutaneous transluminal coronary angioplasty

This protocol was performed to elucidate the preventive effects of probucol on restenosis after percutaneous transluminal coronary angioplasty (PTCA). A total of 118 patients with 134 vessels undergoing successful PTCA was randomly and prospectively assigned to the probucol group (group P) or the control group (group C). The subjects consisted of 91 men and 27 women, with a mean age of 63.4 +/- 2.3 years. Sixty-six vessels of 59 patients in group P and 68 vessels of 59 patients in group C were evaluated by coronary angiography at 3 months after PTCA. Probucol (0.5 mg/day) was administered between >7 days before PTCA and 3 months after PTCA. The serum total cholesterol (TC) level and the formula low-density lipoprotein cholesterol (formula LDL-C) in group P decreased from 203.8 +/- 43.1 to 169.6 +/- 39.4 mg/dl and from 131.4 +/- 0.7 to 108.7 +/- 2.5 mg/dl, whereas in group C, the levels decreased only from 202.3 +/- 32.1 to 194.2 +/- 29.8 mg/dl and from 129.2 +/- 38.1 to 124.3 +/- 31.7 mg/dl, respectively. The restenosis rate was significantly lower in group P (19.7%; 13 of 66 vessels) than in group C (39.7%; 27 of 68 vessels; p < 0.05). In group P, the probucol blood concentration was significantly higher in the subjects without restenosis (31 +/- 9 microg/ml) than in those with restenosis (18 +/- 8 microg/ml; p < 0.01), but the serum TC and formula LDL-C levels were not significantly different between these two groups. In summary, long-term administration of probucol significantly reduces the incidence of restenosis after PTCA. it was suggested that the mechanism of this preventive effect was not reducing the serum TC or formula LDL-C levels, but rather an inhibitory action on smooth muscle cell proliferation.

Impaired fibrinolysis early after percutaneous transluminal coronary angioplasty is associated with restenosis

This study examined the role of fibrinolytic components in the process of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Seventy-two patients with single-vessel disease who underwent successful PTCA were prospectively selected. Tissue plasminogen activator (TPA), free plasminogen activator inhibitor-1 (free PAI-1), TPA/PAI-1 complex, and total PAI-1 antigen levels were measured before, at 1 week after, and at 3 months after PTCA. Six months after PTCA, the study patients were divided into two groups: 41 patients without restenosis and 31 patients with restenosis. There were no significant differences with regard to sex, age, coronary risk factors, or morphologic changes in the target lesions between the two groups. There were no significant differences in plasma TPA, TPA/PAI-1 complex, or total PAI-1 levels at each sampling period, or in the time courses between the two groups, except for total PAI-1 levels at 1 week after PTCA. Although no significant differences in free PAI-1 levels before PTCA were observed, free PAI-1 levels after PTCA in the patients with restenosis were significantly higher than those in the patients without restenosis. In addition, each group had a significant change in the time course of free PAI-1 levels. The results suggest that impaired fibrinolysis early after PTCA might affect the repair process of vascular injury, which leads to restenosis, and also that serial determination of free PAI-1 levels could help predict restenosis.

Prevention of restenosis after coronary angioplasty with low-density lipoprotein apheresis

A prospective study was performed to determine whether low-density lipoprotein (LDL) apheresis, when performed only immediately before and after percutaneous transluminal coronary angioplasty (PTCA), is effective in preventing restenosis of coronary artery lesions following PTCA. Thirty-six patients with coronary heart disease (CHD) and hypercholesterolemia were divided into 2 groups. The 9 patients in the LDL group underwent LDL-apheresis 1 day before and 5 days after PTCA while the 27 patients of the control group underwent PTCA but did not undergo LDL-apheresis. Follow-up coronary angiography (CAG) was performed 4 months after PTCA. The rate of restenosis of coronary artery lesions was significantly lower in the LDL group (0%) than in the control group (30%). These findings suggest that LDL-apheresis, when performed before and after PTCA, is effective in preventing restenosis of coronary artery lesions in patients with CHD and hypercholesterolemia.

Seeding with omental cells prevents late neointimal hyperplasia in small-diameter Dacron grafts

BACKGROUND

The influence of complete endothelialization of a prosthetic graft on development of late neointimal hyperplasia is unknown. This study was designed to investigate the effect of complete coverage with endothelial-like cells on late neointimal hyperplasia in small-diameter Dacron grafts seeded with omental cells in a canine model.

METHODS AND RESULTS

Four-mm-ID Dacron grafts were seeded with cells from omentum and implanted in the carotid arteries in 24 mongrel dogs. Each dog received one seeded and one nonseeded graft. The graft patencies were assessed by angiography at 1, 5, 12, 26, and 52 weeks after surgery. The prostheses were explanted at 5, 12, 26, and 52 weeks after surgery and underwent microscopic studies. The actuarial patency rates at 1, 5, 12, 26, and 52 weeks were 100%, 95%, 95%, 95% and 95% for seeded grafts and 100%, 86%, 49%, 40%, and 13% for nonseeded grafts, respectively. The seeded grafts exhibited a uniform endothelial-like luminal monolayer without the development of late neointimal proliferation or anastomotic neointimal hyperplasia. Neointimal tissue thickness increased up to 6 months; no additional progression of the subendothelial tissue thickness was observed, in fact there was an insignificant decrease.

CONCLUSIONS

Seeding with omental cells prevents development of late neointimal hyperplasia of small diameter prosthetic vascular grafts in a canine model.

Failure of heparin to inhibit intimal hyperplasia in injured baboon arteries. The role of heparin-sensitive and -insensitive pathways in the stimulation of smooth muscle cell migration and proliferation

BACKGROUND

Heparin is a potent inhibitor of smooth muscle cell (SMC) growth and intimal hyperplasia in animal models but has been ineffective in inhibiting restenosis in humans. This difference may relate to flaws in clinical study design or, alternatively, to interspecies differences in SMC response to heparin. To determine whether heparin could inhibit intimal hyperplasia in a species more closely related to humans, we studied the effect of a low-molecular-weight heparin (LMWH) on baboon SMC proliferation and migration in culture and in arteries subjected to experimental angioplasty.

METHODS AND RESULTS

LMWH or saline was infused continuously after experimental angioplasty of baboon peripheral arteries (six animals per group). After 28 days, bromodeoxyuridine (BrdU) was given to label proliferating cells, and balloon-injured arteries were perfusion-fixed in situ and removed for analysis. All arteries had reendothelialized (Evans blue dye exclusion). LMWH increased partial thromboplastin time (LMWH, 81.7 +/- 8.4 seconds versus saline, 34.7 +/- 0.8 seconds [mean +/- SEM]; P = .004) but failed to inhibit intimal thickening or SMC proliferation (intimal area: LMWH, 0.19 +/- 0.03 mm2 versus saline, 0.21 +/- 0.03 mm2; BrdU labeling: LMWH, 2.9 +/- 0.6% versus saline, 2.4 +/- 0.4%; P = NS). In culture, LMWH and standard heparin (100 micrograms/mL) significantly inhibited serum-induced but not platelet-derived growth factor (PDGF-BB)-induced SMC proliferation (% control, serum: LMWH, 60.5 +/- 4.0%, P = .0002; standard heparin, 29.4 +/- 8.2%, P = .0001; % control, PDGF-BB: LMWH, 117.7 +/- 11.3%, P = NS; standard heparin, 90.9 +/- 14.4%, P = NS) and SMC migration (% control, serum: LMWH, 15.3 +/- 1.9%, P = .0198; standard heparin, 26.4 +/- 13.8%, P = .0032; % control, PDGF-BB: LMWH, 98.5 +/- 14.3%, P = NS; standard heparin, 100.0 +/- 13.5%, P = NS).

CONCLUSIONS

LMWH failed to inhibit intimal hyperplasia in a baboon angioplasty model. Furthermore, LMWH blocked serum-induced but not PDGF-BB-induced SMC proliferation and migration in culture. Thus, heparin-sensitive and -insensitive pathways exist for SMC activation. The relative importance of each pathway induced by injury may vary between species and thus account for different responses to heparin.

Comparison of effects of high-dose and low-dose aspirin on restenosis after femoropopliteal percutaneous transluminal angioplasty

BACKGROUND

Long-term treatment with aspirin is recommended in patients with large-vessel peripheral arterial disease since these patients have a high risk of death from cardiovascular causes. Recent studies have demonstrated the prophylactic effect of low-dose aspirin in reducing the risk of cardiovascular events. Since aspirin is also recommended for prevention of late recurrence after peripheral angioplasty, the present study was undertaken to compare the effects of high-dose (1000 mg/d) and low-dose (100 mg/d) aspirin on long-term patency after femoropopliteal angioplasty.

METHODS AND RESULTS

Two hundred sixteen patients treated successfully by percutaneous transluminal angioplasty for femoropopliteal lesions were randomly allocated to therapy with either 1000 or 100 mg aspirin daily. The follow-up was 24 months. The long-term results were analyzed using the Kaplan-Meier method, and differences between curves of cumulative patency were determined with the Wilcoxon and log-rank statistics. Complete follow-up information (patency after 24 months, restenosis, and death) was obtained in 207 patients. During the 2-year follow-up period, 72 patients--36 in the high-dose and 36 in the low-dose aspirin group, respectively--developed angiographically verified reobstruction within the recanalized segment. By intention-to-treat analysis, the cumulative patency rates at 24 months were 62.5% in the high-dose and 62.6% in the low-dose aspirin group (Wilcoxon, P = .97; log-rank, P = .97). The cumulative survival at 24 months of follow-up was 86.6% in the high-dose and 87.7% in the low-dose aspirin group. The number of patients discontinuing therapy was 30 in the high-dose and 11 in the low-dose aspirin group (P < .01). Fewer patients receiving 100 mg of aspirin discontinued therapy because of gastrointestinal symptoms (4 versus 20).

CONCLUSIONS

The data indicate that 100 mg aspirin is no less effective in the prevention of restenosis after femoropopliteal PTA than a 1000-mg dose and has fewer side effects.

c-myc in vasculoproliferative disease

Antisense oligonucleotides to genes central to cellular proliferation have suppressed smooth muscle cell growth in vitro and in vivo. We now report that although the response of cultured smooth muscle cells to antisense oligonucleotides to c-myc and c-myb is identical, the response of the injured arterial wall to these oligomers depends on the kinetics of gene expression and oligonucleotide delivery. Two different antisense oligonucleotides to each oncogene were administered to the perivascular aspect of injured rat carotid arteries via polymer-based delivery systems. The acute release of antisense oligonucleotides from the Pluronic gels reduced in vitro cell growth 54.8% with c-myc and 56.9% with c-myb. The more sustained release from ethylene vinyl acetate copolymer (EVAc) matrices was slightly less efficient, inhibiting proliferation 47.3% and 43.3%, respectively. However, although both EVAc and Pluronic release of c-myb antisense oligonucleotide sequences inhibited intimal hyperplasia 2 weeks after injury, only the more prolonged EVAc matrix release of antisense oligonucleotide to c-myc was effective. The failure of the short course of c-myc oligomer release from Pluronic gels stemmed from early successful suppression with late loss of regulation and not from inactivation of the antisense oligonucleotide within the polymeric gel. Within 24 hours of injury, Pluronic-based release of c-myc antisense oligomers reduced mRNA levels in the tunica media 2.5-fold and immunocytochemical identification of c-myc expression by 98.8%. As a result, the number of proliferating cells was decreased 6.5-fold 3 days after injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of angiographic and hemodynamic results of coronary balloon angioplasty on late angiographic outcome

A small residual stenosis and a low residual translesional pressure gradient after percutaneous transluminal coronary angioplasty (PTCA) are thought to be associated with lower rates of restenosis. However, these two posprocedure parameters have not been studied simultaneously in relation to late angiographic outcome. Restudy angiograms after successful single-vessel and single-lesion PTCA were performed in 1261 patients, who were divided into three groups according to final residual stenosis: group 1, 0% to 19%, group 2, 20% to 34%, and group 3, 35% to 49%. This study population also was divided into two groups by final residual pressure gradient: < or = 17 and > or = 18 mm Hg. Luminal patency at restudy and restenosis rates by these definitions were studied. By the definition of > or = 50% stenosis at restudy, group 1 had the lowest restenosis rate, and group 3 had the highest. By the definition of an increase of > or = 30% stenosis compared with the immediate post-PTCA result, group 1 had the highest restenosis rate, and group 3 had the lowest. Although it had the greatest loss of luminal diameter over the follow-up period, group 1 maintained the greatest luminal patency at restudy. A residual pressure gradient < or = 17 mm Hg was associated with lower restenosis rate regardless of the definition used. Despite greater loss of luminal diameter over the follow-up period, optimal postprocedure angiographic results may result in better long-term luminal patency. Transluminal pressure gradient is more predictive of late angiographic results regardless of the definition used. Further studies, with hemodynamic measurements, may reveal potential clinical implications.

Contrasting effects of the intermittent and continuous administration of heparin in experimental restenosis

BACKGROUND

Heparin inhibits proliferation of smooth muscle cells in culture and intimal hyperplasia in experimental animals but paradoxically exacerbates vascular injury in clinical trials. To determine whether the difference in the means by which heparin was administered explained the benefit in animals and aggravation in humans, we examined the vascular effects of a range of heparin treatments.

METHODS AND RESULTS

When laboratory rats were injected subcutaneously with heparin (55.5 IU, approximately 1.0 mg/kg) per clinical trial protocols, intimal hyperplasia after arterial injury was exacerbated rather than alleviated. The intima to media area ratio was increased 22.5% with every-other-day injections and was increased 16.8% with daily injections. When the daily dose of heparin was increased to 7.2 mg/kg or when injections were initiated a week before injury, intimal hyperplasia was made even worse (52.2% and 59.9% above control). Twice-daily heparin, 7 and 17 hours apart, had no demonstrable effect one way or the other, and it was not until the heparin was administered at 12-hour intervals that intimal hyperplasia and cell proliferation were lessened (44.6% decrease). The greatest reduction in intimal hyperplasia was obtained when the heparin was administered continuously. The continuous osmotic pump intravenous infusion of heparin inhibited 62.5% of the expected proliferation, and perivascular polymeric device release of heparin blocked the response by 74.2%. While subcutaneous injections transiently increased activated partial thromboplastin time, neither mode of continuous delivery altered coagulation.

CONCLUSIONS

We might reconsider the use of heparin in vascular diseases and not neglect this promising compound because of inappropriate extrapolation from the laboratory to clinical use.

Effects of LDL apheresis on restenosis after angioplasty

We performed long-term maintenance LDL apheresis therapy on patients with hypercholesterolemia after undergoing PTCA, and investigated the therapeutic effects of reducing serum cholesterol, LDL-cholesterol and Lp(a). LDL apheresis significantly reduced serum lipids and was an efficacious therapy in the prevention of recurrent stenosis after PTCA.

Evaluation of ketanserin in the prevention of restenosis after percutaneous transluminal coronary angioplasty. A multicenter randomized double-blind placebo-controlled trial

BACKGROUND

Ketanserin is a serotonin S2-receptor antagonist that inhibits the platelet activation and vasoconstriction induced by serotonin and also inhibits the mitogenic effect of serotonin on vascular smooth muscle cells.

METHODS AND RESULTS

We conducted a randomized, double blind, placebo-controlled trial to assess the effect of ketanserin in restenosis prevention after percutaneous transluminal coronary angioplasty (PTCA). Patients received either ketanserin (loading dose, 40 mg 1 hour before PTCA; maintenance dose, 40 mg bid for 6 months) or matched placebo. In addition, all patients received aspirin for 6 months. Coronary angiograms before PTCA, after PTCA, and at 6 months were quantitatively analyzed. Six hundred fifty-eight patients were entered into the intention-to-treat analysis. The primary clinical end point of the study was the occurrence between PTCA and 6 months of any one of the following: cardiac death, myocardial infarction, the need for repeat angioplasty, or bypass surgery. It also included the need for revascularization actuated by findings at 6-month follow-up angiography. The primary clinical end point was reached by 92 (28%) patients in the ketanserin group and 104 (32%) in the placebo group (RR, 0.89; 95% CI, 0.70, 1.13; P = .38). Quantitative angiography after PTCA and at follow-up was available in 592 patients (ketanserin, 287; control, 305). The mean difference in minimal lumen diameter between post-PTCA and follow-up angiogram (primary angiographic end point) was 0.27 +/- 0.49 mm in the ketanserin group and 0.24 +/- 0.52 mm in the control group (difference, 0.03 mm; 95% CI, -0.05, 0.11; P = .50).

CONCLUSIONS

Ketanserin at the dose administered in this trial failed to reduce the loss in minimal lumen diameter during follow-up after PTCA and did not significantly improve the clinical outcome.

High frequency rotational ablation: an alternative in treating coronary artery stenoses and occlusions

OBJECTIVE

To prove the safety and effectiveness of high frequency rotational ablation of coronary artery stenoses and occlusion in humans.

SUBJECTS

106 patients with symptoms (91 men, 15 women) who had 67 significant stenoses, mainly types B and C, and 46-chronic occlusions.

MAIN OUTCOME MEASURES

Mean change in diameter stenosis after rotational angioplasty alone and in combination with percutaneous transluminal coronary angioplasty immediately after treatment and 24 hours and six months later; restenosis rates at six months; complication of treatment.

RESULTS

Rotational ablation could not be used in five stenoses and 16 chronic occlusions because of inability to reach or cross the lesion with the Rotablator guide wire. In four cases rotational ablation failed. Initial angiographic and clinical success by rotational ablation was achieved in 40 of the 67 stenoses (60%) and in 18 of the 46 chronic occlusions (39%). Additional balloon angioplasty was performed in 45 patients, increasing the success rates to 79% and 54%, respectively. In the 62 stenoses treated by rotational ablation the angiographic diameter stenoses were reduced from 76% (SD 14%) to 32% (14%) after Rotablator treatment alone and from 75% (11%) to 33% (17%) with additional balloon angioplasty. In the 30 chronic occlusions treated by rotational ablation the angiographic diameter stenoses were reduced to 38% (18%). At six months angiographic restenosis was evident in nine of the 25 (36%) stenoses treated with rotational ablation alone, in seven of the 22 (32%) stenoses treated with rotational and balloon angioplasty, and in 14 of the 24 (58%) chronic occlusions. There were no procedural deaths and two patients (2%) underwent emergency coronary artery bypass grafting. Although no transmural infarction occurred, there were five (6%) non-Q wave infarctions (two embolic side branch occlusions, two subacute occlusions, and one acute occlusion). Clinically insignificant slight increases in creatine kinase activity were seen in five patients (6%). Severe coronary artery spasm unresponsive to medical treatment was provoked in seven cases (8%).

CONCLUSIONS

High frequency rotational ablation is a safe and effective method for treating type B and C coronary artery lesions with results comparable to percutaneous transluminal coronary balloon angioplasty. The combined use of rotational ablation and balloon angioplasty is feasible and is necessary in about half of all procedures, in most cases because the lumen created by the biggest burr is too small.

Both increased and decreased platelet adhesion to thermally injured subendothelium is caused by denaturation of von Willebrand factor

BACKGROUND

Thermal angioplasty methods heat the arterial wall. We related platelet adhesion to the temperature to which subendothelium and purified adhesive proteins had been exposed.

METHODS AND RESULTS

Cultured subendothelium, purified von Willebrand factor, collagen types I and III, or fibronectin was applied to glass coverslips. Coverslips were mounted on a heating device that applied a temperature gradient from 30 to 100 degrees C. De-endothelialized umbilical arteries were heated by immersion in phosphate-buffered saline. After cooling to room temperature, the surfaces were perfused with blood at 37 degrees C (shear rate, 1600 sec-1). Compared with 37 degrees C, platelet adhesion to endothelial cell matrix was significantly reduced by 25%, 50% or 75% after heating to 69 +/- 1 degree C (mean +/- SEM, P < .05), 72 +/- 1 degree C, or 75 +/- 1 degree C, respectively. Platelet coverage to umbilical artery subendothelium was in the same way significantly reduced after heating to 71 +/- 1 degree C, or 77 +/- 1 degree C, respectively. In contrast to endothelial cell matrix, however, heating to about 55 degrees C increased platelet coverage from 30 +/- 5% to 54 +/- 6% (P < .05). Both platelet adhesion to von Willebrand factor and monoclonal antibody binding against the GpIb binding site of von Willebrand factor showed a comparable temperature dependence as platelet adhesion to subendothelium, provided the proper von Willebrand factor concentration was used. Platelet adhesion to heated collagen types I and III was increased and maximal at 57 +/- 2 degrees C and 62 +/- 2 degrees C, respectively. Preincubation of collagen III with proteins resulted in decreased platelet adhesion with increasing temperatures. Heating did not affect the reactivity of fibronectin.

CONCLUSIONS

In vitro platelet adhesion to human subendothelium is reduced by more than 50% after heating it briefly to more than 74 degrees C. Temperatures in excess of 80 degrees C reduce platelet adhesion by at least 85%. Thermal denaturation of von Willebrand factor is responsible not only for the decreased thrombogenicity above 71 degrees C but also for the increased thrombogenicity near 55 degrees C, provided that the von Willebrand factor concentration is low.

Restenosis after coronary angioplasty

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

Restenosis after coronary angioplasty

Coronary angioplasty is used to treat coronary atherosclerotic disease in many patients. One problem with coronary angioplasty is the phenomenon of restenosis. Restenosis appears to be a universal response to arterial wall injury. The biological events that underlie restenosis are characterized by: platelet adhesion and aggregation at sites of damaged endothelium, and within dissections into the medial layers, release of platelet derived growth-promoting substances, inflammation of the injured medial zone, transformation, migration, and proliferation of smooth muscle cells of the media following their activation by growth-promoting substances, secretion of copious amounts of extracellular matrix material, and finally, termination of the growth process following regrowth of endothelium over the damaged area. More than a decade of research work has helped identify clinical correlates of restenosis after coronary angioplasty. Patient-related correlates include male gender, unstable angina, diabetes, and continued smoking after angioplasty. Lesion-related correlates include multilesion and multivessel procedures, higher post-angioplasty residual stenosis, proximal vessel location, location in the left anterior descending coronary artery, location in a vein graft, long lesions, and total occlusions. However, for the purposes of individual patient care, clinical correlates are not particularly helpful. No group of variables has predicted complete freedom from restenosis, and conversely no group of variables has reliably indicated its presence. All patients undergoing angioplasty will require some form of follow-up evaluation. Symptom status by itself has not been found to be useful for predicting restenosis. However, when symptom status is combined with exercise thallium-201 scintigraphy, performed 4-6 months after angioplasty, it is less than ideal, but has a negative predictive value of over 90%. This means that over 90% of patients who are asymptomatic and have no evidence of ischemia by thallium-201 scintigraphy, will not have angiographic restenosis. Numerous clinical trials have been performed in order to reduce or prevent restenosis. Almost all have been disappointing, while a few have been encouraging. Studies of antiplatelet agents such as aspirin, dipyridamole (Boehringer Ingelheim Pharmaceuticals Inc., Ridgefield, CT, USA), and Ticlopidine (Syntex, Humgcao, Puerto Rico) have not shown efficacy, yet studies of an inhibitor of platelet-derived growth factor have been provocatively encouraging. No reduction in restenosis rates was found with the anticoagulants Coumadin (Du Pont Pharmaceuticals, Wilmington, DE, USA) and Heparin (Wyeth-Ayerst, Philadelphia, PA, USA). Fish oils (omega fatty acids) have been found in several clinical trials to provide modest, but encouraging, reductions in restenosis, but await further confirmation.(ABSTRACT TRUNCATED AT 400 WORDS)

Relation between activated smooth-muscle cells in coronary-artery lesions and restenosis after atherectomy

BACKGROUND

Neointimal proliferation leading to restenosis frequently develops after coronary angioplasty. This process is associated with a change in vascular smooth-muscle cells from a contractile (quiescent) phenotype to a synthetic or proliferating (activated) one. We investigated whether the presence of activated smooth-muscle cells in coronary lesions at the time of coronary atherectomy predisposes patients to subsequent restenosis.

METHODS

We used in situ hybridization to study the expression of messenger RNA in coronary-atherectomy specimens from 20 patients. Plaque material was hybridized with a probe for the B isoform of human nonmuscle myosin heavy chain, a major nonmuscle myosin isoform in activated, but not quiescent, smooth-muscle cells. Angiographic follow-up data were obtained a mean (+/- SD) of 174 +/- 54 days after atherectomy in 16 of the 20 patients, and the extent of recurrent luminal narrowing was analyzed quantitatively. The presence of restenosis was assessed by exercise thallium scintigraphy in the other four patients.

RESULTS

Atherectomy specimens from 10 of the 20 patients showed hybridization with the probe, defined as the clustering of more than 20 silver grains per cell nucleus in more than 10 nuclei in five high-power fields (x250); specimens from the other 10 patients showed no such hybridization. At follow-up, restenosis had developed in 8 of the 10 patients with positive hybridization results, but was absent in 9 of the 10 patients with negative results (P = 0.007). The degree of late loss in luminal diameter was significantly higher in patients with positive hybridization results than in those with negative results (ratio of late loss to immediate gain after atherectomy, 0.76 +/- 0.3 vs. 0.36 +/- 0.3; P < 0.001).

CONCLUSIONS

We conclude that the expression of the B isoform of nonmuscle myosin heavy chain is increased in some coronary atherosclerotic plaques and that this increase in expression identifies a group of lesions at high risk for restenosis after atherectomy.

Effect of seeding time and density on endothelial cell attachment to damaged vascular surfaces

An in vitro model to facilitate the study of endothelial cell seeding of damaged vascular surfaces has been developed. This may have applications in the study of endothelial seeding of angioplasty and endarterectomy sites. Using this model, the optimum endothelial seeding time for attachment to damaged vascular surfaces should not exceed 30 min and, to achieve confluent cell attachment, a seeding density > 5 x 10(5) cells/cm2 should be used.

Progressive coronary dilation: an angioplasty technique that creates controlled arterial injury and reduces complications

The incidence of dissection or acute closure during coronary angioplasty has remained unchanged in spite of increased operator experience and technologic advances. To test the hypothesis that progressive coronary dilation, that is, predilation of the stenosis with a smaller balloon (2.0 or 2.5 mm) and then maximal dilation with an optimally sized (3.0, 3.25, 3.5, 3.75, or 4.0 mm) balloon may produce controlled injury and thus reduce the incidence of major complications, the procedural success rate and acute complications of progressive coronary dilation were analyzed in 1087 patients (1486 vessels) and compared with other large series. To determine whether progressive coronary dilation would improve success rates for complex lesions, the last 167 vessels were also prospectively characterized by American College of Cardiology/American Heart Association criteria. Of the 1248 vessels with partial occlusions, the success rate was 98.7%. Attempts to dilate total occlusions in 16% (353) of vessels yielded a success rate of 88%. The primary success rates for types A, B, and C lesions were 100%, 97%, and 91%, respectively. Multivessel angioplasty with progressive coronary dilation was done in 32.4% of cases. Acute closure, major dissection, emergency coronary bypass, periprocedural myocardial infarction, and in-hospital death were noted in 1.4%, 1.3%, 0.7%, 0.8%, and 0.09% of the patients, respectively; the incidence was significantly lower than in previously reported series. Mean residual stenosis was 20.0% +/- 10.6%. Thus progressive coronary dilation by controlled injury to the plaque offers a high primary success rate; low residual stenosis; and markedly lower incidence of acute closure, major dissection, emergency coronary bypass, and death in dilation of both simple and complex lesions.

Use of fish oil to prevent coronary angioplasty restenosis

OBJECTIVE

To review the literature investigating the use of fish oil in preventing restenosis postangioplasty (RPA).

DATA SOURCES

An Index Medicus and bibliographic search of the English-language literature pertaining to the use of fish oil in preventing RPA. The key terms used were fish oil, angioplasty, and eicosapentaenoic acid.

STUDY SELECTION AND DATA EXTRACTION

The results of all trials, including abstracts, that were obtained are reviewed and critiqued.

DATA SYNTHESIS

Restenosis of a coronary vessel at the site of angioplasty occurs 30-40 percent of the time. Because fish oil has been theorized to prevent atherosclerosis and because atherosclerotic-like processes are theorized to be involved in RPA restenosis, fish oil has been studied to determine whether it can prevent RPA. Results of such trials have been mixed. Some have observed a reduction in the number of patients with angiographic or clinical evidence of restenosis. Two trials have failed to observe such an effect. Reasons for the differences are unknown. Possible explanations include differences in study design, endpoint parameters, definition of restenosis, and dosing methods of the fish oil. Bleeding was not of significant concern in any of the trials, even when fish oil was combined with antiplatelet therapy.

CONCLUSIONS

Fish oil may be considered for use in patients to prevent RPA. It probably should be continued for only six months following the procedure. Current data suggest that at least 3 g/d of eicosapentaenoic acid and 1 g/d of docosahexaenoic acid should be used. If possible, therapy should be started as soon as it is known that angioplasty will be performed or at least as soon as possible following the procedure. Many patients may not be able to tolerate fish oil because of its gastrointestinal effects.

Excimer laser-facilitated coronary angioplasty. Relative risk analysis of acute and follow-up results in 200 patients

BACKGROUND

Excimer laser coronary angioplasty has been reported to be a promising treatment for complex coronary artery disease. The purpose of this study was to define the predictors of acute success and restenosis after this experimental intervention.

METHODS AND RESULTS

A cohort of 200 consecutive patients had a minimum of 6 months of follow-up evaluation after treatment of 215 coronary stenoses that were carefully selected for excimer laser coronary angioplasty. At the time of the initial procedure, the laser catheter alone produced a residual stenosis of less than or equal to 50% at 119 of 215 lesions (55.4%). For complete dilatation, 87.9% of the lesions required adjunctive balloon angioplasty. Clinical success was achieved in 183 of the 200 patients (91.5%), as indicated by a reduction by at least 20% of the narrowing of the vessel diameter, less than or equal to 50% residual stenosis, and no in-hospital complication. Complications included abrupt closure (5.0%), myocardial infarction (3.5%), bypass surgery (3.0%), perforation (2.0%), and death (0.0%). Logistic regression analysis showed that lesions at vessel bifurcations (success rate, 66%; adjusted odds ratio [OR] = 0.16; p = 0.002) or in tortuous vessels (success rate, 82%; OR = 0.48; p = 0.004) were associated with decreased clinical success. However, acceptable success rates were achieved in patients with lesions in saphenous vein grafts more than 3 years old (success rate, 94%; OR = 1.40; p = 0.75), in ostial lesions (success rate, 100%; OR = 3.36; p = 0.43), and in lesions longer than 10 mm (success rate, 93.5%; OR = 1.50; p = 0.39). Clinical follow-up was available in 197 of the 200 patients (98.5%) a mean of 5.9 +/- 1.9 months after angioplasty, at which time 31.0% of patients had developed symptoms or evidence of ischemia. No patient died during the study. Follow-up angiography was obtained in 83.1% of eligible patients after a mean [+/- SD] of 5.2 +/- 2.0 months. Angiographic restenosis, defined by greater than 50% stenosis, appeared at 78 of 164 lesions (47.6%). By logistic regression analysis, only lesions in saphenous vein grafts were associated with a decreased rate of restenosis (restenosis rate, 20%; OR = 0.18; p = 0.01).

CONCLUSIONS

This analysis, which defines the profile of risk for excimer laser angioplasty, provides a sound basis for rigorous comparison of adjunctive excimer laser with balloon angioplasty for ostial narrowings, long lesions, and saphenous vein graft stenoses.