Development Of Restenosis Research Articles

Abstract 2994: Atherosclerotic Plaque Histology Predicts Restenosis after Carotid Endarterectomy: a Prospective Cohort Study in 500 Patients.

Introduction: Many studies have addressed clinical and angiographic risk factors for restenosis development after vascular interventions, but the composition of the atherosclerotic plaque at the intervention site has not been studied as a determinant of luminal re-narrowing after intervention. The aim of this study was to investigate the association between atherosclerotic plaque histology at baseline and restenosis development after carotid endarterectomy. Methods: Patients undergoing carotid endarterectomy were included in a longitudinal vascular biobank study. After surgical excision, the plaques were subjected to histological examination. The patients were prospectively followed-up with duplex ultrasound to assess restenosis (cut-off points: >50% and >70% renarrowing) one year after the intervention. The risk of restenosis was related to predefined plaque histological characteristics (macrophage and smooth muscle cell infiltration, collagen, calcifications, intra-plaque bleeding, luminal thrombus and lipid core size) adjusted for clinical characteristics (multivariable logistic regression analysis). Measurements of vessel diameter and intima-media thickness were performed using B-mode ultrasound in a subgroup of patients to discriminate between the roles of geometric vascular remodeling and neointima formation during follow-up. Results: In 500 consecutive patients (April 2002 – April 2007), plaque macrophage infiltration and a large lipid core were strongly associated with decreased risk of >50% restenosis (adjusted odds ratio = 0.43 [0.26 – 0.70]; 0.38 [0.19 – 0.70]) and >70% restenosis during follow-up (adjusted odds ratio = 0.36 [0.18 – 0.74]; 0.42 [0.17–1.03]), independent of clinical characteristics. The other histological characteristics were not related with restenosis. Duplex measurements (n=50) showed that vessels holding macrophage rich plaques revealed increased expansive geometric vascular remodeling during 1 year follow-up (+1.19 mm [0.03 – 2.36]). Conclusions: The absence of plaque macrophages and lipid core are powerful independent predictors of restenosis development after carotid endarterectomy. Plaque composition is linked with restenosis via geometric vascular remodeling.

Abstract 3740: Prognostic Significance of Plasma Osteopontin Levels in Patients Undergoing Percutaneous Coronary Intervention

Osteopontin (OPN) mRNA was shown to be highly expressed in atherosclerotic plaques. We reported plasma OPN levels to be high in patients (pts) with coronary artery disease. Moreover, OPN levels were recently shown to be high in acute coronary syndrome. Increased OPN mRNA expression was also shown in rat arteries after balloon injury. OPN transgenic mice showed markedly increased neointimal formation after arterial injury. OPN may play a role in the development of restenosis after percutaneous coronary intervention (PCI). Methods: We investigated the prognostic value of pre-procedural plasma OPN levels by ELISA on restenosis and clinical outcome in 130 pts undergoing PCI, of whom 89 (68%) had bare metal stent. Pts with AMI were excluded. Restenosis was defined as >50% diameter stenosis at follow-up angiography. Pts were followed up for 3 years for major adverse cardiovascular events (MACE) (death, MI, unstable angina, stroke). Results: At 7±3 months after PCI, re-angiography was performed in 91 (70%) pts, of whom 40 had restenosis. Between 40 pts with restenosis and 51 without it, plasma OPN (492±200 vs 482±224 ng/ml) and C-reactive protein (CRP) (median 0.78 vs 0.70 mg/l) levels did not differ. In multivariate analysis, reference diameter and smoking were independent predictors for angiographic restenosis, but OPN or CRP levels were not. During the 3-year follow-up, MACE occurred in 21 pts. Compared with 109 pts without MACE, 21 with it had higher OPN (586±230 vs 438±195 ng/ml, P<0.005) and CRP (1.30 vs 0.70 mg/l, P<0.002) levels. Pts with MACE more often had OPN level >500 ng/ml (62% vs 35%) and CRP >3.0 mg/l (33% vs 12%) than without it (P<0.05). OPN did not correlate with CRP levels. To clarify the association between MACE and OPN, pts were divided into 2 groups by OPN levels. Kaplan Meier analysis showed a lower event-free survival rate in pts with OPN level >500 ng/ml than those without it (P<0.05). In multivariate analysis, both OPN and CRP levels were independent predictors for MACE. Hazard ratios for MACE were 2.9 (95%CI=1.3–5.5) for OPN >500 ng/ml and 4.3 (1.3–14.0) for CRP >3.0 mg/l. Conclusion: Plasma levels of OPN as well as CRP were found to be independent predictors for cardiovascular events in pts undergoing PCI, but they were not predictors for restenosis.

Clinical outcomes of dexamethasone‐eluting stent implantation in ST‐elevation acute myocardial infarction

The aim of our study was to evaluate the safety and midterm clinical results of dexamethasone-eluting stent (DexES) implantation in ST-segment elevation acute myocardial infarction (STEMI). Inflammation plays a pivotal role in both inestabilization of coronary atherosclerotic plaques and development of restenosis after stent placement. Antiinflammatory agents may attenuate those mechanisms and improve clinical outcomes. There is little information about clinical results of DexES and no data are available about their utilization during percutaneous coronary intervention (PCI) in STEMI. Consecutive patients with STEMI that underwent primary or rescue PCI in our institution were treated with DexES. Clinical follow-up with routine realization of noninvasive test for detection of myocardial ischemia and coronariography if necessary, were performed. The objective of the study was to evaluate the rate of MACE (death, reinfarction, or target lesion revascularization) during midterm follow-up. The procedure was successful in 96.7% of cases. There were no in-hospital deaths or reinfarctions. One acute stent thrombosis occurred and no subacute thrombosis were observed. During a mean follow-up period of 384 days, cardiac-related death was 1.1%, there were no reinfarctions or late stent thrombosis and target lesion revascularization rate was 4.2%. We conclude that utilization of DexES for PCI in STEMI is safe and provides good midterm clinical outcomes.

Restenosis following Percutaneous Renal Artery Revascularization

Background/Aims: Restenosis following percutaneous transluminal renal angioplasty (PTRA) remains a concern even in the era of adjuvant stenting. The optimal form of therapy, and particularly the role of repeat PTRA in the treatment of recurrent hypertension associated with renal artery restenosis, is largely unknown. The aims of this study were to determine the risk factors for restenosis and to evaluate the blood pressure outcomes of patients who underwent repeat PTRA. Methods: Clinical and procedural characteristics of 32 patients who developed recurrent hypertension and renal artery restenosis were compared to a control group of patients who maintained renal artery patency and adequate blood pressure control after the first procedure. The groups were matched for sex and initial procedure date. Results: The restenosis group had a mean age of 71 ± 12 years, a female/male ratio of 24/8, an average blood pressure of 179/87 mm Hg, despite three antihypertensive medications, and a serum creatinine level of 1.5 ± 0.4 mg/dl. Repeat PTRA performed for clinically significant restenosis was 10.7 ± 8 months after the first procedure, and 17 of the 32 patients had a measurable blood pressure benefit at last follow-up (177 ± 119 weeks). The development of restenosis was positively associated with body weight (p = 0.003) and body mass index (p = 0.008), but independent of diabetes mellitus, hyperlipidemia, or statin therapy. Of the 15 patients who failed the second procedure, 4 went on to have third PTRA, none of whom had sustained benefit. Conclusions: An increased body mass index is associated with restenosis following initial PTRA. Patients with restenosis can be treated successfully with repeat PTRA which provides sustained improvement in blood pressure control in approximately half of these patients.

Endoluminal Therapy in Patients with Peripheral Arterial Disease: Prospective Assessment of Quality of Life in One Hundred Ninety Patients

Conclusion: Successful peripheral endovascular revascularization (PER) results in improved quality of life for both patients with claudication and critical limb ischemia. Summary: The authors evaluated prospectively changes in quality of life in 190 patients before PER and at 1, 3, 6, and 12 months after treatment. Quality of life was assessed using the Medical Outcomes Study Short Form-36 (SF-36). The authors evaluated the effects of PER and quality of life in both claudication and critical limb ischemia patients. The influence of lesion location, restenosis, and additional interventions on quality of life was also evaluated. Data were available in 136 patients at 6 months and in 103 patients at 12 months. Patients with technically successful primary interventions, defined as residual stenosis <30%, when compared with patients with technically unsuccessful interventions, defined as residual stenosis >30%, showed significantly lower scores for bodily pain and physical functioning at 1 month, for bodily pain at 3 months, and for bodily pain and social functioning at 6 months. Patients with restenosis, followed by successful secondary intervention, showed numerous differences in SF-36 scores at 1, 3, and 6 months compared with patients who underwent a primary intervention that was initially successful. At 12 months, patients with restenosis, followed by secondary intervention, had lower scores for vitality, mental health, and general health perception. Patients with a significant stenosis diagnosed during follow-up with no secondary intervention had lower scores for physical functioning, vitality, bodily pain, and general health perception at 1 month compared with patients without stenosis. They also had lower scores for bodily pain, general health perception at 3 months, lower scores for physical functioning and social functioning at 6 months, and lower scores for physical function, vitality, social function, and bodily pain at 12 months. Patients who had deterioration in their clinical symptoms had significantly lower scores for all SF-36 domains at 1, 3, and 6 months. They also had lower scores for all domains at 12 months, except those for role limitations due to emotional problems and social function. Follow-up examinations were performed to objectively assess stenosis in 93 patients (49%) and a significant restenosis was detected in 60.2%. In 43 cases, the restenosis was at the site of intervention, and new lesions were found in the ipsilateral leg in five cases and in the contralateral leg in eight cases. Development of restenosis was related to lower scores at 1 month in the domains of physical functioning, role limitations due to emotional problems, vitality, mental health, bodily pain, and general health perception. At 3 months, restenosis was associated with lower scores in terms of vitality, bodily pain, and general health perception. At 6 months, lower scores were observed in patients with restenosis for role limitations due to emotional problems, vitality, bodily pain, and general health perception. At 12 months, restenosis was associated with lower scores for physical functioning, vitality, mental health, social function, bodily pain, and general health perception. Patients with claudication when compared with patients with critical limb ischemia showed lower scores for physical functioning, role limitations due to physical problems, role limitations due to emotional problems, vitality, and bodily pain at baseline. At 12 months after the initial intervention, no significant difference was noted in scores between claudication patients and patients with critical limb ischemia. Comment: This study is difficult to understand. It is certainly expected that many of the peripheral interventions would eventually fail and that failure of the peripheral intervention would be associated with lower SF-36 scores in many domains. It also is understandable that patients with critical limb ischemia would have lower SF-36 scores than patients with claudication. However, it makes no sense that patients with claudication and critical limb ischemia should have similar SF-36 scores at 12 months. It is unclear whether patients with critical limb ischemia have substantially improved after their intervention or that patients with claudication substantially worsened after their intervention, or a combination of both.

High P-selectin expression and low CD36 occupancy on circulating platelets are strong predictors of restenosis after coronary stenting in patients with coronary artery disease

Recent studies have shown that circulating platelets play an important role in the development of restenosis early after coronary stent implantation. We investigated P-selectin expression and CD36 blockade on platelets by flow cytometry in 48 consecutive patients who underwent coronary stenting. P-selectin expression was significantly higher 1 day after stenting in patients who had restenosis (n = 15) than in those who had no restenosis (n = 28), and the odds ratio for restenosis in patients with high P-selectin levels (MFI > 6.5) was 11.67 (P < 0.001) as compared with patients who had intermediate and low P-selectin levels. CD36 blockade was assessed with the use of two anti-CD36 antibodies, OKM5 and GS95 (our new anti-CD36 antibody), the binding of which indicates total CD36 amount and free CD36 unoccupied by lipid-related ligands, respectively. Binding of OKM5 to platelets was similar before and after stenting in both groups. CD36 blockade on platelets was seen 1 day after stenting in the non-restenosis group, and the odds ratio for restenosis in patients without CD36 blockade [GS95 binding ratio >0.8 as compared with binding before stenting] on day 1 was 28.60 (P < 0.001). P-selectin expression and unoccupied CD36 on platelets shortly after stenting may be strong predictors of post-stent restenosis.

Patterns of Kinase Activation Induced by Injury in the Murine Femoral Artery

Intimal hyperplasia remains the principal lesion in the development of restenosis after vessel wall injury. Cell signaling in vascular smooth muscle cells remains a potential molecular target to modulate the development of intimal hyperplasia. The aim of this study was to define a baseline pattern of histological changes and kinase activation in a murine model. The murine femoral wire injury model was used in which a microwire was passed through a branch of the femoral artery and used to denude the common femoral artery. Pluronic gel was used to apply mitogen-activated protein kinases (MAPK) inhibitors (PD98059, SB230580, and SP600125) on the exterior of the vessels. Specimens were perfusion-fixed and sections were stained for morphometry using an ImagePro system. Additional specimens of femoral artery were also harvested and snap frozen for Western blotting and zymography to allow for the study of kinase and protease activation. Contralateral vessels were used as controls. The injured femoral arteries developed intimal hyperplasia, which is maximal at 28 days and does not change substantially between day 28 and day 56. Sham-operated vessels did not produce such a response. Cell apoptosis peaked within 3 days and cell proliferation peaked at 7 days after injury. There is a time-dependent increase in kinase activity immediately after injury. MEK1/2 activation peaks at 20 min after injury and is followed by a peak in extracellular signal-regulated kinase-1/2 activation at 45 min. The stress kinases p38(MAPK) and JNK peak between 10 and 20 min. Activation of akt is later at 45 min and 120 min and activation of p70S6K was biphasic. There was a time-dependent increase in uPA/PAI-1 expression and activity after injury. Local application of MAPK inhibitors (PD98059, SB230580, and SP600125) within a pluronic gel reduced respective MAPK activity, decreased cell proliferation and enhanced cell apoptosis, increased PAI-1, and decreased uPA expression and activity; at 14 days there was a decrease in intimal hyperplasia. These data demonstrate that femoral wire injury in the mouse induces a consistent model of intimal hyperplasia and that it is associated with a time dependent increase in signaling kinase activity. Interruption of these pathways will interrupt the uPA/PAI-1 pathway and decrease intimal hyperplasia development. Accurate characterization of cell signaling is a necessary step in the development of molecular therapeutics.

Early Rise in Serum VEGF and PDGF Levels Predisposes Patients With a Normal MBL2 Genotype to Restenosis After Eversion Endarterectomy

Recently we found that the incidence of restenosis after carotid endarterectomy was significantly higher in patients homozygous for the normal genotype of mannose-binding lectin (MBL2) than in with patients with MBL2 variant genotypes. Several growth factors are also known to contribute to restenosis. Therefore, we investigated whether early postoperative changes in serum vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and platelet-derived growth factor (PDGF) concentrations and MBL2 genotypes interact in the development of restenosis. Eighty-two patients who underwent carotid eversion endarterectomy and were followed up by carotid duplex scan sonography for 14 months were studied. Growth factors were measured preoperatively and 4 days after surgery. Pronounced significant increases in both VEGF and PDGF predicted restenosis but only in patients who were homozygous for the normal MBL2 genotype. In this group, the adjusted odds ratios of restenosis at 14 months in patients with high versus low early VEGF and PDGF increases were 27.73 (2.42 to 317.26) and 9.23 (1.45 to 58.70), respectively. These findings indicate that the development of restenosis depends on both complement activation regulated by the MBL2 gene and pathologic processes leading to enhanced production of VEGF and PDGF during the very early postoperative period.

Numerical study of hemodynamics comparison between small and large femoral bypass grafts

AbstractThe geometry factors have prominent impacts on the flow patterns of bypass graft. In order to clarify the influence of graft diameter on the hemodynamics of femoral bypass graft, the pulsatile blood flows in three bypassing models with different graft diameters were simulated with finite‐element method. The temporal–spatial distributions of flow patterns, pressure drops, and wall shear stresses were depicted and compared. The results indicated that femoral artery bypassed with a large graft demonstrates relatively better and more profitable hemodynamic phenomena with large longitudinal velocity, uniform wall shear stress, and small wall shear stress gradient. The large model may be effective in decreasing the probability of the initiation and development of postoperative intimal hyperplasia and restenosis. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Adiponectin incompletely prevent MCP-1-dependent restenosis after percutaneous coronary intervension in patients with coronary artery disease

Some factors play pathogenic roles in the development of restenosis after percutaneous coronary intervention (PCI). We measured and compared the ratio of elevated levels of monocytic chemotactic peptide-1 (MCP-1), regulated on activation normally T-cell expressed and secreted (RANTES), soluble (s) P-selectin, sE-selectin and adiponectin after PCI. Plasma levels of chemokines and soluble markers were measured before and 30 days after PCI in 96 patients (69 males and 27 females, aged 63 +/- 9 years) who underwent PCI and who had repeated angiograms at a 6-month follow-up. In addition, we carried out the basic study of the tissue factor expression on monocytic cell line (THP-1) by MCP-1. Restenosis occurred in 33 (34.4%) patients. A significant and time-dependent increase in MCP-1 was observed in the restenosis group. However, there were no significant differences in RANTES, sP-selectin, and sE-selectin levels with or without restenosis. Adiponectin levels in patients with coronary artery disease were significantly lower than levels in normal controls. However, adiponectin levels were no different at baseline between patients with or without restenosis. MCP-1 did not induce the expression of tissue factor on THP-1. However, the recombinant sCD40 ligand-induced expression of tissue factor on THP-1 was enhanced by the addition of MCP-1. These findings suggest that restenosis development after PCI in patients with coronary artery disease may involve the participation of MCP-1 after PCI, and adiponectin incompletely prevent this MCP-1-dependent restenosis.

Association of Circulating Transforming Growth Factor beta, Tumor Necrosis Factor alpha and Basic Fibroblast Growth Factor with Restenosis after Transluminal Angioplasty

To assess prospectively the early time course of Transforming Growth Factor beta-1 (TGFbeta-1), basic Fibroblast Growth Factor (bFGF) and Tumor Necrosis Factor alpha (TNFalpha) as possible contributors to restenosis development after angioplasty. Prospective Study. The levels of the soluble forms of these factors in the early response to Percutaneous Transluminal Angioplasty (PTA) in the arteries of the lower limb were prospectively assessed. 32 patients with peripheral arterial occlusive disease (PAOD), presenting with intermittent claudication (Fontaine stage IIb) were scheduled for angioplasty treatment. Serum levels of TGFbeta-1, TNFalpha and bFGF were assessed before intervention, 15 and 60 minutes after, 24 hours after as well as 2 and 4 weeks after intervention. We compared the distribution patterns between patients treated with balloon angioplasty and patients who required secondary stent implantation. Endpoint was the development of restenosis within 6 months after interventional treatment, defined as a lumen diameter reduction of more than 50% by ultrasound measurement compared to the result after PTA. The patients who later developed restenosis had significantly higher levels of TGFbeta-1 at 15 minutes, 24 hours and 2 weeks after PTA (p<0.05). TNFalpha and bFGF were only detected in a few patients and no significant change of serum levels was observed. The results demonstrate a possible role of TGFbeta-1 in the formation of restenosis after PTA.

Cutting-balloon angioplasty effectively facilitates the interventional procedure and leads to a low rate of recurrent stenosis in ostial bifurcation coronary lesions: A subgroup analysis of the NICECUT multicenter registry

Background Displacement of plaque is a major concern during coronary intervention of ostial bifurcation lesions. For this reason, angioplasty involves complex stenting procedures, which may trigger development of restenosis in a previously non-diseased parent vessel. Objectives To examine, whether plaque displacement may be prevented by scoring atherosclerotic plaque with a cutting-balloon (CB) stand-alone procedure. Methods Data of patients with Duke E and B type ostial bifurcation lesions (≥ 70% stenosis involving a diagonal and/or marginal branch > 2 mm deriving from a non-diseased parent vessel), who were treated with CB as stand-alone procedure within the prospective NICECUT multicenter trial were analyzed. Primary endpoint was the rate of binary stenosis and target lesion revascularization (TLR). Secondary endpoints were procedural success and major adverse cardiac events (MACE) at 6-months follow-up. Results 63 out of 65 lesions (56 patients) were successfully amenable to treatment with CB (96.4% procedural success). 76.9% of patients were successfully treated with CB as a stand-alone procedure, while provisional stenting was necessary in 23.1%. At follow-up, binary stenosis was found in 23.2%, among the total population. Total rate of TLR and MACE were 7.7% and 3.6%, respectively, compared to 4.0% and 2.0% in patients for whom CB stand-alone procedure was feasible, while it was 20.0% and 6.7% for stented lesions. Conclusions CB angioplasty as a stand-alone procedure may facilitate interventional treatment of ostial bifurcation lesions and may help to avoid complex stenting procedures. It is associated with a low rate of binary stenosis and TLR.

Time-dependent 3D simulations of the hemodynamics in a stented coronary artery

Stenting is becoming the major interventional cardiology procedure worldwide. However restenosis remains a major limitation to the effectiveness of stents. Alterations to the local hemodynamics in the stented segment of the artery could be a potential factor in the development of in-stent restenosis. The characterization of wall shear stress and of blood flow patterns in a stented artery is therefore necessary for a good understanding of the role of hemodynamics in the development of in-stent restenosis. We have used a time-dependent 3D numerical model of a stented coronary artery to study the characteristics of the blood flow and the shear stress distribution. Our results show that the presence of the stent produces significant secondary flow that is limited to an annulus in the near wall region. Low shear stress zones were localized in the vicinity of the struts while the tips of the struts exhibited high values of shear stress. These results support the hypothesis that local hemodynamics may affect the development of in-stent restenosis and could influence the choice of stent geometries for future stent designs.

Drug-Eluting Stent and Coronary Thrombosis

Although rare, stent thrombosis remains a severe complication after stent implantation owing to its high morbidity and mortality. Since the introduction of drug-eluting stents (DES), most interventional centers have noted stent thrombosis up to 3 years after implantation, a complication rarely seen with bare-metal stents. Some data from large registries and meta-analyses of randomized trials indicate a higher risk for DES thrombosis, whereas others suggest an absence of such a risk. Several factors are associated with an increased risk of stent thrombosis, including the procedure itself (stent malapposition and/or underexpansion, number of implanted stents, stent length, persistent slow coronary blood flow, and dissections), patient and lesion characteristics, stent design, and premature cessation of antiplatelet drugs. Drugs released from DES exert distinct biological effects, such as activation of signal transduction pathways and inhibition of cell proliferation. As a result, although primarily aimed at preventing vascular smooth muscle cell proliferation and migration (ie, key factors in the development of restenosis), they also impair reendothelialization, which leads to delayed arterial healing, and induce tissue factor expression, which results in a prothrombogenic environment. In the same way, polymers used to load these drugs have been associated with DES thrombosis. Finally, DES impair endothelial function of the coronary artery distal to the stent, which potentially promotes the risk of ischemia and coronary occlusion. Although several reports raise the possibility of a substantially higher risk of stent thrombosis in DES, evidence remains inconclusive; as a consequence, both large-scale and long-term clinical trials, as well as further mechanistic studies, are needed. The present review focuses on the pathophysiological mechanisms and pathological findings of stent thrombosis in DES.

Complement Component C5a Predicts Restenosis After Superficial Femoral Artery Balloon Angioplasty

To investigate whether balloon angioplasty of the superficial femoral artery (SFA) increases serum levels of C5a and whether C5a predicts risk of restenosis. C5a antigen was measured at baseline and 8 hours after intervention in 131 consecutive patients (76 women; median age 72 years) with intermittent claudication who underwent successful primary SFA balloon angioplasty. Patients were followed for a median 10 months [interquartile range (IQR) 6 to 14] for the occurrence of >50% restenosis by duplex ultrasound. Median C5a levels increased significantly from 39.7 ng/mL (IQR 27.8 to 55.0) at baseline to 53.8 ng/mL (IQR 35.6 to 85.1, p<0.001) 8 hours post intervention. During the follow-up period, 70 (53%) patients developed restenosis. Increasing levels of C5a (quartiles) at baseline were significantly associated with an increased risk for restenosis (p=0.0092). Adjusted hazard ratios (95% confidence intervals) for restenosis with increasing quartiles of baseline serum C5a levels were 1.24 (0.60 to 2.58), 1.93 (0.95 to 3.93), and 2.08 (1.02 to 4.21), respectively, compared to the lowest quartile. This effect was independent of nonspecific inflammation as reflected by plasma levels of C-reactive protein. Inflammatory mechanisms play a major role in the development of restenosis after angioplasty. The complement component C5a exerts strong chemotactic and proinflammatory effects. Enhanced complement activation prior to PTA, as measured by higher levels of C5a, was significantly associated with restenosis after SFA balloon angioplasty. Pathways of complement inhibition thus may be worth investigating with respect to improving patency rates.

P288: Patterns of kinase activation induced by injury in the murine femoral artery

Background: Intimal hyperplasia remains the principal lesion in the development of restenosis after vessel wall injury. Cell signaling in vascular smooth muscle cells (VSMCs) remains a potential molecular target to modulate the development of intimal hyperplasia. Transgenic murine strains allow for a detailed examination of the role of individual molecules on biological outcomes. Purpose: The aim of this study is to define a baseline pattern of both histological changes and kinase activation in a murine model of intimal hyperplasia. Methods: The murine femoral wire injury model was employed in which a micro wire is passed through a branch of the femoral and used to denude the common femoral artery. Specimens were perfusion-fixed and sections were stained with H&E and Movat’s stain such that morphometry could be performed using an ImagePro system. Additional specimens of femoral artery were also harvested and snap frozen for western blotting to allow for the study of MAPK activation. Contrallateral vessels were used as controls. Results: The injured femoral arteries develop intimal hyperplasia, which is maximal at 28 days and does not change substantially between day 28 and day 56. Sham operated vessels did not produced such a response. Using PCNA as a marker of cell proliferation, we identified a peak in VSMC proliferation at 3-5 days after injury. There was a time dependent increase in kinase activity immediately after injury. MEK1/2 activation peaks at 10 mins after injury and is followed by a peak in ERK1/2 activation at 20 mins. The stress kinases p38MAPK and JNK peak between 10 and 20 mins. Activation of akt is later at 45 and 120 mins and activation of p70S6K occurs at 180 mins after injury. Conclusions: These data demonstrate that femoral wire injury in the mouse induces a consistent model of intimal hyperplasia that is associated with a time dependent increase in signaling kinase activity. Accurate characterization of cell signaling is a necessary step in the development of molecular therapeutics.

P293: Sphingosine-1-phosphate induced smooth muscle cell migration requires receptor tryosine kinase receptor transactivation

Background: The development of restenosis involves an integrative program of cell proliferation, migration and extracellular matrix degradation via Matrix Metalloproteinases (MMPs). The bioactive sphingolipid metabolite, sphingosine-1-phosphate (S-1-P), has been implicated in cell migration by regulating G-protein dependent signaling pathways such as the p38 and ERK1/2 MAPK pathways. Recent studies suggest that S-1-P may also function as an integrator molecule, linking growth factor receptors to cell migration.

The association of P-selectin glycoprotein ligand-1 VNTR polymorphisms with coronary stent restenosis

P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1) regulate the initial interactions between leukocytes, activated platelets and endothelial cells. Recently, a variable number of tandem repeats (VNTR) polymorphism in PSGL-1 gene affecting the length of the extracellular domain of PSGL-1 and the distance of the P-selectin binding site to the cell surface has been described. There are limited numbers of studies reporting PSGL-1 polymorphism might affect the inflammatory response and thrombosis. We explored the association between PSGL-1 VNTR polymorphisms (especially AB genotype that has the most deformed configuration of the binding site) and the development of coronary stent restenosis and stent thrombosis in patients with coronary artery disease (CAD). Eighty-seven patients with in-stent restenosis and 93 patients with patent coronary stents were included into the study. The distributions of age, gender, hypertension, diabetes, smoking, total cholesterol and triglyceride levels were similar between the groups. Genomic DNAs were obtained by standard methods from whole blood samples. Specific primers were used to amplify PSGL-1 gene by polymerase chain reaction (PCR). Three alleles and 5 different genotypes were detected. In the in-stent restenosis group; allele frequencies were 79.5% for A allele, 18.1% for B allele and 2.4% for C allele and in the patent stent group; allele frequencies were 79.3% for A allele, 20.1% for B allele and 0.6% for C allele. The allele frequencies were similar between the in-stent restenosis group and patent stent group (P = 0.97 for A allele, P = 0.73 for B allele and P = 0.19 for C allele). Genotype distributions were also similar between the groups. There were not any significant associations between PSGL-1 AB genotype and stent restenosis (31.3% vs. 27.2%, P = 0.54), repetitive stent restenosis (33.3% vs. 28.8%, P = 0.82) or in-stent thrombosis (44.4% vs. 28.2%, P = 0.37). In neither male patients nor female patients, there was any significant association between AB genotype and restenosis (32.2% vs. 24.3% P = 0.31 and 29.2% vs. 38.9% P = 0.51, respectively). However, among patients with a family history of early CAD, significantly higher percentage of AB genotype was found in those with stent restenosis (41.4% vs. 18.8%, P = 0.03). No significant association was found between PSGL-1 VNTR polymorphisms and in-stent restenosis. However, in patients with a family history of early CAD presence of PSGL-1 AB genotype might increase the risk of in-stent restenosis.

Metabolic Syndrome and Risk of In-Stent Restenosis: Clinical Outcomes in Patients Undergoing Percutaneous Coronary Intervention

Background and Objectives: Patients with metabolic syndrome (MS) have an increased risk of cardiovascular events. However, only limited studies are available on the effect of MS on restenosis and on the clinical outcome of patients undergoing percutaneous coronary intervention (PCI). The aim of this study is to assess the role of MS in the development of restenosis, and risk of a 6-month major adverse cardiac event (MACE) and a 12-month MACE, as well as the difference of outcome between the use of bare metal stents (BMSs) and the use of drug eluting stents (DESs). Subjects and Methods: This is a one center, retrospective study. The study population comprised 151 patients undergoing percutaneous coronary intervention (PCI) with BMSs and 200 patients undergoing PCI with DESs. The study population was classified into two groups of patients with MS and patients without MS. Results: The baseline clinical characteristics were similar in the two groups (with or without MS) except for hypertension, diabetes, body mass index, triglyceride level and high-density lipoprotein level. The frequency of in-stent restenosis of the patients that were implanted with BMSs or DESs was not different between two groups, based on a 6 month follow-up quantitative coronary angiographic analysis (BMSs: 30% vs 22.2%, p= 0.352; DES: 3.3% vs 2.2%, p=0.76; for patients with and without MS, respectively). The percent of patients with a 6-month MACE for patients implanted with BMSs was not statistically different for patients with or without MS (30% vs 22.2%, p=0.352) but the percent of patients with a 12-month MACE showed a statistically significant higher level for the MS group (38.6% vs 23.5%, p=0.044). The percent of patients with a 6-month MACE for patients implanted with DESs was also not statistically different between two groups (5.8% vs 1.7%, p= 0.123). Conclusion: Patients with MS undergoing BMSs or DESs implantation do not show higher levels of in-stent restenosis and levels of a 6-month MACE. The number of 12-month MACEs of patients implanted with BMSs is statistically higher, but the number of 6-month MACEs of patients implanted with DESs is not different for the MS group. We conclude that MS is not risk factor of in-stent restenosis in PCI but MS may influence the long-term clinical outcome in patients undergoing PCI. (Korean Circ J 2007;37:567-573)

Inhibition of restenosis development after mechanical injury: a new field of application for malononitrilamides?

Aims: Since the high rate of restenosis after percutaneos transluminal coronary angioplasty limited its long-term success, the implementation of locally-delivered antiproliferative/immunosuppressive agents became advantageous. In this study, the efficacy of the malononitrilamide FK778 to prevent vascular smooth muscle cell (SMC) migration/proliferation, and vascular fibrosis, the key events in restenosis development using in-vivo and in-vitro studies was investigated.