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e21715 Background: Important questions have been raised about whether real world data (RWD) can be relied upon to support clinical and regulatory decision-making. The aims of this study were to assess overall survival (OS), time-to-treatment (TTT), follow-up time, and treatment pathways in metastatic non-small cell lung cancer (mNSCLC) patients treated with programmed cell death protein 1 inhibitors (PD-1i). Methods: Two mNSCLC cohorts were identified in a US based EMR network. To explore treatment pathways, patients had to have an advanced (stage 3/4) diagnosis of NSCLC confirmed by a tumor registry record. A line of treatment (LOT) was defined as a PD-1i or chemotherapy taken within 30 days. OS, time to treatment, and follow-up time were also calculated. In another cohort patients had to have at least one PD-1i (pembrolizumab, nivolumab, durvalumab, or atezolizmab) and an oncology treatment within 3 months of an advanced stage diagnosis. OS was calculated using Kaplan-Meier analysis and stratified by time after nivolumab approval, quarter of PD-1i initiation, and line of therapy of first PD-1i. Patient characteristics were defined by ICD, CPT, LOINC, and RxNorm terminology. Results: Median overall survival was found to be 213 days (IQR 109, 425.25). In the treatment pathways analysis, 58.3% of patients started on a non-PD-1i chemotherapy as an initial line of treatment for mNSCLC. PD-1i was the most common second line treatment and 41.4% of patients who started on a non-PD-1i therapy switched to a PD-1i as their second line therapy. Median time from advanced diagnosis to PD-1i inhibitor initiation (9.6 months (IQR 3.45, 21.45)) and median structured follow-up times from advanced diagnosis (21.87 months (IQR 11.94, 38.97)) and from inhibitor initiation (8.71 months (3.06, 17.26)) were comparable to results found in other RWD. Conclusions: Overall survival, time to treatment, and other outcomes were consistent with comparable RWD sources, (Stewart M, 2019; Sean K 2018) regardless of treatment timeframe. We demonstrated that our real world evidence based approach provides a robust method for analyzing clinical outcomes, supporting the validity of real world data to complement clinical trials and inform clinical decisions.

Background Enumeration of circulating tumor cells (CTCs) isolated from the peripheral blood of breast cancer patients holds promise as a clinically relevant, minimally invasive diagnostic test. However, CTC utility has been limited as a prognostic indicator of survival by the inability to stratify patients beyond general enumeration. In comparison, histological biopsy examinations remain the standard method for confirming malignancy and grading malignant cells, allowing for cancer identification and then assessing patient cohorts for prognostic and predictive value. Typically, CTC identification relies on immunofluorescent staining assessed as absent/present, which is somewhat subjective and limited in its ability to characterize these cells. In contrast, the physical features used in histological cytology comprise the gold standard method used to identify and preliminarily characterize the cancer cells. Here, we superimpose the methods, cytologically subtyping CTCs labeled with immunohistochemical fluorescence stains to improve their prognostic value in relation to survival. Methods In this single-blind prospective pilot study, we tracked 36 patients with late-stage breast cancer over 24 months to compare overall survival between simple CTC enumeration and subtyping mitotic CTCs. A power analysis (1-β = 0. 9, α = 0.05) determined that a pilot size of 30 patients was sufficient to stratify this patient cohort; 36 in total were enrolled. Results Our results confirmed that CTC number is a prognostic indicator of patient survival, with a hazard ratio 5.2, p = 0.005 (95 % CI 1.6–16.5). However, by simply subtyping the same population based on CTCs in cytological mitosis, the hazard ratio increased dramatically to 11.1, p

Dietary flaxseed meal reduces proteinuria and ameliorates nephropathy in an animal model of type II diabetes mellitus.BackgroundEvidence is emerging that varying the type or source of dietary protein intake can have beneficial effects on chronic renal disease. Consumption of soybean and soy-based food products, as the source of plant protein, can retard the development and progression of chronic renal disease. We studied the obese spontaneously hypertensive/NIH-corpulent (SHR/N-cp) rat, a model of obesity and type II diabetes mellitus that consistently develops nephropathy resembling diabetic nephropathy. We specifically sought to determine whether changing the source of protein intake from animal protein, casein, to plant protein in the form of either soy protein concentrate or flaxseed protein in the diet has a different impact on renal function and nephropathy in this model.MethodsMale obese SHR/N-cp rats were randomly assigned to one of three diets containing either 20% casein, 20% soy protein concentrate, or 20% flaxseed meal. Except for the protein source, all three diets were identical and contained similar amounts of protein, fat, carbohydrates, minerals, and vitamins. All animals were maintained on these diets for 6months. At the end of the study, blood sampling and 24-hour urine collections were performed for renal functional measurements, and the kidneys were harvested and examined for histologic evaluation.ResultsAll three groups had similar amounts of food intake and body weight gain and exhibited fasting hyperglycemia and hyperinsulinemia. Plasma glucose levels did not differ among the three groups, but plasma insulin concentration was significantly lower in rats fed flaxseed meal than those fed either casein or soy protein concentrate. Mean plasma creatinine, creatinine clearance, and urinary urea excretion also did not differ significantly between the three groups. By contrast, urinary protein excretion was significantly lower (P < 0.01) in rats fed flaxseed than in rats fed either casein or soy protein concentrate. Morphologic analysis of renal structural lesions showed that the percentage of abnormal glomeruli with mesangial expansion and the tubulointerstitial score (an index of severity of tubulointerstitial damage) were significantly reduced in rats fed flaxmeal compared to those fed casein or soy protein concentrate.ConclusionWe conclude that dietary protein substitution with flaxseed meal reduces proteinuria and glomerular and tubulointerstitial lesions in obese SHR/N-cp rats and that flaxseed meal is more effective than soy protein in reducing proteinuria and renal histologic abnormalities in this model. The reduction in proteinuria and renal injury was independent of the amount of protein intake and glycemic control. Which dietary component(s) present in flaxseed meal is (are) responsible for the renal protective effect remains to be determined.

ObjectivesWe evaluated the long-term influence of intramural delivery of advanced c-myc neutrally charged antisense oligonucleotides (Resten-NG) on neointimal hyperplasia after stenting in a pig model.BackgroundNeointimal hyperplasia after percutaneous coronary interventions is one of the key components of the restenotic process. The c-myc is a critical cell division cycle protein involved in the formation of neointima.MethodsIn short-term experiments, different doses (from 500 μg to 5 mg) of Resten-NG or saline were delivered to the stent implantation site with an infiltrator delivery system (Interventional Technologies, San Diego, California). Animals were euthanized at 2, 6 and 18 h after interventions, and excised vessels were analyzed for c-myc expression by Western blot. In long-term experiments, either saline or a dose of 1, 5 or 10 mg of Resten-NG was delivered in the same fashion, and animals were euthanized at 28 days after the intervention.ResultsWestern blot analysis demonstrated inhibition of c-myc expression and was dose dependent. Morphometry showed that the intimal area was 3.88 ± 1.04 mm2in the control. There was statistically significant reduction of intimal areas in the 5 and 10 mg groups (2.01 ± 0.66 and 1.95 ± 0.91, respectively, p < 0.001) but no significant reduction in the 1 mg group (2.81 ± 0.56, p > 0.5) in comparison with control.ConclusionsThis study demonstrated that intramural delivery of advanced c-myc neutrally charged antisense morpholino compound completely inhibits c-myc expression and dramatically reduces neointimal formation in a dose dependent fashion in a porcine coronary stent restenosis model, while allowing for complete vascular healing.

Myointimal hyperplasia after percutaneous transluminal coronary angioplasty (PTCA) is a key component of the process of restenosis. The c-myc is a critical cell-cycle division protein involved in the formation of neointima. We evaluated the long-term impact of local delivery of c-myc neutrally charged antisense oligonucleotides (Resten-NG) on myointimal hyperplasia after PTCA in a rabbit model. PTCA was performed in the iliac arteries of 25 New Zealand white rabbits, using a Transport catheter at 8 atm for 30 sec, three times; 500 microg Resten-NG (n = 11) or saline (n = 14) was delivered to the PTCA site at 2 atm with the outer balloon for 2 min. The diet was supplemented with 0.25% cholesterol for 10 days before and 60 days after PTCA. Angiography was performed at harvest, and vessels were fixed in formalin, processed, and stained with hematoxylin and eosin (H&E) and Movat. Quantitative angiography showed that local delivery of antisense c-myc at PTCA reduced late luminal loss from 1.8 +/- 0.30 mm in control animals to 0.90 +/- 0.30 mm in the treatment group (P = 0.001). Histological analysis by planimetry showed that intimal areas were 1.67 +/- 0.44 mm(2) and 0.82 +/- 0.32 mm(2) in the control and antisense delivery groups, respectively (P < 0.05). We conclude that local delivery of Resten-NG inhibited myointimal hyperplasia after PTCA in cholesterol-fed rabbits for up to 60 days.

OBJECTIVES The objectives of this study were 1) to improve the attachment of reimplanted endothelial cells (EC) using a fibrin glue, and 2) to assess the impact of endothelial reseeding on restenosis eight weeks after balloon angioplasty. BACKGROUND A possible mechanism contributing to restenosis after balloon angioplasty is the loss of the EC lining. Previous attempts to reseed EC had little effect due to rapid loss of the seeded cells. METHODS Twelve atherosclerotic rabbits were subjected to angioplasty of iliac arteries and reseeding procedure. One iliac artery was subjected to EC/glue reconstruction and a contralateral site to EC seeding without glue. The animals were sacrificed after 4 h. In another series 12 rabbits were treated in the same fashion and were restudied at eight weeks. Additionally, in 10 animals one iliac was subjected to glue treatment, and another served as control. RESULTS Histological examination demonstrated the ability of this method to reattach the EC/glue matrix circumferentially to 68.0 ± 6.7% of the arterial wall in comparison with 13.5 ± 3.9% reattachment after EC seeding. Morphometry at eight weeks showed that the lumen area was significantly greater in the EC/glue group (1.23 ± 0.35 mm2) than in the EC seeding alone (0.65 ± 0.02 mm2) and 0.72 ± 0.41 mm2 in the glue group. This was principally accounted for by the statistically significant differences in the intimal area (0.76 ± 0.18 mm2 vs. 1.25 ± 0.26 mm2 and 1.01 ± 0.53 mm2, respectively). CONCLUSIONS The attachment of EC after angioplasty can be greatly improved with fibrin glue matrix. The near 70% endothelial coverage achieved by this method resulted in a significant reduction of restenosis in atherosclerotic rabbit.

Objective. To relate local arterial geometry with markers that are thought to be related to plaque rupture. Background. Plaque rupture often occurs at sites with minor luminal stenosis and has retrospectively been characterized by colocalization of inflammatory cells. Recent studies have demonstrated that luminal narrowing is related with the mode of atherosclerotic arterial remodeling. Methods. We obtained 1,521 cross section slices at regular intervals from 50 atherosclerotic femoral arteries. Per artery, the slices with the largest and smallest lumen area, vessel area and plaque area were selected for staining on the presence of macrophages (CD68), T-lymphocytes (CD45RO), smooth muscle cells (alpha-actin) and collagen. Results. Inflammation of the cap or shoulder of the plaque was observed in 33% of all cross sections. Significantly more CD68 and CD45RO positive cells, more atheroma, less collagen and less alpha-actin positive staining was observed in cross sections with the largest plaque area and largest vessel area vs. cross sections with the smallest plaque area and smallest vessel area, respectively. No difference in the number of inflammatory cells was observed between cross sections with the largest and smallest lumen area. Conclusion. Intraindividually, pathohistologic markers previously reported to be related to plaque vulnerability were associated with a larger plaque area and vessel area. In addition, inflammation of the cap and shoulder of the plaque was a common finding in the atherosclerotic femoral artery.

Abstract Luminal stenosis can be based on large atherosclerotic plaques in compensatory enlarged segments or on relatively little plaques in shrunken segments. In the present study, the contribution of plaque formation and remodeling to luminal narrowing was compared among six types of arteries prone to symptomatic atherosclerosis. Cross-sections (n=5195) were obtained at regular intervals from 329 arteries. For each artery, the cross-section that contained the least amount of plaque was considered to be the reference. For each cross-section, the percentage of lumen area decrease was expressed as a percentage of the lumen area at the reference site (luminal stenosis). Similarly, the area encompassed by the internal elastic lamina (IEL area) was expressed as a percentage of the IEL area at the reference site (relative IEL area). All cross-sections were categorized in three groups: relative IEL area >105% (enlargement), 95% to 105% (no remodeling), and P

Geometric remodeling in atherosclerosis and restenosis comprises a change of the total arterial circumference that, together with plaque growth or neointima formation, determine the lumen of the artery. The change in total arterial circumference relative to a reference cross section ranges from excessive enlargement with an actual increase in lumen to a shrinkage contributing to lumen narrowing. The forces that determine whether an artery shrinks or is able to enlarge as a consequence of atherosclerotic lesions or of post-interventional intimal hyperplasia are unknown but are likely to affect matrix and specifically collagen redistribution. Identifying these forces is of importance because they might be used to promote favorable remodeling. The cellular and humoral triggers of collagen degradation and synthesis, as well as conformation changes of collagen matrices after their deposition, need to be investigated. As with injury-induced intimal hyperplasia and plaque growth in de novo atherosclerosis, injury models may serve as a paradigm for geometric remodeling in atherosclerosis.

The objective of this study was to determine whether basic fibroblast growth factor (bFGF), a known angiogenic factor, can promote new vessel growth when infused within the pericardial space in a model of chronic myocardial ischemia. Intravenous angiotensin II (AII) was infused to induce left ventricular hypertrophy and concomitant ischemia in New Zealand white rabbits. Basic FGF was infused into the intrapericardial space with an osmotic pump. Animals were assigned to one of four groups: group 1 received intrapericardial bFGF and intravenous AII, group 2 received intrapericardial bFGF and intravenous saline solution, group 3 received intrapericardial albumin and intravenous AII, and group 4 received intravenous AII only. Epicardial angiogenesis was graded histologically on a scale of 0 to 2. Animals receiving intravenous administration of AII displayed left ventricular hypertrophy that disproportionately affected the interventricular septum with a wall thickness of 5.62 +/- 1.00 mm versus 3.98 +/- 0.61 mm in the AII group and the saline solution control group, respectively (p0.005). A highly localized angiogenic effect of bFGF was observed. The mean angiogenesis scores were 1.9, 1.4, 1.3, and 0.2 (p0.001) with an angiogenesis score of 2 (marked increase in vascularity) noted in 86%, 40%, 43%, and 0% of hearts in groups 1 through 4, respectively. We conclude that intrapericardial bFGF enhances new epicardial small-vessel growth in a rabbit model; furthermore this effect is enhanced in the presence of left ventricular hypertrophy.

Summary Reocclusion after fibrinolysis is a thrombotic event most likely due to the persistence of the thrombogenic stimuli such as plaque fissures that caused the occlusion in the first place. After angioplasty, more severe vascular wall disruption and elastic recoil are additional mechanisms of early reocclusion. Either spontaneous fissures or angioplastic modifications of the vascular wall initiate a remodeling process that primarily restores and possibly stabilizes and reinforces the wall tissue. The mechanisms which turn this desirable healing process into restenosis include failure of coordination and down-regulation of initiating stimuli and responses, poorly adapted tissue fragments, exposure of additional thrombogenic surfaces, excessive cell growth and synthesis of matrix, and contracture of the newly formed scar tissue, leading to a chronic compromise of the effective lumen.

BACKGROUND In de novo human atherosclerosis, compensatory vessel enlargement limits the effect of intimal plaque formation on lumen narrowing. We hypothesized that arterial remodeling may also play an important role in determining the chronic lumen size after angioplasty and tested this hypothesis using the hypercholesterolemic rabbit iliac artery angioplasty model. METHODS AND RESULTS Morphometric analysis of histological cross-sectional areas of vessels from animals killed immediately after angioplasty (acute group, n = 11) were compared with the same areas from animals killed 4 weeks after the procedure (chronic group, n = 37), when restenosis occurs in this model. The area circumscribed by the internal elastic lamina (IEL) increased by 20% from acute to 4 week follow-up after angioplasty (acute group, 2.36 +/- 0.45 mm2, chronic group, 2.84 +/- 0.89 mm2). Over the same time period, intimal area increased by 0.82 mm2. Despite this increase in intimal area, lumen area decreased by only 0.34 mm2 because of the compensatory enlargement of the IEL area. In the chronic group, polynomial regression analysis revealed a quadratic relation between intimal area and lumen area (R2 = .35, P < .001). A lumen area of 0.45 mm2 (the nadir of the quadratic relation) was used to divide the chronic group into two subgroups: restenotic (n = 21; lumen area, < 0.45 mm2) and nonrestenotic (n = 16; lumen area, > 0.45 mm2). By definition, there was a significant difference in lumen area between the two subgroups (0.15 +/- 0.15 mm2 for restenotic; 0.73 +/- 0.18 mm2 for nonrestenotic). Surprisingly, the intimal areas in the two subgroups were virtually identical (2.41 +/- 0.92 mm2 for restenotic, 2.49 +/- 0.69 mm2 for nonrestenotic, P = NS). The difference in the lumen area between restenotic and nonrestenotic vessels was a result of the significantly greater IEL area in the nonrestenotic subgroup (3.22 +/- 0.83 mm2 for nonrestenotic, 2.56 +/- 0.84 mm2 for restenotic, P < .05). In both restenotic and nonrestenotic vessels, the IEL area increased with increases in intimal area. In the restenotic arteries, the slope of this correlation was < 1, showing inadequate compensatory enlargement for the intimal plaque. In the nonrestenotic vessels, the slope was > 1, limiting the effect of intimal plaque on luminal narrowing. CONCLUSIONS These data indicate that the iliac artery in an atherosclerotic rabbit model compensates for intimal formation after angioplasty by vessel enlargement. Furthermore, the degree of vessel enlargement is more important than intimal area in determining the chronic lumen size.

Atherosclerosis, a chronic systemic disease of the vasculature with an inflammatory component, is the primary cause of cardiovascular morbidity and mortality in industrialized countries. Impairment of vascular endothelial cell function in atherosclerosis and in conditions associated with increased cardiovascular risk are important determinants of disease progression. Reduced endothelium-dependent relaxation in the coronary and systemic circulation due to decreased bioavailability of nitric oxide (NO) and increased release of oxygen-derived free radicals promotes the adhesion of leukocytes, thrombosis, inflammation, cell proliferation, and increases in vascular tone. In addition to decreases in bioactive NO, enhanced production of the 21-amino acid peptide endothelin-1 contributes to the progression of atherosclerosis. This paper discusses mechanisms and therapeutic approaches to improving endothelial pathways in atherosclerosis. Restoration of endothelium-derived NO bioactivity through inhibition of the renin-angiotensin system, the endothelin system, or statin therapy improves vascular function in experimental hypercholesterolemia, hypertension and heart failure. These treatments may also have therapeutic benefit for patients at risk or with overt atherosclerosis, and are likely to reduce vascular and myocardial complications of this disease.

Internal mammary artery specimens from 17 patients were each divided into three separate rings. One ring (control) remained in Krebs solution and the other two were clamped for 30 minutes with either a soft or hard jaw clamp. Isometric tensions were measured in an organ chamber by contracting the rings twice with a thromboxane A2 mimetic, U46619, and relaxing the rings first with the endothelium-dependent agent acetylcholine followed by the endothelium-independent agent sodium nitroprusside. Endothelium-dependent maximal relaxation of the rings was impaired from control after both soft (20% versus 91%; p horac C ardiovasc S urg 1992;104:966-71)

This study was undertaken to study the effects of hyperlipidemia and hypertension on the coronary circulation and on the myocardium of Watanabe heritable hyperlipidemic (WHHL) rabbits. Surgery to induce hypertension by the one-kidney, one-clip technique was performed on the WHHL rabbits at 3 months of age. At 3 and 6 months after surgery, the right and left coronary arteries and the left ventricle and posterior papillary muscle from normotensive and hypertensive animals were assessed. Atherosclerotic involvement was found at the coronary origin in 94% of the arteries evaluated. Lesions were usually confined to the proximal 1-2 mm of the coronary artery. The prevalence of coronary atherosclerosis in the WHHL rabbit was found to be higher than previously reported in rabbits of the same age. Hypertension-induced muscular and vascular changes such as left ventricular hypertrophy, medial thickening of the arteries, and hyaline arteriolosclerosis were found in most of the hypertensive animals. These changes were rarely seen in the normotensive rabbits. Characteristics of ischemia and cell injury such as eosinophilic fibers, fiber vacuolization, and contraction band necrosis were found more often in hypertensive than in normotensive WHHL rabbits. Confluent areas of severe necrosis indicative of myocardial infarction were not found; myocardial damage was diffuse and involved individual cells and small microscopic areas. This model may be valuable in further studies of coronary artery disease and myocardial injury that result from the combination of hypercholesterolemia and hypertension.

This is an investigation of the relationship between graft preparation techniques and the subsequent fate of vein grafts. Vein grafts intentionally injured by warm saline storage demonstrated endothelial and smooth muscle cell damage. In the acute postimplantation period, platelet adhesion/activation and white cell infiltration were present. By 7 days the endothelium had “healed,” but the underlying smooth muscle cells had modulated and were of the synthetic phenotype. This persisted at 30 days, but by 60 days the graft wall remodeled with smooth muscle cells that were of the contractile phenotype, with an organized extracellular matrix. None of these injurious responses were noted in optimally prepared papaverine-treated vein grafts. Optimal preparation of vein grafts is effective in minimizing endothelial and smooth muscle cell injury before and after arterial reconstruction. Prevention of vein graft injury during harvesting prevents the morphologic changes characteristic of the “arterialization response.” (J T horac C ardiovasc S urg 1992;103:671-7)

Fibulin-1 is a fibrinogen-binding blood protein and a component of many extracellular matrices (ECM) including those of blood vessels. In this study, the deposition patterns of fibulin-1 and fibrinogen were examined in human coronary artery atherosclerotic lesions excised by atherectomy from 20 patients. Fibulin-1 deposition was found to be closely overlapping with fibrinogen located within the atherosclerotic lesions and in regions containing fresh thrombi. Pronounced intracellular fibulin-1 immunostaining was apparent in lesion areas rich in macrophages and foam cells, although THP-1 macrophages and foam cells were found not to express fibulin-1. Strong ECM deposition of fibulin-1 was observed in acellular atheromatous and myxomatous regions. By contrast, fibulin-1 was present at relatively low levels in the ECM associated with smooth muscle cells within and outside of lesions and was not detected in sclerotic regions. These results reveal the pattern of fibulin-1 within human atherosclerotic lesions and highlight the potential for fibulin-1, perhaps derived from the blood and acting in conjunction with fibrinogen, to play a role in the etiology and cardiovascular disease progression, particularly with respect to thrombotic aspects of atherosclerosis.

Laser thermal recanalization has been used clinically as an adjunct to balloon angioplasty in the treatment of peripheral arteriosclerotic disease, with improved initial success rates in total peripheral occlusions and greater 1 yr vessel patency suggested, as compared to balloon angioplasty alone. However, the morphological effects of laser-assisted balloon angioplasty are unknown. Therefore the goals of the present study were to evaluate 1) the angiographic and nistologic effects of laser thermal recanalization followed by balloon angioplasty and 2) the hypothesis that balloon-catheter-induced neointimal fracture could be sealed by subsequent laser thermal angioplasty in an experimental rabbit iliac artery atherosclerotic model. In Group 1(7 vessels), a 1.5 mm metal capped argon laser fiberoptic was introduced via femoral arteriotomy and 10 W of thermal power was applied to the iliac artery stenosis for 5 sec while maintaining constant back-and-forth motion. Thereafter, balloon angioplasty was performed in the same vessel segment with a 2.5 mm balloon catheter inflated 3 times at 5 atm for 30 sec each. Mean angiographic luminal diameter increased from 1.1 mm to 2.0 mm after both procedures, and mean final post balloon dissection grade was 0.6 on a scale of 0,1 +, and 2 +. Perforation occurred once with the laser probe and once with the balloon catheter. Histologic examination of these vessels was characterized by irregular thermal erosions with minimal reactive thrombosis. In Group 2 (10 vessels), the sequence was reversed, with laser thermal angioplasty following balloon dilation. Mean angiographic luminal diameter improved from 1.2 mm to 1.8 mm after both procedures. The mean post laser thermal angioplasty dissection grade was 1.3, which was twice that of Group 1. Perforation occurred once with the balloon catheter and twice with the laser probe. In only 1 of the 10 vessels was there histologic evidence suggestive of neointimal sealing. In conclusion, laser thermal recanalization prior to balloon angioplasty appears to decrease the degree of angiographic dissection. Histologically, the thermal effect may be eccentric, and thrombosis appears to be limited. However, laser thermal sealing was not found to be feasible with the current 1.5 mm metal-capped fiberoptic after dilation with a 2.5 mm balloon catheter. This is possibly due to inadequate contact of the probe with the vessel wall. There may also be anincreased tendency towards laser probe perforation following the fracture and dissection which results from balloon dilation.

11029 Background: It has been well documented that enumeration of Circulating Tumor Cells (CTCs) isolated from the peripheral blood of breast cancer patients can be used as a prognostic indicator o...

Background Chimeric proteins may be used to direct cell-specific activity. Heparin-binding growth-associated molecule (HBGAM) binds to cell receptors that are relatively more robust on endothelial cells, and it may confer endothelial cell selectivity to potent angiogens such as fibroblast growth factor-1 (FGF-1). Methods By ligating fibroblast growth factor or its potent mutant, S130K, to HBGAM, we tested their effect on re-endothelialization after angioplasty injury by using a canine model. Results Both HBGAM/S130K- and HBGAM/FGF-1–treated arteries had increased neointimal mitotic index and re-endothelialization rates at 30 days compared with control arteries without inducing a significant increase in the neointimal thickness or the ratio of neointimal to medial thickness between treatment and control groups. Conclusion HBGAM/S130K and HBGAM/FGF-1 facilitates endothelial healing without myointimal thickening after canine carotid artery balloon angioplasty injury. Application of these growth factors in fibrin glue may improve endothelialization clinically after angioplasty or endarterectomy.

Atherosclerotic vascular disease Atherosclerosis: a chronic inflammatory condition Atherosclerosis, a chronic systemic disease of the vasculature with an inflammatory component, remains the major cause of disease and death in industrialized countries [1–3]. Early atheromatous vascular changes are already present during fetal life and maternal plasma cholesterol levels determine the severity of fatty streak formation in the aorta of the fetus [4,5]. Intimal accumulation of low-density lipoproteins (LDLs) precedes monocyte recruitment [4], thus a direct inflammatory effect of native, non-oxidized LDLs is likely to be involved in vascular lesion formation [6]. Fatty streaks persist in adolescents [1] and form the basis for a chronic process developing over decades with progressive atheroma formation. Loss of organ function due to infarction is a frequent consequence of advanced disease, which in most cases is due to rupture of the fibrous cap covering the atheromatous plaque [1,3]. The inflammatory mechanisms underlying plaque development and rupture are regulated by a number of conditions as indicated by the multiple risk factors involved in atherogenesis [1]. As discussed in the next paragraph, inflammatory changes in the endothelium play a crucial role for the onset and continuation of the disease.

Septic shock is believed to be a consequence of excessive stimulation of the immune system by bacterial toxins that results in systemic overproduction of proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), IL-1, and IL-6. Various studies have shown that TNF-alpha, a major mediator of septic shock, induces tissue injury, loss of blood pressure, organ failure, and ultimately death. Administration of the opioid antagonist naloxone has been reported to reverse opiate-mediated hypotension, promote organ perfusion and increase patient survival. In this study, we examined the mechanism by which the opioid receptor antagonist, naltrexone, modulates the septic shock response in BALB/c mice after injection with lipopolysaccharide (LPS) or staphylococcal enterotoxin B (SEB) in combination with d-galactosamine (d-gal), or with agonistic anti-Fas antibody (Jo2) alone. Each of these treatments induced rapid-onset, acute shock, and ultimately mortality (6-9h after injection), although different mechanisms are involved. Administration of the opioid antagonist naltrexone protected mice from shock induced by LPS+d-gal, but not SEB+d-gal or Jo2 antibody, a protective effect that was reversed by morphine. Naltrexone significantly inhibited the production of TNF-alpha induced by LPS, but not SEB in vivo. When bone marrow-derived, splenic or peritoneal macrophages were treated with LPS in vitro, administration of naltrexone had no direct effect on TNF-alpha production. These results suggest that naltrexone is capable of preventing LPS-induced septic shock mortality by indirect inhibition of TNF-alpha production in vivo.

The transition of coronary lesions from the stable to unstable state is the pathophysiologic mechanism underlying myocardial infarction and unstable angina pectoris. Angiographic, angioscopic and postmortem pathologic studies suggest that this transition is mainly due to atherosclerotic plaque fissuring and associated thrombus formation.‘.2 The present study examines the tiistopathologic characteristics of the “culprit lesion” obtained during directional coronary atherectomy of patients with acute coronary syndromes. Directional atherectomy provides a unique opportunity for studying the composition of unstable lesions in living symptomatic patients. Case histories of consecutive patients referred to the University of Michigan Medical Center for directional coronary atherectomy after May I, 1989 were analyzed. All patients selected for inclusion in this study had angina, objective evidence of myocardial ischemia and cineangiograms showing 21 lesion with >50% diameter stenosis of an epicardial coronary artery. The unstable group comprised patients who had experienced ischemic pain at rest accompanied by transient ST-T changes on the electrocardiogram, or acute myocardial infarction during the 2-week period preceding directional atherectomy. The stable group comprised patients who had not had ischemic pain at rest, progressive angina, recent-onset angina or acute myocardial infarction during the 3-month period preceding directional atherectornv. Directional atherectorny was petformed as described previously.3 The atherectomy device (Devices

Backgroud: Neointimal hyperplasia following percutaneous transluminal coronary angioplasty (PTCA) is one of the major components of the process of restenosis. We evaluated the long-term impact of local delivery of c-myc neutrally charged antisense oligonucleotides (Resten-NG) upon neointimal formation following PTCA in a rabbit model. Methods: PTCA was performed in the iliac arteries of 10 New Zealand white rabbits at 8 atm for 30 s, three times. An infusion of 500 μg Resten-NG ( n =6) or saline ( n =4) was delivered to the site at 2 atm via the outer balloon pores of the transport™ catheter over 2 min. The diet was supplemented with 0.25% cholesterol for 10 days before and 6 months following PTCA. Results: After 6 months, animals were sacrificed and vessels were fixed in formalin, processed and stained with hematoxylin, eosin, and movat. Histological analysis revealed complete vascular healing in both groups of animals. Planimetry showed that intimal areas were 1.71±0.25 and 0.65±0.36 mm 2 in the control and antisense delivery groups, respectively ( P Conclusion: We conclude that local delivery of Resten-NG significantly inhibited neointimal thickening following PTCA in a rabbit for up to 6 months.

e22107 Background: With the advent of next-generation sequencing techniques, tumor mutations that guide therapeutic decisions can be identified on a large scale. The ability to accurately detect th...

1. Arapov AD, Vishnerskii AA Jr, Abdullaev FZ, Korchagin VA, Mirtskhulava KA, Sorgin ME. A preliminary report on laser application in cardiosurgery. Eksp Khir Anesteziol 1914;4:10-12. 2. Macruz R, Martins JRM, Tupinnamba HS, Lopes EA, Varbas H, Penna AF, Carvalho VB, Armelin E, Decourt LV. Possibilidades terapeuticas do raio laser em ateromas. Arq Bras Cardiol 1980;34:9-12. 3. Riemenschneider TA, Lee G, Ikeda RM, Bommer WJ, Stobbe D, Ogata C, Rebeck K, Reis RL, Mason DT. Laser irradiation of congenital heart disease: potential for palliation and correction of intracardiac and intravascular defects. Am Heart J 1983;106:1389-1393. 4. Ginsburg R, Wexler L, Mitchell RS, Proffit D. Percutaneous transluminal laser angioplasty for treatment of peripheral vascular disease. Clinical experience with 16 patients. Radiology 1985;156:619-624. 8. Sanborn TA, Cumberland DC, Welsh CL, Greenfield AJ, Guben JK. Percutaneous laser thermal angioplasty: initial results and 1 year follow-up in 129 femoropopliteal lesions. Radiology 1988;168:121-125. 6. Kirklin JW, Barratt-Boyes BG. Cardiac surgery. New York: John Wiley, 1986:821-856. 7. Kirklin JW, Blackstone EH, Shimaznki Y, Maehara T, Pacific0 AD, Kirklin JK, Bargeron LM Jr. Survival, functional status, and reoperations after repair of tetralogy of Fallot with pulmonary atresia. J The-m Cardiovasc Surg 1988; 96:102-116.

BACKGROUND: Direct myocardial revascularization (DMR) is being explored to improve symptoms in patients with refractory ischemic coronary syndromes. This study assessed the safety and feasibility of percutaneous DMR using the Biosense non-fluoroscopic navigation system (incorporating the holmium : yttrium aluminium garnet laser) in pig hearts. METHODS AND RESULTS: Twenty pigs underwent left ventricular mapping using the Biosense system, followed by percutaneous DMR with a holmium : yttrium aluminium garnet laser at 2 J x 1 pulse, and were sacrificed acutely (n = 5), at 24 h (n = 5), and at 3 weeks (n = 10) after the DMR procedure. The hearts were examined grossly and microscopically. Serial creatine kinase-MB level was measured up to 24 h. There were no procedural complications. Animals received 13 +/- 2 channels in 19 +/- 7 min. The catheter was able to reach all regions, including the septum. There was no increase in creatine kinase-MB level up to 24 h. One animal died within an hour of the procedure. There was one sealed perforation into the subepicardial fat as a result of same site laser activation. Histologic evaluation in the acute and 24 h groups revealed laser channels which were 3.6 +/- 2.2 mm long, 1.5 +/- 0.7 mm wide, with an entry angle of 73 +/- 12 degrees. Channels were filled with platelet thrombi acutely and were surrounded by well-defined rims of thermal coagulation and an 'impact zone' of viable myocardium; at 3 weeks, no channels remained patent and they had been replaced by well-healed granulation tissue. CONCLUSIONS: It is feasible and safe to perform percutaneous DMR with the Biosense system and the channels created with the chosen laser parameters are rapidly sealed with platelet thrombi and at 3 weeks are replaced by well-healed granulation tissue.

The atherosclerotic carotid artery is easily accessible for non-invasive duplex investigation. The aim of the present post mortem study was to examine whether plaque accumulation and luminal stenosis in the common carotid artery is representative for atherosclerotic plaque accumulation and luminal stenosis in other peripheral arteries. A total of 3765 cross-sections were obtained at regular intervals from 240 arteries (24 individuals). Five types of peripheral arteries were investigated: common carotid, femoral, common iliac, external iliac and renal arteries. In each cross-section, the lumen area, vessel area, plaque area and maximal plaque thickness was measured. For each location, the percentage luminal stenosis and relative plaque area was calculated. Relative plaque area was defined as the percentage of the vessel area which was occupied by plaque. Weak correlations (r=0.41-0.59) were observed between percentage relative plaque area or maximal plaque thickness in the common carotid artery and percentage relative plaque area in other peripheral arteries. Neither plaque accumulation nor luminal stenosis in the common carotid artery correlated with the percentage luminal stenosis in other peripheral arteries (P > 0.05). We conclude that plaque area in the common carotid artery is weakly correlated with plaque area and not correlated with luminal stenosis in other peripheral arteries.

Purpose: Fogarty balloon denudation in experimental animals often serves as a model for percutaneous transluminal coronary angioplasty (PTCA). We compared the healing response of the arterial wall with the use of Fogarty and PTCA balloon dilation. Methods: Carotid arteries of rabbits were injured with a 2F Fogarty (n = 9) or a 3 mm PTCA balloon (n = 6). At 1 day endothelial cell removal was qualitatively evaluated in Fogarty balloon lesions and in PTCA balloon lesions with a modified "en face" silver nitrate staining. Medial necrosis was morphometrically determined as percentage medial area. After 21 days endothelial cell coverage was assessed in the center of the lesion with an antibody to CD31 and intimal proliferation with an antibody to the nuclear antigen Ki-67. Intimal hyperplasia area was measured with morphometry. Acute lumen gain directly after Fogarty balloon dilation and PTCA balloon dilation was determined by serial angiography. All data are means ± SEM. Results: At 21 days intimal hyperplasia area was higher in the Fogarty balloon lesions than in the PTCA balloon lesions. Intimal hyperplasia area was 0.19 ± 0.02 mm 2 and 0.03 ± 0.01 mm 2 , respectively. Immediately after injury the acute gain in luminal diameter did not differ between Fogarty and PTCA balloon dilation (0.37 ± 0.03 mm and 0.38 ± 0.05 mm, respectively). At 1 day after injury endothelial cell removal was complete in all segments. Medial necrosis caused by Fogarty (67% ± 7%) and PTCA balloon dilation (74% ± 9%) did not differ. At 21 days endothelial cell coverage was almost complete both in the Fogarty balloon lesions and in the PTCA balloon lesions. Intimal proliferation was also higher in the Fogarty balloon lesions than in the PTCA balloon lesions. Conclusion: Despite comparable endothelial cell abrasion and medial necrosis, Fogarty balloon injury elicited significantly augmented intimal hyperplasia compared with PTCA balloon dilation. (J Vasc Surg 1996;24:843-50.)

To determine whether metastatic calcification during neointima formation can result in neointimal calcification that simulates advanced human atherosclerosis, 32 giant Flemish rabbits (weight 5.5 +/- 0.6 kg) underwent overstretch balloon injury of bilateral iliac arteries and received diet therapy for 8 weeks: high cholesterol (2%) and low calcium-vitamin D2 regimen (250 mg of calcium carbonate orally 5 times weekly and 50,000 U of calciferol intramuscularly 3 times weekly; group 1; n = 5); low cholesterol (0.5%) and high calcium-vitamin D2 regimen (500 mg of calcium carbonate orally 5 times weekly and 100,000 U of calciferol intramuscularly three times weekly; group 2; n = 19); or 0% cholesterol and high calcium-vitamin D2 regimen (group 3; n = 8). The incidence of vascular calcification was highest (71.4%) in group 2. Eighty-one percent of calcification was medial. Residual strain measurements of 7 thoracic aortas from group 2 compared to normal thoracic aortas from 8 control rabbits showed that residual strain was significantly increased in the calcified atherosclerotic aortas (12.3% vs 5.2%; p = 0.001). We conclude that diet-induced hypercalcemia predominantly affects the media despite the presence of concomitant neointima formation from balloon artery injury with or without hypercholesterolemia and increases the residual strain more than twofold compared to normal thoracic aortas.

Temporary clamping of the internal mammary artery pedicle is required for visualization during coronary artery bypass grafting. A nylon fibril jaw surface has been developed for these clamps that exerts pressure only at discrete sites on the pedicle surface. The effect of this new jaw surface on endothelial cell function and integrity after compression is investigated in this study.Internal mammary artery specimens from 10 patients each were divided into three separate rings, and two of these rings were clamped for 30 minutes with either a smooth or fibrous jaw clamp. Isometric tensions were measured in organ chambers after contraction by relaxing the rings with the endothelium-dependent agent acetylcholine followed by the endothelium-independent agent sodium nitroprusside. The intimal surfaces of similar rings were silver stained to assess the percentage of intact endothelium.Endothelium-dependent relaxation was spared after fibrous jaw clamping (75% versus 89%) but significantly impaired after smooth jaw clamping (25% versus 89%; p0.001). Endothelium-independent relaxation was unaffected by either intervention. The percentage of remaining intact endothelium upon silver staining was significantly less after smooth than after fibrous jaw clamping (24% versus 48%; p0.01).Foam silicone with nylon fibrils on the jaw surface of internal mammary artery clamps preserves endothelial cell function and integrity. The remaining undamaged cells also may facilitate the subsequent regeneration of a confluent endothelial cell layer.

Conventional angioplasty of aorto-ostial lesions (≤3 mm from aorta) is frequently associated with suboptimal results, high procedural complications, and increased restenosis rate compared to non-ostial lesions. To gain insight into the differences between aorto-ostial and non-ostial lesions, directional atherectomy (DCA) samples of de novo native aorto-ostial lesions from 32 patients (64 ± 11 years; 22 men) were compared to randomly selected DCA samples of de novo native non-ostial lesions from 34 patients (61 ± 11 years; 23 men). Results (1) The amount of tissue removed was similar between the two groups (6.4 ± 3.6 μm 2 vs. 6.2 ± 3.8 μm 2 ). with predominantly fibrosclerotic plaque (59% vs. 68%): (2) The aorto-ostial group had significantly more areas of high cellularity vs. non-ostial group (0.73 ± 0.74 μm 2 vs. 0.41 ± 0.49 μm 2 ; p l 0.05): (3) The aorto-ostial group tended to contain more thrombus (0.61 ± 0.79 μm 2 vs. 0.29 ± 0.35 μm 2 ; p l 0.08); and (4) the aorto-ostial DCA samples more frequently had adventitial tissue (0.1 0 ± 0.14 μm 2 vs. 0.04 ± 0.06 μm 2 ; p = 0.07). We conclude that: (1) The aorto-ostiallesions seem to experience greater spontaneous trauma and stimulus for proliferation, as evidenced by the more abundant reactive cellular component. This histologic confirmation of the known rheologic effect on aorto-ostial regions may explain the increased restenosis rate observed with these lesions.: (2) The aorto-ostiallesions are more unstable, with a trend for more thrombotic component. This may explain the high procedural complications during angioplasty of the aorto-ostiallesions.: and (3) DCA specimens from the aortoostial lesions tended to have greater amount of adventitia, another potential source for procedural complication and increased restenosis. These findings suggest that there are biologic explanations for observed suboptimal acute and chronic results after angioplasty of aorto-ostial lesions, and further suggest a need for an improved strategy, such as minimization of the aorto-ostial turbulent flow possibly with stenting combined with local pharmacologic treatment.

Enoxaparin (EN), when systemically administered, has been shown to reduce restenosis in preclinical studies. Previously, we demonstrated that 3 H-EN locally delivered via channeled balloon (CB), a dual-purpose local delivery catheter capable of simultaneous angioplasty, was retained intramurally for at least 24 hours, To determine whether locally delivered EN can reduce restenosis by inhibiting smooth muscle cell proliferation, 3 groups of rabbits underwent balloon injury of bilateral iliac arteries with CB (balloon/artery = 1.1), followed by assigned treatment [4 control rabbits (CO) receiving local saline in 8 arteries, 4 local EN rabbits (LOC) receiving one-time local EN @ 10 mg/kg at the time of angioplasty in 8 arteries, and 5 combined treatment rabbits (COM) receiving one-time local EN @ 10 mg/kg in 10 arteries and systemic EN @ 10 mg/kg s.c. daily for one week). One week later, the animals were euthanized and the iliac arteries were perfusion fixed for proliferating cell nuclear antigen (PCNA) staining. Anti-factor Xa activity (A-Xa) as a measure of successful EN delivery was measured at baseline (0.024 ± 0.02 units/ml), 1 hour and 24 hours after the procedure. PCNA (7 days) † A-Xa (units/ml) Media Intima 1 hour 24 hours CO 4.04 ± 2.6 25.5 ± 8.4 0.02 ± 0.03 0.06 ± 0.07 LOC 4.8 ± 4.1 16.9 ± 11.9 ††† 1.25 ± 0.27 * 0.12 ± 0.05 COM 1.6 ± 2.2 †† 7.3 ± 9.2 †††† 1.43 ± 0.12 * 0.20 ± 0.10 ** † (+) PCNA nucle/μm2 †† p = 0.06 vs. CO ††† p = 0.09 vs. CO †††† p = 0.001 vs CO * p g 0.005 vs. CO ** p g 0.05 vs. CO We conclude that (1) Locally delivered enoxaparin tended to reduce smooth muscle cell proliferation, and significantly inhibited smooth muscle cell proliferation with concomitant systemic enoxaparin treatment, as assessed by PCNA staining; (2) Supporting local enoxaparin effect with systemic treatment at critical time point for smooth muscle cell proliferation seems necessary: and (3) anti-Factor Xa activity levels suggest sustained (up to 24 hours) enoxaparin activity only with combined local and systemic treatment.

The effects of trandolapril (0.25 mg/kg body wt per 48 hours) on aortic atherosclerosis were examined in the Watanabe heritable hyperlipidemic rabbit treated from 3 to 12 months of age. Trandolapril caused a significant decrease in atherosclerotic involvement of the intimal surface of total aorta from 56.3 +/- 5.0% in control Watanabe rabbits to 35.0 +/- 4.1% with treatment (p less than 0.01). The largest reductions were observed in descending thoracic aorta where 21.8 +/- 5.7% of intimal surface was involved in the trandolapril-treated animals versus 54.4 +/- 7.7% in the control group (p less than 0.01). Significant decreases also occurred in ascending aorta/arch and abdominal aortic segments. Cholesterol content of descending thoracic aorta was also significantly reduced in the trandolapril-treated rabbits. The atherosclerotic plaques in aorta from trandolapril-treated rabbits appeared to contain less foam cells and relatively greater amounts of connective tissue than those from control animals. These studies indicate that trandolapril inhibits aortic atherosclerosis in the Watanabe heritable hyperlipidemic rabbit. The similarity in results between the current study and that using captopril suggests that the antiatherosclerotic action of trandolapril and captopril represents a class effect related to angiotensin converting enzyme inhibition.

Antiplatelet therapy is routinely used in balloon angioplasty. Yet recent clinical trials have not shown these agents to reduce the incidence of restenosis. As this might be due to inadequate antiplatelet effect, this study was designed to evaluate the effectiveness of antiplatelet therapy in reducing platelet accumulation immediately after angioplasty. Sixty-six atherosclerotic rabbits underwent angioplasty of a focal (50-99%) iliac stenosis after pretreatment with an antiplatelet drug. The animals were randomly given aspirin (10 mg/kg orally) (n = 10), aspirin (10 mg/kg intravenously) (n = 7), aspirin (10 mg/kg per os) plus dipyridamole (25 mg orally) (n = 8), a thromboxane synthetase inhibitor (GS13080, 1 mg/kg/h intravenously) (n = 9) or heparin (500 U/kg intravenously) (n = 9). Platelet accumulation, determined by 51Cr-labeled platelet counts 30 min after angioplasty disclosed a significant reduction from control (44.1 +/- 51.2 platelets/cm x 10(6)) with intravenous aspirin (3.3 +/- 1.9; p less than 0.007) and the thromboxane synthetase inhibitor CGS13080 (15.1 +/- 16.6, p less than 0.04). Aspirin plus dipyridamole reduced platelet accumulation as well (10.4 +/- 9.8, p = 0.076), while oral aspirin (109.5 +/- 240) and heparin (34.7 +/- 35.5) were ineffective. The results of this study demonstrate that pretreatment with antiplatelet agents can reduce platelet accumulation significantly after experimental angioplasty. However, the wide variability in effectiveness particularly with oral aspirin may have important clinical implications. Further investigation into more effective antiplatelet therapy may help to reduce the incidence of abrupt vessel closure and restenosis.

Directional coronary atherectomy can cause ectasia (final area stenosis less than 0%), presumably due to an excision deeper than the angiographically "normal" arterial lumen. In a multicenter series in which quantitative coronary arteriography was performed after directional atherectomy in 382 lesions (372 patients), ectasia after atherectomy occurred in 50 (13%) lesions. By univariate analysis, ectasia was seen more often within the circumflex coronary artery (p = 0.008), in complex, probably thrombus-containing lesions (p = 0.015), and with higher device:artery ratios (p less than 0.001). Ectasia occurred less often in lesions within the right coronary artery (p = 0.008). Histologic analysis demonstrated adventitia or media, or both, in all patients with angiographic ectasia. Repeat angiography was performed in 188 of 271 eligible patients (69%) 6.1 +/- 2.4 months after atherectomy. Restenosis, defined as a follow-up area stenosis greater than or equal to 75%, was present in 50% of patients without procedural ectasia and in 70% of patients with marked ectasia (residual area stenosis less than -20%; p = 0.12). It is concluded that excision beyond the normal arterial lumen may occur after directional coronary atherectomy, related, in part, to angiographic and procedural features noted at the time of atherectomy. Restenosis tends to occur more often in patients with marked ectasia after coronary atherectomy.

Smooth muscle cell proliferation is central to the process of restenosis. Attempts to inhibit the events leading to this proliferation have met with little success. In addition to its known antithrombotic effects, heparin also has inhibitory effects on smooth muscle cell proliferation. These effects appear to be unrelated to its anticoagulant properties and are retained in low molecular weight heparin derivatives. Although the use of heparin for as long as 18 to 24 h after coronary angioplasty in humans has not prevented restenosis, longer treatment periods have not been assessed.This study examines the effect of treatment with a low molecular weight heparin (enoxaparin) in a hypercholesterolemic rabbit iliac artery model. Control rabbits had a mean iliac artery diameter of 0.70 ± 0.06 mm, which increased to 1.73 ± 0.09 mm after balloon angioplasty. At follow-up angiography 4 weeks later, the mean vessel diameter was 0.56 ± 0.12 mm. Animals treated with low dose enoxaparin (1 mg/kg per day) for 4 weeks and high dose enoxaparin (10 mg/kg per day) for either 2 or 4 weeks had similar mean luminal diameters before and immediately after angioplasty. At follow-up angiography, the mean luminal diameter was 0.82 ± 0.17 mm for low dose enoxaparin, 1.04 ± 0.20 mm for 2 week high dose enoxaparin (p = 0.03 versus control) and 1.19 ± 0.09 mm for 4 week high dose enoxaparin (p = 0.001 versus control).When defined as loss of 50% of the initial gain achieved with angioplasty, restenosis was found in all control vessels. In the 2 week high dose enoxaparin group, only two of nine vessels had restenosis and in the 4 week high dose group, three of nine vessels had restenosis (p = 0.001 versus control). These results show that antiproliferative agents such as low molecular weight heparin can inhibit restenosis in animal models and suggest that they may be useful in humans.

Restenosis, the major limitation of balloon angioplasty, is the result of intimai hyperplasia after the procedure. Lovastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) inhibitor, may influence intimai hyperplasia by lowering serum cholesterol and by blocking deoxyribonucleic acid (DNA) synthesis. To determine whether lovastatin reduces intimai hyperplasia, a prospective, randomized blinded study was performed in 60 atherosclerotic New Zealand White male rabbits. Atherosclerosis was produced by air desiccation injury followed by a 28 day diet of 2% cholesterol and 6% peanut oil that was terminated before balloon angioplasty was performed. Angioplasty could not be performed in 14 rabbits with bilateral femoral artery occlusion, and in one rabbit the procedure was a technical failure.Forty-five rabbits underwent balloon angioplasty performed with use of a 2.5-mm balloon inflated to 10 atm for three l min dilations at 1 min intervals. Seven rabbits died during the procedure. Thirty-eight rabbits were randomized to either a lovastatin group (6 mg/kg body weight per day) or a control group. Angioplasty was performed on all patent vessels (n = 54); the procedure was bilateral in 16 rabbits and unilateral in 22. Fifteen lovastatin-treated and 15 control rabbits survived 39 days after angioplasty and were then killed. Angiograms, obtained before and 10 nin and 39 days after balloon angioplasty, were read with use of electronic calipers by two observers who had no knowledge of treatment data. After the rabbits were killed, vessels were pressure perfused using a standardized protocol to maintain in vivo dimensions for minded quantitative histologic analysis.After balloon angioplasty, total cholesterol decreased 36 ± 13% (mean ± SEM) in the lovastatin group (p < 0.05) and 26 ± 15% in the control group (p < 0.05, one-sided ttest). The percent decrease in angiographic luminal diameter from 10 min to 34 days after angioplasty was less in the lovastatin group (n = 22) than in the control group (n = 23) (reader 1:13 ± 11% versus 47 ± 8%, p < 0.05; reader 2:17 ± 8% versus 47 ± 8%, p < 0.01). Intimal thickness was 0.16 ± 0.02 mm in the lovastatin group and 0.30 ± 0.04 mm in the control group (p < 0.01). Thus, lovastatin reduced intimal hyperplasia after balloon angioplasty of the femoral artery in the hypercholesterolemic atherosclerotic rabbit. Its effect in patients undergoing coronary angioplasty should be evaluated.

Since the last workshop on the evolution of the atherosclerotic plaque in 1963, progress in both basic and clinical research has opened several new and promising ways of preventing or delaying the development of atherosclerotic lesions. Impressive advances have also been made in our ability to restore blood flow in vessels where a fully developed, complicated plaque has already caused a significant narrowing or occlusion of the lumen. At this stage, two options are available for intervention directly at the affected vessel segment: a) to bypass the lesion with a graft (tissue or biomaterials), or b) to penetrate or disrupt the lesion by catheter, endarteriectomy, angioplasty, lasers, or by means of cutting instruments. While these techniques have succeeded in immediate re-establishment of channels for blood flow, they have also induced various degrees of vascular trauma, ranging from endothelial denudation to total arterial wall necrosis.

Changes in endothelial permeability and the transport of macromolecules may be important in the initiation and/or progression of atherosclerosis. We have previously shown, with a carotid artery preparation isolated in situ with intact adventitia, that long-term cholesterol feeding in rabbits will result in a seven- to tenfold increase in 125 I albumin transport across the artery into the systemic circulation. The current studies were undertaken to determine whether this abnormality of enhanced permeability could be reversed by cessation of cholesterol feeding and correction of the hyperlipidemia. Two groups of rabbits were fed either a standard Rabbit Chow or a diet containing 1.5% cholesterol and 5.2% corn oil for 12 to 15 weeks. Another group of rabbits was given cholesterol for 12 to 15 weeks with change to standard rabbit chow for an additional 22 to 24 weeks after which albumin transport studies were then performed. Mean plasma cholesterol level after 12 to 15 weeks of cholesterol feeding was 2052 ± 395 mg/dl. After the animals were withdrawn from the cholesterol diet for 22 to 24 weeks, the mean plasma cholesterol level decreased to 80 ± 21 mg/dl. The mean plasma cholesterol value in chow-fed animals was 39 ± 6 mg/dl. Perfusion studies were done with 125 I-labeled albumin and plasma radioactivity served as a measure of transport across the carotid artery. The average level of albumin transport across the artery into venous blood in the cholesterol-fed animals (13,911 dpm/ml of plasma) was significantly greater than that of control animals (2049 dpm/ml of plasma). The sevenfold increase in albumin transport induced by hypercholesterolemia was significantly reduced to near control levels by cessation of cholesterol feeding (3750 dpm/ml of plasma). This occurred despite the absence of complete regression of intimal plaques by tissue lipid analysis or microscopic examination of the carotid arteries. These findings suggest that the enhanced permeability to albumin in the carotid artery induced by cholesterol feeding is reversed by cessation of a high cholesterol diet despite the persistence of intimal lesions. We can only speculate what role this correction of enhanced permeability plays in regression of atherosclerotic lesions. The results provide further evidence that cholesterol feeding induces functional changes in the arterial endothelium, which increases vascular permeability to albumin. (J VASC SURG 1987;5:336-41.)

In an effort to accelerate development of a biologic lining on the fibrillar surface of a left ventricular assist pump, the blood-contacting interface was covered with bovine fetal fibroblasts immediately prior to implantation into the animal. Selection of these syngeneic cells was based on their demonstrated prolificacy and abundant collagen production. Comparative studies, carried out in 17 Holstein calves, indicated that an adherent, thin, collagenous lining developed on the fibroblast-seeded polyurethane pump chamber in nine animals. Similar implantations of eight non-cell-seeded (control) devices resulted in formation of a predominantly acellular, fibrinous membrane, varying in thickness from 1 to 8 mm. Pump chamber compliance was significantly reduced when the histologic surface exceeded 3 mm in thickness, resulting in impaired filling and an inadequate stroke volume. The use of 14C-thymidine-labeled fibroblasts permitted later identification of the donor cells in the collagenous linings by radioautography. Serial immunologic studies undertaken to detect evidence of rejection in recipient Holstein calves were negative.

Investigations to develop an implantable assist pump for prolonged circulatory support have been impeded by accumulation of friable thrombus on the prosthetic interface, with subsequent embolization. To circumvent this problem, the textured, fibril surface of a polyurethane pump chamber (mat thickness 430 microns) was inoculated with cultured bovine fetal fibroblasts (labelled with thymidine-14C) prior to animal implantation. The pneumatically actuated device (stroke volume 75 ml), maintained a pulsatile blood flow throughout each study. In 20 calf experiments, extending up to 335 days, 30 X 10(6) fibroblasts (in 50 ml media) derived from a single Holstein fetus were distributed on the urethane surface (360 +/- 50 cells/mm2) by rotation of a sealed device for three hours (12 revolutions/hour). Following connection to the circulation, cell washout was minimal. Resultant biologic linings, examined after animal sacrifice, were densely adherent to the underlying polymer matrix, and varied in thickness from 250 micron-1.5 mm. Microscopically, fibroblasts were identified from the surface to base, accompanied by numerous collagen bundles and abundant ground substance. Amino acid analysis in 10/20 pumps implanted for 31--335 days, revealed 50 +/- 5 Hydroxyproline residues/1000 residues (50% collagen) and scant elastin. Donor fibroblasts were identified by radioautography and karyotyping. Lack of immunologic response in 12 Hereford pump recipients as confirmed by serial fibroblast cytotoxicity assays. In conclusion, an induced collagenous-blood interface permitted prolonged mechanical circulatory support in animals without thromboembolic complications.

The angiographic and histologic consequences of laser thermal angioplasty were examined and compared with those of conventional balloon angioplasty in an atherosclerotic rabbit iliac artery preparation immediately and 4 weeks after the procedure. Nineteen vessels in 13 rabbits underwent either laser thermal or balloon angioplasty in random order. Laser thermal angioplasty was performed in a total of nine vessels with either a 1.5 or 2.0 mm laser-heated metallic-capped fiber by delivery of 6 or 8 W, respectively, of argon laser energy for 5 sec duration during continuous advancement through the stenosis. Balloon angioplasty was performed in a total of 10 stenotic lesions with a 2.5 mm balloon catheter. The immediate enlargement of the angiographic luminal diameters was similar for both procedures: from 1.0 +/- 0.2 to 1.9 +/- 0.2 mm for laser thermal angioplasty vs 1.0 +/- 0.1 to 2.0 +/- 0.2 mm for balloon angioplasty. However, 4 weeks later the vessels treated with laser thermal angioplasty had less restenosis, defined as a 20% or greater reduction in luminal diameter (two of nine vessels [22%] vs 10 of 10 vessels [100%]; p less than .001), and a significantly larger mean luminal diameter (1.6 +/- 0.5 vs 1.0 +/- 0.4 mm) than those treated with conventional balloon angioplasty (p less than .02). Histologic examination 4 weeks after the procedure revealed less fibrocellular proliferation after laser thermal angioplasty, whereas those vessels treated with balloon angioplasty demonstrated evidence of prior fracture and dissection of the vessel wall with more of a fibrocellular proliferative response.(ABSTRACT TRUNCATED AT 250 WORDS)

The precise location and progression of anastomotic hyperplasia and its possible relationship to flow disturbances was investigated in femoro-femoral Dacron grafts in 28 dogs. In 13 grafts, the outflow from the end-to-side downstream anastomosis was bidirectional (BDO), and in 15 it was unidirectional (UDO) (distally). Grafts were electively removed at intervals of two to 196 days or at the time of thrombosis. Each anastomosis and adjacent artery was perfusion-fixed and sectioned sagittally. The mean sagittal section was projected onto a digitized pad, and the total area of hyperplasia internal to the arterial internal elastic lamina and within the adjacent graft was integrated by computer. The location of the hyperplasia was compared with previously established sites of flow separation and stagnation. The observation was made that hyperplasia is significantly greater at the downstream, as compared with the upstream, anastomosis in both groups (BDO = p less than 0.001 and UDO = p less than 0.001) (analysis of variance for independent groups). Furthermore, this downstream hyperplasia was progressive with time (BDO p less than 0.01) (UDO p less than 0.01); Spearman Rank Correlation. There was no significant increase in the extent of downstream hyperplasia where flow separation was known to be greater (BDO). Five grafts failed (three BDO, two UDO), as a result of complete occlusion of the downstream anastomosis by fibrous hyperplasia. Transmission electron microscopy showed the hyperplasia to consist of collagen-producing smooth muscle cells. Anastomotic hyperplasia is significantly greater at the downstream anastomosis, is progressive with time, and is the primary cause of failure of Dacron arterial grafts in this model. Quantitative analysis of downstream anastomotic hyperplasia may be a valuable measure of the biocompatibility of Dacron grafts.