Cardiovascular risk factors and underlying pathology and prevalence of lipid plaques in women with acute coronary syndromes in different age groups

Background

An incidence of cardiovascular events increases with age in women. The relationship between cardiovascular risk factors, and the underlying pathology and the prevalence of lipid plaques has not been systematically studied in different age groups in women presented with acute coronary syndromes (ACS).

Purpose

We investigated the underlying pathology and the prevalence of lipid plaques in culprit lesions by optical coherence tomography (OCT) in women with different risk factors.

Methods

A total of 382 women who underwent pre-intervention OCT imaging were included. The underlying pathology and the prevalence of lipid plaques in the culprit lesion was compared between women with and without cardiovascular risk factors (i.e. hypertension, smoking, hyperlipidemia, diabetes mellitus, family history and chronic kidney disease) in three different age groups (<60 yr, 60–70 yr, >70 yr).

Results

The relative prevalence of plaque erosion was higher in younger women (<60 yr) and decreased with age (from 51% to 28%, p<0.001). There was no significant difference in the prevalence of lipid plaques between women with and without risk factors, except a higher prevalence of lipid plaques in current smokers compared to non-smokers (79% vs. 63%, p=0.003). In women with hyperlipidemia, the prevalence of lipid plaques was modest in young ages (<60 yr), but increased steeply with age (p<0.001). The increasing age trend for lipid plaque was also observed in women with hypertension (p=0.03) and current smokers (p=0.01). In women with diabetes mellitus and family history, the prevalence of lipid plaques was high even in young ages (<60 yr) and did not increase with age.

Conclusion

The prevalence of plaque erosion was higher in younger women (<60 yr) and decreased with age. Current smokers had significantly higher prevalence of lipid plaque. Patients with diabetes and positive family history had a higher prevalence of lipid plaque at young age. The prevalence of lipid plaques increased with age particularly in women with hyperlipidemia and hypertension.

Funding Acknowledgement

Type of funding sources: Foundation.

Diagnosis of coronary layered plaque by deep learning

Background/Introduction

Healed coronary plaques, morphologically characterized by a layered pattern, are signatures of previous plaque disruption and healing. Recent optical coherence tomography (OCT) studies showed that layered plaque is associated with vascular vulnerability and rapid plaque progression. However, the diagnosis of layered plaque requires expertise in OCT image interpretation and is susceptible to interobserver variability.

Purpose

We aimed to develop a deep learning (DL) model for an accurate diagnosis of layered plaque.

Methods

We developed a Visual Transformer (ViT)-based DL model emulating the cardiologists who review consecutive OCT frames to make a diagnosis (Figure 1), and compared it to the standard convolutional neural network (CNN) model. We used 302,415 cross-sectional OCT images from 873 patients collected from 9 sites: 237,021 images from 581 patients for training and internal validation from 8 sites, and 65394 images from 292 patients collected from another site for external validation.

Results

Model performances were evaluated using the area under the receiver operating characteristics (AUC). In the five-fold cross validation, the ViT-based model showed better performance than the standard CNN-based model with AUC of 0.886 (95% confidence interval [CI], 0.882–0.891) compared with 0.797 (95% CI, 0.790–0.804). The ViT-based model also outperformed the standard CNN-based model in the external validation, with an AUC of 0.857 (95% CI, 0.849–0.864) compared to 0.806 (95% CI, 0.797–0.815) (Figure 2).

Conclusion(s)

The ViT-based DL model will help cardiologists to make an accurate diagnosis of layered plaque, which might help to stratify the risk of future adverse cardiac events.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Mrs. Gillian Gray through the Allan Gray Fellowship Fund in Cardiology

Level of vascular inflammation is higher in acute coronary syndromes compared to chronic coronary disease

Background

Vascular inflammation has been recognized as one of the key factors in the pathogenesis of acute coronary syndromes (ACS). Peri-coronary adipose tissue (PCAT) attenuation by computed tomography angiography (CTA) has emerged as a marker specific for coronary artery inflammation. We examined the relationship between clinical presentation and coronary artery inflammation assessed by PCAT attenuation and coronary plaque characteristics.

Methods

Patients with ACS or stable angina pectoris (SAP) who underwent pre-intervention coronary CTA and optical coherence tomography (OCT) were enrolled. PCAT attenuation was measured around the culprit lesion and in the proximal 40 mm of all coronary arteries. PCAT attenuation and OCT findings were compared between patients with ACS versus SAP.

Results

Among 471 patients (ACS: 198, SAP: 273), PCAT attenuation was higher in ACS patients than in SAP patients both at the culprit plaque level (−67.5±9.6 Hounsfield unit [HU] vs. −71.5±11.0 HU, p<0.001) and the culprit vessel level (−68.3±7.7 HU vs. −71.1±7.9 HU, p<0.001). The mean PCAT attenuation of all 3 coronary arteries was also significantly higher in ACS patients than in SAP patients (−68.8±6.3 HU vs. −70.5±7.1 HU, p=0.007). After adjusting patient characteristics, not only thin-cap fibroatheroma (OR: 2.44; 95% CI: 1.63–3.65) and macrophages (OR: 2.07; 95% CI: 1.34–3.21) but also PCAT attenuation in the culprit plaque (OR: 1.04; 95% CI: 1.02–1.06) was associated with the clinical presentation of ACS.

Conclusions

PCAT attenuation at culprit plaque, culprit vessel, and pan-coronary levels was higher in ACS patients than in SAP patients. Vascular inflammation appears to play a crucial role in the development of ACS.

Funding Acknowledgement

Type of funding sources: None.

P2651Seasonal variations in the pathogenesis of acute coronary syndromes

Background

Seasonal variations in acute coronary syndrome (ACS) has been known with the winter being the peak in incidence and mortality. However, underlying pathophysiology for this variation has not been studied.

Purpose

We sought to compare pathobiology of the culprit lesions assessed by optical coherence tomography (OCT) among the four seasons.

Methods

Patients with ACS who underwent OCT were recruited from 6 countries in the Northern Hemisphere. The prevalence of 3 most common pathologies, plaque rupture, plaque erosion and calcified plaque, and other features of coronary plaques were compared among the four seasons.

Results

In 1113 patients with ACS, 284 (25%) patients were admitted in spring, 243 (22%) patients in summer, 290 (26%) patients in autumn and 296 (27%) patients in winter. The proportion of underlying 3 pathologies was significantly different in each season (prevalence of plaque rupture, plaque erosion, calcified plaque was 50%, 39%, and 11%, respectively in the spring; 44%, 43%, and 13% in the summer; autumn: 49%, 39%, and 12% in the autumn; 57%, 30%, and 13% in the winter; P=0.039). The proportion of plaque rupture was higher in winter but lower in summer, and that of plaque erosion was higher in summer, but lower in winter. Maximum and minimum temperatures on the day of OCT procedure were significantly lower in the plaque rupture group than in the plaque erosion group (P=0.02 and P=0.012, respectively). In the rupture group, the prevalence of hypertension was significantly higher in winter, but in the erosion group, it was not different among the four seasons.

Figure 1. The proportion of culprit lesion characteristics were significantly different among the 4 season groups. (P=0.039) The proportion of plaque rupture was significantly higher in winter but lower in summer. In contrast, the proportion of plaque erosion was higher in summer, but lower in winter.

Conclusions

Seasonal variation of the underlying mechanisms of ACS reflects different pathobiology. The proportion of plaque rupture is highest in winter and the proportion of plaque erosion is highest in summer. A different approach may be needed for the prevention and treatment of ACS depending on the season of its occurrence.

108Biologic significance of healed culprit plaques in stable angina versus acute coronary syndromes

Background

Healed plaques, the signature of prior subclinical plaque destabilization, are frequently found in autopsy studies and have recently been described in patients with acute coronary syndromes (ACS).

Objectives

To compare the prevalence and features of plaque vulnerability of healed culprit lesions in stable angina pectoris (SAP) versus ACS patients by using Optical Coherence Tomography (OCT).

Methods

A total of 752 patients were included: 376 patients with SAP were selected using propensity score matching, comparable to 376 patients with ACS. Healed plaques were identified using established criteria, defined as layers of different optical density on OCT. Healed plaque prevalence along with angiographic and OCT findings were compared between the two groups.

Results

Healed plaques were more frequent in SAP than in ACS patients (42.0% vs 28.7%, p<0.001). LDL-cholesterol and high sensitive C-reactive protein (hs-CRP) levels were significantly lower in SAP patients with layered plaque as compared to ACS patients with layered plaque [97.9±36.9 mg/dL vs 116.7±39.2 mg/dL, p<0.001; 0.20 (0.10–0.83) mg/L vs 4.98 (1.00–11.32) mg/L, p<0.001, respectively]. Thin-cap fibroatheroma, macrophage accumulation and microvessels were significantly less frequent in layered plaques in SAP patients as compared to those in ACS patients (12.7% vs 56.5%, p<0.001, 7.0% vs 79.6%, p<0.001, and 20.3% vs 43.5%, p<0.001, respectively). Calcifications were found more frequently among layered plaques in SAP patients than in ACS patients (51.3% vs 33.6%, p=0.006).

Conclusions

Healed plaques, detected more frequently in SAP than in ACS patients, portend different atherosclerotic backgrounds. In SAP patients, plaque destabilization frequently does not lead to occlusive thrombosis, possibly due to low level of local vulnerability and systemic inflammation. In ACS patients, the presence of high level of local vulnerability and systemic inflammation may play an important role in occlusive thrombus formation, resulting in terminating the cycles of subclinical thrombosis and healing.

Biolayer interferometry predicts ELISA performance of monoclonal antibody pairs for Plasmodium falciparum histidine-rich protein 2

Predicting antibody pair performance in a sandwich format streamlines development of antibody-based diagnostics and laboratory research tools, such as enzyme-linked immunosorbent assays (ELISAs) and lateral flow immunoassays (LFAs). We have evaluated panels of monoclonal antibodies against the malarial parasite biomarker Plasmodium falciparum histidine rich protein 2 (HRP2), including 9 new monoclonal antibodies, using biolayer interferometry (BLI) and screened antibody pairs in a checkerboard ELISA. This study showed BLI predicts antibody pair ELISA performance for HRP2. Pairs that included capture antibodies with low off-rate constants and detection antibodies with high on-rate constants performed best in an ELISA format.

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Kinetic parameters of 15 anti-HRP2 antibodies are measured by biolayer interferometry.

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Kinetic constants are compared to a checkerboard ELISA of 225 antibody pairs.

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Biolayer interferometry predicts antibody pair performance for HRP2 ELISA.

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Capture mAbs with low k_off and detection mAbs with high k_on are best in HRP2 ELISA.

Suppression of T-cell proliferation by and B7-H1 expression on human liver-derived stem cells

BACKGROUND

Many types of stem cells have been widely used for the treatment of liver diseases. The therapeutic effect of stem cells is predominantly based on the immune regulatory properties of these cells.

METHODS

We isolated human liver stem cells (HLSCs), which are considered intrahepatic stem cells, and examined their suppression of T-cell proliferation induced by phytohemagglutinin.

RESULTS

HLSCs inhibited phytohemagglutinin-induced T-cell proliferation not only in direct co-culture but also in indirect co-culture in a cell number-dependent manner. That is, T-cell proliferation was substantially inhibited by cell-to-cell contact regardless of soluble factor(s). B7-H1, a co-inhibitory molecule that relies on cell-to-cell contact, was found to be constitutively expressed at low levels on HLSCs. Furthermore, its expression was upregulated moderately by tumor necrosis factor-α and dramatically by interferon-γ.

CONCLUSIONS

These results suggest that HLSCs would have therapeutic effects through T-cell suppression in acute liver diseases.

B7-H1 inhibits T cell proliferation through MHC class II in human mesenchymal stem cells

B7-H1 on mesenchymal stem cells (MSCs) is known to modulate immune response. However, its expression pattern and exact immunomodulatory mechanism are unclear. In this study, we examined the immunomodulatory mechanism through the expression pattern of B7-H1 and major histocompatibility complex class II in various MSCs. Human bone marrow, adipose tissue, and cord blood MSCs were isolated and cultured. B7-H1, HLA-ABC, and HLA-DR expression on MSCs by interferon-γ (IFN-γ) was detected time-dependently by flow cytometry. The inhibitory effect of MSCs on T lymphocytes was observed in phytohemagglutinin antigen-induced T cell proliferation assay. The expression of B7-H1 was rapidly induced, but the expression of HLA-DR was induced at 48 hours after IFN-γ treatment. The inhibitory effect of MSCs on T cell proliferation could be restored when the anti-B7-H1 monoclonal antibody was used to block the B7-H1, or when the HLA-DRα small interfering RNA was used to interfere with its expression. These results show that MSCs could inhibit the T cell proliferation and activation by B7-H1 depending on the presence of HLA-DR. Therefore, MSCs would have a strong effect on immune diseases such as graft-versus-host disease and autoimmune diseases when MSCs are primed with IFN-γ 48 hours before transplantation.

Effect of multiple infections with white spot syndrome virus and Vibrio anguillarum on Pacific white shrimp Litopenaeus vannamei (L.): mortality and viral replication

Multiple infections are commonly found in practical shrimp culture and may cause more serious consequences than infections by one pathogen only. Therefore, this study was conducted to evaluate the effect of multiple infections with white spot syndrome virus (WSSV) and Vibrio anguillarum on Pacific white shrimp Litopenaeus vannamei (L.), mortality, WSSV replication in vivo and host immune response. In the WSSV single-infection group (WSSV load, 2 × 10(2) copies μL(-1)), mean cumulative mortality was 29.2%. In the V. anguillarum single-infection group, cumulative mortality was 12.5% when shrimp were challenged by 10(5) CFU mL(-1) of bacteria. In the co- and super-infection groups, 37.5% and 50% cumulative mortalities, respectively, were observed at a lower bacterial concentration of 10(3) CFU mL(-1), suggesting that shrimp with multiple infections died earlier and more frequently than singly infected shrimp. WSSV load after injection was tracked over time by TaqMan quantitative PCR. WSSV load increased more rapidly in the multiple-infection groups than in the single-infection group. Additionally, mRNA expression of the genes encoding prophenoloxidase 1 and 2, which are closely involved in innate immunity in shrimp, was down-regulated more extensively in multiple-infection groups than in single-infection groups, as indicated by quantitative reverse-transcription PCR.

In vitro evaluation of migratory capacity of human liver stem cells influenced by soluble factors

Although several studies have addressed the engraftment of stem cells into the liver, the exact mechanisms in vivo remain unclear. In this study, we investigated the effects of soluble factors on cell migration using purified, expanded human liver stem cells (HLSCs) obtained from a pediatric liver resection. Using a in vitro transwell migration assay, we evaluated the migratory capacity of HLSCs under the influence of the cytokines tumor necross factor- [TNF]-α, interleukin [IL]-6, and interferon (IFN)-γ or the growth factors vascular endothelial growth factor [VEGF], basic fibroblast growth factor [bFGF], and hepatocyte growth factor [HGF], which are known to be highly secreted during liver injury. We also evaluated the migratory capacity indirectly influenced by cryopreserved human hepatocytes. The migration across the transwell membrane was promoted by VEGF, bFGF, TNF-α, IFN-γ, or hepatocytes. The cryopreserved human hepatocytes especially induced significant migration. These results suggested the presence of unidentified soluble factors from hepatocytes. This experiment described a reliable system for quantitative migration studies to broaden our understanding of the directional nature of cell migration.

Disagreement between formal and medical record criteria for the diagnosis of acute coronary syndrome

OBJECTIVES

To measure agreement between formal and medical record criteria for the diagnosis of acute coronary syndrome (ACS) among patients undergoing an emergency department evaluation for potential acute coronary symptoms.

METHODS

Cases of ACS were determined by both formal (World Health Organization 1984 criteria for acute myocardial infarction [AMI], Braunwald criteria for unstable angina pectoris [UAP]) and medical record criteria. In the latter, a diagnosis was made if providers indicated AMI or UAP anywhere in the medical record. All information included in formal criteria was available to clinicians establishing the medical record diagnosis. The two criteria for diagnosis were compared, and a kappa value was recorded. Two blinded observers adjudicated discordant cases, with a kappa value recorded. Disagreements between these two coinvestigators were resolved by a Delphi technique.

RESULTS

A total of 375 eligible subjects were enrolled, of whom 65 (17%; 45 AMI, 20 UAP) had ACS by both sets of criteria. Formal and medical record criteria disagreed in 32 subjects. This represented 9% (95% confidence interval = 6% to 12%) of the overall study population but 33% (95% confidence interval = 23% to 43%) of subjects with possible ACS. Coinvestigators acting as judges and blinded to each other's determinations agreed that 25 of these subjects had ACS and three did not; they disagreed on four subjects (kappa = 0.54). Among these four subjects, a Delphi consensus technique determined that two subjects had AMI and two had no ACS.

CONCLUSIONS

In a single-site study, among subjects who have possible ACS as determined by either or both formal and medical record criteria, these two sets of criteria disagree in almost one third of cases. Among discordant cases, even two expert judges frequently disagreed on the final diagnosis. A modified Delphi technique to address these disagreements is described.

The comparison between optical coherence tomography and intravascular ultrasound

Coronary angiography, despite its long history, has well recognized limitations, arising in part from the inability to image a three dimensional structure in a single plane. Furthermore the angiographic image of the arterial lumen conceals atherosclerotic processes that occur within the arterial wall. Alternative imaging techniques have evolved as an adjunct to angiography in an attempt to overcome these limitations. Two such invasive techniques are intravascular ultrasound and optical coherence tomography. Intravascular ultrasound allows tomographic imaging of long segments of the coronary tree, highlighting the arterial lumen as well as the arterial wall. Over the last 13 years intravascular ultrasound has enhanced our understanding of the pathophysiology of atherosclerosis, and the mechanisms involved in coronary intervention. Optical coherence tomography is an optical analogue of intravascular ultrasound that has recently reached coronary application. Its superior resolution results in improved diagnostic potential, particularly for vulnerable plaque in which the thin fibrous cap often measures 10-50 mm. The similarities, contrasts and applications of these two imaging techniques in terms of design, image interpretation, and future directions forms the subject of this review.

Vascular complications after hemostatic puncture closure device (Angio-Seal) are not higher in overweight patients

BACKGROUND

Angio-Seal (Daig Corporation, Minnetonka, Minnesota) allows earlier discharge from the hospital after coronary angiography. Manual compression in overweight patients after percutaneous procedures is associated with a higher incidence of groin complications. The purpose of this study was to determine if a vascular closure device could be safely used without increasing the risk of vascular complications in overweight patients.

METHODS

A total of 198 patients who received the 6 French Angio-Seal device after diagnostic coronary angiography were divided into 3 groups. Group A included patients with a body mass index (BMI) of < or = 25, group B with BMI between 25 and 30, and group C with BMI > or = 30. Patients were followed for groin complications during their hospital stay.

RESULTS

Complication rates were comparable between the 3 groups. Groin complications occurred in 11% in group A, 5% in group B and 6% in group C.

CONCLUSION

After diagnostic cardiac catheterization, a vascular closure device such as Angio-Seal can be safely used in overweight patients.

Transgenic live-bearing fish and crustaceans produced by transforming immature gonads with replication-defective pantropic retroviral vectors

Transgenic animals have been routinely produced by microinjecting or electroporating naked DNA into 1-cell-stage embryos or unfertilized eggs. However, these techniques are inapplicable to live-bearing fish and many crustacean species for which unfertilized or newly fertilized eggs are not readily obtainable. In the present study, replication-defective pantropic retroviral vectors carrying a reporter gene (neo(R) or beta-gal) were used to directly transform the immature ovary or testis of a live-bearing fish (Poeciliopsis lucida) and crayfish (Procambarus clarkii). The fraction of the progeny derived from these treated individuals shown to contain the neo(R) reporter gene by an assay based on polymerase chain reaction (PCR) was significant. The PCR-positive individuals were crossed with nontransgenic individuals, and about 50% of the resulting progeny carried the transgene, suggesting that the F(1) animals are germline transgenic. Integration of the transgenes was confirmed by detecting the junction fragments of the genomic DNA associated with transgene constructs. Expression of reporter genes was detected by a reverse transcription-nested PCR assay. These results showed that transgenic live-bearing fish and crustaceans could be easily produced by directly transforming the immature gonads with replication-defective pantropic retroviral vectors.

A risk score system for predicting adverse outcomes and magnitude of benefit with glycoprotein IIb/IIIa inhibitor therapy in patients with unstable angina pectoris

Clinical outcomes of patients with unstable angina are variable. We sought to identify predictors of adverse clinical outcomes in patients with unstable angina and to investigate whether these factors would predict the magnitude of benefit achieved with platelet glycoprotein IIb/IIIa inhibition. We analyzed 20 variables in the 1,915 patients enrolled in the Platelet Receptor Inhibition for Ischemic Syndrome Management in Patients Limited by Unstable Signs and Symptoms trial. Five independent predictors were identified: age >65 years, prior coronary artery bypass grafting, antecedent aspirin use, antecedent beta-blocker use, and ST depressions on the presenting electrocardiogram. A risk score system was created using these predictors in which patients were assigned 1 point for the presence of each risk factor. There was a progressive increase in the rate of the composite end point of death, myocardial infarction, or refractory ischemia at 7 days with an increasing number of risk factors. For patients treated with heparin alone, the composite end point event rate was 6.5% in the group with 0 or 1 predictor, 14.6% in the group with 2 predictors, 22.7% in the group with 3 predictors, and 37.1% in the group with 4 or 5 predictors (p <0.00001). When dividing patients into low- (0 or 1 point), medium- (2 or 3 points), and high-risk (4 or 5 points) groups, the addition of tirofiban to heparin therapy was associated with no significant benefit in the low-risk group, a 5.2% absolute reduction in the medium-risk group (p = 0.05), and a 16% absolute reduction in the high-risk group (p = 0.0055). Thus, we have developed a risk score system using 5 variables that can be used to identify patients at high risk for death and cardiac ischemic events and who experience the greatest benefit from the addition of a glycoprotein IIb/IIIa inhibitor to their treatment regimen.

Production of transgenic live-bearing fish and crustaceans with replication-defective pantropic retroviral vectors

Transgenic fish have been routinely produced by microinjecting or electroporating foreign DNA into one-cell stage embryos or unfertilized eggs. While both techniques are effective in producing transgenic fish species from which unfertilized or newly fertilized eggs can be easily obtained, these techniques are not applicable to live-bearing fish and many crustacean species where unfertilized or newly fertilized eggs are not readily available. In this paper, we describe a new method of introducing foreign DNA into the live-bearing fish, Poeciliposis lucida, and crayfish, Procambarus clarkii, by directly transforming the immature ovary or testis of these animals with replication-defective pantropic retroviral vectors carrying a reporter gene (neo(R)). A significant fraction of the progeny derived from these treated animals contains the neo(R) reporter gene, determined by a PCR-based assay. The PCR-positive individuals were crossed with nontransgenic individuals, and about 50% of the resulting progeny carried the transgene, suggesting that the F(1) animals are germline transgenic. Integration of the transgenes was confirmed by detecting the junction fragments of the genomic DNA associated with transgene constructs. The expression of reporter genes was detected by reverse transcription (RT) PCR assay. These results showed that foreign genes could be reproducibly transferred into live-bearing fish and crustaceans by directly transforming the immature gonads with replication-defective pantropic retroviral vectors.

Elevation in serum troponin I predicts the benefit of tirofiban

BACKGROUND

Elevations in serum troponins among patients with acute coronary syndromes have been shown to identify those patients who are at high risk for poor outcome and who accrue larger relative benefits from aggressive antiplatelet and antithrombotic therapies. We studied a group of patients from the PRISM-PLUS trial to explore whether simply using serum troponin I, a serum marker of cardiac injury, could predict benefit of GP IIb/IIIa receptor antagonism with tirofiban.

METHODS AND RESULTS

For this study, the subjects consisted of 55 patients receiving the combination therapy of tirofiban/heparin, and 55 receiving heparin alone. The baseline characteristics were similar between the two treatment groups. Serial blood samples were obtained over the first 24-hour period following randomization to study drug, and were analyzed for troponin I (TnI) levels. Among those patients with elevated serum TnI (>0.5 ng/ml), the 30-day event rate for death or myocardial infarction (MI) was reduced from 20.6% among the heparin only group to 3.6% for those treated with the combination of tirofiban/heparin, an absolute risk reduction of 17% and relative risk reduction of 83% (p=0.06). Among the TnI negative patients, the rates of death/MI at 30 days were 9.5% and 11.1% among the combination and heparin treated groups respectively (p=NS).

CONCLUSION

Irrespective of high-risk clinical factors, including ST segment depression, these data support the hypothesis that serum troponins identify those who benefit from aggressive antiplatelet therapy with tirofiban.

Argatroban anticoagulant therapy in patients with heparin-induced thrombocytopenia

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is an immune-mediated syndrome caused by heparin. Complications range from thrombocytopenia to thrombocytopenia with thrombosis. We report a prospective, historical- controlled study evaluating the efficacy and safety of argatroban, a direct thrombin inhibitor, as anticoagulant therapy in patients with HIT or HIT with thrombosis syndrome (HITTS).

METHODS AND RESULTS

Patients with HIT (isolated thrombocytopenia, n=160) or HITTS (n=144) received 2 microgram. kg(-1). min(-1) IV argatroban, adjusted to maintain the activated partial thromboplastin time 1.5 to 3.0 times baseline value. Treatment was maintained for 6 days, on average. Clinical outcomes over 37 days were compared with those of 193 historical control subjects with HIT (n=147) or HITTS (n=46). The incidence of the primary efficacy end point, a composite of all-cause death, all-cause amputation, or new thrombosis, was reduced significantly in argatroban-treated patients versus control subjects with HIT (25.6% versus 38.8%, P=0.014). In HITTS, the composite incidence in argatroban-treated patients was 43.8% versus 56.5% in control subjects (P=0.13). Significant between-group differences by time-to-event analysis of the composite end point favored argatroban treatment in HIT (P=0.010) and HITTS (P=0.014). Argatroban therapy, relative to control subjects, also significantly reduced new thrombosis and death caused by thrombosis (P<0.05). Argatroban-treated patients achieved therapeutic activated partial thromboplastin times generally within 4 to 5 hours of starting therapy and, compared with control subjects, had a significantly more rapid rise in platelet counts (P=0.0001). Bleeding events were similar between groups.

CONCLUSIONS

Argatroban anticoagulation, compared with historical control subjects, improves clinical outcomes in patients who have heparin-induced thrombocytopenia, without increasing bleeding risk.

Fundamental concepts in the pathobiology of heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is among the most common causes of drug-related immune-mediated thrombocytopenia. It is a unique syndrome, in that despite the fact that thrombocyto-penia is the major laboratory manifestation of HIT, its major complication is a highly morbid (and commonly fatal) thrombotic diathesis, known as the HIT with thrombosis syndrome (HITTS). The pathogenesis of HIT and HITTS has been recently elucidated, and involves an immune response against epitopes within circulating heparin-platelet factor-4 (PF4) complexes. This leads to cross-linking and activation of platelets, increasing the risk for thromboses. Furthermore, significant immunological cross-reactivity occurs between endothelial-cell bound PF4 and the HIT antibody, which may lead to endothelial damage, activation, and hyperplasia. This complex process leads to a hypercoagulable state, which may lead to overt thromboses.

Balloon deflection technique: A method to facilitate entry of a balloon catheter into a deployed stent

The entry of an angioplasty balloon into a coronary stent is occasionally difficult due to poorly expanded stent struts or calcified tissue blocking balloon passage. We describe a simple technique using a second guidewire and balloon to facilitate entry into the stent. Cathet. Cardiovasc. Intervent. 51:312-313, 2000.

Combination of a direct thrombin inhibitor and a platelet glycoprotein IIb/IIIa blocking peptide facilitates and maintains reperfusion of platelet-rich thrombus with alteplase

We sought to determine the efficacy of the combination of argatroban, a direct thrombin inhibitor, and G4120, a platelet glycoprotein (GP) IIb/IIIa blocker, to enhance thrombolysis with alteplase. Platelet-rich thrombus in the rabbit arterial thrombosis model is relatively resistant to alteplase despite the addition of aspirin and heparin. The adjunctive use of either direct thrombin inhibitors or GP IIb/IIIa inhibitors in thrombolysis has been investigated with encouraging, but limited, success. The usefulness of combining both agents as adjunctive therapy to thrombolysis has not been fully explored. Following platelet-rich thrombus formation in the rabbit, argatroban (3 mg/kg), G4120 (0.5 mg/kg), G4120 plus heparin (200 U/kg), or G4120 plus argatroban were intravenously infused over 60 minutes. Alteplase was given as intravenous boluses (0.45 mg/kg) at 15-minute intervals up to 4 doses or until reperfusion. Blood flow and bleeding time were monitored for 2 hours. The combination of G4120 plus argatroban resulted in a persistent patency in 5 of 7 animals compared with 0 of 6 for argatroban alone (p=0.02), 1 of 6 for G4120 alone (p=0.08), and 2 of 6 for G4120 plus heparin (p=0.2). Although during the infusion the bleeding times were longer in the groups that received G4120 (26+/-7.7 minutes vs. 14+/-10 minutes, p<0.05), by the end of the experiment there were no statistically significant differences. Similarly, during the infusion the activated partial thromboplastin times (aPTT) was higher in groups that received heparin or argatroban (99+/-51 seconds vs. 32+/-7.6 seconds, p<0.001), but by the end of the experiment the aPTTs had returned to close to baseline in all groups except the G4120 plus heparin group. These results suggest that lysis of platelet-rich thrombus with alteplase requires the addition of both potent platelet and thrombin inhibitors. Specifically designed agents, G4120 and argatroban, are effective without additional increased risk for bleeding.

Effects of tirofiban plus heparin versus heparin alone on troponin I levels in patients with acute coronary syndromes

Elevated serum troponins following an acute coronary syndrome (ACS) predict a poor clinical outcome. Glycoprotein (GP) IIb/IIIa inhibitors reduce adverse clinical outcomes in patients with ACS, although their effect on serum troponin I (TnI) in this setting has not been described. We therefore studied the effects of the GP IIb/IIIa inhibitor tirofiban on serum TnI levels in a group of patients in the Platelet Inhibition in Ischemic Syndrome Management in Patients Limited by Unstable Signs and Symptoms trial. Serial blood samples were obtained in 53 patients receiving the combination therapy of tirofiban/heparin and in 52 receiving heparin alone, and were analyzed for baseline, peak, and mean concentrations of TnI. Baseline TnI levels were not different between the combination therapy and heparin-only groups (1.6 +/- 3.0 vs 3.1 +/- 6.7 ng/ml, p = 0.15). The peak TnI level was significantly lower in the combination therapy group than in the heparin group (5.2 +/- 8.3 vs 15.5 +/- 29.1 ng/ml, p = 0.017), and mean levels over the initial 24-hour period were also significantly lower in the combination therapy group (3.2 +/- 5.0 vs 8.5 +/- 14.8 ng/ml, p = 0.016). In univariate analysis, combination therapy was associated with lower TnI levels, whereas in a multivariate model, the lower peak and mean TnI levels as a consequence of tirofiban/heparin compared with heparin monotherapy remained significant (peak, p = 0.029; mean, p = 0.035). Among patients with negative TnI at baseline, treatment with the combination of tirofiban/heparin compared with heparin monotherapy still resulted in significantly lower peak (2.5 +/- 5.4 vs 14.6 +/- 32.8 ng/ml, p = 0.024) and mean (1.2 +/- 2.6 vs 6.9 +/- 15.8 ng/ml, p = 0.029) TnI levels. In patients with ACS, therapy with the combination of tirofiban and heparin (compared with heparin treatment alone) resulted in lower serum TnI levels, suggesting reduced myocardial injury.

Prevalence of early left ventricular thrombus after primary coronary intervention for acute myocardial infarction

The prevalence of left ventricular (LV) thrombus after acute myocardial infarction (AMI) has been reported high at 20-60%. Current reperfusion therapies such as thrombolysis have shown a trend toward reducing the incidence of LV thrombosis. However, the prevalence of LV thrombus after primary percutaneous coronary intervention (PCI) for AMI has not been systematically studied. At Massachusetts General Hospital 71 consecutive patients who underwent primary PCI for acute ST elevation MI were reviewed for the prevalence of LV thrombus evaluated by echocardiography. Echocardiography was performed within 5 days of infarction. PCI was successful in all patients. The time delay from symptom onset to intervention was 191 minutes. Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow was achieved in more than 80% of cases. Only 3 patients (4%) had echocardiographic evidence of LV thrombus. All 3 patients had anterior infarctions. The incidence among patients with anterior MI was 10% (3 of 30 patients). The prevalence of LV thrombus in patients treated with primary PCI for AMI is low (4%).

The use of glycoprotein IIb/IIIa inhibitors in patients with coronary artery disease

Platelet membrane glycoprotein IIb/IIIa inhibitors, a new class of potent antiplatelet agents, have been used in the treatment of acute coronary syndromes as well as in the prevention of complications after percutaneous coronary interventions. Approximately 50,000 patients with coronary artery disease have been enrolled in randomized studies of glycoprotein IIb/IIIa inhibitors. The purpose of this article is to review the pharmacology of glycoprotein IIb/IIIa inhibitors, the results of the clinical trials using these agents, and their current use in percutaneous coronary interventions and the treatment of acute coronary syndromes.

Porcine coronary imaging in vivo by optical coherence tomography

OBJECTIVE

A high-resolution coronary artery imaging modality has the potential to address important diagnostic and management problems in cardiology. Optical coherence tomography (OCT) is a promising new optical imaging technique with a resolution of approximately 10 microm. The purpose of this study was to use a new OCT catheter to demonstrate the feasibility of performing OCT imaging of normal coronary arteries, intimal dissections, and deployed stents in vivo.

METHODS AND RESULTS

Normal coronary arteries, intimal dissections, and stents were imaged in five swine with OCT and compared with intravascular ultrasound (IVUS). In the normal coronary arteries, visualization of all of the layers of the vessel wall was achieved with a saline flush, including the intima which was not identified by IVUS. Following dissection, detailed layered structures including intimal flaps, intimal defects, and disruption of the medial wall were visualized by OCT. IVUS failed to show clear evidence of intimal and medial disruption. Finally, the microanatomic relationships between stents and the vessel walls were clearly identified only by OCT.

CONCLUSIONS

In this preliminary experiment, we have demonstrated that in vivo OCT imaging of normal coronary arteries, intimal dissections, and deployed stents is feasible, and allows identification of clinically relevant coronary artery morphology with high-resolution and contrast.

Primary versus rescue percutaneous coronary intervention in patients with acute myocardial infarction

OBJECTIVE

To compare angiographic and clinical outcomes of patients with acute myocardial infarction (AMI) who underwent primary percutaneous coronary intervention (PCI) versus rescue PCI following failed thrombolysis.

BACKGROUND

Patients presenting with AMI are treated either with primary PCI or with thrombolysis. When thrombolysis fails, rescue PCI is performed.

METHODS AND RESULTS

We compared the outcome of 105 consecutive patients with AMI who underwent either primary PCI (60 patients) or rescue PCI (45 patients) between January 1997 and January 1999. The patients were followed for up to 6 months. Time delay to reperfusion was significantly longer in the rescue PCI group (354 vs. 189 min; p < 0.001). The majority of patients received a stent (93%). Glycoprotein (GP) IIb/IIIa inhibitors were used in 53% of patients in the primary PCI group and in 22% in the rescue group. TIMI grade 3 flow was achieved in 93.3% of patients in the primary PCI group and in 88.8% in the rescue group (p = 0.08). Post-procedure ejection fraction was 53% in the primary PCI group and 47% in the rescue group (p = 0.014). A composite endpoint of death, recurrent MI, repeat PCI, coronary artery bypass grafting (CABG) and recurrent angina at 6 months occurred in 35% of the patients in the primary PCI group and 26.7% in the rescue group (p = 0.36).

CONCLUSION

Despite a significant delay to reperfusion and a lower immediate post-procedure ejection fraction, the clinical outcome of patients treated with rescue PCI following failed thrombolysis appears to be similar to that of patients treated with primary PCI at 6 months.

Cbl-b regulates the CD28 dependence of T-cell activation

Whereas co-stimulation of the T-cell antigen receptor (TCR) and CD28 triggers T-cell activation, stimulation of the TCR alone may result in an anergic state or T-cell deletion, both possible mechanisms of tolerance induction. Here we show that T cells that are deficient in the adaptor molecule Cbl-b (ref. 3) do not require CD28 engagement for interleukin-2 production, and that the Cbl-b-null mutation (Cbl-b(-/-)) fully restores T-cell-dependent antibody responses in CD28-/- mice. The main TCR signalling pathways, such as tyrosine kinases Zap-70 and Lck, Ras/mitogen-activated kinases, phospholipase Cgamma-1 and Ca2+ mobilization, were not affected in Cbl-b(-/-) T cells. In contrast, the activation of Vav, a guanine nucleotide exchange factor for Rac1/Rho/CDC42, was significantly enhanced. Our findings indicate that Cbl-b may influence the CD28 dependence of T-cell activation by selectively suppressing TCR-mediated Vav activation. Mice deficient in Cbl-b are highly susceptible to experimental autoimmune encephalomyelitis, suggesting that the dysregulation of signalling pathways modulated by Cbl-b may also contribute to human autoimmune diseases such as multiple sclerosis.

Frequency of silent myocardial ischemia following coronary stenting

To detect silent myocardial ischemia, 12-lead continuous electrocardiographic monitoring was performed in patients undergoing 1-vessel coronary stenting. Despite successful angiographic results, one third of the patients experienced silent myocardial ischemia during the postprocedural period.

Heparin induced thrombocytopenia: diagnosis and contemporary antithrombin management

Heparin-induced thrombocytopenia (HIT) may be complicated by severe thrombotic complications and death. Currently no specific laboratory test is available to make the diagnosis. When HIT is clinically suspected, heparin should be discontinued immediately. While no specific therapy for HIT exists, there is increasing evidence that acute antithrombin therapy may significantly reduce morbidity and mortality. Among several agents, the direct antithrombins, such as r-hirudin and argatroban, look the most promising for acute treatment.

A multicenter, randomized study of argatroban versus heparin as adjunct to tissue plasminogen activator (TPA) in acute myocardial infarction: myocardial infarction with novastan and TPA (MINT) study

OBJECTIVES

This study examined the effect of a small-molecule, direct thrombin inhibitor, argatroban, on reperfusion induced by tissue plasminogen activator (TPA) in patients with acute myocardial infarction (AMI).

BACKGROUND

Thrombin plays a crucial role in thrombosis and thrombolysis. In vitro and in vivo studies have shown that argatroban has advantages over heparin for the inhibition of clot-bound thrombin and for the enhancement of thrombolysis with TPA.

METHODS

One hundred and twenty-five patients with AMI within 6 h were randomized to heparin, low-dose argatroban or high-dose argatroban in addition to TPA. The primary end point was the rate of thrombolysis in myocardial infarction (TIMI) grade 3 flow at 90 min.

RESULTS

TIMI grade 3 flow was achieved in 42.1% of heparin, 56.8% of low-dose argatroban (p = 0.20 vs. heparin) and 58.7% of high-dose argatroban patients (p = 0.13 vs. heparin). In patients presenting after 3 h, TIMI grade 3 flow was significantly more frequent in high-dose argatroban versus heparin patients: 57.1% versus 20.0% (p = 0.03 vs. heparin). Major bleeding was observed in 10.0% of heparin, and in 2.6% and 4.3% of low-dose and high-dose argatroban patients, respectively. The composite of death, recurrent myocardial infarction, cardiogenic shock or congestive heart failure, revascularization and recurrent ischemia at 30 days occurred in 37.5% of heparin, 32.0% of low-dose argatroban and 25.5% of high-dose argatroban patients (p = 0.23).

CONCLUSIONS

Argatroban, as compared with heparin, appears to enhance reperfusion with TPA in patients with AMI, particularly in those patients with delayed presentation. The incidences of major bleeding and adverse clinical outcome were lower in the patients receiving argatroban.

Identification of a novel activation-inducible protein of the tumor necrosis factor receptor superfamily and its ligand

Among members of the tumor necrosis factor receptor (TNFR) superfamily, 4-1BB, CD27, and glucocorticoid-induced tumor necrosis factor receptor family-related gene (GITR) share a striking homology in the cytoplasmic domain. Here we report the identification of a new member, activation-inducible TNFR family member (AITR), which belongs to this subfamily, and its ligand. The receptor is expressed in lymph node and peripheral blood leukocytes, and its expression is up-regulated in human peripheral mononuclear cells mainly after stimulation with anti-CD3/CD28 monoclonal antibodies or phorbol 12-myristate 13-acetate/ionomycin. AITR associates with TRAF1 (TNF receptor-associated factor 1), TRAF2, and TRAF3, and induces nuclear factor (NF)-kappaB activation via TRAF2. The ligand for AITR (AITRL) was found to be an undescribed member of the TNF family, which is expressed in endothelial cells. Thus, AITR and AITRL seem to be important for interactions between activated T lymphocytes and endothelial cells.

Comparison of primary coronary stenting to primary balloon angioplasty with stent bailout for the treatment of patients with acute myocardial infarction

This study compares the immediate and long-term outcomes of a primary coronary stenting strategy with primary balloon angioplasty with stent bailout in the treatment of patients with acute myocardial infarction (AMI). One hundred forty-seven consecutive patients who underwent primary balloon angioplasty with stent bailout (n = 94) or primary stenting (n = 53) for AMI were clinically followed for 8.1 +/- 5.7 and 8.5 +/- 4.5 months, respectively. Immediate results, as well as in-hospital and long-term ischemic events (death, reinfarction, and repeat revascularization) were compared between both groups. Angiographic success was 91.5% in the balloon angioplasty group and 94% in the stent group. In-hospital and late follow-up combined ischemic events were 22 of 94 (23%) versus 0 of 53 (0%); p < 0.001 and 33 of 78 (42%) versus 13 of 53 (25%), p = 0.04 for the balloon angioplasty and stent groups, respectively. At 6 months, the cumulative probability of repeat target lesion revascularization was higher in the balloon angioplasty group (47% vs 18%, p = 0.0006) as was the probability of late target revascularization (36% vs 18%, p = 0.046); the cumulative event-free survival after 6 months was significantly lower in the balloon angioplasty group (44% vs 80%, p = 0.0001). This study demonstrates that a primary stent placement strategy in patients with AMI is safe, feasible, and superior to primary balloon angioplasty with stent bailout. Primary stenting results in a larger postprocedural minimal luminal diameter, a lower early and late recurrent ischemic event rate, and a lower incidence of target lesion revascularization at follow-up.

Behavior of atherosclerotic plaque components after in vitro angioplasty and atherectomy studied by high field MR imaging

AIMS

Using magnetic resonance imaging (MRI), we developed in vitro models to image the response of fatty, fibrous, and calcified plaques to in vitro models of angioplasty and atherectomy, and tested the resistance of collagenous cap and lipid core to radial compression.

METHODS AND RESULTS

We studied the effects of balloon compression on 10 fibrous plaques with a complete collagenous cap (group A), 6 fatty plaques without cap (group B), and 5 calcified plaques (group C). Atherectomy was performed on nine other fibrous lesions (group D). In group A, fibrous cap, lipid core, and plaque did not change after radial compression despite a decrease in luminal obstruction due to medial stretching. In group B, a reduction of plaque (-30%) and lipid core (-35%) were observed. Compression dissected calcified plaques at the shoulder level. In group D, atherectomy reduced collagenous cap by 54%, and plaque by 35%.

CONCLUSIONS

In these models, MRI shows 1) the high resistance of collagenous caps to radial compression, 2) a stretching effect of compression on disease-free walls, enlarging lumen in case of fibrous plaque, but a reduction and redistribution of lipid cores in case of fatty plaques, 3) the rupture of calcified arteries at the plaque shoulder, and 4) the reduction of fibrous components by atherectomy but not by angioplasty. By characterizing plaque composition, MRI may allow a predictable response of atherosclerotic arteries to interventional procedures.

Human 4-1BB (CD137) signals are mediated by TRAF2 and activate nuclear factor-kappa B

Human 4-1BB (CD137), a member of the tumor necrosis factor receptor (TNFR) superfamily, costimulates T cell activation. No apparent intrinsic kinase activity is seen with 4-1BB, which suggests that 4-1BB-associated molecules may be involved in 4-1BB-mediated signal transduction. We found that tumor necrosis factor receptor-associated factor (TRAF) 1, TRAF2, and TRAF3, all interacted with the cytoplasmic domain of 4-1BB. Mutation analysis showed that TRAF1, TRAF2, and TRAF3 were associated with one of two runs of acidic residues found in the cytoplasmic domain of 4-1BB. In addition, 4-1BB cross-linking with TCR signal in Jurkat cells and overexpression of 4-1BB in 293 cells were able to induce activation of the nuclear factor-kappa B (NF-kappa B). 4-1BB-mediated NF-kappa B activation was inhibited by a dominant negative-TRAF2 or -NF-kappa B-inducing kinase (NIK). These data suggest that 4-1BB functions may be mediated by NF-kappa B activation, which requires a TRAF2/NIK pathway.

Alpha 2-antiplasmin causes thrombi to resist fibrinolysis induced by tissue plasminogen activator in experimental pulmonary embolism

BACKGROUND

In patients with pulmonary embolism, thrombi resist fibrinolysis induced by plasminogen activators. Because the molecular basis of this thrombus resistance is poorly understood, we used a potent inhibitor to examine the potential role of alpha 2-antiplasmin (alpha 2AP) in experimental pulmonary embolism.

METHODS AND RESULTS

Lysis of experimental pulmonary emboli was measured 4 hours after embolization in anesthetized ferrets. All animals received heparin (100 U/kg). Five experimental groups were studied: (1) no recombinant tissue plasminogen activator (rTPA); (2) rTPA at 1 mg/kg; (3) rTPA at 2 mg/kg; (4) rTPA at 1 mg/kg plus a control monoclonal antibody (MAb); and (5) rTPA at 1 mg/kg plus an alpha 2AP inhibitor (MAb 77A3). In comparison with ferrets receiving no rTPA (15.6 +/- 10.5% lysis, mean +/- SD), rTPA-treated groups showed significantly greater lysis (P < .01). Animals treated with rTPA and alpha 2AP inhibitor (56.2 +/- 4.7% lysis) showed significantly greater lysis than all other treatment groups, including ferrets treated with the same dose of rTPA alone (38.5 +/- 6.3%, P < .01), with twice the rTPA dose alone (45.0 +/- 6.5%, P < .05), or with a control MAb (35.2 +/- 4.6%, P < .01). The combination of rTPA treatment and alpha 2AP inhibition caused no consumption of fibrinogen.

CONCLUSIONS

Inhibition of alpha 2AP significantly amplified the lysis of experimental pulmonary emboli by rTPA without increasing fibrinogen consumption. These results suggest that alpha 2AP may play an important role in thrombus resistance in patients with venous thromboembolism.

Variability of platelet degranulation by different contrast media

RATIONALE AND OBJECTIVES

It has been suggested that nonionic but not ionic contrast media degranulate blood platelets when mixtures of blood and contrast media are studied by flow cytometry. This phenomenon was further assessed in the current study not only by performing whole-blood platelet flow cytometry but also by performing flowing blood platelet aggregometry. The latter is a highly sensitive measure of platelet function.

METHODS

Blood samples were collected from six normal donors and mixed with equal volumes of an ionic monomer (diatrizoate), a nonionic monomer (iohexol), an ionic dimer (ioxaglate), and a nonionic dimer (iodixanol). Samples were collected in the presence of no anticoagulant for 1 min prior to the addition of sodium citrate or in the presence of heparin (14.5 U/ml) or recombinant hirudin (60 micrograms/ml). All samples were fixed in formaldehyde within 30 min.

RESULTS

Platelet degranulation was observed with one nonionic agent (iohexol) and one ionic agent (diatrizoate). Degranulation was not seen with iodixanol or ioxaglate.

CONCLUSION

These findings indicate that degranulation is independent of the ionic or nonionic nature per se of contrast media. A possible explanation for this conclusion is suggested.

Transient thrombotic state after abrupt discontinuation of heparin in percutaneous coronary angioplasty

Clinical and biochemical evidence of a rebound phenomenon after discontinuing thrombin inhibitors has been reported in patients with unstable angina. To investigate if a similar phenomenon occurs in patients undergoing coronary angioplasty, 14 patients were prospectively studied during and after discontinuation of heparin infusion. A transient thrombotic state identified by a significant increase in a polypeptide fragment and fibrinopeptide A was observed 3 hours after abruptly discontinuing heparin infusion. This observation may be clinically important in managing patients after coronary angioplasty.

Morphologic characteristics of restenotic lesions following coronary interventions: balloon angioplasty versus directional atherectomy: can we speculate about the mechanism of restenosis from morphologic analysis?

In order to compare the processes of restenosis after balloon angioplasty as compared to that after directional coronary atherectomy, we performed qualitative and quantitative analysis of 72 lesions in 68 patients with recurrent ischemia following a successful initial procedure. For each lesion, we reviewed the pre-intervention, immediate post-intervention, and restenosis angiograms. The morphology of the restenotic lesions could not be predicted from pre- or post-intervention angiograms. The restenotic lesions after directional atherectomy, as compared to balloon angioplasty, did not show a statistically significant difference, although there was a trend to more eccentric narrowing.

A novel chemokine, macrophage inflammatory protein-related protein-2, inhibits colony formation of bone marrow myeloid progenitors

A new member of the beta-chemokine family, macrophage inflammatory protein (MIP)-related protein-2 (MRP-2) was isolated from a murine macrophage cell line, RAW 264.7. MRP-2 is composed of 122 amino acids of which the first 21 residues constitute a putative signal sequence. The putative mature protein is composed of 101 amino acids with a molecular weight of 11,600. MRP-2 is structurally similar to MIP-related protein-1 (MRP-1) (C10) and MIP-1 alpha. MRP-2 shows a 50.8% sequence identity at the protein level to MRP-1 and 46.3% identity to MIP-1 alpha. MRP-2 detects approximately 1.3 kilobase mRNA from monocyte and macrophage cell lines but does not detect the mRNA from T and B cells. The MRP-2 gene termed Scya9 was mapped to the central region of mouse chromosome 11 near the Scya1 and Scya2 genes, which are also members of the beta-chemokine superfamily. The Scya gene cluster was located between neurofibromatosis type 1 (Nf1) and myeloperoxidase (Mpo). rMRP-2 significantly suppressed colony formation by murine and human bone marrow granulocyte-macrophage (CFU-granulocyte-macrophage), erythroid (burst-forming unit-E), and multipotential (CFU-granulocyte-erythroid-macrophage-megakaryocyte) progenitor cells stimulated by combinations of growth factors.

A novel chemokine, macrophage inflammatory protein-related protein-2, inhibits colony formation of bone marrow myeloid progenitors

A new member of the beta-chemokine family, macrophage inflammatory protein (MIP)-related protein-2 (MRP-2) was isolated from a murine macrophage cell line, RAW 264.7. MRP-2 is composed of 122 amino acids of which the first 21 residues constitute a putative signal sequence. The putative mature protein is composed of 101 amino acids with a molecular weight of 11,600. MRP-2 is structurally similar to MIP-related protein-1 (MRP-1) (C10) and MIP-1 alpha. MRP-2 shows a 50.8% sequence identity at the protein level to MRP-1 and 46.3% identity to MIP-1 alpha. MRP-2 detects approximately 1.3 kilobase mRNA from monocyte and macrophage cell lines but does not detect the mRNA from T and B cells. The MRP-2 gene termed Scya9 was mapped to the central region of mouse chromosome 11 near the Scya1 and Scya2 genes, which are also members of the beta-chemokine superfamily. The Scya gene cluster was located between neurofibromatosis type 1 (Nf1) and myeloperoxidase (Mpo). rMRP-2 significantly suppressed colony formation by murine and human bone marrow granulocyte-macrophage (CFU-granulocyte-macrophage), erythroid (burst-forming unit-E), and multipotential (CFU-granulocyte-erythroid-macrophage-megakaryocyte) progenitor cells stimulated by combinations of growth factors.

Percutaneous mitral balloon valvotomy for recurrent mitral stenosis after surgical commissurotomy

Immediate outcome and 4-year follow-up results of percutaneous mitral balloon valvotomy (PMV) in patients with previous surgical mitral commissurotomy are studied. Repeat surgical mitral commissurotomy in patients with previous surgical commissurotomy is associated with higher mortality and morbidity. PMV has been proven to be safe and could be an ideal alternative in this patient group. The results of 68 patients with previous surgical commissurotomy were compared with those of 261 patients without prior surgical intervention. A good outcome, defined as the final mitral valve area > 1.5 cm2, was obtained in 51% of the patients with prior surgical commissurotomy compared with 71% in the control group (p = 0.002). During the 4-year follow-up period, there were more patients who required mitral valve replacement (19% vs 7%; p = 0.004) and who were in New York Heart Association functional class III and IV (85% vs 71%; p = 0.02) among those with prior surgical commissurotomy. However, when these patients were divided according to echocardiographic score, those with a score < or = 8 had immediate outcome and long-term results similar to those without prior commissurotomy. PMV can be performed safely in patients with prior surgical commissurotomy. Although results of long-term follow-up in these patients is not as good as those in patients without prior surgical commissurotomy, those with a low echocardiographic score had similar excellent long-term results.