Interdisciplinary consensus on indications for transfemoral transcatheter aortic valve implantation (TF-TAVI) : Joint Consensus Document of the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte e.V. (ALKK) and cooperating Cardiac Surgery Departments.

Indications for TF-TAVI (transfemoral transcatheter aortic valve implantation) are rapidly changing according to increasing evidence from randomized controlled trials. Present trials document the non-inferiority or even superiority of TF-TAVI in intermediate-risk patients (STS-Score 4-8%) as well as in low-risk patients (STS-Score < 4%). However, risk scores exhibit limitations and, as a single criterion, are unable to establish an appropriate indication of TF-TAVI vs transapical TAVI vs SAVR (surgical aortic valve replacement). The ESC (European Society of Cardiology)/EACTS (European Association for Cardio-Thoracic Surgery) guidelines 2017 and the German DGK (Deutsche Gesellschaft für Kardiologie)/DGTHG (Deutsche Gesellschaft für Thorax-, Herz- und Gefäßchirurgie) commentary 2018 offer a framework for the selection of the best therapeutic method, but the individual decision is left to the discretion of the heart teams. An interdisciplinary TAVI consensus group of interventional cardiologists of the ALKK (Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte e.V.) and cardiac surgeons has developed a detailed consensus on the indications for TF-TAVI to provide an up-to-date, evidence-based, comprehensive decision matrix for daily practice. The matrix of indication criteria includes age, risk scores, contraindications against SAVR (e.g., porcelain aorta), cardiovascular criteria pro TAVI, additional criteria pro TAVI (e.g., frailty, comorbidities, organ dysfunction), contraindications against TAVI (e.g., endocarditis) and cardiovascular criteria pro SAVR (e.g., bicuspid valve anatomy). This interdisciplinary consensus may provide orientation to heart teams for individual TAVI-indication decisions. Future adaptations according to evolving medical evidence are to be expected. Interdisciplinary consensus on indications for transfemoral transcatheter aortic valve implantation (TF-TAVI).

Construction and characterization of a recombinant plasminogen activator composed of an anti-fibrin single-chain antibody and low-molecular-weight urokinase.

BACKGROUND: Targeting of plasminogen activators to the fibrin component of a thrombus by antibodies directed against human fibrin can enhance their thrombolytic potency and clot specificity. OBJECTIVES: To overcome the disadvantages of chemical conjugation, we investigated whether the recombinant fusion of a single-chain antibody and a plasminogen activator results in an active bifunctional molecule that might be useful as a therapeutic agent. METHODS: The cDNA of low-molecular-weight single-chain urokinase-type plasminogen activator, comprising amino acids Leu144-Leu411 (scuPA(LMW)), was cloned from human endothelial cells and fused to a single-chain antibody specific for the 7 N-terminal amino acids (beta(15-22)) in the beta-chain of human fibrin (scFv(59D8)). The fusion protein was purified using affinity chromatography with the beta(15-22)-peptide of human fibrin. RESULTS: Purified scFv(59D8)-scuPA(LMW) migrated as a 60-kDa band, which is consistent with a molecule composed of one scFv(59D8) and one scuPA(LMW) moiety. Both functions of the fusion molecule, fibrin-specific binding and plasminogen activation, were fully preserved. In human plasma clots, thrombolysis by scFv(59D8)-scuPA(LMW) is significantly faster and more potent compared with the clinically used urokinase. CONCLUSIONS: ScFv(59D8)-scuPA(LMW) constitutes a new recombinant chimeric plasminogen activator with a significantly enhanced thrombolytic potency and relative fibrin selectivity, that can be produced with modern methods at low cost, large quantities and reproducible activity in Escherichia coli.

Ecarin clotting time but not aPTT correlates with PEG-hirudin plasma activity.

BACKGROUND: Novel antithrombotic agents such as hirudin have shown promise in the therapy of acute coronary syndromes. PEG-hirudin (polyethyleneglycol conjugated hirudin) has been developed to provide a longer plasma half-life and more stable antithrombotic plasma levels. Privious trials indicated a narrow therapeutic window for hirudin and a number of aPTT (activated partial thromboplastin time)-monitored trials investigating hirudin in acute coronary syndromes had to be stopped because of intracranial bleeding complications. OBJECTIVES: The present study evaluates the ecarin clotting time (ECT), a parameter based on the conversion of prothrombin by the snake venom enzyme ecarin, for the monitoring of PEG-hirudin therapy. METHODS: Plasma from either healthy volunteers (n=20) or from patients (n=10) suffering from unstable angina pectoris (UAP) was spiked with increasing PEG-hirudin concentrations. In a prospective randomized clinical trial patients with UAP were treated with intravenous PEG-hirudin or heparin over 72 hours. Patients were randomized to the following treatment groups: (1) heparin control group, n=15; (2) PEG-hirudin low dose (0.1 mg/kg bolus, 0.01 mg/kg/h infusion), n=19; (3) intermediate dose (0.15 mg/kg and 0.015 mg/kg/h), n=17; 4) high-dose (0.2 mg/kg and 0.02 mg/kg/h), n=16. Spiked plasma samples and plasma from UAP patients treated with i.v. PEG-hirudin were analyzed for aPTT, ECT, and PEG-hirudin levels. RESULTS: A linear correlation up to the highest therapeutic concentrations could be observed between PEG-hirudin plasma concentrations and the ECT. This was true for both plasma samples spiked with PEG-hirudin in vitro as well as for samples taken from patients treated with i.v. PEG-hirudin (correlation coefficient 0.9, respect.) In contrast the aPTT did not show a reliable linear correlation to PEG-hirudin concentrations. CONCLUSION: Monitoring of PEG-hirudin therapy by ECT may help to avoid inadequate anticoagulation or overdosing. Thus, the safety and efficacy profile of PEG-hirudin therapy is likely to be enhanced by ECT monitoring.

Stimulation in vivo of expression of intra-abdominal adipose tissue plasminogen activator inhibitor Type I by proinsulin.

AIMS/HYPOTHESIS: Impaired fibrinolytic system capacity secondary to increased plasminogen activator inhibitor type-1 expression has been suggested as a pathogenetic link between insulin resistance and increased cardiovascular risk in patients with Type II (non-insulin-dependent) diabetes mellitus, obesity, or both. In patients with syndromes of insulin resistance including those with Type II diabetes, precursors of insulin such as proinsulin can constitute more than 50% of insulin-like molecules in blood. The aim of this study was to determine whether proinsulin can increase plasminogen activator inhibitor type-1 expression in intra-abdominal adipose tissue in vivo, potentially contributing to the increased PAI-1 seen with insulin resistance. METHODS: Lightly sedated normal rabbits were given intravenous proinsulin, insulin, or vehicle alone under euglycaemic clamp conditions with serial sampling of blood and assessment of PAI-1 expression in visceral fat. RESULTS: Both proinsulin and insulin increased expression of plasminogen activator inhibitor type-1 in intra-abdominal adipose tissue, 5.3-fold (p = 0.006 vs control) and 2.5-fold (p = 0.031 vs control) respectively. PAI-1 inhibitor activity in blood peaked 3 h after administration of each, 5.1-fold, p = 0.020, and 3.4-fold, p = 0.004, respectively but did not change under control conditions. CONCLUSION/INTERPRETATION: Hyperproinsulinaemia can contribute to increased expression of plasminogen activator inhibitor type-1 in intra-abdominal adipose tissue implicated in increasing PAI-1 activity in blood, impaired fibrinolysis, and accelerated atherogenesis typical of Type II diabetes.

Regulation of PAI-1 expression by genetic polymorphisms. Impact on atherogenesis.

Increased expression of plasminogen activator inhibitor type 1 (PAI-1) is now considered as an independent risk factor for cardiovascular disease. Numerous biochemical factors have been found to regulate the expression of PAI-1 gene and the synthesis of PAI-1 protein. In the recent past, polymorphisms in the PAI-1 gene have been identified and their impact on PAI-1 expression has been characterized. This article will review the current knowledge of these PAI-1 gene polymorphisms (in cell culture epidemiological, and clinical studies) and their role in the development of cardiovascular disease.

Intrinsic activating properties of GP IIb/IIIa blockers.

Potential intrinsic activating properties are probably the most controversially discussed issues with respect to GP IIb/IIIa blockers, especially since clinical trials with oral GP IIb/IIIa blockers revealed disappointing results. Based on the finding that currently clinically used GP IIb/IIIa blockers are ligand mimetics, experimental data are discussed, demonstrating an intrinsic activating effect of ligand mimetic GP IIb/IIIa blockers that potentially results in fibrinogen binding to alpha(IIb)beta(3) and in platelet aggregation. Furthermore, the inhibitory effect of aspirin on GP IIb/IIIa blocker-induced platelet aggregation is discussed as a clinically relevant finding. Finally, the potential association of GP IIb/IIIa blocker-induced thrombocytopenia with platelet activation is described.

[Optimal thrombolysis]. / Optimale Thrombolyse.

Thrombolytic therapy is an established reperfusion strategy in acute myocardial infarction with proven long-term survival benefit. New thrombolytic agents including reteplase, lanoteplase, and tenecteplase have been developed to optimize thrombolytic therapy. With respect to efficacy the new thrombolytic agents show mortality equivalent to front-loaded alteplase, the present gold standard of thrombolytic therapy. With respect to ease of application there are advantages because third generation agents can be given as a single or double bolus instead of a bolus followed by an infusion. The most promising strategy to optimize coronary thrombolysis seems to be the combination of thrombolytic agents in reduced dose and GP IIb/IIIa blockers in full dose. The corresponding clinical trials (TIMI-14, SPEED, and INTRO-AMI) have also shown that there is an evolution in the surrogate end points for an optimal thrombolysis. In the past, optimal thrombolysis was associated with an open infarct-related coronary artery. A few years ago it was realized that TIMI-3 flow in the epicardial coronary artery was associated with the best results. Presently, normal myocardial microcirculation is regarded an additional prerequisite for further reduced mortality in acute myocardial infarction.

[GPIIb/IIIa blockers for optimizing thrombolysis in acute myocardial infarct]. / GPIIb/IIIa-Blockade zur Optimierung der Thrombolyse bei akutem Myokardinfarkt.

BACKGROUND: Thrombolytic therapy is an established strategy for the treatment of acute myocardial infarction. GPIIB/IIIA BLOCKERS + MODERN THROMBOLYTIC AGENTS: At present, the most attractive development for optimizing thrombolytic therapy includes the use of GPIIb/IIIa blockers in combination with modern thrombolytic agents such as alteplase and reteplase. The review summarizes the available results of clinical studies using standard doses of thrombolytic agents (TAMI 8, IMPACT-AMI, and PARADIGM) or reduced dosages of thrombolytic agents (TIMI 14 and SPEED) for combination therapy. The review also focuses on the implications of the combination therapy for coronary angioplasty immediately following coronary thrombolysis.

Attenuation by fibrates of plasminogen activator inhibitor type-1 expression in human arterial smooth muscle cells.

Human atherosclerotic lesions exhibit increased expression of plasminogen activator inhibitor type-1 (PAI-1) that has been implicated in atherogenesis. Although vascular smooth muscle cells are a predominant source of PAI-1 expression potentially favorable modulation of PAI-1 expression by fibrates has not yet been characterized in these cells. Human aortic smooth muscle cells were exposed to selected growth factors. PAI-1 expression was stimulated most powerfully by TGF-beta (EC50 = 0.2 ng/ml, up to 12-fold increase). Gemfibrozil inhibited basal PAI-1 expression by 23% (p = ns) and TGF-beta-induced PAI-1 expression by 52% (p = 0.017) whereas t-PA and total protein synthesis was not affected. Changes in PAI-1 protein accumulation reflected PAI-1 gene expression attributable to modulation of half-life of PAI-1 mRNA by gemfibrozil. Inhibition by other fibrates was less. Gemfibrozil specifically attenuates TGF-beta-induced PAI-1 expression in human arterial smooth muscle cells. Thus, fibrates are promising agents for normalizing increased PAI-1 expression in arterial walls in patients in whom PAI-1 expression is increased.

[Therapeutic inhibition of platelets in a acute coronary syndrome and in coronary intervention: mechanisms and clinical results]. / Therapeutische Inhibition von Thrombozyten im akuten Koronarsyndrom und bei Koronarintervention: Mechanismen und klinische Ergebnisse.

Platelets play a crucial role in the pathogenesis of atherosclerosis and especially in the final ischemic consequences such as acute coronary syndromes. Furthermore, platelets are central mediators of acute or subacute complications of coronary interventions. Therefore, therapeutic inhibition of platelet function is of major interest in cardiology. The following review describes three different therapeutic strategies for platelet inhibition and provides a representative overview on the clinical results of studies based on these strategies. First, the mechanism of acetylsalicylic acid is described and the strong meta-analytic data demonstrating a convincing positive clinical effect is discussed. Second, the mode of action of the thienopyridines is described and initial clinical results are discussed. Third, the inhibition of the platelet integrin receptor GP IIb/IIIa is described as a potent way to block the final common pathway of platelet stimulation. The structural description of GP IIb/IIIa is followed by a structural classification of the available GP IIb/IIIa inhibitors. Clinical studies, meanwhile including several thousands of patients, are discussed based on representative examples. Finally, unresolved issues regarding the various GP IIb/IIIa inhibitors, such as differences in receptor affinity and specificity, intrinsic activation and GP IIb/IIIa inhibitor induced thrombocytopenia are, discussed.

Impaired endogenous fibrinolysis in diabetes mellitus: mechanisms and therapeutic approaches.

In type II diabetes mellitus the activity of the endogenous fibrinolytic system is reduced secondary to increased plasma activity of the plasminogen activator inhibitor type 1 (PAI-1). Because PAI-1 is considered an independent risk factor for cardiovascular disease, increased PAI-1 activity in diabetes mellitus may partly explain the increased susceptibility to both primary atherosclerosis and restenosis after angioplasty in this disease. The factors contributing to increased PAI-1 expression in diabetes mellitus are reviewed as well as possible therapeutic approaches to normalize increased PAI-1 expression.

Flow cytometric monitoring of glycoprotein IIb/IIIa blockade and platelet function in patients with acute myocardial infarction receiving reteplase, abciximab, and ticlopidine: continuous platelet inhibition by the combination of abciximab and ticlopidine.

BACKGROUND: Improvement of thrombolysis may be achieved by concomitant strong platelet inhibition. To monitor platelet function in patients with myocardial infarction (n=46) who were treated with the fibrinolytic agent reteplase, the glycoprotein (GP) IIb/IIIa blocker abciximab, and the ADP receptor antagonist ticlopidine, we developed a flow cytometric assay. METHODS AND RESULTS: Binding of abciximab to platelets was directly monitored as the percentage of platelets stained by a goat anti-mouse antibody. Blood drawn 10 minutes and 2 hours after the start of therapy with reteplase and abciximab and during the 12-hour infusion of abciximab demonstrated a maximal blockade of GP IIb/IIIa (10 minutes, 86.2+/-10.3%; 12 hours, 85.8+/-7.1%). Starting at 24 hours, abciximab binding gradually decreased (24 hours, 74.6+/-16.2%; 48 hours, 66.8+/-14.9%; 72 hours, 60.5+/-16.7%; 96 hours, 49.4+/-17.8%; 120 hours, 35.8+/-16. 4%; and 144 hours, 29.9+/-15.3%). Binding of a chicken anti-fibrinogen antibody to platelets, indicating the level of functional blockade of GP IIb/IIIa, was inversely correlated with the binding of abciximab (r=-0.72, P:<0.0001). In blood drawn at 10 minutes, platelet aggregation was maximally inhibited but recovered within 48 hours even if the majority of GP IIb/IIIa receptors were still blocked by abciximab. Reteplase did not influence abciximab binding and did not activate platelets, as measured by P-selectin expression, fibrinogen binding, and platelet aggregation. Platelet inhibition that was achieved during the first 24 hours by abciximab was directly maintained by additional treatment with ticlopidine. CONCLUSIONS: Flow cytometric monitoring of platelet function allows differentiation of the effects of reteplase, abciximab, and ticlopidine. The combination of abciximab and ticlopidine is an attractive therapeutic strategy that provides a fast and continuous platelet inhibition.

[Endothelium and endogenous fibrinolysis]. / Endothel und endogene Fibrinolyse.

Reduced activity of the endogenous fibrinolytic system contributes to intramural deposition of microthrombi in atherogenesis and to intraluminal deposition of thrombi leading to acute complications of atherosclerosis such as acute coronary syndromes. Endogenous fibrinolytic activity is predominantly regulated by the plasminogen activator inhibitor type 1 (PAI-1). Increased activity of PAI-1 leading to reduced endogenous fibrinolytic activity has been identified as an important independent risk factor for cardiovascular disease. Vascular endothelial cells form a barrier between the circulating blood with its dynamic balance between ongoing thrombosis and fibrinolysis and the subendothelial layers of the vascular wall with their prothrombotic activity. In addition, endothelial cells synthesize and secrete substantial amounts of plasminogen activators and their inhibitor PAI-1. Thus, endothelium plays an important role in the regulation of endogenous fibrinolysis. After describing the components of the endogenous fibrinolytic system and its interactions, this review focuses on the impact on endogenous fibrinolysis by the renin angiotensin system, the kallikrein kinin system, and type 2 diabetes mellitus. Investigations using transgenic and knock-out animal models--the results of which are also summarized--have improved our understanding of the interaction between endogenous fibrinolysis and endothelium. In each section of the review therapeutic implications and potentials are discussed.

Differential regulation by troglitazone of plasminogen activator inhibitor type 1 in human hepatic and vascular cells.

Troglitazone, a novel oral insulin sensitizer, normalizes increased plasma activity of plasminogen activator inhibitor type 1 (PAI-1) in hyperinsulinemic patients such as women with polycystic ovary syndrome and patients with type 2 diabetes mellitus. However, underlying mechanisms have not yet been fully elucidated. Human hepatic and vascular cells, the main sources of circulating PAI-1, were studied in cell culture. In human hepatic cells, PAI-1 accumulated in conditioned medium by 23% within 24 h after exposure to 3 microg/mL troglitazone (P = 0.001). The accumulation depended on the concentration of troglitazone, but not that of insulin (known to stimulate PAI-1 synthesis). By contrast, in human aortic smooth muscle cells, 3 microg/mL troglitazone decreased basal PAI-1 expression by 23% (P = 0.037) and decreased transforming growth factor-beta-induced expression by 34% (P = 0.026). Concomitant insulin had no effect. Tissue-type plasminogen activator was decreased by 38% (P = 0.002). In human endothelial cells, PAI-1 was diminished by 32% (P < 0.001), whereas tissue-type plasminogen activator was unaffected. The results suggest that the reduction in plasma activity of PAI-1 induced by troglitazone in patients may reflect both directly mediated diminution of its elaboration from vessel walls and indirectly mediated reduction of its hepatic synthesis secondary to attenuation of hyperinsulinemia (known to increase the hepatic synthesis of PAI-1).

[Therapeutic inhibition of platelets in acute coronary syndrome and in coronary intervention: mechanisms and clinical results]. / Therapeutische Inhibition von Thrombozyten im akuten Koronarsyndrom und bei Koronarintervention: Mechanismen und klinische Ergebnisse.

Platelets play a crucial role in the pathogenesis of atherosclerosis and especially in the final ischemic consequences such as acute coronary syndromes. Furthermore, platelets are central mediators of acute or subacute complications of coronary interventions. Therefore, therapeutic inhibition of platelet function is of major interest in cardiology. The following review describes three different therapeutic strategies for platelet inhibition and provides a representative overview on the clinical results of studies based on these strategies.First, the mechanism of acetylsalicylicacid is described and the strong metaanalytic data demonstrating a convincing positive clinical effect is discussed. Second, the mode of action of the thienopyridines is described and initial clinical results are discussed. Third, the inhibition of the platelet integrin receptor GP IIb/IIIa is described as a potent way to block the final common pathway of platelet stimulation. The structural description of GP IIb/IIIa is followed by a structural classification of the available GP IIb/IIIa inhibitors. Clinical studies, meanwhile including several thousands of patients, are discussed based on representative examples. Finally, unresolved issues regarding the various GP IIb/IIIa inhibitors, such as differences in receptor affinity and specificity, intrinsic activation and GP IIb/IIIa inhibitor induced thrombocytopenia are, discussed.