von Willebrand factor antigen: a novel on-treatment predictor of response to antiviral therapy in chronic hepatitis C genotypes 1 and 4.

BACKGROUND: Levels of von Willebrand factor antigen (vWF-Ag) increase during combination antiviral therapy of chronic hepatitis C (CHC). The present study investigates the association between these changes in vWF-Ag levels and response to treatment. METHODS: Changes in levels of vWF-Ag on antiviral combination treatment in 184 patients with CHC genotype 1 or 4 infections were measured prospectively and effect on response was studied. RESULTS: High on-treatment levels of vWF-Ag were associated with relapse (P<0.01) and low on-treatment levels with sustained virological response (SVR). Receiver operating characteristic curve analysis showed that vWF-Ag levels of <300% at week 12 of therapy have a positive predictive value (PPV) of 78% for SVR. In early virological response (EVR) patients, the PPV of vWF-Ag levels <300% at week 12 was 74%. An even higher PPV of 88% in complete EVRs (undetectable HCV RNA at week 12) was observed for the same cutoff value at week 12. CONCLUSIONS: On-treatment levels of vWF-Ag can be utilized as an additional predictive marker for response to antiviral therapy. This is especially relevant in EVR patients because EVR alone only has a PPV of 58-72% on SVR, which increased to 74%, when factoring in vWF-Ag levels <300% at week 12, and to 88% in complete EVRs; therefore, measurement of vWF-Ag levels at week 12 is helpful. EVR patients that are above the cutoff values for vWF-Ag that make SVR very probable might profit from an extension of therapy to 72 weeks.

O-glycoside biomarker of apolipoprotein C3: responsiveness to obesity, bariatric surgery, and therapy with metformin, to chronic or severe liver disease and to mortality in severe sepsis and graft vs host disease.

The glyco-isoforms of intact apolipoprotein C3 (ApoC3) were used to probe glycomic changes associated with obesity and recovery following bariatric surgery, liver diseases such as chronic hepatitis C (CHC) and alcoholic liver cirrhosis, as well as severe, multiorgan diseases such as sepsis and graft vs host disease (GVHD). ApoC3 glyco-isoform ratios responded to unique stimuli that did not correlate with serum lipids or with other blood components measured in either a control population or a group of extremely obese individuals. However, glyco-isoform ratios correlated with obesity with a 1.8-fold change among subjects eligible for bariatric surgery relative to a nonobese control population. Bariatric surgery resulted in rapid change of isoform distribution to that of nonobese individuals, after which the distribution was stable in each individual. Although multiple simultaneous factors complicated effector attribution, the isoform ratios of very obese individuals were nearly normal for diabetic individuals on metformin therapy. Glyco-isoform ratios were sensitive to liver diseases such as chronic hepatitis C and alcoholic liver cirrhosis. The correlation coefficient with fibrosis was superior to that of current assays of serum enzyme levels. Diseases of pregnancy that can result in liver damage, HELLP syndrome and pre-eclampsia, did not alter ApoC3 glyco-isoform ratios. Early after umbilical cord blood transplantation the isoform ratios changed and returned to normal in long-term survivors. Larger changes were observed in persons who died. GVHD had little effect. Persons with severe sepsis showed altered ratios. Similar cut-points for mortality (3.5-fold difference from controls) were found for UCBT and sepsis. Similar values characterized liver cirrhosis. Overall, while changes of glyco-isoform ratios occurred in many situations, individual stability of isoform distribution was evident and large changes were limited to high-level disease. If ratio changes associated with obesity are found to document a risk factor for long-term outcomes, the information provided by glyco-isoform ratio changes may provide important, novel information for diagnostic, prognostic and therapy response to metabolic conditions.

Top-down proteomic analysis by MALDI-TOF profiling: Concentration-independent biomarkers.

Although numerous protein biomarkers have been correlated with advanced disease states, no new clinical assays have been developed. Goals often anticipate disease-specific protein changes that exceed values among healthy individuals, a property common to acute phase reactants. This review considers somewhat different approaches. It focuses on intact protein isoform ratios that present a biomarker without change in the total concentration of the protein. These will seldom be detected by peptide level analysis or by most antibody-based assays. For example, application of an inexpensive method to large sample groups resulted in observation of several polymorphisms, including the first structural polymorphism of apolipoprotein C1. Isoform distribution of this protein was altered and was eventually linked to increased obesity. Numerous other protein isoforms included C- and N-terminal proteolysis, changes of glycoisoform ratios and certain types of sulfhydryl oxidation. While many of these gave excellent statistical correlation with advanced disease, clinical utility was not apparent. More important may be that protein isoform ratios were very stable in each individual. Diagnosis by longitudinal analysis of the same individual might increase sensitivity of protein biomarkers by 20-fold or more. Protein changes that exceed the range of values found among healthy individuals may be uncommon.

6-thioguanine associated nodular regenerative hyperplasia in patients with inflammatory bowel disease may induce portal hypertension.

BACKGROUND: Recent studies suggest an association between 6-thioguanine (6-TG) therapy and hepatic nodular regenerative hyperplasia (NRH) in patients with inflammatory bowel disease (IBD). An influence of 6-TG on portal pressure remains to be determined. The aim of the study was to examine the functional relevance of long-term 6-TG treatment on hepatic hemodynamics in IBD patients and its association with NRH. METHODS: Patients treated with 6-TG for IBD underwent measurement of the hepatic venous pressure gradient (HVPG) and liver biopsy. 6-TG therapy was stopped when NRH was diagnosed. If elevated, HVPG measurement was repeated after 1 yr. RESULTS: Twenty-six patients (15 women, 11 men; median age 41 yr, range 23-76) treated with 6-TG for 38 months (median; range 12-45) were included. Among 24 patients with sufficient liver biopsy, 6 patients (25%) were diagnosed with NRH. In these 6 patients, the HVPG was higher (median HVPG 7 mmHg, range 3-14) than in the 18 patients without NRH (median 3 mmHg, range 2-5; P < 0.001). In the patients with NRH, two had clinically significant portal hypertension (CSPH) (13 and 14 mmHg, respectively); in one patient the HVPG was slightly elevated (7 mmHg). No overt clinical signs of portal hypertension were observed. One year after stopping 6-TG therapy, HVPG decreased in all 3 patients with initially elevated HVPG levels. CONCLUSIONS: We demonstrate that IBD patients under long-term 6-TG therapy are at a substantial risk for developing NRH. NRH results in elevation of HVPG and may cause CSPH. Discontinuation of 6-TG therapy extenuates portal hypertension and may thus reduce the risk of complications.

WITHDRAWN: Extraordinary apolipoprotein oxidation in chronic hepatitis C and liver cirrhosis.

Withdrawn by Author.

Altered platelet plug formation in hyperthyroidism and hypothyroidism.

OBJECTIVE: Patients with thyroid diseases have abnormalities of blood coagulation including an alteration of von Willebrand factor (vWF) levels. Because vWF plays an important role in primary hemostasis, we hypothesized that heightened and decreased vWF levels in hyper- and hypothyroidism enhance and decrease platelet plug formation, respectively. METHODS: We followed a cohort of 120 patients with overt hyperthyroidism, patients with subclinical and overt hypothyroidism, and euthyroid controls. vWF and in vitro platelet plug formation as collagen-epinephrine-induced closure time (CEPI-CT) were measured at baseline and during therapy with thiamazole or T(4). RESULTS: Baseline vWF levels were higher in patients with hyperthyroidism and lower in patients with overt hypothyroidism than in controls (P < 0.01). High vWF antigen levels were associated with increased baseline platelet plug formation in patients with hyperthyroidism as compared with controls [114 sec (95% confidence interval, 105-122 sec) vs. 130 sec (120-140 sec), P = 0.01]. After 8 wk of therapy with thiamazole, serum concentrations of T(4) and vWF levels decreased to normal values (P < 0.01 vs. baseline), and CEPI-CT was prolonged as compared with baseline (P < 0.01). During therapy with T(4), vWF levels increased (P < 0.05 vs. baseline) and CEPI-CT was shortened as compared with baseline (P < 0.01). CONCLUSION: Hyperthyroidism-induced vWF elevation is associated with enhanced platelet function and therefore shortened CEPI-CT values. These changes may contribute to the higher risk for cardiovascular disease in patients with hyperthyroidism. Platelet plug formation decreases during therapy with thiamazole. Furthermore, CEPI-CT appears to be sensitive to detect acquired von Willebrand disease associated with overt hypothyroidism.

Prescintigraphic morphine application for abdominal adenocarcinoma imaging, with technetium-99m methoxy isobutyl isonitrile.

Imaging of tumors with cationic tracers, especially with technetium-99 methoxy isobutyl isonitrile ((99m)Tc-MIBI), revealed high specificity for the diagnosis and follow up of various malignancies. However, these radiopharmaceuticals are of limited value for the diagnosis of malignancies of the abdominal region due to the immediate biliary secretion of the tracer and the associated high background activity. In a prospective, single-blinded protocol, patients with endoscopically diagnosed gastrointestinal malignancies were assigned to undergo (99m)Tc-MIBI imaging of the abdomen. To overcome biliary secretion of cationic tracer we administered 0.04 mg/kg morphine hydrochloride intravenously before the administration of 600 MBq (99m)Tc-MIBI. Planar images were performed in the anterior and posterior views with a double-headed gamma camera and with 3 min acquisition time, followed by single photon emission tomography images (3 degrees, 20 sec/frame). Results were compared to findings of endoscopy, computed tomography scan and surgery. Twenty four patients 17 male and 7 female , mean age 69 years, range 52-83, years were enrolled. All patients suffered from adenocarcinoma, (19 from colorectum, 3 from gastric, 1 from pancreatic and one patient had both gastric and colorectal adenocarcinoma, for a total of 25 tumor lesions). The primary objective- inhibition of biliary secretion- was achieved in 23 of the 24 patients. (99m)Tc-MIBI-imaging was accumulated intra-abdominally in 19 patients. In 2 patients the tumor was endoscopically completely removed before the scan. In these two patients (99m)Tc-MIBI imaging showed no intra-abdominal tracer accumulation. When compared to the endoscopic findings, (99m)Tc-MIBI imaging showed time positive results in 13 of the 23 remaining individual tumor lesions, false positive in 6 and false negative in 4. This study showed a sensitivity of 57% and a specificity of 20% of the above technique for the identification of intra-abnominal adenocarcinomas. Correct diagnosis did not correlate with tumor size. In conclusion, prescintigraphic morphine administration inhibits background activity coming from biliary secretion, and enables better intra-abdominal (99m)Tc-MIBI imaging but with limited sensitivity and poor specificity.

Erythropoietin treatment is associated with more severe thrombocytopenia in patients with chronic hepatitis C undergoing antiviral therapy.

BACKGROUND: Erythropoietin (EPO) not only stimulates erythropoiesis but also thrombopoiesis. As pegylated-interferon-alpha(PEG-IFN-alpha)-induced thrombocytopenia may become a limiting factor for continuation of therapy, the present study investigated if EPO can alleviate PEG-IFN-alpha induced thrombocytopenia. Further, we hypothesize that EPO increases platelet reactivity and protease activated receptor 1 (PAR-1) expression during combination antiviral therapy. METHODS: Forty patients with chronic hepatitis C received either 10,000 IU EPO 3 x/week or placebo in a randomized, placebo-controlled, double-blinded fashion for 4 wk and combination antiviral therapy with PEG-IFN-2a and ribavirin. RESULTS: EPO alleviated the decrease in hemoglobin during combination antiviral therapy with ribavirin (10%vs 20%, p < 0.0001). Platelet counts decreased stronger in EPO than in placebo group on day 28 (p= 0.007). EPO induced a 40% increase in PAR-1 (p < 0.0001), which was accompanied by 100% increase in platelet reactivity (p < 0.0001). PFA-100 platelet plug formation time and PEG-IFN-alpha-induced vWF-increase were not different between study groups. CONCLUSIONS: Treatment with EPO alleviated the decrease in hemoglobin but worsened PEG-IFN-alpha induced thrombocytopenia after the first 4 wk of combination therapy. EPO caused PAR-1 receptor upregulation on platelets, which promoted an increase in platelet reactivity without affecting PFA-100 platelet plug formation time. EPO is not a useful option for short-term support of platelet production during antiviral therapy.

Antiviral therapy decreases GpIIb/IIIa activation of platelets in patients with chronic hepatitis C.

Interferon alpha (IFN-alpha) is used to treat haematological and solid malignancies and is the gold standard therapy for chronic hepatitis C infection in combination with ribavirin. It has a well known platelet lowering effect and was recently shown to impair platelet aggregation in the presence of various agonists and has been accused to increase patients' bleeding risk during IFN-alpha therapy. Thus, we hypothesised that antiviral treatment decreases GpIIb/IIIa activation and affects global platelet function. In a prospective clinical trial, we examined the effects of combination therapy with pegylated IFN-alpha 2a (PegIFN-alpha 2a) and ribavirin on platelet GpIIb/IIIa activation and platelet secretion in 20 patients with chronic hepatitis C at week 2, 4, 8 and 12 after the beginning of therapy. In addition, we determined global platelet function (CEPI-CT) with the PFA-100 and vWF-Ag levels. Antiviral therapy significantly decreased GpIIb/IIIa activation in a time dependent manner, whereas markers of platelet secretion (P-selectin, beta-thromboglobulin) remained unchanged. Despite a marked elevation of vWF-Ag levels, CEPI-CT did not change compared to baseline levels. Antiviral therapy significantly decreases GpIIb/IIIa activation in patients with chronic hepatitis C, while vWG-Antigen levels are markedly increased and alpha-granule secretion is not affected. This does not result in an alteration of global platelet function as assessed by the PFA-100, because elevated vWF-Antigen levels might compensate for the acquired defect.

Vasoconstrictor hyporeactivity can be reversed by antioxidants in patients with advanced alcoholic cirrhosis of the liver and ascites.

OBJECTIVE: Hyperdynamic circulation and systemic vasodilation complicate cirrhosis of the liver and are related to vasoconstrictor hyporeactivity. We investigated whether impaired vasoconstrictor responsiveness may be overcome by antioxidants in patients with decompensated alcoholic cirrhosis. DESIGN: Controlled clinical study. SETTING: University setting. PATIENTS: Nine patients with liver cirrhosis Child-Pugh grade C and nine healthy age-matched volunteers. INTERVENTIONS: Forearm blood flow responses to intra-arterial norepinephrine, angiotensin II, and the nitric oxide synthase inhibitor N-monomethyl-l-arginine were measured by strain-gauge plethysmography and compared between groups of patients. To assess the role of oxidative stress, the antioxidant vitamin C (24 mg/min) was administered locally into the brachial artery, and forearm blood flow responses were reassessed. MEASUREMENTS AND MAIN RESULTS: Plasma concentrations of vitamin C were lower in patients with cirrhosis (p < .05). In patients with cirrhosis, the reactivity to norepinephrine and angiotensin II was markedly reduced (p < .05 vs. controls). Coadministration of vitamin C completely restored the potency of vasoconstrictors to that in controls but had no effect in healthy subjects. No changes were observed in time-control experiments in cirrhosis patients (n = 3) employing vehicle coinfusion. The response to N-monomethyl-L-arginine was comparable between groups and not affected by vitamin C. CONCLUSIONS: Oxidative stress with consumption of antioxidants seems to play an important role in the development of vasoconstrictor hyporeactivity in patients with cirrhosis. Antioxidant therapy may be a promising clinical approach to restore vasoconstrictor hyporeactivity in these patients.

Changes in thrombopoiesis and platelet reactivity in extremely low birth weight infants undergoing erythropoietin therapy for treatment of anaemia of prematurity.

Erythropoietin (Epo) is frequently administered to premature infants to stimulate erythropoiesis. There is evidence from studies in animals and healthy adults that Epo also interacts with thrombopoiesis and platelet function. This study investigates the effect of Epo therapy on platelet reactivity, peripheral platelet counts and thiazole orange-positive (TO+) platelets in extremely low birth weight (ELBW) infants. In a randomised-controlled trial, ELBW infants with a birth weight < or =800 g and a gestational age < or =32 weeks were either randomised to a group receiving Epo during the first weeks of life or to a control group. Our results show that thrombin receptor-activating peptide (TRAP-6) -induced expression of P-selectin increased significantly during the first two weeks of Epo treatment. With the exception of week five, the number of TO+ platelets was significantly higher during the first eight weeks in Epo-treated infants compared to controls. The increase of TO+ platelets was not paralleled by an increase in total platelet count. We can conclude that Epo therapy has a short-lasting effect on platelet reactivity toTRAP-6 in ELBW infants during the first two weeks of life. Furthermore, Epo therapy is associated with an increase in the number of TO+ platelets compared to controls.

Activation of calcium-dependent calmodulin by calcium(II)3(3,5-diisopropylsalicylate)6(H2O)6 decreases thrombin receptor activating peptide-induced P-selectin expression.

We examined the influence of 3,5-diisopropylsalicylic acid (3,5-DIPS) and calcium(II)3 (3,5-diisopropylsalicylate)6 (H2 O)6 [Ca(II)3 (3,5-DIPS)6 ], a new activator of calcium-dependent calmodulin-triggered nitric oxide synthase, on thrombin-induced platelet P-selectin expression. Citrated whole blood samples were incubated with either ethanol vehicle, 3,5-DIPS, or Ca(II)3 (3,5-DIPS)6. These whole blood samples were also co-incubated with thrombin receptor activating peptide (TRAP) or adenosine diphosphate (ADP), to up-regulate P-selectin (CD62P) on platelets. Both TRAP and ADP up-regulated P-selectin on platelets compared with platelets in whole blood samples that were not incubated with either platelet activator. Co-incubation of whole blood samples with TRAP, ADP together with 3,5-DIPS, or Ca(II)3 (3,5-DIPS)6 revealed that Ca(II)3 (3,5-DIPS)6 caused a decrease in platelet P-selectin expression for TRAP, ADP, and no-activator co-incubated samples of whole blood. Incubation of platelets with 3,5-DIPS also caused a decrease in ADP-induced up-regulation of P-selectin but failed to affect TRAP or no-activator-treated platelets. Incubation of whole blood with Ca(II)3 (3,5-DIPS)6 induced some hemolysis. We found that hemolysis increases basal P-selectin expression on platelets. We therefore conclude that Ca(II)3 (3,5-DIPS)6 decreased not only basal, but also hemolysis-induced P-selectin expression on platelets. In contrast, incubation of haemolysed whole blood with SIN-1 (standard nitric oxide-releasing drug) had no effect on P-selectin expression. In summary, Ca(II)3 (3,5-DIPS)6, a new calmodulin-dependent nitric oxide synthase activator, decreases P-selectin expression of human platelets in response to thrombin receptor activation. Improved calcium-dependent calmodulin activators may become useful drugs for the treatment of disorders associated with platelet activation, and P-selectin may decrease expression due to hemolysis.

Glycoprotein Ib polymorphisms influence platelet plug formation under high shear rates.

Platelet polymorphisms (Kozak, VNTR and HPA-2) within glycoprotein (GP)Ib alpha may be associated with an increased risk of arterial thrombosis. However, the functional role of these polymorphisms has not been clarified. Their influence on platelet plug formation under high shear rates was, therefore, examined in 233 healthy individuals. Collagen-adrenaline-induced closure time was shorter in carriers of the C/D versus C/C VNTR allele and in homozygotes with the (-5)T/T versus (-5)C/T Kozak genotype as determined by novel polymerase chain reaction methods. The HPA-2 genotype had no effects, and the density of GPIb alpha molecules was not influenced by GPIb alpha genotypes.

Effect of factor X inhibition on coagulation activation and cytokine induction in human systemic inflammation.

Anticoagulants have gained increasing attention in the treatment of sepsis. This study used danaparoid to investigate the role of factor Xa in endotoxin-induced coagulation and inflammation and its effectiveness when coagulation activation has already occurred. Thirty healthy volunteers were enrolled in the randomized, placebo-controlled trial. Subjects received 2 ng/kg endotoxin and danaparoid 10 min or 3 h thereafter or placebo. Endotoxin increased prothrombin fragment 1+2 (F(1+2)) levels from 0.5 to 7.0 nmol/L at 5 h in the placebo group. Early danaparoid infusion inhibited endotoxin-induced thrombin formation: maximum F(1+2) levels reached only 1.8 nmol/L (P<.01, vs. baseline or placebo). Delayed danaparoid infusion effectively blocked further thrombin formation. However, danaparoid did not alter endotoxin-induced changes in the fibrinolytic system, cytokine levels, activation of leukocytes, or tissue factor expression on monocytes. Danaparoid therefore selectively attenuates endotoxin-induced coagulopathy, even with delayed administration when coagulation activation is well under way.

Acenocoumarol decreases tissue factor-dependent coagulation during systemic inflammation in humans.

BACKGROUND: Coumarin derivatives are still widely used for prophylaxis of thromboembolic events and therefore represent important comparator substances for new anticoagulants. Measurement of the efficacy of such novel compounds in a human coagulation model with adequate biomarkers could be useful for early-phase clinical drug development. To evaluate the applicability of a well-established model of tissue factor-dependent coagulation for defining anticoagulant potency, we investigated the effects of acenocoumarol in experimental human endotoxemia. METHODS: In a randomized, controlled, 2-by-2 factorial design, healthy volunteers received an infusion of 2 ng/kg endotoxin or placebo after 18 days of pretreatment with acenocoumarol or placebo. Prothrombin fragment 1+2 (F(1+2)), soluble fibrin, and D-dimer were used as markers of thrombin and fibrin formation. RESULTS: As expected, pretreatment with acenocoumarol decreased vitamin K-dependent coagulation factors, but it also decreased spontaneous thrombin formation. Acenocoumarol inhibited endotoxin-induced thrombin generation as measured by F(1+2) levels: endotoxin infusion increased F(1+2) levels 8-fold-from 0.5 to 4.1 nmol/L-in the placebo group, whereas peak F(1+2) levels reached only 1.0 nmol/L in subjects after acenocoumarol pretreatment. This inhibition was also reflected in decreased formation of soluble fibrin and decreased D-dimer levels, showing that depletion of endogenous coagulation factors limits the propagation of nonovert disseminated intravascular coagulation. CONCLUSIONS: Human endotoxemia is a suitable tool for measurement of the efficacy of oral anticoagulants and therefore may become a valuable addition for expeditious pharmacodynamic characterization of lead compounds with anticoagulant potency.

Rapid down modulation of P-selectin glycoprotein ligand-1 (PSGL-1, CD162) by G-CSF in humans.

BACKGROUND: In vitro and animal studies suggest a critical role for P-selectin glycoprotein ligand-1 (PSGL-1) in the regulation of WBC adhesion and neutrophil counts. As WBC activation decreases PSGL-1 expression on WBCs in vitro, the effects of G-CSF on PSGL-1 expression were examined. STUDY DESIGN AND METHODS: Two different G-CSF doses (1 and 5 microg/kg IV) were compared with high-dose dexamethasone (1 mg/kg twice daily) and placebo in a randomized, double-blind, four-way cross-over trial in eight healthy volunteers. Surface expression of WBC adhesion molecules was quantified by flow cytometry. RESULTS: Both G-CSF and dexamethasone led to a delayed down regulation of L-selectin. In contrast, G-CSF rapidly down regulated PSGL-1 expression on neutrophils within 90 minutes, whereas neither dexamethasone nor placebo had an effect. Similarly, incubation of WBCs with clinically relevant G-CSF concentrations (60 microg/L) for 90 minutes down modulated PSGL-1 expression on neutrophils and enhanced CD11b expression, compatible with a direct PSGL-1 down regulation by G-CSF-induced neutrophil activation. Similar to G-CSF, GM-CSF down regulated PSGL-1 in vitro. Both drugs induced shedding of soluble PSGL-1, supporting the concept that proteolytic cleavage is a potential mechanism of PSGL-1 down regulation on neutrophils. CONCLUSION: G-CSF, but not dexamethasone, down regulates PSGL-1 expression on the surface of neutrophils in humans. This could also partly explain the synergistic effects when both drugs are combined for optimal mobilization of neutrophils for clinical granulocyte transfusion programs.

Point of care measurement of lepirudin and heparin anticoagulation during systemic inflammation.

BACKGROUND: The number of indications for recombinant human hirudin lepirudin therapy has increased in recent years, and now includes acute coronary syndromes and heparin-induced thrombocytopenia. Hence, point of care monitoring appears desirable for therapy with lepirudin. As CoaguChek Plus (CCP) provides a rapid bedside test to monitor therapy with other anticoagulants, we aimed to determine its suitability for lepirudin therapy. METHODS: Forty-four healthy volunteers received a 2 ng/kg endotoxin infusion (to induce coagulation) together with clinically relevant doses of lepirudin or heparin in a prospective, placebo-controlled, randomised fashion. Measurements of CCP-partial thromboplastin time (aPTT) were compared to laboratory STA-aPTT. RESULTS: As expected, baseline values of CCP-aPTT were shorter than STA-aPTT. Lepirudin increased CCP-aPTT 3-fold, and STA-aPTT 2-fold 1 h after bolus infusion. During lepirudin infusion, the correlation between CCP-aPTT and STA-aPTT was excellent (r=0.86-0.92). Both methods were equally sensitive to over-anticoagulation with heparin. Acute systemic inflammation had little effects on CCP-aPTT. CONCLUSION: CCP-aPTT is suitable for longitudinal point of care monitoring of lepirudin therapy. As baseline values of CCP-aPTT are shorter than STA-aPTT, it is recommended not to indiscriminately change between methods in the follow-up of individual patients.