Calorie restriction and cancer prevention: a mechanistic perspective.

Calorie restriction (CR) is one of the most potent broadly acting dietary interventions for inducing weight loss and for inhibiting cancer in experimental models. Translation of the mechanistic lessons learned from research on CR to cancer prevention strategies in human beings is important given the high prevalence of excess energy intake, obesity, and metabolic syndrome in many parts of the world and the established links between obesity-associated metabolic perturbations and increased risk or progression of many types of cancer. This review synthesizes findings on the biological mechanisms underlying many of the anticancer effects of CR, with emphasis on the impact of CR on growth factor signaling pathways, inflammation, cellular and systemic energy homeostasis pathways, vascular perturbations, and the tumor microenvironment. These CR-responsive pathways and processes represent targets for translating CR research into effective cancer prevention strategies in human beings.

Growth signals, inflammation, and vascular perturbations: mechanistic links between obesity, metabolic syndrome, and cancer.

Nearly 35% of adults and 20% of children in the United States are obese, defined as a body mass index ≥ 30 kg/m(2). Obesity, which is accompanied by metabolic dysregulation often manifesting in the metabolic syndrome, is an established risk factor for many cancers. Within the growth-promoting, proinflammatory environment of the obese state, cross talk between macrophages, adipocytes, and epithelial cells occurs via obesity-associated hormones, cytokines, and other mediators that may enhance cancer risk and progression. This review synthesizes the evidence on key biological mechanisms underlying the obesity-cancer link, with particular emphasis on obesity-associated enhancements in growth factor signaling, inflammation, and vascular integrity processes. These interrelated pathways represent possible mechanistic targets for disrupting the obesity-cancer link.

Etiology and assessment of hypercoagulability with lessons from heparin-induced thrombocytopenia.

Hypercoagulability, or thrombophilia, is a condition associated with an abnormally increased tendency toward blood clotting. Affected individuals are prone to developing venous or arterial thrombosis and often require thromboprophylaxis. Hypercoagulability can be generally classified as either an inherited or acquired condition. Patients with an inherited thrombophilia have genetic variances that alter the quality or quantity of proteins involved with hemostasis. Hypercoagulability may also be acquired and develop as an exaggeration of normal physiologic responses to major tissue injury, or an abnormal response to various prothrombotic clinical factors. Careful assessment for hypercoagulability is important because effective management strategies, often involving anticoagulation, may be available. Heparin-induced thrombocytopenia is an example of an acquired hypercoagulable state that has been well studied and, when recognized, responds to appropriate therapy. In this article, we review the etiology, risks, and assessment of thrombophilia, with emphasis on the clinical lessons learned from heparin-induced thrombocytopenia.

Platelet factor 4/heparin antibodies in blood bank donors.

Platelet factor 4 (PF4)/heparin antibody, typically associated with heparin therapy, is reported in some heparin-naive people. Seroprevalence in the general population, however, remains unclear. We prospectively evaluated PF4/heparin antibody in approximately 4,000 blood bank donors using a commercial enzyme-linked immunosorbent assay for initial and then repeated (confirmatory) testing. Antibody was detected initially in 249 (6.6%; 95% confidence interval [CI], 5.8%-7.4%) of 3,795 donors and repeatedly in 163 (4.3%; 95% CI, 3.7%-5.0%) of 3,789 evaluable donors. "Unconfirmed" positives were mostly (93%) low positives (optical density [OD] = 0.40-0.59). Of 163 repeatedly positive samples, 116 (71.2%) were low positives, and 124 (76.1%) exhibited heparin-dependent binding. Predominant isotypes of intermediate to high seropositive samples (OD >0.6) were IgG (20/39 [51%]), IgM (9/39 [23%]), and indeterminate (10/39 [26%]). The marked background seroprevalence of PF4/heparin antibody (4.3%-6.6%) with the preponderance of low (and frequently nonreproducible) positives in blood donors suggests the need for further assay calibration, categorization of antibody level, and studies evaluating clinical relevance of "naturally occurring" PF4/heparin antibodies.

Emergency department awareness of heparin-induced thrombocytopenia: how frequently is risk assessment documented in patients with thrombosis?

Evidence-based guidelines recommend that heparin-induced thrombocytopenia (HIT) should be suspected whenever a patient develops thrombosis or thrombocytopenia 5 to 14 days after heparin initiation. The authors determined how frequently emergency department (ED) physicians document HIT risk assessment in patients presenting with thrombosis. Relevant data were extracted from the ED charts of 134 patients with venous or arterial thrombosis. Documentation (ie, notation of positive or negative findings) existed for recent heparin exposure in 7 (5.2%) of 134 charts, recent hospitalization in 33 (24.6%), history of thrombocytopenia in 0 (0%), and history of thrombosis in 62 (45.5%). Of 35 patients administered heparin in the ED, the preheparin platelet count was available for 19 (54.3%) and old records for 5 (14.3%). Thus, HIT risk assessment frequently remains undocumented for ED patients with thrombosis, including those administered heparin. Approaches to increase HIT awareness and facilitate HIT risk assessment and documentation in the ED may be needed.

Heparin-platelet factor 4 antibodies in intensive care patients: an observational seroprevalence study.

Heparin-platelet factor 4 (PF4) antibodies mediate heparin-induced thrombocytopenia (HIT) and, irrespective of thrombocytopenia, are associated with poorer outcomes in some patients. The prevalence of heparin-PF4 antibodies, including platelet-activating ones, in patients in the medical, neurotrauma, or shock-trauma intensive care unit (ICU) remains unclear. In this single-center, observational study, heparin-PF4 antibodies (IgG/A/M) were measured by ELISA in 185 adults (median APACHE II score, 16) admitted to the medical (n = 27), neurotrauma (n = 96), or shock-trauma (n = 62) ICU and after 7 +/- 2 days. Seropositive patients and heparin-treated patients with unexplained, new-onset thrombocytopenia were also tested for platelet-activating antibodies using a serotonin release assay (SRA). Of 185 patients, seropositivity occurred in 20 patients (10.8%; 95% CI 6.7-16.2%) at admission and 54 (29.2%, 95% CI 22.8-36.3%) after 7 days (P < 0.001). Platelet-activating antibodies occurred in 4 seropositive patients at admission and 9 seropositive patients after 7 days (including in 1 patient at each assessment), each without thrombocytopenia or new thrombosis. Of 12 seropositive patients with platelet-activating antibodies, 6 had an ELISA optical density (OD) >1.0. ELISA-positive, SRA-negative, suspected HIT occurred in 1 patient. Heparin-PF4 antibodies are present in 10.8% of medical, neurotrauma, or shock-trauma ICU patients at admission and increase significantly to 29.2% within 7 days. Approximately 17-20% of seropositive ICU patients, often those with an ELISA OD >1.0, have platelet-activating heparin-PF4 antibodies.

Impact of renal function on argatroban therapy during percutaneous coronary intervention.

Argatroban, a hepatically metabolized direct thrombin inhibitor, is approved for anticoagulation in patients with or at risk of heparin-induced thrombocytopenia (HIT) undergoing percutaneous coronary intervention (PCI). We investigated the effect of renal function on argatroban therapy during PCI. From previous argatroban studies in PCI, we evaluated relationships between estimated creatinine clearance (CrCl) and activated clotting times (ACTs), dosage, and outcomes in 219 patients with or at risk of HIT (HIT group, n = 67) or administered glycoprotein IIb/IIIa inhibition (non-HIT group, n = 152). Patients received an argatroban bolus (350 mcg/kg, HIT group; 250 or 300 mcg/kg, non-HIT group) then 25-30 mcg/kg/min (adjusted to achieve ACTs 300-450 s, HIT group) or 15 mcg/kg/min (target ACTs 275-325 s, non-HIT group), with additional 150-mcg/kg boluses if needed. Of 219 patients, 55 (25%) had CrCl

Reducing harm associated with anticoagulation: practical considerations of argatroban therapy in heparin-induced thrombocytopenia.

Argatroban is a hepatically metabolized, direct thrombin inhibitor used for prophylaxis or treatment of thrombosis in heparin-induced thrombocytopenia (HIT) and for patients with or at risk of HIT undergoing percutaneous coronary intervention (PCI). The objective of this review is to summarize practical considerations of argatroban therapy in HIT. The US FDA-recommended argatroban dose in HIT is 2 microg/kg/min (reduced in patients with hepatic impairment and in paediatric patients), adjusted to achieve activated partial thromboplastin times (aPTTs) 1.5-3 times baseline (not >100 seconds). Contemporary experiences indicate that reduced doses are also needed in patients with conditions associated with hepatic hypoperfusion, e.g. heart failure, yet are unnecessary for renal dysfunction, adult age, sex, race/ethnicity or obesity. Argatroban 0.5-1.2 microg/kg/min typically supports therapeutic aPTTs. The FDA-recommended dose during PCI is 25 microg/kg/min (350 microg/kg initial bolus), adjusted to achieve activated clotting times (ACTs) of 300-450 sec. For PCI, argatroban has not been investigated in hepatically impaired patients; dose adjustment is unnecessary for adult age, sex, race/ethnicity or obesity, and lesser doses may be adequate with concurrent glycoprotein IIb/IIIa inhibition. Argatroban prolongs the International Normalized Ratio, and published approaches for monitoring the argatroban-to-warfarin transition should be followed. Major bleeding with argatroban is 0-10% in the non-interventional setting and 0-5.8% periprocedurally. Argatroban has no specific antidote, and if excessive anticoagulation occurs, argatroban infusion should be stopped or reduced. Improved familiarity of healthcare professionals with argatroban therapy in HIT, including in special populations and during PCI, may facilitate reduction of harm associated with HIT (e.g. fewer thromboses) or its treatment (e.g. fewer argatroban medication errors).

Dosing patterns and outcomes in African American, Asian, and Hispanic patients with heparin-induced thrombocytopenia treated with argatroban.

We retrospectively evaluated dosing patterns and 37-day outcomes in argatroban-treated African American (n = 52), Asian (n = 13), and Hispanic (n = 14) patients with heparin-induced thrombocytopenia (HIT). The Asians required a lesser median dose (1.0 microg/kg/min) than the other groups (1.9 microg/kg/min, each) to achieve comparable activated partial thromboplastin times (medians: 61-69 s). Durations of therapy were similar (medians: 4.0-5.5 days). New thrombosis occurred in 11 (21%) African Americans, 1 (8%) Asian, and 1 (7%) Hispanic; of these 13 patients, 9 (69%) had baseline HIT-related thrombosis. Amputation occurred in 6 (12%) African Americans and 3 (21%) Hispanics; of these nine patients, 6 (67%) had diabetes. One (2%) African American and 1 (7%) Hispanic died from thrombosis. The composite of death due to thrombosis, amputation due to ischemic complications of HIT, or new thrombosis occurred in 14 (27%) African Americans, 1 (8%) Asian, and 4 (29%) Hispanics. Two (4%) African Americans and none others (0%) had major bleeding. These findings suggest that despite argatroban anticoagulation, African Americans and Hispanics may have worse outcomes in HIT than Asians. In minority patients with adverse HIT outcomes, baseline HIT-related thrombosis or diabetes is often present.

Risk factors for major bleeding in patients with heparin-induced thrombocytopenia treated with argatroban: a retrospective study.

We retrospectively characterized major bleeding events and their risk factors among 269 patients with clinically diagnosed heparin-induced thrombocytopenia (HIT) treated using argatroban (2 microg x kg(-1) x min(-1) initially, adjusted to achieve activated partial thromboplastin times (aPTTs) 1.5-3 times the baseline) in a prospective multicenter study. Patients received a median (range) dose of 1.9 (0.2-9.7) microg x kg(-1) x min(-1) for 5.6 (0.1-61) days. Average aPTTs during therapy were 61.6 (37-183) seconds. Major bleeding, most commonly gastrointestinal, occurred in 19 patients (7.1%) during therapy. Another patient suffered from intracranial hemorrhage 4 days after argatroban cessation. Bleeding was fatal in 2 patients (0.7%); each received multiple anticoagulants and thrombolytic therapy. Major bleeding was more likely to occur in patients with HIT-related thrombosis (odds ratio = 2.9, P = 0.039), pulmonary impairment (odds ratio = 20.3, P < 0.001), or an aPTT >100 seconds (odds ratio = 3.7, P = 0.010). Major bleeding rates associated with average aPTTs of <45, 45-67.5, 67.6-90, and >90 seconds, respectively, were 5.0% (1 of 20 patients), 5.6% (9 of 162 patients), 8.7% (6 of 69 patients), and 22% (4 of 18 patients). No significant effect of patient demographics, other baseline illnesses including hepatic or renal impairment, argatroban dose, or treatment duration was detected on major bleeding. Risk factors for major bleeding in argatroban-treated patients with HIT include baseline HIT-related thrombosis and pulmonary impairment. For minimizing bleeding risk during argatroban therapy for HIT, the aPTT should be routinely monitored and maintained at <90 seconds.

Predictors of clinical outcome in patients with heparin-induced thrombocytopenia treated with direct thrombin inhibition.

We aimed to identify predictors of poor outcome in patients with heparin-induced thrombocytopenia, a serious immune-mediated reaction to heparin. All patients were treated with direct thrombin inhibition therapy, as part of two prospective studies. We performed a risk factor analysis of adverse outcomes (defined as death, amputation, new thrombosis, or their composite within a 37-day study period) in 809 patients from two reported prospective studies of the direct thrombin inhibitor argatroban in clinically diagnosed heparin-induced thrombocytopenia. We initially identified from among 14 baseline variables the significant predictors of poor outcome in the first study (304 patients), and then tested our resultant hypothesis in the second, independent study (505 patients), using multivariate analysis. Seven significant predictors were identified in the first study; three were confirmed in the second study. The strongest relationship occurred between the baseline platelet count and the composite of death, amputation, or new thrombosis (P = 0.0001), with the most severely thrombocytopenic patients being at greatest risk. The other significant associations were between renal impairment and death (odds ratio = 2.13, 95% confidence interval = 1.23-3.66, P = 0.007), and between cardiovascular surgery (particularly peripheral vascular surgery) and amputation (odds ratio = 3.39, 95% confidence interval = 1.65-6.95, P = 0.0009). In conclusion, in patients with clinically diagnosed heparin-induced thrombocytopenia, the severity of the baseline thrombocytopenia is the best predictor of death, amputation or thrombotic progression. The identification of higher risk subgroups for poor outcomes, such as patients with more severe thrombocytopenia or a history of renal impairment or peripheral vascular surgery, could allow more targeted therapy.

Argatroban anticoagulation in intensive care patients: effects of heart failure and multiple organ system failure.

We retrospectively evaluated argatroban dosing patterns, clinical outcomes, and the effects of heart failure and multiple organ system failure on dosing requirements in 65 adult, intensive care patients administered argatroban anticoagulation for clinically suspected heparin-induced thrombocytopenia (n=56) or history of heparin-induced thrombocytopenia (n=9). Argatroban was initiated then titrated to achieve target activated partial thromboplastin times 1.5 to 3 times normal control (ie, 42-84 seconds). Overall, argatroban was initiated at 1.14+/-0.62 microg/kg/min (mean+/-SD) and administered for 11.4+/-9.5 days, with comparable dosing patterns between patients with suspected, versus previous, heparin-induced thrombocytopenia. Sixty-four (98.5%) patients achieved target activated partial thromboplastin times, typically following no or one dose adjustment. Therapeutic doses were lower in patients with, versus without, heart failure (0.58+/-0.28 vs 0.97+/-0.6 microg/kg/min, P= .042) and decreased as the number of failed organ systems increased from 1 to 2 to =3 (1.10+/-0.67 vs 0.87+/-0.47 vs 0.58+/-0.47 microg/kg/min, P= .008). From argatroban initiation until patient discharge or death, 11 (16.9%) patients (3 off argatroban) developed thromboembolic complications; 14 (21.5%) died (11 off argatroban, 7 from multiple organ system failure); and 1 (1.5%) required amputation. Nine patients (13.8%) experienced bleeding, none fatal. This experience suggests that argatroban administered at approximately 1 micro/kg/min provides adequate levels of anticoagulation in many intensive care unit patients with suspected or previous heparin-induced thrombocytopenia. Reduced doses are needed when heart failure or multiple organ system failure is present.

Argatroban anticoagulation in renal dysfunction: a literature analysis.

BACKGROUND/AIMS: Argatroban, a hepatically metabolized direct thrombin inhibitor, is approved for use in heparin-induced thrombocytopenia (HIT; several countries) and in antithrombin-deficient patients undergoing hemodialysis (Japan). This literature analysis aimed to determine the effects of renal function on argatroban pharmacokinetics, pharmacodynamics, and its therapeutic dose in HIT and to evaluate argatroban dosing and safety during renal replacement therapy (RRT) and in adults with renal dysfunction undergoing surgical or invasive procedures. METHODS: A literature search identified 34 publications (12 prospective studies, 4 retrospective studies, 18 anecdotal reports) that together described 644 argatroban-treated patients (446 with HIT, 82 with antithrombin deficiency) with varying degrees of renal function. Pertinent data were extracted and summarized. RESULTS: In pharmacokinetic studies (40 patients, overall), renal dysfunction exerted little or no clinically significant effects on argatroban pharmacokinetic parameters. For argatroban therapy in HIT, evidence existed that an initial 2 microg/kg/min dose was sometimes excessive; patients with hepatic dysfunction, irrespective of renal function, required reduced initial doses; lesser doses were required in combined hepatic and renal dysfunction than hepatic dysfunction, and for each 30 ml/min decrease in patient creatinine clearance, the therapeutic dose decreased approximately 0.1-0.6 microg/kg/min. Argatroban was well tolerated and enabled RRT with little or no thrombotic or hemorrhagic complications. Experiences with argatroban in renally impaired patients undergoing procedures besides RRT were limited. CONCLUSION: Current literature suggests that argatroban is well tolerated and provides adequate anticoagulation in patients with renal dysfunction or failure, including individuals with HIT or antithrombin deficiency where anticoagulant options are limited.

Platelet factor 4/heparin antibody (IgG/M/A) in healthy subjects: a literature analysis of commercial immunoassay results.

PURPOSE: We determined the seroprevalence of platelet factor 4 (PF4)/heparin antibodies in healthy subjects. METHODS: A literature search identified studies in which healthy subjects were evaluated using commercial immunoassays for PF4/heparin antibody (IgG/M/A). Proportions of test-positive subjects were calculated, by assay. RESULTS: Across 11 eligible studies, 860 healthy subjects were tested using the Stago enzyme-linked immunosorbent assay (ELISA) (nine studies), GTI ELISA (three studies), and/or DiaMed particle gel immunoassay (PGIA) (three studies). Seropositivity occurred in 17 of 790 (2.2%, 95% CI, 1.1-3.2%) subjects by Stago ELISA, one of 100 (1.0%, 95% CI, 0-3.0%) subjects by GTI ELISA, and three of 70 (4.3%, 95% CI, 0-9.0%) subjects by PGIA (P > 0.20). Of seven seropositive subjects tested further, none had platelet-activating antibodies. CONCLUSION: Commercial immunoassays detect PF4/heparin antibody in 1.0-4.3% of healthy subjects. Because this "background" prevalence overlaps seropositivity rates in heparin-treated patients in various clinical settings, normality cut-offs may require refinement.

Reduced argatroban doses after coronary artery bypass graft surgery.

BACKGROUND: The Food and Drug Administration-approved argatroban dose for heparin-induced thrombocytopenia (HIT) is 2 microg/kg/min (0.5 microg/kg/min in hepatic impairment), adjusted to achieve activated partial thromboplastin time (aPTT) 1.5-3 times baseline. Recent data suggest that reduced doses are required after cardiovascular surgery. OBJECTIVE: To characterize dosing requirements, aPTTs, factors affecting dosage, and clinical outcomes in patients administered argatroban after coronary artery bypass graft (CABG) surgery. METHODS: Charts of 39 patients who underwent CABG surgery and were administered argatroban postoperatively for laboratory-confirmed HIT (n = 25), antibody-negative suspected HIT (n = 10), or previous HIT requiring anticoagulation (n = 4) were retrospectively reviewed. Patient characteristics, argatroban dosing information, aPTTs (target range 45-90 sec), and outcomes were summarized. Regression analyses explored potential effectors of dosage. RESULTS: Patient features, argatroban dosing patterns, and aPTTs were similar among groups. Many patients had laboratory evidence of some hepatic and/or renal dysfunction (median [range] bilirubin 1.0 [0.3-8.0] mg/dL, creatinine clearance 47 [18-287] mL/min). Overall, median argatroban doses were 0.5 microg/kg/min initially and 0.6 microg/kg/min during therapy (median duration 5.3 days). After argatroban initiation, aPTTs were greater than 90 seconds at first assessment in 4 patients (3 with abnormal hepatic function test results) initially administered 0.5, 1, 2, and 2 microg/kg/min, respectively. Within approximately 16 hours of therapy, 33 (85%) patients achieved consecutive therapeutic aPTTs. No association was detected between mean dose during therapy and preoperative ejection fraction, routine hepatic or renal function test results (other than blood urea nitrogen [BUN]), or surgery type. A clinically insignificant association existed between dose and BUN: there was an approximately 0.15 microg/kg/min dose decrease for each 10 mg/dL BUN increase. One patient developed thrombosis, 1 underwent finger amputation, 7 died (5 after argatroban cessation), and 4 had significant bleeding. CONCLUSIONS: These findings suggest that reduced initial argatroban doses (eg, 0.5 microg/kg/min), adjusted to achieve therapeutic aPTTs, provide rapid, adequate anticoagulation in postoperative CABG patients with presumed or previous HIT. Prospective study of reduced initial dosing in this setting is warranted.

Argatroban therapy in heparin-induced thrombocytopenia.

Argatroban is a direct thrombin inhibitor approved for anticoagulation in heparin-induced thrombocytopenia (HIT; in several countries) and in patients with or at risk of HIT undergoing percutaneous coronary intervention (PCI; in the USA). HIT is a relatively common extreme prothrombotic condition. When HIT is reasonably suspected, an alternative anticoagulant should be promptly initiated. In historical controlled studies, argatroban reduced new thrombosis, mortality from thrombosis and the composite of death, amputation or thrombosis, without increasing bleeding. With intravenous infusion, advantages include short half-life, easy monitoring and elimination primarily by hepatobiliary (rather than renal) means. In patients undergoing PCI, argatroban with or without glycoprotein IIb/IIIa inhibition leads to high rates of procedural success with low bleeding risk. Herein we review argatroban therapy for HIT and for PCI.

Effect of body mass index on Argatroban therapy during percutaneous coronary intervention.

BACKGROUND: Obesity is common in patients undergoing percutaneous coronary intervention (PCI). Argatroban, a direct thrombin inhibitor, is used during PCI in patients with or at risk of heparin-induced thrombocytopenia (HIT) and also has been evaluated in conjunction with glycoprotein IIb/IIIa inhibition in nonHIT patients. We investigated the effect of body mass index (BMI), and specifically obesity (BMI>30 kg/m2), on argatroban therapy during PCI. METHODS: From previously reported studies of argatroban therapy during PCI in patients with or at risk of HIT (ie, HIT group) or in conjunction with glycoprotein IIb/IIIa inhibition (ie, nonHIT group), we identified patients with sufficient data to determine BMI. After an initial bolus of 350 microg/kg (HIT group) or 300 or 250 microg/kg (nonHIT group), patients received continuous argatroban 25-30 microg/kg/min (adjusted to achieve ACTs of 300-450 s, HIT group) or 15 microg/kg/min (target ACTs of 275-325 s, nonHIT group) during PCI, with additional 150 microg/kg boluses allowed if needed. Regression analyses evaluated relationships between patient BMI and ACT response to initial bolus administration, mean infusion dose (HIT group only), and rate of ACT decline after PCI. Frequencies of additional bolus usage and clinical outcomes were compared between obese and nonobese patients. RESULTS: Our analysis population included 225 patients (85 obese) in total: 73 in the HIT group and 152 in the nonHIT group (300 microg/kg bolus, n=101; 250 microg/kg bolus, n=51), with BMIs of 16.3-50.9 kg/m2. No association was detected between BMI and the first ACT after bolus administration (median ACTs of 361, 298, and 289 s, respectively, following 350, 300, and 250 microg/kg bolus), mean infusion dose (24.2+/-4.9 microg/kg/min overall in HIT group), or time to ACTsor=0.35). Clinical outcomes did not differ (P>or=0.09) between obese and nonobese individuals: 4 (3 obese) patients in the HIT group and 4 (2 obese) in the nonHIT group had ischemic complications; 1 nonobese patient in the HIT group and 2 (1 obese) in the nonHIT group experienced major bleeding. CONCLUSIONS: These findings support the use of actual body weight-adjusted (and ACT-targeted) argatroban therapy during PCI and suggest that dose adjustment for obesity (BMI up to 50.9 kg/m2) is unnecessary.

Argatroban therapy in patients with coronary artery disease and heparin-induced thrombocytopenia.

The efficacy of the direct thrombin inhibitor argatroban was investigated in patients who developed heparin-induced thrombocytopenia following heparin therapy for coronary artery disease. The outcome of 121 patients treated with argatroban was compared with that of 26 patients in a historical control (i.e. patients who did not receive direct thrombin inhibition therapy). Argatroban, compared with controls, significantly reduced the 37-day composite of death, amputation or new thrombosis (30 versus 50%, p = 0.043), primarily driven by a significant decrease in new thrombosis (10 versus 31%, p = 0.01), and led to less bleeding (4 versus 15%, p = 0.046). Therefore, in patients with coronary artery disease who develop heparin-induced thrombocytopenia, argatroban provides safe, effective anticoagulation.

Argatroban therapy for heparin-induced thrombocytopenia in acutely ill patients.

Heparin-induced thrombocytopenia (HIT) is a prothrombotic, immune-mediated adverse reaction to heparin therapy. To evaluate clinical outcomes and effects of argatroban therapy in acutely ill HIT patients. Retrospective analysis. Hospital in-patient. Acutely ill patients with clinically diagnosed HIT from previous multicenter, historically controlled studies of argatroban therapy in HIT. Argatroban, adjusted to maintain activated partial thromboplastin times 1.5 to 3 times baseline, or historical control therapy (ie, no direct thrombin inhibition). We identified 488 patients who received argatroban (N = 390; mean dose of 1.9 microg/kg/min for a mean 6 days) or historical control therapy (N = 98) for HIT. The primary all-cause composite endpoint of death, amputation, or new thrombosis within 37 days occurred in 133 (34.1%) argatroban-treated patients and 38 (38.8%) controls (P = .41). Argatroban, versus control, significantly reduced the primary thrombosis-related composite endpoint of death because of thrombosis, amputation secondary to ischemic complications of HIT, or new thrombosis (17.7% vs 30.6%, P = .007). Significant reductions also occurred in new thrombosis and death because of thrombosis. Major bleeding was similar between groups (7.7% vs 8.2%; P = .84). Adverse outcomes were more likely to occur in patients who were initially diagnosed with HIT and thrombosis, had undergone cardiac surgery, were not white, or had more severe thrombocytopenia. In acutely ill HIT patients, argatroban, versus historical control, provides effective antithrombotic therapy without increasing major bleeding. Patients with more severe thrombocytopenia or HIT-related thrombosis on HIT diagnosis have a poorer prognosis, emphasizing the importance of prompt recognition/ treatment of HIT in acutely ill patients.

Argatroban therapy in women with heparin-induced thrombocytopenia.

OBJECTIVES: Women have increased risk of developing heparin-induced thrombocytopenia (HIT), a serious, immune-mediated prothrombotic condition, and have a worse prognosis when affected. We compared gender differences for treatment and outcomes in HIT patients administered argatroban therapy. METHODS: From a multicenter retrospective registry of argatroban-treated patients, we identified females (n = 42) and males (n = 50) with clinically diagnosed HIT who were administered argatroban