What does cerebral platelet activation mean in the setting of carotid stenosis?
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Brain↗
Biomedical subjects
Karen L Kaplan
Publications and source records attributed to Karen L Kaplan.
Venous thromboembolism in patients with diffuse large B-cell lymphoma.
We conducted a retrospective record review to determine the frequency of venous thromboembolism (VTE) in patients with diffuse large B-cell lymphoma (DLBCL). All records from 1990 to 2001 of patients with the diagnosis of DLBCL at a tertiary care hospital were reviewed. Those with transformation from low-grade lymphoma, central nervous system lymphoma, HIV-related lymphoma or with incomplete records were excluded. All episodes of symptomatic VTE confirmed by imaging studies that were either present at diagnosis or occurred during initial treatment were identified. VTE occurred in 27 of 211 patients (12.8%). Stage I disease was associated with a low risk, whereas a high international prognostic index score increased risk. Of patients with VTE, thrombosis was present at diagnosis in 37% and occurred during the first chemotherapy cycle in 22% and during the first three cycles in 82%. The median survival of patients with VTE was 1.04 years [95% confidence interval (CI) = 0.75 - 1.33] compared to 5.2 years (95% CI 1.8 - 8.6) for those without VTE (P = 0.038). We conclude that VTE is a frequent complication of DLBCL that occurs particularly at diagnosis and during initial therapy, and it is associated with a worse prognosis.
Adult↗
Nicardipine versus nitroprusside for deliberate hypotension during idiopathic scoliosis repair.
STUDY OBJECTIVE: To compare coagulation, blood loss, and transfusion requirements between patients receiving nicardipine and nitroprusside for deliberate hypotension during idiopathic scoliosis repair. DESIGN: Prospective, randomized study. SETTING: University hospital. PATIENTS: 51 ASA physical status I patients presenting for spine fusion for idiopathic adolescent scoliosis. INTERVENTIONS: Patients were randomized to two groups to receive nicardipine or nitroprusside to maintain mean arterial pressure (MAP) between 55 and 65 mmHg. MEASUREMENTS: Blood loss, blood transfusions, and coagulation studies (thromboelastogram and platelet aggregation) before starting vasodilator, 30 minutes and 90 minutes after starting vasodilator, and 30 minutes after stopping vasodilator, were all recorded. MAIN RESULTS: There was no difference between the groups in blood loss [nicardipine = 1,129 cc (893 to 1,480), nitroprusside = 960 cc (704 to 1,473)] and only one patient required a nonautologous transfusion. There were no differences in prothrombin time (pT, partial thromboplastin time (pTT), platelet count, or platelet aggregation between groups. There were more episodes of severe hypotension (MAP <45 mmHg) in the nitroprusside group (0% vs. 28%, p = 0.0175). On average, patients in the nicardipine group spent 21 minutes less in the recovery room than did the nitroprusside group (p = 0.043). CONCLUSIONS: Nitroprusside's effect on platelet aggregation produces no increase in blood loss compared with nicardipine. Nicardipine causes less transient severe hypotension than nitroprusside, although both drugs are acceptable choices for obtaining the goals of deliberate hypotension.
Adolescent↗
Patients with inferior vena caval filters should receive chronic thromboprophylaxis.
A 32-year-old man with testicular carcinoma is diagnosed with an acute left leg deep venous thrombosis (DVT) during his fourth cycle of combination chemotherapy. Because of anticipated moderate to severe thrombocytopenia, anticoagulation is initially avoided and an inferior vena cava (IVC) filter is placed to prevent pulmonary embolism (PE). After completion of all chemotherapy he is deemed to be in remission and anticoagulation is begun. The optimal duration of anticoagulation in this patient is pondered.
Adult↗
De novo thrombotic microangiopathy in renal transplant recipients: a comparison of hemolytic uremic syndrome with localized renal thrombotic microangiopathy.
BACKGROUND: Thrombotic microangiopathy (TMA) is a well-recognized and serious complication of renal transplantation, affecting 3% to 14% of patients administered calcineurin-inhibitor-based immunosuppression. METHODS: We reviewed 1,219 biopsy reports of 742 kidney and kidney-pancreas transplants performed during 15 years at our center and found 21 biopsy-confirmed cases of TMA. RESULTS: On presentation, the majority (62%) had systemic TMA with manifest hemolysis and thrombocytopenia, whereas a subset had TMA localized only to the graft (38%). There were no statistically significant differences in sex, type of transplant, age, race, or type of immunosuppression. Patients with systemic TMA were more likely to be treated with plasma exchange (38% versus 13%; P < 0.05), more often required dialysis therapy (54% versus 0%; P = 0.01), and had a greater rate of graft loss (38% versus 0%; P < 0.05). No patient with the localized variant had TMA-related graft loss. Patients with localized TMA often responded to reduction, conversion, or temporary discontinuation of calcineurin-inhibitor-based immunosuppression therapy and did not routinely require plasma exchange for graft salvage. We compare our findings with the literature regarding the prognosis of TMA. CONCLUSION: Classifying patients with post-renal transplantation TMA into those with localized and systemic disease is clinically useful because each group has distinct characteristics and clinical courses.
Acute Kidney Injury↗
Direct thrombin inhibitors.
This review deals with a newly-developed category of antithrombotic drugs - the direct thrombin inhibitors. These agents interact with thrombin and block its catalytic activity on fibrinogen, platelets and other substrates. Heparin and its derivatives (low molecular weight heparins and the active pentasaccharide) inhibit thrombin and/or other coagulation serine proteases indirectly via antithrombin, and the warfarin-type drugs interfere with the synthesis of the precursors of the coagulation serine proteases. The direct thrombin inhibitors approved for clinical use at present (lepirudin, desirudin, bivalirudin, argatroban) and another in the advanced clinical testing stage (melagatran/ximelagatran), are the subject of this review. The chemical structure; kinetics of thrombin inhibition; pharmacokinetics and clinical use of each of these is discussed.
Antithrombins↗
Use of thrombolytic therapy for acute myocardial infarction: effects of gender and age on treatment rates.
BACKGROUND: Although there have been efforts to increase the utilization of thrombolytic therapy, there are still many patients who might benefit from this treatment who do not receive it. Women and the elderly have been particularly undertreated, despite evidence that their survival can be improved with thrombolysis. This study was undertaken to determine the relative rates of treatment of women vs. men and the elderly vs. younger subjects and to examine factors that might explain differences in treatment frequency. METHODS AND RESULTS: This is a retrospective study of patients who presented to the Emergency Departments of four local hospitals in 1993 and 1994 with evidence for acute ST-elevation myocardial infarction. Demographic data, past medical history, information on co-morbid illnesses, and times to hospital arrival, first electrocardiogram, physician notification, and thrombolytic therapy were recorded as was survival to hospital discharge. Data for patients who did or did not receive thrombolytic therapy were compared. Men were treated more frequently in both tertiary and community hospitals. Women were older, but within each age bracket, men were treated more often. The time of arrival was similar for men and women, but men who arrived within 6 hours or 6-12 hours after pain onset were treated at a higher rate than women. For patients without contraindications, treatment was not affected by gender or age. However, treatment rates decreased with increased prevalence of exclusionary factors, and since both women and the elderly tended to have more such factors, elderly women were treated at a markedly lower rate. The single clinical factor that increased thrombolytic usage in women compared to men was a history of prior myocardial infarction. CONCLUSION: Despite convincing evidence that thrombolytic therapy is beneficial in women and the elderly, these groups have been relatively neglected unless attention is called to clinical risk, for example, by history of prior myocardial infarction.
Age Factors↗
Direct thrombin inhibitors.
Direct thrombin inhibitors interact with thrombin and block its catalytic activity on a wide range of substrates. Their action is in contrast to heparin and its derivatives, which inhibit thrombin and other coagulation serine proteases via antithrombin, and to the warfarin-type drugs that interfere with synthesis of the precursors of the coagulation serine proteases. There are three direct thrombin inhibitors approved for clinical use at present (lepirudin, bivalirudin, argatroban) and another in advanced clinical testing (melagatran/ximelagatran). The chemical structure, kinetics of thrombin inhibition, pharmacokinetics, and clinical use of each of these agents are discussed.
Animals↗