Venous thromboembolism in COVID-19: A meta-summary of cases

OBJECTIVES

To summarize cases of venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT) among coronavirus disease (COVID-19) patients and discuss their symptoms, diagnostic method, clinical features, and prognosis.

METHODS

All major databases were searched for relevant studies published between December 1, 2019 and May 5, 2021.

RESULTS

A total of 233 articles were identified, 22 describing 48 patients were included. A total of 79.1% had PE and 20.9% had DVT. Most patients were men, with a mean age of 56 years. Comorbidities were present in 70.8%, and 85.4% had at least one risk factor of VTE. 56.3% had received anticoagulation therapy. Most patients were treated in the general ward. Complications occurred in 27.1% of the patients, and recovery was achieved in 80.4%.

CONCLUSION

Venous thromboembolism must be suspected even in patients who had received prior anticoagulant regimens or in stable cases, especially in males, the elderly, and patients with comorbidities and high D-dimer levels.

Methodological Issues and Controversies in COVID-19 Coagulopathy: A Tale of Two Storms

Venous thromboembolism, occlusion of dialysis catheters, circuit thrombosis in ECMO devices, all in the face of prophylactic and sometimes even therapeutic anti-coagulation, are frequent features of COVID-19 coagulopathy. The trials available to guide clinicians are methodologically limited. There are several unresolved controversies including 1) Should all hospitalized patients with COVID-19 receive prophylactic anti-coagulation? 2) Which patients should have their dosage escalated to intermediate dose? 3) Which patients should be considered for full-dose anti-coagulation even without a measurable thromboembolic event and how should that anti-coagulation be monitored? 4) Should patients receive post-discharge anti-coagulation? 5) What thrombotic issues are related to the various medications being used to treat this coagulopathy? 6) Is anti-phospholipid anti-body part of this syndrome? 7) How do the different treatments for this disease impact the coagulation issues? The aims of this article are to explore these questions and interpret the available data based on the current evidence.

General practitioner use of D-dimer in suspected venous thromboembolism: historical cohort study in one geographical region in the Netherlands

OBJECTIVES

To investigate how many general practitioner (GP)-referred venous thromboembolic events (VTEs) are diagnosed during 1 year in one geographical region and to investigate the (urgent) referral pathway of VTE diagnoses, including the role of laboratory D-dimer testing.

DESIGN

Historical cohort study.

SETTING

GP patients of 47 general practices in a demarcated geographical region of 161 503 inhabitants in the Netherlands.

PARTICIPANTS

We analysed all 895 primary care patients in whom either the GP determined a D-dimer value or who had a diagnostic work-up for suspected VTE in a non-academic hospital during 2015.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcomes of this study were the total number of VTEs per year and the diagnostic pathways-including the role of GP determined D-dimer testing-of patients urgently referred to secondary care for suspected VTE. Additionally, we explored the use of an age-adjusted D-dimer cut-off.

RESULTS

The annual VTE incidence was 0.9 per 1000 inhabitants. GPs annually ordered 5.1 D-dimer tests per 1000 inhabitants. Of 470 urgently GP-referred patients, 31.3% had a VTE. Of those urgently referred based on clinical assessment only (without D-dimer testing), 73.8% (96/130) had a VTE; based on clinical assessment and laboratory D-dimer testing yielded 15.0% (51/340) VTE. Applying age-adjusted D-dimer cut-offs to all patients aged 50 years or older resulted in a reduction of positive D-dimer results from 97.9% to 79.4%, without missing any VTE.

CONCLUSIONS

Although D-dimer testing contributes to the diagnostic work-up of VTE, GPs have a high detection rate for VTE in patients who they urgently refer to secondary care based on clinical assessment only.

Fibrin/fibrinogen degradation products (FDP) at hospital admission predict neurological outcomes in out-of-hospital cardiac arrest patients

OBJECTIVE

This study aimed to test the hypothesis that coagulation, fibrinolytic markers and disseminated intravascular coagulation (DIC) score (International Society on Thrombosis and Haemostasis) at hospital admission of out-of-hospital cardiac arrest (OHCA) patients can predict neurological outcomes 1 month after cardiac arrest.

METHODS

In this retrospective, observational analysis, data were collected from the Sapporo Utstein Registry and medical records at Hokkaido University Hospital. We included patients who experienced OHCA with successful return of spontaneous circulation (ROSC) between 2006 and 2012 and were transferred to Hokkaido University Hospital. From medical records, we collected information about the following coagulation and fibrinolytic factors at hospital admission: platelet count; prothrombin time; activated partial thromboplastin time; plasma levels of fibrinogen, D-dimer, fibrin/fibrinogen degradation products (FDP), and antithrombin; and calculated DIC score. Favorable neurological outcomes were defined as a cerebral performance category 1-2.

RESULTS

We analyzed data for 315 patients. Except for fibrinogen level, all coagulation variables, fibrinolytic variables, and DIC score were associated with favorable neurological outcomes. In the receiver operating characteristic curve analysis, FDP level had the largest area under the curve (AUC; 0.795). In addition, the AUC of FDP level was larger than that of lactate level.

CONCLUSIONS

All of the coagulation and fibrinolytic markers, except for fibrinogen level, and DIC score at hospital admission, were associated with favorable neurological outcomes. Of all of the variables, FDP level was most closely associated with favorable neurological outcomes in OHCA patients who successfully achieved ROSC.

Deep Vein Thrombosis in the Lower Extremities in Comatose Elderly Patients with Acute Neurological Diseases

PURPOSE

Comatose elderly patients with acute neurological illness have a great risk of deep vein thrombosis (DVT). In this study, the incidence of DVT and the effectiveness of early initiation of treatment were evaluated in those patients.

MATERIALS AND METHODS

Total 323 patients were admitted to our ward due to neurological diseases in one year, and 43 patients, whose Glasgow Coma Scale was ≤ 11 and who was older than ≥ 60 years, were included in this study. D-dimer was measured on admission and day 7, and lower-extremity ultrasonography was performed on day 7. When DVT was positive, heparin treatment was initiated, and further evaluation of pulmonary embolism (PE) was conducted. Vena cava filter protection was inserted in PE-positive patients. Incidence of DVT and PE, alteration of D-dimer value, and effect of heparin treatment were analyzed.

RESULTS

DVT was positive in 19 (44.2%) patients, and PE was in 4 (9.3%). D-dimer was significantly higher in DVT-positive group on day 7 (p<0.01). No DVT were identified in patients with ischemic disease, while 66.7% of intracerebral hemorrhage and 53.3% of brain contusion patients were DVT positive. Surgery was a definite risk factor for DVT, with an odds ratio of 5.25. DVT and PE disappeared by treatment in all cases, and no patients were succumbed to the thrombosis.

CONCLUSION

Patients with hemorrhagic diseases or who undergo operation possess high risk of DVT, and initiation of heparin treatment in 7 days after admission is an effective prophylaxis for DVT in comatose elderly patients without causing bleeding.

Severe Ebola virus disease with vascular leakage and multiorgan failure: treatment of a patient in intensive care

BACKGROUND

In the current epidemic of Ebola virus disease in western Africa, many aid workers have become infected. Some of these aid workers have been transferred to specialised hospitals in Europe and the USA for intensified treatment, providing the potential for unique insight into the clinical course of Ebola virus disease under optimised supportive measures in isolation units.

METHODS

A 38-year-old male doctor who had contracted an Ebola virus infection in Sierra Leone was airlifted to University Hospital Frankfurt, Germany, on day 5 after disease onset. Within 72 h of admission to the hospital's high-level isolation unit, the patient developed signs of severe multiorgan failure, including lungs, kidneys, and gastrointestinal tract. In addition to clinical parameters, the diagnostic work-up included radiography, ultrasound, pulse contour cardiac output technology, and microbiological and clinical chemistry analyses. Respiratory failure with pulmonary oedema and biophysical evidence of vascular leak syndrome needed mechanical ventilation. The patient received a 3 day treatment course with FX06 (MChE-F4Pharma, Vienna, Austria), a fibrin-derived peptide under clinical development for vascular leak syndrome. After FX06 administration and concurrent detection of Ebola-virus-specific antibodies and a fall in viral load, vascular leak syndrome and respiratory parameters substantially improved. We gave broad-spectrum empiric antimicrobial therapy and the patient needed intermittent renal replacement therapy. The patient fully recovered.

FINDINGS

This case report shows the feasibility of delivery of successful intensive care therapy to patients with Ebola virus disease under biosafety level 4 conditions.

INTERPRETATION

The effective treatment of vascular leakage and multiorgan failure by combination of ventilatory support, antibiotic treatment, and renal replacement therapy can sustain a patient with severe Ebola virus disease until virological remission. FX06 could potentially be a valuable agent in contribution to supportive therapy.

FUNDING

University Hospital of Frankfurt.

D-dimer for the diagnosis of upper extremity deep and superficial venous thrombosis

BACKGROUND

D-dimer role is well established in the diagnostic work-up for lower limb deep vein thrombosis (DVT), however it has not been formally tested for clinically suspected upper extremity DVT and/or superficial vein thrombosis (SVT).

AIM

To ascertain D-dimer diagnostic accuracy for upper extremity DVT and/or SVT.

STUDY DESIGN

We performed a single centre management study in outpatients referred by emergency or primary care physicians for clinically suspected upper extremity DVT. All patients underwent D-dimer testing (cut-off value: ≤500 ng/mL), and a B-mode and color Doppler ultrasonography examination. In case of either technical problems or anatomical barriers, ultrasonography was repeated after 5-7 days. All patients were followed up for three months for the occurrence of symptomatic DVT and/or SVT and/or pulmonary embolism.

RESULTS

We enrolled 239 patients (F: 63.6%; mean±SD age: 58.3±16.8). At the initial diagnostic work-up, DVT was detected in 24 (10%) patients while SVT in 35 (14.6%) patients. During follow-up, one upper extremity DVT was found. D-dimer levels were higher in patients with DVT than in those without. Sensitivity and specificity of D-dimer for DVT were 92% (95%CI: 73-99%) and 60% (95%CI: 52-67%) respectively, with a negative predictive value of 98% (95%CI: 93-100%), whereas for SVT they were 77% (95%CI: 59-89%) and 60% (95%CI: 52-67%) respectively, with a negative predictive value of 93% (95%CI: 86-97%).

CONCLUSIONS

D-dimer has a negative predictive value ≥93% for excluding DVT in symptomatic outpatients and it can be a useful test in the diagnostic work-up of suspected upper extremity DVT.

The mortality benefit threshold for patients with suspected pulmonary embolism

OBJECTIVES

The mortality benefit for pulmonary embolism (PE) is the difference in mortality between treated and untreated patients. The mortality benefit threshold is the mortality benefit above which testing for a condition should be initiated and below which it should not. To illustrate this concept, the authors developed a decision model to estimate the mortality benefit threshold at several pretest probabilities for low-risk emergency department (ED) patients with possible PE and compare those thresholds with contemporary management of PE in the United States and what is known and not known about treatment benefits with anticoagulation.

METHODS

The authors built a decision model of a 25-year-old female with suspected PE. Model inputs were obtained from the literature or clinical judgment when data were unavailable. One-way sensitivity analysis was used to derive the mortality benefit threshold at several fixed pretest probabilities, and two-way sensitivity analysis was used to determine drivers of the mortality benefit threshold.

RESULTS

At a 15% pretest probability, the mortality benefit threshold was 3.7%; at 10% it was 5.2%; at 5% it was 9.8%; at 2% it was 23.5%; at 1% it was 46.3%; and at 0.5% it was 92.1%. In two-way sensitivity analyses, D-dimer specificity, CT angiography (CTA)/CT venography (CTV) sensitivity, annual cancer risk, probability of death from renal failure, and probability of major bleeding were major model drivers.

CONCLUSIONS

The mortality benefit threshold for initiating PE testing is very high at low pretest probabilities of PE, which should be considered by clinicians in their diagnostic approach to PE in the ED. The mortality benefit threshold is a novel way of exploring the benefits and risks of ED-based testing, particularly in situations like PE where testing (i.e., CT use) carries real risks and the benefits of treatment are uncertain.

Venous thrombosis in emergency department: diagnosis, treatment, and disposition

AIM

The Authors describe diagnosis, treatment and therapy of deep venous thrombosis in Emergency Department following the last guidelines indications.

DISCUSSION

Deep venous thrombosis of the legs, ranges from asymptomatic, incidentally discovered emboli to massive embolism causing immediate death. Chronic sequelae of venous thromboembolism (deep venous thrombosis and pulmonary embolism) include the post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension. Acute pulmonary embolism may occur rapidly and unpredictably and may be difficult to diagnose. Diagnosis and treatment can reduce the risk of death, and appropriate primary prophylaxis is usually effective. Patients treated for acute pulmonary embolism appear to be more times as likely to die of recurrent thromboembolism in the next year.

[Individualized "minimal invasive" anticoagulation controlled with D-dimer-antigen testing - a concept]

The aim of the proposed concept is to use anticoagulant therapy in prophylaxis and therapy of thromboembolic events only to an extent that the coagulation activation is just not any longer detectable. It results an individualized anticoagulation tailored to the coagulation activation of the patient (individualized "minimal invasive" anticoagulation). Intensity and control of efficiency are to be monitored by measurement of in vivo coagulation activation, e.g. by D-dimer-antigen measurement. Especially with the use of the new oral anticoagulants such a saver anticoagulant therapy - as far as possible from bleeding risk - could open up new indications, which so far are not used because of safety reasons. More patients at risk could be prevented from thromboembolic events. The proposed concept is based on pathophysiological considerations and own clinical experience. It should be evaluated for efficiency in clinical studies.

[Clinical significance of D-dimer activity in thrombosis of patients with return of spontaneous circulation after cardiopulmonary resuscitation]

OBJECTIVE

To investigate the clinical significance of D-dimer contents in peripheral blood for monitoring the efficacy of thrombolytic therapy in patients with return of spontaneous circulation (ROSC) of cardiopulmonary resuscitation (CPR) cardiopulmonary resuscitation after cardiac arrest.

METHODS

Forty-seven patients with sudden cardiac arrest received CPR according to 2005 American Heart Association (AHA) guidelines for CPR and emergency cardiovascular care (ECC). At the early stage of ROSC, those patients underwent head and breast CT scan if they were in a state of unconsciousness and had unstable vital signs. If intracranial hemorrhage, dissection of aorta and pneumothorax were rule out, and those patients who maintained blood circulation for over 24 hours were included. The expression of D-dimer contents in peripheral blood was determined at 0, 1, 2, 4, 8, 12 h after CPR in all patients. And the patients were randomly divided into control and experiment groups. Prior to thrombolysis, the patients whose D-dimer more than 512 µg/L were classified as Group A (n = 17); those whose D-dimer below 512 µg/L Group B (n = 14); and the remaining control group whose family members refused thrombolytic therapy Group C (n = 16). The general data, Glasgow coma scale, survival rate and the change of D-dimer in peripheral blood were analyzed.

RESULTS

In Group A, D-dimer level began to increase significantly at CPR 1 hour. It peaked at CPR 2 hours then decreased gradually. The final survival rate was 67%. The survival rate and GCS were higher than those of Groups B and C. In Group B, the D-dimer concentrations began to increase gradually at CPR1 hour, peaked at CPR 12 hours and then decreased. The survival rate and GCS was lower than those of Group A and similar to those of Group C. Group C was control group with no thrombolysis.

CONCLUSION

For those ROSC patients with D-dimer concentrations significantly higher than usual, the pathogenesis of cardiac arrest may be concerned with thromboembolism, thrombosis in circulatory system and hyperviscosity. After an initiation of thrombolytic therapy, blocked blood vessels are recanalized, blood circulation improves and the cause of cardiac arrest is removed. Thus their survival rate becomes better. For those with D-dimer concentrations no higher than usual, the cause of cardiac arrest is not concerned with thromboembolism, thrombolytic therapy can not improve the patient outcome. And the final survival rate remains unchanged. The significance of thrombolytic therapy is none.

Sex, age and normal post-anticoagulation D-dimer as risk factors for recurrence after idiopathic venous thromboembolism in the Prolong study extension

BACKGROUND

The PROLONG randomized study showed that patients with an abnormal D-dimer after anticoagulation suspension for a first unprovoked episode of venous thromboembolism (VTE) benefited from anticoagulation resumption. Patients with normal D-dimer after anticoagulation suspension had a low recurrence rate (4.4% patient-years) but their anticoagulation optimal duration remained uncertain.

OBJECTIVES

To assess whether sex and age, in combination with normal D-dimer, are risk factors for VTE recurrence in patients enrolled in the PROLONG study extended follow-up.

METHODS

D-dimer was measured at 1 month after anticoagulation suspension. Patients with a normal D-dimer did not resume anticoagulants, whereas patients with an abnormal D-dimer were randomized either to resume or not anticoagulants. Primary outcome was recurrent VTE.

RESULTS

After excluding patients resuming anticoagulants for abnormal D-dimer, recurrences were higher in males than females [7.4% patient-years - 47/639 vs. 4.3% patient-years - 27/626; hazard ratio (HR) = 1.7; P = 0.027] and in patients aged 65 or older than in younger patients (8.4% patient-years - 50/598 vs. 3.6% patient-years - 24/667; HR = 2.1; P = 0.003). In patients with normal D-dimer and younger than 65, recurrences were higher in males than in females (5.1% vs. 0.4% patient-years; adjusted HR = 10.6; P = 0.023) and both females and males aged 65 years or older had more recurrences (6.6% and 8.1% patient-years, respectively, adjusted HR: 16.0; P = .008 and 16.0; P = 0.008, respectively) than females younger than 65.

CONCLUSIONS

In patients with idiopathic VTE and a normal D-dimer at 1 month after anticoagulation suspension, females younger than 65 had a very low risk of recurrence.

Relation of cardiac troponin I measurements at 24 and 48 hours to magnetic resonance-determined infarct size in patients with ST-elevation myocardial infarction

Levels of circulating cardiac troponin I (cTnI) or T are correlated to extent of myocardial destruction after an acute myocardial infarction. Few studies analyzing this relation have employed a second-generation cTnI assay or cardiac magnetic resonance (CMR) as the imaging end point. In this post hoc study of the Efficacy of FX06 in the Prevention of Mycoardial Reperfusion Injury (F.I.R.E.) trial, we aimed at determining the correlation between single-point cTnI measurements and CMR-estimated infarct size at 5 to 7 days and 4 months after a first-time ST-elevation myocardial infarction (STEMI) and investigating whether cTnI might provide independent prognostic information regarding infarct size at 4 months even taking into account early infarct size. Two hundred twenty-seven patients with a first-time STEMI were included in F.I.R.E. All patients received primary percutaneous coronary intervention within 6 hours from onset of symptoms. cTnI was measured at 24 and 48 hours after admission. CMR was conducted within 1 week of the index event (5 to 7 days) and at 4 months. Pearson correlations (r) for infarct size and cTnI at 24 hours were r = 0.66 (5 days) and r = 0.63 (4 months) and those for cTnI at 48 hours were r = 0.67 (5 days) and r = 0.65 (4 months). In a multiple regression analysis for predicting infarct size at 4 months (n = 141), cTnI and infarct location retained an independent prognostic role even taking into account early infarct size. In conclusion, a single-point cTnI measurement taken early after a first-time STEMI is a useful marker for infarct size and might also supplement early CMR evaluation in prediction of infarct size at 4 months.

FX-06, a fibrin-derived Bbeta15-42 peptide for the potential treatment of reperfusion injury following myocardial infarction

Several novel interventional and pharmacological therapeutic approaches have been examined in recent years for the prevention of ischemia/reperfusion injury in myocardial infarction; however, most approaches have failed to progress to clinical trials, and the underlying pathological mechanisms of ischemia/reperfusion injury remain poorly understood. The fibrin Bbeta chain-derived peptide FX-06, under development by Ikaria Holdings Inc, is a novel candidate in phase II trials for the prevention of ischemia/reperfusion injury. FX-06 competitively binds to vascular endothelial (VE)-cadherin, thereby inhibiting leukocyte transmigration and initiating VE-cadherin-mediated signaling, which tightens the endothelial barrier and reduces capillary leakage. The sequence of FX-06 resembles that of a physiological peptide, and the compound has been well tolerated in clinical trials. In a phase II trial in patients with acute ST-segment elevation myocardial infarction who were undergoing percutaneous coronary intervention, FX-06 significantly reduced the necrotic core zone compared with placebo. Whether FX-06 treatment can have a clinical benefit remains to be established. Nonetheless, the unique mechanism of action and short half-life that distinguish FX-06 from competitive pharmacological agents would allow its use in combination with other drugs, potentially contributing to a successful pharmacological therapy for the prevention of ischemia/reperfusion injury after decades of disappointing results.

[D-dimer dosage for the prediction of recurrent venous thromboembolism]

The optimal duration of oral anticoagulation therapy for venous thromboembolism is controversial. Recent studies focused on identifying risk factors associated with recurrent thromboembolism in order to identify patients at particularly high risk for recurrence and optimize the duration of anticoagulant treatment. Recent studies show that an elevated D-dimer level one month after stopping the initial course of anticoagulants is associated with higher risk of recurrence. Despite theses results, evidence of using D-dimer for tailoring duration of anticoagulation is still sparse.

The fibrin-derived peptide Bbeta15-42 is cardioprotective in a pig model of myocardial ischemia-reperfusion injury

OBJECTIVE

The fibrin-derived peptide Bbeta15-42 has been shown to reduce infarct size in rodent models of ischemia-reperfusion injury. To increase its potential for translation into the clinic, we studied the effects of Bbeta15-42 in pigs, whose coronary anatomy is similar to that of humans. In addition, we evaluated the pharmacokinetics and safety of Bbeta15-42 in several species, including humans.

DESIGN

Animal study and phase I trial.

SETTING

University hospital and contract research laboratories.

SUBJECTS

Pigs/healthy volunteers.

INTERVENTIONS

Male farm-bred Landrace pigs were subjected to 1 hr of left anterior descending coronary artery occlusion followed by 3 hrs of reperfusion. At the time of reperfusion, Bbeta15-42 (2.4 mg/kg, n = 6) or random peptide (control; 2.4 mg/kg, n = 6) was administered as an intravenous bolus. As a positive control, pigs were subjected to ischemic preconditioning (n = 6). Cardiac damage and hemodynamics were recorded. Biodistribution and pharmacokinetics of Bbeta15-42 were determined in rats and dogs. In a phase I trial involving 30 male healthy volunteers, pharmacokinetics and safety were tested in a randomized, double-blinded, placebo-controlled, parallel-group, single ascending dose study.

MEASUREMENTS AND MAIN RESULTS

Bbeta15-42 and ischemic preconditioning significantly reduced myocardial infarct size and troponin I levels. Bbeta15-42 also reduces interleukin-6 levels, underlining its anti-inflammatory properties. Furthermore, in humans, the pharmacokinetics of the peptide Bbeta15-42 were comparable to those of animals, and no serious adverse effects were observed.

CONCLUSIONS

Bbeta15-42 elicits cardioprotection in pigs and is clinically safe in phase I testing of humans. This study confirms the new concept of a pathogenic role of fibrin derivatives in myocardial reperfusion injury, which can be inhibited by peptide Bbeta15-42.

Rationale and Design of the ‘F.I.R.E.’ Study

Immediate reopening of acutely occluded coronary arteries via primary percutaneous coronary intervention (PCI) is the treatment of choice to salvage the ischemic myocardium in the setting of ST-segment elevation myocardial infarction (STEMI). However, the sudden re-initiation of blood flow achieved with PCI can lead to a local acute inflammatory response with further endothelial and myocardial damage. This phenomenon, described as 'reperfusion injury', has been recognized for several decades, yet no pharmacologic intervention has so far succeeded in reducing myocardial damage linked to reperfusion. FX06 is a naturally occurring peptide derived from the neo-N-terminus of fibrin (Bbeta(15-42)). It prevents leukocyte migration through the gap junctions of endothelial cells. Experimental studies have shown that FX06 inhibits the binding of the proinflammatory fibrin E1 fragment to VE-cadherin expressed in the adherence junction. It represents a novel approach to reducing local and systemic inflammation, including myocardial reperfusion injury, in the adherens junction. The present multicenter, double-blind, randomized, placebo-controlled study is designed to test the hypothesis that FX06 injection during and immediately after primary PCI can reduce infarct size in patients with STEMI. The primary outcome measure of efficacy in this study is the degree of myocardial salvage calculated as the difference between the perfusion defect before and after PCI, determined by myocardial perfusion scintigraphy during rest. Further, infarct size at the end of the index hospitalization, as well as at 4 months, will be measured by cardiac magnetic resonance imaging. The present position paper describes the rationale, design and the methods utilized in this trial.

Thromboses veineuses cérébrales : mise au point

INTRODUCTION

Although more rare than arterial thrombosis, cerebral venous thrombosis are a non-negligible cause of stroke. Characterised by the large diversity of clinical presentations and etiologies, they have a much better prognosis than arterial stroke. The evolution remains unforeseeable, with a non-negligible proportion of worsening at the acute phase and diagnosis must be early to begin as soon as possible the treatment, which is at present based on heparin therapeutics.

CURRENT KNOWLEDGE AND KEY POINTS

Neuroimaging examinations are essential for diagnosis of CVT. MR Imaging with MR venography is the key procedure. New sequences are on evaluation in CVT bringing some physiopathogical arguments (Diffusion weighted imaging) or help for diagnosis (with T2* MRI sequence). If D-dimers dosage is helpful for diagnosis of deep venous thrombosis, its interest remains to be determined during CVT.

CONCLUSION

CVT diagnosis is a challenge for the clinician. Because of the multiple causes and favorising factors, CVT are at the convergence of many specialties and could thus benefit of each one contribution for better understanding the physiopathology, improving earlier diagnosis or identifying the severe forms that could require right away more aggressive treatments than heparin. The interest of local thrombolysis or thrombectomy remains to be determined in an international randomised study.

[Diagnosis and treatment of venous thrombosis]

In the diagnosis of deep vein thrombosis in ambulatory patients, the recommended initial steps are assessment of clinical probability (CP) and a sensitive D-dimer test. With a low CP and negative D-dimer, thrombosis can be ruled out. All other constellations require further investigation with imaging techniques. Compression ultrasonography is the first-line investigation. Low-molecular weight heparin is the treatment of choice for uncomplicated venous thrombosis. Secondary prophylaxis with a vitamin K antagonist is introduced in parallel as quickly as possible. The duration of treatment depends on the exposure and predisposing factors, weighing carefully the risk of recurrence on the one hand against the risk of bleeding on the other. If there are contraindications to anticoagulation with heparins or coumarins, various other anticoagulant drugs are available.

[Acute dyspnea in the emergency room: the utility of troponin, natriuretic, procalcitonin and D-dimers]

In emergency, some "low cost" biological tests are too often systematically performed while others are not prescribed because they are considered "too expensive". Good practices for biological testing are in fact the real means for saving money. Here, in order to help for defining those good practices, we review emergency medical approach and, as an example, specify findings concerning the clinical utility of key blood analyses in patients with acute dyspnea. Emergency laboratory testing is usefull when it contributes to establish the diagnosis or to evaluate comorbidity or to stratify disease severity. In a given emergency context, clinical utility must be anticipated according to a bayesian approach with an estimation of the post-test probabilities using the likelihood ratios (estimated from literature) and the pretest probabilities (established by examination at the bedside). The likelihood ratio is the best criterion for diagnostic accuracy of a biological test. According to this criterion, troponin, natriuretic peptides, procalcitonin and D-dimers are four "costly" markers but which can significantly contribute to the etiologic diagnosis of an acute dyspnea. Troponin, natriuretic peptides and procalcitonin are also prognostic markers and are valuable parameters for stratifying disease severity according to their initial value and their plasmatic kinetic during the clinical course of the disease. In conclusion, it is not only the cost of the test but overall the potential impact of its result on the management of the patient's care which makes the decision of performing the test or not.

The fibrin-derived peptide Bβ15–42 protects the myocardium against ischemia-reperfusion injury

In the event of a myocardial infarction, current interventions aim to reopen the occluded vessel to reduce myocardial damage and injury. Although reperfusion is essential for tissue salvage, it can cause further damage and the onset of inflammation. We show a novel anti-inflammatory effect of a fibrin-derived peptide, Bbeta15-42. This peptide competes with the fibrin fragment N-terminal disulfide knot-II (an analog of the fibrin E1 fragment) for binding to vascular endothelial (VE)-cadherin, thereby preventing transmigration of leukocytes across endothelial cell monolayers. In acute or chronic rat models of myocardial ischemia-reperfusion injury, Bbeta15-42 substantially reduces leukocyte infiltration, infarct size and subsequent scar formation. The pathogenic role of fibrinogen products is further confirmed in fibrinogen knockout mice, in which infarct size was substantially smaller than in wild-type animals. Our findings conclude that the interplay of fibrin fragments, leukocytes and VE-cadherin contribute to the pathogenesis of myocardial damage and reperfusion injury. The naturally occurring peptide Bbeta15-42 represents a potential candidate for reperfusion therapy in humans.

[Obstetric complications associated with DIC. Importance of D-dimer in the diagnosis and treatment. A clinical case]

The case of a 32-year old woman with 36-week pregnancy presented at hospital because of spontaneous vaginal bleeding, anemia and mild hypotension is reported. Fetal mors in utero, abruptio placentae and diffuse intravascular coagulation were diagnosed. The patient subsequently underwent cesarean section and large retroplacental hematoma was removed and obviously fetum. The DIC was easily controlled by means of recently introduced method of determination of fibrin D-dimer.

Plasma exchange and concomitant therapy in TTP

Since plasma exchange was introduced in the management of thrombotic thrombocytopenic purpura (TTP) in 1977, patient survival rate has increased from 10 to 80%. However, approximately 50 subsequent case reports in the literature provide no consensus as to the optimal therapy. We review here 4 episodes of TTP in 3 patients. In all cases, treatment was started with intensive FFP plasma exchange combined with administration of antiplatelet agents and corticosteroids. Remission was achieved in 3 out of 4 episodes although all required individualization of the medication regimen. In the remaining patient, cytotoxic therapy (vincristine) and ultimately splenectomy were required to achieve stable remission. The variable clinical response to these therapeutic protocols indicates that TTP may not represent a single homogeneous disease entity but rather may involve various underlying pathologies. We conclude that the most effective present therapy for the management of TTP is daily plasma exchange with fresh frozen plasma infusions combined with antiplatelet agents and steroids. Vincristine and splenectomy should only be employed if this protocol proves ineffective.

Severe glomerulonephritis complicated by coagulopathy: treatment with anticoaguland and immunosuppresive drugs

Serial determinations, using plasma fibrinogen gel chromatography as well as standard methodology, demonstrated that six children with severe glomerulonephritis, characterized on renal biopsy by glomerular necrosis and crescent formation, had persistent evidence of intravascular coagulation. Based on these observations, therapy with anticoagulants and azathicoagulants and azathioprine was instituted for one year; treatment with anticoagulants was continued for a second year. Anticoagulant therapy was initiated with heparin, followed by oral anticoagulation with phenindione and dipyridamole. In contrast to our earlier experience with similar patients, each of the present patients improved. Urinalyses returned to normal and glomerular filtration rates to near normal values in all patients at the end of the treatment period and have remained so for up to 3.9 years since treatment has been completed. Post-treatment biopsies showed remarkable improvement, with virtually no glomerulosclerosis even in patients who had had a high incidence of glomerular crescents before treatment. It is suggested that the therapeutic regimen favorably influenced the natural history of disease and that plasma fibrinogen chromatographic findings may be helpful in selecting patients likely to benefit from the use of anticoagulant therapy.