A European view on the North American fifth consensus on antithrombotic therapy

Effect of percutaneous transvenous mitral commissurotomy on left atrial appendage function: an immediate and 6-month follow-up transesophageal Doppler study

BACKGROUND

The left atrial appendage (LAA) is a common site of thrombus formation and is the source of systemic thromboembolism in patients with rheumatic mitral stenosis. LAA contractile dysfunction is a common finding in these patients. The aim of this study was to assess immediate and 6-month follow-up LAA function by transesophageal Doppler echocardiography in patients who underwent percutaneous transvenous mitral commissurotomy (PTMC).

METHODS

Forty-seven consecutive patients with symptomatic critical mitral stenosis who underwent PTMC were enrolled. All had underwent transthoracic and transesophageal echocardiography before, 24 hours after, and 6 months after PTMC. Pulse Doppler velocities of the LAA were measured, including peak early diastolic (E wave), peak late diastolic (A wave), and peak systolic (S wave). The corresponding tissue Doppler velocities of the LAA, including peak early diastolic (E(LAA)), peak late diastolic (A(LAA)), and peak systolic (S(LAA)), were also measured. LAA ejection fraction was measured using the modified Simpson's method.

RESULTS

The mean age of the 47 enrolled patients was 31.7 ± 10.26 years. Thirty-eight patients were in sinus rhythm, and the remaining nine were in atrial fibrillation. PTMC was successful in all patients. The pulse Doppler velocities of the LAA at baseline, after PTMC, and at 6-month follow-up were as follows: for the E wave, 15.29 ± 2.26, 17.02 ± 2.25, and 17.97 ± 2.55 cm/sec, respectively (P < .001); for the A wave 22.45 ± 4.11, 24.19 ± 4.21, and 25.99 ± 4.51 cm/sec, respectively (P < .001); and for the S wave, 28.52 ± 4.37, 31.45 ± 5.37, and 33.06 ± 4.99 cm/sec, respectively (P < .001). The corresponding tissue Doppler velocities of LAA were as follows: for E(LAA), 4.65 ± 0.91, 5.28 ± 0.85, and 5.80 ± 0.84 cm/sec, respectively (P < .001); for A(LAA), 6.67 ± 1.12, 7.33 ± 1.17, and 7.88 ± 1.22 cm/sec, respectively (P < .001); and for S(LAA), 4.67 ± 1.12, 5.52 ± 1.18, 6.07 ± 1.11 cm/sec, respectively (P < .001). There was a nonsignificant increase in LAA ejection fraction (48.97 ± 8.14% vs 52.3 ± 13.76% vs 52.11 ± 16.3%, respectively, P = .052). On subgroup analysis between patients in sinus rhythm and those with atrial fibrillation, there was no significant difference for LAA ejection fraction and pulse and tissue Doppler velocities. Very good intraclass correlation of the LAA parameters was also observed for the reproducibility of the data.

CONCLUSIONS

The present study shows contractile dysfunction of the LAA in patients with critical mitral stenosis, which significantly improved after PTMC, and a further improvement was observed at 6-month follow-up. Favorable 6-month improvements in LAA parameters suggest continuous structural remodeling of the LAA after PTMC, which is clinically attributed to the absence of thromboembolism. Although there was an improvement in LAA function, it was far below the normal range, suggesting a need for continuous long-term monitoring and management of thromboembolism in these patients.

Multiplex assay for genetic testing of thrombophilia: a method for routine clinical care

There is an increasing demand for genetic testing of patients with hypercoagulability. We have developed a multiplex-polymerase chain reaction (PCR) technique that incorporates the state-of-the art of genetic testing for thrombosis mutations (Factor V Leiden [FVL] and G20210A F2 and C46T F12). The sequences are detected by enzyme-linked immunosorbent assay (ELISA)-resolved colorimeter after hybridization with an amplification product labeled with digoxygenin. To evaluate the reliability of this method, we analyzed 122 deoxyribonucleic acid (DNA) samples of known genotypes for these three mutations. Six subjects initially assigned as heterozygous for FVL and two subjects assigned as normal for the G20210A F2 mutation showed discrepancies between the current techniques and our newly-developed ELISA-based technique. When these samples were sequenced the concordance using our method was 100%. Thus, initially they were assigned incorrectly based on the available methodologies. It is noteworthy that our method is adaptable to an Automated ELISA Analyzer that allows for routine processing of both small and large numbers of DNA samples. We present a robust, rapid, reproducible, cost-effective, and simple multiplex PCR ELISA method to simultaneously detect carriers of thrombotic genetic risk factors. Testing for thrombophilia should contribute to better diagnosis, prevention, and treatment strategies, providing valuable information to assess the risk of recurrence in the proband, and in family members who are asymptomatic.

The obstetrical patient with a prosthetic heart valve

Definitive recommendations on anticoagulation strategy in pregnant women who have prosthetic heart valves are lacking because of the paucity of prospectively collected data. The use of warfarin, UFH, LMWH, or any combination of these choices has potentially adverse outcomes for the mother and fetus. Although there is no treatment option that has proven to be completely satisfactory, there is agreement that failures are most often due to underdosing and the lack of intensive monitoring of anticoagulation. A careful discussion with the patient must be undertaken so that she and the clinician can come to a decision about the most appropriate protocol.

[Can home prophylaxis for venous thromboembolism reduce mortality rates in patients with chronic obstructive pulmonary disease?]

OBJECTIVE

The incidence of venous thromboembolism (VTE) in patients with chronic obstructive pulmonary disease (COPD) ranges from 20% to 60% in different studies and the mortality rates are higher for patients with both conditions. Heparin prophylaxis is therefore usually prescribed for COPD patients who are hospitalized for exacerbation. Once their situation becomes stable, however, they are discharged to home without prophylaxis even though the low level of physical activity their disease allows continues to put them at risk for VTE. The aim of this study was to test the efficacy of home heparin prophylaxis on reducing the incidence of VTE and on the overall mortality rate in patients with severe COPD.

PATIENTS AND METHODS

We conducted a prospective, randomized controlled trial of 87 patients with severe COPD who required home oxygen therapy (> or =18 h/d) and whose physical activity was highly restricted. A total of 44 patients received low molecular weight heparin (3500 IU/d of bemiparin) subcutaneously for 6 months. The outcome measures were incidence of VTE and mortality at 3 and 6 months.

RESULTS

Four patients (9.1%) died in the heparin group and 9 (20.4%) died in the control group; the difference was not statistically significant (P=.23). VTE without pulmonary embolism developed in 1 patient (2%) in each group. Slight bleeding complications appeared in 9 patients (20.4%) in the heparin group and 1 patient (2.3%) in the control group, a difference that was statistically significant (P=.015).

CONCLUSIONS

Home prophylaxis with heparin does not reduce the incidence of VTE or overall mortality in patients with severe COPD.

Prevention of postoperative venous thromboembolism. Risk assessment and methods of prophylaxis

PURPOSE

To describe risk assessment models that have been developed to stratify patients into different risk levels of postoperative venous thromboembolism (VTE) and then to review the different methods of prophylaxis and to outline the evidence supporting their effectiveness and safety.

SOURCE

Our review of the literature is focused on consensus documents, recent large randomized trials and meta-analyses.

PRINCIPAL FINDINGS

The risk of VTE is determined by the type of surgery and underlying patient factors. Risk assessment models are useful in stratifying patients into different VTE risk levels. However, multiple risk factors are often present in the same patient and in practice the evaluation of their relative contribution to the overall risk remains difficult. A variety of prophylactic strategies including physical and pharmacological methods have been shown to be effective in different patient groups. Patients with a moderate or high risk of VTE should receive prophylaxis consisting of an antithrombotic agent, unless contraindicated, used alone or in combination with a mechanical method. Recommendations concerning which prophylaxis to use and how intensive it should be are based mainly on data from trials using surrogate endpoints, and do not translate easily into practical decisions aiming to reduce the incidence of symptomatic events.

CONCLUSION

Although risk assessment models and recommendations provided by consensus documents are of practical assistance, a decision concerning any patient is best made by combining recommendations of the literature with clinical judgment, including individual patient risk factors for thrombosis and bleeding.

L’agrégation plaquettaire et ses inhibiteurs dans les syndromes coronariens aigus

Antiplatelet agents are the cornerstone therapy of acute coronary syndromes. In the setting of ST elevation myocardial infarction, antiplatelet therapy prevent the prothrombotic effect of reperfusion therapy including thrombolysis and primary percutaneous coronary intervention. In non ST-elevation acute coronary syndromes, antiplatelet therapy prevent s complete coronary thrombotic occlusion and therefore the occurrence of ST elevation myocardial infarction. Antiplatelet agent benefit is related to the patient's risk profile. It is well established that combined antiplatelet therapy is the most effective in high risk patients. Several important issues have to be faced including the identification of non responders, dose adjustment and the management of temporary interruption of antiplatelet agents in stable coronary artery disease patients.

Inherited and acquired thrombophilias and poor pregnancy outcome: should we be treating with heparin?

PURPOSE OF REVIEW

The most important acquired thrombophilia related to poor pregnancy outcome is probably antiphospholipid syndrome. Inherited thrombophilias that have been implicated in venous thromboembolism and poor pregnancy outcome and for which standard tests are generally available are antithrombin III deficiency, the factor V Leiden mutation, prothrombin G20210A mutation and the C677T polymorphism in the methylenetetrahydrofolate reductase system implicated in mild hyperhomocysteinaemia. The management of antiphospholipid syndrome with previous fetal losses is well documented and substantiated by small clinical trials. It is the purpose of this review to investigate new contributions to this field since June 2002.

RECENT FINDINGS

Only one randomized trial was published during the review period, but a Cochrane review and several excellent review articles appeared detailing management.

SUMMARY

There is a dire lack of randomized trials in the literature on the efficacy of heparin or other coagulation modulators on pregnancy outcome in patients with inherited thrombophilias. There is consensus on thrombo-prophylaxis for antiphospholipid syndrome. Protocols for the management of venous thromboembolism and pulmonary emboli related to pregnancy are well established.

The evolution and impact of the American College of Chest Physicians consensus statement on antithrombotic therapy

The evolution of the American College of Chest Physicians consensus on antithrombotic therapy is reviewed, specifically with regard to the prevention and treatment of venous thromboembolism and the rules of evidence applied. A perspective on the impact of the recommendations is offered.

Thromboprophylaxis and thrombosis in medical, surgical, trauma, and obstetric/gynecologic patients

The International Consensus and the ACCP Sixth Consensus had a great impact on the clinical acceptance of LMWHs. These recommendations have been instrumental in initiating further clinical trial to answer key questions regarding thromboprophylaxis and in setting a new standard for patient care. Also, the key to cost containment in management of DVT/PE is to (1) define the etiology (blood coagulation protein or platelet defect), institute appropriate long-term therapy as indicated, and assess appropriate family members as indicated if a hereditary defect is found and (2) use LMWH as inpatient management. saving a minimum of 210,000.00 dollars per 1000 patients simply from cost savings of recurrence, saving 17 lives per 1000 patients, and saving exorbitant costs of care for patients with recurrence and development of chronic venous insufficiency. The use of outpatient LMWH will save 4,900,000.00 dollars per 1000 patients if applied to the 70% of patients with DVT who fit the criteria of no comorbid condition requiring hospitalization and who arrive early enough to allow a diagnosis to be sent home or hospitalized for 24 hours or less. The simple defining of defects leading to unexplained thrombosis will add another 3,000,000.00 dollars in savings per 1000 patients with DVT and approximately 350,000.00 dollars per 100 patients with thrombotic stroke. In those with transient ischemic attacks, defining the defect and instituting appropriate antithrombotic therapy, thereby potentially saving approximately 30% from developing a thrombotic stroke, amounts to approximately 350,500.00 dollars (= 30% of 1,168,500.00 dollars) in savings per 100 patients.

Use of the low-molecular-weight heparin nadroparin during pregnancy. A review

Antithrombotic therapy is often used during pregnancy for the treatment and prevention of venous thromboembolism, the prevention of systemic embolism in patients with heart valve prostheses and the prevention of foetal loss in patients with antiphospholipid syndrome. Low-molecular-weight heparins (LMWHs), including nadroparin, have largely replaced unfractionated heparin as the anticoagulant of choice. The use of the LMWH nadroparin in pregnant women at an increased risk of thromboembolism or foetal loss is discussed in this review. Deep vein thrombosis can be effectively treated or prevented with nadroparin without any serious adverse events. Nadroparin 0.1 ml/10 kg s.c. once daily prevents thromboembolic complications in pregnant women with heart valve prostheses. Nadroparin is also effective in preventing foetal loss, through contributing to normal placental development and in decreasing the risk of premature delivery in pregnant women with antiphospholipid syndrome or women with herpes and antiphospholipid syndrome. These results demonstrate nadroparin is effective, easy to administer and associated with a low incidence of foetal and maternal complications. The use of nadroparin at a prophylactic dose of 0.3 ml (2850 IU AXa, 95 IU/kg) (for high-risk patients, 0.3-0.6 ml) s.c. once daily, and a therapeutic dose of 0.1 ml/10 kg (95 IU/kg) s.c. twice daily, is in line with the latest international guidelines of the American College of Chest Physicans.

Effects of Enoxaparin and Nadroparin on Major Cardiac Events in High-risk Unstable Angina Treated With a Glycoprotein IIb/IIIa Inhibitor

Clinical trials have reported the beneficial effects of platelet glycoprotein (GP) IIb/IIIa receptor antagonists and low-molecular-weight heparins (LMWH) on major cardiac events (MACE) in patients presenting with unstable angina or non-ST elevation myocardial infarction. A number of studies have documented the significant superiority of low-molecular-weight heparins, especially enoxaparin, over unfractionated heparin in the treatment of acute coronary syndromes. The purpose of this study was to compare the effects of two different LMWHs, enoxaparin and nadroparin, accompanied by platelet GP IIb/IIIa inhibition on MACE in high-risk unstable angina. The study was designed as an open-label and observational study. Sixty-eight patients presenting with unstable angina associated with high-risk criteria were randomly assigned to treatment with enoxaparin plus tirofiban (36 patients, mean age 57 +/- 11) or nadroparin plus tirofiban (32 patients, mean age: 58 +/- 8). In-hospital MACE including acute myocardial infarction (AMI), recurrent refractory angina, death, stroke, and urgent revascularization were compared between the study groups. Patient characteristics and durations of LMWH and tirofiban treatments were not different between the study groups. Coronary artery risk factors, except family history (which was observed more frequently in the enoxaparin group, P = 0.02), were also similar. MACE between the enoxaparin and nadroparin groups including AMI (5.5%, 6%), recurrent refractory angina (19%, 12%), death (0%, 3%), stroke (was not observed in either group), urgent revascularization (14%, 12%) and total MACE (19%, 15%) were not different. Enoxaparin and nadroparin, accompanied by GP IIb/IIIa inhibitor therapy, have similar effects on the development of major cardiac events in patients presenting with unstable angina and high-risk characteristics.

Enoxaparin: an update of its clinical use in the management of acute coronary syndromes

Enoxaparin (enoxaparin sodium) is a low molecular weight heparin (LMWH) indicated for use in the treatment of ischaemic complications of unstable angina and non-Q wave myocardial infarction (MI). Unfractionated heparin (UFH) has for many years represented the standard in anticoagulant therapy for patients with acute coronary syndromes; however, recent studies suggest that enoxaparin is also a viable option for anticoagulant therapy in these patients. The ESSENCE (Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q wave Coronary Events) and the TIMI 11B (Thrombolysis in Myocardial Infarction) studies reported that twice daily enoxaparin was significantly more effective than a continuous infusion of UFH in reducing the composite triple endpoint of death, MI, or recurrent angina or urgent revascularisation. Follow-up of both patient populations showed continued benefit associated with enoxaparin. Enoxaparin has been compared with tinzaparin in the treatment of unstable coronary artery disease using a nonblind study design. There was no difference between treatment groups in the therapeutic endpoints. Three nonblind studies have also compared the effects of enoxaparin and UFH in patients receiving thrombolytic therapy following acute MI. The HART II (Heparin and Aspirin Reperfusion Therapy), the ASSENT 3 (Assessment of the Safety and Efficacy of a New Thrombolytic Regimen) and the ENTIRE-TIMI 23 (Enoxaparin and Tenecteplase with or without glycoprotein IIb/IIIa Inhibitor as Reperfusion strategy in ST Elevation MI - Thrombolysis in Myocardial Infarction) studies have revealed that enoxaparin in combination with alteplase or tenecteplase is at least equivalent (HART II and ENTIRE-TIMI 23), and possibly superior (ASSENT 3) to UFH. Enoxaparin is administered as a twice-daily subcutaneous injection. In contrast, UFH is administered as an intravenous infusion which requires routine monitoring of the activated partial thromboplastin time to ensure adequate levels of anticoagulation are maintained. During the acute phase of the the ESSENCE and TIMI 11B studies, the incidence of major bleeding was similar in patients receiving enoxaparin to that in patients receiving UFH. In contrast, the rates of minor bleeding were higher in patients receiving enoxaparin than in those receiving UFH throughout these studies.

CONCLUSIONS

Data from the ESSENCE, TIMI 11B and ASSENT 3 studies have prompted calls for those LMWHs which have been shown to be superior to UFH, to be considered as first choice treatment for anticoagulation in unstable coronary syndromes. To date, these suggestions are not reflected in current guidelines which consider UFH and LMWHs equally. Irrespective, the clinical data reported in this review support the use of enoxaparin in the treatment of acute coronary syndromes. These data suggest that enoxaparin shows certain clinical and practical advantages over standard treatment with UFH and represents an important development in the treatment of acute coronary syndromes.

Long term complications of inferior vena cava thrombosis

AIM

To evaluate the long term outcome after paediatric inferior vena cava (IVC) thrombosis.

METHODS

A combined retrospective and prospective study on infants and children with IVC thrombosis treated at Aachen and Maastricht University Hospitals between 1980 and 1999.

RESULTS

Forty patients were enrolled, including four with preceding cardiac catheterisation, 18 with central venous saphenous lines, and an additional eight with umbilical venous catheters. Six patients died within three months of diagnosis; one patient was lost to follow up. Twelve of the remaining 33 patients had suffered from limited IVC thrombosis; during follow up (for up to nine years) none showed persisting caval obstruction (successful thrombolysis, n = 2; spontaneous recanalisation, n = 10). The remaining 21 patients presented with extensive IVC thrombosis. During follow up (for up to 18 years) complete restitution was found in only four cases (one thrombolysis, two surgery, one spontaneous recanalisation). Persisting iliac and/or caval venous obstruction occurred in 17 patients, including six with thrombolysis. Varicose veins were found in 12, and post-thrombotic syndrome in seven of these cases. According to Kaplan-Meier analysis, 30% of patients with persisting venous disease will develop post-thrombotic syndrome within 10 years of the thrombotic event.

CONCLUSIONS

Infants and children with extensive IVC thrombosis are at high risk for persisting venous disease and serious long term complications. Prospective trials are urgently needed to establish effective treatment strategies and to improve long term prognosis. Central venous catheters, contributing to IVC thrombosis in the majority of cases reported here, should be inserted only if essential.

Prevention of venous thromboembolism: recommendations based on the International Consensus and the American College of Chest Physicians Sixth Consensus Conference on Antithrombotic Therapy

The primary purpose of a Consensus Conference is to provide informed guidance on treatment decisions, assisting clinicians to make the optimal therapeutic choice for the patient, and providing protection against unjustified malpractice actions. The First American College of Chest Physicians (ACCP) Consensus Conference took place in 1985 and, using a systematic approach, provided recommendations for anti-thrombotic therapy based on published studies, and graded those recommendations on the level of clinical evidence. The European Consensus Conference was convened in 1991 to build on this process. During this period, the main developments included the introduction and widespread use of new thromboprophylactic agents such as low-molecular-weight heparins, and improved risk assessment, including an awareness that outpatients and general medical patients may also be at risk. Subsequently, the recommendations have been carefully reviewed and updated by experts who represent the extensive range of opinions in the field. The latest International Consensus Statement was published in 1997, and the most recent ACCP Consensus in 2001 and they provide extensive practice guidelines in the management of venous thromboembolism.

Twenty years' experience with the Medtronic Hall valve

OBJECTIVE

To assess the performance of the Medtronic Hall valve (Medtronic, Inc, Minneapolis, Minn) in one institution over a 20-year period.

METHODS

Since 1979, Medtronic Hall valves have been used in 1766 procedures (736 aortic, 796 mitral, and 234 double). Patients were followed up prospectively at 6- to 12-month intervals for a total of 12,688 follow-up years. Anticoagulation data (international normalized ratio) were recorded for all patients (approximately 95,000 observations).

RESULTS

Linearized rates of valve-related late death for aortic, mitral, and double valve replacement were 0.8%/y, 0.9%/y, and 1.1%/y, respectively. Risk factors for late mortality were (relative risk) diabetes (1.9), decade of age (1.6), concomitant coronary artery bypass grafting (1.4), hypertension (1.3), non-sinus rhythm (1.3), large valve size (1.1), valve regurgitation (1.3), and male sex (1.2). For aortic, mitral, and double valve replacement, linearized rates (percent per year) of adverse events were valve thrombosis 0.04, 0.03, and 0.0; all thromboembolism 2.3, 4.0, and 3.4; stroke 0.6, 0.8, and 0.6; major hemorrhage 1.2, 1.4, and 1.6; and prosthetic endocarditis 0.4, 0.4, and 0.7. Risk factors for thromboembolism were (relative risk) mitral valve replacement (1.9), diabetes (1.8), hypertension (1.5), and history of embolism (1.4).

CONCLUSION

At 20 years the Medtronic Hall valve demonstrates excellent durability, good hemodynamic performance, and very low thrombogenicity, with a valve thrombosis rate lower than those reported for bileaflet designs. With this prosthesis, both survival and thromboembolic events are predominantly determined by patient risk factors.