Book Review

Prevention of Venous Thromboembolism

Thrombosis, Embolism and Bleeding

N Engl J Med 1993; 329:739-740September 2, 1993

Article

Prevention of Venous Thromboembolism
(Fundamental and Clinical Cardiology [12].) Edited by Samuel Z. Goldhaber. 607 pp. New York, Marcel Dekker, 1993. $95. ISBN: 0-8247-8757-9

Thrombosis, Embolism and Bleeding
(Current Issues in Heart Valve Disease.) Edited by Eric G. Butchart and Endre Bodnar. 495 pp., illustrated. London, ICR, 1992. $140. ISBN: 1-872743-04-8

Physicians from all medical specialties are united in a common goal of preventing, diagnosing, and treating venous thromboembolism. The 25 chapters in Prevention of Venous Thromboembolism address these issues as they pertain to both medical and surgical patients. The first section, “Fundamental Considerations for Venous Thromboembolism,” includes an excellent chapter on the economic burden of the problem. It emphasizes the economic justification for primary prophylaxis against thrombosis by pointing out that the use of prophylaxis in each 1 million patients undergoing surgical procedures reduces health care costs by $60 million. Another chapter explains the sonographic examination of the deep venous system of the lower extremities and provides excellent diagrams of the test procedures as well as of the anatomy of the deep venous system. The latter is especially helpful for those who do not know that the “superficial” femoral vein is really a vein of the deep venous system and that some of the veins are duplicated in a high percentage of patients.

The second section, on “prevention modalities,” contains chapters on dextran, heparin, warfarin, low-molecular-weight heparin, and dermatan sulfate. Two chapters provide an informative and practical discussion of the principles and uses of both compression devices in the perioperative period and filters to interrupt the inferior vena cava. The chapter on low-molecular-weight heparin contains an excellent review of a class of drugs that may soon be widely available, whereas the chapters on dextran and dermatan sulfate are more reflective of the authors' enthusiasm for these drugs than of their therapeutic value. The discussions of heparin and warfarin are disappointingly brief, and do not address in sufficient detail heparin-associated thrombocytopenia or the medications and clinical conditions that can affect the monitoring of warfarin or heparin. The book misses an excellent opportunity to explain the concept and use of the international normalized ratio for monitoring patients undergoing long-term anticoagulation with warfarin.

The third section, “Specific Prevention Strategies,” focuses on perioperative prophylaxis for patients undergoing orthopedic or gynecologic surgery, coronary-artery bypass grafting, neurosurgery, or obstetrical procedures. Each of its chapters contains excellent references defining the risk of venous thromboembolism in specific surgical situations and clearly outlines the best approaches for prophylaxis based on the patients' underlying risk factors for thrombosis. The value of graduated compression stockings and intermittent pneumatic compression either alone or in combination with warfarin is emphasized throughout the book.

A final section provides practical advice on how to establish a uniform hospital-based system for prophylaxis according to the stratification of patients' risk factors. A highlight of this section is a thorough discussion of the cost effectiveness of preventing venous thromboembolism in a variety of clinical settings.

In the mid-1800s, the pathologist Rudolf Virchow elucidated three conditions that result in venous thrombosis: stasis, endothelial-cell damage, and hypercoagulability. His theory is mentioned frequently throughout the book; however, the references to his work could have been embellished by the addition of a summary of the recent advances in our understanding of the role of both the endothelium and expression of tissue factor in initiating thrombosis and the inhibitors that regulate hemostasis.

This book provides an excellent, practical approach to the prevention and treatment of venous thromboembolism. The chapters are very well referenced and are a convenient source of information for physicians involved with the practical therapeutic issues of venous thrombosis, in either a primary or consultative role.

By the end of the century 2 million patients worldwide will have prosthetic heart valves; currently, as many as 75 percent of the complications in patients with cardiac valves are related to thrombosis, embolism, and anticoagulant-associated bleeding. The scope of this problem and the relatively recent development of methods to standardize oral anticoagulation prompted the editors of Thrombosis, Embolism and Bleeding to develop a cohesive work on thromboembolic and anticoagulant-associated bleeding complications in patients with valvular heart disease.

The goal of the book is accomplished in six major sections, the first of which discusses topics ranging from the contribution of patient-related factors, such as nonvalvular atrial fibrillation, to the risk of thromboembolism in patients with prosthetic cardiac valves. This section thoroughly reviews the recent trials of anticoagulation in atrial fibrillation. The second section deals with the influence of prosthesis-related factors on thromboembolism and the use of transesophageal ultrasonography to detect valvular thrombosis. A section on the postoperative care of patients with cardiac valves contains seven chapters that provide a thorough discussion of the monitoring of warfarin according to the international normalized ratio. The section also reviews the pharmacology and potential role of antiplatelet agents such as aspirin, dipyridamole, and ticlopidine in conjunction with oral anticoagulants in the prevention of thromboembolism.

Additional sections cover the prevention of thromboembolism in subgroups of patients with prosthetic valves, such as pregnant women, the elderly, children, and those who have had a complication such as a stroke or anticoagulant-related bleeding. A final section describes methods of data analysis that can be used for clinical studies to determine the risk of embolism in patients with prosthetic valves and provides a critique of the literature.

The authors review what is known about the medical aspects of the treatment of patients with artificial cardiac valves. For example, in some subgroups the use of a platelet inhibitor in combination with warfarin at a low intensity may be superior to the use of warfarin alone at a higher intensity. They emphasize that in patients with artificial cardiac valves and thromboembolism, the source of the thrombus is usually not valvular, and they describe how the management of this complication differs from that of valvular thrombosis.

The authors also make concrete recommendations based on the available information and their clinical experience. An example is the discussion of the regulation of perioperative anticoagulation in patients with artificial cardiac valves who are undergoing noncardiac surgery. In writing about this issue, the author includes an analysis of the cost effectiveness of different strategies.

Each chapter has an extensive bibliography, and the book is scholarly yet highly readable. The authors are leaders in their fields, and their writing reflects their depth of clinical experience as well as a thorough command of the literature. The extensive efforts of the editors are reflected in the cross-referencing among chapters, the lack of redundancy, and the uniform approach to well-defined clinical problems. By including authors from the United Kingdom, the United States, Germany, the Netherlands, Belgium, South Africa, and Israel, the editors have ensured that the book will have broad international appeal. It is a valuable reference for any physician in a surgical or medical specialty who cares for patients with valvular heart disease or who is responsible for monitoring oral anticoagulation.

Barbara Alving, M.D.
Walter Reed Army Institute of Research, Washington, DC 20307-5100