TO THE EDITOR:
In "Prevention of Deep-Vein Thrombosis after Total Hip Arthroplasty. Comparison of Warfarin and Dalteparin" (79-A: 1365—1372, Sept. 1997), Francis et al. reached several well documented conclusions. They found a lower rate of deep-vein thrombosis but a higher rate of transfusion and bleeding complications among the patients who received dalteparin.
Francis et al. did not mention the development of any late deep-vein thrombosis, and the venographies were performed at a mean (and standard deviation) of 7 ± 2 days postoperatively. As patients are at increased risk for deep-vein thrombosis for more than one week after total hip replacement, it would be useful to know the rate of deep-vein thrombosis during the follow-up period. Did deep-vein thrombosis occur after the venograms were performed?
Also, the method for the diagnosis of pulmonary embolism is mentioned on page 1367 but there is no mention of the rate of pulmonary embolism in the treatment groups. As pulmonary embolism is the most dreaded complication of deep-vein thrombosis, the prevalence of this complication in the treatment groups is of great interest.
Kim J. Chillag, M.D.: The Moore Orthopaedic Clinic, 1 Richland Medical Park, Suite 110, Columbia, South Carolina 29203
Dr. Francis, Dr. Pellegrini, Dr. Totterman, Dr. Boyd, Dr. Marder, Ms. Liebert, Dr. Stulberg, Dr. Ayers, Dr. Rosenberg, Dr. Kessler, and Dr. Johanson reply:
We appreciate the questions raised by Dr. Chillag regarding our study. Clinical symptoms consistent with pulmonary embolism developed in thirteen patients who had received dalteparin and in six who had received warfarin, but the diagnosis was confirmed by ventilation-perfusion lung-scanning in only two patients in each treatment group. Thus, the prevalence of pulmonary embolism was the same in both groups. We agree that deep-vein thrombosis can occur after discharge from the hospital, but long-term follow-up was not a part of this study.
Charles W. Francis, M.D.; Saara Totterman, M.D.; Allen D. Boyd, Jr., M.D.; Victor J. Marder, M.D.; Kristin M. Liebert, M.A.: Vascular Medicine Unit, P.O. Box 610 (C. W. F., V. J. M., and K. M. L.) and Departments of Radiology, P. O. Box 6944 (S. T.) and Orthopaedics, P.O. Box 665 (A. D. B., Jr.), University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, New York 14642
Vincent D. Pellegrini, Jr., M.D.: Department of Orthopaedics and Rehabilitation, The Milton S. Hershey Medical Center, P.O. Box 850, Hershey, Pennsylvania 17033
Bernard N. Stulberg, M.D.: Cleveland Center for Joint Reconstruction, St. Vincent Charity Hospital, 2322 East 22nd Street, Suite 102, Cleveland, Ohio 44115
David C. Ayers, M.D.: Department of Orthopedic Surgery, State University of New York Health Science Center at Syracuse, 550 Harrison Center, Suite 100, Syracuse, New York 13202
Aaron Rosenberg, M.D.: Department of Orthopaedic Surgery, Rush-Presbyterian-St. Luke's Medical Center, 1725 West Harrison Street, Suite 1063, Chicago, Illinois 60612
Craig Kessler, M.D.: Lombardi Cancer Center, Georgetown University Medical Center, 3800 Reservoir Road, N.W., Washington, D.C. 20007
Norman A. Johanson, M.D.: Department of Orthopaedic Surgery, Temple University School of Medicine, 3401 North Broad Street, Philadelphia, Pennsylvania 19140