Today's News

Sunday, February 25, 1996

Study finds venography reduces anticoagulant need

Routine blood clot screening utilizing contrast venography reduces total joint replacement patients' exposure to outpatient antico-agulation therapy and the related risk of potentially life-threatening hemorrhage, according to scientific paper 242.

In the hospital, total joint replacement patients are treated prophylactically with anticoagulants to help prevent deep venous thrombosis (DVT), a potential complication of the surgery. The questions is whether this medication is discontinued at hospital discharge.

"The duration of in-hospital prophylaxis for thromboembolic disease is now much shorter due to decreased lengths of hospital stay (average: 3-5 days)," said co-author Vincent D. Pellegrini Jr., MD, who presented the findings Saturday.

Untreated DVT can result in a detached blood clot fragment traveling to a pulmonary artery, obstructing it, and causing pulmonary embolism.

"The high-risk period for development of DVT extends past 10 postoperative days," said Dr. Pellegrini. "However, due to the side effects, anticoagulants should not routinely be continued with all patients after hospital discharge."

Venography is an effective method for determining who should continue on the anticoagulant therapy, he said.

The procedure X-rays the person's veins after they are injected with a contrast medium; any blood clots in the veins will show up on the venogram.

Although invasive, venography is more accurate than ultrasound in detecting DVT, Dr. Pellegrini said. "Ultrasound is insensitive as a screening test to identify calf vein thrombi in the asymptomatic postoperative orthopaedic patient," Dr. Pellegrini said.

Orthopaedic researchers studied 1,638 patients (average age: 65.5 years) who underwent total hip or knee arthroplasty between 1984 and 1992 at the University of Rochester Strong Memorial Hospital; 546 patients had contrast venography; 1,092 patients did not have the screening.

In the study, venography identified a 24 percent overall incidence of DVT after total joint arthroplasty in patients receiving in-hospital warfarin prophylaxis.

"There were no hospital readmissions among the 131 patients diagnosed with venographic-evident DVT and treated on outpatient warfarin therapy," said Dr. Pellegrini.

In contrast, 14 of the 1,092 patients who did not receive venography screening were readmitted to the hospital.

Compared to patients with known calf DVT (who were treated with warfarin), five of 33 patients with untreated calf DVT suffered complications of thromboembolic disease, Dr. Pellegrini said.

Twelve patients who did not have venography and six patients who did have the screening had a bleeding episode.

"Venography helps to prevent the late complications of thrombo-embolic disease and the related hospital readmission," said Dr. Pellegrini. "It also is a cost-effective management strategy compared to putting all patients on extended warfarin prophylaxis."

Results of the study shows that routine unilateral screening veno-graphy, selective treatment for DVT diagnosis, and readmission for complications of thromboembolic disease or bleeding on warfarin therapy cost $827 per patient compared to $1,187 for routine extended warfarin prophylaxis for all patients after discharge without venogram surveillance.

Dr. Pellegrini is professor and chairman, department of orthopaedics and rehabilitation, Pennsylvania State University, Milton S. Hershey Medical Center, Hershey, Pa.

Co-authors of the study with Dr. Pellegrini are Diane Clement, RN, CRNA, and Carol Lush-Ehman, both from the department of orthopaedics, and Saara Totterman, MD, department of radiology, University of Rochester, Strong Memorial Hospital, Rochester, N.Y.; and Greg S. Keller and C. McCollister Evarts, MD, both from the department of orthopaedics and rehabilitation, Pennsylvania State University, Milton S. Hershey Medical Center, Hershey, Pa.