Laird Harrison

March 12, 2014

NEW ORLEANS — Combining statins with standard blood clot prevention therapies could cut the risk for venous thromboembolic events in half after total joint replacement surgery, a new study suggests.

"In our statin population, there was a significant decrease in events," said investigator Katharine Criner, MD, a fellow at New York University in New York City.

She presented the results here at the American Academy of Orthopaedic Surgeons (AAOS) 2014 Annual Meeting.

Patients suffer high rates of venous thromboembolic events after total joint replacement, Dr. Criner told Medscape Medical News. Without prophylaxis, up to 50% of patients who undergo total hip replacement and 84% of those who undergo total knee replacement suffer from blood clots.

Even with standard prophylaxis, the rate for blood clots ranges from 2% to 12%, she said.

Previous reports have suggested that statins might decrease the incidence of events in patients taking the drugs for high cholesterol. However, few, if any, researchers have looked at how statins affect patients undergoing joint replacement surgery.

Because statins not only reduce lipids, but also have pleiotropic anti-inflammatory effects, she wondered if they would have any effect on this population.

When Dr. Criner was a resident at the Temple University School of Medicine in Philadelphia, her team reviewed the outcomes of patients who had undergone total hip or knee replacement and who had a minimum of 11 months postoperative follow-up.

Patients were excluded from the analysis if they had undergone revision joint replacement surgery or total joint replacement after a fracture, had a history of blood clots, or were taking hormone replacement therapy.

The average patient was 65.5 years of age, and 61% of the cohort was obese; the mean body mass index was 33 kg/m².

All patients received standard postoperative therapy for venous thromboembolic events in accordance with AAOS guidelines. The use of an elastic stocking or other external compression device began at hospital admission, patient movement and rehabilitation started the first day after surgery and continued for several months, and anticoagulant therapy started the night before surgery and continued after discharge.

The study cohort consisted of 196 patients who were taking statins before the procedure and 221 who were not.

Sex, ethnicity, obesity rates, tobacco use, diabetes, cancer, history of venous thromboembolic events, diagnosis, laterality, and tourniquet time were similar in the 2 groups. The statin group had higher cholesterol levels and had significantly fewer events after the surgery.

Table. Thromboembolic Events

Event Statin Group, n (%) No Statin Group, n (%) P Value
Venous thromboembolic 15 (7.7) 32 (14.5) .027
Deep vein thrombosis 9 (4.6) 17 (7.7) .192
Pulmonary embolism or deep vein thrombosis 0 (0.0) 4 (1.8) .058

 

None of the patients died from a venous thromboembolic event, and there were no adverse reactions related to the statin therapy.

Despite the striking results, clinicians should wait for results from randomized controlled trials before using statins as prophylaxis in patients undergoing joint replacement, said Dr. Criner. Her team is planning to conduct such a study.

If the findings are supported, statins could prove especially useful for patients undergoing joint replacement when anticoagulant medications are contraindicated, such as in those who have suffered hemorrhagic stroke.

The high overall rate of symptomatic venous thromboembolic events in the study raises questions, said William Maloney, MD, chair of orthopedic surgery at Stanford University in Stanford, California.

"You have the rate you would expect to see without prophylaxis," he told Medscape Medical News.

Although the results are statistically significant, Dr. Maloney said he would need to see a larger patient population — as well as a prospective trial — to be convinced.

In response, Dr. Criner noted that the population in this study had a high rate of obesity, which could have raised the overall risk for venous thromboembolic events.

Dr. Criner and Dr. Maloney have disclosed no relevant financial relationships.

American Academy of Orthopaedic Surgeons (AAOS) 2014 Annual Meeting: Abstract P204. Presented March 11, 2014.

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