Low-dose aspirin led to low risk of VTE after shoulder arthroplasty
Use of low-dose aspirin yielded a low risk of venous thromboembolism and medication-associated complications after primary shoulder arthroplasty, according to results presented at the American Shoulder and Elbow Surgeons Annual Meeting.
“Given the significant potential morbidity associated with postoperative [venous thromboembolism] VTE coupled with the favorable results observed in this study, strong consideration should be given to routine prophylaxis with low-dose aspirin unless the patient has risk factors which may warrant alternative treatment,” Surena Namdari, MD, MSc, said in his presentation.
Study approach
Namdari and colleagues prospectively recorded adverse events and contacted all patients who underwent primary shoulder arthroplasty 90 days after surgery to assess whether they went to the emergency room for any reason, had to be readmitted to a hospital or had any other complications.
“Lastly, a review of our [electronic medical record] EMR was also performed to identify complications,” Namdari said in his presentation. “During this period, all patients undergoing shoulder arthroplasty received intermittent pneumatic compression devices intraoperatively and received some form of medication for postoperative VTE prophylaxis.”
Namdari added all patients underwent preoperative risk stratification based on several factors pertaining to their overall medical risk, including baseline demographic information, medical comorbidities, history of VTE, the type of arthroplasty performed and preoperative medication history. Researchers assessed the overall rate and risk factors for symptomatic VTE postoperatively.
“We also looked at what was used for VTE prophylaxis and if there were any bleeding-related complications associated with either prophylactic or therapeutic treatment,” Namdari said.
Risk of VTE
Namdari noted patients had an overall rate of VTE of 0.63%, with nine deep vein thrombosis and six pulmonary embolisms. Patients medically stratified as high risk had a significantly higher risk of VTE vs. patients stratified as medically low risk, according to Namdari. He also noted patients with a history of prior deep vein thrombosis, asthma and cardiac arrythmia had an association with having a VTE event.
“In this study, low-dose aspirin was used for VTE prophylaxis in 2,141 patients, which represents approximately 90% of the total patient population,” Namdari said. “The overall VTE rate in those patients treated with aspirin was 0.56% compared to 1.2% of patients [who] received other medications postoperatively.”
Although underpowered, patients who were medically high risk or who had a history of prior deep vein thrombosis had a similar VTE rate when prophylaxis included low-dose aspirin vs. other medications, according to Namdari.
“Of all the patients who received low-dose aspirin as VTE prophylaxis, we found that only four or 0.19% had a hematoma that required aspiration in the office,” Namdari said.
Perspective
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Symptomatic VTE after shoulder arthroplasty has been seen to have a rate of 0.41% to 0.53% in various publications, so its incidence is relatively rare. Nonetheless, the more significant complications that can occur are catastrophic (pulmonary embolism among the most significant), so most shoulder arthroplasty surgeons have chosen to give prophylaxis to their patients against the threat of symptomatic VTE. In this backdrop, Surena Namdari, MD, MSc, and his colleagues at the respected shoulder unit of the Rothman Orthopaedic Institute performed this retrospective study to assess the relative effect of low-dose aspirin in VTE prevention. They found that aspirin had a comparable overall VTE rate of 0.56% to much of the literature and a VTE rate that was better than in patients who received other VTE prevention medications.
This study, like many that investigate VTE, did not obtain scheduled ultrasonic evaluation of the upper and lower extremities. As it is known that asymptomatic deep vein thrombosis (DVT) occurs on a measurable basis, the estimation of pharmacotherapies in studies like these to “prevent” all DVT is typically underrepresented. As asymptomatic DVT is generally benign and the cost to perform ultrasound on all patients is prohibitive, this is a minor and an accepted limitation.
The emergence of more costly pharmacotherapies to prevent VTE comes with pressure to utilize them. Namdari and his colleagues provide ample proof that the dramatically inexpensive alternative aspirin is more than a viable one and indirectly provide proof of its value in a health care environment that is looking to lessen its cost curve and should be commended for that.
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Kirsch JM, et al. Low-dose aspirin and the rate of symptomatic venous thromboembolic complications following primary shoulder arthroplasty. Presented at: American Shoulder and Elbow Surgeons Annual Meeting; Oct. 2-3, 2020 (virtual meeting).
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