Perioperative management of DMARDs
Recent joint guidelines from the American College of Rheumatology and American Association of Hip and Knee Surgeons specifically address this issue in patients undergoing elective joint replacement (Arthritis Rheumatol. 2017 Aug;69[8]:1538-51).
“The quality of evidence isn’t high, but at least it’s a starting point,” Dr. Wallace said.
Patients with rheumatoid arthritis, systemic lupus erythematosus, spondyloarthropathies, and other rheumatic diseases who are on methotrexate or other nonbiologic DMARDs should be maintained on their current dose, according to the guidelines.
In contrast, all biologic agents should be withheld prior to surgery, which should be scheduled to coincide with the end of the dosing cycle for that specific biologic. The biologic agent should be resumed only once adequate wound healing has occurred, typically about 14 days post-THA/TKA.
Patients on daily glucocorticoids should continue on their current dose; supraphysiologic stress dosing is to be avoided.
Low-dose aspirin for VTE prophylaxis
“It seems like nothing has been such an enduring controversy in the comanagement literature as the question of whether aspirin is an effective prophylactic agent for prevention of DVT post THA/TKA,” according to Dr. Wallace.
She noted that in the space of just 4 years between the eighth and ninth editions of the American College of Chest Physician guidelines, that organization underwent a 180-degree reversal on the issue – whipsawing from a grade 1A recommendation against aspirin in 2008 to a 1B recommendation for it in 2012.
The literature is increasingly supportive of the use of aspirin for venous thromboembolism (VTE) prophylaxis in low-risk THA/TKA patients. Separate guidelines from the American Academy of Orthopaedic Surgeons (AAOS) and the Surgical Care Improvement Project, as well as the chest physicians, support the practice.
The hitch is that there is as yet no single validated risk-stratification protocol. AAOS recommends 325 mg of aspirin twice daily for 6 weeks. But a prospective crossover study of more than 4,600 total joint arthroplasty patients conducted by investigators at Thomas Jefferson University in Philadelphia showed that 81 mg BID for 4 weeks was just as effective as was 325 mg b.i.d., albeit with an incidence of GI bleeding that to their surprise wasn’t significantly lower (J Bone Joint Surg Am. 2017 Jan 18;99[2]:91-8).
Dr. Wallace anticipates definitive answers on VTE prophylaxis to come from the ongoing Patient-Centered Outcomes Research Institute-supported PEPPER (Comparative Effectiveness of Pulmonary Embolism Prevention After Hip and Knee Replacement) trial. In that study, roughly 25,000 patients undergoing THA/TKA are being randomized to prophylactic aspirin at 81 mg b.i.d., warfarin at an International Normalized Ratio of 2.0, or rivaroxaban (Xarelto). Endpoints include mortality, VTE, and bleeding. Results are expected in 2021.
Preoperative prediction of postop delirium
Unrecognized preoperative cognitive impairment in older patients without dementia who are undergoing THA/TKA is a common and powerful risk factor for postop delirium and other complications, as demonstrated recently by investigators at Harvard University and affiliated hospitals.
They had 211 patients aged 65 or older, none with known dementia, take the Mini-Cog screening test prior to their surgery. Fully 24% had probable cognitive impairment as reflected in a score of 2 or less out of a possible 5 points on this simple test, which consists of a three-word recall and clock drawing.
“I was very surprised at this high rate. These are patients who are at risk for delirium in the hospital when you’re taking care of them,” Dr. Wallace observed.
In the Harvard study, the incidence of postop delirium was 21% in patients with a Mini-Cog score of 2 or less, compared with 7% who scored 3-5, for an odds ratio of 4.5 in an age-adjusted multivariate analysis. Moreover, 67% of the low scorers were discharged somewhere other than home, in contrast to 34% of patients with a preop Mini-Cog score of 3-5, for an adjusted 3.9-fold increased risk. The group with a Mini-Cog score of 2 or less also had a significantly longer hospital length of stay (Anesthesiology. 2017 Nov;127[5]:765-74).
Perioperative gabapentin is often added to the medication regimen of older surgical patients to reduce postop delirium. The latest evidence indicates that doesn’t work, as demonstrated in a recent 697-patient randomized trial. The incidence of delirium during the first 3 days post surgery as measured by the Confusion Assessment Method was 22.4% in patients randomized to 900 mg of gabapentin per day, and 20.8% with placebo. Nearly 200 participants had THA or TKA, and in that subgroup, there was an even stronger – albeit still not statistically significant – trend for a higher delirium rate with gabapentin than with placebo (Anesthesiology. 2017 Oct.127[4]:633-44).
“Think twice about adding gabapentin to the pain regimen for THA/TKA/spine patients for the purpose of preventing postop delirium,” she advised.