1474. Analysis Of The Renin-Angiotensin System (RAS) Inhibitors In ACDF Patients: Might RAS Influence Spinal Fusion?

Authors: Alexander Perdomo-Pantoja, MD; Feras Shamoun, BS; Christina Holmes, PhD; Wataru Ishida, MD; Seba Ramhmdani, MD; Ali Bydon, MD; Nicholas Theodore; Sheng-fu Larry Lo, MD; Timothy F. Witham, MD (Baltimore, MD)

Recently, studies suggest an association between Renin-angiotensin system (RAS) inhibitors and bone healing, particularly in the context of bone fractures. We explored whether there is a correlation between the use of antihypertensive medication and outcomes in anterior cervical discectomy and fusion (ACDF) surgery.
A retrospective chart review was performed, including 128 degenerative disc disease patients who underwent ADCF, with 1-year minimum follow-up. Demographic data, comorbidities, antihypertensive medication, neurological examination, and fusion status were collected. Spinal fusion was assessed via plain cervical x-ray, resorting to dynamic radiographs in cases of uncertainty.
Of the 128 patients (52% females, 48% males, median age of 53.7 years), 46 hypertensive patients were identified: 44 (95.7%) were taking antihypertensive medication as follows: 17 angiotensin-II receptor blockers [ARBs], 14 angiotensin-converting enzyme inhibitors [ACEIs], and the remaining 13 other drugs). In the analysis of fusion rates, patients treated with ARBs exhibited a higher fusion rate compared to those untreated or treated with ACEIs (p=.03 and .005, respectively). Patients treated with ARBs displayed a relative benefit of fusion over untreated patients of 1.289 (95%CI 1.12,1.48, p=.03). Smoking exhibited a negative correlation with spinal fusion compared to non-smokers (p=.03). In the neurological examination, ACEIs were correlated with worse preoperative modified Japanese Orthopedic Association (mJOA) and Nurick scores compared to non-treatment (p=.01 and <.001). Patient age, diabetic status, hypertension, and other drugs, did not significantly affect fusion rates or neurologic examination scores.
In ACDF patients, we observed that ARBs were associated with higher fusion rates. Conversely, smoking was related to failed fusion. Also, ACDF patients treated with ACEIs showed worse preoperative mJOA and Nurick scores compared to untreated patients. Further studies with a larger population and different spinal levels are needed to verify that ARBs have beneficial effects on spinal fusion.