Geniculate artery embolization (GAE) is responsible for statistically significant improvements in pain scores from baseline out to three months, the preliminary results of the first European prospective study on the procedure show. Mark Little (University of Reading and Royal Berkshire NHS Foundation Trust, Reading, UK) presented these early results of the GENESIS study (Geniculate artEry embolisatioN in patiEnts with oSteoarthritis of the knee) today at the Annual Scientific Meeting of the Cardiovascular and Interventional Radiological Society of Europe (CIRSE; 7–11 September, Barcelona, Spain).
While cautious about overinterpreting what he stresses are early data, Little is nonetheless optimistic about these positive results, telling delegates at CIRSE: “Musculoskeletal (MSK) embolisation is the next frontier in embolotherapy”.
The GENESIS investigators report “excellent recruitment”, with 34 patients enrolled since the trial started recruiting. Little believes this reflects the fact that GAE is serving an unmet clinical need. Osteoarthritis is a common condition with a growing prevalence due to an increasingly obese and elderly European population. For those patients older than 45 years of age who have mild to moderate osteoarthritis that is resistant to conservative treatment, yet is not severe enough to warrant joint replacement, GAE is being hailed as a potential solution.
Detailing the scientific rationale for GAE, Little explained to the CIRSE audience that inflammation of the knee joint drives synovial angiogenesis through macrophage activation. “It is hypothesised that angiogenesis contributes to structural damage and pain in osteoarthritis”, he explained, “and GAE can be used to treat this pain”.
The single centre, prospective GENESIS study (funded by Merit Medical and the National Institute for Health Research, NIHR) uses changes in pain measurements from baseline to post-procedural follow-up to assess the efficacy of GAE. Consultant interventional radiologists performed the procedure using 100–300micron Embosphere particles (Merit Medical) diluted in 20ml contrast.
Pain is a complex multifactorial process and the GENESIS study protocol is using a number of novel tools to assess patient’s pain. Little’s research group at University of Reading, UK, is using neuropsychological assessments employing functional magnetic resonance imaging (fMRI) of the brain to map pain, in addition to measuring Visual Analog Scores (VAS) pain scores, and using the Knee Injury Osteoarthritis Outcome Score (KOOS), a validated questionnaire used throughout the orthopaedic literature on knee osteoarthritis.
Overall Visual Analogue Scale (VAS) decreased from baseline at both six weeks and three months follow-up: mean VAS was almost 70 pre-GAE, and just below 30 six weeks post-procedure. VAS score was 33 at three months (p<0.005). Meanwhile, Knee Injury and Osteoarthritis Outcome Score (KOOS) increased from baseline to one-year follow-up, representing a reduction in pain and symptoms. Mean KOOS was 39 at baseline, 62 (p<0.005) and 85 one-year post-procedure.
There were two minor complications, observed in the 22 patients treated with GAE for this interim analysis—two cases of transient skin discoloration early on.
Explaining the significance of these results, Little tells Interventional News, “I really want to stress how important it is to precisely measure patient’s pain. We need to up our game in terms of accurate outcome measures in MSK embolization. We are very fortunate to have the Center for Integrative Neuroscience and Neurodynamics (CINN) at the University of Reading to carry out the pain assessments as part of the GENESIS study.”
Little reported that preliminary neuropsychology data reveal signals that may predict treatment failure. “We are continuing to model the neuropsychological pain experiments with the ultimate aim of aiding patient selection”, he said. The triallists are instituting neuromodulation prior to the procedure to improve clinical outcomes.