Manoeuvre Count in Thrombectomy – Don’t Stop ‘Til You Get Enough?
By Johannes Kaesmacher, MD, University Institute of Diagnostic and Interventional Neuroradiology, University Hospital Bern
For first- and second-generation devices it was very early shown that clinical outcome gets worse with each manoeuvre performed (i.e. device retrieval or contact aspiration attempt). Logically, manoeuvre count is associated with overall procedure time, time to reperfusion, and maybe most importantly, reperfusion quality. Hence, it often remains uncertain if manoeuvre count is independently associated with poor outcome or if it is mainly a surrogate of poor reperfusion quality and longer time from groin puncture to reperfusion.
Two recently published studies had a closer look at the association of manoeuvre count and poor outcome as well as their interdependence with reperfusion quality and time to reperfusion. In these articles, it was shown that manoeuvre count was independently associated with poor outcome, even when considering patients with the same reperfusion quality and after correction for time to reperfusion. Pathophysiological considerations explaining these effects include increased endothelial damage and aggravated blood-brain-barrier breakdown. Earlier small cohort studies have suggested several manoeuvre count cut-offs to indicate when to stop the intervention. However, before more data and well performed studies on that subject become available, stringent cut-offs to stop after a certain number of manoeuvres are unlikely to fit all patients. Still, some patients do benefit from achieving successful reperfusion even after the 6th manoeuvre. Nevertheless, the observation of increasing complications, increasing risk of symptomatic intracranial haemorrhage and decreasing likelihood of achieving good functional outcome with each additional manoeuvre performed should prompt a more careful evaluation of each additional manoeuvre attempted.
New algorithms providing probabilities of how much tissue of the penumbra has undergone infarction at any given time with a given reperfusion quality may inform decision making regarding this issue beyond the interventionalist’s gut feeling to pursue or stop the procedure.
Unlike manoeuvre count, the maxim for new data and analyses regarding this issue could be instead:
Keep on with the force don’t stop
Don’t stop ’til you get enough
1 When to Stop, Garcia-Tonel et al. https://www.ahajournals.org/doi/full/10.1161/STROKEAHA.119.025088
2 First-Pass Complete Reperfusion Improves Clinical Outcome in Thrombectomy Stroke Patients, Nikoubashman et al. https://www.ahajournals.org/doi/10.1161/STROKEAHA.119.025148