Abstract 1122‐000222: Repeated Mechanical Thrombectomy for Recurrent Large Vessel Occlusion: A Meta‐Analysis of Individual Participant Data

Introduction : Mechanical thrombectomy (MT) has become the standard treatment of acute ischemic stroke (AIS) caused by large vessel occlusion (LVO), with different techniques used to achieve revascularization of the occluded vessel. However, early re‐occlusion of the target vessels could still take place in a considerable proportion of patients who already underwent MT for LVO. Therefore, we conducted this systematic review and individual participant data (IPD) meta‐analysis to provide more comprehensive evidence regarding the efficacy of repeat thrombectomy for recurrent LVO in early after successful first‐time MT. Methods : A computerized search on MEDLINE via PubMed, SCOPUS, Web of Science, EMBASE, and Cochrane library using the relevant keywords was performed. The retrieved references were screened, and the relevant data were extracted. STATA and SPSS were used to perform this IPD meta‐analysis. Results : Twenty studies were included, of which ten studies were observational studies (n = 21,251 patients) and 10 cases reports (n = 10 patients). Out of the included patients, 266 patients (62.78% females) were identified with recurrent LVO. The overall prevalence of recurrent LVO was 1.6%, 95% CI (1.0% to 2.8%), p<0.001. The mean age of the included patients was 65.67±16.23 years. Cardiac embolism was the most common cause of stroke in both times (52%). The median number of days between the first and second LVO was 15 days (IQR: 4–191). Regarding the National Institute of Health Stroke Scale (NIHSS), the first and second MT reduced it significantly (MD = ‐8.91, 95% CI: ‐10.02 to ‐7.82) and (MD = ‐5.97, 95% CI: ‐7.53 to ‐4.43), respectively, with a significant difference between both procedures (p = 0.001). The mean ASPECT after the first MT was 8.65±1.45, and after the second MT was 8.01±1.88. A significant weak correlation was observed between the ASPECT of first MT and NIHSS before it (r = ‐0.270, p = 0.001). Based on the thrombolysis in cerebral infarction (TICI) grading system, the first MT resulted in 57.3% complete perfusion, 42.1% partially filling, and 0.7% no/minimal filling, while the second MT resulted in 48% complete perfusion, 30% partially filling, and 6.67% no/minimal filling, with a significant difference between both MTs (p = 0.042). Regarding the modified Rankin scale (mRS) at 90 days after the first MT, “0” was the most frequent outcome (26.9%), followed by “2” (13.0%), “1” (12.4%), and “4” (7.3%). On the other hand, the 90‐day mRS after the second MT was categorized as the following: “6” in 13.5%, “3” in 13.5%, “2” in 11.9%, “1” in 11.9%, and “4” in 9.3%. Conclusions : In properly selected patients with recurrent LVO, repeated MT appears to be feasible and safe. A prior MT procedure should not discourage aggressive treatment as these patients may achieve similar rates of good clinical outcomes as those who undergo single MT.

Filling of closed surfaces

Let [Formula: see text] denote a closed oriented surface of genus [Formula: see text]. A set of simple closed curves is called a filling of [Formula: see text] if its complement is a disjoint union of discs. The mapping class group [Formula: see text] of genus [Formula: see text] acts on the set of fillings of [Formula: see text]. The union of the curves in a filling forms a graph on the surface which is a so-called decorated fat graph. It is a fact that two fillings of [Formula: see text] are in the same [Formula: see text]-orbit if and only if the corresponding fat graphs are isomorphic. We prove that any filling of [Formula: see text] whose complement is a single disc (i.e. a so-called minimal filling) has either three or four closed curves and in each of these two cases, there is a unique such filling up to the action of [Formula: see text]. We provide a constructive proof to show that the minimum number of discs in the complement of a filling pair of [Formula: see text] is two. Finally, given positive integers [Formula: see text] and [Formula: see text] with [Formula: see text], we construct a filling pair of [Formula: see text] such that the complement is a union of [Formula: see text] topological discs.

Prescribing the behavior of Weil–Petersson geodesics in the moduli space of Riemann surfaces

We study Weil–Petersson (WP) geodesics with narrow end invariant and develop techniques to control length-functions and twist parameters along them and prescribe their itinerary in the moduli space of Riemann surfaces. This class of geodesics is rich enough to provide for examples of closed WP geodesics in the thin part of the moduli space, as well as divergent WP geodesic rays with minimal filling ending lamination. Some ingredients of independent interest are the following: A strength version of Wolpert's Geodesic Limit Theorem proved in Sec. 4. The stability of hierarchy resolution paths between narrow pairs of partial markings or laminations in the pants graph proved in Sec. 5. A kind of symbolic coding for laminations in terms of subsurface coefficients presented in Sec. 7.