Baseline Headache Phenotype and Early Headache Response After Venous Sinus Stenting for Symptomatic Transverse Sinus Stenosis

Objectives: Headache response after venous sinus stenting (VSS) is variable, and it is unclear whether the presenting headache phenotype is associated with early improvement. We examined the association between clinically recorded baseline headache phenotype and headache status at first follow-up after VSS for symptomatic transverse sinus stenosis. Materials and Methods: This secondary analysis used a single-center registry comprising 75 VSS procedures. Patients with baseline headache, a recorded headache phenotype, and complete first-follow-up headache status were included. Phenotype was a clinician-assigned registry category ("IIH-like," "migraine," or "tension type"); it was not independently adjudicated against ICHD-3, and the "IIH-like" label did not require a recorded IIH diagnosis. The primary outcome was headache improvement at first follow-up. Phenotype groups were compared with Fisher’s exact test; exact binomial confidence intervals and mean bias-reduced logistic regression were used because there were few non-improvement events. Results: Forty-six patients had baseline headache (median age 32 years; 93.5% female; median BMI 29.1 kg/m²); only 12/46 (26.1%) had a recorded IIH diagnosis. Recorded phenotypes were IIH-like in 23, migraine in 13, and tension type in 10 patients. Median first follow-up was 64.5 days. Overall, 33/46 patients improved (71.7%; exact 95% CI 56.5%-84.0%). Improvement occurred in 18/23 patients with IIH-like headache (78.3%), 11/13 with migraine (84.6%), and 4/10 with tension-type headache (40.0%; overall Fisher exact P = 0.046). In mean bias-reduced regression adjusted for recorded IIH diagnosis, the association was attenuated: adjusted odds ratios were 4.63 (95% CI 0.94-22.79) for IIH-like and 6.37 (0.97-42.06) for migraine relative to tension type (global phenotype P = 0.093). Additional adjustment for variable follow-up duration gave similar results (global P = 0.103). Conclusions: Early headache improvement was common after VSS, but the tension-type group had a lower observed response proportion. Because the phenotype categories were non-adjudicated descriptive registry labels, and because the association attenuated after limited adjustment with imprecise estimates, phenotype should be considered hypothesis-generating rather than a validated treatment-selection marker. Prospective studies using adjudicated headache diagnoses and repeated validated headache outcomes are needed.