Recurrence rate of chronic cerebral arterial occlusion with mean transit time more than 6 s: a case series

Chronic cerebral arterial occlusion and stenosis are significant medical conditions which can cause hemodynamic impairment, leading to symptoms such as transient ischemic attacks and progressive or recurrent strokes. Surgical bypass is a treatment modality available for these conditions, but its results are only similar to those of the best medical treatment. The CMOSS study analyzed a subgroup of patients receiving the best medical treatment and found that individuals with prolonged mean transit time may benefit from the surgical bypass procedure. The objective of this report was to investigate the recurrence rate of unilateral chronic cerebral arterial occlusion with a mean transit time of more than 6 s treated with STA-MCA by-pass procedure during the follow-up period. A retrospective review was conducted between January 2010 and December 2024 at Rajavithi Hospital, including patients who received the best medical treatment, had a mean transit time (MTT) greater than 6 s, and also had a relative cerebral blood flow (rCBF) of ≤0.5 m. All patients underwent STA-MCA bypass surgery. Data collected included demographic information, recurrence rates, pre- and post-operative Glasgow Coma Scores, and modified Rankin Scores. The demographic data of the predominantly male patients showed a mean age of 57.2 years. Regarding CT perfusion, all patients had an MTT greater than 6 s, and 93.3 % had an rCBF below 0.5. The postoperative results indicated that the modified Rankin Scale (MRS) was similar to the preoperative condition, but also that 80 % of symptoms improved. The recurrence rate was 0 % during the follow-up period; however, 3 patients died, and the cause of death in all cases was pneumonia (not due to ipsilateral stroke). This report demonstrates that STA-MCA bypass is potentially useful for patients with single-vessel chronic ICA/MCA stenosis or occlusion who do not respond to the best medical treatment, as indicated by CT perfusion showing an MTT >6 s and an rCBF ≤0.5.