Nationwide survey of decompressive hemicraniectomy for malignant middle cerebral artery infarction in Japan

Abstract

Objective: Decompressive hemicraniectomy (DHC) for malignant middle cerebral artery (MCA) infarction has been shown to reduce mortality and improve functional outcomes in young adults; however, there is currently debate regarding how routinely such surgery should be performed in the clinical setting, considering the very high rate of disability and functional dependence among survivors. We herein report the current status of the frequency of and indications for DHC for malignant MCA infarction in Japan.

Methods: We retrospectively studied of cohort cases of DHC for malignant MCA infarction treated at pivotal teaching neurosurgical departments in Japan between January 2011 and December 2011. Information was obtained regarding patient characteristics, radiologic features, and outcomes during follow-up. The end points included 30-day mortality rate and functional outcomes, as measured according to the modified Rankin scale (mRS) score at 3 months.

Results: Three hundred fifty-five patients underwent DHC at 259 neurosurgical departments who replied to the survey, corresponding to a rate of 8.7% of the 4092 candidates with malignant MCA infarction, the latter being equivalent to 8.5% of patients with acute ischemic stroke identified during the same period. Among the patients undergoing DHC, the mean age was 67.0 years, and those ≥60 years of age comprised 80.2% of all DHC patients. The most frequently used modality for vascular imaging was magnetic resonance angiography (77.2%). DHC generally was performed between 24 and 48 hours after onset (38.9%), with 36.9% of patients undergoing surgery at ≥48 hours. At the time of surgery, 26.1% of the patients had a Glasgow Coma Scale score of ≤6. Presurgical midbrain compression was noted in 52.1% of the patients. The 30-day mortality after DHC was 18.6%, and factors affecting death were a Glasgow Coma Scale score of ≤6 (odds ratio [OR] 1.88, 95% confidence interval [95% CI] 1.05-3.32, P = 0.03) and midbrain compression (OR 2.28, 95% CI 1.31-4.09, P = 0.005). According to the multivariate analysis, only midbrain compression was an independent risk factor (OR 2.12, 95% CI 1.16-3.95, P = 0.01) for 30-day mortality. Modified Rankin scale scores at 3 months were available in 175 patients (49.3%), only 5.2% of whom exhibited a favorable functional outcome (mRS score ≤3). Meanwhile, 22.9% of the patients had an mRS score of 4, 26.9% had an mRS score of 5, and 45.1% were found to have died.

Conclusions: In the present study, less than one-tenth of candidates with malignant MCA infarction in Japan underwent decompressive surgery, and the vast majority of patients were elderly. Age was not found to be an independent factor for immediate mortality in this study, and performing surgery in the elderly may be justified based on additional evidence of functional improvements.

Keywords: Decompressive hemicraniectomy; Elderly patients; Functional outcomes; Malignant middle cerebral artery infarction; Mortality; Nationwide survey.