Radiological and blood markers predicting long term neurological outcome following decompressive craniectomy for malignant ischemic stroke: a preliminary single center study

Objective: Malignant ischemic stroke (MIS) is defined by progressive cerebral edema leading to intracranial pressure, compression of neural structurs and, eventually, death. Decompressive craniectomy (DC) has been advocated as a lifesaving procedure in the management of patients with MIS. This study aims to identify pre- and postoperative predictive variables of neurological outcomes in patients undergoing DC for MIS. Methods: We conducted a retrospective study of patients undergoing decompressive hemi-craniectomy in a single center from April 2016 to April 2020. Preoperative work-up included baseline clinical status, laboratory data, and brain CT. The primary outcome was the 6-months modified ranking score (mRS). The secondary outcome was the 30-day mortality. Results: During data capture a total of 58 patients fulfilled the criteria for MIS, of which 22 underwent DC for medically refractory increased ICP and were included in the present analysis. The overall median age was 58.5 years old. An immediate (24hr) postoperative GOSE score >= 5 was associated with good 6-month mRS (1-3)(p=0.004). Similarly, low postoperative neutrophils (p=0.002), low lymphocytes (p=0.004), decreased neutrophil to lymphocyte ratio (NLR)(p=0.02) and decreased platelet to lymphocytes ratio (PLR)(p=0.03) were associated with good neurological outcomes. Per-operative variables independently associated with worsened 6-month mRS were: increased age (OR 1.10, 95% CI 1.01-1.20, p=0.02), increased NIHSS score (OR 7.8, 95% CI 2.5-12.5, p=0.035), GCS < 8 at the time of neurosurgical referral (OR 21.63, 95% CI 1.42-328, p=0.02), and increased PTT time before surgery (OR 2.11, 95% CI 1.11-4, p=0.02). Decreased postoperative lymphocytes confirmed a protective role against worsened functional outcomes (OR 0.01, 95% CI 0.01-0.4, p=0.02). Decreased post-operative lymphocyte count was associated with showed a protective role against increased mRS (OR: 0.01, 95% CI: 0.01-0.4; p=0.02). The occurrence of hydrocephalus at postoperative CT scan was associated with 30-day mortality (p=0.005), while the persistence of postoperative compression of the ambient and crural cistern showed a trend towards significance (p=0.07). Conclusions This study reports that patients undergoing DC for MIS showing decreased postoperative blood inflammatory markers achieved better 6-month neurological outcomes than patients with increased inflammatory markers. Similarly, poor NIHSS, poor GCS, increased age, and larger PTT values at the time of surgery were independent predictors of poor outcomes. Moreover, the persistence of postoperative compression of basal cisterns and the occurrence of hydrocephalus is associated with 30-day mortality.