Background and Purpose —Intracerebral hemorrhage (ICH) is a highly morbid disease process. Perihematomal edema is reported to contribute to clinical deterioration and death. Recent experimental observations indicate that clotting of the intrahematomal blood is the essential prerequisite for hyperacute perihematomal edema formation rather than blood-brain barrier disruption. Methods —We compared a series of patients with spontaneous ICH (SICH) to a series of patients with thrombolysis-related ICH (TICH). All patients were imaged within 3 hours of clinical onset. We reviewed relevant neuroimaging features, emphasizing and quantifying perihematomal edema. We then analyzed clinical and radiological differences between the 2 ICH types and determined whether these factors were associated with perihematomal edema. Results —TICHs contained visible perihematomal edema less than half as often as SICHs (31% versus 69%, P <0.001) and had both lower absolute edema volumes (0 cc [25th, 75th percentiles: 0, 6] versus 6 cc [0, 13], P <0.0001) and relative edema volumes (0.16 [0.10, 0.33] versus 0.55 [0.40, 0.83], P <0.0001). Compared with SICHs, TICHs were 3 times larger in volume (median [25th, 75th percentiles] volume 69 cc [30, 106] versus 21 cc [8, 45], P <0.0001), 4 times more frequently lobar in location (62% versus 15%, P <0.001), 80 times more frequently contained blood-fluid level(s) (86% versus 1%, P <0.001), and were more frequently multifocal (22% versus 0%, P <0.001). Conclusions —The striking qualitative and quantitative lack of perihematomal edema observed in the thrombolysis-related ICHs compared with the SICHs provides the first substantial, although indirect, human evidence that intrahematomal blood clotting is a plausible pathogenetic factor in hyperacute perihematomal edema formation.
Natural History of Perihematomal Edema in Patients With Hyperacute Spontaneous Intracerebral Hemorrhage
Background and Purpose— The natural history of perihematomal edema in human hyperacute spontaneous intracerebral hemorrhage (ICH) has not been well described. Methods— This study was a secondary analysis of a previously reported prospective, population-based study of hematoma growth in 142 patients with spontaneous ICH. Patients were first imaged within 3 hours of onset, then 1 and 20 hours later. We excluded patients with anticoagulant use (n=7), underlying aneurysm/vascular malformation (n=9), trauma (n=1), incomplete data (n=20), infratentorial ICH (n=17), and no consent (n=2), leaving an overall study population of 86 patients. From this overall group we further excluded patients with intraventricular extension (n=38), subsequent surgery (n=5), or death (n=2) before 20-hour postbaseline CT. This second, “restricted” analysis group of 41 patients was relatively devoid of clinical or radiological variables likely to confound edema measurement. Absolute and relative edema volumes (edema volume divided by hematoma volume) were descriptively summarized. Correlations between baseline edema volumes and relevant clinical and radiological variables were then performed. Results— Overall, median absolute edema volume increased from 6.93 to 14.4 cm 3 during the first 24 hours after ICH, and median relative edema volume increased from 0.47 to 0.81. In the restricted group, median absolute edema volume was 7.4 cm 3 at baseline and 11.0 cm 3 at 24 hours after ICH, and median relative edema volume increased from 0.55 to 0.81. Baseline relative edema volume was significantly negatively correlated with subsequent change in relative edema volume from baseline to 20-hour CT ( r =0.57, P =0.0002) but was not significantly correlated with other clinical and radiological variables, including hematoma volume or change in hematoma volume. Conclusions— Perihematomal edema volume increases by approximately 75% during the first 24 hours after hyperacute spontaneous ICH. Patients with the least amounts of baseline relative edema volume were most likely to develop significant additional amounts of edema during the first 24 hours after spontaneous ICH.
Relative Edema Volume Is a Predictor of Outcome in Patients With Hyperacute Spontaneous Intracerebral Hemorrhage
Background and Purpose— Little is known about the relationship between perihematomal edema in spontaneous intracerebral hemorrhage (ICH) and outcome. The purpose of this study was to determine whether absolute or relative edema volume (edema volume divided by hematoma volume) predicts mortality or functional outcome in patients with hyperacute spontaneous ICH. We hypothesized that increasing baseline relative edema volume is associated with greater probability of poor functional outcome. Methods— This was a secondary analysis of a prospective, population-based study of hematoma growth in 142 patients with spontaneous ICH. Patients were imaged within 3 hours of onset, then 1 and 20 hours later. Our primary analysis excluded patients with anticoagulant use (n=7), underlying aneurysm/vascular malformation (n=9), trauma (n=1), incomplete data (n=20), infratentorial ICH (n=17), intraventricular extension (n=38), and no consent (n=2). We analyzed whether associations existed between baseline edema volumes or other clinical/radiological variables and either 12-week modified Rankin Scale score >2 or 30-day mortality. Secondary analyses used 20-hour CT scan data, all patients with supratentorial ICH, and 12-week Barthel Index score <85. Results— By multivariable logistic regression analysis, baseline relative edema was the strongest independent predictor of functional outcome and was associated with lesser odds of poor 3-month functional outcome (odds ratio, 0.09 per 1.0-unit [100%] increase; 95% CI, 0.01 to 0.64; P =0.016) and 12-week Barthel Index score <85 (odds ratio, 0.12; 95% CI, 0.02 to 0.91; P =0.039) but did not predict mortality. Secondary analyses confirmed this result. Absolute edema volume predicted neither mortality nor functional outcome. Conclusions— Relative edema is strongly predictive of functional outcome in patients with hyperacute supratentorial spontaneous ICH without intraventricular extension.