The prognostic significance of visible infarction on computed tomography following lacunar stroke: results of a long-term follow-up study.

BACKGROUND AND PURPOSE

Substantial variability in functional outcome and relatively few factors predictive of death or degree of recovery have been observed in patients with lacunar stroke. Such indicators are of great use in the selection of optimal rehabilitation strategies after stroke. Although computed tomography (CT) of patients with a clinical diagnosis of lacunar stroke performed within the first 10 days shows evidence of cerebral infarction in 50% to 60%, the prognostic significance of a visible ischemic lesion on CT is unclear.

METHODS

633 patients who presented with symptoms consistent with lacunar stroke between June 1990 and February 1998 were studied. One hundred fourteen patients imaged with magnetic resonance, 41 patients with nonischemic diagnoses (hemorrhage or tumor), 57 patients imaged within 12 hours of ictus, and 17 patients with incomplete follow-up were excluded from the analysis. The remaining 404 patients were divided into 2 groups, depending on the appearance of the CT scan. Patients with a low-attenuation area on the CT scan consistent with an ischemic lesion in an appropriate region of the brain to explain the presenting symptoms were classified as "CT positive." Patients with either a normal CT scan of the brain or a scan that showed a lesion in an area inconsistent with the presenting symptoms were classified as "CT negative." A series of known or suspected prognostic factors were recorded for each patient: blood pressure, age, smoking, plasma glucose level, serum cholesterol level, and serum triglyceride level. Delay from stroke onset to scanning was also noted. The authors considered 3 outcome measures: survival time, outcome at 6 months after the stroke, and total length of hospital stay for the stroke admission. Six-month outcome was categorized as good (alive at home) or poor (alive in care or dead).

RESULTS

There was no difference in survival between the 2 groups (P= .29, log-rank test). After adjusting for other significant prognostic factors (age; relative hazard per additional decade 1.67, P< .0001: plasma glucose level; relative hazard per additional mmol/l 1.08, P= .03) in a proportional hazards model, presence of visible infarction remained nonsignificant (relative hazard 0.84, P= .40). After adjustment for the other significant factor (age, P= .0001), there was no significant difference in 6-month outcome between CT positive and CT negative patients (P= .61). Median total length of hospital stay was not significantly different between the 2 groups (CT positive, 9 days; CT negative, 8 days; Mann-Whitney test, P= .29).

CONCLUSION

The authors conclude that in their cohort of patients, having corrected for other prognostic variables, the presence of visible infarction on CT brain scan performed between 12 hours and 30 days of onset of lacunar symptoms is not predictive of duration of hospital stay or of longer term outcome.