Objective: To assess the time course of secondary ischemia and first rebleeding and the relation between the timing of operation and the time course of secondary ischemia in a consecutive series of patients with aneurysmal subarachnoid hemorrhage (SAH).
Methods: Life table methods were used to assess the daily rates of ischemia and of rebleeding on day 0, day 1 to 3, day 4 to 10, day 11 to 14, and day 15 to 21. The authors compared the time course of secondary ischemia between patients operated within 4 days of SAH and those operated after 10 days.
Results: Of 346 patients included, 220 were operated, 131 within 4 days and 74 after 10 days. The rebleed rate was highest on the day of the initial hemorrhage, then diminished, and increased slightly again during the second week. The rate of secondary ischemia was highest on day 4, diminished after day 10, but peaked again from day 14 to 18 for patients who were operated later than 10 days after aneurysmal rupture. The peak rate of ischemia was much higher after early than after late operation. Although patients with early operation were in a better clinical condition on admission, with a relatively low risk of secondary ischemia, the overall rate of secondary ischemia was as high as in patients with delayed operation. From day 11 to 21 the rebleed rate was higher than the rate of secondary ischemia.
Conclusions: These results indicate that operation is a risk factor for ischemia, especially when performed early. If operation is postponed, it should be planned soon after day 10, because of the relatively high rebleed rate from day 11 to 21.