Risk of hemorrhage from unsecured, unruptured aneurysms during and after hypertensive hypervolemic therapy

Hypertensive hypervolemic therapy for vasospasm is widely practiced. It is not clear, however, whether the use of hypertension and hypervolemia as a treatment for vasospasm risks hemorrhage from an unsecured, unruptured aneurysm.

From 1991 to 2000, the neurovascular unit at the Massachusetts General Hospital treated 1908 aneurysms, of which 966 were ruptured. Forty patients with ruptured aneurysms had unsecured, unruptured aneurysms and underwent hypertensive hypervolemic therapy for vasospasm. Hypertension was induced by intravenously administered phenylephrine, norepinephrine, and/or dopamine, and hypervolemia was achieved by intravenously administered crystalloid and colloid solutions. The 24-hour mean arterial systolic blood pressure (SBP) and the 24-hour mean central venous pressure were calculated on the basis of hourly measurements during hypertensive hypervolemic treatment.

The 40 study patients harbored 124 aneurysms, of which 51 aneurysms were treated (clipping, 37; coiling, 14) by the time hypertensive hypervolemic therapy began, leaving 73 unsecured aneurysms at risk. The mean size of the unsecured aneurysms was 4.45 mm. Nineteen patients were treated with mild hypertension (SBP, 140-180 mmHg), 12 patients were treated with moderate hypertension (SBP, 180-200 mmHg), and 9 patients were treated with severe hypertension (SBP, >200 mmHg). The 24-hour mean SBP readings were 166.81 +/- 8.19, 187.57 +/- 5.79, and 204.01 +/- 3.75 mmHg for the mild, moderate, and severe hypertension groups, respectively. The mean central venous pressure was 10.43 +/- 3.89 mmHg. The mean course of hypertensive hypervolemic therapy was 7.25 days, and therapy began on mean post-subarachnoid hemorrhage Day 6.73. Twenty-eight aneurysms were eventually treated in later procedures (clipping, 25; coiling, 3). The mean interval to treatment was 6.93 months. In a treatment and follow-up period of 121.75 aneurysm-years of risk, there was no instance of hemorrhage.

Hypertension and hypervolemia do not seem to increase the risk of hemorrhage from unsecured, unruptured aneurysms in the acute setting or in their short-term natural history.