Transcranial Doppler directed dextran therapy in the prevention of carotid thrombosis: three hour monitoring is as effective as six hours.

Background: Six hours' monitoring by transcranial Doppler (TCD) has been successful in directing Dextran therapy in patients at high risk of thrombotic stroke after carotid endarterectomy (CEA).

Objective: Is 3 h of routine monitoring as effective as 6 h in the prevention of early postoperative thrombotic stroke?

Methods: Prospective, consecutive study in all patients with an accessible cranial window. Methods: One hundred and sixty-six patients undergoing CEA underwent 3 h of postoperative monitoring by TCD. Any patient with > 25 emboli detected in any 10 min period or those with emboli that distorted the arterial waveform were commenced on an incremental infusion of dextran 40.

Results: The majority of patients destined to embolise will do so within the first 2 postoperative hours. Dextran therapy was instituted in nine patients (5%) and rapidly controlled this phase of embolisation although the dose had to be increased in three (33%). No patient suffered a postoperative carotid thrombosis but one suffered a minor stroke on day 5 and was found to have profuse embolisation on TCD; high dose dextran therapy was again instituted, the embolus count rate fell rapidly and he made a good recovery thereafter. Overall, the death and disabling stroke rate was 1.2% and the death/any stroke rate was 2.4%.

Conclusions: Three hours of postoperative TCD monitoring is as effective as 6 h in the prevention of postoperative carotid thrombosis.