Hemodilution in Acute Stroke

Abstract

Intentional hemodilution has been shown to increase cerebral blood flow under normal conditions and in experimental stroke. Clinical trials of hemodilution in patients with acute stroke have employed dextran, hydroxyethyl starch or albumin as hemodiluting agents, often in combination with venesection. An overview of 12 randomized clinical trials of hemodilution in acute stroke (total 2,509 patients) shows no overall effect on survival (odds ratio 1.01 for active treatment:control). In surviving patients, neurological outcome is similar in hemodilution and control groups. The proportion of patients that are independent at follow-up does not differ between the groups (odds ratio 0.98). It has not been possible to identify any subgroup in which the therapy is clearly beneficial. Recent pilot clinical studies indicate that the effects of more aggressive hemodilution schemes could be worthwhile to explore. Until the results of new controlled trials are available, it seems that hemodilution has no place in the routine management of patients with ischemic stroke.

Organisation of Stroke Services: The Role of Stroke Units

“…The gains o f stroke unit rehabilitation were not present at the end of one year [60], A significant decrease in m ortality (31 vs. 41%), a higher discharge rate (63 vs. 52%) and a greater independence at discharge (47 vs. 38%) were also seen in patients managed on a stroke unit compared with general wards in a longitudinal study [61]. Similar findings o f lower mortality, greater functional independence, lesser institutionalisation and decreased length of hospital stay (15% still in hospital after 4 months compared with 39% on general wards) associated with stroke unit management were reported in another study (table 1) [62,63]. The impact of these studies was limited because only a small proportion of eligible stroke patients were included and the outcome of acute rehabilitation was assessed at an inconsistent time [58,61,62].…”

“…The impact of these studies was limited because only a small proportion of eligible stroke patients were included and the outcome of acute rehabilitation was assessed at an inconsistent time [58,61,62]. There were significant differences in the am ount of therapy input [61], its tim ing [64] and the proportion of patients receiving this input between intervention and control groups [61,64], Poor random isation techniques and the inclusion o f stroke unit patients in a haemodilution trial compromised the findings o f one study [62,63]. The more recent studies [65,66] are better designed and have used a consistent approach to the diagnosis and treatm ent of disability.…”

Cerebral Hematocrit Decreases With Hemodynamic Compromise in Carotid Artery Occlusion

“…1 Therefore, in patients with ischemic cerebrovascular disease, the in vivo measurement of regional cerebral Hct is useful in estimating how the viscosity contributes to the development of cerebral ischemia: High Hct in low-flow areas implies that ischemia may be adversely affected by elevated blood viscosity, and the lowering of Hct may be important in improving the ischemic state. In the therapeutic manipulation of blood rheology in stroke, the clinical effects of which are very controversial, 5 it seems essential to investigate the change in regional cerebral Hct. However, few data on regional cerebral Hct in patients with ischemic cerebrovascular disease are reported in the literature.…”

Thrombolysis in acute ischemic stroke: does it work?

“…7 Using the second approach, hemodilution is ineffective in the generality of ischemic stroke patients. 8 Antithrombotic therapy (with heparin, warfarin, or aspirin) has not been properly tested in large randomized clinical trials. Although variably used in acute stroke, 9 we do not know if these drugs improve outcome.…”