Penumbra around chronic cerebral infarction?

Area of Science:

• Neurology
• Cerebrovascular Medicine
• Pharmacology

Background:

• Cerebrovascular occlusive disease can lead to chronic cerebral infarcts.
• The presence of hypoperfusion (ischaemic penumbra) surrounding these infarcts is hypothesized.
• Understanding this phenomenon is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the effects of nimodipine on regional cerebral blood flow (rCBF) and quantitative EEG in patients with cerebrovascular occlusive disease.
• To test the hypothesis of hypoperfusion in the vicinity of chronic cerebral infarcts.
• To evaluate nimodipine's potential to normalize peri-infarct hypoperfusion and improve neuronal function.

Main Methods:

• A study involving 13 patients with cerebrovascular occlusive disease.
• Measurements included regional cerebral blood flow (rCBF) using the 133Xe clearance method and quantitative EEG (sensorimotor rhythms).
• Nimodipine (a calcium channel blocker) was administered intravenously at 1 microgram/kg/min before and during measurements.

Main Results:

• In 3 patients, a significant redistribution of rCBF was observed, with increased flow in the peri-infarct zone (35 to 53 ml/100 g/min, p<0.01) and decreased flow elsewhere in the hemisphere.
• Parallel improvements in both rCBF and EEG were noted in these 3 patients.
• Individual improvements in sensorimotor rhythms (5 patients) and rCBF (3 patients) were also recorded.

Conclusions:

• Nimodipine administration demonstrated a potential to normalize peri-infarct hypoperfusion in patients with cerebrovascular occlusive disease.
• The observed parallel improvements in rCBF and EEG suggest a functional recovery due to nimodipine-induced reversal of flow-dependent neuronal silence or dysfunction.
• These findings support the concept of a reversible ischaemic penumbra surrounding chronic cerebral infarcts.