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Changes in cerebral blood flow in patients with severe congestive cardiac failure before and after captopril
Insights
Severe heart failure reduces cerebral blood flow. Treatment with captopril, an angiotensin-converting enzyme inhibitor, significantly restored cerebral blood flow in patients with severe heart failure.
Area of Science:
- Cardiology
- Neurology
- Pharmacology
Background:
- Severe heart failure is associated with reduced cerebral blood flow.
- The impact of heart failure on brain perfusion requires further investigation.
Purpose of the Study:
- To evaluate the effect of captopril on global cerebral blood flow in patients with severe heart failure.
- To determine if captopril treatment can restore reduced cerebral blood flow in this patient population.
Main Methods:
- Intravenous 133xenon injection method used to measure global cerebral blood flow.
- Measurements taken before and after treatment with captopril in nine patients.
- Blood pressure and end-tidal carbon dioxide levels monitored.
Main Results:
- Pretreatment cerebral blood flow (61.1 ml/100 g/min) was significantly lower than in control subjects (75.8 ml/100 g/min).
- Captopril treatment (4-15 days) reduced mean blood pressure and increased cerebral blood flow to 73.8 ml/100 g/min (p < 0.01).
- No significant change in end-tidal carbon dioxide fraction was observed.
Conclusions:
- Cerebral blood flow is diminished in severe heart failure.
- Captopril treatment can restore cerebral blood flow in these patients.
- The precise mechanisms underlying reduced flow and its improvement with ACE inhibition remain unclear.
Abstract:
The intravenous 133xenon injection method was used to estimate global cerebral blood flow before and after treatment with captopril in nine patients with severe heart failure. The pretreatment mean blood pressure was 94.9 mm Hg (S.D. 13.9) and fell to 85.1 mm Hg (S.D. 18.1) after treatment with captopril for between four and 15 days. The cerebral blood flow before captopril was 61.1 ml/100 g per minute (S.D. 6.9), which was less than the value of 75.8 ml/100 g per minute found in control subjects. After treatment with captopril the cerebral blood flow increased to 73.8 ml/100 g per minute (S.D. 11.8, p less than 0.01). The fraction of carbon dioxide in the expired air was not significantly different in the two studies (4.1 +/- 0.88 versus 3.97 +/- 0.65). It is concluded that cerebral blood flow is reduced in severe heart failure and can be restored by treatment with captopril, but the reasons for the reduced flow and its improvement after converting enzyme inhibition are not known.