Cerebral blood flow autoregulation in ischemic heart failure

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology Vol. 312; no. 1; pp. R108 - R113
• Main Authors: Caldas, J. R., Panerai, R. B., Haunton, V. J., Almeida, J. P., Ferreira, G. S. R., Camara, L., Nogueira, R. C., Bor-Seng-Shu, E., Oliveira, M. L., Groehs, R. R. V., Ferreira-Santos, L., Teixeira, M. J., Galas, F. R. B. G., Robinson, T. G., Jatene, F. B., Hajjar, L. A.
• Format: Journal Article
• Language: English
• Published: United States 01.01.2017
• Subjects: Blood Flow Velocity; Cerebrovascular Circulation; Cerebrovascular Disorders - etiology; Cerebrovascular Disorders - physiopathology; Female; Heart Failure - complications; Heart Failure - physiopathology; Homeostasis; Humans; Male; Middle Aged; Myocardial Ischemia - complications; Myocardial Ischemia - physiopathology; dynamic cerebral autoregulation; cerebral blood flow; transcranial Doppler; transfer function analysis; autoregulation index
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.00361.2016

Patients with ischemic heart failure (iHF) have a high risk of neurological complications such as cognitive impairment and stroke. We hypothesized that iHF patients have a higher incidence of impaired dynamic cerebral autoregulation (dCA). Adult patients with iHF and healthy volunteers were included. Cerebral blood flow velocity (CBFV, transcranial Doppler, middle cerebral artery), end-tidal CO 2 (capnography), and arterial blood pressure (Finometer) were continuously recorded supine for 5 min at rest. Autoregulation index (ARI) was estimated from the CBFV step response derived by transfer function analysis using standard template curves. Fifty-two iHF patients and 54 age-, gender-, and BP-matched healthy volunteers were studied. Echocardiogram ejection fraction was 40 (20–45) % in iHF group. iHF patients compared with control subjects had reduced end-tidal CO 2 (34.1 ± 3.7 vs. 38.3 ± 4.0 mmHg, P < 0.001) and lower ARI values (5.1 ± 1.6 vs. 5.9 ± 1.0, P = 0.012). ARI <4, suggestive of impaired CA, was more common in iHF patients (28.8 vs. 7.4%, P = 0.004). These results confirm that iHF patients are more likely to have impaired dCA compared with age-matched controls. The relationship between impaired dCA and neurological complications in iHF patients deserves further investigation.