Objective: To compare CBFV in SGA infants to 2 groups of appropriate for gestational age (AGA) infants, matched for birth weight (BW) or GA. Methods: CBFV was studied in the anterior (ACA), and the middle cerebral arteries (MCA) of 76 (11=SGA, 65=AGA) ventilated, stable infants, with no echocardiographic evidence of a PDA. A total of 127 scans were performed. Infants with haematocrit ≤30 or ≥65%, PCO, ≤30 or≥65mmHg, and ventilatory index (rate × inspiratory pressure) ≥ 800 were excluded. CBFV was measured as previously described (Pediatr Radiol 1991;21:395). Mean velocity (MV), and pulsatility index (PI) in SGA infants were compared to AGA control groups at 0-3, 4-7, 8-15 and ≥21 days postnatal age. Matching was done for one comparison by BW and for the other by GA. Statistical analyses were done by Student's t test. Results: The mean GA of the SGA infants was 29±2 (range 26-31) wks, the mean BW was 816±230 (range 485-1120)g. The mean GA of the AGA BW matched group was 27±1 wks, and the mean BW of the GA matched group was 1171±275 g. There were no significant differences between the groups at any time (p>0.2). The results at 0-3 days are presented in the table. There was a significant difference between MV in ACA and MCA within all groups (p<0.001).
Conclusion: We found no difference in CBFV in the ACA and MCA between SGA and AGA infants. This is in contrast to previous studies showing increased CBFV in SGA infants. The MV is significantly higher in the MCA compared to the ACA in all groups of infants. Any difference in the risk for intracranial pathology in preterm SGA infants can not be explained by a difference in CBFV. The difference in risk for intracranial pathology between SGA and AGA infants deserve further studies. (Supported by Garfield Weston Foundation & Advanced Technology Labs.)
