Some infants are born with congenital heart defects and require surgery very early in life. One approach to performing this surgery is known as “circulatory arrest.” A downside of this procedure, however, is that it cuts off the flow of blood to the brain, possibly resulting in brain damage. An alternative procedure, “low-flow bypass” maintains circulation to the brain, but does so with an external pump that potentially causes other sorts of injuries to the brain.
To investigate the treatments, surgeons at Harvard Medical School conducted a randomized controlled trial. In the trial, 70 infants received low-flow bypass surgery and 73 received the circulatory arrest approach. The researchers looked at two outcomes: the Psychomotor Development Index (PDI), which measures physiological development, and the Mental Development Index (MDI), which measures mental development. For both indices, higher scores indicate greater levels of development.
Treatment: Treatment group (Circulatory arrest, Low-flow bypass)PDI: Psychomotor Development IndexMDI: Mental Development IndexBellinger DC, Jonas RA, Rappaport LA, Wypij D, Wernovsky G, Kuban KCK, Barnes PD, Holmes GL, Hickey PR, Strand RD, Walsh AZ, Helmers SL, Constantinou JE, Carrazana EJ, Mayer JE, Hanley FL, Castaneda AR, Ware JH, and Newburger JW. (1995). Developmental and Neurologic Status of Children after Heart Surgery with Hypothermic Circulatory Arrest or Low-Flow Cardiopulmonary Bypass. New England Journal of Medicine, 332: 549-555.