This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Individuals with congenital heart disease often require surgery as infants. Surgery in such patients is frequently performed with the heart stopped and the patients' blood bypassing the heart and lungs. Following such procedures, infants are often very unstable, requiring significant support for many days. Maintaining adequate blood pressure and heart function can be particularly challenging. Some infants respond poorly to infusions of fluid and medicines used to elevate the blood pressure and support heart function. Studies in premature infants and critically ill infants have shown that inadequate blood pressure may be a result of the inability of the adrenal glands to produce steroid hormones in quantities sufficient to respond to periods of stress. Replacement of steroid hormones has led to elevation of blood pressure and clinical improvement in these studies. We have also used stress dose steroid hormones in infants with congenital heart disease who have undergone cardiac surgery and are persistently unresponsive to fluid infusion and escalating amounts of medicines that support the heart and elevate blood pressure. We have often observed a dramatic improvement in blood pressure and overall clinical well being, but such cases are anecdotal and have not been studied formally. We hypothesize that some infants with congenital heart defects who undergo cardiac surgery and require escalating blood pressure support have an inadequate response of the adrenal glands (relative adrenal insufficiency). We will evaluate the stress response of the adrenal glands in sixty infants following cardiac surgery. We will perform ACTH stimulation tests pre-operatively and post-operatively will measure the levels of certain steroid hormones, including cortisol, adrenocorticotropic hormone and aldosterone. The pre-operative ACTH stimulation response and post-operative hormone levels of the patients will be analyzed and correlated with clinical outcomes of the postoperative period.
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