Critical Congenital Cardiovascular Disease: Extent of the Problem
Congenital cardiovascular disease occurs in about 1% of live births (excluding bicuspid aortic valve and hemodynamically insignificant lesions, such as very small secundum atrial and muscular ventricular septal defects). Congenital cardiovascular disease is considered to be critical if it will predictably result in death or severe morbidity if unrecognized and not treated in early infancy. These conditions often depend on patency of the ductus arteriosus to maintain either pulmonary or systemic blood flow. Signs of severe cyanosis or progressive heart failure leading to cardiovascular collapse develop as the ductus arteriosus constricts during the first few days or weeks after birth. It is important to recognize that a newborn with critical congenital cardiovascular disease may show little evidence of cardiovascular compromise on physical examination in the first 24 to 48 hours of life. Cardiovascular instability may not occur until after the infant is discharged from the hospital. The recent addition of routine pulse oximetry screening in many hospitals should greatly enhance our ability to diagnose such infants before discharge and thus decrease the number who present critically ill in the days and weeks after discharge.
The National Vital Statistic Report reported 3,932,181 registered births in the United States in 2013, which means that about 40,000 infants were born with heart defects. Of the 25% to 30% of infants with heart defects, at least 10,000 are predicted to have critical disease. Diagnosis before the onset of cardiovascular decompensation is essential for optimal outcome. In the absence of detection during fetal life by ultrasound examination or pulse oximetry screening after birth, about 70% of infants with critical congenital cardiovascular disease are not diagnosed before 2 days of age. This leads to severe morbidity and mortality in many hundreds of newborns each year in the United States alone, at a large social and economic cost. Thus, it is incumbent on all physicians and other health care professionals who care for newborns to rigorously evaluate every newborn for the possibility of critical cardiovascular disease. Furthermore, if there is any indication that such disease might exist, the infant must be referred for further evaluation without delay.
Presentation of Congenital Cardiovascular Disease: An Overview
The evaluation of the infant for critical cardiovascular disease should focus on the three cardinal signs of neonatal cardiovascular distress: cyanosis, decreased systemic perfusion, and tachypnea. Cyanosis may be appreciated by careful visual inspection and pulse oximetry, decreased systemic perfusion is identified by examination of the extremities, and tachypnea is noted by observing the respiratory rate and pattern. The presence of a congenital cardiovascular defect (or, less commonly, a cardiomyopathy or arrhythmia) must be considered in the differential diagnosis of any infant with one or more of these findings. A cyanotic infant most likely has underlying cardiovascular disease and almost certainly does in the absence of significant respiratory distress. An ...