Circulatory Insufficiency and Hypotension Related to the Ductus Arteriosus in Neonates

Abstract

The biological role of the ductus arteriosus (DA) in neonates varies from an innocent bystander role during normal postnatal transition, to a supportive role when there is compromise to either systemic or pulmonary blood flow, to a pathological state in the presence of hemodynamically significant systemic to pulmonary shunts, as occurs in low birth weight infants. Among a wide array of clinical manifestations arising due to the ductal entity, systemic circulatory insufficiency and hypotension are of significant concern as they are particularly challenging to manage. An understanding of the physiologic interplay between the DA and the circulatory system is the key to developing appropriate targeted therapeutic strategies. In this review, we discuss the relationship of systemic hypotension to the DA, emphasizing the importance of critical thinking and a precise individual approach to intensive care support. We particularly focus on the variable states of hypotension arising directly due to a hemodynamically significant DA or seen in the period following successful surgical ligation. In addition, we explore the mechanistic contributions of the ductus to circulatory insufficiency that may manifest during the transitional period, states of maladapted transition (such as acute pulmonary hypertension of the newborn), and congenital heart disease (both ductal dependent and non-ductal dependent lesions). Understanding the dynamic modulator role of the ductus according to the ambient physiology enables a more precise approach to management. We review the pathophysiology, clinical manifestations, diagnosis, monitoring, and therapeutic intervention for the spectrum of DA-related circulatory compromise.

Keywords: ductus arteriosus; echocardiography; hemodynamics; hypotension; shunt volume.

Figure 1

Relationship between circulatory instability and the ductus arteriosus (DA) in neonates. Acute PH, acute pulmonary hypertension of newborn; CHD, congenital heart disease; hsDA, hemodynamic significant DA; PLCS, post-ligation cardiac syndrome.

Figure 2

Algorithm for the assessment and treatment of ductus arteriosus (DA)-associated hypotension according to systolic, diastolic, and combined systolic and diastolic categories. *Global assessment of systemic perfusion from integration with arterial pressure thresholds may provide early clinical insights regarding pathophysiologic determinants of hemodynamic instability, but ascertainment and confirmation of the presence of hemodynamics significance must be obtained using comprehensive echocardiography.

Figure 3

Hemodynamic alterations and clinical algorithm following patent DA (PDA) ligation. L to R, left to right; GA, gestational age; SAP, systolic arterial pressure; DAP, diastolic arterial pressure; PLCS, post-ligation cardiac syndrome. *Transient hypertension, with a predominant increase in diastolic blood pressure, has also been observed in the immediate postoperative period following PDA ligation (75), lasting for a variable amount of time, but rarely beyond the first 24–48 h post-ligation. Persistent hypertension lasting days or weeks and hypertension needing treatment are relatively rare complications, with only a few cases reported in infants and older children (76, 77). Post-PDA treatment hypertension is ascribed to the increased systemic vascular resistance (SVR), resulting from sudden obliteration of the low-resistance ductal pathway, along with some degree of vasomotor dysregulation in the presence of maintained myocardial performance. **Consider hydrocortisone (refractory hypotension with adrenal insufficiency) with systolic and/or diastolic hypotension.