Interventional PDA-closure, including PPC or surgical ligation and post-randomization pharmacologic (NSAID or acetaminophen) (enteral or intravenous) PDA treatment, are not allowed unless secondary treatment thresholds (see below) are met. Healthcare decisions for Responsive Management will be made at the discretion of the treatment team, while the infant is carefully monitored for any decline in status that may be attributed to the presence of PDA, in which case, Secondary Intervention (described below) may be considered.

Despite widespread acceptance of responsive PDA management, no consensus definition exists. The following Responsive Management interventions are permitted but not required per clinician discretion: 1) fluid restriction between 120-140 mL/kg/day; 2) diuretics (per local practice); 3) increases in positive end-expiratory pressure (PEEP).

An echocardiogram, also known as "ECHO", is an ultrasound image of the heart. Echocardiography is a common test used for the diagnosis and management of cardiac diseases or conditions.

A compositve binary outcome measure (yes/no), diagnosis of pulmonary hypertension will be determined by cardiac echocardiogram at 36 weeks post-menstrual age. Diagnosis of pulmonary hypertension is an indicator of increased pulmonary vasculature resistance, a marker for increased morbidity and mortality among infants with chronic lung disease.

The total number of days (continuous variable) a study subject requires any use of invasive mechanical ventilatory support within a 24-hour calendar day.

The sum of days the study subject requires either invasive or non-invasive positive pressure assisted ventilation within a 24 hour calendar day.

Total number of days the study subject requires supplemental oxygen. The subject may be on either invasive or non-invasive ventilatory support during this time. The subject must be free from supplemental oxygen use for a period of at least 24 hours to interrupt or cease counting.

A continuous measure, in days, of the time from a study subject's randomization to expiration, if this occurs.

A diagnosis of left-ventricular output by echocardiography (ECHO) at 36 weeks post-menstrual age.

Finding of left-ventricular end-diastolic volume (LV EDV) >97% on echocardiography (ECHO) at 36 weeks post-menstrual age.

The General Movements Assessment (GMA) is a standardized video-based neurological exam to evaluate the presence of "fidgety" versus "absent fidgety" and "cramped-synchronized" versus "non cramped-synchronized" movement patterns at 34 - 36 weeks post-menstrual age. It is used to assist in the diagnosis of impaired motor neurodevelopment and cerebral palsy.

Recording of incidence of need for study subjects randomized to Responsive Management to undergo Percutaneous Patent Ductus Arteriosus Closure (PPC) due to decline in health status.

The HNNE is a standardized neurological examination of 34 items to evaluate tone, motor patterns, spontaneous movements, reflexes, visual and auditory attention, and behavior.

The HINE is similar to the HNNE, used to assess neurological function at 3 - 24 months of age, including cranial nerve function, movements, reflexes, protective reactions and behavior, and age-dependent evaluation of gross and fine-motor function.

Caregiver questionnaire responses to determine if their infant appropriately processes and responds to environmental stimuli, versus missing or taking longer to respond ("Low Registration"). There are 13 items with scores of 13 - 65 possible; scores of 42 - 51 are considered "Typical performance".

Caregiver questionnaire responses to determine if their infant is hyposensitive, seeking additional sensory stimulation. There are 6 items with scores of 6 - 30 possible; scores of 7 - 15 are considered "Typical performance".

Caregiver questionnaire responses to determine if their infant responds readily to sensory stimulation, without actively avoiding it. There are 12 items with scores of 12 - 60 possible; scores of 45 - 57 are considered "Typical performance)

Caregiver questionnaire responses to determine if their infant avoids sensory stimulation. There are 5 items with scores of 5 - 25 possible; scores of 19 - 25 are considered "Typical performance".

Caregiver questionnaire responses which are the sum of the Sensory Sensitivity and Sensation Avoiding domains). Summed scores of 15 - 85 are possible; summed scores of 64 - 81 are considered "Typical performance".

The BCQ is another caregiver-based questionnaire for parental perspectives of an infant's feeding and sleeping habits. It is used as an evaluation of a parent's reliance upon structure / routines and attunement (dependence upon infant's cues).

The MIBS is an 8-item questionnaire to evaluate a mother's bondedness towards her infant. Responses are scored from 0 to 3 for each item, with a total possible range of 0 - 24. Lower scores indicate more favorable outcomes for mother-infant bondedness, whereas higher scores indicate the potential for difficulties.

Reporting of type and frequency of any adverse event that occurs during percutaneous closure procedures, and post-procedurally that may be related to the intervention.

Reporting of type and frequency of any serious adverse event (e.g., potentially life-threatening change in status) that occurs during percutaneous closure procedures, and post-procedurally that may be related to the intervention.

Examination of the homogeneity of the effect of HSPDA on the primary and secondary outcomes will be carried out in statistical analyses using stratification variables (e.g., gender, gestational age, etc.) and characteristics not balanced through random assignment, if any such imbalances are found.