Table 1 Proposed staging system (adapted from McNamara and Hellman, unpublished clinical triaging system for ligation of a patent ductus arteriosus (PDA)) for determining the magnitude of the haemodynamically significant ductus arteriosus (HSDA), which is based on clinical and echocardiographic criteria.
| Clinical | Echocardiography | ||
|---|---|---|---|
| C1 | Asymptomatic | E1 | No evidence of ductal flow on two‐dimensional or Doppler interrogation |
| C2 | Mild | E2 | Small non‐significant ductus arteriosus |
| Oxygenation difficulty (OI <6) | Transductal diameter <1.5 mm | ||
| Occasional (<6) episodes of oxygen desaturation, | Restrictive continuous transductal flow (DA Vmax >2.0 m/s) | ||
| bradycardia or apnoea | No signs of left heart volume loading (eg, mitral regurgitant jet >2.0 m/s | ||
| Need for respiratory support (nCPAP) or mechanical | or LA:Ao ratio >1.5:1) | ||
| ventilation (MAP <8) | No signs of left heart pressure loading (eg, E/A ratio >1.0 or IVRT >50) | ||
| Feeding intolerance (>20% gastric aspirates) | Normal end‐organ (eg, superior mesenteric, middle cerebral) arterial | ||
| Radiologic evidence of increased pulmonary vascularity | diastolic flow | ||
| C3 | Moderate | E3 | Moderate HSDA |
| Oxygenation difficulty (OI 7–14) | Transductal diameter 1.5–3.0 mm | ||
| Frequent (hourly) episodes of oxygen desaturation, | Unrestrictive pulsatile transductal flow (DA Vmax<2.0 m/s) | ||
| bradycardia or apnoea | Mild‐moderate left heart volume loading (eg, LA:Ao ratio 1.5 to 2:1) | ||
| Increasing ventilation requirements (MAP 9–12) | Mild‐moderate left heart pressure loading (eg, E/A ratio >1.0 or | ||
| Inability to feed due to marked abdominal distension | IVRT 50–60) | ||
| or emesis | Decreased or absent diastolic flow in superior mesenteric artery, | ||
| Oliguria with mild elevation in plasma creatinine | Middle cerebral artery or renal artery | ||
| Systemic hypotension (low mean or diastolic BP) requiring | |||
| a single cardiotropic agent | |||
| Radiological evidence of cardiomegaly or pulmonary | |||
| oedema | |||
| Mild metabolic acidosis (pH 7.1–7.25 and/or | |||
| base deficit −7 to −12.0) | |||
| C4 | Severe | E4 | Large HSDA |
| Oxygenation difficulty (OI >15) | Transductal diameter >3.0 mm | ||
| High ventilation requirements (MAP >12) or need for | Unrestrictive pulsatile transductal flow | ||
| high‐frequency modes of ventilation | Severe left heart volume loading (eg, LA:Ao ratio >2:1, mitral regurgitant | ||
| Profound or recurrent pulmonary haemorrhage | jet >2.0 m/s) | ||
| “NEC‐like” abdominal distension with tenderness | Severe left heart pressure loading (eg, E/A ratio >1.5 or IVRT >60) | ||
| or erythema | Reversal of end‐diastolic flow in superior mesenteric artery, middle | ||
| Acute renal failure | cerebral artery or renal artery | ||
| Haemodynamic instability requiring >1 cardiotropic agent | |||
| Moderate‐severe metabolic acidosis (pH<7.1) or | |||
| base deficit >−12.0 | |||
BP, blood pressure; DA Vmax, ductus arteriosus peak velocity; E/A, early passive to late atrial contractile phase of transmitral filling ratio; IVRT, isovolumic relaxation time; LA: Ao ratio, left atrium to aortic ratio; MAP, mean airway pressure; nCPAP, nasal continuous positive airway pressure; NEC, necrotising enterocolitis; OI, oxygenation index.
Patients should be assigned both a clinical and echocardiography stage (eg, neonate with severe oxygenation failure, pulmonary haemorrhage and a 3.2 mm unrestrictive left‐to‐right shunt will be C4‐E4 class HSDA).
Detailed discussion of the echocardiography parameters is beyond the scope of this perspective.