Functional pulmonary atresia: color flow recognition and treatment with extracorporeal membrane oxygenation

Doppler echocardiographic differentiation of functional from anatomical pulmonary atresia: analysis using quantitative parameters

Functional pulmonary atresia must be distinguished from anatomical atresia, which has an intact ventricular septum, to avoid inappropriate treatment, but there is a paucity of data regarding the echocardiographic features that differentiate these conditions. Echocardiographic findings in 5 neonates with functional atresia were compared to those in 5 with anatomical atresia. The left and right ventricular end-diastolic dimensions (LVDd, RVDd), percent of normal predicted LVDd, RVDd/LVDd, tricuspid valve ring diameter (TVD), percent of normal predicted TVD, grade of tricuspid regurgitation (TR), peak TR velocity, pulmonary valve ring diameter (PVD), percent of normal predicted PVD, the minimum diameter of the ductus and the peak velocity through it (PDA velocity) were measured. In addition, systolic pulmonary (PAp) and right ventricular pressure (RVp) from either PDA velocity or TR velocity, and calculated PAp/RVp were also estimated. There were significant differences in RVDd/LVDd, %TVD, and peak TR velocity between the 2 groups. All functional patients showed RVDd/LVDd >0.6, %TVD >100%, estimated RVp <50mmHg, PAp/RVp >0.85, and peak TR velocity <4m/s, whereas the findings in anatomical atresia patients were completely the opposite. In conclusion, a large RVDd/LVDd, TVD, PAp/RVp, low RVp and small TR velocity all suggest functional rather than anatomical pulmonary atresia, although there may be some exceptions such as severe Ebstein anomaly.

Recognition of functional pulmonary atresia by color Doppler echocardiography

Vigorous crying aids right ventricular ejection into the pulmonary artery. This phenomenon can differentiate functional pulmonary atresia from anatomic pulmonary atresia.

Preoperative ECMO in congenital cyanotic heart disease using the AREC system

BACKGROUND

In cyanotic congenital heart disease, oxygen delivery is impaired either by reduced pulmonary perfusion or by limited entry of oxygenated blood into the systemic circulation. Additional impairment of oxygen delivery (eg, in pulmonary hypertension) leads to hypoxic cerebral damage. Preoperative extracorporeal membrane oxygenation enables oxygenation in otherwise untreatable cases.

METHODS

In 3 neonates suffering from cyanotic congenital heart disease (1 with tricuspid atresia and 2 with transposition of the great arteries) with arterial desaturation despite application of prostaglandins, balloon atrioseptostomy, and eventually inhaled nitric oxide during intermittent positive-pressure ventilation with an inspired oxygen fraction of 1, oxygenation could only be established by means of preoperative extracorporeal membrane oxygenation. We used a venovenous single-lumen cannula tidal-flow extracorporeal membrane oxygenation system described by Chevalier and associates that has previously been used for extracorporeal lung support. In this system, called AREC (assistence respiratoire extra-corporelle), alternating clamps and a nonocclusive roller pump were used.

RESULTS

All 3 survived.

CONCLUSIONS

We conclude that the AREC system enables sufficient preoperative oxygenation in patients with cyanotic congenital heart disease and hypoxia in spite of all conventional therapeutic means. This provides a stable preoperative condition for elective palliation or correction.

Extracorporeal life support in cyanotic congenital heart disease before cardiovascular operation

From July 1988 to March 1991, extracorporeal membrane oxygenation (ECMO) was used in 8 infants (newborn to 16 months old) with unoperated cyanotic congenital heart disease and cardiopulmonary collapse, associated with hypercyanotic spells (4 infants), pulmonary hypertensive crises (3) and sepsis (1). Indications for ECMO support were arterial saturations less than or equal to 60% accompanied by hypotension and metabolic acidosis unresponsive to mechanical ventilation with 100% oxygen, paralysis and sedation, and pharmacologic support with inotropes or vasodilators, or both. Venoarterial bypass by carotid/jugular cannulation with flow rates of 100 to 840 ml/kg/min (mean 460) stabilized all patients. Duration of ECMO support ranged from 15 to 840 hours and was associated with transient seizures (1 patient) and renal failure (1). Seven patients underwent palliative (3 patients) or corrective (4) surgical procedures while on ECMO or within 48 hours of decannulation, including 1 patient bridged to double-lung transplantation with a long (840 hours) duration of ECMO. There was 1 operative and 2 late (greater than 1 month after decannulation) deaths, for an overall survival rate of 62%. These 5 survivors all have normal growth and development, and patent neck vessels at the site of cannulation. These early results indicate that ECMO can be effective mechanical support in cardiovascular crises untreatable with maximal conventional medical therapy and can be used as a bridge to successful surgical palliation or repair.