Imaging of pulmonary venous pathway obstruction in patients after the modified Fontan procedure

Protein-losing enteropathy managed with percutaneous enlargement of a restrictive atrial septal defect

Protein-losing enteropathy is one of the most feared complications of the Fontan circulation. The diagnosis of protein-losing enteropathy in this setting should prompt a thorough investigation for the presence of a treatable hemodynamic impairment. In this report, we describe a complete reversal of protein-losing enteropathy following percutaneous enlargement of a restrictive atrial septal defect in a patient with a fenestrated lateral tunnel Fontan and severe mitral stenosis.

Pulmonary venous obstruction after extracardiac total cavopulmonary connection in right atrial isomerism

BACKGROUND

Patients with functional single ventricle and right atrial isomerism (RAI) often have multiform cardiac pulmonary venous (PV) connection, which could be a risk factor for pulmonary venous obstruction (PVO) after extracardiac total cavopulmonary connection (EC-TCPC) owing to compression of the conduit.

OBJECTIVE

To investigate the anatomical risk factors for PVO after EC-TCPC in RAI.

METHODS

Twenty-nine patients with RAI without extracardiac total anomalous pulmonary venous connection were enrolled. No patients had PVO before EC-TCPC. A total of 14 and 15 patients had PV orifices ipsilateral and contralateral to the extracardiac conduit, respectively. The former 14 patients were assigned to two groups based on development of PVO after EC-TCPC (groups O and N). The pre- and post-operative cardiac morphologies and their relationship with the conduit were compared.

RESULTS

After the EC-TCPC, the pressure gradients between the atrium and the PV were 5.0 ± 2.5 and 0.44 ± 0.2 mmHg in groups O and N, respectively (p < 0.01); however, the pressure gradients in the left and right PVs were not significantly different, suggesting stenosis of the common PV orifice. The ratio of the horizontal distance from the vertebrae to the PV orifice and to the lateral edge of the atrium was significantly higher (0.38 ± 0.2 vs. 0.17 ± 0.1; p = 0.04) and the orifice was smaller (8.9 ± 2.0 vs. 15 ± 4.7 mm; p < 0.01) in group O than in group N.

CONCLUSION

In cases with ipsilateral locations of the conduit and PV orifice, small size and more lateral location of the PV orifice may be preoperative risk factors for development of PVO.

Insights After 40 Years of the Fontan Operation

Fontan’s visionary operation and its modifications over the ensuing decades have re-established nonturbulent flow and substantially reduced cyanosis for patients with severe hypoplasia of one ventricle. However, a long list of largely unexpected sequelae has emerged over the last 40 years. Although it is not difficult to understand how care providers could become discouraged, a number of myths have arisen, which we will attempt to dispel with real-world counterexamples as well as with lessons learned from other disciplines: evolutionary, developmental, and computational biology. We argue that distinctive biochemical abnormalities pointing to dysfunction in multiple organs, including the largest organ system in the body, the endothelium, occur long before grossly observable changes in cardiac imaging can be recognized. With a rational redesign of both our surveillance scheme and our wellness strategies, we hope that Fontan survivors and their families, as well as physicians, nurses, and therapists, will see why Fontan’s principle remains just as vibrant today as it was in 1971.

Restrictive interatrial communication in hypoplastic left heart syndrome after modified Fontan repair

The occurrence of pulmonary venous obstruction after total cavopulmonary connection with intraatrial lateral tunnel is a rare occurrence. We present two cases of hypoplastic left heart syndrome with restrictive interatrial communication presenting late after this type of modified Fontan repair. This occurred even after complete excision of the atrial septum at the time of Stage 1 Norwood in both cases. A novel approach to this problem of resecting the roof of the coronary sinus was utilized to enlarge the interatrial communication.

Pulmonary venous obstruction after total cavopulmonary connection in heterotaxy

Pulmonary venous obstruction is a rare complication after total cavopulmonary connection by intraatrial grafting. We experienced this complication in two patients. In one of them, a large prosthesis produced inflow obstruction of the dominant ventricle and was successfully replaced with a smaller tube. In the other patient, the intraatrial tube had become severely adherent to the common pulmonary venous orifice and was removed entirely. Conversion to an extracardiac Fontan circulation was later successfully established.

The nature of flow in the systemic venous pathway measured by magnetic resonance blood tagging in patients having the Fontan operation

OBJECTIVES

Our objectives were twofold: (1) to determine cardiac and respiratory dependency of systemic venous pathway flow of patients having the Fontan operation with a total cavopulmonary connection and (2) to describe the velocity profile. Systemic venous pathway flow is hypothesized to be mostly respiratory dependent, to be laminar, and to have a smooth velocity profile.

METHODS

Twenty-two patients having the Fontan operation (aged 8.6 +/- 4.7 years) underwent magnetic resonance blood tagging (bolus tagging). Systemic venous pathway spin-echo images parallel to the blood flow were used as a localizer. A saturation pulse labeled the blood, and a cine image was acquired at the inferior and superior venae cavae and midportion of the baffle in the systemic venous pathway, triggered to the electrocardiogram and gated to both end-expiration and end-inspiration. Repetition time was 50 msec.

RESULTS

Flow in the systemic venous pathway was laminar throughout its course and was found to be phasic to both cardiac and respiratory cycles. Approximately 70% of flow was cardiac dependent, and the rest was respiratory. Highest flow occurred near end-systole and early diastole and in inspiration. Lowest flow occurred in diastasis. Velocity was highest and flow least "pluglike" in the mid-baffle area during cardiac or respiratory imaging (45 +/- 17 and 32 +/- 11 cm/sec, respectively).

CONCLUSION

A substantial amount of pulmonary blood flow in patients who have undergone a total cavopulmonary connection type of Fontan operation has a cardiac component. Furthermore, we confirm that this flow is laminar but nonuniform across the systemic venous pathway. Highest flows occurred near end-systole and early diastole, as well as in inspiration, and the lowest flow occurred in diastasis. This information may help in designing the systemic venous pathway and optimizing medical management.

Aortic Stenosis or Atresia with Associated Hypoplasia of the Left Ventricle: Imaging Before and After Reconstructive Surgery

Aortic atresia or stenosis, when associated with hypoplasia of the left ventricle, presents the cardiac surgeon with a challenging reconstruction. Many preoperative and intraoperative decisions are now made on the basis of ultrasound data. Furthermore, echocardiography provides the most convenient way to time the stages of the reconstructive sequence and assess the hemodynamic result. (ECHOCARDIOGRAPHY, Volume 13, May 1996)

Changes in pulmonary venous flow pattern during early neonatal life

OBJECTIVE

To investigate serial changes in the pattern of flow in the pulmonary vein during the early neonatal period.

METHODS

Pulsed Doppler echocardiography was used to measure flow in the right upper pulmonary vein in 26 normal newborn infants. Peak flow velocity during systole (S) and diastole (D) and flow velocity at indents between the systolic and diastolic fraction (O) and between the diastolic and systolic fraction (X) were measured 1, 4-8, 24, and 96 hours after birth. The heart rate and diameter of the ductus arteriosus were measured simultaneously.

RESULTS

Continuous and phasic high flow velocity waveforms were seen 1 and 4-8 hours after birth. The mean (SD) peak flow velocities of X, S, O, and D an hour after birth were 35.2 (13.6) cm/s, 73.1 (23.1) cm/s, 58.5 (20.5) cm/s, and 81.5 (19.2) cm/s respectively. There were significant decreases in X, S, O, and D by 24 hours of age (p < 0.01 v 1 hour after birth) to 8.1 (10.3) cm/s, 52.8 (18.0) cm/s, 38.6 (14.5) cm/s, and 54.4 (11.2) cm/s respectively. These results indicate intermittent flow in the pulmonary vein, with flow stopping between diastole and systole. These flow velocities, X, S, O, and D, correlated well with the diameter of the ductus arteriosus (r = 0.80 v X, r = 0.62 v S, r = 0.63 v O, r = 0.75 v D).

CONCLUSION

This serial study showed changes in normal pulmonary vein flow patterns during the early neonatal period. The continuous and high flow velocity waveform that was seen immediately after birth resembled the pattern of pulmonary vein flow seen in congenital pulmonary stenosis and in cases of acute volume overload. This waveform may reflect a sudden increase in pulmonary circulatory volume with additional left to right shunting through the ductus arteriosus in relatively hypoplastic pulmonary veins.