Evaluation of Anomalous Systemic and Pulmonary Venous Return in a Young Child with Heterotaxy: A Case Study-Implications for Military Dependent Care

Military Medicine, Mar 2008 by Kinney, James Bedford, Gilman, Matthew David, Bolt, Stephen Laurence, Zenger, David Charles, Belser, Charlotte, Stillman, Charles Allen, Sahn, David Jonathan

ABSTRACT The case of a young male patient with a complex admixture lesion who required a comprehensive anatomic evaluation before palliative cardiac surgery is presented. We describe a safe anesthesia protocol for obtaining the late-acquisition, gadolinium-enhanced, magnetic resonance angiographic images necessary to define the complex pulmonary and systemic venous anatomic features of his cardiac admixture lesion. Subspecialty physician staffing implications for the care of military dependants with congenital heart disease who might benefit from evaluation using this safe simple protocol and readily available magnetic resonance imaging technology are addressed.

INTRODUCTION

Children with heterotaxy can have such complex cardiovascular anatomic features that they cannot be comprehensively evaluated with transthoracic echocardiography.1 Additionally, there are three typical challenges to the invasive diagnostic evaluation of heterotaxy that present significant barriers to traditional cardiac catheterization and accompanying angiography. These challenges are (1) the challenge of manipulating the catheter in the right atrium in the presence of anomalous systemic venous return or an interrupted inferior vena cava, (2) the challenge of identifying the precise anatomic features of partial anomalous pulmonary venous return, because of the progressive dilution of contrast material on the fluoroscopic image, and (3) the challenge of accurately mapping the exact site of entry to the right atrium of the hepatic circulation when there is interruption of the inferior vena cava. Furthermore, images from first-pass, gadolinium-enhanced angiography (supported with a short breath hold to ameliorate motion artifact) are acquired too early for the study of either pulmonary or systemic venous anatomic features, especially in an admixture lesion with a surgically created aortic pulmonary shunt. This requires a longer breath hold, especially for acquiring three-dimensional anatomic data.

We present the case of a young child with polysplenia who had limited venous access and whose treatment required careful study of born the pulmonary venous return and the hepatic venous circulation before surgery. We describe a simplified, safe, prolonged breath-hold technique developed over a 10-year period at Madigan Army Medical Center, which yielded high-quality, late-acquisition, magnetic resonance angiographic images needed for planning this child's successful surgical treatment2,3 (Figs. 1-3).

CASE REPORT

The patient was a 3-year-old African American boy who presented with unexplained cyanosis as a newborn. He was transferred to a tertiary care medical center, where an echocardiographic evaluation established the diagnosis of complex cyanotic congenital heart disease. Cardiac catiieterization resulted in the following diagnoses: dextrocardia, situs ambiguous, double-outlet right ventricle, L-malpositioned aorta, critical infundibular and valvular pulmonary stenosis, interruption of the inferior vena cava, small left ventricle with unrestrictive ventricular septal defect, and probable partial anomalous pulmonary venous return to the right atrium. A 3.5-mm Gore-Tex shunt was surgically placed between the main pulmonary artery and the underside of the aortic arch, resulting in sufficient pulmonary perfusion to provide oxygen saturation values of ~80% to ~84%, adequate for normal growth and development. At 8 months of life, the patient's care was transferred to Madigan Army Medical Center, where it became necessary for the patient's new physicians to plan for surgical repair before reassignment of the active duty soldier parents.

The patient was referred to a regional center for the surgical care of children with heart disease, where a review resulted in a request for the referring cardiologists at Madigan Army Medical Center to determine (1) the adequacy of the left ventricle, (2) the exact anatomic features of the anomalous pulmonary and systemic venous return, and (3) the location of the hepatic drainage to the right atrium, with attention to its proximity to the site of return for the left-sided anomalous pulmonary veins (did the hepatic circulation and the anomalous left-sided pulmonary venous return enter the right atrium separately or together?). The patient was taken to the magnetic resonance imaging (MRI) suite. There, anesthesia was induced with inhalation of oxygen/sevoflurane, an intravenous line was placed in the right antecubital vein, the patient was given 1.5 mg/kg propofol intravenously, and a laryngeal mask airway was inserted. Heart rate, oxygen saturation, blood pressure, and end-tidal pCO^sub 2^ were monitored in the usual fashion. The child was placed in a 1.5-T MRI scanner (GE Signa; GE Medical Systems, Milwaukee, Wisconsin), and administration of propofol at 100 to 200 µg/kg per minute was maintained for the duration of the MRI procedure.

The initial evaluation of the cardiac anatomic features was performed with routine, T1-weighted, axial sequences in the 1.5-T scanner. The Gore-Tex shunt was identified, basic anatomic diagnoses were confirmed, polysplenia was documented, and special attention was paid to a small, clearly inadequate, left ventricle, which made the necessity for a Fontan-type repair readily apparent; therefore, accurately documenting the pulmonary venous return and systemic venous return was essential. For successful surgery, gadolinium-enhanced magnetic resonance angiography (three-dimensional, time-of-flight, magnetic resonance angiography) would be the modality of choice.