(IV-1C.3.o) Patient with Taussig-Bing syndrome Drabik L., MD, Tomkiewicz-Pająk L., MD, PhD, Prof. Olszowska M., MD, PhD, Prof. Podolec P., MD, PhD

Background
Taussig-Bing syndrome is a rare congenital heart malformation consisting of transposition of the aorta to the right ventricle and malposition of the pulmonary artery with subpulmonary ventricular septal defect. Taussig-Bing syndrome is frequently associated with other cardiac abnormalities: right ventricular outflow tract obstruction, aortic arch obstruction and unusual coronary pattern [1].There are essential differences between Taussig-Bing syndrome and transposition of the great arteries with ventricular septal defect and overriding pulmonary artery. Taussig-Bing syndrome is characterized by true double-outlet right ventricle, semilunar valves side-by-side and approximately at the same height, absence of pulmonary–mitral continuity, and a large subpulmonary VSD [2].
Anatomic repair including connection of the morphologically left ventricle to the aorta and the morphologically right ventricle to the pulmonary artery is the treatment of choice. It is achieved with the arterial switch operation or interventricular repair (Kawashima operation). The palliative Senning and Mustard operations are less frequent. Prior to arterial switch operation pulmonary-artery banding, atrial septostomy, coarctation repair may be required. Some centers prefer single-stage total repair of all cardiac abnormalities. Patients with Taussig–Bing syndrome have a high risk of developing right ventricular outflow tract obstruction and aortic re-coarcation. Surgical management of RVOTO includes patch angioplasty of the pulmonary arteries, right ventricle – pulmonary artery conduit, infundibular muscle resection or and infundibular patch. Over the last two decades one-year survival in patients after anatomic repair increased from 47% to 100% and the 5-year event-free survival rates increased from 35% to 87% [3].

Case presentation
A 18-year-old man with complex congenital heart disease including double outlet right ventricle, D-malposition of the great arteries, subpulmonary ventricular septal defect, coarctation of the aorta, aortic arch hypoplasia, patent ductus arteriosus, subpulmonary outflow tract obstruction was admitted to our hospital. Previous surgery included: repair of aortic coarctation and arch hypoplasia (Gore-tex patch), patent ductus arteriosus ligation, balloon atrial septostomy and Senning procedure with closure of ventricular septal defect (24th-64th day of life), resection for subpulmonary outflow tract obstruction, conduit implantation between subpulmonary ventricle and the main pulmonary artery and epicardial VVIR pacemaker implantation due to postoperative third-degree atrioventricular block (3rd year of life), endocardial VVIR pacemaker implantation due to depleted battery (7th year of life), stent implantation to distal part of aortic arch and descending aorta for aortic recoarctation (16th year of life). Concomitant diseases included chronic hepatitis B. Current treatment included lamivudine, essential phospholipids. The patient remained asymptomatic. The patient was in good general condition. Physical examination revealed holosystolic murmur with a thrill at the base of the heart, no upper limb hypertension was observed. Non invasive pressure difference between upper and lower limbs was below 20mmHg. Laboratory and biochemical analysis were within normal ranges. Resting ECG showed right axis deviation, low atrial rhythm with a heart rate of 79 beats/minute, intraventricular conduction disturbances, right ventricular hypertrophy, negative T waves in I, avL, V5-V6. Holter monitoring revealed wide complex tachycardia 110bpm, duration 1,2s; ventricular premature beats (108), supraventricular premature beats (30).The cardiopulmonary exercise test showed reduced exercise tolerance and low maximal oxygen consumption (17,4 ml/kg/min), and elevated minute ventilation/carbon dioxide production slope (VE/VCO2 slope = 34,4 l/l). No pathological blood pressure response during exercise was observed.
The echocardiography revealed numerous abnormalities: enlargement and dysfunction of systemic ventricle (anatomical right ventricle), right-to-left systolic bulging of the interventricular septum, subpulmonary outflow tract obstruction with peak systolic gradient 84 mmHg. Peak gradient across the conduit between subpulmonary ventricle and the main pulmonary artery was about 30mmHg, right atrioventricular regurgitation velocity was 3,8m/s, peak gradient across the coarctation was 26mmHg, diastolic run-off wasn’t observed. CT scanning confirmed severe subpulmonary outflow tract obstruction (7x4mm), conduit between subpulmonary ventricle and the main pulmonary artery was not narrowed (12x10mm). Atrial baffle stenosis or leakage were excluded. Stent in the aortic arch and descending aorta was also not narrowed (15x15mm; aortic diameter at the diaphragm level was 23mm).

Current guidelines
Indications for intervention in patients with right ventricular to pulmonary artery conduits [4]
1. Symptomatic patients with right ventricular systolic pressure >60mmHg (tricuspid regurgitation velocity > 3,5 m/s, may be lower in case of reduced flow) and/or moderate/severe pulmonary regurgitation should undergo surgery [IC]
2. Asymptomatic patients with severe right ventricular outflow tract obstruction and/or severe pulmonary regurgitation should be considered for surgery when at least one of the following criteria is present:
• Decrease in exercise capacity (CPET)
• Progressive right ventricular dilation
• Progressive right ventricular systolic dysfunction
• Right ventricular systolic pressure >80mmHg (tricuspid regurgitation velocity > 3,4m/s)
• Sustained atrial/ventricular arrhythmias [IIaC]

Indications for intervention in coarctation of aorta [4]
1. Patients with a non-invasive pressure difference >20mmHg between upper and lower limbs, regardless of symptoms but with upper limb hypertension (>140/90 mmHg in adults), pathological blood pressure response during exercise, or significant left ventricular hypertrophy [IC]
2. Independent of the pressure gradient, hypertensive patients with ≥50% aortic narrowing relative to the aortic diameter at the diaphragm level (on CMR, CT or invasive angiography) [IIaC]
3. Independent of the pressure gradient and the presence of hypertension, patients with ≥50% aortic narrowing relative to the aortic diameter at the diaphragm level (on CMR, CT or invasive angiography) [IIbC]

Expert’s comments:(Written authorization required from each expert)

1. Anna Kabłak-Ziembicka, MD, PhD.¹
At the moment, the watchful policy with an optimal medical management for progressive heart failure and subsequent non-invasive assessment should be applied rather than surgical approach. I would recommend subsequent follow-up with transthoracic echocardiography test, 24-hour ECG monitoring and angiography with CT or MRI at 1-2 yearly intervals to evaluate eventual progression of the re-coarctation of aorta.

2. Prof. Janusz Skalski, MD, PhD.²
Conservative approach is advised. Non-invasive tests were helpful in exclusion of conduit narrowing and recoarctation. Dysfunction of the systemic ventricle is a late complication of the Senning procedure.

3. Prof. Lesław Szydłowski MD, PhD. ³
Surgical approach is not recommended now. In case of new symptoms arising reevaluation of indications for surgery is necessary.

Expert’s conclusions:
The patient was qualified for conservative treatment and regular follow-up.

Authors:
Drabik L., MD¹, Tomkiewicz-Pająk L., MD PhD¹, Prof. Olszowska M., MD, PhD¹, Prof. Podolec P., MD, PhD¹

Experts:
Anna Kabłak-Ziembicka, MD, PhD.¹, Prof. Janusz Skalski, MD, PhD.², Prof. Lesław Szydłowski MD, PhD.³

¹Department of Heart and Vascular Disease, John Paul II Hospital, Kraków, Poland
²Department of Pediatric Cardiac Surgery, Polish-American Children’s Hospital, Jagiellonian University, Krakow, Poland
³Department of Pediatric Cardiology, Medical University of Silesia, Katowice, Poland