Complete repair in total atrioventricular canal defect with cyanosis

Abstracts

Atrioventricular septal defects account for 4% of congenital cardiac malformations and over 50% of cardiac defects seen in Down syndrome¹. Clinical presentation is marked by congestive heart failure early in infancy. Cyanosis is rarely found in infants and suggests irreversible pulmonary hypertension or associated cardiac defects as tetralogy of Fallot, double outlet right ventricle², Ebstein anomaly³, persistent left superior vena cava draining in the left atrium (Barbero Marcial, personal communication). Children with Down's syndrome is particularly difficult to assess because they often suffer from upper airways obstruction4, which may contribute to the increased pulmonary vascular resistance determined at cardiac catheterization. This association of factors becomes a challenge for operability and, we will report one such case.

Complete atrioventricular septal defect; cyanosis; surgical repair

Os defeitos do septo atrioventricular total (DSAVT) representam 4% das mal formações cardíacas e acima de 50% dos defeitos observados na síndrome de Down (SD)¹. A apresentação clínica é de insuficiência cardíaca precoce na infância e hipertensão pulmonar por hiperfluxo. Raramente a cianose é observada e sugere hipertensão pulmonar ou associação à tetralogia de Fallot³, dupla via de saída de ventrículo direito², anomalia de Ebstein4, drenagem anômala de cava esquerda persistente em átrio esquerdo (Barbero Marcial, comunicação pessoal). Crianças com SD são particularmente difíceis de avaliação por apresentarem obstrução de vias aéreas superiores, que podem contribuir com o aumento da resistência pulmonar observada no cateterismo cardíaco. A presença de cianose pré-operatória constitui-se um desafio ao tratamento cirúrgico devido ao risco de hipertensão pulmonar irreversível com falência ventricular direita com, a correção dos defeitos intracardíacos.

Septo atrioventricular total; cyanosis; correção total

CASE REPORT

Complete repair in total atrioventricular canal defect with cyanosis

Carla Tanamati; Renata Lure Suguimoto; Edmar Atik; Solange Gimenez Copolla; Filomena Regina Galles; Vera Demarchi Aiello; Miguel Lorenzo Barbero-Marcial

Instituto do Coração do Hospital das Clínicas - FMUSP - São Paulo, SP

^{Mailing address}

ABSTRACT

Atrioventricular septal defects account for 4% of congenital cardiac malformations and over 50% of cardiac defects seen in Down syndrome¹. Clinical presentation is marked by congestive heart failure early in infancy. Cyanosis is rarely found in infants and suggests irreversible pulmonary hypertension or associated cardiac defects as tetralogy of Fallot, double outlet right ventricle², Ebstein anomaly³, persistent left superior vena cava draining in the left atrium (Barbero Marcial, personal communication). Children with Down's syndrome is particularly difficult to assess because they often suffer from upper airways obstruction⁴, which may contribute to the increased pulmonary vascular resistance determined at cardiac catheterization. This association of factors becomes a challenge for operability and, we will report one such case.

Key words: Complete atrioventricular septal defect, cyanosis, surgical repair.

Moderate cyanosis (room air oxygen saturation 75%) was presented in a 7-month-old-girl with Down syndrome and total atrioventricular septal defect (AVSD). Despite cyanosis, she still presented some signs of pulmonary overflow as failure to thrive, dyspnea, hepatomegaly, and a left sternal border systolic murmur. Cardiac catheterization showed Qp/Qs = 1,67 and pulmonary vascular resistance of 6,5 U/m².

Complete repair was made with two-patch technique and a small persistent foramen ovale (PFO) was maintained opened. After cardiopulmonary bypass (CPB) the O₂ sat was 80% (FiO₂ 100%, NO 20 ppm). Open lung biopsy was made in the third postoperative day (POD) when the thorax was closed and revealed Heath-Edwards grade III of pulmonary hypertension.

Nitric oxide was maintained until 6^th POD and calcium channel blocker was introduced with improved O₂ saturation. After a long postoperative period marked by congestive heart failure and infection, she was discharged without cyanosis, in functional class II (NYHA).

CASE REPORT

The patient was a 7 month-old-girl with Down syndrome and a history of cardiac murmur since birth, tachypnea and failure to thrive. She was previously hospitalized for a bronchopneumonia, when cyanosis was noted (O₂ sat 80%-85%). Echocardiogram showed total AVSD with a large ventricular septal defect (VSD), common AV valve with moderate regurgitation and an ostium primum (OP) septal defect. Systolic pulmonary artery pressure was estimated by echo in 53mmHg.

On physical examination, there was a moderate cyanosis (O₂ sat 70%-80%), a loud systolic murmur in the left sternum border and hepatomegaly.

Electrocardiogram revealed synus rhythm with signs of right ventricular overload. The chest X-ray showed moderate cardiomegaly and increased pulmonary vascularity. Pulmonary wedge angiogram was normal (Fig 1), pulmonary vascular resistance was 6,5 U/m², with a Qp/Qs 1,67(FiO₂= 100%).

Complete surgical repair was made using 20ºC hypothermic cardiopulmonary bypass. The large and typical VSD was closed with bovine pericardium. AV valve was divided without any residual regurgitation, and ostium primum ASD was closed with autologous pericardium. A small PFO (4mm) was maintained due to the high pulmonary artery pressure. After cardiopulmonary bypass (CPB), TEE showed any valve regurgitation, VSD and ostium primum ASD closed, and a small right-to-left shunt through the PFO. In sinus rhythm, the O2 sat was 80% (FiO2 100%; NO 20ppm). The sternum was maintained open and a PA catheter was inserted through the right ventricle.

The sternum was closed on the 3^rd PO, and a left pulmonary biopsy was made due to persistent high PA pressure (systemic level) with pulmonary hypertension crisis and hypoxemia. The pulmonary biopsy showed grade III Heath-Edwards classification (Fig 2).

Nitric oxide was maintained until 6^th PO and calcium channel blocker (nifedipine) was introduced with improve of O2 sat, 96%.

She presented postoperative bronchopneumonia treated with cefepime and vancomycin, and uremia, and ascites responsive to high doses of diuretics.

After two previous unsuccessful attempts, she was finally extubated on the 20^th POD. Vasoactive drugs were suspended on the 19^th POD, and she was discharged from Pediatric ICU 27^th POD.

In the 20^th POD, after fever episodes, hemoculture and catheter tip cultures were positive for candida albicans, and amphotericin B was maintained for 21 days.

She was discharged from hospital 48 days after operation without dyspnea or cyanosis, or failure to thrive. She was using nifedipine, furosemide, and L-tyroxin.

DISCUSSION

Preoperative assessment of the hypertensive pulmonary circulation and operabilility of these cases are frequently difficult⁵. The clinical history is important, cardiac failure may appear to improve as pulmonary vascular resistance increases. The chest radiography is plethoric when the pulmonary vascular resistance is low to permit a high blood flow,and the development of severe obstructive disease leads to peripheral pruning and hypertranslucent appearance in association with dilation of the hilar and proximal vessels. Cardiac catheterization is used to study the pulmonary wedge angiogram and to measure the pulmonary vascular resistance.

Cyanosis and/or a pulse oximeter reading of < 92% was encountered in 31% of 77 neonates with Down syndrome⁶, and was associated with other cardiac defects as tetralogy of Fallot (11%) and tetralogy of Fallot and AVSD (2%). The presence of moderate cyanosis (O₂ sat 80%-85%) in patients with complete AVSD is suggestive of pulmonary vascular obstructive disease and operability should be extensively studied preoperatively. Cardiac catheterization with pulmonary wedge angiogram, Qp/Qs and pulmonary vascular resistance calculation with and without pulmonary vasodilators (O₂ ,NO, prostaglandin) is mandatory. This patient still had symptoms of cardiac failure (tachypnea,failure to thrieve,hepatomegaly) and cardiac catheterization showed normal pulmonary wedge angiogram, Qp/Qs = 1,67, and PVR = 6,5 U/m². Despite elevated pulmonary vascular resistance and cyanosis, the presence of signs of congestive heart failure encourage the surgical repair.

Complete repair was made maintaining a small PFO (4mm) opened to decompress the right heart. Nitric oxide (10 ppm), 100% FiO_2, and milrinone was administered since coming off bypass and were substituted by calcium channel blocker to control postoperative pulmonary hypertensive crisis (Table1). Open lung biopsy was made in the third PO when the sternum was closed, but in cases with suspect of pulmonary vascular disease biopsy should be indicated as a criteria of operability^7,8,9. In this case, despite cyanosis there was a favorable postoperative clinical evolution. Regression of pulmonary hypertension might be attributed to potential growth of pulmonary vascular bed¹⁰, however long-term follow-up and non-invasive monitoring of pulmonary artery pressure is mandatory.

Similar congenital heart defects like VSD in patients with higher than 6U/m2 pulmonary vascular resistance index should also be considered for surgical repair, when there are still signs of left-to-right shunt. In the literature, long-term follow-up after VSD closure in patients with a previous pulmonary vascular resistance greater than 6U/m2 showed good outcome¹¹ in 31 (79%) with significant reduction of pulmonary artery pressures. A wider overview of these patients concerning clinical and laboratory data prior to surgical intervention can guide to the most appropriate management.

Potential Conflict of Interest

No potential conflict of interest relevant to this article was reported.

REFERENCES

Received on 03/22/05

Accepted on 08/22/05

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• 9. Guimarães JI, Lopes AA, Martins RF, et al. Guideline for diagnosis, evaluation and therapeutic of pulmonar hypertension. Arq Bras Cardiol. 2003; 81(Suppl 8): 1-10.
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Publication Dates

• Publication in this collection
  16 Oct 2006
• Date of issue
  Sept 2006

History

• Accepted
  22 Aug 2005
• Received
  22 Mar 2005