Age: 22 years
Gender: Female
Occupation: Student
Working diagnosis: Tetralogy of Fallot with pulmonary atresia
HISTORY
This patient presented in early infancy when she was noticed to be cyanosed by a home health visitor. Following investigation, the diagnosis of pulmonary atresia with VSD was made. Palliative surgery, namely bilateral placement of modified BT shunts, was performed in infancy and early childhood to enhance pulmonary blood flow.
This surgery permitted the patient to develop and grow normally such that definitive surgical repair could then be performed. At the age of 6, restoration of continuity between the RV and pulmonary arteries was established with a 17-mm homograft conduit. A further 11-mm homograft conduit was used to augment and attach the left pulmonary artery to the reconstructed outflow tract. The VSD was closed. The operation was uncomplicated, but recovery was slow with a long period in intensive care. Following surgery, the patient had an uneventful childhood.
At age 18, she started her university education and became aware of increasing fatigue and breathlessness with moderate exertion. Over the ensuing years the problem became more noticeable. She returned for follow-up.
Comments: Pulmonary atresia with VSD is a variant of TOF, and is sometimes called complex pulmonary atresia. The pulmonary blood supply is dependent initially on patency of the ductus arteriosus, and later on the presence of aortopulmonary collateral arteries.
The BT shunt, first performed in 1944 by Alfred Blalock and Vivian Thomas, marked the beginning of rapid development in surgery for ACHD. This progress has resulted in a marked improvement in prognosis for patients with congenital heart defects with more than 85% of patients now surviving into adult life.
CURRENT SYMPTOMS
The patient has noticed increasing tiredness and shortness of breath on moderate exertion. She did not complain of palpitations, light-headedness, or chest pains.
NYHA class: II
Comments: Here the symptoms most likely represent conduit failure—either conduit stenosis or regurgitation. Pulmonary valve regurgitation, present in many patients with TOF, has detrimental effects on RV function and exercise capacity and can increase the risk of arrhythmia and sudden death. Most often it is found in patients with prior transannular patch repair of classic TOF. The presence of branch pulmonary artery stenosis in this situation increases the regurgitant load on the RV and is associated with accelerated clinical deterioration.
PHYSICAL EXAMINATION
BP 110/70 mm Hg, HR 74 bpm, oxygen saturation 97%
Height 155 cm, weight 73 kg, BSA 1.77 m 2
Surgical scars: Median sternotomy and bilateral thoracotomy
Neck veins: Not distended
Lungs/chest: Clear to auscultation
Heart: Regular rate and rhythm were present, with the apex beat displaced to the left. There was an RV heave. A 3/6 ejection systolic murmur was heard at the left sternal edge radiating to the back and to the left axilla. Also, a 2/4 early diastolic murmur at the left sternal edge was present.
Abdomen: No abnormalities detected
Extremities: No peripheral edema or cyanosis was seen.
LABORATORY DATA
| Hemoglobin | 13.3 g/dL (11.5–15.0) |
| Hematocrit | 40% (36–46) |
| White cell count | 10.2 × 10 9 /L (4.5–13.5) |
| Platelet count | 257 × 10 9 /L (150–400) |
| Sodium | 140 mmol/L (134–145) |
| Potassium | 3.7 mmol/L (3.5–5.2) |
| Creatinine | 0.63 mg/dL (0.6–1.2) |
| Urea | 3.5 mmol/L (2.5–6.5) |
| PT | 31 sec (26–38) |
| APTT | 10.7 sec (9.9–12.5) |
Comments: Normal blood results.
ELECTROCARDIOGRAM
FINDINGS
Heart rate: 77 bpm
Rhythm: Sinus rhythm
QRS axis: Right-axis deviation (×110°)
QRS duration: 150 msec
RBBB pattern
Comments: QRS duration correlates with RV volume in patients with repaired tetralogy. A QRS duration on the resting ECG of at least 180 msec is a predictor of life-threatening ventricular arrhythmia.
CHEST X-RAY
FINDINGS
Cardiothoracic ratio: 62%
Moderate cardiomegaly, cardiac shape consistent with RV hypertrophy. The inapparent pulmonary trunk fits with the diagnosis of tetralogy. Calcification of the homograft and left pulmonary artery can be seen. There is a surgical clip relating to previous shunt ligation. There is a right aortic arch (boot-shaped heart). The lung fields are clear.
Comments: CXR is useful for identifying the presence of circumferential homograft/conduit calcification. If transcatheter intervention is considered, this finding is encouraging as it indicates the potential for device stability.
FINDINGS
Cardiomegaly with retrosternal filling consistent with RV hypertrophy and/or a retrosternal conduit. Surgical clip relating to previous shunt ligation. The lung fields are clear.
EXERCISE TESTING
| Exercise protocol: | Ramp protocol |
|---|---|
| Peak workload: | 90 Watts |
| Reason for stopping: | Dyspnea and leg pain |
| ECG changes: | RBBB, frequent ectopic beats |
| Rest | Peak | |
|---|---|---|
| Heart rate (bpm): | 74 | 153 |
| Percent of age-predicted max HR: | 77 | |
| O 2 saturation (%): | 97 | 98 |
| Blood pressure (mm Hg): | 110/70 | 155/80 |
| Peak V o 2 (mL/kg/min): | 19 | |
| Percent predicted (%): | 62 | |
| Ve/V co 2 : | 32 | |
| Metabolic equivalents: | 6.9 | |
Comments: Poor cardiopulmonary exercise capacity identifies ACHD patients at risk of hospitalization or death. Cardiopulmonary exercise capacity can improve following restoration of pulmonary valvar competency.
ECHOCARDIOGRAM
FINDINGS
A moderately dilated, hypertrophied RV was seen with mildly impaired function. The LV was normal except for paradoxical septal motion. There was trivial tricuspid regurgitation, with a peak regurgitant velocity of 3.8 m/sec. There was mild dilation of the RA. The IVC collapsed normally with respiration.
Comments: There was evidence of RV volume overload, although the central venous pressure was normal.
FINDINGS
The calcified homograft was seen with degeneration of the valve leaflets. The peak gradient was 45 mm Hg, with a mean gradient of 21 mm Hg.
There was moderate pulmonary regurgitation lasting 71% of the diastolic duration. The pressure half-time was 122 msec. Diastolic flow reversal was present in the branch pulmonary arteries, and there was a proximal left pulmonary artery stenosis.
Comments: The pressure half-time was less than 100 msec and duration of pulmonary regurgitation was less than 77% diastolic duration on continuous-wave Doppler echocardiography correlated with severe pulmonary regurgitation as quantified by MRI. However, these measurements should be interpreted with caution, as they can be influenced by RV end-diastolic dysfunction (restriction).
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