Age: 32 years
Gender: Female
Occupation: Radiographer
Working diagnosis: Transposition of the great arteries
HISTORY
The patient was cyanosed at birth and found to have TGA. She underwent reparative surgery at the age of 2 years, with the creation of a Mustard baffle. She subsequently enjoyed a normal childhood, with no physical limitation.
At age 21, her exercise capacity became markedly reduced. She was found to have obstruction of the IVC flow through the atrial baffle, which was treated successfully with balloon dilatation. This recurred 5 years later, and she was treated, again successfully, with balloon dilatation of the obstruction and insertion of a stent. Until recently, she exercised regularly at the gym, running 20 minutes a day and taking boxing classes. She continued taking a diuretic daily.
When she was 32 years old, her exercise capacity again declined. She reported significant ankle swelling if she missed her diuretic. Physical examination found no features of right or left heart failure. At exercise testing she completed 11 minutes of the Bruce protocol with the expected cardiovascular response. Echocardiography showed hypertrophy but good function of the systemic RV, normal valves, and widely patent systemic and pulmonary venous pathways.
She continued to deteriorate despite an increased dose of diuretics and was admitted to the hospital because of progressive dependent edema.
Comments: Atrial redirection surgery was the mainstay of treatment until the mid-1980s at most institutions3, when the arterial switch operation became the treatment of choice for TGA without pulmonary stenosis (see Case 52 ).
One of the complications of atrial redirection is obstruction of the low pressure venous return though the baffles. Often such obstruction can be tolerated for years because of runoff through the azygos system. Therefore, one should not routinely assume that the presence of obstruction is necessarily the cause of symptoms until other factors are excluded.
Deterioration in a Mustard patient should prompt investigation for systemic RV failure, regurgitation of the systemic AV valve (tricuspid valve), heart block, atrial arrhythmia, and obstruction or leak of the atrial baffle.
CURRENT SYMPTOMS
The patient no longer attended the gym and had had to stop work. She was able to walk only 100 yards slowly. She also had abdominal bloating and swelling. She said she felt “exactly the same as when the baffle was obstructed.” Her weight was considerably higher than it had been a year previously.
NYHA class: III
Comments: The history thus far is worrisome for further obstruction of her IVC flow.
PHYSICAL EXAMINATION
BP 115/75 mm Hg, HR 92 bpm, oxygen saturation 98%
Height 160 cm, weight 59.2 kg, BSA 1.62 m 2
Surgical scars: None
Neck veins: JVP was visible 2 cm above the sternal angle with a normal waveform.
Lungs/chest: Chest was clear.
Heart: The pulse was regular. Heart sounds were normal with no added sounds; there was no heave, and peripheral pulses were all normal.
Abdomen: Smooth hepatomegaly (3 cm) and moderate ascites
Extremities: She was warm and well-perfused. Her ankles were free of edema, as were the upper extremities.
Comments: Features of baffle obstruction depend on the location of the obstruction. Obstruction within the SVC pathway usually manifests as upper body venous distension. Inferior baffle obstruction may result in abdominal swelling, hepatosplenomegaly, ascites, and lower limb edema. However, obstruction may go unnoticed if there is significant collateral drainage through the azygos vein.
Although ankle edema was absent due to her treatment, ascites and hepatomegaly were appreciable.
LABORATORY DATA
| Hemoglobin | 9.8 g/dL (11.5–15.0) |
| Hematocrit/PCV | 31% (36–46) |
| MCV | 84 fL (83–99) |
| Platelet count | 305 × 10 9 /L (150–400) |
| Sodium | 137 mmol/L (134–145) |
| Potassium | 3.3 mmol/L (3.5–5.2) |
| Creatinine | 0.75 mg/dL (0.6–1.2) |
| Blood urea nitrogen | 4.3 mmol/L (2.5–6.5) |
| Bilirubin | 39 µmol/L (3–24) |
| Alkaline phosphatase | 1364 U/L (38–126) |
| γ-glutaryl transferase | 381 IU/L (7–33) |
| Alanine transaminase | 37 IU/L (8–40) |
| Albumin | 29 g/L (37–53) |
| C-reactive protein | 135 mg/L (0–10) |
| Iron | 5.3 µ mol/L (12–26) |
| Ferritin | 195 µ g/L (20–186) |
| Transferrin saturation | 8% (20–45) |
| Blood cultures | No growth |
Comments: There is a normocytic anemia, normal renal chemistry, and marked elevation of hepatic enzymes. The pattern is not typical of either an obstructive or a hepatic picture.
ELECTROCARDIOGRAM
FINDINGS
Heart rate: 70 bpm
QRS axis: +135°
QRS duration: 95 msec
Sinus rhythm with low-amplitude P-waves. There is marked right-axis deviation and tall dominant R-waves in the anteroseptal chest leads, with T-wave inversion in V1 and V2, reflecting the mandatory systemic RV hypertrophy.
Comments: Maintenance of sinus rhythm is relatively uncommon in Mustard patients. Sinus rhythm is present in only 40% of patients 20 years after surgery. Common rhythms include junctional rhythm and intra-atrial reentrant tachycardia. The other findings are as expected.
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