Case 3 / 2018 - Corrected Transposition of the Great Arteries with Natural Progression to Severe Biventricular Dysfunction and No Associated Defects in a 51-Year Old Man

Computed tomography coronary angiography: Left-dominant coronary circulation. The right ventricle was perfused by an arterial branch originating at the posterior sinus of Valsalva and bifurcating into posterior circumflex artery, ventricular artery and marginal artery. It was also perfused by the anterior ventricular artery, a coronary artery branch that arises from the anterior Valsalva sinus. Left ventricle was perfused at right by the artery that arises from anterior Valsalva sinus as a thin branch and travels towards the anterior surface (Figure 2).


Clinical data
Dyspnea on exertion for two years, progressing to low cardiac output and syncope lately, treated with dobutamine and usual drugs for congestive heart disease (currently using furosemide 40 mg, spironolactone 25 mg and losartan 12.5 mg).
Precordium: Apex beat was not palpable, without systolic impulses. Low heart sounds, and low intensity heart murmur heard in the left lower sternal border. Liver was not palpable and lungs were clear.
Chest radiography:Enlarged heart due to round-shaped left ventricular arch and double-density left atrium with elevation of left bronchus. Congestion of pulmonary vessels, enlarged descending aorta, dilation of mid-aortic arch. Cardiothoracic index 0.61 ( Figure 1).

Computed tomography coronary angiography:
Left-dominant coronary circulation. The right ventricle was perfused by an arterial branch originating at the posterior sinus of Valsalva and bifurcating into posterior circumflex artery, ventricular artery and marginal artery. It was also perfused by the anterior ventricular artery, a coronary artery branch that arises from the anterior Valsalva sinus. Left ventricle was perfused at right by the artery that arises from anterior Valsalva sinus as a thin branch and travels towards the anterior surface ( Figure 2).
Clinical diagnosis: Corrected transposition of the great arteries with severe biventricular dysfunction and no associated defects.
Clinical reasoning: There were clinical evidence of corrected transposition of the great arteries, particularly a late ventricular dysfunction detected few years ago due to tiredness. This is corroborated by electrocardiographic signs, especially the orientation of ventricular repolarization characterized by orientation of the T-wave to the right. The diagnosis was well established by echocardiography and magnetic resonance imaging. The late ventricular dysfunction was probably caused by relative coronary insufficiency caused by systemic right ventricular hypertrophy, despite good irrigation seen in computed tomography coronary angiography.

Differential diagnosis:
In adult patients, all other causes of ventricular dysfunction may be considered, including ischemic cardiomyopathy and dilated cardiomyopathy of other causes.

Management:
Heart transplantation was indicated due to significant biventricular dysfunction.
Comments: Corrected transposition of the great arteries with no associated defects has an incidence of 10-15%. Both patients with natural progression of the disease and those who undergo surgical techniques for functional correction progress to different degrees of systemic right ventricular dysfunction in adult age. 1,2 It becomes even worse with advanced age and occurs in 50-80% of these cases. From eight more advanced age cases reported in the literature, five of them had congestive heart failure. 3 The congestive syndrome may be explained by relative coronary insufficiency related to the hypertrophied systemic right ventricle. In this regard, the decreased coronary flow has been well documented in the  literature and recognized as a consequence of right ventricular dysfunction, and the main long-term sequela of this condition. Decreased coronary flow after vasodilation with adenosine, resulting in altered vasoreactivity and possible microcirculation was previously reported, 4 which may explain the ventricular dysfunction. Therefore, the best option for these patients may be atrial and arterial anatomic repair by double switch operation in some stage of the disease. 1,2