Case report

A male patient, aged 29 years, had been treated with diuretics for 8 years because of systemic hypertension. He was asymptomatic until six months before admission to hospital, when he started complaining of effort intolerance and orthopnea. Due to progression of these complaints, and the development of paroxysmal nocturnal dyspnoea and malleolar oedema, the patient attended an emergency department. Physical examination revealed signs of heart failure. His first heart sound was normal, and the second heart sound was loud and split. A “to-and-fro” murmur, heard in both systole and diastole, was present at the upper left sternal border, with radiation to the interscapular region. The radial pulses were normal, but the femoral pulses were weak and delayed. Blood pressure was 161 over 92 millimetres of mercury in the right arm, and 139 over 72 millimetres of mercury in the right leg. The patient was admitted with the diagnosis of heart failure, and treated with a diuretic and vasodilator. Subsequent evaluation included transthoracic and transoesophageal echocardiograms and cardiac catheterization. He was found to have aortic coarctation, with a systolic gradient of 50 millimetres of mercury between the ascending and descending components of the aorta. The ascending aorta was aneurysmally dilated, to 7 centimetres diameter, the aortic valve was bicuspid and severely regurgitant, and the left ventricle was dilated, showing decreased systolic function. Left ventricular dimensions were measured at 61 millimetres at end-diastole, and 49 millimetres at end-systole, giving a shortening fraction of 20 percent, and an ejection fraction of 36 percent. Ten days after admission, the patient had been stabilised clinically, so he was referred to our hospital for corrective surgery.

Catheterization was performed via a surgical arteriotomy using an 11 French sheath. The presence of severe aortic coarctation, with a gradient of 45 millimetres of mercury, was confirmed. It was not possible to pass a guidewire from the descending aorta to the aortic arch due to the severity of the stenosis and the angulation of the aorta at this level. Angiography was performed in the descending aorta distal to the site of coarctation (Fig. 1a). Percutaneous catheterization of the right radial artery was performed with a 5-French sheath. A Benson guidewire was advanced antegradely through the coarctation and snared in the descending aorta with a 25-millimetre Microvena^® snare introduced from the femoral artery. The tip of the guidewire was then pulled to the right femoral artery and out through the femoral sheath, thus establishing a circuit between the right radial and right femoral arteries. A catheter could then be passed retrogradely through the coarctation, permitting an angiogram to be obtained in the proximal aorta (Fig. 1b). The aortic diameters measured above and below the coarctation were 25 and 30 millimetres, respectively. As the coarctation was extremely tight we decided to perform initial balloon dilation with a 10-millimetre diameter, 4-centimetre Blue Max^® balloon, followed by a 16-millimetre, 4-centimetre Maxi LD^® balloon. This was followed by implantation of a Palmaz Schatz^® 5014 stent mounted on a 20-millimetre, 6-centimetre Maxi LD^® balloon, leaving a very mild waist. The final angiogram (Fig. 1c) demonstrated an excellent final result, with no aneurysmal formation or extra vascular leakage of contrast. There was no residual gradient after implantation of the stent. Chest X-rays and transthoracic echocardiogram obtained the following day showed correct position of the stent, and a residual systolic gradient of 5 millimetres of mercury.

Figure 1. Angiograms taken (a) in the descending aorta, distal to the coarctation, (b) in the aortic arch, proximal to the coarctation, and (c) after implantation of the stent.

Four days after catheterization, the patient underwent a Bentall operation, with insertion of an aortic conduit containing a St. Jude 23 prosthetic valve, with no complications. He was discharged on the seventh post-operative day.

At six months follow-up, the patient is doing well with a single anti-hypertensive drug and no evidence of recoarctation or aortic regurgitation. Left ventricular dimensions were reduced and systolic func- tion improved, end-diastole dimension now being 48 millimetres, and end-systole dimension 36 millimetres, giving a shortening fraction of 25 percent, and an ejection fraction of 49 percent. A computerized tomographic scan demonstrated absence of recoarctation or aneurysms (Fig. 2).

Figure 2. Computerized tomography scan showing the site of the stent in the descending aorta, with no signs of recoarctation or aneurysmal formation.

Discussion

Our patient required correction of severe native aortic coarctation and replacement of the aortic valve because of severe aortic regurgitation. He had left ventricular dilation, with systolic dysfunction. The main issue was the therapeutic strategy. Should both lesions be corrected surgically or should balloon dilation and implantation of a stent be considered for repair of the coarctation? And which lesion should be approached first?

Surgery could be one-staged, with one or two surgical incisions, or two-staged. It would have been possible to replace the aortic valve and repair the coarctation by insertion of a graft using a single median sternotomy. This option, however, would be associated with a high surgical risk, haemodynamic instability and the necessity of aggressive peri-operative management.³ A one-staged surgical strategy using two incisions, including a median sternotomy for replacement of the aortic valve, and a left lateral thoracotomy for repair of the coarctation, was also an option. Alternatively, a two-staged correction could be used, dealing with the two lesions several days apart.

Whichever the surgical option, another decision had to be made: which lesion should be approached first? Replacing the aortic valve first could carry significant complications due to the presence of coarctation. Repairing the coarctation first could cause problems related to the depressed left ventricular function and aortic regurgitation.

Good results have been described with a two-staged surgical approach, starting with the correction of the intracardiac lesion, followed by coarctation repair two to three months later.¹ This approach avoids the acute changes in coronary flow related to sudden systemic vascular resistance reduction that may occur when the coarctation is repaired first, which may lead to haemodynamic instability and left ventricular failure in the post-operative period.⁴ This strategy may have disadvantages associated with difficulties in weaning from cardiopulmonary bypass with a significantly increased afterload and possible post-operative renal hypoperfusion due to the obstruction caused by the coarctation.

When left ventricular systolic function is depressed, as was the case in our patient, starting by reducing the afterload of the impaired left ventricle seems beneficial.⁵ According to some studies, surgical mortality for repair of aortic coarctation seems to rise gradually with age, reaching up to 4.5 percent in patients over 30 years of age.⁶ Paraplegia is the most serious complication of surgical repair of aortic coarctation, and is related to prolonged clamping of the aorta and injury to the arteries supplying the spinal cord. It occurs in approximately 0.5 to 1 percent of cases. Other complications include paradoxical hypertension, post-coarctectomy syndrome related to visceral reperfusion, injury to the phrenic and recurrent laryngeal nerves, pleural effusion, and complications related to thoracotomy. Recoarctation and aneurysmal formation are uncommon but important late complications.⁶

With balloon dilation and the development of endovascular stents, percutaneous treatment of coarctation became a realistic alternative option to surgery. In children, the use of stents is limited by the size of currently available delivery systems, and by the intrinsic necessity of redilation with somatic growth, but in older children, adolescents, and adults, these are less relevant.^{2, 7}

To avoid potential problems associated with one-stage repair, Magee et al.⁸ have advocated a two-stage approach, implanting a stent to relieve the coarctation, followed within two weeks by replacement of the aortic valve. We chose this option for our patient, and achieved an excellent final result. In summary, therefore, patients with coarctation of the aorta and aortic valvar regurgitation require specific treatment. Special attention must be given to left ventricular dysfunction, and the ability to tolerate acute hemodynamic changes.

Acknowledgements

We thank Professor Maymone Martins for reviewing the manuscript, Dr Ana Oliveira for the anaesthetic care, and Dr Manuel Moradas Ferreira and Dr José Ferreira Santos for referring the patient for catheter intervention.