INTERVENTIONAL PEDIATRIC CARDIOLOGY

False Aneurysm and Mediastinal Hematoma: Complications of Simultaneous Transcatheter Therapy for Coarctation of the Aorta and Pa

Chi Di Liang, MD, *Sheung Fat Ko, MD, Mao Meng Tiao, MD
Chi Di Liang, MD, *Sheung Fat Ko, MD, Mao Meng Tiao, MD
Coarctation of the aorta (CoA) is frequently associated with patent ductus arteriosus (PDA). Balloon angioplasty of CoA and coil treatment of PDA has been reported as an effective alternative to surgical therapy. However, simultaneous interventional catheterization therapy for CoA and PDA is not encouraged.1,2 We report the experience of a 4-month-old infant, with intractable congestive heart failure caused by CoA and PDA, who underwent both balloon angioplasty and coil occlusion during a single procedure. After balloon angioplasty, his heart failure dramatically resolved. An asymptomatic mediastinal hematoma was noted incidentally by echocardiography on the next day. During the follow-up period, the echocardiography revealed that the mass had no progressive enlargement; and it resolved 10 weeks later. Case Report. A 4-month-old male infant was admitted with lethargy, cold sweating, poor appetite and progressive dyspnea for 1 month. His past history revealed a diagnosis of CoA, PDA, atrial septal defect, and multiple muscular ventricular septal defects after birth. The pressure gradient across the CoA was 30 mmHg measured on Doppler scan. He was treated with oral digoxin and furosemide at that time. Physical examination revealed diminished femoral pulses and evidence of heart failure. The chest radiograph revealed cardiomegaly and pulmonary congestion. The electrocardiogram showed left ventricular hypertrophy with strain. Follow-up echo-Doppler study revealed no obvious anatomical change compared with previous examination. The left to right shunts through both atrial and ventricular septal defects were restrictive, but a peak instantaneous Doppler gradient increased to 45 mmHg across the CoA. Transcatheter treatment of CoA and PDA was suggested. The interventional catheterization was performed after written informed consent was obtained from his parents. Aortography demonstrated a discrete stenosis in the isthmus of the aorta and a small ductus arteriosus (Figure 1A). The diameter of the coarctation segment was 2.5 mm and the aortic isthmus was 7 mm. The balloon angioplasty technique used was similar to that described previously.3,4 The coarctation segment was dilated with a 6 mm x 20 mm balloon catheter (Schneider, Glen Falls, New York). The balloon was inflated 3 times with 6, 8 and 10 atmospheres (atm), respectively. After dilation, a Berman angiocatheter was advanced from the descending aorta to the ascending aorta for aortography and pressure record. A 6 mmHg peak gradient across the aortic isthmus was noted and the coarctation segment was increased to 5 mm in diameter (Figure 1B). In addition, the systolic pulmonary pressure decreased from 60 mmHg to 35 mmHg without change of ascending aorta pressure. There was a small PDA with a diameter of 1.7 mm at the narrowest point. The PDA closure technique used was similar to our previously described technique.5 First, we used a 0.025´´ Terumo soft guidewire (Terumo Medical Corporation, Somerset, New Jersey) retrograde through the ductus into the main pulmonary artery. A 4 Fr right coronary catheter was then advanced into the main pulmonary artery over the guidewire. A 3-mm diameter, 5-cm long, 0.038´´ Gianturco coil was delivered using the retrograde technique in the ductus arteriosus. Repeat aortography by Berman angiocatheter revealed no residual ductus arteriosus, no aortic aneurysm, and no extravasations of contrast 15 minutes after coil occlusion (Figure 1C). Pressure measurements confirmed no proximal left pulmonary artery obstruction and no change in the aortic gradient. The net left to right shunt before and after closure of the PDA was 2.1 and 1.7, respectively. After balloon angioplasty, the patient’s heart failure dramatically improved. However, echocardiography revealed a mediastinal mass superior to the main pulmonary artery on the next day (Figure 2A). The mass compressed the pulmonary artery with a maximal velocity of 4 m/second, estimating instantaneous gradients of 64 mmHg between the main and left pulmonary artery. The mass was a solid component, neither identifying blood flow within it nor communicating with the aorta. Chest computed tomography (CT) showed a coil within the ductus proper. A small false aneurysm associated with mediastinal hematoma (21 x 16 mm) adjacent to the aortic arch and compression on the pulmonary artery was noted; the pulmonary arteries were patent. There was no active leakage of contrast media from the aorta. Since his heart failure consistently improved, and his hemoglobin, platelet count, prothrombin time, and partial thrombin time were all within normal limits, we decided to proceed with a supportive treatment and evaluate his condition weekly by echocardiography. In 1 week, echocardiography revealed that the hematoma had no progressive enlargement, and the pressure gradient of the pulmonary artery had no obvious change. In 1 month, the size of the hematoma had constantly decreased. Follow-up echocardiography and CT 10 weeks later revealed total resolution of the hematoma (Figure 2B). The maximal velocity across the pulmonary artery and the descending aorta was 1.2 m/second and 2 m/second, respectively. The patient was last evaluated at 16 months of age. The arm-leg pressure gradient was less than 5 mmHg. An echocardiogram demonstrated no residual PDA, no left pulmonary artery obstruction and no aneurysm at the dilation site. Discussion. CoA and PDA are commonly associated defects at birth. The hemodynamic consequences of this association are pulmonary and systemic hypertension, which can lead to heart failure. This association differs from a discrete coarctation in older patients; CoA in infancy is often part of a more complex spectrum of heart disease. Traditionally, both malformations can be eliminated with one surgical procedure. Recently, in selected patients, newer methods of percutaneous transcatheter treatment of both malformations have been successfully performed.1,2,6 Because aortic angioplasty causes disruption of the intima and a portion of the media, some authors believe that closure of a small PDA should be accomplished at a separate catheterization.1,2 However, Ing et al. reported a successful case by using both techniques during a single procedure in a 3.5-year-old patient.6 We tried to treat our patient in a single session following Ing’s recommendation; however, a mediastinal hematoma occurred after the procedure. Although the outcome of this patient was good, there are some points that shall be highlighted. First, intimal tear usually occurs after balloon angioplasty; further manipulation at the dilated site by guidewire or catheter should be avoided. Finley et al. described the possibility of traumatic rupture of the aorta at the site of balloon angioplasty after manipulating catheters or wires to evaluate the post-angioplasty gradient.7 In this case, we postulated that the small aortic intima might be induced by a soft-tip guidewire or by Berman catheter, and the hematoma was formed by aortic tear that fortunately spontaneously sealed off. Passing a guidewire through the PDA into the pulmonary artery (by retrograde method) before balloon angioplasty or using the antegrade method to place the coil in the PDA after balloon angioplasty may prevent further injury of the intimal tear. Therefore, our experience emphasizes that catheter or guidewire manipulation should be avoided in a freshly dilated artery, because regardless of careful manipulation, one is still crossing a freshly dilated area that can potentially end in rupture of the aorta and demise of the patient. Second, the CoA should be fully dilated before coil occlusion. If the pressure gradient is not adequately relieved, the coil may impinge on the aortic wall and further increase the stenosis. Third, special care with echocardiography evaluation is mandatory after interventional catheterization because some cases of unexplained sudden death are reported after uncomplicated dilatation.3,8 Mediastinal hematoma associated with trauma is thought to be a common entity.9,10 However, it is rare in non-traumatic patients.11,12 Echocardiography, CT, aortography and magnetic resonance imaging are good modalities to evaluate the conditions. MRI is an excellent modality to evaluate mediastinal masses from a vascular etiology; however, in this case the coil was lodged in the PDA, which generated a prominent artifact and thus precluded its usage. Aortography can reliably demonstrate aortic laceration, aneurysm or pseudoaneurysm; however, it is relatively invasive and not without risk. We chose echocardiography and CT to evaluate this patient. CT with contrast enhancement is a useful imaging modality typically employed for evaluation of mediastinal lesions or vascular pathologies. In this case, based on the patient’s clinical features, the echocardiography and CT findings (i.e., mediastinal hematoma was homogenous and no active leakage of contrast medium was noted), surgery was not absolutely necessary. If the hematoma had progressively enlarged or presented the signs of cardio-respiratory instability, surgical intervention would have been performed without delay. In summary, we report the experience of a young infant with CoA and PDA who underwent both balloon angioplasty and coil occlusion during a single procedure. This procedure is by no means without risk and potential complications should be considered.
References
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