Abstract
Balloon atrial septostomy is ordinarily a safe palliative procedure for cyanotic congenital heart disease; however, if echocardiographic guidance is unavailable and fluoroscopy is used, distortions in the cardiac anatomy can invalidate the usual landmarks. Herein, we report iatrogenic mitral papillary muscle rupture during balloon atrial septostomy in a 4-day-old male neonate with total anomalous connection of the pulmonary veins. The anomalous connection and severe mitral regurgitation were emergently corrected, and the patient grew and developed normally. At age 24 years, he had only mild residual mitral regurgitation and was in New York Heart Association functional class I.
In addition to describing the surgical treatment and positive late outcome of a rare complication, we highlight the importance of accurately evaluating balloon catheter location during atrial septostomy, especially in patients with a small left atrium.
Key words: Balloon dilation/adverse effects; cardiac surgical procedures; echocardiography; heart rupture/complications; infant, newborn; mitral valve/injuries; palliative care; papillary muscles/pathology; pulmonary veins/abnormalities; treatment outcome
Rupture of the mitral subvalvular apparatus in neonates is an extremely rare event. In the only previous report of which we are aware, a 21-day-old neonate underwent successful repair of a congenital chordae tendineae rupture.1 Herein, we describe iatrogenic mitral valve papillary muscle rupture during balloon atrial septostomy in a 4-day-old neonate, the potential risks of the septostomy procedure, and the late outcome of the surgical treatment.
Case Report
A full-term male infant was born in May 1987. His Apgar scores were 6 and 7. Profound cyanosis with increasing respiratory distress prompted the use of mechanical ventilation. Because the neonate remained hypoxemic, he was diagnosed with persistent fetal circulation. He was transferred urgently to an out-of-state hospital for possible extracorporeal membrane oxygenation. Upon his arrival, congenital heart disease was suspected, and a supracardiac-type total anomalous pulmonary venous connection (TAPVC) was confirmed by means of echocardiography and cardiac catheterization. He was transported to a tertiary children's hospital in his home state for continued management. There, echocardiography suggested a restrictive atrial septal communication.
Balloon atrial septostomy was attempted on the infant's 4th day of life. A 5F Miller balloon septostomy catheter (Edwards Lifesciences LLC; Irvine, Calif) was inserted into the right femoral vein and advanced across a small patent foramen ovale (PFO) into the left atrium, under fluoroscopic guidance. The inflated balloon could not be withdrawn from the restrictive PFO, so it was deflated and the catheter was removed. Another catheter with a 4-cc balloon was advanced to the level of the PFO, but the apparatus would not cross into the left atrium. Finally, a 6F, 3-cc balloon was advanced across the PFO into the left atrium, and, inadvertently, across the mitral valve into the left ventricular apex. When the inflated balloon was forcefully withdrawn, it ruptured both the mitral valve and the atrial septum (Fig. 1A). An echocardiogram confirmed avulsion of the anterolateral papillary muscle of the mitral valve. Severe mitral regurgitation resulted. The chordae tendineae were spared injury.
Fig. 1 Artist's drawings. A) In 1987, the catheter was most likely passed through the mitral valve, behind the chordae tendineae, and deeply into the left ventricle before the balloon was inflated and withdrawn. B) The anterolateral papillary muscle of the mitral valve was completely ruptured into 2 segments; the chordae tendineae were spared injury. C) The anterolateral papillary muscle was reimplanted with the use of 7-0 polypropylene sutures buttressed by autologous pericardial pledgets.
The neonate developed profound congestive heart failure and was transported to our institution for possible cardiac transplantation; however, he was not a suitable candidate because of his severely decompensated state and, hence, his inability to wait for a donor. He was taken directly to the operating room, where a Dubost-type biatrial transseptal incision2,3 enabled access to the mitral valve in the presence of the small left atrium. A flail anterior leaflet due to the complete rupture of the anterolateral papillary muscle was observed (Fig. 1B). The papillary muscle was reimplanted with the use of 7-0 polypropylene vertical mattress sutures in the anterior and posterior aspects of the ruptured muscle. The sutures were buttressed with autologous pericardial pledgets (Fig. 1C). The TAPVC was corrected, and the atrial septal defect was closed. On postoperative day 19, the infant was returned to the operating room for augmentation of the right pulmonary veins with use of an autologous pericardial patch.
The infant was weaned from ventilator support, and he was discharged from the hospital on postoperative day 57. At that time, echocardiography revealed moderate residual mitral regurgitation, and chest radiographs showed mild-to-moderate cardiomegaly. The symptoms of heart failure were controlled medically. Over time, echocardiograms showed a gradual reduction in the mitral regurgitation. At 10 years of age, the patient had a soft, pansystolic murmur at the left ventricular apex, but chest radiography showed no cardiomegaly. He grew and developed normally, without exercise intolerance or congestive heart failure. A transesophageal echocardiogram in September 2009 showed mild residual mitral regurgitation (Fig. 2). At age 24 years, the patient was well and had recently been married.
Fig. 2 Transesophageal echocardiography (4-chamber view) shows mild mitral regurgitation and mild prolapse of the anterior mitral leaflet.
LA = left atrium; LV = left ventricle; MR = mitral regurgitation; RV = right ventricle
Discussion
Mitral papillary muscle rupture in a neonate is extremely rare. It has been reported during balloon aortic valvuloplasty in an infant with aortic stenosis,4 but not during balloon atrial septostomy. In describing their palliative approach to transposition of the great arteries, Rashkind and Miller envisioned the risk of misplacing the balloon into an incorrect cardiac chamber.5 Echocardiography has improved accurate catheter guidance and avoidance of this sequela.6
Immediate surgical repair is the standard of care for patients with TAPVC. However, in a center where surgery is unavailable, palliative atrial septostomy may stabilize some neonates before surgical intervention.7 Echocardiographic guidance is optimal for catheter placement and balloon deployment. If echocardiography is unavailable, the interventional cardiologist might rely on fluoroscopy, using access to the pulmonary vein and differences in pressure and oxygen saturation between the atria to accurately identify the left atrial position of the catheter tip.8 However, the distorted anatomy in patients with TAPVC invalidates the usual landmarks,7,9 making septostomy, as performed 24 years ago, more challenging technically. Furthermore, a smaller left atrium increases the risk of entering the left ventricle.10 These issues contributed to the malpositioning of the balloon catheter into the neonate's left ventricle, which led to the mitral papillary muscle rupture. An inflated balloon engaged under the mitral valve would tip downward and move forcibly with cardiac contractions, a situation that was unrecognized by the cardiologists when balloon septostomy was attempted in this patient in 1987.
We first saw this patient when he was referred to our institution for heart transplantation. The urgency of the situation prompted an attempt to repair the ruptured papillary muscle and to correct the congenital heart anomaly. Alternatively, a challenging (if not impossible) valve replacement would have been required, leading to years of anticoagulation and the surgical placement of progressively larger valves as the patient grew. Valve repair in this infant led to a satisfactory late outcome. The moderate early residual mitral regurgitation gradually improved during the 24-year follow-up period: at his last evaluation, the patient was in New York Heart Association functional class I.
Acknowledgment
The authors thank Mr. Robert Knabenbauer, medical artist, for drawing Figure 1.
Footnotes
Address for reprints: Leonard L. Bailey, MD, Department of Cardiovascular & Thoracic Surgery, Loma Linda University Medical Center & Children's Hospital, 11175 Campus St., Suite 21120, Loma Linda, CA 92354
E-mail: lbailey@llu.edu
References
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