J Thorac Cardiovasc Surg 2007;133:1371-1373
© 2007 The American Association for Thoracic Surgery
Reversal of increased pulmonary arterial pressure associated with systemic venous collaterals after tonsillectomy in a Fontan candidate after the Glenn procedure: Impact of obstructive sleep apnea on Fontan circulation
Hirofumi Sawada, MDa,
Yoshihide Mitani, MD, PhDa,*,
Hiroyuki Ohashi, MDa,
Hidetoshi Hayakawa, MD, PhDa,
Yukiko Ikeyama, MDa,
Shin Takabayashi, MD, PhDb,
Hideto Shimpo, MD, PhDb,
Kazuo Maruyama, MD, PhDc,
Yoshihiro Komada, MD, PhDa
a Department of Pediatrics, Mie University Graduate School of Medicine, Tsu, Mie, Japan
b Departments of Thoracic and Cardiovascular Surgery, Mie University Graduate School of Medicine, Tsu, Mie, Japan
c Department of Anesthesiology, Mie University Graduate School of Medicine, Tsu, Mie, Japan.
Received for publication December 27, 2006; accepted for publication January 2, 2007.
* Address for reprints: Yoshihide Mitani, MD, PhD, Department of Pediatrics, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu city, Mie Pref, 514-8507, Japan. (Email: ymitani{at}clin.medic.mie-u.ac.jp).
An increase in pulmonary artery (PA) pressure, associated with the development of systemic venous collaterals, is one of the greatest risks for candidates for the Fontan procedure after the Glenn procedure.1,2
Simple coil embolization for such collaterals may not be sufficient, inducing other collaterals accompanied by persistent high PA pressure with poor outcomes. Mild pulmonary hypertension is a common complication associated with obstructive sleep apnea (OSA).3 However, the effects of OSA on pulmonary circulation in Fontan candidates are unknown. We report a patient with a successful Fontan completion in whom high PA pressure associated with venous collaterals after the Glenn procedure was reversed after a tonsillectomy for OSA after coil embolization.
Clinical Summary
A 3-year-old boy with pulmonary atresia with an intact ventricular septum presented with progressive cyanosis. The boy had undergone a right modified Blalock–Taussig shunting procedure in the neonatal period and a bidirectional cavopulmonary anastomosis at the age of 6 months. His parents had noticed his dysphagia and nocturnal apnea accompanied by snoring since he was 1 year and 6 months old. Cyanosis and desaturation increased at the age of 2 to 3 years (Figure 1). The patient was admitted to our hospital for the cardiac catheterization. The awake arterial oxygen saturation was 75%. Contrast injection revealed systemic venous collaterals from the innominate vein to the left renal vein (Figure 2, A). The mean pressures in the PA and transpulmonary gradient, measured under controlled mechanical ventilation, were 15 mm Hg and 11 mm Hg, respectively. At the age of 3 years and 6 months, transcatheter coil embolization for systemic venous collaterals was performed in this patient, and beraprost (an orally active prostacyclin analogue) was started. Cardiac catheterization 6 months after coil embolization revealed that the venous collaterals were completely occluded (Figure 2, B) and the systemic saturation was 89%. However, the mean PA pressure was as high as 17 mm Hg. Symptoms of OSA persisted, and third-degree hypertrophy of the tonsils was found. Because we speculated that increased PA pressure might be related to OSA, the patient underwent tonsillectomy at the age of 4 years and 2 months, and dysphagia and snoring ceased. Cardiac catheterization, 9 months after tonsillectomy, revealed that the venous collaterals remained occluded, and that the mean pressures of PA and transpulmonary gradient were decreased to 11 mm Hg and 4 mm Hg, respectively. At the age of 4 years and 11 months, the patient successfully underwent the Fontan procedure. He was extubated in the operation room, and the postoperative course was uneventful without using inotropic agents or pulmonary vasodilators. Catheterization 11 months after the Fontan operation revealed that systemic saturation was 95%, without obvious venous collaterals (Figure 2, C). The mean PA pressure was 11 mm Hg. During the 3-year postoperative follow-up, he has been well without recurrence of cyanosis.
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Figure 1. Changes in oxygen saturation levels and pulmonary hemodynamics over time and their association with treatments for cardiovascular disorder and OSA. Rt.m-BT, Right modified Blalock–Taussig; PA, pulmonary artery; LA, left atrium.
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Figure 2. A, Pulmonary angiograms at the age of 3 years and 4 months. Contrast injection in the superior vena cava shows venous collateral drain into the left renal vein. PA index (cross-sectional area of the right and left PAs/body surface area) was 114 mm2/m2. B, Angiography after transcatheter coil embolization for systemic venous collaterals. The collaterals were completely occluded. PA index was 167 mm2/m2. C, Angiography 6 months after Fontan operation. PA index was 162 mm2/m2.
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Discussion
A major finding in this case report is that elevated PA pressure accompanied by systemic venous collaterals was reversed after tonsillectomy in a Fontan candidate after the Glenn procedure. High PA pressure, as demonstrated by cardiac catheterization, was consistent with the appearance of significant venous collaterals. Snoring, a symptom of OSA, preceded progressive cyanosis, which may have coincided with the development of systemic venous collaterals. Furthermore, persistent high PA pressure after coil embolization subsided when snoring ceased after the tonsillectomy. These changes in pulmonary hemodynamic parameters were determined under controlled ventilation. Such improvement in pulmonary parameters was consistently followed by an uneventful postoperative course, with reasonably low PA pressure after the Fontan procedure. Therefore, the sequence of events is consistent with the hypothesis that the increase in PA pressure may have been caused by obstructive tonsillar hypertrophy and was thereby reversed after tonsillectomy in this patient.
Tonsillar hypertrophy is a common cause of OSA in children. Moderate-to-severe OSA is frequently associated with mild pulmonary hypertension,3 which is characterized by mild pulmonary vascular remodeling and endothelial dysfunction, as shown in human and animal studies.4,5 Therefore, it is possible that the magnitude of structural and functional alterations in pulmonary vasculature induced by nocturnal desaturation had significant impacts on the Glenn circulation, and that these changes were reversed after tonsillectomy in this case. Furthermore, it is interesting to speculate that such derangement in pulmonary circulation caused by OSA might have similar effects on hemodynamics in patients even after the Fontan procedure. This unique case implies that alleviation of OSA (ie, tonsillectomy) may be an efficacious treatment option for high-risk candidates for the Fontan procedure with high PA pressure after the Glenn procedure.
References
- Bartmus DA, Driscoll DJ, Offord KP, Humes RA, Mair DD, Schaff HV, et al. The modified Fontan operation in children less than 4 years old. J Am Coll Cardiol 1990;15:429-435.[Abstract]
- McElhinney DB, Reddy VM, Hanley FL, Moore P. Systemic venous collateral channels causing desaturation after bidirectional cavopulmonary anastomosis: evaluation and management. J Am Coll Cardiol 1997;30:817-824.[Abstract]
- Kessler R, Chaouat A, Weitzenblum E, Oswald M, Ehrhart M, Apprill M, et al. Pulmonary hypertension in the obstructive sleep apnoea syndrome: prevalence, causes and therapeutic consequences. Eur Respir J 1996;9:787-794Review.[Abstract]
- Sajkov D, Wang T, Saunders NA, Bune AJ, Mcevoy RD. Continuous positive airway pressure treatment improves pulmonary hemodynamics in patients with obstructive sleep apnea. Am J Respir Crit Care Med 2002;165:152-158.[Abstract/Free Full Text]
- Thomas BJ, Wanstall JC. Alterations in pulmonary vascular function in rats exposed to intermittent hypoxia. Eur J Pharmacol 2003;477:153-161.[Medline]
