Usefulness of percutaneous closure of patent foramen ovale for hypoxia Alyssa G. Munkres, MPH, Timothy N. Ball, MD, Themistokles Chamogeorgakis, MD, Kenneth A. Ausloos, MD, Shelley A. Hall, MD, and James W. Choi, MD
We report a patient with hypoxia secondary to a right-to-left shunt through a patent foramen ovale, following aortic root, valve, and arch replacement due to an aortic dissection in the setting of the Marfan syndrome. Following the operation, he failed extubation twice due to hypoxia. An extensive workup revealed a right-to-left shunt previously not seen. The patent foramen ovale was closed using a percutaneous closure device. Following closure, our patient was extubated without difficulty and has done well postoperatively.
A
pproximately 25% of the general population is estimated to have a patent foramen ovale (PFO). These small atrial septal defects, present from birth, are usually asymptomatic and found incidentally by echocardiogram or at autopsy (1). We describe the benefit of closure of a PFO for postoperative hypoxia. CASE DESCRIPTION A 23-year-old Hispanic man with the Marfan syndrome presented with acute chest pain that radiated to his back. The diagnosis of a dilated aortic root and a type B aortic dissection was made quickly by computed tomography scan with contrast. He underwent surgical repair using a two-staged “elephant trunk” procedure. The initial stage of the procedure consists of an aortic valve, root, and arch replacement, including leaving an elephant trunk portion of the graft that hangs down into the descending aorta. Finally the descending thoracic aorta is wrapped at that level of the diaphragm. The second stage of the procedure uses a stent graft, via an endovascular approach, to connect the elephant trunk with the wrapped portion of the aorta. Following the first stage, his postoperative course was complicated by recurrent hypoxia. He underwent two attempted extubations on postoperative days 1 and 7, but the hypoxia persisted. A PFO with a significant right-to-left shunt was found on transesophageal echocardiogram with bubble study (Figure 1). On postoperative day 9, a percutaneous closure procedure was performed via the right femoral vein. A #25 Amplatzer Cribriform Septal Occluder (AGA Medical Corp., Plymouth, MN) was deployed in the PFO, and placement was confirmed with intracardiac echocardiography and fluoroscopy (Figure 2). A negative echocardiographic bubble study at the conclusion of
204
Figure 1. Transesophageal echocardiogram with bubble study, showing rightto-left shunt through a patent foramen ovale. RA indicates right atrium, LA, left atrium; PFO, patent foramen ovale.
the procedure confirmed resolution of the right-to-left shunt. On day 10, extubation was successful and normal oxygen saturation was maintained. The patient was discharged from the hospital on postoperative day 22. Five weeks later, he underwent stage 2 of the “elephant trunk” procedure without postoperative respiratory complications. He continues to do well 5 months following the second stage of the procedure. DISCUSSION Despite the severity of potential consequences of a PFO, hypothesized benefits of closing PFOs, specifically for migraine headaches and strokes, have not resulted in clinical benefit over standard medical management. Three large randomized controlled trials, RESPECT (2), CLOSURE I (3), and PC Trial (4), failed to show a benefit of PFO closure over medical management for the prevention of recurrent paradoxical embolism. The RESPECT trial did, however, demonstrate increased safety and From the Division of Cardiology, Department of Internal Medicine, Baylor Hamilton Heart and Vascular Hospital and Baylor University Medical Center at Dallas. Corresponding author: James W. Choi, MD, Cardiology Consultants of Texas, Baylor Heart and Vascular Hospital, 621 N. Hall Street, Suite 400, Dallas, TX 75226 (e-mail: [email protected]). Proc (Bayl Univ Med Cent) 2015;28(2):204–206
Figure 2. A cineflourographic image of the #25 Amplatzer Cribriform Septal Occluder (AGA Medical Corp, Plymouth, MN) following deployment.
efficacy of the Amplatzer PFO Occluder device over the previously used STARFlex Septal Closure System (2, 4). While there is ample evidence through observational studies for the efficacy of PFO closure in prevention of recurrent embolic strokes, no studies have been able to provide evidence for significant benefit Table 1. Previously published cases discussing closure of patent foramen ovale for hypoxia Clinical setting
First author (reference)
PostDlabal (7) pneumonectomy Vacek (8)
Closure method Surgical
Hypoxia lessened +
Surgical
+
Hazard (9)
Percutaneous—balloon
+*
Berry (10)
Surgical
+
Landzberg (11)
Percutaneous—clamshell
+
Godart (12)
Percutaneous—button
+
Alfaifi (13)
Surgical
+
Mall (14)
Surgical
+
Pai (15)
Percutaneous—Amplatzer
+
Thoracic aortic maneurysm
Chopard (16)
Percutaneous—Amplatzer
+
Townsend (17)
Surgical
+
Left ventricular assist device
Loforte (18)
Percutaneous—Amplatzer
+
Nguyen (19)
Percutaneous—Das AngelWings
+
Kavarana (20)
Percutaneous—CardioSeal
+
Coronary bypass
Schoevaerdts (21) Surgical (two patients)
+
Aortic root replacement
Brugts (22)
+
*Temporarily.
April 2015
Percutaneous—Amplatzer
over standard anticoagulation. With respect to the treatment of migraines, retrospective studies have shown a significant decrease in severity and frequency with closure of the PFOs (5). Unfortunately, the MIST trial revealed increased morbidity associated with PFO closure for patients with migraine headaches (6). There is a growing body of evidence for examining the role of PFOs in hypoxia. Classically, patients present with platypnea-orthodeoxia syndrome, positional hypoxia associated with the sensation of difficulty breathing, relieved in a recumbent position. Additionally, there are rare reports of acquired rightto-left shunts following cardiac or pulmonary surgery, detailed in Table 1 (7–22). Hypoxia secondary to PFO is believed to develop from an abnormal anatomic relation between the vena cava and the atrial septum, which directs venous blood flow from the inferior vena cava toward the atrial septum. The change in direction of blood flow can occur with positional changes or following a cardiopulmonary insult or operation, which distort the mediastinum and stretch the atrial septum (23). Acquired shunts have also been described secondary to a dilated aortic root that alters the atrial septum resulting in a shunt (24). As was the case with our patient, closure of the PFO in patients with hypoxia secondary to a right-to-left interatrial shunt has been shown to significantly reduce hypoxemia and associated symptoms. Although research on the effects of PFO closure for the treatment of hypoxia has been promising, it has been limited to small reports, predominantly case studies. Notably, in all of the cases detailed in Table 1, hypoxia improved immediately following PFO closure. Similarly, the case studies of patients with platypnea-orthodeoxia syndrome undergoing PFO closure report a significant postprocedural increase in blood oxygen saturation and excellent long-term outcomes (23, 25). 1.
2.
3.
4.
5.
6.
7.
Hagen PT, Scholz DG, Edwards WD. Incidence and size of patent foramen ovale during the first 10 decades of life: an autopsy study of 965 normal hearts. Mayo Clin Proc 1984;59(1):17–20. Carroll JD, Saver JL, Thaler DE, Smalling RW, Berry S, MacDonald LA, Marks DS, Tirschwell DL; RESPECT Investigators. Closure of patent foramen ovale versus medical therapy after cryptogenic stroke. N Engl J Med 2013;368(12):1092–1100. Furlan AJ, Reisman M, Massaro J, Mauri L, Adams H, Albers GW, Felberg R, Herrmann H, Kar S, Landzberg M, Raizner A, Wechsler L; CLOSURE I Investigators. Closure or medical therapy for cryptogenic stroke with patent foramen ovale. N Engl J Med 2012;366(11):991–999. Meier B, Kalesan B, Mattle HP, Khattab AA, Hildick-Smith D, Dudek D, Andersen G, Ibrahim R, Schuler G, Walton AS, Wahl A, Windecker S, Jüni P; PC Trial Investigators. Percutaneous closure of patent foramen ovale in cryptogenic embolism. N Engl J Med 2013;368(12):1083–1091. Nagpal SV, Lerakis S, Flueckiger PB, Halista M, Willis P, Block PC, Douglas JS, Morris DC, Liff DA, Stewart J, Devireddy C, Veledar E, Nahab FB, Babaliaros VC. Long-term outcomes after percutaneous patent foramen ovale closure. Am J Med Sci 2013;346(3):181–186. Dowson A, Mullen MJ, Peatfield R, Muir K, Khan AA, Wells C, Lipscombe SL, Rees T, De Giovanni JV, Morrison WL, Hildick-Smith D, Elrington G, Hillis WS, Malik IS, Rickards A. Migraine Intervention with STARFlex Technology (MIST) trial: a prospective, multicenter, double-blind, sham-controlled trial to evaluate the effectiveness of patent foramen ovale closure with STARFlex septal repair implant to resolve refractory migraine headache. Circulation 2008;117(11):1397–1404. Dlabal PW, Stutts BS, Jenkins DW, Harkleroad LE, Stanford WT. Cyanosis following right pneumonectomy: importance of patent foramen ovale. Chest 1982;81(3):370–372.
Usefulness of percutaneous closure of patent foramen ovale for hypoxia
205
8.
9. 10. 11.
12.
13. 14.
15. 16.
17.
206
Vacek JL, Foster J, Quinton RR, Savage PJ. Right-to-left shunting after lobectomy through a patent foramen ovale. Ann Thorac Surg 1985;39(6):576–578. Hazard PB. Postpneumonectomy right-to-left interatrial shunt: obliteration with balloon-tip vascular catheter. Crit Care Med 1987;15(6):618–619. Berry L, Braude S, Hogan J. Refractory hypoxaemia after pneumonectomy: diagnosis by transoesophageal echocardiography. Thorax 1992;47(1):60–61. Landzberg MJ, Sloss LJ, Faherty CE, Morrison BJ, Bittl JA, Bridges ND, Casale PN, Keane JF, Lock JE. Orthodeoxia-platypnea due to intracardiac shunting—relief with transcatheter double umbrella closure. Cathet Cardiovasc Diagn 1995;36(3):247–250. Godart F, Porte HL, Rey C, Lablanche JM, Wurtz A. Postpneumonectomy interatrial right-to-left shunt: successful percutaneous treatment. Ann Thorac Surg 1997;64(3):834–836. Alfaifi S, Lapinsky SE. Trepopnea due to interatrial shunt following lung resection. Chest 1998;113(6):1726–1727. Mall JW, Vogel B, Grohmann A, Müller JM. Re-opened foramen ovale—a rare cause of postoperative dyspnea following pneumonectomy. Thorac Cardiovasc Surg 2000;48(5):308–310. Pai VB, Vallurupalli S, Kasula SR, Hakeem A, Bhatti S. A change of heart: reopening of a foramen ovale. Can J Cardiol 2014;30(10):1250.e17–e18. Chopard R, Meneveau N. Right-to-left atrial shunting associated with aortic root aneurysm: a case report of a rare cause of platypnea-orthodeoxia syndrome. Heart Lung Circ 2013;22(1):71–75. Townsend M, MacIver DH, Bilku R. Platypnoea-orthodeoxia syndrome in association with an ascending aortic aneurysm. Eur J Echocardiogr 2007;8(1):50–52.
18. Loforte A, Violini R, Musumeci F. Transcatheter closure of patent foramen ovale for hypoxemia during left ventricular assist device support. J Card Surg 2012;27(4):528–529. 19. Nguyen DQ, Das GS, Grubbs BC, Bolman RM 3rd, Park SJ. Transcatheter closure of patent foramen ovale for hypoxemia during left ventricular assist device support. J Heart Lung Transplant 1999;18(10):1021–1023. 20. Kavarana MN, Rahman FA, Recto MR, Dowling RD. Transcatheter closure of patent foramen ovale after left ventricular assist device implantation: intraoperative decision making. J Heart Lung Transplant 2005;24(9):1445. 21. Schoevaerdts D, González M, Evrard P, Buche M, Installé E. Patent foramen ovale: a cause of significant post-coronary artery bypass grafting morbidity. Cardiovasc Surg 2002;10(6):615–617. 22. Brugts JJ, Liesting C, Kofflard MJ, van den Bos EJ. Right-to-left atrial shunting with normal intracardiac pressures following cardiac surgery: pathophysiology and management. J Card Surg 2012;27(3):335–337. 23. Blanche C, Noble S, Roffi M, Testuz A, Müller H, Meyer P, Bonvini JM, Bonvini RF. Platypnea-orthodeoxia syndrome in the elderly treated by percutaneous patent foramen ovale closure: a case series and literature review. Eur J Intern Med 2013;24(8):813–817. 24. Eicher JC, Bonniaud P, Baudouin N, Petit A, Bertaux G, Donal E, Piéchaud JF, David M, Louis P, Wolf JE. Hypoxaemia associated with an enlarged aortic root: a new syndrome? Heart 2005;91(8):1030–1035. 25. Fenster BE, Nguyen BH, Buckner JK, Freeman AM, Carroll JD. Effectiveness of percutaneous closure of patent foramen ovale for hypoxemia. Am J Cardiol 2013;112(8):1258–1262.
Baylor University Medical Center Proceedings
Volume 28, Number 2
We report a patient with hypoxia secondary to a right-to-left shunt through a patent foramen ovale, following aortic root, valve, and arch replacement due to an aortic dissection in the setting of the Marfan syndrome. Following the operation, he failed extubation twice due to hypoxia. An extensive workup revealed a right-to-left shunt previously not seen. The patent foramen ovale was closed using a percutaneous closure device. Following closure, our patient was extubated without difficulty and has done well postoperatively.
A
pproximately 25% of the general population is estimated to have a patent foramen ovale (PFO). These small atrial septal defects, present from birth, are usually asymptomatic and found incidentally by echocardiogram or at autopsy (1). We describe the benefit of closure of a PFO for postoperative hypoxia. CASE DESCRIPTION A 23-year-old Hispanic man with the Marfan syndrome presented with acute chest pain that radiated to his back. The diagnosis of a dilated aortic root and a type B aortic dissection was made quickly by computed tomography scan with contrast. He underwent surgical repair using a two-staged “elephant trunk” procedure. The initial stage of the procedure consists of an aortic valve, root, and arch replacement, including leaving an elephant trunk portion of the graft that hangs down into the descending aorta. Finally the descending thoracic aorta is wrapped at that level of the diaphragm. The second stage of the procedure uses a stent graft, via an endovascular approach, to connect the elephant trunk with the wrapped portion of the aorta. Following the first stage, his postoperative course was complicated by recurrent hypoxia. He underwent two attempted extubations on postoperative days 1 and 7, but the hypoxia persisted. A PFO with a significant right-to-left shunt was found on transesophageal echocardiogram with bubble study (Figure 1). On postoperative day 9, a percutaneous closure procedure was performed via the right femoral vein. A #25 Amplatzer Cribriform Septal Occluder (AGA Medical Corp., Plymouth, MN) was deployed in the PFO, and placement was confirmed with intracardiac echocardiography and fluoroscopy (Figure 2). A negative echocardiographic bubble study at the conclusion of
204
Figure 1. Transesophageal echocardiogram with bubble study, showing rightto-left shunt through a patent foramen ovale. RA indicates right atrium, LA, left atrium; PFO, patent foramen ovale.
the procedure confirmed resolution of the right-to-left shunt. On day 10, extubation was successful and normal oxygen saturation was maintained. The patient was discharged from the hospital on postoperative day 22. Five weeks later, he underwent stage 2 of the “elephant trunk” procedure without postoperative respiratory complications. He continues to do well 5 months following the second stage of the procedure. DISCUSSION Despite the severity of potential consequences of a PFO, hypothesized benefits of closing PFOs, specifically for migraine headaches and strokes, have not resulted in clinical benefit over standard medical management. Three large randomized controlled trials, RESPECT (2), CLOSURE I (3), and PC Trial (4), failed to show a benefit of PFO closure over medical management for the prevention of recurrent paradoxical embolism. The RESPECT trial did, however, demonstrate increased safety and From the Division of Cardiology, Department of Internal Medicine, Baylor Hamilton Heart and Vascular Hospital and Baylor University Medical Center at Dallas. Corresponding author: James W. Choi, MD, Cardiology Consultants of Texas, Baylor Heart and Vascular Hospital, 621 N. Hall Street, Suite 400, Dallas, TX 75226 (e-mail: [email protected]). Proc (Bayl Univ Med Cent) 2015;28(2):204–206
Figure 2. A cineflourographic image of the #25 Amplatzer Cribriform Septal Occluder (AGA Medical Corp, Plymouth, MN) following deployment.
efficacy of the Amplatzer PFO Occluder device over the previously used STARFlex Septal Closure System (2, 4). While there is ample evidence through observational studies for the efficacy of PFO closure in prevention of recurrent embolic strokes, no studies have been able to provide evidence for significant benefit Table 1. Previously published cases discussing closure of patent foramen ovale for hypoxia Clinical setting
First author (reference)
PostDlabal (7) pneumonectomy Vacek (8)
Closure method Surgical
Hypoxia lessened +
Surgical
+
Hazard (9)
Percutaneous—balloon
+*
Berry (10)
Surgical
+
Landzberg (11)
Percutaneous—clamshell
+
Godart (12)
Percutaneous—button
+
Alfaifi (13)
Surgical
+
Mall (14)
Surgical
+
Pai (15)
Percutaneous—Amplatzer
+
Thoracic aortic maneurysm
Chopard (16)
Percutaneous—Amplatzer
+
Townsend (17)
Surgical
+
Left ventricular assist device
Loforte (18)
Percutaneous—Amplatzer
+
Nguyen (19)
Percutaneous—Das AngelWings
+
Kavarana (20)
Percutaneous—CardioSeal
+
Coronary bypass
Schoevaerdts (21) Surgical (two patients)
+
Aortic root replacement
Brugts (22)
+
*Temporarily.
April 2015
Percutaneous—Amplatzer
over standard anticoagulation. With respect to the treatment of migraines, retrospective studies have shown a significant decrease in severity and frequency with closure of the PFOs (5). Unfortunately, the MIST trial revealed increased morbidity associated with PFO closure for patients with migraine headaches (6). There is a growing body of evidence for examining the role of PFOs in hypoxia. Classically, patients present with platypnea-orthodeoxia syndrome, positional hypoxia associated with the sensation of difficulty breathing, relieved in a recumbent position. Additionally, there are rare reports of acquired rightto-left shunts following cardiac or pulmonary surgery, detailed in Table 1 (7–22). Hypoxia secondary to PFO is believed to develop from an abnormal anatomic relation between the vena cava and the atrial septum, which directs venous blood flow from the inferior vena cava toward the atrial septum. The change in direction of blood flow can occur with positional changes or following a cardiopulmonary insult or operation, which distort the mediastinum and stretch the atrial septum (23). Acquired shunts have also been described secondary to a dilated aortic root that alters the atrial septum resulting in a shunt (24). As was the case with our patient, closure of the PFO in patients with hypoxia secondary to a right-to-left interatrial shunt has been shown to significantly reduce hypoxemia and associated symptoms. Although research on the effects of PFO closure for the treatment of hypoxia has been promising, it has been limited to small reports, predominantly case studies. Notably, in all of the cases detailed in Table 1, hypoxia improved immediately following PFO closure. Similarly, the case studies of patients with platypnea-orthodeoxia syndrome undergoing PFO closure report a significant postprocedural increase in blood oxygen saturation and excellent long-term outcomes (23, 25). 1.
2.
3.
4.
5.
6.
7.
Hagen PT, Scholz DG, Edwards WD. Incidence and size of patent foramen ovale during the first 10 decades of life: an autopsy study of 965 normal hearts. Mayo Clin Proc 1984;59(1):17–20. Carroll JD, Saver JL, Thaler DE, Smalling RW, Berry S, MacDonald LA, Marks DS, Tirschwell DL; RESPECT Investigators. Closure of patent foramen ovale versus medical therapy after cryptogenic stroke. N Engl J Med 2013;368(12):1092–1100. Furlan AJ, Reisman M, Massaro J, Mauri L, Adams H, Albers GW, Felberg R, Herrmann H, Kar S, Landzberg M, Raizner A, Wechsler L; CLOSURE I Investigators. Closure or medical therapy for cryptogenic stroke with patent foramen ovale. N Engl J Med 2012;366(11):991–999. Meier B, Kalesan B, Mattle HP, Khattab AA, Hildick-Smith D, Dudek D, Andersen G, Ibrahim R, Schuler G, Walton AS, Wahl A, Windecker S, Jüni P; PC Trial Investigators. Percutaneous closure of patent foramen ovale in cryptogenic embolism. N Engl J Med 2013;368(12):1083–1091. Nagpal SV, Lerakis S, Flueckiger PB, Halista M, Willis P, Block PC, Douglas JS, Morris DC, Liff DA, Stewart J, Devireddy C, Veledar E, Nahab FB, Babaliaros VC. Long-term outcomes after percutaneous patent foramen ovale closure. Am J Med Sci 2013;346(3):181–186. Dowson A, Mullen MJ, Peatfield R, Muir K, Khan AA, Wells C, Lipscombe SL, Rees T, De Giovanni JV, Morrison WL, Hildick-Smith D, Elrington G, Hillis WS, Malik IS, Rickards A. Migraine Intervention with STARFlex Technology (MIST) trial: a prospective, multicenter, double-blind, sham-controlled trial to evaluate the effectiveness of patent foramen ovale closure with STARFlex septal repair implant to resolve refractory migraine headache. Circulation 2008;117(11):1397–1404. Dlabal PW, Stutts BS, Jenkins DW, Harkleroad LE, Stanford WT. Cyanosis following right pneumonectomy: importance of patent foramen ovale. Chest 1982;81(3):370–372.
Usefulness of percutaneous closure of patent foramen ovale for hypoxia
205
8.
9. 10. 11.
12.
13. 14.
15. 16.
17.
206
Vacek JL, Foster J, Quinton RR, Savage PJ. Right-to-left shunting after lobectomy through a patent foramen ovale. Ann Thorac Surg 1985;39(6):576–578. Hazard PB. Postpneumonectomy right-to-left interatrial shunt: obliteration with balloon-tip vascular catheter. Crit Care Med 1987;15(6):618–619. Berry L, Braude S, Hogan J. Refractory hypoxaemia after pneumonectomy: diagnosis by transoesophageal echocardiography. Thorax 1992;47(1):60–61. Landzberg MJ, Sloss LJ, Faherty CE, Morrison BJ, Bittl JA, Bridges ND, Casale PN, Keane JF, Lock JE. Orthodeoxia-platypnea due to intracardiac shunting—relief with transcatheter double umbrella closure. Cathet Cardiovasc Diagn 1995;36(3):247–250. Godart F, Porte HL, Rey C, Lablanche JM, Wurtz A. Postpneumonectomy interatrial right-to-left shunt: successful percutaneous treatment. Ann Thorac Surg 1997;64(3):834–836. Alfaifi S, Lapinsky SE. Trepopnea due to interatrial shunt following lung resection. Chest 1998;113(6):1726–1727. Mall JW, Vogel B, Grohmann A, Müller JM. Re-opened foramen ovale—a rare cause of postoperative dyspnea following pneumonectomy. Thorac Cardiovasc Surg 2000;48(5):308–310. Pai VB, Vallurupalli S, Kasula SR, Hakeem A, Bhatti S. A change of heart: reopening of a foramen ovale. Can J Cardiol 2014;30(10):1250.e17–e18. Chopard R, Meneveau N. Right-to-left atrial shunting associated with aortic root aneurysm: a case report of a rare cause of platypnea-orthodeoxia syndrome. Heart Lung Circ 2013;22(1):71–75. Townsend M, MacIver DH, Bilku R. Platypnoea-orthodeoxia syndrome in association with an ascending aortic aneurysm. Eur J Echocardiogr 2007;8(1):50–52.
18. Loforte A, Violini R, Musumeci F. Transcatheter closure of patent foramen ovale for hypoxemia during left ventricular assist device support. J Card Surg 2012;27(4):528–529. 19. Nguyen DQ, Das GS, Grubbs BC, Bolman RM 3rd, Park SJ. Transcatheter closure of patent foramen ovale for hypoxemia during left ventricular assist device support. J Heart Lung Transplant 1999;18(10):1021–1023. 20. Kavarana MN, Rahman FA, Recto MR, Dowling RD. Transcatheter closure of patent foramen ovale after left ventricular assist device implantation: intraoperative decision making. J Heart Lung Transplant 2005;24(9):1445. 21. Schoevaerdts D, González M, Evrard P, Buche M, Installé E. Patent foramen ovale: a cause of significant post-coronary artery bypass grafting morbidity. Cardiovasc Surg 2002;10(6):615–617. 22. Brugts JJ, Liesting C, Kofflard MJ, van den Bos EJ. Right-to-left atrial shunting with normal intracardiac pressures following cardiac surgery: pathophysiology and management. J Card Surg 2012;27(3):335–337. 23. Blanche C, Noble S, Roffi M, Testuz A, Müller H, Meyer P, Bonvini JM, Bonvini RF. Platypnea-orthodeoxia syndrome in the elderly treated by percutaneous patent foramen ovale closure: a case series and literature review. Eur J Intern Med 2013;24(8):813–817. 24. Eicher JC, Bonniaud P, Baudouin N, Petit A, Bertaux G, Donal E, Piéchaud JF, David M, Louis P, Wolf JE. Hypoxaemia associated with an enlarged aortic root: a new syndrome? Heart 2005;91(8):1030–1035. 25. Fenster BE, Nguyen BH, Buckner JK, Freeman AM, Carroll JD. Effectiveness of percutaneous closure of patent foramen ovale for hypoxemia. Am J Cardiol 2013;112(8):1258–1262.
Baylor University Medical Center Proceedings
Volume 28, Number 2
