Chiari's network: normal anatomic variant or risk factor for arterial embolic events?

II. Medizinische Abteilung, Allgemeines Krankenhaus St. Georg, Hamburg, Germany.

OBJECTIVES. This study was performed to assess the prevalence of Chiari's network in patients undergoing transesophageal echocardiography and to determine whether this anomaly is associated with other cardiac lesions or is characterized by typical clinical findings. BACKGROUND. Chiari's network is a congenital remnant of the right valve of the sinus venosus. It has been found in 1.3% to 4% of autopsy studies and is believed to be of little clinical consequence. METHODS. Video recordings of 1,436 consecutive adult patients evaluated by transesophageal echocardiography over a 30-month period were reviewed for the presence of Chiari's network. Echocardiographic contrast studies had been performed in all patients with Chiari's network and were compared with those of 160 consecutive patients without a Chiari net, serving as a control group. RESULTS. Chiari's network was present in 29 of 1,436 patients (prevalence 2%). A frequently associated finding was a patent foramen ovale in 24 (83%) of the 29 patients with Chiari's network versus 44 (28%) of 160 control patients (p < 0.001). Intense right-to-left shunting occurred significantly more often in patients with Chiari's network than in control patients (16 [55%] of 29 patients vs. 19 [12%] of 160 control patients, p < 0.001). Another frequent association was an atrial septal aneurysm in 7 (24%) of 29 patients. The indication for transesophageal echocardiography was a suspected cardiac source of arterial embolism in 24 (83%) of 29 patients with a Chiari net, 13 of whom (54%) had recurrent embolic events. Chiari's network was significantly more common in patients with unexplained arterial embolism than in patients evaluated for other indications (24 [4.6%] of 522 patients vs. 5 [0.5%] of 914 patients, p < 0.001). Potential causes for arterial embolism were present in 9 of the 24 patients with a Chiari net and embolic events (atrial septal aneurysm in 7, cerebrovascular lesion in 2). In 15 (62%) of 24 patients only a patent foramen ovale could be identified. Three patients had deep venous thrombosis and pulmonary embolism at the time of arterial embolism; none had a thrombus detected within the network. CONCLUSIONS. In patients undergoing transesophageal echocardiography, the prevalence of Chiari's network was 2%, which is consistent with autopsy studies. By maintaining an embryonic right atrial flow pattern into adult life and directing the blood from the inferior vena cava preferentially toward the interatrial septum, Chiari's network may favor persistence of a patent foramen ovale and formation of an atrial septal aneurysm and facilitate paradoxic embolism.

This article has been cited by other articles:

				F. Saremi and S. Krishnan Cardiac Conduction System: Anatomic Landmarks Relevant to Interventional Electrophysiologic Techniques Demonstrated with 64-Detector CT RadioGraphics, November 1, 2007; 27(6): 1539 - 1565. [Abstract] [Full Text] [PDF]

				M. R. Sukernik and E. Bennett-Guerrero The Incidental Finding of a Patent Foramen Ovale During Cardiac Surgery: Should It Always Be Repaired? A Core Review Anesth. Analg., September 1, 2007; 105(3): 602 - 610. [Abstract] [Full Text] [PDF]

				A. Kessel-Schaefer, A. Linka, R. Pretre, and P. Buser Inferior sinus venosus defect associated with incomplete cor triatriatum dexter and patent foramen ovale Eur J Echocardiogr, June 1, 2006; 7(3): 239 - 242. [Abstract] [Full Text] [PDF]

				B. Meier Patent Foramen Ovale, Guilty But Only as a Gang Member and for a Lesser Crime J. Am. Coll. Cardiol., January 17, 2006; 47(2): 446 - 448. [Full Text] [PDF]

				H. Hara, R. Virmani, E. Ladich, S. Mackey-Bojack, J. Titus, M. Reisman, W. Gray, M. Nakamura, M. Mooney, A. Poulose, et al. Patent Foramen Ovale: Current Pathology, Pathophysiology, and Clinical Status J. Am. Coll. Cardiol., November 1, 2005; 46(9): 1768 - 1776. [Abstract] [Full Text] [PDF]

				S. Homma and R. L. Sacco Patent Foramen Ovale and Stroke Circulation, August 16, 2005; 112(7): 1063 - 1072. [Full Text] [PDF]

				J-C Eicher, P Bonniaud, N Baudouin, A Petit, G Bertaux, E Donal, J F Piechaud, M David, P Louis, and J E Wolf Hypoxaemia associated with an enlarged aortic root: a new syndrome? Heart, August 1, 2005; 91(8): 1030 - 1035. [Abstract] [Full Text] [PDF]

				D. M. Payne, R. J. F. Baskett, and G. M. Hirsch Infectious endocarditis of a Chiari network Ann. Thorac. Surg., October 1, 2003; 76(4): 1303 - 1305. [Abstract] [Full Text] [PDF]

				S. Homma, R. L. Sacco, M. R. Di Tullio, R. R. Sciacca, J. P. Mohr, and PICSS Investigators Atrial anatomy in non-cardioembolic stroke patients: Effect of medical therapy J. Am. Coll. Cardiol., September 17, 2003; 42(6): 1066 - 1072. [Abstract] [Full Text] [PDF]

				R. Castello and T. G. Brott Patent foramen ovale: friend or foe? J. Am. Coll. Cardiol., September 17, 2003; 42(6): 1073 - 1075. [Full Text] [PDF]

				C. J. Rodriguez, S. Homma, R. L. Sacco, M. R. Di Tullio, R. R. Sciacca, and J.P. Mohr Race-Ethnic Differences in Patent Foramen Ovale, Atrial Septal Aneurysm, and Right Atrial Anatomy Among Ischemic Stroke Patients Stroke, September 1, 2003; 34(9): 2097 - 2102. [Abstract] [Full Text] [PDF]

				E. K. Kerut, W. T. Norfleet, G. D. Plotnick, and T. D. Giles Patent foramen ovale: a review of associated conditions and the impact of physiological size J. Am. Coll. Cardiol., September 1, 2001; 38(3): 613 - 623. [Abstract] [Full Text] [PDF]

				B. Censori, F. Colombo, M. G. Valsecchi, L. Clivati, A. Zonca, M. Camerlingo, L. Casto, M. S. De Tommasi, and A. Mamoli Early transoesophageal echocardiography in cryptogenic and lacunar stroke and transient ischaemic attack J. Neurol. Neurosurg. Psychiatry, May 1, 1998; 64(5): 624 - 627. [Abstract] [Full Text] [PDF]