eComment: Cor triatriatum and cardiac hemolytic anemia Frank Edwin, Ernest A. Aniteye, Kow Entsua-Mensah and Kwabena Frimpong-Boateng Interact CardioVasc Thorac Surg 2009;9:383DOI: 10.1510/icvts.2008.201293A
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Interactive Cardiovascular and Thoracic Surgery is the official journal of the European Association for Cardio-thoracic Surgery (EACTS) and the European Society for Cardiovascular Surgery (ESCVS). Copyright © 2009 by European Association for Cardio-thoracic Surgery. Print ISSN: 1569-9293.
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ARTICLE IN PRESS A.-B.S. Mahmoud et al. / Interactive CardioVascular and Thoracic Surgery 9 (2009) 382–383
was applied and the heart was arrested with cold blood cardioplegia, and mild systemic hypothermia was used throughout the procedure. The atrial septum was determined and the cor triatriatum was reached via transseptal approach. The membrane was successfully excised around the circumference of the atrial septum and left atrial free wall. Care was taken to avoid injury to the mitral valve apparatus and atrial free wall. The patient had an uneventful postoperative course. Postoperatively, her hemoglobin returned to normal, her lactate dehydrogenase gradually approached the normal range, the reticulocyte count was normalized. Postoperative echocardiography revealed no residual gradient in the left atrium. The patient was discharged in good condition on postoperative day 5. Follow-up shows still normal hemoglobin of 14.5 gydl. 3. Comment In patients with stenotic lesions, the mechanism for intravascular hemolysis is considered to be related to turbulence and shear stress produced by flow through stenosed or incompetent orifices. In the adult, red cell shearing stress above 3000 dynesycm2 can increase hemolysis w2, 3x. There is a report of a 50-mmHg peak gradient through left ventricular outflow tract or aortic valve calculated to have a shear stress of 4000 dynesycm2 w4x. Our patient is an infant and had a maximal peak gradient of 35 mmHg with echocardiography. This high gradient in an infant may be enough to cause hemolysis. We determined that cor triatriatum might cause hemolytic anemia in our case, as was evidenced by the laboratory findings and clinical presentation. In our case, the stenotic orifice of the cor triatriatum caused hemolysis which was surgically fully corrected.
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eComment: Cor triatriatum and cardiac hemolytic anemia Authors: Frank Edwin, National Cardiothoracic Centre, Korle Bu Teaching Hospital, PO Box KB 846, Korle Bu, Accra, Ghana; Ernest A. Aniteye, Kow Entsua-Mensah, Kwabena Frimpong-Boateng doi:10.1510/icvts.2008.201293A Mahmoud and colleagues report w1x is indeed a rare case of cardiac hemolytic anemia occurring in unrepaired cor triatriatum. Cardiac hemolytic anemia is well described after prosthetic heart valve replacement and also following congenital heart repairs with and without prosthetic materials. It is exceedingly rare in unrepaired congenital heart disease. It is generally held that a high pressure gradient generating turbulent shear stress is the predominant factor involved and prosthetic materials enhance the hemolytic potential of turbulent jets. Many congenital cardiovascular lesions create high pressure gradients; one must wonder why cardiac hemolytic anemia does not occur more frequently in the preoperative setting. Possibly, other hydrodynamic factors are contributory to the development of clinical hemolysis. According to Nevaril’s group w2x, the Bernoulli equation yields a shear stress of 4000 dynes/cm2 at a pressure gradient of 50 mmHg; Mahmoud and colleagues w1x report a pressure gradient of 35 mmHg, the equivalent of 2800 dynes/cm2 shear stress which is below the threshold for clinically significant hemolysis (3000 dynes/cm2 w2x). Clearly, other factors besides the pressure gradient are operative. According to Garcia and others w3, 4x, clinical hemolysis is associated with distinct patterns of flow disturbance recognizable by transesophageal echocardiography and associated with high shear stress by numeric flow simulation. In their report, three types of jets consistently caused significant shear stress for clinical hemolysis: the collision jet (involving sudden deceleration), the fragmentation jet (a jet divided by a solid structure) and the rapid acceleration jet (a jet through a small orifice -2 mm). The shear stress associated with each type of jet was estimated to be 4500, 6000 and 4500 dynes/cm2, respectively. The ‘nonhemolytic’ jets described, the free jet and the deceleration jet were both associated with shear stresses -1000 dynes/cm2. From their report, any hemodynamic derangement associated with a high shear stress is capable of producing clinical hemolysis. It is possible that in this reported case of cor triatriatum w1x, any of the ‘hemolytic’ jets could have contributed to clinical hemolysis even in the absence of an extreme pressure gradient across the communicating orifice. We surmise from the literature review that the important hydrodynamic mechanisms involved in cardiac hemolytic anemia include the following factors – turbulent shear stress and the jet geometry, orifice size, pressure gradient, presence of intracardiac prosthetic materials, and intrinsic red cell membrane abnormalities.
References
References w1x Niwayama G. Cor triatriatum. Am Heart J 1960;59:291–317. w2x Nevaril CG, Lynch EC, Alfrey CP Jr, Hellums JD. Erythrocyte damage and destruction induced by shearing stress. J Lab Clin Med 1968;71:784– 790. w3x Maccallum RN, Lynch CE, Hellums JD, Alfrey CP Jr. Fragility of abnormal erythrocytes evaluated by response to shear stress. J Lab Clin Med 1975;85:67–74. w4x Jacobson RJ, Rath CE, Perloff JK. Intravascular haemolysis and thrombocytopenia in left ventricular outflow obstruction. Br Heart J 1973;35:849–854.
w1x Mahmoud A-BS, Jamjoom AA, Kouatli AA, Bayoumy MS. Hemolytic anemia: an unusual presentation of cor triatriatum sinistrum. Interact CardioVasc Thorac Surg 2009;9:382–383. w2x Nevaril CG, Lynch EC, Alfrey CP, Hellums JD Jr. Erythrocyte damage and destruction induced by shearing stress. J Lab Clin Med 1968;71:784– 790. w3x Garcia MJ, Vandervoort P, Stewart WJ, Lytle BW, Cosgrove DM 3rd, Thomas JD, Griffin BP. Mechanisms of hemolysis with mitral prosthetic regurgitation: study using transesophageal echocardiography and fluid dynamic simulation. J Am Coll Cardiol 1996;27:399–406. w4x Yeo TC, Freeman WK, Schaff HV, Orszulak TA. Mechanisms of hemolysis after mitral valve repair: assessment by serial echocardiography. J Am Coll Cardiol 1998;32:717–723.
Case Report
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eComment: Cor triatriatum and cardiac hemolytic anemia Frank Edwin, Ernest A. Aniteye, Kow Entsua-Mensah and Kwabena Frimpong-Boateng Interact CardioVasc Thorac Surg 2009;9:383DOI: 10.1510/icvts.2008.201293A This information is current as of February 2, 2011 Updated Information & Services
including high-resolution figures, can be found at: http://icvts.ctsnetjournals.org/cgi/content/full/9/2/383
References
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