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eComment: Cor triatriatum and cardiac hemolytic anemia

National Cardiothoracic Centre, Korle Bu TeachingHospital, PO Box KB 846, Korle Bu, Accra, Ghana

Hemolytic anemia: an unusual presentation of cor triatriatum sinistrum

Mahmoud and colleagues report [1] 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 [2], the Bernoulli equation yields a shear stress of 4000 dynes/cm² at a pressure gradient of 50 mmHg; Mahmoud and colleagues [1] 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 [2]). Clearly, other factors besides the pressure gradient are operative. According to Garcia and others [3, 4], 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 ‘non-hemolytic’ 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 [1], 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.

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1. 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.[Abstract/Free Full Text]
2. 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.[Medline]
3. 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.[Abstract]
4. 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.[Abstract/Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Frank Edwin Kow Entsua-Mensah Kwabena Frimpong-Boateng Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Edwin, F. Articles by Frimpong-Boateng, K. Search for Related Content PubMed PubMed Citation Articles by Edwin, F. Articles by Frimpong-Boateng, K. Related Collections Related Article