Coconut atrium

Coconut atrium

Coconut atrium is the term coined for complete calcification of the left atrium in chronic rheumatic valvular heart disease [1]. The stimulus for calcification could be the chronic inflammatory process of rheumatic fever as well as the strain due to atrial overload. Reduced left atrial compliance leads to elevation in pressures which gets transmitted to the pulmonary venous system, pulmonary arteries and sequentially to the right heart. Chest X-ray will show the calcified outline of the left atrium [2], which can be further confirmed by computerized tomographic (CT) scan.
Coconut atrium has also been called as ‘porcelain atrium’ akin to the ‘porcelain aorta’ [3]. Presence of such extensive calcification is important in the setting of mitral valve surgery. Mitral valve replacement procedures[4] and radiotherapy  [5] can also predispose to calcification. Coconut left atrium has been described 23 years after mitral valve replacement for chronic mitral stenosis, in spite of normal prosthetic mitral valve function [6]. The patient had exertional dyspnea and severe pulmonary hypertension.

Coconut atrium can predispose to atrial fibrillation and systemic embolization [7]. Another term applied to extensive left atrial calcification is mold-like calcification [8]. Due to difficulty in replacing the mitral valve, total endoatriectomy had to be done in a patient with mold like calcification of left atrium [9].

Endoatriectomy is an option when only an endocardial shell of calcification is present. When the entire left atrium up to epicardium is calcified, accessing the left atrium for mitral valve replacement is almost impossible. Calcification may extend to the pulmonary veins [10].

Preoperative knowledge on the extent calcification of left atrium is very important for the surgeon before making a decision to operate on patient with long standing mitral stenosis.

References

1. Onishi T, Idei Y, Otsui K, Iwata S, Suzuki A, Ozawa T, Domoto K, Takei A, Inamoto S, Inoue N. Coconut atrium in long-standing rheumatic valvular heart disease. Am J Case Rep. 2015 Mar 30;16:191-5.
2. Reddy D, Madansein R. Cracking the coconut: extensive calcification of the left atrium. Ann Thorac Surg. 2013 Dec;96(6):2249.
   
3. Anandan PK, Shukkarbhai PJ, Bhatt P, Manjunath CN. Coconut atrium. Eur Heart J Cardiovasc Imaging. 2015 Jul;16(7):814.
4. Lee WJ, Son CW, Yoon JC, Jo HS, Son JW, Park KH, Lee SH, Shin DG, Hong GR, Park JS, Kim YJ. Massive left atrial calcification associated with mitral valve replacement. J Cardiovasc Ultrasound. 2010 Dec;18(4):151-3.
5. Jenkins NP, Brooks NH, Greaves M. Coconut atrium following thoracic radiotherapy. Heart. 2004 Dec;90(12):1376.
6. Meyners W, Peters S. A coconut left atrium 23 years after mitral valve replacement for chronic mitral stenosis. Z Kardiol. 2003 Jan;92(1):82-3.
   
7. Jørgensen M, Gill S, Thomassen A, Søndergaard EV, Diederichsen LP, Diederichsen AC. Coconut atrium, an exotic source of cardiac emboli. Int J Cardiol. 2014 Dec 20;177(3):e97-8.
8. Funada A, Kanzaki H, Kanzaki S, Takahama H, Amaki M, Hasegawa T, Yamada N, Kitakaze M. Coconut left atrium. Int J Cardiol. 2012 Jan 26;154(2):e42-4.
9. G Ruvolo, E Greco, G Speziale, D Mercogliano, B Marino. “Mold-like” calcification of the left atrium and of the pulmonary veins. Total endoatriectomy in a patient undergoing mitral valve replacement. Eur J Cardiothorac Surg. 1994;8(1):54-5.
10. C Del Campo, P Weinstein, C Kunnelis, P DiStefano, G M Ebers. Coconut atrium: transmural calcification of the entire left atrium. Tex Heart Inst J. 2000;27(1):49-51.