ABSTRACT


Background: Cardiovascular disease is one of the major health problems all over the world. Yemen is one of the least developed countries in the Gulf and cardiovascular diseases contribute a big economic burden. Echocardiography has revolutionized the practice of cardiology and its role as a non-invasive diagnostic tool for both congenital and acquired cardiac lesions, however complex is well established. Along with 2-D, M mode and Doppler. New echocardiographic modalities like stress Echo, tissue Doppler, harmonic imaging and contrast echocardiography are also emerging in Yemen. The aim of this study was to find the prevelance of both organic and functional mitral regurgitation (MR) by echocardiography in our population.

Materials and Methods: Using Sonos 1000 & 5500 HP Echocardiography machines, all the cases of MR diagnosed over the past 6 months in Al-Thawra Modern Teaching Hospital, Sana’a, were retrospectively reviewed. Mitral regurgitation was classified as organic if the mitral apparatus was found to be abnormal, and functional in the case of MR with a normal looking mitral valve.

Results: A total of thirteen hundred and thirty cases of MR were diagnosed during the study period. The mean age was 44.7 years with a standard deviation (SD) of ± 19.4 and the age group of 51-60 years was the dominant group making up 20.8%. Mitral regurgitation was slightly more common in males than females with 56.5% vs 43.5%. Functional MR was slightly more common than organic (51.7% vs 48.3%). Rheumatic heart disease (22.9%) was the most common cause of organic MR while Mitral valve prolapse was only found in 6.3% of this group. Hypertensive heart disease 21.7% was the most frequent etiology of functional MR. On the basis of severity, mild MR was the diagnosis in 65.5%, trivial in 15.4%, moderate in 12.9% and severe MR was found in 5.7%. Heart Views. 2008;9(2): 61-63.
© Gulf Heart Association 2008.

Keywords: ¨ Mitral regurgitation, ¨ Yemen rheumatic heart disease.




Introduction


  
     Mitral Regurgitation is one of the most common lesions seen in the echocardiography laboratory, Al-Thawra hospital, Sana’a1. The usual causes of organic mitral regurgitation are infective endocarditis, myxomatous degeneration of the mitral valve including mitral valve prolapse, collagen vascular diseases, spontaneous rupture of the chordae tendineae and rheumatic fever/ rheumatic heart disease. Pathophysiological stages of mitral regurgitation progress from acute mitral regurgitation to chronic compensated and then to chronic decompensated mitral regurgitation. A holosystolic apical murmur alerts the examiner that mitral regurgitation is present. An S3 (third heart sound) suggests that the disease is severe. Echocardiography not only confirms the diagnosis of MR but also highlights its hemodynamic effects on the heart. Unlike the stenotic lesions, regurgitant lesions may progress insidiously, causing left ventricular damage before symptoms develop. Thus, the presence of symptoms in chronic mitral regurgitation usually indicates the need for valve surgery, surgery is also recommended if asymptomatic left ventricular dysfunction has begun to develop. Medical treatment using angiotensin converting enzyme inhibitors, Angiotensin Agonist blockers or beta-blockers have a limited role and there is no evidence that these agents postpone the timing of surgery or improve the hemodynamics and may be even harmful in cases of mitral regurgitation due to mitral valve prolapse and hypertrophic cardiomyopathy.

     In this survey, we studied the prevalence of organic versus functional MR diagnosed in a Yemeni population.
 

Graph 1: Age distribution among MR patients.

Materials and methods

Thirteen hundred and thirty patients with mitral regurgitation were diagnosed in Al-Thawra Hospital over a six month period. Phased array HP 5500 and 1000 echocardiography machines with probe range of 2.5-3.7 MHz were used in the study. 2-D, M-Mode, pulsed wave Doppler, color coded Doppler and continuous wave Doppler echo modalities were used in the examination. Parasternal, apical and subcostal views with different angulations were applied. Assessment of regurgitant jet characteristics including its length, height, area, and width at the vena contracta was measured to assess the severity of MR. Quantification of mitral regurgitation was done using the flow conversion method2.



Results


     
    Over a six month period, 1330 patients with mitral regurgitation were diagnosed. The mean age was 44.7 years with a SD of ± 19.4. Age groups (Graph 1) between 40-50 years represented 18.9% and 20.8% respectively.

    Male dominance was noted with male to female distribution of 56.2% and 43.5% respectively. Functional MR was slightly more common than organic MR (51.7% vs 48.3%).

     The commonest cause of organic MR was rheumatic heart disease with 22.9% while mitral valve prolapse represented 6.3% of all cases. The commonest cause in the functional group was hypertensive heart disease with 21.7% of all MR cases in the study group.

     Mild MR was commonest representing 65.5%, trivial 15.4%, moderate 12.9% while severe MR occurred in 5.7% in this study (Graph 2).

         

Graph 2: Frequency of MR grades.

 
Discussion


      Al-Thawra Modern Teaching Hospital is the major hospital in Yemen, with more than 600 beds. The cardiovascular infrastructure existing in the hospital has helped to establish a sustained cardiac surgery program. Doppler echocardiography is the most sensitive technique available for detection of valve regurgitation and care must be taken to distinguish functional versus organic regurgitation. Mild retrograde flow disturbances are frequently detected in normal subjects1,3 and significant regurgitation may be inaudible on auscultation in unstable symptomatic patients4,5. Because the finding of clinically silent valvular regurgitation in an asymptomatic patient carries an unknown significance, performance of Doppler echocardiography to exclude valvular heart disease in an asymptomatic patient with a normal physical examination is not indicated. In our study, the main cause of organic MR was rheumatic heart disease (RHD). The prevelance of RHD in Yemen has been found to be 3.6/1000 population6. Despite a sharp decline in RHD worldwide over the last 30 years7, valvular regurgitation is still a frequent finding8. Functional mitral regurgitation occurs with a structurally normal valve as a complication of systolic left ventricular dysfunction. Hypertensive heart disease was the main cause of functional MR in our study and this occurs mainly due to left ventricular geometric changes and left ventricular dysfunction. Yiu et al9 concluded that the presence and degree of functional MR complicating left ventricular dysfunction is unrelated to the severity of left ventricular dysfunction. Local LV remodeling (apical and posterior displacement of papillary muscles) leads to excess valvular tenting independent of global LV remodeling. These determinants of functional MR warrant consideration for specific approaches to the treatment of functional MR complicating left ventricular dysfunction.
 

Conclusion


   
       Functional mitral regurgitation secondary to hypertension was quite high in this study and RHD was still the leading cause of organic MR in the Yemeni population. Nationwide campaigns against hypertension and rheumatic fever/RHD would be the most cost effective preventive measures to decrease MR in a country like Yemen.¨


References:


1. Mohamed YAK & El-Sorori AW: Pattern of Medical Admissions to the Al-Thawra Teaching Hospital, Sana’a, Yemen in 1991 and comparison with Non-Yemeni studies. JHGID April 1995 - Vol.3.No. 4.

2. Recusani F, Bargiggia GS, Yoganathan AP, Raisaro A, Valdes-Cruz LM, Sung HW, Bertucci C, Gallati M, Moises VA, Simpson IA, Tronconi L, Sahn DJ. A new method for quantification of regurgitant flow rate using color Doppler flow imaging of the flow convergence region proximal to a discrete orifice. Circulation 1991;83:594-604.

3. Sahn DJ, Maciel BC. Physiological valvular regurgitation. Doppler echocardiography and the potential for iatrogenic heart disease. Circulation, 1988;78:1075-1077.

4. Yoshida K, Yoshikawa J, Shakudo M, et al. Color Doppler evaluation of valvular regurgitation in normal subjects. Circulation, 1988;78:840-847.

5. Rahko PS. Prevalence of regurgitant murmurs in patients with valvular regurgitation detected by Doppler echocardiography. Ann Intern Med. 1989;111:466-472.

6. A N Munibari, T M Nasher, S A Ismail, A Mukhtar, Department of Internal Medicine, Faculty of Medicine and Health Sciences Sana’a University: Prevalence of Rheumatic Fever And Rheumatic Heart Disease in Yemen. Asian Cardiovasc Thorac Ann 2006;9:41-44.

7. Stollerman GH. Rheumatic fever and other rheumatic disease of the heart. In: Braunwald E, ed. Heart Disease: A Textbook of Cardiovascular Medicine. 4th ed. Philadelphia: WB Saunders, 1992:1721.
 
8. Klein AL, Burstow DJ, Tajik AJ, et al. Age-related prevalence of valvular regurgitation in normal subjects: a comprehensive color flow examination of 118 volunteers. J Am Soc Echocardiogr. 1990;3:54-63.

9. Siu F. Yiu, MD; Maurice Enriquez-Sarano, MD; Christophe Tribouilloy, MD; James B. Seward, MD; A. Jamil Tajik, MD: Determinants of the Degree of Functional Mitral Regurgitation in Patients With Systolic Left Ventricular Dysfunction. A Quantitative Clinical Study. Circulation, 2000;102:1400-1406.
 

                                               

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