that flow forward through the mitral valve and aortic valve during a cardiac cycle. methods that have been used to assess the regurgitant fraction in mitral regurgitation include echocardiography, cardiac catheterization, fast ct scan, and cardiac mri. the echocardiographic technique to measure the regurgitant fraction is to determine the forward flow through the mitral valve (from the left atrium to the left ventricle) during ventricular diastole, and comparing it with the flow out of the left ventricle through the aortic valve in ventricular systole. this method assumes that the aortic valve does not have aortic insufficiency. another way to quantify the degree of mr is to determine the area of the regurgitant flow at the level of the valve. this is known as the regurgitant orifice area and correlates with the size of the defect in the mitral valve. one particular echocardiographic technique used to measure the orifice area is measurement of the proximal isovelocity surface area (pisa). the flaw of using pisa to determine the mitral valve regurgitant orifice area is that it measures the flow at one moment in time in the cardiac cycle, which may not reflect the average performance of the regurgitant jet. the pisa method for quantification of mitral regurgitation determination of the degree of mitral regurgitation grade degree of mitral regurgitation regurgitant fraction regurgitant orifice area 1 mild< 20 percent 2 moderate20 - 40 percent 3 moderate to severe40 - 60 percent 4 severe> 60 percent> 0.4 cm2 treatment the treatment of mr depends on the acuteness of the disease and whether there are associated signs of hemodynamic compromise. in general, medical therapy is non-curative and is used for mild-to-moderate regurgitation or in patients unable to tolerate surgery. in acute mr secondary to a mechanical defect in the heart (i.e., rupture of a papillary muscle or chordae tendineae), the treatment of choice is mitral valve surgery. if the patient is hypotensive prior to the surgical procedure, an intra-aortic balloon pump may be placed in order to improve perfusion of the organs and to decrease the degree of mr. medicine if the individual with acute mr is normotensive, vasodilators may be of use to decrease the afterload seen by the left ventricle and thereby decrease the regurgitant fraction. the vasodilator most commonly used is nitroprusside. individuals with chronic mr can be treated with vasodilators as well to decrease afterload. in the chronic state, the most commonly used agents are ace inhibitors and hydralazine. studies have shown that the use of ace inhibitors and hydralazine can delay surgical treatment of mr. the current guidelines for treatment of mr limit the use of vasodilators to individuals with hypertension, however. any hypertension is treated aggressively, e.g. by diuretics and a low sodium diet. in both hypertensive and normotensive cases, digoxin and antiarrhythmics are also indicated. also, chronic anticoagulation is given where there is concomitant mitral valve prolapse or atrial fibrillation. surgery surgery is curative of mitral valve regurgitation. there are two surgical options for the treatment of mr: mitral valve replacement and mitral valve repair. mitral valve repair is preferred to mitral valve replacement where a repair is feasible as bioprosthetic replacement valves have a limited lifespan of 10 to 15 years, whereas synthetic replacement valves require ongoing use of blood thinners to reduce the risk of stroke. there are two general categories of approaches to mitral valve repair: resection of the prolapsed valvular segment (sometimes referred to as the "carpentier" approach) and installation of artificial chordae to "anchor" the prolapsed segment to the papillary muscle (sometimes referred to as the "david" approach). with the resection approach, any prolapsing tissue is resected, in effect removing the hole through which the blood is leaking. in the artificial chordae approach, eptfe (expanded polytetrafluoroethylene, or gore-tex) sutures are used to replace the broken or stretched chordae tendonae, bringing the natural tissue back into the physiological position, thus restoring the natural anatomy of the valve. with both techniques, an annuloplasty ring is typically secured to the annulus, or opening of the mitral valve, to provide additional structural support. in some cases, the "double orifice" (or 'alfieri') technique for mitral valve repair, the opening of the mitral valve is sewn closed in the middle, leaving the two ends still able to open. this ensures that the mitral valve closes when the left ventricle pumps blood, yet allows the mitral valve to open at the two ends to fill the left ventricle with blood before it pumps. in general, mitral valve surgery requires "open-heart" surgery in which the heart is arrested and the patient is placed on a heart-lung machine (cardiopulmonary bypass). this allows the complex surgery to proceed in a still environment. due to the physiological stress associated with open-heart surgery, elderly and very sick patients may be subject to increased risk, and may not be candidates for this type of surgery. as a consequence, there are attempts to identify means of correcting mr on a beating heart. the alfieri technique for instance, has been replicated using a percutaneous catheter technique, which installs a "mitraclip" device to hold the middle of the mitral valve closed. indications for surgery for chronic mr include signs of left ventricular dysfunction with ejection fraction less than 60%, severe pulmonary hypertension with pulmonary artery systolic pressure greater than 50 mmhg at rest or 60 mmhg during activity, and new-onset atrial fibrillation. indications for surgery for chronic mr symptoms lv ef lvesd nyha ii> 30 percent< 55 mm nyha iii-iv< 30 percent> 55 mm asymptomatic30 - 60 percent≥ 40 mm asymptomatic with pulmonary hypertensionlv ef > 60 percent and pulmonary artery systolic pressure >50-60 mmhg asymptomatic and chance for a repair without residual mr is >90%> 60 percent< 40 mm epidemiology significant mitral valve regurgitation has a prevalence of approximately 2% of the population, affecting males and females equally. it is one of the two most common valvular heart diseases in the elderly, and the commonest type of valvular heart disease in low and middle income countries. in a study of 595 male elite football players aged 18–38 and 47 sedentary non-athletes, mitral regurgitation was found in 20% football players and 15% in control group. football players with mitral regurgitation were found to have larger mitral annulus diameter compared to athletes without regurgitation, and left atrium diameter was larger in athletes with mr.