Right Ventricular Function After Mitral Valve Replacement in Rheumatic Heart Disease Patients With Pulmonary Hypertension: Short Term Follow up

In 1994, it was estimated that 12 million individuals had RF and RHD worldwide , and at least 3 million had congestive heart failure (CHF) that required repeated hospital admissions. A large section of the individuals with CHF required cardiac valve surgery within 5-10 years . The mortality rate for RHD varied from 0.5 per 100 000 population in Denmark, to 8.2 per 100 000 population in China , and the estimated annual number of deaths from RHD for 2000 was 332000 worldwide . The mortality rate per 100 000 population varied from 1.8 in the WHO Region of the Americas, to 7.6 in WHO South-East Asia Region. The disability-adjusted life years (DALYs)1 lost to RHD ranged from 27.4 DALYs per 100 000 population in the WHO Region of the Americas, to 173.4 per 100 000 population in the WHO South-East Asia Region. An estimated 6.6 million DALYs are lost per year worldwide.

THE PATHOLOGY OF RHEUMATIC MITRAL VALVE DISEASE Rheumatic mitral valves shows a different set of lesions by comparison with degenerative valves, because of the characteristic inflammatory process, which results in thickening of the leaflets and other components of the mitral valve apparatus, of variable degrees, and distorts and impairs the movements of the valve. So, the disease appears here in two forms - stenosis and regurgitation, or a combination of both.

In the case of valve regurge, the most frequent lesion is prolapse of the anterior leaflet, which is present in more than 90% of young patients and is most often caused by elongated chordae to its central and medial areas (A2 and A3). In contrast to degenerative disease, posterior leaflet prolapse is practically not found, except in cases with ruptured chordae due to infective endocarditis. On the contrary, this leaflet is often shortened in its width, sometimes resumed to a very narrow and thick strip of tissue. In more complicated cases, the chordae may be thick and retracted, as may also be the papillary muscles, and the commissures may be fused in varying degrees. Often, the leaflets and subvalvular apparatus are a continuous mass of fibrous tissue. Lastly, the annulus is dilated in 95% of the patients. It is widely accepted that dilatation occurs essentially in the posterior segment of the annulus, although there is some evidence that it may also occur in the anterior segment, especially in dilated cardiomyopathy.

Pulmonary hypertension and valvular heart disease Valvular Heart Disease VHD is a common etiology of pulmonary hypertension, which may result from many mechanisms as an increase in pulmonary vascular resistance, pulmonary blood flow, or pulmonary venous pressure. The chronic rise in pulmonary arterial pressure (PAP) often leads to right ventricular (RV) pressure overload and subsequent RV failure. When present, PH is a marker of poor outcome in VHD. Assessment of the presence and severity of Pulmonary hypertension thus has an important role in the risk stratification and therapeutic management of VHD.

The sure diagnosis of PH related to VHD is based on the following criteria: mean PAP 25 mm Hg together with an abnormally high pulmonary capillary wedge pressure (PCWP) >15 mm Hg or left ventricular (LV) end-diastolic pressure >18 mm Hg in the context of significant VHD. When pulmonary venous congestion is the main determinant of PH, PH is named isolated post-capillary PH or pulmonary venous hypertension.