Abstract:
Background: Pulmonary Hypertension in mitral valvular heart disease leads to various adverse outcome following surgical treatment of this condition. In majority of the patients this Pulmonary Hypertension is reversible following surgery. The objective of this study is to assess the outcome of changes in Severe Pulmonary Hypertension after Mitral Valve Replacement during the follow up with postop ECHO.
Patients and methods: In all our 265 patients who underwent Mitral Valve Replacement Surgery (MVR) for Mitral valvular heart disease with pulmonary hypertension, females 111/195(56.9%) outnumbered the males in this study. 195 among 265 cases had severe PHT. MVR was done with cardiopulmonary bypass using St Jude’s medical valve.
Results : Despite the high operative mortality in most series of MVR in patients with severe PHT, a striking improvement in survival was noted in the study with 5.3% mortality rate.A sudden drop of PHT is not observed in our study. The fall was found to be gradual and significant over follow up and the maximum reduction was at 1-3 months post operatively.
Conclusion : It is concluded that MVR reduces PHT in a gradual way and the mortality rate is also minimum in severe PHT patients. MVR thereby is an effective invasive procedure for the management of patients with severe mitral valve disease and PHT.
Keywords: Severe Pulmonary Hypertension, mitral valvular disease, mitral valve replacement, Pulmonary artery pressure, Rheumatic Heart Disease
INTRODUCTION :
Pulmonary Hypertension (PHT) is an increase in blood pressure in the Pulmonary artery, Pulmonary vein, or pulmonary capillaries, together known as the Lung Vasculature, leading to shortness of breath, dizziness, fainting, and others Symptoms, all of which are exacerbated by exertion. Pulmonary Hypertension can be a severe disease with a markedly decreased exercise tolerance and heart failure[1].Patients with Rheumatic Heart Disease develop Pulmonary Hypertension due to various reasons and prime cause among them will be the retrograde transmission of Left atrial hypertension which gets transmitted to the Pulmonary arteries. Pulmonary venous pressure also is transmitted to Pulmonary arteries. Pulmonary Arteriolar constriction, morphological changes in Pulmonary Vasculature and Interstitial Oedema can also lead to the development of Pulmonary Hypertension [1].
PHT was initially classified by World Health Organisation (WHO) as, Group I - Pulmonary Arterial hypertension (PAH), WHO Group II - Pulmonary Hypertension associated with left heart disease, WHO Group III - Pulmonary Hypertension associated with lung diseases and/or Hypoxemia and WHO Group IV - Pulmonary Hypertension due to chronic thrombotic and/or embolic disease by the Venice 2003 revised classification system [2].
Heath Edwards grading system classified PH into six grades based on severity and pathophysiology of the disease. Usually Pulmonary Hypertension grade 3 and below are reversible and can be taken up for surgery with better results. Pulmonary Hypertension grade 4 and above has significant contribution for postoperative morbidity and mortality [3].
Catheterization studies are not done routinely as echocardiogram has emerged as an effective tool to identify Pulmonary Hypertension and classify accordingly.
Pulmonary Hypertension in mitral valvular heart disease leads to various adverse outcomes following surgical treatment of this condition. Pulmonary Hypertension is said to complicate about 70% of the patients affected by this disease. Mitral valvular heart disease includes Mitral stenosis (MS) which refers to narrowing of the mitral valve orifice and Mitral valvular Regurgitation (MR) . It is usually caused by rheumatic heart disease [4].
Pathophysiology of Pulmonary Hypertension in Mitral Valvular heart disease in both Rheumatic Mitral Stenosis and Regurgitation can be described as follows,
Elevated LA pressureElevated Pulmonary venous pressureTransmitted pulmonary venous hypertension to arteriesVasoconstriction of Pulmonary arteriolesPulmonary Artery HypertensionRight ventricular dilatationTricuspid RegurgitationRight Atrial enlargementCongestive cardiac failure. Pulmonary Hypertension greatly influences the natural course of the disease process, treatment response and also the post intervention prognosis [1, 4&7].
Features indicating severity of disease in mitral valvular lesions complicated by pulmonary hypertension includes, Severe Subvalvular Pathology, Small Mitral Valve Area, Higher Transvalvular gradient, Higher Pulmonary valve resistance, Higher NYHA symptoms, Thickened non pliable valves, Higher Wilkins score and Higher incidence of Atrial Fibrillation[1,4].
Treatment options can be medical, interventional or surgical. Rate control drugs like Betablocker and Calcium channel blockers help in reducing the transmitral gradient and hence the PHT. Digoxin is usually started for the failing heart and RV dysfunction which has to pump blood against severe PHT [6].
In interventional method for isolated MS and PHT, Balloon Mitral Valvotomy (BMV) is done in various centres .Balloon Mitral Valvotomy can be attempted only if the valves are pliable and the Wilkins score is favorable[6].There are many concerns before proceeding to BMV like the less tolerance to the stress of the procedure, difficulty in negotiating the septum in large right sided chambers, Tight Mitral Stenosis and fear of tearing the mitral valve and creating Mitral Regurgitation[6].
Various options are open for surgical management of Mitral Valvular heart disease like Mitral valve replacement (MVR), Closed Mitral Commisurotomy and Open Mitral Valvotomy. Mitral Valve Replacement may be done with either mechanical prosthetic valve or Bioprosthetic Valve , Autologous transfer of Pulmonary valve (ROSS II PROCEDURE) has also been done for this condition[6] .Pulmonary Hypertension regresses after the transmitral gradient gets reduced following surgery[8].
The objective of this study is to analyze the reduction in Pulmonary Hypertension following mitral valve replacement during patient follow up post surgically.An attempt of a prospective study to analyze the facts is made and the results are tabulated and compared to the national and international views on the same parameter of this common disease. The results obtained from the data collection were tabulated and analyzed.