Early assessment and management

In this study, 26% of the patients were diagnosed during pregnancy and several of the cases resulting in maternal death presented late. These findings support the notion that management of women with RHD should ideally begin before conception or very early in pregnancy with a careful assessment and risk stratification as shown in table 1. The value of obtaining a careful history has been shown in this study and others,2 who found prior cardiovascular events to be a powerful predictor of pregnancy-associated complications. A 12-lead ECG is helpful for the assessment of arrythmias, an echocardiogram for evaluation of cardiac function, severity of valvular stenotic and regurgitant lesions, the presence of pulmonary hypertension and suitability for mitral valve (MV) balloon valvuloplasty in patients with mitral stenosis (MS). Exercise test should be used to obtain additional objective information regarding exercise capacity. Exercise echo or cardiopulmonary exercise test if available, can provide further assessment of functional capacity, especially in sedentary women who claim to be asymptomatic. Because of the limitations of various non-invasive methods in the assessment of severity of valvular disease,1 invasive haemodynamic assessment may be considered. In addition, in anticipation to pregnancy, drugs with potential harm to the fetus should be discontinued.

Baghel et al 3 identified a number of important predictors of risk for adverse cardiac outcome in women with rheumatic RHD including prior cardiovascular events, pulmonary hypertension and moderate and severe MS. It should be noted that these risk predictors are also indications for interventions.4 Patients with these conditions should ideally undergo appropriate catheter based or surgical interventions prior to pregnancy and those who are already pregnant require an intense follow-up.

About two-thirds of the patients with MV disease in this study had either moderate or severe mitral regurgitation (MR). Although MR is better tolerated than MS because of the unloading effect of pregnancy,5 women meeting usual indications for mitral valve replacement (MVR) should undergo such a procedure prior to pregnancy and be re-evaluated after the procedure. At the same time, premature, prophylactic MVR before pregnancy is not necessary because pregnancy after valve replacement may be less desirable, especially in the patient with mechanical prosthetic heart valve.

Prevention of complications during pregnancy

About 30% of the patients in the study by Baghel et al 3 were classified at baseline in the modified WHO risk categories III and IV, where pregnancy should be discouraged prior to conception and early termination should be discussed in women who are already pregnant. Pregnant patients with risk criteria identified in this study should be followed closely during pregnancy. A regimen of biweekly follow-up visits until 30 weeks gestation followed by weekly visits until delivery is usually effective in early detection of new or worsening of symptoms. BNP levels, and haemodynamics determined by echocardiography and if needed, by right heart catheterisation are helpful to confirm relation between symptoms and haemodynamic deterioration. Optimal management of patients with MS should aim at reducing heart rate and left atrial pressure with beta-blockers. Percutaneous mitral balloon commissurotomy (PMBC) should be performed in increasingly symptomatic patients who do not respond to medical therapy and a surgery in patients not suitable for PMBC. Because of the high risk of fetal loss associated with cardiac surgery during pregnancy preterm delivery and simultaneous cardiac repair may be considered in unstable women who cannot be stabilised and who are past 28 weeks of gestation. Medical therapy for high-risk women with severe MR (heart failure, left ventricular (LV) dysfunction, pulmonary hypertension) include diuretics, digoxin and vasodilators and in severe cases MVR during pregnancy or immediately after the delivery.

About a quarter of the patients in the study by Baghel et al 3 had involvement of the aortic valve which is in general better tolerated than MV disease during pregnancy.6 Severely symptomatic patients with aortic stenosis, however, may benefit from balloon valvuloplasty as a bridge for surgery after the delivery to allow a safe continuation of pregnancy and avoid severe prematurity. Aortic regurgitation with LV dysfunction and heart failure may be treated with diuretics and vasodilators.

Prevention of complications during labour and delivery

Timing and mode of delivery as well as the form of anaesthesia can have a significant impact on the risk of both maternal and fetal complications and should be decided on jointly by the obstetrician, cardiologist, neonatologist and obstetric anaesthesiologist with a goal of protecting the mother and also attempting to avoid extreme prematurity. Caesarean section delivery is often preferred by clinicians in patients with cardiac disease,5 6 but is associated with a higher risk of early and late complications. Over 80% of the patient in the present study were delivered vaginally. This high incidence of vaginal delivery supports the recommendations to use a surgical delivery only in cases of fetal or maternal instability.1 In most cases, vaginal delivery with appropriate anaesthesia and shortening of the second stage is safe. Regional anaesthesia is usually preferred. Invasive haemodynamic evaluation should be considered in symptomatic patients with severe disease for optimisation prior to delivery and monitoring during the delivery and early post partum.

Prevention of complications postdelivery

Most complications after the delivery are related to an increase in preload due to an increase in venous return to the heart as a result of cessation of the inferior vena cava compression by the fetus, ‘autotransfusion’ of blood from the contracting uterus and movement of fluid from the lower limbs into the venous circulation. At the same time, there is an increase in afterload to the left ventricle due to the loss of the low resistance placenta. These haemodynamic changes can lead to heart failure and arrythmias. Use of diuretics after the delivery and continued monitoring are important.