Tricuspid Stenosis – narrowing of the tricuspid valve

Tricuspid Stenosis – narrowing of the tricuspid valve

Tricuspid Stenosis – narrowing of the tricuspid valve: Tricuspid valve, named so because it has three leaflets or cusps, prevents backflow of blood from the right ventricle when it contracts, to the right atrium. Tricuspid stenosis (narrowing of the tricuspid valve) is much rarer, compared to mitral stenosis (narrowing of the mitral valve, which prevents backflow of blood from left ventricle to the left atrium). Rheumatic (as a sequel of rheumatic fever) tricuspid stenosis is almost invariably associated with mitral stenosis. Carcinoid heart disease (seen in carcinoid syndrome due to a carcinoid tumor which has spread to the liver, causing serotonin secreted by the tumor to damage the right sided heart valves) is another important cause of tricuspid stenosis. Tricuspid stenosis can also occur as a part of Ebstein’s anomaly of the tricuspid valve.

Tricuspid stenosis leads to right atrial dilatation and a prominent a wave in the jugular venous pulse (pulsation in the veins at the root of the neck which drain deoxygenated blood from the head and neck). Right atrial dilatation can stretch open the foramen ovale (an oval opening in the center of the wall separating the left and right atrium, seen in fetal life, which normally closes soon after birth) and lead to right to left shunt. Right to left atrial shunting of blood would mean that deoxygenated blood reaches left atrium from the right atrium. This is further ejected into the circulation by the left ventricle to cause a lowering of the oxygen saturation in the blood reaching the whole body. Since tricuspid valve is the largest of the cardiac valves, even a pressure gradient as low as 2 mm Hg across it can indicate significant tricuspid stenosis.

ECG (electrocardiogram) shows right atrial overload in the form of peaked P waves in lead II (a combination of electrodes kept across right arm and left leg) and a tall initial peak in lead V1 (an electrode kept on the chest). X-ray chest may show the right atrial enlargement as a rightward shift of the right heart border or an increase in the vertical height of the right heart border. Tricuspid stenosis produces a mid diastolic murmur (an additional murmuring heart sound after the second heart sound and before the first heart sound, when the heart is relaxing after a contraction) in the tricuspid area (lower part of chest, just to the left of sternum or breastbone) which increases with inspiration (breathing in), like all right sided murmurs. Severe tricuspid stenosis produces presystolic hepatic pulsations (pulsation of the liver just before the onset of contraction of the heart) due to vigorous atrial contraction against a stenotic (narrowed) tricuspid valve.

Tricuspid stenosis can be treated by balloon tricuspid valvotomy (opening of the narrowed tricuspid valve with a balloon catheter) with good results. In tricuspid valvotomy, a balloon mounted at the tip of a small tube (balloon catheter) is introduced through a small opening in the groin under local anaesthesia. The tube with balloon is guided under X-ray fluoroscopy to the right side of the heart where it is positioned across the tricuspid valve, which is usually located in the midline overlapping the spine in the lower part of the heart shadow on X-ray. Once the position is confirmed the balloon is inflated to relieve the narrowing of the tricuspid valve. Pressure gradient across the valve is measured before and after the procedure to ensure a good result. Repeated inflations can be done if the drop in pressure gradient is not satisfactory, with care being taken not to overinflate the valve and producing a tear in the leaflets which can cause a leak in the valve.