Clinical Features, Course, Prognosis And Management Of Aortic Stenosis
Stenosis In the Aorta
Course, Prognosis And Treatment
The symptoms are not very reliable in assessing the severity of aortic stenosis, since even significant aortic stenosis may remain asymptomatic for long periods. Sudden death may occur as a result of fatal arrhythmias even in asymptomatic subjects. Mild aortic stenosis may not produce symptoms. The three most important presentations of significant aortic stenosis are angina pectoris, syncope and left ventricular failure.
Other symptoms include palpitation, exertional fatigue and visual field defects probably secondary to minute calcific emboli from the aortic valves.
The characteristic physical findings develop in significant aortic stenosis. The pulse is described as anacrotic. This is a small volume and slow rising pulse. The pulse pressure is usually less than 30 mm of mercury because of depression of the systolic pressure. In the elderly subjects, even with significant aortic stenosis, the systolic pressure may occasionally reach 160 mm or more. Consequently, in such patients, the severity of aortic stenosis cannot be predicted from the amplitude of pulse pressure. Apex beat is characteristically forcible and sustained (heaving). There may be a systolic thrill, best felt in the second right intercostals space, or along the left sterna border and very rarely over the apical impulse also.
Auscultation reveals a harsh grunting ejection systolic murmur which is conducted to the carotids and well heard over the apical impulse as well. The ejection systolic murmur corresponds to the period of ejection, i.e, it starts with the opening of the aortic valves and is over before the second sound is heard. The murmur becomes louder with the phase of maximal ejection and towards the latter part of systole, the murmur comes down. When the stenosis is severe, the murmur is longer, louder and its peak is reached later in systole. The aortic component of the second heart sound is delayed and soft. The second heart soundmay be split paradoxically.
Electrocardiogram is normal in mild cases. In significant aortic stenosis, ECG shows left ventricular hypertrophy as well as left atrial overload pattern. The ECG pattern of left ventricular hypertrophy correlates with the severity and prognosis of aortic stenosis.
Radiological findings: In aortic stenosis, the heart is not usually enlarged. The concentric hypertrophy is manifested in chest X-ray as a convex bulge of the lower third of the left border of the heart. The ascending aorta is dilated. Post-stenotic dilation does not have any relation with the severity of aortic stenosis.
Echocardiography: It is helpful in visualizing the nature o the aortic valve and the severity of the stenosis. Cardiac catheterization and angiography help in the accurate determination of the severity of aortic stenosis. Intra-cardiac pressure studies reveal the gradient between left ventricular pressure and aortic pressure.
Aortic Valve Stenosis
Course, Prognosis And Management
Course and prognosis: Mild cases do not progress and may remain asymptomatic. However, the course of aortic stenosis cannot be predicted with confidence because of the variability in its progression due to the deposition of calcium.
Grave symptoms may develop abruptly in an asymptomatic patient. In 15-20% sudden cardiac death may occur. Occurrence of angina pectoris, syncope or left ventricular failure is associated with a life expectancy of less than five years. It is important to recognize this stage. Once congestive heart failure sets in, the course is rapidly downhill with death occurring in less than two years.
Management: Once significant symptoms are recognized, the treatment involves aortic valve replacement. In children, surgery is advisable for severe aortic stenosis, even though it is asymptomatic. In them aortic valvotomy is advised. In elderly individuals, preoperative coronary arteriography is undertaken to find out the existence of obstructive coronary artery disease. In such cases, aortic valve replacement is don along with coronary heart failure is controlled by medical treatment before surgery is undertaken.
© 2014 Funom Theophilus Makama