Aortitis And Aortic Insufficiency As Syphilitic Affection Of The Cardiovascular System

Cardiovascular syphilis, one of the few easily preventable forms of heart disease has become uncommon since the introduction of effective antisyphilitic treatment. The manifestations of syphilitic cardiovascular disease are seen in the tertiary stage. These include aortitis, aortic insufficiency, aneurysm or aorta, coronary ostial stenosis, gumma of the myocardium and syphilitic endarteritis.

Aortitis

This may occur in 70-80% of the untreated cases, if allowed to progress. The causative organism, Trepanema Pallidum, invades the adventitial layer of the aorta soon after the primary infection, spreading later to the media through the lymphatics surrounding the vasa vasorum after several years. Endarteritis of vasa vasorum results in necrosis of the elastic and connective tissues of the media. At first, the intima over-lying the areas of medial necrosis becomes thickened. Later it becomes pitted and scarred to resemble the bark of a tree. Treponema Pallidum may survive in the aortic wall for 20 to 30 years.

Inflammatory changes are most frequent and severe in the ascending aorta and they are least in the distal parts. If left untreated, 10% of subjects with syphilis may develop aortic regurgitation or coronary ostial narrowing due to involvement of the proximal aorta. The longer the delay in treatment, the greated is the likelihood of lethal complications.

Clinical features

The patient may complain of a burning type of retrosternal pain or true angina pain felt over the retrosternal region. Examination may reveal aortic systolic murmur, and a ringing second sound.

Diagnosis

Criteria for diagnosis of syphilitic aortitis are:

1. Dilatation of the ascending aorta,
2. A ringing loud aortic component of second heart sound in a normotensive subject without evidence of atherosclerosis and
3. A systolic murmur in the aortic area.

Calcification of the anterolaterla wall of aorta may be seen on fluoroscopy (Calcification due to atherosclerosis is more frequently along the medial border of the ascending aorta and arch). Dilatation of aorta is detectable by achocardiography.

Aortic valvular regurgitation, the most frequent complication of syphilitic aortitis, results from dilatation of aortic valve ring and improper apposition of the leaflets due to mesoaortitis of proximal aorta. The aortic valve cusps may be thickened and rolled up at the edges without calcification or stenosis. Left ventricular dilatation and hypertrophy may occur. In addition, coronary osteal narrowing and aneurysm of aorta may coexist.

Clinical features

Males are affected four times more frequently than females. Around 10-25 years may elapse between the primary lesion and the onset of AR. When the AR is significant, cardiac sings and all the peripheral signs of free aortic regurgitation may be detectable. The high-pitched decrescendo early diastolic murmur of aortic regurgitation is best appreciated with the diaphragm of the stethoscope firmly applied in the second right intercostals space with the patient leadning forward and holding his breath in expiration. As the AR is the result of dilatation of the aortic root, the murmur is often better heard in the right sterna border than the left. A hyper-dynamic apical impulse, soft first heart sound, a ventricular diastolic gallop and mid-diastolic rumble at the apex (Austin Flint murmur) constitute the other physical signs.

Echocardiography is a very useful diagnostic investigation in AR. Cardiac catherisation and angiography may be required for full assessment.

A history of syphilitic infection, evidence of syphilis elsewhere in the body, psotive serological tests for syphilis and the presence of murmur of AR are pointers to the diagnosis.

Prognosis

Once heart failure sets in, average life expectancy is only 3 years. It is even less in the presence of angina due to osteal stenosis.

Treatment

Curtailment of physical activity is of paramount importance. Measures to control heart failure are employed and penicillin therapy is instituted as required for tertiary syphilis. Jarish-Herxheimer reaction may occur rarely leading to further diminution of coronary blood flow.

Surgical treatment consists of replacement of aortic valve to correct AR and coronary artery bypass grafting when there is coronary osteal stenosis.