75Case 16 Aneurysm of Aorta

Table 16.2: Clinical features of Marfan’s syndrome

Skeletal Cardiac Others

Tall stature Aortic dilatation Dislocation of lens Joint hypermobility Aortic aneurysm High-arched palate Arm-span > height Aortic dissection Crowded dentition Long digits (arachnodactyly) Aortic regurgitation Pectus carinatum Scoliosis and sternal deformity Mitral valve prolapse Inguinal hernia

Cardiovascular complications are initiated by cystic medial necrosis of the ascending aorta. There is dilatation of the aortic root with aortic valve insufficiency and left ventricular volume overload (Fig. 16.2). Catastrophic dissection involving the proximal aorta is a serious and potentially lethal complication. Mitral valve prolapse is sometimes associated.

Figure 16.2: ECHO showing an aneurysmal aorta with jet of aortic regurgitation

abnormalities of the skeletal system are observed. The typical body habitus is a tall and slender figure with long tapering fingers and increased joint mobility.

The pubis-to-heel measurement exceeds the crown-to-pubis length. Associated abnormalities include a high-arched palate, pectus carinatum, dislocated ocular lenses (ectopia lentis) and presence of inguinal hernias (Table 16.2).

Although syphilitic aortitis is now distinctly rare, Takayasu’s aorto-arteritis still afflicts young women in south Asia. It causes aneurysmal aortic dilatation and stenosis of the major branches emerging from the aorta. Blood pressure in the two arms may be different due to narrowing of subclavian artery on one side. On the other hand, hypertension may be present in the lower limbs due to reno-vascular stenosis. Therefore, Takayasu’s aorto-arteritis is also designated as

“reverse coarctation”.

76 Section 5 Aortic Diseases

Table 16.3: Indications for aortic aneurysm surgery

•  Severe dilatation more than 50 mm

•  Rapid aneurysm growth > 10 mm/year

•  Dissection of the proximal aorta

•  Severe aortic regurgitation

MANAGEMENT ISSUES

The medical management of an aortic aneurysm depends upon its size, the blood pressure and the presence or absence of aortic dissection. If the aneurysm is small, stable in size and there is no dissection, it suffices to adequately control the blood pressure. A drug with negative ionotropic effect such as a beta-blocker is preferable, since it reduces the shearing force on the aorta. The patient is counselled to avoid strenuous and burst activity like weight-lifting. Follow-up echo is recommended every 6 to 12 months, to assess the size of aneurysm and degree of aortic regurgitation.

Surgical intervention is considered if the aneurysm is growing in size on serial imaging, there is evidence of impending rupture or dissection, or if the aortic regurgitation is severe (Table 16.3). The affected segment of the ascending aorta is resected and replaced with a prosthetic graft.

RECENT ADVANCES

Newer imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) have obviated the need for aortography, in the evaluation of aortic aneurysms. Serial imaging can identify an expanding size, impending rupture and an associated dissection.

C A S E

17 Dissection

of Aorta

CASE PRESENTATION

A 64-year old woman presented to the emergency department with sudden onset of severe chest pain, one hour back. The chest pain was central in location and it peaked instantly. The pain was also felt over the back between her scapulae, but did not radiate to the arms or neck. There was no history of suffocation, choking, palpitation or syncope and she had never experienced such chest pain before. She had a history of hypertension for which she had been prescribed multiple drugs.

However, she was irregular with her medication and often skipped her doses. As a result, her BP hovered around 150/100 mm Hg on most occasions. She was not a diabetic but was advised to take atorvastatin for her elevated LDL-cholesterol. She did not consume alcohol, but smoked a pack of cigarettes per day for the last 40 years. Although distressed by severe chest pain, she managed to tell the attending doctor that the grip of her left hand felt weak since one hour.

On examination, she was clearly distressed but not dyspneic or diaphoretic. Pulse rate was 104 beats/min., with a BP of 174/106 mm Hg in her right arm. All peripheral pulses in the lower extremities were palpable, but a bruit was audible over the right carotid artery. The JVP was not raised and there was no pitting edema around the ankles. The apex beat was heaving in nature and slightly displaced outwards towards the axilla. The S₁ was normal and A₂ was loud, but there was no gallop sound. A faint early-diastolic murmur was audible along the left sternal border.

CLINICAL DISCUSSION

In an elderly patient, the most frequent but by no means the sole cause of excruciating chest pain is myocardial infarction. Other causes of severe chest pain are pulmonary embolism and spontaneous pneumothorax. The pain of pleuro-pericarditis, oesophagitis or costo-chondritis is seldom excruciating.

Acute aortic dissection is an uncommon but potentially fatal cause of severe chest pain that merits a high index of clinical suspicion.

The ECG showed sinus tachycardia but no S-T segment shift and the troponin-T test was negative on admission. X-ray chest findings were mild cardio megaly with a left ventricular contour and slight mediastinal widening due to aortic root dilatation. There was no basal atelactasis, pleural effusion or pneumothorax.

ECHO revealed dilatation of the aortic root, with a false lumen cleaving the

78 Section 5 Aortic Diseases

Table 17.1: Causes of aortic dissection

•  Marfan’s syndrome 

•  Coarctation of aorta 

•  Accelerated hypertension 

•  Hypertension in pregnancy 

•  Trauma; accidental or surgical 

Acute myocardial infarction is an unlikely possibility in this case. The pain of myocardial infarction does not reach its maximum intensity instantly, but builds up gradually. Moreover, the radiation and accompaniments that are typical of the pain of myocardial infarction, were absent in this case. The ECG did not show S-T segment elevation and the troponin test was negative. On ECHO, cleavage of aortic wall and presence of aortic regurgitation are not typical features of acute myocardial infarction.

Figure 17.1:  ECHO showing cleavage of the anterior aortic wall  with intimal flap between true and false lumens

anterior aortic wall and having a blind end. An intimal flap separated the false lumen from the true aortic lumen (Fig. 17.1). On colour Doppler, a mosaic jet was observed in the left ventricular outflow tract, along the septum. There was no pericardial effusion. These findings were consistent with the diagnosis of acute dissection of the aorta.

Dissection of aorta is often due to accelerated hypertension and may complicate hypertension in pregnancy. Other causes are aortic coarctation and Marfan’s syndrome (Table 17.1). Aortic dissection cleaves the media of the aortic wall, with the adventitia and outer media forming the outer wall and the inner media and intima forming the inner wall. The false lumen produced by cleavage has a blind distal end while the proximal end communicates with the true lumen at the site of aortic tear. The intimal flap oscillates between the true and false lumens (Table 17.2). Other reasons for deformity of the anterior aortic wall are aortic root abscess in infective endocarditis and an aneurysm of the sinus of Valsalva.

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