The cardiovascular diseases

THE AORTIC DISSECTION

- Definition
- A few explanations
- The Symptoms
- How to make the diagnosis?
- The Causes
- Prognosis
- Treatment
- Conclusion

HOW TO MAKE THE DIAGNOSIS?

1 - By the clinical exam achieved by the physician:

The aortic dissection diagnosis must be evoked biasfacing any brutal pain in the thorax (the chest).

The physician then searches for a cardiac murmur of aortic insufficiency on auscultation: he questions about a dissection and the attack of the ascending aorta (beginning of the thoracic aorta) at least in its initial part. Hypertension is frequently associated and must be quickly treated.

The physician must also search for an attack of the arteries situated downstream the aorta, because a tip of the aorta can detachand obstruct a smaller calibre artery situated down-stream.

The clinical exam achieved by the physician shows: the reduction or the abolition of a peripheral pulse (especially perceivable at the level of the arm), or an asymmetry of the B.P. in the upper members (for example 14/9 on an arm and 10/6 on the other arm).

2 - The pulmonary x-ray:

It only finds very indirect signs, which do not permit the diagnosis.

3 - Ultrasound of the heart and the aorta:

It is a simple, easily available and painless exam.

The ultrasound permits to visualise the diameter increase of the aorta in its ascending and horizontal portion, to visualise a pictureofmobile floating membraneor asplitting into twoof the aorta wall,the presence of an aortic insufficiencyor of an effusionof the pericardium(presence of liquid around the heart).

The colour ultrasound and the Doppler survey of the flows sharpen the above observations and sometimes permit to underline the flow in the false channel.

But the information brought by this exam is insufficient in very numerous cases and must be confirmed by other exams:

The cardiac and aorta ultrasound by trans-oesophageal way (the ultrasound probe, miniaturized, is then introduced throughthe mouth) is for some physicians the reference exam in the aortic dissection permitting a visualisation of the whole thoracic aorta. However this exam is not always implemented in emergency because of its “aggressive” character responsible for an increase of the B.P., which can aggravate the aortic dissection.

Thus, as testified by the photograph below, the dissection of the aorta can clearly be visualised.

Section of the thoracic aorta obtained with the trans-oesophageal
ultrasound, showing an aortic dissection.

4 - Scan and Magnetic Resonance Imagery:

The scan of the thorax preciselylocalizes the lesion corresponding to the dissection and the secondary localizations. This exam is very often used in the framework of the emergency.

Thoracic scan underlining a dissection of the aorta.

The Magnetic Resonance Imagery (MRI) is distinctly superior in terms of picture quality, but the number of equipments is still limited and this exam is not achieved in emergency.

Whatever, these exams demand the patient's displacementtoward a radiology unit, which is not always possible.

5 - Finally, the arteriography of the aorta is more and more rarely achieved:

It makes the exact check-up of the dissection: site, anatomical type, orifices of entry, and extension to the collateral arteries. In practice, the opportunities to use it are rare, in particular in the framework of the emergency.

Arteriography of the aorta.
This exam underlines a dilation of the descending thoracic aorta.

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File last modified on june 15, 2006