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AORTIC DISSECTION

 WHAT IS AORTA  ?

A combination of lifelong exposure to this kinetic energy and possible disruption of elastin architecture make it liable for meechanical dilatation which is called aneurysm.

Aorta is the large and major artery arising from the left heart otherwise called left ventricle,first courses up giving blood vessels to brain and both upper arms, arches down in the chest,travells down,pierces down the diapragm,become abdominal aorta, gives branches to all abdominal visera and end up dividing into two branches to lower limb vessels.

All blood vessels have a three layer wall, tunica adventitia, tunica media and tunica intima respectively from outside in. Arteries, arterioles , capillaries and veins have variations in their walls respective to their function. They are classified  as impedence vessels, resistance  vessels, exchange vessels and capacitance vessels.

DISSECTION .jpeg

DISSECTION

 Aorta is the impedence vessel as it has to withstand the tremendous kinetic energy  which it is imparted while getting ejected forcefully from the left side of heart.

ully from the left ventricle. So unlike the other small vessels ,it is provided with much amount of elastin fibres in its tunica media.  

A vessel is said to be aneurysmal if it gets dilated one and half times its original diameter

WHAT ARE THE  COMMON DISEASES OF AORTA ?

     AORTIC ANEURYSM

     AORTIC DISSECTION

     AORTIC OCCLUSIVE DISEASE

WHAT IS AORTIC DISSECTION  ?

    Dissection means separation. Aortic dissection means ,a separation within the walls of aorta. Aortic wall consists of three layers, namely adventitia,media and intima. It may be due to the rupture of a blood vessel traversing through its media, or blood entering the wall through a breach in the integrity of its innermost wall.

The blood traverse down mostly, rarely up , continously rearing apart the wall. Some time it may end up creating two lumens, the new lumen being called false lumen. Major blood vesses like the ones going to brain, limbs or to the kidneys may end up arising from the false lumen thereby ending up with compromised blood supply.

DISSECTION PATHOLOGY

DISSECTION PATHOLOGY

WHAT ARE THE TYPES OF AORTIC DISSECTION ?

There are many classifications. They are based on the site of origin and extent of dissection.

     TYPE I: Starts in the ascending aorta and stops just before the innominate.

     TYPE II: Starts in the ascending aorta extens farthur down beyond innominate and sometimes into thoracic and abdominal aorta.

     TYPE III: Starts in descending thoracic aorta and travells down.

WHAT ARE THE SYMPTOMS OF AORTIC DISSECTION  ?

  Acute aortic dissections can have a dramatic onset of hemodynamic collapse sometimes with catatrophic outcome. More rarely symptoms may be more insidious , mimicking an acute heart attack ,vague abdominal pain, renal failure, stroke or limb ischemia. Some dissections especially that of type iii type can have chronic course without patient having any symptoms at all.

Some dissections involving ascending aorta may involve aortic valve and coronaries reslting in coronary ischemia and heart attack or sudden heart failure from valve regurgitation.

WHAT IS AORTA ?

Aorta is the large and major artery arising from the left heart otherwise called left ventricle,first courses up giving blood vessels to brain and both upper arms, arches down in the chest,travells down,pierces down the diapragm,become abdominal aorta, gives branches to all abdominal visera and end up dividing into two branches to lower limb vessels.

CAUSE OF DISSECTION

CAUSE OF DISSECTION

All blood vessels have a three layer wall, tunica adventitia, tunica media and tunica intima respectively from outside in. Arteries, arterioles , capillaries and veins have variations in their walls respective to their function. They are classified  as impedence vessels, resistance  vessels, exchange vessels and capacitance vessels.

DISSECTION ON CT

DISSECTION ON CT

WHAT CAUSES AORTIC DISSECTION  ?

Rupture of a vessels traversing the the media and the subsequent expanding hemetoma and ultimate release of this hemetoma into the ture lumen is the commonest cause of dissection. Diseases like Marfan syndrome or Ehrlish  Danlos syndrome where there is inherent weakness in the making of collagen fibres which make up the most of media has predliction.

WHAT ARE THE COMPLICATIONS OF AORTIC DISSECTION ?

Sudden death from hemodynamic collapse, acute heart failure from cardiac ischemia or valvular regurgitation, stroke, limb ischemia, renal failure, intestinal ischemia, percardial tamponade or blood collection around the heart ,hemothorax or collection of blood in the chest cavity, hemoperitoneum or collection of blood in the abdominal cavity are some of the complications of aortic dissection.

DISSECTION FLAP

DISSECTION FLAP

DISSECTION FLAP IN SONOGRAM

DISSECTION FLAP IN SONOGRAM

SHOULD WE TREAT AORTIC DISSECTION AT ALL  ?

Aortic dissections can be life threatening and has to be treted if possible except some chronic type iii disections which are best treated conservatively. Once the condition is suspected ,the action has to be urgent because the damage increases as the time passes.

Stroke or renal failure may be some of nonrecoverable sequele of delayed treatment of dissection.  Stroke is characterised by alteration in the conscious state or weakness in the movement of hands or legs or weakness of facial muscles.

WHAT ARE THE TREATMENTS OF AORTIC  DISSECTION  ?

Most of the time dissections are life threatening and has to be dealt urgently.

Urgent operations or stentings may be lifesaving. Chronic type iii dissections may be treated conservatively.