Thoracic aortic dissection

Histopathological picture of thoracic aortic dissection in a patient without Marfan's syndrome. The damaged part of the aorta was surgically removed and replaced with a vascular prosthesis. Victoria blue and HE staining.

Thoracic aortic dissection is a sudden vascular event with a dramatic course, immediately life-threatening.

Pathogenesis

• The cleavage of the aortic wall caused by the penetration of blood through the crack in the intimate and media.
• The rupture occurs most often above the coronary arteries or in the aortic isthmus.
• From the site of the crack, the dissection can spread peripherally and centrally, it can affect the whole circumference or only a part. The canal can also spread to the carotid or visceral branches of the aorta.
• At the end of the dissection, another reentry may occur and a communicating channel is created.

Consequences

• The canal oppresses the right aortic lumen even at intervals.
• The dissection created above the coronary arteries often spreads centrally and tears the commissures of the aortic valve, resulting in severe insufficiency.

Causes

• Degenerative media changes ( cystic medionecrosis ) or aneurysm in combination with hypertension , less often atherosclerosis .
• We often encounter it in Marfan's syndrome (young patients) and in other systemic connective tissue diseases ( Ehlers-Danlos syndrome , Loyes-Dietz syndrome ).
• Other predisposing factors include bicuspid aortic valve , aortic coarctation or trauma (falls, car accidents).

CLICK ON LINK FOR VIDEO ON AORTIC DISSECTION:

https://www.wikiskripta.eu/w/Soubor:Aortic_dissection.webm#file

Classification

DeBakey and Stanford classification

DeBakey classification

• Type I - begins in the ascending aorta and continues to the abdominal,
• Type II - bounded on the area of ​​the ascending aorta,
• Type III - begins in the aortic isthmus and affects the descending aorta, or. continues to the abdomen.

Stanford classification

• Type A - the ascending aorta is affected (2x more common than type B),
• Type B - affected is the descending aorta.

• 

  CT dissection of the aneurysmal ascending aorta

• 

  CT dissection of the descending aorta

Clinical picture

Autopsy finding - aortic dissection

• Sudden shocking pain behind the sternum and back can progress to the abdomen.
• Sometimes a shock condition follows ( bleeding , tamponade , acute heart failure) - they usually die of sudden death.
• Sometimes the symptoms gradually subside and the condition stabilizes temporarily or permanently.
• Vascular symptoms:
  • different, depending on which aortic branches are oppressed or torn off,
  • cranial arteries - unconsciousness, hemiparesis,
  • subclavia - ischemia HK,
  • upper mesenterics - intestinal ischemia,
  • renal arteries - anuria , oliguria ,
  • peripheral arteries - deficit or asymmetry of pulsations (typically variable over time), lateral asymmetry of pressures on HKK, etc.

Diagnosis

ECHO (longitudinal section) finding of aortic dissection

CT 3D dissection angiography - right and false lumen

• Typical history (sudden acute pain),
• physical examination: deficiency or asymmetry of pulsations in peripheral arteries,
• auxiliary methods:
  • exclusion of AIM ( ECG ),
  • Chest X-ray - extension of the shadow of the upper mediastinum to the left,
  • ECHO , CTA , aortography.
• The sovereign method - transesophageal echocardiography - determines the diagnosis in 98%.

Indications for operation

• By type, extent, vascular disability and general condition:
  • for type A, about half of the victims die within 24 hours, the hope decreases with each passing hour → type A is always indicated for immediate surgical treatment,
  • for type B, we choose a predominantly conservative procedure if there is no vascular symptomatology or there is no risk of rupture.

Therapy

• Immediately after the diagnosis, we start drug treatment: antihypertensives , beta blockers and vasodilators , diuresis support . We monitor the patient, administer analgesics (insufficient pain treatment leads to antihypertensive failure). Cardiac tamponade should be ruled out by echocardiography in patients with hypotension.

Type A

Principle of operation - we try to cancel the inflow into the aneurysm, several methods:

• transverse intersection of the ascending aorta at the site of the rupture, suturing of both ends of the aorta over the outer and inner meshes, subsequent suture of the aorta,
• resection of the ascending aorta, strengthening of the ends with a suture and replacement of the aorta with a prosthesis,
• Bental's operation - replacement of the aortic valve and ascending aorta by a conduit with a valve, implantation of coronary arteries into the prosthesis,
• closing the entrance to the dissection with tissue glue with aortic suture or with a prosthesis,
• implantation of an intraluminal ring prosthesis into the ascending aorta.

Type B

• We treat uncomplicated type B dissection conservatively (stabilization, antihypertensives).
• For complicated dissections, it is necessary to proceed to invasive treatment:
  • endovascular stent graft implantation,
  • surgical solution.

Principle of surgical treatment

• In the right flank, from a left thoracotomy, usually without ECC, a bypass is sometimes used to protect the kidneys and spinal cord from ischemia .

• Resection of a section with a crack, replacement with a prosthesis, or implantation of an intraluminal prosthesis - this will cancel the entry and it will close with thrombosis. The operation is more complicated when the visceral arteries leave the dissection canal - a laparotomy must be performed and those arteries reconnected to the aorta.

Complication

Stanford A dissection can cause acute aortic insufficiency, heart failure, hypotension. Closure of the coronary arteries by dissection leads to AIM (most often a diaphragmatic infarction occurs by occlusion of the ACD ). Rupture of the pericardial dissection creates a cardiac tamponade.

Stanford B dissection can be complicated by spinal, visceral, renal or limb ischemia.

Links

related articles

• Thoracic aortic surgery
• Aneurysm
• Aortic dissection / case report

External links

• Aortic dissection - video on youtube.com NEFČNÍ

References

• ZEMAN, Miroslav, et al. Special surgery. 2nd edition. Prague: Galén, 2006. 575 pp.  ISBN 80-7262-260-9 .

• ČEŠKA, Richard, ŠTULC, Tomáš, Vladimír TESAŘ and Milan LUKÁŠ, et al. Internal. 3rd edition. Prague: Stanislav Juhaňák - Triton, 2020. 964 pp.  ISBN 978-80-7553-780-5 .

Source

• BENEŠ, Jiří. Study materials  [online]. [feeling. 5/17/2010]. < http://jirben.wz.cz >.