What is an aortic dissection?
- when a separation has occurred in the aortic wall, causing blood flow into a new false channel
- sometimes discrete intimal tear
- acute AD if <14 days old
Risk Factors for aortic dissection
- atherosclerotic aneurysmal disease
- Marfan syndrome
- Ehlers-Danlos syndrome
- bicuspid aortic valve
- annulo-aortic ectasia
- coarctation
- smoking
- Fx of aortic aneurysm/dissection
- hypertension
Weak RFs
- age
- giant cell arteritis
- overlap connective-tissue disorders
- surgical/catheter manipulation
- cocaine/amphetamine use
- heavy lifting
- pregnancy
- non-diabetic
Classification of aortic dissections
Stanford:
- Type A: dissection involves the ascending aorta with or without involvement of the arch and descending aorta
- Type B: dissection doesn’t involve the ascending aorta. Mainly involves only the descending thoracic and/or abdominal aorta
Onset:
- hyperacute <24hrs
- acute <14 days
- subacute 15-90 days
- chronic >90 days
DeBakey:
- Type 1: Tear originates in the ascending aorta and involves it and arch, some of the descending
- Type 2: Dissection confined to the ascending aorta
- Type 3: Tear originates distal to the left subclavian artery and extends through the thoracic aorta or extends beyond the visceral segment
Case History of aortic dissection
1) A 59-year-old man presents to the accident and emergency department with a sudden onset of excruciating chest pain, which he describes as tearing. He has a history of hypertension. On physical examination, his heart rate is 95 beats per minute. Blood pressure is 195/90 mmHg in the right arm and 160/80 mmHg in the left arm. Pulses are absent in the right leg and diminished in the left.
Presentations
- acute chest/back/interscapular/abdo pain
- abrupt onset
- severe
- ripping or tearing
- symptoms of stroke or visceral or acute limb ischaemia may be present
- haemodynamically shock
- 10% without pain
- heart failure signs, cardiac tamponade, left pleural effusion
Perfusion deficit
- pulse deficit/difference
- systolic bp difference in arms
- paraesthesia
- Paraplegia
Auscultation- diastolic decrescendo murmur
Fetaures of Marfans syndrome: tall stature, arachnodactyly, pectus excavatum, hypermobile joints, high-arched palate, narrow face
Features of Ehlers-Danlos syndrome: Type IV, translucent skin, easy bruising, hypermobility of small joints, premature skin ageing (acrogeria)
Treatment of aortic dissection
- ECG- ST segment depression
- x-ray
- blood tests- d-dimer (ruling out AD)
- CT
- TTE - transthoracic echocardiography
- Magnetic resonance angiogram
- Intravascular USS- type B dissection
- high sensitivity troponin
- renal function tests- elevated urine, creatinine
- LFTs- AST, ALT
- lactate- bowel ischaemia/metabolic acidosis- elevated
- FBC- anaemia
- G & S- surgery prep
- blood gas- metabolic acidosis -procalcitonin- differeniate b/w SIRS and sepsis
Other differentials to aortic dissection
- ACS
- Pericarditis
- AA
- MSK pain
- PE
- Mediastinal tumour
Treatment algorithm for aortic dissection
INITIAL
- Suspected aortic dissection: haemodynamically unstable:
- advanced life support with haemodynamic support: SpO2 94-96% / 88-92% if hypercapnic ; IV fluid resus- Ringer’s lactate/Hartmann’s solution, inotropes
- opioid analgesia- morphine sulfate 2.5-10mg IV
ACUTE
1) Confirmed type A AD:
- BB- labetalol 50mg IV OR metoprolol 2.5-5mg IV
- OR non-dihydropyridine Ca-channel blocker- diltiazem OR verapamil (HR <60)
- analgesia - morphine sulphate 2.5-10mg
- vasodilator- sodium nitroprusside
- open surgery or endovascular repair
2) Confirmed Type B AD: complicated
- BB- labetalol 50mg IV OR metoprolol 2.5-5mg IV
- OR non-dihydropyridine Ca-channel blocker- diltiazem OR verapamil (HR <60)
- analgesia - morphine sulphate 2.5-10mg
- vasodilator- sodium nitroprusside
- endovascular repair or open surgery: TEVAR- thoracic endovascular aortic repair
3) Confirmed Type B AD: uncomplicated
SAME AS ABOVE
-endovascular repair- TEVAR
ONGOING
- Chronic aortic dissection
- > 90 days since symptom onset
- BB= bisoprolol 5-10mg
- additional antihypertensive, at least 2: angiotensin-II receptor antagonist (losartan 50mg for 18-75yrs), ACE inhibitor (enalapril 5mg), Ca-channel blocker (nifedipine 10mg), thiazide-like diuretic (indapamide 2.5mg)
- lifestyle advice- stop strenuous exercise
- RF management- LDL<70, smoking
- EV repair or open surgery
Complications of AD
- cardiac tamponade
- aortic incompetence
- MI
- aneurysmal degeneration/rupture
- regional ischaemia
- left arm ischaemia/subclavian steal syndrome
- endoleak
Prognosis of AD
- syncope at presentation associated with worse outcomes
- deadly triad = hypotension/shock (not syncope), lack oof chest/back pain, branch vessel involvement
