- Clinical science
An aortic dissection is a tear in the inner layer of the aorta which leads to a progressively growing hematoma between in the intima-media space. It commonly occurs in hypertensive males between the 4th and 6th decade. Patients complain of a sudden onset and severe pain radiating into the thorax, back, or abdomen. Initial chest x-ray shows a widened mediastinum. The diagnosis is confirmed with a contrast-enhanced CT in stable patients and transesophageal echocardiography in unstable patients. Treatment options range from conservative measures (e.g., blood pressure optimization) to surgery (aortic prosthesis), depending on the localization and severity of the dissection. Complete occlusion of branching vessels and aortic rupture are common complications. Even with treatment, mortality rates associated with aortic dissection are high.
- Incidence: : 40–80 years (Peak incidence: 60-80 years; in at the age of 30–50)
- Sex: ♂ > ♀ (3:1)
Epidemiological data refers to the US, unless otherwise specified.
Hypertension (most common)
- Approx. 70% of patients with aortic dissection have elevated blood pressure. This elevated pressure leads to propagation of the dissection and increases the risk of rupture.
- Exception: in patients < 40 years, less than 40% due to hypertension
- Trauma; (e.g., deceleration injury in a motor vehicle accident, iatrogenic injury end during valve replacements or graft surgery)
- Vasculitis with aortic involvement (e.g., syphilis, Takayasu's arteritis)
- Use of amphetamines and cocaine
- Third-trimester pregnancy (or early postpartum period)
- Open heart surgery
- Mucoid, microcystic degeneration of the media (Cystic medial necrosis )
- Hypertension (most common)
- Type A; (proximal; ; DeBakey type I and II): ascending aorta dissection, including retrograde extension from the descending aorta (independent of the site of origin and propagation)
- Type B; (distal; ; DeBakey type III): descending aorta dissection, originating distal to the left subclavian artery
DeBakey classification (rarely used)
- Anatomic site of origin
Transverse tear in the aortic intima (“entry”) → blood enters the media of the aorta and forms a false lumen in the intima-media space → hematoma forms and propagates longitudinally downwards
- → rising pressure within the aortic wall → rupture
- → occlusion of every single branching vessel (e.g., coronary arteries, arteries supplying the brain, renal arteries, arteries supplying the lower limbs) → ischemia in the affected areas (see “Complications” below)
- → a second intimal tear may result in a “reentry” into the primary aortic lumen.
- Sudden and severe tearing/ripping pain
- ↑ BP (if the patient is hypotensive, consider shock from blood loss or a cardiac tamponade)
- Asymmetrical blood pressure and pulse readings between limbs
- Syncope, diaphoresis, confusion or agitation
- A heart murmur (an aortic regurgitation in a proximal dissection)
- Initial imaging: Chest x-ray (AP view) showing a widened mediastinum (> 8 mm)
- Definitive diagnostic tests (determine the type of lumen, location, and extent of the dissecting membrane)
- ECG: in all patients, although normal or signs of left ventricular hypertrophy
- See also
The differential diagnoses listed here are not exhaustive.
Stanford A dissections; (involvement of the ascending aorta) require immediate surgery; , while Stanford B dissections are generally treated conservatively unless complications (e.g., rupture or occlusion) occur.
- Sedation and analgesia (e.g., morphine)
- Adequate resuscitation
- Control hypertension
- Open surgery with a polyester graft implantation
- Possibly, endovascular treatment: aortic stent implantation (only in type B dissections and if the operative risk is too high)
Avoid thrombolytic therapy in patients with suspected aortic dissection!
- Aortic rupture and acute blood loss: acute back and flank pain (tearing pain); , symptoms of shock → indication for emergency surgery
- Complications of Stanford type A dissections
- Complications of both Stanford type A and B dissections
- Bleeding into the thorax, mediastinum, and abdomen
- Arterial occlusion followed by ischemia of the:
We list the most important complications. The selection is not exhaustive.
- Generally, the 30-day mortality is high
Type A dissection
- After surgery ∼ 30%
- Conservative treatment: ∼ 60%
Type B dissection
- Conservative treatment ∼ 10%
- After surgery ∼ 30%
- Blood pressure control
- Smoking cessation
- Screening and repair of rapidly expanding aneurysms (also see “Therapy” and “Prevention” sections in s)