Approach

Appropriate treatment is determined by accurate diagnosis of aortic dissection according to the following criteria:

  • Type A (ascending)

  • Uncomplicated type B (descending)

  • Type B (descending) with end-organ ischemia.

[Figure caption and citation for the preceding image starts]: Proximal dissectionFrom the collection of Dr Eric E. Roselli; used with permission [Citation ends].com.bmj.content.model.Caption@7a44d1bd[Figure caption and citation for the preceding image starts]: 3D CT, distal dissectionFrom the collection of Dr Eric E. Roselli; used with permission [Citation ends].com.bmj.content.model.Caption@564ea0d6

Initial management

Local resuscitation protocols should be followed. Supplemental oxygen and hemodynamic support with intravenous fluid resuscitation and judicious use of inotropes is recommended in cases of incipient renal failure and hypovolemic shock. See Acute kidney injury and Shock.

Initial management of both type A and B dissections involves medical therapy, regardless of definitive treatment.[10][14]​

Intravenous beta-blockers are used to achieve systolic blood pressure less than 120 mmHg, or to lowest blood pressure that maintains adequate end-organ perfusion and an appropriate target heart rate.[4]

Recommendations for target heart rate vary and local protocols should be followed; the American College of Cardiology/American Heart Association (ACC/AHA) recommend a target heart rate of 60 to 80 bpm; the Society of Thoracic Surgeons/American Association for Thoracic Surgery (STS/AATS) recommend maintaining a heart rate of <70 bpm; the European Society of Cardiology (ESC) recommends a heart rate of <60 bpm as the target for medical therapy.[6][14][4]​​ 

In patients with contraindications (e.g., acute aortic regurgitation, heart block, bradycardia) or intolerance to beta-blockers, initial management with an intravenous nondihydropyridine calcium-channel blocker is reasonable for heart rate control.[4]

Invasive monitoring of BP with an arterial line in an ICU setting is recommended to decrease aortic wall stress.[4]

If a beta-blocker (or nondihydropyridine calcium-channel blocker) alone fails, vasodilator therapy (e.g., nitroprusside) should be added.[14][4]​​

To decrease sympathetic tone and facilitate hemodynamic stability, pain should also be controlled with intravenous opioids.[10][14]​ It should be noted that morphine causes vasodilation and reduces the heart rate by increasing vagal tone. Intravenous nonsteroidal anti-inflammatory drugs (e.g., ketorolac) may not be suitable because of the risk of inducing hypertension and adverse renal effects.[4]

Type A dissection

In patients presenting with suspected or confirmed acute type A aortic dissection, emergency surgical consultation and evaluation with immediate surgical intervention is recommended, due to the high risk of associated life-threatening complications.[4]​ The mortality rate of medical management alone for acute type A aortic dissection is two to three times that of surgical intervention.[4] 

In patients who are stable enough, transfer from a low- to high-volume aortic center is reasonable in order to improve survival.[4]

Depending on the extent of retrograde extension, the aortic valve may or may not need to be repaired or replaced.[10] This is to prevent cardiac tamponade or fatal exsanguination from aortic rupture. Therapeutic options include: open aortic arch replacement; transposition of supra-aortic branches with subsequent endovascular repair; total endovascular repair; or the frozen elephant trunk repair technique, which combines open repair of the proximal aorta under deep hypothermic circulatory arrest, together with placement of thoracic stent grafts into the distal aortic arch and upper descending thoracic aorta.[34]

In patients with renal, mesenteric, or lower extremity malperfusion, immediate operative repair of the ascending aorta is recommended.[4]

In patients presenting with clinically significant mesenteric (e.g., celiac, superior mesenteric) malperfusion, immediate mesenteric revascularization via endovascular or open surgical intervention before ascending aortic repair is also reasonable.[4]​ Evidence of mesenteric malperfusion includes abdominal pain, bowel ischemia, lactic acidosis, elevation of liver function test results.[4]

Of note, stent grafts designed for total endovascular aortic arch repair are currently only available as part of a clinical trial, and thus the use of this approach using off-the-shelf stent grafts is off-label.

One meta-analysis of comparator observational studies reported lower stroke and mortality rates, but higher spinal cord ischemia events, with the frozen elephant trunk technique compared with conventional aortic arch surgery.[43] Longer term follow-up is necessary, and ideally evidence from randomized controlled trials; however, the technologies designed to treat aortic arch pathology continue to evolve.[44]

Complicated acute type B dissection

Urgent surgical or endovascular intervention is required if type B dissection is complicated by rupture, visceral or extremity ischemia, aneurysmal expansion, or persistent pain.[4]

Although both open and endovascular therapies are acceptable options, the endovascular approach - including fenestration and stenting - is gaining preference over the open technique for patients presenting with complications.[10][45][46][47][48]

ACC/AHA guidelines recommend endovascular stent grafting, rather than open surgical repair, in patients with acute type B aortic dissection with rupture in the presence of suitable anatomy.[4]​ The ACC/AHA note that an endovascular approach, rather than open surgical repair, is also reasonable in patients with other complications (e.g., branch artery occlusion and malperfusion, extension of dissection, aortic enlargement, intractable pain, or uncontrolled hypertension).[4]

The STS/AATS state that TEVAR is indicated for complicated hyperacute, acute, or subacute type B dissection in patients with favorable anatomy for TEVAR.[6] However, open surgical repair is reasonable over TEVAR as a more durable treatment in patients with connective tissue disorders who have type B dissection with progression of disease despite optimal medical therapy.[6]

Several studies have demonstrated high technical success rates for endovascular stenting to seal proximal entry tears. This promotes false lumen thrombosis and aortic remodeling. Static or dynamic side-branch obstruction can be relieved with additional endovascular stents. Compromised branches can be treated with ostial bare stents or stent grafts that enlarge the compressed true lumen. Survival rates and neurologic complications with endovascular treatment of type B dissections are favorable compared with those of open surgery.[6][47][48][49]

In the US, there is currently one endovascular stent specifically approved for placement in patients with type B aortic dissection. This is a modular system consisting of two components: a covered stent graft intended to seal the entry tear and to exclude aneurysms associated with chronic dissection, and an uncovered stent that is intended to provide support to distal delaminated segments of nonaneurysmal aorta with dissection.[50] The uncovered portion of the stent can be placed in the visceral segment of the aorta, which allows for the placement of stent grafts within individual visceral vessels as necessary. One prospective multicenter study using this device reported favorable clinical and anatomic outcomes for the treatment of rupture and malperfusion secondary to acute, complicated type B aortic dissection.[51] Long-term outcomes of this device remain to be determined.

[Figure caption and citation for the preceding image starts]: Proximal dissectionFrom the collection of Dr Eric E. Roselli; used with permission [Citation ends].com.bmj.content.model.Caption@7f137aa2[Figure caption and citation for the preceding image starts]: 3D CT, distal dissectionFrom the collection of Dr Eric E. Roselli; used with permission [Citation ends].com.bmj.content.model.Caption@1ab095bf

Uncomplicated acute type B dissection

Patients with uncomplicated type B aortic dissection (i.e., without end-organ malperfusion) are usually managed medically with blood pressure and pain control during the acute phase (less than 14 days).[24][10][14][34] The ACC/AHA and STS/AATS state that optimal medical therapy remains the recommended treatment for patients with uncomplicated type B dissection.[6][4]​​

Thoracic endovascular aortic repair

Thoracic endovascular aortic repair (TEVAR) is increasingly performed in patients with uncomplicated dissections in the subacute phase (14 days to 6 weeks) to promote false lumen thrombosis and prevent aneurysmal degeneration. However, there is considerable heterogeneity of published data; results from meta-analyses evaluating TEVAR in patients with type B aortic dissection should be interpreted with caution.

One meta-analysis found no evidence for survival benefit at 1 year for patients with acute uncomplicated type B aortic dissection (TBAD) treated with TEVAR compared with those receiving best medical therapy.[52] Another meta-analysis found that TEVAR did not prevent aneurysmal degeneration in patients treated for acute or chronic (including complicated) TBAD, noting that long-term data are lacking.[53] Results from one meta-analysis of a mixed patient population (complicated/uncomplicated, acute/subacute TBAD) and one randomized study of patients with stable TBAD, respectively, suggest that aneurysm-specific outcomes may be favorable over the longer term following TEVAR.[54][55]​ Larger trials with longer-term data are still required.[4]

There may be some benefit to early endovascular intervention in patients with uncomplicated acute type B aortic dissection with refractory pain and hypertension.[56] TEVAR in the subacute phase of type B dissection may be associated with a lower risk of complications, particularly retrograde type A dissection.[57]

Chronic aortic dissection

Aortic dissection is a lifelong condition and is defined as chronic at >90 days after the first onset of symptoms.[24][10][14] This includes patients with persisting type A dissection of the descending aorta following surgical repair of the aortic archery.[10] The patient may also be diagnosed with chronic aortic dissection if the first diagnosis of aortic dissection is picked up as an incidental finding at the chronic stage (e.g., an incidental finding of mediastinal widening or prominent aortic knob on chest x-ray).[10] The largest group of patients with chronic aortic dissection (approximately 60%) are patients with surgically corrected ascending (Stanford type A) dissection with a persistent false lumen distal to the surgical repair.[24] Patients with nonoperated type A dissection rarely live past the acute event; hence, chronic dissections of the ascending aorta are exceedingly rare.[24]

Patients with chronic aortic dissection are managed with the same medical principles as those used in the acute phase. Blood pressure control is continued after discharge from the hospital.[58] Beta-blockers and ACE inhibitors are usually required, with additional antihypertensives such as diuretics or calcium-channel blockers, if necessary, to achieve a systolic blood pressure less than 120 mmHg and an appropriate target heart rate. In practice a specialist will aim for a target heart rate for chronic aortic dissection that is the same as for acute aortic dissection. Recommendations for target heart rate vary in acute aortic dissection and local protocols should be followed; the STS/AATS recommend maintaining heart rate <70 bpm and the ESC recommends heart rate <60 bpm as the target for medical therapy.[6][14] At least 40% of patients will require combination treatment to control blood pressure.

Patients should be advised to avoid contact sports and strenuous physical activities (such as isometric heavy weight lifting, pushing, or straining that would require a Valsalva manoeuvre) to reduce aortic wall shear stress due to sudden rises in arterial blood pressure during exercise.[10][14] However, activities with low static and dynamic stress (mild aerobic exercise and daily activities) can be continued.[10][14] The patient should also avoid cocaine or other stimulating drugs such as methamphetamine.[14]

Other interventions include management of risk factors for atherosclerotic disease; in particular: smoking cessation and lipid-lowering therapy (target of LDL-cholesterol <70 mg/dL).[14] 

Patients with chronic aortic dissection may need open surgical repair or endovascular therapy (TEVAR) in their lifetime. Indications for surgery in uncomplicated chronic aortic dissections depend on aortic diameter, pathogenesis, and the presence of symptoms. Asymptomatic chronic thoracic and thoracoabdominal aortic dissections with a maximal orthogonal aortic diameter of 6.0 cm in patients without connective tissue disease warrant repair.​[24][10][59] Rapid growth rate >0.5 cm per year also may be an indication for repair.[24] Patients with connective tissue diseases and those with a family history warrant more careful consideration and may warrant earlier intervention (diameter of 5.0–5.5 cm).[24][60][61]

TEVAR has been increasingly used for thoracic and thoracoabdominal aortic aneurysm repair occuring after aortic dissection because of the low acute risk compared with open repair and the potential to reduce aortic mortality and reoperations compared with medical therapy.[24] However, TEVAR faces anatomic and morphological limitations to successfully treating this disease, particularly in the chronic stage.[24][62][63][64][65] TEVAR may be a viable rescue option for patients with type A dissection who are not eligible for open surgical repair.[66]

The goals of TEVAR therapy are to:

  • cover the entry tear

  • treat or prevent impending rupture

  • re-establish organ perfusion

  • restore flow in the true lumen

  • induce the false lumen thrombosis.

One Cochrane review noted a lack of randomized controlled trials (RCTs) and controlled clinical trials investigating the effectiveness and safety of TEVAR compared to open surgical repair for patients with complicated chronic type B aortic dissection. The investigators were therefore unable to provide any evidence to inform decision-making on the optimal intervention for these patients.[67]

In a retrospective analysis of 80 patients who underwent TEVAR for chronic type B aortic dissections, complete false lumen thrombosis was achieved in 52% and aneurysm diameter was stabilized or reduced in 65%. Five-year overall survival was 70%.[62] In a prospective multicenter trial from China, TEVAR for chronic type B aortic dissection decreased the risk of aortic-related mortality compared with optimal medical therapy alone at 4 years, but failed to improve overall survival. The thoracic aorta diameter decreased significantly in the TEVAR group, but increased in the medical therapy group.[68] There currently are no longer-term data on the efficacy of TEVAR for chronic type B aortic dissection.

Use of this content is subject to our disclaimer