Management of acute type A aortic dissection

INTRODUCTION — Aortic dissection is defined as a tear in the innermost layer of the aortic wall (ie, intima), which results in high-pressure blood flow between the layers of the aorta, creating a true and false lumen. Type A aortic dissection involves the ascending aorta, regardless of the site of the primary intimal tear. Acute type A aortic dissection is a surgical emergency. Affected patients are at high risk for life-threatening complications (eg, cardiac tamponade from hemopericardium, aortic regurgitation, stroke, aortic rupture, myocardial infarction). Without surgical intervention, mortality rates are as high as 1 to 2 percent per hour after symptom onset [1].

The initial management of acute type A aortic dissection and considerations for proceeding with surgery, as well as related morbidity and mortality are reviewed. The recommendations provided are generally in agreement with multidisciplinary cardiovascular guidelines [2,3].

Surgical techniques to manage type A aortic dissection are reviewed separately. (See "Surgical and endovascular management of acute type B aortic dissection".)

The management of acute and chronic type B aortic dissection are reviewed separately. (See "Overview of acute aortic dissection and other acute aortic syndromes" and "Management of acute type B aortic dissection" and "Management of chronic type B aortic dissection".)

EXTENT AND ETIOLOGY OF DISSECTION — The location of the aortic dissection and its etiology are important, as these impact management. The presence of acute type A aortic dissection and the extent of the dissection (figure 1) are confirmed using cardiovascular imaging. Diagnostic evaluation should be accomplished as promptly as possible. For patients who are hemodynamically unstable, transesophageal echocardiography can be used with high sensitivity [4]. For stable patients, computed tomographic angiography is more frequently chosen for reasons discussed elsewhere. (See "Clinical features and diagnosis of acute aortic dissection", section on 'Cardiovascular imaging'.)

High-risk medical conditions — High-risk medical conditions associated with aortic dissection are listed below and discussed in more detail separately (see "Clinical features and diagnosis of acute aortic dissection", section on 'Incidence and associated conditions'):

●Hypertension (abrupt, transient severe increase)

●Genetically mediated aortic disease

•Syndromic – Marfan syndrome (table 1), Loeys-Dietz syndrome, Vascular Ehlers-Danlos syndrome, Turner syndrome, familial aneurysm-osteoarthritis syndrome (SMAD 3 mutations)

•Nonsyndromic – Familial aortic aneurysm/dissection, bicuspid aortic valve, aortic coarctation

●Degenerative aortic disease including preexisting thoracic aortic aneurysm and abdominal aortic aneurysm

●Inflammatory conditions (eg, Takayasu arteritis, giant cell arteritis)

●Aortic instrumentation, trauma, or surgery

ACUTE MANAGEMENT — Clinical features of type A aortic dissection include a "classic" history of severe, stabbing chest and/or back pain, echocardiographic evidence of intimal flap in the ascending aorta, new murmur, signs of malperfusion (eg, stroke), or hemodynamic instability. Clinical features of acute aortic dissection and the distinction between type A and type B aortic dissection are reviewed separately. (See "Clinical features and diagnosis of acute aortic dissection".)

Surgical referral or transfer — As soon as acute type A aortic dissection is diagnosed, immediate cardiac surgical consultation is required, and if experienced cardiac surgical services are not available, the patient should be promptly transferred for definitive care. [5]

An experienced cardiovascular surgeon should be involved early in the course to discuss any decision for surgery and its timing, which must be individualized, accounting for the patient's clinical condition, age, comorbidities (eg, prior stroke, renal failure, hypertension, coronary heart disease), and patient and family wishes. (See 'Risk assessment' below and 'Decision for comfort care' below.)

Treatment at an aortic center is important for achieving optimal outcomes. In a review of nearly 17,000 United States Medicare beneficiaries diagnosed with type A aortic dissection (1999 to 2014), interfacility transfer to a high-volume hospital was associated with a 7.2 percent (95% CI 4.1-10.3) absolute risk reduction in operative mortality and with reduced long-term mortality (hazard ratio 0.81, 95% CI 0.75-0.87) [6]. The median distance needed for transfer to a high-volume hospital was 50.1 miles.

Resuscitation and anti-impulse therapy — For patients diagnosed with acute type A aortic dissection, management priorities include resuscitation for hypotensive patients, "anti-impulse therapy" to control heart rate and blood pressure, pain control, and identification of malperfusion syndromes, which may impact the nature of the repair (table 2) [5,7].

Patients often present with severe hypertension and are initially stabilized with fast-acting, intravenous beta-blockers (eg, esmolol or labetalol) or calcium channel blockers. Anti-impulse therapy lowers blood pressure and decreases aortic wall stress, reducing the risk of rupture during interim preparation for surgery. Medications and dosing used in acute type A aortic dissection are similar to other acute aortic syndromes and are reviewed separately (table 3). Administration of anti-impulse therapy should not interfere with the timely transfer of the patient or be administered when hypotension and/or concern for tamponade is present. (See "Overview of acute aortic dissection and other acute aortic syndromes", section on 'Acute medical management'.)

RISK ASSESSMENT — A complete preoperative history and physical exam is performed by the cardiac surgeon, identifying risk factors for specific etiologies of aortic dissection, comorbidity profile to assess suitability for operative repair, and for symptoms and signs of malperfusion syndromes (eg, altered mental status, abdominal pain, pulseless extremity), which affect prognosis.

Factors associated with a poor prognosis — In a review of 464 patients from an International Registry of Acute Aortic Dissections (IRAD) study who presented with aortic dissection, 72 percent of those with a type A dissection were treated surgically [8]. Reasons for medical therapy only included advanced age, comorbidity, patient refusal, or death prior to planned surgery. Poor prognostic factors in this study and others have included [8-19]:

●Age over 70 years

●Abrupt onset of chest pain

●Hypotension, shock, or tamponade at presentation

●Renal failure at presentation and before surgery

●Pulse deficit

●Abnormal electrocardiogram, particularly ST-segment elevation

●Prior myocardial infarction

●Previous aortic valve replacement

●Renal and/or visceral ischemia

●Underlying pulmonary disease

●Syncope/signs of stroke

In the IRAD review, logistic regression identified the first six factors as predictors of death [10]. Using a predictive score that incorporated these parameters, patients could be identified with subsequent in-hospital mortality rates that ranged from 2 to over 80 percent.

In review of 487 patients, preexisting cardiac disease (relative risk [RR] 3.7, 95% CI 1.8-7.4) and cardiopulmonary resuscitation (RR 6.8, 95% CI 2.3-20.2) were independent predictors of in-hospital death on multivariate analysis [11]. Causes of in-hospital death were low cardiac output (6.6 percent), major brain damage (5.9 percent), hemorrhage (2.2 percent), sepsis (1.8 percent), visceral ischemia (1.6 percent), multiple organ failure (1.4 percent), rupture of the thoracic aorta (1.2 percent), and respiratory failure (1.2 percent); four deaths occurred intraoperatively.

Decision for comfort care — Any decision for acute intervention must be tempered with judgement and patient preferences, particularly in older patients or in those with significant comorbid conditions since intervention for acute aortic emergencies, even in patients with few comorbidities and in the best surgical hands, is associated with a mortality rate exceeding 10 percent. However, age alone is not reason to withhold surgical treatment in a previously active patient. (See 'Risk assessment' above.)

Surgical intervention may be withheld in any patient with documented type A aortic dissection and with significant comorbidities that impact survival to one year or less such as with very advanced age and frailty, advanced malignancy, dementia, or patient/family wishes. Hemorrhagic stroke associated with acute type A aortic dissection is a relative contraindication to urgent surgical intervention. With thoughtful advance discussion of the likely poor outcomes associated with repair in high-risk groups, aggressive intervention can be avoided to allow the patient to die with dignity and peace.

CANDIDATES FOR REPAIR — Most patients can be considered candidates for immediate surgical repair of acute type A aortic dissection. Even in patients with malperfusion syndromes, survival is better with surgical intervention, although prognosis is significantly worse when multiple vascular beds are malperfused and when severe comorbidities are present.

Benefits of surgery — The survival benefits of surgery were shown in an International Registry of Acute Aortic Dissections (IRAD) review of 547 patients with a type A dissection, 80 percent of whom were treated surgically [10]. The main cited reasons for medical therapy were comorbid conditions, advanced age (mean of 80 years), and patient refusal. The in-hospital mortality rates were 27 and 56 percent for surgical and medical therapy, respectively, which is a difference that was due in part to increased comorbidity in medically treated patients. Not surprisingly, the patients who died had a higher rate of in-hospital complications, including neurologic deficits, coronary or mesenteric ischemia, acute renal failure, and limb ischemia.

Even the presence of acute myocardial infarction, which may be due to the involvement of a coronary ostium (particularly the right coronary artery), should not entirely exclude the option of rapid surgical intervention. However, patients with a stroke in progress are at increased risk for hemorrhagic cerebral infarction due to intraoperative heparinization. Thus, hemorrhagic stroke is a relative contraindication to urgent surgical intervention, as are major comorbidities.

In one of the IRAD studies, patients with acute type A dissection who were older than 69 years of age were less likely to be treated surgically compared with younger patients (64 versus 86 percent) [9]. However, older age alone should not preclude surgery [9,20]. In the registry report, although in-hospital mortality was significantly higher in older patients compared with younger patients (38 versus 23 percent), it was lower in older patients treated surgically compared with medical management [9]. Thus, surgery should be considered in older patients, even in some octogenarians with otherwise few comorbidities and good prognosis [9]. Females were also less likely to be treated surgically (71 versus 87 percent) [21]. As with older patients, females have a higher in-hospital mortality with surgical treatment than males (32 versus 22 percent), but they have a lower mortality compared with medical therapy (32 versus 54 percent).

Imaging evaluation — Imaging is necessary to confirm the diagnosis of type A aortic dissection and to evaluate the extent of the dissection. Along with physical examination, imaging also helps determine suitability of potential cannulation sites for cardiopulmonary bypass. As an example, the common femoral artery, which can be used as a cannulation site, may have significant atherosclerotic plaque or may be involved with the dissection. (See "Surgical and endovascular management of acute type A aortic dissection", section on 'Cannulation options'.)

Cardiovascular imaging studies, ideally electrocardiographic gated computed tomographic angiography, should be obtained and thoroughly reviewed by the surgeon for several critical pieces of information that potentially affect type and conduct of repair including:

●Location and extent of the intimal flap/dissection.

●Location of intimal tears and re-entry tears.

●Dissection involving cerebral vessels, which can alter cannulation cerebral protection strategies.

●Integrity of femoral and axillary arteries (potential bypass cannulation sites).

●Evidence and extent of pre-existing thoracic or abdominal aortic aneurysm.

●"Radiographic" evidence of malperfusion (poor filling of aortic branches or end organs).

●Presence of pericardial or pleural effusion.

●Degree of aortic calcification, atheromatous disease, or intramural hematoma (presence of a significant amount in the ascending aorta may preclude safe cross-clamping).

●Anatomic anomalies (eg, aberrant right subclavian artery (figure 2), vertebral artery directly from descending thoracic aorta, dominant left vertebral artery).

Echocardiography (transthoracic, transesophageal) can be used to define the severity and mechanism of aortic regurgitation that can complicate acute type A aortic dissection [22]. Intraoperative transesophageal echocardiography (TEE) also identifies regional wall motion abnormalities that would need to be considered and addressed. Moreover, type A aortic dissection that is compressing the coronary artery ostia (most commonly the right coronary artery) may require bypass grafting as part of the initial treatment. TEE becomes most useful for cases in which the patient is in extremis or if aortic dissection is suspected to have occurred during cardiac catheterization or cardiac surgery. TEE may also be helpful for confirming a diagnosis in equivocal cases prior to taking the patient to the operating room. (See "Clinical features and diagnosis of acute aortic dissection", section on 'Cardiovascular imaging'.)

Pursuing preoperative coronary angiography for patients with acute type A aortic dissection is of limited value; the resulting delay of surgery for type A aortic dissection increases the risk of cardiac tamponade or aortic rupture. In addition, engaging the native coronary arteries may be technically difficult due to the dissection. An increased prevalence of coronary heart disease has been noted in older patients with acute aortic dissection, and some have suggested that coronary angiography identifies critical stenosis that can be addressed while the patient is under cardiopulmonary bypass. There has also been concern that the presence of undiagnosed critical coronary stenoses may make weaning from cardiopulmonary bypass more difficult and can increase the risk of perioperative myocardial infarction or death. However, in a retrospective review of 122 patients who underwent emergency aortic surgery, primarily for a type A aortic dissection, in-hospital mortality was similar for those who did or did not undergo coronary angiography (22 versus 16 percent, respectively) including among those who had a prior myocardial infarction, which was the only predictor of in-hospital mortality [17]. Coronary angiography had no impact on the incidence of coronary artery bypass grafting (17 versus 25 percent), three-fourths of which were performed because of coronary artery dissection, not atherosclerotic disease.

AORTIC REPAIR — Acute type A aortic dissection continues to be considered a surgical emergency in patients who are deemed suitable operative candidates. Without surgical intervention, patients with acute type A aortic dissection are at high risk for life-threatening complications such as aortic regurgitation, cardiac tamponade, stroke, frank rupture, myocardial infarction, and organ malperfusion, with mortality rates as high as 1 to 2 percent per hour after symptom onset [1]. In a review of 487 patients, in-hospital mortality (including operative deaths) was 22 percent [11]. Most operations for type A aortic dissection are performed immediately following recognition; other acute aortic syndromes, in particular type A intramural hematoma, are often treated "urgently," with repair within 24 to 48 hours of diagnosis. (See "Overview of acute aortic dissection and other acute aortic syndromes".)

Preparation — Suitable patients are prepared for definitive surgery with baseline electrocardiogram, a full laboratory panel, and type and cross for blood products (eg, 6 units packed red blood cells, 4 units fresh frozen plasma, 2 units of platelets). (See "Anesthesia for aortic surgery with hypothermia and elective circulatory arrest in adult patients", section on 'Preanesthetic assessment and planning'.)

Thyroid function should also be assessed prior to surgery. In one study, a high TSH associated with subclinical hypothyroidism was an independent predictor of mortality [23].

Informed consent is obtained by the cardiac surgeon, along with a thorough discussion of the possibility of aortic valve replacement and preferences for valve type.

Options for repair — Most patients with acute type A aortic dissection are managed using open surgical techniques with a limited role for endovascular repair depending upon the extent of the dissection.

The general technique for repair of type A aortic dissection is reviewed briefly below, and in more detail separately. (See "Surgical and endovascular management of acute type A aortic dissection".)

Open surgical treatment involves:

●Excision of the intimal tear

●Obliteration of entry into the false lumen proximally

●Reconstitution of the aorta with interposition of a synthetic vascular graft (figure 3)

●Repair or replacement of the aortic valve

Patients with an intrinsically normal valve who have aortic regurgitation due to a correctable aortic lesion (incomplete leaflet closure, leaflet prolapse, or dissection flap prolapse) can often undergo successful aortic valve repair. Abnormalities that cannot be repaired (eg, Marfan aortic root dilation, bicuspid valve, aortitis) may require valve replacement [24]. An aggressive surgical approach, including a full aortic root or hemiarch replacement when the aortic valve, sinuses, or arch are involved, may not be associated with an increased operative risk [25,26]. (See "Overview of open surgical repair of the thoracic aorta", section on 'Ascending aorta' and "Overview of open surgical repair of the thoracic aorta", section on 'Aortic arch'.)

The "frozen elephant trunk repair" uses an open approach to surgically repair the ascending aorta while using a stent-graft to manage the descending aorta. Several case series have compared this technique with conventional open repair [27-29]. In one series, the false lumen was completely obliterated in 14 of 15 patients within three months [30]. In another review, a triple-branched stent-graft was placed into the three arch vessels and descending aorta in 30 patients with acute type A dissection [31]. The procedure was technically successful in all patients, and aortic cross-clamp and lower body ischemic times were 84 and 31 minutes, respectively, which is generally much lower compared with conventional open surgical treatment. However, debate remains whether the risk of stroke or other complications is higher for total arch replacement and frozen elephant trunk repair compared with conventional ascending aortic or hemiarch repair. While data are limited, the stroke risk appears similar at 5 to 10 percent.

A possible alternative to surgery in patients with type A dissection is endovascular stent-grafting; experience is limited in patients with acute dissections. An early feasibility study (ARISE) using the Gore Ascending Stent Graft device is underway [32]. In this study, treatment is limited to patients at high- or prohibitive operative risk and whose anatomy is favorable (eg, minimal aneurysmal disease, intimal tear in the ascending aorta, proximal landing zone above the coronary arteries). Devices used in for endovascular repair and techniques are reviewed separately. (See "Endovascular devices for thoracic aortic repair", section on 'Advanced devices' and "Endovascular repair of the thoracic aorta".)

Although initial repair of the dissection may result in resolution of peripheral ischemia, stenting and/or balloon fenestration of the dissecting membrane may be needed for patients with visceral or peripheral ischemia after the initial repair [4,33]. (See "Surgical and endovascular management of acute type B aortic dissection", section on 'Fenestration of septum' and "Surgical and endovascular management of acute type B aortic dissection", section on 'Stenting visceral branch obstruction'.)

LONG-TERM MANAGEMENT — Patients who survive acute type A aortic dissection remain at risk for long-term complications [2,3]. The three main management principles involve ongoing anti-impulse therapy in the form of blood pressure lowering to minimize aortic wall shear stress; evaluation for high-risk clinical conditions; and serial imaging to detect signs of dissection progression, re-dissection, or aneurysm formation with reoperation, when indicated.

Ongoing medical therapy — Following aortic repair, once heart rate control has been achieved and the patient is tolerating an oral diet, intravenous beta-blocker therapy (or other antihypertensive therapy) can be switched to an oral route. All patients should be maintained on lifelong therapy to reduce systemic blood pressure and the rate of rise in systolic pressure, both of which will minimize aortic wall stress [4]. Although not evaluated in controlled trials, target blood pressure is less than 120/80 mmHg [4]. Combination antihypertensive drug therapy is usually required.

In addition, depending on the etiology of the dissection, other medical therapies may be indicated, such as ongoing lipid lowering therapy and smoking cessation (atherosclerotic disease). (See "Prevention of cardiovascular disease events in those with established disease (secondary prevention) or at very high risk".)

Avoidance of strenuous physical activity that would lead to a spike in blood pressure is also recommended, though unproven, as another method to reduce aortic shear stress. (See "Management of Marfan syndrome and related disorders", section on 'Restriction of strenuous activity'.)

Screening for genetic conditions — Similar to thoracic aortic aneurysm, patients with thoracic aortic dissection, particularly younger patients less than 60 years of age, should be evaluated for possible underlying genetic or familial disorders known to be related, which may increase their individual risk of progression or complications (algorithm 1) [2,3,5,34]. Screening (transthoracic echocardiography) first-degree family members for aortic aneurysm (or bicuspid aortic valve) should also be considered. (See "Clinical features and diagnosis of acute aortic dissection", section on 'Incidence and associated conditions' and "Management of thoracic aortic aneurysm in adults", section on 'Identifying associated genetic conditions'.)

For patients with aortic root/ascending thoracic aortic aneurysm or dissection, guidelines include the following [5]:

●Obtain a complete family history of any thoracic aortic disease, unexplained deaths, and peripheral or intracranial aneurysm.

●Obtain genetic testing if the patient has risk factors for heritable disease including age <60 years, family history of thoracic aortic disease or intracranial aneurysm, or presence of phenotypic features of genetic aortopathy. For patients with positive genetic testing:

•Obtain cascade testing of at-risk biologic relatives.

•Obtain transthoracic echocardiogram or CT angiography for aneurysm screening in family members with positive genetic testing.

•Provide genetic counseling when screening is positive for aortopathy.

●Screening aortic imaging in family members may be elected if genetic testing was not positive.

Serial imaging — After repair, we generally perform a baseline magnetic resonance (MR) or CT angiography prior to discharge. Following endovascular or open repair in patients with acute aortic dissection or intramural hematoma who have residual aortic disease, surveillance imaging (CT or MR angiography) is recommended at 1 month, 6 months, and 12 months, and if stable, annually thereafter [5]. Most patients have residual dissection in the distal aorta. Risk factors for aortic expansion of distal segments as well as reoperation following type A repair include residual patent false lumen, larger aortic diameters, multiple and large fenestrations, and lack of arch replacement at the initial type A dissection repair [35-37]. (See "Surgical and endovascular management of acute type A aortic dissection", section on 'Reintervention following repair'.)

In addition to multi-view (transthoracic, suprasternal, and abdominal) cardiovascular ultrasonography, MR or CT angiography is warranted for a comprehensive assessment of the aorta and its branches [3,38,39]. MR angiography is considered the technique of choice if not contraindicated, (eg, implanted devices, claustrophobia). MR angiography is as accurate as transesophageal echocardiography (TEE), and because it is noninvasive, it may be is more acceptable for serial studies. MR does not expose patients to iodinated contrast and ionizing radiation, which are important factors for younger patients who will likely have many years of serial monitoring, though due to concerns about long-term retained gadolinium, noncontrast MR angiography is an option that should be considered. CT angiography is an alternative, but uses ionizing radiation and requires iodinated contrast, which may cause nephrotoxicity. Alternating CT and MR angiography is a reasonable option for patients with good renal function. Transthoracic echocardiography is not considered a monitoring alternative, but it may be necessary to monitor ongoing valvular dysfunction.

LONG-TERM SURVIVAL FOLLOWING REPAIR — Due to improvements in operative techniques and perioperative care, in-hospital mortality following repair of type A acute aortic dissection has decreased over time. For those who leave the hospital, the 10-year actuarial survival rate of patients with an acute aortic dissection has ranged from 30 to 90 percent, likely reflecting the population studied. Whether improvements in surgical and medical care have led to better long-term outcomes over time has not been studied.

In an International Registry of Acute Aortic Dissections (IRAD) report of 303 patients with type A dissection, long-term survival after surgical repair of type A dissections at one and three years was 96 and 91 percent, respectively [40]. In a separate study, causes of death in 31 of 380 survivors of an initial type A dissection were stroke (12 patients), aortic reoperation for re-dissection or progressive dilatation of the false lumen (seven patients), malignancy (five patients), myocardial infarction (four patients), and heart failure (three patients) [11].

Longer-term follow-up was provided in a series of 208 patients presenting between 1978 and 1995 [41]. Patient survival at 5 and 10 years was 68 and 52 percent, respectively; residual distal dissected aorta did not affect late survival and had a low risk for aneurysmal change and reoperation.

Long-term survival appears similar for both type A and type B dissections [11,13,14,41-44]. This may be explained by the fact that adverse events, such as recurrent dissection or complications of aneurysm formation in the descending aorta, occur in both type A and type B dissection [45]. Survival is also equally impacted by preexisting medical comorbidities such as ongoing smoking, hypertension, and coronary and peripheral artery disease.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Aortic dissection and other acute aortic syndromes".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Aortic dissection (The Basics)" and "Patient education: Thoracic aortic aneurysm (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Type A aortic dissection – Aortic dissection is defined as a tear in the innermost layer of the aortic wall (ie, intima), which results in high-pressure blood flow between the layers of the aorta, creating a true and false lumen. Type A aortic dissection involves the ascending aorta, regardless of the site of the primary intimal tear (figure 1). Acute type A aortic dissection is a surgical emergency, and patients are at very high risk for early life-threatening complications such as acute aortic regurgitation, cardiac tamponade, and myocardial infarction. (See 'Introduction' above and 'Extent and etiology of dissection' above.)

●Referral and transfer – As soon as acute type A aortic dissection is diagnosed, immediate cardiac surgical consultation is required, and if experienced cardiac surgical services are not available, the patient should be promptly transferred for definitive care. A decision for acute surgical intervention must be tempered with judgement. An experienced cardiovascular surgeon should be involved early in the course to discuss any decision for surgery and its timing, which must be individualized accounting for the patient's clinical condition, age, comorbidities, and patient and family wishes. (See 'Surgical referral or transfer' above and 'Decision for comfort care' above.)

●Acute medical management – Acute medical management of acute type A aortic dissection involves controlling pain and providing anti-impulse therapy to minimize the tendency for the dissection to propagate (table 2 and table 3). Initial medical treatment of acute aortic dissection should not interfere with the timely transfer to the operating room for immediate aortic repair in patients with acute type A aortic dissection or transfer to another hospital, if needed. (See 'Acute management' above.)

●Preoperative imaging – Cardiovascular imaging is necessary to confirm the diagnosis of type A aortic dissection and to evaluate the extent of the dissection. Even if there is concern for coronary artery disease of involvement due to the dissection, pursuing preoperative coronary angiography for patients with acute type A aortic dissection is of limited value; the resulting delay of surgery for type A aortic dissection increases the risk for complications. (See 'Imaging evaluation' above.)

●Extent of surgical repair – When the aortic valve, sinuses, or arch are involved, the surgical approach involves a full aortic root or hemiarch replacement. A hybrid approach to the repair of type A aortic dissection, sometimes referred to as the "frozen elephant trunk repair," uses an open surgery to repair the ascending aorta and a thoracic endograft to manage the descending aorta. (See "Overview of open surgical repair of the thoracic aorta", section on 'Ascending aorta'.)

●Long-term management – Following repair of acute type A aortic dissection, the patient should be maintained on anti-impulse therapy to minimize aortic wall stress with a target blood pressure of less than 120/80 mmHg. Prior to discharge, MR or CT angiography should be performed and lifelong annual cardiovascular imaging surveillance is obtained to detect signs of progression of the dissection, new dissection, or aneurysm formation, even if the patient remains asymptomatic.

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Emile R Mohler, III, MD (deceased), who contributed to an earlier version of this topic review.