How should a patient with suspected acute aortic dissection be initially managed, including hemodynamic stabilization, medication choices, imaging, and surgical decision-making?

Management of Acute Aortic Dissection

Immediately initiate intravenous beta-blocker therapy to achieve a heart rate ≤60 beats per minute BEFORE adding any vasodilator, then target systolic blood pressure 100-120 mmHg, obtain urgent CT angiography for diagnosis, and activate cardiac surgery immediately for all Type A dissections. 1, 2

Immediate Hemodynamic Stabilization

Heart Rate Control (First Priority)

• Start intravenous beta-blockers immediately as first-line therapy to target heart rate ≤60 beats per minute, using esmolol (loading dose 500 mcg/kg over 1 minute, then 50-200 mcg/kg/min infusion) or labetalol (20 mg IV bolus, then 40-80 mg every 10 minutes up to 300 mg total, or 0.5-2 mg/min infusion). 1, 2, 3

• Labetalol is preferred due to its combined alpha- and beta-blocking properties, providing both rate and blood pressure control simultaneously. 2

• If beta-blockers are contraindicated (severe asthma, decompensated heart failure, high-degree AV block), use non-dihydropyridine calcium channel blockers (diltiazem or verapamil) for rate control instead. 1, 2, 3

Blood Pressure Control (Second Priority)

• Only after achieving adequate heart rate control, add intravenous vasodilators if systolic blood pressure remains >120 mmHg, using nicardipine (5 mg/hr initially, titrate by 2.5 mg/hr every 5-15 minutes to maximum 15 mg/hr) or sodium nitroprusside (0.3-0.5 mcg/kg/min initially, titrate to effect). 1, 2, 3

• Target systolic blood pressure 100-120 mmHg and diastolic <80 mmHg to reduce aortic wall stress. 1, 2, 3

• Never initiate vasodilator therapy before rate control, as this causes reflex tachycardia that increases aortic wall stress and can propagate the dissection—this is a Class III (harm) recommendation. 1, 3

Monitoring Requirements

• Establish invasive arterial line monitoring for accurate continuous blood pressure measurement. 2

• Place continuous three-lead ECG monitoring. 2

• Secure intravenous access and obtain blood samples for complete blood count, serum chemistries, coagulation profiles, and type and crossmatch. 1

• Provide adequate analgesia with morphine sulfate to control pain and reduce sympathetic surge. 2

• Transfer immediately to intensive care unit for appropriate monitoring. 2

Diagnostic Imaging

Primary Imaging Modality

• Obtain urgent CT angiography of the entire aorta (from aortic sinus through iliac bifurcation) as the first-line diagnostic test, as it provides 100% sensitivity and 98% specificity, is rapidly available 24/7, and shows the full extent of dissection, entry tear sites, branch vessel involvement, and complications. 2, 4

• Use ECG-gated acquisition to reduce motion artifacts, with non-enhanced CT followed by contrast-enhanced angiography as the optimal protocol. 4

• Do not delay definitive imaging in high-risk patients even if chest x-ray is negative, as chest x-ray has only 60-80% sensitivity for Type A dissection. 1, 2

Alternative Imaging

• Consider transesophageal echocardiography (TEE) when the patient is too unstable to transport to radiology, has contraindications to iodinated contrast, or requires rapid bedside assessment—TEE has 98-100% sensitivity and 95-100% specificity. 1, 2, 4

• If high clinical suspicion exists but initial imaging is negative, obtain a second imaging study with a different modality. 1

• Transthoracic echocardiography (TTE) alone should never be relied upon to definitively establish or exclude the diagnosis, as it has only 60-80% sensitivity for Type A dissection. 1

Surgical Decision-Making

Type A Dissection (Ascending Aorta)

• Obtain urgent surgical consultation immediately upon diagnosis or high suspicion, and proceed directly to emergency surgical repair without delay. 1, 2

• Type A dissection is a surgical emergency with 1-2% mortality per hour if untreated, requiring replacement of the ascending aorta with or without aortic root or arch replacement to prevent aortic rupture, pericardial tamponade, and relieve aortic regurgitation. 2, 5

• Consider direct admission to the operating room with intraoperative TEE confirmation rather than delaying for additional imaging, as this strategy has been shown to improve survival by expediting intervention and reducing risk of aortic rupture. 6, 7

• Avoid routine coronary angiography before surgery, as it delays intervention and increases mortality from aortic rupture—coronary angiography documented disease in only 11% of patients and failed to reveal disease in others who died. 7

Type B Dissection (Descending Aorta)

• Initially manage Type B dissection medically with aggressive blood pressure and heart rate control unless complicated. 2

• Proceed to emergency intervention (preferably thoracic endovascular aortic repair/TEVAR) for complicated Type B dissection presenting with: 2

  • Malperfusion syndrome (visceral, renal, or limb ischemia)
  • Intractable pain despite adequate medical therapy
  • Rapidly expanding aortic diameter
  • Periaortic or mediastinal hematoma
  • Dissection occurring in a previously aneurysmal aorta

Special Considerations for Malperfusion

• In Type A dissection with peripheral malperfusion, consider percutaneous revascularization first before surgical repair to allow ischemic injury to resolve, as 30-day mortality is largely dependent on severity and duration of ischemia. 2

• In cases of malperfusion, higher blood pressure may be tolerated (up to 140 mmHg systolic) to optimize perfusion to the threatened region. 2

Critical Pitfalls to Avoid

• Beta-blockers should be used cautiously in acute severe aortic regurgitation, as they block the compensatory tachycardia needed to maintain cardiac output—however, do not withhold entirely, just use lower doses and monitor closely. 1

• Intra-aortic balloon counterpulsation is absolutely contraindicated in acute aortic regurgitation from dissection. 1

• Do not administer antithrombotic therapy (aspirin, heparin, thrombolytics) in suspected aortic dissection, as this increases risk of hemorrhage and aortic rupture. 1

• If ST-segment elevation is present on ECG, treat as primary cardiac event (STEMI) without delay for aortic imaging UNLESS the patient has high-risk features for dissection (sudden tearing chest/back pain, pulse deficits, blood pressure differentials >20 mmHg between arms, mediastinal widening on chest x-ray). 1

Transfer and Activation Protocols

• Transfer all patients with suspected aortic dissection (ADD score ≥1) to a center with 24/7 available aortic imaging and cardiac surgery. 1

• Consider activating aortic imaging and cardiac surgery teams for direct admission to radiology before proceeding to the operating room. 1

• Use the ADD (Aortic Dissection Detection) risk score in the pre-hospital and emergency department setting to identify high-risk patients requiring immediate imaging and surgical consultation. 1