What is the next best investigation to confirm the diagnosis in a patient with severe chest pain radiating to the back and acute stroke symptoms?

Next Best Investigation: Contrast CT of the Chest

In this patient presenting with severe chest pain radiating to the back followed by acute stroke symptoms, contrast CT angiography of the chest (extending to abdomen and pelvis) should be ordered immediately to diagnose acute aortic dissection. 1

Clinical Reasoning

This presentation is classic for acute aortic dissection with embolic stroke as a complication:

• Severe chest pain radiating to the back occurring 15 minutes before stroke onset is a hallmark feature of aortic dissection, described as "ripping or tearing" in quality 1
• Acute stroke symptoms (aphasia, right hemiparesis) occur in 18-30% of aortic dissections due to cerebral ischemia from arterial involvement or embolization 2, 3
• Hypertension and smoking are prominent risk factors for acute aortic syndrome 1
• Hemodynamic instability (tachycardia 122, elevated BP 173/100) with cool skin and diaphoresis suggests cardiovascular catastrophe 1

Why Contrast CT of the Chest is the Answer

CT angiography is the diagnostic modality of choice for stable patients with suspected aortic dissection, with both high sensitivity and specificity 1. The 2021 ACC/AHA guidelines give this a Class 1 recommendation for diagnosis and treatment planning 1.

• CT can rapidly image the entire aorta from arch through abdomen/pelvis to assess dissection extent and involvement of branch vessels 1
• Timing is critical: This patient needs immediate diagnosis before any consideration of thrombolytic therapy for stroke, as administering tPA to an aortic dissection patient carries a 71% mortality rate 2, 3
• CT is more expeditious than other modalities like MRI or TEE in the acute setting 1

Why Other Options Are Incorrect

B. Transthoracic echocardiography - While TTE can show pericardial effusion, aortic regurgitation, or occasionally visualize a dissection flap in the ascending aorta, it cannot adequately image the aortic arch and descending aorta where dissection commonly extends 1. The European Society of Cardiology notes that echocardiography is "of particular value for diagnosis of other causes of chest pain such as acute aortic dissection" 1, but this refers to its supportive role, not as the primary diagnostic test. Complete imaging requires CT or TEE 1.

C. Troponin - While troponin elevation can occur with aortic dissection involving coronary ostia, waiting for troponin results delays definitive imaging and does not establish the diagnosis of dissection 1. The guidelines explicitly state "one should not wait for the results to initiate reperfusion treatment" in MI contexts 1, and similarly, one should not wait for biomarkers when aortic dissection is suspected clinically.

D. Urine drug screen - Although cocaine can provoke dissection even without other risk factors 1, a drug screen does not diagnose the acute pathology and would inappropriately delay life-saving imaging and surgical intervention.

Critical Pitfalls to Avoid

• Do not assume stroke symptoms rule out aortic dissection: Up to 30% of dissection patients present with neurologic deficits, and many have no chest pain complaint 2, 3
• Do not administer thrombolytics before excluding dissection: Point-of-care ultrasound or rapid CT must be performed first in patients with stroke and atypical features 2
• Look for subtle clues: Low systolic blood pressure in one arm (≤110 mmHg) and elevated D-dimer (≥5.0 μg/ml) have high predictive value for dissection in stroke patients 3
• Chest X-ray may be normal: Mediastinal widening is not always present, so negative chest radiography does not exclude dissection 1

Immediate Management Implications

Once aortic dissection is confirmed on CT, this patient requires:

• Immediate cardiovascular surgery consultation for Type A dissection repair 1
• Blood pressure control to prevent dissection extension
• Avoidance of anticoagulation or thrombolytics which would be catastrophic 2, 3

The combination of severe back pain preceding stroke in an elderly hypertensive patient creates a high pretest probability for aortic dissection that mandates urgent CT angiography 1, 3.