7 types of differential diagnosis methods for aortic dissection

Aortic dissection is a serious and complicated disease. To diagnose aortic dissection, a comprehensive examination and systematic analysis are needed to differentiate and diagnose the final result. Some symptoms of aortic dissection are similar to those of acute myocardial infarction, which can easily lead to misdiagnosis. Therefore, when monitoring aortic dissection, it is important to ensure that all monitoring is in place.

1. Electrocardiogram

Aortic dissection itself has no specific ECG changes. Those with a history of hypertension may have left ventricular hypertrophy and strain; when the coronary arteries are affected, ECG changes of myocardial ischemia or myocardial infarction may occur; when there is pericardial effusion, ECG changes of acute pericarditis may occur.

2. Chest X-ray

In recent years, various imaging diagnostic methods have received increasing attention and have been widely used in the diagnosis of aortic dissection. However, according to clinical diagnosis and treatment requirements, plain X-rays should be used as a routine diagnosis of aortic diseases. Thoracic aortic aneurysm and chronic aortic dissection may be discovered incidentally on plain radiographs.

3. Echocardiography and Doppler

Two-dimensional echocardiography has important clinical value in diagnosing ascending aortic dissection. It is very reliable for observing the swinging intimal flap separation in the aorta and the true and false double-chamber sign of the aorta in aortic dissection. It can also show aortic root dilatation, aortic wall thickening and aortic valve insufficiency, and it is easy to identify complications such as pericardial effusion and thoracic hemorrhage.

4. Computed tomography (CT)

CT can show dilatation of the diseased aorta and is better than X-ray in detecting aortic intimal calcification. If the calcified intima shifts toward the center, it indicates aortic dissection; if it shifts toward the periphery, it indicates simple aortic aneurysm. Because it scans perpendicular to the longitudinal axis of the aorta, it is easier to detect vertical intimal tears than arteriography.

5. Magnetic resonance imaging (MRI)

The effects of MRI and CT are similar, but compared with CT, it can perform multi-directional, multi-parameter imaging in the transverse axial, sagittal, coronary and left anterior oblique planes, and can comprehensively observe the type and range of lesions and anatomical changes without the use of contrast agents. Its diagnostic value is better than that of Doppler ultrasound and CT, and its specificity and sensitivity for diagnosing aortic dissection are both over 90%. Especially when the aortic dissection is spirally torn and reaches the abdominal aorta, it can still directly display the true and false lumens of the aortic dissection, and more clearly show the location of the intimal tear and the relationship between the lesion and the aortic branches. Its disadvantages are high cost, it cannot be used for patients with pacemakers or with metal objects such as nodes and needles, and it cannot satisfactorily display the condition of the coronary artery and aortic valve.

6. Digital Subtraction Angiography (DSA)

Less invasive intravenous DSA can basically replace conventional angiography for the diagnosis of type B aortic dissection. It can correctly detect the location and extent of aortic dissection, aortic hemodynamics and perfusion of main branches. In some patients, torn intimal sheets can be clearly seen on DSA, and calcification that cannot be detected by aortic angiography can be easily found. However, for ascending aortic dissection of type A or Marfan syndrome, venous DSA has its limitations and poor resolution, and subtle structures such as intimal tears that can be detected by conventional arteriography may be missed.

7. Aortography

Currently, the method of transarterial retrograde catheterization is mostly used. Its greatest advantage is that it can confirm the entrance and exit of the intimal tear, clarify the involvement of the aortic branches, and estimate the severity of aortic valve regurgitation. Most surgeons still believe that aortic angiography is essential when establishing a diagnosis and formulating a surgical plan.