Diagnosis
Recently, various tests have been helpful in establishing aortic coarctation. Echocardiography, CT scan, MRI can be used for diagnosis, and aortogram is still necessary for those considering surgery.
The diagnosis of aortic coarctation can be confirmed by
(a) Electrocardiogram
It can show left ventricular hypertrophy and non-specific ST-T changes. If the lesion involves the coronary artery, acute myocardial ischemia or even acute myocardial infarction may be seen. The ECG changes of acute pericarditis can be seen in case of pericardial blood accumulation.
(B) X-ray
Chest plain film shows enlarged superior mediastinum or aortic arch shadow, irregular shape of aorta with localized elevation. The thickness of the aortic wall can be accurately measured if calcified intimal shadows are seen. It is normal at 2 to 3 mm, and an increase to 10 mm suggests the possibility of entrapment separation, and if it exceeds 10 mm, the disease is definitely present. Aortography can show the site of the cleft, clarify the involvement of branches and aortic valves, and estimate the severity of aortic valve closure insufficiency. The disadvantage is that it is an invasive test and involves some intraoperative risk, while CT can show the dilatation of the diseased aorta. The detection of intimal calcification in the aorta is better than on radiographs. If the calcified intima is displaced centrally, it indicates aortic coarctation, while if it is displaced peripherally, it indicates simple aortic aneurysm. In addition, CT can show an endothelial flap due to endothelial tear of the aorta, which divides the aortic coarctation into a true lumen and a false lumen.CT is highly accurate in separating the descending aortic coarctation, and the ascending and arch segments of the aorta can produce false positives or false negatives due to arterial torsion. However, CT has difficulty in determining the site of the fissure and the condition of the aortic branch vessels and cannot estimate the presence of aortic valve closure insufficiency.
Application of CT in the diagnosis of aortic coarctation
(C) Echocardiography
It is important in the diagnosis of ascending aortic coarctation separation and easy to identify complications (such as pericardial hemorrhage, aortic valve insufficiency and pleural hemorrhage). In M-mode ultrasound, the aortic root is seen to be enlarged and the aortic wall at the site of the intercalated separation changes from a normal single echogenic band to two separated echogenic bands. In two-dimensional ultrasound, the endothelial piece of intra-aortic separation is seen as the endothelial oscillation sign, and the aortic sandwich separation forms the true and false double lumen sign of the aorta. Sometimes pericardial or pleural effusion is seen. Doppler ultrasound is not only able to detect abnormal blood flow between the double echoes in the wall of the separated aortic sandwich, but also has important diagnostic value for the typing of aortic sandwich, localization of the breach and quantitative analysis of aortic valve regurgitation. Application of esophageal echocardiography. Combined with real-time color flow imaging technique, it is more reliable to observe the separated lesion of ascending aortic coarctation. It also has a high specificity and sensitivity for descending aortic coarctation.
(iv) Magnetic resonance imaging (MRI)
MRI can directly show the true and false lumen of aortic coarctation, and clearly show the location of endothelial tear and peeled endothelial piece or thrombus. It can determine the extent and staging of the entrapment, as well as the relationship with the aortic branches. However, its shortcomings are high cost, inability to directly detect aortic valve closure insufficiency, and inability to be used in patients with pacemakers and metal objects with artificial joints and steel needles.
(E) Digital subtraction angiography (DSA)
Non-invasive DSA is more accurate for the diagnosis of type B aortic dissection and can reveal the location and extent of the dissection and sometimes the torn endothelial fragments, but it is less valuable for the diagnosis of type A lesions. DSA can also show the hemodynamics of the aorta and the perfusion of the major branches. It is easy to detect calcifications that cannot be detected by angiography.
(vi) Blood and urine tests Leukocyte count
Often increases rapidly. Hemolytic anemia and jaundice may be present. Red blood cells may be present in the urine, even in sarcoid hematuria.
Differentiation
Acute onset of severe chest pain, high blood pressure, sudden aortic valve insufficiency, unequal pulses on both sides or palpable pulsatile masses should be considered for this condition. Chest pain is often considered as acute myocardial infarction, but in myocardial infarction, the chest pain is not very severe at the beginning, gradually worsens, or worsens again after it is reduced, does not radiate below the chest, can be effective with painkillers, accompanied by characteristic changes in the electrocardiogram, if the appearance of shock, the blood pressure is often low, and does not cause unequal pulses on both sides, the above points are sufficient to differentiate.
Examination and laboratory tests
1.Electrocardiogram There are no specific electrocardiogram changes in aortic coarctation itself. In case of hypertension, there may be left ventricular hypertrophy and strain; in case of coronary artery involvement, there may be myocardial ischemia or myocardial infarction ECG changes; in case of pericardial blood accumulation, there may be ECG changes of acute pericarditis.
In recent years, various diagnostic imaging methods have been paid more and more attention and are widely used to diagnose aortic coarctation, but according to the requirements of clinical diagnosis and treatment, X-ray plain film should be used as a routine diagnosis of aortic disorders.
3.Echocardiography and Doppler Two-dimensional echocardiography has important clinical value for the diagnosis of ascending aortic coarctation. It is very reliable for observing the oscillation of the endothelial sheet separated in the aorta and the true and false double lumen sign of the aorta in aortic coarctation, and it can see the aortic root dilatation, aortic wall thickening and incomplete aortic valve closure, and it is easy to identify the complications, such as pericardial hemorrhage and thoracic hemorrhage.
4.Computed tomography (CT) CT can show the dilatation of the diseased aorta and find the aortic intimal calcification better than X-ray plain film. If the calcified intima is displaced to the center, it suggests aortic coarctation, and if it is displaced to the periphery, it suggests simple aortic aneurysm.
5.Magnetic resonance imaging (MRI) MRI is similar to CT, but compared with CT, it can be multi-directional and multi-parameter imaging in transaxial, sagittal, coronal and left anterior oblique positions, and it can comprehensively observe the type and scope of lesions and anatomical changes without using contrast, and its diagnostic value is better than Doppler ultrasound and CT.
6.Digital subtraction angiography (DSA) Less invasive intravenous DSA can basically replace common arteriography in the diagnosis of B-type aortic coarctation.
7.Aortography At present, the method of retrograde cannulation through arteries is mostly used. The biggest advantage is that it can confirm the entrance and exit of endothelial tears, clarify the involvement of aortic branches, and estimate the severity of aortic valve insufficiency, etc. Most surgeons still think that aortography is essential in establishing the diagnosis and making surgery plans.
8. Blood and urine tests The white blood cell count often increases rapidly. Hemolytic anemia and jaundice may occur. There may be red blood cells in the urine or even hematuria in the eyes.