1.
Study Population and Definitions
A total of 2133 consecutive cases of type A acute aortic dissection (AD) or intramural hematoma (IMH) were diagnosed by CT in Beijing Fuwai Hospital from January 2010 to December 2017.
264 cases of them were pulmonary artery involvement by CT retrospective diagnosis.
Acute aortic Syndrome(AAS) is defined as 14 days or fewer from symptom onset[7].
Classic AD was defined as the dissection with visible intimal tear and flow communication between true and false lumen.
IMH was defined as a crescentic or circular high-attenuation area along the aortic wall without contrast enhancement in CT.[8]
Study approval was obtained from the Internal Review Board of Fuwai Hospital.
2.
Research methods and scanning technique
A multi-slice spiral CT scanner was used,
and a continuous volume-enhanced scan without cardiac gating was used for the aorta.
All patients were in supine position,
arms were lifted,
and the scanning direction is from the head side to the foot side.
The scanning range was generally from the thoracic inlet to common iliac Bifurcation level.
The automatic contrast agent tracking technology is used in the scan,
and the region of interest is placed at the level of the descending aorta,
and the threshold for triggering scan is set to 150 to 250HU (the threshold is different according to different models),
then the scan is automatically or manually triggered.
A concentration of 300-370 mg I/ml contrast agent was injected through cubital fossa vein,
the total amount was 50-80 mL,
the injection flow rate was 4.0 mL/s,
and 40 mL normal saline was added for washing.
3.
Diagnosis of pulmonary artery involvement
When the pulmonary artery wall is involved,
the hematoma spreads along the pulmonary artery wall,
resulting in a moderate density thickening.
The hematoma can spread along the central pulmonary artery to the hilar or segmental vessels.
When the hematoma is large,
the pulmonary artery wall is stiff,
losing a streamlined shape,
and even cause pulmonary artery stenosis by compresses.
In addition,
there is a hematoma gap between the ascending aorta and the pulmonary artery.
The visible image of intimal flap in pulmonary artery can be used to diagnose a pulmonary dissection.
(Fig.
A-D)
4.
Treatment
Surgical treatment is preferred for patients with type A aortic dissection.
Conservative treatment is used for type A intramural hematoma patients without obvious ulcer.
Patients with critical hemodynamics situation or patients who refuse surgery should use conservative symptomatic treatment and antihypertensive treatment.
The reported reasons for non-surgical treatment were advanced age,
comorbidity,
patient refusal,
and death prior to planned surgery.
In this study,
129 patients received conservative treatment and 135 patients underwent surgical treatment.