[Value of contrast-enhanced ultrasonography in detection of endoleak after endovascular repair of infrarenal abdominal aortic aneurysm].

Abstract

Objective: To investigate the value of contrast-enhanced ultrasound in detecting endoleak after endovascular repair of infrarenal abdominal aortic aneurysm (EVAR). Methods: The postoperative follow-up data of 102 patients with infrarenal abdominal aortic aneurysm treated with EVAR in Tianjin Medical University General Hospital from August 2015 to December 2021 were retrospectively analyzed. There were 79 males and 23 females, aged 50-91 (69.6±7.6) years old. Using CT angiography (CTA) as the gold standard for diagnosing endoleaks, the effectiveness of contrast-enhanced ultrasound and CDUS in detecting endoleaks was evaluated by paired design chi-square test, and the Kappa value was calculated for consistency test. Patients were divided into groups according to body mass index (BMI), and the number of false-negative endoleaks detected by contrast-enhanced ultrasound in each group was calculated, and its ratio to the actual number of endoleaks was calculated to evaluate whether BMI was related to false-negative ultrasound-enhanced ultrasound. Results: A total of 203 follow-up visits met the inclusion criteria. Endoleaks were detected 36 times (17.7%) by CTA, 31 times (15.3%) by contrast-enhanced ultrasound, 16 times (7.9%) by CDUS, and they all detected type Ⅰ, type Ⅱ and type Ⅲ endoleaks. There was no significant difference between contrast-enhanced ultrasound and CTA in endoleak detection rate and determination of endoleak types (endoleak detection rate: 15.3% vs 17.7%; determination of endoleak types: type Ⅰ 4 vs 4, type Ⅱ 26 vs 31, type Ⅲ 1 vs 1; all P>0.05). CDUS and CTA had statistically significant differences in the detection rate of endoleaks and determination of endoleak types (endoleak detection rate: 7.9% vs 17.7%; determination of endoleak types: type Ⅰ 4 vs 4, type Ⅱ 11 vs 31, type Ⅲ 1 vs 1; all P<0.001). Compared with CTA, contrast-enhanced ultrasound has a sensitivity of 83.3%, a specificity of 99.4%, a Youden index of 0.827, a coincidence rate of 96.6%, a positive predictive value of 96.8%, a negative predictive value of 96.5%, and a Kappa value of 0.875(P<0.001). The two showed excellent diagnostic consistency. All 6 endoleaks not detected by contrast-enhanced ultrasound were type Ⅱ endoleak that did not require treatment, and 3(15.8%) occurred in obese patients with a BMI≥32 kg/m2. Compared with CTA, CDUS had a sensitivity of 38.9%, a specificity of 98.8%, a Youden index of 0.377, a coincidence rate of 88.2%, a positive predictive value of 87.5%, a negative predictive value of 88.2%, and a Kappa value of 0.482 (P<0.001). The two showed moderate diagnostic agreement. The correlation coefficient of the maximum diameter of aneurysms measured by ultrasound and CT was r=0.873(P<0.001). Conclusions: Contrast-enhanced ultrasound is accurate in detecting endoleak after infrarenal EVAR, and its sensitivity to endoleak detection in obese patients with BMI≥32 kg/m2 will be reduced. CDUS is not suitable for detection of endoleak after infrarenal EVAR, but it can be used to monitor the change of the largest diameter of aneurysm after EVAR.