Aortic Remodeling Following Sun's Procedure for Acute Type A Aortic Dissection

Automatic segmentation of thrombosed aortic dissection in post-operative CT-angiography images

PURPOSE

The thrombus in the false lumen (FL) of aortic dissection (AD) patients is a meaningful indicator to determine aortic remodeling but difficult to measure in clinic. In this study, a novel segmentation strategy based on deep learning was proposed to automatically extract the thrombus in the FL in post-operative computed tomography angiography (CTA) images of AD patients, which provided an efficient and convenient segmentation method with high accuracy.

METHODS

A two-step segmentation strategy was proposed. Each step contained a convolutional neural network (CNN) to segment the aorta and the thrombus, respectively. In the first step, a CNN was used to obtain the binary segmentation mask of the whole aorta. In the second step, another CNN was introduced to segment the thrombus. The results of the first step were used as additional input to the second step to highlight the aorta in the complex background. Moreover, skip connection attention refinement (SAR) modules were designed and added in the second step to improve the segmentation accuracy of the thrombus details by efficiently using the low-level features.

RESULTS

The proposed method provided accurate thrombus segmentation results (0.903 ± 0.062 in dice score, 0.828 ± 0.092 in Jaccard index, and 2.209 ± 2.945 in 95% Hausdorff distance), which showed improvement compared to the methods without prior information (0.846 ± 0.085 in dice score) and the method without SAR (0.899 ± 0.060 in dice score). Moreover, the proposed method achieved 0.967 ± 0.029 and 0.948 ± 0.041 in dice score of true lumen (TL) and patent FL (PFL) segmentation, respectively, indicating the excellence of the proposed method in the segmentation task of the overall aorta.

CONCLUSIONS

A novel CNN-based segmentation framework was proposed to automatically obtain thrombus segmentation for thrombosed AD in post-operative CTA images, which provided a useful tool for further application of thrombus-related indicators in clinical and research application.

Volumetric Measurements Improve the Accuracy of Aortic Remodeling Prediction in Aortic Dissection

Accessing aortic remodeling status through regular follow-ups is essential for acute type A aortic dissection patients undergone surgical treatment. Aortic remodeling status was usually determined using diameter or area measurements of the true and false lumen in specific anatomical slices of medical images. However, these indicators only represent partial information about the aorta and can hardly characterize the overall aorta situation. In this study, we included two types of morphology features collected from computed tomography angiography images to predict the aortic remodeling. One type is the volumetric measurements of the true and false lumen, which provide a better overall description of the aorta, and the other type is the volumetric measurements of the thrombus in false lumen and the patent false lumen, which present more detailed information of the dissection. Through progressively incorporating these measurements into the construction of the remodeling prediction model, we investigated the importance of the features that describe the overall situation and that characterize aortic internal details in remodeling prediction, especially the effect of quantitative thrombosis features. The results showed that with the inclusion of the two types of volume features, the prediction accuracy of the model increased, which proves that volumetric measurements of aortic dissection, especially the volume of thrombus, are of significant value in aortic remodeling prediction, and should be paid more attention on in clinical practice and research areas. Clinical Relevance-Demonstrating the importance of volumetric measurements of true and false lumen thrombus in false lumen and patent false lumen in the prediction of aortic remodeling.

Application of interventional embolization in the treatment of iatrogenic pseudoaneurysms

The present study aimed to investigate the clinical effectiveness and safety of endovascular embolization for the treatment of pseudoaneurysm secondary to previous abdominal and pelvic surgery or radiological percutaneous abdominal procedure. A retrospective review was performed on all patients with abdominal and pelvic pseudoaneurysm confirmed by CT angiography or digital subtraction angiography and treated with endovascular embolization. Different techniques of embolization with coils were applied and the outcomes, including clinical effectiveness and safety, were assessed. A total of 31 patients with a total of 32 pseudoaneurysms were included in the present study. Of these pseudoaneurysms, 23 were from the main trunks and branches of the gastroduodenal artery, 5 were from the splenic artery, 2 were from the common hepatic artery, 1 was from the right hepatic artery and 1 was from the right internal iliac artery. There were no serious complications observed and there was no occurrence of re-bleeding following embolization. The embolization of the pseudoaneurysms was successful in all patients. In conclusion, endovascular embolization is a safe and effective method for the treatment of secondary iatrogenic pseudoaneurysm in the abdomen and pelvis.

Carotid Artery Stenting for the Treatment of Fatal Acute Cerebral Infarction Associated with Aortic Dissection

Acute aortic dissection (AAD) complicated with acute cerebral infarction lacks a unified treatment plan. We report probably the most effective treatment of a type A AAD with acute cerebral infarction leading to coma. A 43-year-old man presented with acute hemiplegia and unconsciousness. He was diagnosed as acute cerebral infarction. After an ineffective emergency intravenous thrombolysis, a Digital Subtraction Angiography (DSA) examination revealed the severe cerebral artery occlusion, and the TICI 3 level was achieved by stent implantation in the left common carotid artery with significant neurological recovery. A type A AAD was found at the 1 month follow-up ultrasound examination and a further thoracic surgery was performed successfully. Carotid ultrasound is helpful for the diagnosis of AAD from acute cerebral infarction. Carotid artery stenting followed by thoracic surgery is effective in this kind of emergency situations. Further studies are needed to determine the exact indications.

"Aorta-clamp" technique for surgical repair of acute type A aortic dissection-5 min circulatory arrest at 30 °C

Background

Deep hypothermic circulatory arrest (HCA), which causes perioperative complications, is the foundation of surgical treatment for acute type A aortic dissection (AAAD). To extensively replace the dissected aorta and avoid the negative impacts of HCA, we developed an "aorta-clamp" technique and examined its efficacy in repairing AAAD.

Methods

From November 2014 to August 2016, we recruited 59 consecutive patients (51.3±10.9 years) with AAAD into this study. We performed total arch replacement combined with an elephant trunk implantation using the "aorta-clamp" technique under a 30 °C HCA with continual bilateral antegrade cerebral perfusion.

Results

The average HCA time was 4.9±1.0 min. Twenty-three patients had increased serum creatinine (sCr) before surgery, suggesting an AAAD-associated acute kidney injury (AKI). The sCr level returned to normal in five patients after operation and in 15 before discharge. Six patients (10.2%) with preoperative AKI required postoperative dialysis, and two of these patients (3.4%) died of multiple organ failure. Two patients (3.4%) required re-exploration due to bleeding. One patient (1.7%) exhibited temporary neurologic deficits. There were no late deaths. Computed tomography (CT) examination confirmed the patency of the anastomotic sites and thrombus obliteration of the residual false lumen.

Conclusions

Using the "aorta-clamp" technique with continual bilateral antegrade cerebral perfusion, total arch replacement combined with an elephant trunk implantation can be performed under five minutes of mild (30 °C) HCA. Our data suggest that this technique for the surgical repair of AAAD is a safe, feasible and effective surgical approach with satisfactory early outcomes.

Factors Associated with Low Admission Platelet Count in Adults with Acute Aortic Dissection

Purpose: Platelets are crucial components of the coagulation processes, and low admission platelet count (PLC) is associated with adverse clinical outcomes in patients with Stanford type A acute aortic dissection (AAD).

Methods: A total of 130 consecutive patients undergoing Stanford type A AAD surgery in Beijing Anzhen Hospital were enrolled between January 2013 and July 2014. Preoperative clinical and laboratory data from patients were collected. Multiple regression analyses were used to determine the independent factors of low admission platelets.

Results: Adjusted multiple regression analysis showed that age (β: −1.069, 95% confidence interval [CI]: −2.109, −0.029), sex (β: −29.973, 95% CI: −56.512, −3.433), tissue factor pathway inhibitor (TFPI; β: 0.197, 95% CI: 0.039, 0.354), fibrinogen degradation product (FDP) (β: −0.476, 95% CI: −0.879, −0.074), and attack time (β: 11.125, 95% CI: 7.963, 14.287) were significantly associated with admission PLC. Admission PLC increased with attack time up to the 3 days (β: 16.2, 95% CI: 12.1, 20.2).

Conclusions: We found that increasing age, male patients, patients with lower serum levels of TFPI and higher serum levels of FDP, and patients with a shorter attack time were significantly associated with lower PLC at admission. Moreover, the turning point of attack time is 3 days after the onset of dissection.

Efficacy of Total Aortic Arch Replacement Combined with Frozen Elephant Trunk in Aortic Reoperation

Background

The aim of this study was to estimate the long-term efficacy of total aortic arch replacement combined with the frozen elephant trunk (TAR+FET) technique for aortic disease following a prior cardiac surgery procedure.

Material/Methods

We performed TAR+FET for 118 patients for major vessel disease following a prior cardiac procedure with median sternotomy incision. All patients were divided into 5 groups: in group A, the prior major procedure was aortic valve replacement (AVR); in group B, the prior major procedure was isolated ascending aorta replacement; in group C, the prior major procedure was aortic root replacement; in group D, the prior major procedure was aortic arch replacement or intervention; and in group E, the prior major procedure was ‘other’ cardiac operative procedure. The long-term follow-up visit results were estimated using the Kaplan-Meier method.

Results

The 30-day mortality rate after the operation was 13.6% (16/118) – 2 died in group A, 1 in group B, 8 in group C, 4 in group D, and 1 in group E. Follow-up visits were completed in 99% of patients. The mean follow-up time was 47.6±36.3 months and 12 patients had died by follow-up, so the total long-term survival rate was 76.3%. One-year survival rates of the 5 groups were 85% (group A), 93.8% (group B), 82.3% (group C), 50% (group D), and 50% (group E), respectively. Five-year survival rates of the 5 groups were 85%, 93.8%, 80.6%, 50%, and 50%, respectively.

Conclusions

The TAR+FET technique is feasible and efficacious for aortic reoperation in patients who previously underwent cardiac surgery since the short-term mortality in patients with recurrent aortic arch disease after cardiac surgery is not high.