Acute type A aortic intramural hematoma and type A aortic dissection: correlation between the intimal tear features and pathogenesis

Acute type a aortic intramural hematoma complicated with preoperative hemopericardium: early and late surgical outcome analyses

BACKGROUND

Acute type A aortic intramural hematoma (ATAIMH) is a variant of acute type A aortic dissection (ATAAD), exhibiting an increased risk of hemopericardium and cardiac tamponade. It can be life-threatening without emergency treatment. However, comprehensive studies of the clinical features and surgical outcomes of preoperative hemopericardium in patients with ATAIMH remain scarce. This retrospective study aims to investigate the clinical features and early and late outcomes of patients who underwent aortic repair surgery for ATAIMH complicated with preoperative hemopericardium.

METHODS

We investigated 132 consecutive patients who underwent emergency ATAIMH repair at this institution between February 2007 and August 2020. These patients were dichotomized into the hemopericardium (n = 58; 43.9%) and non-hemopericardium groups (n = 74; 56.1%). We compared the clinical demographics, surgical information, postoperative complications, 5-year cumulative survival rates, and freedom from reoperation rates. Furthermore, multivariable logistic regression analysis was utilized to identify independent risk factors for patients who underwent re-exploration for bleeding.

RESULTS

In the hemopericardium group, 36.2% of patients presented with cardiac tamponade before surgery. Moreover, the hemopericardium group showed higher rates of preoperative shock and endotracheal intubation and was associated with an elevated incidence of intractable perioperative bleeding, necessitating delayed sternal closure for hemostasis. The hemopericardium group exhibited higher blood transfusion volumes and rates of re-exploration for bleeding following surgery. However, the 5-year survival (59.5% vs. 75.0%; P = 0.077) and freedom from reoperation rates (93.3% vs. 85.5%; P = 0.416) were comparable between both groups. Multivariable analysis revealed that hemopericardium, cardiopulmonary bypass time, and delayed sternal closure were the risk factors for bleeding re-exploration.

CONCLUSIONS

The presence of hemopericardium in patients with ATAIMH is associated with an elevated incidence of cardiac tamponade and unstable preoperative hemodynamics, which could lead to perioperative bleeding tendencies and high complication rates. However, patients of ATAIMH complicated with hemopericardium undergoing aggressive surgical intervention exhibited long-term surgical outcomes comparable to those without hemopericardium.

Acute type A intramural hematoma: The less-deadly acute aortic syndrome?

OBJECTIVE

To evaluate the short- and midterm outcomes of surgically managed acute type A intramural hematoma (IMH) versus classic acute type A aortic dissection (ATAAD).

METHODS

From 1996 to February 2023, a total of 106 patients with acute type A IMH and 795 patients with classic ATAAD presented for open aortic repair at our institution. Data were obtained from the local Society of Thoracic Surgeons' Data Warehouse and medical chart review.

RESULTS

Compared with the classic ATAAD group, the IMH group was older (65 vs 59 years, P < .001) and more likely to be female (45% vs 32%, P = .005), with fewer comorbidities such as severe aortic insufficiency (5.0% vs 25%, P < .001), acute stroke (2.8% vs 8.3%, P = .05), acute renal failure (5.7% vs 13%, P = .04), and malperfusion syndrome (8.5% vs 26%, P < .001) but more cardiac tamponade (18% vs 11%, P = .03). The IMH group had less aortic root replacement (15% vs 33%, P < .001), zone 2 arch replacements (9.4% vs 18%, P = .02), and shorter crossclamp times (120 minutes vs 150 minutes, P < .001). The operative mortality was significantly lower in the IMH group (0.9% vs 8.8%, P = .005) and a multivariable regression model showed IMH to be protective, odds ratio of 0.11, P = .03. The 10-year survival was similar between the 2 groups (65% vs 61%, P = .35). The hazard ratio of IMH for midterm mortality after surgery was 0.73, P = .12.

CONCLUSIONS

Acute type A IMH could be treated with emergency open aortic repair with excellent short- and midterm outcomes.

Histopathological Gap in Aortic Diseases: A Prospective Analysis

Aortic dissection (AD) is a critical cardiovascular condition with the potential for devastating consequences. This study evaluated the histological changes in the aorta wall in patients with AD and aortic aneurysm (AA) who received surgical aortic replacement. Histopathological data showed that modifications of the media layer (p = 0.0197), myxomatous aspect (p = 0.0001), and subendothelial layer degeneration (p = 0.0107) were more frequently seen in AA versus AD samples. Patients with AA were approximately twice as likely to develop histological changes than those with AD (p = 0.0037). Patients with moderate or severe medial degeneration had a higher chance of developing AD (p = 0.0001). Because the histopathological score proved to be a predictor of both in-hospital and overall mortality, its evaluation should become the standard of care in any patients who undergo aortic replacement. Individualized postoperative management might be influenced by the histopathological aspect of the aortic layer.

Clinical and imaging differences between Stanford Type B intramural hematoma-like lesions and classic aortic dissection

BACKGROUND

Intramural hematoma (IMH) and Aortic dissection (AD) have overlapping features. The aim of this study was to explore the differences between them by comparing the clinical manifestations and imaging features of patients with acute Stanford type B IMH-like lesions and acute Stanford type B AD (ATBAD).

METHODS

This study retrospectively analysed the clinical and computed tomography angiography (CTA) imaging data of 42 IMH-like lesions patients with ulcer-like projection (ULP) and 38 ATBAD patients, and compared their clinical and imaging features.

RESULTS

(1) The IMH-like lesions patients were older than the ATBAD patients (64.2 ± 11.5 vs. 50.9 ± 12.2 years, P < 0.001). The D-dimer level in the IMH-like lesions group was significantly higher than that in the ATBAD group (11.2 ± 3.6 vs. 9.2 ± 4.5 mg/L, P < 0.05). The incidence rate of back pain was significantly higher in the ATBAD group than in the IMH-like lesions group (71.1% vs. 26.2%, P < 0.05). (2) The ULPs of IMH-like lesions and the intimal tears of ATBAD were concentrated in zone 4 of the descending thoracic aorta. The ULPs of IMH-like lesions and the intimal tears of ATBAD were mainly in the upper quadrant outside the lumen (64.3% vs. 65.8%, P > 0.05). (3) The maximum diameter of the ULPs in IMH-like lesions was smaller than that of the intimal tears in ATBAD (7.4 ± 3.4 vs. 10.8 ± 6.8 mm, P = 0.005). The lumen compression ratio in the ULPs plane and the maximum compression ratio of the aortic lumen in the IMH-like lesions group were smaller than that in the ADBAD group (P < 0.05). Fewer aortic segments were involved in IMH-like lesions patients than in ATBAD patients (5.6 ± 2.2 vs. 7.1 ± 1.9 segments, P < 0.005). The IMH-like lesions group had less branch involvement than that of the ATBAD group (P < 0.001).

CONCLUSION

The degree of intimal tears, lumen compression ratio, extent of lesion involvement, and impact on branch arteries in ATBAD are more severe than that of IMH-like lesions. But for the ULPs of IMH-like lesions and intimal tears of ATBAD, they have astonishing similarities in the location of the partition and the lumen quadrant, we have reason to believe that intimal tear is the initial factor in the pathogenesis of this kind of disease, and their clinical and imaging manifestations overlap, but the severity is different. Concerning similarities between these two conditions, these two may be a spectrum of one disease.

Safety and efficacy of thoracic endovascular aortic repair for acute Stanford type B aortic dissection with retrograde type A intramural hematoma

OBJECTIVE

The aim of this study was to evaluate safety and efficacy of thoracic endovascular aortic repair (TEVAR) for acute Stanford type B aortic dissection (TBAD) with retrograde type A intramural hematoma (TAIMH).

METHODS

Patients with acute TBAD with retrograde TAIMH treated with TEVAR between January 1, 2014, to March 31, 2022, were retrospectively reviewed. Aortic diameter and distance were measured using the 3D Slicer image computing platform. Patients' characteristics, procedural, in-hospital and follow-up data, and aortic remodeling were analyzed.

RESULTS

Fifty-two patients (average age, 52.6 years; 42 males [80.8%]) were included. The median interval from symptom onset to TEVAR was 11 days (interquartile range, 7.0-16.8 days). The maximal diameter of the ascending aorta (AA) was <50 mm, and the hematoma thickness in the AA was ≤10 mm in all patients. Both the in-hospital and 30-day mortality rates were 0%. The 30-day complication rate was 11.5%. The overall cumulative survival rates were 100% at 1 year, 97.1% at 3 years, and 92.6% at 5 years. Four of 52 patients (7.7%) developed retrograde type A aortic dissection at 10 days to 4 months postoperatively, and one of 52 patients (1.9%) developed an isolated AA dissection 4 months postoperatively; these five patients were treated and alive at late follow-up in March 2022. The rates of cumulative freedom from thoracic aortic re-intervention were 93.7% at 1 year and 90.7% at 5 years. Positive AA remodeling was observed in 92.3% (48/52) of patients during follow-up. The maximal diameter of AA (mean ± standard error of mean) at admission was 42.7 ± 0.8 mm, which decreased to 39.5 ± 0.9 mm at last follow-up. The maximal AA hematoma thickness at admission was 7.6 ± 0.3 mm, which reduced to 2.2 ± 0.9 mm at last follow-up.

CONCLUSIONS

For selected patients of acute Stanford TBAD with retrograde TAIMH, endovascular repair may be a safe, effective, and durable alternative treatment, if the maximum diameter of the AA is <50 mm and the intramural hematoma thickness in the AA is ≤10 mm.

A radiomics model based on aortic computed tomography angiography: the impact on predicting the prognosis of patients with aortic intramural hematoma (IMH)

Background

The prognosis of aortic intramural hematoma (IMH) is unpredictable, but computed tomography angiography (CTA) plays an important role of high diagnostic performance in the initial diagnosis and during follow-up of patients. In this study, we investigated the value of a radiomics model based on aortic CTA for predicting the prognosis of patients with medically treated IMH.

Method

A total of 120 patients with IMH were enrolled in this study. The follow-up duration ranged from 32 to 1,346 days (median 232 days). Progression of these patients was classified as follows: destabilization, which refers to deterioration in the aortic condition, including significant increases in the thickness of the IMH, the progression of IMH to a penetrating aortic ulcer (PAU), aortic dissection (AD), or rupture; or stabilization, which refers to an unchanged appearance or a decrease in the size or disappearance of the IMH. The patients were divided into a training cohort (n=84) and a validation cohort (n=36). Six different machine learning classifiers were applied: random forest (RF), K-nearest neighbor (KNN), Gaussian Naive Bayes, decision tree, logistic regression, and support vector machine (SVM). The clinical-radiomics combined nomogram model was established by multivariate logistic regression. The area under the receiver operating characteristic (ROC) curve (AUC) was implemented to evaluate the discrimination performance of the models. The calibration curves and Hosmer-Lemeshow test were used for evaluating model calibration. DeLong's test was performed to compare the AUC performance of models.

Results

Among all of the patients, 60 patients showed destabilization and 60 patients remained stable. A total of 12 radiomic features were retained after application of the least absolute shrinkage and selection operator (LASSO). These features were used for the machine learning model construction. The SVM-radial basis function (SVM-RBF) model obtained the best performance with an AUC of 0.765 (95% CI, 0.593-0.906). In the validation cohort, the combined clinical-radiomics model [AUC =0.787; 95% confidence interval (CI), 0.619-0.923] showed a significantly higher performance than did the clinical model (AUC =0.596; 95% CI, 0.413-0.796; P=0.021) and had a similar performance to the radiomics model (AUC =0.765; 95% CI, 0.589-0.906; P=0.672).

Conclusions

A quantitative nomogram based on radiomic features of CTA images can be used to predict disease progression in patients with IMH and may help improve clinical decision-making.

Experimental Study of the Propagation Process of Dissection Using an Aortic Silicone Phantom

BACKGROUND

The mortality of acute aortic dissection (AD) can reach 65~70%. However, it is challenging to follow the progress of AD formation. The purpose of this work was to observe the process of dissection development using a novel tear-embedded silicone phantom.

METHODS

Silicone phantoms were fabricated by embedding a torn area and primary tear feature on the inner layer. CT scanning and laser lightening were conducted to observe the variations in thickness and volume of the true lumen (TL) and false lumen (FL) during development.

RESULTS

The model with a larger interlayer adhesion damage required a lower pressure to trigger the development of dissection. At the initiation stage of dissection, the volume of TL increased by 25.5%, accompanied by a 19.5% enlargement of tear size. The force analysis based on the change of tear size verified the deduction of the process of interlaminar separation from the earlier studies.

CONCLUSIONS

The primary tear and the weakening adhesion of the vessel layers are key factors in AD development, suggesting that some forms of primary damage to the arterial wall, in particular, the lumen morphology of vessels with straight inner lumen, should be considered as early risk predictors of AD.

Ascending aortic intramural hematoma: current concepts

PURPOSE OF REVIEW

Type A intramural hematoma (TAIMH) is an acute aortic disease characterized by the presence of hematoma in the aortic media and involving the ascending aorta. Open repair seems to be the first treatment approach, although recent evidence highlights that the best management of TAIMH is controversial. This review will focus on the current concept for TAIMH management and factors affecting the decision making.

RECENT FINDINGS

Recent studies have evaluated the role of open and endovascular repair, as well as conservative management in patients with TAIMH. More specific imaging findings seem to affect decision making for urgent repair.

SUMMARY

Despite TAIMH's acute nature, conservative management seems to represent a valid option for urgent approach, presenting similar mortality to open and endovascular repair. Comparative data are limited, however, in experienced centers, any approach may be applied with encouraging results. Endovascular management, which is mainly applied to manage retrograde TAIMH, is related to lower mortality and morbidity compared to open repair in this group of patients while aortic remodeling seems beneficial with this approach. Imaging findings, as ulcer-like lesions, hematoma thickness, concomitant dissection and aortic diameter, related to higher complication rate, set the indication for interventional management. Further research, including prospective data and registries, and ideally, randomized data may further clarify the best approach and factors indicating urgent repair.

Thoracic Endovascular Aortic Repair for Retrograde Type A Aortic Intramural Hematoma

Objectives: To evaluate the effects of thoracic endovascular aortic repair (TEVAR) in descending aorta for retrograde type A aortic intramural hematoma (re-TAIMH).

Methods: From January 2013 to September 2019, 65 consecutive patients diagnosed with re-TAIMH and treated by TEVAR were enrolled in this retrospective cohort study, of whom 44 patients presented with entry tear in descending aorta (Group A) and 21 with penetrating atherosclerotic ulcer (Group B). The clinical data, including baseline characteristics, adverse events, aortic remolding, and overall survival were reviewed.

Results: The mean age of all the patients was 52.0 ± 8.3 years, and 54 (83.1%) patients were men. The mean maximal ascending aortic diameter (MAAD) was 43.1 ± 5.4 mm, and the mean maximal ascending aortic hematoma thickness (MAAHT) was 9.6 ± 4.7 mm. TEVAR was performed under general anesthesia in 53 (81.5%) patients, while 12 (18.5%) patients were treated under local anesthesia. There were two deaths during hospitalization (one with rupture and another with multiple organ dysfunction syndrome), and overall survival at 1, 4, and 7 years for all 65 patients was 93.8, 92.0, and 87.4%, respectively. The MAAD and MAATH decreased significantly after TEVAR (p < 0.05) in the two groups, so did the mean descending aortic diameter at the pulmonary bifurcation level. Type I endoleak, dialysis, progression to type A aortic dissection, and enlargement in MAAHT and MAAD were more common complications, which occurred in four, three, two, and two patients, respectively.

Conclusion: Patients with retrograde TAIMH treated by TEVAR had a favorable prognosis including late survival and aortic remolding. However, some post-intervention complications were not negligible.

Computed Tomography Angiography Assessment of Acute Aortic Syndromes: Classification, Differentiating Imaging Features, and Imaging Interpretation Pitfalls

An acute aortic syndrome (AAS) is an important life-threatening condition that requires early detection and management. Acute intramural hematoma (IMH), aortic dissection (AD) and penetrating atherosclerotic ulcer (PAU) are included in AAS. ADs can be classified using the well-known Stanford or DeBakey classification systems. However, these classification systems omit description of arch dissections, anatomic variants, and morphologic features that impact outcome. The Society for Vascular Surgery and Society of Thoracic Surgeons (SVS-STS) have recently introduced a classification system that classifies ADs according to the location of the entry tear (primary intimomedial tear, PIT) and the proximal and distal extent of involvement, but does not include description of all morphologic features that may have diagnostic and prognostic significance. This review describes these classification systems for ADs and other AAS entities as well as their limitations. Typical computed tomography angiography (CTA) imaging appearance and differentiating features of ADs, limited intimal tears (LITs), IMHs, intramural blood pools (IBPs), ulcer-like projections (ULPs), and PAUs will be discussed. Furthermore, this review highlights common imaging interpretation pitfalls, what should be included in a comprehensive CTA report, and provides a brief overview of current management options.