Intimal Tear Research Articles

Central vs peripheral vascular factors determining risk of aortic dissection

Hypertension is the commonest cause of “central” aortic dissection, despite being an “peripheral” arteriole disease. We hypothesised that known regional variations in peripheral organ perfusion, due to variation in arteriole tone, via its effect on differential head and neck vessel flows can alter the risk and location of central aortic dissection. This might help to explain why some hypertensive patients dissect their aorta and others don't despite having similar aortic geometry. We utilised a simple 2D computational fluid dynamic model to test our hypothesis. We hypothesise (1) that variations in “peripheral” organ flow can alter the site of “central” aortic dissection, despite the blood pressure and cardiac output being identical, (2) variations in cardiac output at rest may also help to explain the risk of dissection but not the site of the initial intimal tear, and (3) atrial fibrillation, a known factor for aortic dissection, increases the risk via stroke volume variation. MRI scanning, via regional aortic branch flow quantification, may help to identify individuals who have a family history of dissection/aneurysm, who are normotensive with normal aortic anatomy that have a high potential risk for dissection due to calculated high wall velocity/shear stresses. This may allow selective beta blocker prescriptions in an asymptomatic patient population that is at a predicted high risk of aortic dissection – a hither to unidentified patient subpopulation.

Intravascular laser lithotripsy for calcium fracture in human coronary arteries.

Electrical intravascular lithotripsy (E-IVL) uses shock waves to fracture calcified plaque. We aimed to demonstrate the ability of laser IVL (L-IVL) to fracture calcified plaques in ex vivo human coronary arteries and to identify and evaluate the mechanisms for increased vessel compliance. Shock waves were generated by a Ho:YAG (Holmium: yttrium-aluminium-garnet) laser (2 J, 5 Hz) and recorded by a high-speed camera and pressure sensor. Tests were conducted on phantoms and 19 fresh human coronary arteries. Before and after L-IVL, arterial compliance and optical coherence tomography (OCT) pullbacks were recorded, followed by histology. Additionally, microcomputed tomography (micro-CT) and scanning electron microscopy (SEM) were performed. Finite element models (FEM) were utilised to examine the mechanism of L-IVL. Phantom cracks were obtained using 230 μm and 400 μm fibres with shock-wave pressures of 84±5.0 atm and 62±0.4 atm, respectively. Post-lithotripsy, calcium plaque modifications, including fractures and debonding, were identified by OCT in 78% of the ex vivo calcified arteries (n=19). Histological analysis revealed calcium microfractures (38.7±10.4 μm width) in 57% of the arteries which were not visible by OCT. Calcium microfractures were verified by micro-CT and SEM. The lumen area increased from 2.9±0.4 to 4.3±0.8 mm2 (p<0.01). Arterial compliance increased by 2.3±0.6 atm/ml (p<0.05). FEM simulations suggest that debonding and intimal tears are additional mechanisms for increased arterial compliance. L-IVL has the capability to increase calcified coronary artery compliance by multiple mechanisms.

Oxidative stress drives vascular smooth muscle cell damage in acute Stanford type A aortic dissection through HIF-1α/HO-1 mediated ferroptosis

BackgroundAcute Stanford type A aortic dissection (ATAAD) is characterized by intimal tearing and false lumen formation containing large amounts of erythrocytes with heme. Heme oxygenase 1 (HO-1) is the key enzyme to degrade heme for iron accumulation and further ferroptosis. The current study aimed at investigating the role of HO-1 in the dissection progression of ATAAD. MethodsBioinformatic analyses and experimental validation were performed to reveal ferroptosis and HO-1 expression in ATAAD. Human aortic vascular smooth muscle cell (HA-VSMC) was used to explore underlying molecular mechanisms and the role of HO-1 overexpression in ATAAD. ResultsFerroptosis was identified as a critical manner of regulated cell death in ATAAD. HO-1 was screened as a key signature of ferroptosis in ATAAD, which was closely associated with oxidative stress. Single cell/nucleus transcriptomic analysis and histological staining revealed that HO-1 and HIF-1α were upregulated in vascular smooth muscle cell (VSMC) of ATAAD. Further in vitro experiments showed that H2O2-induced oxidative stress increased VSMC ferroptosis with the overexpression of HO-1, which could be suppressed by HIF-1α inhibitor PX-478. HIF-1α could transcriptionally regulate the expression of HO-1 through binding to its promoter region. Pharmacological inhibition of HO-1 by zinc protoporphyrin (ZnPP) did not reduce H2O2-induced HA-VSMC damage without heme co-incubation. However, H2O2-induced HA-VSMC damage was worsened when heme was added into the medium, and ZnPP could reduce HA-VSMC damage in this condition. ConclusionHO-1 is a key signature of VSMC ferroptosis in ATAAD. HIF-1α/HO-1 mediated ferroptosis might participate in oxidative stress induced VSMC damage.

Relationship between false lumen morphology and entry tear in acute type A aortic dissection.

This study aimed to investigate the relationship between false lumen morphology and the size, aortic segment and position of the entry tear for acute type A aortic dissection. The records of patients who underwent emergency operation for acute type A aortic dissection in our institution between April 2011 and May 2022 were examined. Data regarding size, location and position of the entry tear and preoperative computed tomography findings were reviewed. The relationship of these variables with false lumen morphology was examined and retrospectively compared according to tear size. Of 243 cases, characteristics of the entry tear, visualized during surgery, were confirmed in 134 cases (age = 70.9 ± 12.6 years, male = 45.5%). Tear sizes at different aortic segments were not significantly different (P = 0.376). Tears posterior to the lesser curvature were significantly smaller than those anterior to the greater curvature (P = 0.004). A thrombosed false lumen was associated with a significantly smaller tear size and position on the posterior to the lesser curvature side in aortic cross-section (all P < 0.001). Multivariate analysis showed that tear size, the presence of re-entry and tear position anterior to the greater curvature were independent predictors of a patent false lumen. In acute type A aortic dissection, larger tear size, the presence of re-entry and tear position anterior to the greater curvature are risk factors for a patent false lumen. Although the results of this study are valid only for patients in whom intimal tears were detected during aortic surgery, this trend may provide information for pathophysiology of the disease.

A Novel Endovascular Double-Disc Implant for Sealing Intimal Tears in Aortic Dissection

Postdissection thoracoabdominal aortic aneurysm incidence after thoracic endovascular aortic repair for type B aortic dissection is high, with residual distal tears being a major reason for persistent blood flow in the false lumen. The EndoPatch is an endovascular double-disc implant for sealing re-entry tears in aortic dissection, isolating blood flow in the false lumen and promoting thrombosis formation. Compared with conventional endovascular treatment techniques, this endovascular double-disc implant’s small size and minimal working space requirements may reduce the risk of spinal ischemia and offer flexible vascular access. Although several barriers still impede this endovascular device’s broad application, its innovative design, flexible vascular access, and streamlined surgical process make it a promising alternative for managing intimal tears in aortic dissection, either alone or as a supplementary method combined with conventional endovascular techniques. (Guo’s Entry Tear Repair: The First in Man Study of Endopatch System; NCT04745039)

Variability of time to healing of Spontaneous Coronary Artery Dissection assessed through coronary CT angiography

Abstract Background Spontaneous coronary artery dissection (SCAD) results from a spontaneous, non-traumatic, and non-iatrogenic separation of the coronary arterial wall by intramural hematoma caused by intimal tear or spontaneous hemorrhage that is unrelated to atherosclerosis. SCAD is an important cause of myocardial infarction particularly in young to middle-aged women. Natural history of this condition is poorly understood: spontaneous healing has been demonstrated through coronary angiography in the vast majority of patients at long term follow up, but the timing of healing is still not clear. Nowadays, Coronary CT angiography (CCTA) is emerging as a noninvasive option to evaluate SCAD healing at least for coronary arteries with diameter ≥2mm and could help in understanding the natural history of this condition. Methods In this single-centre, retrospective study, patients affected by SCAD between 2017 and 2022 were included. Patients with SCAD involving coronary arteries with diameter ≥2mm who did not undergo percutaneous coronary intervention (PCI) and underwent to at least one CCTA during follow up were evaluated with regard to evolution of SCAD and time to healing. Results Among 93 patients for whom diagnosis of SCAD was posed by coronary angiography, 33 conservatively managed patients (84.8% female, mean age 51.8±12.3 years) underwent to at least one CCTA during follow up. At a median time of 49 days (IQR 13 to 82 days), a complete healing of SCAD was demonstrated in 6 patients (18.2%), while most of the patients showed a stability or partial healing and 1 patient (3.0%) an extension of SCAD. During further follow up, of 10 patients who did not show a significant healing at the first CCTA, 4 patients showed a complete healing, while 6 patients showed a stability of SCAD extension or only partial healing at the longest available CCTA follow up (median follow up 191 days, IQR 96 to 249 days). As regards clinical events, no death, myocardial infarctions, or target vessel PCIs were reported during follow up. Conclusion Spontaneous healing is commonly seen in SCAD and can be demonstrated by CCTA. However, the timing of complete healing is largely variable between individuals: therefore, studies focusing factors impacting natural history of SCAD are needed.

Acute Aortic Dissection Type A in Younger Patients (< 60 Years Old) - Does Full Arch Replacement Provide Benefits Compared to Limited Approach?

Acute aortic dissection Stanford type A (AADA) is a surgical emergency associated with high morbidity and mortality. Although surgical management has improved, the optimal therapy is a matter of debate. Different surgical strategies have been proposed for patients under 60 years old. This paper evaluates the postoperative outcome and the need for secondary aortic operation after a limited surgical approach (proximal arch replacement) vs. extended arch repair. Between January 2000 and January 2018, 530 patients received surgical treatment for AADA at our hospital; 182 were under 60 years old and were enrolled in this study - Group A (n=68), limited arch repair (proximal arch replacement), and group B (n=114), extended arch repair (> proximal arch replacement). More pericardial tamponade (P=0.005) and preoperative mechanical resuscitation (P=0.014) were seen in Group A. More need for renal replacement therapy (P=0.047) was seen in the full arch group. Mechanical ventilation time (P=0.022) and intensive care unit stay (P<0.001) were shorter in the limited repair group. Thirty-day mortality was comparable (P=0.117). New onset of postoperative stroke was comparable (Group A four patients [5.9%] vs. Group B 15 patients [13.2%]; P=0.120). Long-term follow-up did not differ significantly for secondary aortic surgery. Even though young patients received only limited arch repair, the outcome was comparable. Full-arch replacement was not beneficial in the long-time follow-up. A limited approach is justified in the cohort of young AADA patients. Exemptions, like known Marfan syndrome and the presence of an intimal tear in the arch, should be considered.

Acute-on-Chronic Aortic Dissection: Management and Outcomes of the Unstable “Triple-Lumen” Aorta

BackgroundThe impact of acute aortic dissection of the chronically dissected distal aorta is unknown. This study sought to describe the incidence and characteristics of the triple-lumen aortic dissection and its impact on survival. MethodsFrom 2010 to 2021, a query of a single-institution aortic database identified 1149 patients with chronic distal aortic dissection. Thirty-three (2.9%) patients with at least 3 distinct lumens and 2 separate “primary” intimal tears were identified by analysis of contrast-enhanced cross-sectional imaging. Triple-lumen patients were exactly matched with a cohort of double-lumen patients on a 1:1 ratio using 5 preoperative variables, and outcomes between the groups were assessed. ResultsThe median age at time of initial dissection in patients with a triple-lumen dissection was 46 years. Initial dissection was a type A in 33% and a type B in 67% of patients. The median time from initial dissection to triple-lumen diagnosis was 4.2 years. On diagnosis of the triple-lumen aorta, 85% of patients required urgent aortic repair for rapid growth (36%), aortic diameter ≥55 mm (30%), malperfusion (6%), intractable pain (6%), and rupture/type A (6%). Thirty-day mortality after triple lumen dissection was 12%. ConclusionsAcute-on-chronic distal dissection resulting in a triple-lumen aorta should be classified as a “complicated” type B dissection as these patients typically have large aneurysms and a high incidence of rapid false lumen expansion requiring urgent surgical repair.

Clinical Outcomes and Factors Associated With Aortic Shrinkage After Thoracic Endovascular Aortic Repair for Aneurysmal Chronic Aortic Dissection.

The effectiveness of thoracic endovascular aortic repair (TEVAR) for chronic aortic dissection (AD) with aneurysmal degeneration remains controversial. We retrospectively investigated clinical outcomes and assessed predictors of aortic shrinkage after TEVAR for chronic aneurysmal AD. Between January 2010 and December 2021, 70 patients with double-barrel-type chronic AD were enrolled. Major intimal tears in thoracic aorta were covered by stent graft. Early and late clinical outcomes, and diameter change of downstream aorta during follow-up period were reviewed. Subsequently, factors associated with aortic shrinkage were assessed by logistic regression analysis. Mean age was 63 (interquartile range [IQR]: 54-68) years, 54 (80%) men, median duration from AD onset was 4 (IQR: 1-10) years, and maximum aortic diameter was 53 (IQR: 49-58) mm. Supra-aortic debranching procedure was required in 57 (81%) patients. Early aorta-related death occurred in 2 (3%) patients. Both stroke and spinal cord ischemia occurred in 1 (2%) patient. Five-year freedom rates from aorta-related death and reintervention were 96% and 51%, respectively. Sixty-four patients underwent follow-up computed tomography (84%) 1 year after TEVAR, with 33 (52%) achieving aortic shrinkage. In multivariable analysis, duration from AD onset (per year) (odds ratio [OR]: 0.82, 0.70-0.97; p=0.017) and maximum aortic-diameter ratio between aortic arch and descending aorta (per 0.1) (morphologic index; OR: 1.34, 1.04-1.74; p=0.023) were independent aortic shrinkage predictors. Thoracic endovascular aortic repair for chronic AD with aneurysmal degeneration achieved satisfactory survival outcomes, but with a considerable reintervention rate. Duration from AD onset and preoperative aortic morphology could affect post-TEVAR aortic shrinkage. Earlier intervention could lead to better aortic shrinkage. Thoracic endovascular aortic repair for chronic aortic dissection with aneurysmal degeneration showed low incidence of early and late aorta-related death. By contrast, aortic shrinkage rate was low with high incidence of reintervention to the residual downstream aorta. According to the assessment of preoperative variables, chronicity and aortic morphology could predict postoperative aortic shrinkage.

Tomo-seq identifies NINJ1 as a potential target for anti-inflammatory strategy in thoracic aortic dissection

BackgroundThoracic aortic dissection (TAD) is a life-threatening disease caused by an intimal tear in the aorta. The histological characteristics differ significantly between the tear area (TA) and the distant area. Previous studies have emphasized that certain specific genes tend to cluster at the TA. Obtaining a thorough understanding of the precise molecular signatures near the TA will assist in discovering therapeutic strategies for TAD.MethodsWe performed a paired comparison of the pathological patterns in the TA with that in the remote area (RA). We used Tomo-seq, genome-wide transcriptional profiling with spatial resolution, to obtain gene expression signatures spanning from the TA to the RA. Samples from multiple sporadic TAD patients and animal models were used to validate our findings.ResultsPathological examination revealed that the TA of TAD exhibited more pronounced intimal hyperplasia, media degeneration, and inflammatory infiltration compared to the RA. The TA also had more apoptotic cells and CD31+α-SMA+ cells. Tomo-seq revealed four distinct gene expression patterns from the TA to the RA, which were inflammation, collagen catabolism, extracellular matrix remodeling, and cell stress, respectively. The spatial distribution of genes allowed us to identify genes that were potentially relevant with TAD. NINJ1 encoded the protein-mediated cytoplasmic membrane rupture, regulated tissue remodeling, showed high expression levels in the tear area, and co-expressed within the inflammatory pattern. The use of short hairpin RNA to reduce NINJ1 expression in the beta-aminopropionitrile-induced TAD model led to a significant decrease in TAD formation. Additionally, it resulted in reduced infiltration of inflammatory cells and a decrease in the number of CD31+α-SMA+ cells. The NINJ1-neutralizing antibody also demonstrated comparable therapeutic effects and can effectively impede the formation of TAD.ConclusionsOur study showed that Tomo-seq had the advantage of obtaining spatial expression information of TAD across the TA and the RA. We pointed out that NINJ1 may be involved in inflammation and tissue remodeling, which played an important role in the formation of TAD. NINJ1 may serve as a potential therapeutic target for TAD.

Preoperative diagnostic value of coronary CT angiography in acute Stanford type A aortic dissection involving the coronary arteries

To assess the diagnostic value of coronary computed tomography angiography (CCTA) in acute type A aortic dissection (ATAAD) with coronary artery involvement and to evaluate whether CCTA could provide potentially useful information for selecting the surgical method. Patients with ATAAD treated from January 2019 to December 2020 were reviewed retrospectively. Involvement of the coronary arteries based on CCTA findings were grouped into three major types and five subtypes. Interobserver and intraobserver diagnostic agreement for five subtypes were determined. The patients were divided into the coronary artery bypass grafting (CABG) and non-CABG groups, and the proportions of the five subtypes between the two groups were compared. A total of 95 patients were enrolled in this study. Interobserver and intraobserver diagnostic agreement were both substantial in the left and right coronary arteries. Overall, the proportions of the five subtypes of coronary artery involvement were significantly different between the two groups (p<0.001). The proportion of Type A was elevated in the non-CABG group compared with the CABG group (22.6% versus 71.9%); by contrast, the proportions of Type B1 (35.5% versus 14.1%), Type B2 (19.4% versus 10.9%), Type C1 (6.5% versus 0%), and Type C2 (16.1% versus 3.1%) were elevated in the CABG group. CCTA is reliable in evaluating coronary artery involvement by ATAAD. The present retrospective study indicated that CABG may be considered if the intimal flap disrupts the coronary orifice and causes luminal stenosis >50%, particularly Type B, or if an intimal tear occurs in the coronary orifice (Type C), which deserve further validation through prospective studies.

A Comparison of Retrospective ECG-Gated CT and Surgical or Angiographical Findings in Acute Aortic Syndrome.

The best cardiac phases in retrospective ECG-gated CT for detecting an intimal tear (IT) in aortic dissection (AD) and an ulcer-like projection (ULP) in an intramural hematoma (IMH) have not been established. This study aimed to compare the detection accuracy of diastolic-phase and systolic-phase ECG-gated CT for IT in AD and ULP in IMH, with subsequent surgical or angiographical confirmation as the reference standard.In total, 81 patients (67.6 ± 11.8 years; 41 men) who underwent emergency ECG-gated CT and subsequent open surgery or thoracic endovascular aortic repair for AD (n = 52) or IMH (n = 29) were included. The accuracies of detecting IT and ULP were compared among only diastolic-phase, only systolic-phase, and both diastolic-phase and systolic-phase methods of retrospective ECG-gated CT; surgical or angiographical findings were used as the reference standard. The detection accuracy for IT and ULP using only diastolic-phase, only systolic-phase, and both diastolic-phase and systolic-phase methods of ECG-gated CT was 93% [95% CI: 87-97], 94% [95% CI: 88-97], and 95% [95% CI: 90-97], respectively. There were no significant differences in detection accuracy among the 3 acquisition methods (P = 0.55). Similarly, there were no significant differences in the accuracy of detecting IT in AD (P = 0.55) and ULP in IMH (P > 0.99) among only diastolic-phase, only systolic-phase, and both diastolic- and systolic-phase ECG-gated CT.Retrospective ECG-gated CT for detecting IT in AD and ULP in IMH yields highly accurate findings. There were no significant differences seen among only diastolic-phase, only systolic-phase, and both diastolic-phase and systolic-phase ECG-gated CT.

Neurovascular injury from supracondylar fractures in children: a 10-year experience of 762 cases.

We evaluated the management of supracondylar paediatric fractures at our institution over a 10-year period in this retrospective cohort study. In total, 762 children with a supracondylar fracture were treated. The mean age of injury was 5.2 years. The incidence of documented nerve and/or vascular injury was 8.3%. A total of 26 patients had early plastic surgeon involvement; of these, 25 had an open exploration. Eight patients required vein grafting for brachial artery reconstruction for intimal tears. There was one nerve rupture requiring repair and 12 children underwent neurolysis. There were 17 late referrals to the plastic surgery service, of which three were explored (two neurolysis, one neuroma resection and sural nerve grafting). In all cases of nerve injury, the deficit took 7.9 months to recover, indicating a more significant injury than neurapraxia. Early exploration of supracondylar fractures allows direct visualization of the extent of neurovascular injury and immediate intervention.Level of evidence: IV.

The Use of Cutting Balloons in Published Cases of Acute Coronary Syndrome Caused by Spontaneous Coronary Artery Dissection.

Spontaneous coronary artery dissection (SCAD) is a non-traumatic, non-atherosclerotic layering of the coronary artery wall due to the presence of a subintimal hematoma or an intimal tear with the creation of a false lumen that compresses the true lumen and restricts or obstructs the flow. Patients with SCAD and preserved coronary flow are treated conservatively according to the general recommendations. However, percutaneous coronary intervention should be considered in patients with artery occlusion and/or refractory ischemia. Stenting is associated with increased risks comprising stenting in the false lumen, in-stent thrombosis, and/or stent malappositon as well as antegrade or retrograde propagation of the intramural hematoma. Intracoronary imaging is of great value both for the diagnosis and treatment of SCAD. There is rising scrutiny on the use of cutting balloons in acute coronary syndrome caused by SCAD. The idea of using cutting balloons is to fenestrate the intima and drain the intramural hematoma. Our review presents an analysis of 17 published cases of cutting balloon (CB) use in SCAD. What is encouraging is that of the 12 published cases, in 11 Thrombolysis in Myocardial Infarction (TIMI) 3 flow was established with this technique, and TIMI 2 flow in one, without subsequent stent implantation. Four patients received a stent after the CB use, while one patient underwent CB angioplasty after hematoma propagation caused by stent implantation. In all cases, patients were asymptomatic at follow-up, with TIMI 3 flow.

Anatomic feasibility of a modular Endo-Bentall stent graft system for type A aortic dissection

ObjectiveThe implementation of thoracic endovascular aortic repair in patients with type A aortic dissection has been strictly constrained due to the pulsatile movement and distensibility and the insufficient length of landing zones on ascending aorta. The most prevalent anatomical limitation is the insufficient length of proximal and distal landing zones. We propose a modularly designed Endo-Bentall stent graft system to broaden the scope of thoracic endovascular aortic repair in the ascending aorta by covering intimal tears in the aortic root and ascending aorta and reconstructing coronary arteries. This study was conducted to assess the anatomical feasibility of a novel stent graft design. MethodsIn this study, we included 152 patients with type A aortic dissection for image measurement and analysis. All computed tomography angiography images were assessed on a 3mensio Workstation version 10.2 (3mensio Medical Imaging B.V.) utilizing the centerline method. We compared the diameters and lengths at various planes in relation to the proposed anatomical criteria for the modular Endo-Bentall stent graft system. ResultsThe patients were predominantly male (67.1%), with a median age of 56.5 years (interquartile range, 50.0-65.0 years). Among all aortic dissections, 91.5% extended proximally to the sinotubular junction, whereas only 8.6% were restricted to the tubular ascending aorta. The median perimeter-derived diameter of the aortic annulus was 24.1 mm. The median maximum aortic diameter at the sinotubular junction and brachiocephalic trunk were 44.6 mm and 43.5 mm, respectively. The median height of the left coronary artery, right coronary artery, and sinus of Valsalva were 12.7 mm, 16.7 mm, and 28.4 mm, respectively. After applying exclusion criteria, 66.4% of all patients were anatomically eligible for the modular Endo-Bentall stent graft system. A total of 85.1% of patients were suitable for stent grafts with lengths of 70 mm, 80 mm, or 90 mm. Both antegradely and retrogradely tapered stent grafts were required, according to the diameter differences between the STJ and brachiocephalic trunk. ConclusionsUtilizing the modular Endo-Bentall stent-graft design, approximately two-thirds of patients with type A aortic dissection are anatomically eligible for endovascular repair. Further animal studies are required to optimize the device design.

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

BackgroundIntramural 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).MethodsThis 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).ConclusionThe 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.

Histological evidence of a connection between true and false lumen in spontaneous coronary artery dissection

The pathophysiological mechanism underlying spontaneous coronary artery dissection remains unclear. Although an endothelial-intimal disruption is assumed to be involved as either a primary or secondary event, the presence of a tear in the coronary intima has not been histologically presented, to our knowledge. We present three autopsy cases of spontaneous coronary artery dissection in which histopathological examination revealed an intimal tear and connection between true and false lumen in the area of the dissection.

Intravascular photoacoustic and optical coherence tomography imaging dual-mode system for detecting spontaneous coronary artery dissection: A feasibility study

In this work, we present an intravascular dual-mode endoscopic system capable of both intravascular photoacoustic imaging (IVPAI) and intravascular optical coherence tomography (IVOCT) for recognizing spontaneous coronary artery dissection (SCAD) phantoms. IVPAI provides high-resolution and high-penetration images of intramural hematoma (IMH) at different depths, so it is especially useful for imaging deep blood clots associated with imaging phantoms. IVOCT can readily visualize the double-lumen morphology of blood vessel walls to identify intimal tears. We also demonstrate the capability of this dual-mode endoscopic system using mimicking phantoms and biological samples of blood clots in ex vivo porcine arteries. The results of the experiments indicate that the combined IVPAI and IVOCT technique has the potential to provide a more accurate SCAD assessment method for clinical applications.

Framework Development for Patient-Specific Compliant Aortic Dissection Phantom Model Fabrication: Magnetic Resonance Imaging Validation and Deep-Learning Segmentation.

Type B aortic dissection is a life-threatening medical emergency that can result in rupture of the aorta. Due to the complexity of patient-specific characteristics, only limited information on flow patterns in dissected aortas has been reported in the literature. Leveraging the medical imaging data for patient-specific in vitro modeling can complement the hemodynamic understanding of aortic dissections. We propose a new approach toward fully automated patient-specific type B aortic dissection model fabrication. Our framework uses a novel deep-learning-based segmentation for negative mold manufacturing. Deep-learning architectures were trained on a dataset of 15 unique computed tomography scans of dissection subjects and were blind-tested on 4 sets of scans, which were targeted for fabrication. Following segmentation, the three-dimensional models were created and printed using polyvinyl alcohol. These models were then coated with latex to create compliant patient-specific phantom models. The magnetic resonance imaging (MRI) structural images demonstrate the ability of the introduced manufacturing technique for creating intimal septum walls and tears based on patient-specific anatomy. The in vitro experiments show the fabricated phantoms generate physiologically-accurate pressure results. The deep-learning models also show high similarity metrics between manual segmentation and autosegmentation where Dice metric is as high as 0.86. The proposed deep-learning-based negative mold manufacturing method facilitates an inexpensive, reproducible, and physiologically-accurate patient-specific phantom model fabrication suitable for aortic dissection flow modeling.

Closing of a Patent Tear Above the Aortic Hiatus and Type A Aortic Dissection Outcomes

BackgroundA strategy combining tear-oriented initial surgical procedure and subsequent thoracic endovascular aortic repair (TEVAR) can be adopted for acute type A aortic dissection (ATAAD). This study investigated this strategy’s outcomes and the role of the aortic hiatus (AH). MethodsOverall, 192 consecutive patients with ATAAD who underwent initial surgery between 2012 and 2021 were assessed in this observational retrospective study. The reintervention rate, the relationship of the residual tear location above or below the AH, and the outcomes of subsequent TEVAR and redo distal open repair were assessed. ResultsThe initial surgery’s in-hospital death rate was 8.3%; the subsequent TEVAR and redo distal open repair rates were 28% and 3%, respectively. Reintervention was performed in 93% and 0% of patients with tears above and below the AH, respectively, with a 0% mortality rate. ConclusionsIn false lumen expansion cases, timely detection and closure of the residual intimal tear above the AH with subsequent TEVAR might improve ATAAD outcomes.