Endovascular management of acute aortic dissection

Surgical choice for the treatment of partial intestinal ischemic necrosis caused by acute type a aortic dissection combined with malperfusion of superior mesenteric artery

Acute type A aortic dissection is a severe cardiovascular disease characterized by rapid onset and high mortality. Traditionally, urgent open aortic repair is performed after admission to prevent aortic rupture and death. However, when combined with malperfusion syndrome, the low perfusion of the superior mesenteric artery can further lead to intestinal necrosis, significantly impacting the surgery's prognosis and potentially resulting in adverse consequences, bringing. This presents great significant challenges in treatment. Based on recent domestic and international research literature, this paper reviews the mechanism, current treatment approaches, and selection of surgical methods for poor organ perfusion caused by acute type A aortic dissection. The literature review findings suggest that central aortic repair can be employed for the treatment of acute type A aortic dissection with inadequate perfusion of the superior mesenteric artery. The superior mesenteric artery can be windowed and (/or) stented, followed by delayed aortic repair. Priority should be given to revascularization of the superior mesenteric artery, followed by central aortic repair. During central aortic repair, direct blood perfusion should be performed on the distal true lumen of the superior mesenteric artery, leading to resulting in favorable therapeutic outcomes. The research results indicate that even after surgical aortic repair, intestinal ischemic necrosis may still occur. In such cases, prompt laparotomy and necessary necrotic bowel resection are crucial for saving the patient's life.

A systematic review and meta-analysis of retrograde type A aortic dissection after thoracic endovascular aortic repair in patients with type B aortic dissection

BACKGROUND

Retrograde type A dissection (RTAD) is a devastating complication of thoracic endovascular repair (TEVAR) with low incidence but high mortality. The objective of this study is to report the incidence, mortality, potential risk factors, clinical manifestation and diagnostic modalities, and medical and surgical treatments.

METHODS

A systematic review and single-arm and two-arm meta-analyses evaluated all published reports of RTAD post-TEVAR through January 2021. All study types were included, except study protocols and animal studies, without time restrictions. Outcomes of interest were procedural data (implanted stent-grafts type, and proximal stent-graft oversizing), the incidence of RTAD, associated mortality rate, clinical manifestations, diagnostic workouts and therapeutic management.

RESULTS

RTAD occurred in 285 out of 10,600 patients: an estimated RTAD incidence of 2.3% (95% CI: 1.9-2.8); incidence of early RTAD was approximately 1.8 times higher than late. Wilcoxon signed-rank testing showed that the proportion of RTAD patients with acute type B aortic dissection (TBAD) was significantly higher than those with chronic TBAD (P = .008). Pooled meta-analysis showed that the incidence of RTAD with proximal bare stent TEVAR was 2.1-fold higher than with non-bare stents: risk ratio was 1.55 (95% CI: 0.87-2.75; P = .13). Single arm meta-analysis estimated a mortality rate of 42.2% (95% CI: 32.5-51.8), with an I2 heterogeneity of 70.11% (P < .001).

CONCLUSION

RTAD is rare after TEVAR but with high mortality, especially in the first month post-TEVAR with acute TBAD patients at greater risk as well as those treated with proximal bare stent endografts.

Intravascular US: Applications in Interventional Radiology

Interventional radiology applications of intravascular US (IVUS) continue to expand, complementing intraprocedural angiography and providing a unique vantage from which to guide endovascular interventions. Vascular pathologic conditions become sonographically visualized rather than inferred from the planar appearance of the opacified vascular lumen. Perivascular targets become sonographically visualized rather than approximated on the basis of fluoroscopic landmarks. The authors introduce broad categories of IVUS catheters, namely radial and side-firing varieties, as well as prevailing options for each and their technical specifications. Common applications within interventional radiology are covered in a systems approach, including deep venous thrombosis, May-Thurner syndrome, nutcracker syndrome, transjugular intrahepatic portosystemic shunts, aortic interventions, peripheral arterial disease, and endovascular or perivascular biopsy. Discussions are accompanied by technical pearls from the authors, and summarized evidence where IVUS has been shown to reduce procedural time, intravascular contrast agent dose, radiation exposure, and morbidity in each space is presented. Finally, emerging applications and future directions are discussed. ^©RSNA, 2022.

Complicated Open Repair of Type B Aortic Dissection in a Patient With Ehlers-Danlos Syndrome Rescued by Endovascular Intervention

Ehlers-Danlos is a connective tissue disorder characterized by hypermobile joints, hyperextensible skin, and increased bleeding tendency. We report a case involving endovascular repair of an intussusception of aortic dissection that occurred in an Ehlers-Danlos patient following surgical repair of an intercostal artery bleed. Given the rarity of Ehlers-Danlos, continued reporting of treatment outcomes is important for refining complication management in this population. Our experience lends support for endovascular rescue of failed aortic repair that may arise in Ehlers-Danlos patients and contributes to the otherwise small body of literature concerning endovascular intervention in this population overall.

Review of Imaging With Focus on New Techniques in Aortic Dissection

The imaging evaluation of a patient with aortic dissection can be undoubtedly complex, requiring that the interpreting physician understands the classification systems and vocabulary used. This can be made all the more challenging by advances in medical imaging that reshape the understanding of aortic dissection. The purpose of this paper is to provide a review of recent advances in the imaging modalities, and select modality-specific technologies, commonly used to study aortic dissection, including computed tomography, magnetic resonance imaging, and ultrasound. This is followed by an overview of imaging findings, including the classification, initial evaluation, and follow up, of aortic dissection.

Endovascular Management of Malperfusion Syndromes in Aortic Dissection

Malperfusion Syndrome (MPS) refers to inadequate perfusion of end organs secondary to ongoing arterial obstruction of the aorta and its branches resulting in increased morbidity and mortality. While uncomplicated type B dissection can typically be monitored, type A or type B dissections with malperfusion syndrome are should be considered for hybrid treatment with an endovascular intervention.  In addition to pre-procedure CTA and labs, intra-procedure evaluation of the true lumen, false lumen, and branch vessels is performed with intravascular ultrasound (IVUS) and manometry to delineate static versus dynamic obstruction. Dynamic obstruction of the visceral arteries is typically treated first and can be relieved either with supraceliac dissection flap fenestration or exclusion of the entry tear by thoracic endovascular aortic repair, both of which will restore flow to the true lumen. Static obstruction requires stenting or other branch-artery intervention including branch artery fenestration, suction embolectomy, or thrombolysis. Throughout the procedure, IVUS and manometry are used to evaluate results of interventions with respect to continued hemodynamically significant obstruction. Endovascular intervention should be performed in conjunction with a multi-disciplinary team as patients are often complex and may require further procedures such as bowel resection or open aortic repair.

Update in aortic dissection

New concepts regarding the diagnosis, classification, and treatment of aortic dissection have been recently developed. The aim of this paper is to describe the current state of knowledge on this subject and discuss any controversies surrounding it. Novel findings in the patho mechanisms of aortic dissection have evolved focusing on the indications for preventive surgery, biomarkers, and four-dimensional (4D)-flow magnetic resonance imaging. New classifications of aortic dissections have been proposed (TEM, STS/SVS). Finally, recent treatment improvements in aortic dissection treatment options have been presented, i.e., the frozen elephant trunk approach, thoracic endovascular repair, and the endo-Bentall concept as a future option.

Distal Aortic Remodeling after Type A Dissection Repair: An Ongoing Mirage

Remodeling is a commonly encountered term in the field of cardiothoracic surgery that is often used to describe various pathophysiological changes in the dimension, structure, and function of various cardiac chambers, including the aorta. Stanford type A or DeBakey type 1 aortic dissection (TAAD) is a perplexing pathologic condition that can present surgical teams with the need to navigate a maze of complex decision-making. Ascending or hemi-arch replacement leaves behind a significant amount of distal diseased aortic tissue, which might have a persistent false lumen or primary or secondary intimal tears (or communications between lumina), which can lead to dilatation of the aortic arch. Unfavorable aortic remodeling is a major cause of distal aortic deterioration after the index surgery. Cardiac surgeons are aware of post-surgical cardiac chamber remodeling, but the concept of distal aortic remodeling is still idealized. The contemporary literature from established aortic centers supports aggressive management of the residual aortic pathology during the index surgery, and with continuing technical advancements, endovascular stenting options are readily available for patients with TAAD or for complicated type B aortic dissection cases. This review discusses the pathophysiology and treatment options for favorable distal aortic remodeling, as well as its impact on mid- to long-term outcomes following TAAD repair.

AT1R Regulates Macrophage Polarization Through YAP and Regulates Aortic Dissection Incidence

Aortic dissection (AD) is one of the most fatal cardiovascular emergency. At the anatomical level, AD occurs due to the formation of intimal tears. However, the molecular mechanism underlying this phenomenon remains unknown. Angiotensin II (Ang II) is a important effector in the development of cardiovascular disease that acts through binding to angiotensin type 1 receptor (AT1R). Yes-associated protein (YAP) was recently recognized as a key protein in macrophage activation. To determine whether AT1R and YAP are involved in macrophage-induced endothelial cell (EC) inflammation and AD incidence, we co-cultured THP-1 cells and HAECs in transwell chambers under different culture conditions and apply different conditions to the AD mice model. The results showed that Ang II promoted macrophage M1 polarization and adhesion, upregulated YAP phosphorylation, and induced EC injury that was related to increased levels of multiple pro-inflammatory chemokines. Blocking AT1R function pharmacologically or by transfection with AT1R siRNA can reduce the pro-inflammatory effect induced by Ang II. In addition, siRNA knock down of YAP expression further aggravated the pro-inflammatory effects of Ang II. Treatment with ARB effectively alleviated these pro-inflammatory effects. In the mice AD model, ARB effectively reduced the incidence of AD in mice, decreased M1 macrophages infiltration and AT1R content in the aortic wall and increased the tissue content of YAP. We found that AT1R induces YAP phosphorylation through binding to Ang II, and further promotes macrophage M1 polarization and adhesion to ECs. ARB reduces the incidence of AD in mice and affect macrophage polarization in mice aorta.

A Case of Effective Balloon Fenestration for Localized Aortic Dissection Complicated with Acute Renal and Bilateral Limb Ischemia in a Thoracoabdominal Aortic Aneurysm

An 85-year-old man visited our hospital with bilateral leg weakness. Blood tests revealed an abrupt deterioration of renal function. Computed tomography revealed a 53-mm aortic aneurysm at the level of the diaphragm with an aortic dissection after branching of the superior mesenteric artery. An emergency left axillary–left femoral artery bypass surgery was performed to secure blood flow to the kidneys and lower limbs. Five days later, a transcatheter balloon fenestration for the stenosis was performed, and the blood pressure of the infrarenal aorta was improved. Both the dorsal pedis and posterior tibial arteries became palpable, and renal function was improved.

Successfully superior mesenteric artery stenting in operated type A aortic dissection complicated with delayed mesenteric malperfusion

Here, we describe a case of a 61-year-old male patient with acute type A aortic dissection involving the ascending aorta, aortic arch, descending aorta, and the abdominal aorta down to the iliac bifurcation with evidence of left common iliac artery occlusion. Computed tomography angiography revealed progressive dissection into the superior mesenteric artery and left renal artery with no clinical signs of mesenteric ischemia. Emergent ascending aortic reconstruction of the dissected aorta relieves the leg ischemia. On a postoperative day 9, the evolution was complicated by massive right hemothorax. Although the patient was hemodynamically stable after obtaining hemostasis, the patient developed paralytic ileus with a high elevated lactate level. Visceral malperfusion was not detected by exploratory laparotomy. Emergency abdominal aortic angiography revealed superior mesenteric artery intermittent occlusion, successfully treated by stenting implantation.

Wall Shear Stress Assessment of the False Lumen in Acute Type B Aortic Dissection Visualized by 4-Dimensional Flow Magnetic Resonance Imaging: An Ex-Vivo Study

BACKGROUND

Four-dimensional flow magnetic resonance imaging (4D flow MRI) can accurately visualize and quantify flow and provide hemodynamic information such as wall shear stress (WSS). This imaging technique can be used to obtain more insight in the hemodynamic changes during cardiac cycle in the true and false lumen of uncomplicated acute Type B Aortic Dissection (TBAD). Gaining more insight of these forces in the false lumen in uncomplicated TBAD during optimal medical treatment, might result in prediction of adverse outcomes.

METHODS

A porcine aorta dissection model with an artificial dissection was positioned in a validated ex-vivo circulatory system with physiological pulsatile flow. 4D flow MR images with 3 set heartrates (HR; 60 bpm, 80 bpm and 100 bpm) were acquired. False lumen volume per cycle (FLV), mean and peak systolic WSS were determined from 4D flow MRI data. For validation, the experiment was repeated with a second porcine aorta dissection model.

RESULTS

During both experiments an increase in FLV (initial experiment: ΔFLV = 2.05 ml, p < 0.001, repeated experiment: ΔFLV = 1.08 ml, p = 0.005) and peak WSS (initial experiment: ΔWSS = 1.2 Pa, p = 0.004, repeated experiment: ΔWSS = 1.79 Pa, p = 0.016) was observed when HR increased from 60 to 80 bpm. Raising the HR from 80 to 100 bpm, no significant increase in FLV (p = 0.073, p = 0.139) was seen during both experiments. The false lumen mean WSS increased significant during initial (2.71 to 3.85 Pa; p = 0.013) and non-significant during repeated experiment (3.22 to 4.00 Pa; p = 0.320).

CONCLUSION

4D flow MRI provides insight into hemodynamic dimensions including WSS. Our ex-vivo experiments showed that an increase in HR from 60 to 80 bpm resulted in a significant increase of FLV and WSS of the false lumen. We suggest that strict heart rate control is of major importance to reduce the mean and peak WSS in uncomplicated acute TBAD. Because of the limitations of an ex-vivo study, 4D flow MRI will have to be performed in clinical setting to determine whether this imaging model would be of value to predict the course of uncomplicated TBAD.

A Novel Vascular-Friendly Thoracic Stent Graft for Endovascular Repair of Acute Complicated Type B Aortic Dissection

Purpose: To evaluate the safety and efficacy of a novel vascular-friendly thoracic stent graft for patients with acute complicated type B aortic dissection (ac-TBAD).

Methods: A multicenter retrospective study was undertaken in which we prospectively collected data in consecutive ac-TBAD patients treated by thoracic endovascular aortic repair (TEVAR) with the Ankura Thoracic Stent. Complications, true lumen rate (TLR), and mortality were recorded. Follow-up computed tomography angiography (CTA) was performed at 1, 6, and 12 months postoperatively and yearly thereafter.

Results: Altogether, 63 patients with ac-TBAD in four medical centers were included. No deaths or serious complications occurred during the perioperative period. The mean follow-up time was 30.1 ± 18.9 months. All-cause mortality rate was 3.1% (n = 2). TEVAR-related mortality rate was 1.6% (n = 1) because of retrograde type A dissection (RTAD) at 6 months. The other death was caused by acute myocardial infarction (AMI) during the third postoperative month. A distal endoleak detected at 3 months in one patient (1.6%) was treated by reintervention. The use of this novel vascular-friendly thoracic stent graft in ac-TBAD postoperative patients significantly improved their TLR.

Conclusion: The novel vascular-friendly thoracic stent graft showed satisfactory results, with favorable stability of the aortic diameter during follow-up.

[Treatment of a patient with acute thoracoabdominal aortic dissection complicated by haemothorax]

Total left-sided haemothorax is a rare and severe complication of acute DeBakey type III aortic dissection. The primary aim of treatment is immediate arrest of haemorrhage and stabilization of the haemodynamic status of the patient. Endovascular isolation of the ruptured thoracic portion of the aorta using a stent graft (TEVAR) has recently become the 'gold standard' in treatment of acute, rupture-complicated aortic dissections of this localization. Described in the article is a clinical case report concerning successful endovascular treatment of a seriously ill patient with dissection of the thoracoabdominal portion of the aorta, rupture and massive haemorrhage into the left pleural cavity. The patient underwent endoprosthetic repair of the descending aorta in the setting of a hybrid operating room under local anaesthesia, followed by drainage of the left pleural cavity. The postoperative period was uneventful with no complications. The patient was discharged in a satisfactory condition on day 10 after the emergency surgical intervention. An important advantage of TEVAR for aortic ruptures is a minimally invasive nature of the procedure, consisting in no need to perform either sternothoracotomy or to connect a heart-lung machine, thus decreasing surgical wound, reducing the risk of perioperative life-threatening haemorrhage, and contributing to early activation of the patient.

A rare cause of ischemic stroke in childhood: spontaneous long segment intracranial dissection

Craniocervical arterial dissection is an important cause of arterial ischemic stroke in children. Recognition of dissections is of particular importance both in determining the risk of recurrence and in bringing about different treatment alternatives. We report a 10-year-old girl who presented with acute ischemic stroke due to spontaneous long segment dissection involving the parasellar internal carotid artery up to the distal M1 portion of the middle cerebral artery. Three-dimensional digital subtraction angiography with flat panel detector revealed the presence of major vessels originating from both true and false lumens and had a critical role in the treatment decision of the case.

The Role of Macrophages in Aortic Dissection

Aortic dissection (AD) is a fatal disease that accounts for a large proportion of aortic-related deaths and has an incidence of about 3–4 per 100,000 individuals every year. Recent studies have found that inflammation plays an important role in the development of AD, and that macrophages are the hub of inflammation in the aortic wall. Aortic samples from AD patients reveal a large amount of macrophage infiltration. The sites of macrophage infiltration and activity vary throughout the different stages of AD, with involvement even in the tissue repair phase of AD. Angiotensin II has been shown to be an important factor in the stimulation of macrophage activity. Stimulated macrophages can secrete metalloproteinases, inflammatory factors and other substances to cause matrix destruction, smooth muscle cell apoptosis, neovascularization and more, all of which destroy the aortic wall structure. At the same time, there are a number of factors that regulate macrophages to reduce the formation of AD and induce the repair of torn aortic tissues. The aim of this review is to take a close look at the roles of macrophages throughout the course of AD disease.