Lower limb malperfusion in type B aortic dissection: a systematic review

Risk factors for severe acute kidney injury post complication after total arch replacement combined with frozen elephant trunk, in acute type A aortic dissection

Background

Total arch replacement with the frozen elephant trunk (TAR + FET) technique is a challenging approach for acute type A aortic dissection (ATAAD). Severe acute kidney injury (AKI) adversely affects the prognosis of hospitalized patients. The study aims to evaluate the incidence and risk factors of severe AKI.

Methods

We conducted a retrospective cross-sectional study of the records of ATAAD patients following TAR + FET, admitted between January 2013 and December 2018. A multivariate logistic regression model was used to identify predictors of severe postoperative AKI. Severe postoperative AKI was defined using the Kidney Disease Improving Global Outcomes criteria.

Results

The whole in-hospital mortality rate was 4.3%. Among 670 patients, major adverse outcomes were present in 169 patients (25.2%), 67 patients (10.0%) required renal replacement therapy (RRT), and 80 (11.9%) developed severe postoperative AKI. In-hospital mortality in the severe AKI group (13.8%) was 4.5 times higher than in the non-severe AKI group (3.1%). Compared with the non-severe AKI patients, the severe AKI patients had a higher incidence of major adverse outcomes (100% vs. 15.1%, P<0.001) and more frequent use of RRT (83.8% vs. 0.0%, P<0.001). Multivariate analysis revealed that severe postoperative AKI was predicted by advanced age [odds ratio (OR) =1.029; 95% confidence interval (CI): 1.002-1.056; P=0.032], lower limb symptoms (OR =4.384; 95% CI: 2.240-8.582; P<0.001), coronary artery involvement (OR =2.478; 95% CI: 1.432-4.288; P=0.001), preoperative postoperative serum creatinine (SCr) (OR =1.008; 95% CI: 1.003-1.013; P=0.001), and prolonged cardiopulmonary bypass (CPB) time (OR =1.011; 95% CI: 1.006-1.015; P<0.001).

Conclusions

There was a high incidence of severe AKI and high in-hospital mortality after TAR + FET in ATAAD patients. The risk factors for severe AKI in ATAAD patients undergoing TAR + FET were determined to help identify the high-risk patients and make rational treatment decisions.

Thoracic Endovascular Aortic Repair (TEVAR) First in Patients with Lower Limb Ischemia in Complicated Type B Aortic Dissection: Clinical Outcome and Morphology

Acute Type B aortic dissection (TBAD) can cause organ malperfusion, e.g., lower limb ischemia (LLI). Thoracic endovascular aortic repair (TEVAR) represents the standard treatment for complicated TBAD; however, with respect to LLI, data is scant. The aim of this study was to investigate clinical and morphological outcomes in patients with complicated TBAD and LLI managed with a "TEVAR-first" policy. Between March 1997 and December 2021, 731 TEVAR-procedures were performed, including 106 TBAD-cases. Cases with TBAD + LLI were included in this retrospective analysis. Study endpoints were morphological/clinical success of TEVAR, regarding aortic and extremity-related outcome, including extremity-related adjunct procedures (erAP) during a median FU of 28.68 months. A total of 20/106 TBAD-cases (18.8%, 32-82 years, 7 women) presented with acute LLI (12/20 Rutherford class IIb/III). In 15/20 cases, true lumen-collapse (TLC) was present below the aortic bifurcation. In 16/20 cases, TEVAR alone resolved LLI. In the remaining four cases, erAP was necessary. A morphological analysis showed a relation between lower starting point and lesser extent of TLC and TEVAR success. No extremity-related reinterventions and only one major amputation was needed. The data strongly suggest that aTEVAR-first-strategy for treating TBAD with LLI is reasonable. Morphological parameters might be of importance to anticipate the failure of TEVAR alone.

Prescreening and treatment of aortic dissection through an analysis of infinite-dimension data

Background

Aortic dissection (AD) is one of the most catastrophic aortic diseases associated with a high mortality rate. In contrast to the advances in most cardiovascular diseases, both the incidence and in-hospital mortality rate of AD have experienced deviant increases over the past 20 years, highlighting the need for fresh prospects on the prescreening and in-hospital treatment strategies.

Methods

Through two cross-sectional studies, we adopt image recognition techniques to identify pre-disease aortic morphology for prior diagnoses; assuming that AD has occurred, we employ functional data analysis to determine the optimal timing for BP and HR interventions to offer the highest possible survival rate.

Results

Compared with the healthy control group, the aortic centerline is significantly more slumped for the AD group. Further, controlling patients’ blood pressure and heart rate according to the likelihood of adverse events can offer the highest possible survival probability.

Conclusions

The degree of slumpness is introduced to depict aortic morphological changes comprehensively. The morphology-based prediction model is associated with an improvement in the predictive accuracy of the prescreening of AD. The dynamic model reveals that blood pressure and heart rate variations have a strong predictive power for adverse events, confirming this model’s ability to improve AD management.

Supplementary Information

The online version contains supplementary material available at (10.1186/s13040-021-00249-8).

Repeated Peripheral Embolisms associated with Chronic Aortic Dissection

A male patient developed acute type B aortic dissection (AD) extending to the right external iliac artery (EIA) and left common femoral artery at the age of 56 years. Two months after the diagnosis of AD, he developed right renal infarction suggesting embolism, as the right renal artery arose from a false lumen containing a mural thrombus. Seven years later, at the age of 63 years, the patient was readmitted for acute onset of intermittent claudication in the right leg. On admission, arterial pulses distal to the right femoral artery were absent. The right ankle-brachial pressure index (ABI) was 0.66, while the left ABI was 1.06. Computed tomography (CT) confirmed chronic type B AD and revealed a localized occlusion of the right EIA and disappearance of a small protruding thrombus in the false lumen that was found on the previous CT, suggesting a second embolism. Since recovery of antegrade blood flow was insufficient after catheter embolectomy, femorofemoral bypass was performed with resolution of ischemic symptoms. Postoperatively, the ABI recovered to 0.99 in the right and 1.12 in the left, and CT showed a patent bypass graft and restoration of blood flow to the right leg. This case indicates that embolism should be recognized as one of the possible causes of acute organ ischemia in patients with AD, even in patients with chronic AD.

Multilayer flow modulator enhances vital organ perfusion in patients with type B aortic dissection

Management of aortic dissections (AD) is still challenging, with no universally approved guideline among possible surgical, endovascular, or medical therapies. Approximately 25% of patients with AD suffer postintervention malperfusion syndrome or hemodynamic instability, with the risk of sudden death if left untreated. Part of the issue is that vascular implants may themselves induce flow disturbances that critically impact vital organs. A multilayer mesh construct might obviate the induced flow disturbances, and it is this concept we investigated. We used preintervention and post-multilayer flow modulator implantation (PM) geometries from clinical cases of type B AD. In-house semiautomatic segmentation routines were applied to computed tomography images to reconstruct the lumen. The device was numerically reconstructed and adapted to the PM geometry concentrically fit to the true lumen centerline. We also numerically designed a pseudohealthy case, where the geometry of the aorta was extracted interpolating geometric features of preintervention, postimplantation, and published representative healthy volunteers. Computational fluid dynamics methods were used to study the time-dependent flow patterns, shear stress metrics, and perfusion to vital organs. A three-element Windkessel lumped parameter module was coupled to a finite-volume solver to assign dynamic outlet boundary conditions. Multilayer flow modulator not only significantly reduced false lumen blood flow, eliminated local flow disturbances, and globally regulated wall shear stress distribution but also maintained physiological perfusion to peripheral vital organs. We propose further investigation to focus the management of AD on both modulation of blood flow and restoration of physiologic end-organ perfusion rather than mere restoration of vascular lamina morphology. NEW & NOTEWORTHY The majority of aortic dissection modeling efforts have focused on the maintenance of physiological flow using minimally invasive placed grafts. The multilayer flow modulator is a complex mesh construct of wires, designed to eliminate flow disruptions in the lumen, regulate the physiological wall stresses, and enhance endothelial function and offering the promise of improved perfusion of vital organs. This has never been fully proved or modeled, and these issues we confirmed using a dynamic framework of time-varying arterial waveforms.

Acute non-traumatic disease of the abdominal aorta

Acute pathology in the abdominal aorta is associated with significant morbidity and mortality. The most feared complication of abdominal aortic disease is acute rupture in the setting of atherosclerotic abdominal aortic aneurysm. Although frank rupture often is easily diagnosed on CT, other findings such as a hyperattenuating crescent, discontinuous intimal calcium, and draping of the aorta are subtle signs of aneurysm instability. A true aneurysm should be distinguished from a rapidly growing, saccular pseudoaneurysm in the setting of infectious aortitis, as treatment strategy differs. Acute aortic syndrome involving the abdominal aorta, such as dissection and intramural hematoma, often is an extension of thoracic aortic disease, whereas penetrating atherosclerotic ulcers occasionally involve only the abdominal aorta. The goal of treating acute aortic pathology is to repair and prevent rupture, as well as restore and maintain perfusion of the lower extremities, kidneys, and mesentery. However, both open and endovascular repair of the abdominal aorta may become acutely complicated, resulting in compromise of these goals. Examples include aortoenteric fistula, endoleak, anastomotic pseudoaneurysm, graft infection, and thrombosis or kinking of a stent graft resulting in ischemia of the limbs and mesentery.

Acute Type B Dissection Causing Collapse of EVAR Endograft and Iliac Limb Occlusion

We describe a rare case of acute type B dissection (ATBDs) causing collapse of a previously placed infrarenal stent graft, resulting in acute limb ischemia due to left iliac limb thrombosis in a 59-year-old male. The patient presented with acute back and abdominal discomfort radiating to his back, bilateral buttock stabbing discomfort and left > right thigh and calf rest pain. CT angiography showed a spiral type B dissection with collapse of the proximal portion of the endovascular repair of aortic aneurysm (EVAR) device and left limb occlusion. Urgent treatment with thoracic endovascular aortic repair distal to the left subclavian covered the entry tear and redirected the majority of the flow to the true lumen leading to near immediate expansion of the proximal portion of the EVAR device. After surgical femoral control, balloon embolectomy of the occluded iliac limb was performed and the limb relined. His lower extremity ischemic symptoms resolved, and his abdominal and back pain dissipated. At latest 6-month follow-up, CT angiography shows an intact thoracic endovascular aortic repair stent graft and a widely patent EVAR stent graft, and the patient has no further abdominal, back, or leg symptoms. ATBD causing proximal abdominal EVAR collapse is an extremely rare presentation of false lumen pressurization and can be treated similarly to complicated type B dissection with the goal of restoring true lumen patency.

Malperfusion syndromes in aortic dissections

Aortic dissection remains a challenging clinical scenario, especially when complicated by peripheral malperfusion. Improvements in medical imaging have furthered understanding of the pathophysiology of malperfusion events in association with aortic dissection, including the elucidation of different mechanisms of branch vessel obstruction. Despite these advances, malperfusion syndrome remains a deadly entity with significant mortality. This review presents the latest knowledge regarding the pathogenesis of aortic dissection complicated by malperfusion syndrome, and discusses the diagnostic and therapeutic guidelines for management of this vicious entity.

Successful Endovascular Stent-Graft Repair for Complicated Type B Aortic Dissection Developed in a Patient with Polycystic Kidney Disease

Polycystic kidney disease (PCKD) is rarely associated with aortic dissection (AD), which is a life-threatening disease. Although endovascular stent-graft repair tends to show better outcomes than conventional therapies in complicated type B AD (TBAD), successful endovascular intervention of TBAD with malperfusion in a patient with PCKD has not been reported. This case shows a 37-year-old male who had sudden onset of sharply stabbing epigastric pain with severe hypertension, who was diagnosed with TBAD and PCKD by a computed tomography and initially underwent medical treatment. Four days after discharge, he was rehospitalized with left leg pain and paresthesia due to left lower leg malperfusion. Thoracic endovascular stent-graft repair covering the primary tear site of dissection was performed successfully, leading to a decrease in false lumen and improvement of symptoms. We report the case of complicated TBAD in a patient with PCKD treated with endovascular stent-graft repair.

Aortic fenestration for type B chronic aortic dissection complicated with lower limb malperfusion induced by walking exercise

We report a case of a 55-year-old male with type B-chronic aortic dissection. Patient presented with intermittent claudication due to limb malperfusion resulting from expansion of a patent false lumen during walking regardless of normal range ankle-brachial index (ABI) at rest. Preoperative stress vascular ultrasonography was an effective modality for proper diagnosis. We should be concerned of reversible ischemia due to the dissection flap in patients with type B aortic dissection. Fenestration of the aorta can be a choice of treatment in such patients. The patient has been doing well with no ischemia for 3.5 years after the operation.