Acute type B aortic dissection: insights from the International Registry of Acute Aortic Dissection

Assessment of the re-entry tear index as a prognostic indicator for renal perfusion improvement after thoracic endovascular aortic repair in patients with acute and subacute Stanford type b aortic dissection with renal artery involvement

Background

Aortic dissection is the most common acute aortic syndrome, and renal artery is the most common involved artery. The size and location of the re-entry tear directly affect the blood flow enhancement of the false lumen branch artery after surgery. In this study, the morphology and hemodynamics of the re-entry tear were comprehensively analyzed, and the location and size of the re-entry tear were quantitatively evaluated to calculate the re-entry tear index (RTI). This study aimed to assess the predictive capability of a comprehensive quantitative RTI for improvement in renal perfusion following thoracic endovascular aortic repair (TEVAR) in cases of acute and subacute Stanford type B aortic dissection with renal artery involvement.

Methods

In this prospective cohort study, 137 patients diagnosed with acute or subacute type B aortic dissection with concomitant renal artery involvement who underwent TEVAR at Anzhen Hospital in Beijing from October 2017 to November 2021 were enrolled. Renal blood flow was estimated quantitatively with ultrasound. Based on the ultrasound findings of renal artery flow, the patients were classified into two groups: group A [postoperative volume flow (VolFlow) reduced compared to preoperative VolFlow] and group B (postoperative VolFlow increased compared to preoperative VolFlow). All re-entry tears present in the aortic trunk according to reconstructed computed tomography angiography (CTA) obtained preoperatively were included in the analysis. The general information of patients, whether the involved renal artery arose partially or wholly from the false lumen, the proximal diameter and length of the covered stent, the diameter of primary entry tear, the RTI, etc. were analyzed. Univariate and multivariate logistic regression analyses were executed to assess the risk factors associated with increased renal arterial blood flow subsequent to TEVAR. Additionally, receiver operating characteristic (ROC) curve analysis was used to ascertain the optimal cutoff value and predictive efficacy of the RTI.

Results

A total of 137 patients, comprising of 32 with acute and 105 with subacute type B aortic dissection accompanied by renal artery involvement, underwent TEVAR. Among these patients, 44 (32.1%) were assigned to group A and 93 (67.9%) to group B. Renal blood flow exhibited an increase in 67.9% of the patients after TEVAR. The results of multivariate analysis indicated that the RTI is an independent risk factor for postoperative renal perfusion improvement [odds ratio =17.66; 95% confidence interval (CI): 2.13-78.55; P=0.020]. The optimal cutoff value for RTI, determined to be 0.033, demonstrated the ability to identify renal perfusion improvement in patients without hypertension with a sensitivity of 53.7% and a specificity of 68.9%. In patients with concomitant hypertension, RTI exhibited a sensitivity of 96.6% and a specificity of 60.0%, with an area under the ROC curve (AUC) of 0.792 (95% CI: 0.643-0.941; P=0.021) for identifying renal perfusion improvement.

Conclusions

RTI demonstrated a favorable predictive value for improving renal malperfusion following TEVAR in cases of aortic dissection with renal artery involvement.

Losing, regaining, and continuing to build self-confidence - a qualitative, phenomenological study of being physically active with a type B aortic dissection

PURPOSE

To gain a comprehensive understanding of experiences related to being physically active in participants with an uncomplicated type B aortic dissection.

MATERIALS AND METHODS

We performed a qualitative, phenomenological study. First-person accounts of adults, who at least one year ago had an uncomplicated type B aortic dissection, were collected using semi-structured interviews. The audio recordings of the interviews were transcribed verbatim and analyzed with interpretative phenomenological analysis.

RESULTS

We collected, in total, 644 min interview data from 14 participants. Three patterns were interpreted: losing self-confidence, regaining self-confidence, and continuing to build self-confidence. Experiencing symptoms when pushing limits, challenges with energy management, and side effects of medication caused loss of self-confidence. Changes in identity, reaching milestones that reflect improvement, and support from others and tools helped participants regain self-confidence. To continuing to build self-confidence, participants indicated they needed success experiences and activities make life worth living.

CONCLUSIONS

Self-confidence in adults with an uncomplicated type B aortic dissection changes immediately after the diagnosis of the aortic dissection. Rehabilitation professionals can support adults regaining and continuing to build self-confidence, aiming for the perfect balance between blood pressure regulation, quality of life, and being physically active.Implications for rehabilitationRehabilitation professionals should support regaining and continuing to build self-confidence related to being physically active in adults with type B aortic dissection in the early stages of recovery and beyond.Adults with an uncomplicated type B aortic dissection want rehabilitation professionals to tell them primarily what is possible (recommendations) rather than what is not allowed (rules).Rehabilitation professionals should help adults with an uncomplicated type B aortic dissection to explore, push and, ultimately, accept limits related to exercise tolerance.

Predicting adverse events after thoracic endovascular aortic repair for patients with type B aortic dissection

The potential of adverse events (AEs) after thoracic endovascular aortic repair (TEVAR) in patients with type B aortic dissection (TBAD) has been reported. To avoid the occurrence of AEs, it is important to recognize high-risk population for prevention in advance. The data of 261 patients with TBAD who received TEVAR between June 2017 and June 2021 at our medical center were retrospectively reviewed. After the implementation of exclusion criteria, 172 patients were finally included, and after 2.8 years (range from 1 day to 5.8 years) of follow up, they were divided into AEs (n = 41) and non-AEs (n = 131) groups. We identified the predictors of AEs, and a prediction model was constructed to calculate the specific risk of postoperative AEs at 1, 2, and 3 years, and to stratify patients into high-risk (n = 78) and low-risk (n = 94) group. The prediction model included seven predictors: Age > 75 years, Lower extremity malperfusion (LEM), NT-proBNP > 330 pg/ml, None distal tear, the ratio between the diameter of the ascending aorta and descending aorta (A/D ratio) > 1.2, the ratio of the area of the false lumen to the total aorta (FL ratio) > 64%, and acute TEVAR, which exhibited excellent predictive accuracy performance and discriminatory ability with C statistic of 82.3% (95% CI 77.3-89.2%). The prediction model was contributed to identify high-risk patients of postoperative AEs, which may serve to achievement of personalized treatment and follow-up plans for patients.

Prognostic Value of the Systemic Immune Inflammation Index after Thoracic Endovascular Aortic Repair in Patients with Type B Aortic Dissection

The study aimed at investigating the association between postoperative inflammatory scores and aorta-related adverse events (AAEs) after thoracic endovascular aortic repair (TEVAR) for patients with type B aortic dissection (TBAD). This single-centre, retrospective cohort included all patients who underwent TEVAR for TBAD between November 2016 and November 2020 at a university hospital. The risk factors for AAEs were analyzed by Cox proportional hazards model regression. Prediction accuracy was assessed using the area under the receiver operating characteristic curves. This study included 186 patients with a mean age of 58.5 years and a median follow-up period of 26 months. A total of 68 patients developed AAEs. Age and postoperative systemic immune inflammation index (SII) (>2893) were associated with post-TEVAR AAEs (hazard ratio (HR) 1.03, p = 0.003; HR 1.88, p = 0.043, respectively). Increased postoperative SII and age are independent risk factors for AAE post-TEVAR in patients with TBAD.

Prognostic value of interleukin-33, sST2, myeloperoxidase, and matrix metalloproteinase-9 in acute aortic dissection

Background and purpose

Acute aortic dissection (AAD) is a life-threatening cardiovascular emergency. Both neutrophil granzyme and interleukin (IL)-33/ST2 systems have proven to be effective diagnostic markers for AAD. This study aimed to investigate the relationship between plasma IL-33, soluble suppression of tumorigenesis-2 (sST2), myeloperoxidase (MPO), and matrix metalloproteinase (MMP)-9 levels at admission and all-cause mortality in patients with AAD.

Methods

A total of 155 patients with AAD were enrolled from the Prospective Evaluation of Acute Chest Pain (PEACP) study. Plasma concentrations of IL-33, sST2, and MMP-9 were measured using an enzyme-linked immunosorbent assay, and MPO was detected using a chemiluminescence immunoassay. Aortic anatomical parameters were measured using CT radiography. The primary endpoint was all-cause mortality rate.

Results

The median age of the patients was 55 years, and 96 (61.9%) were diagnosed with type A-AAD. After adjusting for confounding factors, the highest tertiles of IL-33, sST2, MPO, and MMP-9 had hazard risks of 0.870 (95% CI: 0.412-1.836, P = 0.714), 3.769 (95% CI: 1.504-9.446, P = 0.005), 4.689 (95% CI: 1.985-11.076, P < 0.001), and 4.748 (95% CI: 1.763-12.784, P = 0.002), respectively, compared to the lowest tertile. Pearson's correlation analysis revealed a significant correlation between these markers (P < 0.001). Moreover, sST2, MPO, and MMP-9 levels had a significant positive correlation with aortic diameter and pseudolumen area (P < 0.001).

Conclusion

The biomarkers sST2, MPO, and MMP-9 were independently associated with mortality in patients with AAD. The significant correlation between these biomarkers suggests a pathogenic role for the IL-33/ST2/neutrophil granzyme system in patients with AAD.

Emergency Endovascular Interventions on Descending Thoracic Aorta: A Single-Center Experience

Background

Implementation of emergency endovascular aortic repair provides an attractive opportunity in the treatment of complicated acute aortic syndromes involving descending aorta.

Aim

The aim of this study was to analyze the effectiveness of thoracic endovascular aortic repair (TEVAR) for the treatment of acute surgical emergencies involving the descending thoracic aorta.

Methods

A retrospective review of the medical records of all patients undergoing TEVAR in a single center since 2007 was undertaken. Patients with the aortic disease treated on emergency inclusion criteria were complicated spontaneous acute aortic syndrome (csAAS), traumatic aortic acute injuries (TAIs), and other indications requiring emergent intervention. Technical and clinical success with patient mortality, survival, and reoperation rate was evaluated according to Society for Vascular Surgery reporting standards for thoracic endovascular aortic repair (TEVAR).

Results

The emergency interventions were necessary in 74 cases (51.0%), including patients with the complicated spontaneous acute aortic syndrome (csAAS) (64.8%; n = 48) and traumatic aortic acute injuries (TAIs) (31.1%). In addition, in one case aortic iatrogenic dissection (AID) and in 2 other fistulas after the previous stent graft, implantations were diagnosed. All procedures were done through surgically exposed femoral arteries while 2 hybrid procedures required additional approaches. The primary technical success rate was 95.9%, in 3 cases endoleak was reported. The primary clinical success occurred in 94.5%. All patients survived the endovascular interventions, whereas during in-hospital stay one of them died due to multiorgan failure (early mortality 1.3%). During the follow-up period, lasting 6 through 164 months (median 67), 11 patients died. Annual, five- and ten-year probability of survival was 86.4 ± 0.04%, 80.0 ± 0.05%, and 76.6 ± 0.06%, respectively. However, the rate of 5-year survivors was significantly higher after TAI (95.2%) than scAAS (63.4%) (p=0.008). Early after the procedure, one individual developed transient paraparesis (1.3%). No other serious stent-graft-related adverse events were noted within the postdischarge follow-up period.

Conclusions

Descending aortic pathologies requiring emergent interventions can be treated by endovascular techniques with optimal results and low morbidity and mortality in an experienced and dedicated team.

Outcomes of supra coronary aortic repair technique in patients with acute aortic dissection type A

BACKGROUND

Acute aortic dissection type A (AADA) is a fatal event that requires an emergent surgical operation. Here, we decided to evaluate the outcome of supra coronary aortic repair technique in patients with type A acute aortic dissection for 16 years in Isfahan Chamran hospital that one surgeon performed.

METHODS

This is a retrospective descriptive cross-sectional study performed in 2019 in Isfahan on documents of 54 patients who underwent supra-coronary repair surgery for type A aortic dissection during 2004 to 2019. We collected patient's demographic information, the condition of patient's vital signs at the time of admission to the hospital and before surgery, the cardiopulmonary bypass (CPB) time and other variables. We also collected data regarding patient's mortality and possible surgical complications.

RESULTS

Evaluation of surgical complications showed that acute renal failure (ARF) was the most common complication (87%) followed by postoperative bleeding in ICU that required surgical operation (18.5%), neurologic complications (13%), acute respiratory distress syndrome (ARDS) (9.3%) and chronic renal failure (CRF) (1.9%). The mortality rate was 14.8% (8 patients). The most frequent reason for mortality was bleeding (50%), major neurologic complications (37.5%), multiple organ failure (25%), cardiac failure (12.5%) and CRF (12.5%). Patients with mortality had significantly higher age compared to other patients (P = 0.03), significantly higher duration of CPB use (P = 0.03), higher frequency of irregular peripheral pulses (P = 0.01), higher frequency of abnormal carotid pulses (P = 0.04), and higher bleeding volume in the ICU (P = 0.04).

CONCLUSION

Age, disturbed preoperative clinical condition, postoperative bleeding, and organ failure could increase the rates of mortality of AADA.

An in vitro Assessment of the Haemodynamic Features Occurring Within the True and False Lumens Separated by a Dissection Flap for a Patient-Specific Type B Aortic Dissection

One of the highest mortality rates of cardiovascular diseases is aortic dissections with challenging treatment options. Currently, less study has been conducted in developing in vitro patient-specific Type B aortic dissection models, which mimic physiological flow conditions along the true and false lumens separated by a dissection flap with multiple entry and exit tears. A patient-specific Stanford Type B aortic dissection scan was replicated by an in-house manufactured automatic injection moulding system and a novel modelling technique for creating the ascending aorta, aortic arch, and descending aorta incorporating arterial branching, the true/false lumens, and dissection flap with entry and exit intimal tears. The physiological flowrates and pressure values were monitored, which identified jet stream fluid flows entering and exiting the dissection tears. Pressure in the aorta’s true lumen region was controlled at 125/85 mmHg for systolic and diastolic values. Pressure values were obtained in eight sections along the false lumen using a pressure transducer. The true lumen systolic pressure varied from 122 to 128 mmHg along the length. Flow patterns were monitored by ultrasound along 12 sections. Detailed images obtained from the ultrasound transducer probe showed varied flow patterns with one or multiple jet steam vortices along the aorta model. The dissection flap movement was assessed at four sections of the patient-specific aorta model. The displacement values of the flap varied from 0.5 to 3 mm along the model. This model provides a unique insight into aortic dissection flow patterns and pressure distributions. This dissection phantom model can be used to assess various treatment options based on the surgical, endovascular, or hybrid techniques.

Novel method for endovascular fenestration using radiofrequency transseptal needle for aortic dissection with malperfusion syndrome

Malperfusion syndrome is considered one of the most significant adverse events in aortic dissection disease and often requires invasive strategies to improve ischemia. We report the case of a patient who was presented with worsening claudication and leg rest pain due to malperfusion syndrome of type B aortic dissection. We successfully performed endovascular fenestration therapy to relieve the symptom by using a NRG radiofrequency transseptal needle (Baylis Medical, Montreal, Canada). We suggest that this novel method would be available for the patients with malperfusion syndrome of aortic dissection

Total Arch and Descending Aorta Replacement for Retrograde Type A Aortic Dissection After Endovascular Stent Graft Replacement for Complicated Type B Aortic Dissection

Retrograde type A aortic dissection (RTAD) is a severe complication of thoracic endovascular aortic repair (TEVAR). In this regard, we present our unique surgical methods for total arch and descending aorta replacement for RTAD after TEVAR for complicated type B aortic dissection (TBAD). A 52-year-old man with a history of distal arch large aneurysm was diagnosed with TBAD. Because he had sustained chest pain and his aneurysm diameter was 67 mm, TEVAR was urgently performed. After a right axillary-left axillary artery bypass, a stent graft was deployed in the descending aorta via the right femoral artery. Coil embolization was performed in the left subclavian artery. After the condition of the stent graft was checked by angiography, no Type 1 endoleak and backflow from the re-entry was observed. However, seven days after the operation, he experienced chest pain suddenly.

Computed tomography (CT) revealed forward blood flow in the descending aorta (type IA endoleak) and thrombosed aortic dissection in the ascending aorta. The distal arch diameter exceeded 70 mm. A decision was taken to immediately perform an operation. Total aortic arch and descending aorta replacement were performed through a median sternotomy with left 5th interspace thoracotomy. The operation was performed under deep hypothermic circulatory arrest, and selective antegrade cerebral perfusion was accomplished. As a result of the exploration of the aortic arch, it was found that the intimal injury by the bare stent caused RTAD. The patient was successfully extubated after the operation and was discharged without any complications. RTAD can present as an early complication after descending stent grafting because of aortic instability or due to the strength of bare stents. Aortic arch and descending aorta replacement after TEVAR via a clamshell incision can be safely performed if RTAD is diagnosed early.

Biomechanical Material Characterization of Stanford Type-B Dissected Porcine Aortas

Aortic dissection (AD) involves tearing of the medial layer, creating a blood-filled channel called false lumen (FL). To treat dissections, clinicians are using endovascular therapy using stent grafts to seal the FL. This procedure has been successful in reducing mortality but has failed in completely re-attaching the torn intimal layer. The use of computational analysis can predict the radial forces needed to devise stents that can treat ADs. To quantify the hyperelastic material behavior for therapy development, we harvested FL wall, true lumen (TL) wall, and intimal flap from the middle and distal part of five dissected aortas. Planar biaxial testing using multiple stretch protocols were conducted on tissue samples to quantify their deformation behavior. A novel non-linear regression model was used to fit data against Holzapfel–Gasser–Ogden hyperelastic strain energy function. The fitting analysis correlated the behavior of the FL and TL walls and the intimal flap to the stiffness observed during tensile loading. It was hypothesized that there is a variability in the stresses generated during loading among tissue specimens derived from different regions of the dissected aorta and hence, one should use region-specific material models when simulating type-B AD. From the data on material behavior analysis, the variability in the tissue specimens harvested from pigs was tabulated using stress and coefficient of variation (CV). The material response curves also compared the changes in compliance observed in the FL wall, TL wall, and intimal flap for middle and distal regions of the dissection. It was observed that for small stretch ratios, all the tissue specimens behaved isotropically with overlapping stress–stretch curves in both circumferential and axial directions. As the stretch ratios increased, we observed that most tissue specimens displayed different structural behaviors in axial and circumferential directions. This observation was very apparent in tissue specimens from mid FL region, less apparent in mid TL, distal FL, and distal flap tissues and least noticeable in tissue specimens harvested from mid flap. Lastly, using mixed model ANOVAS, it was concluded that there were significant differences between mid and distal regions along axial direction which were absent in the circumferential direction.

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.

[Complicated acute type B aortic dissection-what does endovascular therapy contribute?]

BACKGROUND

Acute aortic dissection type B is a severe and life-threatening vascular emergency. Complications such as rupture and/or malperfusion of organs are the main reasons for early mortality.

OBJECTIVES

The aim is to provide an overview on important diagnostic radiological findings, conservative as well as endovascular therapeutic options for patients presenting with rupture or malperfusion syndromes.

RESULTS

Medical treatment consisting of blood pressure and heart rate control as well las adequate analgesia remains the cornerstone therapy of all type B aortic dissections. In case of organ malperfusion, various endovascular therapies, e. g., endoluminal fenestration of dissection flap, thoracic stent-graft implantation (TEVAR) or branch vessel stenting, are available. In the case of aortic rupture, TEVAR has become the standard owing to its lower mortality compared to open surgical repair.

DISCUSSION

For the treatment of complicated type B aortic dissection, a number of endovascular options are available. For optimal treatment, profound knowledge of the disease, of the diagnostic workup, and of the interventional procedures is mandatory.

MYLK pathogenic variants aortic disease presentation, pregnancy risk, and characterization of pathogenic missense variants

Purpose

Heritable thoracic aortic disease (HTAD) can result from null variants in MYLK, which encodes myosin light chain kinase (MLCK). Data on which MYLK missense variants are pathogenic and information to guide aortic disease management are limited.

Methods

Clinical data from 33 cases with MYLK pathogenic variants were analyzed (5 null and 2 missense variants) and the effect of missense variants on kinase activity was assessed.

Results

Twenty-three individuals (39%) experienced an aortic event (defined as aneurysm repair or dissection); the majority of these events were aortic dissections (87%). Aortic diameters were minimally enlarged at the time of dissection in many cases. Time to aortic event curves showed missense mutation carriers have earlier onset aortic events than null mutation carriers. A MYLK missense variant segregated with aortic disease over five generations but only marginally decreases MLCK kinase activity, and functional assays fail to identify all pathogenic variants in MYLK.

Conclusions

These data further define aortic phenotype associated with MYLK pathogenic variants. Given minimal aortic enlargement prior to dissection, an alternative approach to guide the timing of aortic repair is proposed based the probability of a dissection at a given age.

Endovascular management of acute aortic dissection

Acute dissection of the thoracic aorta is a potentially life-threatening condition which requires collaborative treatment from multiple specialties for optimal patient outcomes. Dissections involving the ascending aorta and aortic arch have traditionally been managed entirely by surgery, while dissections beyond the arch vessels have most commonly been relegated to medical management. This algorithm has been undergoing a paradigm shift over the past two decades due to improvements in stent graft technology, better understanding of the hemodynamic interactions of the true and false lumen and their influence on organ and limb perfusion, and improvements in medical management and long term surveillance for dissection-related complications. This manuscript includes a brief discussion of the pathogenesis and etiology of dissection, followed by an in-depth review of the medical and endovascular techniques utilized to treat patients afflicted by this condition.

Recent evolution in use and effectiveness in mainland China of thoracic endovascular aortic repair of type B aortic dissection

A meta-analysis was performed on 175 studies selected among those published in mainland China between 2008 and 2015 on thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (AD). Most TEVAR were performed in Shanghai, Beijing, Hubei and Guangdong in patients with mean age of 53.9 years, and acute (70%) or chronic (30%) type B AD. Procedural success rate was 99.1 ± 0.8%. Major complication rate was 1.7 ± 2.3%, with paraplegia in 0.4 ± 0.0%. Overall in-hospital mortality rate was 1.6 ± 0.9% with AD rupture in 30% (about 40% during first postoperative day); follow-up mortality rate was 2.3 ± 1.1%, with AD rupture in 39.2% (50% within first year). Compared with 2001–2007 data from China, there appeared to be improvement in rates of major complications, paraplegia and in-hospital mortality. Compared with 1999–2004 Western data, rates of procedural success, stroke, and paraplegia appeared similar, while those for major complications, in-hospital mortality, retrograde type A dissection and follow-up mortality appeared lower. Compared with more recent Western data (2006–2013) on acute complicated type B AD, stroke, paraplegia, in-hospital mortality and follow-up mortality appeared lower. Therefore, in mainland China, safety for TEVAR of type B AD appeared better between 2008 and 2015 than in previous periods in China or Western countries.

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.

Intensive blood pressure control in patients with acute type B aortic dissection (RAID): study protocol for randomized controlled trial

BACKGROUND

Blood pressure control is an essential therapy for patients with acute type B aortic dissection (ABAD) and should be maintained throughout the entire treatment. Thus, vast majority current guidelines recommend control the blood pressure to lower than 140/90 mmHg. Theoretically, a much lower target may further decrease the risk of propagation of dissection. However, some argued that too lower blood pressure would compromise the organ perfusion. Thus, there is no unanimous optimal target for blood pressure in patients with ABAD so far. The present study aimed to investigate the optimal blood pressure target for patients with ABAD, in the hope that the result would optimize the treatment of aortic dissection (AD).

METHODS

The study is a multi-center randomized controlled clinical trial. Study population will include patients with new diagnosed ABAD and hypertension. Blocked randomization was performed where intensive blood pressure control (<120 mmHg) with conventional blood pressure control (<140 mmHg) were allocated at random in a ratio of 1:1 in blocks of sizes 4, 6, 8, and 10 to 360 subjects. Interim analysis will be performed. The primary outcome is a composite in-hospital adverse outcome, including death, permanent paraplegia or semi- paralysis during the hospitalization, and renal failure requiring hemodialysis at discharge. While the secondary outcomes include the aortic size, lower extremity or visceral ischemia, retrograde propagation into aortic arch or ascending aorta, mortality in 6 months and 1 year, intensive care unit (ICU) length of stay, total length of hospital stay, creatinine level, and surgical or endovascular intervention.

ETHICS AND DISSEMINATION

The study was approved by the institutional review board of Sir Run Run Shaw Hospital (approval number: 20160920-9). Informed consent will be obtained from participants or their next-of-kin. The results will be published in a peer-reviewed journal and shared with the worldwide medical community.

TRIAL REGISTRATION

NCT03001739 (https://register.clinicaltrials.gov/).

Blood groups and acute aortic dissection type III

INTRODUCTION

Acute aortic type III dissection is one of the most catastrophic events, with in-hospital mortality ranging between 10% and 12%. The majority of patients are treated medically, but complicated dissections, which represent 15% to 20% of cases, require surgical or thoracic endovascular aortic repair (TEVAR). For the best outcomes adequate blood transfusion support is required. Interest in the relationship between blood type and vascular disease has been established. The aim of our study is to evaluate distribution of blood groups among patients with acute aortic type III dissection and to identify any kind of relationship between blood type and patient's survival.

MATERIAL AND METHODS

From January 2005 to December 2014, 115 patients with acute aortic type III dissection were enrolled at the Clinic of Vascular and Endovascular Surgery in Belgrade, Serbia and retrospectively analyzed. Patients were separated into two groups. The examination group consisted of patients with a lethal outcome, and the control group consisted of patients who survived.

RESULTS

The analysis of the blood groups and RhD typing between groups did not reveal a statistically significant difference (p = 0.220).

CONCLUSIONS

Our results indicated no difference between different blood groups and RhD typing with respect to in-hospital mortality of patients with acute aortic dissection type III.

Role of Pulse Pressure and Geometry of Primary Entry Tear in Acute Type B Dissection Propagation

The hemodynamic and geometric factors leading to propagation of acute Type B dissections are poorly understood. The objective is to elucidate whether geometric and hemodynamic parameters increase the predilection for aortic dissection propagation. A pulse duplicator set-up was used on porcine aorta with a single entry tear. Mean pressures of 100 and 180 mmHg were used, with pulse pressures ranging from 40 to 200 mmHg. The propagation for varying geometric conditions (%circumference of the entry tear: 15–65%, axial length: 0.5–3.2 cm) were tested for two flap thicknesses (1/3rd and 2/3rd of the thickness of vessel wall, respectively). To assess the effect of pulse and mean pressure on flap dynamics, the %true lumen (TL) cross-sectional area of the entry tear were compared. The % circumference for propagation of thin flap (47 ± 1%) was not significantly different (p = 0.14) from thick flap (44 ± 2%). On the contrary, the axial length of propagation for thin flap (2.57 ± 0.15 cm) was significantly different (p < 0.05) from the thick flap (1.56 ± 0.10 cm). TL compression was observed during systolic phase. For a fixed geometry of entry tear (%circumference = 39 ± 2%; axial length = 1.43 ± 0.13 cm), mean pressure did not have significant (p = 0.84) effect on flap movement. Increase in pulse pressure resulted in a significant change (p = 0.02) in %TL area (52 ± 4%). The energy acting on the false lumen immediately before propagation was calculated as 75 ± 9 J/m² and was fairly uniform across different specimens. Pulse pressure had a significant effect on the flap movement in contrast to mean pressure. Hence, mitigation of pulse pressure and restriction of flap movement may be beneficial in patients with type B acute dissections.

Outcomes of Patients With Acute Type B (DeBakey III) Aortic Dissection: A 13-Year, Single-Center Experience

Background—

Aortic dissection remains the most common aortic catastrophe. In the endovascular era, the management of acute type B aortic dissection (ATBAD) is undergoing dramatic changes. The aim of this study is to evaluate the long-term outcomes of patients with ATBAD who were treated at our center over a 13-year period.

Methods and Results—

We reviewed patients with ATBAD between 2001 and 2014, analyzing variables based on status (complicated [c] versus uncomplicated [u]) and treatment modalities. We defined cATBAD as rupture, expansion of diameter on imaging during the admission, persistent pain, or clinical malperfusion leading to a deficit in cerebral, spinal, visceral, renal, or peripheral vascular territories at presentation or during initial hospitalization. Postoperative outcomes were defined as deficits not present before the intervention. Outcomes were compared between the groups by use of Kaplan-Meier and descriptive statistics. We treated 442 patients with ATBAD. Of those 442, 60.6% had uATBAD and were treated medically, and 39.4% had cATBAD, of whom 39.0% were treated medically to 30.0% with open repair, 21.3% with thoracic endovascular aortic repair, and 9.7% with other open peripheral procedures. Intervention-free survival at 1 and 5 years was 84.8% and 62.7% for uATBAD, 61.8% and 44.0% for cATBAD-medical, 69.2% and 47.2% for cATBAD-open, and 68.0% and 42.5% for cATBAD–thoracic endovascular aortic repair, respectively (P=0.001). Overall survival was significantly related primarily to complicated presentation.

Conclusions—

In our experience, early and late outcomes of ATBAD were dependent on the presence of complications, with cATBAD faring worse. Although uATBAD was associated with favorable early survival, late complications still occurred, mandating radiographic surveillance and open or endovascular interventions. Prospective trials are required to better determine the optimal therapy for uATBAD.