Acute Type B Aortic Dissection Research Articles

Effect of Thoracic Endovascular Aortic Repair on Aortic Remodeling in Patients with Type B Aortic Dissection in an Asian Population

Management of uncomplicated type B aortic dissection (TBAD) has traditionally been aggressive medical therapy. Recent studies brought about a paradigm shift with evidence to suggest benefits from early endovascular intervention to a high risk subgroup of acute uncomplicated TBAD patients. We aim to review the effects of aortic remodeling in Asian patients with TBAD with and without endovascular intervention, including maximal aortic diameter, true lumen diameter, and false lumen thrombosis. This is a single-center retrospective study of a prospective database. Patients who presented to our institution with acute TBAD from January 2008 to December 2015 (n=44) were evaluated. Eighteen percent (8 patients) presented with complicated TBAD and underwent emergency thoracic endovascular aortic repair (TEVAR) while the remaining 82% (36 patients) were treated with optimal medical therapy (OMT). Six patients under the conservative arm crossed over to elective TEVAR after 6weeks because of interval radiological progression of disease. There was no significant difference in the baseline demographics of the TEVAR group and the OMT group. At 24 months, mean maximal aortic diameter difference was -7.7mm and +1.9mm (P=0.077), mean true lumen diameter difference was +10.0mm and +2.6mm (P=0.049), and false lumen thrombosis was 100% and 20% (P=0.012) for TEVAR and OMT, respectively. Kaplan-Meier analysis showed no significant difference in mortality between the 2 groups at 30 days and 2 years. Within an Asian population with TBAD, TEVAR with OMT has a significant positive effect on aortic remodeling, compared with OMT-only management.

Cause-specific mortality of type B aortic dissection and assessment of competing risks of mortality

ObjectiveNatural history studies of type B aortic dissection (TBAD) commonly report all-cause mortality. Our aim was to determine cause-specific mortality in TBAD and to evaluate the clinical characteristics associated with aorta-related and nonaorta-related mortality. MethodsClinical and administrative records were reviewed for patients with acute TBAD between 1995 and 2017. Demographics, comorbidities, presentation, and initial imaging findings were abstracted. Cause of death was ascertained through a multimodality approach using electronic health records, obituaries, social media, Social Security Death Index, and state mortality records. Causes of death were classified as aorta related, nonaorta related, or unknown. A Fine-Gray multivariate competing risk regression model for subdistribution hazard ratio was employed to analyze the association of clinical characteristics with aorta-related and nonaorta-related mortality. ResultsA total of 275 individuals met inclusion criteria (61.1 ± 13.7 years, 70.9% male, 68% white). Mean survival after discharge was 6.3 ± 4.7 years. Completeness of follow-up Clark C index was 0.87. All-cause mortality was 50.2% (n = 138; mean age, 70.1 ± 14.6 years) including an in-hospital mortality of 8.4%. Cause-specific mortality was aorta related, nonaorta related, and unknown in 51%, 43%, and 6%, respectively. Compared with patients with nonaorta-related mortality, patients with aorta-related mortality were younger at acute TBAD (69.5 ± 11.2 years vs 61.6 ± 15.5 years; P = .001), underwent more descending thoracic aortic repairs (19.4% vs 45.8%; P = .002), and had a shorter survival duration (5.7 ± 3.9 vs 3.4 ± 4.5 years; P = .002). There was clear variation in cause of death by each decade of life, with higher aorta-related mortality among those younger than 50 years and older than 70 years and a stepwise increase in nonaorta-related mortality with each increasing decade (P < .001). All-cause mortality at 1 year, 3 years, and 10 years was 15%, 24%, and 57%, respectively. After accounting for competing risks, the cumulative incidence of aorta-related mortality at 1 year, 3 years, and 10 years was 8.9%, 16.5%, and 27.2%, respectively, and that of nonaorta-related mortality was 2.7%, 7.2%, and 29%, respectively. A maximum descending thoracic aortic diameter >4 cm was associated with an increase in hazard of aorta-related mortality by 84% (subdistribution hazard ratio, 1.84; 95% confidence interval, 1.03-3.28) on multivariate competing risk regression analysis. ConclusionsTBAD is associated with high 10-year mortality. Those at risk for aorta-related mortality have a clinical phenotype different from that of individuals at risk for nonaorta-related mortality. This information is important for building risk prediction models that account for competing mortality risks and to direct optimal and individualized surgical and medical management of TBAD.

Altered aortic arch geometry in patients with type B aortic dissection.

This study aims to evaluate differences in proximal aorta geometry and identify specific anatomical predictors of type B aortic dissection (TBAD). We evaluated computed tomographic angiograms of controls (n = 185) and patients with acute TBAD (n = 173). Using propensity score matching, we created 2 groups of 127 patients. 3mensio Vascular software was used to analyse the computed tomographic angiograms and measure the diameter, length, tortuosity index and angulation of the proximal aorta (divided into ascending aorta and aortic arch). Tortuosity index was calculated by dividing the centre lumen line length of the aortic segment by its shortest length. Angulation was measured by the centre lumen line 'tangent line angle'. Two independent multivariable models identified significant anatomical associations regarding the tortuosity and angulation geometry. Aortic diameter and ascending aorta and aortic arch lengths in TBAD increased significantly. The aortic arch tortuosity was significantly higher in the TBAD group (P < 0.001), with no difference regarding the ascending aorta (P = 0.11). Ascending aorta and aortic arch angulation were significantly higher in the TBAD group (P = 0.01, P < 0.001, respectively). Multivariable analyses showed that increased aortic arch tortuosity and angulation were significant predictors of the development of TBAD [odds ratio (OR) 1.91, 95% confidence interval (CI) 1.40-2.59; P < 0.001 and OR 1.08, 95% CI 1.04-1.12; P < 0.001], respectively. In addition to proximal aorta dilation and elongation, we identified increased aortic arch tortuosity and angulation as possible specific predictors of TBAD.

OUTCOMES FOLLOWING ENDOVASCULAR THERAPY IN TYPE B ACUTE AORTIC DISSECTION STRATIFIED BY RISK LEVEL

The International Registry of Acute Aortic Dissection (IRAD) previously showed a longitudinal trend of decreasing in-hospital and 5 year post discharge mortality of Type B acute aortic dissection (TBAAD). However, this decline was not observed among the subgroup of TBAAD receiving endovascular

ENDOVASCULAR MANAGEMENT OF TYPE B ACUTE AORTIC DISSECTION IN NON-SYNDROMIC PATIENTS WITH A FAMILY HISTORY OF AORTIC DISEASE

While a genetic basis for thoracic aortic aneurysm and dissection is well established, little is known about endovascular stent graft therapy (TEVAR) outcomes in patients with family history of aortic disease following Type B acute aortic dissection (TBAD). Patients enrolled in the International

Anticoagulant and anti-thrombotic therapy in acute type B aortic dissection: when real-life scenarios face the shadows of the evidence-based medicine

BackgroundEvidence-based recommendations about anticoagulation in acute type B aortic dissection (TBAD) are completely missing, but there is a diffuse conviction that it could prevent the healing process of the dissected aorta’s false lumen. However, several clinical conditions may lead to the necessity to start anticoagulant therapy among patients with acute type B aortic dissection, ranging from atrial fibrillation to more complicated clinical scenarios and the correct management in this kind of patients is still an open issue.Case presentationWe are presenting a 51-years-old man with multi-infarct encephalopathy referred to us for an acute TBAD and a first diagnosis of ischemic cardiomyopathy complicated by left ventricular (LV) thrombus formation. Coronary angiography revealed a critical stenosis of left anterior descending artery (LAD) treated with drug-eluting stent deployment. The patient was addressed to triple antithrombotic therapy with acetylsalicylic acid, clopidogrel and warfarin with target INR 2.0–2.5. After 6 months, computed tomography angiography revealed the stability of the dissection flap. Cardiac magnetic resonance imaging, however, confirmed the persistence of a small thrombotic formation in LV apex, thus double antithrombotic therapy with warfarin and clopidogrel was instituted. The patient remained asymptomatic during the follow-up period but was advised to suspend his job and physical activities.ConclusionCurrent guidelines do not discuss anticoagulant therapy in the setting of TBAD and large randomized trials are lacking. Despite it is generally considered unsafe to administer anticoagulants in patients with TBAD, we present a case in which triple antithrombotic therapy was well tolerated and did not lead to progression of the intimal flap after 6 months.

Comparison of mid-term outcomes of endovascular repair and medical management in patients with acute uncomplicated type B aortic dissection

ObjectivesTo further assess the early and mid-term outcomes of thoracic endovascular aortic repair (TEVAR) in patients with acute uncomplicated type B aortic dissection (TBAD) compared with those receiving best medical treatment (BMT). MethodsBetween February 2008 and March 2018, 357 consecutive patients with acute uncomplicated TBAD were retrospectively analyzed. Among them, 191 patients underwent TEVAR, and 166 received BMT. After propensity score matching, we obtained 145 matched pairs for analysis. ResultsIn the matched population, the 30-day mortality between the TEVAR group and the BMT group showed no statistically significant difference, whereas the early adverse events rates in the TEVAR group were significantly greater than that of the BMT group (P = .003). Freedom from all-cause mortality in the TEVAR group was significantly greater than that of the BMT group (TEVAR: 91.9% at 5 years, BMT: 82.2% at 5 years, P = .028). Freedom from aortic-related mortality in the TEVAR group was significantly greater than that of the BMT group (TEVAR: 94.1% at 5 years, BMT: 86.1% at 5 years, P = .044). Multivariable Cox-hazard regression analysis demonstrated that the older age (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.01-1.08, P = .013), BMT (HR, 2.33; 95% CI, 1.08-5.05, P = .032), and the distance between the primary entry tear and the left subclavian artery <2.0 cm (HR, 2.30; 95% CI, 1.06-4.99, P = .035) were the significant risk factors for all-cause death. Given death as a competing factor, the cumulative incidence of rupture in the BMT group was significantly greater than that of the TEVAR group (BMT: 13.7% at 5 years, TEVAR: 5.1% at 5 years, P = .024). ConclusionsDespite more complications in the early stage, TEVAR was associated with decreased risk of late death and had fewer late aortic ruptures compared with BMT in patients with acute uncomplicated TBAD. Therefore, TEVAR may be considered as the first option to improve the late outcomes in these patients.

Outcomes of Patients with Acute Type B Aortic Dissection – A 15-Years, Single-Center Experience

Introduction - Over the last two decades, the management of acute type B aortic dissection (ABAD) considerably evolved due to the progress of endovascular techniques. However outcome of type B aortic dissection remains poorly predictable with a high rate of late intervention and/or reintervention. The aim of the study was to assess outcomes of patients treated for ABAD in our center over a 15-years period.

Three Cases of Complicated Acute Type B Aortic Dissection with Intestinal Ischemia

Introduction - Intestinal ischemia with acute type B aortic dissection (ATBAD) is fatal complication. These patients have poor prognosis and require surgical treatment 1). Though, strategies of surgical treatment for these patients remain controversial 2). We experienced three different clinical courses from different strategies for patients with intestinal ischemia in 2016.

Renal Malperfusion Syndrome in Acute Aortic Dissection Type B

Introduction - The treatment of patients with acute type B aortic dissection (ATBAD) combined with malperfusion syndrome is challenging. The aim of our study was to analyse frequency of renal malperfusion (RMP) among patients with ATBAD, and its impact on management and outcome of the patients.

Factors Predicting Aneurysmal Degeneration of Medically Managed Type B Aortic Dissections

Introduction: Aneurysmal degeneration of medically managed type B aortic dissection (TBAD) can be a life-threatening condition. Preventive thoracic endovascular aorta repair (TEVAR) in patients at risk could potentially be beneficial. A number of predictive factors for aneurysmal degeneration of medically managed type B aortic dissections have already been described in literature. However, no study yet has revised these risk factors coupled to the aortic dissection risk tool (Stanford Aortic Dissection Risk Calculator) developed by Sailer et al 1 The objectives of this study is to examine the predictors for late aneurysmal dilatation after TBAD. Methods: A retrospective study was conducted on 100 patients initially treated medically for acute TBAD. Relevant demographic, biochemical and radiographic variables at presentation were studied. The aortic dissection risk calculator tool developed by Sailer et al.1, predicting the risk of adverse events after aortic dissection based on demographic and radiographic variables at presentation, was tested retrospectively. Results: With a median follow-up of 36 months (range 13-76), 43 patients underwent surgery (72.1% TEVAR). A larger initial aortic and false lumen diameter as well as a greater distal extension of the dissection was associated with higher need for surgery (respectively, p=0.004, p=0.020 and p=0.003). A more specific predictor for TEVAR was an initial aortic diameter above 40mm (p=0.024). Higher growth rates of the maximum aortic diameter were observed with a greater distal extension of the dissection, larger false lumen diameters and false lumen outflow, and entry tears located at the inner aortic arch (respectively, p=0.002, p=0.011, p=0.046 and p=0.027). No significant correlations were found for the absolute and relative risks provided by the calculator tool. Conclusion: The initial maximum aortic diameter of the aortic dissection is a key predictor for aortic growth. Furthermore, the distal extension of the aortic dissection also seems to play an important role in late aneurysmal degeneration. However, we were not able to confirm the added value of the risk calculator tool in general practice. A prospective study is needed with more uniform data collection and follow-up imaging. Disclosure: Nothing to disclose

Surgical Outcomes And Postoperative Descending Aorta Morphologic Remodeling After Thoracic Endovascular Aortic Repair For Acute And Chronic Type B Aortic Dissection.

BackgroundThis study aims to investigate the descending aortic morphological alterations caused by pathological changes in acute and chronic Type B aortic dissection (TBAD) and morphological remodeling after thoracic endovascular aortic repair (TEVAR).Patients and methodsFrom February 2012 to January 2016, 86 TBAD patients undergoing TEVAR were divided into an acute group (n=63) and a chronic group (n=23). The areas of the true, false and maximal lumen and descending aorta morphological parameters, including the taper ratio (TR), oversizing ratio (OR), mismatch ratio (MR), radius of curvature (RoC) and tortuosity index (TI), were evaluated. Follow-ups were performed postoperatively before discharge, at 1 and 6 months, and yearly thereafter.ResultsBefore TEVAR, the TR (0.57 (0.49) vs 0.74 (0.60); P < 0.05), OR (2.75 ± 1.89 vs 3.96 ± 2.27; P < 0.05) and TI (1.22 (1.19) vs 1.41 ± 0.17; P < 0.05) were significantly higher in the chronic group than in the acute group. The TEVAR technical success rate was 100%. No differences were found in 30-day and >30-day mortality between the two groups. Pathology-specific devices, such as tapered stent grafts and distal bare stents, were used more frequently in the chronic group than in the acute group (47.8% vs 23.8%, P = 0.03; 43.5% vs 12.7%, P = 0.002, respectively). The OR and TI changes that occurred after TEVAR were significantly higher in the chronic group than in the acute group (1.80 ± 0.86 vs 2.98 ± 1.85, P = 0.028; 0.00 ± 0.09 vs 0.09 ± 0.10, P < 0.001, respectively).ConclusionTEVAR is a safe and effective therapy for acute and chronic TBAD. Compared to acute TBAD, chronic TBAD resulted in an adverse preoperative descending aorta morphology. Pathology-specific devices may be a feasible treatment option for endovascular repair of chronic TBAD. A larger series of cases with longer follow-up are needed to draw definitive conclusions.

Dissection Level Within Aortic Wall Layers is Associated with Propagation of Type B Aortic Dissection: A Swine Model Study

Haemodynamic and geometric factors play pivotal roles in the propagation of acute typeB aortic dissection (TBAD). The aim of this study was to evaluate the association between dissection level within all aortic layers and the propagation of acute TBAD in porcine aorta. In twelve pigs, two models of TBAD were created. In model A (n = 6), the aortic wall tear was superficial and close to the intima (thin intimal flap), whereas in model B (n = 6) it was deep and close to the adventitia (thick intimal flap). Dissection propagation was evaluated using angiography or computed tomography scans, and the haemodynamic measurements were acquired using Doppler wires. Most pigs were followed up at 1, 3, 6, 12, 18, and up to 24 months; four animals were euthanised at three and six months, respectively (two from each group). Both models were successfully created. No statistical difference was observed for the median antegrade propagation distance intra-operatively between the two models (p=.092). At 24 months, the longitudinal propagation distance was significantly greater in model B than in model A (p=.016). No statistical difference in retrograde propagation was noted (p=.691). Over time, aortic wall dissection progressed most notably over the first three months in model A, whereas it continued over the first 12 months in model B. Flow velocity was significantly greater in the true lumen than in false lumen at the level of the primary tear (p=.001) and in the middle of the dissection (p=.004). The histopathological images at three and six months demonstrated the fibres were stretched linearly at the outside wall of false lumen in both models, while the depth of intimal tears developed to be superficial and similar at the distal dissection. In this swine model of TBAD, a deeper intimal tear resulted in greater dissection propagation.

Thoracic Endovascular Aortic Repair on Zone 2 Landing for Type B Aortic Dissection

Although thoracic endovascular aortic repair (TEVAR) is an effective treatment for both complicated and uncomplicated type B aortic dissection (TBAD), the occurrence of retrograde type A aortic dissection (RTAD) after TEVAR could be a disastrous complication. The aim of this study was to examine the safety of zone 2 TEVAR in the treatment of acute and subacute TBAD. A Relay stent graft (SG) was placed proximally beyond the left subclavian artery (LSA) as zone 2 TEVAR for complicated or uncomplicated TBAD. LSA was preserved by physician-modified fenestrated TEVAR (F-TEVAR) if anatomically possible or by surgical reconstruction of debranching TEVAR (D-TEVAR) if necessary. Otherwise, LSA was simply covered. Changes in the aortic diameters after TEVAR were evaluated using CT scanning. Between 2013 and 2017, 22 patients (mean age: 63±14years; 16 males) with TBAD were treated with zone 2 TEVAR. Emergency TEVAR was performed in 9 patients (41%) for complicated TBAD, and elective TEVAR was performed in 13 patients (59%) for uncomplicated TBAD in subacute phases. LSA was preserved in 16 patients via 15 F-TEVAR and 1 D-TEVAR and intentionally covered in 6 patients on emergency TEVAR. Elective TEVAR succeeded in the preservation of LSA flow in all patients (emergency 33% vs. elective 100%; P<0.01). There were no TEVAR-related complications such as stroke, spinal cord ischemia, and RTAD. Thirty-day mortality was 0%. Aortic remodeling as the expansion of true lumen and shrinkage and complete thrombosed occlusion of false lumen were prominent at the level of SG placement 12months after TEVAR. During the follow-up period, stent-induced new entry at the distal edge of the SG occurred in 1 patient (4%); however, there was no case of aorta-related mortality. Zone 2 TEVAR for acute and subacute TBAD might be promising for the prevention of RTAD.

Preoperative proteinuria and clinical outcomes in type B aortic dissection after thoracic endovascular aortic repair.

Background Proteinuria is a marker of poor outcomes in several diseases; however, few studies have been conducted to explore the prognostic value of proteinuria, assessed by urine dipstick test, for clinical outcomes in patients with type B acute aortic dissection (TBAD) undergoing thoracic endovascular aortic repair (TEVAR). Methods Consecutive patients with TBAD undergoing TEVAR were enrolled from January 2010 to July 2015. Proteinuria was defined as trace or higher, according to the results of urine dipstick testing. Associations among proteinuria and adverse events were evaluated. Results In total, 671 patients with a mean age of 44±15 years were included in the analysis. Proteinuria was detected in 281 patients (41.9%) before TEVAR. Multivariate logistic regression analysis showed that C-reactive protein and impaired renal function were independent predictors for proteinuria. During hospitalization, 21 patients died. In-hospital mortality was higher in patients with proteinuria (1.5% vs. 5.3%, p=0.005). After a median 3.4 years follow up, the post-TEVAR death rate was 10.4% (85 patients were lost to follow-up). The long-term cumulative mortality was significantly higher in patients with proteinuria (17.2% vs. 8.2%, log-rank=11.36, p=0.001). Multivariate Cox survival modeling indicated that proteinuria was significantly associated with long-term death, after adjustment for potential confounding risk factors (HR=1.92, p=0.012). Conclusions Pre-TEVAR proteinuria was identified as a prognostic marker in patients with TBAD and has potential for application as a convenient and simple risk assessment method before TEVAR.

The natural history of type B aortic dissection in patients with PRKG1 mutation c.530G>A (p.Arg177Gln)

ObjectiveThe c.530G>A (p.Arg177Gln) mutation in PRKG1 has been shown to be associated with thoracic aortic aneurysms and dissections. This rare mutation accounts for an estimated 1% of nonsyndromic heritable thoracic aortic disease. We sought to describe the clinical presentation of type B aortic dissection (TBAD), management, and outcomes in patients with this mutation. MethodsThis is a descriptive multi-institutional retrospective study of patients from six families with the PRKG1 mutation. Patients with TBAD were selected for analysis. Demographics, family histories, TBAD management, and outcomes were reviewed. ResultsOf the 29 individuals diagnosed with the PRKG1 mutation, 12 (41.3%) had TBAD (50% male, TBAD median age: 31 years [range, 16-58 years], median follow-up: 6 years [range, 3-15 years] after TBAD). All had a family history of aortic dissections and none had features of Marfan syndrome. The median size of the descending thoracic aorta (DTA) at TBAD was 4.1 cm (range, 3.8-5 cm). Most cases (9 acute TBAD, 1 incidental TBAD diagnosis during screening) were managed medically. One case had open DTA repair the acute phase. Repair for dissection-related aneurysmal degeneration was performed in seven cases (58.3%) in the chronic phase at a median of 2 years (range, 1-8 years) after TBAD. In four cases (33.3%), the DTA remained stable in size over a range of 1 to 7 years after TBAD. Type A aortic dissection subsequent to TBAD occurred in three cases (25%). There were four (33.3%) deaths in the series, all aortic related at a median age of 24 years (range, 19-43 years). ConclusionsThe PRKG1 (p.Arg177Gln) mutation although rare is associated with nonsyndromic TBAD in young and middle-aged patients. Workup for this gene mutation should be included as part of the workup for TBAD etiology in relatively young patients and those with familial history of aortic dissections. Once diagnosed, testing of first-degree family members is warranted. In all individuals with a PRKG1 mutation, close follow-up for aortic root dilatation and hypertension control is essential to reduce the risk of type A or type B aortic dissection, and in cases of TBAD, to decrease the risk of dissection-related aneurysmal degeneration.

3067 Biomechanical analysis of acute versus chronic aortic dissection flaps

OBJECTIVES/SPECIFIC AIMS: Thoracic endovascular aortic repair (TEVAR) is more effective in remodeling the dissected aorta in acute versus chronic type B aortic dissection (TBAD). It has been hypothesized that this is due to differences in dissection flap biomechanical and structural properties but has not been confirmed in explanted human aortic tissue. We aimed to characterize and compare differences in tissue biomechanics and microstructure between acute and chronic dissection flaps that may underlie these findings. METHODS/STUDY POPULATION: Dissection flaps were obtained at time of operative repair for patients presenting for open aortic replacement to treat acute type A (ACUTE, n=7) or chronic type B (CHRONIC, n=7) aortic dissection. Given that the current treatment modality for acute complicated TBAD is TEVAR, it was not feasible to acquire acute TBAD flaps for analysis. Tissues were cryopreserved and subjected to biaxial tensile testing in the circumferential and longitudinal directions. Stiffness was quantified by the tangent modulus (TM) in the low and high linear regions of the compiled equibiaxial response curves for each cohort. Extensibility was defined as the intersection of the fitted line from the high linear region with the x-axis, and the degree of anisotropy (DA) was defined as the mean absolute percentage error of the strains in both directions. Flap architecture and collagen fiber organization were also compared between groups using two-photon microscopy. RESULTS/ANTICIPATED RESULTS: Average age of dissection flaps were 3.4±3.4 days in ACUTE and 1,868.7±1,354.0 days in CHRONIC (p=0.011). There were no differences in age, co-morbidities, maximum aortic diameter, and aortic wall thickness. ACUTE exhibited an anisotropic stress-strain response with increased extensibility longitudinally than circumferentially (0.18 vs. 0.09, p=0.022, DA=0.67) while CHRONIC demonstrated an isotropic response with similar extensibility in either direction (0.11 vs. 0.12, p=0.606, DA=0.26). CHRONIC and ACUTE had comparable stiffness in the circumferential direction (TMlow 439.92 vs. 541.08, p=0.729, and TMhigh 1585.19 kPa vs. 1869.35 kPa, p=0.817). In the longitudinal direction, CHRONIC was significantly stiffer than ACUTE (TMhigh 8347.61 kPa vs. 1201.34 kPa, p=0.049) (FIGURE). Microscopy corroborated these findings with greater collagen fiber organization circumferentially than longitudinally in ACUTE and increasing fibrosis, collagen predominance, and straightening of collagen fibers in CHRONIC. DISCUSSION/SIGNIFICANCE OF IMPACT: Compared to ACUTE, CHRONIC exhibited loss of anisotropy with increased tissue stiffness in the longitudinal direction. Increased dissection flap fibrosis and decreased compliance may explain the worse outcomes for aortic remodeling after TEVAR in chronic TBAD. This study offers biomechanical support for early TEVAR in the acute phase of uncomplicated TBAD.

Impact of the Intima Dynamic Motion in Type B Acute Aortic Dissection on Renal Injury: Quantificationally Assessed by Dose-Regulated Retrospective ECG-Gated Dual-Source CT Angiography

Little is known about the influence of intima dynamic motion on organ ischemia and related outcomes. The purpose of this study is to quantitatively evaluate intima oscillation by CT angiography (CTA), determine its impact on acute kidney injury (AKI) in patients with type B acute aortic dissection (TB-AAD) before thoracic endovascular aortic repair (TEVAR), and further analyze its association with early adverse events postoperatively. Totally, 108 patients with TB-AAD who underwent retrospective ECG-gated CTA and received TEVAR were enrolled. Patients were divided into AKI and non-AKI groups. Area of the true lumen (TLA) was computed at R-R intervals at the upper level of kidney vessel origin every 5% step from 0% to 95%. Additionally, other morphologic parameters that have been identified as risk predictors for adverse events in uncomplicated TB-AAD were evaluated. Forty-three (39.8%) patients were sorted into the AKI group. Patients with AKI exhibited a larger value for the relative change of TLA (Crel-TLA) than patients in the non-AKI group (p < 0.001), as well as a larger maximum diameter of the descending aorta (p = 0.023) and the primary entry tear (p = 0.012). Crel-TLA and elevated systolic blood pressure were independent predictors of AKI. Patients with Crel-TLA ≥ 42.6% were associated with a high incidence of renal ischemia before TEVAR and early adverse events postoperatively (all p < 0.001). Intima dynamic motion, as quantitatively evaluated by CTA, has a significant influence on renal injury before and after the aortic intervention, as well as other adverse events, which might guide clinical therapy in high-risk patients.

The Impact of the Morphologic Characteristics of Type B Aortic Dissection in the Acute Phase on the Aortic Enlargement in the Late Stage

Objectives: According to the International Registry of Acute Aortic Dissection, >70% of patients with type-B aortic dissection (AD) have delayed aortic growth. The objective of this study was to investigate the morphologic characteristics of aortic enlargement in type-B AD. Methods: A total of 120 patients with uncomplicated acute type-B aortic dissection (uATBAD) were divided into 4 groups according to the presence of a patent or thrombosed false lumen (FL) with or without aortic enlargement. In all groups, the area of the true lumen (TL) and the FL were measured on axial computed tomography images. Results: A total of 120 uATBAD patients were evaluated: patent FL with (PE, N = 28, 23%) or without aortic enlargement (PU, N = 17, 14%) and thrombosed FL with (TE, N = 34, 28%) or without enlargement (TU, N = 41, 34%). The initial aortic diameter was not significantly different among the 4 groups (PE vs. PU = 39 ± 8 vs. 37 ± 10 (p = 0.354); TE vs. TU = 38 ± 6 vs. 37 ± 6 (p = 0.391)). The area of the FL tended to be larger in the PE group. In contrast, the area of the TL was significantly larger in the TE group. Late outcomes of uATBAD treated with optimal medical treatment were acceptable. Conclusions: In patients with uATBAD and a thrombosed FL, the patients with aortic enlargement tended to be increased TL size. In contrast, in patients with a patent FL, the patients with aortic enlargement tended to be increased FL size.

Implications of secondary aortic intervention after thoracic endovascular aortic repair for acute and chronic type B dissection

BackgroundThoracic endovascular aortic repair (TEVAR) has become a mainstay of therapy for acute and chronic type B aortic dissection (TBAD). Dynamic aortic morphologic changes, untreated dissected aorta, and persistent false lumen perfusion have significant consequences for reintervention after TEVAR for TBAD. However, few reports contrast differences in secondary aortic intervention (SAI) after TEVAR for TBAD or describe their influence on mortality. This analysis examined incidence, timing, and types of SAI after TEVAR for acute and chronic TBAD and determined their impact on survival. MethodsAll TEVAR procedures for acute and chronic TBAD (2005-2016) were retrospectively reviewed. Patients with staged (<30 days) or concomitant ascending aortic arch repair or replacement were excluded. Acuity was defined by symptom onset (0-30 days, acute; >30 days, chronic). SAI procedures were grouped into open (intended treatment zone or remote aortic site), major endovascular (TEVAR extension or endograft implanted at noncontiguous site), and minor endovascular (side branch or false lumen embolization) categories. Kaplan-Meier methodology was used to estimate freedom from SAI and survival. Cox proportional hazards were used to identify SAI predictors. ResultsTEVAR for TBAD was performed in 258 patients (acute, 49% [n = 128]; chronic, 51% [n = 130]). Mean follow-up was 17 ± 22 months with an overall SAI rate of 27% (n = 70; acute, 22% [28]; chronic, 32% [42]; odds ratio, 1.7; 95% confidence interval, 0.9-2.9; P = .07]. Median time to SAI was significantly less after acute than after chronic dissection (0.7 [0-12] vs 7 [0-91] months; P < .001); however, freedom from SAI was not different (1-year: acute, 67% ± 4%, vs chronic, 68% ± 5%; 3-year: acute, 65% ± 7%, vs chronic, 52% ± 8%; P = .7). Types of SAI were similar (acute vs chronic: open, 61% vs 55% [P = .6]; major endovascular, 36% vs 38% [P = .8]; minor endovascular, 21% vs 21% [P = 1]). The open conversion rate (either partial or total endograft explantation: acute, 10% [13/128]; chronic, 15% [20/130]; P = .2) and incidence of retrograde dissection (acute, 6% [7/128]; chronic, 4% [5/130]; P = .5) were similar. There was no difference in survival for SAI patients (5-year: acute + SAI, 55% ± 9%, vs acute without SAI, 67% ± 8% [P = .3]; 5-year: chronic + SAI, 72% ± 6%, vs chronic without SAI, 72% ± 7% [P = .7]). Factors associated with SAI included younger age, acute dissection with larger maximal aortic diameter at presentation, Marfan syndrome, and use of arch vessel adjunctive procedures with the index TEVAR. Indication for the index TEVAR (aneurysm, malperfusion, rupture, and pain or hypertension) or remote preoperative history of proximal arch procedure was not predictive of SAI. ConclusionsSAI after TEVAR for TBAD is common. Acute TBAD has a higher proportion of early SAI; however, chronic TBAD appears to have ongoing risk of remediation after the first postoperative year. SAI types are similar between groups, and the occurrence of aorta-related reintervention does not affect survival. Patients' features and anatomy predict need for SAI. These data should be taken into consideration for selection of patients, device design, and surveillance strategies after TEVAR for TBAD.