Initial Thoracic Endovascular Aortic Repair vs Medical Therapy for Acute Uncomplicated Type B Aortic Dissection

Importance

Thoracic endovascular aortic repair (TEVAR) has increasingly been used for uncomplicated type B aortic dissection (uTBAD) despite limited supporting data.

Objective

To assess whether initial TEVAR following uTBAD is associated with reduced mortality or morbidity compared with medical therapy alone.

Design, Setting, and Participants

This cohort study included Centers for Medicare & Medicaid Services inpatient claims data for adults aged 65 years or older with index admissions for acute uTBAD from January 1, 2011, to December 31, 2018, with follow-up available through December 31, 2019.

Exposures

Initial TEVAR was defined as TEVAR within 30 days of admission for acute uTBAD.

Main Outcomes and Measures

Outcomes included all-cause mortality, cardiovascular hospitalizations, aorta-related and repeated aorta-related hospitalizations, and aortic interventions associated with initial TEVAR vs medical therapy. Propensity score inverse probability weighting was used.

Results

Of 7105 patients with eligible index admissions for acute uTBAD, 1140 (16.0%) underwent initial TEVAR (623 [54.6%] female; median age, 74 years [IQR, 68-80 years]) and 5965 (84.0%) did not undergo TEVAR (3344 [56.1%] female; median age, 76 years [IQR, 69-83 years]). Receipt of TEVAR was associated with region (vs South; Midwest: adjusted odds ratio [aOR], 0.66 [95% CI, 0.53-0.81]; P < .001; Northeast: aOR, 0.63 [95% CI, 0.50-0.79]; P < .001), Medicaid dual eligibility (aOR, 0.76; 95% CI, 0.63-0.91; P = .003), hypertension (aOR, 1.26; 95% CI, 1.03-1.54; P = .03), peripheral vascular disease (aOR, 1.24; 95% CI, 1.02-1.49; P = .03), and year of admission (2012, 2013, 2014, and 2015 were associated with greater odds of TEVAR compared with 2011). After inverse probability weighting, mortality was similar for the 2 strategies up to 5 years (hazard ratio [HR], 0.95; 95% CI, 0.85-1.06), as were aorta-related hospitalizations (HR, 1.12; 95% CI, 0.99-1.27), aortic interventions (HR, 1.01; 95% CI, 0.84-1.20), and cardiovascular hospitalizations (HR, 1.05; 95% CI, 0.93-1.20). In a sensitivity analysis that included deaths within the first 30 days, initial TEVAR was associated with lower mortality over a period of 1 year (adjusted HR [aHR], 0.86; 95% CI, 0.75-0.99; P = .03), 2 years (aHR, 0.85; 95% CI, 0.75-0.96; P = .008), and 5 years (aHR, 0.87; 95% CI, 0.80-0.96; P = .004).

Conclusions and Relevance

In this study, 16.0% of patients underwent initial TEVAR within 30 days of uTBAD, and receipt of initial TEVAR was associated with hypertension, peripheral vascular disease, region, Medicaid dual eligibility, and year of admission. Initial TEVAR was not associated with improved mortality or reduced hospitalizations or aortic interventions over a period of 5 years, but in a sensitivity analysis that included deaths within the first 30 days, initial TEVAR was associated with lower mortality. These findings, along with cost-effectiveness and quality of life, should be assessed in a prospective trial in the US population.

Wall stress analyses in patients with ≥5 cm versus <5 cm ascending thoracic aortic aneurysm

OBJECTIVE

Current guidelines for elective surgery of ascending thoracic aortic aneurysms (aTAAs) use aneurysm size as primary determinant for risk stratification of adverse events. Biomechanically, dissection may occur when wall stress exceeds wall strength. Determining patient-specific aTAA wall stresses by finite element analysis can potentially predict patient-specific risk of dissection. This study compared peak wall stresses in patients with ≥5.0 cm versus <5.0 cm aTAAs to determine correlation between diameter and wall stress.

METHODS

Patients with aTAA ≥5.0 cm (n = 47) and <5.0 cm (n = 53) were studied. Patient-specific aneurysm geometries obtained from echocardiogram-gated computed tomography were meshed and prestress geometries determined. Peak wall stresses and stress distributions were determined using LS-DYNA finite element analysis software (LSTC Inc, Livermore, Calif), with user-defined fiber-embedded material models under systolic pressure.

RESULTS

Peak circumferential stresses at systolic pressure were 530 ± 83 kPa for aTAA ≥5.0 cm versus 486 ± 87 kPa for aTAA <5.0 cm (P = .07), whereas peak longitudinal stresses were 331 ± 57 kPa versus 310 ± 54 kPa (P = .08), respectively. For aTAA ≥5.0 cm, correlation between peak circumferential stresses and size was 0.41, whereas correlation between peak longitudinal wall stresses and size was 0.33. However, for aTAA <5.0 cm, correlation between peak circumferential stresses and size was 0.23, whereas correlation between peak longitudinal stresses and size was 0.14.

CONCLUSIONS

Peak patient-specific aTAA wall stresses overall were larger for ≥5.0 cm than aTAA <5.0 cm. Although some correlation between size and peak wall stresses was found in aTAA ≥5.0 cm, poor correlation existed between size and peak wall stresses in aTAA <5.0 cm. Patient-specific wall stresses are particularly important in determining patient-specific risk of dissection for aTAA <5.0 cm.

Inflammasomes in the Pathophysiology of Aortic Disease

Aortic diseases comprise aneurysms, dissections, and several other pathologies. In general, aging is associated with a slow but progressive dilation of the aorta, along with increased stiffness and pulse pressure. The progression of aortic disease is characterized by subclinical development or acute presentation. Recent evidence suggests that inflammation participates causally in different clinical manifestations of aortic diseases. As of yet, diagnostic imaging and surveillance is mainly based on ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI). Little medical therapy is available so far to prevent or treat the majority of aortic diseases. Endovascular therapy by the introduction of covered stentgrafts provides the main treatment option, although open surgery and implantation of synthetic grafts remain necessary in many situations. Because of the risks associated with surgery, there is a need for identification of pharmaceutical targets interfering with the pathophysiology of aortic remodeling. The participation of innate immunity and inflammasome activation in different cell types is common in aortic diseases. This review will thus focus on inflammasome activities in vascular cells of different chronic and acute aortic diseases and discuss their role in development and progression. We will also identify research gaps and suggest promising therapeutic targets, which may be used for future medical interventions.

Anticoagulation and Antiplatelet Medications Do Not Affect Aortic Remodeling after Thoracic Endovascular Aortic Repair for Type B Aortic Dissection

OBJECTIVE

There is a lack of evidence regarding the effect of anticoagulation and antiplatelet medications on aortic remodeling for aortic dissection after endovascular repair. We investigated whether anticoagulation and antiplatelet medications affect aortic remodeling after thoracic endovascular aortic repair (TEVAR) for Type B aortic dissection (TBAD).

METHODS

Records of the Vascular Quality Initiative TEVAR registry (2012-2020) were reviewed. Procedures performed for TBAD were included. Aortic reintervention, false lumen thrombosis of the treated aorta and all-cause mortality at follow-up were compared between patients treated with and without anticoagulation medications. A secondary analysis was performed to assess the effect of antiplatelet therapy in patients not on anticoagulation. Cox proportional hazards models were used to estimate the effect of anticoagulation and antiplatelet therapies on outcomes.

RESULTS

1,210 patients (mean age, 60.7±12.2 years; 825 (68%) males) were identified with a mean follow-up of 21.2±15.7 months (range 1-94 months). 166 (14%) patients were on anticoagulation medications at discharge and at follow-up. Patients on anticoagulation were more likely to be older (mean age, 65.5 vs 60 years; P<.001) and Caucasian (69% vs 55%; P=.003), with higher proportions of coronary artery disease (10% vs 3%; P<.001), congestive heart failure (10% vs 2%; P<.001) and chronic obstructive pulmonary disease (15% vs 9%; P=.017). There were no differences in the mean preoperative thoracic aortic diameter or the number of endografts used. At 18-month, the rates of aortic reinterventions (8% vs 9% log-rank P=.873), complete false lumen thrombosis (52% vs 45%; P=.175) and mortality (2.5% vs 2.7%; P=.209) were similar in patients with and without anticoagulation, respectively. Controlling for covariates with the Cox regression method, anticoagulation use was not independently associated with a decreased rates of complete false lumen thrombosis (hazard ratio (HR) 0.74; 95% confidence interval (CI), 0.5-1.1; P=.132), increased need for aortic reinterventions (HR 1.02; 95% CI, 0.62-1.68; P=.934), and mortality (HR 1.25; 95% CI, 0.64-2.47; P=.514). On a secondary analysis, antiplatelet medications did not affect the rates of aortic reintervention, complete false lumen thrombosis and mortality.

CONCLUSIONS

Anticoagulation and antiplatelet medications do not appear to negatively influence the midterm endpoints of aortic reintervention or death in patients undergoing TEVAR for TBAD. Moreover, it did not impair complete false lumen thrombosis. Anticoagulation and antiplatelet medications do not adversely affect aortic remodeling and survival in this population at midterm.

Association of hemodynamic factors and progressive aortic dilatation following type A aortic dissection surgical repair

Type A aortic dissection (TAAD) involves the ascending aorta or the arch. Acute TAAD usually requires urgent replacement of the ascending aorta. However, a subset of these patients develops aortic rupture due to further dilatation of the residual dissected aorta. There is currently no reliable means to predict the risk of dilatation following TAAD repair. In this study, we performed a comprehensive morphological and hemodynamic analysis for patients with and without progressive aortic dilatation following surgical replacement of the ascending aorta. Patient-specific models of repaired TAAD were reconstructed from post-surgery computed tomography images for detailed computational fluid dynamic analysis. Geometric and hemodynamic parameters were evaluated and compared between patients with stable aortic diameters (N = 9) and those with aortic dilatation (N = 8). Our results showed that the number of re-entry tears and true/false lumen pressure difference were significantly different between the two groups. Patients with progressive aortic dilatation had higher luminal pressure difference (6.7 [4.6, 10.9] vs. 0.9 [0.5, 2.3] mmHg; P = 0.001) and fewer re-entry tears (1.5 [1, 2.8] vs. 5 [3.3, 7.5]; P = 0.02) compared to patients with stable aortic diameters, suggesting that these factors may serve as potential predictors of aneurysmal dilatation following surgical repair of TAAD.

Authentication of In Situ Measurements for Thoracic Aortic Aneurysms in Mice

[Figure: see text].

Aortic Neck Dilatation Following Thoracic Endovascular Aortic Repair

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has become a mainstay of treatment for a variety of thoracic aortic pathologies. Expansion of the proximal aortic neck after endovascular repair of abdominal aortic aneurysms has been demonstrated; however, dilatation of the proximal aortic neck after TEVAR has not been well described. We sought to describe remodeling of the proximal neck following TEVAR.

METHODS

This is a retrospective, single institution review of patients who underwent TEVAR for thoracic aortic aneurysm (TAA) and dissection with aneurysmal degeneration from 2010 to 2019. Postoperative computed tomography scans were reviewed and aortic diameter was measured in orthogonal planes using 3-dimensional centerline reconstruction software. The primary outcome was change in aortic diameter at the proximal aortic neck as compared to the initial postoperative computed tomography scan. Clinical and operative data were analyzed to identify factors associated with significant neck dilatation.

RESULTS

Of 87 patients who underwent TEVAR during the study period, 30 met inclusion criteria. Median follow up was 20.5 months. Median age was 67 years, and 15 patients (50%) were female. The proximal aortic neck experienced an overall increase over time in aortic diameter. Five mm distal to the graft showed the greatest rate of expansion, with a median increase of 1.3, 2.9, and 6.2 mm at one year, two years, and three years, respectively. When comparing patients who had mean expansion at this location of >2.0 mm/year to patients who did not, a higher percentage had dissection pathology (81.8% vs. 31.6%, P = 0.008), had graft placement at aortic landing zone 2 (36.4% vs. 5.3%, P = 0.028), and were smokers (100% vs. 52.6%, P = 0.006). Higher percent oversizing was shown to be associated with significant aortic neck dilatation for true aneurysms only.

CONCLUSIONS

Aortic neck dilatation occurs over time for the majority of patients following TEVAR with the distal neck experiencing the highest rate of expansion. Dissection pathology, aortic landing zone 2, and smoking were found to be associated with a higher rate of neck dilatation.

Evaluation of the Gore TAG thoracic branch endoprosthesis in the treatment of proximal descending thoracic aortic aneurysms

BACKGROUND

Thoracic endovascular aortic repair has radically transformed the treatment of descending thoracic aortic aneurysms. However, when aneurysms involve the aortic arch in the region of the left subclavian artery, branch vessel preservation must be considered. Branched aortic endografts have provided a new option to maintain branch patency.

METHODS

Six investigative sites enrolled 31 patients in a nonrandomized, prospective investigational device exemption feasibility trial of a single branched aortic endograft for the management of aneurysms that include the distal aortic arch. The Gore TAG thoracic branch endoprosthesis (W. L. Gore & Associates, Inc, Flagstaff, Ariz), an investigational device, allows for graft placement proximal to the left subclavian artery and incorporates a single side branch for left subclavian perfusion.

RESULTS

All 31 patients (100%) had undergone successful implantation of the investigational device in landing zone 2. Men slightly outnumbered women (51.6%). Their average age was 74.1 ± 10.4 years. The aneurysm morphology was fusiform in 12 and saccular in 19 patients, with a mean maximum aortic diameter of 54.8 ± 10.9 mm. The mean follow-up period for the cohort was 25.2 ± 11.1 months. We have reported the patient outcomes at 1 month and 1 year. At 1 month, the side branch patency was 100% and the freedom from core laboratory-reported device-related endoleak (types I and III) was 96.7%, without 30-day death or permanent paraplegia. One patient experienced a procedure-related stroke. Through 1 year, five patients had died; none of the deaths were related to the device or procedure (clinical endpoint committee adjudicated). One thoracic reintervention was required. No conversions were required, and no aneurysm growth (core laboratory) was reported. One case of the loss of side branch patency was diagnosed in the left subclavian artery in an asymptomatic individual from computed tomography at 6 months, with no reported subsequent adverse events due to loss of patency. Endoleaks were reported by the core laboratory in five patients at 12 months (two, type II; and three, indeterminate).

CONCLUSIONS

The present investigational device exemption feasibility study has reported the preliminary results of the use of a single side branch endograft to treat patients with proximal descending thoracic aortic aneurysms.

Unique characteristics of the type B aortic dissection patients with malperfusion in the Vascular Quality Initiative

OBJECTIVE

Type B aortic dissection (TBAD) complicated by malperfusion carries high morbidity and mortality. The present study was undertaken to compare the characteristics of malperfusion and uncomplicated cohorts and to evaluate the long-term differences in survival using a granular, national registry.

METHODS

Patients with TBAD entered into the thoracic endovascular aortic repair/complex endovascular aortic repair module of the Vascular Quality Initiative from 2010 to 2019 were included. The demographic, radiographic, operative, postoperative, in-hospital, and long-term reintervention data were compared between the malperfusion and uncomplicated TBAD groups using t tests and χ² analysis, as appropriate. Overall survival was compared using Cox regression to generate survival curves.

RESULTS

Of the 2820 included patients, 2267 had uncomplicated TBAD and 553 had malperfusion. The patients with malperfusion were younger (age, 55.8 vs 61.2 years; P < .001), were more often male (79.7% vs 68.1%; P < .001), had a higher preoperative creatinine (1.8 vs 1.1 mg/dL; P < .001), had more often presented with an American Society of Anesthesiologists class of 4 or 5 (81.9% vs 58.4%; P < .001), and had more often presented with urgent status (77.4% vs 32.8%; P < .001). In contrast, the uncomplicated TBAD group had had more medical comorbidities, including coronary artery disease and chronic obstructive pulmonary disease, and a larger aortic diameter (4.0 cm vs 4.9 cm; P < .001). The malperfusion group more frequently had proximal zones of disease in zones 0 to 2 (38.6% vs 31.5%; P = .002) and distal zones of disease in zones 9 and above (78.7% vs 46.2%; P < .001), with a greater number of aortic zones traversed (7.7 vs 5.1; P < .001) and a greater frequency of dissection extension into branch vessels (61.8% vs 23.1%; P < .001). Patients with malperfusion also exhibited greater case complexity, with a greater need for branch vessel stenting and longer procedure times. The overall incidence of postoperative complications was greater in the malperfusion group (39.4% vs 17.1%; P < .001) and included a greater rate of spinal cord ischemia (6.3% vs 2.2%; P < .001), acute kidney injury (10.4% vs 0.9%; P < .001), and in-hospital mortality (11.6% vs 5.6%; P < .001). In-hospital reintervention was also greater for the malperfusion patients (14.5% vs 7.4%; P < .001), although the incidence of long-term reinterventions was similar between the two groups (8.7% vs 9.7%; P = .548). A proximal zone of disease in zone 0 to 2 was associated with decreased survival. In contrast, a distal zone of disease in 9 and above, in-hospital reintervention, and long-term follow-up were associated with increased survival. Despite these differences, long-term survival did not differ between the malperfusion and uncomplicated groups (P = .320.) CONCLUSIONS: Patients presenting with TBAD and malperfusion represent a unique cohort. Despite the greater need for branch vessel stenting and in-hospital reintervention, they had similar long-term reintervention rates and survival compared with those with uncomplicated TBAD. These data lend insight with regard to the observed differences between uncomplicated and malperfusion TBAD.

Is hemiarch replacement adequate in acute type A aortic dissection repair in patients with arch branch vessel dissection without cerebral malperfusion?

OBJECTIVE

The study objective was to determine if hemiarch replacement is an adequate arch management strategy for patients with acute type A aortic dissection and arch branch vessel dissection but no cerebral malperfusion.

METHODS

From January 2008 to August 2019, 479 patients underwent open acute type A aortic dissection repair. After excluding those with aggressive arch replacement (n = 168), cerebral malperfusion syndrome (n = 34), and indeterminable arch branch vessel dissection (n = 1), 276 patients with an acute type A aortic dissection without cerebral malperfusion syndrome who underwent hemiarch replacement comprised this study. Patients were then divided into those with arch branch vessel dissection (n = 133) and those with no arch branch vessel dissection (n = 143).

RESULTS

The median age of the entire cohort was 62 years, with the arch branch vessel dissection group being younger (60 vs 62 years, P = .048). Both groups had similar aortic arch and descending thoracic aortic diameters, with significantly more DeBakey type I dissections (100% vs 80%) in the arch branch vessel dissection group. The arch branch vessel dissection group had more aortic root replacement (36% vs 27%, P = .0035) and longer aortic crossclamp times (153 vs 128 minutes, P = .007). Postoperative outcomes were similar between the arch branch vessel dissection and no arch branch vessel dissection groups, including stroke (10% vs 5%, P = .12) and operative morality (7% vs 5%, P = .51). The arch branch vessel dissection group had a significantly greater cumulative incidence of reoperation (8-year: 19% vs 4%, P = .04) with a hazard ratio of 2.89 (95% confidence interval, 1.01-8.27; P = .048), which was similar between groups among only DeBakey type I dissections (8-year: 19% vs 5%, P = .11). The 8-year survival was similar between the arch branch vessel dissection and no arch branch vessel dissection groups (76% vs 74%, P = .30).

CONCLUSIONS

Hemiarch replacement was adequate for patients with acute type A aortic dissection with arch branch vessel dissection without cerebral malperfusion syndrome, but carried a higher risk of late reoperation.

Numerical knockouts-In silico assessment of factors predisposing to thoracic aortic aneurysms

Myriad risk factors–including uncontrolled hypertension, aging, and diverse genetic mutations–contribute to the development and enlargement of thoracic aortic aneurysms. Detailed analyses of clinical data and longitudinal studies of murine models continue to provide insight into the natural history of these potentially lethal conditions. Yet, because of the co-existence of multiple risk factors in most cases, it has been difficult to isolate individual effects of the many different factors or to understand how they act in combination. In this paper, we use a data-informed computational model of the initiation and progression of thoracic aortic aneurysms to contrast key predisposing risk factors both in isolation and in combination; these factors include localized losses of elastic fiber integrity, aberrant collagen remodeling, reduced smooth muscle contractility, and dysfunctional mechanosensing or mechanoregulation of extracellular matrix along with superimposed hypertension and aortic aging. In most cases, mild-to-severe localized losses in cellular function or matrix integrity give rise to varying degrees of local dilatations of the thoracic aorta, with enlargement typically exacerbated in cases wherein predisposing risk factors co-exist. The simulations suggest, for the first time, that effects of compromised smooth muscle contractility are more important in terms of dysfunctional mechanosensing and mechanoregulation of matrix than in vessel-level control of diameter and, furthermore, that dysfunctional mechanobiological control can yield lesions comparable to those in cases of compromised elastic fiber integrity. Particularly concerning, therefore, is that loss of constituents such as fibrillin-1, as in Marfan syndrome, can compromise both elastic fiber integrity and mechanosensing.

Aneurysms are local dilatations of the arterial wall that are responsible for significant disability and death. Detailed analyses of clinical data continue to provide insight into the natural history of these potentially lethal conditions, with myriad risk factors–including uncontrolled hypertension, aging, and diverse genetic mutations–contributing to their development and enlargement. Yet, because of the co-existence of these risk factors in most cases, it has been difficult to isolate individual effects or to understand how they act in combination. In this paper, we use a computational model of the initiation and progression of thoracic aortic aneurysms to contrast key predisposing factors both in isolation and in combination as well as with superimposed hypertension and aging. The present study recovers many findings from mouse models but with new and important observations that promise to guide in vivo and ex vivo studies as we seek to understand and eventually better treat these complex, multi-factorial lesions, with data-informed patient-specific computations eventually the way forward.

Clinical and Morphologic Outcomes of Endovascular Repair for Subacute and Chronic Type B Aortic Dissection

BACKGROUND

The objective of the study was to assess long-term remodeling, survival, and reintervention outcomes after thoracic endovascular aortic repair (TEVAR) for subacute and chronic type B aortic dissection (TBAD).

METHODS

All patients who underwent TEVAR for subacute or chronic TBAD at a tertiary referral center between 1999 and 2015 were included in this cohort study. The primary outcome was aortic remodeling, and secondary outcomes included survival, rate of major complications, and reinterventions.

RESULTS

Fifty patients were included, with mean age of 62.4 years, 10 (20%) DeBakey type IIIA and 40 (80%) DeBakey type IIIB dissection; 45 standard TEVAR, 2 branched TEVAR, 3 TEVAR combined with fenestrated or branched EVAR. Indication for TEVAR was intact (n = 40) or ruptured (n = 1) postdissection aneurysm, hypoperfusion (n = 4), treatment-refractory pain (n = 2), or a combination (n = 3). Mean clinical follow-up was 76 months, and median radiological follow-up was 46 months. Thirty-day survival was 96%, stroke 4%, renal failure 0%, paraplegia 0%. Three- and five-year survival was 92% (95% confidence interval (CI) [79; 97]) and 77% (95% CI [61; 87]), respectively. Of 19 late deaths, 6 were confirmed aorta related. Five-year freedom from reintervention was 69% (95% CI [53-80]). Distal stent graft extension due to aortic dilatation composed most reinterventions. Mean maximal aortic diameter was 58.7 mm preoperatively and 51.9 mm on last follow-up (P = 0.003). On thoracic level, true lumen expanded (+10.0 mm, 95% CI [6.4; 13.6]) (P < 0.001) and false lumen decreased (-11.9 mm, 95% CI [-15.2; -8.5]) (P < 0.001) from baseline to the last computed tomography. In the abdominal aorta, true lumen diameter change was +3.1 mm (95% CI [1.4; 4.8]) (P = 0.001); false lumen diameter change was +1.0 mm (95% CI [-1.8; 3.8]) (P = 0.464).

CONCLUSIONS

TEVAR for subacute and chronic TBAD results in favorable remodeling of the thoracic but not the abdominal aorta. Five-year survival is almost 80%, but late aortic deaths still occur. Aortic dilatation distal to the treated segment requiring reintervention is common, emphasizing the importance of follow-up.

Wall Stress Distribution in Bicuspid Aortic Valve-Associated Ascending Thoracic Aortic Aneurysms

BACKGROUND

Bicuspid aortic valve-associated ascending thoracic aortic aneurysms (BAV-aTAAs) carry a risk of acute type A dissection. Biomechanically, dissection may occur when wall stress exceeds wall strength. Our aim was to develop patient-specific computational models of BAV-aTAAs to determine magnitudes of wall stress by anatomic regions.

METHODS

Patients with BAV-aTAA diameter greater than 4.5 cm (n = 41) underwent electrocardiogram-gated computed tomography angiography. Three-dimensional aneurysm geometries were reconstructed after accounting for prestress and loaded to systemic pressure. Finite element analyses were performed with fiber-embedded hyperelastic material model using LS-DYNA software (LSTC Inc, Livermore, CA) to obtain wall stress distributions. The 99th percentile longitudinal and circumferential stresses were determined at systole.

RESULTS

The 99th percentile longitudinal wall stresses for BAV-aTAAs at sinuses of Valsalva, sinotubular junction (STJ), and ascending aorta were 361 ± 59.8 kPa, 295 ± 67.2 kPa, and 224 ± 37.6 kPa, respectively, with significant differences in ascending aorta vs sinuses (P< 1 × 10-13) and STJ (P < 1 × 10-6). The 99th percentile circumferential wall stresses were 474 ± 88.2 kPa, 634 ± 181.9 kPa, and 381 ± 54.0 kPa for sinuses, the STJ, and the ascending aorta, respectively, with significant differences in the ascending aorta vs sinuses (P = .002) and STJ (P < 1 × 10-13).

CONCLUSIONS

Wall stresses, both circumferential and longitudinal, were greater in the aortic root, sinuses, and STJ than in the ascending aorta on BAV-aTAAs. These results fill a fundamental knowledge gap regarding biomechanical stress distribution in BAV-aTAA patients, which when related to wall strength may provide prognostication of aTAA dissection risk by patient-specific modeling.

Thoracic aortic remodeling with endografting after a decade of thoracic endovascular aortic repair experience

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) results have been studied in short-term time frames. This study aimed to evaluate midterm and long-term outcomes of TEVAR, emphasizing postoperative aortic remodeling and need for reintervention.

METHODS

This is an institutional retrospective review of TEVAR for isolated descending thoracic aortic aneurysms. Data were collected from 2004 to 2018. Primary outcomes studied included aneurysm sac remodeling, freedom from reintervention, and all-cause mortality. Other outcomes studied include endoleak rates, neurologic complication rates, and any overall postoperative complication rates.

RESULTS

During the study period, 219 patients underwent TEVAR for descending thoracic aortic aneurysms. The median effect of TEVAR on sac diameter was a 0.7-cm decrease in size (interquartile range, -1.4 to 0.0 cm). During the study period, 80% (n = 147) of patients experienced aneurysm sac regression or stability. Perioperative neurologic complications occurred in 16% (n = 34) of patients. Significant predictors of sac growth were endoleak (odds ratio [OR], 65; P < .001), preoperative carotid-subclavian bypass (OR, 8; P = .003), and graft oversizing <20% (OR, 15; P = .046). Every 1-mm increase in aortic diameter at the proximal TEVAR landing zone led to an increased odds of endoleak (OR, 2; P = .049). Access complications (OR, 8) and subclavian artery coverage (OR, 6) significantly increased the odds of reintervention, whereas every percentage of graft oversizing protected against reintervention (OR, 0.005). Life-table analysis revealed an overall survival of 78% (71%-83%) at median follow-up. At 3 years, survival was 88% (80%-93%) for those with aneurysm sac stability or regression, whereas it was 70% (49%-84%) for those with aneurysm sac growth (P = .0402). Cox proportional hazards model showed that the only protective factor for mortality was percentage oversizing, with every 1% of oversizing having a hazard ratio (HR) of <.001 (P = .032). This was counterbalanced by the fact that patients with graft oversizing >30% had an increased odds of mortality with HR >10 (P = .049). Other significant factors that increased the odds of mortality included endoleak (HR, 3.6; P = .033), diabetes (HR, 4.1; P = .048), age (every 1-year increase in age; HR, 1.2; P = .002), year of surgery (every year subsequent to 2004; HR, 1.3; P = .012), and peripheral artery disease (HR, 5.2; P = .041).

CONCLUSIONS

The majority of patients (80%) experience sac stability or regression after TEVAR, which offers a clear survival advantage. Endoleaks are predictive of sac growth, conferring increased mortality. Rigorous surveillance is necessary to prevent future aortic events through reintervention.

Computational prediction of hemodynamical and biomechanical alterations induced by aneurysm dilatation in patient-specific ascending thoracic aortas

The aim of the present work is to propose a robust computational framework combining computational fluid dynamics (CFD) and 4D flow MRI to predict the progressive changes in hemodynamics and wall rupture index (RPI) induced by aortic morphological evolutions in patients harboring ascending thoracic aortic aneurysms (ATAAs). An analytical equation has been proposed to predict the aneurysm progression based on age, sex, and body surface area. Parameters such as helicity, wall shear stress (WSS), time-averaged WSS, oscillatory shear index, relative residence time, and viscosity were evaluated for two patients at different stages of aneurysm growth, and compared with age-sex-matched healthy subjects. The study shows that evolution of hemodynamics and RPI, despite being very slow in ATAAs, is strongly affected by morphological alterations and, in turn could impact biomechanical factors and aortic mechanobiology. An aspect of the current work is that the patient-specific 4D MRI data sets were obtained with a follow-up of 1 year and the measured time-averaged velocity maps and flow eccentricity were compared with the CFD simulation for validation. The computational framework presented here is capable of capturing the blood flow patterns and the hemodynamic descriptors during the various stages of aneurysm growth. Further investigations will be conducted in order to verify these results on a larger cohort of patients and with long follow-up times to finally elucidate the link between deranged hemodynamics, AA geometry, and wall mechanical properties in ATAAs.

Inherited Thoracic Aortic Disease: New Insights and Translational Targets

Inherited thoracic aortopathies denote a group of congenital conditions that predispose to disease of the thoracic aorta. Aortic wall weakness and abnormal aortic hemodynamic profiles predispose these patients to dilatation of the thoracic aorta, which is generally silent but can precipitate aortic dissection or rupture with devastating and often fatal consequences. Current strategies to assess the future risk of aortic dissection or rupture are based primarily on monitoring aortic diameter. However, diameter alone is a poor predictor of risk, with many patients experiencing dissection or rupture below current intervention thresholds. Developing tools that improve the risk assessment of those with aortopathy is internationally regarded as a research priority. A robust understanding of the molecular pathways that lead to aortic wall weakness is required to identify biomarkers and therapeutic targets that could improve patient management. Here, we summarize the current understanding of the genetically determined mechanisms underlying inherited aortopathies and critically appraise the available blood biomarkers, imaging techniques, and therapeutic targets that have shown promise for improving the management of patients with these important and potentially fatal conditions.

Impact of a Higher Body Mass Index on Prolonged Intubation in Patients Undergoing Surgery for Acute Thoracic Aortic Dissection

BACKGROUND

In recent years, obese patients presenting with acute thoracic aortic dissection have not been uncommon and there are often pulmonary complications among them. Whether a higher body mass index (BMI) is associated with more pulmonary complications or even a higher mortality rate has yet to be determined. This study aimed to evaluate the effects of higher BMI on pulmonary complications and other surgical outcomes.

METHODS

A total of 404 patients who underwent acute thoracic aortic dissection surgery were retrospectively studied. They were divided into three groups based on their BMI: normal weight (BMI 18.5 to <25 kg/m², n=173), overweight (BMI 25 to <30 kg/m², n=145) and obese (BMI ≥30 kg/m², n=86). Clinical data were collected and analysed among groups.

RESULTS

No statistical significance was detected among the groups for postoperative complications, in-hospital mortality and hospital or ICU stay, except for prolonged intubation, the proportion of which was highest in the obese group followed by the overweight and normal groups (40.7% vs 29% vs 11%, respectively; p<0.001). Furthermore, logistic regression analysis showed that postoperative renal failure (OR=16.984) and cardiopulmonary bypass time (OR=1.013) were independent risk factors for in-hospital mortality, while higher BMI (OR=7.148 for BMI ≥25 and 18.967 for BMI ≥30), transfused red blood cells (OR=1.004), and postoperative renal failure (OR=7.386) were independent risk factors for prolonged ventilation (p<0.05).

CONCLUSION

Body mass index had no effect on in-hospital mortality but may be closely correlated with prolonged intubation for patients undergoing aortic dissection surgery. This finding suggests that these patients should receive more aggressive pulmonary management.

Prosthetic aortic graft replacement of the ascending thoracic aorta alters biomechanics of the native descending aorta as assessed by transthoracic echocardiography

Introduction

In patients with ascending aortic (AA) aneurysms, prosthetic graft replacement yields benefit but risk for complications in the descending aorta persists. Longitudinal impact of AA grafts on native descending aortic physiology is poorly understood.

Methods

Transthoracic echocardiograms (echo) in patients undergoing AA elective surgical grafting were analyzed: Descending aortic deformation indices included global circumferential strain (GCS), time to peak (TTP) strain, and fractional area change (FAC). Computed tomography (CT) was used to assess aortic wall thickness and calcification.

Results

46 patients undergoing AA grafting were studied; 65% had congenital or genetically-associated AA (30% bicuspid valve, 22% Marfan, 13% other): After grafting (6.4±7.5 months), native descending aortic distension increased, irrespective of whether assessed based on circumferential strain or area-based methods (both p<0.001). Increased distensibility paralleled altered kinetics, as evidenced by decreased time to peak strain (p = 0.01) and increased velocity (p = 0.002). Augmented distensibility and flow velocity occurred despite similar pre- and post-graft blood pressure and medications (all p = NS), and was independent of pre-surgical aortic regurgitation or change in left ventricular stroke volume (both p = NS). Magnitude of change in GCS and FAC was 5–10 fold greater among patients with congenital or genetically associated AA vs. degenerative AA (p<0.001), paralleling larger descending aortic size, greater wall thickness, and higher prevalence of calcific atherosclerotic plaque in the degenerative group (all p<0.05). In multivariate analysis, congenital/genetically associated AA etiology conferred a 4-fold increment in magnitude of augmented native descending aortic strain after proximal grafting (B = 4.19 [CI 1.6, 6.8]; p = 0.002) independent of age and descending aortic size.

Conclusions

Prosthetic graft replacement of the ascending aorta increases magnitude and rapidity of distal aortic distension. Graft effects are greatest with congenital or genetically associated AA, providing a potential mechanism for increased energy transmission to the native descending aorta and adverse post-surgical aortic remodeling.

Dynamic Indicators That Impact the Outcomes of Thoracic Endovascular Aortic Repair in Complicated Type B Aortic Dissection

PURPOSE

To investigate dynamic variables obtained from retrospective computed tomography angiography for ability to predict thoracic endovascular aortic repair (TEVAR) outcomes in patients with complicated type B aortic dissection (cTBAD).

MATERIALS AND METHODS

Seventy-nine patients with cTBAD who received TEVAR from March 2009 to June 2018 were retrospectively enrolled. Relative true lumen area (r-TLA) was computed at the level of tracheal bifurcation every 5% of all R-R intervals. Parameters that reflect the state of intimal motion were evaluated, including difference between maximum and minimum r-TLA (D-TLA) and true lumen collapse. The endpoints comprised early (≤ 30 days) and late (> 30 days) outcomes after intervention.

RESULTS

Overall early mortality rate was 13.9% (11/79), and early adverse events rate was 24.1% (19/79). Patients who received TEVAR within 2 days of symptom onset demonstrated the worst outcomes. A longer time of r-TLA < 25% in 1 cardiac cycle (P = .049) and larger D-TLA (P < .001) were correlated to an increased early death. In addition, D-TLA was an independent predictor of early mortality. Area under the curve of D-TLA was 0.849 (95% confidence interval 0.730-0.967) for predicting early mortality and 0.742 (95% CI 0.611-0.873) for predicting early adverse events. Survival and event-free survival rates during follow-up were decreased in the D-TLA > 21.5% group compared with the D-TLA ≤ 21.5% group (all P < .001).

CONCLUSIONS

Larger D-TLA is correlated with worse postoperative outcomes and might be a crucial parameter for future risk stratification in patients with cTBAD.

Diastolic, but not systolic, blood pressure at admission is associated with aortic-related adverse events in type B dissection after thoracic endovascular aortic repair

BACKGROUND

Hypertension is the most important risk factor for aortic dissection. We aimed to assess the association of systolic blood pressure (SBP) and diastolic blood pressure (DBP) at admission with aortic-related adverse events (ARAE) after thoracic endovascular aortic repair (TEVAR).

METHODS

All patients (n = 269) admitted with type B aortic dissection (BAD) for TEVAR were included. ARAE at 3, 24, and 60 months were evaluated as outcomes. Cox proportional regression analysis was performed.

RESULTS

No variables were found to be predictors of 3-month ARAE by multiple analysis. Independent predictors of 24-month ARAE were DBP at admission (hazard ratio [HR] per 10 mm Hg decrement, 1.318; 95% confidence interval [CI] 1.059-1.641; p = 0.013), cerebrovascular accident (HR 1.965; 95% CI 1.097-3.522; p = 0.023) and obesity (HR 2.922; 95% CI 1.096-7.795; p = 0.032). DBP at admission (HR per 10 mm Hg decrement, 1.276; 95% CI 1.038-1.569; p = 0.021) was also a predictor of 60-month ARAE. In the non-chronic group (n = 223), DBP at admission was evaluated as an independent predictor of 3-month (HR per 10 mm Hg decrement, 1.809; 95% CI 1.084-3.018; p = 0.023), 24-month (HR per 10 mm Hg decrement, 1.344; 95% CI 1.070-1.688; p = 0.011) and 60-month (HR per 10 mm Hg decrement, 1.338; 95% CI 1.065-1.682; p = 0.013) ARAE. In the chronic group (n = 46), no variables were found to be independent predictors of 3-month, 24-month, or 60-month ARAE.

CONCLUSIONS

DBP at admission can predict ARAE in patients with BAD after TEVAR, whereas SBP was not associated with ARAE. The relationship between DBP at admission and outcomes appears to be more prominent in non-chronic patients.

Epidural Corticosteroids, Lumbar Spinal Drainage, and Selective Hemodynamic Control for the Prevention of Spinal Cord Ischemia in Thoracoabdominal Endovascular Aortic Repair: A New Clinical Protocol

INTRODUCTION

In patients undergoing thoracoabdominal aorta repair, spinal cord ischemia (SCI) remains one of the most common and important complications resulting in transient paraparesis through to permanent flaccid paraplegia. In this manuscript, after a brief introduction to spinal cord ischemia complication and its prevention in thoracoabdominal endovascular aortic repair (TEVAR), we propose a new clinical protocol potentially able to prevent such complication.

METHODS

The proposed protocol suggests the use of high dosages of corticosteroids by epidural route, along with drainage of cerebrospinal fluid and controlled vascular hypertension, to reduce the incidence of SCI in TEVAR. Moreover, we paid particular attention to the control of the hemodynamic parameters to obtain adequate peripheral tissue perfusion (oxygen delivery), including in the spinal cord.

RESULTS

We applied this new protocol in 50 consecutive patients treated with TEVAR for thoracoabdominal aortic aneurysms (TAAs); 47 patients completed the procedure: 27 patients Crawford type I and 20 Crawford type II. Three patients died during surgery because of untreatable aneurysm rupture. The results show that in all patients there were no cases of SCI, after 5 days from TEVAR.

DISCUSSION

To the best of our knowledge, there are no clinical studies on the use of epidural corticosteroids in patients undergoing treatment of aortic syndrome (both in "open surgery" and endovascular aortic repair). This initial study on 50 consecutive patients has shown that the clinical protocol used could be of great interest to prevent one of the worse complications of TEVAR. Its limitations are the low number of patients studied till now, and the non-randomized protocol adopted. Further studies would be necessary.

CONCLUSION

Our experience and the results obtained with this new perioperative protocol with epidural corticosteroid and accurate hemodynamic control have been encouraging and it seems a valid proposal to be explored in future by well-structured prospective, randomized protocols.

Decreased rotational flow and circumferential wall shear stress as early markers of descending aorta dilation in Marfan syndrome: a 4D flow CMR study

BACKGROUND

Diseases of the descending aorta have emerged as a clinical issue in Marfan syndrome following improvements in proximal aorta surgical treatment and the consequent increase in life expectancy. Although a role for hemodynamic alterations in the etiology of descending aorta disease in Marfan patients has been suggested, whether flow characteristics may be useful as early markers remains to be determined.

METHODS

Seventy-five Marfan patients and 48 healthy subjects were prospectively enrolled. In- and through-plane vortexes were computed by 4D flow cardiovascular magnetic resonance (CMR) in the thoracic aorta through the quantification of in-plane rotational flow and systolic flow reversal ratio, respectively. Regional pulse wave velocity and axial and circumferential wall shear stress maps were also computed.

RESULTS

In-plane rotational flow and circumferential wall shear stress were reduced in Marfan patients in the distal ascending aorta and in proximal descending aorta, even in the 20 patients free of aortic dilation. Multivariate analysis showed reduced in-plane rotational flow to be independently related to descending aorta pulse wave velocity. Conversely, systolic flow reversal ratio and axial wall shear stress were altered in unselected Marfan patients but not in the subgroup without dilation. In multivariate regression analysis proximal descending aorta axial (p = 0.014) and circumferential (p = 0.034) wall shear stress were independently related to local diameter.

CONCLUSIONS

Reduced rotational flow is present in the aorta of Marfan patients even in the absence of dilation, is related to aortic stiffness and drives abnormal circumferential wall shear stress. Axial and circumferential wall shear stress are independently related to proximal descending aorta dilation beyond clinical factors. In-plane rotational flow and circumferential wall shear stress may be considered as an early marker of descending aorta dilation in Marfan patients.

Assessment of the regional distribution of normalized circumferential strain in the thoracic and abdominal aorta using DENSE cardiovascular magnetic resonance

BACKGROUND

Displacement Encoding with Stimulated Echoes (DENSE) cardiovascular magnetic resonance (CMR) of the aortic wall offers the potential to improve patient-specific diagnostics and prognostics of diverse aortopathies by quantifying regionally heterogeneous aortic wall strain in vivo. However, before regional mapping of strain can be used to clinically assess aortic pathology, an evaluation of the natural variation of normal regional aortic kinematics is required.

METHOD

Aortic spiral cine DENSE CMR was performed at 3 T in 30 healthy adult subjects (range 18 to 65 years) at one or more axial locations that are at high risk for aortic aneurysm or dissection: the infrarenal abdominal aorta (IAA, n = 11), mid-descending thoracic aorta (DTA, n = 17), and/or distal aortic arch (DAA, n = 11). After implementing custom noise-reduction techniques, regional circumferential Green strain of the aortic wall was calculated across 16 sectors around the aortic circumference at each location and normalized by the mean circumferential strain for comparison between individuals.

RESULTS

The distribution of normalized circumferential strain (NCS) was heterogeneous for all locations evaluated. Despite large differences in mean strain between subjects, comparisons of NCS revealed consistent patterns of strain distribution for similar groupings of patients by axial location, age, and/or mean displacement angle. NCS at local systole was greatest in the lateral/posterolateral walls in the IAAs (1.47 ± 0.27), medial wall in anteriorly displacing DTAs (1.28 ± 0.20), lateral wall in posteriorly displacing DTAs (1.29 ± 0.29), superior curvature in DAAs < 50 years-old (1.93 ± 0.22), and medial wall in DAAs > 50 years (2.29 ± 0.58). The distribution of strain was strongly influenced by the location of the vertebra and other surrounding structures unique to each location.

CONCLUSIONS

Regional in vivo circumferential strain in the adult aorta is unique to each axial location and heterogeneous around its circumference, but can be grouped into consistent patterns defined by basic patient-specific metrics following normalization. The heterogeneous strain distributions unique to each group may be due to local peri-aortic constraints (particularly at the aorto-vertebral interface), heterogeneous material properties, and/or heterogeneous flow patterns. These results must be carefully considered in future studies seeking to clinically interpret or computationally model patient-specific aortic kinematics.

Association between acute aortic dissection and the distribution of aortic calcification

Objective

Aortic calcification (AC) is associated with increased risks of cardiovascular events and mortality. Numerous studies have explored the association between calcification and abdominal artery aneurysm. However, evidence regarding the association between AC and acute aortic dissection (AAD) is limited. We aimed to evaluate the association between AC-related variables and the development of intimal tear (IT) in patients with AAD.

Methods

We conducted a retrospective observational study involving 64 patients with type A AAD and 32 patients with type B AAD from February, 2011 to January, 2017 at a tertiary referral medical center in Taiwan. We used the default analysis module “calcification score analysis” to calculate all the calcification variables, including AC scores and volume.

Results

We identified an association between AC and AAD. Patients with AAD had a greater AC volume in the aortic arch and greater AC scores for both the ascending aorta and the aortic arch than did patients without AAD. However, hypertension and coronary artery disease, rather than AC remained to be the independent risk factor for AAD in multivariate analysis. Patients with type A AAD had greater mean and cumulative AC volumes in the aortic arch, greater cumulative AC volumes in the whole aorta and higher cumulative AC scores in the aortic arch than did patients with type B AAD. ACs were superimposed on ITs in nearly half of the patients with AAD. In patients with type A AAD, AC was more commonly located distal to the IT and farther from the IT.

Conclusions

We identified the associations between AC-related variables and the location of IT in patients with AAD. However, AC was not an independent risk factor for AAD. The distribution of AC was different between patients with type A and type B AAD.

Intracellular retention of mutant lysyl oxidase leads to aortic dilation in response to increased hemodynamic stress

Heterozygous missense mutations in lysyl oxidase (LOX) are associated with thoracic aortic aneurysms and dissections. To assess how LOX mutations modify protein function and lead to aortic disease, we studied the factors that influence the onset and progression of vascular aneurysms in mice bearing a Lox mutation (p.M292R) linked to aortic dilation in humans. We show that mice heterozygous for the M292R mutation did not develop aneurysmal disease unless challenged with increased hemodynamic stress. Vessel dilation was confined to the ascending aorta although both the ascending and descending aortae showed changes in vessel wall structure, smooth muscle cell number and inflammatory cell recruitment that differed between wild-type and mutant animals. Studies with isolated cells found that M292R-mutant Lox is retained in the endoplasmic reticulum and ultimately cleared through an autophagy/proteasome pathway. Because the mutant protein does not transit to the Golgi where copper incorporation occurs, the protein is never catalytically active. These studies show that the M292R mutation results in LOX loss-of-function due to a secretion defect that predisposes the ascending aorta in mice (and by extension humans with similar mutations) to arterial dilation when exposed to risk factors that impart stress to the arterial wall.

Clinical Implications of Identifying Pathogenic Variants in Individuals With Thoracic Aortic Dissection

BACKGROUND

Thoracic aortic dissection is an emergent life-threatening condition. Routine screening for genetic variants causing thoracic aortic dissection is not currently performed for patients or family members.

METHODS

We performed whole exome sequencing of 240 patients with thoracic aortic dissection (n=235) or rupture (n=5) and 258 controls matched for age, sex, and ancestry. Blinded to case-control status, we annotated variants in 11 genes for pathogenicity.

RESULTS

Twenty-four pathogenic variants in 6 genes (COL3A1, FBN1, LOX, PRKG1, SMAD3, and TGFBR2) were identified in 26 individuals, representing 10.8% of aortic cases and 0% of controls. Among dissection cases, we compared those with pathogenic variants to those without and found that pathogenic variant carriers had significantly earlier onset of dissection (41 versus 57 years), higher rates of root aneurysm (54% versus 30%), less hypertension (15% versus 57%), lower rates of smoking (19% versus 45%), and greater incidence of aortic disease in family members. Multivariable logistic regression showed that pathogenic variant carrier status was significantly associated with age <50 (odds ratio [OR], 5.5; 95% CI, 1.6-19.7), no history of hypertension (OR, 5.6; 95% CI, 1.4-22.3), and family history of aortic disease (mother: OR, 5.7; 95% CI, 1.4-22.3, siblings: OR, 5.1; 95% CI, 1.1-23.9, children: OR, 6.0; 95% CI, 1.4-26.7).

CONCLUSIONS

Clinical genetic testing of known hereditary thoracic aortic dissection genes should be considered in patients with a thoracic aortic dissection, followed by cascade screening of family members, especially in patients with age-of-onset <50 years, family history of thoracic aortic disease, and no history of hypertension.

Optimal blood pressure control for patients after thoracic endovascular aortic repair of type B aortic dissection

BACKGROUND

Guidelines recommend tight systolic blood pressure (SBP) control for favorable outcomes of type B aortic dissection (BAD) but are still limited by the optimal cut-off value of SBP. The purpose of this study was to evaluate the optimal cut-off value of SBP in BAD patients after thoracic endovascular aortic repair (TEVAR).

METHODS

From January 2011 to April 2017, 269 consecutive patients with BAD after TEVAR were included in the study. All patients were followed up according to a strict follow-up protocol. Cox regression analysis was used to examine the association between SBP at discharge and 90-day aortic related adverse events (ARAE).

RESULTS

All 269 patients completed 90 days of follow-up, and the unadjusted ARAE-free rates at 90-day was 95.1 ± 1.3%. The cut-off value of SBP at discharge identified by receiver operator curve was 130 mmHg for 90-day ARAE. In multivariable models, binary SBP at discharge was significant associated with 90-day ARAE (HR 3.780; 95% CI 1.236-11.556; p = 0.020). Hybrid operation (OR 2.046; 95%CI 1.015-4.122; p = 0.045) and insertion of ≥2 stents (OR 2.950; 95%CI 1.172-7.426; p = 0.022) were demonstrated to be independently associated with poor SBP control (SBP > 130 mmHg) using Logistic analysis.

CONCLUSIONS

The optimal cut-off value of SBP at discharge was 130 mmHg which can be used to predict short-term ARAE. Blood pressure in patients with hybrid operation and ≥ 2 stents should be given more focus.

Distal Extended Endovascular Aortic Repair PETTICOAT: A Modified Technique to Improve False Lumen Remodeling in Acute Type B Aortic Dissection

BACKGROUND

Data from the literature suggest that in patients with acute, complicated type B aortic dissection (cTBAD), initial successful treatment with thoracic endovascular aneurysm repair (TEVAR) is not necessarily associated with favorable remodeling of the dissected aorta during follow-up, and long-term results indicate that TEVAR failed to completely suppress false lumen patency. Sealing of all relevant distal reentries, infrarenal and/or iliac, seems to be the key issue to induce total false lumen thrombosis in abdominal aorta as well as the iliac arteries, especially in complicated patients presenting with malperfusion or complete true lumen collapse.

MATERIALS AND METHODS

Of the 34 consecutive patients diagnosed with cTBAD at our hospital from January 2015 to April 2018, 30 had complicated dissections receiving endovascular treatment according to the standard Provisional ExTension To Induce COmplete ATtachment (PETTICOAT) technique and were excluded from this study, whereas 4 patients with radiologic evidence of multiple reentry tears at detached lumbar arteries and iliac bifurcation with complete true lumen collapse and clinical evidence of malperfusion were treated with a modified PETTICOAT technique with distal extension of the aortic stent, balloon expansion of the stented true lumen, and use of the AFX bifurcated endograft system to preserve the natural aortic bifurcation and provide complete distal sealing of reentry tears.

RESULTS

Primary technical success was achieved in all patients. No postoperative deaths were observed, but 1 patient experienced an hemorrhagic shock on the second postoperative day. No patient suffered postoperative stroke, paraplegia, paraparesis, or acute renal failure.

CONCLUSIONS

Using an abdominal aortic bifurcated endograft with PETTICOAT to treat acute cTBAD seems to be a feasible approach in high-risk patients to improve aortic remodeling. The AFX bifurcated endograft system meets the requirements of anatomical fixation and sealing of distal tears.

Type B Aortic Dissection after Nellix Endovascular Aneurysm Sealing

BACKGROUND

Endovascular aneurysm sealing (EVAS) was developed with the intention of expanding the anatomical limitations of conventional endovascular aneurysm repair devices and decrease rates of reintervention secondary to migration and type II endoleaks in treatment of abdominal aortic aneurysms.¹ Since its inception, EVAS has gained much popularity especially for patients with concomitant common iliac aneurysms, with good long-term durability suggested by several studies. Currently, the known complications of EVAS, while considered uncommon, include endoleaks, renal artery, and limb thrombosis.² This report emphasizes the importance of vigilance in terms of early recognition of unusual complications after EVAS and describes the successful management of type B aortic dissection after EVAS, which is a novel complication of EVAS not previously described.

METHOD

We describe a rare case of type B aortic dissection after EVAS and discuss the possible causes.

RESULT

After diagnosis of progressive type B aortic dissection after EVAS, patient underwent emergency thoracic endovascular aortic repair with carotid to subclavian bypass for the aortic dissection with good results. He was discharged well with return to his baseline function.

CONCLUSIONS

Aortic dissection is a potentially catastrophic complication of EVAS and with prompt recognition and monitoring, adverse complications may be averted.

Postoperative care in patients with DeBakey type I aortic dissection: criteria of aortic remodeling and risk factors of disease progression

AIM

To present current treatment modes for DeBakey type I aortic dissection, to compare their early and mid-term postoperative results, to evaluate predictors of negative aortic remodeling after surgery.

MATERIAL AND METHODS

Retrospective cohort analysis included 78 patients with DeBakey type I aortic dissection who underwent surgical treatment in 2009-2017. Patients were divided into 3 groups depending on type of intervention: group I (n=22) - Elephant Trunk procedure, group II (n=29) - hybrid interventions, group III (n=27) - proximal aortic replacement alone. Early postoperative results and aortic remodeling in mid-term postoperative period were compared.

RESULTS

There were no significant differences in postoperative morbidity, in-hospital mortality and freedom from aortic death. However, 7 patients were lost for follow-up in group III. Analysis of false lumen patency showed results in favor of more aggressive approach (groups I and II) with significantly higher rate of false lumen thrombosis in segments 1 and 2 (p<0,001 and p=0,004 respectively). Freedom from negative aortic remodeling was also significantly higher in groups I and II. Risk factors of patent false lumen were residual fenestration, large volume of false lumen in segment 2, dissection of supra-aortic vessels and connective tissue disorders. Risk factors of negative aortic remodeling were connective tissue disorders, patent false lumen and dissection of supra-aortic vessels.

CONCLUSION

Advanced surgical approach (Elephant Trunk procedure or hybrid interventions) should be preferred for DeBakey type I aortic dissection.

Biomechanical characterization and comparison of different aortic root surgical techniques

OBJECTIVES

Understanding the biomechanical impact of aortic valve-sparing techniques is important in an era in which surgical techniques are developing and are increasingly being used based on biomechanical understanding that is essential in the refining of existing techniques. The objective of this study was to describe how the valve-sparing remodelling (Yacoub) and reimplantation (David Type-1) techniques affect the biomechanics of the native aortic root in terms of force distribution and geometrical changes.

METHODS

Two force transducers were implanted into 22 pigs, randomized to 1 of 3 groups (David = 7, native = 7 and Yacoub = 8) along with 11 sonomicrometry crystals and 2 pressure catheters. Force and geometry data were combined to obtain the local structural stiffness in different segments of the aortic root.

RESULTS

The radial structural stiffness was not different between groups (P = 0.064) at the annular level; however, the David technique seemed to stabilize the aortic annulus more than the Yacoub technique. In the sinotubular junction, the native group was more compliant (P = 0.036) with the right-left coronary segment than the intervention groups. Overall, the native aortic root appeared to be more dynamic at both the annular level and the sinotubular junction than both intervention groups.

CONCLUSIONS

In conclusion, the David procedure may stabilize the aortic annulus more than the Yacoub procedure, whereas the leaflet opening area was larger in the latter (P = 0.030). No difference (P = 0.309) was found in valve-opening delay between groups. The 2 interventions show similar characteristics at the sinotubular junction, whereas the David technique seemed more restrictive at the annular level than the Yacoub technique.

Balloon protection of the left subclavian artery in debranching thoracic endovascular aortic repair

OBJECTIVES

Since 2012, we have routinely applied balloon protection of the proximal left subclavian artery to prevent embolic events through the left vertebral artery during debranching thoracic endovascular aortic repair. This study aimed to study the effectiveness of balloon protection of the proximal left subclavian artery.

METHODS

We reviewed the medical records of 157 patients who underwent debranching thoracic endovascular aortic repair between 2007 and 2017. Of these, 71 patients for whom balloon protection of the proximal left subclavian artery was used were assigned to the balloon protection of the proximal left subclavian artery group (58 men; age: 78 ± 6.7 years), and 86 patients were assigned to the control group (66 men; age: 78 ± 8.9 years). A total of 51 patients from each group were matched by their propensity scores to adjust for differences in the patients' characteristics.

RESULTS

Perioperative stroke was significantly lower in the balloon protection of the proximal left subclavian artery group than in the control group (0%: 0/71 vs 7.9%: 7/86, P = .014). Freedom from all causes of mortality at 2 and 4 years was significantly higher in the balloon protection of the proximal left subclavian artery group compared with the control group (93%/76% vs 77%/59%, P = .015). Freedom from aortic death at 2 and 4 years was similar in both groups (97%/97% vs 91%/86%, P = .094). Propensity score matching yielded similar results of better freedom from all causes of mortality in the balloon protection of the proximal left subclavian artery group (93%/93% vs 81%/63%, P = .017) and equivalent aortic death in both groups (95%/95% vs 92%/88%, P = .30).

CONCLUSIONS

Debranching thoracic endovascular aortic repair using balloon protection of the proximal left subclavian artery demonstrated more appropriate early and late outcomes. Evaluation using propensity score matching enhanced the efficacy of balloon protection of the proximal left subclavian artery.

New Conception of Relining in the Endovascular Aneurysm Sealing Era: A Monocentric Case Series Study

Over 20 years from the first endovascular aortic repair, endoleaks still represent a common problem, even with newer endograft generation. Numerous procedures can be adopted to manage these complications; relining of the endoprosthesis is a rational technique to treat type III and IV endoleaks. The absence of dedicated materials for these procedures forces the vascular surgeon to perform complex hybrid or endovascular interventions. In this case report, we aimed to evaluate our relining experience using the Nellix device in 5 consecutive cases.

Midterm Results of 2-Stage Hybrid Arch Repair for Extensive Aortic Arch Aneurysms

BACKGROUND

This report evaluated the perioperative and midterm results of the 2-stage hybrid arch procedure. This procedure involves total arch replacement with an elephant trunk as the first stage and thoracic endovascular aortic repair as the second stage for patients with extended aortic arch pathology.

METHODS

Between April 2010 and April 2017, 55 consecutive patients (age, 74.2 ± 6.4 years) with extended aortic arch atherosclerotic pathology involving the aortic arch and descending aorta underwent first-stage total arch replacement with the elephant trunk procedure. The second stage was completed for 53 (96.4%) of the 55 patients. The mean duration between the 2 procedures was 2.4 ± 2.2 months. Postoperative follow-up was completed after a mean of 36.6 ± 24.9 months.

RESULTS

The in-hospital mortality rate for the first stage was 0%. Two patients died during the interval between surgeries. The in-hospital mortality rate for the second stage was 0%. Two (3.6%) of the 55 first-stage patients and none of the 53 second-stage patients experienced a postoperative stroke. No spinal cord dysfunction occurred during the first-stage and second-stage procedures. The 3- and 5-year survival rates were 88.2% and 67.0%, respectively. The 5-year thoracic aortic intervention-free rate was 95.5%.

CONCLUSIONS

Extended aortic arch aneurysms were repaired using a 2-stage hybrid arch repair. Perioperative mortality and midterm results were acceptable. Use of an elephant trunk provided a secure landing zone for thoracic endovascular aneurysm repair. This 2-stage hybrid procedure is an alternative approach to extended aortic arch pathology.

Absence of LTBP-3 attenuates the aneurysmal phenotype but not spinal effects on the aorta in Marfan syndrome

Fibrillin-1 is an elastin-associated glycoprotein that contributes to the long-term fatigue resistance of elastic fibers as well as to the bioavailability of transforming growth factor-beta (TGFβ) in arteries. Altered TGFβ bioavailability and/or signaling have been implicated in aneurysm development in Marfan syndrome (MFS), a multi-system condition resulting from mutations to the gene that encodes fibrillin-1. We recently showed that the absence of the latent transforming growth factor-beta binding protein-3 (LTBP-3) in fibrillin-1-deficient mice attenuates the fragmentation of elastic fibers and focal dilatations that are characteristic of aortic root aneurysms in MFS mice, at least to 12 weeks of age. Here, we show further that the absence of LTBP-3 in this MFS mouse model improves the circumferential mechanical properties of the thoracic aorta, which appears to be fundamental in preventing or significantly delaying aneurysm development. Yet, a spinal deformity either remains or is exacerbated in the absence of LTBP-3 and seems to adversely affect the axial mechanical properties of the thoracic aorta, thus decreasing overall vascular function despite the absence of aneurysmal dilatation. Importantly, because of the smaller size of mice lacking LTBP-3, allometric scaling facilitates proper interpretation of aortic dimensions and thus the clinical phenotype. While this study demonstrates that LTBP-3/TGFβ directly affects the biomechanical function of the thoracic aorta, it highlights that spinal deformities in MFS might indirectly and adversely affect the overall aortic phenotype. There is a need, therefore, to consider together the vascular and skeletal effects in this syndromic disease.

Machine learning-aided exploration of relationship between strength and elastic properties in ascending thoracic aneurysm

Machine learning was applied to classify tension-strain curves harvested from inflation tests on ascending thoracic aneurysm samples. The curves were classified into rupture and nonrupture groups using prerupture response features. Two groups of features were used as the basis for classification. The first was the constitutive parameters fitted from the tension-strain data, and the second was geometric parameters extracted from the tension-strain curve. Based on the importance scores provided by the machine learning, implications of some features were interrogated. It was found that (1) the value of a constitutive parameter is nearly the same for all members in the rupture group and (2) the strength correlates strongly with a tension in the early phase of response as well as with the end stiffness. The study suggests that the strength, which is not available without rupturing the tissue, may be indirectly inferred from prerupture response features.

Aortic flow patterns and wall shear stress maps by 4D-flow cardiovascular magnetic resonance in the assessment of aortic dilatation in bicuspid aortic valve disease

BACKGROUND

In patients with bicuspid valve (BAV), ascending aorta (AAo) dilatation may be caused by altered flow patterns and wall shear stress (WSS). These differences may explain different aortic dilatation morphotypes. Using 4D-flow cardiovascular magnetic resonance (CMR), we aimed to analyze differences in flow patterns and regional axial and circumferential WSS maps between BAV phenotypes and their correlation with ascending aorta dilatation morphotype.

METHODS

One hundred and one BAV patients (aortic diameter ≤ 45 mm, no severe valvular disease) and 20 healthy subjects were studied by 4D-flow CMR. Peak velocity, flow jet angle, flow displacement, in-plane rotational flow (IRF) and systolic flow reversal ratio (SFRR) were assessed at different levels of the AAo. Peak-systolic axial and circumferential regional WSS maps were also estimated. Unadjusted and multivariable adjusted linear regression analyses were used to identify independent correlates of aortic root or ascending dilatation. Age, sex, valve morphotype, body surface area, flow derived variables and WSS components were included in the multivariable models.

RESULTS

The AAo was non-dilated in 24 BAV patients and dilated in 77 (root morphotype in 11 and ascending in 66). BAV phenotype was right-left (RL-) in 78 patients and right-non-coronary (RN-) in 23. Both BAV phenotypes presented different outflow jet direction and velocity profiles that matched the location of maximum systolic axial WSS. RL-BAV velocity profiles and maximum axial WSS were homogeneously distributed right-anteriorly, however, RN-BAV showed higher variable profiles with a main proximal-posterior distribution shifting anteriorly at mid-distal AAo. Compared to controls, BAV patients presented similar WSS magnitude at proximal, mid and distal AAo (p = 0.764, 0.516 and 0.053, respectively) but lower axial and higher circumferential WSS components (p < 0.001 for both, at all aortic levels). Among BAV patients, RN-BAV presented higher IRF at all levels (p = 0.024 proximal, 0.046 mid and 0.002 distal AAo) and higher circumferential WSS at mid and distal AAo (p = 0.038 and 0.046, respectively) than RL-BAV. However, axial WSS was higher in RL-BAV compared to RN-BAV at proximal and mid AAo (p = 0.046, 0.019, respectively). Displacement and axial WSS were independently associated with the root-morphotype, and circumferential WSS and SFRR with the ascending-morphotype.

CONCLUSIONS

Different BAV-phenotypes present different flow patterns with an anterior distribution in RL-BAV, whereas, RN-BAV patients present a predominant posterior outflow jet at the sinotubular junction that shifts to anterior or right anterior in mid and distal AAo. Thus, RL-BAV patients present a higher axial WSS at the aortic root while RN-BAV present a higher circumferential WSS in mid and distal AAo. These results may explain different AAo dilatation morphotypes in the BAV population.

Experimental evaluation of homemade distal stent graft fenestration for thoracic endovascular aortic repair of type A dissection by a transapical approach

OBJECTIVE

The use of off-the-shelf stent grafts for thoracic endovascular aortic repair of type A dissections is limited by variability in both the length of the ascending aorta and the location of the proximal intimal tear. This experimental study aimed to assess the feasibility of using a physician-modified thoracic aortic stent graft to treat acute type A dissection by a transapical cardiac approach.

METHODS

The experiments were performed on six cadaveric human heart, ascending aorta, aortic arch, and descending aorta specimens. Fenestration was fashioned in each standard tubular Valiant thoracic stent graft (Valiant Captivia; Medtronic Vascular, Santa Rosa, Calif) to match the anatomy of each specimen. Stent grafts of sufficient length were selected to cover the entire ascending aorta and aortic arch. Stent graft diameters in proximal sealing zones were oversized by 5% to 10%. The length of the fenestration was the distance between the left subclavian artery and the proximal edge of the origin of the brachiocephalic trunk with an additional 10 mm. The diameter of the scallop was that of the brachiocephalic trunk with an additional 5 mm on all sides. The length of the covered portion of the stent graft was the distance between coronary arteries and the proximal edge of the origin of the brachiocephalic trunk. Two lateral radiopaque markers were positioned to delineate the distal and lateral edge of the scallop. Another 3-cm radiopaque marker was sutured onto the sheath to ensure accurate radiologic positioning of the scallop on the outer curve of the aorta. The left ventricle and the thoracic aorta were connected to a benchtop aortic pulsatile flow model. A 5-mm 30-degree lens was introduced through the left subclavian artery to monitor the procedure. The customized stent graft was deployed by a transapical approach under fluoroscopic control.

RESULTS

Median duration of stent graft modification was 21 minutes (range, 17-40 minutes). All attempts to deploy the homemade proximal scalloped stent graft by a transapical approach were successful. Completion angiography demonstrated patency of the supra-aortic trunks and of the coronary arteries in all cases. Macroscopic evaluation did not identify any deterioration of the customized stent graft.

CONCLUSIONS

The use of physician-modified stent grafts is feasible for thoracic endovascular aortic repair of type A dissection by a transapical approach in this model.

Suppressive effect of pitavastatin on aortic arch dilatation in acute stanford type B aortic dissection: analysis of STANP trial

OBJECTIVES

Medical therapy for patients with uncomplicated acute type B aortic dissection (ABAD) is essentially accepted for its excellent early outcome; however, long-term outcomes have not been satisfactory due to aorta-related complications. This trial was performed to investigate the efficacy of a statin as an additive that may enhance the effectiveness of conventional medical treatment in patients with ABAD.

METHODS

This was a multi-center, prospective, and randomized comparative investigation of patients with uncomplicated ABAD. Fifty patients with ABAD compatible with inclusion criteria were randomly assigned to two groups and then received administration of pitavastatin (group P) or not (group C). We followed up the patients for 1 year from study onset.

RESULTS

Two patients demised during the follow-up period (both were in group C). In addition, aorta-related interventions were performed in two patients (entry closure for aortic dissection by endovascular repair in one patient in each group). Aortic arch diameters at 1 year in group P tended to be smaller than in group C (P = 0.17), and the rate of change of the aortic arch diameters from onset to 1 year was significantly lower in group P (P = 0.046). Multivariate analysis identified patency of the false lumen was detected as a risk factor for aortic arch dilatation (P = 0.02), and pitavastatin intake was a negative risk factor (P = 0.03).

CONCLUSIONS

Pitavastatin treatment, in addition to the standard antihypertensive therapy, may have a suppressive effect on aortic arch dilatation in patients with ABAD.

Laser Fenestration for Treatment of a Complicated Chronic Type B Aortic Dissection

We report a case of a complex chronic type B aortic dissection treated by thoracic endovascular aortic repair and laser fenestration of the false septum to preserve flow to branch vessels originating from both the true and false lumen. Dissections complicated by thoracoabdominal aneurysmal degeneration with critical organs being perfused by branches arising from both true and false lumens are rare and leave limited options for repair. Despite advancements in endovascular techniques, fenestration remains one of the only means of preserving flow to both the true and false lumens and thus was necessary in the management of our patient. This novel procedure allows complex aortic dissections to be addressed endovascularly, which increases the flexibility and management of this challenging problem that previously required an open repair with significant morbidity.

Wall stress on ascending thoracic aortic aneurysms with bicuspid compared with tricuspid aortic valve

OBJECTIVE

Guidelines for repair of bicuspid aortic valve-associated ascending thoracic aortic aneurysms have been changing, most recently to the same criteria as tricuspid aortic valve-ascending thoracic aortic aneurysms. Rupture/dissection occurs when wall stress exceeds wall strength. Recent studies suggest similar strength of bicuspid aortic valve versus tricuspid aortic valve-ascending thoracic aortic aneurysms; thus, comparative wall stress may better predict dissection in bicuspid aortic valve versus tricuspid aortic valve-ascending thoracic aortic aneurysms. Our aim was to determine whether bicuspid aortic valve-ascending thoracic aortic aneurysms had higher wall stresses than their tricuspid aortic valve counterparts.

METHODS

Patients with bicuspid aortic valve- and tricuspid aortic valve-ascending thoracic aortic aneurysms (bicuspid aortic valve = 17, tricuspid aortic valve = 19) greater than 4.5 cm underwent electrocardiogram-gated computed tomography angiography. Patient-specific 3-dimensional geometry was reconstructed and loaded to systemic pressure after accounting for prestress geometry. Finite element analyses were performed using the LS-DYNA solver (LSTC Inc, Livermore, Calif) with user-defined fiber-embedded material model to determine ascending thoracic aortic aneurysm wall stress.

RESULTS

Bicuspid aortic valve-ascending thoracic aortic aneurysms 99th-percentile longitudinal stresses were 280 kPa versus 242 kPa (P = .028) for tricuspid aortic valve-ascending thoracic aortic aneurysms in systole. These stresses did not correlate to diameter for bicuspid aortic valve-ascending thoracic aortic aneurysms (r = -0.004) but had better correlation to tricuspid aortic valve-ascending thoracic aortic aneurysms diameter (r = 0.677). Longitudinal stresses on sinotubular junction were significantly higher in bicuspid aortic valve-ascending thoracic aortic aneurysms than in tricuspid aortic valve-ascending thoracic aortic aneurysms (405 vs 329 kPa, P = .023). Bicuspid aortic valve-ascending thoracic aortic aneurysm 99th-percentile circumferential stresses were 548 kPa versus 462 kPa (P = .033) for tricuspid aortic valve-ascending thoracic aortic aneurysms, which also did not correlate to bicuspid aortic valve-ascending thoracic aortic aneurysm diameter (r = 0.007).

CONCLUSIONS

Circumferential and longitudinal stresses were greater in bicuspid aortic valve- than tricuspid aortic valve-ascending thoracic aortic aneurysms and were more pronounced in the sinotubular junction. Peak wall stress did not correlate with bicuspid aortic valve-ascending thoracic aortic aneurysm diameter, suggesting diameter alone in this population may be a poor predictor of dissection risk. Our results highlight the need for patient-specific aneurysm wall stress analysis for accurate dissection risk prediction.

[Treatment of an aortic arch aneurysm ruptured into the lung]

Described herein is a clinical case report concerning treatment of a 32-year-old female patient with rupture of an aneurysm of the arch and descending portion of the thoracic aorta, with the bleeding having penetrated the upper lobe of the left lung. The woman was admitted to the Department of Vascular Surgery of Municipal Multimodality Hospital No 2 of Saint Petersburg, presenting with a clinical pattern of aneurysmal rupture previously diagnosed by computed tomography performed at one of the local hospitals. Studying her case history revealed that, when a child, she had endured an operation for a defect of the interventricular septum and aortic coarctation with aortoplasty using a Dacron synthetic patch. On admission, she was treated as an emergency to immediately undergo temporal ascending-descending bypass grafting of the aorta and left common carotid artery without use of a heart-lung machine. After resection of the aneurysm of the arch and descending portion of the thoracic aorta and removal of the upper lobe of the left lung, a decision was made to leave the temporal shunt as permanent. In the early postoperative period the woman developed acute cerebral circulation impairment with minimal neurological deficit which was later on relieved. After 22 days, due to persisting atelectasis of the lower lobe of the left lung, the presence of an incompetent stump of the upper bronchus and air in the left pleural cavity, as well as high risk of infection of the vascular graft, we performed final bilateral pneumonectomy with omentopexy, i. e., suturing of the greater omentum to a portion of the thoracic graft. The woman was discharged on postoperative day 34 in a satisfactory condition. She then successfully gave birth to a child. She is currently presenting neither complaints nor evidence of respiratory insufficiency. The duration of follow up amounted to 8 years.

[Mycotic aneurysms: a case report, clinical review, imaging appearances and management]

To report a clinical case of mycotic thoracic aortic aneurysm. To describe and illustrate the spectrum of MDCT findings, analysing the pathophysiology, diagnostic evaluation and therapeutic management. To emphasis the early non-invasive diagnosis as a way to overall survival improvement. A mycotic aneurysm is an uncommon vascular lesion resulting from arterial wall destruction by infection, generally involving the peripheral arteries or aorta and rarely the cerebral and visceral arteries. Defined as a lobulated saccular outpouching of the wall communicating with the lumen, it is surrounded by oedema, hematoma and/or fibro-inflammatory tissue. Due the non-specific and delayed - or even absent - manifestations, a high degree of clinical suspicion is necessary to achieve a timely treatment and prognosis improvement. In this setting, radiologic evaluation - mainly by MDCT angiography - is essential, allowing detection, characterization and complications assessment before treatment planning.

[Hybrid intervention for a ruptured thoracoabdominal aortic aneurysm]

A ruptured thoracoabdominal aortic aneurysm is an urgent situation requiring emergency surgery during which it is necessary to decrease the scope of the intervention in a patient at an extremely high surgical risk. A combination of surgical and endovascular techniques makes it possible to minimize surgical injury, blood loss, to shorten the duration of internal organs ischaemia, to reduce the risk of paraplegia. Presented herein are the results of emergency hybrid intervention for a ruptured thoracoabdominal aortic aneurysm, accompanied and followed by description of the technical aspects of performing the surgical and endovascular stages. The early postoperative period was complicated by thrombosis of the left superficial femoral artery on the background of atherosclerotic lesions, which was successfully eliminated by means of endovascular intervention with endovascular prosthetic repair. After 10 months, the patient underwent a cardiosurgical intervention. Combining surgical and endovascular techniques made it possible in an emergency situation to save the patient's life and to provide its good quality in the remote period of follow up (4 years after the hybrid operation).

[Hybrid approach to treatment of a patient with a thoracoabdominal aortic aneurysm]

Described in the article is a clinical case report concerning staged management of a patient presenting with a thoracoabdominal aortic aneurysm. The first stage consisted in complete lower debranching with prosthetic repair of all visceral arteries and the right renal artery. The second stage was endovascular repair of the aortic aneurysm. The chosen approach made it possible to avoid clamping of the thoracic portion of the aorta, which favourably contributed to a decrease in the traumatic nature of the operative procedure, simultaneously preserving the radicality of treatment after the two-stage intervention.

Endovascular Repair of Interrupted Aortic Arch: Approach with Hope for Fewer Complications

Interrupted aortic arch (IAA) is a rare congenital malformation defined as complete discontinuity between ascending and descending parts of aorta. We present a case of IAA, which was referred to us due to dilatation of proximal and mid parts of his thoracic aorta accompanied by narrowing of aorta proximal to the branching of the left subclavian artery. Further evaluation revealed interruption of aorta at the proximal part of descending thoracic aorta by a transverse septum along with several collateral formations. In general, the standard treatment of IAA is open surgical repair. Endovascular repair of IAA is an alternative approach for IAA, which is applied when two distinct parts of aorta are too close to each other. Here, we present a new approach of endovascular transcatheter repair of IAA with implantation of a self-expandable stent that we believe has fewer complications.

Bentall’s Procedure in Pediatric Mixed Connective Tissue Disease Syndrome: Management of Pediatric Aortic Aneurysm - A Brief Review

Mixed connective tissue disease (MCTD) syndrome in children may lead to large aortic aneurysms, which in turn pose a difficult surgical problem. Valve-sparing root replacement is not always a viable option as the disease process invariably affects the aortic valve leaflets. Among pediatric patients, the Ross procedure is contraindicated on account of weakness of the pulmonary root, while Bentall surgery is the 'gold standard' treatment of aortic aneurysm, with reproducible and excellent long-term results. The case is presented of a three-year-old girl with a large thoracic aortic aneurysm in whom Bentall's surgery was performed, with a good result. The present patient, with MCTD syndrome, was too young to have undergone aortic root replacement with a composite mechanical valved graft.

Hemodynamic assessments of the ascending thoracic aortic aneurysm using fluid-structure interaction approach

Current assessment and management of ascending thoracic aortic aneurysm (ATAA) rely heavily on the diameter of the ATAA and blood pressure rather than biomechanical and hemodynamic parameters such as arterial wall deformation or wall shear stress. The objective of the current study was to develop an accurate computational method for modeling the mechanical responses of the ATAA to provide additional information in patient evaluations. Fully coupled fluid structure interaction simulations were conducted using data from cases with ATAA with measured geometrical parameters in order to evaluate and analyze the change in biomechanical responses under normotensive and hypertensive conditions. Anisotropic hyperelastic material property estimates were applied to the ATAA data which represented three different geometrical configurations of ATAAs. The resulting analysis showed significant variations in maximum wall shear stress despite minimal differences in flow velocity between two blood pressure conditions. Additionally, the three different ATAA conditions identified different aortic expansions that were not uniform under pulsatile pressure. The elevated wall stress with hypertension was also geometry-dependent. The developed models suggest that ATTA cases have unique characteristic in biomechanical and hemodynamic evaluations that can be useful in risk management.