Comparison of chimney technique and single-branched stent graft in a cohort of patients with type B aortic dissections: a retrospective cohort study.

Background: Single-branched stent grafts and the chimney technique are widely used in the treatment of type B aortic dissection (TBAD). The main objective of this study was to compare the outcomes of single-branched stent grafts and the chimney technique in the treatment of TBAD. Methods: From January 2019 to December 2021, the retrospective cohort study contained a cohort of 91 patients with TBAD undergoing thoracic endovascular aortic repair (TEVAR) using single-branched stent grafts and the chimney technique. Group A included 55 patients treated with single-branched covered stents, and Group B included 36 patients treated with the chimney technique. We compared the effects of the procedures on peri-/post-operative outcomes between the two groups. The primary endpoint is clinical death, and the secondary endpoints include the patency of branch stents, the incidence of cerebral infarction, false lumen thrombosis, and the proportion of paraplegia. Results: For the baseline data, the two groups of patients show no differences in terms of age, gender, and associated symptoms. All procedures were successfully performed in both groups. The median follow-up period was 17.6 months (range, 10-34 months). During TEVAR, 5 (9.1%) type I endoleaks occurred in group A, and 11 (30.6%) occurred in group B (P<0.05). During follow-up, there were 2 cases (3.6%) of paraplegia and 1 case (1.8%) of cerebral infarction in Group A, while Group B had 1 case (2.8%) of paraplegia. Three patients in group B reported retrograde type A aortic dissection (RTAD), and 1 of them died (2.8%); however, there were no RTAD cases in group A. Complete thrombosis of the false lumen in the thoracic aorta was observed in 45.5% (25/55) of patients in group A and in 41.7% (15/36) in group B (P=0.72). No significant difference in the thrombosis-volume ratio in the whole false lumen was found during follow-up between group A (81.0%±2.9%) and group B (81.8%±2.6%; P=0.23). Conclusions: Branched stent grafts can be used in cases with insufficient proximal landing zones and reduce the occurrence of type 1 endoleak compared to the chimney technique. This may help to prevent RTAD. Further research, including more cases and longer follow-up periods, is needed to substantiate these results.

Five-year outcomes of endovascular treatment for aortic dissection from the Global Registry for Endovascular Aortic Treatment.

OBJECTIVE: The Global Registry for Endovascular Aortic Treatment (GREAT) is an International prospective multicenter registry collecting real-world data on performance of Gore aortic endografts. The purpose was to analyze the long-term outcomes and patient survival rates, as well as device performance in patients undergoing thoracic endovascular aortic repair for acute and chronic and complicated or uncomplicated type B aortic dissection (TBAD). METHODS: From August 2010 to October 2016, 5014 patients were enrolled in the GREAT registry. The study population were patients treated with thoracic endovascular aortic repair for TBAD through 5-year follow-up (days 0-2006). The primary outcomes for this analysis were all-cause and aortic-related mortality, stroke, aortic rupture, endoleaks, migration, fracture, compression, and any reintervention through 5 years. RESULTS: We identified 265 patients. The mean age was 60.9 ± 11.9 years (range, 19-84 years; 211 males [79.6%]). Devices used were the Gore TAG and Conformable Gore TAG Thoracic Endoprosthesis. There were 228 patients (86.0%) who underwent primary endovascular treatment (144 off-label [54.3%]); 22 (8.3%) underwent reintervention after prior endovascular procedure and 15 (5.7%) underwent reintervention after prior open procedure. Kaplan-Meier estimated freedom from all-cause mortality at 5 years was 71.1%. Freedom from aortic-related mortality through 5 years was 95.8%. There was no significant difference in freedom from all-cause mortality during the follow-up period in complicated or uncomplicated disease. At 30 days and through 5 years, respectively, for all the following outcomes, the aortic rupture rate was 1.1% (n = 3) and 1.9% (n = 5). The stroke rate was 1.1% (n = 3) and 4.2% (n = 11). The spinal cord ischemic event rate was 1.5% (n = 4) and 2.6% (n = 7). Reinterventions were required in 6.4% (n = 17) and 21.1% (n = 56) of patients. The need for conversion to open repair was 0.4% (n = 1) and 2.6% (n = 7). Additional graft placement was required in 3 patients (1.1%) and 16 patients (6.0%). The endoleak rate at 30 days was 3.4% (n = 9); type IA (n = 1 [0.4%]), type IB (n = 4 [1.5%]), type II (n = 1 [0.4%]), type III (n = 1 [0.4%]), and unspecified (n = 4 [1.6%]). Through 5 years, the endoleak rate was 12.1% (n = 32); type IA (n = 7 [2.6%]), type IB (n = 10 [3.8%]), type II (n = 9 [3.4%]), type III (n = 2 [0.8%]), and unspecified (n = 12 [4.5%]). There were no cases of stent migration, compression or fracture through 5 years. CONCLUSIONS: Results at the 5-year follow-up demonstrate that the use of the Gore TAG and Conformable Gore TAG Thoracic Endoprosthesis can be supported in treatment of TBAD (acute, chronic, complicated, and uncomplicated). These data demonstrate strong device durability, beneficial patient outcomes, and support for the treatment of thoracic aortic dissection with an endovascular approach. Complete 10-year follow-up in GREAT as planned will be advantageous.

Spinal cord ischemia and reinterventions following thoracic endovascular repair for acute type B aortic dissections.

OBJECTIVE: The technical aspects of thoracic endovascular aortic repair (TEVAR) for acute type B aortic dissection (TBAD), specifically the location of proximal seal zone (PSZ) (need to cover the left subclavian artery [LSA]), distal seal zone (DSZ) (length of aortic coverage), benefit of LSA revascularization, and prophylactic lumbar drainage are still debated. Each of these issues has potential benefits but also has known risks. This study aims to identify factors associated with reintervention and spinal cord ischemia (SCI) following TEVAR for acute TBAD with a zone 3 entry tear. METHODS: The Vascular Quality Initiative was queried for TEVARs performed for acute TBAD with zone 3 entry tear, zone 3 proximal zone of disease, treated with TEVAR extending between zone 2 and zone 5. The primary outcomes were SCI and related reintervention. Secondary outcomes were stroke, arm ischemia, and retrograde type A dissection (RTAD). The exposure variables were PSZ 2 vs 3, DSZ 4 vs 5, prophylactic lumbar drain, and LSA revascularization. Univariate analyses were conducted with χ2 analysis, and multivariable logistic regression was used to evaluate association with outcomes. RESULTS: Of 583 patients who met inclusion criteria, 266 had PSZ 2 and 317 had PSZ 3. On univariate analysis, PSZ 2 was associated with a higher rate of reintervention, but PSZ2 was not significant on multivariable analysis after accounting for age, sex, race, smoking, PSZ, DSZ, prophylactic lumbar drain, and LSA patency. PSZ 2 was not associated with SCI, arm ischemia, or RTAD. PSZ 2 was associated with a trend towards a higher rate of stroke. DSZ 4 and DSZ 5 were performed in 161 and 422 TEVARs, respectively, and DSZ 5 was associated with a higher rate of SCI on univariate (3 [1.9%] vs 39 [9.2%]; P = .01) and multivariable (odds ratio, 7.384; 95% confidence interval, 2.193-24.867; P = .001) analyses. Prophylactic lumbar drain placement was not statistically significantly associated with SCI, but lack of postoperative LSA patency was associated with SCI (odds ratio, 2.966; 95% confidence interval, 1.016-8.656; P = .05). CONCLUSIONS: This study found that PSZ 2 was not associated with lower reinterventions or higher rates of SCI but trended towards a higher rate of stroke than PSZ 3. Additionally, DSZ 5 was strongly associated with SCI when compared with DSZ 4, highlighting the importance of limiting aortic coverage to coverage of the proximal entry tear when possible.

Triglyceride-glucose index and triglyceride to high-density lipoprotein cholesterol ratio predict the prognosis in patients with type B aortic dissection receiving thoracic endovascular aortic repair.

Background: The triglyceride-glucose (TyG) index and triglyceride to high-density lipoprotein cholesterol (TG/HDL-c) ratio are both reliable surrogate indicator of insulin resistance and have been shown to be valuable in predicting various cardiovascular diseases. However, few studies have explored its association with the prognosis of type B aortic dissection (TBAD) patients receiving thoracic endovascular aortic repair (TEVAR). Methods: A total of 1,425 consecutive patients who underwent TEVAR were included. Data from 935 patients were analyzed in the study. The endpoint was defined as 30-day and 1-year aortic-related adverse events (ARAEs), all-cause mortality, and major adverse cardiovascular and cerebrovascular events (MACCEs). Results: There were 935 patients included during a mean follow-up time of 2.8 years. After adjusting for multiple confounding factors, continuous TG/HDL-c [hazard ratio (HR) =1.07; 95% confidence interval (CI): 1.00-1.15; P=0.041] was independently associated with 1-year all-cause mortality. Both a high (Quintile 5: TG/HDL-c ratio ≥4.11) (HR =4.84; 95% CI: 1.55-15.13; P=0.007) and low TG/HDL-c ratio (Quintile 1: TG/HDL-c ratio <1.44) (HR =4.67; 95% CI: 1.46-14.94; P=0.001) were still independent risk factors for 1-year all-cause mortality. Conclusions: Elevated baseline TG/HDL-c ratio and TG/HDL-c ≥4.11 were significantly related to a higher risk of 1-year all-cause mortality among TBAD patients undergoing TEVAR. At the same time, the low TG/HDL-c ratio was also independently associated with 1-year all-cause mortality. Special attention should be paid to TBAD patients with a higher or an overly low TG/HDL-c ratio.

Entry tear hemodynamics using 4D flow MRI in a patient with acute type B aortic dissection.

Stanford type B aortic dissection (TBAD) is a potentially fatal condition involving a tear in the descending aorta. As TBAD can be managed with medical therapy or surgical repair, identifying predictors of adverse outcomes is important to risk-stratify patients for preemptive surgical procedures. 4D flow magnetic resonance imaging (MRI) has shown to be useful in characterizing the complex hemodynamics seen in TBAD patients and correlating flow patterns with adverse outcomes. We report a case of a 58-year-old man who presented to the hospital with acute TBAD and a large primary entry tear. He was initially managed with medical therapy due to his stable clinical status and computed tomographic angiography showing a stable dissection. However, 4D flow MRI showed high velocity flow through the entry tear, which foreshadowed the later clinical decompensation of the patient. Our case demonstrates that performing 4D flow MRI on TBAD patients is feasible and can provide valuable information in the decision to pursue medical or surgical management.

Screening plasma metabolites as potential biomarkers for type B aortic dissection.

Background: Aortic dissection (AD) is a serious aortic disease. Although current imaging methods can provide accurate diagnosis for AD, they do not include essential biological information. The aim of this study is to identify plasma metabolites for the risk and severity of type B AD (TBAD). Methods: In this cross-sectional study, we enrolled 16 hypertensive patients with TBAD and 7 hypertensive patients without TBAD in Jieyang People's Hospital between December 2021 and April 2022. After plasma metabolomics analysis, a metabolites risk score (MRS) model was conducted through logistic regression and least absolute shrinkage and selection operator (LASSO) regression to predict the risk of TBAD. Subsequently, TBAD group was divided into uncomplicated and complicated TBAD subgroups for further screening for metabolites related to the severity of TBAD. Results: Three metabolites, including 1,5-anhydro-D-glucitol, D-(+)-sucrose and PC(O-16:0/0:0) were related to the risk of TBAD. Compared to hypertensive patients without TBAD, the abundance of 1,5-anhydro-D-glucitol and D-(+)-sucrose were significantly increased while PC(O-16:0/0:0) was significantly reduced in hypertensive patients with TBAD (P<0.001). We subsequently built an MRS model based on these three metabolites. Furthermore, we found that hydrocinnamic acid (r=0.741, P<0.001) was independently correlated with the TBAD severity, while glycine deoxycholic acid (r=-0.538, P=0.008) and glycochenodeoxycholic acid (r=-0.538, P=0.008) were inversely correlated with the TBAD severity independently. Conclusions: The present study screened out three plasma metabolites associated with the risk of TBAD, constructed an MRS model, and identified three metabolites that were independently associated with the severity of TBAD. These findings may serve to identify more TBAD-related biomarkers and shed light on exploring potential mechanisms of TBAD.

Changes in the renal artery and renal volume and predictors of renal atrophy in patients with complicated type B aortic dissection after thoracic endovascular aortic repair.

Background: For complicated Stanford type B aortic dissection (TBAD), thoracic endovascular aortic repair (TEVAR) is the recommended treatment; however, the type of renal artery that should be repaired remains controversial. The study aimed to investigate the changes in the renal artery and renal volume in complicated TBAD after TEVAR and the predictors of renal atrophy. Methods: The cohort study retrospectively enrolled patients with acute and subacute complicated TBAD who underwent aortic computed tomography angiography (CTA) 1 month before as well as 1 week and half a year after TEVAR from January 2010 to May 2017. According to the source of blood supply shown in preoperative CT, the renal artery was classified in 3 ways: type 1, supplied by the aortic true lumen; type 2, supplied by the aortic false lumen; or type 3, supplied by both the true and false lumen. Results: A total of 91 patients (81 men and 10 women) with an average age of 48.12±10.35 years were enrolled. Renal arteries were classified as type 1 (n=91), type 2 (n=35), and type 3 (n=56). There was no difference in the distribution of the 3 types on the left and right sides (type 1 vs. type 2 vs. type 3: 52:39 vs. 15:20 vs. 24:32; P=0.152). After TEVAR, type 3 was more likely to have spontaneous healing than type 2 (16.1% vs. 2.9%; P=0.049). There was no significant difference in the preoperative volume of kidneys of the 3 types (type 1 vs. type 2 vs. type 3: 198.23±38.68 vs. 197.37±41.77 vs. 195.10±36.11 mL; P=0.893). The postoperative volume of types 2 and 3 was smaller than that of type 1 (type 1 vs. type 2 vs. type 3: 190.09±43.25 vs. 165.15±52.63 vs. 170.70±45.28 mL; P=0.006). The renal volume was reduced in all 3 types of renal artery, especially in type 2 (the change of renal volume for type 1 vs. type 2 vs. type 3: -8.14±29.31 vs. -32.22±41.59 vs. -24.41±38.44 mL; P=0.001). The relative change of renal volume for type 1 vs. type 2 vs. type 3: (-3.64±15.69)% vs. (-16.00±21.29)% vs. (-11.97±18.22)%; P=0.001). During the median follow-up of 668 days, 7 patients (7.7%) belonging to types 2 and 3 developed renal atrophy. False lumen thrombosis in the abdominal aorta and/or the renal artery was the predictor of renal atrophy [hazard ratio (HR) =17.757; P=0.008]. Conclusions: Patients with type 2 or 3 renal artery and false lumen thrombosis in the abdominal aorta and/or renal artery should be monitored closely and actively intervened to prevent renal atrophy.

Nationwide database analysis of one-year readmission rates after open surgical or thoracic endovascular repair of Stanford Type B aortic dissection.

Objective: We examined readmissions and resource use during the first postoperative year in patients who underwent thoracic endovascular aortic repair or open surgical repair of Stanford type B aortic dissection. Methods: The Nationwide Readmissions Database (2016-2018) was queried for patients with type B aortic dissection who underwent thoracic endovascular aortic repair or open surgical repair. The primary outcome was readmission during the first postoperative year. Secondary outcomes included 30-day and 90-day readmission rates, in-hospital mortality, length of stay, and cost. A Cox proportional hazards model was used to determine risk factors for readmission. Results: During the study period, type B aortic dissection repair was performed in 6456 patients, of whom 3517 (54.5%) underwent thoracic endovascular aortic repair and 2939 (45.5%) underwent open surgical repair. Patients undergoing thoracic endovascular aortic repair were older (63 vs 59 years; P < .001) with fewer comorbidities (Elixhauser score of 11 vs 17; P < .001) than patients undergoing open surgical repair. Thoracic endovascular aortic repair was performed electively more often than open surgical repair (29% vs 20%; P < .001). In-hospital mortality was 9% overall and lower in the thoracic endovascular aortic repair cohort than in the open surgical repair cohort (5% vs 13%; P < .001). However, the 90-day readmission rate was comparable between the thoracic endovascular aortic repair and open surgical repair cohorts (28% vs 27%; P = .7). Freedom from readmission for up to 1 year was also similar between cohorts (P = .6). Independent predictors of 1-year readmission included length of stay more than 10 days (P = .005) and Elixhauser comorbidity risk index greater than 4 (P = .033). Conclusions: Approximately one-third of all patients with type B aortic dissection were readmitted within 90 days after aortic intervention. Surprisingly, readmission during the first postoperative year was similar in the open surgical repair and thoracic endovascular aortic repair cohorts, despite marked differences in preoperative patient characteristics and interventions.

Prediction of aortic dilatation in surgically repaired type A dissection: A longitudinal study using computational fluid dynamics.

Objective: To examine the role of a key hemodynamic parameter, namely the true and false lumen pressure difference, to predict progressive aortic dilatation following type A aortic dissection (TAAD) repair. Methods: Four patients with surgically repaired TAAD with multiple follow-up computed tomography angiography scans (4-5 scans per patient; N = 18) were included. Through-plane diameter of the residual native thoracic aorta was measured in various aortic segments during the follow up period (mean follow-up: 49.6 ± 31.2 months). Computational flow analysis was performed to estimate true and false lumen pressure difference at the same locations and the correlation with aortic size change was studied using a linear mixed effects model. Results: Greater pressure difference between the true and false lumen was consistent with greater aortic diameter expansion during the follow up period (linear mixed effects analysis; coefficient, 0.26; 95% confidence interval, 0.15-0.37; P < .001). Based on our limited data points, a pressure difference higher than 5 mm Hg might cause unstable aortic growth. Conclusions: Computational fluid dynamic assessment of standard aortic computed tomography angiography offers a noninvasive technique that predicts the risk of aortic dilatation following TAAD. The technique may be used to plan closer observation or intervention in high-risk patients.

The misnomer of uncomplicated type B aortic dissection.

BACKGROUND: Acute type B aortic dissection (TBAD) is a rare condition that can be divided into complicated (CoTBAD) and uncomplicated (UnCoTBAD) based on certain presenting clinical and radiological features, with UnCoTBAD constituting the majority of TBAD cases. The classification of TBAD directly affects the treatment pathway taken, however, there remains confusion as to exactly what differentiates complicated from uncomplicated TBAD. AIMS: The scope of this review is to delineate the literature defining the intervention parameters for UnCoTBAD. METHODS: A comprehensive literature search was conducted using multiple electronic databases including PubMed, Scopus, and EMBASE to collate and summarize all research evidence on intervention parameters and protocols for UnCoTBAD. RESULTS: A TBAD without evidence of malperfusion or rupture might be classified as uncomplicated but there remains a subgroup who might exhibit high-risk features. Two clinical features representative of "high risk" are refractory pain and persistent hypertension. First-line treatment for CoTBAD is TEVAR, and whilst this has also proven its safety and effectiveness in UnCoTBAD, it is still being managed conservatively. However, TBAD is a dynamic pathology and a significant proportion of UnCoTBADs can progress to become complicated, thus necessitating more complex intervention. While the "high-risk" UnCoTBAD do benefit the most from TEVAR, yet, the defining parameters are still debatable as this benefit can be extended to a wider UnCoTBAD population. CONCLUSION: Uncomplicated TBAD remains a misnomer as it is frequently representative of a complex ongoing disease process requiring very close monitoring in a critical care setting. A clear diagnostic pathway may improve decision making following a diagnosis of UnCoTBAD. Choice of treatment still predominantly depends on when an equilibrium might be reached where the risks of TEVAR outweigh the natural history of the dissection in both the short- and long-term.

Physician-Modified TEVAR versus Hybrid Repair of the Proximal Descending Thoracic Aorta.

There are different surgical options for the treatment of proximal lesions of the descending thoracic aorta. The aim of this study was to compare the outcome of physician-modified TEVAR (pmTEVAR) vs. hybrid repair of the thoracic aorta in terms of TEVAR with carotid-subclavian bypass (hdTEVAR). This was a single-centre, retrospective comparative study of all patients who underwent pmTEVAR and hybrid repair of the proximal descending aorta from January 2018 to June 2021. Primary outcomes were technical success, 30-day mortality, perioperative stroke, 30-day reinterventions and supraaortic access related complications. Secondary outcomes were patient survival, late complications, late reinterventions, and bypass/bridging stent patency. A total of 181 patients underwent TEVAR within the period of 42 months. In our study, only patients with proximal landing in zone 2 (n = 39) were included. A total of 5 of 15 pmTEVAR and 8 of 24 hybrid repair operations (33% vs. 33%, respectively) were performed due to aneurysms. Among the rest of the patients, 10 of 15 pmTEVAR and 16 of 24 hybrid operations (67% vs. 67%) were performed due to aortic dissection. Technical success was achieved in 100% of the patients. No significant difference in terms of postoperative complications could be detected in the early and midterm follow up period. The 30-day mortality was 12.5% in the hybrid repair group (n = 3) vs. 6.66% (n = 1) in the pmTEVAR group (p = 0.498). These patients underwent the operation in an emergency setting. No patient died after an elective operation. The causes of early mortality were major stroke (n = 2), haemorrhagic shock (n = 1) in the hybrid group and progredient spinal cord ischemia with tetraplegia and acute respiratory insufficiency (n = 1) in the pmTEVAR group. In conclusion, both therapies are robust techniques, with comparable patency rate and perioperative complications. pmTEVAR appears to be advantageous in terms of operation time and tendency to lower mortality rates.

Baseline 4D Flow-Derived in vivo Hemodynamic Parameters Stratify Descending Aortic Dissection Patients With Enlarging Aortas.

Purpose: The purpose of our study was to assess the value of true lumen and false lumen hemodynamics compared to aortic morphological measurements for predicting adverse-aorta related outcomes (AARO) and aortic growth in patients with type B aortic dissection (TBAD). Materials and Methods: Using an IRB approved protocol, we retrospectively identified patients with descending aorta (DAo) dissection at a large tertiary center. Inclusion criteria includes known TBAD with ≥ 6 months of clinical follow-up after initial presentation for TBAD or after ascending aorta intervention for patients with repaired type A dissection with residual type B aortic dissection (rTAAD). Patients with prior descending aorta intervention were excluded. The FL and TL of each patient were manually segmented from 4D flow MRI data, and 3D parametric maps of aortic hemodynamics were generated. Groups were divided based on (1) presence vs. absence of AARO and (2) growth rate ≥ vs. < 3 mm/year. True and false lumen kinetic energy (KE), stasis, peak velocity (PV), reverse/forward flow (RF/FF), FL to TL KE ratio, as well as index aortic diameter were compared between groups using the Mann-Whitney U or independent t-test. Results: A total of n = 51 patients (age: 58.4 ± 15.0 years, M/F: 31/20) were included for analysis of AARO. This group contained n = 26 patients with TBAD and n = 25 patients with rTAAD. In the overall cohort, AARO patients had larger baseline diameters, lower FL-RF, FL stasis, TL-KE, TL-FF and TL-PV. Among patients with de novo TBAD, those with AAROs had larger baseline diameter, lower FL stasis and TL-PV. In both the overall cohort and in the subgroup of de novo TBAD, subjects with aortic growth ≥ 3mm/year, patients had a higher KE ratio. Conclusion: Our study suggests that 4D flow MRI is a promising tool for TBAD evaluation that can provide information beyond traditional MRA or CTA. 4D flow has the potential to become an integral aspect of TBAD work-up, as hemodynamic assessment may allow earlier identification of at-risk patients who could benefit from earlier intervention.

The extended PETTICOAT technique does not guarantee favorable remodeling after acute type B aortic dissection.

Introduction: Favorable remodeling is not always observed after thoracic endovascular aortic repair (TEVAR) in acute complicated type B aortic dissection (TBAD). Existing distal re-entries might be the cause of that. Many more extensive techniques have been introduced and evaluated. None of them achieve proven benefit in long-term follow-up. Aim: A new technique called extended PETTICOAT (provisional extension to induce complete attachment) or e-PETTICOAT technique was published in 2018. It allows one to cover proximal and distal re-entries and consists of: combined implantation of a thoracic stent graft to seal the proximal entry; self-expandable stents in the visceral aorta to expand the true lumen; plus two parallel kissing iliac stent grafts below the renal arteries. Despite encouraging medium term results, it has unknown long-term consequences. Material and methods: The prospective observational single center study included 11 patients with complicated acute TBAD qualified for endovascular treatment using the e-PETTICOAT technique. Complicated acute TBAD was identified only in cases of clinical manifestation before or at the time of intervention; radiological findings were not sufficient to identify complications in our study. Method: The 5-year follow-up, based on clinical outcome including survival, re-interventions and angio-CT-assessed remodeling, was examined. Results: The e-PETTICOAT technique achieves good remodeling in 38% of primary and 88% of secondary procedures. Conclusions: The E-PETTICOAT does not guarantee favorable remodeling during a 5-year follow-up in acute complicated TBAD. Complex aortic repair after e-PETTICOAT might be needed.

Surgical and endovascular repair for type B aortic dissections with mesenteric malperfusion syndrome: A systematic review of in-hospital mortality.

Objectives: Mesenteric malperfusion is a feared complication of aortic dissection, with high mortality. The purpose of this study was to systematically review in-hospital mortality (IHM) of endovascular and surgical management of acute and chronic Stanford type B aortic dissections (TBAD) complicated by mesenteric malperfusion (MesMP). Methods: A systematic search of English language articles was conducted in relevant databases. Data on patient demographics, procedure details, and survival outcomes were collected. Reports were classified by type of intervention performed. Studies that failed to report patient-level outcomes based on specific intervention performed or IHM were excluded. Retrospective chart review of previously published data from a single institution was also performed to further identify cases of TBAD that were managed endovascularly. The Fisher exact test was performed to determine statistical significance. Results: In total, 37 articles were suitable for inclusion in this systematic review, which yielded 149 patients with a median age 55.0 years (interquartile range, 46.5-65 years) and 79% being male. Overall, in-hospital mortality was 12.8% (19/149) and was similar between endovascular and open surgical interventions (13% vs 11%, P = .99). Among endovascular strategies, IHM was greater, although not statistically significant in the thoracic endovascular aortic repair group compared with the fenestration/stenting without thoracic endovascular aortic repair group (24% vs 11%, P = .15). Conclusions: Multiple strategies exist for the management of TBAD with MesMP; however, a majority of cases were managed endovascularly. Despite advances in therapies, mortality remains high at 13%.

Thoracic endovascular aortic repair for uncomplicated Type B aortic dissection: What is the optimal time window for intervention?

BACKGROUND: Uncomplicated Type B aortic dissection (un-TBAD) is still managed conservatively with optimal medical therapy (OMT) despite evidence in favour of thoracic endovascular aortic repair (TEVAR) for un-TBAD. OMT aims to regulate heart rate and blood pressure and patients require long-term follow-up to evaluate the extent of dissection, however, many un-TBAD patients are lost to follow-up. Several trials and observational studies evaluated the use of TEVAR in combination with OMT in un-TBAD and proved the safety, effectiveness, and comparability of TEVAR relative to OMT alone. What remains in question is the optimal time window to intervene with TEVAR. This was recently addressed in a fascinating review by Jubouri et al. AIMS: This commentary aims to discuss the recent review by Jubouri et al. which further proved that TEVAR is safe and effective in un-TABD and investigated the optimal timing of TEVAR in un-TBAD. MATERIALS & METHODS: We carried out a literature search using multiple electronic databases including PUBMED and Scopus in order to collate research evidence on intervention timeframe and outcomes of TEVAR in un-TBAD. RESULTS: Performing TEVAR during the subacute phase of dissection (15-90 days since symptom onset) seems to be associated with less periprocedural complications compared to the acute phase, however, late outcomes (>30 days post-TEVAR) are comparable between the two groups and are superior to the chronic phase. DISCUSSION: The introduction of TEVAR in un-TBAD presents a paradigm shift in the management of un-TBAD and a potential move towards becoming the gold-standard treatment option for un-TBAD. Intervening with TEVAR within the first 90 days since symptom onset (acute and subacute un-TBAD) gives favourable outcomes relative to intervention in the chronic phase of dissection (>90 days since symptom onset), this is due to the dissecting septum becoming less compliant over time. CONCLUSION: TEVAR is a safe and effective treatment modality for un-TBAD with a survival benefit compared to OMT alone. Offering TEVAR during the subacute phase of dissection yields optimal results which are comparable to the acute phase but superior to the chronic phase.

Quantitative analysis of renal blood flow during thoracic endovascular aortic repair in type B aortic dissection using syngo iFlow.

BACKGROUND: Currently, the thoracic endovascular aortic repair is the recommended clinical treatment for type B aortic dissections. Unfortunately, malperfusion or ischemia of the kidneys is a major complication of type B aortic dissections. Despite this, few studies have focused on the effects of thoracic endovascular aortic repair on blood flow in renal arteries and parenchyma. This current investigation used novel real-time imaging software to quantitatively analyze the hemodynamic changes in renal artery blood flow and perfusion before and after stent graft placement. METHODS: A total of 51 patients with type B aortic dissection undergoing thoracic endovascular aortic repair between April 2017 and September 2019 were retrospectively recruited. The pre-and post-procedural digital subtraction angiography images were converted into color-coded maps using syngo iFlow for quantitative comparison. Time-intensity curves and related parameters, including the average peak ratio (avg.Pr), average delayed time to peak (avg.dTTP), and average area under the curve ratio (avg.AUCr) of the renal arteries and renal cortex were obtained and analyzed. Wilcoxon signed-rank test was used to compare iFlow parameters before and after endovascular repair. Spearman correlation analyses were performed to study iFlow parameters and renal function parameters and the estimated glomerular filtration rate (eGFR) and blood urea nitrogen (BUN). RESULTS: A total of 102 images including 51 pre-operative and 51 post-operative image datasets were successfully post-processed. Following endovascular repair, syngo iFlow showed a significant 33.0% increase in avg.Pr (P<0.001) and a significant 35.1% increase in avg.AUCr (P<0.001) in the renal artery. Additionally, there was a significant 12.2% decrease in the avg.dTTP (P=0.001), a significant 24.5% increase in avg.Pr (P=0.004), and a significant 38.3% increase in avg.AUCr (P=0.009) in the renal cortex. Spearman correlation analysis showed that after endovascular repair there was a significant correlation between the avg.Pr of the renal artery and eGFR (r=0.30; P=0.0349), the avg.Pr of the renal cortex and eGFR (r=0.30; P=0.0300), and the avg. AUCr of the renal cortex and BUN (r=0.31; P=0.0289). CONCLUSIONS: syngo iFlow provided a novel quantitative method for evaluating renal hemodynamic changes in patients with type B aortic dissection undergoing endovascular treatment. Time-intensity curve parameters may facilitate the intraprocedural evaluation of renal blood flow and perfusion to complement the color-coded map.

Is TEVAR really needed for uncomplicated type B aortic dissection?

Thoracic endovascular aortic repair (TEVAR) has quickly become the mainstay of treatment for acute aortic dissection, in particular cases of acute complicated Stanford Type B dissection (co-TBAD). Necessarily, TEVAR carries with it the risk of postoperative complications, including stroke and renal failure. As a result, the management of patients with uncomplicated type B aortic dissection (un-TBAD), which is generally accepted as being less severe, is safely managed via optimal medical therapy (OMT) alone. However, despite OMT, patients with un-TBAD are at substantial risk of severe disease progression requiring delayed intervention. The cost-benefit ratio associated with TEVAR for un-TBAD is therefore of key interest. Howard and colleagues produced a fascinating systematic review and meta-analysis investigating the clinical outcomes of TEVAR for complicated and uncomplicated TBAD. Their data suggest that there is no significant difference in in-hospital mortality or 5-year survival between TEVAR for un-TBAD and co-TBAD, although the 30-day mortality rate appeared to be higher in the co-TBAD cohort. Patients with co-TBAD appeared to also be at a higher risk of postoperative stroke and TEVAR endoleak, while un-TBAD patients were at a higher risk of postoperative renal failure. Further prospective research into these relationships is recommended to fully elucidate the comparative efficacies of TEVAR for un-TBAD and co-TBAD.

Effect of proximal fixation length on complications after endovascular repair of type B aortic dissection.

OBJECTIVE: We evaluated the effect of the achieved proximal seal length on the outcomes after endovascular repair of acute type B aortic dissection (aTBAD). METHODS: A post hoc analysis was performed using data from two prospective, multicenter investigational studies of the Zenith Dissection Endovascular System (STABLE I and II). Patients treated for aTBAD within 14 days of symptom onset were included if complete preoperative and postoperative imaging data were available for review. The patients were divided into four groups according to the length of the achieved proximal seal according to the centerline imaging findings: ≥20 mm, ≥10 to <20 mm, ≥0 to <10 mm, and <0 mm. The outcomes stratified by the achieved proximal seal length were evaluated. All imaging findings were based on core laboratory analysis. RESULTS: A total of 110 patients were included in the present analysis; 51 were from STABLE I and 59 from STABLE II. Although the study protocol criteria required a ≥20 mm length of nondissected aorta distal to the left common carotid artery to serve as a proximal seal zone, an achieved proximal seal length of ≥20 mm was observed in only 19 of the 110 patients (17.3%) according to the location of stent-graft placement. After a mean follow-up duration of 41.6 ± 21 months, the cumulative rate of the composite device outcome (ie, proximal entry flow, retrograde dissection, transaortic growth, and stent-graft migration) was lowest in patients with an achieved proximal seal length of ≥20 mm (15.8%; 3 of 19). The cumulative rate increased as the seal length decreased (32.0% [8 of 25], 55.6% [20 of 36], and 60.0% [18 of 30] with a proximal seal length of ≥10 to <20 mm, ≥0 to <10 mm, and <0 mm, respectively; P < .01, Cochran-Armitage trend test). CONCLUSIONS: A clear inverse relationship was found between the proximal seal length achieved and associated adverse outcomes. This finding underscores the importance of landing the stent-graft in healthy, nondissected aorta to minimize the risk of complications and provide a durable repair in patients with aTBAD.

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.

Heterologous Production of 1-Tuberculosinyladenosine in Mycobacterium kansasii Models Pathoevolution towards the Transcellular Lifestyle of Mycobacterium tuberculosis.

Mycobacterium kansasii is an environmental nontuberculous mycobacterium that causes opportunistic tuberculosis-like disease. It is one of the most closely related species to the Mycobacterium tuberculosis complex. Using M. kansasii as a proxy for the M. kansasii-M. tuberculosis common ancestor, we asked whether introducing the M. tuberculosis-specific gene pair Rv3377c-Rv3378c into M. kansasii affects the course of experimental infection. Expression of these genes resulted in the production of an adenosine-linked lipid species, known as 1-tuberculosinyladenosine (1-TbAd), but did not alter growth in vitro under standard conditions. Production of 1-TbAd enhanced growth of M. kansasii under acidic conditions through a bacterial cell-intrinsic mechanism independent of controlling pH in the bulk extracellular and intracellular spaces. Production of 1-TbAd led to greater burden of M. kansasii in the lungs of C57BL/6 mice during the first 24 h after infection, and ex vivo infections of alveolar macrophages recapitulated this phenotype within the same time frame. However, in long-term infections, production of 1-TbAd resulted in impaired bacterial survival in both C57BL/6 mice and Ccr2-/- mice. We have demonstrated that M. kansasii is a valid surrogate of M. tuberculosis to study virulence factors acquired by the latter organism, yet shown the challenge inherent to studying the complex evolution of mycobacterial pathogenicity with isolated gene complementation.IMPORTANCE This work sheds light on the role of the lipid 1-tuberculosinyladenosine in the evolution of an environmental ancestor to M. tuberculosis On a larger scale, it reinforces the importance of horizontal gene transfer in bacterial evolution and examines novel models and methods to provide a better understanding of the subtle effects of individual M. tuberculosis-specific virulence factors in infection settings that are relevant to the pathogen.