Entry Tear Research Articles

Intravascular ultrasound assisted sizing in thoracic endovascular aortic repair improves aortic remodeling in Type B aortic dissection.

The precise sizing of the stent graft in thoracic endovascular aortic repair (TEVAR) affects aortic remodeling and hence, further outcome. Covering the proximal entry tear is essential for successful treatment of Type B aortic dissection. Intravascular ultrasound (IVUS) enables real-time aortic diameter assessment, and is especially useful when computed tomography (CT) image quality is poor. IVUS, however, is not routinely utilized due to cost inefficiency. We investigated the impact of IVUS-assisted stent graft sizing on aortic remodeling in TEVAR. In this single-center retrospective study we evaluated patients with Type B aortic dissection undergoing both CT and IVUS before TEVAR. We assessed the aortic diameter at the level of the left subclavian artery via both methods before stent implantation and analyzed due to which method the implanted stent graft was chosen, retrospectively. To determine the degrees of aortic remodeling involved, we evaluated true lumen and false lumen diameters, and total aortic remodeling in CT. We analyzed 45 patients with Type B aortic dissection undergoing TEVAR. The mean ages were 66.9±10.0 years fo0072 IVUS (n = 20) and 62.3±14.2 years for CT-assisted TEVAR (n = 25; p = 0.226). The follow-up time for both groups did not differ between the two groups (IVUS: 22.9±23.1 months, CT: 25.6±23.0 months; p = 0.700). While both methods were associated with advantages regarding aortic remodeling, IVUS-assisted sizing yielded a greater increase in true lumen (30.4±6.2 vs. 25.6±5.3; p = 0.008) and reductions in false lumen (14.4±8.5 vs. 23.9±9.3; p = 0.001) and total aortic diameter (35.5±6.0 vs. 39.9±8.1; p = 0.045). IVUS-guided stent graft sizing in Type B aortic dissection shows beneficial effects on aortic remodeling and might be of additional advantage in aortic diseases, especially when CT image quality is poor.

Total aortic repair for acute type A aortic dissection: a new paradigm.

The currently accepted guidelines of open surgical repair for acute type A aortic dissection (ATAAD) include the resection of the primary entry tear, replacement of the ascending aorta and "hemi-arch" with an open distal anastomosis, and aortic valve resuspension and some form of obliteration of the aortic root false lumen. The principal aim being protection against aortic rupture, aortic regurgitation, and coronary ischemia and restoration of antegrade preferential true lumen perfusion. Proponents argue that this operation is tailored to be in the armamentarium of most cardiac surgeons and deliver the lowest early operative risk, while leaving the infrequent long-term sequelae to be dealt with electively by experienced aortic centres. While a superficially compelling argument, the actual outcomes suggest that it falls significantly short of achieving its noble goals on both acute and chronic counts. This led us to develop a seemingly more radical but in practise safe paradigm, which aims to achieve total aortic healing in the acute phase.

Intimal re-layering technique for type A acute aortic dissection-reconstructing the intimal layer continuity to induce remodeling of the false channel.

Residual false channel is common after repair of type A acute aortic dissection (TAAAD). Starting from our recent series of TAAAD patients we carried out a retrospective analysis, regarding the failure of primary exclusion at the time of the initial operation. We classified the location of the principal entry tears perfusing the residual false channel. The proposed technique represents our attempt to correct the mechanism of false channel perfusion during primary repair. We describe a new technique designed to address some limitations of standard hemiarch aortic replacement. Its goal are: (I) to reinforce the intimal layer at the arch level; (II) to eliminate inter-luminal communications at the arch level using suture lines around the arch vessels; (III) to provide an elephant trunk configuration for further interventions. Between August 2016 and January 2018, 11 patients underwent emergency surgery using this technique; 7 were men; the median age was 74 years. All patients were treated using systemic circulatory arrest under moderate hypothermia (26 °C) and selective cerebral perfusion. All patients had supra-coronary repair; 1 patient had aortic valve replacement + CABG. In the first two patients a manual suture around supra-aortic trunks was used; the subsequent seven patients were treated with a mechanical suture bladeless device. CT scan follow up was performed in all survivors with controls before discharge 3 months and 1 year after operation. No patient died in the operating room and no neurologic deficit was observed in this initial experience. One patient died in POD 5th for low cardiac output syndrome. Median ICU stay was 3 days (IQR, 2-6 days). Hospital mean length of stay was 15.2±8 days. Median cardiopulmonary bypass time was 130 min (IQR, 110-141 min); median arrest time for re-layering was 17 min (IQR, 16-20 min); median total arrest was 36 min (IQR, 29-39 min). Distal aortic anastomosis was performed in zone 0 in 4 patients, zone 1, with innominate replacement, in 5 patients, in zone 2, with branches to innominate and left common carotid arteries, in 2 patients. Median follow up (closing date 06/01/2018) was 443 days (IQR, 262-557 days); no late deaths occurred. No dehiscence at the level of stapler or manual sutures was observed. Proximal 1/3 of the thoracic aorta false channel was obliterated in all cases but one; in 3 cases complete exclusion of the false channel was obtained after operation. In one case stent graft completion was required. This technique combines the advantages of arch replacement to the simplicity of anterior hemiarch repair. This study demonstrates the safety of the procedure and the possibility to induce aortic remodeling without complex arch replacement.

The incidence of delayed complications in acute type B aortic dissections is underestimated

ObjectiveAcute type B aortic dissections (TBADs) can have immediate or delayed complications within the first 2 weeks. Because the majority of clinical series retrospectively categorized TBAD, the incidence and outcome of delayed complications in initially uncomplicated TBAD within the first 14 days are not well described. MethodsWe retrospectively analyzed 86 patients (78% male; age, 62.5 ± 13 years) with acute TBAD treated consecutively between January 2004 and May 2016 at a tertiary referral center. All TBADs were confirmed by computed tomography angiography (CTA) on admission, after 2 to 5 days, and after 10 to 14 days. Study end points were the incidence of immediate and delayed complications (aortic rupture, malperfusion, rapid aortic expansion >4 mm, pain or hypertension resistant to medical therapy) and in-hospital mortality. In addition, we looked at CTA-detected morphometric variables (maximum diameters of descending aorta, false lumen [FL], and primary entry tear; number of intimal tears; FL configuration; true lumen collapse; course of the dissection) and their association with delayed complications. Finally, we assessed treatment modalities and clinical outcomes. ResultsOf all TBADs, 22 (26%) presented with immediate complications (rupture, n = 11); 64 patients (74%) were initially assessed as having uncomplicated TBAD. Of these 64 patients, 24 (28% of all 86) suffered from delayed complications (malperfusion, n = 10; aortic rupture, n = 3; early expansion >4 mm, n = 8; refractory pain, n = 2; uncontrollable hypertension, n = 1) at a median interval of 7.1 (2-14) days after symptom onset. During the first 14 days, 40 patients (46%) remained uncomplicated. The CTA analysis revealed a significant association of initial thoracic aortic diameter (P = .009), size of the primary entry tear (P = .018), true lumen collapse (P = .019), and partially thrombosed FL (P = .019) with the occurrence of delayed complications within the first 14 days. Of the patients with delayed complications, 87.5% underwent surgery (90% thoracic endovascular aortic repair, 10% peripheral revascularization); 12.5% in this group died following aortic rupture before they received surgical repair. The mortality of patients with delayed complicated TBAD was significantly higher compared with those who remained uncomplicated within the 14-day period (12.5% vs 0%; P = .0221). ConclusionsDelayed complications in initially uncomplicated acute TBAD are not infrequent. Morphologic variables like maximum diameter of the descending aorta, primary entry tear, true lumen collapse, and partially thrombosed FL were associated with an increased risk of delayed complications in initially uncomplicated TBAD. Future clinical research must verify the predictive role of clinical and morphologic variables in the acute phase, particularly with regard to a possible early surgical treatment to prevent a fatal outcome.

Long-term outcomes of total arch replacement with the non-frozen elephant trunk technique for Stanford Type A acute aortic dissection.

Arch repair using the frozen elephant trunk (FET) technique has been utilized to treat Type A acute aortic dissection. In contrast, the long-term outcomes of the non-FET technique focus on the thrombosed false lumen (FL), and distal aortic reoperation rates remain unclear. The goal of our study was to investigate the efficacy and long-term outcomes of the non-FET technique as the benchmark. We reviewed 518 patients with Type A acute aortic dissection in the last 20 years. Among them, 139 hospital survivors (61 ± 12 years) who had undergone total arch replacement with the non-FET technique were enrolled. A total of 86% (120/139) of patients had a patent FL at the descending aorta preoperatively. The median follow-up period was 41 (1-219) months. No spinal cord ischaemia and new entry tear formation were observed. Postoperative FL thrombosis of the entire descending aorta was obtained in 47% (66/139) and in 39% (47/120) of patients who had a patent FL preoperatively. Freedom from dissection-related distal reoperation rates at 1, 3, 5 and 10 years were 87%, 83%, 81% and 78%, respectively. The results of multivariate analysis indicated that the predictors of a dissection-related reoperation were connective tissue disease [hazard ratio (HR) 4.6, P = 0.006], re-entry at the superior mesenteric artery (HR 2.9, P = 0.04), unachieved primary entry resection (HR 5.3, P = 0.001) and preoperative maximum descending aortic diameter ≥38 mm (HR 11.6, P < 0.001). Total arch replacement with the non-FET technique was safe and reliable from the viewpoint of spinal cord ischaemia. Further comparative studies between the FET and the non-FET techniques are required.

Coupled Morphological-Hemodynamic Computational Analysis of Type B Aortic Dissection: A Longitudinal Study.

Progressive false lumen aneurysmal degeneration in type B aortic dissection (TBAD) is a complex process with a multi-factorial etiology. Patient-specific computational fluid dynamics (CFD) simulations provide spatial and temporal hemodynamic quantities that facilitate understanding this disease progression. A longitudinal study was performed for a TBAD patient, who was diagnosed with the uncomplicated TBAD in 2006 and treated with optimal medical therapy but received surgery in 2010 due to late complication. Geometries of the aorta in 2006 and 2010 were reconstructed. With registration algorithms, we accurately quantified the evolution of the false lumen, while with CFD simulations we computed several hemodynamic indexes, including the wall shear stress (WSS), and the relative residence time (RRT). The numerical fluid model included large eddy simulation (LES) modeling for efficiently capturing the flow disturbances induced by the entry tears. In the absence of complete patient-specific data, the boundary conditions were based on a specific calibration method. Correlations between hemodynamics and the evolution field in time obtained by registration of the false lumen are discussed. Further testing of this methodology on a large cohort of patients may enable the use of CFD to predict whether patients, with originally uncomplicated TBAD, develop late complications.

What is the optimal surgical strategy for Stanford Type A acute aortic dissection in patients with a patent false lumen at the descending aorta?

Aggressive total arch replacement (TAR) to obtain thrombosis of the distal false lumen (FL) in patients with Stanford Type A acute aortic dissection, particularly with a patent FL at the descending aorta, is discussed. The aim of this study was to examine the efficacy of our strategy. In the last 20 years, we retrospectively reviewed the records of 518 patients with Type A acute aortic dissection who underwent an emergent surgery. Among them, 290 patients with a preoperative patent FL at the descending aorta were enrolled in this study. Patients were divided in 2 groups: the non-TAR group (n = 124; 68 ± 14 years) and the TAR group (n = 166; 61 ± 13 years). In-hospital mortality was 11% (32/290) without significant difference between the 2 groups (the non-TAR group 13% vs the TAR group 10%, P = 0.45). The rates of FL thrombosis of the entire descending aorta were detected at 32% in the non-TAR group and 41% in the TAR group (P = 0.16). Freedom from distal aortic dilatation ≥50 mm was significantly higher in the TAR group (P = 0.03) than in the non-TAR group. Independent predictors of distal aortic dilatation >50 mm were patients in the non-TAR group (P = 0.01; hazard ratio 3.1, 95% confidence interval 1.28-8.05) and unachieved primary entry tear resection (P = 0.002; hazard ratio 6.2, 95% confidence interval 1.38-8.66). Our surgical strategy with an aggressive entry resection with higher rate of TAR was acceptable. In patients with a patent FL at the descending aorta, TAR should be considered to prevent the future growth of the distal aorta.

Endovascular creation and validation of acute in vivo animal model for type A aortic dissection

BackgroundAnimal modeling is a prerequisite for clinical transfer of new therapies. This study targets an acute in vivo animal model of type A dissection using endovascular approach with a view to test future stent grafts dedicated to this aortic segment. MethodsExperiments were conducted on 13 swine. Two arterial accesses, femoral and percutaneous transapical, were required. Entry tear was created by endovascular instrumental means inserted through transapical access with either Outback catheter (group 1, n = 3) or EchoTip Endoscopic Ultrasound Needle (group 2, n = 10). Afterward, dissection extension was obtained in antegrade direction by looped guidewire technique, and, as often as possible, re-entry tear was created with either looped guidewire or Outback catheter. Finally, entry tear, dissected space, and re-entry tear when existing were dilated with 8-mm balloon. In our acute model, animals were euthanized at the end of the experiment day, and aortas were explanted for macroscopic and histologic examination. ResultsThe model was successfully created in 10 out of 13 animals. In group 1, dissection was limited to arch with 23 mm average length and no possibility of achieving re-entry tear. One aortic perforation was observed. In group 2, dissection was extended up to descending thoracic or thoracoabdominal aorta, with 110 mm average length (range 40-165 mm), and re-entry tear was created in seven cases. Histologic examination confirmed the presence of intimo-medial flap. ConclusionsThe present experiment validates a new type A dissection animal model, which morphologically reproduces human aortic dissection features. As such, it provides an advantageous basis for testing future stent grafts.

The potential role of quantitative digital subtraction angiography in evaluating type B chronic aortic dissection during TEVAR: preliminary results.

To evaluate the role of quantitative digital subtraction angiography (Q-DSA) with parametric color coding (PCC) in assessing patients with type B chronic thoracic aortic dissection (TBCAD) during thoracic endovascular aortic repair (TEVAR) procedures. A total of 11 patients electively treated in our Department for a TBCAD were retrospectively enrolled. All cases were treated with TEVAR for false lumen aneurysm of the thoracic descending aorta. For digital subtraction angiography (DSA) series post-processing, a newly implemented PCC algorithm was used to turn consecutive two-dimensional images into a single color-coded picture (syngo iFLOW, Siemens AG, Forchheim, Germany). In consensus reading, two clinicians experienced in vascular imaging evaluated the DSA series in blinded assessment and compared them to the color-coded images. PCC was assessed for its accuracy in identifying the true and false lumen as well as whether it could provide improved visualization in pre-deployment stent grafting and the final evaluation of treatment. PCC facilitated the visualization of the aortic dissection angioarchitecture in terms of contemporary true and false lumen vision in 81.8% of the cases. In 72.7% of the procedures, Q-DSA was estimated to improve aorta information assessment in terms of false lumen viewing, and it was possible to identify the proximal entry tear position in 45.4% of the cases. After stent graft deployment, in 72.7% of the cases (all 8 patients in which the aortic arch false lumen was visible in pre-treatment), Q-DSA confirmed the absence of early false lumen reperfusion. Our results indicate that Q-DSA could be useful in the intraprocedural evaluation of patients with aortic dissection during TEVAR procedures without additional x-ray costs and contrast exposure.

Zone zero thoracic endovascular aortic repair: A proposed modification to the classification of landing zones

ObjectiveEndovascular stent-grafting provides an alternative treatment option for high-risk patients with ascending aortic disease. The feasibility of this approach has been demonstrated before. We assess the updated experience with ascending thoracic endovascular aortic repair and propose a modification of the landing zone classification based on the outcomes. MethodsFrom 2006 to 2016, 39 patients deemed very high risk for open replacement underwent endovascular repair of ascending aorta for acute type A dissection (12, 31%), intramural hematoma (2, 5%), pseudoaneurysm (22, 56%), and chronic dissection suture line entry tear (3, 8%). Ascending thoracic endovascular aortic repair was performed in 36 patients. In 3 patients with pseudoaneurysm, occluder devices were used. Computed tomography imaging analysis was performed, and the extent of aortic pathology was designated by segmental proximity to the left ventricle. Segmental anatomy of the proximal aorta was designed as zone 0A from the annulus to the distal margin of highest coronary, 0B extends from above the coronary to the distal margin of right pulmonary artery, and 0C extends from the right pulmonary artery border to the innominate artery. Multivariable time to event Cox regression analysis was performed to predict mortality, and long-term survival was estimated using the Kaplan–Meier method. ResultsOperative mortality was 13%; all 5 deaths occurred after emergency ascending thoracic endovascular aortic repair for type A dissection. Other complications included stroke in 4 patients (10%), myocardial infarction in 2 patients (5%), tracheostomy in 2 patients (5%), and dialysis in 2 patients (5%). In patients with acute type A dissection, the ascending pathology extended into zone 0A in 10 (71%) and 0B in 4 (29%). Among those with pseudoaneurysm, the location of the defect was in 0B in 11 (50%), 0C in 10 (45%), and 0A in 1. Among the patients with chronic dissection, the defect was located in 0C in all 3 (100%). After multivariable adjustment, Cox regression predicted significantly higher hazard of mortality with disease involving zone 0A versus 0C (P = .020) and older age (P = .026). Kaplan–Meier estimate of survival was also significantly worse in patients with disease extension into 0A versus 0C (P = .0018). At 30 days, 1 year, and 5 years, the overall survival was 81%, 74%, and 64% and freedom from reintervention was 85%, 77%, and 68%, respectively. ConclusionsThe modified zone zero classification is useful for characterizing extent of ascending aortic pathology and assessing prognosis. Location of the defect varies by pathology, and the presence of 0A disease predicts worse outcomes. Design of endovascular devices should be tailored to the aortic pathology and zone characteristics.

A computational model for false lumen thrombosis in type B aortic dissection following thoracic endovascular repair

Thoracic endovascular repair (TEVAR) has recently been established as the preferred treatment option for complicated type B dissection. This procedure involves covering the primary entry tear to stimulate aortic remodelling and promote false lumen thrombosis thereby restoring true lumen flow. However, complications associated with incomplete false lumen thrombosis, such as aortic dilatation and stent graft induced new entry tears, can arise after TEVAR. This study presents the application and validation of a recently developed mathematical model for patient-specific prediction of thrombus formation and growth under physiologically realistic flow conditions. The model predicts thrombosis through the evaluation of shear rates, fluid residence time and platelet distribution, based on convection-diffusion-reaction transport equations. The model was applied to 3 type B aortic dissection patients: two TEVAR cases showing complete and incomplete false lumen thrombosis respectively, and one medically treated dissection with no signs of thrombosis. Predicted thrombus growth over time was validated against follow-up CT scans, showing good agreement with in vivo data in all cases with a maximum difference between predicted and measured false lumen reduction below 8%. Our results demonstrate that TEVAR-induced thrombus formation in type B aortic dissection can be predicted based on patient-specific anatomy and physiologically realistic boundary conditions. Our model can be used to identify anatomical or stent graft related factors that are associated with incomplete false lumen thrombosis following TEVAR, which may help clinicians develop personalised treatment plans for dissection patients in the future.

Role of Re-entry Tears on the Dynamics of Type B Dissection Flap

Mortality during follow-up after acute Type B aortic dissection is substantial with aortic expansion observed in over 59% of the patients. Lumen pressure differential is considered a prime contributing factor for aortic dilation after propagation. The objective of the study was to evaluate the relationship between changes in vessel geometry with and without lumen pressure differential post propagation in an ex vivo porcine model with comparison with patient clinical data. A pulse duplicator system was utilized to propagate the dissection within descending thoracic porcine aortic vessels for set proximal (%circumference of the entry tear: 40%, axial length: 2 cm) and re-entry (50% of distal vessel circumference) tear geometry. Measurements of lumen pressure differential were made along with quantification of vessel geometry (n = 16). The magnitude of mean lumen pressure difference measured after propagation was low (~ 5 mmHg) with higher pressures measured in false lumen and as anticipated the pressure difference approached zero after the creation of distal re-entry tear. False lumen Dissection Ratio (FDR) defined as arc length of dissected wall divided by arc length of dissection flap, had mean value of 1.59 ± 0.01 at pressure of 120/80 mmHg post propagation with increasing values with increase in pulse pressure that was not rescued with the creation of distal re-entry tear (p < 0.01). An average FDR of 1.87 ± 0.27 was measured in patients with acute Type B dissection. Higher FDR value (FDR = 1 implies zero dissection) in the presence of distal re-entry tear demonstrates an acute change in vessel morphology in response to the dissection independent of local pressure changes challenges the re-apposition of the aortic wall.

Legitimacy of Entry-Oriented Strategy in DeBakey I Dissection in the Era of Endovascular Therapy.

Legitimacy of entry-oriented therapy for DeBakey I aortic dissection is of eminent importance in the era of emerging ascending aorta endovascular therapy. This study aims to evaluate early, midterm, and reintervention results of entry-oriented operative strategy compared to more aggressive strategies for treatment of DeBakey type I aortic dissection with an isolated intimal tear in the ascending aorta. This study prospectively followed 98 consecutive patients who received an operation for DeBakey type I aortic dissection with the intimal tear in the ascending aorta between 2007 and 2013 for up to 6 years. Follow-up included survival, medical therapy, CT-imaging results, and reinterventions. Patients were grouped into entry-oriented (group I) receiving an isolated replacement of the ascending aorta and/or hemiarch (65 patients); and aggressive therapy (group II) receiving a replacement of the ascending aorta and complete aortic arch (33 patients).Results: The in-hospital mortality was 19% and 23% respectively. The 3-year survival was 52% and 47% respectively (P = .193). Group II showed no advantage regarding persistence or progression of the dissection, thrombosis of false lumen, increase in aortic diameter, peripheral organ malperfusion (as assessed by follow-up computed tomography imaging) or freedom from reintervention.Conclusion: In treating DeBakey I aortic dissection with an entry tear in the ascending aorta, it might be legitimate to adopt an entry-oriented operative strategy. Further research is also needed to clearly describe the indication of extending the operative strategy in such cases.

Case Report of Extensive Isolated Spontaneous Celiac Trunk Dissection After Liver Transplantation

Arterial dissection is a rare complication after liver transplantation (LT). We report a case of extensive isolated spontaneous celiac trunk dissection (ISCTD) up to the proper hepatic artery, left gastric artery, and splenic artery after living donor liver transplantation. A 48-year-old woman with cryptogenic liver cirrhosis underwent living donor liver transplantation. Intraoperative and postoperative Doppler ultrasound revealed sufficient flow in the hepatic artery, portal vein, and hepatic vein. On postoperative day (POD) 10, Doppler ultrasound showed reduction of hepatic arterial flow. On POD 16, a contrast-enhanced computed tomography scan showed that the ISCTD extended to the proper hepatic artery, left gastric artery, and splenic artery with an entry tear on the proximal side of the celiac trunk. Although the computed tomography scan showed ischemia of a small part of the liver, blood flow to the liver was kept to some extent. Because all false lumens were occluded by thrombi and the liver enzyme levels normalized, we chose conservative therapy with antiplatelet agents. The patient was discharged on POD 53. She remains well without any liver dysfunction after 18 months with reduction in all false lumens and a patent hepatic artery. Several cases of ISCTD have been reported apart from LT, most of which were treated with conservative therapy. We conclude that conservative therapy could be the first choice in ISCTD even after LT.

Predictors of late aortic intervention in patients with medically treated type B aortic dissection

BackgroundPatients with medically managed type B aortic dissection (TBAD) have a high incidence of aorta-related complications over time. Whereas early thoracic endovascular aortic repair (TEVAR) to seal the entry tear can promote aortic remodeling and prevent late aneurysm formation, there are sparse data as to which patients will benefit from such therapy. The goal of this study was to identify clinical and anatomic factors that are associated with the need for subsequent aortic intervention in patients who present with uncomplicated TBAD. These factors could guide the selection of patients who will benefit from TEVAR in the subacute phase. MethodsPatients who presented with acute uncomplicated TBAD and were initially managed medically from January 2000 to December 2013 were included in the study. Timing of intervention was stratified into early (within 180 days of initial presentation) and late (181 days and later) cohorts. All patients had follow-up axial imaging studies. These imaging studies were reviewed for anatomic criteria in a retrospective fashion. Predictors of aortic intervention were determined using Cox regression analyses. ResultsThere were 254 patients (65% men) with medically managed acute TBAD. The average age at presentation was 66.3 years, and 82.5% had a history of hypertension. Mean follow-up was 6.8 years (range, 0.1-13.6 years). There were a total of 97 (38%) patients who required an aortic intervention during follow-up; 30 (12%) patients required an early intervention, and 67 (26%) were treated during late follow-up (100% for aneurysmal degeneration). Predictors of late aortic intervention included entry tear >10 mm (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.5-3.8; P = .03), total aortic diameter >40 mm at time of presentation (OR, 2.2; 95% CI, 1.8-4.3; P = .02), false lumen diameter >20 mm (OR, 1.8; 95% CI, 1.3-4.7; P = .03), and increase in total aortic diameter >5 mm between serial imaging studies (OR, 2.3; 95% CI, 1.3-3.5; P = .02). Complete thrombosis of the false lumen was protective against late operative intervention (OR, 0.22; 95% CI, 0.11-0.48; P < .01). ConclusionsNearly 40% of patients who present with an uncomplicated TBAD will ultimately require an aortic intervention. All of the late interventions were performed for aneurysmal degeneration. A variety of readily available anatomic features can predict the need for eventual operative intervention in TBAD; accordingly, these parameters can guide the desirability of early TEVAR.

Novel Morphological Features for Prediction of Distal Thoracic Aortic Enlargement after Thoracic Endovascular Aortic Repair of DeBakey IIIb Aortic Dissection

Identifying the risk factors predisposing to aortic enlargement after thoracic endovascular aortic repair (TEVAR) is needed for DeBakey IIIb aortic dissection. The aim of the study is to assess the novel morphological features for DeBakey IIIb aortic dissection in predicting distal thoracic aortic enlargement after TEVAR. Sixty-seven patients who underwent TEVAR for DeBakey IIIb aortic dissection between January 2011 and December 2013 at our center were divided based on preoperative computer tomography angiography (CTA) features into 3 groups: I (n=27) and III (n=9), with true and false lumen, respectively, coursing closely along thoracic vertebral bodies and II, spiral configuration (n=31). Distal thoracic aortic enlargement was determined using preoperative and postoperative CTA images. At median 12.2 (interquartile range, 4.3-26.6) months, 12 patients developed distal thoracic aortic enlargement, with estimated cumulative incidence tending to increase from categories I to III (P for trend<0.01). Categories II and III versus I had more frequently concave location of primary entry tear (P<0.01), larger dissection length and height index (L/Hi) (P=0.05), and greater number of abdominal small branches involved preoperatively (P=0.03), with otherwise similar baseline characteristics; and significantly greater total aortic diameter increase and lower false lumen regression up to 24months, and lower true lumen expansion up to 12months. In multivariable regression analysis, categories II and III were independently associated with distal thoracic aortic enlargement (hazard ratio, 19.95 [95% confidence interval, 2.14-186.09]; 41.23 [3.61-470.22], respectively) after adjustment for Society of Vascular Surgery score, preoperative maximum total aortic diameter, L/Hi, and number of abdominal small branches involved preoperatively. The CTA-based morphological features described in this study might improve preoperative risk stratification of DeBakey IIIb aortic dissection, with categories II and III having higher risk of distal thoracic aortic enlargement after TEVAR.

Implantation of Unibody Single-Branched Stent Graft for Patients with Type B Aortic Dissections Involving the Left Subclavian Artery: 1-Year Follow-Up Outcomes.

To report the early results of castor device, a kind of unibody single-branched stent graft, in the treatment of type B aortic dissection (TBAD) involving the LSA. From April 2013 to February 2014, 21 patients with TBADs underwent TEVAR with LSA revascularization by unibody single-branched stent grafts. Three patients with penetrating aortic ulcers in the aortic arch received additional reconstruction of left common carotid artery with chimney technique. Follow-up evaluations were conducted with computed tomography angiography (CTA) at 6, 12months and annually after that. All of the proximal entry tears were completely excluded. Good patency of the grafts was found in all cases. A small type I endoleak occurred in one patient during the procedure. Perioperative mortality is null, and there was no occurrence of serious complications. All patients completed the follow-up except one lost contact after discharge. One death occurred within 6months after the operation, resulting from myocardial infarction, considered unrelated to the stent implantation. No endoleak occurred during follow-up. One compression of a chimney stent and one twist of side branch graft of castor were observed in 2 different patients, respectively. In other cases, CTA scans showed good patency of both the branched and chimney grafts. Two patients had partial thrombosis of the false lumen during follow-up. In other patients, complete thrombosis in the false lumen in thoracic aorta was revealed. The single-branched stent graft was safe and efficient in the 1-year follow-up. Further studies are required to determine its long-term outcomes.

New type A dissection after acute type B aortic dissection

ObjectiveAortic dissection is a dynamic process that can progress both proximal and distal to the initial entry tear. We sought to determine associations for development of proximal progression or new type A aortic dissection (NTAD) after acute type B dissection (ATBD) and its effect on survival of the patient. MethodsWe reviewed all cases of acute aortic dissection that we managed from 1999 to 2014. Univariate and bivariate analyses were performed to identify correlates of NTAD. Multivariable regression and proportional hazards regression analysis was done to determine the effect of dissection progression on long-term survival. ResultsAmong 477 cases of ATBD managed, 19 (4.0%) patients developed NTAD during a median follow-up of 4.1 (interquartile range, 1.4-7.7) years. Median time from diagnosis of ATBD to NTAD was 124 (interquartile range, 23-1201) days. Baseline predictors for development of NTAD at initial ATBD admission included bicuspid aortic valve (P = .006) and age <60 years (P = .012). Although not statistically significant, point estimates indicate that thoracic endovascular aortic repair was twice as frequent in NTAD cases as in non-NTAD cases. Overall 5-year survival was 70.2%. Patients who had repair of NTAD appear to have longer survival, although this effect is on the margin of statistical significance (P = .051). After risk factor and correlates of NTAD adjustment, this effect was no longer apparent (P = .089). ConclusionsThe natural history of ATBD is such that there is a persistent risk of NTAD, with the highest risk in the first 6 months. Factors associated with NTAD include bicuspid aortic valve and young age. Thoracic endovascular aortic repair did not have a large effect on risk. Timely diagnosis and repair of NTAD are associated with good survival rates. Lifelong surveillance is warranted in all cases of descending thoracic aortic dissection regardless of initial treatment modality.

A Feasibility Study of Off-the-Shelf Scalloped Stent-Grafts in Acute Type B Aortic Dissection

Purpose: To evaluate the applicability of an off-the-shelf scalloped stent-graft to preserve left subclavian artery (LSA) flow in thoracic endovascular aortic repair (TEVAR) for acute type B aortic dissection. Methods: The computed tomography angiograms (CTA) of 70 consecutive patients (median age 64 years; 44 men) with acute Stanford type B aortic dissection were retrospectively analyzed to identify patients in whom a short proximal landing zone (<15 mm from the retrogradely dissected wall layers) would require LSA overstenting during TEVAR. A scalloped stent-graft was deemed possible in those patients with the intimal entry tear located at least 20 mm distant from the LSA ostium. Results: The LSA needed to be covered in 56 (80%) patients. Of these, an off-the-shelf scalloped stent-graft would have been applicable in 23 (41%) patients. In the latter group, the median aortic diameter was 31 mm (range 26–37), the median length of the LSA ostium was 13 mm (range 10–20), and the median width of the LSA ostium was 15 mm (range 11–24). Three differently sized off-the-shelf stent-grafts with the largest scallop possible could have adequately treated 20 (36%) of the 56 patients in the acute phase. Conclusion: In this single-center imaging-based study, involvement of the LSA in the setting of acute type B aortic dissection was seen in 80% of patients treated with TEVAR. Three off-the-shelf stent-grafts would suffice to treat one-third of these acute type B aortic dissections and may offer a relatively simple solution to preserve LSA flow, thereby lowering the risk of malperfusion of the (posterior) cerebrum, spinal cord, and left arm in an urgent/emergent setting.

Morphologic characteristics and endovascular treatment of primary infrarenal aortic dissections

ObjectiveWe report the morphologic characteristics and endovascular treatment of primary infrarenal aortic dissections (PIRADs). MethodsA retrospective study was conducted with 38 consecutive PIRAD patients between January 2010 and May 2016 in our vascular center. Patient demographics, morphologic characteristics, endovascular modalities, and periprocedural and follow-up outcomes were recorded. Patients with symptomatic PIRADs or asymptomatic PIRADs of a maximum diameter >30 mm were indicated for endovascular aneurysm repair (EVAR). We proposed a morphologic categorization of PIRADs into two types (I and II) according to the location of the entry tears and an endovascular strategy for treating type I PIRADs with tubular stent grafts (SGs) and type II PIRADs with bifurcated SGs. ResultsAccording to the categorization, the study recruited 13 patients with type I and 25 patients with type II PIRADs. The patients were predominantly men, with an average age of 60.8 ± 15.2 years. Type I PIRADs usually had larger true lumens (22.6 ± 6.3 vs 13.6 ± 4.0 mm; P = .002) and relatively smaller false lumens (8.4 ± 2.3 vs 19.9 ± 16.1 mm; P = .012). Type II PIRADs had more entry tears (2.2 ± 0.6 vs 1.7 ± 0.6; P = .024) and longer dissections (109.4 ± 38.8 vs 73.9 ± 39.0 mm; P = .011). All patients underwent EVAR, with 19 tubular and 22 bifurcated SGs. One patient died during the hospital stay. The technical success rate was 94.8% (36/38), and the clinical success rate was 97.4% (37/38). During follow-up of 36 patients for 28.8 ± 17.7 months, 2 patients with type II PIRADs developed left iliac extension occlusion at 3 and 6 months after EVAR, and only 1 patient underwent reintervention. All patients survived throughout the follow-up. No endoleak or aortic enlargement was observed. Computed tomography angiography demonstrated a patent infrarenal aorta with completely thrombosed false lumen in all PIRAD patients (36/36 [100.0%]). In both types of PIRAD, EVAR yielded a significant decrease in the maximum diameter of the infrarenal aorta, with a significant increase in the true lumen size and a significant decrease in the false lumen size (P < .05). ConclusionsThe morphologic categorization of PIRADs based on the location of the entry tears appeared to be feasible. The endovascular strategy was safe and effective, with high rates of technical success and clinical success and favorable follow-up outcomes.