CRIMSON: An open-source software framework for cardiovascular integrated modelling and simulation.

In this work, we describe the CRIMSON (CardiovasculaR Integrated Modelling and SimulatiON) software environment. CRIMSON provides a powerful, customizable and user-friendly system for performing three-dimensional and reduced-order computational haemodynamics studies via a pipeline which involves: 1) segmenting vascular structures from medical images; 2) constructing analytic arterial and venous geometric models; 3) performing finite element mesh generation; 4) designing, and 5) applying boundary conditions; 6) running incompressible Navier-Stokes simulations of blood flow with fluid-structure interaction capabilities; and 7) post-processing and visualizing the results, including velocity, pressure and wall shear stress fields. A key aim of CRIMSON is to create a software environment that makes powerful computational haemodynamics tools accessible to a wide audience, including clinicians and students, both within our research laboratories and throughout the community. The overall philosophy is to leverage best-in-class open source standards for medical image processing, parallel flow computation, geometric solid modelling, data assimilation, and mesh generation. It is actively used by researchers in Europe, North and South America, Asia, and Australia. It has been applied to numerous clinical problems; we illustrate applications of CRIMSON to real-world problems using examples ranging from pre-operative surgical planning to medical device design optimization.

Cardiac remodelling following thoracic endovascular aortic repair for descending aortic aneurysms.

OBJECTIVES: Current endografts for thoracic endovascular aortic repair (TEVAR) are much stiffer than the aorta and have been shown to induce acute stiffening. In this study, we aimed to estimate the impact of TEVAR on left ventricular (LV) stroke work (SW) and mass using a non-invasive image-based workflow. METHODS: The University of Michigan database was searched for patients treated with TEVAR for descending aortic pathologies (2013-2016). Patients with available pre-TEVAR and post-TEVAR computed tomography angiography and echocardiography data were selected. LV SW was estimated via patient-specific fluid-structure interaction analyses. LV remodelling was quantified through morphological measurements using echocardiography and electrocardiographic-gated computed tomography angiography data. RESULTS: Eight subjects were included in this study, the mean age of the patients was 68 (73, 25) years, and 6 patients were women. All patients were prescribed antihypertensive drugs following TEVAR. The fluid-structure interaction simulations computed a 26% increase in LV SW post-TEVAR [0.94 (0.89, 0.34) J to 1.18 (1.11, 0.65) J, P = 0.012]. Morphological measurements revealed an increase in the LV mass index post-TEVAR of +26% in echocardiography [72 (73, 17) g/m2 to 91 (87, 26) g/m2, P = 0.017] and +15% in computed tomography angiography [52 (46, 29) g/m2 to 60 (57, 22) g/m2, P = 0.043]. The post- to pre-TEVAR LV mass index ratio was positively correlated with the post- to pre-TEVAR ratios of SW and the mean blood pressure (ρ = 0.690, P = 0.058 and ρ = 0.786, P = 0.021, respectively). CONCLUSIONS: TEVAR was associated with increased LV SW and mass during follow-up. Medical device manufacturers should develop more compliant devices to reduce the stiffness mismatch with the aorta. Additionally, intensive antihypertensive management is needed to control blood pressure post-TEVAR.

Correction: Changes in aortic pulse wave velocity of four thoracic aortic stent grafts in an ex vivo porcine model.

[This corrects the article DOI: 10.1371/journal.pone.0186080.].

Changes in aortic pulse wave velocity of four thoracic aortic stent grafts in an ex vivo porcine model.

OBJECTIVES: Thoracic endovascular aortic repair (TEVAR) has been shown to lead to increased aortic stiffness. The aim of this study was to investigate the effect of stent graft type and stent graft length on aortic stiffness in a controlled, experimental setting. METHODS: Twenty porcine thoracic aortas were connected to a pulsatile mock loop system. Intraluminal pressure was recorded at two sites in order to measure pulse wave velocity (PWV) for each aorta: before stent graft deployment (t1); after deployment of a 100-mm long stent graft (t2); and after distal extension through deployment of a second 100-mm long stent graft (t3). Four different types of stent grafts (Conformable Gore® TAG® Device, Bolton Relay® Device, Cook Zenith Alpha™, and Medtronic Valiant®) were evaluated. RESULTS: For the total cohort of 20 aortas, PWV increased by a mean 0.6 m/s or 8.9% of baseline PWV after deployment of a 100-mm proximal stent graft (P<0.001), and by a mean 1.4 m/s or 23.0% of baseline PWV after distal extension of the stent graft (P<0.001). Univariable regression analysis showed a significant correlation between aortic PWV and extent of stent graft coverage, (P<0.001), but no significant effect of baseline aortic length, baseline aortic PWV, or stent graft type on the percentual increase in PWV at t2 or at t3. CONCLUSIONS: In this experimental set-up, aortic stiffness increased significantly after stent graft deployment with each of the four types of stent graft, with the increase in aortic stiffness depending on the extent of stent graft coverage.

Impact of Thoracic Endovascular Repair on Pulsatile Aortic Strain in Acute Type B Aortic Dissection: Preliminary Results.

BACKGROUND: The impact of thoracic endovascular aortic repair (TEVAR) on pulsatile aortic strain remains undetermined in patients with Type B aortic dissection (TBAD). Therefore, we quantified pulsatile aortic strain in TBAD patients and control subjects. METHODS: We retrospectively analyzed two TBAD patients from our database with cardiac-gated computed tomography angiography imaging available before and after TEVAR and two control subjects (67- and 76-year-old males). Patient 1 (54-year-old female) presented with acute TBAD, and Patient 2 (55-year-old male) had Marfan syndrome and ruptured acute TBAD. Custom-developed software was used to compute aortic length, diameter, and area during the cardiac cycle. Pulsatile strain was calculated as systolic increments of length and circumference divided by corresponding diastolic values. RESULTS: Before TEVAR, pulsatile longitudinal strain of the thoracic aorta was lower in TBAD patients (1.4-1.7%) than in control subjects (2.1-4.5%). After TEVAR, pulsatile longitudinal strain increased proximal to the stent-graft by 65% in the arch of Patient 1 and by 70% in the ascending aorta of Patient 2. Pulsatile circumferential strain was elevated in false lumen patency (4.4-6.2%) compared with thrombosed false lumen (1.4-2.1%) or control subjects (0.9-3.3%). Following TEVAR, circumferential measurements within stented segments were deemed unreliable due to artifacts. CONCLUSIONS: TEVAR led to a considerable increase of pulsatile longitudinal strain proximal to the stent-grafts, and TBAD was associated with longitudinally stiffer aortas, which may be part of the pathophysiology of TEVAR-related complications such as retrograde dissection and aneurysmal dilatation. These preliminary data call for larger prospective studies.

Early Outcomes of Acute Retrograde Dissection From the International Registry of Acute Aortic Dissection.

To provide data on the management and outcomes of patients with acute retrograde aortic dissection (AD) originating from a tear in the descending aorta with extension into the aortic arch or ascending aorta. All patients enrolled in the International Registry of Acute Aortic Dissection from 1996-2015 were reviewed. Retrograde AD was defined by primary tear in the descending aorta with proximal extension into the arch or ascending aorta. Primary end points were in-hospital management strategy and mortality. We identified 101 patients with retrograde AD (67 men; 63.2 ± 14.0 years). During index hospitalization, medical (MED), open surgical (SURG), and endovascular (ENDO) therapies were undertaken in 44, 33, and 22 patients, respectively. The SURG group presented with larger ascending aorta (P = 0.04) and more frequent ascending aortic involvement (81.8% [27/33] vs 22.7% [15/66], P < 0.001) compared with the MED and ENDO groups. Early mortality rate was 9.1% (4/44), 18.2% (6/33), and 13.6% (3/22), for the MED, SURG, and ENDO groups (P = 0.51), respectively. A favorable early mortality rate was observed in patients with retrograde extension limited to the arch (8.6% [5/58]) vs into the ascending aorta (18.6% [8/43], P = 0.14). Early mortality rate of patients with retrograde AD with primary tear in the descending aorta (12.9% [13/101]) was significantly lower than those with classic type A AD presenting with primary tear in the ascending aorta (20.0% [195/977], P = 0.001). A subset of patients with acute retrograde AD originating from primary tear in the descending aorta might be managed less invasively with acceptable early results, particularly among those with proximal extension limited to the arch.

Stent-Graft Deployment Increases Aortic Stiffness in an Ex Vivo Porcine Model.

BACKGROUND: Aortic stiffness is an independent predictor of cardiovascular mortality. In this study, the effect of thoracic endovascular aortic repair (TEVAR) on aortic stiffness is investigated by measuring aortic pulse wave velocity (PWV) in an ex vivo porcine model. METHODS: Fifteen fresh porcine thoracic aortas were connected to a benchtop pulsatile system. Intraluminal pressures were recorded in the ascending aorta and at the celiac trunk using a needle connected to a pressure sensor. The distance between the needles was divided by the time difference between the base of the pressure peaks to calculate aortic PWV at baseline and after stent-graft deployment and distal stent-graft extension. RESULTS: Mean aortic PWV was 5.0 m/s at baseline. PWV increased by 4% after proximal stent-graft deployment (P = 0.09) and by 18% after stent-graft extension (P < 0.001). Pulse pressure in the nonstented ascending aorta increased by 11.0 ± 1.2 mm Hg after proximal stent-graft deployment (P < 0.001) and by 17.3 ± 1.5 mm Hg after stent-graft extension (P < 0.001). The increases in PWV and pulse pressure showed a positive linear correlation with the percentage of stent-graft coverage (P < 0.001 and P < 0.001). CONCLUSIONS: In this experimental setup, aortic stiffness increased after stent-graft deployment, dependent on the percentage of the aorta that was covered by stent graft. These results show that TEVAR leads to significant changes in aortic hemodynamics, which merits evaluation in the clinical setting.

Impact of thoracic endovascular aortic repair on radial strain in an ex vivo porcine model.

Objectives: To quantify the impact of thoracic endovascular aortic repair (TEVAR) on radial aortic strain with the aim of elucidating stent-graft-induced stiffening and complications. Methods: Twenty fresh thoracic porcine aortas were connected to a mock circulatory loop driven by a centrifugal flow pump. A high-definition camera captured diameters at five different pressure levels (100, 120, 140, 160, and 180 mmHg), before and after TEVAR. Three oversizing groups were created: 0-9% ( n = 7), 10-19% ( n = 6), and 20-29% ( n = 6). Radial strain (or deformation) derived from diameter amplitude divided by baseline diameter at 100 mmHg. Uniaxial tensile testing evaluated Young's moduli of the specimens. Results: Radial strain was reduced after TEVAR within the stented segment by 49.4 ± 24.0% ( P < 0.001). As result, a strain mismatch was observed between the stented segment and the proximal non-stented segment (7.0 ± 2.5% vs 11.8 ± 3.9%, P < 0.001), whereas the distal non-stented segment was unaffected ( P = 0.99). Stent-graft oversizing did not significantly affect the amount of strain reduction ( P = 0.30). Tensile testing showed that the thoracic aortas tended to be more elastic proximally than distally ( P = 0.11). Conclusions: TEVAR stiffened the thoracic aorta by 2-fold. Such segmental stiffening may diminish the Windkessel function considerably and might be associated with TEVAR-related complications, including stent-graft-induced dissection and aneurysmal dilatation. These data may have implications for future stent-graft design, in particular for TEVAR of the highly compliant proximal thoracic aorta.

Impact of Thoracic Endovascular Aortic Repair on Pulsatile Circumferential and Longitudinal Strain in Patients With Aneurysm.

PURPOSE: To quantify both pulsatile longitudinal and circumferential aortic strains before and after thoracic endovascular aortic repair (TEVAR), potentially clarifying TEVAR-related complications. METHODS: This retrospective study assessed the impact of TEVAR on pulsatile aortic strains through custom developed software and cardiac-gated computed tomography imaging of 8 thoracic aneurysm patients (mean age 71.0±8.2 years; 6 men) performed before TEVAR and during follow-up (median 0.1 months, interquartile range 0.1-5.8). Lengths of the ascending aorta, the aortic arch, and the descending aorta were measured. Diameters and areas were computed at the sinotubular junction, brachiocephalic trunk, left subclavian artery, and the celiac trunk. Pulsatile longitudinal and circumferential strains were quantified as systolic increments of length and circumference divided by the corresponding diastolic values. RESULTS: Average pulsatile longitudinal strain ranged from 1.4% to 7.1%, was highest in the arch (p<0.001), and increased after TEVAR by 77% in the arch (7.1%±2.5% vs 12.5%±5.1%, p=0.04) and by 69% in the ascending aorta (5.6±2.3% vs 9.4±4.4%, p=0.06). Average pulsatile circumferential strain ranged from 3.6% to 5.0% before TEVAR and did not differ significantly throughout the thoracic aorta; there was a nonsignificant increase after TEVAR at the unstented sinotubular junction (5.0%±1.4% vs 6.3%±1.0%, p=0.18), with a significant increase at the celiac trunk (3.6%±1.8% vs 6.2%±1.8%, p=0.02). Pulsatile circumferential strains within stented segments were deemed unreliable due to image artifacts. CONCLUSION: TEVAR was associated with an increase of pulsatile longitudinal strains (in the arch) and circumferential strains (at the celiac trunk) in unstented aortic segments. These observations suggest increased pulsatile wall stress after TEVAR in segments adjacent to the device, which may contribute to the understanding of stent-graft-related complications such as retrograde dissection, aneurysm formation, and rupture.

Computational Fluid Dynamics and Aortic Thrombus Formation Following Thoracic Endovascular Aortic Repair.

BACKGROUND: We present the possible utility of computational fluid dynamics in the assessment of thrombus formation and virtual surgical planning illustrated in a patient with aortic thrombus in a kinked ascending aortic graft following thoracic endovascular aortic repair. METHODS: A patient-specific three-dimensional model was built from computed tomography. Additionally, we modeled 3 virtual aortic interventions to assess their effect on thrombosis potential: (1) open surgical repair, (2) conformable endografting, and (3) single-branched endografting. Flow waveforms were extracted from echocardiography and used for the simulations. We used the computational index termed platelet activation potential (PLAP) representing accumulated shear rates of fluid particles within a fluid domain to assess thrombosis potential. RESULTS: The baseline model revealed high PLAP in the entire arch (119.8 ± 42.5), with significantly larger PLAP at the thrombus location (125.4 ± 41.2, p < 0.001). Surgical repair showed a 37% PLAP reduction at the thrombus location (78.6 ± 25.3, p < 0.001) and a 24% reduction in the arch (91.6 ± 28.9, p < 0.001). Single-branched endografting reduced PLAP in the thrombus region by 20% (99.7 ± 24.6, p < 0.001) and by 14% in the arch (103.8 ± 26.1, p < 0.001), whereas a more conformable endograft did not have a profound effect, resulting in a modest 4% PLAP increase (130.6 ± 43.7, p < 0.001) in the thrombus region relative to the baseline case. CONCLUSIONS: Regions of high PLAP were associated with aortic thrombus. Aortic repair resolved pathologic flow patterns, reducing PLAP. Branched endografting also relieved complex flow patterns reducing PLAP. Computational fluid dynamics may assist in the prediction of aortic thrombus formation in hemodynamically complex cases and help guide repair strategies.

Assessment of CardiOvascular Remodelling following Endovascular aortic repair through imaging and computation: the CORE prospective observational cohort study protocol.

INTRODUCTION: Thoracic aortic stent grafts are orders of magnitude stiffer than the native aorta. These devices have been associated with acute hypertension, elevated pulse pressure, cardiac remodelling and reduced coronary perfusion. However, a systematic assessment of such cardiovascular effects of thoracic endovascular aortic repair (TEVAR) is missing. The CardiOvascular Remodelling following Endovascular aortic repair (CORE) study aims to (1) quantify cardiovascular remodelling following TEVAR and compare echocardiography against MRI, the reference method; (2) validate computational modelling of cardiovascular haemodynamics following TEVAR using clinical measurements, and virtually assess the impact of more compliant stent grafts on cardiovascular haemodynamics; and (3) investigate diagnostic accuracy of ECG and serum biomarkers for cardiac remodelling compared to MRI. METHODS AND ANALYSIS: This is a prospective, nonrandomised, observational cohort study. We will use MRI, CT, echocardiography, intraluminal pressures, ECG, computational modelling and serum biomarkers to assess cardiovascular remodelling in two groups of patients with degenerative thoracic aneurysms or penetrating aortic ulcers: (1) patients managed with TEVAR and (2) control patients managed with medical therapy alone. Power analysis revealed a minimum total sample size of 20 patients (α=0.05, power=0.97) to observe significant left ventricular mass increase following TEVAR after 1 year. Consequently, we will include 12 patients in both groups. Advanced MRI sequences will be used to assess myocardial and aortic strain and distensibility, myocardial perfusion and aortic flow. ECG, echocardiography and serum biomarkers will be collected and compared against the imaging data. Computational models will be constructed from each patient imaging data, analysed and validated. All measurements will be collected at baseline (prior to TEVAR) and 1-year follow-up. The expected study period is 3 years. ETHICS AND DISSEMINATION: This study has been approved by the University of Michigan IRB. The results will be disseminated through scientific journals and conference presentations. TRIAL REGISTRATION NUMBER: NCT02735720.

Impact of Retrograde Arch Extension in Acute Type B Aortic Dissection on Management and Outcomes.

BACKGROUND: Optimal management of acute type B aortic dissection with retrograde arch extension is controversial. The effect of retrograde arch extension on operative and long-term mortality has not been studied and is not incorporated into clinical treatment pathways. METHODS: The International Registry of Acute Aortic Dissection was queried for all patients presenting with acute type B dissection and an identifiable primary intimal tear. Outcomes were stratified according to management for patients with and without retrograde arch extension. Kaplan-Meier survival curves were constructed. RESULTS: Between 1996 and 2014, 404 patients (mean age, 63.3 ± 13.9 years) were identified. Retrograde arch extension existed in 67 patients (16.5%). No difference in complicated presentation was noted (36.8% vs 31.7%, p = 0.46), as defined by limb or organ malperfusion, coma, rupture, and shock. Patients with or without retrograde arch extension received similar treatment, with medical management in 53.7% vs 56.5% (p = 0.68), endovascular treatment in 32.8% vs 31.1% (p = 0.78), open operation in 11.9% vs 9.5% (p = 0.54), or hybrid approach in 1.5% vs 3.0% (p = 0.70), respectively. The in-hospital mortality rate was similar for patients with (10.7%) and without (10.4%) retrograde arch extension (p = 0.96), and 5-year survival was also similar at 78.3% and 77.8%, respectively (p = 0.27). CONCLUSIONS: The incidence of retrograde arch dissection involves approximately 16% of patients with acute type B dissection. In the International Registry of Acute Aortic Dissection, this entity seems not to affect management strategy or early and late death.

An experimental investigation of the impact of thoracic endovascular aortic repair on longitudinal strain.

OBJECTIVES: To investigate the impact of thoracic endovascular aortic repair (TEVAR) on longitudinal strain and assess aortic tensile properties in order to better understand complications associated with TEVAR. METHODS: Twenty fresh thoracic porcine aortas were harvested and connected to a mock circulatory loop driven by a centrifugal flow pump at body temperature. Length measurements were conducted before and after TEVAR through aortic marking, high-definition imaging and custom-developed software under physiological pressure conditions (i.e. between 100 and 180 mmHg with 20 mmHg increments). Longitudinal strain was derived from length amplitude divided by the baseline length at 100 mmHg. Three groups of stent-graft oversizing were created (0-9, 10-19 and 20-29%). Finally, elastic properties of the aortic samples were assessed in both longitudinal and circumferential directions through uniaxial tensile testing. Longitudinal strain was compared before and after TEVAR, and stress-to-rupture was compared among specimens and locations. RESULTS: TEVAR induced a longitudinal strain decrease from 11.9 to 5.6% (P< 0.001) in the stented segments and a longitudinal strain mismatch between stented (5.6%) and non-stented segments (9.1%, P< 0.001). Stent-graft oversizing did not affect the magnitude of strain reduction (P= 0.77). Tensile testing showed that peak stress-to-rupture was lower for longitudinal (1.4 ± 0.4 MPa) than for circumferential fragments (2.3 ± 0.4 MPa, P< 0.001). In addition, longitudinal fragments were more prone to rupture proximally than distally (P= 0.01). CONCLUSIONS: This experimental study showed that TEVAR acutely stiffens the aorta in the longitudinal direction and thereby induces a strain mismatch, while tensile testing confirmed that longitudinal aortic fragments are most prone to rupture, particularly close to the arch. Such an acute strain mismatch of potentially vulnerable tissue might play a role in TEVAR-related complications, including retrograde dissection and aneurysm formation. The finding that TEVAR stiffens the aorta longitudinally may also shed light on systemic complications following TEVAR, such as hypertension and cardiac remodelling. These observations may imply the need for further improvement of stent-graft designs.

Contemporary Management Strategies for Chronic Type B Aortic Dissections: A Systematic Review.

BACKGROUND: Currently, the optimal management strategy for chronic type B aortic dissections (CBAD) is unknown. Therefore, we systematically reviewed the literature to compare results of open surgical repair (OSR), standard thoracic endovascular aortic repair (TEVAR) or branched and fenestrated TEVAR (BEVAR/FEVAR) for CBAD. METHODS: EMBASE and MEDLINE databases were searched for eligible studies between January 2000 and October 2015. Studies describing outcomes of OSR, TEVAR, B/FEVAR, or all, for CBAD patients initially treated with medical therapy, were included. Primary endpoints were early mortality, and one-year and five-year survival. Secondary endpoints included occurrence of complications. Furthermore, a Time until Treatment Equipoise (TUTE) graph was constructed. RESULTS: Thirty-five articles were selected for systematic review. A total of 1081 OSR patients, 1397 TEVAR patients and 61 B/FEVAR patients were identified. Early mortality ranged from 5.6% to 21.0% for OSR, 0.0% to 13.7% for TEVAR, and 0.0% to 9.7% for B/FEVAR. For OSR, one-year and five-year survival ranged 72.0%-92.0% and 53.0%-86.7%, respectively. For TEVAR, one-year survival was 82.9%-100.0% and five-year survival 70.0%-88.9%. For B/FEVAR only one-year survival was available, ranging between 76.4% and 100.0%. Most common postoperative complications included stroke (OSR 0.0%-13.3%, TEVAR 0.0%-11.8%), spinal cord ischemia (OSR 0.0%-16.4%, TEVAR 0.0%-12.5%, B/FEVAR 0.0%-12.9%) and acute renal failure (OSR 0.0%-33.3%, TEVAR 0.0%-34.4%, B/FEVAR 0.0%-3.2%). Most common long-term complications after OSR included aneurysm formation (5.8%-20.0%) and new type A dissection (1.7-2.2%). Early complications after TEVAR included retrograde dissection (0.0%-7.1%), malperfusion (1.3%-9.4%), cardiac complications (0.0%-5.9%) and rupture (0.5%-5.0%). Most common long-term complications after TEVAR were rupture (0.5%-7.1%), endoleaks (0.0%-15.8%) and cardiac complications (5.9%-7.1%). No short-term aortic rupture or malperfusion was observed after B/FEVAR. Long-term complications included malperfusion (6.5%) and endoleaks (0.0%-66.7%). Reintervention rates after OSR, TEVAR and B/FEVAR were 5.8%-29.0%, 4.3%-47.4% and 0.0%-53.3%, respectively. TUTE for OSR was 2.7 years, for TEVAR 9.9 months and for B/FEVAR 10.3 months. CONCLUSION: We found a limited early survival benefit of standard TEVAR over OSR for CBAD. Complication rates after TEVAR are higher, but complications after OSR are usually more serious. Initial experiences with B/FEVAR show its feasibility, but long-term results are needed to compare it to OSR and standard TEVAR. We conclude that optimal treatment of CBAD remains debatable and merits a patient specific decision. TUTE seems a feasible and useful tool to better understand management outcomes of CBAD.

Standardized Protocol to Analyze Computed Tomography Imaging of Type B Aortic Dissections.

PURPOSE: To propose a standard measuring protocol for type B aortic dissections so as to improve comparability between studies reporting aortic dimensions. METHODS: Fifteen computed tomography (CT) scans of type B aortic dissections were measured with a standard protocol by 2 independent observers using postprocessing software. The following parameters were assessed: true, false, and total lumen diameter; true and false lumen volume; and entry tear size, location, and number. Diameters were measured in a perpendicular plane at 2, 10, and 20 cm from the left subclavian artery and 5 cm from the most distal renal artery. True lumen volume was assessed from the left subclavian artery to the aortic bifurcation, while the false lumen volume was from the start to end up to the aortic bifurcation. Entry tear location was assessed in relation to the left subclavian artery. Intra- and interobserver repeatability and agreement were evaluated using the Bland-Altman method, an a priori set of acceptable differences, and Lin's concordance correlation coefficient (LCCC). RESULTS: Intra- and interobserver mean differences for aortic diameter and true and false lumen volumes were generally within the limits of agreement and the a priori differences; the LCCC showed excellent agreement. Entry tear location, size, and number were difficult to measure in a repeatable manner, with inconsistent correlation coefficients, especially between the 2 observers. CONCLUSION: This protocol showed acceptable repeatability for aortic diameter and aortic volume measurements. Assessment of entry tears proved challenging and associated with less favorable results. Additionally, investigators are urged to be more transparent regarding the measurement methodology used in studies describing aortic dimensions.

A review of follow-up outcomes after elective endovascular repair of degenerative thoracic aortic aneurysms.

Long-term outcomes of elective thoracic endovascular aortic repair (TEVAR) for degenerative thoracic aortic aneurysms (TAA) are not well defined. A review of the literature on the follow-up outcomes of elective TEVAR for degenerative TAA resulted in 22 relevant articles. Two- and five-year freedom from aneurysm-related death varied between 93.0% and 100.0%, and 82.4% to 92.7%, respectively. Two-year and five-year all-cause survival ranged between 68.0% and 97.2% and 47.0% to 78.0%, respectively. Follow-up ranged between 17.3 and 66.0 months. Most common endograft-related complication was endoleak, with reported rate between 1.4% and 14.8% during six months up to five years of follow-up. Endovascular reinterventions were reported in 0.0-32.3%, secondary open surgery was needed in 0.0% to 4.7% during follow-up. Aneurysm-related survival rates after elective TEVAR for degenerative TAA are acceptable. However, reported incidences of endograft-related complications vary considerably in the literature, but the majority can be managed with conservative treatment or additional endovascular procedures.

Biomechanical Changes After Thoracic Endovascular Aortic Repair in Type B Dissection: A Systematic Review.

Thoracic endovascular aortic repair (TEVAR) has evolved into an established treatment option for type B aortic dissection (TBAD) since it was first introduced 2 decades ago. Morbidity and mortality have decreased due to the minimally invasive character of TEVAR, with adequate stabilization of the dissection, restoration of true lumen perfusion, and subsequent positive aortic remodeling. However, several studies have reported severe setbacks of this technique. Indeed, little is known about the biomechanical behavior of implanted thoracic stent-grafts and the impact on the vascular system. This study sought to systematically review the performance and behavior of implanted thoracic stent-grafts and related biomechanical aortic changes in TBAD patients in order to update current knowledge and future perspectives.

Minimal-access aortic valve replacement with concomitant aortic procedure: a 9-year experience.

OBJECTIVE: Minimal-access approaches through upper hemisternotomy is an established technique for aortic valve replacement (AVR) and aortic surgery in our institution. We assessed the outcome of undergoing AVR with concomitant aortic surgery through upper hemisternotomy. METHODS: We retrospectively reviewed 109 patients from January 2002 to May 2011 who had AVR with concomitant aortic surgery through upper hemisternotomy. Aortic valve replacement with supracoronary ascending aortic replacement was performed in 65 patients; AVR with ascending and proximal arch replacement, in 8 patients; AVR with aortoplasty, in 11 patients; Bentall procedure, in 8 patients; and AVR with root enlargement, in 13 patients. In-hospital outcomes and 1- and 5-year survival were examined. RESULTS: The mean age was 58.5 years (range, 23-89 years); 41.3% of patients had bicuspid aortic valve (n = 45). Of the patients, 82.6% had true aneurysm (n = 90), 2.8% had calcified aorta (n = 3), 8.3% had small annulus (n = 9), and 3.7% had calcified annulus (n = 4). There were 6 (5.5%) reoperations and 15 (13.8%) urgent cases. Mean perfusion time was 152 ± 61 minutes, and cross-clamp time was 108 ± 47 minutes. Nine cases were performed with deep hypothermic circulatory arrest (8.3%). Operative mortality was 2.8% (n = 3). There were 4 (3.7%) cases with reoperation for bleeding, 2 (1.8%) myocardial infarctions, and 2 (1.8%) new-onset renal failure. Mean length of stay was 7.1 ± 5.6 days. Kaplan-Meier analysis showed that 1-year postoperative survival was 96.2% and 5-year survival was 92.4%. CONCLUSIONS: An upper hemisternotomy approach is safe and feasible for AVR and concomitant aortic surgery with good early and midterm outcomes. This approach is also associated with low morbidity rate and short length of stay.