Comparison of the Haemodynamic Performance of Various Treatment Options for Aorto-Iliac Occlusive Disease.

Introduction: Several surgical and endovascular techniques are used during the treatment of aorto-iliac occlusive disease. Aortobifemoral bypass (AoBFB) is the standard of care, but other options such as axillobifemoral (AxBFB) bypass, aorto-iliac kissing stents (KS), and covered endovascular reconstruction of aortic bifurcation (CERAB) are also available. This study aimed to perform a computational comparison of these four modalities to investigate their haemodynamic performance. Report: Eight patient specific anatomies were analysed, with each of the abovementioned techniques used to treat two anatomies. The CT angiograms were segmented from the renal (or axillary) to common femoral arteries and the 3D geometries were exported. A commercial finite volume solver was implemented for numerical simulations. Outcomes that were assessed were pressure drop (ΔP) between the inlet and the outlet for every configuration and haemodynamic indices of Time Average Wall Shear Stress (TAWSS), Oscillatory Shear Index (OSI), and Relative Residence Time (RRT) as markers of a thrombogenic environment. The results indicate that maximum ΔP was observed at peak systole for all models, with values ranging between 12 mmHg and 21 mmHg for the AoBFB, 64 mmHg and 96 mmHg for the AxBFB, 31 mmHg and 46 mmHg for the KS, and 43 mmHg and 46 mmHg for the CERAB configuration. TAWSS, OSI, and RRT varied among different configurations, mostly presenting values well above thrombogenic thresholds. Regarding RRT, the percentage of total surface area presenting such values is 2.5%, 3.2%, 2%, and 4.3% for the AoBFB, AxBFB, KS, and CERAB configurations, respectively. Discussion: Computational modelling indicates a favourable haemodynamic performance of AoBFB compared with the other configurations. This leads to a smaller pressure drop and sconsequently a higher pressure in the outlet of the conduit, which is the perfusion pressure of the limb. Notably, lower patency rates of the latter modalities cannot be explained based on haemodynamic indices.

Does the Routine Skin-Only Closure in Ruptured Abdominal Aortic Aneurysm Repair Safely Diminish Abdominal Compartment Syndrome? A Hypothesis Generating Retrospective Study.

BACKGROUND: Abdominal compartment syndrome (ACS) often complicates ruptured abdominal aortic aneurysm (rAAA) repair. We report results with routine skin-only abdominal wound closure after rAAA surgical repair. METHODS: This was a single-center retrospective study including consecutive patients undergoing rAAA surgical repair for the duration of 7 years. Skin-only closure was routinely performed, and if possible, secondary abdominal closure was performed during the same admission. Demographic information, preoperative hemodynamic condition, and perioperative information (ACS, mortality, rate of abdominal closure, and postoperative outcomes) were collected. RESULTS: During the study period, 93 rAAAs were recorded. Ten patients were too frail to undergo repair or refused treatment. Eighty-three patients underwent immediate surgical repair. The mean age was 72.4 ± 10.5 years, and the vast majority were male (82:1). Preoperative systolic blood pressure <90 mm Hg was recorded in 31 patients. Intraoperative mortality was recorded in nine cases. Overall in-hospital mortality was 34.9% (29/83). Primary fascial closure was performed in five patients, while skin-only closure was performed in 69. ACS was recorded in two cases in whom skin sutures were removed and negative pressure wound treatment was applied. Secondary fascial closure was feasible in 30 patients during the same admission. Among 37 patients not undergoing fascial closure, 18 died and 19 survived and were discharged with a planned ventral hernia repair. Median length of intensive care unit and hospital stay were 5 (1-24) and 13 (8-35) days, respectively. After a mean follow-up of 21 months, telephone contact was possible with 14/19 patients who left the hospital with an abdominal hernia. Three reported hernia-related complications mandating surgical repair, while in 11, this was well tolerated. CONCLUSION: Routine skin-only closure during rAAA surgical repair results in low rates of ACS at the expense of a high rate of patients being discharged with a planned ventral hernia which, however, seems to be well tolerated by the majority of patients.

Late Neck Related Adverse Events are Rare Among Patients with Wide Aortic Neck Undergoing Endovascular Aneurysm Repair with the Ovation Endograft.

BACKGROUND: Patients with wide aortic necks undergoing Endovascular Aneurysm Repair (EVAR) have been shown to be at a higher risk for neck-related complications. We aim to examine outcomes of EVAR with an endograft exerting minimal outward pressure (Ovation-Endologix) in patients with a large baseline neck diameter. METHODS: We performed a retrospective single center study, including consecutive patients undergoing EVAR with the Ovation system from May 2011 to April 2021. Patients were divided in Groups 1 and 2 if the 20, 23, 26, 29 mm or the 34 mm proximal diameter main body was used, respectively. According to the instructions for use of the device, for neck diameters 27-30 mm the 34 mm main body is required. Primary endpoint was rate of neck related complications during follow-up, (type Ia endoleak, migration >10 mm and neck-related re-interventions) and rate of aortic neck dilatation (AND). AND was determined based on multiple aortic neck diameters that were recorded and compared between the 1-month computed tomography angiography (CTA) after EVAR and the last available follow-up CTA.Secondary endpoints were peri-procedural and follow-up outcomes such as endoleaks, reinterventions and overall mortality. RESULTS: In total 281 patients were included, 222 in Group 1 and 59 in Group 2. Patients in Group 2 presented significantly shorter neck length, higher neck angulation and more common reversed tapered configuration. Median follow-up was 36 months (Range: 6-106). Early and late type Ia endoleak was observed in 4 and 2 patients in each group, respectively (P = 0.063 and P = 0.195, respectively). Distal migration was observed in 2 patients in Group 2 and AND was recorded in 2 patients in each group (P = 0.195). Freedom from the primary endpoint was estimated at 98%, 94%, 94% at 12-, 36-, 60-months for Group 1 and at 98%, 95%, 86% for Group 2 (P-Value 0.266). Probability of survival was 95%, 86%, 75% at 12-, 36-, 60-months for Group 1 and 83%, 77%, 72% for Group 2 (P-Value 0.226).Multivariate regression analysis identified neither Group 1 versus Group 2 nor absolute value of aortic neck diameter as significant predictors of neck-related adverse events. Neck diameters did not display significant differences over time in any of the levels evaluated. CONCLUSIONS: EVAR with the Ovation endograft results in low rates of late neck related complications which is also true for patients with wide baseline aortic necks.

An update on the improvement of patient eligibility with the use of new generation endografts for the treatment of abdominal aortic aneurysms.

PURPOSE: Endovascular aneurysm repair (EVAR), performed within device instructions for use (IFU), offers improved outcomes. New endograft designs attempt to increase eligibility rates of abdominal aortic aneurysm (AAA) patients treated within device IFU. We aim to examine the anatomic suitability of the Ovation endograft in our AAA patients and compare it with the other contemporary devices. RESEARCH DESIGN AND METHODS: Three-hundred and seven consecutive elective AAA patients treated during a 5-year period were included. Patient-specific anatomic characteristics were based on endograft IFUs to determine eligibility rates of each system. RESULTS: Two-hundred-twenty-five patients underwent EVAR and 82 open surgery. Ineligibility for device implantation was significantly lower for the Ovation iX system (32%) compared to other devices (AFX-2:49%, Altura:49%, Anaconda:54%, Endurant II:46%, Excluder:52%, Excluder Conformable:39%, Incraft:43%, E-Tegra:52%, Zenith-Alpha:52%; P-Value<0.001). The Alto system (next-generation Ovation) achieved an even lower ineligibility rate of 30% (P = 0.008). Short proximal aortic neck length followed by access vessel inadequacy were the primary reasons for ineligibility. CONCLUSION: The Ovation-iX included more patients with anatomic characteristics within device IFUs resulting in improved eligibility rates compared with the rest of contemporary devices. Its evolution, the Alto system, further improves patient eligibility due to the inclusion of shorter aortic necks. EXPERT OPINION: The Ovation iX system presented a significantly better performance and was eligible for use in a greater number of patients in our series of elective AAA repairs, accommodating patient-specific aortic anatomies. Of course, performing EVAR within the endograft's IFU is important to achieve optimal and durable outcomes. The proximal neck length followed by the size of the access vessels are the two more common factors resulting in loss of eligibility. Except for overall eligibility rates, a case by case decision must be made on which is the most suitable device for each patient, based on the specific characteristics of its unique anatomy.