Lessons Learned from Open Surgical Conversion after Failed Previous EVAR.

BACKGROUND: Delayed open conversion (OpC) after endovascular aortic aneurysm repair (EVAR) is becoming increasingly common worldwide. We reviewed our experience to characterize the perioperative spectrum of OpC repairs. MATERIALS AND METHODS: A retrospective analysis of a prospectively maintained institutional database to identify patients who underwent late OpC after failed EVAR was performed. Patient and aneurysm baseline characteristics, mechanism of failure, perioperative details, including type of repair/complications/survival, and late outcomes were examined. RESULTS: From January 2003 to January 2020, 38 male patients (mean age, 75 ± 7 years; range, 60-90) required late OpC. Interval time from initial EVAR to OpC was 63.6 ± 33.8 months (range, 17-120). Mean diameter of the aneurysms was 82.2 ± 22.1 mm before OpC compared with 62.9 ± 13 mm before endograft implantation. Mechanisms of failure were type Ia, Ib, II, and III endoleaks in 14 (36.8%), 9 (23.7%), 4 (10.5%), and 1 (2.6%) patient(s), respectively; infection in 3 (7.9%), leg ischemia in 2 (5.3%), and multiple causes in 5 (13.2%) patients. We observed 4 (10.5%) asymptomatic, 16 (42.1%) symptomatic, and 18 (47.3%) ruptured aneurysms. Four patients (10.5%) had stable contained ruptures, whereas the remaining 13 (34.2%) and 1 additional patient (2.6%) with aortoenteric fistula presented with hemorrhagic shock (class ≥II). Total endograft explantation, endograft preservation, or proximal/distal partial graft removal was performed in 16 (42.1%), 10 (26.3%), and 2 (5.2%)/9 (23.7%) of patients, respectively. Technical success was 100%, excluding an early postaortic clamping death. Overall, 30-day mortality was 21.1% (8 of 38) and significantly higher in patients with hemorrhagic shock or hemodynamic instability at presentation (P = 0.04 and P = 0.009, respectively) and in patients who had endografts with hooks/barbs or experiencing higher postoperative complication rate (P = 0.02 and P = 0.006, respectively). By definition, procedure success was 81.1%. Mean follow-up was 37.6 ± 39.8 months. By the end of the study, we recorded 11 deaths (2 were aneurysm related). CONCLUSIONS: Despite high technical success, OpC has a significant mortality in patients presenting with hemorrhagic shock and had active fixation endografts or experiencing high complication rate. Many other confounding factors may play a role.

Aneurysm sac shrinkage after endovascular treatment of the aorta: beyond sac pressure and endoleaks.

The isolation of the aneurysm sac from systemic pressure and its consequent shrinkage are considered criteria of success after endovascular repair (EVAR). However, the process of shrinkage does not solely depend on the intrasac pressure, the predictive role of which remains ambiguous. This brief review summarizes the additional pathophysiological mechanisms that regulate the biomechanical properties of the aneurysm wall and may interfere with the process of aneurysm sac shrinkage.

Early results of the Endurant endograft system in patients with friendly and hostile infrarenal abdominal aortic aneurysm anatomy.

OBJECTIVE: To evaluate and compare the outcome after endovascular abdominal aortic aneurysm repair (EVAR) with the newly released Endurant endograft system in patients with different aortoiliac anatomic characteristics. METHODS: We conducted a prospective observational study assigning patients with infrarenal abdominal aortic aneurysm (AAA) treated with the Endurant endoprosthesis from February 2009 to March 2010. Two groups were studied, according to the presence of a friendly (group I [GI] = 43) or hostile (group II [GII] = 34) infrarenal aortoiliac anatomy. Hostile profile was defined as any (or combination) of the following measurements: 5 mm ≤ proximal neck length (Lpr) ≤ 12 mm, 60° < proximal neck angle (A°pr) ≤ 90° and 60° < any iliac axis angle (A°iliac) ≤ 90°. Primary end points included technical and clinical success, freedom from early or late secondary interventions, any type of endoleak, and aneurysm-related death. All outcome measures were calculated using the Kaplan-Meier method and the log rank test was applied for comparisons between the groups. RESULTS: The mean comorbid severity scoring was higher in GII (P = .018). The mean follow-up period in GI and GII was 12.9 ± 3.9 months (± SD, range: 6.4-19.8) and 12.4 ± 4 months (range: 4.2-19.6), respectively. Two unplanned conversions to aortouniiliac configurations were required in GI. The technical success rate in GI and GII was 95.4% and 100%, respectively. The requirement for intentional occlusion of the internal iliac artery, the requirement for cross-limb technique, the necessity of troubleshooting techniques, the procedure and radiation times, the frequency of postimplantation syndrome, and mean hospital stay were significantly higher in GII (P = .028, P = .013, P = .005, P = .037, P < .001, P = .032, P = .021, respectively). Two patients of GI died in the early postoperative period (one aneurysm but not device-related death), whereas no deaths in GII were recorded, yielding an overall 30-day mortality rate of 2.3%. No type I/III endoleaks were recorded up to the end of the study. Freedom from any type of endoleak, early or late secondary interventions, and aneurysm-related death at 12 months were found in 93.2%, 87.1%, and 93.3% of GI patients; respective values for GII were 86% (P = .21), 93.4% (P = .066), and 93.4%. The clinical success rate was 82.1% and 100% at 12 months for GI and GII, respectively. CONCLUSIONS: Early (12 months) results suggest similar clinical performance of the Endurant stent graft system in endovascular treatment of AAAs with friendly and hostile anatomies, however, demonstrating more intra- and perioperative adversities for the last group. Larger prospective studies or even randomized trials comparing different new generation graft models are required to evaluate the comparable long-term results and possible expansion of EVAR indications for this specific endograft in adverse anatomies.

Emergency endovascular treatment of early spontaneous nonaneurysmal popliteal artery rupture in a patient with Salmonella bacteremia.

Rupture of a nonaneurysmal popliteal artery and subsequent pseudoaneurysm formation is an exceedingly rare event after bacteremia caused by Salmonella spp. Only a few cases have been reported in the literature. Moreover, spontaneous popliteal artery rupture resulting from this pathology, to our knowledge, has not been reported. We describe an early spontaneous rupture of the popliteal artery complicated by acute compartment syndrome in a 67-year-old man who had recently experienced fever, chills, and diarrheal syndrome and had sustained episodes of bacteremia infection, with isolation of S enteritidis. Immediate endovascular sealing of the bleeding site was achieved with a covered stent, and his recovery was uneventful. The long-term durability of endovascular repair in this type of pathology remains to be determined, however.

A computational study of the factors influencing pressure in arteriovenous fistulae venous aneurysms.

PURPOSE: To investigate the factors influencing the hydrostatic pressure exerted within the venous aneurysms (VA) of an arteriovenous fistula (AVF). METHODS: Ideal models of a side-to-end brachial-cephalic AVF were computationally constructed and typical values for the length and the local diameters were considered for both the artery and vein sections of the models. Three VA configurations were reconstructed (spherical, fusiform and curved) and hydrostatic pressure was assessed with respect to different degrees of the outflow vein stenosis, ranging from 25% to 95%, and VA maximum diameters, using validated, commercially available software. RESULTS: The pressure in the VA was steady (1200 Pa) for venous outflow stenoses up to 75%. For stenoses greater than 75% a exponential pressure rise was observed, reaching 1500 Pa for stenoses of 95%. Neither the VA configuration nor its maximum diameter affected the pressure values exerted within the VA or the point of the pressure upstroke. CONCLUSIONS: our study supports the presence of a critical stenotic outflow vein diameter beyond which there is an exponential VA pressure increase, influenced neither by the shape nor the size of the VA. Whether the prompt, non-invasive detection of this finding can contribute or lead to the determination of a criterion for early intervention in VAs before clinical complications are developed, should be investigated by future studies.

Modification of the trap door technique to treat venous aneurysms in arteriovenous fistulae.

We present a modification of the "trap door" technique to treat true venous aneurysms which complicate vascular access arteriovenous fistula. The technique provides wide exposure of the aneurysm, facilitating aneurysmoraphy and permitting the exploitation of any adequate venous length for autologous reconstruction of the venous outflow. Furthermore, by precluding the proximity of the newly-reconstructed venous segments to the incised skin, their level of compromise from tissue scarring or infection is prevented.

Application of bioengineering modalities in vascular research: evaluating the clinical gain.

Using knowledge gained from bioengineering studies, current vascular research focuses on the delineation of the natural history and risk assessment of clinical vascular entities with significant morbidity and mortality, making the development of new, more accurate predictive criteria a great challenge. Additionally, conclusions derived from computational simulation studies have enabled the improvement and modification of many biotechnology products that are used routinely in the treatment of vascular diseases. This review highlights the promising role of the bioengineering applications in the vascular field.

An overview of the hemodynamic aspects of the blood flow in the venous outflow tract of the arteriovenous fistula.

Upper limb vein aneurysms complicate all types of autogenous arteriovenous fistulae (AVF) and comprise false aneurysms secondary to venipuncture trauma as well as true aneurysms, characterized by dilatation of native veins. The dilatation of a normal vein and the development of a true aneurysm are strongly influenced by local hemodynamic factors affecting the flow in the drainage venous system and are also the target of operative interventions. This review article focuses on the description of these hemodynamic aspects which all physicians involved in the management of dialysis patients should be aware of. Furthermore, it delineates their complicated interactions and also highlights their utility in clinical decision-making and therapeutic management.

Composite PTFE-transposed superficial femoral vein for lower limb arteriovenous access.

PURPOSE: We report our experience in creating a composite loop of transposed superficial femoral vein (tSFV) and polytetrafluoroethylene (PTFE) synthetic graft for lower limb access. The indication for surgery was exhaustion of access sites in both upper limbs. METHODS: Surgery was performed on 3 male patients. All patients had an ankle brachial index =0.9. The SFV was mobilized up to adductor canal, with ligation of all small tributary branches, up to the level below the profunda femoral vein, then tunneled medially to the skin. A 6-mm PTFE graft was tunneled laterally, deep in the subcutaneous plane in loop fashion to the end of the tSFV, where a beveled end-to-end anastomosis was created. RESULTS: The blood flow in both fistulas increased gradually to 0.7-1.3 l/min postoperatively. No clinical manifestation indicative of lower limb ischemia, lymphorrhea, or infection was documented. No signs related to chronic venous hypertension were noticed. CONCLUSIONS: Our initial experience shows that the creation of a composite PTFE-tSFV conduit is a promising technique, since it can be constructed without compromising the distal perfusion, and without infectious complications.