Konstantinos C. Kapoulas

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.

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.

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.

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.

Expanding Current EVAR Indications to Include Small Abdominal Aortic Aneurysms: A Glimpse of the Future:

The traditional criterion of maximum transverse diameter is not sufficient to differentiate the small abdominal aortic aneurysms (AAAs) that are either prone to rupture or prone to enlarge rapidly. Wall stress may be a more reliable indicator with respect to these tasks. We review the importance of geometric features in rupture- or growth-predictive models and stress the need for further evaluation and validation of geometric indices. This study may lead to identifying those small AAAs that could justify early endovascular intervention.

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.

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.

Antiplatelet Treatment and Prothrombotic Diathesis Following Endovascular Abdominal Aortic Aneurysm Repair

Prothrombotic diathesis expressed by elevated levels of coagulation-specific biomarkers has been reported in patients with abdominal aortic aneurysm (AAA) and after AAA endovascular repair (EVAR). This study investigates the effect of antiplatelet agents (APLs) on the prothrombotic diathesis in the post-EVAR period. Forty elective EVAR patients had thrombin–antithrombin complex, d-dimer, fibrinopeptide A, and high-sensitivity C-reactive protein measured before, at 24 hours, 1 month, and 6 months after EVAR. Patients receiving APLs postoperatively were compared with those not receiving APLs. All biomarkers were above the normal limits preoperatively and increased significantly 24 hours postoperatively followed by a drop at 1 and 6 months. No statistically significant changes were noted among patients receiving APLs in comparison with those not receiving APLs. The preoperative and postoperative prothrombotic diathesis of AAA following EVAR was confirmed in line with other reports. There was however no significant alteration of the examined biomarkers in patients receiving APLs.

An uncommon clinical presentation of acute limb ischemia: underscoring the role of perigenicular collaterals.

We present a case of atypical acute limb ischemia in a non-diabetic patient, with ankle–brachial pressure index of 0.6 and rest pain localized exclusively over the gastrocnemius muscle, sparing the foot. This uncommon presentation was attributed to an impaired perigenicular collateral network. Thrombolysis restored adequate perfusion only temporarily and was followed by thromboembolectomy. The ischemia presentation in our case underscores the importance of the adequacy of the perigeniculate collateral network for the perfusion of the tibial muscles and, especially, the gastrocnemius muscle.

Overcoming the venous outflow obstruction in true venous aneurysms of arteriovenous fistulae can lead to aneurysms’ remodeling and shrinking

declined further after six months. The creation of a new venous drainage pathway, either by transposing the cephalic/basilic vein or even recruiting the deep venous system of the upper arm, has been reported as a means to preserve a failing AVF (3-5), but never in order to reduce the flow resistance proximal to a venous aneurysm. The aforementioned intra-operative management provided us with an interesting finding and implication, that of the potential Overcoming the venous outflow obstruction in true venous aneurysms of arteriovenous fistulae can lead to aneurysms’ remodeling and shrinking