Unibody Graft Research Articles

Elective Endovascular Repair of Abdominal Aortic Aneurysms with Modular and Unibody Type Endografts.

In this study, we aimed to evaluate the performance of modular and unibody endografts for the endovascular repair of abdominal aortic aneurysm (AAA). Between January 2012 and December 2017, 130 elective infrarenal abdominal aortic aneurysms treated in an endovascular manner were retrospectively evaluated. Sixty-six patients with the modular type (Medtronic EndurantTM II and Lifetech AnkuraTM AAA) and 64 patients with the unibody type (Endologix AFX®) were compared with regards to early and postoperative one-year results. There was one in-hospital mortality (0.8%) in the modular group. There was no difference in postoperative first-year mortality rate between the two groups (p = 0.678). Loco-regional anesthesia was used more often in the unibody group [34 patients (53.1%)] and the use of general anesthesia was higher in the modular group [56 patients (84.8%)] (p < 0.001). While the duration of the procedure was shorter in the unibody group (p < 0.001), no statistically significant difference was found in the duration of fluoroscopy (p = 0.813) and the amount of contrast agent used (p = 0.553). The follow-up period in the intensive care unit was shorter in the modular group (p < 0.001). Moreover, the five-year survival rate was similar between the groups (84.8% in the modular group and 78.4% in the unibody group, log-rank p = 0.703). The results obtained in our study show that modular and unibody grafts are effective and reliable, although there are some negligible differences in the early period.

Twenty years outcomes in a single center experience after endovascular aneurysm repair with unibody endograft and anatomical fixation.

To assess the long-term safety and effectiveness of endovascular aneurysm repair (EVAR) treatment with unibody endograft deployed on aortic bifurcation (anatomical fixation). A retrospective, observational, single-center study of patients treated from 1999 to 2002 with unibody bifurcated endograft. Follow-up protocol required clinical and doppler-ultrasound at 1 and 6 months and annually thereafter, computed tomography angiography at 1-, 6- and 12-months and then every year. Primary endpoints included technical and treatment success, survival and freedom from late EVAR failure; secondary endpoints were freedom from late open conversion (LOC), freedom from late re-interventions and endoleaks. Seventy-three patients, mean age of 73±6 years were enrolled. Median follow-up was 6±0.5 years. Technical success was 98.6% (N.=71/73; causes of failure: 1 open conversion and 1 type Ib endoleak). A treatment success of 96% (N.=69/72) was recorded due to endoleaks (N.=2; 1 type Ia and 1 type Ib) and limb occlusion (N.=1). Survival at 1, 5, 10, 15 and 18 years was 90%, 58%, 40%, 32% and 23% respectively. One aneurysm-related death for infection of the endograft was registered. EVAR failure was 14% (N.=10/71). Three LOC were recorded and freedom from reinterventions at 1, 5, 10 and 18 years was 99%, 91%, 86% and 86%. Fourteen endoleaks were recorded: Ia (N.=6; 42.8%), Ia+Ib (N.=1; 7.1%), Ib (N.=2; 14.2%) and II (N.=5; 35.6%). Four endoleaks were observed, 9 endovascular correction and 1 LOC were required. Endoleaks free survival of 90% at 1-year and 75% at the end of the study. Aneurysm sac shrinkage was observed in 79% (N.=56/71). This small, retrospective cohort of anatomically fixed EVAR demonstrated long-term safety and effectiveness. The design of the unibody graft did not substantially change and newer generation should guarantee the same performance.

Comparison of Endovascular Stent Grafts for Abdominal Aortic Aneurysm Repair in Medicare Beneficiaries

Increased renal complications have been suggested with suprarenal stent grafts, but long-term analyses have been limited. Therefore, the purpose of this study was to evaluate the effect of endograft choice on perioperative and long-term outcomes. We compared Medicare beneficiaries undergoing endovascular abdominal aortic aneurysms repair from 2005 to 2008 with endografts with infrarenal fixation and a single docking limb (AneuRx, Excluder) to those with suprarenal fixation and 2 docking limbs (Zenith), or a unibody configuration (Powerlink). Propensity score weighting accounted for differences in patient characteristics among the different graft formations, and perioperative mortality, complications, and length of stay and 4-year rates of survival, rupture, and reintervention were compared. Forty-six thousand one hundred seventy-one Medicare beneficiaries were identified including 11,002 (24%) with suprarenal fixation, 32,909 (71%) with infrarenal fixation, and 2,260 (5%) with a unibody graft. After propensity score weighting, there were no significant differences in patients' baseline clinical and demographic characteristics. The suprarenal fixation patients had higher rates of perioperative mortality (1.7% vs. 1.3%, P<0.01), renal failure (6.0% vs. 4.7%, P<0.001), and mesenteric ischemia (0.7% vs. 0.4%, P<0.01) and longer length of stay (3.4days vs. 3.0days, P<0.001) compared with patients with infrarenal fixation. Unibody grafts had higher rates of renal failure (5.9% vs. 4.7%, P<0.001), mesenteric ischemia (1.0% vs. 0.4%, P<0.001), and conversion to open repair (0.7% vs. 0.1%, P<0.001) compared to those with infrarenal fixation and single docking limbs. At 4 years, mortality remained slightly higher with suprarenal compared to infrarenal fixation (30% vs. 29%, P=0.047), although these patients had fewer conversions to open repair (0.6% vs. 0.9%, P=0.03) and aneurysm-related reinterventions (10% vs. 12%, P<0.01). At 4 years, unibody grafts had more aneurysm-related interventions compared to infrarenal fixation grafts (15% vs. 12%, P<0.01) but fewer conversions to open repair (0.4% vs. 0.9%, P=0.02). Late rupture did not differ among the groups. Compared to infrarenal fixation devices, patients who underwent EVAR with suprarenal fixation had higher perioperative mortality and renal complications but fewer reinterventions including conversion, while the unibody graft had more perioperative complications and aneurysm-related reinterventions, but fewer conversions to open repair. Although these differences could be explained by selection bias, these data suggest that further comparative effectiveness analyses should be performed to understand the outcomes following EVAR with suprarenal fixation and unibody grafts.

Part Two: Against the Motion: It is not necessary to perform a randomised trial to compare open and endovascular repair of ruptured abdominal aortic aneurysms

anticipated from the literature. Irrespective of the reports of the good outcomes after endovascular repair from single expert centres or administrative databases, all these results are heavily confounded by patient selection and risks are under-reported. We need better evidence to guarantee the best outcomes for future patients with aneurysm rupture. We need to know whether an attempt at endovascular repair would be beneficial for all patients. It is only such knowledge that will drive changes in the provision of healthcare services to benefit future patients. The front cover of the Lancet issue of 26th September 2009, which published the IDEAL statements, carried this sentence: “It is incumbent on academic surgeons worldwide to transform what was once considered a comic opera into a dynamic world-class specialty”. We need to assess surgical innovations, including endovascular repair for ruptured aneurysm, rapidly in large, pragmatic RCTs.

Initial management and outcome of aortic endograft limb occlusion

The purpose of this study was to determine the differences in outcome related to initial management of aortic endograft limb occlusion (ELO). During a 7-year period, 823 endovascular aneurysm repairs (EVARs) resulted in 25 ELOs in 22 patients. The initial management and outcome of these ELOs were reviewed. Median follow-up after ELO was 24.2 +/- 16.8 months. Initial EVARs included both unsupported unibody (n = 5) and supported modular (n = 17) devices. ELO was significantly more common in the unsupported unibody graft design (P <.024) and with extension of the graft limb to the external iliac artery (P <.001). ELO was managed with an endovascular approach (EVA), including some combination of mechanical thrombectomy (n = 8), angioplasty with or without stenting (n = 8), and thrombolysis (n = 2) in 12 patients and bypass procedures (femoral-femoral bypass, n = 11; axillofemoral bypass, n = 1; and aortofemoral bypass, n = 1) in 13. At 12-month follow-up, freedom from secondary procedures with EVA was 80.2 +/- 17.7% versus 53.2 +/-17.1% with extra-anatomic bypass (EB) (P = NS). Secondary patency was 100% with EVA and 80.6 +/- 14.4% with EB (P = NS). Of the 12 EVAs, there was 1 (8.3%) perioperative mortality with EVA and none with EB. EB failure was directly attributed to donor limb occlusion in 4 of 6 EVAs (67%), and when this occurred it resulted in bilateral lower extremity ischemia. Amputation was required in 2 of 12 (16.7%) EBs versus none of the 12 EVAs (P = NS). EVA never resulted in graft dislodgement or endoleak but did identify an underlying treatable cause in 8 of 12 (67%). Both EVA and EB are acceptable management strategies for ELO. The potential risk of graft dislodgement was not observed with an EVA. If EB is employed, assessment of the donor limb and treatment of any underlying lesions is advisable in an attempt to minimize future donor limb occlusion.

Which Industry-Made Endovascular Grafts Are Best for Abdominal Aortic Aneurysm Repair and Why?

Main complications in endovascular abdominal aortic aneurysm (AAA) repair are endoleaks and limb occlusion. An analysis of our data showed that this technique is no longer an experimental procedure. The new generation of endovascular grafts has been improved. Unibody grafts and nonstented tube grafts in our series show better results than modular systems and stented tubes.