Impermeability to Blood of the E-vita Open Plus Hybrid Stent-Graft: Experimental and Clinical Evaluation

Standardized in vitro bleeding tests in a non-coated novel hybrid prosthesis for frozen elephant trunk demonstrates minimal oozing during full heparinization, supported by clinical data

Introduction

Recent reports have questioned the blood impermeability of the novel frozen elephant trunk (FET) device E-vita Open NEO© (EO-NEO). Therefore, standardized in vitro bleeding tests using porcine heparinized blood were performed, as well as stress testing on the blood tightness of the collar suture line, to investigate this observation.

Material and methods

EO-NEO prostheses were examined in vitro for blood permeability in three test series. Initially, antegrade perfusion with heparinized porcine blood [activated clotting time (ACT) of 500 s, with a 60 min duration] was performed, followed by ante/retrograde testing via the EO-NEO side port. Testing of the collar suture line under a tension of 10 Newton (N) within a suspension device (blood pressure 120 mmHg, ACT of 560 s, 1 min duration) was carried out with the suture material force fiber white (FFWs) yarn, using standard fixation (5 stitches/cm), FFWh yarn in hemostatic fixation (15 stitches/cm), and flow weave yarn (FWYh).

Results

Blood permeability testing of EO-NEO through the prosthetic lumen or via the side port demonstrated minor leakage without statistical difference between the standard and hemostatic suture lines or suture materials used, or positioning on the crimped or tapered portion (p > 0.05). The specific collar anastomosis testing demonstrated leakage volumes of 140 ml/min for FFWs vs. 16 ml/min for FFWh (p = 0.02), vs. 9 ml/min with the FWYh (p = 0.01).

Conclusion

Different blood leakage tests showed minimal oozing and no difference in blood loss through the fabric and different collar suture lines, but unphysiological pressurized retrograde perfusion of the collar region showed significantly less leakage using FWYh and FFWh, prompting production modification of EO-NEO. Clinical results confirmed low blood loss using this novel FET device.

NEO E-vita—NEO era!

In this review article, the history of the first commercially available thoracic aortic hybrid graft, the E-vita Open, later modified to the blood-impermeable E-vita Open Plus, is reported from its beginning in 2005 until its newest variation, the E-vita Open NEO, European conformity (CE) marked in 2020. Besides the background of its design and clinical experience in Essen, concomitant evolutionary steps in surgery as well as in strategic approaches like the hybrid operating room concept are displayed, finally leading to a well-rounded surgical package with a device that can be applied in all elective as well as emergency situations with complex arch involving aortic pathologies. With the E-vita Open NEO, now, surgery has been facilitated to convenient anastomosing in any of the arch zones, with the opportunity to use the island technique with a straight graft variation as well as individual head vessel anastomosing with either a trifurcated graft for zone 0 or the branched graft for zone 2 or 3 implantation. With its proven long-term stability, the surgical armamentarium to cope with complex multisegmental thoracic aortic pathologies has been significantly improved.

Excessive oozing through the fabric of the branched Cryolife-Jotec Evita Open NEO hybrid prosthesis

We report 3 cases of excessive oozing after aortic arch replacement using the frozen elephant trunk technique through the fabric of the branched Cryolife-Jotec Evita Open NEO hybrid prosthesis. After weaning from cardiopulmonary bypass, protamine administration as well as standard substitution of plasmatic and cellular coagulation adjusted to thrombelastometry, excessive oozing persisted leading to a complicated postoperative course in all 3 patients.

[Hybrid grafts for aortic arch reconstruction: evolution and state of the art]

The analysis of the gained experience in treatment of patients with pathology of the arch and descending portion of the aorta is suggestive that the 'frozen elephant trunk' technique is an effective and safe method. In this connection, there is an increasing need for universal hybrid devices characterized by ease of use and durability in various aortic pathologies. Discussed in the article is the state of the art of the technology of treatment of patient with aortic arch pathology by means of hybrid grafts, followed by comparative analysis of currently used vascular hybrid prostheses, and although none of the hybrid grafts available worldwide is either universal or ideal, the grafts for the 'frozen elephant trunk' procedure continue to be improved, which will inevitably lead to wide implementation of this technique.

Open Stented Grafts for Frozen Elephant Trunk Technique: Technical Aspects and Current Outcomes

With growing experience in patients with aneurysms and dissections in the arch and proximal descending aorta, the frozen elephant trunk (FET) technique has been shown to be safe and effective, and has achieved favorable short to mid-term outcomes. As the FET technique is gaining wider acceptance, there is a growing need for versatile, technically simple, and highly durable open stented grafts involving less complicated deployment mechanisms enabling use in various indications. This paper gives a brief review on the technical aspects and clinical outcomes of currently available open stented grafts used in the FET technique, including the E-vita Open Plus, Thoraflex Hybrid, Cronus, and J Graft. While none of these grafts can claim to be an ideal device, technology continues to improve towards this goal. As newer devices and systems are developed, more widespread use of the FET technique can be expected; such progress promises to improve the clinical outcomes and quality of life for patients with complex aortic diseases.

E-vita open plus for treating complex aneurysms and dissections of the thoracic aorta: a NICE medical technology guidance

The E-vita open plus is a one-stage endoluminal stent graft system used for treating complex aneurysms and dissections of the thoracic aorta. The National Institute for Health and Care Excellence (NICE), as a part of its Medical Technologies Evaluation Programme (MTEP), selected this device for evaluation and invited the manufacturer, JOTEC GmbH, to submit clinical and economic evidence. King's Technology Evaluation Centre (KiTEC), an External Assessment Centre (EAC) commissioned by the NICE, independently critiqued the manufacturer's submissions. The EAC considered that the manufacturer had included most of the relevant evidence for the E-vita open plus, based on international E-vita open registry data for 274 patients, but had provided only limited evidence for the comparators. The EAC therefore conducted a systematic review and meta-analysis of all comparators to supplement the information, and found ten additional studies providing outcome data for the three two-stage comparators. The EAC noted that the cost model submitted by the manufacturer did not include key complications during the procedures. The EAC developed a new economic model incorporating data on complications along with their long-term costs. The revised model indicated that the E-vita open plus might not provide cost savings when compared with some of the comparators in the short-term (1 year), but would have high cost savings in the long-term, from the second year onwards. The NICE Medical Technologies Guidance MTG 16, issued in December 2013, recommended the adoption of the E-vita open plus in selected patients within the National Health Service in England.

Overall Essen's experience with the E-vita open hybrid stent graft system and evolution of the surgical technique

BACKGROUND

The hybrid stent graft prosthesis E-vita open was designed and introduced by us in 2005 to avoid a two-stage surgical approach in the surgical treatment of complex thoracic aortic disease. Experience in ascending aortic and arch replacement with simultaneous stent grafting of the descending aorta was accumulated over the past 8 years. Facilitation of surgical technique by moving the distal suture line from Zone 3 into Zone 2 took place in 2009. We report our mid-term single-center experience comparing both surgical periods.

METHODS

Between January 2005 and July 2013 a total of 132 patients (mean age 59±11 years) underwent one stage surgery for acute (AAD, n=74), chronic aortic dissection (CAD, n=35) or an extensive thoracic aortic aneurysm (TAA, n=23). Patients were separated in two groups according to distal anastomosis level in Zone 2 (Z2, 41/132) and Zone 3 (Z3, 91/132). Outcome, ischemic and operative times as well as adverse events were monitored during follow up.

RESULTS

Overall in-hospital mortality was 13% (17/132) without difference between the groups. However, Zone 2 anastomosis resulted in reduction of cardioplegic arrest (117±39 vs. 147±35 minutes; P<0.001), selective cerebral perfusion (52±15 vs. 68±18 minutes; P<0.001) and visceral ischemic time (51±19 vs. 72±23 minutes; P<0.001). The incidence of postoperative temporary hemodialysis decreased from 40% to 20% in Z2 (P=0.028), postoperative re-exploration rate from 15% to 2% (P=0.037). No difference was found in dissection with complete false lumen thrombosis in 83% (90/109) within 10 days, as well as in TAA, where 100% aneurysm exclusion was observed. Three-year survival, freedom from thoracoabdominal aortic surgery and endovascular repair was 93%, 88%, 88%, respectively. Overall 5-year survival was 76% in AAD, 85% in CAD and 79% in TAA patients.

CONCLUSIONS

The dimension of surgery could be successfully reduced, indicated by significantly shortened ischemic times and postoperative complications. Durable one-stage repair of complex thoracic aortic disease could be achieved in the majority of cases with acceptable mortality. Distal reintervention is infrequent but associated with low risk when indicated.

The past, present and future of minimally invasive therapy in endovascular interventions: a review and speculative outlook

Cardiovascular disease is a leading cause of death in all developed countries. In response to this need, endovascular management techniques have been developed across a large range of medical specialties. Minimally invasive percutaneous interventions were initially complex and challenging, but with the continued development of equipment and expertise their use has become routine in many fields. With routine use, it has become important to establish the safety and efficacy of endovascular treatments against the respective "gold standard" procedures, especially in light of their initial intended use for the management of patients at unacceptably high risk for standard therapy only. Such evaluation has to take into account the variety and diversity of devices and techniques, as well as the effects of operator dependability. Endovascular techniques are increasingly recognised as valid alternative management options for a variety of conditions, and it is anticipated that the current trend towards minimally invasive techniques will continue in the future, with moves towards increasingly complex endovascular techniques and hybrid interventions.