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Clinical evaluation of the eSVS Mesh: First-in-Man trial outcomes

In coronary artery bypass graft surgery, saphenous vein graft (SVG) patency is much lower than that of the internal mammary artery (IMA). To address this problem, an external support device, the eSVS Mesh was developed. A prospective randomized First-in-Man feasibility trial was conducted in 90 patients after institutional ethics committee approval at seven international centers. The left IMA was used to bypass the anterior descending artery. A mesh-supported (treated) saphenous vein was randomized to either the right or the circumflex coronary system, and an unsupported (control) vein was grafted to the opposing territory. Device diameters available for use were 3.0, 3.5, 4.0, and 4.5 mm. Primary end-points were 30 day adverse cardiac and cerebral events and angiographic patency at 9-12 months. Eighty-five of 90 patients returned for 30 day clinical follow-up (94%). Five patients refused to return, but by telephone contacts were asymptomatic. There was one late noncardiac death and 73 patients returned for angiography (82%), thus 12 additional patients were lost to follow-up at 1 year. Overall patency rate was 49% for the treated versus 81% for controls (p < 0.001). Subset analysis revealed significantly lower patency at one center and with use of the 3.0 mm device (p < 0.05). Removing these data, patency was 72% vs. 81% (p = NS). Sternal wound infection was higher than expected at 5.0%, but this was center specific. The eSVS Mesh is safe, but at up to 1 year, patency is equivalent to untreated vein grafts after removal of outlying data. This study provides insight into operative events and parameters that may optimize outcomes and point to potential improvements in the external SVG support device. Furthermore, longer term studies are pending.

External Saphenous Vein Support Mesh Does Not Interfere With Transit-Time Flow Measurement on Venous Coronary Bypass Conduit: Clinical Confirmation

A 65-year-old patient underwent double coronary artery bypass grafting using the left internal thoracic artery on the left anterior descending coronary artery and nitinol alloy mesh [external Saphenous Vein Support (eSVS)]-covered saphenous vein graft to the right posterior descending coronary artery. Transit-time flow measurements (TTFMs) were obtained on meshed and bare parts of the vein graft. There was no difference in TTFM parameters (flow, pulsatility index, and diastolic fraction values) obtained from the eSVS mesh-covered and the uncovered parts of the venous graft. This observation confirms that eSVS mesh does not interfere with TTFM on venous coronary bypass conduits.

Implantation of the eSVS Mesh: modification of recommended technique

The eSVS Mesh is a knitted wire lattice manufactured in cylindrical sheaths of various diameters, designed to be placed around the outer surface of a saphenous vein graft before use in coronary surgery. The goal is to improve long-term vein graft patency by preventing expansive endothelial injury obviating neointimal hyperplasia and subsequent graft atherosclerosis. Since the First-In-Man feasibility trial of the eSVS Mesh, postmarket studies in Europe and a feasibility trial in the United States are ongoing. Consensus from the principal investigators indicated the trials had confounding variables that may impact results other than evaluation of the eSVS Mesh alone. With input from these investigators, the recommended operative technique has been modified for future trials by removing the mesh from proximal and distal anastomoses and eliminating the use of fibrin sealant. These changes allow for use of an implant technique closer to standard vein bypass grafting and a more focused evaluation of the eSVS Mesh.

Computerized tomographic angiography in patients having eSVS Mesh(R) supported coronary saphenous vein grafts: intermediate term results

Background

The Saphenous Vein (SVG) is used in over 80% of coronary artery bypass procedures (CABG) and SVG patency is the Achilles heel of CABG. To address this issue, the eSVS Mesh®, an external Nitinol knitted mesh, fitted like a sleeve over the vein graft preventing over expansion in the high pressure arterial system, has been introduced to improve disease management. Patency data is limited. The objective of this retrospective study is to report patency rates (>3 months) in patients having external mesh support as part of CABG.

Methods

From October 25, 2010 through February 13, 2012, 21 patients had external mesh support of SVG grafts in addition to internal thoracic artery grafting to the Anterior Descending artery. Patients were invited to return for patency evaluation using Computerized Tomographic angiography (CTA) an average of 7.2 months post-operative (R = 3-14 months).

Results

21 male patients (age 57 +/- 9 years) underwent on-pump surgery. The eSVS Mesh was successfully placed on all SVGs. All grafts were determined patent intra-operative by transit time Doppler measurement and there were no operative revisions. There was no operative mortality. 12 of the 21 contacted patients returned for CTA, 8 non-returning patients contacted were alive and asymptomatic but refused to return due to travel restrictions or cost. One patient was lost to follow up. 11 returning patients underwent CTA. One patient was excluded (asymptomatic) due to elevated creatinine. Of the 23 anastomoses in 11 patients (Average: 2.09 grafts/patient) using SVG available for examination, 21 were patent (92%).

Conclusions

In this retrospective non-randomized experience, the external mesh supported grafts displayed excellent intermediate patency.

Electronic supplementary material

The online version of this article (doi:10.1186/1749-8090-9-126) contains supplementary material, which is available to authorized users.

Intraoperative transit-time flow measurement is not altered in venous bypass grafts covered by the eSVS mesh

OBJECTIVE

The aim of this study was to determine whether the eSVS Mesh interferes with transit-time flow measurement (TTFM) assessing intraoperative coronary vein graft patency.

METHODS

In four swine undergoing off-pump bypass grafting to the anterior descending coronary artery, five TTFMs were sequentially obtained on meshed and bare grafts at baseline and under Dobutamine stress at five separate locations on the graft in each animal. The Medistim VeriQ was used for TTFM. The grafts were examined for patency after the swine were killed.

RESULTS

There was no difference in hemodynamics or TTFM either at baseline or under Dobutamine stress between the eSVS Mesh covered and uncovered grafts. Dobutamine, however, significantly increased hemodynamics and graft flow parameters measured from baseline.

CONCLUSIONS

The eSVS Mesh does not interfere with Doppler flow measurement in covered coronary vein grafts.