Open Access
Open Peer Review

This article has Open Peer Review reports available.

How does Open Peer Review work?

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

  • Uwe Klima1,
  • Abdalla A Elsebaey1,
  • Mohamed R Gantri1,
  • Jochen Bongardt1,
  • Gary Miller1 and
  • Robert W Emery2Email author
Journal of Cardiothoracic Surgery20149:126

https://doi.org/10.1186/1749-8090-9-126

Received: 4 November 2013

Accepted: 16 June 2014

Published: 13 August 2014

Abstract

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.

Keywords

Vein graft patency External vein support

Background

Coronary Artery Bypass Grafting (CABG) has been shown to prolong life expectancy in patients with left main, triple vessel and/or single vessel disease with stenosis of the proximal left anterior descending artery and in those with triple vessel disease and depressed left ventricular function as well as diabetic patients [16]. Complete revascularization has long been a hallmark advantage of surgical coronary revascularization [7]. In spite of the fact that the use of bilateral internal thoracic arteries have a proven survival and decreased major adverse cardiac and cerebral events rate at out to thirty years post-CABG, the use of the saphenous vein is necessary in over 80% of surgical cases to complete revascularization [1, 8, 9]. The Achilles heel with the saphenous vein over the long term is its lower patency rate as compared to arterial grafting [10, 11]. SVG loss can be up to 50% in 10 years and is related to placing the saphenous vein, normally subject to lower venous pressures into the arterial system.

With the lack of muscular walls seen in arteries, when placed under arterial pressure, the vein dilates. Because of the acute impact of arterial pressure, damage to the endothelium can occur, resulting in the thrombus formation of and subsequent lipid deposition. Smooth muscle cells proliferate in the medial layer of the vein wall and migrate to the intimal surface a process known as neointimal hyperplasia. The resulting build up of smooth muscle cells secrete inflammatory and growth factors leading to graft stenosis and ultimate failure [12]. Further, compared to coronary arteries, saphenous veins have a larger luminal diameter resulting in a vein graft to coronary artery mismatch creating blood flow abnormalities including eddy currents and stasis. Experimentally, downsizing the SVG with an external support correlates with more arterial like healing and these grafts develop less intimal hyperplasia [13, 14]. With the concomitant resulting changes noted above, the major cause of graft failure after one month is the development of graft atherosclerotic disease and thrombosis. To address these changes the eSVS Mesh (Kips Bay Medical Inc, Minneapolis, MN) was developed.

The eSVS Mesh is an external support device that is used to downsize the vein graft of up to 35%, making a more appropriate vein to coronary artery match improving the pattern of blood flow. Also, importantly, because of the constrictive external support, expansion of the vein graft cannot occur to more than 8% of its diameter, obviating endothelial injury with the exposure to acute arterial pressure. Animal experimentation documented improved graft healing in arterial like fashion with less neointimal formation in supported grafts as opposed to unsupported grafts [1315]. A prospective randomized “first in man” feasibility trial was conducted and at the end of one year supported and unsupported grafts had equivalent patency (FDA submission). CE Mark approval was obtained in Europe. Post market studies are continuing. The object of the current study was to obtain further data as to the intermediate term (>3 month) patency in patients receiving the eSVS Mesh external support graft as a part of their coronary revascularization procedure.

Methods

The eSVS Mesh is an external support device available in three sizes which accommodates veins 3.5 to 7.0 mm when gently distended. The mesh is a highly flexible Nitinol knitted, kink resistant prosthesis into which the vein graft is inserted.

Included in the eSVS Mesh packet is a sizing tool to measure the gently distended diameter of the vein and a double wall thickness. Both of these measurements are critical in choosing the appropriate size and application of the eSVS Mesh. Veins larger than 7.0 mm and smaller than 3.6 mm and/or are too thick to fit the double wall measure should not be supported [16]. Due to radial constriction of the SVG by the eSVS Mesh, larger veins can be supported in smaller eSVS Mesh devices which are available in 3.5, 4.0 and 4.5 mm sizes.

The current study was conducted after ethics committee approval of the Medical Advisory Board and Board of Directors at the American Hospital Dubai (AHD) and individual patient written informed consent obtained. The study was conducted in accordance with the ethical principles and Declaration of Helsinki.

All patients having the eSVS Mesh as a portion of their coronary bypass grafting from October 1, 2010 through February 28, 2012 were contacted after three months or more following their procedure and were asked to return for CTA the results of which were read at AHD. The study is retrospective.

Twenty-one patients, all male, had the eSVS Mesh used on all the saphenous veins as part of their CABG over the study time frame. SVGs were harvested using an open bridging technique and all procedures were conducted on cardiopulmonary bypass with cardioplegic arrest. The eSVS Mesh was able to be deployed in all cases and there were no device related complications. No sequential grafting was performed. The grafts were determined to be patent intra-operatively using transit-time Doppler flow measurement and no revisions necessary. All patients were placed on aspirin and a statin, the dosage depending on their cholesterol level, post-operative. There was no operative mortality, re-exploration for bleeding or sternal wound infection.

Successful contact was accomplished in 20 of 21 patients (95%): All were alive and asymptomatic. One patient was unable to be contacted. Eight patients contacted by phone refused to participate in CT angiography, seven due to travel related restrictions or cost and one due to hospital administrative conflict. Those having travel restrictions were from other countries in the Middle East. Twelve patients (57%) returned for a follow-up. The eSVS Mesh was used to support all of the 26 vein grafts in these patients.

Numbers are expressed as mean +/- standard deviation.

Results

The mean age of the 12 patients returning for CTA, the crux of this report, was 57 +/- 8.8 years and all were male; the demographics of these patients is shown in Table 1. Patients had 1 to 3 grafts all supported by eSVS Mesh with a total of 26 saphenous vein grafts in addition to internal mammary artery grafting to the anterior descending coronary artery. The eSVS Mesh qualifying sizes are shown in Table 2. There was an average of 2.2 SVG per returning patient. Procedures concomitant to coronary bypass surgery were performed in 3 patients: one had thromboendarterectomy of the distal right coronary artery, one repair of an ASD and one aortic root aneurysm reconstruction. The time interval from the operative procedure to CTA was 7.2 +/- 3.7 (range = 3 to 14) months.
Table 1

Demographics on patients have eSVS Mesh supported saphenous vein graft, returning for angiography 7.2 months post-operative coronary artery bypass

Baseline history

Mean or % of subject

(N = 12)

Previous MI

50% (6)

Hypertension

75% (9)

Dyslipidemia

67% (8)

Diabetes

33% (4)

Previous CABG

8% (1)

Previous CVA

8% (1)

HX Tobacco use

 

  Current

8% (1)

  Former

50% (6)

  Never

42% (5)

CAD in 1° Relative

83% (10)

NYHA Class

 

  No/Unknown

42% (5)

  Class I

8% (1)

  Class II

17% (2)

  Class III

25% (3)

  Class IV

8% (1)

Table 2

Sizes of eSVS Mesh used to support saphenous vein grafts in patients returning for angiography 7.2 months post-operative coronary artery bypass

Qualifying device size

Number SVGs/eSVS Mesh (n = 26 grafts)

3.5

27% (7)

4.0

50% (13)

4.5

23% (6)

In the 12 patients, the eSVS Mesh supported graft was placed in the right coronary position in 9 of 12 patients (75%) and at least one supported graft was placed to the circumflex system in 92% of patients (11 of 12). Three patients had supported grafts placed to a diagonal branch of the anterior descending system. All vein grafts had only one distal anastomosis thus 35% of grafts were placed to the right system (9 of 26) and 65% in the left system (17 of 26). Patients were discharged at mean of 9.1 +/-3.9 days post-operative.Of the 12 returning patients, 11 underwent CTA in which 23 Mesh supported SVG’s (2.09 grafts/patient) were assessed. One patient having 3 supported grafts was enrolled but was unable to have CT angiography due to elevated Creatinine. He is alive and asymptomatic. CTA (N = 11) revealed that 21 of the 23 grafts were patent (patency rate = 92%). There were 2 occluded grafts, one to the right coronary artery and one to the circumflex artery. These CTAs were completed at 6 and 8 month post-operative. A representative CT scan in a patient with multiple patent supported grafts is shown in Figure 1, and an example of a patient with an occluded graft is shown in Figure 2. One patient had a stenosis of 60-70% noted in the mid-portion of a graft. The LIMA graft to the LAD was patent in all cases.
Figure 1

Representative CT angiogram in a patient multiple patent supported saphenous vein grafts.

Figure 2

Representative CT angiogram in a patient with an occluded supported saphenous vein graft.

Discussion

Use of the saphenous vein in coronary bypass surgery is necessary in over 80% of cases to assure completion of the bypass graft procedure [7]. The use of the bilateral internal mammary artery is an important aspect of coronary bypass grafting to compete with stent graft placement; however, saphenous vein grafting is still warranted in the majority of cases [1, 6, 8, 11]. Early saphenous vein patency (<1 week) is substantively improved by anti-platelet therapy delivered 1–6 hours post-operative and combined with cholesterol lowering with statin therapy improves patency to one year [17, 18]. Beyond this, no substantive impact has been made in preventing the development of vein graft atherosclerosis or improving patency. Patency of the SVG to one year is also less in smaller vessels, younger age group patients and grafts to the circumflex and right coronary systems and to those vessels with poor runoff [10, 19]. No medical therapeutic or endothelial antibody trial has improve patency beyond one year, thus the concept of external vein support is appealing [2022].

Saphenous vein graft patency at one year has been reported to be as low as 75% and at ten years 50% [11, 18] over the subsequent 10 years there is a graft loss of 1-2% per year due to the development of vein graft atherosclerotic changes [10]. The eSVS Mesh was developed to address the lower patency saphenous vein. The mesh graft supports and downsizes the SVG by up to 35% and prevents over expansion of the saphenous vein to no more than 8% of its luminal diameter thus preventing endothelial injury during acute exposure to arterial pressure. Animal experiments have documented arterial like healing of the supported grafts as compared to unsupported grafts [13, 14]. Early graft patency is dependent on the quality of the vein harvested, diameter of the coronary artery to which it is grafted, blood flow through the graft and ejection fraction. Thus, early patency may not be impacted by the eSVS Mesh as the device is designed to prevent endothelial injury and vein over distention, thus obviating the development of graft atherosclerosis over time. Genoni found that early graft patency is not negatively affected by use of the eSVS Mesh, important data when using newly implantable foreign material, assuring patient safety from potential device related complications [23].

Surgical technique can be applied using those methods of any individual surgeon: Running versus interrupted suture; proximal versus distal first; on pump or off pump revascularization. Most importantly during construction of the anastomosis, a cobra head must be created so the graft is angulated properly both at the proximal and distal end [16]. Transit-Time Doppler Flow measurement is recommended for intra-operative assessment of patency as the external support mesh does not interfere with Doppler signals [24]. Intermediate term patency data is, however, limited.

A first in man pivotal study was performed as an international multi-center randomized trial with patients receiving grafts randomized to the right and left system thus each patient served as their own control (personal communication). This study showed equivalency in patency between the supported and unsupported grafts. However, several lessons were learned from this study which may further improve the patency of supported grafts.

First, the smallest size, a 3 mm mesh was eliminated as closure rate was increased in this group and secondly, the need for an incision in the vein graft to create a cobra-head anastomosis in completion of both the proximal and the distal anastomosis is necessary to assure the each graft lies properly without kinking. Creating a cobra head for proper lie of the grafts is particularly important as those grafts constructed without this technical step had poor intermediate results [25]. Finally, accurate measurement of the vein diameter and double wall thickness were important in selecting appropriate veins to support.

Conclusion

The current study demonstrated excellent patency at 7.2 +/- 3.7 months of 92%. While there were no controls and this post-market study was not randomized, compared to the literature objective performance criteria, graft patency at this time frame is improved [18, 19]. The eSVS Mesh thus does not negatively affect early graft patency, is adaptable to varying surgical techniques and shows improvement in graft patency at the intermediate term. Further prospective randomized trials are warranted and longer term follow-up is necessary. Due to graft support and improved flow characteristics, the development of vein graft disease should be retarded and a greater impact on long term as opposed to short term patency expected. Studies are ongoing.

Abbreviations

AHD: 

American Hospital Dubai

CABG: 

Coronary Artery Bypass Grafting

CTA: 

Computerized tomographic angiography

FDA: 

Food and drug administration

SVG: 

Saphenous vein graft.

Declarations

Authors’ Affiliations

(1)
American Hospital Dubai
(2)
St. Joseph’s Hospital

References

  1. Taggert D: Surgery is the best intervention for severe coronary artery disease. BMJ. 2005, 330: 785-786. 10.1136/bmj.330.7494.785.View ArticleGoogle Scholar
  2. Mohr FW, Rastan AJ, Serruys , Kappetein AP, Holmes DR, Pomar JL, Westaby S, Leadley K, Dawkins KD, Mack MJ: Complex coronary anatomy in coronary bypass graft surgery: impact of coronary anatomy in modern bypass surgery. lessons learned from the syntax trial after 2 years. J Thorac Cardiovasc Surg. 2011, 141: 130-140. 10.1016/j.jtcvs.2010.07.094.View ArticlePubMedGoogle Scholar
  3. Morice MC, Serruys PW, Kappetein AF, Feldman TE, Stahle E, Columbo A, Mack MJ, Holmes DR, Torracca L, van Es G-A, Leadley K, Dawkins KD, Mohr F: Outcomes in patients with de novo left main disease treated with either percutaneous coronary intervention using paclitaxel – eluting stents on coronary artery bypass graft treatment in two synergy between percutaneous coronary intervention with taxus and cardiac surgery (SYNTAX). Trial Circ. 2010, 121: 2645-2653.View ArticleGoogle Scholar
  4. Serruys PW, Morice MC, Kappetein AP, Columbo A, Holmes DR, Mack MJ, Stahle E, Feldman TE, Van Den Brand MD, Bass EJ, Van Dyck N, Leadley K, Dawkins KD, Mohr F: Percutaneous coronary intervention versus coronary bypass grafting for severe coronary artery disease. N Eng J Med. 2009, 360: 961-972. 10.1056/NEJMoa0804626.View ArticleGoogle Scholar
  5. Farouh ME, Domanski M, Sleeper L, Siami ES, Dangas G, Mack M, Yang H, Cohen DJ, Rosenberg Y, Solomon SD, Desai AS, Gersh BJ, Manguson EA, Lansky A, Boineau R: Stratagies for multivessel revascularization in patients with diabetes. N Eng J Med. 2012, 367: 2375-2384. 10.1056/NEJMoa1211585.View ArticleGoogle Scholar
  6. Hee L, Mussap CJ, Yang L, Dignan R, Kadappu K, Juergens CP, Thomas L, French JK: Outcome of coronary revascularization (Percutaneous on Bypass) in patients with diabetes mellitus and multivessel coronary disease. AM J Card. 2012, 110: 643-648. 10.1016/j.amjcard.2012.04.043.View ArticlePubMedGoogle Scholar
  7. Jones EL, Weintraub WS: Surgery for acquired heart disease: the importance of revascularization during long-term follow-up after coronary artery surgery. J Thorac cardiovasc Surg. 1996, 112: 227-237. 10.1016/S0022-5223(96)70243-X.View ArticlePubMedGoogle Scholar
  8. Kurlansky PA, Traad EA, Dorman MJ, Galbut DL, Zucker M: Ebra thirty year follow-up defines survival benefit for second internal mammary artery in propensit matched groups. Ann Thorac Surg. 2010, 90: 101-108. 10.1016/j.athoracsur.2010.04.006.View ArticlePubMedGoogle Scholar
  9. Puskas JD, Sadiq A, Vassiliades TA, Kilgo DD, Latouf OM: Bilateral internal thoracic artery grafting is associated with significantly improved long-term survival, even among diabetic patients. Ann Thorac Surg. 2012, 94: 710-716. 10.1016/j.athoracsur.2012.03.082.View ArticlePubMedGoogle Scholar
  10. Goldman S, Zadina K, Moritz T, Ovitt T, Sethi G, Copeland J, Thottapurathu L, Krasnickia B, Ellis N, Anderson R, Henderson W: Long-term patency of saphenous vein and left internal mammary artery grafts after coronary artery bypass surgery. JACC. 2004, 44: 2149-2156. 10.1016/j.jacc.2004.08.064.View ArticlePubMedGoogle Scholar
  11. Sabik JF, Lytle BW, Blackstone EH, Houghtaline PL, Cosgrove DM: Comparison of saphenous vein and internal thoracic artery graft patency by coronary system. Ann Thorac Surgery. 2005, 79: 544-551. 10.1016/j.athoracsur.2004.07.047.View ArticleGoogle Scholar
  12. Motwani JG, Topol EJ: Aorto-coronary saphenous vein grafts disease: pathogenesis predisposition and prevention. Circ. 1998, 97: 916-931. 10.1161/01.CIR.97.9.916.View ArticleGoogle Scholar
  13. Zilla P, Human P, Wolf M, Lichtenberg W, Nasser R, Bezuidenhout D, Samodien N, Schmidt C, Franz T: Constrictive external nitinol meshes inhibit vein graft intimal hyperplasia in non-human primates. J Thorac Cardiovasc Surg. 2008, 136: 717-725. 10.1016/j.jtcvs.2008.02.068.View ArticlePubMedGoogle Scholar
  14. Moodley L, Franz T, Human P, Wolf MF, Bezuidenhout D, Scherman J, Zilla P: Protective constriction of coronary vein grafts with knitted nitinol. Eur J Cardiothorac Surg. 2013, 44: 64-71. 10.1093/ejcts/ezs670.View ArticlePubMedPubMed CentralGoogle Scholar
  15. Emery RW, Cooper MC, Joyce DL: Over the next hill: the inaugural arom lecture. Innov. 2012, 7: 165-172.Google Scholar
  16. Emery RW, Solien E, Jamieson SW: Implantation of the eSVS Mesh®: How To Do It. Innov. 2012, 7: 65-67. 10.1162/INOV_a_00116.View ArticleGoogle Scholar
  17. Goldman S, Copeland J, Moritz T, Henderson W, Zadina K, Ovitt T, Doherty J, Read R, Chesler , Sako Y: Improvement in early saphenous vein graft patency after coronary artery bypass surgery with antiplatelet therapy: result of a veterans administration cooperative study. Circ. 1988, 77: 1324-1332. 10.1161/01.CIR.77.6.1324.View ArticleGoogle Scholar
  18. Carrier M, Cossette M, Pellerin M, Hebert Y, Bouchard D, Cartier R, Demers P, Jeanmart H, Page P, Perrault L: Statin treatment equalizes long-term survival between patients with single and bi-lateral internal. Thoracic Artery Grafts Ann Thorac Surg. 2009, 88: 798-799.Google Scholar
  19. Kulik A, Voisine P, Mathieu P, Masters R, Mesana T, LeMay M, Ruel M: Statin therapy and saphenous vein graft disease after coronary bypass surgery: analysis from the cascade randomized trial. Ann Thorac Surg. 2011, 92: 1284-1291. 10.1016/j.athoracsur.2011.04.107.View ArticlePubMedGoogle Scholar
  20. Goldman S, Copeland J, Moritz T, Henderson W, Zadina K, Ovitt T, Doherty J, Read R, Chesler E, Sako Y: Saphenous vein graft patency 1 year after coronary artery bypass surgery and effects of antiplatelet therapy results of a veterans administration cooperative study. Circ. 1989, 80: 1190-1197. 10.1161/01.CIR.80.5.1190.View ArticleGoogle Scholar
  21. Gravaghan TP, Gebski , Baron DW: Immediate post-operative aspirin improves vein graft patency early and late after coronary artery bypass graft surgery: a placebo-controlled randomized study. Circ. 1994, 83: 1526-1533.View ArticleGoogle Scholar
  22. Goldman S, Copeland J, Moritz T, Henderson W, Zadina K, Ovitt T, Kern K, Sethi G, Sharma G, Khuri S: Long-term graft patency (3 years) after coronary artery surgery effects of aspirin: results of a va cooperative study. Circulation. 1994, 89: 1138-1143. 10.1161/01.CIR.89.3.1138.View ArticlePubMedGoogle Scholar
  23. Genoni M, Loblein O, Loblein D, Loblein H: Use of the eSVS Mesh®: External Vein Support does not Negatively Impact Early Graft Patency Submitted: Innov. JACC. 2004, 44: 2149-2156. 10.1016/j.jacc.2004.08.064.View ArticleGoogle Scholar
  24. Emery RW, Solien E: Intra-operative transit-time flow measurement is not altered in vein grafts covered by the eSVS Mesh®. In PressGoogle Scholar
  25. Schoettler J, Jussli-Melchers J, Grothusen C, Stracke L, Schoeneich F, Stohn S, Hoffmann G, Cremer J: Highly flexible nitinol mesh to encase aortocoronary vein grafts: first clinical experiments and angiographic results 9 months postoperatively. Interact J Cardiothoracic Srug. 2011, 13: 396-400.Google Scholar

Copyright

© Klima et al.; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Advertisement