Ann Thorac Surg 2007;83:1166-1168
© 2007 The Society of Thoracic Surgeons
Case Reports
Aortocoronary Endothelial Cell-Seeded Polytetrafluoroethylene Graft: 9-Year Patency
Davide Gabbieri, MDa,*,
Pascal M. Dohmen, MD, PhDa,
Christina Koch, MDa,
Alexander Lembcke, MDb,
Wolfgang Rutsch, MD, PhDc,
Wolfgang Konertz, MD, PhDa
a Department of Cardiovascular Surgery, Charité Hospital, Medical University Berlin, Germany
b Department of Radiology, Charité Hospital, Medical University Berlin, Germany
c Department of Cardiology, Charité Hospital, Medical University Berlin, Germany
Accepted for publication September 1, 2006.
* Address correspondence to Dr Gabbieri, Department of Cardiovascular Surgery, Charité Hospital, University Medicine Berlin, Luisenstrasse 65, D-10117 Berlin, Germany (Email: dgabbieri{at}yahoo.it).
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Abstract
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We report a 71-year old man with coronary artery disease. Complete coronary revascularization was not possible with autologous grafts; therefore, a 4-mm expanded polytetrafluoroethylene graft was implanted that had been seeded preoperatively with autologous vascular endothelial cells. At 9-year follow-up, the patient is asymptomatic and shows a patent graft.
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Introduction
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The number of patients who do not have available autologous graft material is increasing [1]; therefore, alternative conduits are needed. Prosthetic grafts have demonstrated a high risk of thrombosis and low patency rates, despite of systemic anticoagulation or antiplatelet therapy [2]. To reduce the thrombogenicity of prosthetic conduits, 4-mm expanded polytetrafluoroethylene (ePTFE) grafts were seeded with autologous vascular endothelial cells (AVEC) [1]. We report the use of an AVEC-seeded ePTFE graft to perform complete revascularization.
A 71-year-old man was referred in August 1995 to our hospital for angina pectoris. Cardiac risk factors included smoking, diabetes mellitus type 1, and arterial hypertension. His medical history was significant for inferior myocardial infarction, peripheral arterial vascular disease, chronic obstructive pulmonary disease (COPD), and bilateral postthrombotic syndrome with severe varicosis.
Transthoracic echocardiography showed a normal left ventricular ejection fraction with inferior akinesia. Coronary angiography revealed significant stenosis in the left main coronary artery, left anterior descending artery, circumflex artery, and chronic occlusion of the right coronary artery. Owing to the absence of autologous venous vessels and a positive Allen test bilaterally, the informed patient was enrolled in our protocol on AVEC-seeded grafts, which was approved by local Ethics Committee.
Graft preparation was previously reported [1]. Briefly, AVEC were harvested from a cutaneous vein in the forearm using 0.2% collagenase P (Boehringer, Ridgefield, CT). Cells were cultured in Dulbecco’s modified Eagle’s medium (Sigma, St Louis, MO) enriched with 20% autologous serum and human recombinant basic fibroblast growth factor. After 5 weeks, enough AVEC were available to seed the luminal surface of a 4-mm ePTFE (Gore-Tex, W. L. Gore & Associates, Flagstaff, AZ) precoated with a modified Tissuecol solution (Baxter, Unterschleissheim, Germany). Electronic microscopy confirmed the adherence of AVEC to the luminal wall.
Coronary artery bypass grafting (CABG) was performed according to institutional protocols. The left internal mammary artery (IMA) was placed to the left anterior descending artery, and the AVEC-seeded ePTFE graft was anastomosed to the obtuse marginal branch and to the ascending aorta with 7-0 and 6-0 polypropylene running sutures by using a "no-touch" suturing technique.
The patient’s postoperative period was uneventful, and he was discharged on postoperative day 7 with a regimen of acetylsalicylic acid at 100 mg daily. Follow-up was performed by selective angiography and intravascular ultrasonography 6 and 12 months postoperatively and then annually.
Since 2002, the patient’s AVEC-seeded graft has been investigated by using contrast-enhanced multislice computed tomography (CT). The last selective angiography from 2001 showed the patency of AVEC-seeded ePTFE graft (Fig 1) and left IMA. Intravascular ultrasound confirmed the smooth unobstructed luminal surface of the AVEC-seeded ePTFE graft. In 2004, the graft’s patency was demonstrated by multislice CT (Fig 2). Currently, the patient is in New York Heart Association (NYHA) functional class I. In 2005 and 2006, the asymptomatic patient refused further follow-up investigations.
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Fig 1. Selective angiography shows a patent expanded polytetrafluoroethylene graft seeded with autologous vascular endothelial cells after 6-years of follow-up.
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Fig 2. Multislice computed tomography shows a patent expanded polytetrafluoroethylene graft seeded with autologous vascular endothelial cells (white arrowheads) and patent left internal mammary artery (black arrowheads) after 9 years of follow-up.
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Comment
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Autologous vessels, particularly the left IMA and saphenous veins, are currently the prime choice for CABG surgery. However, up to 30% of patients lacks suitable veins owing to venous abnormality, poor quality, or previous procedures [2]. Likewise, the increasing frequency of reoperations restricts the availability of the left IMA. Despite the evolution of myocardial revascularization techniques and the progressive aging of the surgical population, complete revascularization remains a fundamental principle of CABG, increasing the quality of life and long-term survival [3].
To realize a complete revascularization, the use of additional autologous arterial grafts has steadily increased. Nevertheless, their use could be either limited or contraindicated. Because of concerns of sternal infection, dehiscence, and mediastinitis, the right IMA is avoided in elderly, obese, or insulin-dependent diabetic patients [4]. The radial artery is avoided in patients with a positive Allen test, diffuse arteriosclerosis and medial calcification, renal dysfunction, trauma to upper limbs, Raynaud disease, and recent transradial coronary angiography [5].
Potential insufficient flow in presence of coronary flow competition and vasospasm are major concerns in the use of gastroepiploic artery. Harvest of the gastroepiploic artery requires a laparotomy, and several abdominal complications have been reported. An upper abdominal malignancy represents an absolute contraindication to gastroepiploic artery harvesting, and intraabdominal adhesion owing to previous abdominal operation could result in prolonged harvesting time and accidental graft injury [6].
Complete revascularization is our goal, unless the target coronary arteries are small, severely diseased, or both. In our patient, old age and insulin-dependent diabetes mellitus were contraindications to bilateral IMA usage, and a bilateral positive Allen test recommended that radial artery harvesting be avoided. Bilateral postthrombotic syndrome with severe varicosis made the saphenous veins unsuitable. We avoid the gastroepiploic artery in patients with COPD to prevent any possible interferences of the laparotomy on the weaning from ventilatory support. Therefore, lacking autologous grafts, the possibility of incomplete revascularization was likely.
Synthetic conduits were used in CABG with poor results. The mechanisms of failure are the inherent thrombogenicity of artificial polymers and the mismatch between the rigid graft and the elastic host artery, resulting in anastomotic intimal hyperplasia and stenosis [2]. Seeding the lumen of synthetic grafts with AVEC to create a nonthrombogenic surface was first developed by Herring in 1978 [7]. Since then, AVEC-seeded synthetic grafts, 6 to 7 mm in size, have been successfully used by vascular surgeons in the treatment of peripheral vascular occlusive disease. The results clearly demonstrated that in vitro endothelialization reduces synthetic graft occlusion to a level seen in autologous vein grafts [1, 2, 8].
Encouraged by these results, we realized 4-mm AVEC-seeded ePTFE grafts suitable for CABG, and reported a 90.5% patency rate with a mean follow-up of 27.7 months [1]. Our patient was the first of our reported series, and after 108 months, the AVEC-seeded graft was patent and the patient was in NYHA functional class I.
After 2001, we were able to use multislice CT to conduct noninvasive angiographic evaluations of the AVEC-seeded ePTFE graft. This diagnostic technique showed an accuracy of approximately 90% in the detection of coronary artery disease, and an adequate diagnostic quality in the assessment of coronary artery bypass arterial and venous grafts [9].
Seeding with AVEC seems to increase the biocompatibility of 4-mm ePTFE grafts, which could represent alternative conduits in patients without autologous grafts. However, the long culture time of AVEC makes them currently an attractive proposition only in elective bypass surgery.
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References
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- Laube HR, Duwe J, Rutsch W, Konertz W. Clinical experience with autologous endothelial cell-seeded polytetrafluorethylene coronary artery bypass grafts J Thorac Cardiovasc Surg 2000;120:134-141.[Abstract/Free Full Text]
- Tiwari A, Salacinski HJ, Hamilton G, Seifalian AM. Tissue engineering of vascular bypass grafts: role of endothelial cell extraction Eur J Vasc Endovasc Surg 2001;21:193-201.[Medline]
- Kleisli T, Cheng W, Jacobs MJ, et al. In the current era, complete revascularization improves survival after coronary artery bypass surgery J Thorac Cardiovasc Surg 2005;129:1283-1291.[Abstract/Free Full Text]
- Kouchoukos NT, Wareing TH, Murphy SF, Pelate C, Marshall Jr WG. Risks of bilateral internal mammary artery bypass grafting Ann Thorac Surg 1990;49:210-219.[Abstract]
- Sajja LR, Mannam G, Pantula NR, Sompalli S. Role of radial artery graft in coronary artery bypass grafting Ann Thorac Surg 2005;79:2180-2188.[Abstract/Free Full Text]
- Hirose H, Amano A, Takanashi S, Takahashi A. Coronary artery bypass grafting using the gastroepiploic artery: 1,000 cases Ann Thorac Surg 2002;73:1371-1379.[Abstract/Free Full Text]
- Herring M, Gardner A, Glover J. A single-staged technique for seeding vascular grafts with autogenous endothelium Surgery 1978;84:498-504.[Medline]
- Deutsch M, Meinhart J, Fischlein T, Preiss P, Zilla P. Clinical autologous in vitro endothelialization of infrainguinal ePTFE grafts in 100 patients: a 9-year experience Surgery 1999;126:847-855.[Medline]
- Lembcke A, Hein PA, Dohmen PM, et al. Pictorial review: electron beam computed tomography and multislice spiral computed tomography for cardiac imaging Eur J Radiol 2006;57:356-367.[Medline]
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Abstract
Introduction
