Ann Thorac Surg 1996;62:691-695
© 1996 The Society of Thoracic Surgeons
Original Articles: Cardiovascular
North American Experience With the Perma-Flow Prosthetic Coronary Graft
Robert W. Emery, MD,
Noel L. Mills, MD,
F. Javier Teijeira, MD, PhD,
Kit V. Arom, MD, PhD,
Pam Baldwin, RN,
Rebecca J. Petersen, RN,
Lyle D. Joyce, MD, PhD,
George L. B. Grinnan, MD,
Marc S. Sussman, MD,
Jack G. Copeland, III, MD,
John L. Ochsner, MD,
Steven W. Boyce, MD,
Demetre M. Nicoloff, MD, PhD
Minneapolis Heart Institute, Minneapolis, Minnesota; West Jefferson Medical Center, New Orleans, Louisiana; Norfolk General Hospital, Norfolk, Virginia; The Johns Hopkins Medical Center, Baltimore, Maryland; The University of Arizona, Tucson, Arizona; The Oschner Clinic, New Orleans, Louisiana; University De Sherbrooke, Sherbrooke, Quebec, Canada; and Washington Hospital Center, Washington, DC
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Abstract
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Background. The Perma-Flow prosthetic coronary graft is a 5-mm polytetrafluoroethylene tube into which is incorporated a Venturi flow restrictor. An aorto-superior vena caval fistula is created and coronary anastomoses are constructed proximal to the resistor in side-to-side fashion, where arterial pressure is maintained. From November 1992 through December 1995, eight investigational centers in North America have implanted this graft in 40 patients with inadequate autologous alternatives.
Methods.Patients were selected for inclusion in this study if coronary artery bypass grafting was required and adequate autologous conduit to complete revascularization was not available. Operative data were completed by the implantating surgeon and referred to a central center, the Minneapolis Heart Institute, for correlation. Follow-up was conducted by data coordinators at each institution, and follow-up data were obtained directly from these coordinators for inclusion in the study.
Results.Patient age ranged from 53 to 82 years, and 15 patients were undergoing reoperations (38%). On each Perma-Flow graft one to four coronary side-to-side anastomoses were constructed. In addition, left internal mammary artery (n = 26), greater saphenous vein (8), right internal mammary artery (4), and gastroepiploic artery (4) were used to complete revascularization. Aortic (2) or mitral valve replacement (1) was also carried out. There were seven operative deaths (18%) and two late deaths (4 and 6 months). After 1 to 37 months (mean, 13 ± 9 months) of follow-up, 29 of 31 surviving patients are asymptomatic. Echocardiographic heart size has not increased from the postoperative value, indicating limited volume load has not affected heart size. Protocol catheterization (n = 32) in 28 patients 1 week to 1 year postoperatively revealed 7 of 73 studied coronary anastomoses (9.5%) and two distal extensions and resistors were occluded (7%). In 1 patient during sternal debridement at 1 year, no flow was found in the graft.
Conclusions.The Perma-Flow graft is a useful adjunct to complete revascularization in patients with deficient autologous conduit.
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Introduction
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See also page 695.
Coronary artery bypass grafting (CABG) has become one of the most commonly performed operative procedures in the United States. Data have indicated an improved longevity in certain subgroups and an improved quality of life in most patients having this procedure [1–7]. Yet there are some individuals who have inadequate or diseased native conduit that cannot be used for bypass grafting and are denied the advantages of this operation. In some circumstances patients may have contraindications to a peripheral operation due to arterial insufficiency, chronic venous insufficiency, or extremity complications of diabetes mellitus or chronic lymphedema. Additionally, a major cause of morbidity of coronary bypass grafting is he harvest of the greater saphenous vein for use as an autologous conduit [8]. Neither prosthetic nor cryopreserved homologous grafts have provided effective alternatives to date, and heterologous conduits have been ineffective [9]. In spite of sporadic reports of alternative conduit use in bypass grafting, no alternative conduit has achieved prominence [9]. To address these concerns, the Perma-Flow prosthetic coronary graft (PFG) (Possis Medical, Inc, Minneapolis, MN) was developed. This polytetrafluoroethylene conduit is implanted in an arteriovenous configuration. Incorporated into the graft is a Venturi resistor, which controls flow through the conduit, maintaining arterial pressure proximally and venous pressure distally while limiting flow to approximately less than 10% of cardiac output [10]. The coronary anastomoses are sewn side-to-side [11]. This configuration allows constant flow through the graft to prevent stasis and maintain patency, yet allows systemic pressure for perfusion of the coronary arteries (Fig 1
). This report delineates the results of clinical implantation of the PFG in all active investigational centers in North America through December 1995.
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Fig 1. . Hypothetical configuration of the Perma-Flow graft demonstrating the aorto-caval fistula, the distal flow restrictor and two coronary artery anastomoses sewn proximal to the resistor in side-to-side fashion. (Reproduced with permission from reference 11.)
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Material and Methods
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From November 1992 through December 1995, 40 PFGs have been inserted at North American investigational centers (Fig 2) operating under a United States Food and Drug Administration investigational device exemption. Informed consent was obtained from all patients enrolled at the centers. The operative techniques for implantation have been described [11]. Patients were followed up according to a Food and Drug Administration-approved protocol for presence of symptoms and at predefined intervals by echocardiography to determine changes in cardiac function or size, and by cardiac catheterization to determine graft patency. Initially, 6-month and 1-year catheterization was required. However, as experience accrued, the protocol was altered to include a 1-week (same hospital admission) study to define technical errors, and a 1-year study [12]. Follow-up was obtained from data coordinators at each of the centers involved in the study. All patients were managed with aspirin beginning 6 hours after the operative procedure, based on chest tube losses. Values are expressed as means ± standard deviation.
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Fig 2. . Active centers participating in study of the Perma-Flow coronary graft and the number of implants at each center.
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Results
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Forty patients without autologous conduit due to vein stripping (n = 18), prior use in surgical procedures (n = 13), or a combination of the two (n = 5), or with inadequate autologous conduit due to severe chronic venous disease or lymphedema (n = 4), underwent coronary artery bypass grafting using the PFG to complete revascularization. There were 22 men and 18 women, aged 66 ± 9 years (range, 53 to 82 years). Twenty-five of the procedures were primary operations, and 15 were reoperations (38%), of which 5 were second reoperations. Presenting symptoms included unstable angina pectoris (n = 14), stable angina pectoris (n = 22), congestive heart failure (n = 1), and chest pain associated with aortic or mitral valve disease (n = 3). In addition to coronary bypass grafting, 5 patients had associated procedures. Other available autologous conduits were used in addition to the PFG in 32 patients (80%):
The aortic cross-clamp time was 75 ± 36 minutes (range, 28 to 183 minutes).
There were 7 hospital deaths, 2 operative and 5 perioperative, the causes of which are shown in Table 1. One patient had graft occlusion of one of two anastomoses and the distal extension of the PFG contributing to perioperative myocardial infarction, low output syndrome, and subsequent death. The other deaths were not thought to be graft-related, as postmortem examination showed patency of the PFG-coronary anastomoses in all cases (see Table 1).
Table 2 delineates the coronary arteries that were sewn to the PFG graft as well as the total number of anastomoses performed in each procedure. As can be seen, one to four side-to-side anastomoses were constructed on the PFG in a variety of configurations. Complete revascularization was obtained in all patients by using the PFG in addition to available autologous conduit.
The postoperative hospital stay was 17 ± 20 days with a range of 5 to 109 days. Significant postoperative complications occurred in 14 patients:
There was no predominance of any single complication or organ system involvement. Patient follow-up is complete and ranges from 1 to 37 months, with a mean interval of 13 ± 9 months and a total of 415 patient-months.
There were two late deaths at 4 and 6 months postoperatively; both deaths were sudden (see Table 2
). One postmortem examination was obtained, and the PFG anastomoses were patent whereas a saphenous vein graft was closed. Of the surviving 31 patients, 29 are asymptomatic. In one patient two of four PFG anastomoses were closed at 1-week catheterization. Angina developed in this patient 8 weeks postoperatively; he is managed medically. The first patient in whom the PFG was implanted had development of angina at 30 months. Angiography revealed the left internal mammary artery-to-left anterior descending artery anastomosis to be patent as well as both coronary-PFG anastomoses [13]; however, new disease had developed in the circumflex system. This patient is also managed medically.
Thirty-two cardiac catheterizations were carried out in 28 patients; the intervals and results of these studies are shown in Table 3. Note that only 7 of the 73 coronary side-to-side anastomoses studied (9.5%) were not patent. Additionally, two venous portions of the conduit were closed, yet in both, one of two coronary and three of three coronary side-to-side anastomoses remained patent. Only 13 anastomoses were available for evaluation at 1 year; ten of these 13 anastomoses remained patent.
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Comment
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Initially, the PFG was used in patients who had no alternative conduit [13], but because of early encouraging results, the graft was used in later patients who had contraindications to a peripheral operation due to chronic venous stasis disease with brawny edema and stasis ulcers coupled with arterial insufficiency or chronic peripheral lymphedema. The patients in this series in whom the PFG was applied were at high operative risk in terms of percentage of patients with unstable angina pectoris, female patients, and reoperations, consistent with risk factors previously reported and as reflected in the operative mortality (18%) and morbidity [14–17]. Other intangible variables, such as extended medical therapy for surgical disease because of inadequate conduit, also played a role. As well, the pattern of patients having coronary operations in the current decade has become one of higher risk, and the need for alternative conduit to complete revascularization may increase [18–20].
Phase I protocol restricted the use of the PFG to vessels other than the critical vessel. Thus, this graft was not used as the primary agent of revascularization, but as a tool to complete the surgical procedure or revascularization. The operative techniques are well established to allow implantation of the prosthesis without prolongation of the operative procedure, myocardial ischemia, or perfusion time [11]. Follow-up to 37 months has not shown any untoward effects from the presence of a chronic limited arteriovenous fistula or the presence of polytetrafluoroethylene in the pericardial sac. The incidence of late closure (>1 year) may be elevated (23%), in that patients having sequential studies (1 week and 1 year) were operated on in the early portion of the learning curve (n = 3), and the other patients (n = 3) have only a 1-year study, and the anastomoses may have been closed early. Importantly, there are a limited number of anastomoses available for study at 1 year (n = 13).
One venous occlusion occurred in the second patient operated on. The venous extension from the resistor (see Fig 1) to the superior vena caval anastomosis was made longer than currently recommended [11], and this excess length may have allowed for stasis in the venous segment that contributed to thrombosis. This event resulted in the recommendation of the shortened length of the distal venous segment and the change in angiographic follow-up protocol, as early occlusion could then be assigned to poor run-off or faulty surgical technique as previously defined [21].
The results of these early catheterization studies may be usefully compared with those reported in the Veterans Administration 207 Cooperative Study, as the study protocols are similar in terms of follow-up cardiac catheterization [12]. The early occlusion rate of saphenous vein grafts reported in this study was 10% in aspirin-treated groups and 15% in the placebo cohort, as compared with 8% in the current study (see Table 3). Later, Sanz and associates [22], in another multicenter, prospective, randomized, double-blind study, found early occlusion rates of saphenous vein grafts of 13% in an aspirin-treated group and 18% in a placebo group in 927 patients having catheterization a mean of 10 days after revascularization; again, this is a higher occlusion rate than that found in patients revascularized with the PFG. The PFG patency results are similar to those reported in venous grafts by Chesebro and colleagues [23] in aspirin-treated patients who had angiography less than 1 month postoperatively. Previously reported studies in sequential saphenous grafts as a subset of the Veterans Administration 207 study found similar patency rates to that obtained with the PFG [24]. The numbers of patients having sequential studies (1 month and 1 year) are too small as yet (n = 3) for effective comparison with a later follow-up report from this Veterans' Administration cooperative study, demonstrating saphenous graft occlusion in placebo and aspirin-containing cohorts of 23% and 16%, respectively, at 1 year [25]. Additionally, this later report from the Veterans' Administration study confirmed the findings of prior studies and demonstrated that occlusion was greater in vessels smaller than 2 mm, the group to which the PFG was most commonly applied as a completion of revascularization. These sequential Veterans' Administration 207 catheterization studies allow a basis for late follow-up comparison as the protocols for restudy and management are similar, and the variable becomes the graft type, ie, PFG versus saphenous vein [23, 25, 26].
Based on these early data, the PFG is a useful alternative to complete revascularization in patients requiring coronary artery bypass grafting who have inadequate native conduit. Continued study is warranted.
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Acknowledgments
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We thank and acknowledge the efforts of the clinical coordinators for this project at each participating center: Felix Ordoyne, RNFA (West Jefferson Medical Center, New Orleans, LA), Denise O'Donnell, MSN (Norfolk General Hospital, Norfolk, VA), Cathy Custer, RN (The Johns Hopkins Medical Center, Baltimore, MD), Sharon Snyder, RN (The University of Arizona, Tucson, AZ), and Sonja Hoollenbach, BSN (The University of Arizona, Tucson, AZ), as well as other participating physicians: R. Michael King, MD (Minneapolis Heart Institute, Minneapolis, MN), William A. Baumgartner, MD (The Johns Hopkins Medical Center, Baltimore, MD), and Gulshan Sethi, MD (The University of Arizona, Tucson, AZ).
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Footnotes
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Presented at the thirty-second Annual Meeting of The Society of Thoracic Surgeons, Orlando, Fl, January 29-31, 1996.
Address reprint requests to Dr Emery, Cardiac Surgical Associates, PA, 920 E 28th St, Suite 420, Minneapolis, MN 55407.
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References
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- Rogers WJ, Coggin J, Gersh BJ, et al. Ten-year follow-up of quality of life in patients randomized to receive medical therapy or coronary artery bypass graft surgery: the Coronary Artery Surgery Study (CASS). Circulation 1990;82:1647–58.[Abstract/Free Full Text]
- Chaitman BR, Ryan TJ, Krenmal RA, et al. Coronary Artery Surgery Study (CASS): comparability of 10-year survival in randomized and randomizable patients. J Am Coll Cardiol 1990;16:1071–8.[Abstract]
- Sharma CVRK, Deupree RH, Khum SF, Parisi AF, Luchi RJ, Scott SM VA. Unstable Angina Cooperative Study Group. Circulation 1991;84(Suppl 3):260–7.
- Booth DC, Deupree RH, Hultgren NA, et al. Quality of life after bypass surgery for unstable angina: 5-year follow-up results of a Veterans Affairs cooperative study. Circulation 1991;83:87–95.[Abstract/Free Full Text]
- Elefteriades JA, Tolis G Jr, Levi E, Miller LK, Zaret BL. Coronary artery bypass grafting in severe left ventricular dysfunction: excellent survival with improved ejection and functional state. J Am Coll Cardiol 1993;22:1411–7.[Abstract]
- Caracciolo EA, Davis KB, Sopko G, et al. Comparison of surgical and medical group survival in patients with left main coronary disease. Circulation 1995;91:2325–34.[Abstract/Free Full Text]
- Caracciolo EA, Davis KB, Sopko G, et al. Comparison of surgical and medical group survival in patients with left main equivalent coronary artery disease: long term CASS experience. Circulation 1995;91:2335–44.[Abstract/Free Full Text]
- Prevel CD, Ott RA, Davenport-Toczko M, Emery RW. An improved method of closure for saphenous vein donor sites. Ann Thorac Surg 1987;44:425–6.[Abstract]
- Jones E. Conduits for coronary artery bypass. Ann Thorac Surg 1993;55:194–5.[Medline]
- Drassler WJ, Jenson ML, George SA, et al. A unique vascular graft concept for coronary and peripheral applications. ASAIO Trans 1988;34:769–72.[Medline]
- Emery RW, Joyce LD, Arom KV, King RM, Nicoloff DM. Operative considerations in implantation of the Perma-Flow graft. Ann Thorac Surg 1994;58:1770–3.[Abstract]
- Goldman S, Copeland J, Moritz T, et al. Improvement in early saphenous vein graft patency after coronary artery bypass surgery with antiplatelet therapy: results of a Veterans Administration cooperative study. Circulation 1988;77:1324–32.[Abstract/Free Full Text]
- Emery RW, Petersen RJ, Baumgard C, Nicoloff DM. First clinical use of the Possis synthetic coronary graft. J Cardiac Surg 1993;8:439–42.[Medline]
- Loop FD, Golding LR, MacMillan JP, Cosgrove DM, Lytle BW, Sheldon WL. Coronary artery surgery in women compared with men: analyses of risks and long-term results. J Am Coll Cardiol 1983;1:383–90.[Abstract]
- O'Connor GT, Morton JR, Diehl MJ, Olmstead EM, Coffin CH, Levy DG. Differences between men and women in hospital mortality associated with coronary artery bypass graft surgery. Circulation 1993;88(Part 1):2104–10.[Abstract/Free Full Text]
- Louagie YA, Jamart J, Buche M, et al. Operation for unstable angina pectoris: factors influencing adverse in-hospital outcome. Ann Thorac Surg 1995;59:1141–9.[Abstract/Free Full Text]
- Craver JM, Justice A, Shen Y, Weintraub WS, Jones EL, Guyton RA. In-hospital and long outcome after a third coronary bypass procedure [Abstract]. J Am Coll Cardiol 1995;25:183A.
- Naunheim KS, Fiore AC, Wadley J, et al. The changing mortality of myocardial revascularization: coronary artery bypass and angioplasty. Ann Thorac Surg 1988;46:666–74.[Abstract]
- Weintraub WS, Wenger NK, Jones EL, Craver JM, Guyton RA. Changing clinical characteristics of coronary surgery patients: differences between men and women. Circulation 1993;88(Part 2):79–86.
- Disch DL, O'Connor GT, Birkmeyer JD, et al. Changes in patients undergoing coronary artery bypass grafting: 1987–1990. Ann Thorac Surg 1994;57:416–23.[Abstract]
- Campeau L, Enjalbert M, Lesperance J, Vaislic C, Grondin CM, Bourassa MG. Atherosclerosis and late closing of aortocoronary saphenous vein grafts: sequential angiographic studies at two weeks, one year, 5–7 years and 10–12 years after surgery. Circulation 1983;68(Suppl 2):1–7.
- Sanz G, Pajaron A, Alegria E, et al. Prevention of early aortocoronary bypass occlusion by low-dose aspirin and dipyridamole. Circulation 1990;82:765–73.[Abstract/Free Full Text]
- Chesebro JH, Foster V, Elveback LR, et al. Effect of dipyridamole and aspirin on late vein graft patency after coronary bypass operations. N Engl J Med 1984;310:209–14.[Abstract]
- Emery RW, Gay RG, Lancaster L, Collins JT. Use of sequential bypass grafting. In: Copeland JG, Goldman S, eds. Coronary surgery and cardiac surgery: state of the art reviews: improving results with coronary artery bypass grafting. 1986;1:77–86.
- Goldman S, Copeland JG, Moritz T, et al. Saphenous vein graft patency one year after coronary bypass surgery and effects of antiplatelet therapy: results of a Veterans Administration cooperative study. Circulation 1989;80:1190–7.[Abstract/Free Full Text]
- Goldman S, Copeland JG, Moritz TG, et al. Long-term graft patency (3 years) after coronary artery surgery. Effects of aspirin: results of a VA cooperative study. Circulation 1994;89:1138–43.[Abstract/Free Full Text]
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Top
Abstract
Introduction
