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Ann Thorac Surg 2004;77:93-101
© 2004 The Society of Thoracic Surgeons
a Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia,
b Epworth Hospital, University of Melbourne, Melbourne, Victoria, Australia
* Address reprint requests to Dr Tatoulis, Suite 28, Private Medical Centre, Royal Melbourne Hospital, Parkville, Victoria, 3050 Australia.
e-mail: james.tatoulis{at}mh.org.au
Presented at the Thirty-ninth Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 31–Feb 2, 2003.
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Abstract |
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 Top Abstract IntroductionMaterial and methodsResultsCommentAppendix 1Appendix 2Appendix 3DiscussionReferences |
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METHODS: Consecutive postoperative angiograms of 2,127 arterial/coronary conduits were evaluated. Angiograms were performed for cardiac symptoms. Assessment was by two observers. String signs were considered as occlusions.
RESULTS: There were 2,127 arterial conduits. Overall patencies were as follows: LITA, 96.4% (1,296 of 1,345); RITA, 88.3% (534 of 605); aortocoronary RA, 89.3% (158 of 177). The LITA patency to the left anterior descending artery was 97.1% (1,131 of 1,165); to the obtuse marginal artery it was 91.7% (165 of 180; p 0.01). The RITA pedicled graft patency was 86% (275 of 321) compared with free RITA, 91% (259 of 284; p = not significant). For RITA there was a hierarchy of patency for coronary territory grafted (left anterior descending artery best, right coronary/posterior descending artery worst) and for degree of coronary stenosis: if stenosis was less than 60%, patency was 65% (47 of 72); if stenosis was more than 60%, patency was 90.9% (485 of 533; p = 0.0001). Similarly for the radial artery there was higher patency with greater coronary stenosis. The LITA patency at 5 years was 98%, at 10 years it was 95%, and at 15 years it was 88%. The RITA patency at 5 years was 96%, at 10 years it was 81%, and at 15 years it was 65%. The radial artery patency at 1 year was 96% and at 4 years it was 89%. For 3,714 vein grafts also studied overall patency was 61% (2,266 of 3,214) with patencies of 95% at 5 years, 71% at 10 years, and 32% at 15 years.
CONCLUSIONS: Excellent long-term patencies of arterial grafts are noted, superior to those of vein grafts. Patencies were influenced by conduit, by distribution, and by coronary artery stenosis.
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Introduction |
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TopAbstractIntroductionMaterial and methodsResultsCommentAppendix 1Appendix 2Appendix 3DiscussionReferences |
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We have progressively increased the use of arterial grafts initially in 1985 with the left internal thoracic artery (LITA) followed in 1986 by bilateral internal thoracic arteries and then in 1996 by the routine use of the radial artery (RA) in addition to the internal thoracic arteries [9].
Our objective was to achieve total arterial coronary revascularization if possible—as the clinical results were as good or better than where extensive saphenous vein grafting was used—with the additional expectation of superior long-term clinical and patency results, which would include reduced need for coronary reoperation. In our practice total arterial coronary revascularization is possible in more than 90% of all CABG with excellent results [9].
Although there is much documentation of clinical results in CABG there is relatively little information on long-term arterial/coronary conduit patencies. The purpose of this study was to examine the long-term patencies of a large number of arterial grafts in an experience that spans 15 years and to document the anatomic and physiologic behavior of the common arterial conduits. Additionally we wished to evaluate any specific anatomic (conduit or target vessel) factors that influenced long-term arterial graft patency and to document the modes of failure of arterial grafts in the coronary circulation.
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Material and methods |
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TopAbstractIntroductionMaterial and methodsResultsCommentAppendix 1Appendix 2Appendix 3DiscussionReferences |
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All arterial/coronary conduit angiograms in this cohort were performed for postoperative cardiac symptoms. In this study only patients who had coronary graft angiograms for possible cardiac symptoms were considered. These symptoms included recurrent typical angina, atypical chest pain, new or persistent shortness of breath, or presentation with a new myocardial infarction. Asymptomatic patients did not have coronary angiograms. There was no routine postoperative coronary angiography policy with respect to these patients.
During this period there were 10,407 CABG operations in which one or more arterial grafts were used. The rate of total arterial coronary revascularization has risen from 30% in 1995 to 90% since 2000.
Arterial graft procurement and antispasm prophylaxis
The LITA was initially harvested as a narrow pedicle with low-power cautery. Intercostal branches were divided by scissors between titanium clips. Since 1990 the LITA has been harvested with only the medial vein in a "skeletonized" or "semiskeletonized" manner. Inferiorly the dissection always extended to the internal mammary artery bifurcation and proximally as far as possible, dividing all branches. The RITA was harvested in an identical fashion. For both internal mammary arteries, 2 mL of intraluminal papaverine solution (1 mg/mL in heparinized ringers lactate, pH 7.2 at 37°C) has been used. The end is clipped and the internal mammary artery pedicle enveloped in a papaverine solution soaked gauze and left pulsating in situ until use.
Radial artery procurement followed the same principles. The radial artery was harvested together with its venae commitantes and stored in a papaverine solution—papaverine 1 mg/mL in heparinized arterial blood at room temperature—until use. Radial arteries with significant calcification were not harvested. Operative details have been previously published [9–11].
All patients received intravenous nitroglycerine (30 µg to 100 µg/min intraoperatively and for the first 24 hours) and all received enteric-coated aspirin 100 mg daily commencing on the first postoperative day and continuing indefinitely. The calcium-channel blocker amlodipine (5 mg orally daily for 6 months) was used routinely when an radial artery was used [9–11].
Graft strategy: deployment of arterial/coronary conduits
The LITA was used as a pedicled graft almost exclusively to the left anterior descending artery (LAD) system—13% of pedicled LITA grafts were placed to the circumflex marginal artery (CxOM) system. The RITA was used as a pedicled graft if possible. However it was readily used as or converted to a free graft to reach a more favorable site for anastomosis and to avoid stretching. The RITA was more commonly grafted to the right coronary artery/posterior descending artery, followed by the CxOM, and least to the LAD. The RITA when used as a free graft was almost always from the aorta (seldom from the LITA and never from an SVG). A 3.5-mm opening was created in the ascending aorta with a pumch and the anastomosis constructed with continuous 6-0 polypropylene. The proximal end of the free RITA is usually 3 mm internal diameter and has a robust wall. A vein patch on the aorta to facilitate proximal RITA anastomosis has only been used on one occasion.
The radial artery grafts were usually deployed to the circumflex or posterior descending artery and left ventricular branches of the RCA. The LITA-Y-radial artery composite grafts were infrequently performed and not included in this study. The radial artery angiograms in this study were aortocoronary only. Sequential grafting with arterial conduits was rarely used through this experience, extremely rarely before 1997 and seldom from 1997 to 2001 (occasionally with radial arteries). Postoperative angiograms with sequential grafts were excluded from the study.
Supplementary SVG were used as required to achieve complete myocardial revascularization (mean of 3.1 distal anastomoses per patient). Since 1999, fewer than 10% of patients have received an SVG. The right gastroepiploic artery, inferior epigastric artery, and ulnar artery were infrequently used.
In this cohort all CABG were performed using cardiopulmonary bypass, aortic clamping, and cardioplegic arrest. Since 1990 a single cross clamp and combined antegrade and retrograde blood cardioplegia has been used [9–11].
Postoperative angiography
Angiograms were performed under local anesthesia usually by the common femoral artery approach within a cardiac catheterization laboratory. All patients gave informed consent to reangiography and study of their coronary conduits. All angiograms were reported by two observers independently. Conduit/graft failure was defined as total occlusion, a "string" sign (conduit diameter <1 mm), or a stenosis of 80% or greater anywhere within the conduit or at the anastomosis.
An analysis was undertaken to relate arterial/coronary conduit patency to time, conduit type, free or pedicled, coronary territory of conduit deployment, and native coronary artery stenosis. The LITA-radial artery Y-pedicled grafts were excluded from this analysis as they required detailed consideration of the multiple LITA segments, the proximal internal mammary artery/radial artery anastomosis, each subsequent segment of radial artery, and anastomosis. It was thought that this would confound the patency data relating to simple aortocoronary radial artery conduits.
Data collection and analysis
All data (operative and angiographic) were collected prospectively and entered into a computer database program. Intraoperative data were entered at the time of operations. Remote angiographic data were entered at the time of the angiogram report. Values are reported as the mean ± SD. Percentages are given where appropriate. Statistical analysis was with the Statistical Package for Social Sciences (SPSS-PC plus). The 
2 test was used for categorical variables. Conduit survival curves were calculated using the Kaplan-Meier method and compared with the log-rank test. A p value of less than 0.05 was considered significant.
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Results |
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TopAbstractIntroductionMaterial and methodsResultsCommentAppendix 1Appendix 2Appendix 3DiscussionReferences |
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The mean interval from operation to angiography for the 1,345 LITA grafts was 79.3 (± 46.4) months and for the 605 RITA grafts it was 81.9 (± 43.7) months. The majority of the LITA angiograms (887 of 1,345; 66%) were performed 5 or more years postoperatively; for the RITA angiograms also the majority (421 of 605; 69%) were performed 5 or more years postoperatively.
For the LITAs for most 1-year intervals approximately 100 graft studies were performed and this was steady from year 1 postoperative to year 11 postoperative. For the RITA angiograms an average of 50 were performed on a very even basis from year 2 postoperative to year 11 postoperative. The radial artery postoperative angiograms are in a much shorter time frame, with an average of 30 being performed per annum again on a fairly regular basis. The specific details of yearly angiogram numbers for each of the three types of arterial conduits are given in Appendixes 1, 2, and 3.
For all arterial grafts studied (n = 2,127)—irrespective of type—there were 139 graft failures. Overall patency for all arterial conduits was 93.5% (1,988 of 2,127) 76 months postoperatively.
Overall patencies by conduit
The LITA had the best patency, then the RITA, and finally the aortocoronary radial artery. Of the 1,345 LITA conduits studied there were 49 LITA failures. Overall patency was 96.4% (1,296 of 1,345). For the 605 RITA conduits there were 71 RITA failures. Overall RITA patency was 88.3% (534 of 605). For the 177 aortocoronary radial artery conduits there were 19 failures. Overall aortocoronary radial artery patency was 89.3% (158 of 177). These results are summarized in Table 1.
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RITA conduit patencies
Overall patency for pedicled (in situ) RITA grafts was 86% (275 of 321). By comparison, patency for free RITA grafts was 91% (259 of 284; p = 0.564). Coronary artery territory influenced RITA patency. There was a hierarchy of patency, with best patency to the LAD then the CxOM, and lastly the right coronary artery/posterior descending artery territory. For RITA to LAD patency was 95% (131 of 138). For RITA to CxOM patency was 90% (192 of 213). For RITA to the right coronary artery/posterior descending artery patency was 83% (211 of 254; p < 0.01 between each group).
Aortocoronary radial artery conduit patencies
Patencies to the different territories were similar. Coronary territory did not appear to influence patency of the aortocoronary radial artery. Radial artery patency to the LAD was 87% (27 of 31), to the circumflex marginal it was 92% (87 of 95), and to the right coronary artery/posterior descending artery territory it was 88% (45 of 51; p = 0.392). Patencies of arterial conduits by territory are detailed in Table 2.
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Pedicled internal thoracic artery grafts to the LAD
Patencies for both pedicled (in situ) right internal thoracic artery and left internal thoracic artery grafts to the LAD were excellent. For the pedicled LITA to LAD, patency was 97% (11,31 of 1,345) and for the pedicled RITA to LAD, patency was 95% (131 of 138; p = 0.821).
Cumulating all the conduits, the probability of having a patent conduit according to the territories are as follows: for the left anterior descending 97% (1,289 of 1,334); for the circumflex 91% (444 of 488); and for the right coronary artery/posterior descending artery 84% (256 of 305) at a mean of 76 months postoperative.
Native coronary artery stenosis: influence on patency
There was a significant influence by the degree of native coronary artery stenosis on arterial conduit patency. The more severe the native coronary artery stenosis, the higher the patency. The threshold stenosis for this effect was a stenosis of 60% for LITA and RITA. Radial artery conduits were more sensitive; the threshold stenosis was 80%.
Although pedicled LITA graft patencies followed the same patterns, the effects on LITA patency were less severe. The results are summarized in Table 3. The poorest patency was for the RITA to coronary arteries with a stenosis of less than 60% (usually pedicled RITA to large right coronary arteries; Fig 1).
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Arterial conduit failures: qualitative observations
When arterial grafts failed, there were three modes: total occlusion; a string sign—where the length of the graft could be seen from its origin—to the target coronary artery, however the graft diameter was less than 1 mm and deemed nonfunctional; or a discrete
stenosis (Figs 3 and 4).There
were no intraluminal irregularities suggesting atheroma or thrombus—in contrast to the changes seen in patent diseased SVG. Patent arterial grafts were uniform and had larger diameters than the target coronary arteries (Fig 5).
The incidence of arterial/coronary conduit spasm was exceedingly low. When spasm occurred it was usually in radial artery (4 cases) weeks to months postoperatively, localized more than 1 cm, and resolved angiographically with intraluminal nitroglycerin.
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Comment |
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TopAbstractIntroductionMaterial and methodsResultsCommentAppendix 1Appendix 2Appendix 3DiscussionReferences |
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By comparison arterial grafts—particularly the LITA and also the RITA—have been associated with better patencies and improved clinical results including fewer cardiac events and a greater life expectancy [4–8]. The results with respect to the radial artery are promising [10–15] and comparable with or better than when SVGs are used, particularly as a second conduit of choice after the internal mammary artery. Since 1985 we have incrementally used more arterial grafts to achieve better long-term clinical outcomes. That has resulted in a large experience with arterial grafts and with total arterial coronary revascularization [9].
This study of 2,127 arterial/coronary conduits at a mean interval of almost 80 months represents one of the largest late angiographic studies of arterial/coronary conduits. The large numbers allow greater confidence in interpretation of patterns of conduit patency or failure. The angiograms were performed in a symptomatic group of patients and hence the observed results may be biased toward poorer patencies. Despite this the patencies for arterial grafts are excellent and at 10 and 15 years are clearly superior to SVG.
For the LITA this study confirms the excellent patencies noted by Loop and associates [4] and others [16–18]. Nevertheless the pedicled LITA displayed a slightly lower patency when grafted to the CxOM. This may be due to greater technical difficulty, "stretching" of the LITA pedicle to reach an inferior marginal, and smaller less optimal target vessels with a more limited runoff than the LAD.
Coronary territory also influenced RITA patency. A hierarchy of patency was observed—best to the LAD then the CxOM and finally the right coronary artery/posterior descending artery. Hence there may be benefits of RITA grafting to the left sided coronary arteries [19]. Patency of the RITA to the LAD was identical to that of the LITA to the LAD—indicating that equivalent biological conduits to the same vascular bed produce identical results. The superior patency of the RITA when placed to the LAD by comparison to the other territories may be explained by shorter graft length, technical ease, and better runoff.
In this large series of RITA angiograms there were similar numbers of pedicled and free RITAs. Overall patencies of these groups were similar. Within each of the pedicled and the free RITA groups, again a hierarchy of patency was observed, the poorest patency being to the right coronary artery/posterior descending artery, indicating that the coronary territory and its vascular bed is a significant determinant of long-term patency.
With respect to the right coronary artery/posterior descending artery system a pedicled RITA may provide limitation as to how distal it will reach—sometimes resulting in construction of the anastomosis in a suboptimal area of wall thickening. Additionally the RCA is notorious for the development and progression of further disease distal to an anastomosis (usually near the crux). Under these circumstances if the RITA is to be used the patient may be best served by a free RITA graft to the PDA beyond proximal wall disease.
The routine procurement of the internal mammary arteries as skeletonized grafts ensures a further 2 to 3 cm in length, enabling more distal anastomosis if desirable. Although initially there was concern that internal mammary artery skeletonization may lead to trauma or disruption of the vascular supply of the internal mammary artery wall, the clinical and early angiographic results in skeletonized internal mammary artery are excellent [20].
Use of the radial artery as the second conduit of choice after the internal mammary artery is relatively recent and increasingly popular. In this study radial artery patency although inferior to that of internal mammary arteries was excellent. Again there was a tendency for lower patency when the radial artery was anastomosed to the right coronary artery/posterior descending artery. Patency information for the radial artery is still being gathered but this experience concurs with other reports [11, 12, 14, 15, 21, 22]. To date the radial artery patencies are excellent at 96% at 1 year and 90% at 27 months. Another 5 years of data are required before meaningful comparisons to the internal mammary artery can be made.
Native coronary artery stenosis had a major influence on arterial conduit patency. This study reconfirms earlier observations that for arterial grafts the best patency is achieved when placed to tightly stenosed or occluded coronary vessels [12, 14, 21, 22]. All three conduits (LITA, RITA, and radial artery) whether pedicled or free behaved similarly. The pedicled LITA was the most versatile and least sensitive. By contrast the radial artery was the most sensitive, patency being significantly affected if native coronary artery stenosis was less than 80% (by comparison with the internal mammary arteries, native coronary artery stenosis < 60%). The greater sensitivity of the radial artery may be due to its thicker muscular wall [23]. Native coronary artery stenosis influences right gastroepiploic artery patency in a similar manner [24, 25]. The lowest patencies were achieved when the RITA (attached or free) or the radial artery were anastomosed to the right coronary artery with less than 60% stenosis—implicating a number of etiologic factors such as wall disease, progression of distal lesions, competitive flow, and "vascular remodeling" [23].
Also the concept of a 60% stenosis is relative. A 60% stenosis in a 5-mm right coronary artery will result in different (greater) native coronary flow and competitive flow by comparison to a 60% stenosis in a 2-mm LAD or CxOM. The large dominant right coronary artery with a moderate (50% to 60%) stenosis presents a dilemma. Some authors argue that an excellent SVG may be a more appropriate conduit in that setting [25]. Rapamycin drug-eluting stents may also have a role.
Patencies noted in this study are similar to, confirm, and add to the results published for LITA [4, 16–18, 20], for RITA [15, 16, 19], and for radial artery [11, 12–15, 21, 22].
With arterial coronary conduits it is hoped that once technical and competitive flow factors are overcome that constant patency would be maintained over the long term. However there is still some late graft failure. Possible explanations include a conduit that may have occluded at year 2 may not be discovered until year 10, when for some additional reason the patient becomes symptomatic and an angiogram is performed. The progress of coronary lesions distal to the anastomosis, resulting in poor runoff and graft failure (Fig 6). We have observed patent grafts to subsequently occlude on serial angiograms. Additionally intrinsic biologic factors affecting myocytes, fibroblasts, and endothelial cells in the arterial conduit wall may result in long-term changes [23]. Some patients can display an intense inflammatory reaction around the conduit (seen at reoperation), which may result in longer term perigraft fibrosis and conduit failure.
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Unlike SVG occlusive atherothrombotic changes are not seen angiographically (nor clinically at redo operations) in arterial conduits. Implications are that arterial conduits are not susceptible to abrupt closure (in contrast to a severely diseased and stenosed SVG) and in a reoperation, an arterial graft would not be a hazardous source of accidental atheroembolism—making coronary reoperations (if such had to be undertaken) safer. Ten years postoperatively we should expect arterial/conduit patencies of between 80% (radial artery, RITA) and 95% (LITA) and at 15 years, patencies of 65% to 90%, which are clearly superior to those of SVG. The concept of improved long-term clinical outcomes and prognosis when increased numbers of arterial grafts are used is supported by many authors [4–9].
Based on the present data optimal patencies (and clinical results) are achieved by deployment of the LITA to the LAD, the RITA (pedicled—if it will comfortably reach—or free) to the CxOM and the radial artery to the posterior descending artery.
Limitations of the study
Limitations include that it is an observational study of symptomatic patients and possibly biased toward lower patencies. The exact time of the conduit occlusions is not known. It is assumed that they occurred at the time of angiography. However all occlusions must have occurred a variable period of time before angiography. The angiographic cohort represents less than 15% of all patients undergoing CABG with arterial grafts during this time frame. Reporting of minor abnormalities in grafts or at anastomotic points is problematic. Unless the changes were severe (stenosis 
80%), conduits were reported as normal. The radial artery follow-up is short and LITA/radial artery Y grafts have been excluded. Prior reports of LITA/radial artery Y grafts have documented excellent LITA to LAD and radial artery to OM patencies but poor patencies of the distal limb of the radial artery Y graft to the posterior descending artery. Patency in the Y radial artery limb is also significantly influenced by native coronary stenosis and competitive flow [21, 22].
In conclusion in this study of a large number of late postoperative arterial/coronary conduit angiograms excellent long-term patencies of arterial conduits are documented and are superior to those of saphenous vein grafts. Patencies were influenced by conduit type, coronary artery territory to which they were applied, and by the degree of target native coronary artery stenosis.
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Appendix 1 |
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TopAbstractIntroductionMaterial and methodsResultsCommentAppendix 1Appendix 2Appendix 3DiscussionReferences |
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Appendix 3 |
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TopAbstractIntroductionMaterial and methodsResultsCommentAppendix 1Appendix 2Appendix 3DiscussionReferences |
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Discussion |
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TopAbstractIntroductionMaterial and methodsResultsCommentAppendix 1Appendix 2Appendix 3DiscussionReferences |
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The 5-year patency of 95% for the vein graft is amazing but the high late closure rate is universal owing to progressive atherosclerosis of the graft. The relatively high closure rate of 21% for the radial artery graft at 5 years, although excellent at 1 year, is somewhat disappointing. This rate is probably due to the high incidence of string phenomenon of the radial artery graft when anastomosed to the artery with physiologically insignificant stenosis. The radial artery grafts tends to undergo thinning more frequently than the ITA and the vein graft. The authors considered thinned graft or string graft as occluded but that is a very controversial point.
Arterial grafts with functioning endothelium undergo arterial remodeling to maintain shear stress to the endothelial wall, which enhances the production of nitric oxide when flow through it decreases. Suppose the radial artery and ITA endothelial cells function equally to the same level of shear stress against arterial remodeling, flow of the radial artery graft must be eight times larger than that of the ITA graft after bypass operation.
In other words, after CABG when graft flow is the same through the radial artery graft and ITA graft, remodeling or string is several times more common for the radial artery graft than for the ITA graft. So I would say that radial artery graft may be the suitable graft material for sequential grafting to increase the flow through it. Vein graft does not respond well to the shear stress change. The diameter of arterial conduits reduces to the various degree from thinning or a string sign, to oscillating flow phenomenon, no-flow patency, and eventual thrombosis. The clear-cut separation of various levels of arterial remodel is difficult.
This slide shows our data published in 1992 (J Thorac Cardiovasc Surg 1992;104:1532–8). When the degree of coronary stenosis is less than 60% to 70%, the ITA graft size begins to reduce from the original diameter 1.5 mm but this remodeling process can reverse when flow requirement increases if not thrombosed.
This slide shows the angiographic demonstration of no-flow anatomical patency on the ITA graft. In the left panel you see the ITA graft looks closed according to Dr Tatoulis' criteria but when the recipient LAD was temporarily occluded with a PCI balloon, then the ITA showed apparent flow to the LAD as shown in the middle panel. No flow or thinned grafts have a potential to redilate and grow in size later depending upon the flow requirement as shown in the right panel. Angiographic judgment of patency is somewhat equivocal with regard to arterial grafts, and thus angiographic indications for and the planning and execution of a reoperation are also equivocal. The endothelium-dependent arterial remodeling process is propitious in the circumstance of increased conduit flow but unfavorable in the circumstance of reduced flow. We may need specific medications to counteract the remodeling process of the radial artery graft and other arterial grafts as well.
My question for Dr Tatoulis is threefold. First, you mentioned that the thinned artery graft was judged as closed. Then what was the rate of string phenomenon contributing to your closure rate of each arterial graft? If you consider that the string effect of the arterial graft is undesirable and should be counted as graft closure, who or what would be responsible for this undesirable result, cardiologists or surgeons who made an indication or recipient artery or graft itself? How often do you replace the thinned artery graft as a cause of unfavorable results?
Second, can surgeons overcome this shortcoming of a live arterial conduit? When we place the graft to the coronary artery with 50% stenosis, probably we better put this anastomosis side to side in sequential fashion, ending with a more stenotic artery, or use a radial artery as a stem graft before bifurcated to multiple target anastomoses. Do you agree with this strategy? How do you speculate on the late fate of the radial artery graft over 10 years?
Last, about antispasm or anticoagulation therapy for arterial conduits: what kind of and how long do you give the patient those medications, particularly for the patient with a radial artery graft?
DR TATOULIS: Thank you, Dr Kitamura, for that discussion and the questions. Briefly to answer the complex issues, regarding string signs, we are still exploring what this means. I think it probably means a spectrum of things. In the pedicled grafts like the left internal thoracic artery graft, a string sign may not represent failure; it may represent remodeling. And with occlusion of the native LAD, perhaps the left internal thoracic artery can open up again as has been demonstrated in the literature. However for free grafts like radial artery grafts and free right internal thoracic artery grafts, I believe that if the string sign has been present for more than a few weeks or months it would be permanent. We have reoperated on patients who have shown string signs and the grafts look quite small. We have actually taken some sections of them to display those changes.
Who is responsible? I don't know. Probably the surgeon, because it's a dilemma, particularly with a big right coronary artery. If you have a 5-mm coronary artery and a 50% to 60% stenosis in a young patient, what do you do? I think that dilemma will stay with us for a long time. The ultimate problem is competitive flow and I think we still are grappling with how to best address that issue in the different age groups. With the right coronary artery, a number of surgeons are saying that perhaps that is not such an important territory; and whether you put a mammary, a radial, a gastroepiploic or vein graft to that site, it probably doesn't matter. I am not sure if that's correct but we will see.
How do we overcome the shortcomings? We do use sequential grafting if we can, if the anatomy is appropriate, but again most of these grafts in the angiographic study as I indicated were straight aortocoronary radials and most of those did not have sequential grafting.
Antispasmodics? We use nitroglycerin perioperatively for 24 hours intravenously and then amlodipine (which is a once-a-day calcium-channel blocker) for 6 months, based on some empirical observational data that we have had over time. Anticoagulants? We use aspirin 100 mg daily indefinitely. I thank the Society for the opportunity of presenting this paper.
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N. J.G.M. Veeger, G. F. Panday, A. A. Voors, J. G. Grandjean, J. van der Meer, and P. W. Boonstra Excellent Long-Term Clinical Outcome After Coronary Artery Bypass Surgery Using Three Pedicled Arterial Grafts in Patients With Three-Vessel Disease Ann. Thorac. Surg., February 1, 2008; 85(2): 508 - 512. [Abstract] [Full Text] [PDF]
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K.-B. Kim, K. R. Cho, and D. S. Jeong Midterm angiographic follow-up after off-pump coronary artery bypass: serial comparison using early, 1-year, and 5-year postoperative angiograms. J. Thorac. Cardiovasc. Surg., February 1, 2008; 135(2): 300 - 307. [Abstract] [Full Text] [PDF]
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 E. Gongora and T. M. Sundt III Myocardial Revascularization with Cardiopulmonary Bypass Card. Surg. Adult, January 1, 2008; 3(2008): 599 - 632. [Full Text]
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I. A. Tarhan, T. Kehlibar, Y. Arslan, M. Yilmaz, M. Dumantepe, K. Berkoz, C. Pancaroglu, and A. Ozler Effects of normothermic organ bath and verapamil nitroglycerin solution alone or in combination on the blood flow of radial artery Eur. J. Cardiothorac. Surg., October 1, 2007; 32(4): 617 - 622. [Abstract] [Full Text] [PDF]
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 H. Suma, H. Tanabe, A. Takahashi, T. Horii, T. Isomura, H. Hirose, and A. Amano Twenty Years Experience With the Gastroepiploic Artery Graft for CABG Circulation, September 11, 2007; 116(11_suppl): I-188 - I-191. [Abstract] [Full Text] [PDF]
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S. Bleiziffer, I. Hettich, B. Eisenhauer, D. Ruzicka, M. Wottke, J. Hausleiter, S. Martinoff, M. Morgenstern, and R. Lange Patency rates of endoscopically harvested radial arteries one year after coronary artery bypass grafting J. Thorac. Cardiovasc. Surg., September 1, 2007; 134(3): 649 - 656. [Abstract] [Full Text] [PDF]
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D. de Canniere, G. Wimmer-Greinecker, R. Cichon, V. Gulielmos, F. Van Praet, U. Seshadri-Kreaden, and V. Falk Feasibility, safety, and efficacy of totally endoscopic coronary artery bypass grafting: Multicenter European experience J. Thorac. Cardiovasc. Surg., September 1, 2007; 134(3): 710 - 716. [Abstract] [Full Text] [PDF]
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Y. J. Loh, M. Nakao, W. D. Tan, C. H. Lim, Y. S. Tan, and Y. L. Chua Factors Influencing Radial Artery Size Asian Cardiovasc Thorac Ann, August 1, 2007; 15(4): 324 - 326. [Abstract] [Full Text] [PDF]
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C. J. Botman, J. Schonberger, S. Koolen, O. Penn, H. Botman, N. Dib, E. Eeckhout, and N. Pijls Does Stenosis Severity of Native Vessels Influence Bypass Graft Patency? A Prospective Fractional Flow Reserve-Guided Study Ann. Thorac. Surg., June 1, 2007; 83(6): 2093 - 2097. [Abstract] [Full Text] [PDF]
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A. Azmoun, R. Ramadan, N. Al-Attar, C. Kortas, S. Ghostine, C. Caussin, M.-L. Bourachot, B. Lancelin, M. Slama, and R. Nottin Exclusive Internal Thoracic Artery Grafting in Triple-Vessel-Disease Patients: Angiographic Control Ann. Thorac. Surg., June 1, 2007; 83(6): 2098 - 2102. [Abstract] [Full Text] [PDF]
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T. J. Gardner Searching for the Second-Best Coronary Artery Bypass Graft: Is It the Radial Artery? Circulation, February 13, 2007; 115(6): 678 - 680. [Full Text] [PDF]
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N. D. Desai, C. D. Naylor, A. Kiss, E. A. Cohen, R. Feder-Elituv, S. Miwa, S. Radhakrishnan, J. Dubbin, L. Schwartz, S. E. Fremes, et al. Impact of Patient and Target-Vessel Characteristics on Arterial and Venous Bypass Graft Patency: Insight From a Randomized Trial Circulation, February 13, 2007; 115(6): 684 - 691. [Abstract] [Full Text] [PDF]
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G. D. Webb, L. H. Lim, V. M.S. Oh, R. El Oakley, C. N. Lee, P. S. Wong, W. M. M. Aye, E. S.Y. Chan, and P. K. Moore Expression of neuronal nitric oxide synthase in the internal thoracic artery and saphenous vein. J. Thorac. Cardiovasc. Surg., November 1, 2006; 132(5): 1131 - 1136. [Abstract] [Full Text] [PDF]
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M. R. Katz, F. Van Praet, D. de Canniere, D. Murphy, L. Siwek, U. Seshadri-Kreaden, G. Friedrich, and J. Bonatti Integrated Coronary Revascularization: Percutaneous Coronary Intervention Plus Robotic Totally Endoscopic Coronary Artery Bypass Circulation, July 4, 2006; 114(1_suppl): I-473 - I-476. [Abstract] [Full Text] [PDF]
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D. Di Lazzaro, T. Ragni, G. Di Manici, G. Bardelli, U. Da Col, F. Grasselli, A. Antoniella, W. Papa, F. Crusco, and A. Giovagnoni Noninvasive midterm follow-up of radial artery bypass grafts with 16-slice computed tomography. Ann. Thorac. Surg., July 1, 2006; 82(1): 44 - 50. [Abstract] [Full Text] [PDF]
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K.-B. Kim, K. R. Cho, J.-S. Choi, and H.-J. Lee Right Gastroepiploic Artery for Revascularization of the Right Coronary Territory in Off-Pump Total Arterial Revascularization: Strategies to Improve Patency Ann. Thorac. Surg., June 1, 2006; 81(6): 2135 - 2141. [Abstract] [Full Text] [PDF]
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K. R. Cho, J.-S. Kim, J.-S. Choi, and K.-B. Kim Serial angiographic follow-up of grafts one year and five years after coronary artery bypass surgery. Eur. J. Cardiothorac. Surg., April 1, 2006; 29(4): 511 - 516. [Abstract] [Full Text] [PDF]
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R. J.F. Baskett, F. H. Cafferty, S. J. Powell, R. Kinsman, B. E. Keogh, and S. A.M. Nashef Total Arterial Revascularization is Safe: Multicenter Ten-Year Analysis of 71,470 Coronary Procedures Ann. Thorac. Surg., April 1, 2006; 81(4): 1243 - 1248. [Abstract] [Full Text] [PDF]
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S. G. Raja Drug-Eluting Stents and the Future of Coronary Artery Bypass Surgery: Facts and Fiction Ann. Thorac. Surg., March 1, 2006; 81(3): 1162 - 1171. [Abstract] [Full Text] [PDF]
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 M. W. Khalil, A. Chaterjee, G. MacBryde, P. K. Sarkar, and R. R. D. Marks Single dose parecoxib significantly improves ventilatory function in early extubation coronary artery bypass surgery: a prospective randomized double blind placebo controlled trial Br. J. Anaesth., February 1, 2006; 96(2): 171 - 178. [Abstract] [Full Text] [PDF]
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S. Miwa, N. Desai, T. Koyama, E. Chan, E. A. Cohen, S. E. Fremes, and Radial Artery Patency Study Investigators Radial Artery Angiographic String Sign: Clinical Consequences and the Role of Pharmacologic Therapy Ann. Thorac. Surg., January 1, 2006; 81(1): 112 - 119. [Abstract] [Full Text] [PDF]
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O. Teskin, B. S. Uydes-Dogan, Y. Enc, F. I. Alp, D. Kaleli, S. Keser, T. Iyigun, F. Bilgen, S. Dagsali, and O. Ozdemir Comparative Effects of Tolazoline and Nitroprusside on Human Isolated Radial Artery Ann. Thorac. Surg., January 1, 2006; 81(1): 125 - 131. [Abstract] [Full Text] [PDF]
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 U. Klima, T. Kofidis, A. Boening, and A. Haverich Long term angiographic monitoring reveals safety and efficacy of the Converge end-to-side anastomotic coupler Interactive CardioVascular and Thoracic Surgery, December 1, 2005; 4(6): 505 - 508. [Abstract] [Full Text] [PDF]
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C. M. Jones, T. Athanasiou, P. P. Tekkis, V. Malinovski, S. Purkayastha, A. Haq, J. Kokotsakis, and A. Darzi Does Doppler echography have a diagnostic role in patency assessment of internal thoracic artery grafts? Eur. J. Cardiothorac. Surg., November 1, 2005; 28(5): 692 - 700. [Abstract] [Full Text] [PDF]
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I. Parvaiz, J. T. Lund, and H. Kelbaek The Arterial Sling Operation: One-Year Follow-Up Ann. Thorac. Surg., October 1, 2005; 80(4): 1375 - 1380. [Abstract] [Full Text] [PDF]
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G. P. Georghiou, B. A. Vidne, and J. Dunning Does the radial artery provide better long-term patency than the saphenous vein? Interactive CardioVascular and Thoracic Surgery, August 1, 2005; 4(4): 304 - 310. [Abstract] [Full Text] [PDF]
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S. Karthik, A. K. Srinivasan, A. D. Grayson, T. Friede, and B. M. Fabri Effect of the Left Internal Mammary Artery to the Left Anterior Descending Artery on Mortality and Morbidity After Combined Coronary and Valve Operations Ann. Thorac. Surg., July 1, 2005; 80(1): 163 - 169. [Abstract] [Full Text] [PDF]
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J. V. Manchio, J. Gu, L. Romar, J. Brown, J. Gammie, R. N. Pierson III, B. Griffith, and R. S. Poston Disruption of Graft Endothelium Correlates With Early Failure After Off-Pump Coronary Artery Bypass Surgery Ann. Thorac. Surg., June 1, 2005; 79(6): 1991 - 1998. [Abstract] [Full Text] [PDF]
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O. A. Khan, R. Chau, C. Bertram, M. A. Hanson, and S. K. Ohri Fetal origins of coronary heart disease--implications for cardiothoracic surgery? Eur. J. Cardiothorac. Surg., June 1, 2005; 27(6): 1036 - 1042. [Abstract] [Full Text] [PDF]
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P. P. Lima Canadas, A. C. Canas, J. L. Orradre Romeo, C. I. Rubio Martinez, L. F. Lopez Almodovar, and M. Calleja Hernandez Endothelium histological integrity after skeletonized dissection of the left internal mammary artery with ultrasonic scalpel Interactive CardioVascular and Thoracic Surgery, June 1, 2005; 4(3): 160 - 162. [Abstract] [Full Text] [PDF]
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A. Boening, F. Schoeneich, A. Lichtenberg, E. Bagaev, J. T. Cremer, and U. Klima First clinical results with a 30{degrees} end-to-side coronary anastomosis coupler Eur. J. Cardiothorac. Surg., May 1, 2005; 27(5): 876 - 881. [Abstract] [Full Text] [PDF]
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P.-E. Falcoz, S. Chocron, C. Binquet, L. Stoica, D. Kaili, C. Quantin, and J.-P. Etievent Revascularization of the Right Coronary Artery: Grafting or Percutaneous Coronary Intervention? Ann. Thorac. Surg., April 1, 2005; 79(4): 1232 - 1239. [Abstract] [Full Text] [PDF]
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K. M. Vural, Z. H. Iscan, A. Kunt, E. Sener, and O. Tasdemir Off-Pump, In Situ Internal Thoracic Artery Grafting: A Durable Treatment for Single-Vessel Coronary Artery Disease Ann. Thorac. Surg., March 1, 2005; 79(3): 814 - 818. [Abstract] [Full Text] [PDF]
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M. Tabata, S. Takanashi, T. Fukui, T. Horai, T. Uchimuro, K. Kitabayashi, and Y. Hosoda Off-Pump Coronary Artery Bypass Grafting in Patients With Renal Dysfunction Ann. Thorac. Surg., December 1, 2004; 78(6): 2044 - 2049. [Abstract] [Full Text] [PDF]
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D. Nezic Reply J. Thorac. Cardiovasc. Surg., November 1, 2004; 128(5): 800 - 801. [Full Text] [PDF]
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 M. Sata and R. Nagai Origin of Neointimal Cells in Autologous Vein Graft Arterioscler Thromb Vasc Biol, July 1, 2004; 24(7): 1147 - 1149. [Full Text] [PDF]
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 R. H. Jones The year in cardiovascular surgery J. Am. Coll. Cardiol., May 5, 2004; 43(9): 1706 - 1714. [Full Text] [PDF]
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