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Eur J Cardiothorac Surg 2002;21:1020-1025
© 2002 Elsevier Science NL
a Division of Cardiac Surgery, University of Verona, Medical School, OCM Borgo Trento, Piazzale Stefani 1, 37126, Verona, Italy
b Division of Cardiology, University of Verona, Medical School, OCM Borgo Trento, Piazzale Stefani 1, 37126, Verona, Italy
c Division of Cardiology Legnago Hospital, Verona, Italy
Received 18 September 2001; received in revised form 11 January 2002; accepted 30 January 2002.
* Corresponding author. Tel.: +39-45-807-2476; fax: +30-45-807-3308
e-mail: fsant{at}yahoo.com
| Abstract |
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Key Words: Coronary artery disease Coronary artery surgery Endarterectomy Reconstructive surgery
| 1. Introduction |
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According to different studies, in up to 25% of these cases with a diffuse coronary artery disease (CAD), standard coronary artery bypass technique cannot be safely performed and the condition is often deemed inoperable [1,2]. In an effort to expand surgical indication to this cohort of patients, several techniques have been introduced including endarterectomy [311] and different means of reconstruction of the left anterior descending coronary artery (LAD), often utilized simultaneously [1218].
Aim of this study was to analyze retrospectively our experience with extensive reconstruction of the LAD by an autologous vein patch, with or without associated endarterectomy (EA), completed by left internal mammary artery (LIMA) grafting onto the patch, in this very challenging group of patients.
| 2. Materials and methods |
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Postoperative care of these patients was standard. An aspirin regimen was initiated in all patient within 24 h. In those cases with an associated endarterectomy, Coumadin (warfarin sodium) was administered for the first 3 months (recommended an INR of 22.5) and then discontinued for aspirin.
Patients were followed up directly in our outpatient clinic, mailed questionnaires, or contacted directly by telephone. Data including physical examination, laboratory tests, electrocardiography, exercise stress testing and echocardiography were collected at regular intervals. Evaluation with coronary angiography was proposed by the 6th postoperative month. Follow-up is 99% complete, comprising a mean follow-up time of 47±20 months (range 590 months), totaling 3854 patient-years.
All continuous variables are presented as mean±standard deviation. Basic methods of univariate analysis included the
2 and Student's t-test. Actuarial estimates of morbid events were calculated by the KaplanMeier survival analysis method. Values of P less than 0.05 were considered significant.
| 3. Results |
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There were five late cardiac deaths (6%; recurrent acute myocardial infarction=3; congestive heart failure=1; and embolic=1). Actuarial survival at 3 and 5 years were 93 and 81%, respectively (Fig. 4) .
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Actuarial freedom from recurrent angina at 3 and 5 years were 77 and 69%, respectively (Fig. 4). Follow-up angiograms were collected in 49 patients (60%). During the evaluation of the images special attention was devoted to the patency of septal and diagonal branches, and their effect on septal and lateral wall contractility. Analysis revealed a full patent LAD graft in 40 cases (GI; 82%) (Fig. 5a) , versus poor run-off/occluded graft in the remaining nine cases (GII; 18%) (Fig. 5b). A poor run-off was often associated with a dilated and redundant vein patch. As expected, clinical evaluation revealed that anginal status was significantly worse in GII patients (P<0.05). All symptomatic patients were addressed to medical therapy.
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| 4. Discussion |
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In 1987 Fundarò [12], and afterwards Ladowsky [13], Lemma [14], Aranky [15], and others [16,17], have introduced with some technical modifications the saphenous vein patch reconstruction and internal mammary artery grafting of the LAD, almost always associated with endarterectomy, in an effort to achieve complete revascularization and provide the long-term patency benefits of IMA grafting [18].
Since 1994 we have adopted the procedure but limiting the associated endarterectomy to only those cases with extensively calcified LAD wall. As shown by our population of patients which represents only a small portion (1.4%) of the entire cohort of patients who underwent myocardial revascularization at our Institution in the last 7 years, the conventional candidate for this operation is usually a male in the seventh decade of life, with several risk factors for atherosclerosis, angina in advanced class, diffuse coronary disease often with distal involvement of the LAD, history of myocardial infarction with some degree of left ventricular impairment, and therefore increased predicted surgical risk [20,21]. Conventional techniques such as double or sequential grafting of the LAD, routinely performed in selected cases, appear less feasible in these patients in view of the extension of the disease. Indeed the necessity to perform multiple sequential IMA grafting extended to the distal LAD might preclude the use of an in situ IMA and/or oblige to use the distal portion of the artery more prone to spasm.
The chosen procedure was almost always planned in advance based on cardiac angiograms. As shown by previous study [16] and data coming from our own first postoperative angiograms, great attention was devoted to fashion the vein patch not redundant since its compliance may be responsible for energy loss and poor run-off. Indeed, in three cases in GII, the inadequate flow through the graft was associated with an irregular and patulous vein patch and with evidence of an akinetic septal wall.
In our experience the LIMA was always anastomosed entirely to the vein patch taking advantage of this pliable structure compare to the stiffness of the calcified LAD wall, this being the main advantage compared to the technique suggested by Aranky [15], possibly less time consuming, where the LIMA is anastomosed in between the native LAD and the vein patch.
Several reason prompted us to limit coronary artery endarterectomy to only those vessels with heavily calcified wall. As previously reported, after this procedure, because of lack of endothelium, all the subendothelial material exposed to blood flow can trigger the coagulation cascade. With poor distal run-off clot formation may occur and progress with resultant thrombosis of the lumen [7]. Although none of the patients with associated LAD endarterectomy suffered an anterior myocardial infarction versus three in the subgroup without, we are incline not to interpret this more favourable outcome, still statistically not significant, as related to the associated procedure.
Hospital mortality with patch reconstruction of the LAD artery and LIMA graft was low and rewarding when compared to similar studies [1217]. However, the rate of perioperative myocardial infarction was fourfold that for CABG alone performed at the same institute (8 versus 2.1%), thus confirming the high risk profile of these patients. Interestingly enough, when only areas supplied by the LAD artery were taken into account, the incidence of perioperative (anterior) myocardial infarction falls to 3.6%, which accounts for the efficacy of the procedure.
An 82% patency rate was shown at postoperative angiograms performed random in 60% of the study population. Indeed, almost all survivors showed a progression on the CCS, with 57 patients (74%) asympthomatic at latest follow-up, with echocardiographic evidence of preserved contractility of the anterior segments.
Although our cases were not prospectively matched to a more conventional group of patients with coronary disease requiring CABG, the rate of mulfunctioning LIMA-to-LAD grafts found at post-operative angiograms was indeed quite high (18%). Whether these results might be related to a rapid progression of the disease associated to poor initial run-off or rather to technical aspects (three cases with redundant vein patch), remains unclear. Five late cardiac deaths, in three cases for recurrent myocardial infarction, as well as a recurrent angina in 20 patients (26%), appear to underline the high risk profile of this population recommending a close follow-up on these patients with an aggressive control of risk factors.
In conclusion, extended reconstruction of the LAD coronary artery increase surgical risk. The procedure however may represent an option to enhances the probability for a complete revascularization in patients with an unfavourable anatomical substrate, with acceptable mid-term results. The rapid progression of the atherosclerotic disease should enhance any efforts to control risk factors in these patients whose continuous monitoring is strictly recommended. Theoretically, the more ideal flow characteristics with preservation of the endothelial function achievable reconstructing the LAD with a LIMA graft alone should be clinically tested in an effort to improve long-term patency [22].
| Acknowledgments |
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| Footnotes |
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| Appendix A. Conference discussion |
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The second question is, how do you manage them postoperatively? Do you anticoagulate them for a while or do you do something in that regard that is different from the rest of the population?
And the third thing is what you just mentioned. I do a lot of endarterectomies and I notice that putting a vein patch is not very good, so I have gone into exactly what you mentioned, anastomosing the mammary directly to the endarterectomized LAD. I don't have patencies, but it seems to work clinically very, very well. If you have a big, long enough pedicle, you can cover just about the whole LAD.
And the last question is about the patencies that you mentioned. Were they in endarterectomies alone or endarterecty plus patch?
Dr Santini: First of all, this procedure was limited to the LAD territory, so patch plus LIMA was only on the LAD coronary artery.
Dr Irarrazaval: Were grafts in other places?
Dr Santini: Of course, yes. The mean number of grafts was three per patient and it ranged between two and five.
Dr Irarrazaval: So it is clinically difficult to know whether the angina is because of the other vessels or because of the patch?
Dr Santini: Well, many of these patients get stress tests postoperatively. Although there are some limitations with this type of evaluation, in few cases the territory responsible for the symptoms could be identified on the LAD territory, and many of these times these patients were among those, with a poor runoff or occluded LAD at the postoperative angio. Only those patients with associated EA get Coumadin postoperatively for about 2 months and then they carry on just with antiplatelet drugs.
The third question, well, definitely the possibility to use the LIMA graft per se, as the only graft and as the only tool to revascularize these patients is very attractive, although, again, I think that most of the time it is very difficult to adapt the LIMA, which has a very thin wall, to an LAD, which is usually very calcified and thick, and this discrepancy can sometimes, distort the roof of these new conduits making the flow less reliable long term.
Dr B. Messmer (Aachen, Germany): One of the advantages if you take the IMA as a patch plasty, splitting it the whole length, you do not oversize, because with the IMA you cannot oversize as you can do with a vein patch. So personally I prefer up to about 3 cm to take the IMA, but over 3 cm I am too lazy to take such a length.
With regard to your angiographies, postoperative controls, how did you select those 60%? Was that just at random or was that more or less a negative selection because patients had angina afterwards, or was it just because there were patients you had that agreed for the procedure?
Dr Santini: Well, first of all I take your point as far as the mammary should be used alone just because, as we showed, the redundancy or the dilatation of the patch may be responsible for some unsuccessful long-term patency, and also because the tissue of the vein in terms of compliance is totally unpredictable. So even if you reduce the size, you cannot really predict how it is going to enlarge over time.
Basically we did not select the patients. I mean, the postoperative angio was suggested to all survivors after 6 months, and we studied the patients who accepted the procedure.
Dr A. Moritz (Frankfurt, Germany): We adopted this type of technique after the several reports from Bara, and we actually used in the LAD, or in every region we used the graft that was kind of planned to go there. So for the LAD we usually used the IMA. And what you suggested I think in our hands it worked out that you really can use the IMA as a patch anastomosis for these vessels, and we use a special hardened needle, there are some available, and this makes it possible. With the regular Prolene I think you are right that may be technically very demanding, but there are specially hardened needles you can pass through the calcium and it works out pretty well.
Dr Santini: For sure, the possibility to use the mammary alone is very attractive whether or not this solution will provide better results long-term could only come out from a prospectively randomized study, and I think this is not very feasible in these kind of patients, but I am sure that the possibility to use the mammary should be tested.
Dr Moritz: It simply saves time, too.
Dr Santini: Yes, definitely.
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