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J Am Coll Cardiol, 2000; 36:387-394 © 2000 by the American College of Cardiology Foundation |

* Unité de Cardiologie Interventionelle, Clinique Pasteur, Toulouse, France
Department of Cardiology, The Geelong Hospital, Geelong, Australia
Manuscript received June 4, 1999; revised manuscript received January 20, 2000, accepted March 29, 2000.
Reprint requests and correspondence: Dr. Jean Fajadet, Unité de Cardiologie Interventionelle, Clinique Pasteur, 45 avenue de Lombez, Toulouse 31076, France
fajadet{at}interv-cardio-toul.com
| Abstract |
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This study was designed to evaluate the immediate and long-term clinical results of patients undergoing endoluminal reconstruction in diffusely degenerated saphenous vein grafts (SVGs) with elective implantation of one or more less-shortening Wallstents.
BACKGROUND
The optimal treatment strategy for patients with diffusely degenerated SVGs is controversial. Endoluminal reconstruction by stent implantation is one proposed strategy; however, there are few data regarding long-term clinical outcome.
METHODS
Between May 1995 and September 1998, 6,534 consecutive patients underwent angioplasty in our institution, including 440 who were treated for SVG lesions. Of these, 126 (115 men, 11 women, median age 69.5 years, range: 3386 years) with old SVGs (mean age: 13 ± 5 years) diffusely degenerated stenosed or occluded (mean lesion length: 27 ± 12 mm) were treated electively with implantation of one or multiple (total 197) less-shortening Wallstents.
RESULTS
Before discharge, 13 patients (10.3%) sustained at least one major cardiovascular event, including 4 deaths (3.2%), 11 myocardial infarctions (MI) (8.7%), and 3 repeat revascularizations (target vessel = 1, nontarget vessel = 2, 2.4%). Surviving patients were followed for 22 ± 11 months: 13 patients (11.1%) died, 11 (9.4%) sustained an MI, 37 underwent angioplasty (31.6%), and 4 (3.4%) underwent bypass surgery. The estimated three-year event-free survival rates (freedom from death, and freedom from death/MI/target vessel revascularization) were (mean ± SE) 81.1 ± 7.8% and 43.2 ± 18.5%, respectively.
CONCLUSIONS
The long-term clinical outcome of patients undergoing endoluminal reconstruction in diffusely degenerated SVG is relatively poor, mainly because of a high incidence of death or MI and the frequent need for repeat angioplasty. It is unlikely that percutaneous intervention alone will provide a satisfactory or definitive solution for these patients.
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The aim of this study was therefore to evaluate the immediate and long-term clinical results of patients with diffuse SVG lesions who underwent SVG reconstruction with elective implantation of one or multiple less-shortening Wallstents.
| Methods |
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Angioplasty procedure
Angioplasty was performed via the transradial (61%), transfemoral (37%) or transbrachial (2%) approach, using 6F (17%), 7F (48%) or 8F (35%) guiding catheters. The lesion was carefully crossed using a 0.014 in. guidewire and predilated with an undersized balloon inflated generally to 34 atm for
30 s in an attempt to minimize the risk of distal embolization. In all of the study patients, Wallstents were used for SVG reconstruction. This stent is a self-expanding device whose deployment does not require high-pressure balloon inflation, and which is available in a large range of lengths (up to 50 mm) and sizes (up to 6 mm). Stents were generally chosen with a diameter 1.5 mm larger than the reference diameter of the graft and with a length 15 mm longer than the stenotic lesion. Intravascular ultrasound was not used during any implantation procedures. The arterial access sheaths were removed immediately after transradial procedures and immediately or 4 to 6 h after transfemoral procedure. Hemostasis was achieved by using the Perclose device or mechanical compression (Femostop device) for up to 2 h in patients treated via the transfemoral approach, and by radial compression with a tourniquet for 1 h in patients treated via the transradial approach.
Angiographic assessment
After intracoronary injection of isosorbide dinitrate (3 mg) and lisindomine (1 mg), reference vessel diameter, minimum lumen diameter and lesion length were calculated using an online quantitative coronary analysis (DCI Philips system, The Netherlands). The following definitions were used for angiographic assessment: diffuse degenerated graft disease = isolated lesions of >20 mm in length, or diffusely diseased segments with multiple/sequential stenoses; thrombus = circumscribed intraluminal filling defect; angiographic success = smooth lumen surface at the stent site with a final diameter stenosis <10%; distal embolization = new appearance of filling defects and/or abrupt cutoff of the vessel distal to the target lesion and/or decreased antegrade flow in the distal vessel previously patent, in the absence of an occlusion of the target lesion; no reflow = poor antegrade flow (Thrombolysis in MI [TIMI] grade
1) not explained by dissection or high-grade residual stenosis at or adjacent to the target lesion; abrupt closure = poor antegrade flow (TIMI grade
1) due to acute occlusion of the target lesion.
Anticoagulant and antiplatelet regimen
All patients except those presenting with acute MI were pretreated for at least three days with aspirin (100250 mg o.d.), ticlopidine (250 mg b.d.) and enoxaparin (100 UI/kg b.d). An intravenous bolus of heparin (70 UI/kg) was administered after arterial sheath placement and additional heparin boluses were repeated as necessary to maintain the activated clotting time between 250 and 300 s. Thirty-seven (29.4%) patients were treated with abciximab therapy, including a 0.25 mg/kg bolus initiated immediately before the procedure followed by a 0.125 µg/kg/min infusion for 12 h. After the procedure, all patients received 1 month ticlopidine (250 o.d. or b.d.) and long-term aspirin (100250 mg o.d.). In the beginning of our experience, 14 patients with intracoronary thrombus were treated by enoxaparin for one to three days after the procedure, together with aspirin and ticlopidine. After the occurrence of a major intracranial hemorrhage in one patient treated after the procedure by enoxaparin, we decided to discontinue the use of anticoagulation after PTCA.
Data collection and follow-up
Clinical, angiographic and procedural data as well as postprocedural complications were prospectively entered into a computerized database (AS400, Showcase Strategy). Clinical follow-up was performed by an experienced physician who made telephone contact with the patients or their referring physicians. Information obtained included occurrence of recurrent angina, MI (defined by the development of new Q waves or increase in the serum cardiac enzymes to more than twice the upper limit of normal), subsequent cardiac catheterizations, need for repeat PTCA or additional CABG of target and nontarget vessel and death (cardiac and noncardiac). Follow-up data were entered into the computerized database. Initial and follow-up data of the studied patients were retrospectively analyzed.
Statistical analysis
Categorical variables were expressed as percent frequencies and continuous variables as mean value ± SD, or median (range and interquartile range). Chi-square analysis or the Fisher exact test were used for comparison between groups for categorical variables where appropriate, and the Student t test was used for normally distributed continuous variables. Predictors of cardiovascular events were determined by univariate analysis. A multivariate model of predictors of adverse outcome did not have sufficient power to discriminate the events, and the data are not presented. Out-of-hospital event-free survival analysis was performed using the Kaplan-Meier method, and four hierarchical event-free survival curves were generated: (1) freedom from death; (2) freedom from death and nonfatal MI; (3) freedom from death, nonfatal MI and repeat target vessel revascularization; (4) freedom from death, nonfatal MI and any repeat coronary vessel revascularization. A p value <0.05 was considered significant.
| Results |
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In addition, one patient had transient ischemic stroke without sequelae. Eight patients (6.3%) had vascular access site complications, of which two received blood transfusion and two required surgical repair. One patient who had received abciximab therapy during PTCA had major thrombocytopenia (800 platelets/mm3), necessitating blood transfusion 24 h after the procedure, and one patient developed gastrointestinal bleeding. One hundred twenty-two patients were discharged alive (96.8%). The median hospital stay for the total cohort was 5.0 days (range 216 days, interquartile range 48 days).
Clinical events after hospital discharge. Follow-up (mean duration 21.6 ± 11.3 months) was obtained in 117 (95.9%) of the 122 discharged alive patients. After the PTCA, 57 patients had no further angina and 60 patients developed angina during follow-up, of which 60% had at least one episode of unstable angina. Table 3 lists the occurrence of major events after hospital discharge. There were 13 deaths (11%), 9 of which were cardiac and 4 noncardiac. Univariate analysis indicated that increasing age of the patients (68.0 years ± 8.1 vs. 74.9 years ± 5.3, p = 0.001) and lower ejection fraction (56.9% ± 13.9% vs. 47.0% ± 17.9%, p = 0.02) were predictors of deaths during follow-up. Six patients (5.1%) sustained a nonfatal MI. Four patients (3.4%) underwent repeat bypass surgery. Two of these four patients had unstable angina and two had stable angina before surgery. The indication for repeat surgery was severe and diffuse restenosis in two cases at 2 and 42 months, and total occlusion of the target vessel associated with progressive coronary disease in nontarget vessels at 6 months follow-up. Diabetes mellitus, hypercholesterolemia, vein graft age, previous coronary angioplasty at the stent site, abciximab treatment during the procedure, lesion length, Wallstent length per graft, and final percent diameter stenosis were not predictive of the composite of death, MI and target vessel revascularization (Table 4).
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Repeat PTCA was performed in 38 patients at a median interval of 7.6 months (range 132 months): 15 underwent repeat target vessel revascularization, 13 underwent nontarget vessel revascularization and 10 underwent both target and nontarget repeat PTCA. The indication to perform repeat target lesion angioplasty was restenosis in or adjacent to the stented graft segment in all cases, with total occlusion in three cases. Nontarget vessel revascularization was due to progressive coronary disease in nontarget vessels.
Survival and event-free survival. Survival at six months and at three years were 94.2 ± 2.2% and 81.1 ± 7.8%, respectively. Freedom from death, MI and target vessel revascularization at six months and at three years, including events ccurring during the initial hospitalization, was 79.1 ± 4.2% and 43.2 ± 18.5%, respectively (Fig. 1). At three years, only 36.2 ± 17.0% of the patients were free from death, MI, and any coronary revascularization.
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| Discussion |
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Immediate results. In our study, successful stent implantation was achieved in all cases, as in previous studies reporting the use of Wallstents for treating SVG disease (2024). The frequency of in-hospital major events including death, MI, emergency CABG or PTCA was relatively high (see Table 3) compared with previous reports (0 to 11%) (1518,20,2328). Distal embolization, observed in nine patients (7.1%), occurred relatively frequently. As serum level measurements of creatine kinase with MB fraction were not systematically performed after the procedure, some non-Q wave MIs were undoubtedly missed, resulting in an underestimate of the cardiac complication rate. In a pooled analysis of 16 studies (9), SVG balloon angioplasty was associated with a high procedural success rate (about 90%) and a lower incidence of death (<1%), MI (<3%), distal embolization (<3%) and emergency CABG (<2%). However, these findings are primarily concerned with the treatment of focal lesions, with 70% to 80% of the patients having a discrete lesion <10 to 13 mm long. In addition, in our study, patients were generally older, with advanced graft age, and our results may well be influenced accordingly. It has been well established that procedural results depend in part on the "diffuseness" of SVG disease, the age of the graft, and presence of thrombus (9).
Implantation of Palmaz-Schatz stents has been shown to decrease the incidence of adverse events (20%30% at one year) and restenosis (13%37%) compared with balloon angioplasty (15,16). However, the majority of studies of stent implantation have primarily concerned the treatment of focal lesions. Moreover, the results of the sole randomized trial published are disappointing, with a 37% restenosis rate in the stent group (18).
Our treatment strategy was initially based on an angioscopic study that found evidence of thrombus in 71% of SVGs treated by angioplasty (29), and the proved beneficial effect of the use of ticlopidine and aspirin in reducing platelet aggregation and coagulation activation during angioplasty procedures (30). Furthermore, one-third of our patients received abciximab therapy according to the assumption that patients with complex or thrombus-associated morphologies might derive additional benefit from platelet IIb/IIIa inhibition. Nevertheless, in our study we found no reduction of major coronary events in patients treated by abciximab (Table 4). This result is consistent with data from Ellis et al. (31) concerning the absence of beneficial effect of abciximab compared with placebo for patients with degenerated SVG. One might postulate that the stimulus for thrombosis in this situation was more dependent on the coagulation cascade than on platelet activation and that pretreatment with enoxaparin, aspirin and ticlopidine may be more likely to be of benefit than acute administration of IIb/IIIa inhibitors. Moreover, we used Wallstents, whose self-expanding property allows avoidance of balloon inflation for implantation and whose elastic wire mesh design would theoretically aid the entrapment of macroscopic friable SVG material.
Major bleeding and vascular complications resulted in two deaths in our study. This may have resulted in part from the aggressive antiplatelet and anticoagulant regimen that was used. However, such complications were also frequent in the other series despite different antiplatelet and anticoagulant treatments. Bleeding/vascular complications have been observed in up to 33% of patients and have been frequently related to in-hospital mortality (1518,2026,28). De Scheerder et al. (23), who performed intragraft administration of thrombolytic agents during the procedure, observed bleeding complications in 33% of patients, including two fatal hemorrhagic strokes. On the other hand, there was no clinically apparent subacute stent thrombosis in our study, contrasting with an incidence of 1% to 10% reported in the literature (1518,2026,28).
Long-term results. During the mean follow-up period of 21.6 ± 11.3 months, one-third of our patients experienced major events (death or MI) and more than one-third underwent repeat revascularization. These results are quite similar to those previously reported after SVG stent implantation, even though our series included only patients with diffuse lesions. One-year event-free survival has been reported at from 46% to 80% (1517,20,21,2628). Importantly, the most disappointing results were observed in the series of De Jaegere et al. (20), in which 52% of stent implantations (mainly Wallstents) was performed for long SVG lesions. In that study, 23% of patients developed MI and 50% underwent repeat revascularization at a median of six months after the procedure. Adverse outcome after SVG stenting has been thought to be partly related to restenosis. Angiographic follow-up revealed a restenosis rate of 17% to 37% in the series utilizing Palmaz-Schatz stents (1518,25,26,28) and 20% to 54% in those using Wallstents (2024). In our study, only symptomatic patients underwent repeat angiography, and the 59% angiographic restenosis rate was therefore likely overestimated.
Our choice to perform elective SVG "reconstruction" with long stents in order to cover segments of the grafts that were not severely narrowed was based on studies that reported a 27% to 34% rate of revascularization procedures in relation to SVG disease progression (23,25). Indeed, Ellis et al. (32) have found that 45% of recurrent ischemic events after SVG interventions result from initially untreated 40%50% stenosed sites, as compared with the 19% of events related to initially treated 40%50% stenosed segments. However, our strategy to perform SVG reconstruction with long stents might well have been partly responsible for the high incidence of restenosis we observed.
| Conclusions |
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| References |
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