Poor long-term outcomes after percutaneous coronary intervention (PCI) in chronic total occlusion (CTO) of saphenous vein grafts (SVGs) have been reported. However, limited data are available evaluating the use of modern techniques in this group. The aim of the present study was to assess the efficacy and long-term outcomes of PCI in SVG CTO with the routine use of embolic protection devices and drug-eluting stents. A retrospective cohort analysis was conducted of all consecutive patients undergoing PCI to SVG CTO from May 2002 to July 2009 at 2 centers. The indication for PCI was the presence of angina or silent ischemia with evidence of inducible ischemia after functional testing in the territory supplied by the SVG, despite optimal medical therapy. We identified 34 patients with SVG CTO. Of the 34 patients, 23 (68%) underwent successful SVG recanalization with stent implantation. An embolic protection device was used in 78% and 95% of stents implanted were drug-eluting stents. No in-hospital major adverse cardiac events occurred in the successful PCI group; one myocardial infarction occurred in the unsuccessful group. At follow-up (median 18.0 months, interquartile range 10.4 to 48.3), 1 case of myocardial infarction had occurred in the successful group. The in-stent restenosis rate was 68% (n = 13), of which 77% were focal, with target vessel revascularization in 61%. In conclusion, despite the relatively low procedural success rates, the clinical outcomes after successful PCI to SVG CTO with modern techniques were favorable. The repeat revascularization rates were high; however, graft patency was achievable in most after reintervention.
Questions remain regarding the best strategy for treating the clinical problem of saphenous vein grafts (SVGs) with chronic total occlusion (CTO). Traditionally, conventional angioplasty (“plain old balloon angioplasty”) or percutaneous coronary intervention (PCI) to SVG CTO was associated with poor success rates and a 30-day major adverse cardiac event rate of 4% to 13%. Additionally, the distal embolization rates with these procedures are about 11%, with significant creatinine kinase elevation in 43%. Survival rates of 72% to 80% and event-free survival rates of 26% to 34% at 3 years have been reported, with recurrent occlusion or restenosis at follow-up angiography in 44% to 73%. This high incidence of adverse events led to the suggestion that PCI to SVG CTO is a “challenge that is best resisted” and that an alternative such as PCI to the native vessel or redo coronary artery bypass grafting should be considered. The reliability of SVG intervention has improved using embolic protection devices and drug-eluting stents (DESs). Limited studies have reported the outcomes after PCI to SVG CTO in the contemporary interventional era with the routine use of these devices. The aim of the present study was to report the clinical outcomes after SVG CTO recanalization using DESs and embolic protection devices (EPDs) to ascertain whether this is now a feasible procedure.
Methods
We analyzed data that had been prospectively collected after PCI to SVG CTO in 34 consecutive patients presenting with recurrent symptoms of angina and silent ischemia (evidence of myocardial ischemia in the territory supplied by the SVG after functional testing), despite maximum medical therapy, in 2 institutions from May 2002 to July 2009. All patients had coronary angiographic findings showing absence of adequate collateralization to the myocardial territory of the bypassed native coronary artery and the absence of anatomic characteristics favoring attempted PCI to the native coronary artery. Therefore, a decision was made to perform PCI to the occluded SVG. During the same period, 930 patients with SVG CTO were not treated, because we favored medical therapy or treatment to the native coronary artery supplying the same territory in most patients who had evidence of myocardial ischemia.
CTO was defined as a vessel with Thrombolysis in Myocardial Infarction grade 0 flow on angiography that had been occluded for >3 months. A functional total occlusion was defined as the presence of only faint, late anterograde flow in the absence of a discernible lumen, with Thrombolysis in Myocardial Infarction grade 1 flow. Angiographic success was defined as a final residual stenosis of <20% with Thrombolysis in Myocardial Infarction grade 3 flow in a previously occluded vessel after stent implantation. Periprocedural myocardial infarction was defined as a threefold increase in creatinine kinase-MB. Slow coronary flow was defined as a decrease in anterograde blood flow (from Thrombolysis in Myocardial Infarction grade 0 to grade 2). Angiographic restenosis was defined as >50% diameter stenosis on the quantitative coronary angiogram within a previously stented segment. Target lesion revascularization was defined as repeat revascularization in the target lesion secondary to a stenosis of ≥50% within the stent or within the 5 mm proximal or distal to the stent edge. Target vessel revascularization was defined as any repeat revascularization of the target vessel. Stent thrombosis was defined on the basis of the Academic Research Consortium definitions and cumulative stent thrombosis as a combination of all episodes of stent thrombosis during follow-up.
All patients gave written informed consent for both the procedure and subsequent data collection and analysis. All patients were pretreated with aspirin (100 mg/day), and a thienopyridine (ticlopidine 250 mg twice daily or clopidogrel 75 mg/day) was started ≥5 days before the procedure. A 300-mg loading dose of clopidogrel was administered before the procedure if the patients had not been pretreated. During the procedure, the patients were given intravenous heparin as an initial 100 U/kg bolus followed by additional heparin as required to achieve a target activated clotting time of >250 seconds. After engagement of the graft with the guiding catheter, a hydrophilic wire was generally used first, followed by 1.5-mm balloon dilation to allow placement of an EPD (i.e., PercuSurge GuardWire System, Medtronic, Minneapolis, Minnesota; Filter Wire EZ, Boston Scientific, Natick, Massachusetts; or Proxis Embolic Protection System, St. Jude Medical, Minneapolis, Minnesota). A proximal protection device was preferred for procedures encompassing intervention to the distal bed, including an anastomosis and/or native vessels. A distal protection device was used first when no adequate proximal landing zone was present. The PercuSurge was the preferred protection device in most patients. If technically feasible, a proximal protection device, the Proxis, was used, and an aspiration thrombectomy device was used, where possible. In cases in which it was not possible to site an EPD, the decision of whether to continue the procedure was left at the discretion of the operator. To minimize the risk of perforation and dissection associated with use of a hydrophilic wire, we did not give excessive support to the wire using a coaxial balloon or catheter. Dedicated CTO wires and microcatheters were used at the operator’s discretion. A glycoprotein IIb/IIIa inhibitor was administered at the discretion of the operator, only after the CTO had been successfully crossed with the wire, with no evidence of coronary perforation. The procedure was then performed as usual, with predilation and stent implantation using standard techniques by way of the femoral artery, as previously described. Postdilation was performed conservatively with slightly undersized balloons to reduce the risk of distal embolization. After a successful procedure, the patients were discharged with dual antiplatelet therapy of aspirin indefinitely plus ticlopidine or clopidogrel for 12 months.
All patients were followed up at regular intervals with clinic visits or telephone interviews. Additional data were obtained from primary care physicians, referring cardiologists, or relatives, as necessary. All repeat interventions and complications were prospectively entered into a dedicated database. Clinical follow-up data were obtained for all patients. Angiographic follow-up was required by protocol for each patient 3 to 6 months after successful PCI to SVG CTO, independent of the symptom status, and was obtained for 82.6% of the patients (n = 19).
The primary end points were defined as death from any cause, myocardial infarction, target vessel revascularization, target lesion revascularization, the need for redo coronary artery bypass grafting, and major adverse cardiovascular and cerebrovascular events. Major adverse cardiovascular and cerebrovascular events were defined as a composite of all-cause death, myocardial infarction, repeat revascularization, or cerebrovascular event at any point during the in-hospital stay or during follow-up. We defined the secondary end points as the incidence of in-stent restenosis and stent thrombosis, defined as probable, possible, or definite.
All statistical analyses were performed using the Statistical Package for Social Sciences, version 16.0, statistical software (SPSS, Chicago, Illinois). Continuous variables are expressed as mean ± SD or median and interquartile range (twenty-fifth percentile to seventy-fifth percentile), as appropriate. Categorical variables are expressed as counts and percentages.
Results
Successful reopening of SVG CTO was achieved in 23 patients (67.6%) with 23 lesions, and the occluded SVG could not be reopened in 11 patients (32.4%). The baseline and clinical characteristics of the overall group, the successful PCI treatment group, and those in whom PCI to the occluded SVG was unsuccessful are listed in Table 1 .
| Variable | Overall Group (n = 34) | Successful PCI (n = 23) | Unsuccessful PCI (n = 11) |
|---|---|---|---|
| Age (years) | 64.6 ± 8.9 | 66.1 ± 9.5 | 61.4 ± 6.7 |
| Men | 30 (88%) | 19 (83%) | 11 (100%) |
| Ejection fraction (%) | 46.8 ± 8.1 | 46.7 ± 9.0 | 46.8 ± 6.3 |
| Previous myocardial infarction | 24 (71%) | 15 (65%) | 9 (82%) |
| Previous percutaneous coronary intervention | 20 (59%) | 11 (48%) | 9 (82%) |
| Cardiovascular risk factors | |||
| Hypertension | 22 (65%) | 14 (61%) | 8 (73%) |
| Hypercholesterolemia | 29 (85%) | 19 (83%) | 10 (91%) |
| Current smoker | 5 (15%) | 2 (9%) | 3 (27%) |
| Diabetes mellitus | 14 (41%) | 9 (39%) | 5 (46%) |
| Diet controlled | 3 (9%) | 3 (13%) | 0 |
| Oral hypoglycemic | 9 (27%) | 5 (22%) | 4 (36%) |
| Insulin dependent | 2 (6%) | 1 (4%) | 1 (9%) |
| Unstable angina pectoris (Canadian Cardiovascular Society class IV) | 12 (35%) | 9 (39%) | 3 (27%) |
| Stable angina pectoris (Canadian Cardiovascular Society class I–III) | 16 (47%) | 9 (39%) | 7 (64%) |
| Silent myocardial ischemia (Canadian Cardiovascular Society class 0) | 6 (18%) | 5 (22%) | 1 (9%) |
| Multivessel coronary disease | 34 (100%) | 23 (100%) | 11 (100%) |
| Renal impairment (plasma creatinine ≥1.4 mg/dl) | 2 (6%) | 2 (9%) | 0 |
| Occluded saphenous vein graft mean age (years) | 11.9 ± 5.8 | 10.9 ± 5.5 | 14.0 ± 6.1 |
In the overall group, most patients were men and were symptomatic, with stable or unstable angina. In the successful PCI SVG CTO group, most presented with stable or unstable angina. The remainder were asymptomatic but had evidence of ischemia after functional testing with a myocardial perfusion scan, dobutamine stress echocardiography, or exercise tolerance test. Most of grafts were old, and all had been occluded for >3 months at the index procedure. The CTO was an in-stent restenotic lesion in 13% (n = 3) of the successful PCI group and 9% (n = 1) of the unsuccessful PCI group. The remainder of the lesions were de novo. Occlusive lesions were anatomic in most patients (78%, n = 18, successful PCI group; 73%, n = 8, unsuccessful PCI group).
Details of the angiographic procedure are listed in Table 2 , and the in-hospital outcomes are listed in Table 3 . In the overall group, an EPD was used in 62%. The procedural time was 103.4 ± 39.5 minutes, with a fluoroscopy time of 45.1 ± 24.9 minutes and contrast volume of 315.8 ± 142.1 ml. In 2 patients, episodes of slow reflow occurred during the procedure; in 1 patient, nitroprusside was administered, resulting in improved flow. The other patient was treated with nitrate and glycoprotein IIb/IIIa inhibitor with successful improvement in coronary perfusion and no resultant periprocedural myocardial infarction. In the successful PCI group, most stents implanted were DESs (95%), with implantation of a covered stent in the remainder. An EPD was used in 78% of lesions, with a proximal protection device used in 17% and a distal protection device used in the rest. In 5 patients, an EPD was not used owing to the presence of a very distal occlusion in 2, an ostial occlusion in 2, and in-stent restenosis in 1. All patients with procedural success had Thrombolysis in Myocardial Infarction grade 3 flow at the end of the procedure. One intraprocedural complication occurred in 1 patient who had a grade III coronary perforation of the SVG caused by the stent delivery system; this patient was treated with prolonged balloon inflation and covered stent implantation (Jostent, Abbott Vascular, Abbott Park, Illinois). No in-hospital adverse events, such as myocardial infarction, acute stent thrombosis, the need for urgent coronary artery bypass grafting, or death, occurred. In the 11 patients with unsuccessful PCI, an EPD was used in 3 (27.3%). A myocardial infarction occurred in 1 patient (9.1%) and was treated medically.
| Variable | Overall Group (n = 34) | Successful PCI (n = 23) | Unsuccessful PCI (n = 11) |
|---|---|---|---|
| Glycoprotein IIb/IIIa inhibitors | 3 (9%) | 3 (13%) | 0 |
| Multivessel stenting | 11 (32%) | 7 (30%) | 4 (36%) |
| Total drug-eluting stents used | 56 | 56 | 0 |
| Drug-eluting stent type | |||
| Sirolimus-eluting stent | 21 (37%) | 21 (37%) | 0 |
| Paclitaxel-eluting stent | 29 (52%) | 29 (52%) | 0 |
| Everolimus-eluting stent | 2 (4%) | 2 (4%) | 0 |
| Zotarolimus-eluting stent | 3 (5%) | 3 (5%) | 0 |
| Biolimus-eluting stent | 1 (2%) | 1 (2%) | 0 |
| Covered pericardium stent | 2 (3%) | 2 (3%) | 0 |
| Covered polytetrafluoroethylene stent | 1 (2%) | 1 (2%) | 0 |
| Total stent length (mm) | 93.6 ± 56.5 | 93.6 ± 56.5 | 0 |
| Final stent minimal luminal diameter (mm) | 2.9 ± 0.9 | 2.9 ± 0.9 | 0 |
| Number of stents per saphenous vein grafts | 2.6 ± 1.5 | 2.6 ± 1.5 | 0 |
| Dedicated chronic total occlusions wire used | 21 (62%) | 15 (65%) | 6 (29%) |
| Microcatheter used | 8 (23%) | 7 (30%) | 1 (9%) |
| Embolic protection device used | 21 (62%) | 18 (78%) | 3 (27%) |
| PercuSurge | 15 (71%) | 14 (78%) | 1 (33%) |
| FilterWire | 1 (5%) | 1 (5%) | 0 |
| Proxis | 5 (24%) | 3 (17%) | 2 (67%) |
| Aspiration thrombectomy | 16 (47%) | 15 (65%) | 1 (9%) |
| Fluoroscopy time (min) | 45.1 ± 24.9 | 47.1 ± 27.8 | 38.6 ± 11.0 |
| Procedural time (min) | 103.4 ± 39.5 | 107.7 ± 40.3 | 92.5 ± 40.9 |
| Contrast media injected (ml) | 315.8 ± 142.1 | 324.5 ± 150.7 | 288.6 ± 40.9 |
| In-laboratory complications | 1 (5%) | 1 (4%) | 0 |
| Variable | Overall Group (n = 34) | Successful PCI (n = 23) | Unsuccessful PCI (n = 11) |
|---|---|---|---|
| In hospital | |||
| Myocardial infarction | 1 (3%) | 0 | 1 (9%) |
| Acute stent thrombosis | 0 | 0 | 0 |
| Redo coronary artery bypass grafting | 0 | 0 | 0 |
| Death | 0 | 0 | 0 |
| Clinical outcomes | |||
| Follow-up (mo) | 16.4 (10.0–47.8) | 18.0 (10.4–48.3) | 14.4 (5.4–32.0) |
| Dual antiplatelet therapy (mo) | 16.4 (12.0–48.9) | 16.6 (12.0–52.1) | 14.9 (7.3–45.7) |
| Angina pectoris Canadian Cardiovascular Society class | |||
| Unstable angina (class IV) | 0 | 0 | 0 |
| Stable angina (class I–III) | 14 (41%) | 8 (35%) | 6 (55%) |
| Asymptomatic (class 0) | 20 (59%) | 15 (65%) | 5 (45%) |
| Total death | 3 (9%) | 0 | 3 (27%) |
| Cardiac death | 3 (9%) | 0 | 3 (27%) |
| Myocardial infarction | 1 (3%) | 1 (4%) | 0 |
| Cerebrovascular event | 0 | 0 | 0 |
| Redo coronary artery bypass grafting | 0 | 0 | 0 |
| Target lesion revascularization | 14 (41%) | 14 (61%) | 0 |
| Target vessel revascularization | 14 (41%) | 14 (61%) | 0 |
| Definite stent thrombosis | 1 (3%) | 1 (4%) | 0 |
| Major adverse cardiac and cerebrovascular event | 17 (50%) | 14 (61%) | 3 (27%) |
| Angiographic outcomes | |||
| Angiographic follow-up obtained | 21 (62%) | 19 (83%) | 2 (18%) |
| Restenosis | 13 (54%) | 13 (68%) | 0 |
| Restenosis type | |||
| Focal | 10 (77%) | 10 (77%) | 0 |
| Diffuse | 0 | 0 | 0 |
| Occlusive | 3 (23%) | 3 (23%) | 0 |
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