Palmaz-Schatz stenting for treatment of focal vein graft stenosis: immediate results and long-term outcome

Percutaneous coronary interventions on vein graft bifurcation lesions presenting as an acute coronary syndrome

Interventions on graft bifurcation lesions are uncommon, especially in the setting of acute coronary syndromes (ACS). We described three cases of graft bifurcation intervention where we tailored our approach based on lesion characteristics, anatomy, and angulation to achieve excellent angiographic and clinical outcomes. In case 1, shared ostia of saphenous vein graft (SVG) to Diagonal (D) and Radial graft to Obtuse Marginal (OM) was severely stenosed. We prioritized the radial arterial graft as it is known to have a longer patency rate over a totally occluded SVG of an undetermined period. We performed provisional stenting of the ostium of the radial artery and balloon angioplasty of the SVG ostium, while stenting the body of the SVG. In case 2 (bifurcation lesion at the anastomosis of SVG to D1 and sequential jump graft to OM), we utilized a V stenting strategy after an embolization protection device (EPD) was deployed in the branch with a suitable landing zone. Kissing balloon dilatation of both the branches was performed both pre- and poststenting. In case 3 (bifurcation lesion at SVG to OM and Sequential "T" graft to diagonal), there was >90% angulation between both the grafts. We used "T" stenting strategy in this case. At 2-year follow-up, patients had no major adverse cardiovascular events since and remained symptom free.

Care of the Post-CABG Patient

An estimated 400,000 coronary artery bypass graft operations are performed annually in the United States. Saphenous vein grafts are the most commonly used conduits; however, graft failure is common. In contrast, left internal mammary artery grafts have more favorable long-term patency rates. Guidelines recommend aggressive secondary prevention. In the 2 decades following surgery, 16% of patients require repeat revascularization, and percutaneous coronary intervention accounts for 98% of procedures performed. Post-coronary artery bypass graft patients presenting with symptoms of acute coronary syndrome or progressive heart failure should undergo early coronary angiography given the high likelihood that such a presentation represents graft failure. Percutaneous coronary intervention in degenerated saphenous vein grafts is associated with embolization that may cause the "no-reflow phenomenon," which can be avoided with the use of embolic protection devices. Hybrid revascularization procedures are a promising emerging strategy to avoid the placement of vein grafts.

Drug-Eluting Stents Versus Bare Metal Stents in Saphenous Vein Graft Intervention

Percutaneous coronary intervention (PCI) of saphenous vein graft (SVG) is associated with higher adverse event rates, lower procedural success, and inferior longterm patency rates compared with native vessel PCI. The ability to comply with dual antiplatelet therapy, and whether the patient will need an interruption in dual antiplatelet therapy, should be considered when deciding whether to implant a drug-eluting stent (DES) or bare metal stent (BMS) in an SVG. DES should be used for SVG PCI because they seem to reduce target vessel revascularization. This article reviews the evolution and contemporary evidence regarding use of DES versus BMS in SVG PCI.

[Saphenous graft angioplasty]

In our daily practice the rate of saphenous graft angioplasty is less than 5%. This kind of angioplasty is more complex with a higher rate of complications in known fragile patients. Some technical trips and tricks are necessary to easily perform these angioplasties. Main difficulties are the extension of saphenous graft lesions, the risk of distal embolism, coronary slow or no flow and the high rate of restenosis. Pharmacological treatment is disappointing with no efficacy of the Gp IIb-IIa blockers. Otherwhise the use of protection devices is clearly effective and must be used when it is technically possible. With the use of bare metal stents in saphenous graft angioplasty the rate of restenosis is very high. There are some encouraging results with drug eluting stents. But we are still now not allowed to use them in this indication in our daily practice.

Early invasive strategy improves outcomes in patients with acute coronary syndrome with previous coronary artery bypass graft surgery: a report from TACTICS-TIMI 18

BACKGROUND

Patients with previous coronary artery bypass graft surgery (CABG) have been classified as a high-risk subset of patients who experience non-ST elevation acute coronary syndrome (ACS). Recent studies suggest that an early invasive strategy is beneficial in moderate- and high-risk patients with non-ST elevation ACS. We hypothesized that an early invasive strategy is associated with improved outcomes in patients with non-ST elevation ACS with prior CABG.

METHODS AND RESULTS

In the Treat Angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy-Thrombolysis in Myocardial Infarction 18 trial (TACTICS-TIMI 18), 2220 patients with non-ST segment elevation ACS were randomized to an early invasive or conservative (selectively invasive) strategy. All patients were treated with aspirin, heparin, and tirofiban. Four hundred eighty-four (22%) of these patients had undergone CABG before enrollment. We analyzed whether patients with previous CABG had different 6-month outcomes and whether an early invasive strategy was associated with an improvement in long-term outcomes. Prior CABG was associated with a higher risk of adverse outcomes by 6 months, including a higher rate of readmission for ACS (17.4% vs 11.0%, P < 0.001) and a higher incidence of the composite end point of death, myocardial infarction, or rehospitalization for ACS (22.3% vs 16.4%, P = 0.002). There was a trend toward a higher incidence of myocardial infarction (7.1% vs 5.3%, P = 0.051). An early invasive strategy was associated with a reduction in the composite of death or myocardial infarction (odds ratio [OR], 0.58; 95% confidence interval [CI], 0.31-1.0; P = 0.089) and a significant reduction in the incidence of myocardial infarction at 6 months (OR, 0.44; 95% CI, 0.21-0.93; P=0.032).

CONCLUSIONS

Patients with non-ST segment elevation ACS who have had previous CABG are a high-risk subset. An early invasive strategy reduces risk of myocardial infarction in this high-risk group.

Percutaneous coronary intervention of or through saphenous vein grafts or internal mammary arteries: the impact of stents, adjunctive pharmacology, and multicomponent distal protection

We hypothesized that the use of stents and aggressive adjunctive pharmacotherapies has been associated with lower rates of complicating myocardial infarction (MI) and improved long-term outcomes compared to either previous balloon-only percutaneous coronary intervention (PCI) or atheroablative intervention for lesions of or through saphenous vein grafts (SVGs) and/or internal mammary arteries (IMAs). PCI of SVG has been complicated by relatively high rates of procedural MI and less favorable long-term outcomes than native vessel PCI, stimulating the development and application of an array of technologies. This study was based on retrospective review of stent-era (1999-2004) 5-year experience of a single center with 95 SVG procedures in 85 patients and 20 IMA procedures in 20 patients. These cases were compared with the previously published experience of one of the operators during the balloon-only period and literature review of the application of multiple technologies to SVG intervention, as well as consideration of the reoperation alternative. There was one in-hospital death each in the SVG cohort (1%) and in the IMA cohort (5%). There were SIX procedural MIs (6%), defined by total CK > normal, and 19 procedural MIs (20%) based on troponin-I > 1.0. Follow-up has been from 4 months to 5 years (average, 2.5 years), with 91% survival and one late CABG in the IMA group. SVG PCI with stents and adjunctive pharmacotherapies is associated with relatively low rates of procedural MI and favorable long-term outcomes.

Opportunities for gene therapy in preventing vein graft failure after coronary artery bypass surgery

The poor patency rates for coronary artery bypass grafting (CABG) using autologous saphenous vein necessitate the need for continued research into the potential clinical utility of gene therapy. Bypass grafting is ideally suited for gene therapy, as graft can be genetically modified ex vivo prior to grafting in the coronary vasculature. Research to date has demonstrated effective blockade of late vein graft failure through overexpression of a variety of transgenes that modulate the proliferative, migratory and/or apoptotic indexes of cells in the graft wall. This has resulted in a substantial wealth of preclinical data that support advancement to clinical trials. Future translation into clinical trials will ensure that this exciting and highly relevant area of gene therapy is fully evaluated for potential routine clinical practice to improve patency rates of bypass graft procedures involving saphenous vein.

Drug-Eluting Coronary Stents

The introduction and widespread use of coronary stents have been the most important advancement in the percutaneous treatment of coronary artery disease since the introduction of balloon angioplasty. Coronary artery stents reduce the rate of angiographic and clinical restenosis compared to balloon angioplasty. This angiographic restenosis was further reduced with the introduction of drug-eluting stents and hence further reduction in the frequency of major adverse cardiac events. Herein we present a comprehensive and up-to-date review about the use of drug-eluting stents in the treatment of coronary artery disease.

Randomized study to compare balloon angioplasty and elective stent implantation in venous bypass grafts: the Venestent study

The aim of the study was to compare acute and long-term angiographic and clinical outcome of balloon angioplasty and elective stenting in de novo lesions in the body of a saphenous vein graft (SVG). A total of 150 patients, with de novo lesions in SVG, were randomly assigned to balloon angioplasty or elective Wiktor I stent implantation. The angiographic restenosis rate at 6-month follow-up was 32.8% in the balloon group and 19.1% in the stent group (P = 0.069). At 1-year follow-up, target vessel revascularization rate was 31.4% vs. 14.5% (P < 0.05), and event-free survival was 60.0% vs. 76.3% (P < 0.05) for the balloon and stent group, respectively. Elective stent implantation in de novo SVG lesions is associated with a significant lower target vessel revascularization rate and a significant higher event-free survival at 1-year follow-up as compared to balloon angioplasty.

Effect of direct stenting on clinical outcome in patients treated with percutaneous coronary intervention on saphenous vein graft

BACKGROUND

Percutaneous coronary intervention (PCI) of saphenous vein graft (SVG) is associated with frequent postprocedural enzyme elevation and late cardiac events. New strategies are proposed to minimize distal embolization and to improve the outcome of patients treated with stenting for SVG lesions. The objectives of the current study were to examine direct stenting (DS) strategy of PCI in SVG lesions and its effects on creatine-kinase (CK) release, major adverse cardiac events (MACE), and late outcome when compared to conventional stenting (CS).

METHODS

A consecutive series of 527 patients treated with stent implantation for SVG stenosis was analyzed. In this cohort, 170 patients with 229 lesions were treated with DS and 357 patients with 443 lesions were treated with CS. The inhospital and 12-month follow-up events were recorded and reported.

RESULTS

Baseline clinical and postprocedural angiographic characteristics were similar between the 2 groups except for higher preprocedural prevalence of thrombus-containing lesions in the DS group. Patients in the DS group had less CK-MB release (P <.001), and less non-Q-wave myocardial infarction (P =.024). Multivariate analysis detected unstable angina (odds ratio [OR] = 1.8, P =.03) as a correlate for non-Q-wave MI; DS was inversely associated with non-Q-wave myocardial infarction (OR = 0.65, P =.04). At 1 year, the target lesion revascularization-MACE was significantly lower in the DS group (P =.021). Multivariate analysis showed that DS (OR = 0.47, P =.007) was associated with reduction of the target lesion revascularization-MACE.

CONCLUSIONS

When feasible, DS may be the best approach for treating SVG stenosis.

Usefulness of beta radiation for de novo and in-stent restenotic lesions in saphenous vein grafts

Following successful angioplasty of 49 saphenous vein graft lesions, a novel, self-centering phosphorus-32 solid foil beta source encapsulated within a dual-balloon membrane was used to deliver 20 Gy 1 mm into the vessel wall. Clinical and angiographic recurrence rates at 12 months were low, especially in de novo lesions.

Randomized evaluation of polytetrafluoroethylene-covered stent in saphenous vein grafts: the Randomized Evaluation of polytetrafluoroethylene COVERed stent in Saphenous vein grafts (RECOVERS) Trial

BACKGROUND

Treatment of lesions located in saphenous vein grafts (SVGs) is associated with increased procedural risk and a high rate of restenosis.

METHODS AND RESULTS

We conducted a randomized, multicenter trial to evaluate the usefulness of a polytetrafluoroethylene (PTFE)-covered stent compared with a bare stainless steel (SS) stent for prevention of restenosis and major adverse cardiac events (MACE) in patients undergoing SVG treatment. The primary end point was angiographic restenosis at 6 months. Secondary end points were 30-day and 6-month MACE rates, defined as the cumulative of death, myocardial infarction (MI), and target lesion revascularization. Between September 1999 and January 2002, 301 patients with SVG lesions were randomized to either the PTFE-covered JoStent coronary stent graft (PTFE group, n=156) or the SS JoFlex stent (control group, n=145). Angiographic and procedural success rates were similar between the 2 groups (97.4% versus 97.9% and 87.3% versus 93.8%, respectively). The incidence of 30-day MACE was higher in the PTFE group (10.9% versus 4.1%, P=0.047) and was mainly attributed to MI (10.3% versus 3.4%, P=0.037). The primary end point, the restenosis rate at 6-month follow-up, was similar between the 2 groups (24.2% versus 24.8%, P=0.237). Although the 6-month non-Q-wave MI rate was higher in the PTFE group (12.8% versus 4.1%, P=0.013), the cumulative MACE rate was not different (23.1% versus 15.9%, P=0.153).

CONCLUSIONS

The study did not demonstrate a difference in restenosis rate and 6-month clinical outcome between the PTFE-covered stent and the SS stent for treatment of SVG lesions. However, a higher incidence of nonfatal myocardial infarctions was found in patients treated with the PTFE-covered stent.

Comparison of intracoronary gamma radiation for in-stent restenosis in saphenous vein grafts versus native coronary arteries

Intracoronary gamma radiation is effective in reducing recurrent in-stent restenosis (ISR) involving native coronary arteries. This study compares the effectiveness and safety of intracoronary gamma radiation for the treatment of ISR in saphenous vein grafts (SVGs) versus native coronary arteries. In the Washington Radiation for In-Stent restenosis Trial (WRIST) series of gamma radiation trials, 1,142 patients with ISR (230 in SVG and 912 in native coronary arteries) completed 6-month clinical follow-up. All patients underwent balloon angioplasty, atherectomy, and/or restenting. Different ribbon lengths containing 6 to 23 seeds of iridium-192 were used to cover lesion lengths <80 mm. The prescribed radiation doses were 14 or 15 Gy at 2-mm radial distance from the center of the source. Baseline demographics showed that patients with SVGs were older (65 +/- 13 vs 61 +/- 11 years, p <0.001), more likely male (79% vs 64%, p <0.001), had more multivessel coronary disease (81% vs 50%, p <0.001), and less diffuse lesions (17 +/- 10 vs 24 +/- 12 mm, p <0.001). At 6 months, event-free survival was similar for patients with SVG ISR and native coronary ISR (82% vs 84%, p = 0.35). The SVG ISR population had a low rate of late total occlusion (4.6%) and late thrombosis (3.5%). Thus, treatment of ISR with gamma radiation in SVGs had similar outcome to native coronary arteries. The use of gamma radiation for the treatment of ISR should expand to SVGs.

Percutaneous coronary intervention versus repeat bypass surgery for patients with medically refractory myocardial ischemia: AWESOME randomized trial and registry experience with post-CABG patients

OBJECTIVES

This report compares long-term percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) survival among post-CABG patients included in the Angina With Extremely Serious Operative Mortality Evaluation (AWESOME) randomized trial and prospective registry.

BACKGROUND

Repeat CABG surgery is associated with a higher risk of mortality than first-time CABG. The AWESOME is the first randomized trial comparing CABG with PCI to include post-CABG patients.

METHODS

Over a five-year period (1995 to 2000), patients at 16 hospitals were screened to identify a cohort of 2,431 individuals who had medically refractory myocardial ischemia and at least one of five high-risk factors. There were 454 patients in the randomized trial, of whom 142 had prior CABG. In the physician-directed registry of 1,650 patients, 719 had prior CABG. Of the 327 patient-choice registry patients, 119 had at least one prior CABG. The CABG and PCI survivals for the three groups were compared using Kaplan-Meier curves and log-rank tests.

RESULTS

The CABG and PCI three-year survival rates were 73% and 76% respectively for the 142 randomized patients (75 and 67 patients) (log-rank = NS). In the physician-directed registry, 155 patients were assigned to reoperation and 357 to PCI (207 received medical therapy); 36-month survivals were 71% and 77% respectively (log-rank = NS). In the patient-choice registry, 32 patients chose reoperation and 74 chose PCI (13 received medical therapy); 36-month survivals were 65% and 86% respectively (log-rank test p = 0.01).

CONCLUSIONS

Percutaneous coronary intervention is preferable to CABG for many post-CABG patients.

Percutaneous intervention for atherosclerotic disease in saphenous vein grafts

The long term benefit of coronary artery bypass surgery (CABG) is limited by development of atherosclerotic disease in the bypass conduits. Percutaneous revascularisation is frequently the preferred method of treated symptomatic saphenous vein graft (SVG) atherosclerotic disease. The immediate and long term results of percutaneous intervention for SVGs is reviewed. Therapeutic considerations as well as novel technical advances are overviewed

Intravascular gamma radiation for in-stent restenosis in saphenous-vein bypass grafts

BACKGROUND

Intracoronary radiation therapy is effective in reducing the recurrence of in-stent stenosis in native coronary arteries. We examined the effects of intravascular gamma radiation in patients with in-stent restenosis of saphenous-vein bypass grafts.

METHODS

A total of 120 patients with in-stent restenosis in saphenous-vein grafts, the majority of whom had diffuse lesions, underwent balloon angioplasty, atherectomy, additional stenting, or a combination of these procedures. If the intervention was successful, the patients were randomly assigned in a double-blind fashion to intravascular treatment with a ribbon containing either iridium-192 or nonradioactive seeds. The prescribed dose, delivered at a distance of 2 mm from the source, was 14 to 15 Gy in vessels that were 2.5 to 4.0 mm in diameter and 18 Gy in vessels with a diameter that exceeded 4.0 mm. The primary end points were death from cardiac causes, Q-wave myocardial infarction, revascularization of the target vessel, and a composite of these events at 12 months.

RESULTS

Revascularization and radiation therapy were successfully accomplished in all patients. At six months, the restenosis rate was lower in the 60 patients assigned to the iridium-192 group than in the 60 assigned to the placebo group (21 percent vs. 44 percent, P=0.005). At 12 months, the rate of revascularization of the target lesion was 70 percent lower in the iridium-192 group than in the placebo group (17 percent vs. 57 percent, P<0.001), and the rate of major cardiac events was 49 percent lower (32 percent vs. 63 percent, P<0.001).

CONCLUSIONS

The results of our study support the use of gamma-radiation therapy for the treatment of in-stent restenosis in patients with bypass grafts.

Long-term clinical outcome and predictors of major adverse cardiac events after percutaneous interventions on saphenous vein grafts

OBJECTIVES

The purpose of this study was to examine the long-term clinical outcome after percutaneous intervention of saphenous vein grafts (SVG) and to identify the predictors of major adverse cardiac events (MACE).

BACKGROUND

Percutaneous interventions of SVGs have been associated with more procedural complications and higher restenosis rates compared with interventions on native vessels.

METHODS

From 1993 to 1997, 1,062 patients underwent percutaneous intervention on 1,142 SVG lesions. Procedural, in-hospital and long-term clinical outcomes were recorded in a database and analyzed.

RESULTS

In-hospital MACE occurred in 137 patients (13%) including death (8%), Q-wave myocardial infarction (MI) (2%) and coronary artery bypass surgery (3%). Late MACE occurred in 565 patients (54%) including death (9%), Q-wave MI (9%) and target vessel revascularization (36%). Any MACE occurred in 457 (43%) patients. Follow-up was available in 1,056 (99%) patients at 3 +/- 1 year. Univariate predictors were restenotic lesion (odds ratio [OR]: 2.47, confidence interval [CI]: 1.13 to 3.85, p = 0.0003), unstable angina (OR: 1.99, CI: 1.27 to 2.91, p = 0.04) and congestive heart failure (CHF) (OR: 1.97, CI: 1.14 to 3.24, p = 0.02) for in-hospital MACE, and peripheral vascular disease (PVD) (OR: 2.18, CI: 1.34 to 3.44, p = 0.002), intra-aortic balloon pump placement (OR: 2.08, CI: 1.13 to 3.85, p = 0.02) and previous MI (OR: 1.97, CI: 1.14 to 3.25, p = 0.007) for late MACE. Independent multivariate predictors for late MACE were restenotic lesion (relative risk [RR] 1.33, p = 0.02), PVD (RR: 1.31, p = 0.01), CHF (RR: 1.42, p = 0.01) and multiple stents (RR: 1.47, p = 0.004). Angiographic follow-up was available for 422 patients. Angiographic restenosis occurred in 122 (29%) of stented SVGs and 181 (43%) of nonstented SVGs (p = 0.04). Stent implantation did not confer a survival benefit.

CONCLUSIONS

Despite the use of new interventional devices, SVG interventions are associated with significant morbidity and mortality; SVG stenting is not associated with better three-year event-free survival. This may be due to progressive disease at nonstented sites.

Short-term outcome of stent implantation in saphenous vein grafts: predictors of distal embolization and restenosis

The present study, which aimed to determine the predictors of distal embolization and restenosis after stenting for vein graft disease, retrospectively analyzed 51 consecutive patients who underwent stent implantation for diseased saphenous vein grafts. Follow-up angiography was performed 6 months after the procedure and the clinical and angiographic variables were analyzed by multivariate logistic regression to determine the predictors of distal embolization and restenosis. Initial clinical success was achieved in 49 patients, 44 of whom underwent follow-up angiography and were enrolled in the retrospective analysis. Distal embolization occurred in 6 grafts (13.6%). Multivariate analysis showed that the lesion length and the total cholesterol level were independent predictors of distal embolization. Angiographic restenosis occurred in 13 (26.5%) of 49 lesions. The minimum luminal diameter and the percent diameter stenosis after stenting were associated with the occurrence of restenosis. Multivariate analysis of lesions located in the graft body identified graft age as an independent predictor of restenosis. Distal embolization can occur after vein graft stenting, especially in patients with hypercholesterolemia and diffuse stenosis. The post-stenting minimum luminal diameter and the percent diameter stenosis are predictors of restenosis. In particular, graft age is associated with the restenosis of graft body lesions.

Risk factors for the development of restenosis following stent implantation of venous bypass grafts

OBJECTIVE

To analyse the variables involved in the high restenosis rate following stent implantation in coronary artery bypass grafts.

DESIGN

A retrospective analysis of a consecutive group of patients attending a tertiary centre.

PATIENTS

The long term angiographic outcome of 219 stent implantations for individual lesions performed in 191 patients was investigated. Multivariate analysis correlated clinical, procedural, and angiographic variables with the incidence of angiographic restenosis, defined as diameter stenosis > 50% at follow up.

RESULTS

Angiographic restenosis was observed in 34% of lesions treated. Multiple logistic regression analysis defined diabetes mellitus (odds ratio 6.91, 95% confidence interval (CI) 2.43 to 9.69), graft recanalisation (2.89, 95% CI 1.18 to 6.63), lesion at the aortic anastomosis (6.98, 95% CI 2.77 to 21.31), lesion at the coronary anastomosis (3.01, 95% CI 1.19 to 7.69), high diameter stenosis after stent placement (7.21, 95% CI 2.66 to 16.81), placement of long stents (2.73, 95% CI 1.09 to 7.39), and implantation of more than one stent (7.31, 95% CI 2.08 to 19.96) as independent predictors of graft in-stent restenosis.

CONCLUSIONS

There appears to be a specific risk factor constellation contributing to the high restenosis rate following stent implantation in venous bypass grafts. Critical consideration of these variables may help identify patients who are poor candidates for stent implantation and who may benefit from a different approach.

Ultrasound thrombolysis in stent thrombosis

Recent refinement in stent implantation technique and peri-procedural pharmacological treatment has lowered the incidence of stent thrombosis significantly. Still, all stent thromboses are associated with major adverse events. In previous studies it has been suggested that intravascular ultrasound fibrinolysis is safe and effective. In this report, ultrasound successfully reperfused thrombotically occluded stents. These observations suggest that ultrasound may dissolve occlusive platelet-rich thrombus effectively and safely. Cathet. Cardiovasc. Intervent. 51:332-334, 2000.

Influence of diabetes mellitus on early and late clinical outcomes in saphenous vein graft stenting

OBJECTIVES

The purpose of this study was to compare early and late clinical outcomes in diabetic and nondiabetic patients after stent implantation in saphenous vein grafts (SVG).

BACKGROUND

Patients with diabetes mellitus have less favorable acute and long-term outcomes after stent implantation in native coronary arteries. The impact of diabetes on SVG stenting, however, is not known.

METHODS

We studied 908 consecutive patients (1,366 SVG lesions) treated with Palmaz-Schatz stents. In-hospital and late clinical outcomes (death, Q-wave myocardial infarction and repeat revascularization rates at one year) were compared between diabetic (n = 290) and nondiabetic (n = 618) patients.

RESULTS

In-hospital mortality was significantly higher in diabetic as compared with nondiabetic patients (2.2% vs. 0.3%, p = 0.003). At one-year follow-up, target lesion revascularization (TLR) was 16.6% in diabetic and 12.3% in nondiabetic patients (p = 0.03). Overall cardiac event-free survival (freedom from death, Q-wave myocardial infarction and any coronary revascularization procedure) at one year was significantly lower in the diabetic (68%) compared with the nondiabetic patients (79%, p = 0.0003). By Cox regression analysis, diabetes mellitus was an independent predictor of both TLR (relative risk: 1.23; confidence interval: 0.96 to 1.58; p = 0.004) and late cardiac events (relative risk: 1.40; confidence interval: 1.05 to 1.86; p = 0.02).

CONCLUSIONS

Patients with diabetes undergoing stent implantation in SVG have: 1) higher in-hospital and late mortality, 2) higher one-year TLR rates, and 3) significantly lower one-year cardiac event-free survival. Thus, diabetic patients have less favorable acute and late clinical outcomes after stent implantation in SVG lesions.

Stent placement for non-STRESS/BENESTENT lesions: a critical review

Stenting lesions with favorable characteristics as required for inclusion in the STRESS/BENESTENT trials have yielded superior results to that of PTCA alone. Results for less favorable lesions such as in small vessels, diffuse disease, ostial disease, and saphenous vein grafts are less well established. This review seeks to analyze available data for stent placement in this subset of non-STRESS/BENESTENT lesions.

Long-term clinical results after stent implantation in old obstructed saphenous vein grafts

STUDY OBJECTIVE

To assess the long-term clinical outcome of treating patients with coronary artery disease and obstructed saphenous vein grafts (SVGs) with stents deployed by oversized balloon catheters.

DESIGN

The study included 89 of 92 consecutive patients who had 121 SVG stent implants (average, 1.4 stents per patient). We aimed at achieving a negative stenosis using oversized balloons to achieve a catheter to artery ratio of 1.1:1, and a 100% follow-up at 24+/-14 months (range, 0 to 54 months) was achieved.

PATIENTS

As 3 of 92 patients died during hospital admission, the study follow-up population consisted of 89 of 92 patients (mean age, 67+/-10 years). The age of the SVGs was 10+/-4 years.

RESULTS

We implanted 118 Palmaz-Schatz and 3 Gianturco-Roubin stents. Procedural success was achieved in 87 of 92 patients (94.5%; < 50% stenosis, and no death, Q-wave acute myocardial infarction, or coronary artery bypass graft [CABG]). Mean SVG stenosis diameter was reduced from 80+/-13% to -11+/-12% (p<0.001) and mean luminal diameter increased from 0.6+/-0.5 mm to 3.3+/-0.8 mm (p<0.001). At follow-up, angina pectoris had developed in 42 of 89 patients (47%), acute myocardial infarction in 12 of 89 patients (14%), reperformed CABG in 12 of 89 patients (14%), cardiac death in 10 of 89 patients (11%), and unrelated death in 6 of 89 patients (7%). Coronary angiography was performed in 37 of 89 patients (42%), with restenosis in 16 of 37 patients (43%) and disease progression at other sites in 11 of 37 patients (30%). Only 25 of 89 patients (28%) experienced event-free survival at follow-up.

CONCLUSIONS

Despite high procedural success and excellent angiographic results with oversized balloon catheters, the long-term clinical outcome of SVG stent implantation is suboptimal.

A comparison of short- and long-term outcomes for balloon angioplasty and coronary stent placement

OBJECTIVES

We sought to compare patient outcomes for coronary stent placement and balloon angioplasty.

BACKGROUND

Since 1994, the number of patients treated only with balloon angioplasty has decreased nationally, whereas the use of coronary stents as an alternative has grown tremendously. The objectives of this study were to compare short- and long-term survival and subsequent revascularization rates for patients undergoing single-vessel balloon angioplasty and coronary stent placement.

METHODS

New York's Coronary Angioplasty Registry was used to identify New York patients undergoing either balloon angioplasty or stent placement between July 1, 1994, and December 31, 1996. Statistical models were used to compare risk-adjusted short- and long-term survival and subsequent coronary artery bypass graft surgery (CABG) and percutaneous coronary interventions (PCIs).

RESULTS

No significant differences were found in adjusted in-patient mortality, but patients who had balloon angioplasty were, on average, 1.36 times more likely to have died at any time during the two-year period after the index procedure (p = 0.003). The adjusted in-patient CABG rate was significantly higher for balloon angioplasty (2.72% vs. 1.66%, p<0.0001), and the adjusted two-year CABG rate was also significantly higher for balloon angioplasty (10.81% vs. 7.25%, p<0.001). The adjusted two-year rate for subsequent PCIs was also significantly higher for balloon angioplasty (19.6% vs. 14.3%, p<0.0001). Although measures were taken to eliminate or minimize the effect of selection bias, it should be noted that patients with stents were healthier at hospital admission than patients who had balloon angioplasty.

CONCLUSIONS

Stent placement is associated with significantly lower risk-adjusted long-term mortality, CABG and subsequent PCI rates, as compared with balloon angioplasty.

Long-term clinical outcome after endoluminal reconstruction of diffusely degenerated saphenous vein grafts with less-shortening wallstents

OBJECTIVES

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: 33-86 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.

Procedural results and intermediate clinical outcomes after multiple saphenous vein graft stenting

OBJECTIVES

We evaluated the early and mid-term (18-month) clinical events in a consecutive series of patients undergoing a nonstaged multiple saphenous vein grafting (SVG) intervention with stents as compared with a single SVG stent procedure.

BACKGROUND

Saphenous vein graft angioplasty has been limited by high rates of distal embolization, myocardial infarction, restenosis and late mortality. It is unknown whether stenting of multiple, different SVGs at the same setting is associated with higher risk.

METHODS

We evaluated in-hospital and mid-term clinical outcomes (death, Q wave myocardial infarction [MI] and repeat revascularization rates up to 18 months) in 70 consecutive patients treated with coronary stents in 2 (93% of patients) or 3 SVGs, as compared with 649 patients undergoing stenting of a single SVG between January 1, 1994 and December 31, 1997.

RESULTS

Overall procedural success was obtained in 97% of patients with 2 or 3 SVGs and 97% of patients with a single SVG (p = 0.94). Procedural complications were also similar (2.8% for multiple SVGs vs. 2.7% for a single SVG, p = 0.94). There was a higher prevalence of periprocedural non-Q wave MI (28% vs. 16%, p = 0.009) in the multiple SVG group. During follow-up (18 months), target lesion revascularization was 11% in multiple SVG and 15% in single SVG interventions (p = 0.19), and repeat revascularization (calculated per treated patient) was also similar for both groups (19% vs. 18%, p = 0.94). There was no difference in death (5.6% vs. 5.3%, p = 0.92) and Q wave MI rate (4.3% vs. 2.9%, p = 0.55) after the multiple SVG intervention. Overall cardiac event-free survival was similar for both groups (62% vs. 60%, p = 0.75). The study was powered to detect a clinically meaningful difference of 10% in mortality; smaller differences could not be evaluated on the basis of this sample size.

CONCLUSIONS

Simultaneous stenting of multiple SVGs in carefully selected patients has similar in-hospital procedural success and major complications rates, as well as mid-term (18-month) clinical outcomes, as compared with single SVG stenting. Thus, multiple SVG interventions using stents may be a viable revascularization strategy for carefully selected patients and suitable lesions in multiple SVG disease.

In-hospital and long-term results of stent deployment compared with balloon angioplasty for treatment of narrowing at the saphenous vein graft distal anastomosis site

Disease at the distal anastomosis site of saphenous vein grafts (SVGs) has been successfully treated with balloon angioplasty, with a lower restenosis rate than at sites of the aortoostial or proximal portion of the SVG. The role of stents for these lesions has not been well defined. To compare the in-hospital and long-term outcome of patients who underwent treatment at this site by either balloon angioplasty or tubular stent implantation, we studied 182 consecutive patients who underwent balloon angioplasty and 77 patients who underwent stenting between January 1994 and August 1997. Baseline clinical characteristics for both groups were similar. Angiographically, SVG stenoses treated with stents were older, longer in lesion length, and more restenotic. The in-hospital outcome was similar for both groups, with 98% procedural success rates and 1% major ischemic complications. Long-term follow-up was obtained for 93% of the patients, for an average of 17 +/- 14 months. The mortality rates were similar for patients who underwent balloon angioplasty and stenting (11.6% vs 13%, p = NS). The Q-wave myocardial infarction rates were also similar (1% vs 0%, p = NS). There was a trend toward a higher rate of target lesion revascularization in the balloon angioplasty group (25% vs 14%, p = 0.058). We conclude that percutaneous revascularization of the SVG distal anastomosis site by either balloon angioplasty or stenting can be performed with a high rate of procedural success and favorable in-hospital and long-term outcomes. Stent deployment may further improve the long-term outcome of these patients by reducing the need for repeat revascularization.

Successful treatment of a saphenous vein graft perforation with an autologous vein-covered stent

A 52-year-old man with a history of prior coronary bypass surgery suffered recurrent angina and underwent percutaneous placement of a stent within the midportion of the saphenous vein graft to the marginal branch of the left circumflex coronary artery, which was complicated by a significant perforation. The perforation was successfully closed using an NIR stent covered with a segment of autologous antecubital vein. Subsequent surgical exploration confirmed successful closure of the perforation. Cathet. Cardiovasc. Intervent. 48:382-386, 1999.

Results of saphenous vein graft stent implantation: single center results from use of oversized balloon catheters

The results and complications of a single-center experience of stent implantation in old saphenous vein grafts (SVGs) need to be defined. The authors studied their initial consecutive 92 patients (125 stents, 1.4 stents/per patient) with a mean age of 67+/-9 years. The patients' mean saphenous vein graft (SVG) age was 10+/-4 years, and the mean left ventricular ejection fraction was 46%+/-15. Patient population included unstable angina (65%), stable angina (10%), myocardial infarction (21%), and silent ischemia (4%). The authors implanted 122 Palmaz-Schatz/biliary and three Gianturco-Roubin stents. They aimed at a balloon-artery ratio of 1.1/1.0. Procedural success, defined as stent deployment with <50% stenosis without death/Q-wave myocardial infarction/coronary artery bypass grafting (MI/CABG) was 95%. The mean luminal diameter (MLD) increased from 0.6+/-0.5 to 3.3+/-0.8 mm (p<0.001) and mean SVG stenosis diameter was decreased from 80%+/-14 to -10%+/-11 (p<0.001). Angiographic SVG lesions exhibited thrombus (17%), ulceration (38%), and plaque rupture (28%). Sixty-two patients were treated with warfarin and aspirin and 30 with ticlid and aspirin. Complications included death in three patients (3.3%) who sustained subacute stent thrombosis, and two of three had Q-wave MI. Distal embolization occurred in seven patients (8%); six of seven sustained a non Q-wave acute myocardial infarction (AMI); and one of seven a Q-wave MI. Eight (9%) patients had major groin hematoma, two had pseudoaneurysm (2.2%), one had arteriovenous (A-V) fistula (1.1%), two had vascular surgery (2.2%), nine had blood transfusion (9.8%), and three had stent migration (3.3%). Single-center experience with stents in SVGs indicates a highly successful procedural and angiographic immediate result. However, it was complicated by significant risk of non Q-wave MI due to distal coronary embolization which may affect prognosis.

Coronary microembolization--its role in acute coronary syndromes and interventions

The diagnosis coronary artery disease is classically based on patient's symptoms and morphology, as analyzed by angiography. The importance of risk factors for the development of coronary atherosclerosis and disturbance of coronary vasomotion is clearly established. However, microembolization of the coronary circulation has also to be taken into account. Microembolization may occur as a single or as multiple, repetitive events, and it may induce inflammatory responses. Spontaneous microembolization may occur, when the fibrous cap of an atheroma or fibroatheroma (Stary i.v. and Va) ruptures and the lipid pool with or without additional thrombus formation is washed out of the atheroma into the microcirculation. Such events with progressive thrombus formation are known as cyclic flow variations. Plaque rupture occurs more frequently than previously assumed, i.e. in 9% of patients without known heart disease suffering a traffic accident and in 22% of patients with hypertension and diabetes. Also, in patients dying from sudden death microembolization is frequently found. Patients with stable and unstable angina show not only signs of coronary plaque rupture and thrombus formation, but also microemboli and microinfarcts, the only difference between those with stable and unstable angina being the number of events. Appreciation of microembolization may help to better understand the pathogenesis of ischemic cardiomyopathy, diabetic cardiomyopathy and acute coronary syndromes, in particular in patients with normal coronary angiograms, but plaque rupture detected by intravascular ultrasound. Also, the benefit from glycoprotein IIb/IIIa receptor antagonist is better understood, when not only the prevention of thrombus formation in the epicardial atherosclerotic plaque, but also that of microemboli is taken into account. Microembolization also occurs during PTCA, inducing elevations of troponin T and I and elevations of the ST segment in the EKG. Elevated baseline coronary blood flow velocity, as a potential consequence of reactive hyperemia in myocardium surrounding areas of microembolization, is more frequent in patients with high frequency rotablation than in patients with stenting and in patients with PTCA. The hypothesis of iafrogenic microembolization during coronary interventions is now supported by the use of aspiration and filtration devices, where particles with a size of up to 700 microns have been retrieved. In the experiment, microembolization is characterized by perfusion-contraction mismatch, as the proportionate reduction of flow and function seen with an epicardial stenosis is lost and replaced by contractile dysfunction in the absence of reduced flow. The analysis of the coronary microcirculation, in addition to that of the morphology and function of epicardial coronary arteries, and in particular appreciation of the concept of microembolization will further improve the understanding of the pathophysiology and clinical symptoms of coronary artery disease.

Novel distal occluder washout method for prevention of no-reflow during stenting of saphenous vein grafts

This study assessed safety of the distal occlusion washout (DOW) method for prevention of no-reflow during stenting of degenerated saphenous vein grafts (SVGs). The DOW method involves protection of distal native coronary circulation with an occlusive balloon during the pretreatment and washout steps prior to stenting. Outcomes of stenting of 23 grafts in 21 patients after pretreatment with the DOW method were evaluated. The mean graft age was 7.4 +/- 4.3 years. The mean treated lesion length was 53 +/- 28 mm. Total occlusions were treated in 6 grafts and thrombotic lesions in 10 nontotally occluded grafts. One non-Q-wave MI and one acute stent thrombosis were observed. No deaths, Q-wave MIs, or subacute thromboses occurred. Follow-up in 18/21 (85.7%) patients at 28 +/- 8 weeks demonstrated target graft revascularization in 1 (5%) patient. The DOW method prevented clinically significant no-reflow in all 23 degenerated SVGs stented.

Retrieval and analysis of particulate debris after saphenous vein graft intervention

OBJECTIVES

This study was designed to evaluate the composition and quantity of particulate debris resulting from vein graft intervention.

BACKGROUND

Distal embolization and "no reflow" are frequent and important complications resulting from angioplasty of diseased saphenous vein grafts. Little is known about the composition and quantity of embolic particulate debris associated with vein graft intervention, and no intervention has been shown to protect against its clinical consequences.

METHODS

A catheter system, designed to contain, retrieve and protect against distal embolization of this material, was evaluated during 27 percutaneous interventional saphenous vein graft procedures. Clinical, angiographic and pathologic analyses were performed.

RESULTS

The duration of distal graft occlusion required to allow intervention and subsequent debris removal was 150 +/- 54 s, decreasing as experience was gained. Thrombolysis in Myocardial Infarction trial (TIMI) flow grade increased from 2.6 +/- 0.8 to 3.0 +/- 0.0. Creatine kinase (CK) rose above normal in three patients (11.1%) exceeding 3x normal in one (3.7%) resulting in the diagnosis of non-Q-myocardial infarction. Particulate material was identified following 21 of 23 procedures suitable for analysis. Particle size was 204 +/- 57 microm in the major axis and 83 +/- 22 microm in the minor axis. Particles consisted predominantly of soft acellular atheromatous material, such as that typically found under a fibrous cap. Semiquantitative analysis suggested that the quantity of particulate material was less following stenting than following balloon dilation.

CONCLUSIONS

Particulate matter is commonly present following routine angioplasty and stenting of saphenous vein grafts. Containment, retrieval and analysis of this particulate debris are all feasible. Comparison to prior clinical experience is limited by small sample size. However, to the extent that these particles may contribute to distal embolization, no-reflow and infarction, such a system may contribute to the reduction of complications following vein graft intervention.

Effects of a positron-emitting vanadium-48 nitinol stent on experimental restenosis in porcine coronary arteries: an injury-response study

BACKGROUND

The major limitation of coronary stenting is restenosis due to exaggerated neointimal thickening. We evaluated a positron-emitting V48 nitinol stent in a porcine coronary model of restenosis.

METHODS AND RESULTS

Pigs (n = 16) received a control nonradioactive and a V48 stent (1.5 or 10.6 muCi) randomized to the left anterior descending artery (LAD) and right coronary artery (RCA). Histology, morphometric variables, and strut injury scores were evaluated after 32 days. Peristrut fibrinoid deposits were greater in the high-dose group (p < 0.0001). Control stent area stenosis (AS) and mean neointimal thickness (NIT) correlated with injury (r = 0.81 and 0.79, respectively). Higher-dose stents reduced AS by 20% (0.57 +/- 0.13 vs. 0.71 +/- 0.16; p = 0.029) and mean NIT by 35% (0.44 +/- 0.16 vs. 0.71 +/- 0.24mm; p = 0.001) compared with controls. Lower-dose 1.5-muCi stents did not differ from controls. NIT over individual struts was reduced in the high-dose group compared with controls by 0.18 mm for grade 1 injury, 0.31 mm for grade 2, and 0.38 mm for grade 3 (p < 0.02 for all comparisons).

CONCLUSIONS

1.5-muCi V48 nitinol stents did not influence vessel histology or restenotic parameters in pig coronary arteries. In contrast, 10.6-muCi stents created a distinctive histological picture consisting of increased fibrinoid deposits on the neointimal-facing side of the struts without cellular organization. Higher dose radioactive stents significantly reduced AS and mean NIT. The reduction in neointimal thickening was greatest when the depth of strut penetration into the vascular wall was most severe.

An embolization containment device

A coaxial catheter system for containment of distal embolization is described. Utilizing a novel 0.014" hypotube with a distal elastomeric occlusion balloon, the PercuSurge GuardWire functions as a guidewire while trapping distal embolization resulting from more proximal intervention. The particulate debris is evacuated with a single operator exchange aspiration catheter (Export catheter) prior to deflation of the distal occlusion balloon. This animal study confirmed the feasibility of concept. The system was easily delivered through tortuous coronary anatomy. The GuardWire served as an adequate rail for delivery of dilatation balloons and a multitude of stents. There was no evidence of deep wall damage from low-pressure inflation and apposition of the distal occlusion balloon.

Interesting cases from the University of Texas Medical Branch

This article discusses the cases for four patients with unstable angina. The first case is an example of the "high-risk" patient with widespread ECG changes, heart failure, and enzymatic elevations during an episode of chest pain. The second patient illustrates an unusual cause of unstable angina in a young women. The third patient had a large thrombus visible on angiography and management strategies for dealing with intracoronary thrombus are discussed. The final patient had an extensive past cardiac history with two prior coronary artery bypass operations and we discuss the recent advances made in the treatment of degenerative vein graft disease.

Predictors of long-term outcome after stent implantation in a saphenous vein graft

Stenting of saphenous vein graft (SVG) lesions is associated with significant clinical events at late follow-up. We sought to determine predictors of clinical outcome after this procedure. One hundred twenty-eight balloon-expandable stents were implanted in the SVGs of 106 patients. Baseline clinical and angiographic characteristics were analyzed. All grafts, including those not stented, were scored for extent of disease involving the luminal surface of the graft, and for the presence of low profile lesions (< 50% graft stenosis) and/or high profile lesions (> or = 50% graft stenosis). The in-hospital success rate was 98.1%. Before discharge, no patient died, required bypass surgery, or had repeat angioplasty of the same graft. Follow-up was obtained on all the patients. At a median of 18 months, 15% had died, 17% had experienced myocardial infarction, 20% had required repeat bypass surgery, and 37% needed repeat angioplasty to either the same site or a different lesion. Event-free survival was recorded in only 44% of the patients. The cumulative Kaplan-Meier survival at 2.4 years was 78.7%. Using the Cox proportional hazards model, predictors of survival were the absence of a high profile lesion in any nonstented patent graft (p = 0.004), and the use of lipid-lowering agents at follow-up (p = 0.01). Stenting SVG lesions can be performed with a high degree of procedural success, but at long-term follow-up there is a high rate of cardiac events. The absence of a high profile lesion in any nonstented patent graft is the strongest predictor of survival.

Use of stents to treat kinks causing obstruction in a left internal mammary artery graft

Left internal mammary arteries (LIMA) are used routinely as grafts to the left anterior descending coronary artery (LAD) in selected patients undergoing coronary artery bypass graft (CABG) surgery because of better long-term patency rates. Pathology other than fibrointimal hyperplasia, accelerated atherosclerosis, or thrombus can sometimes cause obstructive lesions in such grafts. This report illustrates a kink in a LIMA graft to the LAD causing an obstructive lesion shortly after surgery and describes the subsequent management of this lesion with intracoronary stents.

Percutaneous transluminal therapy of occluded saphenous vein grafts: can the challenge be met with ultrasound thrombolysis?

BACKGROUND

Percutaneous transluminal treatment of a thrombotic vein graft yields poor results. We have previously reported our experience with transluminal percutaneous coronary ultrasound thrombolysis (CUT) in the setting of acute myocardial infarction (AMI). This report describes the first experience with ultrasound thrombolysis in thrombus-rich lesions in saphenous vein grafts (SVGs), most of which were occluded.

METHODS AND RESULTS

The patients (n=20) were mostly male (85%), aged 64+/-4 years old. The presenting symptom was AMI in 2 patients (10%) and unstable angina in the rest. Fifteen patients (75%) had totally occluded SVGs. The median age of clots was 6 days (range, 0 to 100 days). The ultrasound thrombolysis device has a 1.6-mm-long tip and fits into a 7F guiding catheter over a 0.014-in guidewire in a "rapid-exchange" system. CUT (41 kHz, 18 W, </=6 minutes) led to device success in 14 (70%) of the patients and residual stenosis of 65+/-28%. Procedural success was obtained in 13 (65%) of the patients, with a final residual stenosis of 5+/-8%. There was a low rate of device-related adverse events: 1 patient (5%) had a non-Q-wave myocardial infarction, and distal embolization was noted in 1 patient (5%). Adjunct PTCA or stenting was used in all patients. There were no serious adverse events during hospitalization.

CONCLUSIONS

Ultrasound thrombolysis in thrombus-rich lesions in SVGs offers a very promising therapeutic option.