Comparative results of transluminal extraction coronary atherectomy in saphenous vein graft lesions with and without thrombus

Outcome of undersized drug-eluting stents for percutaneous coronary intervention of saphenous vein graft lesions

We sought to determine the outcome with undersized drug-eluting stents for percutaneous coronary intervention of saphenous vein graft lesions. Using intravascular ultrasound guidance, 209 saphenous vein graft lesions were treated with drug-eluting stents (153 sirolimus-eluting and 56 paclitaxel-eluting stents). The lesions were divided into 3 groups according to the ratio of the stent diameter to the average intravascular ultrasound reference lumen diameter: group I, <0.89; group II, 0.9 to 1.0; and group III, >1.0. Angiographic no-reflow was defined as a Thrombolysis In Myocardial Infarction flow grade of 0, 1, and 2 after percutaneous coronary intervention. Plaque intrusion was defined as tissue extrusion through the stent struts. Stent malapposition was defined as one or more stent struts that had clearly separated from the vessel wall with evidence of blood speckles behind the strut. No significant differences were found in the use of distal protection devices (group I, 44%; group II, 35%; and group III, 36%; p = 0.5); and no significant differences were found in the incidence of stent malapposition among the 3 groups (group I, 21%; group II, 42%; and group III, 52%; p = 0.001). The plaque intrusion area (group I, 0.13 +/- 0.30 mm(2); group II, 0.25 +/- 0.42 mm(2); and group III, 0.31 +/- 0.40 mm(2); p = 0.018) and plaque intrusion volume (group I, 0.25 +/- 0.68 mm(3); group II, 0.40 +/- 0.68 mm(3); and group III, 0.75 +/- 1.34 mm(3); p = 0.007) were smallest in group I. The plaque intrusion area and plaque intrusion volume correlated with the ratio of the stent diameter to the average intravascular ultrasound reference lumen diameter (r = 0.278, p <0.001 and r = 0.283, p <0.001, respectively). The incidence of a creatine kinase-MB elevation >3 times normal was 6% in group I, 9% in group II, and 19% in group III (p = 0.025). No significant differences were found in the incidence of 1-year target lesion revascularization (group I, 13%; group II, 9%; and group III, 15%; p = 0.5) or target vessel revascularization (group I, 13%; group II, 13%; and group III, 15%; p = 0.9) among the 3 groups. In conclusion, the use of undersized drug-eluting stents to treat patients with saphenous vein graft lesions is associated with a reduction in the frequency of post-percutaneous coronary intervention creatine kinase-MB elevation without an increase in 1-year events.

Role of thrombectomy in acute myocardial infarction

Acute ST elevation myocardial infarction results from atherosclerotic plaque rupture with subsequent thrombus formation, leading to complete or near complete occlusion of an epicardial coronary artery. Minimization of the mechanical obstruction from this thrombus remains the main goal of therapy in ST elevation myocardial infarction. Primary percutaneous coronary intervention for an ST elevation myocardial infarction appears to be the preferred mode of revascularization over thrombolytic therapy if the door-to-balloon time target of 90 min is achievable. The idea of reducing the thrombus burden with the use of devices as an adjunct to percutaneous coronary intervention is an attractive one. Several thrombectomy devices have been studied in randomized clinical trials, but no definitive conclusions have emerged, owing to conflicting results and variable clinical end points. This article intends to shed further light on the potential role of thrombectomy in the treatment of acute myocardial infarction.

Rheolytic Thrombectomy during Percutaneous Coronary Intervention Improves Long-Term Outcome in High-Risk Patients with Acute Myocardial Infarction

OBJECTIVES

Aim of the present study was to compare the immediate and long-term effects of AngioJet rheolytic thrombectomy performed in the setting of a percutaneous coronary angioplasty (PTCA) with those of conventional PTCA in patients with acute myocardial infarction (AMI) and angiographic evidence of high intracoronary thrombus burden.

BACKGROUND

Plaque rupture, with subsequent exposure to the flowing bloodstream of high thrombotic materials often leads to intravascular thrombosis, representing the main pathophysiological event of acute coronary syndromes. PTCA is the first-choice treatment for these patients in hospitals with cardiac catheterization facilities. However, distal embolization of thrombotic material, fibrin, and other fragments from atherosclerotic plaques might lead to procedural failure.

METHODS

Immediate and 1-year follow-up results of a group of 30 consecutive patients, presenting with AMI and angiographic evidence of high thrombus burden, who underwent rheolytic thrombectomy and PTCA were compared with those of 30 consecutive patients with similar clinical presentation, risk profile, and angiographic picture, and treated with standard PTCA procedure.

RESULTS

After the procedure, angiographic analysis showed a higher incidence of final thrombolysis in myocardial infarction (TIMI) flow grade 3 in the AngioJet group (93.3% vs 83.3%, P = 0.034). In addition, mean corrected TIMI frame count (cTFC) was significantly lower in the AngioJet group (22.4 vs 32.4, P = 0,0004). At 1-year follow-up, patients treated with AngioJet showed a significantly lower incidence of death (3.33% vs 13.33%,P < 0.001), major adverse cardiac events (MACE: 10% vs 30%, P = 0.026), and need of revascularization (6.67% vs 20%, P = 0.013).

CONCLUSIONS

Data of the present study highlight that AngioJet thrombectomy in selected AMI patients at high risk for distal thrombotic embolization results not only in immediately improved angiographic results as compared to conventional PTCA but, indeed, seems to be associated with a significantly better long-term clinical outcome.

Mechanical protection of cardiac microcirculation during percutaneous coronary intervention of saphenous vein grafts

Saphenous vein bypass grafts permeability is one of the most important limitations of open heart surgery. The risks associated with surgical re-intervention are greater than those associated with the initial procedure. While native coronary arteries usually have fixed, fibrotic or calcified atherosclerotic plaques, the disease in the vein grafts contains soft material. When this material is compressed during percutaneous angioplasty, there is an unfavorable immediate outcome due to distal embolization of thrombus and plaque debris. In addition, the risk of post-procedure adverse events are higher when the grafts have a long time of implantation, due to a greater risk of branch occlusion or no-reflow at the adjacent microcirculation. The clinical consequence is a Non-Q-Wave Myocardial Infarction that is reflected in the increased serum cardiac enzymes. It is because of this complication that the distal protection devices were developed. The purpose of this paper is to review and discuss the current data on the distal protection devices available now for the treatment of degenerative saphenous vein graft disease. Currently, there are two distal protection devices approved in the United States: the Guardwire Balloon and Aspiration (Export) System and the Filter Wire EX. Other devices like the Triactiv System, Angioguard XP/ECW, DOW, MedNova Cardioshield, Medtronic-AVE DPD and the E-Trap Filter are still being studied. The first observational studies showed the safety and efficacy of the approved devices. A large randomized trial initially confirmed a significant decrease of in-hospital and 30-day cardiac adverse events, mainly Non-Q-Wave Myocardial Infarction, when angioplasty was performed with the assistance of the Guardwire System. Subsequently, another randomized study showed an equivalence between the Guardwire System and the Filter Wire EX. Distal protection devices have an acceptable performance, however, further technological improvements are warranted for a quick preparation, delivery and/or retrieval of these devices.

Cost-effectiveness of distal embolic protection for patients undergoing percutaneous intervention of saphenous vein bypass grafts: results from the SAFER trial

OBJECTIVES

The goal of this research was to determine the incremental cost and cost-effectiveness of embolic protection in patients undergoing percutaneous revascularization (PCI) of diseased saphenous vein bypass grafts (SVGs).

BACKGROUND

Distal protection using the GuardWire balloon occlusion device has been shown to reduce major ischemic complications in patients undergoing SVG PCI, but the cost-effectiveness of this approach is unknown.

METHODS

We prospectively measured medical resource utilization and cost for 801 patients undergoing SVG intervention who were randomized to distal protection using the GuardWire (n = 406) or conventional treatment (n = 395) in the Saphenous Vein Graft Angioplasty Free of Emboli Randomized (SAFER) trial. Long-term survival and cost-effectiveness were projected based on observed 30-day outcomes and a validated survival model for postcoronary artery bypass graft patients.

RESULTS

Compared with conventional treatment, distal protection increased initial procedural costs by approximately $1,600 ($6,326 vs. $4,779, p < 0.001). However, by reducing ischemic complications, distal protection reduced mean length of stay by 0.4 days and other hospital costs by nearly $1,000 ($6,846 vs. $7,811, p = 0.018). As a result, overall initial hospital costs were only $582 per patient higher with distal protection. Based on the observed 30-day cost and outcome differences in the trial, the incremental cost-effectiveness ratio for distal protection was $3,718 per year of life saved and remained <$40,000 per year of life saved in 97.3% of bootstrap simulations (95% confidence interval, $0 to $43,079).

CONCLUSIONS

For patients undergoing PCI of diseased SVGs, distal protection using the GuardWire system is an attractive use of limited health care resources.

Relation of final lumen dimensions in saphenous vein grafts after stent implantation to outcome

Larger final lumen dimensions after percutaneous coronary interventions in native coronary arteries lead to lower restenosis rates. We sought to determine the impact of stent expansion, as assessed by intravascular ultrasound, on clinical results of stent implantation in saphenous vein grafts (SVGs). We identified 226 consecutive patients who underwent intravascular ultrasound-guided stenting of 234 de novo SVG lesions. Patients were divided into 2 groups based on the final stent cross-sectional area (CSA): group I (stent CSA <100% of the reference lumen CSA, n = 176 patients, 182 lesions) and group II (stent CSA >/=100% of the reference lumen CSA, n = 50 patients, 52 lesions). Baseline patient characteristics were similar between the 2 groups with the exception of smaller lesions in group II. More aggressive stent expansion (group II) was associated with (1) increased rates of in-hospital non-Q-wave myocardial infarction (29% vs 17%, p = 0.05), (2) any myocardial infarction (26% vs 8%, p = 0.003) at 1-year follow-up, and (3) no improvement in target vessel revascularization at 1 year (31% vs 26%, p = 0.3). Aggressive stent expansion in SVG lesions resulted in higher myocardial infarction rates and, unlike native arteries, no improvement in target vessel revascularization rate at 1 year. A less aggressive stent implantation strategy in SVGs than in native coronary lesions appears prudent.

Safety and efficacy of a novel device for treatment of thrombotic and atherosclerotic lesions in native coronary arteries and saphenous vein grafts: results from the multicenter X-Sizer for treatment of thrombus and atherosclerosis in coronary applications trial (X-TRACT) study

Intervention in thrombotic lesions and diseased saphenous vein grafts frequently results in thromboembolic complications, including no-reflow, distal branch occlusion, periprocedural MI, and death. The utility of a novel thromboatherectomy device, the X-Sizer, was tested in 50 consecutive patients at nine U.S. centers. A total of 61 lesions were treated in 31 vein grafts and 19 native coronary arteries; thrombus was present in 78% of lesions, and TIMI 0-1 flow in 21%. TIMI 3 flow improved from 57% at baseline to 94% postprocedure. No patient developed visible distal thromboemboli, side-branch occlusion, or reduced antegrade flow. Thirty-day events included one death (2.0%), Q- or non-Q-wave MI in 4.0%, TVR in 6.0%, and any MACE in 6.0%. We conclude that the use of the X-Sizer prior to percutaneous intervention is safe in high-risk vein grafts and thrombotic lesions and results in a low rate of adverse events compared to historical controls.

Distal occluder and rheolytic thrombectomy of a saphenous vein graft lesion with a large associated thrombus

Percutaneous intervention in thrombus-containing lesions is frequently associated with complications, including distal embolization and no-reflow. In saphenous vein bypass grafts (SVG), friable atheroma and associated thrombus make interventions particularly difficult. Distal protection strategies are in development, but complete protection with removal of all potentially embolic material is challenging. This case illustrates a novel technique using a distal occluder balloon and rheolytic thrombectomy followed by stent deployment to treat a SVG lesion. This combination therapy was technically feasible, resulted in no angiographic complications and normal creatine kinase levels throughout follow-up, and can be used during high risk SVG interventions.

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

Angiographic outcome after intracoronary X-Sizer helical atherectomy and thrombectomy: first use in humans

The objective of this study was to evaluate the early angiographic outcome in the first human subjects who underwent intracoronary atherectomy and thrombectomy using the X-Sizer helical cutting and aspiration system. Percutaneous coronary interventions in patients with thrombo-occlusive disease or friable degenerative saphenous vein grafts are associated with considerable periprocedural morbidity and mortality, predominantly related to microscopic distal embolization. X-Sizer catheter system is a novel atherectomy and thrombectomy device that consists of a helix cutter connected to a handheld motor drive unit and a vacuum collection chamber for aspiration of excised atheroma, thrombus, and debris. Quantitative coronary angiography was obtained in 14 patients before and after X-Sizer extraction atherectomy with adjunctive balloon angioplasty and stenting. Thirteen native coronary arteries and one saphenous vein graft were treated. Mean preprocedural reference vessel diameter was 3.06 +/- 0.66 mm. There were 71.4% AHA/ACC type B2 and C lesions. Preprocedural thrombus was present in nine patients and total occlusion in 64% of cases. Minimal luminal diameter was increased from 0.29 +/- 0.47 mm to 1.32 +/- 0.64 mm, a gain of 1.04 +/- 0.69 mm after atherectomy. Final total gain was 1.47 +/- 0.61 mm. Mean diameter stenosis was reduced from 89.3% to a final residual stenosis of 14.4%. Postatherectomy distal embolization occurred in one patient who had heavy preprocedural thrombus burden. No episodes of perforation, distal coronary spasm, abrupt closure, or slow/no-reflow occurred. The angiographic analysis of the first cohort of human subjects suggests that X-Sizer helical atherectomy is a feasible method of removing occlusive tissue or thrombus in coronary artery disease with a low angiographic complication rate. A large-scale randomized phase II clinical trial is underway to determine the ultimate safety and efficacy of this device in thrombo-occlusive native coronary arteries and saphenous vein grafts.

Percutaneous intervention of old degenerated saphenous vein grafts

The treatment of failing bypass grafts is difficult because repeat surgery carries a higher mortality rate than a first operation. Percutaneous intervention is more difficult because mechanical manipulation of these soft, friable atherosclerotic plaques have been associated with a significant rate of distal embolization, myocardial infarction, late restenosis and death. Balloon angioplasty alone has proven to have serious limitations in the treatment of older degenerated saphenous vein grafts (SVG). Although directional atherectomy yielded a higher angiographic success in a randomized trial, the restenosis rate was similar, and the procedural complications higher. The transluminal extraction catheter (TEC) has also shown significant limitations for the treatment of degenerated or thrombotic vein grafts with a significant procedural complication rate. A randomized trial comparing stenting versus balloon angioplasty in focal SVG lesions showed a higher freedom from major adverse cardiovascular events in the stent group, but there was no significant difference in the angiographic restenosis rates. More recently, rheolytic thrombectomy and mechanical thrombolysis have proven useful in treating thrombotic lesions in SVG. In addition, the recent development of distal protection devices appears very promising and will probably contribute to decreased distal embolization during percutaneous revascularization of these conduits.

Economic assessment of rheolytic thrombectomy versus intracoronary urokinase for treatment of extensive intracoronary thrombus: Results from a randomized clinical trial

BACKGROUND

Despite advances in mechanical and pharmacologic therapy, thrombus-containing lesions are at high risk for adverse events and remain a challenging subset for percutaneous coronary revascularization. Recently, rheolytic thrombectomy with the AngioJet device has been shown to safely remove intracoronary thrombus, but the overall cost-effectiveness of this technique is unknown.

METHODS

We determined in-hospital and 1-year follow-up costs for 349 patients with overt intracoronary thrombus who were randomly assigned to treatment with intracoronary urokinase (6- to 30-hour infusion followed by definitive revascularization; n = 169) or immediate thrombectomy with the AngioJet device (n = 180) as part of the Vein Graft AngioJet Study (VeGAS) 2 trial. Catheterization laboratory costs were based on measured resource utilization and 1998 unit costs, whereas all other costs were estimated from hospital charges and cost center-specific cost-to-charge ratios.

RESULTS

Compared with urokinase, rheolytic thrombectomy reduced the incidence of periprocedural myocardial infarction (12.8% vs 30.3%, P <.001) and major hemorrhagic complications (2.8% vs 11.2%, P <.001) and shortened length of stay by nearly 1 day (4.2 vs 4.9 days; P =.02). As a result, AngioJet treatment reduced procedural costs, hospital room/nursing costs, and ancillary costs with resulting hospital cost savings of approximately $3500 per patient during the initial hospitalization ($15,311 vs $18,841, P <.001). These cost savings were maintained at 1 year of follow-up ($24,389 vs $29,109, P <.001).

CONCLUSIONS

Compared with standard treatment with intracoronary urokinase, rheolytic thrombectomy both improves clinical outcomes and reduces overall medical care costs for patients with extensive intracoronary thrombus.

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.

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.

Acute thrombotic-ischemic coronary syndromes: the usefulness of TEC

Transluminal extraction catheter (TEC) is a percutaneous device that performs simultaneous thrombus aspiration and plaque excision. Clinical indications for its application are acute myocardial infarction, unstable angina, and stable angina caused by atherosclerotic, thrombotic lesions located within native coronary arteries and degenerated saphenous vein grafts. The device is useful in management of ischemic patients with contraindications to either pharmacologic thrombolytics or platelet GPIIb/IIIa receptor inhibitors, and can also effectively be used in combination with these agents. A successful TEC procedure requires careful patient selection, strict adherence to recommended indications, optimal equipment selection, familiarity with mechanical components of the device, full understanding of safe and efficacious techniques for deployment and activation, as well as recognition of unique associated angiographic manifestations such as the "empty-pouch phenomenon." As with other debulking devices, the incidence of restenosis post-TEC appears to be directly related to acute luminal gain at the time of procedure and therefore requires the need for adjunct stenting. This communication describes and illustrates various clinical, technical, and angiographic aspects of TEC procedure in patients with acute ischemic-thrombotic coronary syndromes. Cathet. Cardiovasc. Intervent. 48:406-420, 1999.

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.

Risk of distal embolization and infarction with transluminal extraction atherectomy in saphenous vein grafts and native coronary arteries. NACI Investigators. New Approaches to Coronary Interventions

Lower success rates have been reported when treating high-risk lesions in saphenous vein grafts (SVGs) and native coronary arteries with balloon angioplasty. The transluminal extraction atherectomy catheter (TEC) has been proposed to reduce the incidence of distal embolization (DE) in subsets of high-risk lesions. To define the utility of TEC in reducing the incidence of DE, all patients who were enrolled in the New Approaches to Coronary Interventions (NACI) Registry and had TEC planned as the sole treatment were studied (329 patients with 381 lesions). Of the lesions treated, 75.9% were in SVGs; 37.5% were thrombotic; and 15% were total occlusions. Adjunctive percutaneous transluminal coronary angioplasty (PTCA) was performed in 87.4% of lesions. Multivariate predictors of DE were: noncardiac disease, stand alone TEC, thrombus, and larger vessel size. DE was associated with an 18.5% in-hospital mortality vs. 3.0% without DE (P < 0.01) and a 25.9% MI rate vs. 5.0% without DE (P < 0.01). In conclusion, in this high-risk subset of patients, TEC is associated with an 8.3% incidence of DE with thrombotic and SVGs lesions. DE associated with TEC appears to carry high morbidity and mortality. Additional techniques to control DE are needed to reduce the frequency of complications in these patients.

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.

Rheolytic thrombectomy of chronic coronary occlusion

Percutaneous intervention in patients with intracoronary thrombus continues to pose a significant clinical challenge. In this report, we describe the successful treatment of a 44-year-old patient with an extensive chronic thrombotic occlusion of the right coronary artery using a rheolytic thrombectomy catheter. Despite angiographic documentation of coronary thrombosis 104 days prior to treatment and a voluminous thrombus burden (60 mm in length x 3 mm in diameter), rapid recanalization was accomplished with this device without embolic complications. At 1 year clinical follow-up, the patient has remained symptom free. The design of this novel device and its mechanism of action are described.

Treatment of thrombus containing lesions in diseased native coronary arteries and saphenous vein bypass grafts using the AngioJet Rapid Thrombectomy System

The occurrence of fresh thrombus during percutaneous coronary interventions, especially in patients with diffusely diseased saphenous vein bypass grafts is associated with an increased incidence of procedural complications and clinical events. The AngioJet Rapid Thrombectomy Catheter was designed to remove thrombus via a Bernoulli effect induced vacuum. Here we report on the technical aspects of the device and the AngioJet thrombectomy procedure. Indications and potential complications, both procedure- and device related are discussed.

Predictors of acute and long-term outcome with transluminal extraction atherectomy: the New Approaches to Coronary Intervention (NACI) registry

The New Approaches to Coronary Intervention (NACI) registry was established to define the role of new coronary devices in overcoming the limitations of balloon angioplasty. The purpose of the present study was to evaluate the acute and long-term efficacy of the transluminal extraction catheter (TEC) device utilizing data from the NACI registry and identify clinical and anatomic patient subsets who may benefit from this device. From 1990-1994, >4,300 patients from 39 clinical sites enrolled consecutive patients treated with one of the 7 new devices to the NACI registry. The study population consists of 331 patients (385 lesions) treated with planned TEC as the sole new device. Of these patients, 243 (292 lesions) were treated for saphenous vein graft (SVG) disease and 88 (93 lesions) for native disease. Patients undergoing SVG treatment were older and more likely to be male. They had lower ventricular function, more unstable angina, and a higher incidence of congestive heart failure. Multivessel disease was more prevalent in the SVG cohort, as was evidence of thrombus before treatment. Although device success was achieved in 50% of SVG lesions and 41% of native lesions, lesion success was achieved in 90% and 78%, respectively, after adjunctive balloon angioplasty, and procedure success rates were 86% and 79%, respectively. The in-hospital major complication (death/Q-wave myocardial infarction/emergency coronary artery bypass graft [CABG] surgery) rate was higher in the SVG cohort (6.2% vs 2.3%), mainly due to higher mortality rate (5.3% vs 1.1%). Multivariate analysis showed that SVG was not an independent predictor for either an in-hospital major complication or clinical failure. The risk factors for major in-hospital complications were history of congestive heart failure (odds ratio = 3.17) and thrombus (odds ratio = 3.36). For clinical failure the risk factors were diabetes (odds ratio = 1.88), thrombus (odds ratio = 2.08), and calcium (odds ratio = 3.09). One-year rates of death, Q-wave myocardial infarction, or any repeat revascularization were 51% in the SVG cohort and 41% in the native cohort. Following adjustment, patients treated for SVG disease did not have a higher risk when compared with those treated for native disease. The factors significantly associated with this composite event at 1 year are male (relative risk = 1.41), patients with history of congestive heart failure (relative risk = 1.56), and total occlusions (relative risk = 1.52). This study shows that for both SVG and native cohorts, device success rates were low with TEC alone, but acceptable lesion success rates were achieved when adjunctive PTCA was used. In-hospital as well as 1-year major complications were higher in the SVG cohort. However, after adjusting for other risk factors, SVG attempt was not significantly associated with either in-hospital or 1-year events.

Improving the results of coronary angioplasty

Coronary angioplasty has changed dramatically in the past three years with major reductions in suboptimal results and restenosis rates, and improvements in safety, efficacy and cost-effectiveness. Intracoronary stent implantation with optimisation of strut expansion and the abandonment of anticoagulants after deployment, have led to less entry-site complications, facilitated early hospital discharge, virtually abolished subacute stent thrombosis and resulted in a 50% reduction in target vessel revascularisation. Adjuvant medical treatment with anti-platelet agents, including glycoprotein IIb/IIIa receptor inhibitors, improves the safety of angioplasty and may further reduce the restenosis rate. Selective use of debulking devices has extended the indications for angioplasty. High resolution fluoroscopy, quantitative coronary angiography and intracoronary ultrasound leading to improved diagnosis, equipment selection and treatment have contributed to better outcomes. Further clinical trials will compare angioplasty and stent implantation with coronary bypass surgery in patients with multivessel coronary disease, and may extend the indications for percutaneous transluminal coronary angioplasty (PTCA) to selected patients with three vessel disease.

A new thrombosuction catheter for coronary use: initial results with clinical and angiographic follow-up in seven patients

The presence of thrombus in a coronary vessel during percutaneous revascularisation can prevent adequate restoration of flow; it is also associated with an increased risk of distal embolization. We report the acute results and longer-term outcome of seven patients who underwent treatment with a new hydrodynamic thrombectomy catheter (Hydrolyser), designed for the rapid removal of acute, non-organised thrombus from coronary vessels. Three patients demonstrated total thrombotic occlusion of a coronary saphenous vein bypass graft (SVBG), whereas in four patients thrombus was present in a native coronary artery (NCA). In all seven patients, Hydrolyser thrombectomy resulted in removal of thrombus and restoration of flow through the occluded segment. Adjunctive balloon angioplasty or stent placement to treat residual stenosis was performed in five of the patients. Distal embolization of a free-floating thrombus mass occurred in one patient, without clinical sequelae. There were no procedure-related complications in any of the patients. One patient with a degenerated SVBG reoccluded after five days. The other six patients underwent angiographic follow-up after an interval of 3 to 8 months: A wide patent coronary artery, without restenosis, was seen in three of these patients, and the other three patients (two with treatment of an SVBG) underwent re-PTCA for restenosis. These data suggest that the Hydrolyser procedure, as reported in our experience, is safe and effective for the removal of acute thrombus in selected patients.

Influence of procedural success on immediate and long-term clinical outcome of patients undergoing percutaneous revascularization of occluded coronary artery bypass vein grafts

OBJECTIVES

This study sought to determine whether successful recanalization of an occluded vein graft is associated with improvement in long-term clinical outcome.

BACKGROUND

Coronary angioplasty of occluded vein grafts is associated with a lower initial success rate and a higher complication rate than angioplasty of vein grafts with subtotal stenoses and native coronary arteries. Whether successful angioplasty improves clinical outcome is unknown.

METHODS

We analyzed 77 consecutive patients who underwent angioplasty of an occluded saphenous vein coronary artery bypass graft between August 1983 and June 1994. Patients with a myocardial infarction in the previous 24 h were excluded from the study.

RESULTS

The mean age of the study cohort was 65 years; the mean (+/- SD) age of the treated grafts was 7.5 +/- 3.9 years. As an adjunct to balloon angioplasty, stents were used in 9% of procedures, laser in 30%, and atherectomy in 16%, and thrombolytic therapy was administered in 23% of patients. The angioplasty success rate was 71%. Major complications within 30 days of the procedure included death in 5.2% of patients, Q wave myocardial infarction in 1.3% and repeat bypass surgery in 7.8%; these events occurred with similar frequency in patients in whom angiographic success was and was not achieved. Kaplan-meier analysis comparing patients in whom angioplasty was successful (n = 55) and not successful (n = 22) revealed no differences in survival or occurrence of myocardial infarction or recurrent severe angina between the two groups in the 3 years after the procedure. Univariate analysis identified the age of the graft and use of newer interventional devices as predictors of death or myocardial infarction during this time period; procedural success was not associated with freedom from these adverse events after adjusting for these variables.

CONCLUSIONS

Angioplasty of occluded vein grafts is associated with a low initial success rate and a high complication rate. Successful angioplasty does not appear to reduce the occurrence of adverse events in the 3 years after the procedure.

Prospective study of extraction atherectomy in patients with acute myocardial infarction

Although percutaneous transluminal coronary angioplasty (PTCA) has been an effective treatment for primary reperfusion in acute myocardial infarction, patients with thrombolytic ineligibility, thrombolytic failure, cardiogenic shock, and vein graft occlusion remain at high risk for complications with PTCA treatment. The transluminal extraction catheter may be useful for treatment for such patients owing to its ability to aspirate thrombus. At 2 clinical centers, extraction atherectomy was prospectively evaluated in 100 patients (age 62 +/- 10 years). High-risk features included thrombolytic failure in 40%, postinfarct angina in 28%, presence of angiographic thrombus in 66%, presence of cardiogenic shock in 11%, and a saphenous vein graft occlusion in 29%. Procedural success, defined as a final residual stenosis <50% and Thrombolysis in Myocardial Infarction 2 or 3 grade flow, was seen in 94%. Events during the hospitalization included death in 5%, bypass surgery in 4%, and blood transfusion in 18%. In a substudy, patients enrolled at William Beaumont Hospital (n = 65) underwent elective predischarge angiography, which revealed a patent infarct-related vessel in 95%. These patients were also followed for 6 months with angiographic follow-up in 60%. Target vessel revascularization was necessary in 38%, and 6-month mortality was 10%. Although long-term vessel patency was 90%, angiographic restenosis occurred in 68%. Acute myocardial infarction patients can be treated with extraction atherectomy with a high technical success rate and a low incidence of complication. Infarct artery patency at 1 week and 6 months was excellent; however, angiographic restenosis remains a problem. Extraction of thrombus in this high-risk group of patients is associated with low in-hospital mortality and a high rate of vessel patency at 6 months.

Efficacy of angioscopy in determining the effectiveness of intracoronary urokinase and TEC atherectomy thrombus removal from an occluded saphenous vein graft prior to stent implantation

Percutaneous revascularization of thrombus containing saphenous vein grafts is associated with a high incidence of acute complications. This case report describes successful revascularization of an occluded vein graft employing angioscopically guided sequential urokinase infusion, TEC atherectomy and stent implantation.

Detailed clinical and angiographic analysis of transluminal extraction coronary atherectomy for complex lesions in native coronary arteries

OBJECTIVES

The purpose of this study was to describe the results of transluminal extraction coronary atherectomy in native coronary arteries.

BACKGROUND

Transluminal extraction coronary atherectomy was approved by the Food and Drug Administration for use in native coronary arteries and vein grafts.

METHODS

Between December 1988 and July 1992, transluminal extraction coronary atherectomy was performed in 181 native coronary arteries in 175 patients. A detailed angiographic and clinical assessment was performed.

RESULTS

Quantitative angiography (mean +/- SD) revealed an increase in minimal lumen diameter from 1.0 +/- 0.6 mm before to 1.3 +/- 0.7 mm after atherectomy, to 2.1 +/- 0.8 mm after final treatment (p < 0.001), corresponding to a diameter stenosis of 70 +/- 16%, 61 +/- 21% and 36 +/- 21%, respectively (p < 0.001). Final procedural success (final diameter stenosis < 50%, no major complications) was achieved in 84%. Adjunctive angioplasty was used after atherectomy in 152 lesions (84%) to further enlarge lumen dimensions (130 lesions, 72%), salvage technical failures (2 lesions, 1%) and reverse atherectomy-induced abrupt closures (20 lesions, 11%). Clinical complications included death (2.3%), Q wave myocardial infarction (3.4%) and emergency bypass surgery (2.8%). The strongest independent correlate of major clinical complications was development of abrupt closure immediately after atherectomy (p = 0.01). Clinical follow-up of 92% of eligible patients revealed clinical restenosis (repeat intervention, late bypass surgery, myocardial infarction or death) in 28.5%. Angiographic follow-up of 83% of eligible lesions revealed a restenosis rate (diameter stenosis > 50%) of 61%.

CONCLUSIONS

Transluminal extraction coronary atherectomy is limited by a modest degree of lumen enlargement, frequent need for adjunctive angioplasty and a high restenosis rate. For complex lesions in native coronary arteries, transluminal extraction coronary atherectomy appears to offer no advantage over conventional balloon angioplasty.