Predictors of outcome of percutaneous excimer laser coronary angioplasty of saphenous vein bypass graft lesions. The Percutaneous Excimer Laser Coronary Angioplasty Registry

A novel approach to saline/contrast delivery in excimer laser coronary atherectomy (ELCA) to enhance efficacy: MAXCon ELCA technique

The advent of excimer laser coronary atherectomy (ELCA) nearly four decades ago heralded a novel way to treat complex lesions, both coronary and peripheral, which were previously untraversable and thus untreatable. These complex lesions include heavily calcified lesions, ostial lesions, bifurcation lesions, chronic total occlusions, in-stent restenosis (including stent underexpansion), and degenerative saphenous vein grafts. We discuss the technology of ELCA, its indications, applications, and complications, and suggest the "MAXCon ELCA" technique for better outcomes without increased risk. Lastly, we present a case of MAXCon ELCA effectively treating a complex lesion.

SCAI Expert Consensus Statement on the Management of Calcified Coronary Lesions

The prevalence of calcification in obstructive coronary artery disease is on the rise. Percutaneous coronary intervention of these calcified lesions is associated with increased short-term and long-term risks. To optimize percutaneous coronary intervention results, there is an expanding array of treatment modalities geared toward calcium modification prior to stent implantation. The Society for Cardiovascular Angiography and Interventions, herein, puts forth an expert consensus document regarding methods to identify types of calcified coronary lesions, a central algorithm to help guide use of the various calcium modification strategies, tips for when using each treatment modality, and a look at future studies and trials for treating this challenging lesion subset.

Excimer laser technology in percutaneous coronary interventions: Cardiovascular laser society's position paper

Excimer Laser Coronary Atherectomy (ELCA) is a well-established therapy that emerged for the treatment of peripheral vascular atherosclerosis in the late 1980s, at a time when catheters and materials were rudimentary and associated with the most serious complications. Refinements in catheter technology and the introduction of improved laser techniques have led to their effective use for the treatment of a wide spectrum of complex coronary lesions, such as thrombotic lesions, severe calcific lesions, non-crossable or non-expandable lesions, chronic occlusions, and stent under-expansion. The gradual introduction of high-energy strategies combined with the contrast infusion technique has enabled us to treat an increasing number of complex cases with a low rate of periprocedural complications. Currently, the use of the ELCA has also been demonstrated to be effective in acute coronary syndrome (ACS), especially in the context of large thrombotic lesions.

Excimer Laser Atherectomy in Percutaneous Coronary Intervention: A Contemporary Review

Excimer laser coronary atherectomy (ELCA) during percutaneous coronary intervention (PCI) has been in use for more than twenty years. While early experiences were not favorable over balloon angioplasty alone, with improvement in operator technique, patient selection and technology, ELCA has established its own niche in contemporary PCI as a safe and effective atherectomy strategy. With growing experience in complex coronary interventions worldwide, ELCA has become one of the essential atherectomy tools offering unique advantages over other atherectomy devices. In the modern era, ELCA is commonly used for patients with in-stent restenosis, stent under expansion, balloon uncrossable lesions and chronic total occlusions. Technical success rates are reported to be >80% in most situations while procedural complication rates such as vessel dissection and perforation among others are reported to average 9% over the past 25 years with improvement over time. In this review, we provide a comprehensive systematic review of the ELCA system, its practical use, indications, and procedural techniques in the contemporary PCI era.

Excimer laser in contrast for the treatment of acute MI caused by thrombosis of underexpanded stent

The use of excimer laser with contrast for treating an underexpanded stent in the setting of subacute stent thrombosis and hemodynamic instability is described. The patients presented with acute coronary syndromes and cardiogenic shock resulting from stent thrombosis of underexpanded stents. The stents were recalcitrant to aggressive balloon dilation and in the setting of an acute myocardial infarction; rotational atherectomy is a relative contraindication. The use of concurrent contrast during laser atherectomy resulted in plaque modification and subsequent stent expansion.

The Excimer Laser: Science Fiction Fantasy or Practical Tool?

Nearly 20 years ago, in vitro experiments left no doubt about the fact that laser light can ablate atherosclerotic plaque. The initial enthusiastic results with the technology, particularly in coronary arteries, were followed by reports showing unacceptably high restenosis and complication rates. These poor results were due to the premature application of an underdeveloped technology, a lack of understanding of laser/tissue interaction, and the use of incorrect lasing techniques. Consequently, and without discrimination, all lasers were banned from the catheterization laboratories for nearly a decade. Technological enhancements of the excimer laser, combined with refined catheter lasing techniques, resulted in greater debulking of atherosclerotic material in long superficial femoral artery occlusions. These results triggered the application of the excimer laser technique as an atherectomy tool in more complex lesions below the knee. The multicenter Laser Atherectomy for Critical Ischemia study clearly demonstrated that the excimer laser technology resulted in limb salvage rates >90% in patients with critical limb ischemia (CLI). Furthermore, new clinical results indicate that the excimer laser is very effective in dissolving thrombotic obstructions, redirecting this technology to the coronary field.

The results of the excimer laser in CLI validate the role of the cool laser in treating complex peripheral vascular disease. The results suggest a larger indication for this technology and support a more aggressive use of these interventional techniques in the treatment of this large patient cohort. However, all lasers are not equally effective in debulking atherosclerotic material. Only the athermic process associated with the excimer laser produces a safe and effective endovascular ablation of obstructive atherosclerotic and/or thrombotic material. The appropriate and safe utilization of the equipment and lasing techniques, combined with correct indications and patient selection, will contribute to the successful application of laser-assisted atherectomy in complex peripheral and coronary artery obstructive disease. Unfortunately, little consistent scientific data has been generated to convince the interventional community of the usefulness of excimer laser ablation.

Coronary Intervention with the Excimer Laser: Review of the Technology and Outcome Data

Excimer laser coronary atherectomy (ELCA) is a long-established adjunctive therapy that can be applied during percutaneous coronary intervention (PCI). Technical aspects have evolved and there is an established safety and efficacy record across a number of clinical indications in contemporary interventional practice where complex lesions are routinely encountered. The role of ELCA during PCI for thrombus, non-crossable or non-expandable lesions, chronic occlusions and stent under-expansion are discussed in this review. The key advantage of ELCA over alternative atherectomy interventions is delivery on a standard 0.014-inch guidewire. Additionally, the technique can be mastered by any operator after a short period of training. The major limitation is presence of heavy calcification although when rotational atherectomy (RA) is required but cannot be applied due to inability to deliver the dedicated RotaWire^TM (Boston Scientific), ELCA can create an upstream channel to permit RotaWire passage and complete the case with RA - the RASER technique.

Case-control registry of excimer laser coronary angioplasty versus distal protection devices in patients with acute coronary syndromes due to saphenous vein graft disease

Laser atherectomy might decrease procedural complications during percutaneous coronary intervention (PCI) of degenerated saphenous vein grafts (SVGs) in case of unstable or thrombotic lesions because of its ability to debulk and vaporize thrombus. We aimed at prospectively evaluating the safety and efficacy of excimer laser coronary angioplasty (ELCA) as a primary treatment strategy in consecutively unstable patients undergoing PCI of degenerated SVG lesions. Seventy-one consecutive patients with non-ST elevation acute coronary syndrome (mean age 69 ± 10 years, 66 men [89%]) undergoing PCI of degenerated SVG were enrolled in a prospective case-control registry, using 2 different distal protection devices (DPDs; FilterWire EZ [Boston Scientific, Natick, Massachusetts; n = 24] and SpiderRX [Ev3, Plymouth, Minnesota; n = 23]) or ELCA (n = 24). Primary end points of the study were incidence of angiographic microvascular obstruction (Thrombolysis In Myocardial Infarction flow grade of <3 or Thrombolysis In Myocardial Infraction flow grade of 3 with myocardial blush grade 1 to 2) and incidence of type IVa myocardial infarction. Angiographic microvascular obstruction incidence tended to be less in ELCA-treated patients compared with DPD-treated patients (3 [13%] vs 15 [32%], p = 0.09). Type IVa myocardial infarction incidence was more in DPD-treated patients compared with ELCA-treated patients (23 [49%] vs 5 [21%], p = 0.04). In conclusion, in patients with non-ST elevation acute coronary syndrome undergoing PCI of degenerated SVG, ELCA compared with DPD, is associated with a trend for better myocardial reperfusion and a lesser incidence of periprocedural necrosis. Controlled randomized trials are warranted to confirm these early observations.

Immediate and midterm follow-up results of excimer laser application in complex percutaneous coronary interventions: Report from a single center experience

OBJECTIVE

To assess the efficacy and safety of laser-assisted percutaneous coronary interventions (PCI) in an unselected population.

METHODS

One hundred consecutive patients, who underwent a laser assisted PCI between January 2008 and March 2012, were included in the present study. Fifty-one patients underwent laser ablation for thrombus vaporization (Group 1), 36 patients for neointima/plaque debulking (Group 2) and 13 patients for lesion compliance modification in calcified lesions (Group 3).

RESULTS

The rate of in-hospital serious events was 2%. The cumulative laser success was 82%, and it was significantly higher for Group 1 and Group 2 in comparison with Group 3 (p = 0.001). Furthermore, the need for repeat revascularization was significantly higher in the Group 3 compared with the others two groups (46% vs. 8% for Group 1 and 11% for Group 2, p = 0.03). The MACE rate was 14%. There was a trend toward a higher MACE rate in the Group 3 compared with others two groups (p = 0.05).

CONCLUSIONS

Laser ablation is an effective and safe tool for complex PCI. Patients underwent laser for thrombus vaporization or for neointima/plaque debulking had better immediate success and better outcome at follow-up than patients underwent laser for lesion compliance modification.

A Novel Minimally Occlusive Microvascular Anastomosis Technique Using a Temporary Intraluminal Shunt: A Prospective Technique to Minimize Brain Ischemia Time during Superficial Temporal Artery-to-Middle Cerebral Artery Bypass

OBJECTIVE:

To describe a new technique of suturing microvessels with persistent perfusion via a temporary intraluminal microshunt.

METHODS:

Experiments were conducted in Wistar rats. Abdominal aorta grafts were explanted from donor rats. A soft silicon microcatheter was introduced into the lumen of this graft. The abdominal aorta of a recipient rat was prepared for end-to-side microvascular anastomosis. Acland clamps (S&T AG, Neuhausen, Switzerland) were applied, and a linear arteriotomy was made. One end of the graft-clad microcatheter was introduced into the lumen and occluded with a fenestrated Acland clamp. At a more distal part, a similar arteriotomy was performed, and the other end of the microcatheter was introduced into the lumen and clamped with a fenestrated Acland clip. This created a temporary shunt through the graft-clad microcatheter. Then, the graft was anastomosed to the arteriotomies at both ends, over the microcatheter, in an end-to-side manner. The microcatheter was explanted from the vessel lumen through an arteriotomy in the middle of the graft. The graft was clipped short to close this arteriotomy. The mean total occlusion time before perfusion was reestablished amounted to 3.7 minutes. This experiment was repeated in 12 animals (6 with and 6 without heparin) without technical complications. As controls, conventional anastomoses were made in 2 animals.

RESULTS:

Suturing microvessels mandates their occlusion during the period of anastomosis. Although ischemia is well tolerated by other tissue types, the brain is quite sensitive to even short windows of ischemia. Nonocclusive anastomotic techniques have been developed recently. These are confined to vessels with luminal diameters greater than 3 mm. We have evolved a novel technique that can be used with microvessels, as pertinent to superficial temporal artery-to-middle cerebral artery bypass.

CONCLUSION:

We have described a new technique for performing microvascular anastomoses over a temporary intraluminal microcatheter shunt.

Embolic protection during saphenous vein graft intervention using a second-generation balloon protection device: results from the combined US and European pilot study of the TriActiv Balloon Protected Flush Extraction System

BACKGROUND

Stent placement in saphenous vein bypass grafts is associated with a high incidence of myonecrosis usually resulting from embolization of thrombus and friable atheroma. Embolic protection devices reduce the incidence of adverse events after vein graft stenting. However, first-generation balloon occlusion systems are still associated with a 10% incidence of periprocedural adverse events. We report the first experience with a new second-generation balloon occlusion embolic protection device, the TriActiv Balloon Protected Flush Extraction System.

METHODS

Ninety-six lesions in 78 saphenous vein grafts were treated in 74 patients. The primary end point was major adverse cardiovascular events at 30 days.

RESULTS

Device success was achieved in 92% of patients, and atheromatous debris was recovered in 69% of analyzed aspirates. By 30 days, major adverse cardiovascular events, which were limited to non-Q-wave myocardial infarctions, occurred in 16.2%. Per protocol analysis in patients with device success revealed a rate of adverse events of only 5.7%.

CONCLUSIONS

The initial experience with the TriActiv Balloon Protected Flush Extraction System demonstrated a high success rate and recovery of embolic debris with an acceptable rate of adverse events. A large randomized trial will compare this device to other embolic protection systems.

The excimer laser: science fiction fantasy or practical tool?

Nearly 20 years ago, in vitro experiments left no doubt about the fact that laser light can ablate atherosclerotic plaque. The initial enthusiastic results with the technology, particularly in coronary arteries, were followed by reports showing unacceptably high restenosis and complication rates. These poor results were due to the premature application of an underdeveloped technology, a lack of understanding of laser/tissue interaction, and the use of incorrect lasing techniques. Consequently, and without discrimination, all lasers were banned from the catheterization laboratories for nearly a decade. Technological enhancements of the excimer laser, combined with refined catheter lasing techniques, resulted in greater debulking of atherosclerotic material in long superficial femoral artery occlusions. These results triggered the application of the excimer laser technique as an atherectomy tool in more complex lesions below the knee. The multicenter Laser Atherectomy for Critical Ischemia study clearly demonstrated that the excimer laser technology resulted in limb salvage rates >90% in patients with critical limb ischemia (CLI). Furthermore, new clinical results indicate that the excimer laser is very effective in dissolving thrombotic obstructions, redirecting this technology to the coronary field. The results of the excimer laser in CLI validate the role of the cool laser in treating complex peripheral vascular disease. The results suggest a larger indication for this technology and support a more aggressive use of these interventional techniques in the treatment of this large patient cohort. However, all lasers are not equally effective in debulking atherosclerotic material. Only the athermic process associated with the excimer laser produces a safe and effective endovascular ablation of obstructive atherosclerotic and/or thrombotic material. The appropriate and safe utilization of the equipment and lasing techniques, combined with correct indications and patient selection, will contribute to the successful application of laser-assisted atherectomy in complex peripheral and coronary artery obstructive disease. Unfortunately, little consistent scientific data has been generated to convince the interventional community of the usefulness of excimer laser ablation.

Distal filter protection during saphenous vein graft stenting: technical and clinical correlates of efficacy

OBJECTIVES

The aim of this study was to evaluate the clinical, angiographic, and technical factors related to successful stenting of diseased saphenous vein grafts (SVGs) using a novel filter-based distal protection device.

BACKGROUND

Protection of the distal microvasculature with a balloon occlusion and aspiration system has been shown to reduce atherothrombotic embolization and peri-procedural myocardial infarction (MI) after percutaneous coronary intervention (PCI) in SVGs. The safety, efficacy, and technical factors relating to procedural success with filter-based distal protection devices are unknown.

METHODS

Percutaneous coronary intervention was performed in 60 lesions in 48 patients undergoing SVG intervention with the FilterWire EX distal protection system in a phase I experience at six sites. A larger phase II study was then performed in 248 lesions in 230 SVGs at 65 U.S. centers.

RESULTS

Cumulative adverse events to 30 days occurred in 21.3% of patients in phase I, including a 19.1% rate of MI. Numerous anatomic, device-specific, and operator-related contributors to these adverse events were identified, resulting in significant changes to the protocol and instructions for use. Subsequently, despite similar clinical and angiographic characteristics to the phase I patients, the 30-day adverse event rate in phase II was reduced to 11.3% (p = 0.09), due primarily to a lower incidence of peri-procedural Q-wave and non-Q-wave MI.

CONCLUSIONS

Distal protection during SVG PCI with the FilterWire EX is associated with a low rate of peri-procedural adverse events compared to historical controls. A unique set of anatomic, technical, and operator-related issues exist with distal filters which, if ignored, may reduce their effectiveness.

Stent deployment with distal vascular protection for the culprit vein graft stenosis in a patient with an acute infarct and cardiogenic shock

A case of emergency stent deployment to a critical vein graft lesion in a patient with an acute myocardial infarction and cardiogenic shock is described. An Angioguard vascular protection device was used, retrieving a large amount of atheromatous debris. Use of filter-type protection devices to prevent distal atheroembolism may be lifesaving in such patients.

Laser coronary angioplasty: history, present and future

The efficacy of percutaneous transluminal coronary angioplasty (PTCA) is limited by remaining plaque tissue and the development of restenosis. It has been demonstrated that the restenosis rate is low if a large lumen diameter is achieved after coronary intervention. Debulking of coronary stenoses is a concept to increase the luminal diameter after intervention. Laser angioplasty debulks coronary stenoses by ablation of atherosclerotic plaque. Since the first intravascular laser intervention, the technique has been significantly improved by the use of optimized wavelength, the development of flexible optimally spaced multifiber catheters and an additional saline flush technique. These technical advancements allowed a reduction in the incidence of adverse events, such as the number of dissections and perforations, associated with the use of the laser technique. Coronary laser angioplasty is commonly combined with adjunctive balloon angioplasty to optimize the outcome. Laser coronary angioplasty was not followed by a lower restenosis rate compared with plain balloon angioplasty in lesions without stents, however, a randomized comparison of the techniques including the use of the saline flush technique is not available yet. The value of excimer (acronym for excited dimer) laser coronary angioplasty for treatment of in-stent restenosis is still under investigation. So far, nonrandomized single center studies have not suggested a relevant benefit for this technique used for in-stent restenosis. In nonstented lesions there remain niche indications for laser angioplasty such as the treatment of ostial lesions, diffuse lesions or lesions traversable with a guidewire but not with an angioplasty balloon. Laser coronary angioplasty may also be useful after a failed balloon angioplasty and in patients with chronic total occlusions. The potential advantages of combining laser coronary angioplasty with vaporization of thrombus in patients with acute coronary syndromes are currently under evaluation.

Prevention of distal embolization during coronary angioplasty in saphenous vein grafts and native vessels using porous filter protection

BACKGROUND

Although distal embolization and the "no-reflow" phenomenon are well described in saphenous vein graft (SVG) interventions, the frequency, magnitude, and characterization of embolized debris have not been evaluated in routine coronary interventions. A unique embolus protection device described herein provides a means of containing and retrieving plaque material dislodged during percutaneous coronary interventions. This report details the first clinical experience of the effectiveness and safety of an emboli protection system in 11 SVG lesions and 15 native coronary artery lesions.

METHODS AND RESULTS

The AngioGuard Emboli Capture Guidewire (Cordis) consists of a PTCA wire with an expandable filter at the distal tip. The porous membrane permits normal distal blood flow, while trapping potential emboli by filtration. After crossing the lesion, the filter is expanded, and routine angioplasty is performed over the same wire. Emboli retrieval is achieved by collapsing the filter and retracting the emboli capture wire (ECW). In 26 patients, standard angioplasty was performed over the ECW; 20 of these 26 patients received a stent. Collected debris was sent for histopathological analysis. Plaque debris was retrieved after native coronary and SVG interventions in all cases. The ECW was positioned and retrieved without complications. No major adverse events occurred. Myocardial infarctions and no-reflow were not observed.

CONCLUSIONS

The embolization of plaque fragments frequently occurs during coronary and SVG intervention. Distal embolization leading to microvascular obstruction and no-reflow could be successfully minimized by using the ECW.

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.

Initial experience with a low profile, high energy excimer laser catheter for heavily calcified coronary lesion debulking: parameters and results of first seven human case experiences

BACKGROUND

Excimer laser coronary angioplasty (ELCA) has not been used in the setting of highly calcified, tight stenoses because the energies required to use existing catheters would lead to excessive heat damage and dissection. There are, however, cases that frequently benefit from debulking prior to percutaneous intervention. A new, small laser catheter capable of high energies and repetition was previously examined in vitro. This study describes the first in vivo use.

PURPOSE

To determine the safety and feasibility of a new, low profile, high energy laser catheter for creating a pilot hole to facilitate coronary angioplasty and stenting in patients with heavily calcified and occluded coronary arteries where a balloon has either failed to pass or was predicted to perform poorly. These patients represent the first patients treated with this new catheter.

METHODS

At a high volume center, seven consecutive patients with anatomy as summarized above were treated and studied with QCA and then followed for 30 days postprocedure for complications and Canadian Cardiovascular Society (CCS) angina class.

RESULTS

The laser catheter crossed five out of seven lesions and partially penetrated the remaining lesions. The mean maximum luminal diameter (MLD) postlasing was 1.0 mm with Thrombolysis in Myocardial Infarction (TIMI) 3 flow. It was possible to easily balloon and stent after the pilot hole creation in all but one patient. TIMI 3 was achieved for the final result after adjunct therapy in all patients. All patients except one, who died at 3 months postprocedure of stroke, were improved by an average of two angina classes. No late procedural-related complications developed.

CONCLUSIONS

The new, low profile laser catheter is easy to use and achieved good results in cases where a balloon either failed to pass or was predicted to give poor results. Further trials are warranted for this niche technology.

Balloon occlusion and transluminal aspiration of saphenous vein grafts to prevent distal embolization

Distal embolization is a common complication of percutaneous intervention in saphenous vein grafts. This may lead to the "no reflow" phenomenon and subsequent myocardial infarction. We describe a case in which we occluded the distal portion of a saphenous vein graft with a balloon to prevent distal embolization, performed percutaneous transluminal coronary angioplasty, and then successfully aspirated the particulate debris with a Dorros/Probing catheter.

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.

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.

Prevention of distal embolization during saphenous vein graft lesion angioplasty. Experience with a new temporary occlusion and aspiration system

BACKGROUND

Repeat coronary artery bypass graft surgery (CABG) is associated with a high morbidity and mortality, rendering percutaneous treatment of saphenous vein graft (SVG) lesions an attractive alternative. However, percutaneous interventions of degenerated SVGs carries high risk of distal embolization.

METHODS AND RESULTS

This study reports our initial experience with the PercuSurge GuardWire, a new device developed to prevent embolization during treatment of degenerated SVG. This device consists of a 190-cm-long, hollow 0.014-in guidewire with a central lumen connected to a distal occlusion balloon. A dedicated inflation device (the MicroSeal Adapter) was used to inflate the distal balloon and maintain complete lumen occlusion during balloon dilatation and stent implantation. A monorail aspiration catheter, connected to a vacuum syringe, was used to evacuate atherosclerotic and thrombotic debris. Angioplasty with stent implantation was performed in 15 degenerated SVGs (18 lesions). Procedural success was achieved in all patients with normal postprocedure flow (Thrombolysis in Myocardial Infarction grade 3). No distal embolization was observed. There were no major in-hospital adverse clinical events, including Q-wave or non-Q-wave myocardial infarction, emergency CABG, or death. All patients were asymptomatic at discharge.

CONCLUSIONS

This preliminary series supports the feasible use of the PercuSurge GuardWire for retrieval of plaque debris and prevention of embolization in degenerated SVGs. The good tolerance of temporary occlusions without angiographic or clinical evidence of distal embolization represents encouraging early findings.

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.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part V

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effect on the site of obstruction has been termed "remodeling." Part V of this six-part series focuses on remodeling effects of balloon angioplasty on obstructed young (< or = 1 year) and old (> 1 year) saphenous vein bypass grafts.

Excimer laser-facilitated angioplasty for undilatable coronary narrowings

Calcified and fibrotic coronary artery lesions cannot always be dilated with conventional balloon angioplasty even at high pressures. This study examines the success of excimer laser facilitated angioplasty in 38 lesions in 37 patients with lesions that failed balloon angioplasty alone.

Percutaneous transcatheter therapy of aorto-ostial stenoses

The treatment of native coronary and saphenous vein graft aorto-ostial stenoses with balloon angioplasty (PTCA) has been associated with lower procedural success rates, more frequent in-hospital complications and a greater likelihood of late restenosis when compared with PTCA of non-ostial stenoses. The advent of ablative technologies and intracoronary stents have significantly altered both early and late outcomes of percutaneous intervention for aorto-ostial disease. The optimal approach to this complex lesion subset often involves decalcification or tissue ablation followed by stent deployment. Improvements in currently available stent technology including enhanced radial force and visibility, reduced thrombogenicity, and the availability of shorter stent lengths, may also facilitate stent deployment and further improve outcomes following percutaneous transcatheter therapy for aorto-ostial stenoses.

Excimer laser angioplasty vs. balloon angioplasty in saphenous vein bypass grafts: quantitative angiographic comparison of matched lesions

Technologies which ablate or debulk tissue may result in better angiographic outcomes by altering the elastic properties of the vessel wall. Accordingly, the procedural outcomes of 88 vein graft lesions treated by either excimer laser angioplasty with adjunct balloon angioplasty (PELCA + PTCA, n = 44) (Spectranetics CVX-300, 1.4-, 1.7-, or 2.0-MM catheters) or balloon angioplasty alone (PTCA, n = 44) were analyzed by quantitative angiography (Cardiac Measurement System). Lesions were individually matched for vessel position, reference diameter (RD), and minimal luminal diameter (MLD). Matching was deemed adequate as the preprocedure MLD (PELCA + PTCA, 1.14 +/- 0.48 mm; PTCA, 1.20 +/- 0.47 mm) and RD (PELCA + PTCA, 3.23 +/- 0.56 mm; PTCA, 3.25 +/- 0.57 mm) were not significantly different. There were also no significant differences between PELCA + PTCA- and PTCA-treated lesions with respect to patient age, graft age, lesion length, symmetry, and plaque area. Balloon diameter at maximal inflation was 2.77 +/- 0.55 mm (PELCA + PTCA group) and 2.84 +/- 0.59 mm (PTCA group), P = NS. Final MLD postprocedure was 2.17 +/- 0.54 mm and 2.19 +/- 0.55 mm for PELCA + PTCA- and PTCA-treated lesions (P = NS), respectively. Vessel stretch [(balloon diameter - MLD pre)/RD], elastic recoil [(balloon diameter - MLD post)/RD], and acute gain [(MLD post - MLD pre)/RD] were calculated and normalized for vessel size (RD). Vessel stretch (PELCA + PTCA, 0.60 +/- 0.22; PTCA, 0.59 +/- 0.24; P = NS), elastic recoil (PELCA + PTCA, 0.28 +/- 0.18; PTCA, 0.26 +/- 0.16), and acute gain (PELCA + PTCA, 0.34 +/- 0.24; PTCA, 0.31 +/- 0.23; P = NS) were not significantly different between the two treatment groups. In a matched population of successfully treated vein graft lesions, PELCA + PTCA did not reduce elastic recoil or improve immediate angiographic outcome, as compared with PTCA alone.

Immediate results and late outcomes after stent implantation in saphenous vein graft lesions: the multicenter U.S. Palmaz-Schatz stent experience. The Palmaz-Schatz Stent Study Group

OBJECTIVES

This study reports the multicenter registry experience evaluating the safety and efficacy of the Palmaz-Schatz stent in the treatment of saphenous vein graft disease.

BACKGROUND

Saphenous vein graft angioplasty is associated with frequent periprocedural complications and a high frequency of restenosis. Stent implantation has been shown to reduce restenosis, with improved long-term outcomes in the treatment of native coronary artery disease. Preliminary experience with stent placement in the treatment of saphenous vein graft lesions has been favorable.

METHODS

Twenty U.S. investigator sites enrolled a total of 589 symptomatic patients (624 lesions) for treatment of focal vein graft stenoses between January 1990 and April 1992. Follow-up angiography was performed at 6 months, and the clinical course of all study patients was prospectively collected at regular intervals for up to 12 months.

RESULTS

Stent delivery was successful in 98.8% of cases, and the procedural success rate was 97.1%. The lesion diameter stenosis decreased from 82 +/- 12% (mean +/- SD) before to 6.6 +/- 10.2% after treatment. Major in-hospital complications occurred in 17 patients (2.9%); stent thrombosis was found in 8 (1.4%); and major vascular or bleeding complications were noted in 83 (14.3%). Six-month angiographic follow-up revealed an overall restenosis rate (> or = 50% diameter stenosis) of 29.7%. Multivariate logistic regression analysis indicated that 1) restenotic lesions, 2) smaller reference vessel size, 3) history of diabetes mellitus, and 4) higher percent poststent diameter stenosis were independent predictors of restenosis. The 12-month actuarial event-free survival was 76.3%.

CONCLUSIONS

Stent implantation in patients with focal saphenous vein graft lesions can be achieved with a high rate of procedural success, acceptable major complications, reduced angiographic restenosis and favorable late clinical outcome compared with historical balloon angioplasty control series. The rigorous anticoagulation regimen after stent placement results in more frequent vascular and other bleeding complications. Future randomized studies comparing standard balloon angioplasty with stent implantation are warranted to properly assess the full impact of stent placement in the treatment of saphenous vein graft lesions.

Early and late quantitative angiographic results of vein graft lesions treated by excimer laser with adjunctive balloon angioplasty

BACKGROUND

Percutaneous excimer laser coronary angioplasty (PELCA) has been approved for treatment of diseased saphenous vein bypass grafts. However, detailed and complete quantitative angiographic analysis of immediate procedural and late follow-up results has not been performed.

METHODS AND RESULTS

PELCA using the CVX-300 excimer laser system was performed in 125 bypass lesions (mean graft age, 96 +/- 53 months; range, 2 to 240 months) in 106 consecutive patients at eight centers. Quantitative analyses of the procedural and follow-up angiograms were done with the Cardiac Measurement System. Stand-alone PELCA was done in 21 lesions (17%). Lesions were located at the ostium (20%), body (67%), or distal anastomosis (13%). The graft reference diameter was 3.26 +/- 0.79 mm (mean +/- SD). Minimal lumen diameter increased from 1.09 +/- 0.52 mm before treatment to 1.61 +/- 0.69 mm after laser and 2.18 +/- 0.63 mm after adjunctive balloon dilation (P < .001) but had declined at follow-up to 1.40 +/- 1.17 mm. Dissections were evident in 45% of lesions after laser treatment (types A and B, 27%; types C through F, 18%), including 7% occlusions. Angiographic success (< or = 50% diameter stenosis [% DS]) was 54% after laser and 91% after adjunctive PTCA, with an overall clinical success rate of 89%. In-hospital complications were death, 0.9%; myocardial infarction (Q-wave and non-Q-wave), 4.5%; and bypass surgery, 0.9%. Independent predictors of % DS after laser were reference diameter, lesion length, and minimal lumen diameter before laser. At angiographic follow-up in 83% of eligible patients, the restenosis rate per lesion (DS > 50%) was 52%, including 23 occlusions (24%). The only independent predictor of increased % DS at follow-up was lesion symmetry. Logistic regression indicated that smaller reference diameter was an independent predictor of late occlusion. Overall 1-year mortality was 8.6%. Actuarial event-free survival (freedom from death, myocardial infarction, bypass surgery, or target vessel percutaneous transluminal coronary angioplasty) was 48.2% at 1 year.

CONCLUSIONS

Excimer laser angioplasty with adjunctive balloon angioplasty can be safely and successfully performed in diseased, old saphenous vein bypass graft lesions considered at high risk for reintervention. The extent of laser ablation remains limited by the diameter and effectiveness of the catheters. Late restenosis and, in particular, total occlusion mitigate the early benefits of the procedure. Other approaches such as the routine use of additional anticoagulation (eg, warfarin) should be considered to reduce the risk of late occlusions and restenosis after laser angioplasty of bypass grafts.