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

Distal embolic protection during percutaneous coronary intervention in patients with acute coronary syndromes: The RUBY study

OBJECTIVE

To assess the safety and feasibility of the GuardWire system as an embolic protection device during percutaneous coronary intervention (PCI) in acute coronary syndromes (ACS).

BACKGROUND

Distal embolization occurs in approximately 15% of patients after primary angioplasty and is associated with reduced myocardial reperfusion, more extensive myocardial damage and a poor prognosis. Distal embolic protection could reduce the rate of embolic complications and improve outcome.

METHODS

329 patients (mean age 60+/-12 years) were included: 278 (84.5%) with ST-elevation myocardial infarction (STEMI), 50 (15.2%) with unstable angina/non-STEMI and 1 (0.3%) with post-infarction angina. Primary endpoint was the incidence of major adverse cardiac events (MACE) at 30 days. Secondary endpoints were the magnitude of ST-segment resolution at 90 and 180 min post-procedure, myocardial blush grade, and angiographically visible distal emboli.

RESULTS

The GuardWire system was successfully positioned in 99% of patients. Complete ST-elevation resolution (>70%) was observed in 28.5% immediately post-procedure, and in 35.4% and 41.6% at 90 and 180 min post-procedure. TIMI-3 flow grade was achieved by 89.8% of patients after intervention and mean corrected TIMI frame count was 20.2+/-13.2. Grade-3 myocardial blush was seen in 47.7% of patients and distal emboli were angiographically visible in 7.4%. Incidence of MACE at 30 days was 3.3% (death 1.2%; Q-wave MI 0.3%; non-Q-wave MI 0.3%; coronary artery bypass graft 0.6%; repeat PCI 0.9%).

CONCLUSION

The GuardWire system was successfully positioned in nearly all patients without complications. The use of this embolic protection device in ACS patients undergoing PCI was associated with low rates of distal embolization and 30-day MACE.

Clinical experiences using the FilterWire EX for distal embolic protection during complex percutaneous coronary interventions

BACKGROUND

Distal embolization during coronary angioplasty may result in vessel occlusion, no reflow and myonecrosis. This study tested the authors' clinical experiences using a guidewire system designed to preserve distal flow during angioplasty.

METHODS AND RESULTS

The FilterWire EX trade mark (Boston Scientific, Natick, MA, USA) consists of a 0.014-inch guidewire on which an expandable loop structure is attached to a porous polyurethane membrane. The assembly is delivered across the target lesion, followed by deployment of the filter distal to the lesion. Procedural and angiographic outcome data were obtained from patients undergoing saphenous vein grafts (SVGs) (n = 16) or native coronary (n = 4) interventions. The mean age was 62 +/- 10 years. All four patients with native coronary lesions sustained acute myocardial infarction while 15/16 patients with degenerated SVGs presented with accelerated angina pectoris. The mean proximal reference diameter was 3.62 +/- 0.32 mm, percentage diameter stenosis was 72 +/- 13%, and lesion length was 16.3 +/- 5.7 mm. Angiographic visible thrombus was detected in 12/20 (60%) cases. Stents were used in 19/20 patients (95%) with average stent diameter/length equal to 3.81 +/- 0.42/23 +/- 7 mm. Overall procedural success was obtained in 93.3% as no-reflow and total CK elevation occurred in 1/16 treated patients (6.7%) despite distal embolic filtration. In-hospital and 30-day survival was 100% with no episodes of target vessel thrombosis and/or myocardial infarction.

CONCLUSIONS

The use of the FilterWire EX seems to be feasible and safe in suitable lesion subsets and in relatively large-sized vessels among patients who are at high risk for distal embolization.

Distal protection device protects microvascular integrity during primary percutaneous intervention in acute myocardial infarction: A prospective, randomized, multicenter trial

BACKGROUND

Distal protection during primary angioplasty in acute myocardial infarction (AMI) is the subject of recent controversy. The present study was designed to determine whether the distal embolic protection preserves myocardial microvascular integrity and improves clinical outcomes in patients with AMI.

METHODS

A total of 116 AMI patients presenting within 12 h of onset of symptoms were enrolled at 7 angioplasty centers. They were randomly assigned to either primary angioplasty with distal protection group (DP; n=60) or angioplasty alone group (Controls; n=56).

RESULTS

After primary angioplasty, achievement of final Thrombolysis In Myocardial Infarction (TIMI) grade 3 and TIMI Myocardial Perfusion (TMP) grade 3 were more frequent in the DP group than in the control group [58/60 (96%) vs. 43/56 (81%), p=0.016; and 39/60 (65%) vs. 20/56 (38%), p=0.001, respectively]. After primary angioplasty, the baseline and hyperemic averaged peak velocities were significantly higher (23.2+/-11.5 vs. 18.0+/-6.9 cm/s, p=0.029; and 39.2+/-16.7 vs. 30.6+/-10.8 cm/s, p=0.014, respectively) and the baseline and hyperemic microvascular resistance indices were significantly lower (4.18+/-2.22 vs. 5.34+/-2.25 mm Hg cm(-1) s, p=0.036; and 2.38+/-1.39 vs. 3.11+/-1.32 mm Hg cm(-1) s, p=0.030, respectively) in the DP group. Patients in the DP group showed more favorable phasic coronary flow pattern in diastolic deceleration time (679+/-262 vs. 519+/-289 ms, p=0.035; and 751+/-246 vs. 616+/-269 ms, p=0.035, respectively). Major adverse cardiac events at 6 months occurred with similar frequency in both groups (8.7% vs. 11.1%, p=0.400).

CONCLUSIONS

Distal protection device effectively preserves microvascular integrity during primary angioplasty in AMI. Distal protection, however, did not improve clinical outcomes.

Cerebral ischemia detected with diffusion-weighted MR imaging after protected carotid artery stenting: comparison of distal balloon and filter device

Objective

The aim of this study was to examine the incidence of ischemia during protected carotid artery stenting (CAS) as well as to compare the protective efficacy of the balloon and filter devices on diffusion-weighted MR imaging (DWI).

Materials and Methods

Seventy-one consecutive protected CAS procedures in 70 patients with a severe (> 70%) or symptomatic moderate (> 50%) carotid artery stenosis were examined. A balloon device (PercuSurge GuardWire) and a filter device (FilterWire EX/EZ, Emboshield) was used in 33 cases (CAS-B group) and 38 cases (CAS-F group) to prevent distal embolization, respectively. All the patients underwent DWI within seven days before and after the procedures. The number of new cerebral ischemic lesions on the post-procedural DWI were counted and divided into ipsilateral and contralateral lesions according to the relationship with the stenting side.

Results

New cerebral ischemic lesions were detected in 13 (39.4%) out of the 33 CAS-Bs and in 15 (39.5%) out of the 38 CAS-Fs. The mean number of total, ipsilateral and contralateral new cerebral ischemic lesion was 2.39, 1.67 and 0.73 in the CAS-B group and 2.11, 1.32 and 0.79 in the CAS-F group, respectively. No statistical differences were found between the two groups (p = 0.96, 0.74 and 0.65, respectively). The embolic complications encountered included two retinal infarctions and one hemiparesis in the CAS-B group (9.09%), and one retinal infarction, one hemiparesis and one ataxia in the CAS-F group (7.89%). There was a similar incidence of embolic complications in the two groups (p = 1.00).

Conclusion

The type of distal protection device used such as a balloon and filter does not affect the incidence of cerebral embolization after protected CAS.

Automatic Detection of Microemboli During Percutaneous Coronary Interventions

The objective of this study was to develop an analysis method for the automatic detection of intracoronary microemboli triggered high intensity signals (HITS) during percutaneous coronary interventions (PCI). The recorded ultrasonic Doppler velocity spectra from an intracoronary ultrasonic guide-wire were decomposed into 13 wavelet scales applying the continuous wavelet transform. From 7 wavelet scales which were most suitable for a differentiation between HITS and pulsatile flow, envelopes were calculated and combined to improve the HITS-to-background noise ratio. For different intensity thresholds the resulting number of HITS was automatically counted and compared with the number estimated by experienced observers. In a first validation trial HITS were detected within a simplified in vitro model with a sensitivity of 89.2% and a positive predictive value of 87.6%. In a following clinical study 211 HITS from 18 patients during PCI were counted manually by the observers. With the developed wavelet-based method 189 HITS were correctly detected (sensitivity of 89.6%, positive predictive value of 85.5%). The introduced new method automatically detects intracoronary HITS for the first time with a reliable accuracy. This may support further studies evaluating the incidence and consequences of coronary microembolization during coronary interventions.

Thrombosuction utilizing an export aspiration catheter during primary percutaneous coronary intervention in acute myocardial infarction

PURPOSE

Effective myocardial reperfusion after primary PCI for an AMI in lesions with a thrombus is limited by distal embolization and the slow/no reflow phenomenon. We evaluated the efficacy of a thrombus reduction technique using an export aspiration catheter for thrombosuction during primary PCI.

MATERIALS AND METHODS

We analyzed 62 patients with AMIs who underwent primary PCI and had a thrombi burden during thrombosuction using an EAC (EAC group; n=31) or without thrombosuction (control group; n=31).

RESULTS

Thrombosuction with an EAC was performed safely in all the patients in EAC group without any complications. After the PCI, restoration to a TIMI flow grade 3 was significantly more frequent in the EAC group (26/31 vs. 20/31, p < 0.05). However, the TIMI perfusion grade did not differ between the two groups. Further, the corrected TIMI frame counts were lower in the EAC group (23.9 +/- 15.1 vs. 34.8 +/- 22.5, p < 0.05). Although there was no statistical significance, a greater incidence of distal embolization was observed in the control group (16.1%, 5/31) as compared to the EAC group (0/31) (p= 0.056). However, the incidence of major adverse cardiac events at 1 and 6 months did not differ between the two groups.

CONCLUSION

For AMIs, thrombosuction with an EAC before or during PCI is a safe and potentially effective method for restoration of the coronary flow.

Predictors of periprocedural creatine kinase-myocardial band elevation complicating elective percutaneous coronary intervention

Limited data are available regarding the predictors of periprocedural creatine kinase-MB (CK-MB) isoenzyme increase after elective percutaneous coronary intervention (PCI) in the stenting era. We explored the predictors of periprocedural CK-MB increase in 882 consecutive patients with normal preprocedural CK-MB who underwent 919 angiographically successful elective PCIs with (n = 814) or without (n = 105) stenting. Patients were categorized into 3 groups based on their peak CK-MB levels after PCI: (1) normal CK-MB (n = 761), (2) minor CK-MB increase (CK-MB 1 to 3 times normal, n = 112), and (3) major CK-MB increase (CK-MB >3 times normal, n = 46). By logistic regression analysis, independent predictors for minor CK-MB increase included thrombus (odds ratio [OR] 5.09, p = 0.001), platelet IIb/IIIa antagonist use (OR 0.53, p <0.01), number of lesions treated (per additional lesion, OR 1.54, p <0.01), maximum balloon size (per millimeter increase, OR 1.57, p <0.05), American College of Cardiology/American Heart Association type C lesion (OR 1.68, p <0.05), sustained chest pain during procedure (OR 1.94, p <0.05), dissection (OR 2.05, p <0.05), and transient side branch occlusion (OR 4.54, p <0.05). Independent predictors for major CK-MB increase were chest pain at end of procedure (OR 9.66, p <0.001), type C lesion (OR 2.42, p <0.05), Canadian Cardiovascular Society angina class III to IV (OR 3.32, p <0.05), thrombus (OR 5.09, p = 0.001), and abrupt closure (OR 5.30, p <0.05). In conclusion, baseline clinical and angiographic characteristics and procedural complications were associated with minor and major CK-MB increases. Patients with chest pain at the end of the procedure were at the highest risk for major CK-MB increase.

Adjunctive mechanical devices to prevent distal embolization in patients undergoing mechanical revascularization for acute myocardial infarction: a meta-analysis of randomized trials

BACKGROUND

The benefits of adjunctive mechanical devices to prevent distal embolization in patients with acute myocardial infarction (AMI) are still a matter of debate. The aim of this meta-analysis was to combine data from all randomized trials conducted with adjunctive mechanical devices to prevent distal embolization in AMI.

METHODS

The literature was scanned by formal searches of electronic databases (MEDLINE and Central) from January 1990 to October 2006, scientific session abstracts (from January 1990 to October 2006), and oral presentation and/or expert slide presentations (from January 2002 to October 2006) (on the Transcatheter Cardiovascular Therapeutics, American Heart Association, European Society of Cardiology, American College of Cardiology, and European Percutaneous Revascularization Web sites). We examined all randomized trials on adjunctive mechanical devices to prevent distal embolization in AMI. The following key words were used: randomized trial, myocardial infarction, reperfusion, primary angioplasty, rescue angioplasty, thrombectomy, thrombus aspiration, proximal or distal protection device, X-sizer, Diver, Export Catheter, Angiojet, Rescue catheter, Pronto catheter, PercuSurge, GuardWire, FilterWire, and SpideRX. Disagreements were resolved by consensus.

RESULTS

A total of 21 trials with 3721 patients were included (1877 patients [50.4%] in the adjunctive mechanical device group and 1844 [49.6%] in the control group); 1502 patients (40.3%) were randomized in trials with distal protection devices, and 2219 patients (59.7%) were randomized in trials with thrombectomy devices. Adjunctive mechanical devices were associated with a higher rate of postprocedural TIMI 3 flow (89.4% vs 87.1%, P = .03), a significantly higher rate of postprocedural myocardial blush grade 3 (48.8% vs 36.5%, P < .0001), and less distal embolization (6.0% vs 9.3%, P = .008), without any benefit in terms of 30-day mortality (2.5% vs 2.6%, P = .88). No difference was observed in terms of coronary perforations (0.27% vs 0.07%, P = .24).

CONCLUSIONS

This meta-analysis demonstrates that, among patients with AMI treated with percutaneous coronary intervention, the use of adjunctive mechanical devices to prevent distal embolization is associated with better myocardial perfusion and less distal embolization, but without an apparent improvement in survival.

The no-reflow phenomenon: A basic mechanism of myocardial ischemia and reperfusion

Both animal models of experimental myocardial infarction and clinical studies on reperfusion therapy for acute myocardial infarction have provided evidence of impaired tissue perfusion at the microvascular level after initiation of reperfusion despite adequate restoration of epicardial vessel patency. Characteristics of this "no-reflow" phenomenon found in basic science investigations, such as distinct perfusion defects, progressive decrease of resting myocardial flow with ongoing reperfusion and functional vascular alterations are paralleled by clinical observations demonstrating similar features during the course of reperfusion. In experimental animal investigations of coronary occlusion and reperfusion, this no-reflow phenomenon could be characterized as a fundamental mechanism of myocardial ischemia and reperfusion. Major determinants of the amount of no-reflow are the duration of occlusion, infarct size, but also the length of reperfusion, as rapid expansion of perfusion defects occurs during reperfusion. Moreover, no-reflow appears to persist over a period of at least four weeks, a period when major steps of infarct healing take place. The significant association of the degree of compromised tissue perfusion at four weeks and indices of infarct expansion, found in chronic animal models of reperfused myocardial infarction, might be the pathoanatomic correlate for the prognostic significance observed in the clinical setting.

Coronary microembolization

Atherosclerotic plaque rupture is the key event in the pathogenesis of acute coronary syndromes and it also occurs during coronary interventions. Atherosclerotic plaque rupture does not always result in complete thrombotic occlusion of the epicardial coronary artery with subsequent impending myocardial infarction, but may in milder forms result in the embolization of atherosclerotic and thrombotic debris into the coronary microcirculation. This review summarizes the present experimental pathophysiology of coronary microembolization in animal models of acute coronary syndromes and highlights the main consequences of coronary microembolization--reduced coronary reserve, microinfarction, inflammation and oxidative modification of contractile proteins, contractile dysfunction and perfusion-contraction mismatch.Furthermore, the review presents the available clinical evidence for coronary microembolization in patients and compares the clinical observations with observations in the experimental model.

Intense Vasoconstriction in Response to Aspirate From Stented Saphenous Vein Aortocoronary Bypass Grafts

OBJECTIVES

We sought to identify soluble vasoconstrictor substances that are released during stent implantation into saphenous vein aortocoronary bypass grafts.

BACKGROUND

Atherosclerotic saphenous vein aortocoronary bypass grafts are particularly vulnerable to plaque rupture. Protection devices prevent particulate debris from being embolized. Additional soluble vasoconstrictor substances possibly also contribute to impaired microvascular perfusion.

METHODS

Peripheral venous blood (VB) and aspirate (AS) were obtained from 14 patients with a significant stenosis in a saphenous vein graft during stent implantation under protection with a distal balloon occlusion device. In five additional patients, arterial blood (AB) was also taken distal to the stented lesion before intervention. Vasomotor substances in VB, AB, and AS plasma were identified in a bioassay of rat mesenteric arteries with intact (+E) and denuded endothelium (-E). Vasoconstriction was normalized to that induced by potassium chloride depolarization (100%).

RESULTS

Venous blood, AB, and AS plasma induced maximum vasoconstriction within six minutes. The AS plasma induced a vasoconstriction of 138 +/- 13% (-E) and 87 +/- 14% (+E); VB, of 70 +/- 14% (-E) and 23 +/- 4% (+E); and AB plasma obtained before intervention, of 49 +/- 9% (-E) and 36 +/- 8% (+E). The vasoconstrictor potency of AS plasma in endothelium-denuded vessels was related to the severity of anginal symptoms, angiographic stenosis severity, plaque volume, and plaque burden as determined by intravascular ultrasound. The AS plasma-induced vasoconstriction was largely attenuated by combined serotonin/5-hydroxytryptamine (5-HT)(2A/2C)- and 5-HT(1A/1B)-receptor blockade and eliminated by additional thromboxane A2 thromboxane-prostanoid (TP)-receptor blockade.

CONCLUSIONS

Stent implantation releases, apart from and in addition to particulate debris, soluble vasoconstrictor substances that possibly contribute to impaired microvascular perfusion.

Heterogeneity of Myocardial Perfusion in Distal Coronary Embolism with Different Particle Sizes

BACKGROUND

We hypothesized that altered myocardial perfusion distribution patterns could be seen with coronary distal emboli of different particle sizes using myocardial contrast echocardiography.

METHODS

In 16 open-chest anesthetized dogs, microsphere suspensions of 9 or 500 microm in diameter were injected into the left anterior descending coronary artery until the mean left anterior descending coronary artery flow rate was reduced to less than 30% of baseline flow. During baseline conditions and after maximal embolization, real-time myocardial contrast echocardiography was performed by intravenous infusion of an echocontrast agent.

RESULTS

In animals infused with 9-microm microspheres, a transmural perfusion defect was seen at the time of maximal embolization. In contrast, in animals infused with 500-microm microspheres, a subendocardial perfusion defect was observed.

CONCLUSIONS

The particle size of coronary distal emboli affects myocardial perfusion distribution.

Elevation of plasma matrix metalloproteinase-9 in the culprit coronary artery in patients with acute myocardial infarction: clinical evidence from distal protection

BACKGROUND

Although the elevation of circulating plasma matrix metalloproteinase (MMP)-9 levels in patients with acute myocardial infarction (AMI) has been documented, the origin of MMP-9 remains unclear.

METHODS AND RESULTS

Plasma MMP-9 levels in both the peripheral circulation and coronary arteries were measured in patients with AMI (n=23) and with stable angina pectoris (SAP, n=10) during percutaneous coronary intervention (PCI) with a distal protection device. Blood samples were collected from the femoral artery (FA) and the coronary artery before (Initial) and after (Second) dilation of the culprit lesion. Coronary sinus blood samples were obtained immediately after PCI (n=7). Coronary artery plaque fragments were aspirated in patients with AMI (n=20) and compared with those from patients with SAP who underwent directional atherectomy (n=10). MMP-9 levels in Initial and Second were significantly higher in patients with AMI than in patients with SAP (p<0.01). In AMI patients MMP-9 levels were significantly higher in Initial than in the FA (p<0.05), and were further increased in Second (p<0.0001), whereas those in the coronary sinus were similar to the FA. Immunohistochemistry revealed augmented MMP-9 expression in the coronary artery plaque fragments from AMI patients.

CONCLUSIONS

MMP-9 is mainly released into the coronary circulation from the coronary artery plaque in patients with AMI.

A randomized, controlled trial of saphenous vein graft intervention with a filter-based distal embolic protection device: TRAP trial

The purpose of this prospective, multicenter trial was to evaluate the safety and effectiveness of the TRAP Vascular Filtration System (VFS) to reduce embolic complications during stenting of diseased saphenous vein grafts (SVGs). Patients with SVG lesions were randomly assigned to undergo stenting with or without the TRAP device. The trial was designed to enroll 752 randomized patients. However, the sponsor terminated the study after a total of 467 patients (358 randomized) were enrolled because of poor recruitment once another distal protection device was approved for clinical use. The primary study endpoint, major adverse cardiac events at 30 days, occurred in 17.3% of control patients and 12.7% of patients treated with the TRAP device (P = 0.24). There was a trend toward a lower incidence of myocardial infarction in the TRAP group compared with the control group (16.2% vs 10.5%, P = 0.12). This difference was predominantly due to a lower incidence of moderate-large infarction (CKMB >5x) in the TRAP group. Use of the TRAP VFS during SVG intervention was safe and was associated with a trend toward a lower incidence of adverse events, however, due to low enrollment the study lacked sufficient power to detect a significant benefit with the device.

Peri-procedural myocardial injury: 2005 update

During the past three decades, percutaneous coronary intervention has become one of the cardinal treatment strategies for stenotic coronary artery disease. Technical advances, including the introduction of new devices such as stents, have expanded the interventional capabilities of balloon angioplasty. At the same time, there has been a decline in the rate of major adverse cardiac events, including Q-wave acute myocardial infarction, emergency coronary artery bypass grafting, and cardiac death. Despite these advances, the incidence of post-procedural cardiac marker elevation has not substantially decreased since the first serial assessment 20 years ago. As of now, these post-procedural cardiac marker elevations are considered to represent peri-procedural myocardial injury (PMI) with worse long-term outcome potential. Recent progress has been made for the identification of two main PMI patterns, one near the intervention site (proximal type, PMI type I) and one in the distal perfusion territory of the treated coronary artery (distal type, PMI type II) as well as for preventive strategies. Integrating these new developments into the wealth of clinical information on this topic, this review aims at giving a current perspective on the entity of PMI.

Detection of coronary microembolisation by Doppler ultrasound during percutaneous coronary interventions

OBJECTIVE

To validate an intracoronary Doppler ultrasound device for high intensity transient signals (HITS) detection and to assess the incidence of HITS during percutaneous coronary intervention (PCI).

METHODS AND RESULTS

In an in vitro model, particle count and number of HITS detected by an intracoronary 0.014 inch Doppler wire were closely correlated (r = 0.97, p < 0.001). In the clinical study, 32 patients (mean (SD) age 61 (11) years; 23 men, nine women) with coronary artery disease were treated with balloon dilatation and stent implantation for a single vessel stenosis. In these patients HITS were detected during PCI in 84% (27 of 32). Reproducibility (r = 0.99, p < 0.001) and interobserver agreement (r = 0.84, p < 0.001) of HITS counts were significant. The number of HITS after stent implantation was significantly higher than after balloon dilatation (11 (7) v 2 (4), p < 0.001). Postprocedural coronary flow velocity reserve (CFVR) was < 2.0 in 55% (16 of 29) of all patients after balloon dilatation and < 2.0 in 23% (six of 26) after stent implantation. The number of HITS after stent implantation did not differ significantly between patients with CFVR < 2.0 and patients with CFVR > or = 2.0 (12 (8) v 10 (7), not significant).

CONCLUSIONS

Embolic particles can be detected as HITS by an intracoronary Doppler ultrasound device. Coronary microembolism is often observed during PCI, especially after stent implantation. However, the incidence of HITS alone does not explain a reduced CFVR after PCI.

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.

Myonecrosis following stent placement: association between impaired TIMI myocardial perfusion grade and MRI visualization of microinfarction

Contrast-enhanced cardiac MRI (ceMRI) and TIMI myocardial perfusion grade analysis (TMPG) are proven methods for visualization of microinfarction and assessment of microvascular perfusion, respectively. To determine whether microvascular obstruction accounts for procedure-related myonecrosis, 14 poststent patients, 9 with procedural CK-MB elevation and 5 controls, underwent ceMRI and TMPG. All had TIMI 3 flow pre- and poststent. TMPG was normal in 12/14 pre- and 7/14 poststent. Those with poststent decline in TMPG had higher CK-MB (median, 41.0 vs. 7.4 ng/mL; P = 0.01) and larger infarct mass (median, 3.1 vs. 0.89 g; P = 0.04). More extensive myonecrosis (CK-MB > 3 x normal; infarct mass > 3 g) was observed more frequently if there was a poststent decline in TMPG (3/3, 100%, vs. 2/11, 18.2%; P = 0.03). These data support the theory that distal embolization and microvascular obstruction are associated with myonecrosis following otherwise successful coronary stent placement and provide further insight into its pathophysiology.

Endovascular Stenting for Stenoses in Surgically Reconstructed Brachiocephalic Bypass Grafts:Immediate and Midterm Outcomes

PURPOSE

To report the use of endovascular stenting for treatment of patients with symptomatic obstruction of brachiocephalic surgical reconstructions.

METHODS

Twenty-two patients (17 men; mean age 65+/-6 years) with 24 symptomatic obstructions of brachiocephalic Dacron bypass grafts (2 aorto-innominate, 9 subclavian-carotid, and 11 carotid-subclavian) were treated with balloon-expandable stents delivered via a percutaneous brachial access or surgical exposure of the common carotid artery. A distal protection device was utilized in the 9 patients with subclavian-carotid bypass grafts. All patients were followed by clinical and Doppler examinations.

RESULTS

Procedural success was 100%; 1 (4.5%) patient developed transient intraprocedural aphasia owing to intolerance to the distal protection balloon occlusion. All 22 patients reported complete relief of their presenting symptoms. Over a 29-month follow-up, 3 (13.6%) restenoses were found, but none was due to stent compression.

CONCLUSIONS

Stenting for obstructed brachiocephalic reconstructions appears to be a safe, effective, and durable therapeutic strategy.

Distal protection of bifurcating vessels: a novel approach

Distal protection devices protect only a single distal vessel. We describe a novel technique to protect both branches following a thrombus-containing bifurcation lesion. The combination of an occlusive balloon and an arterial filter system provides an attractive solution to the challenging environment of a lesion at high risk for distal embolization supplying more than a single major branch.

Six-month angiographic results of primary angioplasty with adjunctive PercuSurge GuardWire device support: Evaluation of the restenotic rate of the target lesion and the fate of the distal balloon occlusion site

Recently, the combination of primary percutaneous coronary intervention (PCI) and adjunctive PercuSurge device support has been reported to be superior to conventional primary PCI in terms of immediate angiographic results. However, there are no data regarding 6-month angiographic results for either the treatment site or the site of the distal protection balloon. The purpose of this study was to address these two issues. Between May and November 2002, a total of 74 patients who had experienced acute myocardial infarction (AMI) underwent either primary PCI (48 patients within 12 hr of AMI) or elective PCI (26 patients with AMI of > 12 hr and < 72 hr) using the PercuSurge device through a transradial approach. The final TIMI 3 flow and myocardial blush grade > or = 2 achieved were 94% and 93%, respectively. Of these patients, three died in the hospital, two died in the third month after discharge, and the remainder of the patients were followed up in our outpatient department for a mean of 13 +/- 2.9 months. Six-month angiographic follow-up was performed in 85.5% (59/69) of patients. The angiographic restenotic rate (defined as > or = 50% restenosis at the target lesion site) was 22.0% (13/59) of patients. However, only 11.9% (7/59) of patients required repeat target vessel revascularization. Moderate obstruction at the site of the distal protection balloon was found in 5.1% (n = 3) of patients during PCI. Six-month angiographic results demonstrated that all three patients had significant stenosis at the site of the distal protection balloon that required PCI. PercuSurge device utilization during PCI in the clinical setting of AMI yielded a substantially higher rate of immediate final TIMI 3 flow in epicardial vessels and increased the integrity of the microvasculature. Combined therapy of PCI with the PercuSurge device appeared to have favorable late angiographic results at the target site. Late significant stenosis occurred at the site of the distal protection balloon if a preexisting moderate or more advanced atherosclerotic lesion was present there.

Distal Shower Embolization During Directional Coronary Atherectomy and Stenting for Diffuse Stenosis of Right Coronary Artery-Current Limitations of Intravascular Ultrasonography for Evaluating Fragile Plaque-

A 74 year-old male with old anterior and inferior myocardial infarctions was treated with staged percutaneous coronary intervention. A chronic total occlusion of the middle segment of the left anterior descending branch was successfully stented during the first stage, and during the second stage, preprocedural intravascular ultrasonography (IVUS) revealed that the proximal segment of the right coronary artery was diffusely stenosed by mixed plaque. Directional coronary atherectomy under IVUS guidance was performed, but coronary slow flow appeared during the procedure. After successfully bailing out with intracoronary nicorandil, percutaneous thrombectomy and manual blood pumping, 2 coronary stents were implanted to fully cover the lesion. Quite contrary to expectation, the no-reflow phenomenon appeared just after post-dilatation and a repeat of the same maneuver could not completely recover coronary flow. Plaque fragility could not be predicted from the IVUS examination.

Transradial application of percusurge guardwire device during primary percutaneous intervention of infarct-related artery with high-burden thrombus formation

A large infarct-related artery (IRA), which mostly contains high-burden thrombus formation (HBTF) and lipid pool-like plaque contents, has been suggested to play a pivotal role in the no-reflow phenomenon during primary percutaneous coronary intervention (p-PCI). To reduce the thrombus burden of the IRA using the PercuSurge GuardWire device before intervention may be of crucial importance to preventing no-reflow. The purposes of this study were to test the transradial application (TRA) of this new mechanical device and to determine its impact on prevention of no-reflow during p-PCI. From May to September 2002, the PercuSurge GuardWire device was utilized in 42 consecutive patients with acute myocardial infarction and large IRA (vessel size >or= 3.5 mm with HBTF; group 1). From January to December 2000, p-PCI was performed in large IRA (vessel size >or= 3.5 mm) with HBTF using tranfemoral arterial approach in 101 consecutive patients (group 2). The angiographic and clinical outcomes of the two groups were compared in a chronologically consecutive manner. Successful reperfusion (final TIMI-3 flow) was significantly higher in group 1 than in group 2 patients (95.2% vs. 79.1%; P = 0.005). Moreover, the combined incidence of vascular complications, post-PCI thromboembolisms (defined as a distal embolism and a post-PCI residual thrombus score of >or= 3), and combined 30-day major adverse cardiac events were significantly lower in group 1 than in group 2 patients (all P values < 0.05). In group 1 patients, post-p-PCI myocardial blush (MB) of >or= 2 grades was found to be more than 88.0%. Furthermore, when compared with preintervention, thrombus scores were significantly reduced after aspiration (P = 0.0001), whereas the minimal lumen diameter (P = 0.0001), TIMI flow grade (P = 0.0001), and MB grade (P = 0.0001) had all significantly increased after aspiration using Export Aspiration Catheter. There were no significant differences in corrected TIMI frame count (P = 0.42), TIMI flow grade (P > 0.5), or MB grade (all P values > 0.5) between postaspiration and post-PCI. The TRA of the PercuSurge GuardWire device during primary intervention of large IRA with HBTF was safe and feasible and provided benefits to patients. The initial successful reduction of the thrombus burden with this mechanical device before intervention can be translated into increased final TIMI-3 flow, a combined MB of >or= 2 grades, and fewer final thromboembolic events.

Effect of the PercuSurge GuardWire device on the integrity of microvasculature and clinical outcomes during primary transradial coronary intervention in acute myocardial infarction

The present study investigates whether preintervention thrombectomy with a PercuSurge distal balloon protection device can improve final angiographic results compared with adjunctive tirofiban therapy during primary percutaneous coronary intervention (PCI) in large infarct-related arteries (IRAs) (vessel size >/=3.5 mm) with high-burden thrombus formation (HBTF). Results indicate that this mechanical device is superior to adjunctive tirofiban therapy during primary PCI in large IRAs with HBTF in terms of final epicardial flow, microvasculature integrity, and 30-day clinical outcomes.

Comparison of creatine kinase elevation and outcome of comparison of percutaneous coronary intervention for saphenous vein graft in-stent restenosis versus de novo stenosis

Percutaneous coronary intervention of saphenous vein grafts is associated with distal embolization. We aimed to compare potential differences in patients undergoing percutaneous coronary intervention for in-stent restenosis with de novo saphenous vein graft lesions. Myocardial necrosis was associated with higher mortality regardless of lesion type.

Combined distal embolization protection and rheolytic thrombectomy to facilitate percutaneous revascularization of totally occluded saphenous vein grafts

Totally occluded saphenous vein grafts are difficult to treat percutaneously with a higher likelihood of distal embolization and slow-flow or no-reflow during percutaneous interventions. The PercuSurge system, which utilizes a distal balloon occlusive device, has been shown to improve clinical outcomes during saphenous vein graft (SVG) interventions. This device may not be optimal in the setting of heavy thrombus or debris burden, a situation frequently encountered in totally occluded SVGs. Rheolytic thrombectomy facilitates percutaneous interventions by effectively removing intraluminal thrombus and debris but lacks distal embolization protection. We report our experience with the synergistic use of balloon-based distal embolization protection (PercuSurge) and rheolytic thrombectomy (AngioJet) to optimize percutaneous revascularization of totally occluded SVGs.

Distal protection in native coronary arteries during primary angioplasty in acute myocardial infarction: Single-center experience

Distal embolization of plaque or thrombotic debris is one of the mechanisms involved in the ischemia/reperfusion injury during primary percutaneous intervention for acute occlusion of a native coronary artery. We tested the clinical application of maximal antiplatelet therapy with abciximab combined with one of two different systems of mechanical distal protection: balloon occlusion and aspiration (PercuSurge) in 24 cases and a distal filter (FilterWire Ex) in 10 cases. Feasibility, technical limitations, and pitfalls are described.

Results of endovascular treatment of internal carotid artery stenoses with a newly developed balloon protection catheter

OBJECTIVE

A new balloon protection catheter to prevent distal emboli during internal carotid artery percutaneous transluminal angioplasty and stenting was developed, and its efficacy was evaluated in both an experimental model and clinical cases.

METHODS

The balloon protection catheter was navigated over a steerable 0.014-inch guidewire to negotiate tight stenoses and sharp bends, which would cause difficulties for the passage of a flow-directed balloon catheter. Percutaneous transluminal angioplasty and stenting were performed for 85 consecutive patients with 87 stenotic lesions of the cervical internal carotid artery, with two different methods using this protection system. Distal protection was provided only after dilation for the initial 38 lesions (Group I), but the latter 49 lesions were treated in both the pre- and postdilation periods (Group II). The effects of using the balloon protection catheter with the embolic debris clearance technique were evaluated with pre- and postoperative magnetic resonance imaging for each group.

RESULTS

The balloon protection catheter was introduced beyond the stenosis in all cases. In Group I, one symptomatic embolic stroke was caused by distal embolization resulting from atheromatous plaque, and high-intensity areas appeared on diffusion-weighted magnetic resonance imaging scans in 47% of cases. In contrast, in Group II, there were no strokes related to the procedure, although one patient with multiple risk factors died suddenly on the second day after stenting. Diffusion-weighted imaging scans demonstrated small, high-intensity areas in 19% of cases in Group II. The overall morbidity/mortality rate in our series was 2.3%.

CONCLUSION

Our new balloon protection catheter was reliably navigated across internal carotid artery stenoses and reduced distal embolism in clinical cases.

Rapid thrombectomy for treatment of macroembolization during percutaneous coronary intervention in the setting of acute myocardial infarction

We report the use of the Export catheter as an urgent modality to aspirate thrombus that embolized down the left anterior descending artery during acute myocardial infarction.

Coronary microembolization

Atherosclerotic plaque rupture is a key event in the pathogenesis of acute coronary syndromes and during coronary interventions. However, it does not always result in complete thrombotic occlusion of the entire epicardial coronary artery with subsequent acute myocardial infarction; in milder forms the result can be embolization of atherosclerotic and thrombotic debris into the coronary microcirculation. This review summarizes the available morphological evidence for coronary microembolization in patients who died from coronary artery disease, most notably from sudden death, and then goes on to address the experimental pathophysiology of coronary microembolization in animal models of acute coronary syndromes and heart failure. Finally, the review presents the available clinical evidence for coronary microembolization in patients, highlights its key features (ie, arrhythmias, contractile dysfunction, infarctlets and reduced coronary reserve) and addresses its prevention by mechanical protection devices and glycoprotein IIb/IIIa antagonism.

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.

Preliminary experiences using X-sizer catheter for mechanical thrombectomy of thrombus-containing lesions during acute coronary syndromes

Thrombus-containing lesions are frequently observed in patients with acute coronary syndromes. These lesions are prone to increased procedural risks, including distal embolization and abrupt closure of the vessel. This preliminary report evaluates if thrombus removal using a new X-Sizer catheter could reduce thrombotic burden and optimize angioplasty results. Thrombectomy was attempted with the X-Sizer catheter in 11 patients (age, 59 +/- 10 years) undergoing coronary angioplasty with angiographic evidence of intracoronary thrombus. The device uses a helix cutter contained in a 4.5 or 5.5 Fr catheter tip connected to a closed vacuum aspiration system. Procedural outcomes using detailed angiographic analysis and clinical data were obtained from all treated patients. Seven patients (64%) had acute or recent myocardial infarction and four patients (36%) presented with unstable angina. The culprit lesion was located in right coronary, left anterior, vein graft, and circumflex-marginal in five, three, two, and one patient, respectively. The mean proximal reference diameter was 3.37 +/- 0.39 mm and % diameter stenosis was 90% +/- 15% prior to thrombectomy and decreased to 72% +/- 16% afterward and was 9% +/- 10% at the end of the procedure. The TIMI flow increased from 0.8 +/- 1.0 to 2.1 +/- 0.9 following thrombectomy and the final TIMI grade was 2.9 +/- 0.3. Stents were used in 9 of 11 patients. Procedural success was achieved in 10 of 11 patients (91%). No evidence of stent thrombosis was noted among treated patients in hospital and at 30-day follow-up. In this preliminary series of patients with angiographic evidence of thrombus, the use of X-Sizer thrombectomy seems to be feasible and relatively safe, permitting thrombus removal and improved intracoronary flow.

Use of filterwire EX for distal embolic protection during complex percutaneous coronary interventions: four case studies

We describe four successful cases demonstrating the use of a novel filter-guidewire (FilterWire EX) during complex percutaneous coronary interventions in saphenous vein grafts (n = 3) and native coronary artery (n = 1) for prevention of distal embolization and consequently myonecrosis.

[Angiographic results of thrombectomy performed with two new devices in lesions with intracoronary thrombus]

INTRODUCTION AND OBJECTIVE

The presence of intracoronary thrombus is associated with less favorable results of percutaneous coronary interventions. In recent years, new devices have been designed to improve the outcome of these procedures when an intracoronary thrombus is present. The results of two new systems of thrombectomy used in a single center are analyzed.

METHODS

Prospective observational registry of the use of two thrombectomy devices, X-SIZER (EndiCOR Medical Inc., San Clemente, California, USA) and RESCUE (Boston Scientific Scimed, Inc., Maple Grove, Minnesota, USA), between 1 June 2000 and 15 February 2002. RESULTS. One hundred thirty-nine devices were used in 137 patients (112 RESCUE and 27 X-SIZER). The main indication was primary angioplasty for acute myocardial infarction (80%). In 7 patients (5%), unscheduled thrombectomy was performed for unexpected complications that appeared during the procedure. In 75% of patients, IIb/IIIa inhibitors were given. In 10 cases (7%) the device did not reach the lesion. Complications derived from the use of the device were recorded in 3 cases (2.1%). TIMI flow improved from 1.28 1.1 before thrombectomy to 2.31 1.2 after the procedure. Improvement in the thrombus image was observed in 86%. The intervention was successful in 86%.

CONCLUSIONS

Thrombectomy with X-Sizer and Rescue improved the angiographic thrombus image in most cases and was associated to a low complication rate. Its efficacy compared to the conventional technique should be assessed in future trials.

Export aspiration catheter thrombosuction before actual angioplasty in primary coronary intervention for acute myocardial infarction

Primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in lesions with a large thrombus load increases the procedural complication rate. We describe a thrombus reduction technique in this setting using the Export aspiration catheter (EAC) for primary thrombosuction before actual angioplasty. The EAC is a component of the GuardWire Plus system (PercuSurge, Sunnyvale, CA), which was originally developed for emboli containment in saphenous vein graft and peripheral vessel interventions. Primary EAC thrombosuction was performed successfully in 12 patients undergoing primary PCI, and gross thrombi were obtained from 9 patients (75%). After definitive treatment with balloon angioplasty and/or stenting, TIMI 3 flow was restored in all target vessels. There was no angiographic evidence of distal branch loss or vessel injury. No major procedural or in-hospital complication occurred in any patients. This primary EAC thrombosuction technique may offer a new, potentially effective method for thrombus burden reduction in treating AMI patients.

Resolution of refractory no-reflow with intracoronary epinephrine

Refractory no-reflow is associated with adverse outcomes in patients undergoing percutaneous coronary intervention. Charts were reviewed to identify 29 consecutive patients in whom intracoronary epinephrine was administered for refractory no-reflow. The effects of intracoronary epinephrine on coronary flow (TIMI grade), cardiac rhythm, and systolic blood pressure in the cardiac catheterization laboratory were assessed. Administration of intracoronary epinephrine (mean dose, 139 +/- 189 microg) resulted in significant improvement in coronary flow. After administration, TIMI 3 flow was established in 69% of patients. Overall, TIMI flow significantly increased (mean TIMI flow form 1.0 +/- 1.0 to 2.66 +/- 0.55; P = 0.0001). Intracoronary epinephrine resulted in significant but tolerable increase in heart rate (72 +/- 19 to 86 +/- 26 beats/min; P = 0.009), but no cases of acute dysrhythmia. These findings indicate that intracoronary epinephrine may exert salutary effects in patients suffering refractory no-reflow following elective or acute coronary interventions.

Treatment of totally occluded saphenous vein grafts using self-expanding stents

Patients with saphenous vein graft (SVG) disease represent an increasing proportion of those referred for percutaneous coronary intervention. The success of treatment of occluded SVG with percutaneous intervention has been limited by frequent occurrence of no-reflow phenomenon. Use of self-expanding stents with low pressure pre- and post-dilation may improve success by limiting embolism of atherothrombotic debris. The self-expanding stents provide a meshed design that helps to trap the atherothrombotic debris between the vessel wall and stent struts. Results with two patients are described to illustrate the proposed technique that appears to limit no-reflow during and immediately after the procedure. Adjunctive treatment with a GP IIb-IIIa inhibitor is likely to be of benefit as well. Additional studies are required to demonstrate definitively the potential benefits of this approach.

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.