Use Of Distal Protection Devices Research Articles

The role of intracoronary thrombolysis in selected patients presenting with ST-elevation myocardial infarction: a case series.

BackgroundPrimary percutaneous coronary intervention (PCI) is the cornerstone of management for ST-elevation myocardial infarction (STEMI). However, large intracoronary thrombus burden complicates up to 70% of STEMI cases. Adjunct therapies described to address intracoronary thrombus include manual and mechanical thrombectomy, use of distal protection device and intracoronary anti-thrombotic therapies.Case summaryThis series demonstrates the use of intracoronary thrombolysis in the setting of large coronary thrombus, bifurcation lesions with vessel size mismatch, diffuse thrombosis without underlying plaque rupture, and improving coronary flow to allow vessel wiring and proceeding to definitive revascularization.DiscussionLarger intracoronary thrombus burden correlates with greater infarct size, distal embolization, and the associated no-reflow phenomena, and propagates stent thrombosis, with subsequent increase in mortality and major adverse cardiac events. Intracoronary thrombolysis may provide useful adjunct therapy in highly selected STEMI cases to reduce intracoronary thrombus and facilitate revascularization.

Impact of Distal Protection with Filter-Type Device on Long-term Outcome after Percutaneous Coronary Intervention for Acute Myocardial Infarction: Clinical Results with Filtrap®.

Aim: Although distal embolization during percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) deteriorates cardiac function, whether distal protection (DP) can improve prognosis is still controversial. We investigated whether a filter-type DP device, Filtrap®, could improve long-term outcomes after PCI for AMI.Method: We studied 164 patients (130 men, mean age: 65.7 years) who underwent PCI. Patients were divided into two groups based on the use of Filtrap®. The occurrence of congestive heart failure (CHF) and major adverse cardiac events (MACE) defined as cardiac death, recurrent AMI, and target vessel revascularization were compared.Result: Between DP (n = 53, 41 men, mean age: 65.5 years) and non-DP (n = 111, 89 men, mean age: 65.8 years) groups, although there was significantly greater plaque area in the DP group than in the non-DP group, there were no significant differences in coronary reperfusion flow after PCI. Interestingly, patients with CHF in the non-DP group exhibited a higher CK level than those in the DP group. During a 2-year follow-up period, cumulative CHF was significantly lower in the DP group than in the non-DP group (log-rank p = 0.018), and there was no significant difference in the MACE rate (log-rank p = 0.238). The use of DP device could not predict MACE, but could predict CHF by multivariate analysis (odds ratio = 0.099, 95% CI: 0.02–0.42, p = 0.005).Conclusion: These results demonstrate that favorable clinical outcomes could be achieved by the filter-type DP device in AMI, particularly in patients with CHF.

Results of the Retrospective Analysis of Renal Artery Stenting for the Salvage of Renal Function Study

Renal artery stenting is expected to improve or stabilize renal function. However, the efficacy of renal artery stenting in severely reduced renal function is unclear. We evaluated 23 patients with class IV or V renal dysfunction who were treated for renal artery stenosis between 2004 and 2009. Improvement in renal function was found in 7 (30%) patients, all of whom were treated with distal protection device. Deterioration of renal function was found in 4 (17%) cases. In these 4 cases, distal protection device could not be used for anatomical reasons. The use of distal protection device was associated with significantly less renal deterioration after the procedure (P < .05, odds ratio 0.21 [confidence interval 0.09-0.50]). Renal artery stenting can stabilize or improve renal function in patients with severe renal dysfunction. Distal protection devices may be beneficial in patients who require renal artery stenting due to severely reduced renal function.

Simultaneous Bilateral Carotid Stenting in a Series of 9 Patients: A Single-Center Experience with Review of Literature

Objectives:Simultaneous bilateral carotid artery stenting (SBCAS) is a challenging procedure, and selection criteria play an important role in determining the final outcome. The aim of the present study was to determine the efficacy and safety of the SBCAS in a series of 9 patients with significant bilateral carotid artery disease (>50% on the symptomatic side and >60% on the asymptomatic side).Materials and Methods:The present study is a retrospective study of 9 patients from January 2005 to December 2012 in a tertiary care center. There were 8 males and 1 female in the age range 50 to 75 years and an average mean age of 63 years. Inclusion criteria of the present study were patients with bilateral internal carotid artery stenosis >50% (50 - 99%) in the symptomatic side and >60% in the asymptomatic side as seen on digital subtraction angiography (DSA). SBCAS with use of distal protection device (Spider device, ev3), to prevent intra-procedural embolic migration, was done in all the patients.Results:Technical success was achieved in all patients (100%). Post-procedural events in the form of hypotension and bradycardia occurred in 3 patients after the placement of stent on both the sides, in 2 patients after the placement of the first stent, and in 1 patient after the placement of the second stent. We did not encounter any cases of hyperperfusion, which was a concern in these patients. There were no deaths, major or minor strokes, or myocardial infarction either in the post-procedural period (up to 1 month) or on clinical follow-up 3 and 6 months post-treatment.Conclusion:SBCAS was an effective and safe alternative treatment method in a select group of patients with bilateral carotid artery disease. It can be considered as a feasible treatment option with acceptable risks.

Immediate evidence of the benefit of distal protection in vein graft intervention

Percutaneous intervention carries a higher risk of distal embolization and fatal outcome in saphenous vein grafts (SVG) than in native coronary vessels. Most of these adverse clinical events, predominantly myocardial infarction and reduced antegrade flow (no reflow phenomenon), are due to distal embolization of atherothrombotic debris and distal microvascular occlusion. For this reason, in current interventional practice, the use of distal protection devices is mandatory. Our case report provides direct and dramatic evidence of the usefulness of a low-profile filter device in the setting of massively thrombotic SVG.

037 Drug eluting stents (DES) offer benefit over bare metal stents (BMS) inserted during vein graft PCI

BackgroundResearch trials have shown improved short-term outcome with DES over BMS in Saphenous vein graft (SVG) PCI, primarily by reducing target vessel revascularisation (TVR) for in-Stent Restenosis (ISR). Because of...

Distal protection devices in primary percutaneous coronary intervention of native coronary artery lesions: a meta-analysis of randomized controlled trials

Objective:The use of embolic protection devices to decrease major adverse cardiac events (MACEs) in patients with saphenous vein graft lesions is considered class I therapy by the recent practice guidelines. However, the benefits of adjunctive protection devices to prevent distal embolization in patients with native coronary artery lesions are still a matter of debate. Therefore, we performed the meta-analysis to determine whether the use of distal protection devices during revascularization can improve myocardial perfusion and reduce the occurrence of MACEs compared with primary percutaneous coronary intervention (PCI) alone.Methods and results:Studies were identified in English-language articles by search of Medline and Embase database (inception to December 2011). A total of 15 prospective randomized controlled trials involving 2783 patients were included for analysis (1378 patients in the distal protection device group and 1405 cases in the control group). Overall, adjunctive embolic protection was associated with significantly improved postprocedural TIMI 3 (thrombolysis in myocardial infarction 3) flow (OR 1.71; 95% CI 1.13–2.57; P = 0.01) and MBG 3 (myocardial blush grade 3) (OR 1.50; 95% CI 1.09–2.07; P = 0.01), whereas the overall MACEs analysis demonstrated that a nonsignificant trend was observed toward better clinical outcomes associated with adjunctive protection devices at 1 month (OR 0.80; 95% CI 0.55–1.15; P = 0.23) and at 6 months (OR 0.80; 95% CI 0.55–1.17; P = 0.24). When stratified by MACEs, no statistical differences were found among mortality, reinfarction, and target vessel revascularization (TVR), respectively.Conclusions:The meta-analysis indicated an improvement of myocardial perfusion in AMI patients treated with adjunctive protection devices. However, a nonsignificant trend was observed toward a lower risk of MACEs in the distal protection device group when compared with the control group.

Carotid Angioplasty and Stenting Without Protection Devices

Against the background of the increasing dilemma in the scientific community regarding protected versus unprotected carotid artery stent (CAS) placement and the disputed points in interpreting the results of scientific studies as well as the difficulty in conducting such randomized controlled studies, this article gives a review of experiences with carotid stent placement without the use of protection devices. This series comprised 133 consecutive patients with 136 carotid stenoses of which 128 carotid arteries (94%) were either symptomatic (93 out of 136 = 68.4%) or had a greater than 70% stenosis (35 out of 136 = 25.7%) and 8 out of 136 were asymptomatic and had stenoses between 50% and 70%. Patients underwent neurologic and sonographic evaluation before the procedure and during follow-up (mean 18 months). Primary stent placement was carried out in 110 out of 136 lesions and predilatation was necessary before stent deployment in 26 lesions,. Neurologic periprocedural complications included 3 disabling and 1 non-disabling strokes. During the follow-up period there were 6 deaths all unrelated to the carotid disease and no major strokes. The degree of stenosis decreased from a mean of 81% to a mean of 12.3% immediately after the procedure, 22 patients were defined as restenosis of which 9 were symptomatic. Carotid stent placement without the use of distal protection devices was found to be a safe and effective procedure with a relatively low incidence of periprocedural complications.

Guidelines for patient selection and performance of carotid artery stenting

The endovascular treatment of carotid atherosclerosis with carotid artery stenting (CAS) remains controversial. Carotid endarterectomy remains the benchmark in terms of procedural mortality and morbidity. At present, there are no consensus Australasian guidelines for the safe performance of CAS. We applied a modified Delphi consensus method of iterative consultation between the College representatives on the Carotid Stenting Guidelines Committee (CSGC). Selection of patients suitable for CAS needs careful consideration of clinical and patho-anatomical criteria and cannot be directly extrapolated from clinical indicators for carotid endarterectomy (CEA). Randomized controlled trials (including pooled analyses of results) comparing CAS with CEA for treatment of symptomatic stenosis have demonstrated that CAS is more hazardous than CEA. On current evidence, the CGSC therefore recommends that CAS should not be performed in the majority of patients requiring carotid revascularisation. The evidence for CAS in patients with symptomatic severe carotid stenosis who are considered medically high risk is weak, and there is currently no evidence to support CAS as a treatment for asymptomatic carotid stenosis. The use of distal protection devices during CAS remains controversial with increased risk of clinically silent stroke. The knowledge requirements for the safe performance of CAS include an understanding of the evidence base from randomized controlled trials, carotid and aortic arch anatomy and pathology, clinical stroke syndromes, the differing treatment options for stroke and carotid atherosclerosis, and recognition and management of periprocedural complications. It is critical that all patients being considered for a carotid intervention have adequate pre-procedural neuro-imaging and an independent, standardized neurological assessment before and after the procedure. Maintenance of proficiency in CAS requires active involvement in surgical/endovascular audit and continuing medical education programs. These standards should apply in the public and private health care settings. These guidelines represent the consensus of an inter-collegiate committee in order to direct appropriate patient selection and the range of cognitive and technical requirements to perform CAS. Advances in endovascular technologies and the results of randomized controlled trials will guide future revisions of these guidelines.

Guidelines for patient selection and performance of carotid artery stenting

The endovascular treatment of carotid atherosclerosis with carotid artery stenting (CAS) remains controversial. Carotid endarterectomy (CEA) remains the benchmark in terms of procedural mortality and morbidity. Consensus Australasian guidelines for the safe performance of CAS were developed using the modified Delphi consensus method of iterative consultation. Selection of patients suitable for CAS needs careful consideration of clinical and patho-anatomical criteria. Randomised controlled trials and pooled analyses have demonstrated that CAS is more hazardous than CEA. The CGSC therefore recommends that CAS should not be performed in the majority of patients requiring carotid revascularisation. There is currently no evidence to support CAS as a treatment for asymptomatic carotid stenosis. The use of distal protection devices during CAS remains controversial with increased risk of clinically silent stroke. The knowledge requirements for the safe performance of CAS include an understanding of the evidence base from randomised controlled trials, carotid and aortic arch anatomy and pathology, and recognition and management of periprocedural complications. It is critical that all patients being considered for a carotid intervention have adequate pre-procedural neuroimaging and peri-procedural, independent, neurological assessment. Maintenance of proficiency in CAS requires active involvement in surgical/endovascular audit and continuing medical education programmes. These standards should apply in the public and private health-care settings. These guidelines represent the consensus of an intercollegiate committee in order to direct appropriate patient selection to perform CAS. Advances in endovascular technologies and the results of randomised controlled trials will guide future revisions of this document.

Distal protection beneficial?

The pathogenesis of acute coronary syndromes (ACS) includes the rupture or erosion of a coronary atherosclerotic plaque with variable degrees of superimposed platelet aggregation inducing a thrombus [1]. ST-elevation myocardial infarction (STEMI) is often caused by a total coronary occlusion of the atherothrombotic plaque, whereas in non-ST-elevation myocardial infarction (NSTEMI) the thrombus is mainly nonocclusive or transient occlusive causing less myocardial damage [2]. Conventional percutaneous coronary intervention (PCI) focuses on compressing the atherothrombotic plaque with the aim to normalize flow in the coronary artery and therefore restore perfusion of the ischemic myocardium [3]. However, embolization of atherothrombotic material may occur spontaneously after plaque rupture or due to mechanical crushing of the culprit lesion during PCI [4]. This results in obstruction of distal vessels or the microcirculation in the down-stream bed of the ischemia-related artery. Although normal epicardial flow may be achieved, this will lead to diminished myocardial perfusion, which is associated with larger infarct size, diminished left ventricular ejection fraction and increased mortality [5]. Microvascular obstruction is frequently implicated as the underlying cause through the mechanism of embolization [6–8]. Distal protection devices (DPDs) can be used for transient distal balloon occlusion during PCI, and allow recovery of any liberated plaque by aspiration before restoration of the antegrade flow [9]. Whether myocardial function can be improved with DPDs compared with conventional PCI in patients with acute myocardial infarction (AMI) has still to be proven. Over the years, echocardiography [10–13] and CMR [14–37] have found a fixed niche in the setting of AMI. In particular CMR allows the visualization of infarct site and size whereby the identification of microvascular obstruction has become unique to CMR [38–40]. For echocardiography, there are limited data describing changes in cardiac function in DPDs studies, and no data describing changes in regional myocardial function. Tissue Doppler imaging (TDI) is a useful echocardiographic tool that permits quantitative and objective assessment of both global and regional function [41–43]. In the current issue of the International Journal of Cardiovascular Imaging, Duan et al. [44] assessed the effects of DPDs on global and regional LV systolic and diastolic function were assessed by TDI in 69 patients with anterior AMI, who were randomly assigned to either PCI with DPDs (DPD group, n = 46) or conventional PCI (control group, n = 50). At 3- and 6-month follow-up, the DPD group showed a higher LV ejection fraction than the control group. Moreover, peak systolic and early diastolic mitral annular velocities obtained by TDI were significantly higher in the DPD group than in the control group. Lastly, the systolic and diastolic regional myocardial velocities were significantly improved in the DPD group compared to the control group. The authors concluded that patients with DPDs showed significant improvement of LV function. Especially patients with anterior AMI may benefit from DPDs during PCI. In recent years various distal protection devices and thrombectomy devices have been developed to protect the microcirculation against embolization of atherothrombotic material and to improve myocardial reperfusion and LV function after PCI [45]. As the use of distal protection devices is still under debate, several trials in patients with STEMI have recently focused on thrombus aspiration [46–49]. These trials have clearly shown that thrombus aspiration improves myocardial reperfusion compared to conventional PCI. The largest study to date, the TAPAS-trial, showed that manual thrombus aspiration using the Export Aspiration Catheter (EAC) in patients with STEMI improves myocardial perfusion and one-year clinical outcome compared to conventional PCI [47]. As a consequence, thrombus aspiration has been included in the new European guidelines for patients with STEMI as a therapy to improve myocardial perfusion [50]. To conclude, the study of Duan et al. [44] lends support to the notion that distal protection may be beneficial in patients with STEMI.

Outcome of Undersized Drug-Eluting Stents for Percutaneous Coronary Intervention of Saphenous Vein Graft Lesions

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

COGNITIVE OUTCOMES AFTER CAROTID REVASCULARIZATION

Abstract OBJECTIVE Carotid artery stenting (CAS) and carotid endarterectomy (CEA) are currently being compared in ongoing randomized, controlled trials using postprocedural 30-day stroke rate, myocardial infarction, and mortality as primary endpoints. Recent data suggest that cognitive function may decline after CEA. Understanding the mechanisms that affect cognitive outcomes after carotid revascularization will be important in the design of future comparative studies of CAS and CEA incorporating cognitive outcome as an endpoint. SUMMARY OF REVIEW The effects of carotid revascularization procedures on cognitive outcome are unclear. Several factors contribute to the difficulty in interpreting cognitive data, including patient heterogeneity, variability of surgical techniques, and the differences in neuropsychological testing methodology. Mechanisms underlying cognitive effects during CEA have emerged, including the potential detrimental effect of procedural emboli and the beneficial effect of improved cerebral hemodynamics. The emergence of CAS as an alternative to CEA for treating carotid stenosis again raises questions about cognitive outcomes. Despite the use of distal protection devices, CAS is associated with a higher burden of microemboli. CAS does not, however, require the extent of temporary vessel occlusion associated with CEA. Quantifying microemboli and changes in cerebral hemodynamics along with standardization of neuropsychological testing may lead to meaningful comparisons of cognitive data for patients undergoing carotid revascularization procedures. CONCLUSION As use of CAS increases, it is important for randomized, controlled trials comparing CAS with CEA to include cognitive outcomes assessments. Furthermore, understanding the key mechanisms resulting in cognitive impairment during carotid revascularization procedures might limit injury.

Flow Impairment During Saphenous Vein Graft Intervention is Associated With Greater Plaque Embolization Despite Use of Distal Protection Device

Backgroundandaims:Saphenousveingraft percutaneous coronary intervention (SVG-PCI) has a 10–30% risk of myocardial infarction (AMI) by the ‘slow or no-reflow’ phenomenon. This is partly mediated by the embolization of atheromatous material. We sought to identify factors associated with reduced flow as assessed by TIMI frame count (TFC) post SVG-PCI. Methods: Consecutive patients (n= 24, age 68± 9) undergoing SVG-PCI utilizing the distal protection device, FilterWire EZ (Boston Scientific, Natick, MA) were enrolled. Quantitative coronary analysis (QCA) and TFC were performed on all angiograms by two cardiologists. We evaluated patients in two groups defined as improved or impaired TFC post-procedure. Results:Themean age of SVGwas 14.4 (±4.4) years. A total of 26 lesions were analysed with a mean lesion length of 23.3 (±17.9) mm. The inter-observer variability in TFCwas 2.3%. Increased TFC post-PCI, a marker of reduced flow, w a p r s t F l g C u i fl s b

Distal Embolic Protection for Renal Arterial Interventions

Distal or embolic protection has intuitive appeal for its potential to prevent embolization of materials generated during interventional procedures. Distal protection devices (DPDs) have been most widely used in the coronary and carotid vascular beds, where they have demonstrated the ability to trap embolic materials and, in some cases, to reduce complications. Given the frequency of chronic kidney disease in patients with renal artery stenosis undergoing stent placement, it is reasonable to propose that these devices may play an important role in limiting distal embolization in the renal vasculature. Careful review of the literature reveals that atheroembolization does occur during renal arterial interventions, although it often goes undetected. Early experience with DPDs in the renal arteries in patients with suitable anatomy suggests retrieval of embolic materials in approximately 71% of cases and renal functional improvement/stabilization in 98% of cases. The combination of platelet inhibition and a DPD may provide even greater benefit. Given the critical importance of renal functional preservation, it follows that everything that can be done to prevent atheroembolism should be undertaken including the use of DPDs when anatomically feasible. The data available at this time support a beneficial role for these devices.

Comparison of Myocardial Reperfusion in Patients Undergoing Percutaneous Coronary Intervention in ST-Segment Elevation Acute Myocardial Infarction With Versus Without Diabetes Mellitus (from the EMERALD Trial)

Diabetes mellitus is strongly associated with increased cardiovascular morbidity and mortality in patients with ST-segment elevation myocardial infarction. It is unknown whether myocardial perfusion is decreased in diabetic compared with nondiabetic patients after primary percutaneous coronary intervention (PCI), which may contribute to their worse prognosis. We compared myocardial perfusion and infarct sizes between diabetic and nondiabetic patients undergoing PCI for acute ST-segment elevation myocardial infarction in the EMERALD trial. EMERALD was a prospective, randomized, multicenter study evaluating distal embolic protection during primary PCI in ST-segment elevation myocardial infarction. End points included final myocardial blush grade, complete ST-segment resolution (STR) 30 minutes after PCI, and final infarct size as determined by technetium-99m single proton emission computed tomography measured between days 5 and 14. Of 501 patients, 62 (12%) had diabetes mellitus. Diabetic patients had impaired myocardial perfusion after PCI as measured by myocardial blush grade 0/1 (34% vs 16%, p = 0.002) and lower rates of complete 30-minute STR (45% vs 65%, p = 0.005). Infarct size (median 20% vs 11%, p = 0.005), development of new onset severe congestive heart failure (12% vs 4%, p = 0.016), and 30-day mortality (10% vs 1%, p <0.0001) were also greater in diabetic patients. After multivariate adjustment, diabetes remained associated with lack of complete STR and mortality at 6 months. Use of distal protection devices did not improve outcomes in diabetic or nondiabetic patients. In conclusion, in patients with ST-segment elevation myocardial infarction undergoing primary PCI, diabetes is independently associated with decreased myocardial reperfusion, larger infarct, development of congestive heart failure, and decreased survival.

MDCT Angiography of the Renal Arteries in Patients with Atherosclerotic Renal Artery Stenosis: Implications for Renal Artery Stenting with Distal Protection

Use of distal protection in renal artery stenting entails overcoming challenges unique to renal artery anatomy. We used 3D image reconstruction to review high-spatial-resolution MDCT angiographic data to better characterize the anatomy of stenotic renal arteries. A total of 218 abdominal MDCT angiograms from a single tertiary care referral center were reviewed. The subjects were 108 patients who had 127 arteries with more than 50% ostial atherosclerotic renal artery stenosis. Vessel analysis software was used to measure renal artery length, cross-sectional area, and maximum diameter. Differences between mean values for women and men and for left and right renal arteries were measured with a two-tailed Student's t test. Significant differences for men and women were found in average maximum cross-sectional area distal to the point of stenosis (0.3 +/- 0.19 vs 0.23 +/- 0.09 cm2, p = 0.006) and the corresponding maximum diameter (6.9 +/- 1.7 vs 6.1 +/- 1.1 cm2, p = 0.003). Average lengths of the main renal artery did not differ significantly for men and women. Differences for the left and right main renal arteries were found in minimum area (i.e., area of maximum stenosis, 0.08 +/- 0.04 vs 0.06 +/- 0.03 cm2, p = 0.03), area proximal to the bifurcation (0.26 +/- 0.11 cm2 vs 0.23 +/- 0.07 cm2, p = 0.02), and length (38.5 +/- 12.6 vs 48.7 +/- 16.2 mm, p = 0.0002). Significant anatomic differences exist between the left and right renal arteries, between the renal arteries in men and those in women, and from one person to the next. Many of these differences are relevant to the design and use of distal protection devices in stenting of the renal arteries.

Carotid Angioplasty and Stent Placement after EVA-3S Trial

Marc Fisher MD Kennedy Lees MD Section Editors A clinical trial is an endeavor where every attempt is made to optimize the quality and quantity of learning before venturing into the unknown”.1 Recently, the Endarterectomy versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis (EVA-3S) trial2 investigators reported the results of a multicenter, randomized, noninferiority trial comparing stent placement with endarterectomy in patients with symptomatic carotid stenosis of ≥60%. Patients were eligible if they experienced a hemispheric or retinal transient ischemic attack or a nondisabling stroke (or retinal infarct) within 120 days before enrollment. Endarterectomy or stent placement was to be performed within 2 weeks after randomization. The primary end point was the occurrence of any stroke or death within 30 days after treatment. The trial started recruiting in November 2000. In January 2003, the safety committee recommended mandatory use of distal protection devices because of a higher risk of stroke in patients treated without distal protection. Although initially recruiting patients with stenosis of ≥70%, the trial started recruiting patients with stenosis of ≥60% in October 2003. In September 2005, the safety committee recommended stopping enrollment after 527 patients (intended target recruitment of 872 patients) had been randomized. On the basis of the observed 30-day risk of stroke or death after endarterectomy, >4000 patients were required to test the noninferiority of stent placement. Given the observed 30-day risks of stent placement, the committee considered it to be extremely unlikely that the trial would reach its objectives despite further enrollment. The 30-day incidence of any stroke or death was 3.9% after endarterectomy and 9.6% after stent placement. The rate of disabling stroke or death was 1.5% after endarterectomy and 3.4% after stent placement. At 6 months, the incidence of any stroke or death was 6.1% after endarterectomy and 11.7% …

Distal Embolization After Stenting of the Vertebral Artery: Diffusion-Weighted Magnetic Resonance Imaging Findings

We retrospectively evaluated our experience with stenting of the vertebral artery in an effort to determine the risk of distal embolization associated with the procedure. Between June 2000 and May 2005, 35 patients with 38 stenting procedures for atherosclerotic disease of the vertebral origin in our institution were identified. The average age of the patients was 60.3 years (range 32-76 years). Sixteen of these patients (with 18 stents) had MR imaging of the brain with diffusion-weighted imaging and an apparent diffusion coefficient map within 2 days before and after procedure. On seven of the 16 postprocedural diffusion-weighted MR images, a total of 57 new hyperintensities were visible. All these lesions were focal in nature. One patient demonstrated a new diffusion-weighted imaging abnormality in the anterior circulation without MR evidence of posterior circulation ischemia. Six of 16 patients had a total of 25 new lesions in the vertebrobasilar circulation in postprocedural diffusion-weighted MR images. One patient in this group was excluded from the final analysis because the procedure was complicated by basilar rupture during tandem stent deployment in the basilar artery. Hence, new diffusion-weighted imaging abnormalities were noted in the vertebrobasilar territory in 5 of 15 patients after 17 stenting procedures, giving a 29% rate of diffusion-weighted imaging abnormalities per procedure. No patient with bilateral stenting had new diffusion-weighted imaging abnormalities. Stenting of stenoses of the vertebral artery origin may be associated with a significant risk of asymptomatic distal embolization. Angiography, placement of the guiding catheter, inflation of the stent balloon, and crossing the lesion with guidewires or balloon catheters may potentially cause distal embolization. Further studies to evaluate measures to increase the safety of vertebral artery stenting, such as the use of distal protection devices or short-term postprocedural anticoagulation, should be considered for patients with clear indications for this procedure.

Particulate debris collected during carotid stenting: Are we missing something?

Particulate and histopathologic examination of atherosclerotic material collected during carotid artery stenting is presented, illustrating the limitations of current knowledge regarding the use of distal protection devices (DPD) during this novel vascular intervention.