Trevor J. Cleveland

Multicenter evaluation of carotid artery stenting with a filter protection system

OBJECTIVES The aim of this study was to evaluate the feasibility and safety of carotid artery stenting (CAS) with a filter protection system. BACKGROUND Neurologic events linked to the embolization of particulate matter to the cerebral circulation may complicate CAS. Strategies designed to capture embolic particles during carotid intervention are being evaluated for their efficacy in reducing the risk of these events. METHODS Between September 1999 and July 2001, a total of 162 patients (164 hemispheres) underwent CAS with filter protection (NeuroShield, MedNova Ltd., Galway, Ireland) according to prospective protocols evaluating the filter system at three institutions. RESULTS Angiographic success was achieved in 162 of the procedures (99%) and filter placement was successful in 154 (94%) procedures. Carotid access was unsuccessful in two cases (1%) and filter placement in eight cases (5%). Of the latter, five procedures were completed with no protection and three were completed using alternative protection devices. On an intention-to-treat basis, the overall combined 30-day rate of all-stroke and death was 2% (four events: two minor strokes and two deaths). This includes one minor stroke in a patient with failed filter placement and CAS completed without protection. There was one cardiac arrhythmic death and one death from hyperperfusion-related intracerebral hemorrhage. There were no major embolic strokes. CONCLUSIONS Carotid artery stenting with filter protection is technically feasible and safe. Early clinical outcomes appear to be favorable and need to be confirmed in a larger comparative study.

Long-term outcomes after stenting versus endarterectomy for treatment of symptomatic carotid stenosis : the International Carotid Stenting Study (ICSS) randomised trial

Summary Background Stenting is an alternative to endarterectomy for treatment of carotid artery stenosis, but long-term efficacy is uncertain. We report long-term data from the randomised International Carotid Stenting Study comparison of these treatments. Methods Patients with symptomatic carotid stenosis were randomly assigned 1:1 to open treatment with stenting or endarterectomy at 50 centres worldwide. Randomisation was computer generated centrally and allocated by telephone call or fax. Major outcomes were assessed by an independent endpoint committee unaware of treatment assignment. The primary endpoint was fatal or disabling stroke in any territory after randomisation to the end of follow-up. Analysis was by intention to treat ([ITT] all patients) and per protocol from 31 days after treatment (all patients in whom assigned treatment was completed). Functional ability was rated with the modified Rankin scale. This study is registered, number ISRCTN25337470. Findings 1713 patients were assigned to stenting (n=855) or endarterectomy (n=858) and followed up for a median of 4·2 years (IQR 3·0–5·2, maximum 10·0). Three patients withdrew immediately and, therefore, the ITT population comprised 1710 patients. The number of fatal or disabling strokes (52 vs 49) and cumulative 5-year risk did not differ significantly between the stenting and endarterectomy groups (6·4% vs 6·5%; hazard ratio [HR] 1·06, 95% CI 0·72–1·57, p=0·77). Any stroke was more frequent in the stenting group than in the endarterectomy group (119 vs 72 events; ITT population, 5-year cumulative risk 15·2% vs 9·4%, HR 1·71, 95% CI 1·28–2·30, p<0·001; per-protocol population, 5-year cumulative risk 8·9% vs 5·8%, 1·53, 1·02–2·31, p=0·04), but were mainly non-disabling strokes. The distribution of modified Rankin scale scores at 1 year, 5 years, or final follow-up did not differ significantly between treatment groups. Interpretation Long-term functional outcome and risk of fatal or disabling stroke are similar for stenting and endarterectomy for symptomatic carotid stenosis. Funding Medical Research Council, Stroke Association, Sanofi-Synthélabo, European Union.

Filter-Protected versus Unprotected Carotid Artery Stenting: A Randomised Trial

Background: Our aim was to determine whether filter protection reduces embolisation to the brain during carotid artery stenting (CAS). Methods: Thirty patients with symptomatic carotid artery stenosis ≧70% (North American Symptomatic Carotid Endarterectomy Trial) were randomly assigned to filter-protected or unprotected CAS. Diffusion-weighted magnetic resonance imaging (DWI) of the brain was performed before and at 3 time points after CAS. In a subset of patients, high-intensity transient signals on transcranial Doppler (TCD) were recorded with categorisation of emboli. Data were independently reviewed off-site. Results: There were no significant differences in mean age, proportion of octogenarians or presenting symptoms between the groups. On procedural DWI (1–3 and 24 h after stenting), there were 7/24 (29%) and 4/22 (18%) new lesions in protected and unprotected patients respectively (p = 0.38). At 30 days there were 9/33 (26%) and 4/33 (12%) lesions in protected and unprotected patients, respectively (p = 0.1). On TCD there were significantly more signals in total as well as particulate emboli during filter-protected CAS (426.5 and 251.3) than during unprotected CAS (165.2 and 92) – p = 0.01 and 0.03, respectively. Conclusions: Filter-protected CAS is associated with an increase in new lesions on DWI and significantly higher rates of total and particulate microembolisation on TCD than unprotected CAS. The clinical significance of these findings requires further study.

Clinical Risk Associated With Contrast Angiography in Metformin Treated Patients: a Clinical Review

Recently, concern has been expressed about the hazards of lactic acidosis following the use of intravascular iodinated contrast agents in patients taking metformin. In response the Royal College of Radiologists have issued guidelines for the management of these patients. We have reviewed the reported cases of lactic acidosis and identified that in all cases underlying renal impairment existed. To examine this further we reviewed the notes of 33 in-patients receiving metformin who underwent contrast angiography in our hospital. Twenty-nine patients had a normal serum creatinine prior to the procedure and none had a rise following angiography. Four patients had an abnormal serum creatinine prior to angiography, all four patients showed significant deterioration and all four patients died, two from unrelated causes and two from acute renal failure and acidosis. These data strongly highlight the hazards of intravascular contrast radiology in diabetic patients with pre-existing renal impairment. We have failed to find evidence in support of the Royal College of Radiologists recommendation; instead we recommend that in those patients taking metformin with evidence of renal impairment metformin should be stopped and diabetic control obtained using alternative therapy before proceeding with angiography. Patients with normal renal function taking metformin are not at risk of lactic acidosis following the use of iodinated contrast agents for angiography.

Treatment of chronic iliac artery occlusions by means of percutaneous endovascular stent placement

PURPOSE A retrospective evaluation of outcomes in patients with chronic iliac occlusions treated with insertion of metallic endovascular stents, without previous thrombolysis, on an intention-to-treat basis. MATERIALS AND METHODS Seventy-two patients with chronic iliac occlusion underwent attempted stent placement from either the ipsilateral or contralateral femoral artery. There were 49 men and 23 women. Mean age was 63.1 years (range, 39-88 years). A total of 89 stents were deployed in 67 patients. Follow-up was from 24 to 69 months (mean, 37.5 months). RESULTS Stents were successfully deployed in 67 patients (93%), with two early failures, giving a primary success rate of 90%. There were five significant and four insignificant procedural complications. There were four late failures (all within the first year) and four non-stent-related deaths. CONCLUSION Endovascular stent placement offers an alternative to surgery in the treatment of chronic iliac occlusions.

Long-term retrievability of IVC filters: should we abandon permanent devices?

Thromboembolic disease produces a considerable disease burden, with death from pulmonary embolism in the UK alone estimated at 30,000–40,000 per year. Whilst it is unproven whether filters actually improve longevity, the morbidity and mortality associated with thromboembolic disease in the presence of contraindications to anticoagulation is high. Thus complications associated with filter insertion, and whilst they remain in situ, must be balanced against the alternatives. Permanent filters remain in situ for the remainder of the patient’s life and any complications from the filters are of significant concern. Filters that are not permanent are therefore attractive in these circumstances. Retrievable filters, to avoid or decrease long-term filter complications, appear to be a significant advance in the prevention of pulmonary embolism. In this review, we discuss the safety and effectiveness of both permanent and retrievable filters as well as the retrievability of retrievable inferior vena cava (IVC) filters, to explore whether the use of permanent IVC filters can be abandoned in favor of retrievable filters. Currently four types of retrievable filters are available: the Recovery filter (Bard Peripheral Vascular, Tempe, AZ, USA), the Günther Tulip filter (Cook, Bloomington, IN, USA), the OptEase Filter (Cordis, Roden, The Netherlands), and the ALN filter (ALN Implants Chirurgicaux, Ghisonaccia, France). Efficacy and safety data for retrievable filters are as yet based on small series, with a total number of fewer than 1,000 insertions, and follow-up is mostly short term. Current long-term data are poor and insufficient to warrant the long-term implantation of these devices into humans. The case of fractured wire from a Recovery filter that migrated to the heart causing pericardial tamponade requiring open heart surgery is a reminder that any new endovascular device remaining in situ in the long term may produce unexpected problems. We should also bear in mind that the data on permanent filters are much more robust, with reports on over 9,500 cases with follow-up of up to 8 years. The original implantation time of 10–14 days has been extended to more than 100 days as the mean implantation time with some of the filter types. Follow-up (preferably prospective) is necessary for all retrievable filters, whether or not they are retrieved. Until these data become available we should restrict ourselves to the present indications of permanent and retrievable filters. If long-term follow-up data on larger numbers of cases confirm the initial data that retrievable filters are as safe and effective as permanent filters, the use of the retrievable filters is likely to expand.

Timing and frequency of complications after carotid artery stenting: what is the optimal period of observation?☆

OBJECTIVE Currently our standard of practice is that patients undergoing carotid artery stenting (CAS) may be safely discharged on the first day post-procedure. However, many patients are completely independent on the evening of procedure. Therefore we sought to establish the safety and feasibility of same-day discharge by assessing frequency and time of complications in the first 30 days after CAS. METHOD Case records for 208 consecutive patients who had undergone CAS from October 1999 to October 2002 were retrospectively reviewed. Excluded were four cases in which combined CAS and carotid endarterectomy was performed to treat synchronous stenosis. Of the remaining 204 cases, involving 201 patients (three patients underwent staged bilateral CAS), 173 (84.8%) were symptomatic and 31 (15.2%) were asymptomatic. RESULT Thirty-eight major events or death (inclusive of all neurologic events and any complications that required treatment) were recorded in the first 30 days after CAS, for an event rate of 18.6% per case. These were 7 (3.4%) major access site complications; 18 (8.8%) neurologic events, of which 10 (4.9%) were transient ischemic events and 8 (3.9%) were strokes (including minor, major, and fatal stroke); 8 (3.9%) cardiovascular complications; and five (2.5%) other events. Twenty (52.6%) events occurred in the first 6 hours after CAS, 2 (5.3%) between 6 and 12 hours, 3 (7.9%) between 12 and 24 hours, and 13 (34.2%) 24 hours to 30 days post procedure. Four (2.0%) deaths were recorded in this period, 1 secondary to stroke, 1 from a perforated myocardium from a temporary pacing wire, and 2 from unrelated causes. The 30-days stroke and death rate was 5.4% (11 of 204 patients). CONCLUSION Time of complications suggests that outpatient performance of CAS is feasible and safe in selected patients.

Joint UK societies' 2014 consensus statement on renal denervation for resistant hypertension.

Resistant hypertension continues to pose a major challenge to clinicians worldwide and has serious implications for patients who are at increased risk of cardiovascular morbidity and mortality with this diagnosis. Pharmacological therapy for resistant hypertension follows guidelines-based regimens although there is surprisingly scant evidence for beneficial outcomes using additional drug treatment after three antihypertensives have failed to achieve target blood pressure. Recently there has been considerable interest in the use of endoluminal renal denervation as an interventional technique to achieve renal nerve ablation and lower blood pressure. Although initial clinical trials of renal denervation in patients with resistant hypertension demonstrated encouraging office blood pressure reduction, a large randomised control trial (Symplicity HTN-3) with a sham-control limb, failed to meet its primary efficacy end point. The trial however was subject to a number of flaws which must be taken into consideration in interpreting the final results. Moreover a substantial body of evidence from non-randomised smaller trials does suggest that renal denervation may have an important role in the management of hypertension and other disease states characterised by overactivation of the sympathetic nervous system. The Joint UK Societies does not recommend the use of renal denervation for treatment of resistant hypertension in routine clinical practice but remains committed to supporting research activity in this field. A number of research strategies are identified and much that can be improved upon to ensure better design and conduct of future randomised studies.

Complications following Carotid Angioplasty and Carotid Stenting in Patients with Symptomatic Carotid Artery Disease

Background: We review a single centre’s experience of the endovascular treatment of carotid artery disease, present the 30-day and 1-year complication rates and assess whether changes in technique are associated with a change in clinical outcome. Methods: Patients who underwent carotid angioplasty with or without stenting for symptomatic ≧70% carotid artery stenosis secondary to atherosclerosis were included. 333 procedures were performed, i.e. angioplasty alone (86), stent without cerebral protection (150) and stent with cerebral protection (97). Results: At 30 days, the total major disabling stroke and all death rate was 3.0%. For angioplasty alone, this was 2.3%, for stent without cerebral protection 4.0% and for stent with cerebral protection 2.1%. If non-stroke-related deaths were excluded, it was 2.3, 3.3 and 0%, respectively. After 30 days, the 1-year ipsilateral stroke rate was 0.8%. Conclusions: Carotid artery stenting, in particular with a cerebral protection device, is a safe alternative to carotid endarterectomy for the treatment of symptomatic high-grade carotid artery disease.

Randomized clinical trial of stents versus angioplasty for the treatment of iliac artery occlusions (STAG trial).

The management of total iliac artery occlusion is now undertaken routinely using percutaneous techniques but there are no controlled data to indicate whether either balloon angioplasty or stent placement is preferable. This was a multicentre randomized trial to assess whether stents confer any safety or efficacy advantage over balloon angioplasty for complete iliac artery occlusion.