Embolic Protection and Platelet Inhibition During Renal Artery Stenting - Embolic Protection and Platelet Inhibition During Renal Artery Stenting

May 27, 2008
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Author/Summarized by Author:
Anthony A. Bavry, MD, MPH, FACC
Summary Reviewer:
Anthony A. Bavry, MD, MPH, FACC
Trial Sponsor:
University of Toledo, Health Science Campus
Date Published:
01/01/2008
Date Updated:
05/27/2008
Original Posted Date:
05/27/2008
References

Description:

The goal of the trial was to evaluate the change in glomerular filtration rate (GFR) after renal artery stenting (RAS) with Angioguard, RAS with abciximab, and RAS with Angioguard/abciximab, compared with RAS alone among patients with renal artery stenosis.

Hypothesis:

The use of adjuvant Angioguard or abciximab during RAS will be more effective in preserving renal function.

Study Design

  • Randomized
  • Factorial

Patients Screened: 390
Patients Enrolled: 100
Mean Follow Up: 1 month
Mean Patient Age: 73 years
Female: 56

Patient Populations:

• Patients with renal artery stenosis at least 50% suitable for embolic protection
• History of hypertension, renal insufficiency, heart failure, or angina with poorly controlled hypertension

Exclusions:

• Age <18 years
• Pregnancy
• Life expectancy <6 months
• Dialysis
• Renal transplant
• Stenosis not amenable to percutaneous revascularization
• Allergy to study medication
• Unrelated renal disease
• Aortic aneurysm
• Renal size <8 cm
• Renal artery restenosis
• Treatment of a side branch or distal stenosis
• Active bleeding
• Stroke in the last 2 years
• Coagulopathy or thrombocytopenia
• Major surgery or trauma in the last 6 months
• Intracranial neoplasm
• Arteriovenous malformation
• Nonstudy procedure in the last 24 hours

Primary Endpoints:

Percent change in GFR at 1 month

Secondary Endpoints:

Histopathological analysis of filter devices for platelet-rich thrombus

Drug/Procedures Used:

Patients with renal artery stenosis were randomized to RAS with Angioguard (n = 22), RAS with abciximab (n = 25), RAS with Angioguard/abciximab (n = 25), or RAS alone (n = 28).

Concomitant Medications:

At baseline, the use of aspirin ranged from 80% in the RAS plus abciximab group to 93% in the RAS alone group. Thienopyridine use ranged from 40% in the RAS plus abciximab group and RAS and Angioguard/abciximab group, to 61% in the control group.

Principal Findings:

The volume of contrast delivered was 173 ml in the RAS plus Angioguard group, 139 ml in the RAS plus abciximab group, 148 ml in the RAS plus Angioguard/abciximab group, and 115 ml in the RAS alone group.

The change in GFR from baseline to 1 month was 61-52 ml/min in the RAS plus Angioguard group (p < 0.05), 66-58 ml/min in the RAS plus abciximab group (p < 0.05), 52-54 ml/min in the RAS plus Angioguard/abciximab group (p = ns), and 59-52 ml/min in the RAS alone group (p < 0.05). The percent change in GFR with RAS plus Angioguard/abciximab compared with the percent change in RAS alone was significant (p < 0.01); however, the GFR at 1 month was similar between the groups (54 ml/min with RAS plus Angioguard/abciximab vs. 52 ml/min with RAS alone).

Platelet-rich thrombi were reduced from 42% versus 7% with abciximab (p < 0.01); however, there was no difference in atheromatous debris (21% vs. 17%, p = ns) or fibrin-rich thrombi.

Major bleeding occurred in 5% of the RAS plus Angioguard group, 4% of the RAS plus abciximab group, 12% of the RAS plus Angioguard/abciximab group, and 7% of the RAS alone group.

Interpretation:

Among patients with renal artery stenosis, RAS plus Angioguard, RAS plus abciximab, and RAS alone were all associated with a decline in GFR at 1 month. The use of RAS plus Angioguard/abciximab was associated with a similar GFR at follow-up. The clinical significance of this finding is unknown because there was no difference in the final GFR in the RAS plus Angioguard/abciximab group (54 ml/min) compared with the RAS alone group (52 ml/min).

This trial is limited by a lack of power because there were only 25 patients in the RAS plus Angioguard/abciximab group. Although the post-hoc finding of combination adjuvant therapy is interesting, it will need to be validated in an adequately powered randomized trial to specifically address these two strategies. Increased bleeding with combination adjuvant therapy also remains a possibility. Last, this trial needs to be placed in context with the recently reported ASTRAL trial, where RAS offered no advantage over medical therapy among patients with renal artery stenosis.

References:

Cooper CJ, Haller ST, Colyer W, et al. Embolic protection and platelet inhibition during renal artery stenting. Circulation 2008;117:2752-60.

Keywords: Renal Insufficiency, Renal Artery, Renal Artery Obstruction, Platelet Aggregation Inhibitors, Heart Failure, Glomerular Filtration Rate, Blood Platelets, Immunoglobulin Fab Fragments, Hypertension, Peripheral Vascular Diseases


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