CAPTURE: Evaluation of Carotid Stenting in Community Practice

Luis Gruberg, MD, FACC

Disclosures

July 20, 2006

Editorial Collaboration

Medscape &

"Further analysis of these data will certainly help us understand the best therapeutic options for patients with symptomatic and asymptomatic carotid artery stenosis."

William A. Gray, MD (Columbia University Medical Center, New York, NY) for the CAPTURE Investigators

Several prospective, randomized trials have shown the benefit of carotid endarterectomy over best medical therapy alone for the treatment of significantly obstructive carotid lesions. Of importance, the observed benefit was directly related to the severity of stenosis. Carotid artery stenting (CAS) for the treatment of carotid artery stenosis has been shown in a series of studies and registries to be as safe and as effective as carotid endarterectomy, especially in high-risk patients. The Carotid ACCULINK/ACCUNET Post Approval Trial to Uncover Rare Events (CAPTURE)[1] study was a US Food and Drug Administration-mandated post-approval surveillance study of the RX ACCULINK carotid stent system used in conjunction with the RX ACCUNET distal embolic protection system; both devices are manufactured by Guidant Corporation (Indianapolis, Indiana).

Study Design and Methods

The CAPTURE registry assessed whether CAS using the RX ACCULINK/RX ACCUNET system can be performed safely by physicians with varying levels of experience. In addition, the surveillance study evaluated the ability to identify rare and unanticipated device-related events, as well as the adequacy of Guidant's physician training program.

All patients underwent a neurologic exam 24 hours prior to undergoing the procedure and at 30 days post procedure. Enrollment was limited to a maximum of 40 patients per center, and no more than one third of all patients would be enrolled at hospitals with a high level of experience.

The primary endpoint was the composite of death, stroke, and myocardial infarction (MI) at 30 days. Other endpoints included the composite of all stroke and death, the composite of major stroke and death, and the composite of death, all stroke, major stroke, minor stroke, and MI.

Outcomes of CAPTURE patients were compared with those reported in the ACCULINK for Revascularization of Carotids in High-Risk Patients (ARCHeR) trial.

Results

Enrollment and follow-up remains ongoing. Data from 2500 patients are available for analysis. Baseline characteristics of the CAPTURE patients compared with those enrolled in ARCHeR are shown in Table 1.

Table 1. Baseline Characteristics: CAPTURE vs ARCHeR
  CAPTURE
(n = 2500)
ARCHeR
(n = 581)
Male gender (%)* 61 67
Age (yrs)* 73 70
Age ≥ 80 yrs (%)* 24 16
Age ≥ 65 yrs (%)* 81 73
Symptomatic (%)* 9 24
Diabetes (%) 35 38
Hypertension (%)* 89 84
Hypercholesterolemia (%)* 79 73
Congestive heart failure (%)* 15 34
Current smoker (%) 20 19
Renal failure (%)* 6 3
*P < .05 for comparison

The majority of physicians (71%) performing the procedures had a medium level of experience (defined as having performed 10 carotid stent procedures as the primary operator), and 82% of patients were enrolled at hospitals that enrolled between 10 and 39 patients in the registry. More than half of all the procedures (55%) were performed by interventional cardiologists, 22% by interventional neuroradiologists, and 15% by interventional radiologists.

The 30-day primary endpoint (death, stroke, and MI) was lower in CAPTURE than in ARCHeR (5.7% vs 8.3%, respectively; P < .05), as were the rates of stroke/death, major stroke/death, and each of the individual components of the endpoint (Figure 1 and Figure 2).

Figure 1. CAPTURE vs ARCHeR: death/stroke/MI; stroke/death; and major stroke/death at 30 days. *P < .05.
Figure 2. CAPTURE vs ARCHeR: death, all stroke, major stroke, minor stroke, myocardial infarction. *P < .05.

When the same analysis was performed in asymptomatic patients (comprising the majority of patients in both registries), the results were similar, with lower event rates seen in CAPTURE (Table 2). However, a similar analysis of symptomatic patients demonstrated that CAPTURE patients had higher mortality rates, whereas the other endpoints were similar.

Table 2. CAPTURE vs ARCHeR: Events -- Asymptomatic and Symptomatic
Events (%) Asymptomatic Symptomatic
CAPTURE
(n = 2267)
ARCHeR
(n = 443)
CAPTURE
(n = 233)
ARCHeR
(n = 138)
Death/stroke/MI 4.9 6.8 14.2 13.0
Death 1.3 2.0 4.3 2.2
Stroke 3.5 3.8 11.2 10.9
MI 0.7* 2.5 2.6 2.2
All stroke/death 4.4 5.4 12.0 11.6
Major stroke/death 2.2 2.3 6.0 5.1
MI = myocardial infarction

*P < .05

Figure 3 depicts event rates by symptom status in CAPTURE patients.

Figure 3. Events by symptom status -- CAPTURE patients (N = 2500).

Analysis by physician experience showed that the incidence of events was not influenced by the level of operator experience. Of interest, those with high levels of experience had slightly higher event rates than physicians with a low level of experience, but the difference was not statistically significant (Figure 4 and Figure 5).

Figure 4. CAPTURE: stroke rates by physician experience. High level of experience = previous investigational experience, 5 as primary operator, using the RX ACCULINK/RX ACCUNET system; Medium level of experience = 10 carotid stent procedures as the primary operator; Low level of experience = adequate interventional experience as a primary operator (25 carotid angiograms + 10 peripheral procedures with self-expanding stents + 10 procedures with 0.014" RX systems).
Figure 5. CAPTURE: rates of death/stroke/MI; stroke/death; and major stroke/death by physician experience. High level of experience = previous investigational experience, 5 as primary operator, using the RX ACCULINK/RX ACCUNET system; Medium level of experience = 10 carotid stent procedures as the primary operator; Low level of experience = adequate interventional experience as a primary operator (25 carotid angiograms + 10 peripheral procedures with self-expanding stents + 10 procedures with 0.014" RX systems).

Octogenarian patients, who comprised 24% of the CAPTURE population, had the highest rates of adverse events, especially those who were symptomatic. Among symptomatic patients, the rate of the primary endpoint was 14.2% in patients aged ≥ 80 years vs 4.9% in patients < 80 years of age (P < .05).

Investigators reported that there were no unanticipated adverse events.

Conclusions
  1. Community-based CAS provides excellent results.

  2. Stroke and death rates for asymptomatic patients aged < 80 years approach the outcomes associated with surgical endarterectomy in high-risk patients.

  3. Rollout of therapy to physicians with varying levels of experience achieved excellent results comparable to those observed in ARCHeR.

  4. Training experience appears to have eliminated influence of previous experience on outcomes.

  5. Future multivariate analyses may facilitate patient selection for CAS.

Viewpoint

The results from CAPTURE provide valuable data regarding "real-world" carotid intervention. The excellent outcome of patients at high surgical risk who undergo CAS in a variety of settings is clearly shown by this postmarketing surveillance. Also, the data remind us of the risks involved with the treatment of octogenarian patients, especially those who already had a cerebrovascular event. I find it interesting that the outcomes were favorable even when the procedure was performed by physicians with a low level of experience and in low-volume centers, which, in a previous trial, was a predictor of poor outcome. Further analysis of these data will certainly help us understand the best therapeutic options for patients with symptomatic and asymptomatic carotid artery stenosis.

Reference
  1. Gray WA, Yadav J, Hopkins LN, et al. CAPTURE 3000: Report of the largest US multicenter experience in carotid stenting for high surgical risk patients. Program and abstracts from the American College of Cardiology 55th Annual Scientific Session; March 11-14, 2006; Atlanta, Georgia. Abstract 422-16.

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.

processing....