Intracranial Stenting May Be Safer in Clinical Trials vs. Real-world Practice

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Postoperative outcomes after intracranial stenting are worse when the procedure is performed in clinical practice rather than in the context of a trial, according to a large registry study appearing online October 17, 2013, in Stroke.

SAMMPRIS Halted Early

Researchers led by Farhan Siddiq, MD, of the University of Minnesota (Minneapolis, MN), were spurred in their investigation after the SAMMPRIS (Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis) trial was halted early due to a higher rate of 30-day stroke and death with endovascular therapy vs. medical therapy.

Dr. Siddiq and colleagues looked at 3,447 ischemic stroke patients from the National Inpatient Sample (NIS) who were treated with intracranial stenting from 2008 to 2010 either as part of (n = 223) or outside (n = 3,224) a clinical trial.

Clinical trial patients were older (68 vs. 65 years; P = 0.008), while sex and medical comorbidities were similar between the groups.

There were trends for a higher rate of the composite endpoint of postoperative stroke, cardiac complications, and mortality in patients treated as standard of care outside of a trial setting. Trial participants also had shorter hospital stays and were more likely to be discharged to home rather than to rehab or a nursing home (table 1).

Table 1. Postoperative Outcomes of Intracranial Stenting

On multivariable adjustment, patients treated outside of clinical trials continued to show a trend for an increase in the composite endpoint (OR 3.4; 95% CI 0.5-21.5; P = 0.1) and an increased risk of discharge to rehab/nursing home (OR 3.5; 95% CI 1.2-9.7; P = 0.01). Postoperative mortality was somewhat more likely in the outside-of-trials group (adjusted OR 2.0; 95% CI 0.2-14.4; P = 0.5).

In a subgroup analysis of Medicare patients, the composite endpoint remained more common in the nonclinical trials group, but the difference was not significant (14.7% vs. 7.2%; P = 0.4; adjusted OR 3.2; 95% CI 0.5-22.8; P = 0.3). There were no neurological complications reported in the clinical trials group.

“Intracranial stent placement procedures outside a clinical trial have higher rates of postoperative stroke, cardiac complication, and mortality,” Dr. Siddiq and colleagues conclude. One explanation for this, they note, may be the “cherry-picking phenomenon,” whereby patients treated within clinical trials have more favorable characteristics than those treated as a part of routine practice.

Outcomes Not So Good in Reality

In a telephone interview with TCTMD, Philip M. Meyers, MD, of Columbia University Medical Center (New York, NY), who served as a SAMMPRIS investigator, noted that, in the trial, “results were not favorable for intracranial stenting. There was concern that previous registry data and experience in routine clinical practice had been better. This study by Siddiq et al suggests otherwise: the results of intracranial stenting in clinical practice are even worse than in SAMMPRIS based on the NIS dataset.”

Going forward, Dr. Meyers continued, “this procedure probably ought to be performed in the context of a trial. It is more important than ever to prove that intracranial stenting remains a relevant procedure for patients refractory to medical therapy.”

He expressed concern about the proliferation of other intracranial endovascular interventions without the data to support it. “We still have a lot of work to do,” Dr Meyers emphasized. “I believe intracranial procedures are clinically important and offer minimally invasive solutions to many complex vascular problems, but they must be appropriately applied by highly trained and skilled clinicians.”

 

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Source:
Siddiq F, Adil MM, Norby K, et al. Intracranial stent placement for symptomatic intracranial stenosis as part of a clinical trial versus outside a clinical trial. Stroke. 2013;Epub ahead of print.

 

 

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