EXPERT ANALYSIS FROM THE NORTHWESTERN VASCULAR SYMPOSIUM
CHICAGO (FRONTLINE MEDICAL NEWS) – Modern medical management is as effective as carotid artery reintervention for stroke prevention in asymptomatic patients with a carotid in-stent restenosis in excess of 70%, Jayer Chung, MD, asserted at a symposium on vascular surgery sponsored by Northwestern University.
That, in his view, makes medical management the clear preferred strategy.
“A carotid intervention costs about $17,000. If we choose medical management, we can better allocate our resources. Furthermore, if it doesn’t really help, I don’t want to do one of these procedures to my patients. I want to avoid the periprocedural risks. Early on, the stroke and death rates are higher in the intervention arm,” explained Dr. Chung , a vascular surgeon at Baylor College of Medicine, Houston.
A growing body of evidence, mainly from nested cohorts within randomized controlled trials, indicates that the late ipsilateral stroke rate associated with post–carotid endarterectomy restenosis (CEA) is much higher than that for carotid in-stent restenosis (C-ISR). In a recent meta-analysis of nine randomized trials, the difference in risk was more than 10-fold, with a 9.2% stroke rate at a mean of 37 months of follow-up in patients with post-CEA restenosis, compared with a 0.8% rate with 50 months of follow-up in patients with C-ISR ( Eur J Vasc Endovasc Surg. 2017 Jun;53:766-75 ).
“These pathologies behave very, very differently,” Dr. Chung observed. “The C-ISR lesions tend to be less embologenic.”
C-ISR is an uncommon event. Extrapolating from the landmark CREST (Carotid Revascularization Endarterectomy versus Stenting Trial) and other randomized trials, about 6% of patients who undergo percutaneous carotid stenting will be develop C-ISR within 2 years. But since the proportion of all carotid revascularizations that are done by carotid stent angioplasty has steadily increased over the past 15 years as the frequency of CEA has dropped, C-ISR is a problem that vascular specialists will continue to encounter on a regular basis.
Symptomatic C-ISR warrants reintervention; broad agreement exists on that. But there is a paucity of data to guide treatment decisions regarding asymptomatic yet angiographically severe C-ISR. Indeed, Dr. Chung was lead author of the only retrospective study of the natural history of untreated C-ISR, as opposed to carefully selected cohorts from randomized trials involving highly experienced operators. This study was a retrospective review of 59 patients with 75 C-ISRs of at least 50% seen at a single Veterans Affairs medical center over a 13-year period. Three-quarters of the ISRs were asymptomatic.
Forty of the 79 C-ISRs underwent percutaneous intervention at the physician’s discretion. Those patients did not differ from the observation-only group in age, comorbid conditions, type of original stent, or clopidogrel use. Reintervention was safe: There was one stent thrombosis resulting in stroke and death within 30 days in the reintervention group and no 30-day strokes in the observation-only group. During a mean 2.6 years of follow-up, the composite rate of death, stroke, or MI was low and not statistically significantly different between the two groups. Indeed, during up to 13 years of follow-up only one patient with untreated C-ISR experienced an ipsilateral stroke, as did two patients in the percutaneous intervention group ( J Vasc Surg. 2016 Nov;64:1286-94 ).
Dr. Chung does the math
According to data from the National Inpatient Sample, vascular surgeons do an average of 15 carotid angioplasty and stenting procedures per year. If 6% of those stents develop in-stent restenosis, and with a number needed to treat with revascularization of 25 to prevent 1 stroke, Dr. Chung estimated that hypothetically it would take the typical vascular surgeon 27 years to prevent one stroke due to C-ISR.
“That’s a very long time to prevent one stroke, in my opinion,” he said.
How his study has affected his own practice
Dr. Chung now intervenes only for symptomatic C-ISRs, and only after an affected patient is on optimal medical therapy, including a statin and dual-antiplatelet therapy.
“I try to do an open procedure if possible, especially if the restenosis is above C-2. The ones I tend to do percutaneously are the post-irradiation stenoses or those with excessive scarring, and I use a cerebral protection device,” the surgeon explained.
He emphasized, however, that the final word on the appropriate management of C-ISRs isn’t in yet. A standardized definition of C-ISR is needed, as are multicenter prospective registries of medically managed patients as well as those undergoing various forms of reintervention. And a pathologic study is warranted to confirm the hypothesis that the histopathology of post-CEA and post-stent restenosis – and hence the natural history – is markedly different.
Dr. Chung reported having no financial conflicts regarding his presentation.