Discussion

Article Outline

• Copyright

Dr Wei Zhou (Stanford, Calif). My first question is regarding compatibility of the two groups of patients. Several risk factors including congestive heart failure (CHF), chronic renal failure, and chronic obstructive pulmonary disease (COPD) are known to negatively impact carotid interventions, but these were not evaluated in this study. Based on the Kaplan-Meier survival curve of your patients, male patients had a significant drop out at 6 months while female patients tended to drop out around 20 months. So my first question is whether you really compared similar groups of patients? Is outcome of carotid artery stenting (CAS) for female patients truly equivocal to men, or they are just healthier than their male counterparts?

You mentioned that the indications for significant stenosis were based on ultrasound scan, magnetic resonance angiography (MRA), and carotid angiogram. Giving the fact that MRA tends to overestimate the lesions and ultrasound scan is a fairly good non-invasive screen tool, my second question is: Why an ultrasound scan was not used for all patients and were those imaging studies validated and cross-referenced?

In your manuscript, you mentioned that the size of your predilatation balloon was uniformly 4 mm × 50 mm. The size is a little bigger than most surgeons would have used. Were there any reasons for oversizing the predilatation balloon?

The last question is regarding ultrasound scan characteristics of lesions. Studies have shown that ultrasound scan characteristics are important, maybe more so than the degree of stenosis. Have you looked into and will you plan to evaluate ultrasound scan characteristics of the lesion in the future?

Dr Lee Goldstein. To begin, let me address your first question. As far as other preoperative characteristics, we have been actively trying to pursue the maintenance of our dataset and we have been trying to add to some of the preoperative characteristics.

I agree, one of the troubles we've had has been many of the patients we've done our carotid angioplasty and stenting on have come as referrals from other medical centers, so we have been trying to look back and get more data on these patients. Adding things like congestive heart failure, renal failure, and COPD would shed some light on whether or not these patients are different.

One thing that struck us was the remarkable similarity between our patient populations. As we processed this data, we were surprised to see just how close they were, that we saw so few differences. So I agree, adding more data points will be helpful and we will go back and try to do that.

With regard to preoperative workup, I don't have the breakdown as to which patients were evaluated preoperatively by MRA angiography vs ultrasound. Anecdotally, I can tell you the vast majority of these patients were evaluated with a preoperative ultrasound scan and then that was confirmed with or without an MRA or angiography. Every one of them underwent angiography prior to the placement of a carotid stent during the procedure, so the lesion was confirmed intraoperatively prior to placement of the carotid stent. I don't think any of them had solely an MRA. But they all had a preoperative duplex scan and then a preplacement angiogram.

With regard to the predilatation balloon, that may be an error in the manuscript. I believe it's a 4 × 20 balloon. And we'll make sure that we address that.

And lastly, as far as ultrasound scan characteristics, I think that there has been some recent literature looking both at specifically female-related ultrasound scan characteristics, that females demonstrate higher velocities with regard to specific lesion characteristics, and that females will demonstrate higher velocities for specific stenosis sizes. We have not yet gone back and evaluated our particular ultrasound scan characteristics for these patients.

Additionally, there has been some new data looking at evaluation of post carotid stenting ultrasound scan characteristics and velocities. We can go back and look specifically at those issues as well.

Dr Anil Hingorani (Brooklyn, NY). How many of your patients that had strokes didn't have embolic protection devices, and why didn't they?

Dr Goldstein. There were no patients that suffered a stroke that didn't have an embolic protection device.

Dr Hingorani. You had a fair number that didn't have embolic protection devices used. What were the reasons?

Dr Goldstein. There were 13 patients in the study without embolic protection devices. I don't know the reasons why they didn't at the time.

Dr Hingorani. All of the strokes occurred without embolic protection?

Dr Goldstein. No. Every patient who suffered a stroke had an embolic protection device placed.

Dr Karl Illig (Rochester, NY). Dr. Goldstein, luckily your ages are the same in each group so your conclusions aren't affected, but can you defend your choice of age over 80 as a high-risk criteria for surgery or, in other words, why you feel stenting is safer than endarterectomy in elderly patients? I would say the opposite is true.

Dr Goldstein. I would agree. I don't know. This has been the high-risk group that has been used for our institution in our carotid stenting group.

Dr Illig. Can you defend that?

Dr Ageliki Vouyouka (New York, NY). The data collection of this study started early in 2003. At that time, the worst outcomes from carotid stenting in octogenarians, as shown in the lead in phase of the CREST trial, were not yet known. Therefore, initially, one of the high-risk criteria to consider carotid stenting was age >80 years. This criterion was abandoned in later years.

Dr Taras Kucher (Trumbull, Conn). In this study, both males and females had approximately 4-mm size carotid arteries. It is postulated in prior publications, that the increased risk of complications in women (particularly re-stenosis) is secondary to smaller size of the vessels. Do you have an explanation for this discrepancy?

Dr Goldstein. Correct. We've noted a number of papers that have demonstrated women to have smaller carotid arteries. In fact, that's the hypothesis as to why they've done poorly surgically, that technically they've had harder arteries to work with and why they've done better with patching. We had two people go back independently to review the angiographic data and they got similar measurements. So I can't explain why our cohort had these results, but we had in fact similar sizes between the men and the women for the internal carotids.

We did have similar findings as other groups, although they didn't reach significance, for internal carotid to common carotid ratios, and for outflow to inflow ratios for women compared to men. But as far as absolute sizes, we did not demonstrate a difference between men and women.