The clinical application of a scoring protocol to select endarterectomy or stenting for carotid artery stenosis
In this study, we verified the actual application of our scoring protocol to patients with carotid stenosis. In our patient population, a majority (93.3%) of treatment options were chosen per protocol. Among those with equal scores and those who should have undergone EA per protocol, patients tended to choose ACS over EA. Seven patients who would have had CEA (based on the protocol) actually had CAS. We believe that it is not necessary to determine which treatment arm is better than the other between CAS and CEA. We believe that no future effort should be made to choose one or the other. Instead, we should identify which treatment option is best suited for each patient. Simultaneous consideration of ACE and ACS (with respect to each patient) should improve overall clinical outcomes.
Our protocol was developed using clinically relevant preoperative factors (in terms of risk/benefit) that had been identified in several previous articles13. Of the 192 articles we found on PubMed and Medline, 28 were selected as references and they all met the following criteria: (1) single or multiple randomized clinical trials; (2) review articles in journals with high impact factors (≥ 6); or (3) well-designed case-control studies including large numbers of patients. We made a general plan for our protocol based on these studies. We then specified the exact indicative values for each factor suitable for our institution. For example, we gave a point for moderate calcification around carotid stenosis with a concentric circumference of 90 to 270 degrees with maximum calcified plaque thickness ≥ 3 mm as favorable for CEA. We also gave one point for lesion length ≥ 30 mm as favorable for CEA14,15,16,17,18,19,20. However, these factors are not contraindications to performing a CAS. Although we gave these points in favor of CEA, we expected that patients would prefer ACS by choice. This method allowed us to evaluate the real application of our protocol.
Of the seven violation cases, all patients refused to undergo CEA. These patients preferred CAS because it is minimally invasive, produces less scarring, and does not require general anesthesia. It is certainly possible that emotions and indirect outside influences influenced the patients’ decision to undergo SAC compared to what was recommended by the medical evidence. These same factors may also have influenced patient decisions when scores were equal between CEA and CAS. Of the 37 patients with equal scores on the protocol, 28 (75.7%) underwent CAS. We preferred CAS to CEA in emergency situations, such as acute ischemic stroke. We performed CSA in 11 patients during intra-arterial thrombectomy or emergency diagnostic angiography.
Based on previous great trials4,5,6,7,8,9,10,11US guidelines in 2014 recommended CEA as the first treatment option in patients with severe symptomatic stenosis12. However, CAS has become an option based on several new recommendations if the rate of stroke or peri-procedural death is 4,5,6,7,8,9,10,11,12. Although our sample size was very small, there were no permanent neurological deficits or deaths in our series. This suggests that our scoring protocol might be applicable to the real-world clinical setting. The 30-day mortality (0%), major stroke (0%), minor stroke (3.1%), and myocardial infarction (0%) rates were similar or better in our series than those previous major trials. Our clinical results were also comparable between the two treatment options. The 12-month results of the 105 consecutive patients in this study may be sufficient to recommend our protocol for determining the appropriate treatment for carotid stenosis.
We considered additional factors for the modification of our protocol. First, atrial fibrillation with anticoagulation may fall into the category of “ACE favorable” because dual antiplatelet therapy for CAS may increase the risk of bleeding. In addition, an acute ischemic stroke requiring mechanical thrombectomy associated with occlusions of large arteries due to severe carotid stenosis may belong to the category of “favorable CAS”, given its emergent nature. Also, the sign of the string requires more precise indicative values. One point can be given to the CEA if the length of the sign of the string is ≥ 2 cm. Otherwise, both treatment options are applicable. We did not experience restenosis after CAS in this present study. However, if we had, it would probably fall into the category of “favorable CAS”. Finally, we should have included an indication to choose CEA or CAS if absolute CAS and absolute CEA are opposed. We acknowledge that our small sample size is a limitation of this study. Yet, we suspect it is enough to show the trend of real-world practice with the application of our protocol and the shift to CAS and minimally invasive treatment.
In the treatment of patients with carotid artery stenosis, CAS and CEA should be considered simultaneously together, not against each other. In the present study, the majority of treatment options were chosen per protocol. Among those with equal scores and those who should have undergone EA per protocol, patients tended to choose ACS over EA. Our scoring protocol can be used to weigh these options and applied in clinical practice.