Natural History of Internal Carotid Artery Stenosis Progression

Abstract

To investigate the natural history of internal carotid artery (ICA) stenosis progression. This single-institution retrospective cohort study analyzed patients diagnosed with internal carotid artery stenosis of 50% or greater on duplex ultrasound (DUS) from 2015 to 2022. Subjects were drawn from our institutional IAC-accredited noninterventional vascular laboratory database. Progression was defined as an increase in stenosis classification category. Imaging, demographic, and clinical data was obtained from our institutional electronic medical record via a database mining query. Cases were analyzed at the patient level, with severity corresponding to the greatest degree of ICA stenosis on the bilateral index and follow-up studies. Of 1954 unique patients imaged during the study period, 555 were followed with DUS for over 1 year. Table I summarizes demographic and historical factors for the entire cohort, stratified by availability of follow-up data. Patients with follow-up were more likely to have a history of stroke or transient ischemic attack were more likely to be taking antihypertensives, aspirin, statins, and P2Y12 inhibitors, and were more likely to undergo CEA or TCAR after diagnosis. They were less likely to have diabetes and chronic kidney disease. There were no differences in subsequent stroke or transient ischemic attack rates between groups. Of 555 followed patients, 55.3% at the index imaging study had moderate (50%-69%) stenosis, 34.6% had severe (70-99%) stenosis, and 10.1% had ICA occlusions. Patients were followed with DUS for a mean of 3.4 ± 1.8 years, with no significant difference in follow-up between stable and progressing patients. Mean time to progression was 2.2 ± 1.4 years. By the end of the follow-up period, 20.5% of followed patients experienced stenosis progression. Table II compares demographics, histories, and outcomes of stable vs progressing patients, grouped by initial stenosis severity. There were no significant differences between groups regarding comorbidities, medications, or procedure history. At diagnosis, 58.5% of stable patients and 64.9% of progressing patients were on best medical treatment (statin + antiplatelet agent) (P = .21). In both moderate and severe groups, stable patients underwent CEA more frequently than progressing patients. These results suggest that carotid disease progression occurs in a clinically significant portion of patients, affecting one-fifth of our cohort in an average of 26 months. No reliable factors emerged to predict progression or stroke in these patients. Less than two-thirds of these patients were found to be managed with best medical treatment, suggesting opportunities for further optimization.Table IPatient characteristicsDemographicsFollow-up (n = 555)No Follow-up (n = 1399)P valueMean age at diagnosis, years (range)72.9 (25-97)72.1 (18-105).12Female sex249 (44.9%)608 (43.5%).57Comorbidities Prior smoking277 (49.9%)663 (47.4%).32 Hypertension231 (41.6%)616 (44.0%).33 Hyperlipidemia217 (39.1%)601 (43.0%).12 Diabetes mellitus79 (14.2%)286 (20.4%).001 Coronary artery disease169 (30.5%)448 (32.0%).50 Myocardial infarction18 (3.2%)68 (4.9%).12 Chronic kidney disease79 (14.2%)286 (20.4%).001 Stroke or transient ischemic attack320 (57.7%)632 (45.2%).001 Vasculitis9 (1.6%)27 (1.9%).65 Head and neck cancer28 (5.0%)51 (3.6%).16Medications at diagnosis Antihypertensives393 (70.8%)882 (63.0%).001 Aspirin345 (62.2%)732 (52.3%)<.001 Statin392 (70.6%)893 (63.8%).004 P2Y12 inhibitor348 (62.7%)793 (56.7%).015 Anticoagulation54 (9.7%)148 (10.6%).58 Cilostazol15 (2.7%)27 (1.9%).29Procedure history Prior carotid endarterectomy10 (1.8%)29 (2.1%).70 Prior Transcarotid artery revascularization2 (0.4%)13 (0.9%).19 Prior transfemoral carotid stenting5 (0.9%)5 (0.4%).13Outcomes Subsequent CEA98 (17.7%)180 (12.9%).006 Subsequent transcarotid artery revascularization35 (6.3%)54 (3.9%).019 Subsequent transfemoral carotid stenting11 (2.0%)13 (0.9%).06 Subsequent cerebrovascular accident10 (1.8%)19 (1.4%).47 Subsequent transient ischemic attack2 (0.4%)5 (0.4%).99 Open table in a new tab Table IIComparison of stable and progressing patients, stratified by severityDemographicsModerate (50%-69%) StenosisSevere (70%-99%) StenosisP valueStable (n = 196)Progression (n = 111)Stable (n = 189)Progression (n = 3)Age at diagnosis.822Female sex92 (46.9%)49 (44.1%)84 (44.4%)2 (66.7%).832History Stroke or TIA108 (55.1%)72 (64.9%)113 (59.8%)2 (66.7%).402 Prior smoking96 (49.0%)62 (55.9%)91 (48.1%)1 (33.3%).533 Hypertension88 (44.9%)43 (38.7%)83 (43.9%)1 (33.3%).732 Hyperlipidemia81 (41.3%)46 (41.4%)77 (40.7%)0 (0.0%).551 Diabetes mellitus36 (18.4%)14 (12.6%)21 (11.1%)0 (0.0%).172 Chronic kidney disease36 (18.4%)14 (12.6%)21 (11.1%)0 (0.0%).172 Coronary artery disease73 (37.2%)35 (31.5%)48 (25.4%)0 (0.0%).054 Myocardial Infarction10 (5.1%)3 (2.7%)2 (1.1%)0 (0.0%).136 Vasculitis4 (2.0%)1 (0.9%)2 (1.1%)1 (33.3%)<.001a Head and neck cancer11 (5.6%)5 (4.5%)9 (4.8%)0 (0.0%).942Medications at diagnosis Antihypertensives144 (73.5%)84 (75.7%)137 (72.5%)2 (66.7%).93 Aspirin129 (65.8%)75 (67.6%)117 (61.9%)2 (66.7%).763 Statins143 (73.0%)85 (76.6%)139 (73.5%)1 (33.3%).383 P2Y12 inhibitors129 (65.8%)77 (69.4%)118 (62.4%)1 (33.3%).41 Anticoagulation19 (9.7%)11 (9.9%)19 (10.1%)0 (0.0%).952 Cilostazol6 (3.1%)4 (3.6%)3 (1.6%)0 (0.0%).694Procedure history CEA prior to diagnosis5 (2.6%)3 (2.7%)2 (1.1%)0 (0.0%).683 Transcarotid artery revascularization prior to diagnosis2 (1.0%)0 (0.0%)0 (0.0%)0 (0.0%).376 Transfemoral carotid stenting prior to diagnosis3 (1.5%)2 (1.8%)0 (0.0%)0 (0.0%).36Outcomes CEA after diagnosis38 (19.4%)11 (9.9%)45 (23.8%)0 (0.0%).023 Transcarotid artery revascularization after diagnosis12 (6.1%)8 (7.2%)13 (6.9%)0 (0.0%).946 Transfemoral carotid stenting after diagnosis1 (0.5%)3 (2.7%)5 (2.6%)1 (33.3%)<.001a Stroke after diagnosis2 (1.0%)1 (0.9%)3 (1.6%)1 (33.3%)<.001a Transient ischemic attack after diagnosis1 (0.5%)0 (0.0%)1 (0.5%)0 (0.0%).897aAnalysis limited by small sample size. 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