Relationship between carotid atherosclerotic plaque characteristics in magnetic resonance imaging and perioperative hemodynamic instability

Abstract

Objective: To analyze the relationship between carotid atherosclerotic plaque characteristics in magnetic resonance imaging (MRI) and perioperative hemodynamic instability in patients with severe carotid artery stenosis undergoing carotid artery stenting (CAS). Methods: A total of 89 patients with carotid artery stenosis who underwent CAS treatment at Beijing Tsinghua Changgung Hospital affiliated to Tsinghua University from January 1, 2017, to December 31, 2021, were prospectively included. Among them, 74 were male and 15 were female, with an age range of 43 to 87 years (mean age: 67.8±8.2 years). Preoperative examinations included carotid artery MRI vessel wall imaging to analyze the existence of large lipid-rich necrotic core (LRNC), intraplaque hemorrhage (IPH), and fibrous cap rupture in carotid artery plaques. Plaques without the above-mentioned risk factors were defined as stable plaque group (34 cases), while those with such risk factors were defined as vulnerable plaque group (55 cases). The number of risk factors present in each plaque was also calculated. Intraoperative changes in blood pressure and heart rate were recorded, and the use of dopamine postoperatively was noted. Using the risk factors that the plaque has as independent variables and the clinical outcomes as dependent variables, the RR values were calculated, and the differences in clinical outcomes of patients with different risk factors were compared. Results: The incidence rates of hypotension and bradycardia were higher in patients with vulnerable plaques than those with stable plaques (60.0% (33/55) vs 14.7%(5/34) and 38.2%(21/55) vs 14.7%(5/34), respectively; both P<0.05). Based on MRI imaging features, the large LRNC was present in 45 cases, with RR values for hypotension and bradycardia of 3.15 (1.69-5.87) and 2.20 (1.07-4.53), respectively; IPH was present in 37 cases, with RR values for hypotension and bradycardia of 2.70 (1.61-4.55) and 2.25 (1.15-4.39), respectively; and fibrous cap rupture was present in 29 cases, with RR values for hypotension and bradycardia of 1.50 (0.94-2.40) and 1.29 (0.67-2.49), respectively. The higher the number of risk factors in vulnerable plaques, the higher the incidence of intraoperative blood pressure and heart rate decrease: when the number of risk factors ranged from 0 to 3, the incidence of blood pressure decrease was 14.7% (5/34), 9/18, 11/18, and 13/19, respectively (P<0.001), and the incidence of heart rate decrease was 14.7% (5/34), 6/18, 7/18, and 8/19, respectively (P=0.022). There was no significant difference in the number of cases of dopamine use between the two groups (P>0.05). Conclusion: Patients with a higher number of risk factors for vulnerable carotid plaques, as indicated by carotid artery MRI vessel wall imaging, are at a higher risk of experiencing blood pressure and heart rate decrease during CAS surgery.