1. Sinus reaction during carotid stenting according to the carotid lesion type Jong Lim Kim, Dae Chul Suh, Jin-Ho Shin, Dong Ho Hyun, Ha Young Lee, Deok Hee Lee, Choong Gon Choi, Sang Joon Kim, Jong Sung Kim Departments of Radiology and Research Institute of Radiology, Department of Neurology, University of Ulsan, College of Medicine, Asan Medical Center, Korea

2. Carotid sinus reaction or hemodynamic instability · Carotid sinus reaction Post- and peri-procedural hypotension (SBP <90 mmHg) Bradycardia (HR <50 beats/sec) Heart rate fluctuation (>20 beats/sec) * Asystole (≥ 3 sec) and hypotension (SBP ≤ 90 mm Hg) Leisch F, et al. Catheter Cardiovasc Interv. 2003 * Hypotension (SBP < 90 mm Hg) or bradycardia (HR < 60 beats/min) Gupta R, et al. J Am Coll Cardiol. 2006

3. Carotid sinus reaction during carotid artery stenting Carotid sinus reaction occurs frequently (40%) during carotid sinus stent Bifurcation location of stenosis is the most important predictor of carotid sinus reaction * Carotid sinus reaction Asystole (≥ 3 sec) Hypotension (SBP ≤ 90 mmHg) * Carotid stenosis location Bifurcation Ostial Isolated ICA Leisch F, et al. Catheter Cardiovasc Interv. 2003

4. Carotid sinus reaction during carotid artery stenting Hemodynamic disturbances was not related to carotid stenosis location * Hemodynamic disturbances Hypotension (SBP < 90 mmHg) Bradycardia (HR < 50 beats/min) Heart rate fluctuation (> 20 beats/min) Hypertension (SBP > 160 mmHg) * Carotid stenosis location Apical Body Park ST, et al. Am J Neuroradiol. 2010

5. I like to show that carotid sinus reaction can be associated with stenosis location Apical type stenosis in the left carotid bulb No carotid sinus reaction Body type stenosis in the right carotid bulb Marked carotid sinus reaction

6. Carotid sinus (anatomy & physiology) · Ill-defined dilatation at the origin of the internal carotid artery D Heath. Thorax. 1983 · Monitoring and regulation of blood pressure Michael Doumas, et al. Expert Opin. Ther. Targets. 2009

7. Carotid sinus (Embryology) Common carotid artery and proximal part of internal carotid artery - Formed by remodeling of the third arch artery (yellow) Baroreceptors (arrow) of the glossopharyngeal nerve - Distributed in proximal portion of internal carotid artery (carotid sinus) Yoko Kameda. Cell Tissue Res. 2009

8. Carotid sinus nerve · Originating from the glossopharyngeal (IX) nerve · Located in loose tissue close to the ICA wall Run parallel to or together with vagus nerve · Ended in both carotid sinus & carotid body Toorop RJ, et al. J Vasc Surg. 2009 IX, glossopharyngeal nerve X, vagus nerve P, pharyngeal branches S, sympathetic trunk

9. Baroreflex · Major contributor to the homeostatic system of blood pressure control Michael Doumas, et al. Expert Opin. Ther. Targets. 2009 · Afferent fibres from carotid sinus baroreceptors join the glossopharyngeal nerve and project to the nucleus tractus solitarii in the dorsal medulla, and in turn projects to efferent cardiovascular neurones in the medulla and spinal cord Timmers HJ et al. J Physiol. 2003 Arterial baroreflex loops Carotid sinus baroreceptors → glossopharyngeal nerve → medullary centres (nucleus tractus solitarii) → sympathetic and parasympathetic fibres to heart and blood vessels

10. Materials and Methods Prospective analysis 2007.01 ~ 2009.6 95 patients who underwent carotid stenting M : F = 82 : 12 Mean age : 69 years (38-89 years) Symptomatic carotid stenosis ≥ 50% (NASCET criteria)

11. Materials and Methods Transient sinus reaction : <3 hours Delayed sinus reaction : 3~24 hours Analyzed angiographic or neurointerventional findings - Location of plaque : apical vs. body - Length of maximum stenosis from the ICA ostium - Lesion length - Stenosis degree - Calcification - Balloon diameter - Balloon pressure - Stent length - Residual stenosis - Hyperperfusion - Restenosis

12. Results <3hr SR(+)<3hr SR(-)P-valve Lesion type Apical749 0.001 Body1623 Lesion length16.7718.300.26 Length of maximum stenosis fr om the ICA ostium* 7.7412.790.004 Stenosis degree75.8774.040.968 Calcification (yes)6150.577 Balloon diameter (mm)5.235.370.283 Balloon pressure (ATM)8.008.290.464 Stent length34.3534.030.728 Residual stenosis23.5219.860.295 Comparison of Significant Difference of Transient Sinus Reaction * Stepwise logistic regression to eliminate confounding factor reveals that length is true independent factor (P = 0.002)

13. Results Apical (n=56)Body (n=39)P-valve SBP>160 < 3 h1280.914 3 - 24 h751 Event 1m500.076 6m010.411 Hyperperfusion620.464 Restenosis130.302

14. Case 1 Age/sexM/63 Locationright Transient sinus reaction+ Lesion typeBody Length of maximum stenosis from th e ICA ostium* (mm) 2.24

15. Case 2 Age/sexM/77 Locationright Transient sinus reaction- Lesion typeApical Length of maximum stenosis from th e ICA ostium* (mm) 14.53

16. Case 3 Age/sexM/85 Locationright Transient sinus reaction- Lesion typeApical Length of maximum stenosis from t he ICA ostium* (mm) 16.67 Hyperperfusion+

17. Summary and conclusion 1. Sinus reaction in carotid stenting is different in two distinct locations, body and apical portion of carotid bulb 2. Body lesion type was more vulnerable to sinus reaction than apical lesion type ① Related to anatomical baroreceptor disposition in carotid sinus * Baroreceptors are located in the carotid sinus of carotid bulb Such embryological implication appeared to affect carotid bulb lesion type ② Induced preventive effect for high blood pressure which might contribute to hyperperfusion syndrome → Less common to hyperperfusion syndrome 3. Apical lesion type had higher event rate than body lesion type ① Associated with more common periprocedural hypertension → Needs more careful management of blood pressure control for apical lesion type after carotid stenting