TY - JOUR

T1 - Cerebrovascular function is preserved during mild hyperthermia in cervical spinal cord injury

AU - Coombs, Geoff B

AU - Vucina, Diana

AU - Caldwell, Hannah G

AU - Barak, Otto F

AU - Mijacika, Tanja

AU - Lee, Amanda H X

AU - Sarafis, Zoe K

AU - Squair, Jordan W

AU - Krassioukov, Andrei V

AU - Phillips, Aaron A

AU - Dujic, Zeljko

AU - Ainslie, Philip N

PY - 2019/11

Y1 - 2019/11

N2 - STUDY DESIGN: Experimental study.OBJECTIVES: Compromised cerebrovascular function likely contributes to elevated neurological risk in spinal cord injury (SCI). Passive heating offers many cardiovascular and neurological health benefits; therefore, we aimed to determine the effects of an acute bout of heating on cerebrovascular function in chronic SCI.METHODS: Persons with cervical SCI (n = 15) and uninjured controls (CON; n = 15) completed 60 min of lower limb hot water immersion (40 °C). Assessments of middle cerebral (MCA) and posterior cerebral artery (PCA) velocities, pulsatilities, and neurovascular coupling (NVC) were performed using transcranial Doppler ultrasound. Duplex ultrasonography was used to index cerebral blood flow via the internal carotid artery (ICA), and carotid-femoral pulse-wave velocity (PWV) was measured using tonometry. The NVC response was quantified as the peak hyperemic value during 30-s cycles of visual stimulation.RESULTS: Mean arterial pressure changed differentially with heating [mean (standard deviation); SCI: +6(14) mmHg, CON: -8(12) mmHg; P = 0.01]. There were no differences in any intracranial artery measures (all P > 0.05), except for small (~10%) increases in MCA conductance in CON after heating vs. SCI (interaction P = 0.006). Resting ICA flow was greater in SCI vs. CON (P = 0.03) but did not change with heating in either group (interaction P = 0.34). There were also no between-group differences in the NVC response (ΔPCA conductance) pre- [SCI: 29(19)% vs. CON: 30(9)%] or post-heating [SCI 30(9)% vs. 25(9)%; interaction P = 0.22].CONCLUSIONS: Mild acute heating does not impair or improve cerebrovascular function in SCI or CON. Thus, further study of the effects of chronic heating interventions are warranted.

AB - STUDY DESIGN: Experimental study.OBJECTIVES: Compromised cerebrovascular function likely contributes to elevated neurological risk in spinal cord injury (SCI). Passive heating offers many cardiovascular and neurological health benefits; therefore, we aimed to determine the effects of an acute bout of heating on cerebrovascular function in chronic SCI.METHODS: Persons with cervical SCI (n = 15) and uninjured controls (CON; n = 15) completed 60 min of lower limb hot water immersion (40 °C). Assessments of middle cerebral (MCA) and posterior cerebral artery (PCA) velocities, pulsatilities, and neurovascular coupling (NVC) were performed using transcranial Doppler ultrasound. Duplex ultrasonography was used to index cerebral blood flow via the internal carotid artery (ICA), and carotid-femoral pulse-wave velocity (PWV) was measured using tonometry. The NVC response was quantified as the peak hyperemic value during 30-s cycles of visual stimulation.RESULTS: Mean arterial pressure changed differentially with heating [mean (standard deviation); SCI: +6(14) mmHg, CON: -8(12) mmHg; P = 0.01]. There were no differences in any intracranial artery measures (all P > 0.05), except for small (~10%) increases in MCA conductance in CON after heating vs. SCI (interaction P = 0.006). Resting ICA flow was greater in SCI vs. CON (P = 0.03) but did not change with heating in either group (interaction P = 0.34). There were also no between-group differences in the NVC response (ΔPCA conductance) pre- [SCI: 29(19)% vs. CON: 30(9)%] or post-heating [SCI 30(9)% vs. 25(9)%; interaction P = 0.22].CONCLUSIONS: Mild acute heating does not impair or improve cerebrovascular function in SCI or CON. Thus, further study of the effects of chronic heating interventions are warranted.

KW - Adult

KW - Cerebrovascular Circulation/physiology

KW - Cervical Vertebrae/diagnostic imaging

KW - Female

KW - Humans

KW - Hyperthermia, Induced/methods

KW - Male

KW - Middle Aged

KW - Spinal Cord Injuries/diagnostic imaging

U2 - 10.1038/s41393-019-0321-1

DO - 10.1038/s41393-019-0321-1

M3 - Article

C2 - 31289366

VL - 57

SP - 979

EP - 984

JO - Spinal cord

JF - Spinal cord

SN - 1362-4393

IS - 11

ER -