Cardiac baroreflex dysfunction in patients with pulmonary arterial hypertension at rest and during orthostatic stress: role of the peripheral chemoreflex

Author(s):Show less -

Paula-Ribeiro, Marcelle ^{[1, 2]} ; Ribeiro, Indyanara C. ^{[1, 3, 4]} ; Aranda, Liliane C. ^{[1, 3, 4]} ; Silva, Talita M. ^{[1, 3, 4]} ; Costa, Camila M. ^{[3, 4]} ; Ramos, Roberta P. ^{[3, 4]} ; Ota-Arakaki, Jaquelina ^{[3, 4]} ; Cravo, Sergio L. ^[1] ; Nery, Luiz E. ^{[3, 4]} ; Stickland, Michael K. ^[5] ; Silva, Bruno M. ^{[1, 2, 3, 4]}

Affiliation

^[1] Fed Univ Sao Paulo UNIFESP, Dept Physiol, Sao Paulo - Brazil

^[2] Fed Univ Sao Paulo UNIFESP, Dept Med, Postgrad Program Translat Med, Sao Paulo - Brazil

^[3] Fed Univ Sao Paulo UNIFESP, Div Resp Med, Postgrad Program Pulm Med, Sao Paulo - Brazil

^[4] Fed Univ Sao Paulo UNIFESP, Div Resp Med, Pulm Vasc Grp, Sao Paulo - Brazil

^[5] Univ Alberta, Div Pulm Med, Edmonton, AB - Canada

• Document type: Journal article
• Source: Journal of Applied Physiology; v. 131, n. 2, p. 794-807, AUG 2021.
• Web of Science Citations: 0

Abstract

The baroreflex integrity in early-stage pulmonary arterial hypertension (PAH) remains uninvestigated. A potential baroreflex impairment could be functionally relevant and possibly mediated by enhanced peripheral chemoreflex activity. Thus, we investigated 1) the cardiac baroreflex in nonhypoxemic PAH; 2) the association between baroreflex indexes and peak aerobic capacity {[}i.e., peak oxygen consumption ((V) over dotO(2peak))]; and 3) the peripheral chemoreflex contribution to the cardiac baroreflex. Nineteen patients and 13 age- and sex-matched healthy adults (HA) randomly inhaled either 100% O-2 (peripheral chemoreceptor inhibition) or 21% O-2 (control session) while at rest and during a repeated sit-to-stand maneuver. Beat-by-beat analysis of R-R intervals and systolic blood pressure provided indexes of cardiac baroreflex sensitivity (cBRS) and effectiveness (cBEI). The PAH group had lower cBEI for all sequences (cBEI(ALL)) at rest {[}means +/- SD: PAH =0.5 +/- 0.2 vs. HA =0.7 +/- 0.1 arbitrary units (a.u.), P = 0.02] and lower cBRS(ALL) (PAH = 6.8 +/- 7.0 vs. HA=9.7 +/- 5.0 ms.mmH(-1), P < 0.01) and cBEI(ALL) (PAH=0.4 +/- 0.2 vs. HA= 0.6 +/- 0.1 a.u., P < 0.01) during the sit-to-stand maneuver versus the HA group. The cBEI during the sit-to-stand maneuver was independently correlated to (V) over dotO(2peak) (partial r= 0.45, P < 0.01). Hyperoxia increased cBRS and cBEI similarly in both groups at rest and during the sitto-stand maneuver. Therefore, cardiac baroreflex dysfunction was observed under spontaneous and, most notably, provoked blood pressure fluctuations in nonhypoxemic PAH, was not influenced by the peripheral chemoreflex, and was associated with lower (V) over dotO(2peak), suggesting that it could be functionally relevant. NEW \& NOTEWORTHY Does the peripheral chemoreflex play a role in cardiac baroreflex dysfunction in patients with pulmonary arterial hypertension (PAH)? Here we provide new evidence of cardiac baroreflex dysfunction under spontaneous and, most notably, provoked blood pressure fluctuations in patients with nonhypoxemic PAH. Importantly, impaired cardiac baroreflex effectiveness during provoked blood pressure fluctuations was independently associated with poorer functional capacity. Finally, our results indicated that the peripheral chemoreflex did not mediate cardiac baroreflex dysfunction among those patients. (AU)

• FAPESP's process: 16/01155-6 - Cardiorespiratory responses mediated by the interaction between the peripheral chemoreflex and the muscle mechanoreflex in healthy humans
• Grantee: Talita Miranda Silva
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 15/22198-2 - Tonic contribution of the peripheral chemoreflex to vagal control of the heart at rest, Orthostatism and recovery from exercise in patients with pulmonary arterial hypertension
• Grantee: Marcelle de Paula Ribeiro
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 16/23622-5 - The contribution of peripheral chemoreflex to the vagal control of the heart during recovery from exercise in healthy subjects
• Grantee: Indyanara Cristina Ribeiro
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 14/24294-6 - Tonic contribution of the peripheral chemoreflex to the vagal control of the heart at rest and recovery from exercise in patients with chronic heart failure
• Grantee: Bruno Moreira Silva
• Support Opportunities: Regular Research Grants