RESUMEN
BACKGROUND: Adjuvant cancer treatments have been shown to decrease cardiac function. In addition to changes in cardiovascular risk, there are several additional functional consequences including decreases in exercise capacity and increased incidence of cancer-related fatigue. However, the effects of adjuvant cancer treatment on peripheral vascular function during exercise in cancer survivors have not been well documented. We investigated the vascular responses to exercise in cancer survivors previously treated with adjuvant cancer therapies. METHODS AND RESULTS: Peripheral vascular responses were investigated in 11 cancer survivors previously treated with adjuvant cancer therapies (age 58±6 years, 34±30 months from diagnosis) and 9 healthy controls group matched for age, sex, and maximal voluntary contraction. A dynamic handgrip exercise test at 20% maximal voluntary contraction was performed with simultaneous measurements of forearm blood flow and mean arterial pressure. Forearm vascular conductance was calculated from forearm blood flow and mean arterial pressure. Left ventricular ejection time index (LVETi) was derived from the arterial pressure wave form. Forearm blood flow was attenuated in cancer therapies compared to control at 20% maximal voluntary contraction (189.8±53.8 vs 247.9±80.3 mL·min-1, respectively). Forearm vascular conductance was not different between groups at rest or during exercise. Mean arterial pressure response to exercise was attenuated in cancer therapies compared to controls (107.8±10.8 vs 119.2±16.2 mm Hg). LEVTi was lower in cancer therapies compared to controls. CONCLUSIONS: These data suggest an attenuated exercise blood flow response in cancer survivors ≈34 months following adjuvant cancer therapy that may be attributed to an attenuated increase in mean arterial pressure.
Asunto(s)
Velocidad del Flujo Sanguíneo/fisiología , Presión Sanguínea/fisiología , Terapia por Ejercicio/métodos , Hipertensión/prevención & control , Contracción Muscular/fisiología , Músculo Esquelético/fisiopatología , Neoplasias/terapia , Anciano , Supervivientes de Cáncer , Estudios de Casos y Controles , Quimioterapia Adyuvante , Estudios Transversales , Ejercicio Físico/fisiología , Femenino , Humanos , Hipertensión/etiología , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad , Neoplasias/complicaciones , Neoplasias/fisiopatología , Radioterapia AdyuvanteRESUMEN
The cardiotoxic effects of adjuvant cancer treatments (i.e., chemotherapy and radiation treatment) have been well documented, but the effects on peripheral cardiovascular function are still unclear. We hypothesized that cancer survivors i) would have decreased resting endothelial function; and ii) altered muscle deoxygenation response during moderate intensity cycling exercise compared to cancer-free controls. A total of 8 cancer survivors (~70 months post-treatment) and 9 healthy controls completed a brachial artery FMD test, an index of endothelial-dependent dilation, followed by an incremental exercise test up to the ventilatory threshold (VT) on a cycle ergometer during which pulmonary VÌO2 and changes in near-infrared spectroscopy (NIRS)-derived microvascular tissue oxygenation (TOI), total hemoglobin concentration ([Hb]total), and muscle deoxygenation ([HHb] ≈ fractional O2 extraction) were measured. There were no significant differences in age, height, weight, and resting blood pressure between cancer survivors and control participants. Brachial artery FMD was similar between groups (P = 0.98). During exercise at the VT, TOI was similar between groups, but [Hb]total and [HHb] were significantly decreased in cancer survivors compared to controls (P < 0.01) The rate of change for TOI (ΔTOIΔ/VÌO2) and [HHb] (Δ[HHb]/ΔVÌO2) relative to ΔVÌO2 were decreased in cancer survivors compared to controls (P = 0.02 and P = 0.03 respectively). In cancer survivors, a decreased skeletal muscle microvascular function was observed during moderate intensity cycling exercise. These data suggest that adjuvant cancer therapies have an effect on the integrated relationship between O2 extraction, VÌO2 and O2 delivery during exercise.
Asunto(s)
Endotelio Vascular/fisiopatología , Músculo Esquelético/irrigación sanguínea , Neoplasias/fisiopatología , Neoplasias/terapia , Oxígeno/sangre , Adulto , Quimioterapia Adyuvante , Prueba de Esfuerzo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/fisiopatología , Neoplasias/tratamiento farmacológico , Neoplasias/radioterapia , Consumo de Oxígeno/fisiología , Radioterapia Adyuvante , Espectroscopía Infrarroja Corta , SobrevivientesRESUMEN
Shear rate can elicit substantial adaptations to vascular endothelial function. Recent studies indicate that prior exposure to anterograde flow and shear increases endothelium-dependent flow-mediated dilation at rest and that anterograde shear can create an anti-atherosclerotic and provasodilatory state. The primary aim of the present study was therefore to determine the effects of prior exposure to anterograde shear on exercise-induced brachial artery dilation, total forearm blood flow (FBF), and vascular conductance (FVC) during dynamic handgrip exercise. Eight men completed a constant-load exercise test corresponding to 10% maximal voluntary contraction, prior to (baseline) and following a 40 min shear rate intervention (post-SRI) achieved via unilateral forearm heating, which has previously been shown to increase anterograde shear rate in the brachial artery. During the SRI, anterograde shear rate increased 60.9 ± 29.2 sec(-1) above baseline (P < 0.05). Post-SRI, the exercise-induced brachial artery vasodilation was significantly increased compared to baseline (4.1 ± 0.7 vs. 4.3 ± 0.6 mm, P < 0.05). Post-SRI FBF mean response time (33.2 ± 16.0 vs. 23.0 ± 11.8 sec, P < 0.05) and FVC mean response time (31.1 ± 12.8 20.2 ± 10.7 sec, P < 0.05) at exercise onset were accelerated compared to baseline. These findings demonstrate that prior exposure to anterograde shear rate increases the vascular responses to exercise and supports the possible beneficial effects of anterograde shear rate in vivo.