Longitudinal Changes in Arterial Properties in Cancer Patients: The Effect of Active Cancer and Treatment on Characteristic Impedance and Pulse Wave Velocity
Authors: Parr Shannon , Scheuermann Britton , Hammond Stephen , Ade Carl 
Published: May 2023

Background: Increased large artery stiffness (LAS) has been described in cancer patients through treatment and in the early phases of survivorship. To date, increases in LAS have been associated with cancer treatments themselves, as they disrupt vascular homeostasis both acutely and chronically. A consequence of LAS includes greater pulsatile energy transmission into the periphery, especially in the low-resistance vascular beds of the brain and kidney. We have recently shown that elevated levels of pulse pressure, an index of LAS, are associated with cardiovascular outcomes in cancer survivors. However, few studies have sought to determine if active malignancy alone influences arterial properties and if this contributes to the development of LAS. Purpose & Hypothesis: The primary purpose of this study was to determine the effect of malignancy on arterial properties. We calculated characteristic impedance (Zc), an index that is directly related to vessel wall stiffness, of the proximal aorta and the carotid artery. Impedance increases through the arterial tree, and as LAS develops, the impedance gradient dissipates, allowing for greater pulsatility into the periphery. We hypothesized that cancer patients (CP) would have greater aortic Zc when compared to non-cancer controls (CON). Secondly, we hypothesized CP would present with greater impedance matching (i.e., an aortic Zc that is more like carotid Zc when compared to CON. Methods: Newly diagnosed treatment naïve CP (n=5, 63.2±4.8y) and age, sex matched CON (n=5, 62.6±9.5y) were recruited for this study. Aortic and carotid characteristic impedance were calculated using pulse wave forms obtained via cardiac ultrasound system and resting blood pressure. Briefly, pulse wave images were taken at the common carotid artery and at the level of the aortic valve. Characteristic impedance was calculated as Zc=(Pi)/(Q95) where Pi is the incident blood pressure where blood flow reaches 95% of peak response (Q95). This calculation was performed for both the carotid artery and proximal aorta. Impedance matching was evaluated as the ratio between aortic Zc/carotid Zc. Differences between groups were assessed using paired t-test and statistical significance was considered at P<0.05. Results: Both aortic (CP 278.9±59.9 vs. CON 188.5±37.6 dyn·s/cm5; P=0.02) and carotid Zc (CP 8710±977.3 vs. CON 2024±469.4 dyn·s/cm5; P<0.001) were significantly greater in the CP when compared to CON. The impedance gradient was significantly lower in the CP when compared to CON (CP 0.03±0.01 vs. CON 0.09±0.02). Conclusions: Our data supports our first hypothesis that active malignancy alone alters arterial properties through increases in aortic and carotid Zc. However, our findings did not support our second hypothesis that cancer patients would have greater Zc matching as carotid Zc increased to a greater degree than aortic Zc. Taken together, our data suggests that malignancy alters arterial properties. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.