Renal Arterial Resistance Index in Patients With Colorectal Cancer Treated With Fluoropyrimidines

Background Fluoropyrimidines are the most commonly used drugs in the treatment of colorectal tumors. The fluoropyrimidine–related cardiotoxicity remains a major clinical problem. Purpose The aim of this study was to evaluate the relationship between cardiotoxicity (CT) and Renal arterial Resistance Index (RRI) as marker of renal perfusion. Methods One hundred and two outpatients with a first diagnosis of localized or metastatic colorectal cancer were consecutively enrolled. The patients underwent a cardiological evaluation before the beginning of chemotherapy regimen containing fluoropyrimidines. All patients underwent: a clinical evaluation; a routine bloodchemistry to evaluate glomerular filtration rate (GFR) by creatinine (MDRD formula); a blood sample (approximately 3 mL) collected in EDTA–stabilized tubes, according to standard clinical practice, for genetic analysis of variants in fluoropyrimid in metabolism genes known to be associated with cardiotoxicity risk; a transthoracic echocardiogram to assess left ventricular ejection fraction (LVEF) and estimate central venous pressure; a renal echo–Doppler in order to evaluate RRI. Peak systolic and end–diastolic velocity of segmental renal artery was obtained by pulsed Doppler flow and RRI was subsequentely calculated. Results The overall mean age was 68±10 years. Of the 108 patients included in the study, 49(48%) were male and 51(52%) were female. In the studied population we observed a mean RRI equal to 0.625±0.081 at baseline assessment. We found a statistically significant inverse correlation between RRI and baseline GFR (Pearson r=−0.272, p=0.030). Thirty-one patients completed the one–year follow–up. Among them, 30% experienced a significant increase in blood pressure; Additionally, acute coronary syndromes requiring revascularization and hospitalizations for heart failure were observed in 6% and 8% of patients, respectively. Figure shows RRI mean values with 95% confidence interval at baseline and at each follow–up by occurrence of hypertension and cardiac events (panel A and B). Although RRI seems higher in patients with events during follow–up, no significant association was detected. Conclusions Integrating RRI assessment with fluoropyrimidin e metabolic profiling may enhance the identification of patients at increased risk of cardiotoxicity. Further studies will be needed to clarify the role of the renal resistive index in this setting.