5-Fluorouracil induces arterial vasocontractions.

BACKGROUND: From 2% to 10% of cancer patients treated with 5-fluorouracil (5-FU) will develop symptomatic cardiotoxicity. Nevertheless, the underlying pathophysiology is mostly unknown. PATIENTS AND METHODS: We investigated the influence of intravenous chemotherapy (CTX) on the diameter of the brachial artery using high resolution ultrasound in patients with malignant tumors, mostly gastrointestinal cancer. Cytostatic drugs included 30 cases with 5-FU and 30 cases with non-5-FU CTX (cis/carboplatin, anthracycline and cyclophosphamide). In addition, plasma levels of big endothelin were assessed prior to and after CTX.
RESULTS: Fifteen of 30 patients (50%) showed a contraction of the brachial artery after the end of 5-FU application (median 11%, range 4.3-18.5), whereas no single contraction was noticed in 30 patients following non-5-FU-based CTX. Vessel tonus generally normalized within 30 min after stopping 5-FU. Five patients positive for 5-FU associated vessel contraction were repeatedly exposed to 5-FU. Vessel contractions reoccurred in 86% (18/21) of these administrations. When patients with 5-FU bolus application were pre-treated with glyceroltrinitrate no contraction of the brachial artery was detected in five out of five occasions. There was a trend towards increased big endothelin plasma levels after 5-FU application (median 1.52 versus 1.99 fmol/ml; P = 0.07), whereas big endothelin levels remained unchanged after non-5-FU CTX (1.83 versus 1.83 fmol/ml; P = 0.99).
CONCLUSIONS: Application of 5-FU is commonly accompanied by arterial vessel contractions, which is likely to represent the first step in 5-FU-induced cardiotoxicity. 5-FU-associated vessel contractions were highly reproducible on re-exposure and were in the case of bolus application completely preventable by glyceroltrinitrate.