CLINICAL DECISION-MAKING BASED ON RADIONUCLIDE DETERMINED EJECTION FRACTION IN ONCOLOGY PATIENTS

Decreased left ventricular ejection fraction (LVEF) is a relative cont raindication for the use of potentially cardiotoxic chemotherapy. A re sting LVEF of 50% is usually used as the lower limit of normal values, The decision to change chemotherapy, however, is complex and is affec ted by many factors, including ejection fraction, Methods: To determin e how LVEF data were used by clinical oncologists in clinical decision making, we pet-formed a retrospective analysis of patients referred f or ejection fraction measurements from the hematology/oncology divisio ns of Stanford University from March 1992 through March 1995. The reco rds of 565 patients treated with potentially cardiotoxic chemotherapy were evaluated Results: LVEFs <50% were found in 153 patients The char ts of patients with reduced ejection fractions were reviewed to determ ine if the radionuclide measurement resulted in either discontinuation of the cardiotoxic agent or substitution of a less cardiotoxic drug o r mode of administration. These specific changes in therapy occurred i n only 43 of the 153 (28%) patients with Ejection fractions below 50%; 24 of the 43 (57%) had ejection fractions less than or equal to 40%. Patients with lower ejection fraction values were more likely to have their therapy changed than those with LVEFs close to normal. patients with ejection fractions less than or equal to 30 generally had cardiot oxic agents discontinued. Of patients who had a resting LVEF <50% and whose therapy was not changed, 81% had,normal increase in LVEF with ex ercise, Conclusion: In clinical practice at our institution, ejection fraction <50% is not used as an absolute contraindication to cardiotox ic chemotherapy. When the LVEF is less than 40%, potentially cardiotox ic therapy is most often discontinued or Omitted, Radionuclide evidenc e of cardiac reserve may account for decisions to continue cardiotoxic agents despite ejection fractions <50% in the majority of patients Fu rther study will be needed to establish standard criteria. Reserve fun ction, as measured by the change in ejection fraction from rest to str ess may be an important parameter used by oncologists to help select p atients for continued therapy in spite of a reduced ejection fraction, Our results argue that use of fixed criteria may be too restrictive.