IIIB or not IIIB: a previously unanswered question.

The term New York Heart Association (NYHA) class IIIB has been used increasingly in clinical medicine, including as an inclusion criteria for many clinical trials assessing left ventricular assist devices (LVADs). Indeed, NYHA class IIIB is incorporated in the Food and Drug Administration's approved indication for the Heartmate II. However, on review of the medical literature, we found that there is no consensus definition of NYHA class IIIB. Until the ambiguity is resolved, we suggest that this designation not be used in clinical practice or by investigators leading clinical trials assessing therapies which convey substantial risk to patients and therefore require clarity in describing the enrolled patient population. With ongoing improvements in LVADs, this therapy will increasingly be considered in patients less sick than those who require inotropic support, providing urgency to establish a consensus system of classifying such patients who nevertheless fall within the spectrum of advanced heart failure. Herein we propose a modification of the standard NYHA classification system which can be used to fill this void.