Patient Attributes Associated With Better Long-Term Outcomes on Palliative Milrinone

Abstract

Milrinone is a phosphodiesterase three inhibitor used as an inotrope in patients with advanced heart failure with reduced ejection fraction (HFrEF). Its action is independent of beta-receptor stimulation, which makes it preferable in patients who are on beta blockers as part of a guideline-directed neurohormonal blockade. There have been numerous studies evaluating the risks, benefits, and mortality associated with milrinone in the management of chronic heart failure patients. Time and again, there has been concern regarding the undesirable outcomes associated with it, including higher mortality and cardiac arrhythmias. Additionally, it has been difficult to determine whether milrinone or disease progression is responsible for adverse outcomes and mortality. In light of such discrepancy, the selection of patients for milrinone remains challenging. We hypothesized that there are underlying patient characteristics that influence the response to milrinone and may predict milrinone's adverse outcomes in spite of milrinone. A retrospective study review of 10 patients on palliative milrinone was conducted to identify these factors with a mean follow-up of 36 months. During the study period, four of 10 patients died. These four patients were on milrinone for a mean of 11.5 months. The attributes of the survivors compared to the deceased included lower age at start of therapy (67.5 vs 79 y), female gender (66% vs 33%), non-ischemic cardiomyopathy (33% vs 50%), associated diagnosis of atrial fibrillation/flutter(50% vs 25%), hyperlipidemia (66% vs 50%), or anemia (83% vs 75%), presence of chronic resynchronization therapy (CRT) (66% vs 25%), and implantable cardioverter-defibrillator (ICD) (16% vs 0%), as well as lower sodium (136 vs 140 mEq), chloride (101.5 vs 104.5 mEq), potassium (4.07 vs 4.23 mEq), and creatinine (1.3 vs 1.8 mg/dL) Conversely, the deceased patients were more likely to have coronary artery disease (75% vs 33%), diabetes mellitus (50% vs 16%), hypertension (100% vs 83%), chronic kidney disease (75% vs 66%), peripheral vascular disease (25% vs zero), higher pulmonary artery pressures (54 vs 50.5%), and history of percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) (50% vs 16%). These trends exhibit patient characteristics that may predict better outcomes on long-term milrinone although larger studies are needed to assess the statistical significance of these findings.