Determining Patient Characteristics Leading to Worse Outcomes with Long Term Milrinone Therapy

Abstract

Background Milrinone is an inotrope used in patients with end-stage heart failure awaiting mechanical support, heart transplant or as palliative therapy. Numerous studies have evaluated adverse events and mortality associated with milrinone use, which have shown to be associated with higher mortality rates and arrhythmias. Despite the homogeneous prevalence of these adverse effects, the association of their development with the duration of treatment remains debatable. Additionally, emerging smaller studies have described relative safety of long term milrinone use. In light of such discrepancy, no specific factors have been identified to account for the difference in onset and prevalence of milrinone associated deleterious effects. We sought to determine underlying patient characteristics that would influence worse outcomes with milrinone Methods We conducted a single-center retrospective study reviewing all patients on outpatient milrinone therapy at St. Francis Hospital with a mean follow up of 36 months. Results In total, 10 patients were identified of which 4 patients were deceased. These 4 patients were on milrinone for a mean of 11.5 months. The attributes of the survivors compared to deceased showed: age at start of therapy 67.5 vs 79; female gender 66% vs 33%; non-ischemic cardiomyopathy 33% vs 50%; atrial fibrillation/flutter 50% vs 25%; hyperlipidemia 66% vs 50%; anemia 83% vs 75%; presence of CRT 66% vs 25% and ICD 16% vs 0%; sodium 136 vs 140mEq; chloride 101.5 vs 104.5mEq; potassium 4.07 vs 4.23mEq; and creatinine 1.3 vs 1.8 mg/dL. Conversely, deceased patients were more likely to have diabetes (50% vs 16%), hypertension (100% vs 83%), chronic kidney disease (75% vs 66%), peripheral vascular disease (25% vs 0%), coronary artery disease (75% vs 33%), higher pulmonary artery pressures (54 vs 50.5mmHg) and history of coronary intervention with primary coronary angioplasty or coronary bypass surgery (50% vs 16%). Conclusion Males were more likely to have died if they were placed on milrinone at a later age. Ischemic risk factors appear to be more deleterious. These trends exhibit potential patient characteristics that may predict worse outcomes on long term milrinone. Larger studies are needed to assess statistical significance of these findings.