Background: Milrinone is a phosphodiesterase III inhibitor that is used in patients with acute or chronic heart failures and pulmonary hypertension. It is often used in cardiac surgeries requiring cardiac support such as CABG surgery and cardiac transplantation. Its approved indications include acute decompensated heart failure with reduced ejection fraction in need of inotropic support. The use of milrinone in the outpatient setting is generally limited to patients with severe symptoms of congestive heart failure refractory to optimal medical therapy. In the myocardium, PDE III inhibition leads to increased contractility and improved relaxation which improves systolic and diastolic function, optimizing cardiac output. In the vasculature, PDE III inhibition prevents cGMP metabolism in the smooth musculature and results in vasodilation in both arteries and veins. Milrinone can have fatal adverse effects and requires continuous monitoring. Milrinone has the potential to induce hemodynamic changes and arrhythmias. These effects do not follow a dose-dependent relationship. Also, milrinone can also cause an increase in venous vessel capacitance, leading to decreased preload and resulting in symptoms such as headaches, syncopes and severe hypotension.
Purpose: The purpose of this study is to evaluate clinical efficacy of continuous milrinone infusion in home settings by monitoring periodic assessments for side effects, patient overall condition and feedback. This study will examine currently active and discharged patients on milrinone at this home infusion pharmacy.
Methods: Retrospective analysis of the electronic medical records of the current and discharged patients on milrinone at this home infusion company was performed. Data was obtained from the electronic medical records. Inclusion criteria include patients who are of age 18 or older, who had peripheral/ central venous catheters or ports and were administered at least one dose of milrinone. Exclusion criteria included pediatrics, patients with no catheter access information and patients canceled from the service prior to administration of the first dose. Data from resources such as monthly assessments conducted for chronic patients on service for at least one month and weekly inotropic assessments were used to identify common adverse effects. Factors such as any side effects, changes in weight, presence of edema, shortness of breath, recent heart rate and blood pressure were used to evaluate safety and efficacy of milrinone treatment in a diverse yet specific patient population. Weekly labs conducted to monitor patients while on service were obtained to compare results and to identify a trend of abnormal lab values if any present. Weekly nursing visits were also used as a monitoring parameter for any noticeable changes in patients’ conditions. Results: This study demonstrated that milrinone infusions can be safely administered in home settings as 21 patients safely received one or more infusions from 9/4/2020 to 11/15/22. 18 of 21 patients (85.7%) have at least once mentioned during the weekly or monthly assessment that milrinone therapy has helped or improved their ADLs (activities of daily living). 13 patients have had at least one hospitalization while on service, and of the total 19 hospitalizations, 8 (42.1%) were related and 11 (57.9%) were unrelated to therapy. 7 patients (33.3%) reported no adverse events or lab abnormalities during duration of service. Of the adverse events reported during weekly and monthly assessments, shortness of breath was the most common with 24 incidences, followed by lab abnormality (16), edema (11), chest pain (9), changes to urine output (4), significant weight change defined by greater than 3 lbs (4) and fatigue (3). The 15 inactive patients were discharged with various reasons related (3) and non-related (12) to therapy. Such reasons include hospitalizations, rehab admission, transfer to a different branch and lack of response from the patient. Discussion: Although the study shows that milrinone can be safely administered in home settings, a potential limitation is that this study lacks in sample size and would require additional trials with larger populations to further demonstrate safety and efficacy of milrinone in home settings. Additional studies are necessary to validate the safety and efficacy of milrinone in home settings for future uses. Also, adverse reactions could have been underreported as 7 patients have reported no side effects while they were on service. Conclusions: In conclusion, this study has shown that milrinone is generally safe to administer in home settings as most patients are continuing the infusion with no major side effects/ significant lab abnormalities or are discharged with reasons unrelated to the therapy. Overall, most patients have tolerated the therapy well with minimal adverse reactions.