Outpatient parenteral inotropic therapy for advanced heart failure

Patients with advanced heart failure generally have hemodynamic perturbation characterized by low cardiac output and high ventricular filling pressures. This creates a clinical milieu with profound symptomatology that includes weakness, fatigue, and fluid-retention states causing peripheral edema, mesenteric congestion, and dyspnea syndromes. Great morbidity including hospital admissions and readmissions as well as high mortality rates ensue. Though medication and/or surgical intervention often attenuate heart failure symptomatology, morbidity, and mortality, some patients reach more advanced stages despite aggressive maneuvers. Indeed, patients presenting with acute decompensation of chronic congestive heart failure frequently receive parenteral inotropic drugs during their hospitalization with clinical improvement. Because these agents generally increase cardiac output and reduce pre-load and afterload, they can be lifesaving. Some patients, however, have symptomatic and hemodynamic rebound to worsened heart failure states during or shortly after inotrope weaning.

It was, then, a logical step to segue from acute inpatient inotrope infusion to long-term administration of these drugs in the outpatient setting when patients were dependent on these agents. Dopamine, dobutamine, and milrinone are all generally available inotropes that have been used singly or in combination in a chronic outpatient infusion setting.

Data from a few small clinical trials and anecdotal case experience suggest that these drugs result in both hemodynamic and clinical improvement that is generally sustained during chronic administration, and even noted long after discontinuation of infusions in some patients. Some reports have suggested that intermittent infusion therapy in outpatients (so-called pulsed therapy) is effective in attenuating congestive heart failure symptoms long term, with more data supporting chronic infusion of these agents. Though questions regarding safety of these agents have been raised, a reasonable compendium of data published to date supports the contention that inotropic drugs used in this fashion ameliorate symptoms. Legitimate concern may be raised regarding exacerbation of arrhythmias with subsequent sudden cardiac death syndrome; however, in severely symptomatic heart failure patients, the trade-off between symptomatic amelioration and the chance of sudden cardiac death may be worthwhile. Unfortunately, precise guidance regarding the best drug, dose, optimal administration technique, weaning protocol, and actual risk/benefit ratio are not well characterized. Practice as been guided, in large part, by anecdotal experience. However, it appears that chronic or pulsed outpatient parenteral inotropic infusion therapy is frequently prescribed and that this treatment option is an effective alternative for carefully selected patients with severely symptomatic and advanced heart failure. Formulating optimal protocols for home inotropic drug infusion therapy by conducting properly designed clinical trials will be an essential endeavor.