Targeting of dobutamine to ischemic myocardium without systemic effects by selective suction and pressure-regulated retroinfusion.

Abstract

To study the effects of low-dose dobutamine and/or glyceryl trinitrate in addition to selective suction and pressure-regulated retroinfusion with arterial blood on regional myocardial function of the ischemic myocardium and systemic hemodynamics. Using a pig model of repeated brief (90 s) occlusions of the left anterior descending artery, selective suction and pressure-regulated retroinfusion was carried out either with arterial blood alone (SSRalone) or with arterial blood and simultaneous application of low-dose dobutamine (0.1 microgram/kg/min (SSRDOB), glyceryl trinitrate (0.03 mg/kg/min) (SSRNIT) or the combination of both drugs (SSRDOB + NIT). Regional myocardial function of the ischemic and non-ischemic myocardium was determined by sonomicrometry (segment shortening). Segment shortening in the ischemic area after 90 s of ischemia was preserved at 57.5 +/- 9.2% with SSRalone but at 78.0 +/- 22.3% of baseline with SSRDOB (P < 0.05). The addition of glyceryl trinitrate did not improve regional myocardial function further. No effects of locally applied dobutamine were observed with regard to non-ischemic myocardium or heart rate. Cardiac output and mean arterial blood pressures tended to be further stabilized with SSRDOB. Local application of low-dose dobutamine together with arterial blood by selective suction and pressure-regulated retroinfusion during brief myocardial ischemia resulted in improved regional myocardial function without undesired effects on non-ischemic myocardium or systemic hemodynamics.