Thorac Cardiovasc Surg 2005; 53 - MP57
DOI: 10.1055/s-2005-862103

The Na+/H+ exchange inhibitor cariporide is washed out from the myocardium by crystalloid cardioplegia

M Bechtel 1, W Eichler 2, B Weidtmann 3, K Törber 1, M Hernandez 2, K Klotz 2, H Sievers 1, C Bartels 1
  • 1Universität zu Lübeck, Klinik für Herzchirurgie, Lübeck
  • 2Universität zu Lübeck, Abt. für Anästhesiologie, Lübeck
  • 3Universität zu Lübeck, Medizinische Klinik II, Lübeck

Objectives: Experimentally, inhibition of the Na+/H+-exchanger [NHE] has been shown to be cardioprotective. However, a clinical benefit could not be demonstrated unequivocally, most likely because of difficulties to deliver the correct dose of NHE-inhibitor at the right time. Whether the infusion of cardioplegic solutions has the potential to affect the myocardial concentration of NHE-inhibitors has not been evaluated so far.

Material and Methods: a) 3 pigs received an iv-bolus (180mg) of the NHE-inhibitor cariporide and were sacrified shortly thereafter for measurement of the myocardial cariporide-concentration.

b) 10 pigs were randomized to receive either cariporide (iv-bolus followed by an infusion of 40mg/h) or placebo. Cardiopulmonary bypass was initiated, and the heart was arrested for 60 minutes by repeated infusion of St-Thomas solution. LV-function was studied using microsonometry. Myocardial damage was assessed by measurements of myoglobin, troponin T, lactate and pH in the coronary sinus. Serum concentrations of cariporide were measured throughout the study, and myocardial concentrations were measured before the end of cardioplegic arrest and 3 hours thereafter.

Results: a) Cariporide was present in all myocardial specimens (1.4±0.7 ng/mg).

b) Neither LV-function nor myocardial damage did differ significantly between the groups at any time point. Stable serum cariporide-concentrations (0.79±0.29µg/ml) were achieved. However, cariporide was absent in the myocardium in all but one specimen obtained before end of cardioplegic arrest, whereas it was again detected at the end of the study (2.5±0.3 ng/mg).

Conclusions: Our data suggest that cariporide is washed out from the myocardium by repeated intracoronary infusion of crystalloid cardioplegia and is not present in the myocardium immediately before reperfusion. Accordingly, no effect on LV-function or myocardial damage was observed.