Comparison of standard (non-oxygenated) vs. oxygenated St. Thomas' Hospital cardioplegic solution No. 2 (Plegisol)

Recent studies have suggested that oxygenation of crystalloidcardioplegic solutions improves myocardial preservation. To assess whetheroxygenation of St. Thomas' Hospital cardioplegic solution No. 2 (Plegisol)improves its clinical efficacy, 50 patients were randomly assigned into 2groups: (1) those receiving Plegisol and (2) those receiving O2-Plegisol(PO2 greater than 500 mmHg at 4 degrees C). Efficacy was assessed by (a)clinical and haemodynamic parameters, (b) quantitative birefringencechanges in response to ATP and calcium as a measurement of myocardialpreservation in left and right ventricular biopsies, (c) creatine kinase(MB isoenzyme) release for up to 4 days postoperatively, (d)electrocardiographic (ECG) monitoring for up to 7 days postoperatively.There were no differences in mean age, ejection fraction, aorticcross-clamp duration, or bypass duration between the 2 groups of patients.In the Plegisol group, 2 patients (8%) died and 4 patients (16%) requiredinotropic support, whereas in the O2-Plegisol group there were no deathsand only 2 patients (8%) required inotropic support. These differences,however, were not statistically significant. Birefringence assessmentdemonstrated an improved myocardial response to ATP and calcium(predominantly in the left ventricular epimyocardium and in the rightventricular biopsies) at the end of ischaemia and after reperfusion inpatients given O2-Plegisol. Deterioration in cellular assessment ofmyocardial contractility (measured by a reduction in birefringence ofgreater than 0.4 nm) was reduced from 20% in Plegisol patients to 12.5% inO2-Plegisol patients. CK-MB values showed no difference at any samplingtime between the 2 groups of patients; a mean peak CK-MB of 35 IU/loccurred 2 h postoperatively.