Does simultaneous antegrade and retrograde cardioplegia improve functional recovery and myocardial homeostasis?

Occluding the junction of the middle cardiac vein in retrograde cardioplegia: a new retrograde cannula for optimizing retrograde cardioplegic delivery

Retrograde cardioplegia often fails to provide adequate perfusion of the right ventricle and the posterior wall of the left ventricle because of the shunt through the thebesian vein. However, much of the retrograde cardioplegic solution may leak into the right atrium after veno-venous anastomoses at the apex of the heart, especially when a retrograde balloon cannula is inserted too deeply in the great cardiac vein, although this is not widely recognized. We designed a new retrograde cardioplegic cannula with three self-inflating balloons, which reduced the shunt flow by occluding the junction of the middle cardiac vein and improving in cardioplegic delivery. We describe the myocardial dye distribution achieved by using this new cannula in pig hearts and report the results of its clinical application.

Continuous cold blood cardioplegia improves myocardial protection: a prospective randomized study

BACKGROUND

To assess the influence on myocardial protection of the rate of infusion (continuous vs intermittent) of cold blood cardioplegia administered retrogradely during prolonged aortic cross-clamping. The end-points were ventricular performance and biochemical markers of ischemia.

METHODS

Seventy patients undergoing myocardial revascularization for three-vessel disease were prospectively randomized to receive intermittent or continuous retrograde cold blood cardioplegia. Hemodynamic measurements were obtained using a rapid-response thermodilution catheter and included right ventricular ejection fraction, cardiac output, left and right ventricular stroke work index, and systemic and pulmonary vascular resistance. Blood samples were obtained from the coronary sinus before cross-clamp application and immediately after cross-clamp removal for determinations of lactate and hypoxanthine.

RESULTS

The left ventricular stroke work index trend was significantly superior (p = 0.038) by repeated-measures analysis in continuous cardioplegia. Other hemodynamic measurements revealed a similar trend. The need for postoperative inotropic drugs support was reduced in continuous cardioplegia. The release of lactate in the coronary sinus after unclamping was 2.30 +/- 0.12 mmol/L after intermittent cardioplegia and 1.97 +/- 0.09 mmol/L after continuous cardioplegia (p = 0.036). The release of hypoxanthine was 20.47 +/- 2.74 micromol/L in intermittent cardioplegia and 11.77 +/- 0.69 micromol/L in continuous cardioplegia (p = 0.002).

CONCLUSIONS

Continuous cold blood cardioplegia results in improved ventricular performance and reduced myocardial ischemia in comparison with intermittent administration.