BACKGROUND: To analyze the hemodynamic behavior of the heart in revascularization of the myocardium without use of extracorporeal circulation. MATERIAL AND METHODS: From August 1991 to June 1999, 616 patients suffering from angina of the chest underwent revascularization of the myocardium without use of extracorporeal circulation. In 18 patients the intraoperative hemodynamic parameters were studied. RESULTS: Heart rate remained high at all times during positioning of the heart (p=0.0007). Cardiac output throughout the procedure presented a very slight variation at different moments of positioning of the heart and exposure of the coronary arteries. However, once the heart was in its final normal position a major increase in output was noted (p=0.010). Mean blood pressure was found to be decreased throughout the procedure for exposing the coronary arteries (p=0.022). Arterial pulmonary pressure proved to be reduced at all times during mobilization, but without statistical significance. Pulmonary capillary pressure showed considerable, but statistically insignificant variation during exposure of the arteries. Central venous pressure behaved in a more varied fashion during exposure of the arteries, but again without statistical significance. Systemic vascular resistance proved to be diminished throughout the procedure (p=0.0001). Pulmonary vascular resistance remained reduced at all times during the procedure (p=0.002). Stroke volume was unchanged during anastomosis of the anterior interventricular artery and statistically significant differences were observed only in the right coronary (p=0.002) and right circumflex (p=0.0006) artery and its branches. The cardiac index was shown to be diminished throughout the procedure (p=0.0011). CONCLUSIONS: A) The present technique allows for maximum mobilization of the heart without inducing hemodynamic instability. B) The improvement of a number of hemodynamic parameters at the end of the procedure may be accounted for by: (1) the response to the myocardial revascularization; (2) the release of catecholamines following manipulation of the heart in the different positions and (3) the release of vasoactive mediators following prolonged traction of the pericardium.
Myocardial revascularization; Heart; Extracorporeal circulation; Hemodynamics; Intraoperative period
