ABSTRACT 62

HEMODYNAMIC CHANGES DURING DISPLACEMENT OF THE BEATING HEART USING EPICARDIAL STABILIZATION FOR OFF-PUMP CORONARY BYPASS GRAFTING

Naresh Trehan , Manisha Mishra , Rajneesh Malhotra
Escorts Heart Institute and Research Centre, New Delhi-110025, India

Background: Off pump coronary bypass grafting (OPCAB) significantly reduces the invasiveness of cardiac surgery. Stabilization of the coronary target by mechanical devices is essential for accurate anastomosis. However, luxation of the heart causes hemodynamic changes which may compromise the safety of the procedure. We evaluated the hemodynamic alterations during the procedure along with the measures taken to rectify them.

Methods: Prospective study on 500 patients undergoing multivessel OPCAB using Octopus tissue stabilizer between January 2000 through September 2000. All patients were monitored with radial artery and pulmonary artery catheters, along with continuous TEE monitoring with a multiplane transducer. Perioperative requirement of intracoronary shunt, inotropes and IABP were noted. Effect of Trendelenberg position and fluids on hemodynamics was observed. The need for defibrillation and institution of emergency CPB were major end points to determine the inability of the patient to tolerate tilting of the heart.

Results: Mean patient age was 59.3 ± 9.6 yrs. 204 (40%) patients were in the high risk category. The mean number of grafts was 2.7 ± 0.8. Displacement of heart decreased the mean arterial pressure by 18% ± 4% (p<0.01), along with a concomitant increase in CVP of 66% ± 18% (p<0.001). LV stroke volume and cardiac index reduced by 35.7% ± 11% (p<0.01) and 45% ± 13% (p<0.001) respectively. On TEE there was development of new regional wall motion abnormalities in 59.2% and a decrease in global LV functions in 61.2%. Inotropic support was highest during anastomosis on the posterior wall, 78.4% vs 21.9% for anterior wall. IABP required in 55 (11.2%) and 7 patients  put on emergency CPB. Inhospital mortality was 1.2%.

Conclusions: Most patients exhibited  hemodynamic changes easily manageable by fluids and inotropes. LV and RV function assessment by TEE enhances safety of the procedure. The use of octopus II tissue stabilizer proved to be a safe and versatile means to stabilize the heart, especially in the high risk group of patients.