A haemodynamic study during OPCAB surgery using a new multi-suction cardiac positioner.

ABSTRACT

BACKGROUND: Displacement of the heart is necessary to expose the target vessel for distal anastomosis to achieve successful multivessel off-pump coronary artery bypass (OPCAB) grafting. In addition to complete revascularisation of the heart, a main challenge during the operation is to maintain haemodynamic stability during this procedure. A new heart positioner (Tentacles) was tested. METHODS: In a prospective clinical study we used the Tentacles device in 50 patients scheduled for multivessel OPCAB procedures and investigated the haemodynamic effects during displacement of the heart and while performing the anastomoses to the anterior, lateral and posterior wall. The following haemodynamic parameters were investigated mean arterial blood pressure (MAP), cardiac index (CI) and stroke volume index (SVI). The incidence of myocardial ischaemia was monitored by transoesophageal echocardiography (TEE) and by ST-segment analysis in the electrocardiogram (ECG). RESULT: The Tentacles device permitted rapid, secure and excellent exposure of the lateral and posterior wall of the heart. During exposure of the anterior wall there was a small decrease in MAP (77 ± 10 vs.71 ± 9 mmHg, P = 0.02) in combination with an increase in the CI (3.0 ± 0.7 l vs. 3.1 ± 0.8 l/min/m2, P = 0.03). When the lateral and posterior walls of the heart were exposed, the SVI decreased significantly (36 ± 11 and 38 ± 8 mL/m2, P < 0.01 and P = 0.04, respectively) compared to baseline (44 ± 11 mL/m2) while CI and MAP remained stable. The amount of norepinephrine administered during displacement of the heart was significantly higher in all three positions (0.05 ± 0.05, 0.06 ± 0.05 and 0.04 ± 0.03 µg/kg/min, P < 0.01) compared to the physiological position (0.02 ± 0.02 µg/kg/min). Sinus rhythm was maintained throughout the operation. Neither significant changes of the ST-segment in the ECG nor incidences of wall motion abnormality in TEE were observed. Six hours postoperatively the troponin I concentration was 11.7 ± 4.3 ng/mL. CONCLUSION: The Tentacles device provided excellent access in multivessel OPCAB surgery. Haemodynamic stability was maintained in all patients; however additional catecholamine support was used when the heart was displaced. This was the case when carrying out an anastomosis on the anterior, lateral, or posterior wall.