Cite this article as: Madershahian N, Scherner M, Weber C, Kuhn E, Choi Y-H, Slottosch I et al. Temporary biventricular pacing improves bypass graft flows in coronary artery bypass graft patients with permanent atrial fibrillation. Interact CardioVasc Thorac Surg 2015;21:435–40.
Temporary biventricular pacing improves bypass graft flows in coronary artery bypass graft patients with permanent atrial fibrillation Navid Madershahian*, Maximilian Scherner, Carolyn Weber, Elmar Kuhn, Yeong-Hoon Choi, Ingo Slottosch and Thorsten Wahlers Department of Cardiothoracic Surgery, Cologne University Heart Centre, Cologne, Germany * Corresponding author. Department of Cardiothoracic Surgery, Cologne University Heart Centre, Kerpener Strasse 62, 50937 Cologne, Germany. Tel: +49-221-47832453; fax: +49-221-47832509; e-mail: [email protected] (N. Madershahian). Received 16 December 2014; received in revised form 8 May 2015; accepted 12 May 2015
Abstract OBJECTIVES: We have previously demonstrated the impact of univentricular pacing modalities on bypass graft flow (BGF) in the coronary artery bypass graft (CABG) patient with permanent atrial fibrillation (AF). The aim of the present study was to determine the mechanism of this improved coronary conduit and, in addition, to explore the possible benefits with biventricular pacing in patients with and without severe left ventricular dysfunction. METHODS: In 43 CABG patients [mean age 69.5 ± 1.3 years; ejection fraction (EF) 49 ± 2%] with AF, we analysed coronary vascular resistances (CVRs) and the contemporary changes in the BGF obtained during right ventricular outflow tract (RVOT), right- (RV), left- (LV) and right–left ventricular pacing (biventricular pacing, BiVP) using the ultrasonic transit-time methodology. RESULTS: BiVP resulted in the highest percentage decrease of CVR in the overall study group by 17.5 ± 3.0% (P < 0.001), followed by RVOT pacing with 13.9 ± 3.9%. Accordingly, the highest mean BGF was achieved during BiVP, resulting in a 21.6 ± 2.6% increase when compared with no pacing and 16 ± 3.7% when compared with RV pacing. Analysis of patients according to their preoperative LV function (EF ≥50%, n = 26; EF 100 beats/min) or the presence of a permanent pacing system. Preoperative ECG details were noted, including rhythm, QRS duration and aberrant conduction. Perioperative risk was predicted by EuroSCORE. Left ventricular ejection fraction (LVEF) was measured by ventriculography.
Surgical technique The technique of operation was similar in all patients. Cardiopulmonary bypass was performed with standard equipments and techniques using routine cannulation (right atrial cannulation and ascending aortic cannulation) under systemic normothermia and cardiac arrest achieved using antegrade warm hyperkalaemic blood cardioplegia. Cardioplegia was repeated every 20 min or whenever electrical activity resumed. All distal anastomoses were carried out during a single interval of aortic cross-clamping, and the aortic anastomoses were performed with partial aortic cross-clamping while the heart was kept in the beating, empty state. The site of the proximal anastomosis was chosen in order to achieve an optimal bypass course without kinking or tension.
Transit-time flow measurement is a well-established method for intraoperative quality control during coronary artery bypass grafting [6, 7]. ECG-triggered blood flow measurements were performed using a transit-time flowmeter (CardioMed CM2005, MediStem AS, Oslo, Norway) under stable haemodynamic conditions. The same transit flow measurement set-up was used in all cases. Probes measuring 2, 3 and 4 mm in size were available to avoid distortion or compression of grafts. The flexible perivascular flow probes were placed 2 cm from the proximal anastomosis and chosen to fit perfectly around the grafts using a small amount of sterile gel. Only saphenous vein grafts with a single distal anastomosis were used for measurement. For demonstrative technical reasons, arterial grafts (i.e. left internal mammary artery (LIMA)) were not included in the study. The target vessel differed among patients, but all patient measurements were performed within the same graft, which served as an internal control. Flow measurements included mean flow (ml/min) and the pulsatility index (PI). The PI, expressed as an absolute number, is an index related to the resistance to flow distal to the measurement site in the graft. Clinical studies have shown that a PI of
Temporary biventricular pacing improves bypass graft flows in coronary artery bypass graft patients with permanent atrial fibrillation Navid Madershahian*, Maximilian Scherner, Carolyn Weber, Elmar Kuhn, Yeong-Hoon Choi, Ingo Slottosch and Thorsten Wahlers Department of Cardiothoracic Surgery, Cologne University Heart Centre, Cologne, Germany * Corresponding author. Department of Cardiothoracic Surgery, Cologne University Heart Centre, Kerpener Strasse 62, 50937 Cologne, Germany. Tel: +49-221-47832453; fax: +49-221-47832509; e-mail: [email protected] (N. Madershahian). Received 16 December 2014; received in revised form 8 May 2015; accepted 12 May 2015
Abstract OBJECTIVES: We have previously demonstrated the impact of univentricular pacing modalities on bypass graft flow (BGF) in the coronary artery bypass graft (CABG) patient with permanent atrial fibrillation (AF). The aim of the present study was to determine the mechanism of this improved coronary conduit and, in addition, to explore the possible benefits with biventricular pacing in patients with and without severe left ventricular dysfunction. METHODS: In 43 CABG patients [mean age 69.5 ± 1.3 years; ejection fraction (EF) 49 ± 2%] with AF, we analysed coronary vascular resistances (CVRs) and the contemporary changes in the BGF obtained during right ventricular outflow tract (RVOT), right- (RV), left- (LV) and right–left ventricular pacing (biventricular pacing, BiVP) using the ultrasonic transit-time methodology. RESULTS: BiVP resulted in the highest percentage decrease of CVR in the overall study group by 17.5 ± 3.0% (P < 0.001), followed by RVOT pacing with 13.9 ± 3.9%. Accordingly, the highest mean BGF was achieved during BiVP, resulting in a 21.6 ± 2.6% increase when compared with no pacing and 16 ± 3.7% when compared with RV pacing. Analysis of patients according to their preoperative LV function (EF ≥50%, n = 26; EF 100 beats/min) or the presence of a permanent pacing system. Preoperative ECG details were noted, including rhythm, QRS duration and aberrant conduction. Perioperative risk was predicted by EuroSCORE. Left ventricular ejection fraction (LVEF) was measured by ventriculography.
Surgical technique The technique of operation was similar in all patients. Cardiopulmonary bypass was performed with standard equipments and techniques using routine cannulation (right atrial cannulation and ascending aortic cannulation) under systemic normothermia and cardiac arrest achieved using antegrade warm hyperkalaemic blood cardioplegia. Cardioplegia was repeated every 20 min or whenever electrical activity resumed. All distal anastomoses were carried out during a single interval of aortic cross-clamping, and the aortic anastomoses were performed with partial aortic cross-clamping while the heart was kept in the beating, empty state. The site of the proximal anastomosis was chosen in order to achieve an optimal bypass course without kinking or tension.
Transit-time flow measurement is a well-established method for intraoperative quality control during coronary artery bypass grafting [6, 7]. ECG-triggered blood flow measurements were performed using a transit-time flowmeter (CardioMed CM2005, MediStem AS, Oslo, Norway) under stable haemodynamic conditions. The same transit flow measurement set-up was used in all cases. Probes measuring 2, 3 and 4 mm in size were available to avoid distortion or compression of grafts. The flexible perivascular flow probes were placed 2 cm from the proximal anastomosis and chosen to fit perfectly around the grafts using a small amount of sterile gel. Only saphenous vein grafts with a single distal anastomosis were used for measurement. For demonstrative technical reasons, arterial grafts (i.e. left internal mammary artery (LIMA)) were not included in the study. The target vessel differed among patients, but all patient measurements were performed within the same graft, which served as an internal control. Flow measurements included mean flow (ml/min) and the pulsatility index (PI). The PI, expressed as an absolute number, is an index related to the resistance to flow distal to the measurement site in the graft. Clinical studies have shown that a PI of
