Clin Res Cardiol 96:Suppl 2 (2007)

P330 - Biventricular pacing after CABG in patients with reduced LV function - The BIVAC-Trial
 
F. Eberhardt1, T. Hanke2, M. Heringlake3, M. Massalme4, M. Misfeld2, U. Wiegand5
 
1Medizinische Klinik II, Kardiologie, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck; 2Klinik für Herzchirurgie, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck; 3Klinik für Anästhesiologie, Lübeck; 4Medizinische Klinik II, Kardiologie und Angiologie, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck; 5Medizinische Klinik II, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck;
 
Background: Biventricular pacing (BIV) has been shown to be effective in heart failure patients with severely reduced left ventricular (LV) function and QRS width >120ms. Pressure volume loop analysis has shown acute perioperative hemodynamic benefits of BIV pacing and AAI pacing compared to standard DDD-right ventricular (RV) pacing immediately after weaning from cardiopulmonary bypass in coronary artery bypass grafting (CABG) patients with ejection fraction (EF) <35% and normal QRS-width. However, if prolonged postoperative BIV or AAI pacing translates into clinical benefits in this subset of patients is still unknown.
Hypothesis: BIV pacing is superior to DDD-RV and AAI-pacing (AAI) in CABG pts with EF <40%.
Methods: 92 pts (mean age 67±9y, mean EF 35 ± 4%) were randomised to either BIV, RV or AAI pacing at 90/min for 96h postoperatively. Duration of intensive care unit (ICU) stay, renal dysfunction, incidence of postoperative atrial fibrillation (AF) and ventricular tachycardia (VT), inotropic support, NT-pro-BNP level pre-op and 1h, 24h and 96h post-op were evaluated. A composite endpoint of mortality, stroke, intraaortic-balloon-pump use, myocardial infarction, revascularization and rethoracotomy was defined. Cardiac index (CI), mean pulmonary artery pressure (PAP), mean arterial pressure (MAP) and mixed venous saturation (MVO2) were determined every 4h.
Results: Hemodynamic results are shown in Tab 1 and Fig 1. CI, MAP, PAP, MVO2 and cumulative inotropes did not differ significantly between groups for all time points. Neither raw NT-pro-BNP at all time points nor differential values to pre-op values differed significantly between groups. Mean ICU stay did not differ significantly for all pacing modes. The cumulative clinical endpoint was: AAI: 4, RV: 5; BIV: 5 (not significant (n.s.)). Incidence of postoperative AF was 40% for AAI, 29% for RV and 37% for BIV (n.s.). Cumulative incidence of VT was 11% (n.s.). Glomerular filtration rate (AAI: 83 ± 37; RV: 77 ± 25; BIV 79 ± 35 ml/min) and patients with cumulative RIFLE-Score ≥ 1 (AAI: 17%, RV: 16%; BIV: 26%) did not differ significantly.
Conclusion: BIV is safe and feasible in CABG patients with severly reduced EF. The short-term hemodynamic benefits of BIV do not translate into improved postoperative hemodynamics or clinical outcomes compared to RV and AAI. Thus, routine use of BIV pacing cannot be recommended in this setting. If there is a role for BIV pacing in carefully selected subgroups after CABG needs futher investigation.
 
  AAI DDD BIV
Mean CI [ml/min/m2] 3,20 ± 8,30 3,02 ± 0,88 3,30 ± 0,90
Mean MVO2 [%] 67,5 ± 5,3 70,0 ± 5,4 69,3 ± 5,5
Mean MAP [mmHg] 79,8 ± 10,8 76,1 ± 11,4 77,0 ± 11,0
Mean PAP [mmHg] 28,3 ± 7,5 28,2 ± 6,1 29,0 ± 7,7
NTpro-BNP pre-OP [pg/ml] 2485 ± 3188 3492 ± 4536 3204 ± 3935
Post-OP NTpro-BNP [pg/ml] 5027 ± 5162 8295 ± 8728 7717 ± 8653
Noradrenaline mg/d 0,4 ± 0,8 0,9 ± 2,5 1,7 ± 3,5
Dobutamine mg/d 110 ± 167 129 ± 167 149 ± 230
Milrinone mg/d 6,6 ± 8,9 7,6 ± 10,8 15,7 ± 17
Table 1: Hemodynamic parameters vs pacing mode.


Fig.1: Mixed venous saturation and Cardiac output vs pacing mode.
 


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