Is it worth placing ventricular pacing wires in all patients postcoronary artery bypass grafting?

Transcription

1 Interactive CardioVascular and Thoracic Surgery 15 (2012) doi: /icvts/ivs125 Advance Access publication 22 May ADULT CARDIAC Is it worth placing ventricular pacing wires in all patients postcoronary artery bypass grafting? Maziar Khorsandi*, Ishaq Muhammad, Kasra Shaikhrezai and Renzo Pessotto Department of Cardiothoracic Surgery, Royal Infirmary of Edinburgh, Edinburgh, UK * Corresponding author. Department of Cardio-Thoracic Surgery, Royal Infirmary of Edinburgh, 51 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SA. Tel: ; Fax: ; m.khorsandi@sms.ed.ac.uk (M. Khorsandi). Received 24 December 2011; received in revised form 28 February 2012; accepted 6 March 2012 Abstract A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether ventricular pacing wires should be placed routinely in all patients undergoing coronary artery bypass grafting () regardless of immediate post-cardiopulmonary bypass (CPB) rhythm status. Using the reported search, 142 papers were found, from which 10 papers represented the best evidence on the subject. The author, date and of 10 publications, study type, patient group studied, relevant outcomes and results are tabulated. Complete atrio-ventricular (AV) block is the main reason for inserting ventricular pacing wires upon conclusion of. Eight studies found complete AV block to be a rare entity post-. AV block in in our review ranged from 0.3 to 24%. The calculated average rate of AV block in all studies was 2.4%. The number needed to treat with ventricular wires to support a patient who develops AV block is 42. One randomized controlled trial found 3% risk of complete AV block post-. Another cohort of 222 patients revealed a rate of 1.8% for complete AV block. For one cohort of 770 patients, post- the rate of complete AV block was found to be 0.3%. In one cohort of 25 patients, there was a rate of 4% for complete AV block post-. Another study of 564 patients revealed a rate of 0.7% for complete AV block. A study of 4999 patients post- reported a rate of 1.2% for complete AV block. In one cohort of 93 patients, there was a 4% risk of complete AV block. Another cohort of 62 patients showed a rate of 1.6% for complete AV block. Only two papers found the rate of complete AV block post- to be as high as 24 and 16%. Both studies were limited by sample size. In conclusion, routine ventricular pacing wire insertion post- is unnecessary given that routine use of ventricular wires can occasionally cause complications such as bleeding and cardiac tamponade and thus is not risk free. We also found that the incidence of complete AV block is probably higher in on-cpb than off-cpb and that AV pacing may be haemodynamically beneficial for some patients postoperatively. Keywords: Cardiac pacing Epicardium Coronary artery bypass grafting Atrio-ventricular block INTRODUCTION A best evidence topic was constructed according to a structured protocol. This protocol is fully described in ICVTS [1]. CLINICAL SCENARIO You are at a morbidity and mortality meeting, and the first case is a patient who had coronary artery bypass grafting () with moderate left ventricular (LV) function. He did very well, but was anticoagulated on day 3 for atrial fibrillation (AF), and his ventricular wires were removed on day 5 with an international normalised ratio (INR) of 1.7. He developed a slow tamponade over the next 4 h and required reoperation to relieve this complication. He went home 3 weeks later. The second case is a patient who had with moderate LV function and a history of AF who did not have any pacing wires placed intraoperatively. He did well and went to the ward but went into complete atrio-ventricular (AV) block on day 3. This was a very urgent situation, requiring external pacing and then urgent transfer to the catheterization laboratory for a temporary pacing wire. Your anaesthetists comment that all the surgeons have a different policy on whether or not to put ventricular wires, and ask whether anyone could come up with a unit policy on the matter. You are given this task. THREE-PART QUESTION In [ patients post-], is [routine placement of ventricular wires] superior to [no ventricular wires] in reducing [ postoperative complications]? The Author Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

2 490 M. Khorsandi et al. / Interactive CardioVascular and Thoracic Surgery Best evidence papers (level of Puskas et al. (2003), Heart Surg Forum, USA [3] RCT (level 2 Baraka et al., (1995), Anesth Analg, Lebanon [4] Asghar, et al. (2009), Ayoub Medical College, Pakistan [7] Flynn, et al. (2005), Eur Cardiothorac Surg, UK [8] Prospective case control study/rct (level patients underwent. 99 on CPB and 98 off CPB. 33 (17%) of these patients developed postoperative bradycardia or any form of conduction abnormality that required epicardial PW insertion Incidence of complete AV block was studied in a group of 86 patients undergoing on-cpb with potassium cardioplegia solution 1047 consecutive patients underwent between 2006 and Of these, 770 underwent on-cpb alone Exclusion criteria included off-cpb, patients who did not receive a pacing wire, with valvular surgery and patients with preoperative pacemaker 25 patients with left ventricular dysfunction underwent pacing of the RV (control), the anterior LV and the posterior LV in a random order with each pacing mode of 10 min post-cpb Necessity of epicardial PW insertion post- The incidence of AV block and conduction defect requiring pacing post on- and off-cpb AV block post on-cpb Risk factors for developing complete AV block post- Necessity of epicardial PW insertion post-. Incidence of AV block requiring ventricular pacing Identifying preoperative risk factors for pacing The effect of pacing on the CI post on-cpb Site-specific pacing and its effect on the CI 6 (3%) patients developed complete AV block prior to chest closure, requiring ventricular epicardial pacing Conduction rhythm disturbances seem to be more common in the on-cpb group; 11% in the on-cpb group vs 6% in the off-cpb group None of the patients in this study required PPM insertion 24 (27%) patients in this study developed complete AV block after release of the aortic cross-clamp post on-cpb The risk factors identified were old age, patients on a combination of β-blockers and calcium channel blockers, preoperative bradycardia, number of vessels grafted and the duration of aortic cross-clamping Of the 770 patients in the study, two (0.3%) patients developed AV block in the immediate postoperative period, requiring ventricular epicardial pacing Age, preoperative arrhythmia, BBB, pacing requirement upon discontinuation of CBP and use of anti-arrhythmics on leaving the operating room are risk factors for pacing requirement post- One of the two patients requiring pacing required a PPM Only one (4%) patient developed complete AV block, requiring ventricular pacing A significant benefit for patients with pre-existing ventricular dysfunction, in having ventricular pacing post-cardiac surgery to improve CI from 2.74 to 3.08 l/min/m 2 (P = 0.019) (1) Limited sample size. (2) No reference made to the effect of pacing on the EF (1) Limited number of patients.(2) Non-randomization (2) No reference to the number of patients in the paced group who required PPM insertion (3) No reference to the effect of pacing on the EF (1) Good sample size; however, only on-cbp patients were included in the study limiting factor of the study (3) It was unclear whether EF was calculated preoperatively or in the postoperative period while the patient was being paced (1) Sample size too small for the conclusion to be objective limiting factor (3) No reference made to whether any of the paced patients required PPM

3 M. Khorsandi et al. / Interactive CardioVascular and Thoracic Surgery 491 (level of Bethea, et al. (2005), Ann Thorac Surg, USA [9] Imren et al. (2008), J Cardiovasc Surg, Turkey [6] Merin et al. (2009), Pacing Clinical Electrophysiol, Israel [10] Retrospective cohort study (level patients undergoing on-cpb were selected, and the incidence of temporary pacing requirement in these patients was assessed 564 patients underwent, 296 on CPB and 268 off CPB. Epicardial pacing wires were inserted for patients developing AV block 4999 patients underwent cardiac surgery between 1993 and Their cohort included patients who had undergone and AVR Epicardial pacing in on-cpb Effect of pacing for AV conduction defect, BBB and bradycardia The rate of postoperative AV block post- The necessity for ventricular epicardial pacing wire insertion for patients undergoing AV block post cardiac surgery Predicting factors for permanent pacemaker 19 (8.6%) patients required some form of pacing post-cpb in the postoperative period. Of these, four (1.8%) patients developed complete AV block, requiring ventricular pacing post isolated The major risk factors for temporary pacing support included: age, diabetes, cardiomegaly, preoperative anti-arrhythmic therapy and the patients initiated on inotropic support on coming off CPB Two (10%) of the patients in the paced group required PPM Only four (0.7%) patients developed AV block intraoperatively, requiring pacing through ventricular epicardial pacing wires inserted at the conclusion of Epicardial pacing wires are overused in. Careful consideration should be made prior to insertion. Insertion should be limited to a few cases One patient required a PPM Of the 4999 patients who had undergone cardiac surgery, 59 (1.2%) developed complete AV block. Of these, 35 (0.7%) were immediate in onset and persistent and 24 (0.5%) were delayed. The rate of pacemaker post- was only 1%, compared with 5.7% post-avr and 1.8% post-mvr Predictors for need for pacemaker requirement were LBBB and AVR 26 (0.5%) patients required PPM for complete AV block. Of these, 22 (0.4%) were still pacemaker dependent at 72 ± 32 month follow-up (1) The duration of follow-up for patients in the study was very variable (7.4 ± 9.9 days) (2) There were too few patients with the named co-morbidities to consider these as independent risk factors for requiring temporary pacing. (3) Non-randomization is the other limiting factor (4) No reference made to the effect of pacing on the EF postoperatively (1) The number of patients in the study is a limiting factor limiting factor here (3) No reference found for post-pacing EF in the paced group (1) Non-randomization. (2) Incomplete ECG data from archives (3) No reference made to the post-pacing EF in the paced patients Baerman et al. (1987), Ann Thorac Surg, USA [11] 93 consecutive patients underwent. The rate of conduction defect was assessed in this group 2 months follow-up The rate of various conduction defects post- Four (4%) patients developed complete AV block in the postoperative period post-. Most conduction defects self-resolved within 2 months of follow-up Three (75%) of the patients with complete AV block were discharged with PPM. At 3 months follow-up complete AV block had resolved in all The limitations in this study include: (1) the number of patients; (2) non-randomization; (3) short duration of follow-up; (4) no reference made to postoperative EF in the paced group of patients

4 492 M. Khorsandi et al. / Interactive CardioVascular and Thoracic Surgery (level of Caspi et al. (1989), Pacing Clinical Electrophysiol, Israel [13] Bhan et al. (1999), Ann Thorac Surg, India [12] Retrospective cohort study (level 3 SEARCH STRATEGY Medline 1966 to December 2011 using the OVID interface: [exp epicardial pacing wire/or epicardial pacing wire.mp] AND [exp bypass surgery/or.mp OR]. Cochrane database of Systematic Reviews, ACP Journal Club and the Database of Reviews of effects: search performed using keyword epicardial pacing wire. SEARCH OUTCOME One hundred and forty-two papers were found, from which 10 represented the best evidence papers. These papers are outlined in Table 1. RESULTS This study evaluated the rate of complete AV block in 348 consecutive patients who had undergone on-cpb, with cold potassium cardioplegia solution Follow-up 7 28 months. 62 patients were included in this cohort who had undergone with a radial artery graft between 1996 and 1998 AV block Risk factors for developing complete AV block post- The patency rate of radial artery grafts Rate of complications, including conduction defect and bleeding Epicardial pacing wires have been in regular use in cardiac surgery since One of the main indications for insertion of ventricular epicardial pacing wires is complete AV block [2]. Complete AV block commonly develops post- after the release of the aortic cross-clamp and leads to haemodynamic compromise, requiring pacing by means of ventricular epicardial pacing wires to maintain haemodynamic stability [3, 4]. However, placement of ventricular epicardial pacing wires has been associated with rare but catastrophic complications, such as failure of AV sensing or capture, lacerations to coronary grafts (especially 56 (16%) patients developed complete AV block post- The study identified the presence of multivessel disease and ungraftable right dominant artery as a risk factor for development of complete AV block post- Of the 56 patients with AV block, in 32 the block was transient (lasting <6 h) and in 24 it was persistent Only one (1.6%) patient developed complete AV block, requiring ventricular pacing (1) This study is limited by the number of subjects (2) No reference made to the EF on pacing (1) Number of patients and non-randomization were limitations of this study (2) No reference made to post-pacing EF AV: atrio-ventricular; AVR: aortic valve replacement; : coronary artery bypass grafting; CI: cardiac index; CPB: cardiopulmonary bypass; EF: ejection fraction; INR: international normalised ratio; LBBB: left bundle branch block; LV: left ventricle; MAP: mean arterial pressure; MVR: mitral valve replacement; PPM: permanent pacemaker; PW: pacing wire; RA: right atrium; RV: right ventricle; RCT: randomized controlled trial. venous grafts), the atria or the ventricles and retained wires leading to prolonged hospital stay [5]. Bearing these complications in mind, we have looked at the incidence of complete AV block post- to determine the necessity of routine ventricular pacing wire placement. Imren et al. [6], performed a prospective cohort study of 564 patients, with 296 on cardiopulmonary bypass (CPB) and 268 off CPB, in which four (0.7%) patients developed AV block requiring ventricular pacing. Furthermore, Puskas et al. [3] performed a prospective randomized controlled trial (RCT) of 197 patients undergoing both on- and off-cpb and studied the need for epicardial pacing wires. They reported that of their 197 patients, six (3%) developed AV block requiring ventricular pacing prior to chest closure. Asghar et al. [7], performed a large prospective cohort study of 1047 patients undergoing. Of these, 770 had epicardial pacing wires inserted at the conclusion of surgery, of whom two (0.3%) developed complete AV block in the immediate postoperative period, requiring ventricular pacing. These studies identified that routine placement of ventricular epicardial pacing wires post- is unnecessary. Flynn et al. [8], in a cohort of 25 patients, reported that one (4%) patient developed complete AV block following on-cpb, who required ventricular pacing postoperatively. Bethea et al. [9], in a cohort of 222 patients undergoing isolated, identified 19 (8.6%) requiring pacing, of whom four (1.8%) needed ventricular pacing for complete AV block following on-cpb. Merin et al. [10], in a large cohort of 4999 patients undergoing and AVR, reported postoperative complete AV block in 59 (1.2%) patients. Of these, 35 (0.7%) were immediate and persistent and 24 (0.5%) were delayed.

5 M. Khorsandi et al. / Interactive CardioVascular and Thoracic Surgery 493 They reported that patients had significantly lower risk of developing complete AV block postoperatively compared with the AVR and the MVR groups. Baerman et al. [11], performed a prospective cohort study of 93 patients undergoing and investigated the rate of complete AV block postoperatively. Only four (4%) patients developed complete AV block postoperatively. They concluded that complete AV block is a rare entity and that there is a positive correlation between developing new conduction defects postoperatively, including complete AV block, and the number of coronary arteries bypassed, CPB time and aortic cross-clamp time. This was thought perhaps to be due to the ischaemic injury to the conduction system during cardioplegic arrest. Bhan et al. [12] performed a retrospective cohort study of 62 patients who underwent with a radial artery graft as one of the grafts. Of these patients, only one (1.6%) developed complete AV block requiring ventricular pacing. In contrast, Baraka et al. [4], in a prospective cohort study of 86 patients undergoing on-cpb, reported 24% incidence of complete AV block upon release of the aortic cross-clamp, requiring temporary ventricular pacing post-. Furthermore, Caspi et al. [13] reported, in their cohort of 348 patients undergoing on-cpb, that 56 (16%) patients developed complete AV block requiring ventricular pacing, of whom 32 patients had transient and 24 persistent AV block. They identified multivessel disease and an ungraftable right dominant coronary artery to be a risk factor for developing complete AV block postoperatively. Both these studies were limited by the number of subjects and non-randomization. CLINICAL BOTTOM LINE In conclusion, the rate of complete AV heart block is around 2.4%, and thus the number needed to treat with ventricular wires to support a patient who develops AV block is 42. This needs to be balanced with the risk of complications from the wires, such as tamponade on removal. We also found that the incidence of complete AV block is probably higher in on-cpb than off-cpb and that AV pacing maybe haemodynamically advantageous in some patients postoperatively. Conflict of interest: none declared. REFERENCES [1] Dunning J, Prendergast B, Mackway-Jones K. Towards evidence-based medicine in cardiothoracic surgery: best BETS. Interact CardioVasc Thorac Surg 2003;2: [2] Abu-Omar Y, Guerrieri-Wolf L, Taggart DP. Indications and positioning of temporary pacing wires. Multimedia Man Cardiothorac Surg. doi: /mmcts [3] Puskas JD, Sharoni E, Williams WH, Petersen RN, Duke P, Guyton RA. Is routine use of temporary pericardial pacing wires necessary after either OPCAB or conventional /CPB? Heart Surg Forum2003;6: [4] Baraka AS, Taha SK, Yazbeck VK, Rizkallah PA, Zughbi JI, Aouad MJ et al. Transient atrioventricular block after the release of aortic cross-clamp. Anesthesia Analg 1995;80:54 7. [5] Weisse U, Isgro F, Werling C, Lehmann A, Saggau W. Impact of atriobiventricular pacing to poor left-ventricular function after. Thorac Cardiovasc Surg 2002;50: [6] Imren Y, Benson AA, Oktar GL, Cheema FH, Comas G, Naseem T. Is use of temporary pacing wires following bypass surgery really necessary? J Cardiovasc Surg (Torino) 2008;49: [7] Asghar MI, Khan AA, Iqbal A, Arshad A, Afridi I. Placing epicardial pacing wires in isolated coronary artery bypass graft surgery a procedure routinely done but rarely beneficial. J Ayub Med Coll Abbottabad 2009;21: [8] Flynn MJ, McComb JM, Dark JH. Temporary left ventricular pacing improves haemodynamic performance in patients requiring epicardial pacing post cardiac surgery. Eur J Cardiothorac Surg 2005;28: [9] Bethea BT, Salazar JD, Grega MA, Doty JR, Fitton TP, Alejo DA et al. Determining the utility of temporary pacing wires after coronary artery bypass surgery. Ann Thorac Surg 2005;79: [10] Merin O, Ilan M, Oren A, Fink D, Deeb M, Bitran D et al. Permanent pacemaker following cardiac surgery: indications for longterm follow-up. Pacing Clin Electrophysiol 2009;32:7 12. [11] Baerman JM, Kirsh MM, De Buitleir M, Hyatt L, Juni JE, Morady F. Natural history and determinants of conduction defects following coronary artery bypass surgery. Ann Thorac Surg 1987;44: [12] Bhan A, Gupta V, Choudhary SK, Sharma R, Singh B, Aggarwal R et al. Radial artery in : could early results be comparable to internal mammary artery graft? Ann Thorac Surg 1999;67: [13] Caspi J, Amar R, Elami A, Safadi T, Merin G. Frequency and significance of complete atrioventricular block after coronary artery bypass grafting. Am J Cardiol 1989;63:526 9.