Does intermittent cross-clamp fibrillation provide ... - Semantic Scholar

ARTICLE IN PRESS doi:10.1510/icvts.2009.209437

Interactive CardioVascular and Thoracic Surgery 9 (2009) 872–878 www.icvts.org

Best evidence topic - Coronary

Does intermittent cross-clamp fibrillation provide equivalent myocardial protection compared to cardioplegia in patients undergoing bypass graft revascularisation? Marco Scarci*, Hazem B. Fallouh, Christopher P. Young, David J. Chambers Cardiothoracic Surgery Unit, Guy’s and St Thomas’ NHS Foundation Trust, 6th Floor, East Wing, St Thomas Hospital, London, SE1 7EH, UK Received 28 April 2009; received in revised form 22 July 2009; accepted 24 July 2009

Summary A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: does intermittent cross-clamp fibrillation provide equivalent myocardial protection compared to cardioplegia in patients undergoing bypass graft revascularisation? Altogether, 58 papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We identified 13 studies, of which eight were randomised prospective trials. None of these studies found increased mortality, seven analyzed serum cardiac enzymes and showed that intermittent ischemic arrest provides equal or better protection compared to cardioplegic techniques. Two studies found an increased usage of inotropes and intra aortic balloon pump (IABP) in the intermittent ischemic arrest group. We conclude that intermittent cross-clamp fibrillation is a versatile and cost-effective method of myocardial protection, with the immediate postoperative outcome comparable to cardioplegic arrest in first-time coronary artery bypass graft (CABG). The ischaemic duration associated with intermittent cross-clamp fibrillation is invariably shorter than that associated with cardioplegic arrest, and this may be one explanation for the comparable outcomes. There may also be an element of preconditioning protection during the intermittent cross-clamp fibrillation method, as has been shown experimentally. During elective CABG in patients with no clinical evidence of aortic or cerebro-vascular disease, the incidence of peri-operative microemboli (ME) and postoperative neuropsychological disturbances are shown to be comparable with both techniques of myocardial preservation. 䊚 2009 Published by European Association for Cardio-Thoracic Surgery. All rights reserved. Keywords: Aged; Aortaysurgery; Coronary aneurysmysurgery; Coronary artery bypass methods; Heart arrest; Induced methods hypothermia; Humans

1. Introduction A best evidence topic was constructed according to a structured protocol. This is fully described in the ICVTS w1x. 2. Three-part question In wpatients undergoing on-pump coronary artery bypass surgeryx is wintermittent cross-clamp fibrillationx equivalent to wcardioplegic techniquesx in terms of wmorbidity and mortalityx?

compared to cardioplegic arrest. You are not convinced and resolve to check the literature yourself. 4. Search strategy Medline 1950 to present using OVID interface: wexp Ventricular FibrillationyOR fibrillation.mp.x AND wintermittent$.mpx AND wexp Thoracic surgeryyOR exp Coronary Artery BypassyOR CABG.mp. OR coronary artery bypass. mpx. In addition, the reference lists of all relevant papers were searched.

3. Clinical scenario

5. Search outcome

You are at a national conference hearing an eminent speaker reporting his results for coronary artery bypass graft (CABG) using intermittent cross-clamp fibrillation. He continues to say that, although the technique is becoming progressively less popular, it still has the same results

Using the reported search strategy, 58 papers were found and 13 papers were identified and selected as providing the best evidence to answer the question. These are presented in Table 1. 6. Results

*Corresponding author. Tel.: q447515542899 (mobile)yq4471887188 (hospital). E-mail address: [email protected] (M. Scarci). 䊚 2009 Published by European Association for Cardio-Thoracic Surgery

Musumeci et al. w2x reported a prospective randomised clinical trial, which enrolled 91 patients undergoing elec-

ARTICLE IN PRESS M. Scarci et al. / Interactive CardioVascular and Thoracic Surgery 9 (2009) 872–878

873

Table 1 Best evidence papers Author, date and country, Study type (level of evidence)

Patient group

Outcomes

Key results

Comments

Musumeci et al., (1998), Eur J Cardiothorac Surg, UK, w2x

91 CABG patients prospectively randomised to 2 groups: IIA (intermittent ischaemic arrest with fibrillation; ns43) vs. SCT wsingle clamp technique with intermittent antegrade cold (4–8 8C) oxygenated blood cardioplegia; ns48x

Serum CK-MB, troponin T (TnT), troponin I (TnI)

Median peak CK-MB: 26 mgyl IIA vs. 18 mgyl SCT (P-0.02) Median peak TnT: 0.8 mgyl IIA vs. 1.08 mgyl SCT (P-0.03) Median peak TnI: 0.64 mgyl IIA vs. SCT 0.87 mgyl (PsNS)

Serum level of S-100

Normal range (-0.2 mgyl) for all patients (except one with a stroke)

During elective CABG in patients with no clinical evidence of aortic or cerebro-vascular disease the incidence of peri-operative ME and postoperative neuropsychological disturbances are comparable with both techniques of myocardial preservation. Biochemical analysis suggests that IIA provides more effective myocardial preservation

Cooling to 34 8C for IIA and 28 8C for SCT

Microemboli (ME) measured by transcranial Doppler of right middle cerebral artery

Median MEs per patient similar: IIAs34, SCTs34.5, (PsNS)

Neuropsychological disturbance measured by Luria Nebraska Neuropsychological Battery (LNNB)

LNNB score worse at 7 days postoperatively, but improved at 6 months postoperatively. PsNS between groups

Serum CK-MB, aspartate transaminase (AST)

Mean CK-MB values similar for 24 h after aortic cross-clamp release, at 48 h CK-MB lower (P-0.05) in IIA. Similar AST values between groups

ECG changes

Peri-operative MI: 1 patient in each group Persistent ST changes: IIA, 4 patients: SCT, 7 patients. PsNS

Ischaemic duration (min): IIA 31"9 SCT 61"16, P-0.001

LV Biopsies

Evidence of post-ischaemia deterioration: IIA, 1 patient; SCT, 2 patients. PsNS

20 CABG patients prospectively randomised to 2 groups: IIA (intermittent ischaemic arrest with fibrillation; ns10) vs. SCT wcold (4 8C) St Thomas’ Hospital cardioplegia; ns10x

Serial measurement of serum TnT

Peak median serum TnT at 6 h postoperatively wIIA, 1.9 (1.0–3.5) mgyl; SCT, 1.8 (1.0–3.6) mgyl, PsNSx. No difference between groups at any time

This trial shows that intermittent ischaemic arrest provides a similar level of myocardial protection compared to crystalloid cardioplegia

Intramyocardial pH probe measured the level of acidosis in the anterior and posterior myocardium in realtime. The pH at the start and end of each period of cross-clamp recorded

Initial pH was 7.133 (range 6.974–7.239). After first cross-clamp period, pH was 6.381 (range 6.034–6.684), recovering to 6.723"0.324 (but highly inconsistent). Patients split into recoverers (6.990"0.561) compared to non-recoverers (6.455"0.067) (P-0.0005). This was repeated after each cross-clamp release. However, no difference in pH at end of bypass (7.062 vs. 7.038)

Cross-clamp fibrillation does not result in reliable reperfusion of the myocardium between cross-clamp periods

Prospective randomised trial (level 1b)

Ischaemic duration (min): IIA 34.5"16.5 SCT 67.6"16.1, P-0.001

Pepper et al., (1982), Thorax, UK, w3x Prospective randomised trial (level 1b)

50 CABG patients prospectively randomised to 2 groups: IIA (intermittent ischaemic arrest with fibrillation; ns25) vs. SCT wcold (4 8C) St Thomas’ Hospital cardioplegia; ns25x Cooling to 32 8C for IIA and 25 8C for SCT

Taggart et al., (1994), Br Heart J, UK, w4x

Cooling to 34 8C for IIA and 28 8C for SCT Ischaemic duration (min): IIA 32"5 SCT 30"9, PsNS Dunning et al., (2006), J Cardiothorac Surg, UK, w5x

16 CABG patients subjected to cross-clamp fibrillation

Prospective cohort study (level 2b)

37 8C CPB Ischaemic duration (min): IIA 29"7

(Continued on next page)

Best Evidence Topic


Equal protection of the myocardium was provided in both groups

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M. Scarci et al. / Interactive CardioVascular and Thoracic Surgery 9 (2009) 872–878

Table 1 (Continued) Author, date and country, Study type (level of evidence)

Patient group

Outcomes

Key results

Comments

Alex et al., (2003), Interact CardioVasc Thorac Surg, UK, w6x

1454 CABG patients over 5-year period divided into 2 groups: A, antegrade – retrograde cold blood St Thomas’ cardioplegia (ns671), B, intermittent cross-clamp fibrillation (ns783)

No. of grafts, bypass duration (min)

A: 2.9"0.8, B: 2.7"0.7 (P-0.001) A: 64.4"20.0, B: 56.2"17.4 (P-0.001)

Cross-clamp duration (min)

A: 39.1"12.4, B: 25.9"8.6 (P-0.001)

Intermittent cross-clamp fibrillation is a versatile and cost-effective method of myocardial protection, with the immediate postoperative outcome comparable to antegrade – retrograde cold St Thomas blood cardioplegia in elective first-time CABG

IABP usage rate (%)

0.9 vs. 2, Ps0.08

Serial measurement (upto 72 h) of: lipid peroxidation:

Peak at 1 h, no differences at all time points (PsNS)

Plasma antioxidant status:

Similar initial depression and subsequent recovery at all time points (PsNS)

Serum TnT

No differences between groups at all time points (PsNS)

Mortality

Elective (0.57%), urgent (3.09%), emergency (5.55%)

Postoperative hospital stay

Elective (7.11"5.47 days), urgent (7.59"5.07 days), emergency (7.40"4.01 days)

Parsonnet score

Elective (5.23"5.1), urgent (6.73"6.22), emergency (11.24"11)

Ischaemic duration

Elective (27"10 min), urgent (28"17 min), emergency (22"9 min)

Mortality

IIA (2.5%), SCT (2.1%), Ps0.55

IABP usage rate

IIA (2.4%), SCT (1%), Ps0.04

Mortality

IIA (0.4%), SCT (0%), PsNS

Retrospective cohort study (level 3b)

Cohen et al., (1997), Eur J Cardiothorac Surg, UK, w7x Prospective randomised trial (level 1b)

24 consecutive CABG patients (ejection fraction )30%) prospectively randomised to 2 groups: IIA (intermittent ischaemic arrest with fibrillation; ns13) vs. SCT wcold (4 8C) St Thomas’ Hospital cardioplegia; ns11x

Equivalent myocardial protection between IIA and SCT in patients undergoing elective CABG in terms of free radical activity and antioxidant status

Cooling to 32 8C for IIA and 29 8C for SCT Ischaemic duration (min): IIA 40"3 SCT 55"5, P-0.02 Raco et al., (2002), Ann Thorac Surg, UK, w8x Prospective cohort study (level 3b)

800 consecutive CABG patients (May 1996–July 2000) using IIA (intermittent ischaemic arrest with fibrillation) – elective (556), urgent (220) and emergency (54) Cooling to 32 8C

Liu et al., (1998), Ann Thorac Surg, UK, w9x Retrospective cohort study (level 3b)

1923 CABG patients (January 1992–May 1997) divided into 2 groups: IIA (intermittent ischaemic arrest with fibrillation; ns1345) vs. SCT wcold (4 8C) St Thomas’ Hospital blood cardioplegia; ns578x

Intermittent aortic cross-clamping is a safe technique both in elective and non-elective patients The mortality and morbidity in the three subgroups analysed reflects patients’ distribution against Parsonnet score

There was no difference in outcome detected between the two techniques

Cooling to 32 8C for IIA and 28 8C for SCT Ischaemic duration (min): IIA 31"11 SCT 47"15, P-0.001 Alhan et al., (1996), Ann Thorac Surg, Turkey, w10x Retrospective cohort study (level 3b)

399 consecutive low-risk CABG patients divided into 2 groups: IIA (intermittent ischaemic arrest with fibrillation; ns271) vs. SCT wcold (4 8C) St Thomas’ Hospital cardioplegia; ns128x

Both intermittent aortic crossclamping and cold crystalloid cardioplegia techniques may be used safely in low-risk patients undergoing first-time CABG

Cooling to 32 8C for IIA and SCT



875


Patient group

Outcomes

Key results

40 consecutive low-risk CABG patients were randomised into 2 groups: IIA (intermittent ischaemic arrest with fibrillation; ns20) vs. SCT wcold (4 8C) St Thomas’ Hospital cardioplegia; ns20x

Serial blood samples taken simultaneously from aorta and coronary sinus before CPB and 5, 10, 15, and 20 min after CPB for myocardial lactate extraction

Myocardial lactate release similar between groups at all time points (PsNS)

Cooling to 32 8C for IIA and SCT

CK-MB

Mean peak: IIA (30.1"12.5 IU) SCT (28.3"11.2 IU), PsNS

Ischaemic duration (min): IIA 36.1"12 SCT 46.9"18, Ps0.007

Myocardial biopsies

No difference in both groups

60 consecutive CABG patients were randomised to 2 groups: IIA (intermittent ischaemic arrest with fibrillation; ns30) vs. SCT wBuckberg blood cardioplegia (and cardioplegic reperfusion enriched with glutamate and aspartate); ns30x

Mortality

2 deaths, one in each group (3.3%)

CPB duration (min)

IIA, 85"23 SCT, 100"28 (P-0.05)

Ischaemic duration (min)

IIA, 44.3"14.9 SCT, 62.8"24.5 (P-0.05)

Cardiac index

Comparable increases from preoperative period to first postoperative day (PsNS)

CK-MB

Median peak: IIA, 19.5 IUyml: SCT, 26.4 IUyml (P-0.04). Area under activity curve was no different

TnT

Median peak: IIA, 1.6 ngyml: SCT, 2.2 ngyml (PsNS). Area under activity curve was no different

Left ventricular diastolic function, measured with pulsedwave Doppler transesophogeal echocardiography wpeak flow velocities during early filling and atrial contraction (EyA ratio) and by systolic diastolic superior pulmonary venous flow ratiox measured before CPB and at 5 min and 60 min post-CPB

EyA ratio reduced in all groups at 5 min, but only recovered to near normal at 60 min in group III

Haemodynamic measurements

Cardiac index was significantly higher in group III (P-0.05)

Comments

Ischaemic duration (min): IIA 32.5"10 SCT 41.4"14, P-0.05 Prospective randomised trial (level 1b)

Gerola et al., (1993), J Thorac Cardiovasc Surg, Brazil, w11x Prospective randomised trial (level 1b)

Cooling to 32 8C for IIA and 27 8C for SCT Anderson et al., (1994), Ann Thorac Surg, UK, w12x Prospective randomised trial (level 1b)

40 consecutive CABG patients were randomised to 2 groups: IIA (intermittent ischaemic arrest with fibrillation; ns20) vs. SCT wcold (4 8C) St Thomas’ Hospital blood cardioplegia; ns20x Cooling to 32 8C for IIA and 28 8C for SCT

In myocardial revascularisation, intermittent aortic cross-clamping and blood cardioplegia with warm reperfusion enriched with aspartate-glutamate solution are methods of similar efficiency

For elective CABG, ventricular fibrillation is as effective a strategy to manage the myocardium as blood cardioplegia and it may even be superior

Best Evidence Topic

Ischaemic duration (min): IIA 27"6 SCT 38"10 Casthely et al., (1997), J Thorac Cardiovasc Surg, USA, w13x Prospective cohort study (level 2b)

60 CABG patients were divided into 3 groups (dependent on operating room): I, anterograde cardioplegia (ns20); II, anterograde and retrograde cardioplegia (ns20); III, intermittent ischaemia arrest with fibrillation (ns20) Cooling to 28 8C in all patients Ischaemic duration (min): I, 52"4; II, 50"3; III, 40"1 (P-0.05)

Diastolic pulmonary venous flow returned to normal at 60 min only in group III

The degree of LV diastolic impairment (during CPB) was less when ventricular fibrillation and intermittent aortic cross-clamping were used, and greater when anterograde and retrograde cardioplegia were used



M. Scarci et al. / Interactive CardioVascular and Thoracic Surgery 9 (2009) 872–878


Patient group

Outcomes

Key results

Comments

Sunderdiek et al., (2000), Eur J Cardiothorac Surg, Germany, w14x

103 CABG patients were randomised to 2 groups: IIA (intermittent ischaemic arrest with fibrillation; ns52) vs. SCT wcold (4 8C) crystalloid BretschneiderHTK cardioplegic solution; ns51x

Mortality

IIA, 4 (7.7%); SCT, 2 (4%): PsNS

CK-MB

Peak: IIA, 18.7"12.4 Uyl; SCT, 13.7"11.1 Uyl. PsNS

TnI

Peak: IIA, 60.5"36.4 ngyml; SCT, 41.2"18.7 ngyml. PsNS

Both cardioprotective methods seem to offer sufficient myocardial protection in normal CABG procedures. Cardioplegic arrest seems to offer more beneficial effects in procedures with prolonged ischaemia


Cooling to 27–30 8C for IIA and 30 8C for SCT Ischaemic duration (min): IIA 37"10 SCT 48"10 (P-0.02)

IIA patients with ischaemic duration )40 min had higher enzyme levels than SCT patients

IABP, intra aortic balloon pump; CPB, cardiopulmonary bypass; MI, myocardial infarction; LV, left ventricle; ECG, electro cardiogram.

tive CABG. Hearts were protected by intermittent global ischaemic arrest with fibrillation or single aortic clamp and multiple cold blood cardioplegia infusions. Measurements of peak serum levels of troponin I (TnI), troponin T (TnT) and creatine kinase (CK-MB) showed higher levels in the single clamp technique, but no difference in function measured by echocardiography immediately postoperatively or at six months. In addition, the intra-operative levels of cerebral microemboli (ME) were comparable, as was the incidence of neuropsychological disturbances, assessed by the Luria Nebraska Neuropsychological Battery (LNNB) tests for motor, visual, reading, memory and intellectual processes at one day preoperatively and one week and six months postoperatively. Pepper et al. w3x performed a prospective randomised trial, which enrolled 50 patients to either cold crystalloid cardioplegia or intermittent global ischaemic arrest with fibrillation. Mean serum levels of CK-MB and aspartate transaminase (AST) were similar throughout 24 h postoperatively. Cytochemical analysis of left ventricular fullthickness biopsies (taken before and after cardiopulmonary bypass) showed no differences between groups. Clinical outcome and requirement for inotropic support was also similar, indicating similar levels of myocardial protection. Taggart et al. w4x enrolled 20 patients in a prospective randomized trial comparing multiple brief (10–15 min) periods of ischaemic arrest with fibrillation to cold crystalloid cardioplegia. Serial measurements of TnT showed similar levels throughout 72 h postoperatively in the two groups. In this study, the duration of ischaemia was similar (30 min and 32 min for cardioplegia and intermittent crossclamp fibrillation (ICCF), respectively). Thus, protection was similar with both techniques. Dunning et al. w5x performed a prospective cohort study, in 16 patients undergoing CABG using intermittent crossclamp fibrillation. Intramyocardial pH (in real time) was measured throughout each cross-clamp fibrillation period. They found that, during the reperfusion period when the cross-clamp was open, pH recovery was rapid in some patients but in others it failed to recover completely. After cardiopulmonary bypass (CPB), however, the pH was close to the initial pH in both groups and was not different

between the groups. It was concluded that cross-clamp fibrillation does not result in reliable myocardium perfusion between periods of cross-clamping. Alex et al. w6x reported an experience between two surgeons in consecutive first-time CABG over a 5-year period in a retrospective non-randomised trial of 1454 patients. They examined the immediate postoperative outcome of two groups of patients: 671 underwent CABG using antegrade-retrograde cold St Thomas’ blood cardioplegia (with partial occlusion for proximal anastomoses) and 783 had intermittent cross-clamp fibrillation. Postoperative inotropes, myocardial infarction (MI), arrhythmias, neurological and renal complications, multi-organ failure, sternal rewiring, ventilation, length of stay and mortality were comparable between the two groups; however, the intermittent ischaemic arrest group had a significantly longer intensive therapy unit (ITU) stay. It was concluded that ICCF was a versatile and cost effective method of myocardial protection with comparable immediate (hospital stay) postoperative outcome to blood cardioplegia. Cohen et al. w7x examined a small cohort of 24 consecutive CABG patients within a prospective randomized trial. Patients were randomised to intermittent cross-clamp fibrillation for distal anastomoses (with proximal anastamoses constructed using side-biting clamp during reperfusion), or antegrade cold crystalloid cardioplegia for all distal anastomoses. Measurements of lipid peroxidation, antioxidant status and TnT demonstrated no differences between the two groups, indicating similar protective properties for these techniques. Raco et al. w8x examined 800 patients conducted by a single surgeon who underwent first-time CABG using intermittent cross-clamp fibrillation in a prospective cohort study. Patients were subsequently divided into elective (520), urgent (226) and emergency (54). Subgroup analysis indicated that this technique was safe for all patients with lower morbidity and mortality characteristics in relation to Parsonnet score. Liu et al. w9x reviewed 1923 non-emergency patients who underwent first-time elective or urgent CABG from January 1992 to May 1997, by four consultant surgeons. Antegrade cold blood cardioplegia for distal anastomoses was used in


ESCVS Article Proposal for Bailout Procedure Negative Results Follow-up Paper State-of-the-art Best Evidence Topic Nomenclature Historical Pages Brief Case Report Communication

w1x Dunning J, Prendergast B, Mackway-Jones K. Towards evidence-based medicine in cardiothoracic surgery: best BETS. Interact CardioVasc Thorac Surg 2003;2:405–409. w2x Musumeci F, Feccia M, MacCarthy PA, Ellis GR, Mammana L, Brinn F, Penny WJ. Prospective randomized trial of single clamp technique versus intermittent ischaemic arrest: myocardial and neurological outcome. Eur J Cardiothorac Surg 1998;13:702–709. w3x Pepper JR, Lockey E, Cankovic-Darracott S, Braimbridge MV. Cardioplegia versus intermittent ischaemic arrest in coronary bypass surgery. Thorax 1982;37:887–892. w4x Taggart DP, Bhusari S, Hopper J, Kemp M, Magee P, Wright JE, Walesby R. Intermittent ischaemic arrest and cardioplegia in coronary artery surgery: coming full circle? Br Heart J 1994;72:136–139. w5x Dunning J, Hunter S, Kendall SW, Wallis J, Owens WA. Coronary bypass grafting using crossclamp fibrillation does not result in reliable reperfusion of the myocardium when the crossclamp is intermittently released: a prospective cohort study. J Cardiothorac Surg 2006;1:45. w6x Alex J, Ansari J, Guerrero R, Yogarathnam J, Cale AR, Griffin SC, Cowen ME, Guvendik L. Comparison of the immediate post-operative outcome of two different myocardial protection strategies: antegrade-retrograde cold St Thomas blood cardioplegia versus intermittent cross-clamp fibrillation. Interact CardioVasc Thorac Surg 2003;2:584–588. w7x Cohen AS, Hadjinikolaou L, McColl A, Richmond W, Sapsford RA, Glenville BE. Lipid peroxidation, antioxidant status and troponin-T following cardiopulmonary bypass. A comparison between intermittent crossclamp with fibrillation and crystalloid cardioplegia. Eur J Cardiothorac Surg 1997;12:248–253. w8x Raco L, Mills E, Millner RJ. Isolated myocardial revascularization with intermittent aortic cross-clamping: experience with 800 cases. Ann Thorac Surg 2002;73:1436–1439; discussion 1439–1440. w9x Liu Z, Valencia O, Treasure T, Murday AJ. Cold blood cardioplegia or intermittent cross-clamping in coronary artery bypass grafting? Ann Thorac Surg 1998;66:462–465. w10x Alhan HC, Karabulut H, Tosun R, Karakoc F, Okar I, Demiray E, Tarcan S, Yigiter B. Intermittent aortic cross-clamping and cold crystalloid cardioplegia for low-risk coronary patients. Ann Thorac Surg 1996;61: 834–839. w11x Gerola LR, Oliveira SA, Moreira LF, Dallan LA, Delgado P, da Luz PL,

Institutional Report

References

Protocol

We conclude that intermittent cross-clamp fibrillation is a versatile and cost-effective method of myocardial protection, with the immediate postoperative outcome comparable to cardioplegic arrest in first-time CABG. The ischaemic duration associated with intermittent crossclamp fibrillation is invariably shorter than that associated with cardioplegic arrest, and this may be one explanation for the comparable outcomes. There may also be an element of preconditioning protection during the intermittent cross-clamp fibrillation method, as has been shown experimentally w15x. During elective CABG in patients with no clinical evidence of aortic or cerebro-vascular disease, the incidence of peri-operative ME and postoperative neuropsychological disturbances are shown to be comparable with both techniques of myocardial preservation.

Work in Progress Report

7. Clinical bottom line

New Ideas

crystalloid cardioplegia (Bretschneider-HTK solution) or ICCF. Measurements up to 10 days postoperatively of inotropic support, biochemical enzyme release (CK-MB and TNI) and electrocardiogram (ECG) changes demonstrated no significant differences between the groups. Analysis of patients with ischaemic durations in excess of 40 min suggested that ICCF may be less effective under these circumstances.

Editorial

578 patients. Intermittent aortic cross-clamp fibrillation for distal anastomosis construction with reperfusion and defibrillation for proximal anastomosis construction was used in 1345 patients. There were no differences between the groups in terms of mortality (2.52% in ICCF and 2.07% in blood cardioplegia) or for morbidity parameters (although there was a significant difference in incidence of balloon pump usage of 2.4% compared to 1.0% for ICCF or blood cardioplegia, respectively). It was concluded that either technique of myocardial protection is acceptable; it was suggested, however, that ICCF should only be used if each distal anastomosis is done within a 15-min period. Alhan et al. w10x conducted a retrospective analysis of 399 consecutive low-risk patients undergoing first-time CABG using either ICCF or cold crystalloid cardioplegia for myocardial protection. There were no differences in mortality or morbidity between these groups. Subsequently, a prospective randomised trial in 40 consecutive lowrisk patients was conducted, measuring haemodynamics, enzyme release and ultrastructural changes in left ventricle (LV) biopsies. These measurements also showed no differences between the groups, and it was concluded that either myocardial protection technique was safe in low-risk patients. Gerola et al. w11x conducted a prospective randomised controlled trial in 60 elective CABG patients to compare the efficiency of ICCF and the Buckberg method of cardioplegic protection (involving cold blood cardioplegia for induction and maintenance of arrest, with warm cardioplegia enriched with glutamate and asparate for the initial 5 min of reperfusion). Haemodynamics and enzyme release (CK-MB) showed no differences between these groups, and it was concluded that the two methods had similar myocardial protection efficiency. Anderson et al. w12x randomised 40 patients undergoing elective CABG to intermittent cross-clamp fibrillation or cold blood cardioplegia. Enzyme markers of myocardial injury (CK-MB and TnT) were measured for 48 h postoperatively. Analysis of peak values together with area under the curve of total enzyme release showed no differences between the two groups. It was concluded that either method of myocardial protection was effective in elective patients. Casthely et al. w13x examined the effects of three myocardial protection techniques on diastolic function in 60 patients scheduled for elective CABG. They were divided into three equal groups of either antegrade cold blood cardioplegia, antegrade and retrograde cold blood cardioplegia or intermittent cross-clamp fibrillation. All patients had normal diastolic function preoperatively, assessed by pulsed-wave Doppler transesophageal echocardiography, and ejection fraction was also determined. At 5 min after discontinuation of cardiopulmonary bypass, diastolic function was impaired in all groups but had only returned to normal control values at 60 min post-CPB in the ICCF group. No differences in haemodynamics were detected between groups. It was concluded that ICCF causes less impairment of function (manifest as reduced myocardial stunning) than the cardioplegia techniques. Sunderdiek et al. w14x conducted a prospective randomised trial in 103 consecutive CABG patients using either cold

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w13x

w14x

w15x

M. Scarci et al. / Interactive CardioVascular and Thoracic Surgery 9 (2009) 872–878 Jatene AD. Blood cardioplegia with warm reperfusion versus intermittent aortic crossclamping in myocardial revascularization. Randomized controlled trial. J Thorac Cardiovasc Surg 1993;106:491–496. Anderson JR, Hossein-Nia M, Kallis P, Pye M, Holt DW, Murday AJ, Treasure T. Comparison of two strategies for myocardial management during coronary artery operations. Ann Thorac Surg 1994;58:768–772; discussion 772–773. Casthely PA, Shah C, Mekhjian H, Swistel D, Yoganathan T, Komer C, Miguelino RA, Rosales R. Left ventricular diastolic function after coronary artery bypass grafting: a correlative study with three different myocardial protection techniques. J Thorac Cardiovasc Surg 1997;114: 254–260. Sunderdiek U, Feindt P, Gams E. Aortocoronary bypass grafting: a comparison of HTK cardioplegia vs. intermittent aortic cross-clamping. Eur J Cardiothorac Surg 2000;18:393–399. Fujii M, Chambers DJ. Myocardial protection with intermittent crossclamp fibrillation: does preconditioning play a role? Eur J Cardiothorac Surg 2005;28:821–831.

eComment: Myocardial protection in high risk coronary surgery Authors: Mohamed F. Ibrahim, PSHC, King Fahd Medical City, Riyadh, Saudi Arabia; Amal A. Refaat

doi: 10.1510/icvts.2009.209437A I congratulate the authors for their efforts w1x. Both intermittent crossclamp fibrillation (ICCF) and cold blood cardioplegia are commonly used in coronary artery bypass surgery. I agree with the authors that ICCF is a versatile technique that can be used in patients with no aortic disease when the repeated application and removal of the aortic cross-clamp could lead to more emboli to the brain. We have published a retrospective study on 615 patients with significant left main disease to compare the postoperative clinical outcome of these two techniques w2x. We found no difference between the two techniques in mortality, the use of IABP, the use of inotropes, ventilation duration and the hospital stay. I believe that the real difference between myocardial protection techniques should be evident when tested against high risk patients. References w1x Scarci M, Fallouh HB, Young C, Chambers DJ. Does intermittent crossclamp fibrillation provide equivalent myocardial protection compared to cardioplegia in patients undergoing bypass graft revascularisation? Interact CardioVasc Thorac Surg 2009;9:872–878. w2x Ibrahim MF, Refaat AA, Elghobary T, Ammar A. Comparison of postoperative outcome of two myocardial protection strategies in patients with left main disease. J Egypt Soc Cardiothorac Surg 2007;16:38–42.

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