Table 6.

Major studies using cardiac magnetic resonance to assess Type 5 myocardial infarction following coronary artery bypass graft surgery

Study	Number of patients	Type of surgery	Cardiac biomarkers	Incidence of MI (LGE on CMR)	Major findings
Steuer et al.17	23	CABG	CKMB/cTnT/cTnI Days 1, 2, and 4 after surgery	18/23 (78%) CMR 4–9 days	First study to use CMR to visualise PMI following CABG surgery. Median LGE mass in patients with PMI was 4.4 g (2.5% of LV). Mixed pattern of LGE with transmural, subendocardial and patchy features. Moderate correlation between elevations in CK-MB, cTnT, cTnI at day 1 and LGE mass. Four patients with transmural LGE all had CK-MB ≥5× URL No pre-op CMR scan performed which may explain the higher than expected incidence of LGE on post-surgery CMR.
Selvanayagam et al.15	53	CABG (on pump vs. off pump)	cTnI At 1, 6, 12, 24, 48 and 120 h after surgery	9/26 (35%) (on pump) CMR day 6 (range 4–17) 12/27 (44%) (off pump) CMR day 6 (range 4–17)	New median LGE mass in patients with PMI was 6.3±3.6 g on pump and 6.4 ± 4.0 g off pump Moderate correlation between elevations in AUC cTnI and LGE mass (r2 = 0.4). Only 4 of the 21 patients with LGE on CMR had new Q waves on ECG. Pre-op CMR revealed 47–53% patients had LGE prior to surgery (mean LGE mass 19 g).
Pegg et al.16,74	40	CABG (ONBEAT—on pump beating heart vs. ONSTOP—on pump cardioplegia)	cTnI and CK-MB At 1, 6, 12, 24, 48, and 120 h after surgery	6/17 (35%) (ONBEAT) CMR day 6 or 7 (range 6–11.5) 12/23 (52%) (ONSTOP) CMR day 6 or 7 (range 6–11.5)	New median LGE mass in patients with PMI was 8.2 ± 5.2 g ONSTOP and 9.8 ± 9.0 g ONBEAT Good correlation between AUC and 24 h cTnI, CK-MB and new LGE mass. Mixed pattern of LGE with transmural and subendocardial features. Pre-op CMR revealed 100% patients had LGE prior to surgery. cTnI value >6.6 µg/L (165× URL) at 24 h detection of Type 5 MI on LGE-CMR. cTnI better than CK-MB for quantifying myocardial injury
Lim et al.61	28	CABG	cTnI and CK-MB At 1, 6, 12, 24 h after surgery	9/28 (32%) CMR day 7 (4–10)	cTnI > 83.3× URL at 1 h and peak cTnI/CK-MB at 24 h correlated with new LGEcTnI better than CK-MB in predicting new LGE at both 1 and 24 hNone of the 9 patients with new LGE had Q waves on ECGPre-op CMR performed
van Gaal et al.75	32	CABG	cTnI and CK-MB At 1, 6, 12, 24 h after surgery	9/32 (28%) CMR day 7 (4–10) and 6 months.	New mean LGE mass 8.7 g on acute scan—no significant change in LGE mass at 6 months There was a strong correlation between the absolute peak cTnI 24 h post-procedure and LGE. Pre-op CMR performed
Alam et al.76	69	CABG (Elafin vs. placebo)	cTnI At 2, 6, 24 and 48 h after surgery	25% CMR day 5	No difference in AUC cTnI or new LGE mass with Elafin (potent endogenous neutrophil elastase inhibitor—an anti-inflammatory agent) No data on LGE mass given Pre-op CMR performed
Hueb et al.14	136	CABG (on pump vs. off pump)	cTnI and CK-MB At 6, 12, 24, 36, and 48 h after surgery	13/69 (19%) (on pump) CMR day 6 14/67 (21%) (off pump) on CMR day 6	No data on LGE mass given CK-MB better than cTnI in predicting patients with LGE following CABG surgery The best cut-off for cTnI in predicting Type 5 MI (new LGE on CMR) for on-pump CABG was 162.5× URL and for off-pump CABG was 112.5× URL. The best cut-off for CK-MB in predicting LGE (Type 5 MI) for on-pump CABG was 8.5× URL and for off-pump CABG was 5.1× URL. New Q waves in ECG present in only 7/136 (5%) patients Pre-op CMR performed

AUC, area under the curve; CABG coronary artery bypass grafting; CMR, cardiac MRI; CK-MB, creatine kinase-MB fraction; d, day; ECG, electrocardiogram; ECHO, echocardiocardiogram; HR, hazards ratio; h, hour; LGE, late gadolinium enhancement; LV, left ventricle; MACE, major adverse cardiac events; MI, myocardial infarction; mth, month; ng, nanogram; ONBEAT, on-pump beating heart; CABG ONSTOP, on-pump CABG; OR, odds ratio; post-op, post-operative; PMI, perioperative myocardial injury; RR, relative risk; TEE, transoesophageal echocardiogram; cTnI, Troponin I; cTnT, Troponin T; UA, unstable angina; URL, upper reference limit; yr, year.