Abnormal release of cardiac biomarkers in the presence of myocardial oedema evaluated by cardiac magnetic resonance after uncomplicated revascularization procedures

AIMS

To analyse the association of myocardial oedema (ME), observed as high T2 signal intensity (HT2) in cardiac magnetic resonance imaging, with the release of cardiac biomarkers, ventricular ejection, and clinical outcomes after revascularization.

METHODS AND RESULTS

Patients with stable coronary artery disease with the indication for revascularization were included. Biomarker levels [troponin I (cTnI) and creatine kinase MB (CK-MB)] and T2-weighted and late gadolinium enhancement (LGE) images were obtained before and after the percutaneous or surgical revascularization procedures. The association of HT2 with the levels of biomarkers, with and without LGE, evolution of left ventricular ejection fraction (LVEF), and 5-year clinical outcomes were assessed. A total of 196 patients were divided into 2 groups: Group 1 (HT2, 40) and Group 2 (no HT2, 156). Both peak cTnI (8.9 and 1.6 ng/mL) and peak CK-MB values (44.7 and 12.1 ng/mL) were significantly higher in Group 1. Based on the presence of new LGE, patients were stratified into Groups A (no HT2/LGE, 149), B (HT2, 9), C (LGE, 7), and D (both HT2/LGE, 31). The peak cTnI and CK-MB values were 1.5 and 12.0, 5.4 and 44.7, 5.0 and 18.3, and 9.8 and 42.8 ng/mL in Groups A, B, C, and D, respectively, and were significantly different. The average LVEF decreased by 4.4% in Group 1 and increased by 2.2% in Group 2 (P = 0.057).

CONCLUSION

ME after revascularization procedures was associated with increased release of cardiac necrosis biomarkers, and a trend towards a difference in LVEF, indicating a role of ME in cardiac injury after interventions.

Myocardial microstructure assessed by T1 mapping after on-pump and off-pump coronary artery bypass grafting

Background

The correlation between the release of cardiac biomarkers after revascularization, in the absence of late gadolinium enhancement (LGE) or myocardial edema, and the development of myocardial tissue damage remains unclear. This study sought to identify whether the release of biomarkers is associated with cardiac damage by assessing myocardial microstructure on T1 mapping after on-pump (ONCAB) and off-pump coronary artery bypass grafting (OPCAB).

Methods

Seventy-six patients with stable multivessel coronary artery disease (CAD) and preserved systolic ventricular function were included. T1 mapping, high-sensitive cardiac troponin I (cTnI), creatine kinase myocardial band (CK-MB) mass, and ventricular dimensions and function were measured before and after procedures.

Results

Of the 76 patients, 44 underwent OPCAB, and 32 ONCAB; 52 were men (68.4%), and the mean age was 63±8.5 years. In both OPCAB and ONCAB the native T1 values were similar before and after surgeries. An increase in extracellular volume (ECV) values after the procedures was observed, due to the decrease in hematocrit levels during the second cardiac resonance. However, the lambda partition coefficient showed no significant difference after the surgeries. The median peak release of cTnI and CK-MB were higher after ONCAB than after OPCAB [3.55 (2.12-4.9) vs. 2.19 (0.69-3.4) ng/mL, P=0.009 and 28.7 (18.2-55.4) vs. 14.3 (9.3-29.2) ng/mL, P=0.009, respectively]. Left ventricular ejection fraction (LVEF) was similar in both groups before and after surgery.

Conclusions

In the absence of documented myocardial infarction, T1 mapping did not identify structural tissue damage after surgical revascularization with or without cardiopulmonary bypass (CPB), despite the excessive release of cardiac biomarkers.

P598T1 mapping and myocardial extracellular volume assessed by cardiac magnetic resonance in diabetic patients with stable coronary artery disease

Background

T1 mapping is a quantitative technique of cardiac magnetic resonance (CMR) increasingly used for characterization of the myocardium. Type 2 diabetes mellitus (T2DM) may impact myocardial tissue structure, however studies that assessed this association using non-invasive methods have conflicting results.

Purpose

We sought to compare the tissue characteristics of the non-infarcted myocardium of patients with and without diabetes with multivessel CAD.

Methods

Patients with stable multivessel CAD and preserved left ventricular ejection fraction (LVEF), included in the MASS V trial, underwent contrast-enhanced CMR before revascularization procedures. Patients were stratified according to the T2DM diagnosis at baseline. Values of myocardial native T1, post-contrast T1 and extracellular volume fraction (ECV) were compared between diabetic and non-diabetic patients. Only myocardial tissue without late gadolinium enhancement were assessed.

Results

Of 155 patients studied, 67 (43%) were diabetic and 88 (57%) non-diabetic. Baseline characteristics were similiar between groups (age 70±10 vs 69±11; 69% vs 68% males; LVEF 65±13 vs 67±9). Mean Syntax score was 21.2±8.5 and 20.4±8.5 (p=0.52) in diabetic and non-diabetic, respectively. Myocardial native T1 values showed no diference in diabetic and non-diabetic (1013±67.9 vs 1015±61.4, p=0.72). However, in diabetic patients values of post-contrast T1 were significantly lower (482.2±43.8 vs 499.4±47.2, p=0.024) and ECV were higher (29.62±6.61 vs 27.08. ± 4.22, p=0.004). Multivariable analyses adjusted for age, sex, BMI, hypertension and Syntax score showed no differences in the results.

Figure1

Conclusion

In this study, T2DM was associated with higher ECV and lower post-contrast T1 values in the myocardial tissue. These findings suggest an increase in the myocardial intersticial matrix in patients with diabetes and stable multivessel CAD.

P1832Myocardial injury assessed by T1 mapping after on-pump and off-pump coronary artery bypass grafting. a pre-specified analysis of mass V trial

Background

Myocardial structural damage may occur during coronary artery bypass grafting (CABG) surgery and is identified by the significant release of cardiac biomarkers. However, the evidence of these structural myocardial changes after CABG by current imaging methods remains unknown. To evaluate myocardial structure, we used the T1 mapping of cardiac magnetic resonance (CMR) before and after on-pump and off-pump CABG.

Methods

Patients with multivessel coronary artery disease and preserved ventricular function were included and underwent on or off-pump CABG. CMR and T1 mapping were performed using the MOLLI technique (modified Look-Locker inversion-recovery). Values of native T1 and extracellular volume fraction (ECV) were compared before and after on and off-pump procedures.

Results

Of 110 eligible patients, 34 were excluded due to the presence of new late enhancement or edema. Of 76 patients remained, 32 (42%) underwent on-pump (Group A) and 44 (58%) off-pump CABG (Group B). All baseline characteristics were similar between groups, besides the Syntax Score that was higher in Group A (25 × 21, p=0.002). For group A, native T1 before and after procedures was 1013 ms (998–1043) and 1004 ms (793–1048), p=0.19, and ECV was 26.4 (23.9–27.6) and 31.2 (27.6–33.9), p<0.001. For group B, native T1 before and after procedures was 1015 ms (970–1044) and 992 ms (867–1051), p=0.003, and ECV 27.5 (25.3–29.9) and 30.3 (26.5–34.3), p=0.02. The comparison of native T1 difference before and after procedures between groups A and B was not significant (Delta T1 −9.8 (−102 to 51.8) × −25.4 (−119 to 51,2), p=0.87. However, the difference of ECV between groups was statistically significant (ECV Delta 3.8 (2.2 to 7.1) × 1.3 (−1.1 to 4.9), p=0.039, respectively, for groups A and B.

Figure 1

Conclusion

In this sample, T1 mapping identified significant myocardial structural changes in both surgical revascularization procedures. Additionally, a marked myocardial injury generated by ECV changes were observed after on-pump CABG.