Prognostic value of coronary revascularisation-related myocardial injury: a cardiac magnetic resonance imaging study

Abstract

Aims: Myocardial revascularisation improves outcomes in patients with coronary artery disease. However, these procedures may themselves cause irreversible myocardial injury. The prognostic value of procedural myocardial injury is uncertain. Methods and results: We quantified procedural myocardial necrosis using delayed enhancement cardiovascular magnetic resonance imaging (DE-CMR) in 152 consecutive patients before and shortly after percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG). The primary endpoint was defined as death, non-fatal myocardial infarction, sustained ventricular arrhythmia, unstable angina or heart failure requiring hospitalisation. During a median follow-up of 2.9 years, 27 patients (18%) reached the primary endpoint. 49 patients (32%) had evidence of new procedure-related myocardial hyperenhancement with a median mass of 5.0 g (interquartile range 2.7-9.8). After adjustment for age and sex, these patients had a 3.1-fold (95% confidence interval 1.4 to 6.8; p = 0.004) higher risk of adverse outcome than patients without new hyperenhancement. Cardiac troponin levels and quantitative measures of left ventricular function after procedure did not show any significant independent association with the primary endpoint and they did not alter the independent association of new hyperenhancement. Conclusions: Myocardial injury during PCI or CABG, identified by DE-CMR, adversely affects clinical outcome. This suggests the benefits from revascularisation could partially be offset by new myocardial injury caused by the intervention itself.A rise in cardiac biomarkers occurs in nearly all patients undergoing coronary artery bypass graft (CABG) surgery 1 and in up to 40% of patients undergoing percutaneous coronary intervention (PCI).2 The most recent joint European Society of Cardiology (ESC)/American College of Cardiology (ACC)/American Heart Association (AHA)/World Heart Federation (WHF) task force guidelines recognise elevation of cardiac biomarkers of more than three times the 99th percentile upper reference limit (URL) following PCI and more than five times the 99th percentile URL after CABG in the definition of procedure-related myocardial infarction. 3 However, controversy remains over the independent prognostic value of rises in biomarkers after revascularisation. Although biomarkers such as troponin have a high accuracy in detection of myocardial tissue loss and have been shown to be of prognostic value in several acute and non-acute settings, the demonstration of their prognostic value after coronary revascularisation has been hampered for several reasons: troponin elevations after revascularisation are often very small and the cut-offs for abnormal values variable across studies; many patients undergoing elective revascularisation have some degree of troponin elevation before the procedure 6 7; the inherent delay in rise of biomarkers may affect the correct ascertainment of sequence of events, 8 in particular when revascularisation itself can lead to biomarke...

The randomised Complete versus Lesion-only PRimary percutaneous coronary Intervention Trial: Cardiovascular Magnetic Resonance imaging substudy (CvLPRIT-CMR)

“…24 Such type 4a MI 81 can be detected on CMR scans and have been associated with adverse prognosis. 27 In this substudy of the CvLPRIT, the prevalence of > 1 CMR imaging-detected infarct in patients receiving CR was double that in the IRA-only arm (23.8% vs. 11.2% respectively), and more than threefold for the acute non-IRA infarcts (17.1% CR vs. 4.8% IRA only). Previous Q-wave MI was an exclusion criterion in this study, but 4% of the CR group and 3% in the IRA-only group had a history of previous non-STEMI.…”

“…In the main CvLPRIT, 80 CR resulted in a significantly reduced HR for the 12-month combined MACEs, despite the greater prevalence of CMR imaging-detected type 4a MI shown in the current results. There are limited data on whether or not revascularisation-induced myocardial injury detected by CMR imaging is linked to prognosis 27 and no data in patients presenting with STEMI. In an observational study of 152 patients undergoing elective revascularisation, 32% had evidence of new LGE which averaged 5 g (≈4% of LVM), but half of these patients were treated with a CABG.…”

“…However, this proportion is less than that might have been expected from previous studies in elective PCI. 24,27 The extent of acute non-IRA infarction was generally small (median 2.5% of LVM). Importantly, total IS was not increased at baseline or at follow-up, and there were no significant differences in LV volumes or ejection fraction between the treatment groups.…”

“…26 In a mixed cohort of patients undergoing elective PCI (n = 92) or coronary artery bypass grafting (n = 60), those who experienced new myocardial injury, detectable on cardiac magnetic resonance (CMR) imaging, had a threefold increase in MACEs. 27 There is also the not insignificant, but impossible to quantify, risk of complete no-reflow in the non-IRA which could have devastating consequences in a patient undergoing the PPCI. There are no data available that tell us the frequency of 'new' injury in the non-IRA with multivessel PPCI, but we can anticipate this will be significantly higher than in patients undergoing elective PCI.…”

“…A new IS of 4% of LVM is associated with adverse prognosis in CAD patients with revascularisation-related injury. 27 …”