Abstract
Acute coronary syndrome (ACS) encompasses a spectrum of clinical conditions associated with reduced blood supply to the myocardium. In UK and other developed countries, although the incidence is decreasing but it is still the leading cause of premature death worldwide.(1) Over the last three decades, cardiac magnetic resonance imaging (CMR) has emerged as a promising non-invasive modality in the assessment of patients with suspected and established ACS due to its good spatial resolution, high reproducibility, and myocardial tissue characterization capabilities, thereby aiding in the diagnosis, guiding clinical decision-making, and improving risk stratification.In this thesis we primarily looked at 2 cohort of patients A) Myocardial infarction with non-obstructed coronaries(MINOCA) group (388 subjects) and B) ST segment elevation myocardial infarction (STEMI) cohort 30subjects) treated with primary percutaneous coronary intervention. The findings of the acute revascularised STEMI was compared with 20 healthy volunteers and 30 subjects with previous myocardial infarction. All participants underwent CMR in a 1.5T Avanto, Siemens Scanner.
MINOCA study - In a large cohort of MINOCA, CMR (median 37days from presentation) established a diagnosis in almost 3/4 of cases, the most common diagnoses being myocarditis and MI, followed by cardiomyopathy.
The study demonstrated that the diagnostic value of CMR is improved significantly when carried out within 2 weeks from presentation.
CMR made a significant additive clinical impact on management and/or diagnosis in 66% of patients, with LGE being the best independent predictor of impact. Moreover, the clinical impact of CMR improved significantly when carried out within 2 weeks from presentation.
The MINOCA study also demonstrated that among the conventional risk factors and CMR characteristics, ST-segment elevation on presentation ECG and CMR diagnosis of cardiomyopathy were independent predictors of mortality in MINOCA. Combined analysis of CMR diagnosis and ECG at presentation may allow robust stratification of patient outcomes.
In STEMI – Via non-invasive advanced CMR relaxometry technique the study demonstrated that in STEMI the remote myocardium is also affected when compared to normal healthy myocardium. The native T1 in remote myocardium is an independant associate of MVO.
In a further study it was demonstrated that native T1 mapping correlates significantly with transmural extent of infarct(TEI) thereby differentiating between normal, infarcted viable, and infarcted non-viable myocardium with distinctive T1 profiles in both chronic and acute MI. Native T1 mapping performed better in chronic MI compared to acute due to the absence of myocardial oedema and microvascular obstruction. T1 mapping holds promise for viability assessment without the need for gadolinium contrast agents.
| Date of Award | 24 Mar 2020 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Chiara Bucciarelli-Ducci (Supervisor) |