Cardiovascular magnetic resonance of acute and chronic myocardial ischaemia
Author(s)
Bucciarelli-Ducci, Chiara
Type
Thesis
Abstract
BACKGROUND:
Ischaemic heart disease is the leading cause of mortality and morbidity in the developed world.
Cardiovascular magnetic resonance (CMR) is a non-invasive imaging modality providing in vivo
myocardial tissue characterisation and quantification. We aimed to validate CMR in the field of
interventional cardiology as a tool for guiding patient selection and management to the assessment
of the results of interventions both in the acute and chronic settings.
METHODS AND RESULTS:
We investigated the impact of primary angioplasty delay on the presence and extent of myocardial
salvage, microvascular obstruction and infarct size. We found that “time is muscle”, and that shorter
time to reperfusion was associated with smaller infarct size (p=0.05), less microvascular obstruction
(p=0.04) and a greater amount of salvaged myocardium (p=0.003). Microvascular obstruction was
then used as an endpoint in a prospective randomised trial assessing the impact of a thrombectomy
device as adjunctive therapy in primary PCI. The incidence and extent of microvascular damage
was significantly reduced in the thrombectomy group compared to standard primary PCI
(p=0.0005). CMR can identify 2 degrees of microvascular damage: early or persistent
microvascular dysfunction. The latter was the strongest predictor of LV remodelling (p=0.03), it
was predicted by infarct size (p=0.002), and infarct healing (shrinkage) occurred to a greater extent
(p<0.006). We validated the clinical use of CMR perfusion in a cohort of patients with chronic
coronary occlusion whose management is currently controversial. CMR identified myocardial
viability and inducible myocardial ischaemia in a significant percentage of patients, guided
revascularisation that reduced ischaemic burden (p<0.0001) with improvements in left ventricular
function (p<0.0001) and health outcome measures (p<0.0001). Finally, improved CMR perfusion
image quality was pursued with a new imaging protocol but this demonstrated increased incidence
of artefacts (p<0.001) and lower diagnostic accuracy compared to the standard technique.
CONCLUSIONS:
Cardiovascular magnetic resonance provides in vivo myocardial tissue characterisation that can
potentially not only guide treatment but also assess its effects. The result of this work suggests that
CMR could emerge as a clinical valuable technique in numerous interventional clinical settings
within acute to chronic myocardial ischaemia, in addition to providing surrogate endpoints for
clinical trials.
Ischaemic heart disease is the leading cause of mortality and morbidity in the developed world.
Cardiovascular magnetic resonance (CMR) is a non-invasive imaging modality providing in vivo
myocardial tissue characterisation and quantification. We aimed to validate CMR in the field of
interventional cardiology as a tool for guiding patient selection and management to the assessment
of the results of interventions both in the acute and chronic settings.
METHODS AND RESULTS:
We investigated the impact of primary angioplasty delay on the presence and extent of myocardial
salvage, microvascular obstruction and infarct size. We found that “time is muscle”, and that shorter
time to reperfusion was associated with smaller infarct size (p=0.05), less microvascular obstruction
(p=0.04) and a greater amount of salvaged myocardium (p=0.003). Microvascular obstruction was
then used as an endpoint in a prospective randomised trial assessing the impact of a thrombectomy
device as adjunctive therapy in primary PCI. The incidence and extent of microvascular damage
was significantly reduced in the thrombectomy group compared to standard primary PCI
(p=0.0005). CMR can identify 2 degrees of microvascular damage: early or persistent
microvascular dysfunction. The latter was the strongest predictor of LV remodelling (p=0.03), it
was predicted by infarct size (p=0.002), and infarct healing (shrinkage) occurred to a greater extent
(p<0.006). We validated the clinical use of CMR perfusion in a cohort of patients with chronic
coronary occlusion whose management is currently controversial. CMR identified myocardial
viability and inducible myocardial ischaemia in a significant percentage of patients, guided
revascularisation that reduced ischaemic burden (p<0.0001) with improvements in left ventricular
function (p<0.0001) and health outcome measures (p<0.0001). Finally, improved CMR perfusion
image quality was pursued with a new imaging protocol but this demonstrated increased incidence
of artefacts (p<0.001) and lower diagnostic accuracy compared to the standard technique.
CONCLUSIONS:
Cardiovascular magnetic resonance provides in vivo myocardial tissue characterisation that can
potentially not only guide treatment but also assess its effects. The result of this work suggests that
CMR could emerge as a clinical valuable technique in numerous interventional clinical settings
within acute to chronic myocardial ischaemia, in addition to providing surrogate endpoints for
clinical trials.
Date Issued
2012
Date Awarded
2012-09
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Firmin, David
Pennell, Dudley
Publisher Department
National Heart and Lung Institute
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)