Effects of Arteriovenous Fistula Ligation on Cardiac Structure and Function in Kidney Transplant Recipients.

BACKGROUND: Cardiovascular morbidity and mortality remain high in recipients of a kidney transplant. The persistence of a patent arteriovenous fistula (AVF) after transplantation may contribute to ongoing maladaptive cardiovascular remodeling. The ability to reverse this maladaptive remodeling by ligation of this AVF is unknown. We conducted the first randomized controlled trial to evaluate the effect of AVF ligation on cardiac structure and function in stable kidney transplant recipients. METHODS: In this randomized controlled trial, kidney transplant recipients (>12 months after transplantation with stable graft function) were randomized to AVF ligation or no intervention. All participants underwent cardiac magnetic resonance imaging at baseline and at 6 months. The primary outcome was the change in left ventricular (LV) mass. Secondary outcomes included changes in LV volumes, left and right atrial areas, LV ejection fraction, NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels, cardiac output/index, brachial flows (ipsilateral to AVF), and pulmonary artery velocity. RESULTS: A total of 93 patients were screened, of whom 64 met the inclusion criteria and were randomized to the AVF ligation (n=33) or control (n=31) group. Fifty-four participants completed the study: 27 in the AVF ligation group and 27 in the control group. On the second cardiac magnetic resonance scan, a mean decrease of 22.1 g (95% CI, 15.0-29.1) was observed in LV mass in the AVF ligation group compared with a small increase of 1.2 g (95% CI, -4.8 to 7.2) in the control group ( P<0.001). Significant decreases in LV end-diastolic volumes, LV end-systolic volumes, cardiac output, cardiac index, atrial volumes, and NT-proBNP were also seen in the AVF closure group ( P<0.01). No significant changes were observed in LV ejection fraction ( P=0.93) and pulmonary artery velocity ( P=0.07). No significant complications were noted after AVF ligation. No changes in estimated glomerular filtration rate or systolic and diastolic blood pressures were observed between cardiac magnetic resonance scans. CONCLUSIONS: Elective ligation of patent AVF in adults with stable kidney transplant function resulted in clinically significant reduction of LV myocardial mass. CLINICAL TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry URL: https://www.anzctr.org.au . Unique Identifier: ACTRN12613001302741.

Intracoronary ECG ST-segment recovery during primary percutaneous intervention for ST-segment myocardial infarction: insights from a cardiac MRI study.

BACKGROUND: ST-segment-resolution (STR) on surface electrocardiogram (ECG) is a good surrogate for myocardial reperfusion in patients with acute ST-segment-elevation-myocardial-infarction (STEMI). We sort to determine the optimal criteria of measuring STR on intracoronary-ECG (IC-ECG) for prediction of myocardial injury evaluated by cardiac MRI (CMR). METHODS: Measurements of IC-ECG ST-segments were performed at baseline, immediately after (early) and 15 min (late) after achieving TIMI-3 flow during primary-PCI. The degree of ST-segment-shift from baseline noted upon the IC-ECG was divided into four groups: (group 1) ST-segment-resolution >1 mm, (group 2) <30% resolution, (group 3) >50% resolution, (group 4) >70% resolution at both early and late time points. Patients had CMR at days 3 and 90 postprimary-PCI. RESULTS: Fifty two patients (aged 60 ± 11 years; 43 males) were evaluated. Early intracoronary-ECG ST-segment resolution (early IC-STR >1 mm) correlated with smaller scar mass (P = 0.003), nonviable myocardial mass (P < 0.001), and microvascular obstruction (MVO) (P = 0.004) on CMR at day 3. Ejection fraction (EF) was also better at day 3 (P = 0.026) and 90 (P = 0.039). Patients with poor early IC-STR (IC-STR <30%) conversely is associated with larger scar mass (P = 0.017), nonviable myocardial mass (P = 0.01), and MVO (P = 0.021) at day 3. This was also associated with worse EF at day 90 (P = 0.044). Neither group 3 or 4, or the late measurements of late IC-STR correlated with CMR markers of myocardial injury. CONCLUSION: The degree of early IC-STR (defined by IC-STR > 1 mm or <30%) successfully predicts myocardial damage following primary-PCI for an acute STEMI. Further studies are required to investigate its potential utility.

The role of cardiac magnetic resonance imaging following acute myocardial infarction.

BACKGROUND: Advances in the management of myocardial infarction have resulted in substantial reductions in morbidity and mortality. METHODS: However, after acute treatment a number of diagnostic and prognostic questions often remain to be answered, whereby cardiac imaging plays an essential role. RESULTS: For example, some patients will sustain early mechanical complications after infarction, while others may develop significant ventricular dysfunction. Furthermore, many individuals harbour a significant burden of residual coronary disease for which clarification of functional ischaemic status and/or viability of the suspected myocardial territory is required. CONCLUSION: Cardiac magnetic resonance (CMR) imaging is well positioned to fulfil these requirements given its unparalleled capability in evaluating cardiac function, stress ischaemia testing and myocardial tissue characterisation. This review will focus on the utility of CMR in resolving diagnostic uncertainty, evaluating early complications following myocardial infarction, assessing inducible ischaemia, myocardial viability, ventricular remodelling and the emerging role of CMR-derived measures as endpoints in clinical trials. KEY POINTS: Cardiac magnetic resonance (CMR) imaging identifies early complications after myocardial infarction. • Adenosine stress CMR can reliably assess co-existing disease in non-culprit arteries. • Assessment of infarct size and microvascular obstruction a robust prognostic indicator. • Assessment of myocardial viability is important to guide revascularisation decision-making.

Diagnostic accuracy of adenosine stress cardiovascular magnetic resonance following acute ST-segment elevation myocardial infarction post primary angioplasty.

BACKGROUND: Adenosine stress cardiovascular magnetic resonance (CMR) has been proven an effective tool in detection of reversible ischemia. Limited evidence is available regarding its accuracy in the setting of acute coronary syndromes, particularly in evaluating the significance of non-culprit vessel ischaemia. Adenosine stress CMR and recent advances in semi-quantitative image analysis may prove effective in this area. We sought to determine the diagnostic accuracy of semi-quantitative versus visual assessment of adenosine stress CMR in detecting ischemia in non-culprit territory vessels early after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). METHODS: Patients were prospectively enrolled in a CMR imaging protocol with rest and adenosine stress perfusion, viability and cardiac functional assessment 3 days after successful primary-PCI for STEMI. Three short axis slices each divided into 6 segments on first pass adenosine perfusion were visually and semi-quantitatively analysed. Diagnostic accuracy of both methods was compared with non-culprit territory vessels utilising quantitative coronary angiography (QCA) with significant stenosis defined as ≥ 70%. RESULTS: Fifty patients (age 59 ± 12 years) admitted with STEMI were evaluated. All subjects tolerated the adenosine stress CMR imaging protocol with no significant complications. The cohort consisted of 41% anterior and 59% non anterior infarctions. There were a total of 100 non-culprit territory vessels, identified on QCA. The diagnostic accuracy of semi-quantitative analysis was 96% with sensitivity of 99%, specificity of 67%, positive predictive value (PPV) of 97% and negative predictive value (NPV) of 86%. Visual analysis had a diagnostic accuracy of 93% with sensitivity of 96%, specificity of 50%, PPV of 97% and NPV of 43%. CONCLUSION: Adenosine stress CMR allows accurate detection of non-culprit territory stenosis in patients successfully treated with primary-PCI post STEMI. Semi-quantitative analysis may be required for improved accuracy. Larger studies are however required to demonstrate that early detection of non-culprit vessel ischemia in the post STEMI setting provides a meaningful test to guide clinical decision making and ultimately improved patient outcomes.

Multimodality Tachycardia-Induced Stress Testing Predicts a Low-Risk Group for Early Cardiovascular Mortality After Renal Transplantation.

BACKGROUND: Cardiovascular events remain a major cause of death in kidney transplant recipients. The optimal noninvasive workup to prevent peritransplant cardiac mortality remains contentious. METHODS: We conducted a retrospective analysis to assess the renal transplantation cardiovascular assessment protocol within a single-center population over a 5-year period. Asymptomatic patients aged less than 45 years with no history of cigarette smoking, without diabetes mellitus, and dialysis-dependent for less than 24 months did not undergo cardiac testing before listing. All other asymptomatic patients underwent a noninvasive, tachycardia-induced stress test, where a target heart rate of 85% predicted for age and gender was required. The primary endpoints were rates of acute myocardial infarction (AMI) and cardiovascular death at 30 days after renal transplantation. RESULTS: Between 2015 and 2019, 380 recipients underwent cardiac evaluation: 79 (20.8%) were deemed low cardiovascular risk and placed on the renal transplant waitlist without further assessment; 270 (71.1%) underwent a tachycardia-induced stress test; and 31 (8.1%) were deemed high risk and proceeded directly to invasive coronary angiography (ICA). In the 5-year follow-up, 3 patients (0.8%) experienced an AMI 30 days after renal transplantation, all of which occurred in the high-risk "direct to ICA" cohort. No events were documented in the low-risk cohort or in patients who had a negative tachycardia-induced stress test. There were no cardiovascular deaths within 30 days after transplantation. CONCLUSION: A negative tachycardia-induced cardiac stress test, achieving 85% of predicted heart rate, was associated with a 0% AMI rate and no cardiovascular deaths at 30 days after renal transplantation.

Long-Term Impact of Arteriovenous Fistula Ligation on Cardiac Structure and Function in Kidney Transplant Recipients: A 5-Year Follow-Up Observational Cohort Study.

Background: The long-term effects of arteriovenous fistula (AVF) ligation on cardiovascular structure following kidney transplantation remain uncertain. A prospective randomized, controlled trial (RCT) examined the effect of AVF ligation at 6 months on cardiovascular magnetic resonance imaging (CMR)-derived parameters in 27 kidney transplant recipients compared with 27 controls. A mean decrease in left ventricular mass (LVM) of 22.1 g (95% CI, 15.0 to 29.1) was observed compared with an increase of 1.2 g (95% CI, -4.8 to 7.2) in the control group (P<0.001). We conducted a long-term follow-up observational cohort study in the treated cohort to determine the evolution of CMR-derived parameters compared with those documented at 6 months post-AVF ligation. Methods: We performed CMR at long-term follow-up in the AVF ligation observational cohort from our original RCT published in 2019. Results were compared with CMR at 6 months postintervention. The coprimary end point was the change in CMR-derived LVM and LVM index at long-term follow-up from imaging at 6 months postindex procedure. Results: At a median of 5.1 years (interquartile range, 4.7-5.5 years), 17 patients in the AVF ligation group were studied with repeat CMR with a median duration to follow-up imaging of 5.1 years (IQR, 4.7-5.5 years). Statistically significant further reductions in LVM (-17.6±23.0 g, P=0.006) and LVM index (-10.0±13.0 g/m2, P=0.006) were documented. Conclusions: The benefit of AVF ligation on LVM and LVM index regression appears to persist long term. This has the potential to lead to a significant reduction in cardiovascular mortality.

Assessment of atrial septal defects in adults comparing cardiovascular magnetic resonance with transoesophageal echocardiography.

BACKGROUND: Many adult patients with secundum-type atrial septal defects (ASDs) are able to have these defects fixed percutaneously. Traditionally, this has involved an assessment of ASD size, geometry and atrial septal margins by transoesophageal echocardiography (TOE) prior to percutaneous closure. This is a semi-invasive technique, and all of the information obtained could potentially be obtained by non-invasive cardiovascular magnetic resonance (CMR). We compared the assessment of ASDs in consecutive patients being considered for percutaneous ASD closure using CMR and TOE. METHODS: Consecutive patients with ASDs diagnosed on transthoracic echocardiography (TTE) were invited to undergo both CMR and TOE. Assessment of atrial septal margins, maximal and minimal defect dimensions was performed with both techniques. Analyses between CMR and TOE were made using simple linear regression and Bland Altman Analyses. RESULTS: Total CMR scan time was 20 minutes, and comparable to the TOE examination time. A total of 20 patients (M:F = 5:15, mean age 42.8 years +/- 15.7) were included in the analyses. There was an excellent agreement between CMR and TOE for estimation of maximum defect size (R = 0.87). The anterior inferior, anterior superior and posterior inferior margins could be assessed in all patients with CMR. The posterior superior margin could not be assessed in only one patient. Furthermore, in 1 patient in whom TOE was unable to be performed, CMR was used to successfully direct percutaneous ASD closure. CONCLUSIONS: CMR agrees with TOE assessment of ASDs in the work-up for percutaneous closure. Potentially CMR could be used instead of TOE for this purpose.

Percutaneous closure of atrial septal defects leads to normalisation of atrial and ventricular volumes.

BACKGROUND: Percutaneous closure of atrial septal defects (ASDs) should potentially reduce right heart volumes by removing left-to-right shunting. Due to ventricular interdependence, this may be associated with impaired left ventricular filling and potentially function. Furthermore, atrial changes post-ASD closure have been poorly understood and may be important for understanding risk of atrial arrhythmia post-ASD closure. Cardiovascular magnetic resonance (CMR) is an accurate and reproducible imaging modality for the assessment of cardiac function and volumes. We assessed cardiac volumes pre- and post-percutaneous ASD closure using CMR. METHODS: Consecutive patients (n = 23) underwent CMR pre- and 6 months post-ASD closure. Steady state free precession cine CMR was performed using contiguous slices in both short and long axis views through the ASD. Data was collected for assessment of left and right atrial, ventricular end diastolic volumes (EDV) and end systolic volumes (ESV). Data is presented as mean +/- SD, volumes as mL, and paired t-testing performed between groups. Statistical significance was taken as p < 0.05. RESULTS: There was a significant reduction in right ventricular volumes at 6 months post-ASD closure (RVEDV: 208.7 +/- 76.7 vs. 140.6 +/- 60.4 mL, p < 0.0001) and RVEF was significantly increased (RVEF 35.5 +/- 15.5 vs. 42.0 +/- 15.2%, p = 0.025). There was a significant increase in the left ventricular volumes (LVEDV 84.8 +/- 32.3 vs. 106.3 +/- 38.1 mL, p = 0.003 and LVESV 37.4 +/- 20.9 vs. 46.8 +/- 18.5 mL, p = 0.016). However, there was no significant difference in LVEF and LV mass post-ASD closure. There was a significant reduction in right atrial volumes at 6 months post-ASD closure (pre-closure 110.5 +/- 55.7 vs. post-closure 90.7 +/- 69.3 mL, p = 0.019). Although there was a trend to a decrease in left atrial volumes post-ASD closure, this was not statistically significant (84.5 +/- 34.8 mL to 81.8 +/- 44.2 mL, p = NS). CONCLUSION: ASD closure leads to normalisation of ventricular volumes and also a reduction in right atrial volume. Further follow-up is required to assess how this predicts outcomes such as risk of atrial arrhythmias after such procedures.

Cardiac MRI assessment of left and right ventricular parameters in healthy Australian normal volunteers.

Cardiac magnetic resonance imaging (MRI) is being utilised increasingly for the purposes of cardiovascular imaging. Limited data suggest a high degree of reproducibility for parameters such as left ventricular (LV) ejection fraction (EF), mass, end-diastolic and end-systolic volumes (EDV and ESV). We sought to investigate reproducibility and establish means for these parameters in a selected normal non-Aboriginal Australian population, using cardiac MRI. Sixty normal volunteers underwent cardiac MRI investigation using a 1.5 T MRI system. Steady state free precession imaging was performed with short axis cine images through the left ventricle obtained. All images were acquired with cardiac gating. Two independent observers then analysed the data set. Data were collected for assessment of left ventricular EF, EDV, ESV, mass and right ventricular volumes. Data are presented as mean+/-S.D. Total imaging time was approximately 15 min. All patients were able to complete the full protocol. Left ventricular parameters: EF 58.5+/-8.0%, LV mass 114.2+/-40.6g, EDV 117.3+/-33.4 mls and ESV 50.0+/-22.2 mls. Right ventricular parameters: EF 45.6+/-11.6%, EDV 163.5+/-52.2 mls and ESV 89.5+/-34.3 mls. Intraclass correlation coefficients for LV: EF 0.84, LV mass 0.84, EDV 0.85 and ESV 0.89. Cardiac MRI provides high quality information about cardiac function with a high level of reproducibility. Cardiac MRI parameters in a normal non-Aboriginal Australian population are provided.

CT sizing for left atrial appendage closure is associated with favourable outcomes for procedural safety.

AIMS: We evaluated the utility of computerized tomography (CT) with respect to sizing work-up for percutaneous left atrial appendage (LAA) closure, and implications for procedural safety and outcomes. METHODS AND RESULTS: Contrast-enhanced multi-detector CT was routinely conducted to guide sizing for LAA closure in addition to transoesophageal echocardiography (TOE). Procedural safety and efficacy were prospectively assessed. Across 73 consecutive cases there were no device-related procedural complications, and no severe leaks. Systematic bias in orifice sizing by TOE vs. CT was significant on retrospective analysis (bias -3.0 mm vs. maximum diameter on CT; bias -1.1 mm vs. mean diameter on CT). Importantly, this translated to an altered device size selection in more than half of all cases, and median size predicted by CT was one interval greater than that predicted by TOE (27 mm vs. 24 mm). Of particular note, gross sizing error by TOE vs. CT was observed in at least 3.4% of cases. Degree of discrepancy between TOE and CT was correlated with LAA orifice eccentricity, orifice size, and left atrial volume. Mean orifice size by CT had the greatest utility for final Watchman device-size selection. CONCLUSIONS: In this single-centre registry of LAA closure, routine incorporation of CT was associated with excellent outcomes for procedural safety and absence of major residual leak. Mean orifice size may be preferable to maximum orifice size. A particular value of CT may be the detection and subsequent avoidance of gross sizing error by 2D TOE that occurs in a small but important proportion of cases.

Left Atrial Appendage Eccentricity and Irregularity Are Associated With Residual Leaks After Percutaneous Closure.

OBJECTIVES: Predictors of residual leak following percutaneous LAA closure were evaluated. BACKGROUND: Left atrial appendage (LAA) closure aims to exclude this structure from the circulation, typically using a circular occluder. A noncircular orifice is frequently encountered however, and fibrous remodeling of the LAA in atrial fibrillation may restrict orifice deformation. Noncircularity may thus be implicated in the occurrence of residual leak despite an appropriately oversized device. METHODS: Pre-procedural multislice computerized tomography was used to quantify LAA orifice eccentricity and irregularity. Univariate predictors of residual leak were identified with respect to the orifice, device, and relevant clinical variables, with the nature of any correlations then further evaluated. RESULTS: Eccentricity and irregularity indexes of the orifice in 31 individuals were correlated with residual leak even where the device was appropriately oversized. An eccentricity index of 0.15 predicted a residual leak with 85% sensitivity and 59% specificity. An irregularity index of 0.05 predicted a significant residual leak ≥3 mm with 100% sensitivity and 86% specificity. Orifice size, device size, degree of device oversize, left atrial volume, and pulmonary artery pressure were not predictors of residual leak. CONCLUSIONS: Eccentricity and irregularity of the LAA orifice are implicated in residual leak after percutaneous closure even where there is appropriate device over-size. Irregularity index in particular is a novel predictor of residual leak, supporting a closer consideration of orifice morphology before closure.

Utility of intravascular ultrasound in the diagnosis of ambiguous calcific left main stenoses.

Advances in coronary angiographic imaging have been recently realized with the advent of so-called flat panel technology. However, some of the limitations of coronary angiography, including the so-called pseudo-thrombus appearance of focal highly calcific coronary artery lesions remain. This case highlights the utility of intravascular ultrasound in determining the pathobiology of coronary artery lesions in select cases.

Intracoronary ECG during primary percutaneous coronary intervention for ST-segment elevation myocardial infarction predicts microvascular obstruction and infarct size.

INTRODUCTION: Microvascular obstruction (MVO) following ST-segment elevation myocardial infarction (STEMI) is associated with larger infarct size and an increased mortality. Although angiographic predictors of MVO in primary percutaneous coronary intervention (primary-PCI) setting have been identified, an earlier and objective "in-lab" predictor may be beneficial, in order to potentially influence therapies administered during primary-PCI. We hypothesised that intracoronary-electrocardiogram (IC-ECG) is a simple, objective and accurate predictor of MVO evaluated by cardiac magnetic resonance (CMR) and is comparable to myocardial blush grade (MBG) and TIMI myocardial perfusion grade (TMPG). METHOD: Intracoronary ECG was performed during primary-PCI. Intracoronary ST-segment measurement was performed before and immediately after opening of infarct-related-artery. Intracoronary ST-segment resolution (IC-STR) was defined as ≥ 1 mm improvement compared to baseline. Contrast enhanced CMR was performed at 4 and 90 days post primary-PCI. Primary endpoint was MVO on late gadolinium hyperenhancement assessed by CMR at day 4. RESULTS: Sixty-four consecutive patients (age 59 ± 11 years; 55 males) were recruited. Intracoronary ST-segment resolution correlated with MVO (p=0.005). Furthermore, IC-STR correlated with infarct-mass, non-viable-mass, peak creatinine kinase and end-systolic-volume at day 4. Intracoronary ST-segment resolution also correlated with favourable left ventricular end-diastolic-volume at day 90 (p=0.022). On multivariate analysis, IC-STR was an independent predictor of MVO. CONCLUSION: Intracoronary ST-segment resolution is a strong in-lab predictor of MVO assessed 4 days after STEMI on CMR. Furthermore, IC-STR correlates with infarct size and left ventricular remodelling at 3 months. Further studies are required to understand potential clinical utility of this tool.

Prognostic value of adenosine stress perfusion cardiac MRI with late gadolinium enhancement in an intermediate cardiovascular risk population.

BACKGROUND: The high diagnostic accuracy of adenosine stress cardiac magnetic resonance (AS-CMR) for detecting coronary artery stenoses, with high sensitivity and specificity, is well documented. Prognostic data, particularly in non-low risk study populations and for greater than 12 months of follow up, is however lacking or variable in its findings. We present prognostic data, in an intermediate cardiovascular risk cohort undergoing adenosine stress perfusion CMR, over approximately 2 years of follow up. METHODS: The study population comprised 362 patients referred for a clinically indicated stress CMR and included patients with proven coronary artery disease (CAD; n=157) or unknown CAD status, yet an intermediate cardiovascular risk profile (n=205). Perfusion imaging was performed at stress (adenosine 140 µg/kg/min) and rest on a 1.5 T system. Patient records and state-wide hospital databases were reviewed. Major adverse cardiac events--death, myocardial infarction, revascularisation or ischaemic hospitalisation--were evaluated over a median follow up of 22 months. RESULTS: Of the 362 cases, 90 had a stress perfusion CMR positive for ischaemia and experienced a MACE rate of 24%. Of the 272 negative CMR scans, 225 were also negative for late gadolinium enhancement, and in this group MACE was encountered in only 6 (2.7%) patients. Accordingly a negative stress CMR afforded a freedom from MACE of 97.3%. Freedom from death/myocardial infarction was 99.6%. CONCLUSIONS: In patients with confirmed coronary artery disease or at intermediate risk for cardiovascular events, a negative stress perfusion CMR is associated with an excellent prognosis over nearly 2 years of follow up.

An unusual cause of cardiac failure.

Left ventricular noncompaction (LVNC) is a rare cardiomyopathy characterized by deep intertrabecular recesses communicating with the main ventricular chamber. Cardiac magnetic resonance offers high spatial resolution, and thereby substantial aptitude for the diagnosis of LVNC. Additional clinically relevant information, including thrombus and myocardial fibrosis evaluation, can be readily acquired. These images demonstrate classical LVNC morphology in conjunction with its potential sequelae.

Cardiac magnetic resonance derived late microvascular obstruction assessment post ST-segment elevation myocardial infarction is the best predictor of left ventricular function: a comparison of angiographic and cardiac magnetic resonance derived measurements.

Microvascular obstruction (MVO) is a strong independent predictor of left ventricular remodelling and mortality following ST-segment elevation myocardial infarction (STEMI). Microvascular obstruction can be identified at angiography or with gadolinium-enhanced cardiac MRI (CMR). First-pass perfusion CMR also allows a novel quantitative evaluation of myocardial blood flow (MBF) that might provide superior predictive data in the assessment of MVO. We sought to compare angiographic and CMR derived methodologies in the assessment of MVO to determine the optimal methodology that best predicts the surrogate outcome marker of left ventricular function post STEMI. Following primary-PCI angiographic assessment of 'no-reflow' with TIMI myocardial perfusion grade (TMPG) and myocardial blush grade (MBG) were documented. Assessment of CMR derived MVO was assessed on day 3, with MVO on first-pass perfusion imaging termed 'early MVO' and on late gadolinium enhancement, 'late MVO'. Furthermore on the same day 3 CMR scan, myocardial blood flow in the infarct region was quantified at adenosine stress and rest utilizing standard perfusion imaging sequences. Assessment of remodelling, structure and function was undertaken via standard CMR imaging assessment on day 90 post-STEMI and was used as the surrogate marker for long term clinical outcome. Forty patients (age 59 ± 12 years, 84% males) were appraised. Late MVO had the strongest correlation with LVEF at 90 days compared to the CMR parameters of early MVO, stress infarct region MBF and rest infarct region MBF (r = -0.754, r = -0.588, r = 0.595 and r = 0.345 respectively). Of the angiographic parameters used to assess MVO, TMPG had the strongest relationship with MVO when assessed via CMR. Myocardial blush grade however showed no relationship to CMR derived assessment of MVO. On multivariate analysis, of all angiographic and CMR variables, late MVO was the strongest predictor of LVEF at 90 days (p = 0.004). Cardiac magnetic resonance imaging derived assessment of microvascular obstruction on late gadolinium enhancement strongly predicts left ventricular function following STEMI at 90 days.