'Super Rehab': can we achieve coronary artery disease regression? A feasibility study protocol.

INTRODUCTION: Patients diagnosed with coronary artery disease (CAD) are currently treated with medications and lifestyle advice to reduce the likelihood of disease progression and risk of future major adverse cardiovascular events (MACE). Where obstructive disease is diagnosed, revascularisation may be considered to treat refractory symptoms. However, many patients with coexistent cardiovascular risk factors, particularly those with metabolic syndrome (MetS), remain at heightened risk of future MACE despite current management.Cardiac rehabilitation is offered to patients post-revascularisation, however, there is no definitive evidence demonstrating its benefit in a primary prevention setting. We propose that an intensive lifestyle intervention (Super Rehab, SR) incorporating high-intensity exercise, diet and behavioural change techniques may improve symptoms, outcomes, and enable CAD regression.This study aims to examine the feasibility of delivering a multicentre randomised controlled trial (RCT) testing SR for patients with CAD, in a primary prevention setting. METHODS AND ANALYSIS: This is a multicentre randomised controlled feasibility study of SR versus usual care in patients with CAD. The study aims to recruit 50 participants aged 18-75 across two centres. Feasibility will be assessed against rates of recruitment, retention and, in the intervention arm, attendance and adherence to SR. Qualitative interviews will explore trial experiences of study participants and practitioners. Variance of change in CAD across both arms of the study (assessed with serial CT coronary angiography) will inform the design and power of a future, multi-centre RCT. ETHICS AND DISSEMINATION: Ethics approval was granted by South West-Frenchay Research Ethics Committee (reference: 21/SW/0153, 18 January 2022). Study findings will be disseminated via presentations to relevant stakeholders, national and international conferences and open-access peer-reviewed research publications. TRIAL REGISTRATION NUMBER: ISRCTN14603929.

CMR reclassifies the majority of patients with suspected MINOCA and non MINOCA.

AIMS: In ∼5-15% of all cases of acute coronary syndromes (ACS) have unobstructed coronaries on angiography. Cardiac magnetic resonance (CMR) has proven useful to identify in most patients the underlying diagnosis associated with this presentation. However, the role of CMR to reclassify patients from the initial suspected condition has not been clarified. The aim of this study was to assess the proportion of patients with suspected MINOCA, or non-MINOCA, that CMR reclassifies with an alternative diagnosis from the original clinical suspicion. METHODS AND RESULTS: A retrospective cohort of patients in a tertiary cardiology centre was identified from a registry database. Patients who were referred for CMR for investigation of suspected MINOCA, and a diagnosis pre- and post-CMR was recorded to determine the proportion of diagnoses reclassified. A total of 888 patients were identified in the registry. CMR reclassified diagnosis in 78% of patients. Diagnosis of MINOCA was confirmed in only 243 patients (27%), whilst most patients had an alternative diagnosis (73%): myocarditis n = 217 (24%), Takotsubo syndrome n = 115 (13%), cardiomyopathies n = 97 (11%), and normal CMR/non-specific n = 216 (24%). CONCLUSION: In a large single-centre cohort of patients presenting with ACS and unobstructed coronary arteries, most patients had a non-MINOCA diagnosis (73%) (myocarditis, Takotsubo, cardiomyopathies, or normal CMR/non-specific findings), whilst only a minority had confirmed MINOCA (27%). Performing CMR led to reclassifying patients' diagnosis in 78% of cases, thus confirming its important clinical role and underscoring the clinical challenge in diagnosing MINOCA and non MINOCA conditions.

Artificial Intelligence as a Diagnostic Tool in Non-Invasive Imaging in the Assessment of Coronary Artery Disease.

Coronary artery disease (CAD) remains a leading cause of mortality and morbidity worldwide, and it is associated with considerable economic burden. In an ageing, multimorbid population, it has become increasingly important to develop reliable, consistent, low-risk, non-invasive means of diagnosing CAD. The evolution of multiple cardiac modalities in this field has addressed this dilemma to a large extent, not only in providing information regarding anatomical disease, as is the case with coronary computed tomography angiography (CCTA), but also in contributing critical details about functional assessment, for instance, using stress cardiac magnetic resonance (S-CMR). The field of artificial intelligence (AI) is developing at an astounding pace, especially in healthcare. In healthcare, key milestones have been achieved using AI and machine learning (ML) in various clinical settings, from smartwatches detecting arrhythmias to retinal image analysis and skin cancer prediction. In recent times, we have seen an emerging interest in developing AI-based technology in the field of cardiovascular imaging, as it is felt that ML methods have potential to overcome some limitations of current risk models by applying computer algorithms to large databases with multidimensional variables, thus enabling the inclusion of complex relationships to predict outcomes. In this paper, we review the current literature on the various applications of AI in the assessment of CAD, with a focus on multimodality imaging, followed by a discussion on future perspectives and critical challenges that this field is likely to encounter as it continues to evolve in cardiology.

Sex differences in patients with acute coronary syndromes and non-obstructive coronary arteries: Presentation and outcome.

BACKGROUND: A substantial number of patients present with a suspected ACS and non-obstructive coronary arteries; sex differences in these patients are not well understood. This study aims to evaluate the impact of sex on clinical presentation and outcome in patients with suspected acute coronary syndrome (ACS) and non-obstructive coronary arteries with a final diagnosis confirmed by cardiovascular magnetic resonance imaging (CMR). METHODS: Consecutive patients with ACS and non-obstructive coronary arteries (n = 719) with an unclear cause from a single tertiary centre who were referred for CMR were included. The primary endpoint was all-cause mortality. RESULTS: CMR was performed at a median time of 30 days after presentation and identified a diagnosis in 74% of patients. All-cause mortality was 9.5% over a median follow up of 4.9 years, with no significant difference between sexes (8.8% versus 10.1%; p = 0.456). Men were more likely to have non-ischaemic aetiology on CMR than women (55% v 41%, p < 0.001), but were equally likely to have an ischaemic cause (25% v 27%, p = 0.462). Age group (HR 1.58, p < 0.001) and LV ejection fraction (HR 0.98, p = 0.023) were independent predictors of mortality. CONCLUSIONS: There is no difference in all-cause mortality between sexes in patients presenting with suspected ACS and non-obstructive coronary arteries.

Validation of the MIRACLE2 Score for Prognostication After Out-of-hospital Cardiac Arrest.

Background: Out-of-hospital cardiac arrest (OHCA) is associated with very poor clinical outcomes. An optimal pathway of care is yet to be defined, but prognostication is likely to assist in the challenging decision-making required for treatment of this high-risk patient cohort. The MIRACLE2 score provides a simple method of neuro-prognostication but as yet it has not been externally validated. The aim of this study was therefore to retrospectively apply the score to a cohort of OHCA patients to assess the predictive ability and accuracy in the identification of neurological outcome. Methods: Retrospective data of patients identified by hospital coding, over a period of 18 months, were collected from a large tertiary-level cardiac centre with a mature, multidisciplinary OHCA service. MIRACLE2 score performance was assessed against three existing OHCA prognostication scores. Results: Patients with all-comer OHCA, of presumed cardiac origin, with and without evidence of ST-elevation MI (43.4% versus 56.6%, respectively) were included. Regardless of presentation, the MIRACLE2 score performed well in neuro-prognostication, with a low MIRACLE2 score (≤2) providing a negative predictive value of 94% for poor neurological outcome at discharge, while a high score (≥5) had a positive predictive value of 95%. A high MIRACLE2 score performed well regardless of presenting ECG, with 91% of patients receiving early coronary angiography having a poor outcome. Conclusion: The MIRACLE2 score has good prognostic performance and is easily applicable to cardiac-origin OHCA presentation at the hospital front door. Prognostic scoring may assist decision-making regarding early angiographic assessment.

Peak Troponin and CMR to Guide Management in Suspected ACS and Nonobstructive Coronary Arteries.

BACKGROUND: Patients presenting with acute coronary syndrome (ACS) and nonobstructive coronary arteries are a diagnostic dilemma. Cardiac magnetic resonance (CMR) has an overall diagnostic yield of ∼75%; however, in ∼25% of patients, CMR does not identify any myocardial injury. Identifying the underlying diagnosis has important clinical implications for patients' management and outcome. OBJECTIVES: The authors sought to assess whether the combination of CMR and peak troponin levels in patients with ACS and nonobstructive coronary arteries would lead to increased diagnostic yield. METHODS: Consecutive patients with ACS and nonobstructive coronary arteries without an obvious cause underwent CMR. The primary endpoint of the study was the diagnostic yield of CMR. The Youden index was used to find the optimal diagnostic cut point for peak troponin T to combine with CMR to improve diagnostic yield. Logistic or Cox regression models were used to estimate predictors of a diagnosis by CMR. RESULTS: A total of 719 patients met the inclusion criteria. The peak troponin T threshold for optimal diagnostic sensitivity and specificity was 211 ng/L. Overall, CMR has a diagnostic yield of 74%. CMR performed <14 days from presentation and with a peak troponin of ≥211 ng/L (n = 198) leads to an improved diagnostic yield (94% vs 72%) compared with CMR performed ≥14 days (n = 245). When CMR was performed <14 days and with a peak troponin of <211 ng/L, the diagnostic yield was 76% (n = 86) compared with 53% (n = 190) when performed ≥14 days. An increase in 1 peak troponin decile increases the odds of the CMR identifying a diagnosis by 20% (OR: 1.20; P = 0.008, 95% CI: 1.05-1.36). CONCLUSIONS: The combination of CMR performed <14 days from presentation and peak troponin T ≥211 ng/L leads to a very high diagnostic yield (94%) on CMR. The diagnostic yield remains high (72%) even when CMR is performed ≥14 days from presentation, but reduces to 53% when peak troponin T was <211 ng/L.

Assessing splenic switch-off in Adenosine stress CMR for patients with atrial fibrillation: a propensity-matched study.

OBJECTIVES: Splenic switch-off (SSO) is a validated indicator of adequate vasodilator stress unique to adenosine stress cardiac MR (CMR). Patients in atrial fibrillation (AF) may have a reduced adenosine response due to lower hyperaemic coronary flow reserve and may achieve SSO less frequently versus sinus rhythm (SR). METHODS: 1100 stress CMR studies were identified from a clinical CMR database (2016-2021). 70 patients in AF were propensity score matched to a SR group for age, sex, and body mass index. The adenosine dose administered, symptoms, heart-rate change and scan result were recorded. SSO was evaluated subjectively and semi-quantitatively via changes in splenic and myocardial signal intensity (SI) from rest to stress. RESULTS: SSO occurred significantly less frequently in AF than SR (34/70 [49%] vs 53/70 [76%], p = 0.003). Semi-quantitative assessment supported this, with a smaller splenic SI difference between stress and rest in AF vs SR (median splenic stress:rest peak SI ratio 0.92 [IQR:0.61-1.11] vs 0.56 [IQR:0.45-0.75], p < 0.001). A heart-rate increase >10 bpm predicted visual SSO in SR but not AF. Fewer patients in AF than SR had inducible ischaemia (9/70 [13%] vs 17/69 [25%], p = 0.058). This difference was not driven by inducible ischaemia rates in patients who did not achieve SSO (6/36 [17%] AF vs 4/17 [24%] SR, p = 0.403). CONCLUSIONS: SSO occurs significantly less frequently with AF. This may risk the under diagnosis of inducible ischaemia and requires further assessment. ADVANCES IN KNOWLEDGE: SSO, a validated marker of adequate stress in CMR, occurs significantly less frequently in the presence of AF, risking a suboptimal functional assessment of coronary disease.

Mitral regurgitation quantified by CMR 4D-flow is associated with microvascular obstruction post reperfused ST-segment elevation myocardial infarction.

OBJECTIVES: Mitral regurgitation (MR) and microvascular obstruction (MVO) are common complications of myocardial infarction (MI). This study aimed to investigate the association between MR in ST-elevation MI (STEMI) subjects with MVO post-reperfusion. STEMI subjects undergoing primary percutaneous intervention were enrolled. Cardiovascular magnetic resonance (CMR) imaging was performed within 48-hours of initial presentation. 4D flow images of CMR were analysed using a retrospective valve tracking technique to quantify MR volume, and late gadolinium enhancement images of CMR to assess MVO. RESULTS: Among 69 patients in the study cohort, 41 had MVO (59%). Patients with MVO had lower left ventricular (LV) ejection fraction (EF) (42 ± 10% vs. 52 ± 8%, P < 0.01), higher end-systolic volume (98 ± 49 ml vs. 73 ± 28 ml, P < 0.001) and larger scar volume (26 ± 19% vs. 11 ± 9%, P < 0.001). Extent of MVO was associated with the degree of MR quantified by 4D flow (R = 0.54, P = 0.0003). In uni-variate regression analysis, investigating the association of CMR variables to the degree of acute MR, only the extent of MVO was associated (coefficient = 0.27, P = 0.001). The area under the curve for the presence of MVO was 0.66 (P = 0.01) for MR > 2.5 ml. We conclude that in patients with reperfused STEMI, the degree of acute MR is associated with the degree of MVO.

Percutaneous coronary intervention in octogenarians: 10-year experience from a primary percutaneous coronary intervention centre with off-site cardiothoracic support.

OBJECTIVE: To examine the trends in patient characteristics and clinical outcomes over a ten-year period and to analyse the predictors of mortality in octogenarians undergoing percutaneous coronary intervention (PCI) in our centre. METHODS: A total of 782 consecutive octogenarians (aged 80 and above) were identified from a prospectively collected PCI database within our non-surgical, medium volume centre between 1st January 2007 and 31st December 2016. This represented 10.9% of all PCI procedures performed in our centre during this period. We evaluated the demographic and procedural characteristics of the cohort with respect to clinical outcomes (all-cause in-hospital and 1-year mortality, in-hospital complication rates, duration of hospital admission, coronary disease angiographic complexity and major co-morbidities). The cohort was further stratified into three chronological tertiles (January 2007 to July 2012, 261 cases; August 2012 to May 2015, 261 cases; June 2015 to December 2016, 260 cases) to assess for differences over time. Predictors of mortality were identified through a multivariate regression analysis. RESULTS: The number of octogenarians undergoing PCI increased nearly ten-fold over the studied period. Despite this, there were no significant differences in clinical outcomes or patient characteristics, except for the increased use of trans-radial vascular access [11.9% in first tertile vs. 73.2% in third tertile (P < 0.0001)]. The all-cause in-hospital (5.8% vs. 4.6% vs. 3.8%, P = 0.578) and 1-year mortality (12.4% vs. 12.5% vs. 14.4%, P = 0.746) remained constant in all three tertiles respectively. Six independent predictors of mortality were identified - increasing age [HR = 1.12 (1.03-1.22), P = 0.008], cardiogenic shock [HR = 16.40 (4.04-66.65), P < 0.0001], severe left ventricular impairment [HR = 3.52 (1.69-7.33), P = 0.001], peripheral vascular disease [HR = 2.73 (1.22-6.13), P = 0.015], diabetes [HR = 2.59 (1.30-5.17), P = 0.007] and low creatinine clearance [HR = 0.98 (0.96-1.00), P = 0.031]. CONCLUSION: This contemporary observational study provides a useful insight into the real-world practice of PCI in octogenarians.

Myocardial inflammation and energetics by cardiac MRI: a review of emerging techniques.

The role of inflammation in cardiovascular pathophysiology has gained a lot of research interest in recent years. Cardiovascular Magnetic Resonance has been a powerful tool in the non-invasive assessment of inflammation in several conditions. More recently, Ultrasmall superparamagnetic particles of iron oxide have been successfully used to evaluate macrophage activity and subsequently inflammation on a cellular level. Current evidence from research studies provides encouraging data and confirms that this evolving method can potentially have a huge impact on clinical practice as it can be used in the diagnosis and management of very common conditions such as coronary artery disease, ischaemic and non-ischaemic cardiomyopathy, myocarditis and atherosclerosis. Another important emerging concept is that of myocardial energetics. With the use of phosphorus magnetic resonance spectroscopy, myocardial energetic compromise has been proved to be an important feature in the pathophysiological process of several conditions including diabetic cardiomyopathy, inherited cardiomyopathies, valvular heart disease and cardiac transplant rejection. This unique tool is therefore being utilized to assess metabolic alterations in a wide range of cardiovascular diseases. This review systematically examines these state-of-the-art methods in detail and provides an insight into the mechanisms of action and the clinical implications of their use.

Clinical Translation of Three-Dimensional Scar, Diffusion Tensor Imaging, Four-Dimensional Flow, and Quantitative Perfusion in Cardiac MRI: A Comprehensive Review.

Cardiovascular magnetic resonance (CMR) imaging is a versatile tool that has established itself as the reference method for functional assessment and tissue characterisation. CMR helps to diagnose, monitor disease course and sub-phenotype disease states. Several emerging CMR methods have the potential to offer a personalised medicine approach to treatment. CMR tissue characterisation is used to assess myocardial oedema, inflammation or thrombus in various disease conditions. CMR derived scar maps have the potential to inform ablation therapy-both in atrial and ventricular arrhythmias. Quantitative CMR is pushing boundaries with motion corrections in tissue characterisation and first-pass perfusion. Advanced tissue characterisation by imaging the myocardial fibre orientation using diffusion tensor imaging (DTI), has also demonstrated novel insights in patients with cardiomyopathies. Enhanced flow assessment using four-dimensional flow (4D flow) CMR, where time is the fourth dimension, allows quantification of transvalvular flow to a high degree of accuracy for all four-valves within the same cardiac cycle. This review discusses these emerging methods and others in detail and gives the reader a foresight of how CMR will evolve into a powerful clinical tool in offering a precision medicine approach to treatment, diagnosis, and detection of disease.

Acute coronary occlusion after surgical replacement of the aortic valve treated with emergency off-pump coronary artery bypass grafting.

Acute coronary occlusion after surgical replacement of the aortic valve is a rare but potentially fatal event. Due to its rarity, there is no univocal treatment with the percutaneous approach being the most commonly used for its promptness and ease of use. Only a few cases have been treated with coronary artery bypass grafting (CABG) and, to the best of our knowledge, none has been reported with the use of off-pump CABG (OPCABG). Here we describe the case of acute coronary occlusion of the circumflex artery immediately after surgical replacement of the aortic valve in a 79-year-old patient. The occlusion was promptly diagnosed and treated with interval emergency balloon angioplasty followed by OPCABG of the circumflex artery. The patient made a full recovery and was discharged home 12 days after the surgery.

Simultaneous spontaneous arterial dissections in a 38-year-old woman presenting during the covid-19 pandemic: a case report.

BACKGROUND: Spontaneous coronary artery dissection (SCAD) is an increasingly recognized and important cause of acute myocardial infarction, particularly in women under 50, often with minimal risk factors. Many patients have underlying arteriopathy, most commonly in the form of fibromuscular dysplasia. CASE SUMMARY: A 38-year-old woman presented to the hospital with chest pain and elevated high-sensitivity Troponin. Invasive coronary angiography demonstrated SCAD of the left anterior descending artery. The same day the patient developed a severe progressive headache and subsequent imaging revealed a left vertebral artery dissection. She was managed conservatively with optimal medical therapy and was successfully discharged from hospital on Day 7. DISCUSSION: To our knowledge, this is the first case report of simultaneous spontaneous coronary and vertebral artery dissections not related to pregnancy. It highlights not only the importance of recognizing and accurately diagnosing SCAD, but also of appreciating the possibility of underlying arteriopathy: this is paramount to ensuring appropriate investigations, follow-up and assessment of any unexplained symptoms in this patient group.

Impact of COVID-19 on inpatient referral of acute heart failure: a single-centre experience from the south-west of the UK.

AIMS: Healthcare services worldwide have been significantly impacted by the COVID-19 pandemic. Recent reports have shown a decline in hospitalization for emergency cardiac conditions. The impact of the COVID-19 pandemic on hospitalization and particularly mortality due to acute heart failure has not been thoroughly described. METHODS AND RESULTS: In this single-centre observational study, we examined referrals to the acute heart failure team over a period of 16 weeks (7 January to 27 April 2020) spanning the ongoing COVID-19 pandemic; 283 patients referred to our acute heart failure services over the study period were included on the basis of typical symptoms, raised BNP, and echocardiogram. There was a substantial but statistically non-significant drop in referrals with 164 referred in the 8 weeks before the first UK death due to COVID-19 on 2 March 2020 (BC), compared with 119 referred after (AC) in the subsequent 8 weeks, representing a 27% reduction overall (P = 0.06). The 30 day case fatality rate was increased from 11% in the BC group compared with 21% in the AC group (risk ratio = 1.9, 95% confidence interval 1.09-3.3). Age, gender, length of stay, left ventricular ejection fraction, and N-terminal pro-brain natriuretic peptide were similar between the groups. Admission creatinine, age, and AC cohort status were found to be univariable predictors of mortality. On multivariate Cox regression analysis, only age (hazard ratio 1.04, P = 0.03) and AC cohort status (hazard ratio 2.1, P = 0.017) remained significant predictors of mortality. On sensitivity analysis, this increased mortality was driven by COVID-19 positive status. CONCLUSIONS: There was a reduction in referral of patients with acute heart failure with significant increase in mortality in the 8 weeks following the first reported UK death due to COVID-19. The observation of increased mortality does not appear related to a change in population in terms of demographics, left ventricular ejection fraction, or N-terminal pro-brain natriuretic peptide. The observed increased mortality appears to be related to the coexistence of COVID19 infection with acute heart failure. The study highlights the need for widespread preventative and shielding measures particularly in this group of patients especially in the light of the second wave. Longer follow-up with inclusion of data from other centres and community heart failure services will be needed.

Long-term outcome of myocardial scarring and deformation with cardiovascular magnetic resonance in out of hospital cardiac arrest survivors.

AIMS: Cardiovascular magnetic resonance (CMR) is increasingly recognized as a diagnostic and prognostic tool in out of hospital cardiac arrest (OHCA) survivors. After assessing CMR findings early after ventricular fibrillation (VF) OHCA, we sought to explore the long-term outcome of myocardial scarring and deformation. METHODS AND RESULTS: We included 121 consecutive VF OHCA survivors (82% male, median 62 years) undergoing CMR within 2 weeks from cardiac arrest. Late gadolinium-enhancement (LGE) was quantified using the full width at half maximum method and tissue tracking analysis software was used to assess myocardial deformation. LGE was found in 71% of patients (median LGE mass 6.2% of the left ventricle, LV), mainly with an ischaemic pattern. Myocardial deformation was overall impaired and showed a significant correlation with LGE presence and extent (P < 0.001). A composite end-point of all-cause mortality and appropriate ICD discharge/anti-tachycardia pacing was met in 24% of patients. Patients meeting the end-point had significantly greater LGE extent (8.6% of LV myocardium vs. 4.1%, P = 0.02), while there was no difference with regards to myocardial deformation. Survival rate was significantly lower in patients with LGE (P = 0.05) and LGE mass >4.4% of the LV identified a group of patients at higher risk of adverse events (P = 0.005). CONCLUSIONS: We found a high prevalence of LGE, early after OHCA, and an overall impaired myocardial deformation. On long-term follow-up both LGE presence and extent showed a significant association with recurrent adverse events, while LV ejection fraction and myocardial deformation did not identify patients with an unfavourable outcome.

Meta-analysis of echocardiographic quantification of left ventricular filling pressure.

AIMS: The clinical reliability of echocardiographic surrogate markers of left ventricular filling pressures (LVFPs) across different cardiovascular pathologies remains unanswered. The main objective was to evaluate the evidence of how effectively different echocardiographic indices estimate true LVFP. METHODS AND RESULTS: Design: this is a systematic review and meta-analysis. DATA SOURCE: Scopus, PubMed and Embase. Eligibility criteria for selecting studies were those that used echocardiography to predict or estimate pulmonary capillary wedge pressure or left ventricular end-diastolic pressures. Twenty-seven studies met criteria. Only eight studies (30%) reported both correlation coefficient and bias between non-invasive and invasively measured LVFPs. The majority of studies (74%) recorded invasive pulmonary capillary wedge pressure as a surrogate for left ventricular end-diastolic pressures. The pooled correlation coefficient overall was r = 0.69 [95% confidence interval (CI) 0.63-0.75, P < 0.01]. Evaluation by cohort demonstrated varying association: heart failure with preserved ejection fraction (11 studies, n = 575, r = 0.59, 95% CI 0.53-0.64) and heart failure with reduced ejection fraction (8 studies, n = 381, r = 0.67, 95% CI 0.61-0.72). CONCLUSIONS: Echocardiographic indices show moderate pooled association to invasively measured LVFP; however, this varies widely with disease state. In heart failure with preserved ejection fraction, no single echocardiography-based metric offers a reliable estimate. In heart failure with reduced ejection fraction, mitral inflow-derived indices (E/e', E/A, E/Vp, and EDcT) have reasonable clinical applicability. While an integrated approach of several echocardiographic metrics provides the most promise for estimating LVFP reliably, such strategies need further validation in larger, patient-specific studies.

Left Ventricular Blood Flow Kinetic Energy Assessment by 4D Flow Cardiovascular Magnetic Resonance: A Systematic Review of the Clinical Relevance.

Background: There is an emerging body of evidence that supports the potential clinical value of left ventricular (LV) intracavity blood flow kinetic energy (KE) assessment using four-dimensional flow cardiovascular magnetic resonance imaging (4D flow CMR). The aim of this systematic review is to summarize studies evaluating LV intracavity blood flow KE quantification methods and its potential clinical significance. Methods: A systematic review search was carried out on Medline, Pubmed, EMBASE and CINAHL. Results: Of the 677 articles screened, 16 studies met eligibility. These included six (37%) studies on LV diastolic function, another six (37%) studies on heart failure or cardiomyopathies, three (19%) studies on ischemic heart disease or myocardial infarction and finally, one (6%) study on valvular heart disease, namely, mitral regurgitation. One of the main strengths identified by these studies is high reproducibility of LV blood flow KE hemodynamic assessment (mean coefficient of variability = 6 ± 2%) for the evaluation of LV diastolic function. Conclusions: The evidence gathered in this systematic review suggests that LV blood flow KE has great promise for LV hemodynamic assessment. Studies showed increased diagnostic confidence at no cost of additional time. Results were highly reproducible with low intraobserver variability.