Stephen Lyen

Comprehensive characterisation of hypertensive heart disease left ventricular phenotypes

Objective Myocardial intracellular/extracellular structure and aortic function were assessed among hypertensive left ventricular (LV) phenotypes using cardiovascular magnetic resonance (CMR). Methods An observational study from consecutive tertiary hypertension clinic patients referred for CMR (1.5 T) was performed. Four LV phenotypes were defined: (1) normal with normal indexed LV mass (LVM) and LVM to volume ratio (M/V), (2) concentric remodelling with normal LVM but elevated M/V, (3) concentric LV hypertrophy (LVH) with elevated LVM but normal indexed end-diastolic volume (EDV) or (4) eccentric LVH with elevated LVM and EDV. Extracellular volume fraction was measured using T1-mapping. Circumferential strain was calculated by voxel-tracking. Aortic distensibility was derived from high-resolution aortic cines and contemporaneous blood pressure measurements. Results 88 hypertensive patients (49±14 years, 57% men, systolic blood pressure (SBP): 167±30 mm Hg, diastolic blood pressure (DBP): 96±14 mm Hg) were compared with 29 age-matched/sex-matched controls (47±14 years, 59% men, SBP: 128±12 mm Hg, DBP: 79±10 mm Hg). LVH resulted from increased myocardial cell volume (eccentric LVH: 78±19 mL/m2 vs concentric LVH: 73±15 mL/m2 vs concentric remodelling: 55±9 mL/m2, p<0.05, respectively) and interstitial fibrosis (eccentric LVH: 33±10 mL/m2 vs concentric LVH: 30±10 mL/m2 vs concentricremodelling: 19±2 mL/m2, p<0.05, respectively). LVH had worst circumferential impairment (eccentric LVH: −12.8±4.6% vs concentric LVH: −15.5±3.1% vs concentric remodelling: –17.1±3.2%, p<0.05, respectively). Concentric remodelling was associated with reduced aortic distensibility, but not with large intracellular/interstitial expansion or myocardial dysfunction versus controls. Conclusions Myocardial interstitial fibrosis varies across hypertensive LV phenotypes with functional consequences. Eccentric LVH has the most fibrosis and systolic impairment. Concentric remodelling is only associated with abnormal aortic function. Understanding these differences may help tailor future antihypertensive treatments.

ECG strain pattern in hypertension is associated with myocardial cellular expansion and diffuse interstitial fibrosis: a multi-parametric cardiac magnetic resonance study

Aims In hypertension, the presence of left ventricular (LV) strain pattern on 12-lead electrocardiogram (ECG) carries adverse cardiovascular prognosis. The underlying mechanisms are poorly understood. We investigated whether hypertensive ECG strain is associated with myocardial interstitial fibrosis and impaired myocardial strain, assessed by multi-parametric cardiac magnetic resonance (CMR). Methods and results A total of 100 hypertensive patients [50 ± 14 years, male: 58%, office systolic blood pressure (SBP): 170 ± 30 mmHg, office diastolic blood pressure (DBP): 97 ± 14 mmHg) underwent ECG and 1.5T CMR and were compared with 25 normotensive controls (46 ± 14 years, 60% male, SBP: 124 ± 8 mmHg, DBP: 76 ± 7 mmHg). Native T1 and extracellular volume fraction (ECV) were calculated with the modified look-locker inversion-recovery sequence. Myocardial strain values were estimated with voxel-tracking software. ECG strain (n = 20) was associated with significantly higher indexed LV mass (LVM) (119 ± 32 vs. 80 ± 17 g/m2, P < 0.05) and ECV (30 ± 4 vs. 27 ± 3%, P < 0.05) compared with hypertensive subjects without ECG strain (n = 80). ECG strain subjects had significantly impaired circumferential strain compared with hypertensive subjects without ECG strain and controls (−15.2 ± 4.7 vs. −17.0 ± 3.3 vs. −17.3 ± 2.4%, P < 0.05, respectively). In subgroup analysis, comparing ECG strain subjects to hypertensive subjects with elevated LVM but no ECG strain, a significantly higher ECV (30 ± 4 vs. 28 ± 3%, P < 0.05) was still observed. Indexed LVM was the only variable independently associated with ECG strain in multivariate logistic regression analysis [odds ratio (95th confidence interval): 1.07 (1.02–1.12), P < 0.05). Conclusion In hypertension, ECG strain is a marker of advanced LVH associated with increased interstitial fibrosis and associated with significant myocardial circumferential strain impairment.

The effect of obesity on electrocardiographic detection of hypertensive left ventricular hypertrophy: recalibration against cardiac magnetic resonance.

Electrocardiograph (ECG) criteria for left ventricular hypertrophy (LVH) are a widely used clinical tool. We recalibrated six ECG criteria for LVH against gold-standard cardiac magnetic resonance (CMR) and assessed the impact of obesity. One hundred and fifty consecutive tertiary hypertension clinic referrals for CMR (1.5 T) were reviewed. Patients with cardiac pathology potentially confounding hypertensive LVH were excluded (n=22). The final sample size was 128 (age: 51.0±15.2 years, 48% male). LVH was defined by CMR. From a 12-lead ECG, Sokolow–Lyon voltage and product, Cornell voltage and product, Gubner–Ungerleidger voltage and Romhilt–Estes score were evaluated, blinded to the CMR. ECG diagnostic performance was calculated. LVH by CMR was present in 37% and obesity in 51%. Obesity significantly reduced ECG sensitivity, because of significant attenuation in mean ECG values for Cornell voltage (22.2±5.7 vs 26.4±9.4 mm, P<0.05), Cornell product (2540±942 vs 3023±1185 mm • ms, P<0.05) and for Gubner–Ungerleider voltage (18.2±7.1 vs 23.3±1.2 mm, P<0.05). Obesity also significantly reduced ECG specificity, because of significantly higher prevalence of LV remodeling (no LVH but increased mass-to-volume ratio) in obese subjects without LVH (36% vs 16%, P<0.05), which correlated with higher mean ECG LVH criteria values. Obesity-specific partition values were generated at fixed 95% specificity; Cornell voltage had highest sensitivity in non-obese (56%) and Sokolow–Lyon product in obese patients (24%). Obesity significantly lowers ECG sensitivity at detecting LVH, by attenuating ECG LVH values, and lowers ECG specificity through changes associated with LV remodeling. Our obesity-specific ECG partition values could improve the diagnostic performance in obese patients with hypertension.

Extra-cardiac findings in cardiovascular magnetic resonance: what the imaging cardiologist needs to know.

Cardiovascular magnetic resonance (CMR) is an established non-invasive technique to comprehensively assess cardiovascular structure and function in a variety of acquired and inherited cardiac conditions. A significant amount of the neck, thorax and upper abdomen are imaged at the time of routine clinical CMR, particularly in the initial multi-slice axial and coronal images. The discovery of unsuspected disease at the time of imaging has ethical, financial and medico-legal implications. Extra-cardiac findings at the time of CMR are common, can be important and can change clinical management. Certain patient groups undergoing CMR are at particular risk of important extra-cardiac findings as several of the cardiovascular risk factors for atherosclerosis are also risk factors for malignancy. Furthermore, the presence of certain extra-cardiac findings may contribute to the interpretation of the primary cardiac pathology as some cardiac conditions have multi-systemic extra-cardiac involvement. The aim of this review is to give an overview of the type of extra-cardiac findings that may become apparent on CMR, subdivided by anatomical location. We focus on normal variant anatomy that may mimic disease, common incidental extra-cardiac findings and important imaging signs that help distinguish sinister pathology from benign disease. We also aim to provide a framework to the approach and potential further diagnostic work-up of incidental extra-cardiac findings discovered at the time of CMR. However, it is beyond the scope of this review to discuss and determine the clinical significance of extracardiac findings at CMR.

Endovascular closure of thoracic aortic pseudoaneurysms: A combined device occlusion and coil embolization technique in patients unsuitable for surgery or stenting

Objectives Our aim was to retrospectively evaluate non-stent graft closure of ascending aortic pseudoaneurysms at our center over a 10-year period, and describe a combined device occlusion and coil embolization technique. Background Aortic pseudoaneurysms (APAs) are a rare complication post cardiothoracic surgery, but can have fatal complications. There is increasing use of percutaneous interventional techniques for occlusion of aortic pseudoaneurysms in patients who are considered unsuitable for surgery. Stent graft deployment may not be possible depending on the specific anatomy and pathology. Methods and Results Retrospective evaluation of the catheter laboratory database was performed at our center and anonymized data was obtained for patients who had nonstent endovascular treatment of APAs. Twelve patients were identified with a mean age of 63 ± 16 years. Seven patients had the combined occlusion and embolization technique, only 1/7 (14.3%) died from complications related to APAs. Five patients had occlusion device only, 3/5 (60%) died of complications related to their APA. The mean survival for the patients who had a combination procedure was 33.2±.22.6 months (range, 1 − 60 months), compared to 2.7 ± 2.6 months with device closure only (note 2 patients had short follow up of <3 months). Conclusions We evaluate non-stent graft percutaneous closure of APAs in a high-risk patient group and provide data on the use of a novel combined occlusion device and coil embolization technique. We feel this is a viable approach to APA closure in this population but this will require larger clinical studies in the future.

Optimising the imaging plane for right ventricular magnetic resonance volume analysis in adult patients referred for assessment of right ventricular structure and function

Our aim was to evaluate the reproducibility and accuracy of using short‐axis and axial (transaxial) plane for magnetic resonance imaging analysis in adult patients referred for assessment of right ventricular (RV) structure and function.

Phenotyping patterns of left ventricular remodeling and hypertrophy in systemic hypertension by cardiac magnetic resonance (CMR).

Methods Consecutive patients referred from our tertiary hypertension clinic, who underwent CMR at 1.5T, were included. Exclusion criteria included patients with clinical or CMR evidence of concomitant pathology (e.g. moderate-severe aortic stenosis) which may confound remodeling/hypertrophy pattern. Indexed LVM (iLVM), including papillary muscle mass by blood pool thresholding, indexed LV enddiastolic volume (iEDV) and ejection fraction (EF) were calculated using established CMR methods and normalized to body surface area. Values out-with the 95 th confidence intervals of established CMR normal reference values were considered abnormal. Mass : volume ratio (M/ V) >1.12 for men and >1.14 for women was defined as abnormal, in accordance with previous literature. The phenotypes of ventricular remodeling and hypertrophy were defined as either normal, concentric remodeling, asymmetric remodeling, concentric hypertrophy, asymmetric hypertrophy, eccentric hypertrophy or decompensation depending on the constellation of iLVM, iEDV, M/V, asymmetric thickness (>13mm and >1.5 fold opposing wall) and EF Results One hundred and twenty three (n=123) patients were analysed. The prevalence of different phenotypical responses were as follows: normal (42.3%), concentric remodeling (6.5%), asymmetric remodeling (5.7%), concentric hypertrophy (12.2%), asymmetric hypertrophy (17.9%) eccentric hypertrophy (8.9%) and decompensation (6.5%). The demographic and CMR characteristics of the different types of remodeling and hypertrophy are described in Figure 1. There was no predilection of remodeling/hypertrophic pattern according to hypertension type. 12.2% of our cohort had normal iLVM but demonstrated concentric/asymmetric remodeling. Subgroup analysis by remodeling (n=15) versus hypertrophy (n=22) revealed no significant difference in age (62±9.4 vs 55.1±12.4 years, p=0.0598), gender (% male 74.4% vs 68.2%, p=0.999), BMI (30.9±3.0 vs 30.1±4.9 kg/m 2 , p=0.5836), degree of hypertension (SBP 179.9±31.3 vs 176.8±24.7 mmHg, p=0.7407 and DBP 98.4±11.4 vs 95.7±14.8 mmHg, p=0.5557) or prevalence of potentially remodeling modifying medication (ACEi/ARB 80.0% vs 77.3%, p=0.999). Conclusions Varied CMR patterns of LV remodeling/hypertrophy occur in hypertensive patients with no predilection demonstrated in subgroup analysis. CMR-derived iLVM is increasingly used an end-point for clinical trials in hypertension. Our data suggest that patterns of LV remodeling/ hypertrophy should also be taken into account to avoid misclassifying patients with normal iLVM (but abnormal ventricles due to remodeling) together with patients with normal iLVM and truly normal ventricles.

A Novel Cause of Acute Coronary Syndrome Due to Dynamic Extrinsic Coronary Artery Compression by a Rib Exostosis: Multimodality Imaging Diagnosis

We report a case of acute coronary syndrome secondary to intermittent extrinsic compression of the left anterior descending coronary artery by inward-pointing rib exostosis in an 18-year-old woman during forceful repeated expiration in labour. The diagnosis was achieved using multimodality noninvasive cardiac imaging. In particular, we demonstrated the novel role of expiratory-phase cardiac computed tomography in confirming the anatomical relationship of the bony exostosis to the left anterior descending coronary artery. The case reminds us the heart and mediastinum move dynamically, relative to the bony thorax, throughout the respiratory cycle, and that changes in cardiac physiology in pregnancy may become pathological.

Cardiovascular Manifestations and Complications of Loeys-Dietz Syndrome: CT and MR Imaging Findings

Loeys-Dietz syndrome (LDS) is a recently described genetic connective tissue disorder with a wide spectrum of multisystem involvement. LDS is characterized by rapidly progressive aortic and peripheral arterial aneurysmal disease. LDS and the other inherited aortopathies such as Marfan syndrome have overlapping phenotypic features. However, LDS is characterized by a more aggressive vascular course; patient morbidity and mortality occur at an early age, with complications developing at relatively smaller aortic dimensions. In addition, there is more diffuse arterial involvement in LDS, with a large proportion of patients developing aneurysms of the iliac, mesenteric, and intracranial arteries. Early diagnosis and careful follow-up are essential for ensuring timely intervention in patients with arterial disease. Cross-sectional angiography has an important role in the baseline assessment, follow-up, and evaluation of acute complications of LDS, the thresholds and considerations of which differ from those of other inherited aortopathies. In this article, LDS is compared with other genetic vascular connective tissue disorders. In addition, the genetic, histopathologic, and cardiovascular manifestations of this disease process are reviewed, with a focus on computed tomographic and magnetic resonance imaging findings. Online DICOM image stacks and supplemental material are available for this article. ©RSNA, 2018.

22 Intra-ventricular myocardial deformation strain analysis in healthy volunteers: regional variation and implications for regional myocardial disease processes

Ejection fraction (EF) is a traditional marker of systolic function. However, it may not detect early, subtle cardiac disease with regional predilection. The aim of this study was to define regional intra-ventricular variation in myocardial strain in a cohort of healthy volunteers using Tissue-tracking cardiac magnetic resonance (CMR). Methods Healthy volunteers were recruited (n = 94, age range 20–79 years, 54% male). CMR at 1.5T was performed. Tissue-tracking software (CVI42, Circle Cardiovascular Imaging Inc.) estimated myocardial strain from the long-axis and the short-axis steady-state free precession (SSFP) cine images (Figure 1). The entire cohort was analysed by two independent readers. Inter-observer variability was also assessed. Myocardial segments were defined in accordance to the American Heart Association 16-segment model. Regional variations in circumferential and radial strain between basal, mid-cavity and apical segments as well as between left ventricle walls were assessed. Statistical analysis was performed using paired t test (p < 0.05). Results Inter-observer reproducibility analyses were excellent for mid-cavity and apical radial and circumferential strain values. On the other hand, reproducibility was not as good for basal segments for both deformation directions. Regional variations in strain (Table 1) revealed a statistically significant increase in deformation of the apical segments compared to the basal and mid-cavity ones for both radial and circumferential strain. Analysis of the different LV walls deformations indicated lowest values in the septum in all subjects, as well as across all age and gender subgroups. Conclusion This is the first study to demonstrate that there is a positive gradient toward the apex in both circumferential and radial strain using CMR-derived myocardial strain analysis. Furthermore, we also showed that the interventricular septum is the segment with lowest deformation values. These findings are important, as a comprehensive understanding of normal intra-ventricular regional variation is needed before this new tool can be implemented in routine clinical practice. Abstract 22 Table 1 Regional strain values Strain% Subgroup Basal Mid-cavity Apical P-value * Septal Lateral Anterior Inferior P-value ** Circumferential Gender Male (n = 51) −19 ± 2 −20 ± 2 −24 ± 2 <0.001 −16 ± 2 −24 ± 3 −22 ± 3 −22 ± 2 <0.001 Female (n = 43) −20 ± 2 −21 ± 3 −24 ± 3 <0.001 −17 ± 3 −24 ± 3 −23 ± 3 −22 ± 2 <0.001 Age (years) 20–39 (n = 28) −19 ± 2 −19 ± 2 −23 ± 3 <0.001 −15 ± 3 −23 ± 3 −22 ± 3 −21 ± 2 <0.001 40–59 (n = 35) −19 ± 2 −20 ± 2 −24 ± 2 <0.001 −16 ± 3 −24 ± 2 −22 ± 3 −22 ± 2 <0.001 60–79 (n = 31) −20 ± 2 −22 ± 2 −25 ± 3 <0.001 −17 ± 2 −26 ± 2 −24 ± 2 −23 ± 2 <0.001 Radial Gender Male (n = 51) 39 ± 6 37 ± 7 51 ± 9 <0.001 28 ± 6 52 ± 11 46 ± 9 44 ± 8 <0.001 Female (n = 43) 43 ± 8 39 ± 9 52 ± 11 <0.001 30 ± 8 52 ± 11 48 ± 11 45 ± 8 <0.001 Age (years) 20–39 (n = 28) 39 ± 7 34 ± 7 48 ± 10 <0.001 27 ± 7 47 ± 9 45 ± 10 42 ± 6 <0.001 40–59 (n = 35) 40 ± 6 37 ± 6 52 ± 10 <0.001 28 ± 8 50 ± 9 44 ± 10 42 ± 9 <0.001 60–79 (n = 31) 44 ± 9 43 ± 9 55 ± 11 <0.001 32 ± 5 60 ± 11 51 ± 9 49 ± 8 <0.001 * p-values between basal and apical ** p-values between septal and all the other walls Abstract 22 Figure 1 Definition of longitudinal, circumferential and radial myocardial strain, calculated by SSFP long-axis and short-axis cine images