4D Flow Cardiac MR in Primary Mitral Regurgitation.

BACKGROUND: Four-dimensional-flow cardiac MR (4DF-MR) offers advantages in primary mitral regurgitation. The relationship between 4DF-MR-derived mitral regurgitant volume (MR-Rvol) and the post-operative left ventricular (LV) reverse remodeling has not yet been established. PURPOSE: To ascertain if the 4DF-MR-derived MR-Rvol correlates with the LV reverse remodeling in primary mitral regurgitation. STUDY TYPE: Prospective, single-center, two arm, interventional vs. nonintervention observational study. POPULATION: Forty-four patients (male N = 30; median age 68 [59-75]) with at least moderate primary mitral regurgitation; either awaiting mitral valve surgery (repair [MVr], replacement [MVR]) or undergoing "watchful waiting" (WW). FIELD STRENGTH/SEQUENCE: 5 T/Balanced steady-state free precession (bSSFP) sequence/Phase contrast imaging/Multishot echo-planar imaging pulse sequence (five shots). ASSESSMENT: Patients underwent transthoracic echocardiography (TTE), phase-contrast MR (PMRI), 4DF-MR and 6-minute walk test (6MWT) at baseline, and a follow-up PMRI and 6MWT at 6 months. MR-Rvol was quantified by PMRI, 4DF-MR, and TTE by one observer. The pre-operative MR-Rvol was correlated with the post-operative decrease in the LV end-diastolic volume index (LVEDVi). STATISTICAL TESTS: Included Student t-test/Mann-Whitney test/Fisher's exact test, Bland-Altman plots, linear regression analysis and receiver operating characteristic curves. Statistical significance was defined as P < 0.05. RESULTS: While Bland-Altman plots demonstrated similar bias between all the modalities, the limits of agreement were narrower between 4DF-MR and PMRI (bias 15; limits of agreement -36 mL to 65 mL), than between 4DF-MR and TTE (bias -8; limits of agreement -106 mL to 90 mL) and PMRI and TTE (bias -23; limits of agreement -105 mL to 59 mL). Linear regression analysis demonstrated a significant association between the MR-Rvol and the post-operative decrease in the LVEDVi, when the MR-Rvol was quantified by PMRI and 4DF-MR, but not by TTE (P = 0.73). 4DF-MR demonstrated the best diagnostic performance for reduction in the post-operative LVEDVi with the largest area under the curve (4DF-MR 0.83; vs. PMRI 0.78; and TTE 0.51; P = 0.89). DATA CONCLUSION: This study demonstrates the potential clinical utility of 4DF-MR in the assessment of primary mitral regurgitation. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 5.

Aortic stenosis assessment from the 3-chamber cine: Ratio of balanced steady-state-free-precession (bSSFP) blood signal between the aorta and left ventricle predicts severity.

BACKGROUND: Cardiovascular magnetic resonance (CMR) imaging is an important tool for evaluating the severity of aortic stenosis (AS), co-existing aortic disease, and concurrent myocardial abnormalities. Acquiring this additional information requires protocol adaptations and additional scanner time, but is not necessary for the majority of patients who do not have AS. We observed that the relative signal intensity of blood in the ascending aorta on a balanced steady state free precession (bSSFP) 3-chamber cine was often reduced in those with significant aortic stenosis. We investigated whether this effect could be quantified and used to predict AS severity in comparison to existing gold-standard measurements. METHODS: Multi-centre, multi-vendor retrospective analysis of patients with AS undergoing CMR and transthoracic echocardiography (TTE). Blood signal intensity was measured in a ∼1 cm2 region of interest (ROI) in the aorta and left ventricle (LV) in the 3-chamber bSSFP cine. Because signal intensity varied across patients and scanner vendors, a ratio of the mean signal intensity in the aorta ROI to the LV ROI (Ao:LV) was used. This ratio was compared using Pearson correlations against TTE parameters of AS severity: aortic valve peak velocity, mean pressure gradient and the dimensionless index. The study also assessed whether field strength (1.5 T vs. 3 T) and patient characteristics (presence of bicuspid aortic valves (BAV), dilated aortic root and low flow states) altered this signal relationship. RESULTS: 314 patients (median age 69 [IQR 57-77], 64% male) who had undergone both CMR and TTE were studied; 84 had severe AS, 78 had moderate AS, 66 had mild AS and 86 without AS were studied as a comparator group. The median time between CMR and TTE was 12 weeks (IQR 4-26). The Ao:LV ratio at 1.5 T strongly correlated with peak velocity (r = -0.796, p = 0.001), peak gradient (r = -0.772, p = 0.001) and dimensionless index (r = 0.743, p = 0.001). An Ao:LV ratio of < 0.86 was 84% sensitive and 82% specific for detecting AS of any severity and a ratio of 0.58 was 83% sensitive and 92% specific for severe AS. The ability of Ao:LV ratio to predict AS severity remained for patients with bicuspid aortic valves, dilated aortic root or low indexed stroke volume. The relationship between Ao:LV ratio and AS severity was weaker at 3 T. CONCLUSIONS: The Ao:LV ratio, derived from bSSFP 3-chamber cine images, shows a good correlation with existing measures of AS severity. It demonstrates utility at 1.5 T and offers an easily calculable metric that can be used at the time of scanning or automated to identify on an adaptive basis which patients benefit from dedicated imaging to assess which patients should have additional sequences to assess AS.

Association Between Type 2 Diabetes and Changes in Myocardial Structure, Contractile Function, Energetics, and Blood Flow Before and After Aortic Valve Replacement in Patients With Severe Aortic Stenosis.

BACKGROUND: Type 2 diabetes (T2D) is associated with an increased risk of left ventricular dysfunction after aortic valve replacement (AVR) in patients with severe aortic stenosis (AS). Persistent impairments in myocardial energetics and myocardial blood flow (MBF) may underpin this observation. Using phosphorus magnetic resonance spectroscopy and cardiovascular magnetic resonance, this study tested the hypothesis that patients with severe AS and T2D (AS-T2D) would have impaired myocardial energetics as reflected by the phosphocreatine to ATP ratio (PCr/ATP) and vasodilator stress MBF compared with patients with AS without T2D (AS-noT2D), and that these differences would persist after AVR. METHODS: Ninety-five patients with severe AS without coronary artery disease awaiting AVR (30 AS-T2D and 65 AS-noT2D) were recruited (mean, 71 years of age [95% CI, 69, 73]; 34 [37%] women). Thirty demographically matched healthy volunteers (HVs) and 30 patients with T2D without AS (T2D controls) were controls. One month before and 6 months after AVR, cardiac PCr/ATP, adenosine stress MBF, global longitudinal strain, NT-proBNP (N-terminal pro-B-type natriuretic peptide), and 6-minute walk distance were assessed in patients with AS. T2D controls underwent identical assessments at baseline and 6-month follow-up. HVs were assessed once and did not undergo 6-minute walk testing. RESULTS: Compared with HVs, patients with AS (AS-T2D and AS-noT2D combined) showed impairment in PCr/ATP (mean [95% CI]; HVs, 2.15 [1.89, 2.34]; AS, 1.66 [1.56, 1.75]; P<0.0001) and vasodilator stress MBF (HVs, 2.11 mL min g [1.89, 2.34]; AS, 1.54 mL min g [1.41, 1.66]; P<0.0001) before AVR. Before AVR, within the AS group, patients with AS-T2D had worse PCr/ATP (AS-noT2D, 1.74 [1.62, 1.86]; AS-T2D, 1.44 [1.32, 1.56]; P=0.002) and vasodilator stress MBF (AS-noT2D, 1.67 mL min g [1.5, 1.84]; AS-T2D, 1.25 mL min g [1.22, 1.38]; P=0.001) compared with patients with AS-noT2D. Before AVR, patients with AS-T2D also had worse PCr/ATP (AS-T2D, 1.44 [1.30, 1.60]; T2D controls, 1.66 [1.56, 1.75]; P=0.04) and vasodilator stress MBF (AS-T2D, 1.25 mL min g [1.10, 1.41]; T2D controls, 1.54 mL min g [1.41, 1.66]; P=0.001) compared with T2D controls at baseline. After AVR, PCr/ATP normalized in patients with AS-noT2D, whereas patients with AS-T2D showed no improvements (AS-noT2D, 2.11 [1.79, 2.43]; AS-T2D, 1.30 [1.07, 1.53]; P=0.0006). Vasodilator stress MBF improved in both AS groups after AVR, but this remained lower in patients with AS-T2D (AS-noT2D, 1.80 mL min g [1.59, 2.0]; AS-T2D, 1.48 mL min g [1.29, 1.66]; P=0.03). There were no longer differences in PCr/ATP (AS-T2D, 1.44 [1.30, 1.60]; T2D controls, 1.51 [1.34, 1.53]; P=0.12) or vasodilator stress MBF (AS-T2D, 1.48 mL min g [1.29, 1.66]; T2D controls, 1.60 mL min g [1.34, 1.86]; P=0.82) between patients with AS-T2D after AVR and T2D controls at follow-up. Whereas global longitudinal strain, 6-minute walk distance, and NT-proBNP all improved after AVR in patients with AS-noT2D, no improvement in these assessments was observed in patients with AS-T2D. CONCLUSIONS: Among patients with severe AS, those with T2D demonstrate persistent abnormalities in myocardial PCr/ATP, vasodilator stress MBF, and cardiac contractile function after AVR; AVR effectively normalizes myocardial PCr/ATP, vasodilator stress MBF, and cardiac contractile function in patients without T2D.

Coexistent Diabetes Is Associated With the Presence of Adverse Phenotypic Features in Patients With Hypertrophic Cardiomyopathy.

OBJECTIVE: Type 2 diabetes mellitus (T2DM) is associated with worsened clinical outcomes in hypertrophic cardiomyopathy (HCM) patients. We sought to investigate whether HCM patients with T2DM comorbidity exhibit adverse cardiac alterations in myocardial energetics, function, perfusion, or tissue characteristics. RESEARCH DESIGN AND METHODS: A total of 55 participants with concomitant HCM and T2DM (HCM-DM) (n = 20) or isolated HCM (n = 20) and healthy volunteers (HV) (n = 15) underwent 31P-MRS and cardiovascular MRI. The HCM groups were matched for HCM phenotype. RESULTS: Mean ± SD European Society of Cardiology sudden cardiac death risk scores were comparable between the HCM groups (HCM 2.2 ± 1.5%, HCM-DM 1.9 ± 1.2%; P = not significant), and sarcomeric mutations were equally common. HCM-DM patients had the highest median NT-proBNP levels (HV 42 ng/L [interquartile range 35-66], HCM 298 ng/L [157-837], HCM-DM 726 ng/L [213-8,695]; P < 0.0001). Left ventricular (LV) ejection fraction, mass, and wall thickness were similar between the HCM groups. HCM-DM patients displayed a greater degree of fibrosis burden with higher scar percentage and lower global longitudinal strain compared with HCM patients. PCr/ATP (the relative concentrations of phosphocreatine and ATP) was significantly lower in the HCM-DM group than in both HCM and HV (HV 2.17 ± 0.49, HCM 1.93 ± 0.38, HCM-DM 1.54 ± 0.27; P = 0.002). In a similar pattern, stress myocardial blood flow was significantly lower in the HCM-DM group than in both HCM and HV (HV 2.06 ± 0.42 mL/min/g, HCM 1.74 ± 0.44 mL/min/g, HCM-DM 1.39 ± 0.42 mL/min/g; P = 0.002). CONCLUSIONS: We show for the first time that HCM-DM patients display greater reductions in myocardial energetics, perfusion, and contractile function and higher myocardial scar burden and serum NT-proBNP levels compared with patients with isolated HCM despite similar LV mass and wall thickness and presence of sarcomeric mutations. These adverse phenotypic features may be important components of the adverse clinical manifestation attributable to a combined presence of HCM and T2DM.

Postoperative epidural analgesia in obese patients undergoing liver resection surgery.

AIM: To investigate the relation of body mass index (BMI) with postoperative pain scores and volume of local anaesthetic (LA) administered epidurally in patients undergoing liver resection surgery. METHODS: Retrospective data from 167 patients who had epidural analgesia (EA) for liver resection surgery were analysed: 123 with BMI < 30kgm-2 and 44 with BMI > 30kgm-2. RESULTS: Total volume of intraoperative bolus of epidural analgesia (EA) was not different between the BMI more than 30 kgm-2 and BMI less than 30 kgm-2 groups (p less 0.05). Mean rate of infusion (8.2±2.7 ml/h vs. 7.9±1.9 ml/h, p=0.0018), pain scores immediately after extubation of the trachea (0.91±0.9 vs. 0.55±0.7, p=0.017) and that before removal of epidural catheter (0.7±0.55 vs. 0.7±0.95, p=0.015) were higher in the BMI > 30kgm-2 group when compared with the BMI ≤ 30kgm-2 group. However, there was no significant difference between the numbers of segments blocked. CONCLUSION: The patients with BMI more than 30 kgm-2 undergoing liver resection experienced more postoperative pain on the day of surgery and before epidural catheter removal than patients with BMI less than 30 kgm-2, despite a higher rate of epidural infusion. Further studies are necessary to confirm these findings in order to determine adequate local anaesthetic dosing for thoracic epidural analgesia in obese patients.

Calcium salts bone regeneration scaffolds: a review article.

A growing array of synthetic bone regeneration scaffolds has been in use over the last century. These scaffolds aim to provide a three dimensional substrate for bone cells to populate on and to function appropriately. The majority of commercially-available scaffolds are based on calcium sulphate salts, calcium phosphate salts, or composites of the two. The mechanical and biological properties of these scaffolds are a result of the properties of the constituent materials and their ratio in the composite. This review addresses the mechanical and biological characteristics and provides an up-to-date summary of the clinical data available about the use of these calcium-based scaffolds. It will also assess the benefit of using stem cell technology along with this type of scaffolds. This article links between the basic science evidence and the clinical outcomes and details the commercially-available options.