Pediatric heterozygous familial hypercholesterolemia patients have locally increased aortic pulse wave velocity and wall thickness at the aortic root

Familial hypercholesterolemia (FH) is an autosomal dominant disorder that affects 1 in 250 people. Aortic stiffness, measured by pulse wave velocity (PWV), is an independent predictor for cardiovascular events. Young FH patients are a unique group with early vessel wall disease that may serve to elucidate the determinants of aortic stiffness. We hypothesized that young FH patients would have early changes in aortic stiffness compared to healthy, age- and sex-matched reference values. Thirty-three FH patients ( ≥ 7 years age; mean age 14.6 ± 3.3 years; 26/33 on statin therapy) underwent cardiac MRI. PWV was determined using propagation of flow waveform from aortic arch phase contrast images. Distensibility and aortic wall thickness (AWT) were measured at the ascending, proximal descending, and diaphragmatic aorta. Ventricular volumes and left ventricular (LV) myocardial mass were measured from 2D cine images. These parameters were compared to age- and sex-matched reference values. FH patients had significantly higher PWV (4.5 ± 0.8 vs. 3.5 ± 0.3 m/s; p < 0.001), aortic distensibility, and ascending aortic wall thickness (1.37 ± 0.18 vs. 1.30 ± 0.02 mm; p < 0.05) compared to reference. There was no difference in aortic area or descending aortic wall thickness between groups. Young FH patients had aortic changes with increased aortic pulse wave velocity in the setting of increased aortic distensibility, accompanied by increased thickness of the ascending aortic wall. Presence of these early findings in young patients despite the majority being on statin therapy support enhanced screening and aggressive treatment of familial hypercholesterolemia to prevent potential future cardiovascular events.

Creating three dimensional models of the right ventricular outflow tract: influence of contrast, sequence, operator, and threshold

The use of 3D printed models of the right ventricular outflow tract (RVOT) for surgical and interventional planning is growing and often requires image segmentation of cardiac magnetic resonance (CMR) images. Segmentation results may vary based on contrast, image sequence, signal threshold chosen by the operator, and manual post-processing. The purpose of this study was to determine potential biases and post-processing errors in image segmentation to enable informed decisions. Models of the RVOT and pulmonary arteries from twelve patients who had contrast enhanced CMR angiography with gadopentetate dimeglumine (GPD), gadofosveset trisodium (GFT), and a post-GFT inversion-recovery (IR) whole heart sequence were segmented, trimmed, and aligned by three operators. Geometric agreement and minimal RVOT diameters were compared between sequences and operators. To determine the contribution of threshold, interoperator variability was compared between models created by the same two operators using the same versus different thresholds. Geometric agreement by Dice between objects was high (intraoperator: 0.89-0.95; interoperator: 0.95-0.97), without differences between sequences. Minimal RVOT diameters differed on average by - 1.9 to - 1.3 mm (intraoperator) and by 0.4 to 1.4 mm (interoperator). The contribution of threshold to interoperator geometric agreement was not significant (same threshold: 0.96 ± 0.06, different threshold: 0.93 ± 0.05; p = 0.181), but minimal RVOT diameters were more variable with different versus constant thresholds (- 9.12% vs. 2.42%; p < 0.05). Thresholding does not significantly change interoperator variability for geometric agreement, but does for minimal RVOT diameter. Minimal RVOT diameters showed clinically relevant variation within and between operators.

Feasibility of 3D black-blood variable refocusing angle fast spin echo cardiovascular magnetic resonance for visualization of the whole heart and great vessels in congenital heart disease

BACKGROUND

Volumetric black-blood cardiovascular magnetic resonance (CMR) has been hampered by long scan times and flow sensitivity. The purpose of this study was to assess the feasibility of black-blood, electrocardiogram (ECG)-triggered and respiratory-navigated 3D fast spin echo (3D FSE) for the visualization of the whole heart and great vessels.

METHODS

The implemented 3D FSE technique used slice-selective excitation and non-selective refocusing pulses with variable flip angles to achieve constant echo signal for tissue with T1 (880 ms) and T2 (40 ms) similar to the vessel wall. Ten healthy subjects and 21 patients with congenital heart disease (CHD) underwent 3D FSE and conventional 3D balanced steady-state free precession (bSSFP). The sequences were compared in terms of ability to perform segmental assessment, local signal-to-noise ratio (SNRl) and local contrast-to-noise ratio (CNRl).

RESULTS

In both healthy subjects and patients with CHD, 3D FSE showed superior pulmonary vein but inferior coronary artery origin visualisation compared to 3D bSFFP. However, in patients with CHD the combination of 3D bSSFP and 3D FSE whole-heart imaging improves the success rate of cardiac morphological diagnosis to 100% compared to either technique in isolation (3D FSE, 23.8% success rate, 3D bSSFP, 5% success rate). In the healthy subjects SNRl for 3D bSSFP was greater than for 3D FSE (30.1 ± 7.3 vs 20.9 ± 5.3; P = 0.002) whereas the CNRl was comparable (17.3 ± 5.6 vs 17.4 ± 4.9; P = 0.91) between the two scans.

CONCLUSIONS

The feasibility of 3D FSE for whole-heart black-blood CMR imaging has been demonstrated. Due to their high success rate for segmental assessment, the combination of 3D bSSFP and 3D FSE may be an attractive alternative to gadolinium contrast enhanced morphological CMR in patients with CHD.

Correlation of Foot Bimalleolar Angle and Ultrasonography in Assessing the Severity of Club Foot in Neonates Treated by the Ponseti Method

Introduction: Correlation of Pirani score and foot bimalleolar (FBM) angle has been used in few studies but correlation of FBM angle with ultrasonography has never been evaluated so they are being correlated in assessing the severity of clubfoot in neonates treated by Ponseti method. Material and Methods: Thirty-two feet with congenital talipes equinovarus (CTEV) deformity in neonates were prospectively treated by the Ponseti method. FBM angle and ultrasound parameters were measured three times i.e. at the time of initial presentation, at four weeks of treatment and at completion of treatment. The feet were divided according to the Pirani score in groups: one (0-2.0), two (2.5-4) and three (4.5-6). Correlation between FBM angle and ultrasound parameters were evaluated using Pearson correlation/regression. Results: Correlation between FBM angle and ultrasound parameters were statistically significant (p-value < 0.05). Conclusion: Ultrasound has the potential to accurately depict the pathoanatomy in clubfoot. FBM angle and ultrasound are objective methods to assess the severity of clubfoot. FBM angle and ultrasonography correlated in severity of deformity and correction achieved along the course of treatment.

Dual-phase whole-heart imaging using image navigation in congenital heart disease

Background

Dual-phase 3-dimensional whole-heart acquisition allows simultaneous imaging during systole and diastole. Respiratory navigator gating and tracking of the diaphragm is used with limited accuracy. Prolonged scan time is common, and navigation often fails in patients with erratic breathing. Image-navigation (iNAV) tracks movement of the heart itself and is feasible in single phase whole heart imaging. To evaluate its diagnostic ability in congenital heart disease, we sought to apply iNAV to dual-phase sequencing.

Methods

Healthy volunteers and patients with congenital heart disease underwent dual-phase imaging using the conventional diaphragmatic-navigation (dNAV) and iNAV. Acquisition time was recorded and image quality assessed. Sharpness and length of the right coronary (RCA), left anterior descending (LAD), and circumflex (LCx) arteries were measured in both cardiac phases for both approaches. Qualitative and quantitative analyses were performed in a blinded and randomized fashion.

Results

In volunteers, there was no significant difference in vessel sharpness between approaches (p > 0.05). In patients, analysis showed equal vessel sharpness for LAD and RCA (p > 0.05). LCx sharpness was greater with dNAV (p < 0.05). Visualized length with iNAV was 0.5 ± 0.4 cm greater than that with dNAV for LCx in diastole (p < 0.05), 1.0 ± 0.3 cm greater than dNAV for LAD in diastole (p < 0.05), and 0.8 ± 0.7 cm greater than dNAV for RCA in systole (p < 0.05). Qualitative scores were similar between modalities (p = 0.71). Mean iNAV scan time was 5:18 ± 2:12 min shorter than mean dNAV scan time in volunteers (p = 0.0001) and 3:16 ± 1:12 min shorter in patients (p = 0.0001).

Conclusions

Image quality of iNAV and dNAV was similar with better distal vessel visualization with iNAV. iNAV acquisition time was significantly shorter. Complete cardiac diagnosis was achieved. Shortened acquisition time will improve clinical applicability and patient comfort.

Safety and effectiveness of antireflux surgery in obese patients

Introduction The incidence of gastro-oesophageal reflux disease and obesity has increased significantly in recent years. The number of antireflux procedures being carried out on people with a higher body mass index (BMI) has been rising. Evidence is conflicting for outcomes of antireflux surgery in obese patients in terms of its safety and efficacy. Given the contradictory reports, this meta-analysis was undertaken to establish the outcomes of antireflux surgery (ARS) in obese patients and its associated safety. Methods A systematic electronic search was conducted using the PubMed, MEDLINE®, Ovid®, Cochrane Library and Google Scholar™ databases to identify studies that analysed the effect of BMI on the outcomes of ARS. A meta-analysis was performed using the random effects model. The intraoperative and postoperative outcomes that were examined included operative time, conversion to an open procedure, mean length of hospital stay, recurrence of acid reflux requiring reoperation and wrap migration. Results A total of 3,772 patients were included in 13 studies. There was no significant difference in procedure conversion rate, recurrence of reflux requiring reoperation or wrap migration between obese and non-obese patients. However, both the mean operative time and mean length of stay were longer for obese patients. Conclusions ARS in obese patients with gastro-oesophageal reflux disease is safe and outcomes are comparable with those in patients with a BMI in the normal range. A high BMI should therefore not be a deterrent to considering ARS for appropriate patients.

Laparoscopy-assisted gastrectomy in the elderly: experience from a UK centre

BACKGROUND Gastric cancer has a high incidence in the elderly in the UK, with a significant number of patients aged 75 years or more. While surgery forms the mainstay of treatment, evidence pertaining to the management of gastric cancer in the Western population in this age group is scarce. METHODS We retrospectively reviewed the outcomes of laparoscopy-assisted total and distal gastrectomies at our centre from 2005 to 2015. Patients aged 70 years or above were included in the elderly group. RESULTS A total of 60 patients underwent laparoscopy-assisted gastrectomy over a 10-year period, with a predominance of male patients. There was no significant difference in the rate of overall surgical and non-surgical complications, in-hospital mortality, operation time and length of hospital stay, between the elderly and non-elderly groups. Univariate analysis, performed for risk factors relating to anastomotic leak and surgical complications, showed that age over 70 years and higher American Association of Anesthesiologists grades are associated with a higher, though not statistically significant, number of anastomotic leaks (P = 1.000 and P = 0.442, respectively) and surgical complications (P = 0.469 and P = 0.162, respectively). The recurrence rate within the first 3 years of surgery was significantly higher in the non-elderly group compared with the elderly group (Log Rank test, P = 0.002). There was no significant difference in survival between the two groups (Log Rank test, P = 0.619). CONCLUSIONS Laparoscopy-assisted gastrectomy is safe and feasible in an elderly population. There is a need for well-designed, prospective, randomised studies with quality of life data to inform our practice in future.

Timely Pulmonary Valve Replacement May Allow Preservation of Left Ventricular Circumferential Strain in Patients with Tetralogy of Fallot

INTRODUCTION

Patients with Tetralogy of Fallot (TOF) and pulmonary insufficiency and a dilated right ventricle (RV) may suffer from a reduction in left ventricular (LV) performance. It is not clear whether timely pulmonary valve replacement (PVR) preserves LV mechanics.

METHODS

Ten TOF patients who underwent PVR were identified from hospital records, and pre- and postoperative cardiac magnetic resonance images were post-processed with a semi-automatic tissue tracking software. LV circumferential strain, time to peak strain, and torsion were compared before and after PVR. A control group of 10 age-matched normal volunteers was assessed as a comparison.

RESULTS

LV circumferential strain did not change before vs. after PVR (basal -18.3 ± 3.7 vs. -20.5 ± 3%, p = 0.082; mid-ventricular -18.4 ± 3.6 vs. -19.1 ± 2%, p = 0.571; apical -22.7 ± 5.2 vs. -22.1 ± 4%; p = 0.703). There was also no difference seen between the baseline strain and normal controls (control basal -18.2 ± 3.3%, p = 0.937; mid -18 ± 3.2%, p = 0.798; apex -24.1 ± 5%, p = 0.552). LV torsion remained unchanged from baseline to post PVR [systolic 2.75 (1.23-9.51) °/cm vs. 2.3 ± 1.2°/cm, p = 0.285; maximum 5.5 ± 3.5°/cm vs. 2.34 (1.37-8.07) °/cm, p = 0.083]. There was no difference in time to measured peak LV circumferential strain before vs. after PVR (basal 0.44 ± 0.1 vs. 0.43 ± 0.05, p = 0.912; mid-ventricular 0.42 ± 0.08 vs. 0.38 ± 0.06, p = 0.186; apical 0.40 ± 0.08 vs. 0.40 ± 0.06, p = 0.995). At the same time, pulmonary regurgitation and RV end-diastolic and end-systolic volume indices decreased and LV end-diastolic volume increased after PVR. RV and LV ejection fractions remained constant.

CONCLUSION

PVR allows for favorable remodeling of both ventricular volumes for TOF patients with significant pulmonary regurgitation. In this cohort, LV myocardial functional parameters such as circumferential strain, time to peak strain, and LV torsion were normal at baseline and remain unchanged after PVR.

Improved high-resolution pediatric vascular cardiovascular magnetic resonance with gadofosveset-enhanced 3D respiratory navigated, inversion recovery prepared gradient echo readout imaging compared to 3D balanced steady-state free precession readout imaging

BACKGROUND

Improved delineation of vascular structures is a common indication for cardiovascular magnetic resonance (CMR) in children and requires high spatial resolution. Currently, pre-contrast 3D, respiratory navigated, T2-prepared, fat saturated imaging with a bSSFP readout (3D bSSFP) is commonly used; however, these images can be limited by blood pool inhomogeneity and exaggeration of metal artifact. We compared image quality of pediatric vasculature obtained using standard 3D bSSFP to 3D, respiratory navigated, inversion recovery prepared imaging with a gradient echo readout (3D IR GRE) performed after administration of gadofosveset trisodium (GT), a blood pool contrast agent.

METHODS

For both sequences, VCG triggering was used with acquisition during a quiescent period of the cardiac cycle. 3D bSSFP imaging was performed pre-contrast, and 3D IR GRE imaging was performed 5 min after GT administration. We devised a vascular imaging quality score (VIQS) with subscores for coronary arteries, pulmonary arteries and veins, blood pool homogeneity, and metal artifact. Scoring was performed on axial reconstructions of isotropic datasets by two independent readers and differences were adjudicated. Signal- and contrast-to-noise (SNR and CNR) calculations were performed on each dataset.

RESULTS

Thirty-five patients had both 3D bSSFP and 3D IR GRE imaging performed. 3D IR GRE imaging showed improved overall vascular imaging compared to 3D bSSFP when comparing all-patient VIQS scores (n = 35, median 14 (IQR 11-15), vs 6 (4-10), p < 0.0001), and when analyzing the subset of patients with intrathoracic metal (n = 17, 16 (14-17) vs. 5 (2-9), p < 0.0001). 3D IR GRE showed significantly improved VIQS subscores for imaging the RCA, pulmonary arteries, pulmonary veins, and blood pool homogeneity. In addition, 3D IR GRE imaging showed reduced variability in both all-patient and metal VIQS scores compared to 3D bSSFP (p < 0.05). SNR and CNR were higher with 3D IR GRE in the left ventricle and left atrium, but not the pulmonary arteries.

CONCLUSIONS

Respiratory navigated 3D IR GRE imaging after GT administration provides improved vascular CMR in pediatric patients compared to pre-contrast 3D bSSFP imaging, as well as improved imaging in patients with intrathoracic metal. It is an excellent alternative in this challenging patient population when high spatial resolution vascular imaging is needed.

Parietex™ Composite mesh versus DynaMesh®-IPOM for laparoscopic incisional and ventral hernia repair: a retrospective cohort study

INTRODUCTION Laparoscopic incisional and ventral hernia repair (LIVHR) is widely accepted and safe but the type of mesh used is still debated. We retrospectively compared postoperative outcomes with two different meshes commonly used in LIVHR. METHODS This is a retrospective study of patients who underwent incisional hernia repair between January 2008 and December 2010. Two meshes were used: Parietex™ Composite (Covidien, New Haven, CT, USA) and the DynaMesh®-IPOM (FEG Textiltechnik mbH, Aachen, Germany). The two groups were compared with respect to recurrence rates, incidence of seroma and intestinal obstruction. RESULTS Among the 88 patients who underwent LIVHR, 75 patients (85.2%) presented with primary incisional hernia, 10 (11.4%) presented with a first recurrence and 3 (3.4%) presented with a second recurrence. Median follow-up was 53.6 months (range 40-61 months). 12.9% of patients had recurrence in the Parietex™ Composite mesh group (n=62) in comparison to 3.8% in the DynaMesh®-IPOM mesh group (n=26; P=0.20). DynaMesh®-IPOM was associated with a significantly higher incidence of intestinal obstruction secondary to adhesions (11.5% vs. 0%, P=0.006) and lower incidence of seroma and haematoma formation compared to Parietex™ composite mesh group (0% vs. 6.4% of patients; P=0.185). CONCLUSIONS LIVHR is a safe and feasible technique. Dynamesh®-IPOM is associated with a significantly higher incidence of adhesion related bowel obstruction, albeit with a lower incidence of recurrence, seroma and haematoma formation compared with Parietex™ Composite mesh. However, there is a need for further well-designed, multicentre randomised controlled studies to investigate the use of these meshes.

A clinical combined gadobutrol bolus and slow infusion protocol enabling angiography, inversion recovery whole heart, and late gadolinium enhancement imaging in a single study

BACKGROUND

The use of gadolinium contrast agents in cardiovascular magnetic resonance is well-established and serves to improve both vascular imaging as well as enable late gadolinium enhancement (LGE) imaging for tissue characterization. Currently, gadofosveset trisodium, an intravascular contrast agent, combined with a three-dimensional inversion recovery balanced steady state free precession (3D IR bSSFP) sequence, is commonly used in pediatric cardiac imaging and yields excellent vascular imaging, but cannot be used for late gadolinium enhancement. Gadofosveset use remains limited in clinical practice, and manufacture was recently halted, thus an alternative is needed to allow 3D IR bSSFP and LGE in the same study.

METHODS

Here we propose a protocol to give a bolus of 0.1 mL/kg = 0.1 mmol/kg gadobutrol (GADAVIST/GADOVIST) for time-resolved magnetic resonance angiography (MRA). Subsequently, 0.1 mmol/kg is diluted up to 5 or 7.5 mL with saline and then loaded into intravenous tubing connected to the patient. A 0.5 mL short bolus is infused, then a slow infusion is given at 0.02 or 0.03 mL/s. Image navigated (iNAV) 3D IR bSSFP imaging is initiated 45-60 s after the initiation of the infusion, with a total image acquisition time of ~5 min. If necessary, LGE imaging using phase sensitive inversion recovery reconstruction (PSIR) is performed at 10 min after the infusion is initiated.

RESULTS

We have successfully performed the above protocol with good image quality on 10 patients with both time-resolved MRA and 3D IR bSSFP iNAV imaging. Our initial attempts to use pencil beam respiratory navigation failed due to signal labeling in the liver by the navigator. We have also performed 2D PSIR LGE successfully, with both LGE positive and LGE negative results.

CONCLUSION

A bolus of gadobutrol, followed later by a slow infusion, allows time-resolved MRA, 3D IR bSSFP using the iNAV navigation technique, and LGE imaging, all in a single study with a single contrast agent.

Day case laparoscopic cholecystectomy in patients with high BMI: Experience from a UK centre

INTRODUCTION

Symptomatic gall stones may require laparoscopic cholecystectomy (LC), which is one of the most commonly performed general surgical operations in the western world. Patients with a high body mass index (BMI) are at increased risk of having gall stones, and are often considered at high risk of surgical complications due to their increased BMI. We believe that day case surgery could nevertheless have significant benefits in terms of potential cost savings and patient satisfaction in this population. We therefore compared the outcomes of day case patients undergoing LC stratified by BMI, with a specific focus on the safety and success of the procedure in obese and morbidly obese groups.

METHODS

We reviewed a database of day case procedures performed between January 2004 and December 2012, including all patients with symptomatic gall stone disease who underwent LC. The patients were divided in four BMI groups: less than 25 kg/m(2), 25-29 kg/m(2), 30-39 kg/m(2) and 40 kg/m(2) or above.

RESULTS

The overall success rate for day case surgery was 78%. There were no significant differences in rates of intra-abdominal collection or readmission with increasing BMI. However, increasing BMI was associated with a significant increase in the rate of wound infection.

CONCLUSIONS

LC in patients with a high BMI is safe and can be performed effectively as a day case procedure.

Meta-analysis of closure of the fascial defect during laparoscopic incisional and ventral hernia repair

Background

Laparoscopic incisional and ventral hernia repair (LIVHR) is being used increasingly, with reported outcomes equivalent to those of open hernia repair. Closure of the fascial defect (CFD) is a technique that may reduce seroma formation and bulging after LIVHR. Non-closure of the fascial defect makes the repair of larger defects easier and reduces postoperative pain. The aim of this systematic review was to determine whether CFD affects the rate of adverse outcomes, such as recurrence, pseudo-recurrence, mesh eventration or bulging, and the rate of seroma formation.

Methods

A systematic search was performed of PubMed, Ovid, the Cochrane Library, Google Scholar and Scopus to identify RCTs that analysed CFD with regard to rates of adverse outcomes. A meta-analysis was done using fixed-effect methods. The primary outcome of interest was adverse events. Secondary outcomes were seroma, postoperative pain, mean hospital stay, mean duration of operation and surgical techniques employed.

Results

A total of 16 studies were identified involving 3638 patients, 2963 in the CFD group and 675 in the non-closure of facial defect group. Significantly fewer adverse events were noted following CFD than non-closure (4·9 per cent (79 of 1613) versus 22·3 per cent (114 of 511)), with a combined risk ratio (RR) of 0·25 (95 per cent c.i. 0·18 to 0·33; P &lt; 0·001). CFD resulted in a significantly lower rate of seroma (2·5 per cent (39 of 1546) versus 12·2 per cent (47 of 385)), with a combined RR of 0·37 (0·23 to 0·57; P &lt; 0·001), and shorter duration of hospital stay. No significant difference was noted in postoperative pain.

Conclusion

CFD during LIVHR reduces the rate of seroma formation and adverse hernia-site events.

Use of a semi-automated cardiac segmentation tool improves reproducibility and speed of segmentation of contaminated right heart magnetic resonance angiography

Three-dimensional printing has an increasing number of clinical applications in pediatric cardiology. Time required for dataset segmentation and conversion to stereolithography (STL) format remains a significant limitation. We investigated the impact of semi-automated cardiovascular-specific segmentation software on time and reproducibility of segmentation. Magnetic resonance angiograms (MRAs) of 19 patients undergoing intervention for right ventricular outflow lesions were segmented to demonstrate the right heart. STLs were created by two independent clinicians using semi-automated cardiovascular segmentation (SAS) and traditional manual segmentation (MS). Time was recorded and geometric STL disagreement was determined (0 % = no disagreement, 100 % = complete disagreement). MRA datasets were categorized as clean when only right heart structures were present in the MRA, or contaminated when left heart structures were also present and required removal. Eighteen (seven clean and 11 contaminated) cases were successfully segmented with both methods. Time to STL for clean datasets was faster with MS than SAS [median 209 s (IQR 192-252) vs. 296 s (272-317), p = 0.018] while contaminated datasets were faster with SAS [455 s (384-561) vs. 866 s (310-1429), p = 0.033]. Interobserver STL geometric disagreement was significantly lower using SAS than MS overall (0.70 ± 1.15 % vs. 1.31 ± 1.52 %, p = 0.030), and for the contaminated subset (0.81 ± 1.08 % vs. 1.75 ± 1.57 %, p = 0.036). Most geometric disagreement occurred at areas where left heart contamination was removed. Semi-automated segmentation was faster and more reproducible for contaminated datasets, while MS was faster but equally reproducible for clean datasets. Semi-automated segmentation methods are preferable for contaminated datasets and continued refinement of these tools should be supported.

A systematic review of image segmentation methodology, used in the additive manufacture of patient-specific 3D printed models of the cardiovascular system

Background

Shortcomings in existing methods of image segmentation preclude the widespread adoption of patient-specific 3D printing as a routine decision-making tool in the care of those with congenital heart disease. We sought to determine the range of cardiovascular segmentation methods and how long each of these methods takes.

Methods

A systematic review of literature was undertaken. Medical imaging modality, segmentation methods, segmentation time, segmentation descriptive quality (SDQ) and segmentation software were recorded.

Results

Totally 136 studies met the inclusion criteria (1 clinical trial; 80 journal articles; 55 conference, technical and case reports). The most frequently used image segmentation methods were brightness thresholding, region growing and manual editing, as supported by the most popular piece of proprietary software: Mimics (Materialise NV, Leuven, Belgium, 1992–2015). The use of bespoke software developed by individual authors was not uncommon. SDQ indicated that reporting of image segmentation methods was generally poor with only one in three accounts providing sufficient detail for their procedure to be reproduced.

Conclusions and implication of key findings

Predominantly anecdotal and case reporting precluded rigorous assessment of risk of bias and strength of evidence. This review finds a reliance on manual and semi-automated segmentation methods which demand a high level of expertise and a significant time commitment on the part of the operator. In light of the findings, we have made recommendations regarding reporting of 3D printing studies. We anticipate that these findings will encourage the development of advanced image segmentation methods.

Dystrophin genotype-cardiac phenotype correlations in Duchenne and Becker muscular dystrophies using cardiac magnetic resonance imaging

Duchenne and Becker muscular dystrophies are caused by mutations in dystrophin. Cardiac manifestations vary broadly, making prognosis difficult. Current dystrophin genotype-cardiac phenotype correlations are limited. For skeletal muscle, the reading-frame rule suggests in-frame mutations tend to yield milder phenotypes. We performed dystrophin genotype-cardiac phenotype correlations using a protein-effect model and cardiac magnetic resonance imaging. A translational model was applied to patient-specific deletion, indel, and nonsense mutations to predict exons and protein domains present within truncated dystrophin protein. Patients were dichotomized into predicted present and predicted absent groups for exons and protein domains of interest. Development of myocardial fibrosis (represented by late gadolinium enhancement [LGE]) and depressed left ventricular ejection fraction (LVEF) were compared. Patients (n = 274) with predicted present cysteine-rich domain (CRD), C-terminal domain (CTD), and both the N-terminal actin-binding and cysteine-rich domains (ABD1 + CRD) had a decreased risk of LGE and trended toward greater freedom from LGE. Patients with predicted present CTD (exactly the same as those with in-frame mutations) and ABD1 + CRD trended toward decreased risk of and greater freedom from depressed LVEF. In conclusion, genotypes previously implicated in altering the dystrophinopathic cardiac phenotype were not significantly related to LGE and depressed LVEF. Patients with predicted present CRD, CTD/in-frame mutations, and ABD1 + CRD trended toward milder cardiac phenotypes, suggesting that the reading-frame rule may be applicable to the cardiac phenotype. Genotype-phenotype correlations may help predict the cardiac phenotype for dystrophinopathic patients and guide future therapies.

Myocardial fibrosis burden predicts left ventricular ejection fraction and is associated with age and steroid treatment duration in duchenne muscular dystrophy

Background

Patients with Duchenne muscular dystrophy exhibit progressive cardiac and skeletal muscle dysfunction. Based on prior data, cardiac dysfunction in Duchenne muscular dystrophy patients may be influenced by myocardial fibrosis and steroid therapy. We examined the longitudinal relationship of myocardial fibrosis and ventricular dysfunction using cardiac magnetic resonance in a large Duchenne muscular dystrophy cohort.

Methods and Results

We reviewed 465 serial cardiac magnetic resonance studies (98 Duchenne muscular dystrophy patients with ≥4 cardiac magnetic resonance studies) for left ventricular ejection fraction (LVEF) and presence of late gadolinium enhancement (LGE), a marker for myocardial fibrosis. LVEF was modeled by examining LGE status, myocardial fibrosis burden (as assessed by the number of LGE‐positive left ventricular segments), patient age, and steroid treatment duration. An age‐only model demonstrated that LVEF declined 0.58±0.10% per year. In patients with both LGE‐negative and LGE‐positive studies (n=51), LVEF did not decline significantly over time if LGE was absent but declined 2.2±0.31% per year when LGE was present. Univariate modeling showed significant associations between LVEF and steroid treatment duration, presence of LGE, and number of LGE‐positive left ventricular segments; multivariate modeling showed that LVEF declined by 0.93±0.09% for each LGE‐positive left ventricular segment, whereas age and steroid treatment duration were not significant. The number of LGE‐positive left ventricular segments increased with age, and longer steroid treatment duration was associated with lower age‐related increases.

Conclusion

Progressive myocardial fibrosis, as detected by LGE, was strongly correlated with the LVEF decline in Duchenne muscular dystrophy patients. Longer steroid treatment duration was associated with a lower age‐related increase in myocardial fibrosis burden.