Confronting heterogeneity in cryogenic electron microscopy data: Innovative strategies and future perspectives with data-driven methods

The surge in the influx of data from cryogenic electron microscopy (cryo-EM) experiments has intensified the demand for robust algorithms capable of autonomously managing structurally heterogeneous datasets. This presents a wealth of exciting opportunities from a data science viewpoint, inspiring the development of numerous innovative, application-specific methods, many of which leverage contemporary data-driven techniques. However, addressing the challenges posed by heterogeneous datasets remains a paramount yet unresolved issue in the field. Here, we explore the subtleties of this challenge and the array of strategies devised to confront it. We pinpoint the shortcomings of existing methodologies and deliberate on prospective avenues for improvement. Specifically, our discussion focuses on strategies to mitigate model overfitting and manage data noise, as well as the effects of constraints, priors, and invariances on the optimization process.

Comparing machine learning algorithms for non-invasive detection and classification of failure in piezoresistive bone cement via electrical impedance tomography

At an estimated cost of $8 billion annually in the United States, revision surgeries to total joint replacements represent a substantial financial burden to the health care system and a tremendous mental and physical burden on patients and their caretakers. Fixation failures, such as implant loosening, wear, and mechanical instability of the poly(methyl methacrylate) (PMMA) cement, which bonds the implant to the bone, are the main causes of long-term implant failure. Early and accurate diagnosis of cement failure is critical for developing novel therapeutic strategies and reducing the high risk of a misjudged revision. Unfortunately, prevailing imaging modalities, notably plain radiographs, struggle to detect the precursors of implant failure and are often interpreted incorrectly. Our prior work has shown that the modification of PMMA bone cement with low concentrations of conductive fillers makes it piezoresistive and therefore self-sensing. When combined with a conductivity imaging modality such as electrical impedance tomography (EIT), it is possible to monitor load transfer across the PMMA using cost-effective, physiologically benign, non-contact, and real-time electrical measurements. Despite the ability of EIT for monitoring load transfer across self-sensing PMMA bone cement, it is unable to accurately characterize failure mechanisms. Overcoming this challenge is critical to the success of this technology in practice. Therefore, we herein expand upon our previous results by integrating machine learning techniques with EIT for cement condition characterization with the goal of establishing the feasibility of even off-the-shelf machine learning algorithms to address this important problem. We survey a wide variety of different machine learning algorithms for application to this problem, including neural networks on voltage readings of an EIT phantom for tracking the spatial position of a sample, specifying defect orientation within a sample, and classifying defect types, including cracks and delaminations. In addition, we explore the utilization of principal component analysis (PCA) for pre-treating impedance signals in each of these problems. Within the tested algorithms, our results show clear advantages of neural networks, support vector machines, and K-nearest neighbor algorithms for interpreting EIT signals. We also show that PCA is an effective addition to machine learning. These preliminary results demonstrate that the combination of smart materials, EIT, and machine learning may be a powerful instrumentation tool for diagnosing the origin and evolution of mechanical failure in joint replacements.

Cryo-EM structure of the complete inner kinetochore of the budding yeast point centromere

The point centromere of budding yeast specifies assembly of the large kinetochore complex to mediate chromatid segregation. Kinetochores comprise the centromere-associated inner kinetochore (CCAN) complex and the microtubule-binding outer kinetochore KNL1-MIS12-NDC80 (KMN) network. The budding yeast inner kinetochore also contains the DNA binding centromere-binding factor 1 (CBF1) and CBF3 complexes. We determined the cryo-electron microscopy structure of the yeast inner kinetochore assembled onto the centromere-specific centromere protein A nucleosomes (CENP-ANuc). This revealed a central CENP-ANuc with extensively unwrapped DNA ends. These free DNA duplexes bind two CCAN protomers, one of which entraps DNA topologically, positioned on the centromere DNA element I (CDEI) motif by CBF1. The two CCAN protomers are linked through CBF3 forming an arch-like configuration. With a structural mechanism for how CENP-ANuc can also be linked to KMN involving only CENP-QU, we present a model for inner kinetochore assembly onto a point centromere and how it organizes the outer kinetochore for chromosome attachment to the mitotic spindle.

Simple and safe digitoxin dosing in heart failure based on data from the DIGIT-HF trial

BACKGROUND

The present study aimed to develop a simple dosing score when starting the cardiac glycoside digitoxin in heart failure with reduced ejection fraction (HFrEF) employing first data from the randomized, double-blinded DIGIT-HF trial.

METHODS AND RESULTS

In DIGIT-HF, digitoxin was started with a dose of 0.07 mg once daily (o.d.) in all patients. For score derivation, 317 patients were analyzed who had been randomized to digitoxin. In these patients, after scheduled determination of serum levels at study week 6, the digitoxin dose had remained unchanged or had been reduced to 0.05 mg o.d. (97% of patients) to achieve serum concentrations within a predefined range (10.5-23.6 nmol/l). In logistic regression analyses, sex, age, body mass index (BMI), and estimated glomerular filtration rate (eGFR) were associated with need for dose reduction and, therefore, selected for further developing the dosing score. Optimal cut-points were derived from ROC curve analyses. Finally, female sex, age ≥ 75 years, eGFR < 50 ml/min/1.73 m², and BMI < 27 kg/m² each were assigned one point for the digitoxin dosing score. A score of ≥ 1 indicated the need for dose reduction with sensitivity/specificity of 81.6%/49.7%, respectively. Accuracy was confirmed in a validation data set including 64 patients randomized to digitoxin yielding sensitivity/specificity of 87.5%/37.5%, respectively.

CONCLUSION

In patients with HFrEF, treatment with digitoxin should be started at 0.05 mg o.d. in subjects with either female sex, eGFR < 50 ml/min/1.73m², BMI < 27 kg/m², or age ≥ 75 years. In any other patient, digitoxin may be safely started at 0.07 mg o.d.

Mechanical modifications of soft actuators for the use as a dynamic iris implant

Aniridia is a condition characterized by defects or absence of the iris. Since the eyes are a central point of attention in the human face, these deformities are often covered with cosmetic implants. However, patients suffer from the static pupil diameter of these implants, resulting in high light sensitivity or inadequate night vision. Therefore, we present a functional iris implant based on dielectric elastomer actuators. These electric drives are characterized by a silent and continuous adaptation as well as a small construction volume and a low heat emission. Since they normally exhibit in-plane uniaxial motion, this displacement must be focused to operate similarly to the iris sphincter. Therefore, we investigated possible mechanical modifications of the setups to generate a directional motion. The results of the study are presented and discussed.Clinical Relevance- The proposed system design enables the functional treatment of aniridia and other accidental iris defects. In addition, the system serves as a basis for later developments of e.g. functional lenses that allow focus adjustment.

Influence of rosuvastatin treatment on cerebral inflammation and nitro-oxidative stress in experimental lung injury in pigs

BACKGROUND

Many patients with acute respiratory distress syndrome (ARDS) suffer from cognitive impairment after hospital discharge. Different mechanisms have been implicated as potential causes for this impairment, inter alia cerebral inflammation. A class of drugs with antioxidant and anti-inflammatory properties are β-HMG-CoA-reductase inhibitors ("statins"). We hypothesized that treatment with rosuvastatin attenuates cerebral cytokine mRNA expression and nitro-oxidative stress in an animal model of acute lung injury.

METHODS

After approval of the institutional and state animal care committee, we performed this prospective randomized controlled animal study in accordance with the international guidelines for the care and use of laboratory animals. Thirty-two healthy male pigs were randomized to one of four groups: lung injury by central venous injection of oleic acid (n = 8), statin treatment before and directly after lung injury (n = 8), statin treatment after lung injury (n = 8), or ventilation-only controls (n = 8). About 18 h after lung injury and standardized treatment, the animals were euthanised, and the brains and lungs were collected for further examinations. We determined histologic lung injury and cerebral and pulmonal cytokine and 3-nitrotyrosine production.

RESULTS

We found a significant increase in hippocampal IL-6 mRNA after lung injury (p < 0.05). Treatment with rosuvastatin before and after induction of lung injury led to a significant reduction of hippocampal IL-6 mRNA (p < 0.05). Cerebral 3-nitrotyrosine was significantly higher in lung-injured animals compared with all other groups (p < 0.05 vs. animals treated with rosuvastatin after lung injury induction; p < 0.001 vs. all other groups). 3-Nitrotyrosine was also increased in the lungs of the lung-injured pigs compared to all other groups (p < 0.05 each).

CONCLUSIONS

Our findings highlight cerebral cytokine production and nitro-oxidative stress within the first day after induction of lung injury. The treatment with rosuvastatin reduced IL-6 mRNA and 3-nitrotyrosine concentration in the brains of the animals. In earlier trials, statin treatment did not reduce mortality in ARDS patients but seemed to improve quality of life in ARDS survivors. Whether this is attributable to better cognitive function because of reduced nitro-oxidative stress and inflammation remains to be elucidated.

Case report: Flattening of the tectal plate in obstructive hydrocephalus with auto-ventriculostomy

BACKGROUND

Obstructive hydrocephalus in adulthood can be caused by stenosis in the aqueductal area. Chronic changes lead to a dilatation of the lateral ventricles and ballooning of infratentorial recesses. In rare cases a rupture of the floor of the third ventricle (so-called spontaneous ventriculostomy) has been described in the literature.Case presentation: We present two cases of chronic obstructive hydrocephalus due to aqueductal stenosis in adult patients. Magnetic resonance imaging included phase-contrast-imaging and revealed significant flow through the floor of the third ventricle in keeping with spontaneous ventriculostomy. In addition to other typical changes associated with chronic hydrocephalus, a distinct flattening of the tectal plate could be identified in one case.

CONCLUSION

We present two cases of spontaneous ventriculostomy in patients with chronic hydrocephalus. To our knowledge, flattening of the tectal plate has not yet been described in the literature and may be caused by continuous cerebrospinal fluid-pulsation.

POS1150 ANATOMICAL LOCATIONS AND CORRELATES OF CALCIUM PYROPHOSPHATE CRYSTAL DEPOSITS OF THE SPINE – PATHOLOGIC EXAMINATION OF 77 SURGICAL CASES

Background:

Spinal involvement in calcium pyrophosphate deposition disease (CPPD) is thought to be a rare occurrence and is seen infrequently as crowned dens syndrome. Furthermore, data on anatomical locations and correlates of calcium pyrophosphate (CPP) deposits in spinal CPPD are scarce.

Objectives:

To describe the anatomical locations and correlates of pathologically confirmed CPPD of the spine.

Methods:

Consecutive patients with spinal CPPD were identified via retrospective chart review of individuals who underwent spine surgery for intractable chronic neck or back pain at Massachusetts General Hospital between 2009 and 2014. These deposits and surrounding anatomical structures were surgically resected and confirmed to have calcium pyrophosphate deposition upon pathologic review. We reviewed musculoskeletal imaging (CT, MRI, XR) and laboratory data from these pathologically confirmed cases.

Results:

From April 2009 to August 2014, we identified 77 individuals with pathologically confirmed CPPD of the spine. The mean age was 68 years; 41 (53%) were female; mean BMI was 28.7. Calcium pyrophosphate (CPP) was grossly identified intraoperatively by the surgeon in 38 cases (50%), typically as “chalky white deposits” (Figure 1). CPP deposits were seen most frequently in the ligamentum flavum (23%) and intervertebral disc (23%), followed by other less common locations (Table 1). Imaging findings in the soft tissue or intervertebral disc suggestive of CPPD were found in 5 cases (6%), whereas findings of spinal canal narrowing, facet arthropathy, or ligamentum flavum thickening were eventually correlative with CPP deposits in pathologic specimens. Only 7 (9%) experienced a prior episode of acute CPP arthritis (pseudogout). Chondrocalcinosis on x-ray was seen in 26 cases (34%), most commonly in the wrist and/or knees. Osteoarthritis was present in all spinal imaging, and 65% had comorbid scoliosis. Laboratory abnormalities associated with secondary causes of CPPD (hypercalcemia, hypomagnesemia, hyperparathyroidism) were not seen with spinal CPPD.

Conclusion:

Spinal CPPD may occur more frequently than previously perceived. The ligamentum flavum and intervertebral discs were common anatomical locations for spinal CPPD. Advanced imaging of the spine showed low sensitivity for detecting spinal CPPD. Only a small minority had typical peripheral joint involvement or imaging with peripheral joint chondrocalcinosis. Thus, without pathologic confirmation, the vast majority of cases would remain unidentified. These findings call for the need to seek pathologic confirmation to determine the robust epidemiology and also raise the potential role for preoperative CPPD treatment.

Table 1.

Spinal Anatomic Locations of Pathologically Confirmed CPPD

Spinal Anatomic LocationNo. of Sites (%)*ligamentum flavum29 (23)Intervetebral Disc28 (23)Other Location19 (15)Posterior Elements18 (15)Facet14 (11)Synovium8 (6)Interspinous Ligament3 (2)Subarticular/Lateral Recess2 (2)Fibrocartilaginous Tissue1 (1)Inner Spine1 (1)Other Ligament1 (1)

*Some patients had more than one anatomic location where CPP was isolated

Figure 1.

Gross visualization of calcium pyrophosphate deposition (black arrow)

Disclosure of Interests:

Jonathan Dau: None declared, Gary Ho: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, Vaxart, Grant/research support from: Ironwood, Horizon, Joseph Schwab: None declared, Minna Kohler Speakers bureau: Eli Lily, Consultant of: Novartis.

Males Have Higher Rates of Peri-operative Mortality Following Surgery for Osteoporotic Vertebral Compression Fracture

In this study, we evaluated the association between sex and the incidence of postoperative mortality in the peri-operative period following surgical intervention for OVCF. We found no statistical association between surgical complications and patient sex. However, males exhibited higher rates of mortality and 30-day readmissions relative to females.

INTRODUCTION

Osteoporotic vertebral compression fractures (OVCF) contribute substantially to the financial burden of the US healthcare system. As the size of the elderly population grows, the number of fractures attributed to osteoporosis is expected to increase. Studies have shown that osteoporotic patients are at an increased risk for medical and surgical complications. The purpose of this study was to evaluate the association between sex and the incidence of postoperative mortality in the peri-operative period following surgical intervention for OVCF.

METHODS

A retrospective analysis of the American College of Surgeons National Surgery Quality Improvement Project (ACS-NSQIP) database from 2007 to 2014 identified 1979 patients. Patients were grouped as male or female. Mortality within 30 days of surgery due to any cause, incidence of surgical complications, and 30-day readmission rates following surgery were tabulated. A multivariate logistic regression analysis was conducted to calculate odds ratios (OR) with corresponding p values and 95% confidence intervals.

RESULTS

In total, 1979 patients met inclusion and exclusion criteria. Mortality within the 30 days following surgery for OVCF was statistically greater in men than in women (OR = 1.58; p = 0.050). The 30-day readmission rate was also statistically higher in men (OR = 1.41; p = 0.017). Neither minor (OR = 0.90; p = 0.560) nor major (OR = 1.14; p = 0.569) complications were statistically correlated with sex. On average, men underwent surgery for OVCF at a younger age than women.

CONCLUSIONS

Male patients undergoing surgery for OVCF have higher rates of peri-operative mortality and 30-day readmissions following surgery. Sex was not found to be associated with postoperative complications.

LEVEL OF EVIDENCE

III.

Experimental lung injury induces cerebral cytokine mRNA production in pigs

Background

Acute respiratory distress syndrome (ARDS) is an important disease with a high incidence among patients admitted to intensive care units. Over the last decades, the survival of critically ill patients has improved; however, cognitive deficits are among the long-term sequelae. We hypothesize that acute lung injury leads to upregulation of cerebral cytokine synthesis.

Methods

After approval of the institutional and animal care committee, 20 male pigs were randomized to one of three groups: (1) Lung injury by oleic acid injection (OAI), (2) ventilation only (CTR) or (3) untreated. We compared neuronal numbers, proportion of neurons with markers for apoptosis, activation state of Iba-1 stained microglia cells and cerebral mRNA levels of different cytokines between the groups 18 hours after onset of lung injury.

Results

We found an increase in hippocampal TNFalpha (p < 0.05) and IL-6 (p < 0.05) messenger RNA (mRNA) in the OAI compared to untreated group as well as higher hippocampal IL-6 mRNA compared to control (p < 0.05). IL-8 and IL-1beta mRNA showed no differences between the groups. We found histologic markers for beginning apoptosis in OAI compared to untreated (p < 0.05) and more active microglia cells in OAI and CTR compared to untreated (p < 0.001 each).

Conclusion

Hippocampal cytokine transcription increases within 18 hours after the induction of acute lung injury with histological evidence of neuronal damage. It remains to be elucidated if increased cytokine mRNA synthesis plays a role in the cognitive decline observed in survivors of ARDS.

Valvular calcium load assessment for predicting postprocedural paravalvular leakage: a comparison between surgical aortic valve replacement versus transcatheter implantation

Background

Calcification of native aortic valve is a well known variable causing paravalvular leakage (PVL) following transcatheter aortic valve implantation (TAVI). However, there is currently no evidence to support the fact that patients with high calcium load could be better treated with surgical aortic valve replacement (SAVR).

Purpose

To assess the utility of preoperative assessment of valvular calcium load through computed tomography in patients affected by severe aortic valve stenosis undergoing SAVR or TAVI.

Methods

Between June 2016 and June 2018, 109 candidates for isolated SAVR through minimal invasive access underwent preoperative contrast enhanced multidetector computed tomography (MDCT) for the assessment of valve and aortic calcifications. Calcium load was quantitatively measured using a dedicated software in three regions on interest (aortic valve [AV], left ventricular outflow tract [LVOT] and device landing zone [DLZ], which is the sum of the earlier 2). Clinical, echocardiographic, and MDCT variables were collected and compared to a sample population of 107 patients that underwent TAVI (87 transfemoral, 20 transapical) for native aortic valve stenosis in the same period of time, in the same institution. A univariate and multivariate logistic regression analysis were performed on the whole study population to assess risk factors for the onset of postoperative PVL (any grade, defined as ≥ mild) at discharge.

Results

The two study groups were significantly different in terms of age (71.9±5 in SAVR; 81.5±6 in TAVI), gender (36% female in SAVR vs 51% in TAVI), Euroscore II (1.9%±0.8 in SAVR; 4.8%±2.7 in TAVI), annulus perimeter (79.5mm±8.2 in SAVR; 61.8mm±30.5 in TAVI), baseline ejection fraction (57%±8 in SAVR; 51%±12 in TAVI) and severe pulmonary hypertension (2%±13 in SAVR; 26%±44 in TAVI). Calcium load was not different between groups (DLZ 1066 mm3±716 vs 955mm3±639; total calcium in AV 987 mm3±678 vs 879 mm3±601; total calcium in LVOT 78 mm3±130 vs 77 mm3±100). 30-days-mortality was 1.8% in SAVR and 5.6% in TAVI group (p=0.17). At discharge, incidence of all grades PVL was 5.5% in SAVR (0.9% trace, 3.6% mild, 0.9% moderate) and 41% in TAVI group (12.1% trace, 25.2% mild, 3.7% moderate) (p&lt;0.05). On logistic regression on the whole study population, DLZ calcium (OR 1.1, 95% CI 1–1.2 for 100 mm3, p=0.003) and the use of TAVI (OR 24, 95% CI 7.7–78, p&lt;0.001) were identified as independently associated with the onset of PVL.

Conclusions

Aortic valve calcifications are a risk factor for the onset of PVL for both TAVI and SAVR. Nevertheless, the risk increases considerably with the use of TAVI. A deeper anatomical analysis of preoperative MDCT could improve the treatment selection and the outcome of patients affected by aortic valve stenosis.

Funding Acknowledgement

Type of funding source: None

Aortic valve calcification as a risk factor for major complications and reduced survival after transcatheter replacement

BACKGROUND

Aortic valve calcification is supposed to be a possible cause of embolic stroke or subclinical valve thrombosis after transcatheter aortic valve replacement (TAVR). We aimed to assess the role of aortic valve calcification in the occurrence of in-hospital clinical complications and survival after TAVR.

METHODS

We retrospectively analyzed preoperative contrast-enhanced multidetector computed tomography scans of patients who underwent TAVR on the native aortic valve in our center. Calcium volume was calculated for each aortic cusp, above and below the aortic annulus. Outcomes were recorded according to VARC-2 criteria.

RESULTS

Overall, 581 patients were included in the study (SapienXT = 192; Sapien3 = 228; CoreValve/EvolutR = 45; Engager = 5; Acurate = 111). Median survival was 4.98 years (interquartile range 4.41-5.54). Logistic regression identified calcium load beneath the right coronary cusp in left ventricular outflow tract (LVOT) as significantly associated with stroke (odds ratio [OR] 1.2; 95% confidence interval [CI] 1.03-1.3; p = 0.0019) and in-hospital mortality (OR 1.1; 95% CI 1.004-1.2; p = 0.04), whereas total calcium volume of the LVOT was associated with both in-hospital and 30 day-mortality (OR 1.2; 95% CI 1.01-1.4; p = 0.03, and OR 1.2; 95% CI 1.02-1.43; p = 0.029, respectively). Cox regression identified total calcium of LVOT (hazard ratio [HR] 1.18; 95% CI 1.02-1.38; p = 0.026), male sex (HR 1.88; 95% CI 1.06-3.32; p = 0.031), baseline creatinine clearance (HR 0.96; 95% CI 0.93-0.98; p < 0.001), and baseline severe aortic regurgitation (HR 7.48; 95% CI 2.76-20.26; p < 0.001) as risk factors associated with lower survival.

CONCLUSION

LVOT calcification is associated with increased risk of peri-procedural stroke and mortality as well as shorter long-term survival.

Big in Japan: Regularizing Networks for Solving Inverse Problems

Deep learning and (deep) neural networks are emerging tools to address inverse problems and image reconstruction tasks. Despite outstanding performance, the mathematical analysis for solving inverse problems by neural networks is mostly missing. In this paper, we introduce and rigorously analyze families of deep regularizing neural networks (RegNets) of the formB α + N θ ( α ) B α , where B α is a classical regularization and the networkN θ ( α ) B α is trained to recover the missing partId X - B α not found by the classical regularization. We show that these regularizing networks yield a convergent regularization method for solving inverse problems. Additionally, we derive convergence rates (quantitative error estimates) assuming a sufficient decay of the associated distance function. We demonstrate that our results recover existing convergence and convergence rates results for filter-based regularization methods as well as the recently introduced null space network as special cases. Numerical results are presented for a tomographic sparse data problem, which clearly demonstrate that the proposed RegNets improve classical regularization as well as the null space network.

P4659Left ventricular thrombus and arterial embolism in patients with noncompaction cardiomyopathy - Prognostic value of cardiac magnetic resonance imaging

Background

Left ventricular noncompaction cardiomyopathy (LVNC) is characterized by an increased number of LV trabeculations with deep intertrabecular recesses. This abnormality is associated with heart failure, arrhythmias and arterial embolic events (AE). At present, it is unknown if AE is mainly due to blood stasis within the intertrabecular recesses, reduced LV ejection fraction or concomitant atrial fibrillation. LVNC is usually diagnosed by echocardiography but cardiac magnetic resonance imaging (CMRI) has evolved as an alternative method.

This study assessed the prognostic value of CMRI for arterial embolic events in patients (pts) with LVNC.

Methods

34 consecutive pts (19m, 15f, age 53±16) with LVNC underwent cine and contrast-enhanced CMRI with a 1.5 T scanner. LV diameter, volume, ejection fraction, and ratio of noncompacted to compacted myocardium (NC/C) were determined, and in 32 pts presence and localization of late gadolinium enhancement (LGE) was assessed. Clinical and CMRI findings were compared in pts with and without LV thrombus and/or AE.

Results

Overall, 20 pts (59%) were in heart failure NYHA III or IV, 14 (41%) had left bundle branch block (LBBB), 7 (21%) paroxysmal atrial fibrillation and 6 (19%) ventricular tachycardia (VT). By CMRI, LV diameter in end-diastole (66±8 mm), end-systole (53±10 mm), end-diastolic (229±69 ml) and end-systolic volume (150±68 ml) were enlarged and ejection fraction (36±14%) was reduced. The NC/C ratio was 3.2±1.4 in end-diastole and 2.6±1.4 in end-systole. One pt had right ventricular involvement with a thrombus. LGE was seen in 9/32 pts (28%) in the compacted myocardial layer (n=6), in the noncompacted trabecular layer (n=6) and within the papillary muscles (n=3). LGE was present in 3 areas in 1 and in 2 areas in 4 pts.

In 3 pts (9%) a thrombus was seen within the trabecular layer which resolved under anticoagulation, and 6 additional pts (18%) without detectable thrombus experienced AE (transient ischemic attack n=1, stroke n=5). Thrombus and/or AE were not associated with age, sex, NYHA class, larger left atrial or LV diameter, LV volume, LBBB or documented VT. Atrial fibrillation (2/9 vs 5/25 pts, p=ns), LV ejection fraction (33±13% vs 38±15%, p=ns) and the NC/C ratio in end-diastole (median 3.2 vs 3) or end-systole (both median 2.6, p=ns) were similar. Thrombus and/or AE occurred mainly in pts with LGE (6/9 vs 2/23 pts, p=0.002).

Conclusion

In LVNC, evaluation by CMRI and demonstration of LGE in the compacted or noncompacted myocardium identifies patients at high risk for thrombus formation and/or arterial embolic events, warranting anticoagulation.

Rationale and design of the DIGIT-HF trial (DIGitoxin to Improve ouTcomes in patients with advanced chronic Heart Failure): a randomized, double-blind, placebo-controlled study

AIMS

Despite recent advances in the treatment of chronic heart failure (HF), mortality and hospitalizations still remain high. Additional therapies to improve mortality and morbidity are urgently needed. The efficacy of cardiac glycosides - although regularly used for HF treatment - remains unclear. DIGIT-HF was designed to demonstrate that digitoxin on top of standard of care treatment improves mortality and morbidity in patients with HF and a reduced ejection fraction (HFrEF).

METHODS

Patients with chronic HF, New York Heart Association (NYHA) functional class III-IV and left ventricular ejection fraction (LVEF) ≤ 40%, or patients in NYHA functional class II and LVEF ≤ 30% are randomized 1:1 in a double-blind fashion to treatment with digitoxin (target serum concentration 8-18 ng/mL) or matching placebo. Randomization is stratified by centre, sex, NYHA functional class (II, III, or IV), atrial fibrillation, and treatment with cardiac glycosides at baseline. A total of 2190 eligible patients will be included in this clinical trial (1095 per group). All patients receive standard of care treatment recommended by expert guidelines upon discretion of the treating physician. The primary outcome is a composite of all-cause mortality or hospital admission for worsening HF (whatever occurs first). Key secondary endpoints are all-cause mortality, hospital admission for worsening HF, and recurrent hospital admission for worsening HF.

CONCLUSION

The DIGIT-HF trial will provide important evidence, whether the cardiac glycoside digitoxin reduces the risk for all-cause mortality and/or hospital admission for worsening HF in patients with advanced chronic HFrEF on top of standard of care treatment.

Deep learning for photoacoustic tomography from sparse data

The development of fast and accurate image reconstruction algorithms is a central aspect of computed tomography. In this paper, we investigate this issue for the sparse data problem in photoacoustic tomography (PAT). We develop a direct and highly efficient reconstruction algorithm based on deep learning. In our approach, image reconstruction is performed with a deep convolutional neural network (CNN), whose weights are adjusted prior to the actual image reconstruction based on a set of training data. The proposed reconstruction approach can be interpreted as a network that uses the PAT filtered backprojection algorithm for the first layer, followed by the U-net architecture for the remaining layers. Actual image reconstruction with deep learning consists in one evaluation of the trained CNN, which does not require time-consuming solution of the forward and adjoint problems. At the same time, our numerical results demonstrate that the proposed deep learning approach reconstructs images with a quality comparable to state of the art iterative approaches for PAT from sparse data.

Bromocriptine treatment in patients with peripartum cardiomyopathy and right ventricular dysfunction

Background

Right ventricular (RV) dysfunction predicts adverse outcome in peripartum cardiomyopathy (PPCM). We recently demonstrated beneficial effects associated with the prolactin release inhibitor bromocriptine at different doses when added to standard heart failure therapy in PPCM. Here, we evaluated for the first time the therapeutic potential of bromocriptine particularly in PPCM patients with RV involvement.

Methods

In this study, 40 patients with PPCM were included, of whom 24 patients had reduced RV ejection fraction (RVEF < 45%). We examined the effect of short-term (1W: bromocriptine, 2.5 mg, 7 days, n = 10) compared with long-term bromocriptine treatment (8W: 5 mg for 2 weeks followed by 2.5 mg for another 6 weeks, n = 14) in addition to guideline-based heart failure therapy in patients with an initial RVEF < 45% on the following outcomes: (1) change from baseline (Δ delta) in RVEF, (2) change from baseline in left ventricular EF (LVEF), and (3) rate of patients with full LV recovery (LVEF ≥ 50%) and (4) rate of patients with full RV recovery (RVEF ≥ 55%) at 6-month follow-up as assessed by cardiac magnetic resonance imaging.

Results

Reduced RVEF at initial presentation was associated with a lower rate of full cardiac recovery at 6-month follow-up (patients with RV dysfunction: 58% vs. patients with normal RV function: 81%; p = 0.027). RVEF increased from 38 ± 7 to 53 ± 11% with a delta-RVEF of + 15 ± 12% in the 1W group, and from 35 ± 9 to 58 ± 7% with a Δ RVEF of + 23 ± 10% in the 8W group (Δ RVEF 1W vs 8W: p = 0.118). LVEF increased from 25 ± 8 to 46 ± 12% with a Δ LVEF of + 21 ± 11% in the 1W group, and from 22 ± 6 to 49 ± 10% with a Δ LVEF of + 27 ± 9% in the 8W group (Δ LVEF 1W vs 8W: p = 0.211). Full LV recovery was present in 50% of the 1W group and in 64% of the 8W group (p = 0.678). Full RV recovery was observed in 40% of the 1W group and in 79% of the 8W group (p = 0.092).

Conclusions

Despite overall worse outcome in patients with RV dysfunction at baseline, bromocriptine treatment in PPCM patients with RV involvement was associated with a high rate of full RV and LV recovery, although no significant differences were observed between the short-term and long-term bromocriptine treatment regime. These findings suggest that bromocriptine in addition to standard heart failure therapy may be also effective in PPCM patients with biventricular impairment.

Electronic supplementary material

The online version of this article (10.1007/s00392-018-1355-7) contains supplementary material, which is available to authorized users.

Bromocriptine for the treatment of peripartum cardiomyopathy: a multicentre randomized study

Aims

An anti-angiogenic cleaved prolactin fragment is considered causal for peripartum cardiomyopathy (PPCM). Experimental and first clinical observations suggested beneficial effects of the prolactin release inhibitor bromocriptine in PPCM.

Methods and results

In this multicentre trial, 63 PPCM patients with left ventricular ejection fraction (LVEF) ≤35% were randomly assigned to short-term (1W: bromocriptine, 2.5 mg, 7 days) or long-term bromocriptine treatment (8W: 5 mg for 2 weeks followed by 2.5 mg for 6 weeks) in addition to standard heart failure therapy. Primary end point was LVEF change (delta) from baseline to 6 months assessed by magnetic resonance imaging. Bromocriptine was well tolerated. Left ventricular ejection fraction increased from 28 ± 10% to 49 ± 12% with a delta-LVEF of + 21 ± 11% in the 1W-group, and from 27 ± 10% to 51 ± 10% with a delta-LVEF of + 24 ± 11% in the 8W-group (delta-LVEF: P = 0.381). Full-recovery (LVEF ≥ 50%) was present in 52% of the 1W- and in 68% of the 8W-group with no differences in secondary end points between both groups (hospitalizations for heart failure: 1W: 9.7% vs. 8W: 6.5%, P = 0.651). The risk within the 8W-group to fail full-recovery after 6 months tended to be lower. No patient in the study needed heart transplantation, LV assist device or died.

Conclusion

Bromocriptine treatment was associated with high rate of full LV-recovery and low morbidity and mortality in PPCM patients compared with other PPCM cohorts not treated with bromocriptine. No significant differences were observed between 1W and 8W treatment suggesting that 1-week addition of bromocriptine to standard heart failure treatment is already beneficial with a trend for better full-recovery in the 8W group.

Clinical trial registration

ClinicalTrials.gov, study number: NCT00998556.

Multimodal Imaging for the Assessment of a Cardiac Mass - A Case of Primary Cardiac Sarcoma

We present a case of an 85-year-old patient who underwent clinical work-up for chronic heart failure, acute coronary syndrome, and pulmonary embolism, until she was diagnosed with a cardiac mass that was histologically identified as sarcoma. The aim of this educational case report is to raise awareness of cardiac masses and to point out diagnostic hints towards a cardiac tumor on chest X-ray, coronary angiography, echocardiography, and chest CT. Moreover, the vital role of cardiac magnetic resonance for the diagnosis of a cardiac mass is highlighted.

Sutureless versus Transfemoral Transcatheter Aortic Valve Implant: A Propensity Score Matching Study

BACKGROUND AND AIM OF THE STUDY

Transcatheter aortic valve implantation (TAVI), especially via the transfemoral (TF) route, is increasingly performed in patients considered in the 'gray zone' between TAVI and surgery. However, the best treatment option in this patient population remains to be established.

METHODS

Since 2010, a total of 923 patients underwent either TAVI (n = 538) or sutureless aortic valve replacement (AVR) (n = 385) at the authors' institutions. Among these patients, 79 treated with TF-TAVI were compared with 79 propensity score-matched patients who had undergone elective isolated AVR with the sutureless Perceval bioprosthesis.

RESULTS

In-hospital mortality did not differ significantly between patients who underwent sutureless AVR or TF-TAVI (none versus three; 3.8%; p = 0.123). Similarly, postoperative complications were comparable between groups. Atrioventricular block requiring postoperative pacemaker implantation occurred in seven patients (9.2%) of the sutureless group and in eight patients (11.1%) of the TF-TAVI group (p = 0.455). The use of blood products varied between groups in terms of red blood cell transfusions (1.7 ± 2 versus 0.3 ± 0.9 units for the sutureless group versus TF-TAVI group; p <0.001). Paravalvular leakage at discharge was present in three patients (3.8%) in the sutureless group and in 26 patients (32.9%) in the TF-TAVI group (p <0.001). The mean follow up was longer for sutureless AVR (36 ± 21 versus 27 ± 20 months; p = 0.003). Survival rates were 97.5% and 84.8% in the sutureless and TF-TAVI groups, respectively (p = 0.001).

CONCLUSIONS

Both, TF-TAVI and sutureless AVR are well-standardized, safe and effective procedures. TF-TAVI seems to be a valuable alternative to surgical AVR for frail patients, reducing the need for perioperative blood transfusion. In contrast, in patients with a favorable long-term survival outcome, minimally invasive AVR remains the procedure of choice as it is associated with better long-term results.

Functional and Morphological Parameters with Tissue Characterization of Cardiovascular Magnetic Imaging in Clinically Verified "Infarct-like Myocarditis"

PURPOSE

Cardiac magnetic resonance (CMR) has increasingly proved to be a valuable diagnostic tool for evaluating patients with suspected myocarditis. The objective of this study was to evaluate the diagnostic value of functional and morphological parameters including tissue characterization in patients with "infarct-like myocarditis".

MATERIALS AND METHODS

43 patients with clinically verified cases of "infarct-like myocarditis" (median time to MRI scanning after admission for acute symptoms 3 days) and 35 control patients matched by age and sex were included in this retrospective case control study. In this study we used a 1.5 T MRI scanner conducting steady-state-free-precession sequences, T2-weighted imaging, T1-weighted imaging before and after contrast administration and late gadolinium enhancement sequences. According to the recommendations for CMR diagnosis of myocarditis (Lake Louise consensus criteria), a scan was positive for acute myocarditis if 2 of 3 CMR criteria were present.

RESULTS

30 % of the patients with "infarct-like myocarditis" had a reduced left ventricular ejection fraction, 11 % had an increased LV end-diastolic volume index and 35 % had an increased LV mass index. The sensitivity of wall motion abnormalities was 63 % with a regional distribution in 49 %. In 47 % of cases regional wall motion abnormalities were present in the lateral left ventricular segments. Pericardial effusions were discovered in 65 % of cases with a circular appearance in 21 % and focal manifestation in 44 %. The diagnostic sensitivity, specificity, and accuracy of CMR in patients with "infarct-like myocarditis" were 67 %, 100 % and 82 %, respectively. The LGE alone was the most sensitive test parameter with 86 %, providing a specificity of 100 % and accuracy of 92 %.

CONCLUSION

Our study results can be applied to the subgroup of patients with "infarct-like myocarditis", where we found that LGE alone was the most sensitive test parameter. In addition to tissue characterization, the functional and morphological analysis of patients with acute myocarditis provides a useful further diagnostic tool.

KEY POINTS

•Infarct-like myocarditis can be diagnosed by CMR with high validity and reliability. •LGE allone performed best with a sensitivity of 86 %. •Functional and morphological CMR parameters in addition to tissue characterization are useful tool in the diagnosis of acute myocarditis.

Prognostic implication of right ventricular involvement in peripartum cardiomyopathy: a cardiovascular magnetic resonance study

Aims

Peripartum cardiomyopathy (PPCM) is a major cause of acute heart failure in the peripartum period and considered potentially life threatening. While many aspects of its clinical profiles have been frequently reported, functional analysis, in particular of the right ventricle, and tissue characterization by cardiovascular magnetic resonance (CMR) imaging have been only sporadically described. The aim of the present study was to analyse pathological alterations and their prognostic relevance found in CMR imaging of patients newly diagnosed with PPCM.

Methods and results

In this multicenter study 34 patients with confirmed PPCM underwent CMR imaging at the time of diagnosis and at 5 ± 1 months follow‐up. Cine imaging of PPCM patients showed moderate to severe reduction of systolic left ventricular (LV) function (mean LVEF: 29.7 ± 12.8%). In 35% of the patients right ventricular (RV) systolic function was also reduced with a mean RVEF of 42.9 ± 13.9%. Dilatation of the LV was observed in 91% (mean LV‐EDV/BSA 128.5 ± 32.1 mL/m²), and dilatation of the RV was present in 24% (mean RV‐EDV/BSA 87.4 ± 18.5 mL/m²) of the patients. Focal non‐ischemic late gadolinium enhancement (LGE) was visible in 71%, and regional wall motion abnormalities were evident in 88% of the patients. LGE and wall motion abnormalities were predominantly located in the anteroseptal and basal to midventricular segments. RV dysfunction at baseline was associated with reduced probability of full cardiac recovery at 5 ± 1 months follow‐up.

Conclusions

Besides LV systolic dysfunction, RV dysfunction and dilatation are observed in about one third of PPCM patients at the time of diagnosis. RV dysfunction is associated with unfavourable outcome. A distinct pattern of LV wall motion abnormalities and myocardial scar is evident in most PPCM patients. The present study may help to establish a set of CMR criteria suitable for diagnosis in patients with suspected PPCM and may add further knowledge to the pathology of the disease.

Impact of long-term statin pretreatment on myocardial damage in ST elevation myocardial infarction (from the AIDA STEMI CMR Substudy)

Nonrandomized studies suggested lower mortality rates with statin pretreatment in patients with acute ST elevation myocardial infarction (STEMI). However, clinical data are still inconclusive and the mechanisms of these presumed beneficial effects require further exploration. Cardiac magnetic resonance (CMR) imaging offers the possibility of studying a variety of markers of myocardial damage and reperfusion injury after myocardial infarction. The aim of this study was to assess a possible link of statin pretreatment with myocardial damage in acute STEMI. The multicenter Abciximab i.v. versus i.c. in ST-elevation Myocardial Infarction CMR substudy enrolled 795 consecutive patients with acute STEMI who underwent primary angioplasty within 12 hours of symptom onset. CMR studies assessing left ventricular ejection fraction, infarct size, microvascular obstruction, area at risk, and myocardial salvage index were performed in a median of 3 days after the clinical event. We performed a retrospective analysis to evaluate the impact of statin pretreatment on myocardial damage. Information on statin pretreatment was available in 791 of 795 patients (99%). Of these, 122 (15%) had long-term statin pretreatment. CMR results showed no significant differences in the area at risk, left ventricular ejection fraction, infarct size, microvascular obstruction, and myocardial salvage index between patients with and without statin pretreatment. Furthermore, no differences in short- and long-term outcomes could be observed. In conclusion, in this CMR study, statin pretreatment in patients with STEMI was not associated with lesser myocardial damage.