Selective assisted intravascular lithotripsy for complex aorto-iliac calcific lesions.

BACKGROUND: Intravascular lithotripsy has proven to be safe, less invasive, and effective for coronary and peripheral arteries, and the indication has been extended to the aortic district but there is still little evidence in the literature as only a few cases have been described so far. METHOD: We report a case of intravascular lithotripsy of the infrarenal aorta due to coral reef, chronic occlusion using a single Shockwave M5 + balloon, followed by a covered stent deployment. The aortic bifurcation and common iliac arteries presented hemodynamic calcific lesions, which were prepared singularly with lithotripsy before aorto-iliac covered stenting in kissing configuration. The aortic length from which arises the inferior mesenteric and lumbar arteries was left uncovered preserving their patency. RESULT: In this case, a single shockwave balloon was sufficient to treat successfully and safely the aortic occlusion by heavy calcific lesions. At 1 and 6 months follow-up, the patient had no clinical symptoms, and the ultrasound assessment showed a triphasic waveform at the common femoral arteries bilaterally and confirmed the patency of the stent grafts. CONCLUSION: Selective assisted lithotripsy of heavy aortic and iliac vessels is possible, but definitive outcomes have yet to be supported by the literature.

Endovascular Revascularisation versus Open Surgery with Prosthetic Bypass for Femoro-Popliteal Lesions in Patients with Peripheral Arterial Disease.

Aim: Complex atherosclerotic femoro-popliteal lesions have traditionally been treated with bypass surgery. A prosthetic graft is used to save the vein graft for more distal revascularisations or when a vein graft is unavailable. The endovascular approach has gained popularity and is offered as a first-line strategy for complex lesions. This study aimed to evaluate whether endovascular procedures can be used as a first-line treatment strategy for complex native femoro-popliteal lesions over open surgery with prosthetic bypass in patients with peripheral arterial disease (PAD). Methods: This single-centre retrospective observational study was conducted between 2013 and 2021; it included patients with symptomatic PAD who required limb revascularisation at the femoro-popliteal segment and who had complex lesions. The primary endpoints analysed were technical success, primary patency, freedom from clinically driven target lesion revascularisation (cdTLR), freedom from major adverse limb and cardiovascular events (MALE and MACE, respectively), freedom from limb loss, and survival. The secondary endpoints were length of in-hospital stay, and duration and costs of the procedure. Results: We identified 185 limbs among 174 suitable candidates for comparison, wherein 105 were treated with an endovascular procedure and 80 with a femoro-popliteal prosthetic bypass. Most patients in both groups presented with chronic limb-threatening ischaemia, and >90% of them had an American Society of Anesthesiologists (ASA) physical status classification of >3. The endovascular group had more octogenarians (p = 0.02) and patients with coronary disease (p = 0.004). The median follow-up was 30 months. The technical failure rate for endovascular procedures was 4.7%, versus 0% in the open group (p = 0.047). Freedom from MACE was similar in both groups. The endovascular group showed superior primary patency (p < 0.0001), cdTLR (p < 0.0001), MALE (p < 0.0001), and freedom from limb loss (p = 0.0018) at 24 and 48 months. Further analysis performed for the open above-the-knee sub-group showed that the aforementioned endpoints were similar between the groups at 12 months and were better in the endovascular group at 24 and 48 months. Procedural time and in-hospital stay were longer in the open group than in the endovascular group (p < 0.0001 and p < 0.001, respectively). The procedural cost in the endovascular group was 10-fold lower than that in the prosthetic bypass group. Conclusions: Endovascular procedures are safe for treating complex femoro-popliteal lesions in patients at a high risk for surgery and show better outcomes at 24 months than prosthetic bypasses do. The latter may be considered as an alternative should endovascular treatment fail.

International Union of Angiology consensus document on vascular compression syndromes.

Vascular compression syndromes (VCS) are rare diseases, but they may cause significant symptoms interfering with the quality of life (QoL) of patients who are often in their younger age. Given their infrequent occurrence, multiform clinical and anatomical presentation, and absence of dedicated guidelines from scientific societies, further knowledge of these conditions is required to investigate and treat them using modern imaging and surgical (open or endovascular) techniques. This consensus document will focus on known VCS, affecting the arterial and venous system. The position paper, written by members of International Union of Angiology (IUA) Youth Committee and senior experts, will show an overview of pathophysiology, diagnostic, and therapeutical approaches for patients with VCS. Furthermore, this document will provide also unresolved issues that require more research that need to be addressed in the future.

Cerebral Outflow Discrepancies in Recurrent Benign Paroxysmal Positional Vertigo: Focus on Ultrasonographic Examination.

This prospective pilot study aimed to evaluate whether cerebral inflow and outflow abnormalities assessed by ultrasonographic examination could be associated with recurrent benign paroxysmal positional vertigo (BPPV). Twenty-four patients with recurrent BPPV, affected by at least two episodes, and diagnosed according to American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) criteria, evaluated at our University Hospital, between 1 February 2020 and 30 November 2021, have been included. At the ultrasonographic examination, 22 of 24 patients (92%) reported one or more alterations of the extracranial venous circulation, among those considered for the diagnosis of chronic cerebrospinal venous insufficiency (CCSVI), although none of the studied patients were found to have alterations in the arterial circulation. The present study confirms the presence of alterations of the extracranial venous circulation in recurrent BPPV; these anomalies (such as stenosis, blockages or regurgitation of flow, or abnormal valves, as per the CCSVI) could cause a disruption in the venous inner ear drainage, hampering the inner ear microcirculation and then possibly causing recurrent otolith detachment.

Computer-aided detection of arrhythmogenic sites in post-ischemic ventricular tachycardia.

Nowadays, catheter-based ablation in patients with post-ischemic ventricular tachycardia (VT) is performed in arrhythmogenic sites identified by electrophysiologists by visual inspection during electroanatomic mapping. This work aims to present the development of machine learning tools aiming at supporting clinicians in the identification of arrhythmogenic sites by exploiting innovative features that belong to different domains. This study included 1584 bipolar electrograms from nine patients affected by post-ischemic VT. Different features were extracted in the time, time scale, frequency, and spatial domains and used to train different supervised classifiers. Classification results showed high performance, revealing robustness across the different classifiers in terms of accuracy, true positive, and false positive rates. The combination of multi-domain features with the ensemble tree is the most effective solution, exhibiting accuracies above 93% in the 10-time 10-fold cross-validation and 84% in the leave-one-subject-out validation. Results confirmed the effectiveness of the proposed features and their potential use in a computer-aided system for the detection of arrhythmogenic sites. This work demonstrates for the first time the usefulness of supervised machine learning for the detection of arrhythmogenic sites in post-ischemic VT patients, thus enabling the development of computer-aided systems to reduce operator dependence and errors, thereby possibly improving clinical outcomes.

Automatic signal quality assessment of raw trans-abdominal biopotential recordings for non-invasive fetal electrocardiography.

Introduction: Wearable monitoring systems for non-invasive multi-channel fetal electrocardiography (fECG) can support fetal surveillance and diagnosis during pregnancy, thus enabling prompt treatment. In these embedded systems, power saving is the key to long-term monitoring. In this regard, the computational burden of signal processing methods implemented for the fECG extraction from the multi-channel trans-abdominal recordings plays a non-negligible role. In this work, a supervised machine-learning approach for the automatic selection of the most informative raw abdominal recordings in terms of fECG content, i.e., those potentially leading to good-quality, non-invasive fECG signals from a low number of channels, is presented and evaluated. Methods: For this purpose, several signal quality indexes from the scientific literature were adopted as features to train an ensemble tree classifier, which was asked to perform a binary classification between informative and non-informative abdominal channels. To reduce the dimensionality of the classification problem, and to improve the performance, a feature selection approach was also implemented for the identification of a subset of optimal features. 10336 5-s long signal segments derived from a real dataset of multi-channel trans-abdominal recordings acquired from 55 voluntary pregnant women between the 21st and the 27th week of gestation, with healthy fetuses, were adopted to train and test the classification approach in a stratified 10-time 10-fold cross-validation scheme. Abdominal recordings were firstly pre-processed and then labeled as informative or non-informative, according to the signal-to-noise ratio exhibited by the extracted fECG, thus producing a balanced dataset of bad and good quality abdominal channels. Results and Discussion: Classification performance revealed an accuracy above 86%, and more than 88% of those channels labeled as informative were correctly identified. Furthermore, by applying the proposed method to 50 annotated 24-channel recordings from the NInFEA dataset, a significant improvement was observed in fetal QRS detection when only the channels selected by the proposed approach were considered, compared with the use of all the available channels. As such, our findings support the hypothesis that performing a channel selection by looking directly at the raw abdominal signals, regardless of the fetal presentation, can produce a reliable measurement of fetal heart rate with a lower computational burden.

Primary Drug-Coated Balloon Versus Drug-Eluting Stent for Native Atherosclerotic Femoropopliteal Lesions: A Systematic Review and Meta-Analysis.

BACKGROUND: In this systematic review and meta-analysis, we aimed to compare drug-coated balloon (DCB) to drug-eluting stent (DES) angioplasty as a primary option in patients with femoropopliteal lesions in terms of primary patency and freedom from clinically driven target lesion revascularization (cdTLR) and major adverse limb events (MALE). METHODS: A comprehensive literature search was performed using the PubMed and Embase databases. All studies written in English language and reporting data presenting a comparison between patients receiving primary percutaneous balloon angioplasty using the DCB versus primary percutaneous stenting with DES for native femoropopliteal lesions were included in this meta-analysis. RESULTS: There were 984 patients with 1,078 femoropopliteal lesions, of which procedures with DCB and DES were performed in 514 and 564 lesions, respectively. Overall, majority patients were men with a mean age of 70.9 years, and there were no significant differences between the 2 groups regarding the cardiovascular comorbidities. With regards to the procedural strategy, there was significant heterogeneity in the DCB group. This included adjunctive procedures such as atherectomy besides the angioplasty of the target vessel, which was reported in 1 study as a part of 32.1% of the procedures in the DCB group. Provisional bare metal stents (pBMS) for residual stenosis and dissection were used in 4 studies with a percentage varying from 14.8 to 25.3%. Overall, at 1 year, all outcomes were similar for all the end points; however, where adjunctive procedures were performed (atherectomy + pBMS) in the DCB group, the outcomes were better (primary patency p.001, freedom cdTLR p.001, and freedom form MALE p.002). In studies where no adjunctive procedures were performed in the DCB group, the results favored the DES group for the primary patency (p.026) and freedom from cdTLR (p.044). CONCLUSIONS: DES seems to be superior in terms of cdTLR and primary patency at 1 year when compared to the procedures performed solely with DCB. For DCB to achieve optimal results, further adjunctive procedures such as pBMS and atherectomy are needed. More studies are needed to confirm the superiority of the primary stenting with DES at the femoropopliteal segment.

Estimated EEG functional connectivity and aperiodic component induced by vagal nerve stimulation in patients with drug-resistant epilepsy.

Background: Vagal nerve stimulation (VNS) improves seizure frequency and quality of life in patients with drug-resistant epilepsy (DRE), although the exact mechanism is not fully understood. Previous studies have evaluated the effect of VNS on functional connectivity using the phase lag index (PLI), but none has analyzed its effect on EEG aperiodic parameters (offset and exponent), which are highly conserved and related to physiological functions. Objective: This study aimed to evaluate the effect of VNS on PLI and aperiodic parameters and infer whether these changes correlate with clinical responses in subjects with DRE. Materials and methods: PLI, exponent, and offset were derived for each epoch (and each frequency band for PLI), on scalp-derived 64-channel EEG traces of 10 subjects with DRE, recorded before and 1 year after VNS. PLI, exponent, and offset were compared before and after VNS for each patient on a global basis, individual scalp regions, and channels and separately in responders and non-responders. A correlation analysis was performed between global changes in PLI and aperiodic parameters and clinical response. Results: PLI (global and regional) decreased after VNS for gamma and delta bands and increased for an alpha band in responders, but it was not modified in non-responders. Aperiodic parameters after VNS showed an opposite trend in responders vs. non-responders: both were reduced in responders after VNS, but they were increased in non-responders. Changes in aperiodic parameters correlated with the clinical response. Conclusion: This study explored the action of VNS therapy from a new perspective and identified EEG aperiodic parameters as a new and promising method to analyze the efficacy of neuromodulation.

Epidermal Electrodes with Ferrimagnetic/Conductive Properties for Biopotential Recordings.

Interfacing ultrathin functional films for epidermal applications with external recording instruments or readout electronics still represents one of the biggest challenges in the field of tattoo electronics. With the aim of providing a convenient solution to this ever-present limitation, in this work we propose an innovative free-standing electrode made of a composite thin film based on the combination of the conductive polymer PEDOT:PSS and ferrimagnetic powder. The proposed epidermal electrode can be directly transferred onto the skin and is structured in two parts, namely a conformal conductive part with a thickness of 3 µm and a ferrimagnetic-conductive part that can be conveniently connected using magnetic connections. The films were characterized for ECG recordings, revealing a performance comparable to that of commercial pre-gelled electrodes in terms of cross-spectral coherence, signal-to-noise ratio, and baseline wandering. These new, conductive, magnetically interfaceable, and free-standing conformal films introduce a novel concept in the domain of tattoo electronics and can set the basis for the development of a future family of epidermal devices and electrodes.

Parylene C-Based, Breathable Tattoo Electrodes for High-Quality Bio-Potential Measurements.

A breathable tattoo electrode for bio-potential recording based on a Parylene C nanofilm is presented in this study. The proposed approach allows for the fabrication of micro-perforated epidermal submicrometer-thick electrodes that conjugate the unobtrusiveness of Parylene C nanofilms and the very important feature of breathability. The electrodes were fully validated for electrocardiography (ECG) measurements showing performance comparable to that of conventional disposable gelled Ag/AgCl electrodes, with no visible negative effect on the skin even many hours after their application. This result introduces interesting perspectives in the field of epidermal electronics, particularly in applications where critical on-body measurements are involved.

Below-the-Ankle Orbital Atherectomy in Chronic Limb-Threatening Ischemia Patients as a Bailout Strategy for Limb Salvage: Early Clinical Experience.

PURPOSE: To evaluate the feasibility and early outcomes of below the ankle orbital atherectomy in chronic limb-threatening ischemia in patients with calcified foot arteries. METHODS: 12 patients (mean age 69.4 ± 14.7; range 57 to 85 years) who were affected by diabetes underwent orbital atherectomy below the knee and ankle arterial segments. Technical success was defined as orbital atherectomy passage and debulked the calcified lesion, delivery of adjunctive therapy, and < 30% residual stenosis at final angiogram. The procedural outcome included complications, amputation-free survival, and freedom from clinically-driven target lesion revascularization at 30-days and 6-months of follow-up. RESULTS: Orbital atherectomy was performed in 3 cases in Anterior tibial (AT) and dorsalis pedis (Ped) arteries + Posterior tibial (PT) and Lateral Plantar (Lat Plan), 5 cases in PT and Lat Plan arteries, 1 case of PT and Medial Plantar, 1 case of Peroneal and Plan Lat, and 2 cases of AT and Ped. After atherectomy, we used a drug-coated balloon (DCB) angioplasty. Technical success was achieved in 11 (91.6%) cases. No deaths were registered during the follow-up. The limb salvage rate was 100%, and no major amputations were registered. Amputation-free survival was 50%. Freedom from CD-TLR was 100% at 30 days and 91.7% at 6-months. One patient underwent a TLR at three months. No major cardiovascular events, limb events, or significant procedure-related complications were registered. CONCLUSIONS: CSI orbital atherectomy and DCB angioplasty appear a feasible and promissor treatment options in diabetic CLTI patients.

Spectral characterisation of ventricular intracardiac potentials in human post-ischaemic bipolar electrograms.

Abnormal ventricular potentials (AVPs) are frequently referred to as high-frequency deflections in intracardiac electrograms (EGMs). However, no scientific study performed a deep spectral characterisation of AVPs and physiological potentials in real bipolar intracardiac recordings across the entire frequency range imposed by their sampling frequency. In this work, the power contributions of post-ischaemic physiological potentials and AVPs, along with some spectral features, were evaluated in the frequency domain and then statistically compared to highlight specific spectral signatures for these signals. To this end, 450 bipolar EGMs from seven patients affected by post-ischaemic ventricular tachycardia were retrospectively annotated by an experienced cardiologist. Given the high variability of the morphologies observed, three different sub-classes of AVPs and two sub-categories of post-ischaemic physiological potentials were considered. All signals were acquired by the CARTO® 3 system during substrate-guided catheter ablation procedures. Our findings indicated that the main frequency contributions of physiological and pathological post-ischaemic EGMs are found below 320 Hz. Statistical analyses showed that, when biases due to the signal amplitude influence are eliminated, not only physiological potentials show greater contributions below 20 Hz whereas AVPs demonstrate higher spectral contributions above ~ 40 Hz, but several finer differences may be observed between the different AVP types.

Systematic analysis of wavelet denoising methods for neural signal processing.

Objective.Among the different approaches for denoising neural signals, wavelet-based methods are widely used due to their ability to reduce in-band noise. All wavelet denoising algorithms have a common structure, but their effectiveness strongly depends on several implementation choices, including the mother wavelet, the decomposition level, the threshold definition, and the way it is applied (i.e. the thresholding). In this work, we investigated these factors to quantitatively assess their effects on neural signals in terms of noise reduction and morphology preservation, which are important when spike sorting is required downstream.Approach.Based on the spectral characteristics of the neural signal, according to the sampling rate of the signals, we considered two possible decomposition levels and identified the best-performing mother wavelet. Then, we compared different threshold estimation and thresholding methods and, for the best ones, we also evaluated their effect on clearing the approximation coefficients. The assessments were performed on synthetic signals that had been corrupted by different types of noise and on a murine peripheral nervous system dataset, both of which were sampled at about 16 kHz. The results were statistically analysed in terms of their Pearson's correlation coefficients, root-mean-square errors, and signal-to-noise ratios.Main results.As expected, the wavelet implementation choices greatly influenced the processing performance. Overall, the Haar wavelet with a five-level decomposition, hard thresholding method, and the threshold proposed by Hanet al(2007) achieved the best outcomes. Based on the adopted performance metrics, wavelet denoising with these parametrizations outperformed conventional 300-3000 Hz linear bandpass filtering.Significance.These results can be used to guide the reasoned and accurate selection of wavelet denoising implementation choices in the context of neural signal processing, particularly when spike-morphology preservation is required.

Annotated real and synthetic datasets for non-invasive foetal electrocardiography post-processing benchmarking.

Non-invasive foetal electrocardiography (fECG) can be obtained at different gestational ages by means of surface electrodes applied on the maternal abdomen. The signal-to-noise ratio (SNR) of the fECG is usually low, due to the small size of the foetal heart, the foetal-maternal compartment, the maternal physiological interferences and the instrumental noise. Even after powerful fECG extraction algorithms, a post-processing step could be required to improve the SNR of the fECG signal. In order to support the researchers in the field, this work presents an annotated dataset of real and synthetic signals, which was used for the study "Wavelet Denoising as a Post-Processing Enhancement Method for Non-Invasive Foetal Electrocardiography" [1]. Specifically, 21 15 s-long fECG, dual-channel signals obtained by multi-reference adaptive filtering from real electrophysiological recordings were included. The annotation of the foetal R peaks by an expert cardiologist was also provided. Recordings were performed on 17 voluntary pregnant women between the 21st and the 27th week of gestation. The raw recordings were also included for the researchers interested in applying a different fECG extraction algorithm. Moreover, 40 10 s-long synthetic non-invasive fECG were provided, simulating the electrode placement of one of the abdominal leads used for the real dataset. The annotation of the foetal R peaks was also provided, as generated by the FECGSYN tool used for the signals' creation. Clean fECG signals were also included for the computation of indexes of signal morphology preservation. All the signals are sampled at 2048 Hz. The data provided in this work can be used as a benchmark for fECG post-processing techniques but can also be used as raw signals for researchers interested in foetal QRS detection algorithms and fECG extraction methods.

A Novel Tool for Non-Invasive Fetal Electrocardiography Research: the NInFEA Dataset.

In this work, a novel open-source dataset for noninvasive fetal electrocardiography research is presented. It is composed of 60 high-quality electrophysiological recordings acquired between the 21st and the 27th weeks of gestation. For each acquisition, whose average duration is 30.5 s, 24 unipolar abdominal leads and three bipolar thoracic leads were included, along with a maternal respiration signal collected by a thoracic resistive belt. The chosen electrodes positioning map allows reproducing up to ten setups presented in the scientific literature. Each biopotential recording was acquired synchronously with the corresponding fetal cardiac pulsed-wave Doppler (PWD) signal, to provide complete information about the fetal cardiac cycle, both from the electrical and mechanical point of view.This is the first dataset allowing the non-invasive fetal ECG analysis even in early pregnancies with a ground truth about the fetal heart activity, given by the PWD signal. For this reason, it can be used to assess fetal ECG extraction algorithms requiring multiple channels, eventually including maternal references. This dataset is being released on Physionet by the end of June 2020 and will be continuously improved in the framework of the Non-Invasive Fetal ECG Analysis (NInFEA) project of the University of Cagliari (Italy).

Wavelet denoising as a post-processing enhancement method for non-invasive foetal electrocardiography.

BACKGROUND AND OBJECTIVE: The detection of a clean and undistorted foetal electrocardiogram (fECG) from non-invasive abdominal recordings is an open research issue. Several physiological and instrumental noise sources hamper this process, even after that powerful fECG extraction algorithms have been used. Wavelet denoising is widely used for the improvement of the SNR in biomedical signal processing. This work aims to systematically assess conventional and unconventional wavelet denoising approaches for the post-processing of fECG signals by providing evidence of their effectiveness in improving fECG SNR while preserving the morphology of the signal of interest. METHODS: The stationary wavelet transform (SWT) and the stationary wavelet packet transform (SWPT) were considered, due to their different granularity in the sub-band decomposition of the signal. Three thresholds from the literature, either conventional (Minimax and Universal) and unconventional, were selected. To this aim, the unconventional one was adapted for the first time to SWPT by trying different approaches. The decomposition depth was studied in relation to the characteristics of the fECG signal. Synthetic and real datasets, publicly available for benchmarking and research, were used for quantitative analysis in terms of noise reduction, foetal QRS detection performance and preservation of fECG morphology. RESULTS: The adoption of wavelet denoising approaches generally improved the SNR. Interestingly, the SWT methods outperformed the SWPT ones in morphology preservation (p<0.04) and SNR (p<0.0003), despite their coarser granularity in the sub-band analysis. Remarkably, the Han et al. threshold, adopted for the first time for fECG processing, provided the best quality improvement (p<0.003). CONCLUSIONS: The findings of our systematic analysis suggest that particular care must be taken when selecting and using wavelet denoising for non-invasive fECG signal post-processing. In particular, despite the general noise reduction capability, signal morphology can be significantly altered on the basis of the parameterization of the wavelet methods. Remarkably, the adoption of a finer sub-band decomposition provided by the wavelet packet was not able to improve the quality of the processing.

Comparative evaluation of different wavelet thresholding methods for neural signal processing.

Neural signal decoding is the basis for the development of neuroprosthetic devices and systems. Depending on the part of the nervous system these signals are picked up from, different signal-to-noise ratios (SNR) can be experienced. Wavelet denoising is often adopted due to its capability of reducing, to some extent, the noise falling within the signal spectrum. Several variables influence the denoising quality, but usually the focus in on the selection of the best performing mother wavelet. However, the threshold definition and the way it is applied to the signal have a significant impact on the denoising quality, determining the amount of noise removed and the distortion introduced on the signal. This work presents a comparative analysis of different threshold definition and thresholding mechanisms on neural signals, either largely adopted for neural signal processing or not. In order to evaluate the quality of the denoising in terms of the introduced distortion, which is important when decoding is implemented through spike-sorting algorithms, a synthetic dataset built on real action potentials was used, creating signals with different SNR and characterized by an additive white Gaussian noise (AWGN). The obtained results reveal the superiority of an approach, originally conceived for noisy non-linear time series, over the more typical ones. When compared to the original signal, a correlation above 0.9 was obtained, while in terms of root mean square error (RMSE) an improvement of 13% and 33% was reported with respect to the Minimax and Universal thresholds respectively.