Course of ankle-brachial-index 12 months after intravascular lithotripsy in calcified peripheral lesions

Background

Intravascular lithotripsy (IVL) is a relatively novel treatment option for calcified lesions in peripheral artery disease. Little is known about the mid to long-term functional status of the patients and target lesion revascularization rate (TLR) after IVL only procedure.

Purpose

To evaluate the course of ankle-brachial-index (ABI) and to assess the rate of revascularization 1 year after intravascular lithotripsy performed on calcified peripheral lesions.

Methods

Between December 2018 and January 2021 IVL was performed on 61 limbs of 51 patients presenting with Rutherford classes 2–5. Ankle-brachial-index (ABI) was documented before the procedure as well as 1 day, 6 months and 1 year after the procedure within a single center real-life registry. Further endpoint was revascularization with PTA or peripheral bypass surgery. The vast majority of cases were done as IVL only procedure (58%) All procedures were done in upper leg/pelvic stenosis.

Results

ABI measurement after 12 months was done in 42 of 51 patients (82%). Three pts were missed due to media sclerosis. Due to loss of follow-up, ABI after 6 months could not be performed on 4/61 patients (7,8%) and 12-month-ABI in another 8/51 cases (15,6%). Initial baseline ABI of 0.6±0.26 before the procedure increased to 0.8±0.25 (p<0.0001) one day afterward. After 6 months, the ABI of 0.8±0.27 (n=49; p<0.0001) was still significantly improved compared to baseline. After 1 year, ABI with 0.7±0.22 was still improved, however not significantly different from baseline (Figure 1). Target lesion revascularization was needed in 7 patients (13%), 4 with subsequent IVL, 3 with PTA and 2 with peripheral bypass surgery.

Conclusions

In our large single center registry, IVL performed mainly as a stand-alone procedure was safe and effective even after a mid-term follow up. TLR was necessary in 13%, which is lower than in previous published IVL data (20,7% as in DISRUPT-PAD-II) [1]. ABI after 12 months improved but did maintain statistical significance, compared with other procedure like scoring balloon [2].

Funding Acknowledgement

Type of funding sources: None.

Intravascular lithotripsy in calcified peripheral lesions: the real-world single-center JEN-experience

Objective

Peripheral vascular disease (PVD) is a major cause of morbidity and mortality with increasing need for interventional therapies. Vascular calcification increases risk of complications and may impair the effect of antiproliferative therapy. Intravascular lithotripsy (IVL) using pulsatile sonic pressure waves to modify intimal and medial calcium is a promising approach for those patients to overcome the drawbacks of vascular calcification.

Purpose

A single-center, prospective registry of patients undergoing peripheral lithotripsy was established. Periprocedural safety events as well as short and long term follow-up clinical data were evaluated.

Methods

A prospective review of cases using IVL was performed for the period from December 2018 to January 2021 at our center. Angiographic images were quantified by using the QVA 8.0 module, Medis Suite Version 3.2.60.4 developed by Medis Imaging Systems.

Results

61 cases of IVL were performed in 51 patients with Rutherford class 3. Mean age was 71 years with 78% (28) of the patients being men. Diabetes was present in 80% and renal insufficiency in 47% of the cases. The median calcified lesion length treated was 82 mm (10; 390 mm) with a PACCS sore of 3 (1; 3), indicating a highly calcified status. In 41% (n=25), predilation was necessary. We treated 8 iliac-, 19 common femoral-, 52 superficial femoral-, 5 deep femoral-, 29 popliteal- and 2 crural- lesions with balloon sizes ranging from 4.0 to 7.0 mm. In 35 (57%) cases IVL was used as a stand-alone therapy, in the remaining 26 an adjunctive therapy (DCB and/or stent) was used. We were able to reach an acute luminal gain of 2.5 mm. A ballon rupture occurred in 6 (10%) cases. There were no other complications. Mean ABI improved from 0.6 to 0.8 (p<0.0001) immediate after the intervention. Follow-up after 6 months again demonstrated an improved ABI of 0.8 (p<0.0001 vs. baseline).

Conclusion

This first real-world data of IVL reports compelling safety of IVL in a complex, difficult-to-treat patient cohort. For the first time, clinical follow-up data were presented and demonstrated a sustained improved ABI after 6 months. This innovative approach will gain more interest in the future, especially since long term effects of paclitaxel eluting devices are controversially discussed.

Funding Acknowledgement

Type of funding sources: None. ABI initial follow-up

Design, concept and first in-vitro results of the percutaneous, pulsatile left ventricular assist device-PERKAT LV

Introduction

A very high morbidity and mortality is associated with cardiogenic shock due to left ventricular failure despite encouraging developments in interventional cardiology. Patients suffering from cardiogenic shock often require temporary mechanical circulatory support to stabilize organ perfusion. In addition, an increasing number of patients with complex multi-vessel diseases cannot undergo surgical myocardial revascularization as recommended by recent guidelines due to their comorbidities. Those patients could benefit from a protected PCI approach using a temporary mechanical assist device. The available LVAD systems have specific advantages and disadvantages.

Purpose

It was our aim to develop a percutaneous, pulsatile assist device that unloads the left ventricle in a physiologic way.

Methods

The PERKAT-LV (“PERkutane KATheterpumptechnologie”) device consists of a self-expanding nitinol pump chamber which is covered by foils. Those foils carry multiple outflow valves at the proximal part of the pump chamber. A flexible suction tube with a pigtail-shaped tip and inflow holes are attached to its distal part. The system is designed for 16F percutaneous implantation via the femoral artery. Pulling back the outer sheath unfolds the nitinol chamber in the descending aorta while the flexible suction tube bypasses the aortic arch and ascending aorta with its tip in the left ventricle. In the second implantation step, a standard IABP balloon is placed into the pumping chamber and is connected to an external IABP console. Balloon deflation generates a blood flow from the left ventricle into PERKAT LV. During balloon inflation, blood leaves the system through the outflow foil valves in the descending aorta. Positioning and schematic drawing of PERKAT-LV is demonstrated in Figure 1.

Results

Preliminary in-vitro studies using a prototype of the PERKAT LV device were performed. It was tested in different afterload settings (0, 40, 80 and 120 mmHg) using a standard 30 ccl IABP balloon and varying inflation/deflations rates (70, 80, 90, 100, 110 and 120/min). We detected flow rates ranging from 2.0 to 3.0 L/min depending on the afterload setting and inflation/deflation rate.

Conclusion

The novel percutaneously implantable and pulsatile working PERKAT-LV device offers left ventricular unloading and circulatory support of up to 3.0 L/min in a first feasibility study. At the moment, the system is extensively studied under in vitro conditions. First in vivo evaluation will follow in the near future.

Based on the current results, we believe that the system is a promising novel approach for percutaneous application of temporary left ventricular mechanical support.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): German Federal Ministry of Education and Research

P1746Prehospital logistics and therapy delays in urban vs. rural regions: implications for quality of acute ST-elevation myocardial infarction care

Background

Treatment and time goals for STEMI care are clearly defined in national and international guidelines. However, initiation of therapy relies in accurate diagnosis after first medical contact (FMC). Prehospital logistics with fast transfer to the next available 24/7 PCI-center can be challenging, especially in rural areas and for transfers across state-borders in Germany.

Objective

To analyze quality of STEMI care in a high volume PCI center serving a city and a large rural area with focus on EMS (emergency medical service) logistics. Two groups of patients admitted by EMS: (1) direct PCI-center admission vs. (2) secondary admission after transfer from a non-PCI hospital were compared.

Methods

Various administrative, procedural, therapeutic and clinical parameters were registered for each patient including timelines of acute treatment (tables). Inaccurate treatment delays were calculated as cumulative time in any prolongation in timely diagnosis or therapy after FMC.

Results

From 340 consecutive STEMI patients in or registry, 299 patients were transferred by EMS. Reperfusion therapy with PPCI was significantly delayed and required double of the time in patients secondary transferred from a non-PCI hospital (Contact-to-Balloon: 195.6±134.8 min vs. 99.6±45.3 min, p<0.001, table 1). An inaccurate delay in timely treatment (delay in correct diagnosis or deferred therapy) was determined in 45% of the patients transferred from non-PCI hospitals vs 26% of directly admitted patients (p=0.02, table 1). Accordingly, correct STEMI diagnosis was established by EMS physician prehospital only in 7.1% in the transfer group vs. 61.9% in the direct admission group (p<0.001, table 1). Our data suggest different reasons for STEMI patients falsely transferred to non-PCI hospitals: a) lower qualification of EMS personnel with ECG misinterpretation and/or false working diagnosis, b) inadequate prehospital logistics with transfer of patients to the next near-by hospital instead of next PCI-center, c) personal or system “thresholds” of EMS physicians in rural areas preventing a direct transfer to PCI-centers. Further analysis of the transfer group (table 2) showed even longer treatment times for patients transferred across state borders compared to transfers within a state (C2B: 264.8±142.2 vs. 143.7±107.0 min, p<0.05, table 2). Importantly, transfers across state borders were not associated with a longer absolute distance (km) to PCI center. However, a rescue helicopter was used for across-state transfers in one third of the cases.

Conclusion

Quality of acute STEMI care is significantly worse in rural areas predominantly due to suboptimal prehospital logistics and poor prehospital emergency care. Our data underline the importance to establish local STEMI networks irrespective of state borders with clearly defined prehospital transfer strategies, continuous medial education of EMS personnel and assessement of local quality of care.

P6287Analysis of novel cardiac markers sST2 and IL-33 in chronic heart failure with reduced ejection fraction

Background

Soluble (s) ST-2 has been recently evaluated as a monitoring parameter in heart failure (HF). Besides being a marker for cardiac strain and hemodynamic stress, studies also found an influence of ST2 on the immune system, above all mediated through its Janus-Face ligand IL-33, an alarmin released under stress conditions or by cellular death. In contrast to sST2, the role of IL-33 in HF is yet unknown.

Objective

In this project, we aimed for an analysis of the ST2/IL33 pathway in patients with heart failure with reduced ejection fraction (HFrEF).

Methods

In total, 200 patients were included in the study: 59 with ischemic (ICM), 65 with dilated (DCM) cardiomyopathy (mean LVEF 38%), as well as 76 control patients without coronary artery disease or signs of heart failure. Serum samples were analyzed by use of ELISA after informed consent.

Results

sST2 showed a significant elevation in all HF patients (p<0.0001) compared to the control group. No significant differences in levels of sST2 were observed between ICM and DCM patients. In contrast to sST2, no differences between HF patients and control group were observed for IL-33. Furthermore, sST2 showed a significant correlation with CRP (p<0.001, r=0.28), NT-pro-BNP (p<0.0001, r=0.40) and an inverse correlation with ejection fraction (p<0.0001, r=−0.40). Additionally, sST2 showed a significant elevation in patients in NYHA stages I-II (p=0.030) and NYHA stages III-IV (p<0.01). Again, no significant correlations were observed between IL-33 and parameters mentioned above.

Analysis of sST2 in heart failure

Conclusions

We observed a significant increase and correlation with disease severity of sST2 in chronic HFrEF patients of both ischemic and non-ischemic origin, but contrary to our expectations, no significant changes in serum levels of IL-33. Thus, a mechanism independent of ST2/IL33 axis could be responsible of sST2 secretion in HF. Further studies including acute decompensated patients could provide a better understanding of the IL-33 role in HF.

Inflammation, vitamin D and dendritic cell precursors in chronic kidney disease

Decreased blood dendritic cell precursors (DCP) count is linked with atherosclerotic disease, while reduction of circulating DCP is also seen in patients with chronic kidney disease (CKD). As poor vitamin D status could be linked to a compromised innate immune response, we hypothesized that vitamin D status might be involved in the decrease in circulating DCP in CKD. Moreover, the potential role of inflammation was considered. Circulating myeloid (mDCP), plasmacytoid (pDCP) and total DCP (tDCP) were analysed using flow cytometry in 287 patients with CKD stage 3. Serum 25(OH)D and 1,25(OH)2D levels were measured using enzyme-linked immunosorbent assays (ELISA), interleukin (IL)-6, IL-10 and tumour necrosis factor (TNF)-α using cytometric bead array, C-reactive protein (CRP) using a high-sensitivity (hs) ELISA. Contrary to our hypothesis, there was no association between vitamin D levels and DCP, although their number was decreased significantly in CKD (P < 0·001). Instead, mDCP (r = -0·211) and tDCP (r = -0·188,) were associated slightly negatively with hsCRP but positively with the estimated glomerular filtration rate (eGFR, r = 0·314 for tDCP). According to multivariate linear regression, only higher hsCRP concentration and the presence of diabetes mellitus had a significant negative influence on DCP count (P < 0·03, respectively) but not vitamin D, age and eGFR. A significant impact of vitamin D on the reduction of circulating DCP in CKD 3 patients can be neglected. Instead, inflammation as a common phenomenon in CKD and diabetes mellitus had the main influence on the decrease in DCP. Thus, a potential role for DCP as a sensitive marker of inflammation and cardiovascular risk should be elucidated in future studies.

Mutations in PNPLA6 are linked to photoreceptor degeneration and various forms of childhood blindness

Blindness due to retinal degeneration affects millions of people worldwide, but many disease-causing mutations remain unknown. PNPLA6 encodes the patatin-like phospholipase domain containing protein 6, also known as neuropathy target esterase (NTE), which is the target of toxic organophosphates that induce human paralysis due to severe axonopathy of large neurons. Mutations in PNPLA6 also cause human spastic paraplegia characterized by motor neuron degeneration. Here we identify PNPLA6 mutations in childhood blindness in seven families with retinal degeneration, including Leber congenital amaurosis and Oliver McFarlane syndrome. PNPLA6 localizes mostly at the inner segment plasma membrane in photoreceptors and mutations in Drosophila PNPLA6 lead to photoreceptor cell death. We also report that lysophosphatidylcholine and lysophosphatidic acid levels are elevated in mutant Drosophila. These findings show a role for PNPLA6 in photoreceptor survival and identify phospholipid metabolism as a potential therapeutic target for some forms of blindness.

Proximal giant neurofilamentous axonopathy in mice genetically engineered to resist calpain and caspase cleavage of α-II spectrin

We use 1,2-diacetylbenzene (1,2-DAB) to probe molecular mechanisms of proximal giant neurofilamentous axonopathy (PGNA), a pathological hallmark of amyotrophic lateral sclerosis. The spinal cord proteome of rodents displaying 1,2-DAB PGNA suggests a reduction in the abundance of α-II spectrin (Spna2), a key protein in the maintenance of axonal integrity. Protein immunoblotting indicates that this reduction is due to Spna2 degradation. We investigated the importance of such degradation in 1,2-DAB PGNA. Spna2 mutant mice lacking a calpain- and/or caspase-sensitive domain (CSD), thus hypothetically resistant to 1,2-DAB, and wild-type littermates, were treated with 1,2-DAB, 35 mg/kg/day, or saline control, for 3 weeks. 1,2-DAB induced motor weakness and PGNA, irrespective of the genotype. Spna2-calpain breakdown products were not detected in mutant mice, which displayed a normal structure of the nervous system under saline treatment. Intriguingly, treatment with 1,2-DAB reduced the abundance of the caspase-specific 120-kDa Spna2 breakdown products. Our findings indicate that degradation of Spna2 by calpain- and/or caspase is not central to the pathogenesis of 1,2-DAB axonopathy. In addition, the Spna2-CSD seems to be not required for the maintenance of the cytoskeleton integrity. Our conceptual framework offers opportunities to study the role of calpain-caspase cross talk, including that of the protease degradomics, in models of axonal degeneration.

Progressive neurodegeneration in Drosophila: a model system

The Drosophila model system has been used to study neurodegenerative diseases by expression of human disease genes in transgenic flies. A different approach is to isolate and characterize Drosophila mutants with progressive neurodegeneration to find novel genes required for brain integrity. Mammalian homologues of these genes might be the genetic basis for some of the various progressive neurodegeneration diseases in humans. Here we describe several such mutants. Some of them reveal degeneration in specific parts of the brain while others affect all brain regions. Cell death can occur through apoptosis or necrosis. In one case, mutant flies show abnormal behavior prior to obvious degeneration while most other mutants reveal such defects only in later stages. These mutants offer a new approach to study basic mechanisms of neurodegeneration and for developing fly models for human diseases.

Glia in development, function, and neurodegeneration of the adult insect brain

Glial cells have long been viewed as a passive framework for neurons but in the meanwhile were shown to play a much more active role in brain function and development. Several reviews have described the function of glia in the insect embryo. The focus of this review is the role of glial cells in the development and function of the normal and diseased adult brain. In different insect species, a considerable variety of central nervous system glia has been described indicating adaptation to different functional requirements. In the development of the adult visual and olfactory system, glial cells guide incoming axons acting as intermediate targets. Glia are part of the insect blood-brain barrier, provide nourishment for neurons, and help to regulate the extracellular concentration of ions and neurotransmitters. To fulfill these tasks insect glial cells, like vertebrate glia, interact with each other and with neurons, thus influencing neural activity. The examples presented suggest that crosstalk between all brain cells is necessary not only to develop and maintain the complex insect brain but also to endow it with the capacity to respond and adapt to the changing environment.

Defective pigment granule biogenesis and aberrant behavior caused by mutations in the Drosophila AP-3beta adaptin gene ruby

Lysosomal protein trafficking is a fundamental process conserved from yeast to humans. This conservation extends to lysosome-like organelles such as mammalian melanosomes and insect eye pigment granules. Recently, eye and coat color mutations in mouse (mocha and pearl) and Drosophila (garnet and carmine) were shown to affect subunits of the heterotetrameric adaptor protein complex AP-3 involved in vesicle trafficking. Here we demonstrate that the Drosophila eye color mutant ruby is defective in the AP-3beta subunit gene. ruby expression was found in retinal pigment and photoreceptor cells and in the developing central nervous system. ruby mutations lead to a decreased number and altered size of pigment granules in various cell types in and adjacent to the retina. Humans with lesions in the related AP-3betaA gene suffer from Hermansky-Pudlak syndrome, which is caused by defects in a number of lysosome-related organelles. Hermansky-Pudlak patients have a reduced skin pigmentation and suffer from internal bleeding, pulmonary fibrosis, and visual system malfunction. The Drosophila AP-3beta adaptin also appears to be involved in processes other than eye pigment granule biogenesis because all ruby allele combinations tested exhibited defective behavior in a visual fixation paradigm.

Cloning and expression of the murine sws/NTE gene

The Drosophila neurodegeneration gene swiss-cheese encodes a neuronal protein apparently involved in glia-neuron interaction and is homologous to human NTE, the molecular target of organophosphate-induced neuropathy. The isolated Msws/NTE gene is 96% identical to NTE. During development the Msws transcript is expressed in the embryonic respiratory system, different epithelial structures and strongly in the spinal ganglia. Postnatally, Msws mRNA is expressed in all brain areas, with an increasingly restrictive pattern. In adult mice expression is most prominent in Purkinje cells, granule cells and pyramidal neurons of the hippocampus and some large neurons in the medulla oblongata, nucleus dentatus and pons.

The swiss cheese mutant causes glial hyperwrapping and brain degeneration in Drosophila

Swiss cheese (sws) mutant flies develop normally during larval life but show age-dependent neurodegeneration in the pupa and adult and have reduced life span. In late pupae, glial processes form abnormal, multilayered wrappings around neurons and axons. Degeneration first becomes evident in young flies as apoptosis in single scattered cells in the CNS, but later it becomes severe and widespread. In the adult, the number of glial wrappings increases with age. The sws gene is expressed in neurons in the brain cortex. The conceptual 1425 amino acid protein shows two domains with homology to the regulatory subunits of protein kinase A and to conceptual proteins of yet unknown function in yeast, worm, and human. Sequencing of two sws alleles shows amino acid substitutions in these two conserved domains. It is suggested that the novel SWS protein plays a role in a signaling mechanism between neurons and glia that regulates glial wrapping during development of the adult brain.

VP5 of infectious bursal disease virus is not essential for viral replication in cell culture

Infectious bursal disease virus (IBDV), a member of the Birnaviridae family, encodes in its bisegmented double-stranded RNA genome four structural virion proteins, VP1, VP2, VP3, and VP4, as well as a nonstructural protein, VP5. Recently, the establishment of an infectious cRNA system for IBDV has been described (E. Mundt and V. N. Vakharia, Proc. Natl. Acad. Sci. USA 93:11131-11136, 1996). Here, we report the isolation of a VP5- IBDV mutant constructed by site-directed mutagenesis of the methionine start codon of VP5, followed by cRNA transfection. The resulting virus mutant was replication competent in cell culture, which indicates that VP5 is not required for productive replication of IBDV. Absence of VP5 expression was verified by lack of reactivity with newly established anti-VP5 monoclonal antibodies and polyclonal sera. VP5- IBDV exhibited a delay in replication in chicken embryo cells compared to the VP5+ parental virus. However, final yields were similar. Our results thus show that VP5 is nonessential for IBDV replication, which makes it a prime candidate for the construction of deleted, marked vaccines.

Avian cellular homolog of the qin oncogene

We have isolated chicken cDNA clones of the c-qin gene, the cellular counterpart of the v-qin (Chinese for "avian") oncogene of avian sarcoma virus 31. There are several differences between the cellular and the viral qin sequences: (i) two nonconservative amino acid substitutions in the Qin coding region; (ii) a truncation in the carboxyl terminus of the viral protein due to a premature stop codon; (iii) a partial Gag sequence fused to the amino terminus of viral Qin; and (iv) eight cell-coded amino acids which link the cellular Qin coding domain to the viral Gag domain. We have also characterized the expression pattern of c-qin in chicken embryos by in situ hybridization and by Northern blot analysis. c-qin is abundantly expressed in the developing brain, and this expression is restricted to the telencephalon of early embryos.

Giant lens, a gene involved in cell determination and axon guidance in the visual system of Drosophila melanogaster

Mutations in the Drosophila gene giant lens (gil) affect ommatidial development, photoreceptor axon guidance and optic lobe development. We have cloned the gene using an enhancer trap line. Molecular analysis of gil suggests that it encodes a secreted protein with an epidermal-growth-factor-like motif. We have generated mutations at the gil locus by imprecise excision of the enhancer trap P-element. In the absence of gil, additional photoreceptors develop at the expense of pigment cells, suggesting an involvement of gil in cell determination during eye development. In addition, gil mutants show drastic effects on photoreceptor axon guidance and optic lobe development. In wildtype flies, photoreceptor axons grow from the eye disc through the optic stalk into the larval brain hemisphere, where retinal innervation is required for the normal development of the lamina and distal medulla. The projection pattern of these axons in the developing lamina and medulla is highly regular and reproducible. In gil, photoreceptor axons enter the larval brain but fail to establish proper connections in the lamina or medulla. We propose that gil encodes a new type of signalling molecule involved in the process of axon pathfinding and cell determination in the visual system of Drosophila.