Intravascular Lithotripsy for the Treatment of Stent Underexpansion: The Multicenter IVL-DRAGON Registry

Background: Whereas the efficacy and safety of intravascular lithotripsy (IVL) have been confirmed in de novo calcified coronary lesions, little is known about its utility in treating stent underexpansion. This study aimed to investigate the impact of IVL in treating stent underexpansion. Methods and Results: Consecutive patients with stent underexpansion treated with IVL entered the multicenter IVL-Dragon Registry. The procedural success (primary efficacy endpoint) was defined as a relative stent expansion >80%. Thirty days device-oriented composite endpoint (DOCE) (defined as a composite of cardiac death, target lesion revascularization, or target vessel myocardial infarction) was the secondary endpoint. A total of 62 patients were enrolled. The primary efficacy endpoint was achieved in 72.6% of patients. Both stent underexpansion 58.5% (47.5−69.7) vs. 11.4% (5.8−20.7), p < 0.001, and the stenotic area 82.6% (72.4−90.8) vs. 21.5% (11.1−37.2), p < 0.001, measured by quantitative coronary angiography improved significantly after IVL. Intravascular imaging confirmed increased stent expansion following IVL from 37.5% (16.0−66.0) to 86.0% (69.2−90.7), p < 0.001, by optical coherence tomography and from 57.0% (31.5−77.2) to 89.0% (85.0−92.0), p = 0.002, by intravascular ultrasound. Secondary endpoint occurred in one (1.6%) patient caused by cardiac death. There was no target lesion revascularization or target vessel myocardial infarction during the 30-day follow-up. Conclusions: In this real-life, largest-to-date analysis of IVL use to manage underexpanded stent, IVL proved to be an effective and safe method for facilitating stent expansion and increasing luminal gain.

Long term outcomes of a coordinate care program in patients after myocardial infarction (KOS-MI)

Introduction

Despite significant progress in treatment of myocardial infarction (MI), the annual mortality remains a challenge. Since 2017, The Coordinated Care in Myocardial Infarction Program (KOS-MI) has been introduced in Poland, which guarantees and coordinates patients to achieve complete revascularization, electrotherapy when necessary, cardiac rehabilitation and access to cardiologist for patients after MI.

Purpose

The aim of this study was to assess long term outcomes (3-year follow-up) of patients enrolled in KOS-MI.

Methods

This is a prospective multicenter registry of 1973 consecutive patients with myocardial infarction hospitalized in 4 centers of American Heart of Poland from 11.2017 to 11.2018. Patients which constituted a study group were enrolled in KOS-MI program at discharge. A control group consisted patients who received standard of care. Propensity score matching was utilized for patients baseline characteristic matching and results adjustment. Follow-up was obtained from the National Health Fund registry citizens. Combine endpoint of MACCE consisted of death, MI, stroke and repeated revascularization.

Results

In total 753 patients were enrolled in KOS program and 1173 constituted a control group. More than 90% of patients in both groups underwent PCI. Patients in KOS-MI were mostly men (70% vs. 65%; p&lt;0,05), were younger (65 vs. 68; p&lt;0,05), admitted with STEMI (44,8% vs. 37,5%; p&lt;0,05) with previous history of heart failure (23% vs. 17%; p&lt;0,05). Patients in the control group had more comorbidities: chronic kidney disease (9,8% vs. 4,4%; p&lt;0,05), previous AMI (17,6% vs. 12,6%; p&lt;0,05), prior PCI (15,7% vs. 11%; p&lt;0,05) and atrial fibrillation (11,7% vs. 8,4%; p&lt;0,05). They were more often admitted with NSTEMI (62,5% vs. 55,3%; p&lt;0,05) and acute heart failure (4,7% vs. 2,7%; p&lt;0,05). KOS patients had more often completed revascularization performed (50% vs. 33,4%; p&lt;0,05). Following propensity score matching 576 pairs were matched, and patient baseline characteristic were well balanced in all variables.

In long- term follow-up (mean 2,8±0,27 years) mortality was significantly lower in KOS group (9% vs. 16,3%; p&lt;0,05) and MI similar (10,8% vs. 13,1%; p=0,14). MACCE was higher in the control group (43% vs. 30,2%; p&lt;0,05). Prevalence of hospitalization for HF and repeated revascularization was higher in the control group (14,7% vs. 9,4%; p&lt;0,05 and 27,9% vs. 21%; p&lt;0,05, respectively). After adjustment MACCE remained significantly lower for KOS-MI, whereas there was tendency for lower mortality, hospitalization for HF and repeated revascularizations (Figure 1).

Conclusions

Combination and coordination of unrestricted rehabilitation, complete revascularization, electrotherapy and ambulatory cardiologist care in the KOS-MI program improves long term prognosis in patients after MI.

Funding Acknowledgement

Type of funding sources: None. Figure 1

pH-tunable nanoparticles composed of copolymers of lactide and allyl-glycidyl ether with various functionalities for the efficient delivery of anti-cancer drugs

The designing of biocompatible nanocarriers for the efficient delivery of their cargos to the desired targets remains a challenge. In this regard, the most promising strategy relies on the construction of pH- or thermo-responsive nanoparticles (NPs). However, it is also important to preserve the balance between the responsiveness of the carrier and their stability in physiological conditions. Therefore, we described a new family of copolymers of lactide and allyl-glycidyl ether which were subsequently modified by thiol-ene reaction to functionalize the resulting copolymer with acetylcysteine (ACC) or thioglycolic acid (tGA) moieties. Subsequently, these copolymers were used to obtain blank and doxorubicin (DOX) loaded NPs with an average diameter of about 50-100 nm. Interestingly, the NPs were stable in different pH conditions, however, the presence of ACC or tGA units in the polymeric chain allows for the reduction of the undesired burst release due to the supramolecular interactions between polymeric pedant groups and DOX. The release tests of DOX from NPs showed that DOX release rate decrease depending on the pH values and the copolymer functionalization in order of non-modified NPs > ACC-modified NPs > tGA functionalized NPs. Most importantly, the MTT assay showed that all blank NPs are non-toxic against the normal L929 cell line. Subsequently, the antitumor efficiency of the obtained NPs was tested towards L929 (murine fibroblast cell line), HeLa (cervical cancer), and AGS (human gastric adenocarcinoma cancer) cells. The results demonstrated that DOX-loaded NPs efficiently induce the reduction in the viability of the HeLa and AGS cell, and this reduction in the viability was even below 20 % for the AGS cells. Together with their biocompatibility, the obtained NPs offer a novel route for the preparation of nanocarriers for the controlled and efficient delivery of anticancer drugs.

Self-reduction of the native TiO2 (110) surface during cooling after thermal annealing - in-operando investigations

We investigate the thermal reduction of TiO2 in ultra-high vacuum. Contrary to what is usually assumed, we observe that the maximal surface reduction occurs not during the heating, but during the cooling of the sample back to room temperature. We describe the self-reduction, which occurs as a result of differences in the energies of defect formation in the bulk and surface regions. The findings presented are based on X-ray photoelectron spectroscopy carried out in-operando during the heating and cooling steps. The presented conclusions, concerning the course of redox processes, are especially important when considering oxides for resistive switching and neuromorphic applications and also when describing the mechanisms related to the basics of operation of solid oxide fuel cells.

Local surface conductivity of transition metal oxides mapped with true atomic resolution

The introduction of transition metal oxides for building nanodevices in information technology promises to overcome the scaling limits of conventional semiconductors and to reduce global power consumption significantly. However, oxide surfaces can exhibit heterogeneity on the nanoscale e.g. due to relaxation, rumpling, reconstruction, or chemical variations which demands for direct characterization of electronic transport phenomena down to the atomic level. Here we demonstrate that conductivity mapping is possible with true atomic resolution using the tip of a local conductivity atomic force microscope (LC-AFM) as the mobile nanoelectrode. The application to the prototypical transition metal oxide TiO2 self-doped by oxygen vacancies reveals the existence of highly confined current paths in the first stage of thermal reduction. Assisted by density functional theory (DFT) we propose that the presence of oxygen vacancies in the surface layer of such materials can introduce short range disturbances of the electronic structure with confinement of metallic states on the sub-nanometre scale. After prolonged reduction, the surfaces undergo reconstruction and the conductivity changes from spot-like to homogeneous as a result of surface transformation. The periodic arrangement of the reconstruction is clearly reflected in the conductivity maps as concluded from the simultaneous friction force and LC-AFM measurements. The second prototype metal oxide SrTiO3 also reveals a comparable transformation in surface conductivity from spot-like to homogeneous upon reduction showing the relevance of nanoscale inhomogeneities for the electronic transport properties and the utility of a high-resolution LC-AFM as a convenient tool to detect them.

TiO2--a prototypical memristive material

Redox-based memristive switching has been observed in many binary transition metal oxides and related compounds. Since, on the one hand, many recent reports utilize TiO(2) for their studies of the memristive phenomenon and, on the other hand, there is a long history of the electronic structure and the crystallographic structure of TiO(2) under the impact of reduction and oxidation processes, we selected this material as a prototypical material to provide deeper insight into the mechanisms behind memristive switching. In part I, we briefly outline the results of the historical and recent studies of electroforming and resistive switching of TiO(2)-based cells. We describe the (tiny) stoichiometrical range for TiO(2 - x) as a homogeneous compound, the aggregation of point defects (oxygen vacancies) into extended defects, and the formation of the various Magnéli phases. Furthermore, we discuss the driving forces for these solid-state reactions from the thermodynamical point of view. In part II, we provide new experimental details about the hierarchical transformation of TiO(2) single crystals into Magnéli phases, and vice versa, under the influence of chemical, electrical and thermal gradients, on the basis of the macroscopic and nanoscopic measurements. Those include thermogravimetry, high-temperature x-ray diffraction (XRD), high-temperature conductivity measurements, as well as low-energy electron diffraction (LEED), x-ray photoelectron spectroscopy (XPS), and LC-AFM (atomic force microscope equipped with a conducting tip) studies. Conclusions are drawn concerning the relevant parameters that need to be controlled in order to tailor the memristive properties.

The new high-temperature surface structure on reduced TiO2(001)

Scanning tunnelling microscopy, ultraviolet photoelectron spectroscopy and current imaging tunnelling spectroscopy (STM/UPS/CITS) were used to study the topographic and electronic structure of a high-temperature structure formed on the TiO(2)(001) surface after heating at 1173 K. The STM images revealed different domain-like ordering and periodicity on the surface in comparison to those observed previously. The UPS studies showed the presence of a surface state at energy about 1.1 eV below the Fermi level. This result was confirmed by the CITS data showing pronounced periodic maxima of the electron local density of states at energy around 1.1-1.2 eV below the Fermi level and located on top of every row of the new high-temperature structure. The CITS results recorded for small grains, which coexist with the observed structure, showed that their chemical composition is closer to the Ti(2)O(3) material than to TiO(2-x) for x << 1.