A case of in-stent restenosis with pathologically proven chronic inflammation seven years after sirolimus-eluting stent implantation

Excimer laser coronary atherectomy with distal protection for neoatherosclerosis rupture: a case report

Background

Neoatherosclerosis, a prominent contributor to in-stent restenosis (ISR), persists as a formidable challenge during percutaneous coronary intervention. Excimer laser coronary atherectomy (ELCA) and embolic protection devices may help reduce coronary flow disturbance from procedure-related distal embolization.

Case summary

A 71-year-old man experienced in-stent neoatherosclerosis rupture-related non-ST segment elevation myocardial infarction. Multidisciplinary intracoronary imaging, including intravascular ultrasound and optical coherence tomography (OCT), suggested that the ISR was caused by a neoatherosclerosis rupture that can potentially lead to distal embolization. Excimer laser coronary atherectomy (fluence, 45 mJ/mm2 and frequency, 25 pulse/s) using a 1.7 mm concentric catheter was performed with distal protection using Filtrap (Nipro Corporation, Tokyo, Japan), which significantly reduced the volume of the neoatherosclerosis. However, subsequent ELCA on the highest setting (fluence, 60 mJ/mm2 and frequency, 40 pulse/s) led to a filter no-reflow phenomenon, although OCT revealed a further effective vaporization of the neoatherosclerosis and an apparent reduction of soft tissue compatible with the thrombus. After removing the embolic protection device, drug-coated balloon angioplasty provided optimal results without coronary flow disturbance.

Discussion

Excimer laser coronary atherectomy reduces soft plaque and thrombus burden, which can reduce the occurrence of distal embolization in select cases. In the case of this patient, procedure-related distal embolization may have been induced by the heightened photomechanical effects resulting from the use of the highest setting in ELCA under increased intracoronary arterial pressure caused by continuous saline injection during ELCA. Concomitant distal protection during ELCA may be more feasible for preventing coronary flow disturbance in patients with a large amount of neoatherosclerosis.

Arsenic trioxide activates yes-associated protein by lysophosphatidic acid metabolism to selectively induce apoptosis of vascular smooth muscle cells

Inhibition of vascular smooth muscle cells (VSMCs) proliferation without dysregulating endothelial cells (ECs) may provide an ideal therapy for in-stent restenosis. Due to its anti-proliferation effect on VSMCs and pro-endothelium effect, arsenic trioxide (ATO) has been used in a drug-eluting stent in a recent clinical trial. However, the underlying mechanism by which ATO achieves this effect has not been determined. In the present work, we showed that ATO induced apoptosis in VSMCs but not in ECs. Mechanistically, ATO achieved this through modulation of cellular metabolism to increase lysophosphatidic acid (LPA) in VSMCs, while LPA concentration was stable in ECs. The elevated LPA facilitated the nuclear accumulation and initiated the transcriptional function of Yes-associated protein (YAP) in VSMCs. YAP regulated the transcription of N6-Methyladenosine (m⁶A) modulators (Mettl14 and Wtap) to increase the m⁶A methylation levels of apoptosis-related genes to induce their high expression and exacerbate VSMCs apoptosis. On the other hand, YAP nuclear accumulation in ECs was not observed. Collectively, our data exhibited the molecular process involved in selective apoptosis of VSMCs induced by ATO.

Automated interpretation of the coronary angioscopy with deep convolutional neural networks

BACKGROUND

Coronary angioscopy (CAS) is a useful modality to assess atherosclerotic changes, but interpretation of the images requires expert knowledge. Deep convolutional neural networks (DCNN) can be used for diagnostic prediction and image synthesis.

METHODS

107 images from 47 patients, who underwent CAS in our hospital between 2014 and 2017, and 864 images, selected from 142 MEDLINE-indexed articles published between 2000 and 2019, were analysed. First, we developed a prediction model for the angioscopic findings. Next, we made a generative adversarial networks (GAN) model to simulate the CAS images. Finally, we tried to control the output images according to the angioscopic findings with conditional GAN architecture.

RESULTS

For both yellow colour (YC) grade and neointimal coverage (NC) grade, we could observe strong correlations between the true grades and the predicted values (YC grade, average r=0.80±0.02, p<0.001; NC grade, average r=0.73±0.02, p<0.001). The binary classification model for the red thrombus yielded 0.71±0.03 F1-score and the area under the receiver operator characteristic curve was 0.91±0.02. The standard GAN model could generate realistic CAS images (average Inception score=3.57±0.06). GAN-based data augmentation improved the performance of the prediction models. In the conditional GAN model, there were significant correlations between given values and the expert's diagnosis in YC grade but not in NC grade.

CONCLUSION

DCNN is useful in both predictive and generative modelling that can help develop the diagnostic support system for CAS.

Enhancing biocompatibility and corrosion resistance of biodegradable Mg-Zn-Y-Nd alloy by preparing PDA/HA coating for potential application of cardiovascular biomaterials

In this paper the poly-dopamine (PDA)/hyaluronic acid (HA) coatings with different HA molecular weight (MW, 4 × 10³, 1 × 10⁵, 5 × 10⁵ and 1 × 10⁶ Da) were prepared onto the NaOH passivated Mg-Zn-Y-Nd alloy aiming at potential application of cardiovascular implants. The characterization of weight loss, polarization curves and surface morphology indicated that the coatings with HA MW of 1 × 10⁵ (PDA/HA-2) and 1 × 10⁶ Da (PDA/HA-4) significantly enhanced the corrosion resistance of Mg-Zn-Y-Nd. In vitro biological test also suggested better hemocompatibility, pro-endothelialization, anti-hyperplasia and anti-inflammation functions of the PDA/HA-2- and PDA/HA-4-coated Mg-Zn-Y-Nd alloy. Nevertheless, the in vivo implantation of SD rats' celiac artery demonstrated that the PDA/HA-2 had preferable corrosion resistance and biocompatibility.

Adiponectin as a potential therapeutic target for the treatment of restenosis

Restenosis is a pathologic re-narrowing of a coronary artery lesion after mechanical injury. Its pathophysiological mechanisms have not been fully elucidated at present, but are thought to include inflammation, vascular smooth muscle cell (VSMC) proliferation, and matrix remodeling, beginning with insufficient endothelium healing. Restenosis presents with angina symptoms or acute coronary syndromes and lead to a revascularization, either with coronary artery bypass or repeat percutaneous coronary intervention. Some studies have reported that hypoadiponectinemia has been an independent risk factor for the onset of acute coronary syndromes and restenosis. Accumulating evidence shows that low concentrations of adiponectin may be involved in impairing endothelium functions, inflammation, and VSMC proliferation that lead to restenosis. Preclinical studies have proven that adiponectin promotes endothelium healing, effectively inhibits inflammation, and maintains contractile phenotypes of VSMCs, indicating that it may be developed as a new therapeutic target for the treatment of restenosis.