Atsushi Sakamoto

Coronary Artery Calcification and its Progression: What Does it Really Mean?

Coronary artery calcification is concomitant with the development of advanced atherosclerosis. Coronary artery calcification pathologically begins as microcalcifications (0.5 to 15.0 μm) and grows into larger calcium fragments, which eventually result in sheet-like deposits (>3 mm). This evolution is observed to occur concurrently with the progression of plaque. These fragments and sheets of calcification can be easily identified by radiography as well as by computed tomography and intravascular imaging. Many imaging modalities have proposed spotty calcification to be a predictor of unstable plaque and have suggested more extensive calcification to be associated with stable plaques and perhaps the use of statin therapy. We will review the pathology of coronary calcification in humans with a focus on risk factors, relationship with plaque progression, correlation with plaque (in)stability, and effect of pharmacologic interventions.

Calcified Nodule as the Cause of Acute Coronary Syndrome: Connecting Bench Observations to the Bedside

sis are high enough that we have learned important new details of these lesion morphologies, calcified nodule remains a poorly understood entity. What is known from pathology is that this entity encompasses morphologies where calcified sheets or plates break and form nodules of calcification which protrude into the lumen and are associated with platelet-rich thrombi (Fig. 1). In pathology series, calcified nodules are more commonly found in older individuals in the mid-right coronary artery or left anterior descending artery where torsion is greatest. However, little remains known of the consequences of identifying these lesions. In this issue of Cardiology, Kobayashi et al. [5] shed new light upon the entity of calcified nodule, using OCT to identify plaque morphologies in 417 ACS patients from a single center in Japan. The authors reported plaque rupture in 45%, followed by plaque erosion in 41.0% and calcified nodule in 6%. The prevalence of these major causes of ACS is consistent with the results of a prior OCT study by Jia et al. [3]. Consistent with the pathology literature, While coronary angiography has been used for decades to identify coronary thrombosis, the major cause of acute coronary syndromes (ACS), its utility in determining the underlying plaque morphologies responsible for these events is very limited. It was only from pathology studies of patients dying of sudden coronary thrombosis that we learned these events occur from 3 main causes: plaque rupture, plaque erosion, and calcified nodule [1]. In a study of 442 autopsy cases of patients with sudden cardiac death, the prevalence of plaque rupture was 65%, plaque erosion 30%, and calcified nodule 5%, respectively [2]. There remains a disconnect between reports generated from autopsies and what occurs in living patients with regard to culprit plaque phenotypes. Recently, in vivo classification of the causes of coronary artery thrombosis has been assisted by the development of optical coherence tomography (OCT), a high-resolution intravascular imaging technique that measures backscattered light, or optical echoes, derived from an infrared light source. Papers have documented the incidence of plaque rupture, erosion, and calcified nodule as identified by OCT in living patients presenting with ACS and suggest there may be important implications from identifying plaque morphologies in vivo [3, 4]. While the prevalence of ruptures and erosions as causes for coronary thromboReceived: November 8, 2017 Accepted: November 8, 2017 Published online: January 5, 2018

Renal denervation with ultrasound therapy (paradise device) is an effective therapy for systemic hypertension

Hypertension is the most important risk factor for cardiovascular events associated morbidity and mortality, affecting more than one billion people worldwide (1). Although anti-hypertensive drug therapy is very effective in reducing the risk of cardiovascular disease and death, approximately 10% of patients suffer from resistant hypertension despite at least three maximally tolerated doses of anti-hypertensive drugs including a diuretic (2).

CRT-600.10 Local Delivery of a Bioinspired Proteoglycan Mimetic SB-030 Ameliorates In-Stent Thrombogenicity and Inflammation in an Ex Vivo Swine Shunt Model

Symic Bio has developed a novel bioinspired molecule (SB-030) designed to mimic native proteoglycans capable of binding exposed collagen thereby providing a localized barrier to platelets and inflammatory cells at the vessel wall. In this preliminary proof-of-concept study, the anti-thrombogenic

A new category stent with novel polyphosphazene surface modification

The COBRA-PzF™ (CeloNova BioSciences, Inc., TX, USA) is a new type of coronary stent composed of a cobalt chromium metallic backbone surrounded by a nanothin layer of Polyzene-F (PzF) without any added drug. Evidence from basic studies supports antithrombotic and anti-inflammatory properties for the PzF surface coating. Preclinical studies support the thromboresistance of PzF-coated surfaces and clinical studies have shown good outcomes for patients receiving this device with very low rates of stent thrombosis. COBRA-PzF may be especially useful in patients at high risk for bleeding. Ongoing clinical trials will determine whether shortening the duration of dual antiplatelet therapy to less than 1 month is feasible and these data may represent a new paradigm with regards to patients at high risk for bleeding.

Histopathologic and physiologic effect of overlapping vs single coronary stents: impact of stent evolution

ABSTRACT Introduction: Bare metal stents (BMS) and drug eluting stents (DES) have been deployed in single and overlap configurations, the latter mostly to cover long-lesions. Both type of stents in overlap configuration increases the risk of adverse events. Areas covered: We present the rationale for either BMS or DES usage utilizing both preclinical and clinical studies for the use of single vs. overlapped stents. Further, employing experimental and pathological studies, we discuss the disadvantages of stent overlapping vs. single stenting and propose that vessel injury, local blood flow disturbance, higher drug/polymer dose are mechanisms leading to poor clinical outcomes including in-stent restenosis (ISR), delayed arterial healing, thrombosis, and hypersensitivity reactions. We also explore whether newer generation (2nd generation) DES with reduced strut thickness, optimized drug release profiles, better polymer biocompatibility minimize the disadvantages of stent overlap seen in 1st generation DES. Finally, we examine the reasons why fully bioabsorbable scaffolds resulted in increased adverse events. Expert commentary: DES innovations have minimized the risk of ISR and repeat revascularization. In contradistinction to 1st generation DES, major adverse cardiac events (MACE) is similar between single and overlapped stents in 2nd generation DES, suggestion stent design play an important role in clinical outcomes.

Understanding the Impact of Stent and Scaffold Material and Strut Design on Coronary Artery Thrombosis from the Basic and Clinical Points of View

The technology of percutaneous coronary intervention (PCI) is constantly being refined in order to overcome the shortcomings of present day technologies. Even though current generation metallic drug-eluting stents (DES) perform very well in the short-term, concerns still exist about their long-term efficacy. Late clinical complications including late stent thrombosis (ST), restenosis, and neoatherosclerosis still exist and many of these events may be attributed to either the metallic platform and/or the drug and polymer left behind in the arterial wall. To overcome this limitation, the concept of totally bioresorbable vascular scaffolds (BRS) was invented with the idea that by eliminating long-term exposure of the vessel wall to the metal backbone, drug, and polymer, late outcomes would improve. The Absorb-bioabsorbable vascular scaffold (Absorb-BVS) represented the most advanced attempt to make such a device, with thicker struts, greater vessel surface area coverage and less radial force versus contemporary DES. Unfortunately, almost one year after its initial approval by the U.S. Food and Drug Administration, this scaffold was withdrawn from the market due to declining devise utilization driven by the concerns about scaffold thrombosis (ScT) seen in both early and late time points. Additionally, the specific causes of ScT have not yet been fully elucidated. In this review, we discuss the platform, vascular response, and clinical data of past and current metallic coronary stents with the Absorb-BVS and newer generation BRS, concentrating on their material/design and the mechanisms of thrombotic complications from the pre-clinical, pathologic, and clinical viewpoints.