The FXYD1 protein plays a protective role against pulmonary hypertension and arterial remodeling via redox and inflammatory mechanisms

Pulmonary hypertension (PH) consists of a heterogenous group of diseases that culminate in increased pulmonary arterial pressure and right ventricular (RV) dysfunction. We sought to investigate the role of FXYD1, a small membrane protein that modulates Na+-K+-ATPase function, in the pathophysiology of PH. We mined online transcriptome databases to assess FXYD1 expression in PH. We characterized the effects of FXYD1 knockout (KO) in mice on right and left ventricular (RV and LV) function using echocardiography and measured invasive hemodynamic measurements under normal conditions and after treatment with bleomycin sulfate or chronic hypoxia to induce PH. Using immunohistochemistry, immunoblotting, and functional assays, we examined the effects of FXYD1 KO on pulmonary microvasculature and RV and LV structure and assessed signaling via endothelial nitric oxide synthase (eNOS) and inflammatory pathways. FXYD1 lung expression tended to be lower in samples from patients with idiopathic pulmonary arterial hypertension (IPAH) compared with controls, supporting a potential pathophysiological role. FXYD1 KO mice displayed characteristics of PH including significant increases in pulmonary arterial pressure, increased muscularization of small pulmonary arterioles, and impaired RV systolic function, in addition to LV systolic dysfunction. However, when PH was stimulated with standard models of lung injury-induced PH, there was no exacerbation of disease in FXYD1 KO mice. Both the lungs and left ventricles exhibited elevated nitrosative stress and inflammatory milieu. The absence of FXYD1 in mice results in LV inflammation and cardiopulmonary redox signaling changes that predispose to pathophysiological features of PH, suggesting FXYD1 may be protective.NEW & NOTEWORTHY This is the first study to show that deficiency of the FXYD1 protein is associated with pulmonary hypertension. FXYD1 expression is lower in the lungs of people with idiopathic pulmonary artery hypertension. FXYD1 deficiency results in both left and right ventricular functional impairment. Finally, FXYD1 may endogenously protect the heart from oxidative and inflammatory injury.

Impact of Incomplete Revascularization After PCI in Left Main Disease: The EXCEL Trial

BACKGROUND

The importance of complete revascularization after percutaneous coronary intervention (PCI) in patients with left main coronary artery disease is uncertain. We investigated the clinical impact of complete revascularization in patients with left main coronary artery disease undergoing PCI in the EXCEL trial (Evaluation of XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization).

METHODS

Composite rates of death or myocardial infarction (MI) following PCI during 5-year follow-up were examined in 903 patients based on core laboratory definitions of anatomic and functional complete revascularization, residual SYNTAX score (The Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery), and residual Jeopardy Score (rJS).

RESULTS

The risk of death or MI did not vary based on anatomic, functional, or residual SYNTAX score complete revascularization but did differ according to the rJS (5-year rates 17.6%, 19.5%, and 38.9% with rJS 0, 2, and ≥4, respectively; P=0.006). The higher rate of death or MI with rJS≥4 versus rJS≤2 was driven conjointly by increased mortality (adjusted hazard ratio, 2.29 [95% CI, 1.11-4.71]; P=0.02) and spontaneous MI (adjusted hazard ratio, 2.89 [95% CI, 1.17-7.17]; P=0.02). The most common location for untreated severe stenoses in the rJS≥4 group was the left circumflex artery (LCX), and the post-PCI absence, compared with the presence, of any untreated lesion with diameter stenosis ≥70% in the LCX was associated with reduced 5-year rates of death or MI (18.9% versus 35.2%; hazard ratio, 0.48 [95% CI, 0.32-0.74]; P<0.001). The risk was the highest for residual ostial/proximal LCX lesions.

CONCLUSIONS

Among patients undergoing PCI in EXCEL trial, incomplete revascularization according to the rJS was associated with increased rates of death and spontaneous MI. Post-PCI untreated high-grade lesions in the LCX (especially the ostial/proximal LCX) drove these outcomes.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01205776.

Utility of optical coherence tomography in acute coronary syndromes

Studies utilizing intravascular imaging have replicated the findings of histopathological studies, identifying the most common substrates for acute coronary syndromes (ACS) as plaque rupture, erosion, and calcified nodule, with spontaneous coronary artery dissection, coronary artery spasm, and coronary embolism constituting the less common etiologies. The purpose of this review is to summarize the data from clinical studies that have used high-resolution intravascular optical coherence tomography (OCT) to assess culprit plaque morphology in ACS. In addition, we discuss the utility of intravascular OCT for effective treatment of patients presenting with ACS, including the possibility of culprit lesion-based treatment by percutaneous coronary intervention.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention: Practical Application

Optical coherence tomography (OCT) provides high-resolution imaging of coronary arteries and can be used to optimize percutaneous coronary intervention (PCI). Intracoronary OCT, however, has had limited adoption in clinical practice. Novelty and relative complexity of OCT interpretation compared with the more established intravascular ultrasound, lack of a standardized algorithm for PCI guidance, paucity of data from randomized trials, and lack of rebate for intravascular imaging have contributed to the modest practical adoption of OCT. We provide a practical step-by-step guide on how to use OCT in PCI, including device set-up, simplified image interpretation, and an algorithmic approach for PCI. optimization.

Visualizing Inside Conduits-Intraoperative Screening of Grafts by Optical Coherence Tomography

PURPOSE

Saphenous vein graft (SVG) failure is a complex phenomenon, with technical, biologic, and local factors contributing to early and medium- and long-term failure after coronary artery bypass graft. Both technical and conduit factors may have significant impact on early SVG failure.

DESCRIPTION

We review the complex factors that play a pathogenic role in SVG failure, followed by review of the existing literature on potential utility of high-definition optical coherence tomography (OCT) in comprehensive intraoperative assessment of SVGs.

EVALUATION

We describe a new technique for intraoperative acquisition of OCT images in the harvested SVGs and introduce a classification system for pathologic processes that can be detected in the harvested SVG conduits by OCT.

CONCLUSIONS

The potential impact on early graft failure of the exclusion of segments of SVGs that are less than optimal (ie, containing fibroatheroma, retained thrombus, sclerotic valves, or procurement injury) will be examined in the randomized controlled OCTOCAB (Intraoperative Optical Coherence Tomography of the Saphenous Vein Conduit in Patients Undergoing Coronary Artery Bypass Surgery) trial.

Optical coherence tomography versus angiography and intravascular ultrasound to guide coronary stent implantation: A systematic review and meta-analysis

BACKGROUND

Optical coherence tomography (OCT) is an adjunct to angiography-guided coronary stent placement. However, in the absence of dedicated, appropriately powered randomized controlled trials, the impact of OCT on clinical outcomes is unclear.

OBJECTIVE

To conduct a systematic review and meta-analysis of all available studies comparing OCT-guided versus angiography-guided and intravascular ultrasound (IVUS)-guided coronary stent implantation.

METHODS

MEDLINE and Cochrane Central were queried from their inception through July 2022 for all studies that sought to compare OCT-guided percutaneous coronary intervention (PCI) to angiography-guided and IVUS-guided PCI. The primary endpoint was minimal stent area (MSA) compared between modalities. Clinical endpoints of interest were all-cause and cardiovascular mortality, major adverse cardiovascular events (MACE), myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), and stent thrombosis (ST). Risk ratios (RRs) and mean differences (MDs) with their corresponding 95% confidence intervals (CIs) were pooled using a random-effects model.

RESULTS

Thirteen studies (8 randomized control trials and 5 observational studies) enrolling 6312 participants were included. OCT was associated with a strong trend toward increased MSA compared to angiography (MD = 0.36, p = 0.06). OCT-guided PCI was also associated with a reduction in the incidence of all-cause mortality [RR = 0.59, 95% CI (0.35, 0.97), p = 0.04] and cardiovascular mortality [RR = 0.41, 95% CI (0.21, 0.80), p = 0.009] compared with angiography-guided PCI. Point estimates favored OCT relative to angiography in MACE [RR = 0.75, 95% CI (0.47, 1.20), p = 0.22] and MI [RR = 0.75, 95% CI (0.53, 1.07), p = 0.12]. No differences were detected in ST [RR = 0.71, 95% CI (0.21, 2.44), p = 0.58], TLR [RR = 0.71, 95% CI (0.17, 3.05), p = 0.65], or TVR rates [RR = 0.89, 95% CI (0.46, 1.73), p = 0.73]. Compared with IVUS guidance, OCT guidance was associated with a nonsignificant reduction in the MSA (MD = -0.16, p = 0.27). The rates of all-cause and cardiovascular mortality, MACE, MI, TLR, TVR, or ST were similar between OCT-guided and IVUS-guided PCI.

CONCLUSIONS

OCT-guided PCI was associated with reduced all-cause and cardiovascular mortality compared to angiography-guided PCI. These results should be considered hypothesis generating as the mechanisms for the improved outcomes were unclear as no differences were detected in the rates of TLR, TVR, or ST. OCT- and IVUS-guided PCI resulted in similar post-PCI outcomes.

Calcium Modification in Percutaneous Coronary Interventions

Moderate-severe calcification increases procedural complications and impairs long-term prognosis post-PCI. Intravascular imaging (particularly optical coherence tomography [OCT]) is useful in guiding the treatment of calcified lesions. Weighted sum of calcium length, arc, and thickness on OCT can predict adequate stent expansion, identifying when atherectomy is required. With intravascular imaging guidance, various techniques alone or in combination may be used in an algorithmic fashion to modify calcified lesions. Calcium fracture by balloon angioplasty, cutting/scoring balloons, intravascular lithotripsy (IVL), atherectomy devices, or Excimer laser improves stent expansion. Intravascular imaging is essential in the treatment of in-stent restenosis when luminal and/or abluminal peri-strut calcium is present.

Role of Intracoronary Imaging in Acute Coronary Syndromes

Intravascular imaging with optical coherence tomography (OCT) and intravascular ultrasound provides superior visualization of the culprit plaques for acute coronary syndromes (ACS) compared with coronary angiography. Combined with angiography, intravascular imaging can be used to instigate ‘precision therapy’ for ACS. Post-mortem histopathology identified atherothrombosis at the exposed surface of a ruptured fibrous cap as the main cause of ACS. Further histopathological studies identified intact fibrous caps and calcified nodules as other culprit lesions for ACS. These plaque types were subsequently also identified on intravascular imaging, particularly with the high-resolution OCT. The less-common non-atherothrombotic causes of ACS are coronary artery spasm, coronary artery dissection, and coronary embolism. In this review, the authors provide an overview of clinical studies using intravascular imaging with OCT in the diagnosis and management of ACS.

Calcific Plaque Modification by Acoustic Shockwaves: Intravascular Lithotripsy in Cardiovascular Interventions

PURPOSE OF REVIEW

To provide a review of recent literature on the treatment of moderate-to-severe calcification in coronary and peripheral vasculature with intravascular lithotripsy (Shockwave Medical, Santa Clara, CA).

RECENT FINDINGS

Moderate-to-severe calcific plaques constitute a significant proportion of lesions treated with transcatheter interventions in the coronary and peripheral vascular beds and portend lower procedural success rates, increased periprocedural major adverse events, and unfavorable long-term clinical outcomes compared to non-calcific plaques. Intravascular lithotripsy (IVL) is a new technique that uses acoustic shock waves in a balloon-based system to induce fracture in the calcium deposits to facilitate luminal gain and stent expansion. IVL demonstrated high procedural success and low complication rates in the management of moderate-to-severe calcification in coronary and peripheral vascular beds and led to large luminal gain by modification of calcific plaque as assessed by optical coherence tomography. Further studies will determine the role of IVL in an integrated, protocolized approach to the treatment of severely calcified plaques in the coronary and peripheral vascular beds.

Strategies for Renal Protection in Cardiovascular Interventions

Contrast-associated acute kidney injury (CA-AKI), a potential complication of cardiovascular interventions that require radiocontrast administration, is associated with increased morbidity, mortality, and length of hospital admission. CA-AKI is particularly prevalent among patients with chronic kidney disease and comorbidities such as advanced age and diabetes. This review briefly discusses the evidence-based strategies to minimize CA-AKI. In addition, technical details of procedures to minimize the contrast volume, i.e., ultra-low contrast angiography and zero contrast percutaneous intervention, along with several illustrative cases are presented.

Coronary artery disease is highly prevalent in chronic kidney disease (CKD) and is a risk factor for contrast-associated acute kidney injury (CA-AKI), a complication of cardiovascular procedures that require contrast administration (e.g., coronary angiography, percutaneous coronary intervention [PCI]). CA-AKI has a major impact on morbidity, mortality, and healthcare resource utilization. The incidence of CA-AKI is particularly high in patients with pre-existing CKD, advanced age and comorbidities that increase the likelihood of CKD. The focus of the present review is to provide a brief overview on the assessment of the risk for and prevention of CA-AKI in patients undergoing angiography and PCI, including recognition of the important patient- and procedure-related factors that may contribute to CA-AKI. Preventive and treatment strategies, the mainstay of which is volume repletion by normal saline, are briefly discussed. The main focus of the review is placed on technical details of contrast minimization techniques, including ultra-low contrast angiography and zero-contrast PCI. Operator competence in such techniques is important to ensure that procedural challenges in patients with CKD, like vessel calcification, multivessel disease and complex anatomical subsets, are effectively addressed by PCI while minimizing the risk of CA-AKI.

Low bone mineral density and coronary artery disease: A systematic review and meta-analysis

Coronary artery disease (CAD) and osteoporosis both cause significant morbidity and mortality. Recent interest in inflammation and the bone-vascular axis suggests a mechanistic link between the two conditions. This review and meta-analysis was conducted to examine the potential association between low bone mineral density (BMD) and CAD in adults. Two authors searched for studies that examined the association between low BMD and CAD. Risk of bias assessment was conducted using the modified Newcastle Ottawa score. Ten studies were selected from the 2258 unique records identified. Pooled analysis showed a significant association between low BMD and CAD (OR 1.65, 95%CI 1.37-2.39, p < 0.01). Subgroup analysis investigating males and females separately was not significant. The subgroup analyses looking for any differences across geographic locations and differences between coronary imaging modalities were also negative. Studies with adjusted ORs (n = 4) were also pooled (OR 3.01, 95%CI 0.91-9.99, p = 0.07). Low BMD is associated with CAD; however, it is unclear whether this result is confounded by common risk factors given the heterogeneity between study populations and methodologies. Further large-scale epidemiological studies are required.

The multiple roles of chemokines in the mechanisms of stent biocompatibility

While the advent of drug-eluting stents has been clinically effective in substantially reducing the rates of major stent-related adverse events compared with bare metal stents, vascular biological problems such as neointimal hyperplasia, delayed re-endothelialization, late stent thrombosis are not eliminated and, increasingly, neoatherosclerosis is the underlying mechanism for very late stent failure. Further understanding regarding the mechanisms underlying the biological responses to stent deployment is therefore required so that new and improved therapies can be developed. This review will discuss the accumulating evidence that the chemokines, small inflammatory proteins, play a role in each key biological process of stent biocompatibility. It will address the chemokine system in its specialized roles in regulating the multiple facets of vascular biocompatibility including neointimal hyperplasia, endothelial progenitor cell (EPC) mobilization and re-endothelialization after vascular injury, platelet activation and thrombosis, as well as neoatherosclerosis. The evidence in this review suggests that chemokine-targeting strategies may be effective in controlling the pathobiological processes that lead to stent failure. Preclinical studies provide evidence that inhibition of specific chemokines and/or broad-spectrum inhibition of the CC-chemokine class prevents neointimal hyperplasia, reduces thrombosis and suppresses the development of neoatherosclerosis. In contrast, however, to these apparent deleterious effects of chemokines on stent biocompatibility, the CXC chemokine, CXCL12, is essential for the mobilization and recruitment of EPCs that make important contributions to re-endothelialization post-stent deployment. This suggests that future chemokine inhibition strategies would need to be correctly targeted so that all key stent biocompatibility areas could be addressed, without compromising important adaptive biological responses.

External elastic lamina vs. luminal diameter measurement for determining stent diameter by optical coherence tomography: an ILUMIEN III substudy

AIMS

Optical coherence tomography (OCT)-guided external elastic lamina (EEL)-based stent sizing is safe and as effective as intravascular ultrasound in achieving post-procedural lumen dimensions. However, when compared with automated lumen diameter (LD) measurements, this approach is time-consuming. We aimed to compare vessel diameter measurements and stent diameter selection using either of these approaches and examined whether applying a correction factor to automated LD measurements could result in selecting similar stent diameters to the EEL-based approach.

METHODS AND RESULTS

We retrospectively compared EEL-based measurements vs. automated LD in reference segments in 154 OCT acquisitions and derived a correction factor for stent sizing using the ratio of EEL to LD measurements. We then prospectively applied the correction factor in 119 OCT acquisitions. EEL could be adequately identified in 100 acquisitions (84%) at the distal reference to allow vessel diameter measurement. Vessel diameters were larger with EEL-based vs. LD measurements at both proximal (4.12 ± 0.74 vs. 3.14 ± 0.67 mm, P < 0.0001) and distal reference segments (3.34 ± 0.75 vs. 2.64 ± 0.65 mm, P < 0.0001). EEL-based downsizing led to selection of larger stents vs. an LD-based upsizing approach (3.33 ± 0.47 vs. 2.70 ± 0.44, P < 0.0001). Application of correction factors to LD [proximal 1.32 (IQR 1.23-1.37) and distal 1.25 (IQR 1.19-1.36)] resulted in discordance in stent sizing by >0.25 mm in 63% and potentially hazardous stent oversizing in 41% of cases.

CONCLUSION

EEL-based stent downsizing led to selection of larger stent diameters vs. LD upsizing. While applying a correction factor to automated LD measurements resulted in similar mean diameters to EEL-based measurements, this approach cannot be used clinically due to frequent and potentially hazardous stent over-sizing.

Acoustic shock waves to modify calcific plaques - Intravascular lithotripsy in the peripheral circulation

Intravascular lithotripsy (IVL) is a new technique for treatment of severely calcified lesions that uses acoustic shockwaves in a balloon-based system to induce fracture in calcific plaque, facilitating luminal gain and vessel expansion. In this review, we provide a concise summary of the available data and clinical experience of IVL in various peripheral vascular beds, including facilitating vascular access for large-bore devices. We discuss the physics and mode of action of IVL in modifying calcified plaques, include several illustrative examples of utility of IVL in peripheral interventions, and discuss the future directions for adoption of the technique in peripheral interventions.

Intracoronary optical coherence tomography: state of the art and future directions

Optical coherence tomography (OCT) has been increasingly utilised to guide percutaneous coronary intervention (PCI). Despite the diagnostic utility of OCT, facilitated by its high resolution, the impact of intracoronary OCT on clinical practice has thus far been limited. Difficulty in transitioning from intravascular ultrasound (IVUS), complex image interpretation, lack of a standardised algorithm for PCI guidance, and paucity of data from prospective clinical trials have contributed to the modest adoption. Herein, we provide a comprehensive up-do-date overview on the utility of OCT in coronary artery disease, including technical details, device set-up, simplified OCT image interpretation, recognition of the imaging artefacts, and an algorithmic approach for using OCT in PCI guidance. We discuss the utility of OCT in acute coronary syndromes, provide a summary of the clinical trial data, list the work in progress, and discuss the future directions.

Invasive Management of Coronary Artery Disease in Advanced Renal Disease

Coronary artery disease (CAD) is highly prevalent in chronic kidney disease (CKD). CKD modifies the effects of traditional risk factors on atherosclerosis, with CKD-specific mechanisms, such as inflammation and altered mineral metabolism, playing a dominant pathophysiological role as kidney function declines. Traditional risk models and cardiovascular screening tests perform relatively poorly in the CKD population, and medical treatments including lipid-lowering therapies have reduced efficacy. Clinical presentation of cardiac ischemia in CKD is atypical, whereas invasive therapies are associated with higher rates of complications than in with patients with normal or near normal kidney function. The main focus of the present review is on the invasive approach to management of CAD in late-stage CKD, with an in-depth discussion of the findings of the International Study of Comparative Health Effectiveness With Medical and Invasive Approaches (ISCHEMIA)-CKD trial, and their implications for therapeutic approach and future research in this area. We also briefly discuss the existing evidence in the epidemiology, pathogenesis, diagnosis, and medical management of CAD in late-stage CKD, end-stage kidney disease (ESKD), and kidney transplant recipients. We enumerate the evidence gap left by the frequent exclusion of patients with CKD from randomized controlled trials and highlight the priority areas for future research in the CKD population.

Atherothrombosis in Acute Coronary Syndromes-From Mechanistic Insights to Targeted Therapies

The atherothrombotic substrates for acute coronary syndromes (ACS) consist of plaque ruptures, erosions and calcified nodules, while the non-atherothrombotic etiologies, such as spontaneous coronary artery dissection, coronary artery spasm and coronary embolism are the rarer causes of ACS. The purpose of this comprehensive review is to (1) summarize the histopathologic insights into the atherothrombotic plaque subtypes in acute ACS from postmortem studies; (2) provide a brief overview of atherogenesis, while mainly focusing on the events that lead to plaque destabilization and disruption; (3) summarize mechanistic data from clinical studies that have used intravascular imaging, including high-resolution optical coherence tomography, to assess culprit plaque morphology and its underlying pathobiology, especially the newly described role of innate and adaptive immunity in ACS secondary to plaque erosion; (4) discuss the utility of intravascular imaging for effective treatment of patients presenting with ACS by percutaneous coronary intervention; and (5) discuss the opportunities that these mechanistic and imaging insights may provide for more individualized treatment of patients with ACS.

Therapeutic Approach to Calcified Coronary Lesions: Disruptive Technologies

PURPOSE OF REVIEW

Moderate or severe calcification is present in approximately one third of coronary lesions in patients with stable ischemic heart disease and acute coronary syndromes and portends unfavorable procedural results and long-term outcomes. In this review, we provide an overview on the state-of-the-art in evaluation and treatment of calcified coronary lesions.

RECENT FINDINGS

Intravascular imaging (intravascular ultrasound or optical coherence tomography) can guide percutaneous coronary intervention of severely calcified lesions. New technologies such as orbital atherectomy and intravascular lithotripsy have significantly expanded the range of available techniques to effectively modify coronary calcium and facilitate stent expansion. Calcium fracture improves lesion compliance and is essential to optimize stent implantation. Intravascular imaging allows for detailed assessment of patterns and severity of coronary calcium that are integrated into scoring systems to predict stent expansion, identifying which lesions require atherectomy for lesion modification. Guided by intravascular imaging, older technologies such as rotational atherectomy and excimer laser can be incorporated with newer technologies such as orbital atherectomy and intravascular lithotripsy into an algorithmic approach for the safe and effective treatment of patients with heavily calcified coronary lesions.

Outcomes of optical coherence tomography compared with intravascular ultrasound and with angiography to guide coronary stent implantation: one-year results from the ILUMIEN III: OPTIMIZE PCI trial

AIMS

In the ILUMIEN III trial, among 450 randomised patients with non-complex lesions undergoing percutaneous coronary intervention (PCI), optical coherence tomography (OCT) guidance led to greater stent expansion than angiography guidance, similar minimal stent area compared to both intravascular ultrasound (IVUS) guidance and angiography guidance, and lower rates of uncorrected dissection and malapposition than both IVUS guidance and angiography guidance. Whether these differences impact on clinical outcomes is unknown. The aim of the present study was to report the 12-month clinical follow-up data from the ILUMIEN III study.

METHODS AND RESULTS

OCT-guided PCI, using an external elastic lamina-based protocol, was compared to operator-directed IVUS-guided or angiography-guided PCI. Target lesion failure (TLF) and major adverse cardiovascular events (MACE) at 12 months were adjudicated by a blinded clinical events committee. There were no significant differences in the rates of TLF (2.0% OCT, 3.7% IVUS, 1.4% angiography), MACE (9.8% OCT, 9.1% IVUS, 7.9% angiography), or any of the individual components of these outcomes among the groups. No independent predictors of 12-month stent-related clinical events were identified from final OCT.

CONCLUSIONS

In this underpowered study, OCT-guided PCI of non-complex lesions did not show a statistical difference in clinical outcomes at 12 months compared with IVUS or angiography guidance. An appropriately powered trial, including only complex patients and lesions, is underway to substantiate the potential clinical benefit of OCT-guided PCI.

TRIAL REGISTRATION

NCT02471586.

Optical coherence tomography-guided coronary stent implantation compared to angiography: a multicentre randomised trial in PCI - design and rationale of ILUMIEN IV: OPTIMAL PCI

AIMS

Randomised trials have demonstrated improvement in clinical outcomes with intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) compared with angiography-guided PCI. The ILUMIEN III trial demonstrated non-inferiority of an optical coherence tomography (OCT)- versus IVUS-guided PCI strategy in achieving similar post-PCI lumen dimensions. ILUMIEN IV is a large-scale, multicentre, randomised trial designed to demonstrate the superiority of OCT- versus angiography-guided stent implantation in patients with high-risk clinical characteristics (diabetes) and/or complex angiographic lesions in achieving larger post-PCI lumen dimensions and improving clinical outcomes.

METHODS AND RESULTS

ILUMIEN IV is a prospective, single-blind clinical investigation that will randomise between 2,490 and 3,656 patients using an adaptive design to OCT-guided versus angiography-guided coronary stent implantation in a 1:1 ratio. The primary endpoints are: (1) post-PCI minimal stent area assessed by OCT in each randomised arm, and (2) target vessel failure, the composite of cardiac death, target vessel myocardial infarction, or ischaemia-driven target vessel revascularisation. Clinical follow-up will continue for up to two years. The trial is currently enrolling, and the principal results are expected in 2022.

CONCLUSIONS

The large-scale ILUMIEN IV randomised controlled trial will evaluate the effectiveness of OCT-guided versus angiography-guided PCI in improving post-PCI lumen dimensions and clinical outcomes in patients with diabetes and/or with complex coronary lesions.

TRIAL REGISTRATION

NCT03507777.

The Role of Colchicine in Atherosclerotic Cardiovascular Disease

Colchicine, an inexpensive immunomodulatory drug used traditionally to treat gout and familial Mediterranean fever, is rapidly accumulating basic and clinical evidence for a therapeutic role in atherosclerotic cardiovascular disease. Its athero-protective properties are thought to be mainly related to its effect on tubulin polymerisation, enabling a broad range of effect on multiple atherosclerotic plaque cell types and cellular processes, including cell division, cell migration as well as pro-inflammatory cytokine and chemokine secretion. These properties indicate the potential to favourably affect all stages of atherosclerotic plaque development including formation, progression, destabilisation, and plaque rupture. This review focusses on the pharmacology of colchicine, the mechanisms by which it modulates atherosclerosis pathobiology, and summarises the current clinical evidence for its use along with the upcoming clinical trial landscape. Given the current lack of primary immunomodulatory drugs in the treatment of atherosclerosis, colchicine is a promising candidate to fill this therapeutic gap.

Progression of coronary atherosclerosis in patients without standard modifiable risk factors

Background and aims

The outcome of patients with clinical coronary artery disease despite traditional risk factors is poorly understood.

Methods

Clinical characteristics and plaque burden on serial intravascular ultrasonography were compared in patients without (n ​= ​165) and with (n ​= ​492) standard modifiable risk factors after matching on age, sex and use of statins from a database of 5823 patients participating in clinical trials of anti-atherosclerotic therapies.

Results

Patients without standard modifiable risk factors had lower baseline systolic blood pressure (118 ​± ​12 vs. 129 ​± ​17 ​mmHg, p ​< ​0.001), low-density lipoprotein cholesterol (87 ​± ​21 vs. 104 ​± ​34 ​mg/dl, p ​< ​0.001), triglycerides [106 vs. 136 ​mg/dl, p ​< ​0.001)] and C-reactive protein [1.5 vs. 2.1 ​mg/l, p ​= ​0.001]. At baseline, patients without modifiable risk factors had a lower percent atheroma volume (35.7 ​± ​8.6 vs. 38 ​± ​8.8%, p ​= ​0.004) and total atheroma volume (174.7 ​± ​80 vs. 190.9 ​± ​84 ​mm³, p ​= ​0.03) and less images with calcification (22.2 vs. 26.5%, p ​= ​0.025). The use of aspirin and statin prior to and during the trials was similar. The use of ACE inhibitors and beta blockers was lower in the no risk factor group prior to and during the trials. The change in percent atheroma volume (−0.2 ​± ​2.8 vs. −0.1 ​± ​3.6%, p ​= ​0.71), total atheroma volume (−5.5 ​± ​23.4 vs. −3.8 ​± ​22.7 ​mm³, p ​= ​0.42), and the percentage of patients demonstrating any degree of progression (50.9% vs 45.1%, p ​= ​0.20) were similar in those without and with standard modifiable risk factors, respectively.

Conclusion

Patients who develop clinical coronary atherosclerosis without standard modifiable risk factors have similar rates of plaque progression to those with traditional risk factors.

•

Outcome of patients with CAD despite no traditional risk factors is poorly understood.

•

Serial intravascular ultrasound studies provide an opportunity to examine this.

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Patients without standard risk factors had lower plaque burden and calcification.

•

Use of aspirin and statin was similar in patients with and without standard risk factors.

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Plaque progression was similar in those without and with standard risk factors.

Deferred Intravascular Lithotripsy-Facilitated Stenting in ACS: Novel Approach to Improve PCI Outcomes in Severe Calcification?

Moderate/severe calcification, present in approximately one-third of culprit lesions in acute coronary syndromes (ACS), portends unfavorable procedural and post-primary percutaneous coronary intervention outcomes. Intravascular lithotripsy is a novel technique using shockwaves to fracture calcific plaques. Presenting a clinical case, we enumerate efficacy and safety parameters in using intravascular lithotripsy in ACS. (Level of Difficulty: Advanced.).

Calcific Plaque Modification by Acoustic Shock Waves: Intravascular Lithotripsy in Coronary Interventions

Constituting a significant proportion of lesions treated with transcatheter interventions in the coronary arteries, moderate-to-severe calcification portends lower procedural success rates, increased periprocedural major adverse events, and unfavorable long-term clinical outcomes compared with noncalcific plaques. Adapted from the lithotripsy technology for treatment of nephrolithiasis, intravascular lithotripsy is a new technique for treatment of severely calcific lesions that uses acoustic shock waves in a balloon-based system to induce fracture in the calcium deposits to facilitate luminal gain and stent expansion. Herein, we summarize the physics and characteristics of the currently available intravascular lithotripsy system (Shockwave Medical, Santa Clara, CA), the clinical data on intravascular lithotripsy use in the coronary arteries, and future directions for adoption of the technique in percutaneous coronary intervention.

Targeting Cardiac Myocyte Na+-K+ Pump Function With β3 Adrenergic Agonist in Rabbit Model of Severe Congestive Heart Failure

BACKGROUND

Abnormally high cytosolic Na⁺ concentrations in advanced heart failure impair myocardial contractility. Stimulation of the membrane Na⁺-K⁺ pump should lower Na⁺ concentrations, and the β3 adrenoceptor (β3 AR) mediates pump stimulation in myocytes. We examined if β3 AR-selective agonists given in vivo increase myocyte Na⁺-K⁺ pump activity and reverse organ congestion in severe heart failure (HF).

METHODS

Indices for HF were lung-, heart-, and liver: body weight ratios and ascites after circumflex coronary artery ligation in rabbits. Na⁺-K⁺ pump current, I_p, was measured in voltage-clamped myocytes from noninfarct myocardium. Rabbits were treated with the β3 AR agonists CL316,243 or ASP9531, starting 2 weeks after coronary ligation.

RESULTS

Coronary ligation caused ascites in most rabbits, significantly increased lung-, heart-, and liver: body weight ratios, and decreased I_p relative to that for 10 sham-operated rabbits. Treatment with CL316,243 for 3 days significantly reduced lung-, heart-, and liver: body weight ratios and prevalence of ascites in 8 rabbits with HF relative to indices for 13 untreated rabbits with HF. It also increased I_p significantly to levels of myocytes from sham-operated rabbits. Treatment with ASP9531 for 14 days significantly reduced indices of organ congestion in 6 rabbits with HF relative to indices of 6 untreated rabbits, and it eliminated ascites. β3 AR agonists did not significantly change heart rates or blood pressures.

CONCLUSIONS

Parallel β3 AR agonists-induced reversal of Na⁺-K⁺ pump inhibition and indices of congestion suggest pump inhibition is a useful target for treatment with β3 AR agonists in congestive HF.

The novel P2X7 receptor antagonist PKT100 improves cardiac function and survival in pulmonary hypertension by direct targeting of the right ventricle

In pulmonary hypertension (PH) a proinflammatory milieu drives pulmonary vascular remodeling, maladaptive right ventricular (RV) remodeling, and right-sided heart failure. There is an unmet need for RV-targeted pharmaco-therapies to improve mortality. Targeting of the P2X7 receptor (P2X7R) reduces pulmonary pressures; however, its effects on the RV are presently unknown. We investigated the effect of P2X7 receptor (P2X7R) inhibition on the pulmonary vasculature and RV remodeling using the novel P2X7R antagonist PKT100. C57BL/6 mice were administered intratracheal bleomycin or saline and treated with PKT100 (0.2 mg·kg^-1·day^-1) or DMSO vehicle. RV was assessed by right heart catheterization and echocardiography, 21 days posttreatment. Cytokines in serum and bronchoalveolar lavage fluid (BALF) were analyzed by ELISA and flow cytometry. Lungs and hearts were analyzed histologically for pulmonary vascular and RV remodeling. Focused-PCR using genes involved in RV remodeling was performed. Right ventricular systolic pressure (RVSP) was elevated in bleomycin-treated mice (30.2 ± 1.1; n = 7) compared with control mice (23.5 ± 1.0; n = 10; P = 0.008). PKT100 treatment did not alter RVSP (32.4 ± 1.8; n = 9), but it substantially improved survival (93% vs. 57% DMSO). There were no differences between DMSO and PKT100 bleomycin mice in pulmonary inflammation or remodeling. However, RV hypertrophy was reduced in PKT100 mice. Bleomycin decreased echocardiographic surrogates of RV systolic performance, which were significantly improved with PKT100. Four genes involved in RV remodeling (RPSA, Rplp0, Add2, and Scn7a) were differentially expressed between DMSO and PKT100-treated groups. The novel P2X7R inhibitor, PKT100, attenuates RV hypertrophy and improves RV contractile function and survival in a mouse model of PH independently of effects on the pulmonary vasculature. PKT100 may improve ventricular response to increased afterload and merits further investigation into the potential role of P2X7R antagonists as direct RV-focused therapies in PH.NEW & NOTEWORTHY This study demonstrates the therapeutic potential for right-sided heart failure of a novel inhibitor of the P2X7 receptor (P2X7R). Inflammatory signaling and right ventricular function were improved in a mouse model of pulmonary fibrosis with secondary pulmonary hypertension when treated with this inhibitor. Importantly, survival was also improved, suggesting that this inhibitor, and other P2X7R antagonists, could be uniquely effective in right ventricle (RV)-targeted therapy in pulmonary hypertension. This addresses a major limitation of current treatment options, where the significant improvements in pulmonary pressures ultimately do not prevent mortality due to RV failure.

The year in review: advances in interventional cardiology in 2019

PURPOSE OF REVIEW

Major studies in interventional cardiology in 2019 have added substantial new evidence for pharmaco-invasive management of coronary artery disease. The review highlights the main findings of a selection of these trials and summarizes their impact on clinical practice.

RECENT FINDINGS

Recent randomized studies examining the efficacy of revascularization or medical treatment in stable ischemic heart disease (SIHD), treatment of acute coronary syndromes, emerging interventional devices, adjunctive pharmacotherapy, and intravascular imaging and physiology guidance have substantially advanced the evidenced-based knowledge in interventional cardiology.

SUMMARY

Patients with SIHD and at least moderate myocardial ischemia have similar event-free survival after an initial conservative strategy of optimal medical therapy versus an upfront invasive strategy. Quality of life and angina-free status are significantly improved with revascularization. Percutaneous coronary intervention (PCI) and coronary artery bypass grafting provide similar 5-year outcomes in patients with left main coronary artery disease and low or intermediate disease complexity. An initially conservative management is equally effective as an early invasive approach in patients with out-of-hospital cardiac arrest without ongoing ischemia. Patients with ST-segment elevation myocardial infarction and multivessel disease benefit from staged complete revascularization after primary PCI. Post-PCI, patients with atrial fibrillation requiring anticoagulation can safely and effectively be treated with P2Y12 inhibitor monotherapy without aspirin. Lastly, intravascular imaging guidance improves post-PCI outcomes, warranting increased use in clinical practice.

Intracoronary Optical Coherence Tomography 2018: Current Status and Future Directions

The advent of intravascular imaging has been a significant advancement in visualization of coronary arteries, particularly with optical coherence tomography (OCT) that allows for high-resolution imaging of intraluminal and transmural coronary structures. Accumulating data support a clinical role for OCT in a multitude of clinical scenarios, including assessing the natural history of atherosclerosis and modulating effects of therapies, mechanisms of acute coronary syndromes, mechanistic insights into the effects of novel interventional devices, and optimization of percutaneous coronary intervention. In this state-of-the-art review, we provide an overview of the published data on the clinical utility of OCT, highlighting the areas that need further investigation and the current barriers for further adoption of OCT in interventional cardiology practice.

The "Oculo-Appositional Reflex": Should Optical Coherence Tomography-Detected Stent Malapposition Be Corrected?

See Article by Im et al

Algorithmic Approach for Optical Coherence Tomography-Guided Stent Implantation During Percutaneous Coronary Intervention

Intravascular imaging plays a key role in optimizing outcomes for percutaneous coronary intervention (PCI). Optical coherence tomography (OCT) utilizes a user-friendly interface and provides high-resolution images. OCT can be used as part of daily practice in all stages of a coronary intervention: baseline lesion assessment, stent selection, and stent optimization. Incorporating a standardized, algorithmic approach when using OCT allows for precision PCI.

The NRF2 activator DH404 attenuates adverse ventricular remodeling post-myocardial infarction by modifying redox signalling

BACKGROUND

The novel synthetic triterpenoid, bardoxolone methyl, has the ability to upregulate cytoprotective proteins via induction of the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway. This makes it a promising therapeutic agent in disease states characterized by dysregulated oxidative signalling. We have examined the effect of a Nrf2 activator, dihydro-CDDO-trifluoroethyl amide (DH404), a derivative of bardoxolone methyl, on post-infarct cardiac remodeling in rats.

METHODS/RESULTS

DH404, administered from day 2 post myocardial infarction (MI: 30min transient ischemia followed by reperfusion) resulted in almost complete protection against adverse ventricular remodeling as assessed at day 28 (left ventricular end-systolic area: sham 0.14±0.01cm², MI vehicle 0.29±0.04cm² vs. MI DH404 0.18±0.02cm², P<0.05); infarct size (21.3±3.4% MI vehicle vs. 10.9±2.3% MI DH404, P<0.05) with associated benefits on systolic function (fractional shortening: sham 71.9±2.6%, MI vehicle 36.2±1.9% vs. MI DH404 58.6±4.0%, P<0.05). These structural and functional benefits were associated with lower myocardial expression of atrial natriuretic peptide (ANP, P<0.01 vs. MI vehicle), and decreased fibronectin (P<0.01 vs. MI vehicle) in DH404-treated MI rats at 28 days. MI increased glutathionylation of endothelial nitric oxide synthase (eNOS) in vitro - a molecular switch that uncouples the enzyme, increasing superoxide production and decreasing nitric oxide (NO) bioavailability. MI-induced eNOS glutathionylation was substantially ameliorated by DH404. An associated increase in glutaredoxin 1 (Grx1) co-immunoprecipitation with eNOS without a change in expression was mechanistically intriguing. Indeed, in parallel in vitro experiments, silencing of Grx1 abolished the protective effect of DH404 against Angiotensin II-induced eNOS uncoupling.

CONCLUSION

The bardoxolone derivative DH404 significantly attenuated cardiac remodeling post MI, at least in part, by re-coupling of eNOS and increasing the functional interaction of Grx1 with eNOS. This agent may have clinical benefits protecting against post MI cardiomyopathy.

Utility of near-infrared spectroscopy for detection of thin-cap neoatherosclerosis

Aims

Near-infrared spectroscopy (NIRS) has been employed to assess the composition of the atherosclerotic plaques in native coronary arteries. However, little is known about the detection of neoatherosclerosis by NIRS in in-stent restenosis (ISR). The aim of the study was to assess the relationship between the distribution of lipid determined by NIRS and morphology of ISR on optical coherence tomography (OCT).

Methods and results

We performed both NIRS and OCT in 39 drug-eluting stents with ISR. Values of lipid-core burden index (LCBI) derived by NIRS were compared with the OCT-derived thickness of the fibrous cap covering neoatherosclerotic lesions. A total of 22 (49%) in-stent neointimas were identified as lipid rich by both NIRS and OCT. There was good agreement between OCT and NIRS in identifying lipid within in-stent neointima (kappa = 0.60, 95% CI: 0.34-0.86). OCT identified thin-cap neoatheromas (TCNA) (<65 µm) in 12 stents (23%). The minimal cap thickness of in-stent neoatherosclerotic plaque measured by OCT correlated with the maxLCBI4mm (maximal LCBI per 4 mm) within the stent (r = -0.77, P< 0.01). Moreover, maxLCBI4mm was able to accurately predict TCNA with a cut-off value of >144.

Conclusion

NIRS correlates with OCT identification of lipids in stented vessels and is able to predict the presence of thin fibrous cap neoatheroma.

Zero-contrast percutaneous coronary intervention on calcified lesions facilitated by rotational atherectomy

Percutaneous coronary intervention (PCI) in patients with advanced chronic kidney disease (CKD) is challenging due to frequent presence of complex calcified lesions and the very high risk of contrast-induced nephropathy (CIN). We report a strategy of "zero contrast" PCI, guided by intravascular imaging and physiology, performed in three patients with advanced CKD in whom severe calcification necessitated rotational atherectomy (RA) to facilitate and optimize PCI. This approach resulted in safe and successful PCI while preserving renal function. © 2017 Wiley Periodicals, Inc.