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Topic Importance: Long COVID may occur in at least 10% of patients recovering from SARS-CoV-2 infection and often is associated with debilitating symptoms. Among the organ systems that might be involved in its pathogenesis, the respiratory and cardiovascular systems may be central to common symptoms seen in survivors of COVID-19, including fatigue, dyspnea, chest pain, cough, and exercise intolerance. Understand the exact symptomatology, causes, and effects of long COVID on the heart and lungs may help us to discover new therapies. To that end, the National Institutes of Health is sponsoring a national study population of diverse volunteers to support large-scale studies on the long-term effects of COVID-19., Review Findings: The National Institutes of Health Researching COVID to Enhance Recovery (RECOVER) initiative currently is recruiting participants in the United States to answer critical questions about long COVID. The study comprises adult and pediatric cohorts as well as an electronic health record cohort. Based on symptoms, individuals undergo prespecified medical testing to understand whether abnormalities can be detected and are followed up longitudinally. Herein, we outline current understanding of the clinical symptoms and pathophysiologic features of long COVID with respect to the cardiopulmonary system in adults and children and then determine how the clinical, electronic health record, and autopsy cohorts of the RECOVER initiative will attempt to answer the most pressing questions surrounding the long-term effects of COVID-19., Summary: Data generated from the RECOVER initiative will provide guidance about missing gaps in our knowledge about long COVID and how they might be filled by data gathered through the RECOVER initiative., Competing Interests: Financial/Nonfinancial Disclosures None declared., (Copyright © 2024 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Importance: Unexplained sudden cardiac death (SCD) describes SCD with no cause identified. Genetic testing helps to diagnose inherited cardiac diseases in unexplained SCD; however, the associations between pathogenic or likely pathogenic (P/LP) variants of inherited cardiomyopathies (CMs) and arrhythmia syndromes and the risk of unexplained SCD in both White and African American adults living the United States has never been systematically examined., Objective: To investigate cases of unexplained SCD to determine the frequency of P/LP genetic variants of inherited CMs and arrhythmia syndromes., Design, Setting, and Participants: This genetic association study included 683 African American and White adults who died of unexplained SCD and were included in an autopsy registry. Overall, 413 individuals had DNA of acceptable quality for genetic sequencing. Data were collected from January 1995 to December 2015. A total of 30 CM genes and 38 arrhythmia genes were sequenced, and variants in these genes, curated as P/LP, were examined to study their frequency. Data analysis was performed from June 2018 to March 2021., Main Outcomes and Measures: The frequency of P/LP variants for CM or arrhythmia in individuals with unexplained SCD., Results: The median (interquartile range) age at death of the 413 included individuals was 41 (29-48) years, 259 (62.7%) were men, and 208 (50.4%) were African American adults. A total of 76 patients (18.4%) with unexplained SCD carried variants considered P/LP for CM and arrhythmia genes. In total, 52 patients (12.6%) had 49 P/LP variants for CM, 22 (5.3%) carried 23 P/LP variants for arrhythmia, and 2 (0.5%) had P/LP variants for both CM and arrhythmia. Overall, 41 P/LP variants for hypertrophic CM were found in 45 patients (10.9%), 9 P/LP variants for dilated CM were found in 11 patients (2.7%), and 10 P/LP variants for long QT syndrome were found in 11 patients (2.7%). No significant difference was found in clinical and heart characteristics between individuals with or without P/LP variants. African American and White patients were equally likely to harbor P/LP variants., Conclusions and Relevance: In this large genetic association study of community cases of unexplained SCD, nearly 20% of patients carried P/LP variants, suggesting that genetics may contribute to a significant number of cases of unexplained SCD. Our findings regarding both the association of unexplained SCD with CM genes and race-specific genetic variants suggest new avenues of study for this poorly understood entity.

Background: Transcatheter aortic valve replacement (TAVR) has recently become an alternative to surgical aortic valve replacement for patients with severe aortic stenosis. However, paravalvular leaks, possible leaflet thrombosis, and device durability following TAVR remain unresolved issues., Methods and Results: We conducted the first systematic microscopic and macroscopic pathologic analysis of self-expanding CoreValve transcatheter aortic valves removed at autopsy or surgically from the U.S. pivotal trial of extreme- and high-risk patients. Implants were evaluated for histopathologic changes in the valve frame and leaflets. Thrombus/neointima on the leaflets was graded depending on the leaflet thickness and the extent of leaflet involvement. Inflammation, calcification, and structural integrity were also assessed. A total of 21 cases (median age 86.0 years [IQR, 79.0-91.0]), with median duration of implant duration of 17.0 days ranged from 0 to 503 days were evaluated. No valve frame fracture was observed and severe paravalvular gaps were uncommon. Inflammation and thrombus in the valve frame was minimal, but neointimal growth increased overtime. Symptomatic valve thrombosis was observed in one case (5%) and subclinical moderate leaflet thrombus was observed in four additional cases (19%). Inflammation of the leaflets was mild, while structural changes were minimal, and one case had infective endocarditis. Pannus or leaflet calcification were not observed., Conclusions: This first systematic macroscopic and microscopic pathologic analysis of self-expanding transcatheter aortic valves demonstrates favorable short-term pathologic findings. However, our finding of subclinical leaflet thrombus formation confirms prior observations and warrants further investigation., (© 2017 Wiley Periodicals, Inc.)

Plaque rupture, usually of a precursor lesion known as a 'vulnerable plaque' or 'thin-cap fibroatheroma', is the leading cause of thrombosis. Less-frequent aetiologies of coronary thrombosis are erosion, observed with greatest incidence in women aged <50 years, and eruptive calcified nodules, which are occasionally identified in older individuals. Various treatments for patients with coronary artery disease, such as CABG surgery and interventional therapies, have led to accelerated atherosclerosis. These processes occur within months to years, compared with the decades that it generally takes for native disease to develop. Morphological identifiers of accelerated atherosclerosis include macrophage-derived foam cells, intraplaque haemorrhage, and thin fibrous cap. Foam-cell infiltration can be observed within 1 year of a saphenous vein graft implantation, with subsequent necrotic core formation and rupture ensuing after 7 years in over one-third of patients. Neoatherosclerosis occurs early and with greater prevalence in drug-eluting stents than in bare-metal stents and, although rare, complications of late stent thrombosis from rupture are associated with high mortality. Comparison of lesion progression in native atherosclerotic disease, atherosclerosis in saphenous vein grafts, and in-stent neoatherosclerosis provides insight into the pathogenesis of atheroma formation in natural and iatrogenic settings.

Objectives: The study interrogated an autopsy registry to investigate the histopathologic features of early stent thrombosis (ST) in patients presenting with acute coronary syndrome (ACS)., Background: The occurrence of early ST following percutaneous coronary intervention (PCI) for ACS remains a clinical problem despite advances in stent technology in both bare-metal and drug-eluting stents., Methods: Sixty-seven stented coronary lesions from 59 patients who presented with ACS and died within 30 days were included. Stented segments were cross sectioned at 3 to 4 mm intervals and evaluated by light microscopy, and morphometric analysis was performed., Results: Early ST (<30 days of PCI) was identified in 34 (58%) of the 59 patients. Early ST was dependent on the underlying plaque morphology and underlying thrombus burden: presence of necrotic core prolapse was more frequent in thrombosed lesions compared with patent lesions (70% vs. 43%, p = 0.045) and maximal underlying thrombus thickness was significantly greater in thrombosed versus patent lesions. All 3 patients with false lumen stenting had ST. Detailed analysis revealed that the percent of necrotic core prolapse, medial tear, or incomplete apposition was significantly greater in the early ST compared with patent group (28% vs.11%, p < 0.001; 27% vs. 15% p = 0.004; and 34% vs. 18% p = 0.008, respectively). Multivariate analysis revealed that maximal depth of strut penetration, % strut with medial tear, and % struts with incomplete apposition were the primary indicators of early ST., Conclusions: The current autopsy study highlights the impact of thrombus burden and suboptimal stent implantation in unstable lesions as a trigger of early ST, suggesting that improvement in implantation technique and refinement of stent design may improve clinical outcomes of ACS patients., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to validate the sensitivity and specificity of the Academic Research Consortium's (ARC) classification of stent thrombosis., Background: Classification of stent thrombosis according to ARC criteria has become widely accepted. The criteria have not been validated against an autopsy standard., Methods: An autopsy registry of 139 subjects with prior coronary stenting underwent detailed histopathological analysis to assess for stent thrombosis. Based on clinical data only, cases were adjudicated according to ARC stent thrombosis criteria, including a proposed modification of the possible classification to include death beyond 30 days due only to sudden death or acute ischemia., Results: Autopsy results confirmed 51 cases as positive and 88 as negative for stent thrombosis. Clinical adjudication classified 105 cases as definite (10), probable (31), or possible (64) ARC stent thrombosis. Specificity was high for definite (99%) and definite plus probable (83%) criteria, but sensitivity was poor at 18% and 51%, respectively. Including the possible cases improved sensitivity to 92% but reduced specificity to 34% (58 false positives). The modified possible criteria eliminated 13 false positive cases (specificity = 49%) and was the best approximation of a hypothetical gold standard in a sensitivity analysis if late death represented at least 20% of all stent thrombosis cases., Conclusions: In a selected autopsy sample, restricting ARC stent thrombosis to definite or definite plus probable criteria results in substantial under-reporting of confirmed cases. Inclusion of a modified possible classification may provide the best estimate of late and very late stent thrombosis rates., (Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to perform pathologic assessment on stent fracture., Background: Clinically, stent fracture has been reported in 1% to 2% of patients after drug-eluting stent (DES) implantation., Methods: High-contrast film-based radiographs of 177 consecutive lesions from the CVPath DES autopsy registry were reviewed. Stent fracture was graded as I (single-strut fracture), II (> or =2 struts), III (> or =2 struts with deformation), IV (with transection without gap), and V (with transection causing gap in stent segment). The incidence of adverse pathologic findings (thrombosis and restenosis) was assessed histologically., Results: Stent fracture was documented in 51 lesions (29%; grade I = 10, II = 14, III = 12, IV = 6, and V = 9). Lesions with stent fracture had longer duration after implantation (172 days [interquartile range (IQR) 31 to 630 days] vs. 44 days [IQR 7 to 270 days], p = 0.004), a higher rate of Cypher (Cordis Corp., Miami Lakes, Florida) stent usage (63% vs. 36%, p = 0.001), longer stent length (30.0 mm [IQR 22.0 to 40.0 mm] vs. 20.0 mm [IQR 14.0 to 27.3 mm], p < 0.0001), and a higher rate of overlapping stents (45% vs. 22%, p = 0.003). Although fracture with grade I to IV did not have significant impact on the occurrence of adverse pathologic findings such as thrombosis and restenosis, 67% of the grade V fracture lesions were associated with adverse pathologic findings at fracture sites. Longer stent length, use of Cypher, and longer duration of implant were identified as independent risk factors of stent fracture by logistic regression analysis., Conclusions: The incidence of stent fracture was 29% lesions at autopsy, which is much higher than clinically reported. A high rate of adverse pathologic findings was observed in lesions with grade V stent fracture, whereas fracture with grade I to IV did not have a significant impact on the pathological outcome.

After pivotal clinical trials, drug-eluting stents (DES) are now considered the standard of care for the management of acute coronary syndrome. However, late stent thrombosis has emerged as a major concern. Preclinical testing is an important regulatory process that determines the safety and efficacy of devices prior to human clinical trials. Histopathologic analysis following placement of DES has typically been performed in porcine coronary artery models to ensure safety in these devices. The recently issued consensus report from the US FDA, for the approval of DES recommends the use of the porcine model for the safety assessment of these devices in the vascular bed for which they are intended. Other models are also recommended, as vascular responses to stents are much slower in man than in animals, and no animal truly elicits the response seen in humans. The rabbit iliac artery can provide further data, especially regarding endothelialization, which is slower in the rabbit model than in the porcine model. Furthermore, inflammation is not as extensive in the rabbit and may thus be a closer model of humans than the porcine models. The FDA recognizes that it may be more appropriate to test these devices in atherosclerosis. The choice of animal model may mask the serious drawbacks of the devices; therefore, we suggest the use of both models to understand the healing following DES implantation, with emphasis on endothelialization, inflammation and neointimal formation and, whenever possible, to complement the observations in the environment of atherosclerosis.