Atrial giant cell myocarditis: a distinctive clinicopathologic entity.

BACKGROUND: Giant cell myocarditis (GCM) typically causes fulminant heart failure, arrhythmias, or heart block, necessitating aggressive immunosuppression, ventricular assist device insertion, or cardiac transplantation. We describe a novel variant of GCM, primarily involving the atria, that displays distinctive clinical features and follows a more benign course than ventricular GCM. METHODS AND RESULTS: We identified 6 patients (median age 67.5 years, 4 male) with atrial GCM in our pathology consultation practices from 2010 to 2012. Clinical history, imaging, and pathology materials were reviewed. Clinically, 4 patients had atrial fibrillation, 1 had acute heart failure, and 1 had incidental disease at autopsy. Among the 5 living patients, echocardiography revealed severe atrial dilatation (5 cases), mitral/tricuspid regurgitation (5), atrial mural thrombus (3), atrial wall thickening (2), and atrial hypokinesis (2). Ventricular function was preserved in all 5. Histological review of surgically resected atria showed giant cell and lymphocytic infiltrates, lymphocytic myocarditis-like foci, cardiomyocyte necrosis, and cardiomyocyte hypertrophy in all cases. Other features included interstitial fibrosis (5), poorly-formed granulomas (4), eosinophils (4), neutrophils (1), and vasculitis (1). Treatment consisted of steroids and cyclosporine (1), pacemaker placement for sick sinus syndrome (1), and supportive care (3). All 5 living patients returned to baseline exercise tolerance after 6 to 16 weeks of follow-up. CONCLUSIONS: Atrial GCM represents a distinct clinicopathologic entity with a more favorable prognosis than classic ventricular GCM. This disorder should be included in the differential diagnosis of atrial dilatation, particularly when associated with atrial wall thickening. The utility of immunomodulatory therapy for this condition remains unknown.

Comparative analysis of genome-wide association studies signals for lipids, diabetes, and coronary heart disease: Cardiovascular Biomarker Genetics Collaboration.

AIMS: To evaluate the associations of emergent genome-wide-association study-derived coronary heart disease (CHD)-associated single nucleotide polymorphisms (SNPs) with established and emerging risk factors, and the association of genome-wide-association study-derived lipid-associated SNPs with other risk factors and CHD events. METHODS AND RESULTS: Using two case-control studies, three cross-sectional, and seven prospective studies with up to 25 000 individuals and 5794 CHD events we evaluated associations of 34 genome-wide-association study-identified SNPs with CHD risk and 16 CHD-associated risk factors or biomarkers. The Ch9p21 SNPs rs1333049 (OR 1.17; 95% confidence limits 1.11-1.24) and rs10757274 (OR 1.17; 1.09-1.26), MIA3 rs17465637 (OR 1.10; 1.04-1.15), Ch2q36 rs2943634 (OR 1.08; 1.03-1.14), APC rs383830 (OR 1.10; 1.02, 1.18), MTHFD1L rs6922269 (OR 1.10; 1.03, 1.16), CXCL12 rs501120 (OR 1.12; 1.04, 1.20), and SMAD3 rs17228212 (OR 1.11; 1.05, 1.17) were all associated with CHD risk, but not with the CHD biomarkers and risk factors measured. Among the 20 blood lipid-related SNPs, LPL rs17411031 was associated with a lower risk of CHD (OR 0.91; 0.84-0.97), an increase in Apolipoprotein AI and HDL-cholesterol, and reduced triglycerides. SORT1 rs599839 was associated with CHD risk (OR 1.20; 1.15-1.26) as well as total- and LDL-cholesterol, and apolipoprotein B. ANGPTL3 rs12042319 was associated with CHD risk (OR 1.11; 1.03, 1.19), total- and LDL-cholesterol, triglycerides, and interleukin-6. CONCLUSION: Several SNPs predicting CHD events appear to involve pathways not currently indexed by the established or emerging risk factors; others involved changes in blood lipids including triglycerides or HDL-cholesterol as well as LDL-cholesterol. The overlapping association of SNPs with multiple risk factors and biomarkers supports the existence of shared points of regulation for these phenotypes.

A role of matrix metalloproteinase-8 in atherosclerosis.

RATIONALE: Atherosclerotic lesions express matrix metalloproteinase (MMP)8, which possesses proteolytic activity on matrix proteins particularly fibrillar collagens and on nonmatrix proteins such as angiotensin (Ang) I. OBJECTIVE: We studied whether MMP8 plays a role in atherogenesis. METHODS AND RESULTS: In atherosclerosis-prone apolipoprotein E-deficient mice, inactivating MMP8 resulted in a substantial reduction in atherosclerotic lesion formation. Immunohistochemical examinations showed that atherosclerotic lesions in MMP8-deficient mice had significantly fewer macrophages but increased collagen content. In line with results of in vitro assays showing that Ang I cleavage by MMP8 generated Ang II, MMP8 knockout mice had lower Ang II levels and lower blood pressure. In addition, we found that products of Ang I cleavage by MMP8 increased vascular cell adhesion molecule (VCAM)-1 expression and that MMP8-deficient mice had reduced VCAM-1 expression in atherosclerotic lesions. Intravital microscopy analysis showed that leukocyte rolling and adhesion on vascular endothelium was reduced in MMP8 knockout mice. Furthermore, we detected an association between MMP8 gene variation and extent of coronary atherosclerosis in patients with coronary artery disease. A relationship among MMP8 gene variation, plasma VCAM-1 level, and atherosclerosis progression was also observed in a population-based, prospective study. CONCLUSIONS: These results indicate that MMP8 is an important player in atherosclerosis.

Genetic Variation at the ADAMTS7 Locus is Associated With Reduced Severity of Coronary Artery Disease.

BACKGROUND: Genome-wide association studies identified ADAMTS7 as a risk locus for coronary artery disease (CAD). Functional studies suggest that ADAMTS7 may promote cellular processes in atherosclerosis. We sought to examine the association between genetic variation at ADAMTS7 and measures of atherosclerosis using histological, angiographic, and clinical outcomes data. METHODS AND RESULTS: The lead CAD-associated single-nucleotide polymorphism rs3825807 at the ADAMTS7 locus was genotyped. The G allele (reduced ADAMTS7 function) was associated with a smaller fibrous cap (P=0.017) and a smaller percentage area of α-actin (smooth muscle cell marker) in the intima (P=0.017), but was not associated with calcification or plaque thickness, following ex vivo immunohistochemistry analysis of human coronary plaques (n=50; mean age 72.2±11.3). In two independent cohorts (Southampton Atherosclerosis Study [n=1359; mean age 62.5±10.3; 70.1% men] and the Emory Cardiovascular Biobank [EmCAB; n=2684; mean age 63.8±11.3; 68.7% men]), the G allele was associated with 16% to 19% lower odds of obstructive CAD (Southampton Atherosclerosis Study: odds ratio, 0.81; 95% confidence interval, 0.67-0.98; EmCAB: odds ratio, 0.84; 95% confidence interval, 0.75-0.95) with similar effects for multivessel, left anterior descending, and proximal CAD. Furthermore, each copy of the G allele was associated with lower angiographic severity Gensini score (Southampton Atherosclerosis Study, P=0.026; EmCAB, P<0.001), lower Sullivan Extent score (Southampton Atherosclerosis Study, P=0.029; EmCAB, P<0.001), and a 23% lower risk of incident revascularization procedures (EmCAB: hazard ratio, 0.76; 95% confidence interval, 0.59-0.98). There were no associations with all-cause mortality or incident myocardial infarction. CONCLUSIONS: Genetic variation at the ADAMTS7 locus is associated with several complementary CAD phenotypes, supporting the emerging role of ADAMTS7 in atherosclerosis and may represent a potential drug target.

Total Center Percutaneous Coronary Intervention Volume and 30-Day Mortality: A Contemporary National Cohort Study of 427 467 Elective, Urgent, and Emergency Cases.

BACKGROUND: The relationship between procedural volume and prognosis after percutaneous coronary intervention (PCI) remains uncertain, with some studies finding in favor of an inverse association and some against. This UK study provides a contemporary reassessment in one of the few countries in the world with a nationally representative PCI registry. METHODS AND RESULTS: A nationwide cohort study was performed using the national British Cardiovascular Intervention Society registry. All adult patients undergoing PCI in 93 English and Welsh NHS hospitals between 2007 and 2013 were analyzed using hierarchical modeling with adjustment for patient risk. Of 427 467 procedures (22.0% primary PCI) in 93 hospitals, 30-day mortality was 1.9% (4.8% primary PCI). 87.1% of centers undertook between 200 and 2000 procedures annually. Case mix varied with center volume. In centers with 200 to 399 PCI cases per year, a smaller proportion were PCI for ST-segment-elevation myocardial infarction (8.4%) than in centers with 1500 to 1999 PCI cases per year (24.2%), but proportionally more were for ST-segment-elevation myocardial infarction with cardiogenic shock (8.4% versus 4.3%). For the overall PCI cohort, after risk adjustment, there was no significant evidence of worse, or better, outcomes in lower volume centers from our own study, or in combination with results from other studies. For primary PCI, there was also no evidence for increased or decreased mortality in lower volume centers. CONCLUSIONS: After adjustment for differences in case mix and clinical presentation, this study supports the conclusion of no trend for increased mortality in lower volume centers for PCI in the UK healthcare system. CLINICAL TRIAL REGISTRATION: https://www.clinicaltrials.gov. Unique identifier: NCT02184949.

Association between the chromosome 9p21 locus and angiographic coronary artery disease burden: a collaborative meta-analysis.

OBJECTIVES: This study sought to ascertain the relationship of 9p21 locus with: 1) angiographic coronary artery disease (CAD) burden; and 2) myocardial infarction (MI) in individuals with underlying CAD. BACKGROUND: Chromosome 9p21 variants have been robustly associated with coronary heart disease, but questions remain on the mechanism of risk, specifically whether the locus contributes to coronary atheroma burden or plaque instability. METHODS: We established a collaboration of 21 studies consisting of 33,673 subjects with information on both CAD (clinical or angiographic) and MI status along with 9p21 genotype. Tabular data are provided for each cohort on the presence and burden of angiographic CAD, MI cases with underlying CAD, and the diabetic status of all subjects. RESULTS: We first confirmed an association between 9p21 and CAD with angiographically defined cases and control subjects (pooled odds ratio [OR]: 1.31, 95% confidence interval [CI]: 1.20 to 1.43). Among subjects with angiographic CAD (n = 20,987), random-effects model identified an association with multivessel CAD, compared with those with single-vessel disease (OR: 1.10, 95% CI: 1.04 to 1.17)/copy of risk allele). Genotypic models showed an OR of 1.15, 95% CI: 1.04 to 1.26 for heterozygous carrier and OR: 1.23, 95% CI: 1.08 to 1.39 for homozygous carrier. Finally, there was no significant association between 9p21 and prevalent MI when both cases (n = 17,791) and control subjects (n = 15,882) had underlying CAD (OR: 0.99, 95% CI: 0.95 to 1.03)/risk allele. CONCLUSIONS: The 9p21 locus shows convincing association with greater burden of CAD but not with MI in the presence of underlying CAD. This adds further weight to the hypothesis that 9p21 locus primarily mediates an atherosclerotic phenotype.

Personalised antiplatelet therapy in stent thrombosis: observations from the Clopidogrel Resistance in Stent Thrombosis (CREST) registry.

OBJECTIVE: Previous studies have demonstrated significant heterogeneity in responses to antiplatelet therapy (APT), and high residual platelet reactivity is associated with the risk of ischaemic events, including stent thrombosis (ST). The prevalence of APT hyporesponsiveness in a 'real world' registry of ST patients and the feasibility of personalising APT are reported. PATIENTS AND SETTING: 39 consecutive patients admitted to a single regional cardiothoracic centre with definite ST were prospectively evaluated. INTERVENTIONS: Response to aspirin and clopidogrel was measured following discharge using short thrombelastography (TEG), a rapid, well validated near patient platelet function test. Treatment modification in hyporesponders comprised an increase in aspirin dose and/or changing clopidogrel to prasugrel or ticagrelor. Short TEG was repeated following treatment modification to ensure an adequate response had been achieved. RESULTS: 12 (31%) patients had an adequate response to both aspirin and clopidogrel, 16 (41%) were hyporesponsive to clopidogrel alone, one (3%) was hyporesponsive to aspirin alone and 10 (26%) were hyporesponsive to both aspirin and clopidogrel. Following treatment modification, an adequate response to aspirin and P2Y12 agent was achieved in 10 (91%) and 22 (85%) patients, respectively. None has presented with a further ST episode. CONCLUSIONS: There is a high prevalence of hyporesponsiveness to APT in patients with ST. Improved APT efficacy can be achieved by tailored therapy. Short TEG is a plausible platelet function test that can be used to deliver point of care personalised APT.

ADAM33 expression in atherosclerotic lesions and relationship of ADAM33 gene variation with atherosclerosis.

A-disintegrin-and-metalloproteinase-domains (ADAMs) are membrane-anchored glycoproteins involved in cell adhesion, cell migration and proteolysis. ADAM15 has been implicated in atherosclerosis, with an effect on vascular smooth muscle cell migration. We investigated whether ADAM33, which is evolutionally closely related to ADAM15, was expressed in atheromas and whether it had an effect on vascular smooth muscle migration. We also tested whether ADAM33 gene variation had an influence on the extent of atherosclerosis in patients with coronary artery disease. Immunohistochemical analyses showed that ADAM33 was expressed in smooth muscle cells in the arterial wall and that the expression was increased in smooth muscle cells in atheromas. ADAM33 immunostaining on inflammatory cells in atheromas was also observed. Primary vascular smooth muscle cells in culture were also found to express ADAM33. Boyden chamber assays showed that a neutralising antibody against ADAM33 increased the ability of arterial smooth muscle cells to migrate through a reconstituted basement membrane, suggesting that ADAM33 has an inhibitory effect on vascular smooth muscle migration. Moreover, we detected an association between ADAM33 genotype and the extent of atherosclerosis in a large cohort of coronary artery disease patients. These findings suggest that ADAM33 is implicated in the pathogenesis of atherosclerosis.

The evaluation of real-time 3-dimensional transthoracic echocardiography for the preoperative functional assessment of patients with mitral valve prolapse: a comparison with 2-dimensional transesophageal echocardiography.

OBJECTIVE: We sought to compare the feasibility and accuracy of transthoracic real-time 3-dimensional echocardiography (RT-3DE) with transesophageal echocardiography (TEE) for the preoperative functional assessment of patients with mitral valve prolapse. METHODS: In 44 patients with severe mitral regurgitation caused by type 2 valve dysfunction, TEE and RT-3DE were performed 24 hours before surgery and analyzed by two separate observers. TEE and RT-3DE images were acquired digitally and stored for offline analysis. The echocardiographic results were validated intraoperatively. RESULTS: Five patients did not have image quality suitable for analysis with RT-3DE and were excluded from analysis, leaving a sample size of 39. In total, 54 of 334 analyzed mitral valve segments were diseased. Prolapse of a single mitral valve segment was present in 25 patients and 14 patients had complex disease involving two or more segments. Sensitivity, specificity, and accuracy for TEE in identification of diseased segments were 94%, 100%, and 96%, respectively. The same values for RT-3DE were 91%, 100%, and 94%, respectively. The differences were not statistically significant. Accuracies were not significantly different according to segment location. Interobserver agreement was 92% for TEE and 88% for RT-3DE (P = nonsignificant). CONCLUSIONS: RT-3DE is feasible with comparative accuracy to TEE for precise anatomic localization of prolapsing mitral valve segments. However, the technique is limited by poor image quality in 11% of patients.

Acute thrombosis of a prosthetic mitral valve: a lesson in anticoagulation.

Prosthetic heart valve thrombosis is a potentially life-threatening complication of low anticoagulation. We present a case of acute prosthetic mitral valve thrombosis in a patient whose anticoagulation was inadequate after phenindione was changed to low molecular weight heparin. We discuss the diagnosis and treatment of this condition and highlight the danger of long-term low molecular weight heparin use in patients with prosthetic heart valves, especially those in the mitral position. We review the current guidelines for anticoagulation of prosthetic heart valves and discuss potential treatment options if adequate anticoagulation is not achieved by oral anticoagulant alone.

Functional polymorphism in ABCA1 influences age of symptom onset in coronary artery disease patients.

ATP-binding-cassette-transporter-A1 (ABCA1) plays a pivotal role in intracellular cholesterol removal, exerting a protective effect against atherosclerosis. ABCA1 gene severe mutations underlie Tangier disease, a rare Mendelian disorder that can lead to premature coronary artery disease (CAD), with age of CAD onset being two decades earlier in mutant homozygotes and one decade earlier in heterozygotes than in mutation non-carriers. It is unknown whether common polymorphisms in ABCA1 could influence age of symptom onset of CAD in the general population. We examined common promoter and non-synonymous coding polymorphisms in relation to age of symptom onset in a group of CAD patients (n = 1164), and also carried out in vitro assays to test effects of the promoter variations on ABCA1 promoter transcriptional activity and effects of the coding variations on ABCA1 function in mediating cellular cholesterol efflux. Age of symptom onset was found to be associated with the promoter - 407G > C polymorphism, being 2.82 years higher in C allele homozygotes than in G allele homozygotes and intermediate in heterozygotes (61.54, 59.79 and 58.72 years, respectively; P = 0.002). In agreement, patients carrying ABCA1 haplotypes containing the -407C allele had higher age of symptom onset. Patients of the G/G or G/C genotype of the -407G > C polymorphism had significant coronary artery stenosis (>75%) at a younger age than those of the C/C genotype (P = 0.003). Reporter gene assays showed that ABCA1 haplotypes bearing the -407C allele had higher promoter activity than haplotypes with the -407G allele. Functional analyses of the coding polymorphisms showed an effect of the V825I substitution on ABCA1 function, with the 825I variant having higher activity in mediating cholesterol efflux than the wild-type (825V). A trend towards higher symptom onset age in 825I allele carriers was observed. The data indicate an influence of common ABCA1 functional polymorphisms on age of symptom onset in CAD patients.

Mutation scanning by meltMADGE: validations using BRCA1 and LDLR, and demonstration of the potential to identify severe, moderate, silent, rare, and paucimorphic mutations in the general population.

We have developed a mutation-scanning approach suitable for whole population screening for unknown mutations. The method, meltMADGE, combines thermal ramp electrophoresis with MADGE to achieve suitable cost efficiency and throughput. The sensitivity was tested in blind trials using 54 amplicons representing the BRCA1 coding region and a panel of 94 unrelated family breast cancer risk consultands previously screened in a clinical diagnostic laboratory. All 10 common polymorphisms, 15/15 previously identified disease-causing mutations, and three previously untested single base changes were identified. Assays of LDLR exons 3 and 8 were validated in 460 familial hypercholesteremics and detected 8/9 known variants. We then applied the exon 3 assay in several DNA banks representing approximately 8000 subjects with known cholesterol values and applied both assays in one DNA bank (n = 3600). In exon 3 we identified one previously reported moderate mutation, P84S (n = 1), also associated with moderate hypercholesteremia in this subject; an unreported silent variant, N76N (n = 1); and known severe hypercholesteremia splice mutation 313+1G-->A (n = 2). Around exon 8 we identified a paucimorphism (n = 35) at the splice site 1061-8T-->C (known to be in complete linkage disequilibrium with T705I) and unreported sequence variants 1186+11G-->A (n = 1) and D335N G-->A (n = 1). The cholesterol value for D335N was on the 96.2 percentile and for T705I, 2/35 carriers were above the 99th percentile. Thus, variants with predicted severe, moderate, and no effect were identified at the population level. In contrast with case collections, CpG mutations predominated. MeltMADGE will enable definition of the full population spectrum of rare, paucimorphic, severe, moderate (forme fruste), and silent mutations and effects.