Kimberly A. Skelding

Bone Marrow–Derived Cardiomyocytes Are Present in Adult Human Heart A Study of Gender-Mismatched Bone Marrow Transplantation Patients

Background—Recent studies have identified cardiomyocytes of extracardiac origin in transplanted human hearts, but the exact origin of these myocyte progenitors is currently unknown. Methods and Results—Hearts of female subjects (n=4) who had undergone sex-mismatched bone marrow transplantation (BMT) were recovered at autopsy and analyzed for the presence of Y chromosome–positive cardiomyocytes. Four female gender-matched BMT subjects served as controls. Fluorescence in situ hybridization (FISH) for the Y chromosome was performed on paraffin-embedded sections to identify cells of bone marrow origin with concomitant immunofluorescent labeling for &agr;-sarcomeric actin to identify cardiomyocytes. A total of 160 000 cardiomyocyte nuclei were analyzed approximating 20 000 nuclei per patient. The mean percentage of Y chromosome–positive cardiomyocytes in patients with sex-mismatched BMT was 0.23±0.06%. Not a single Y chromosome–positive cardiomyocyte was identified in any of the control patients. Immunofluorescent costaining for laminin and chromosomal ploidy analysis with FISH showed no evidence of either pseudonuclei or cell fusion in any of the chimeric cardiac myocytes identified. Conclusions—These data establish for the first time human bone marrow as a source of extracardiac progenitor cells capable of de novo cardiomyocyte formation.

Bivalirudin versus Unfractionated Heparin during Percutaneous Coronary Intervention

BACKGROUND Whether bivalirudin is superior to unfractionated heparin in patients with stable or unstable angina who undergo percutaneous coronary intervention (PCI) after pretreatment with clopidogrel is unknown. METHODS We enrolled 4570 patients with stable or unstable angina (with normal levels of troponin T and creatine kinase MB) who were undergoing PCI after pretreatment with a 600-mg dose of clopidogrel at least 2 hours before the procedure; 2289 patients were randomly assigned in a double-blind manner to receive bivalirudin, and 2281 to receive unfractionated heparin. The primary end point was the composite of death, myocardial infarction, urgent target-vessel revascularization due to myocardial ischemia within 30 days after randomization, or major bleeding during the index hospitalization (with a net clinical benefit defined as a reduction in the incidence of the end point). The secondary end point was the composite of death, myocardial infarction, or urgent target-vessel revascularization. RESULTS The incidence of the primary end point was 8.3% (190 patients) in the bivalirudin group as compared with 8.7% (199 patients) in the unfractionated-heparin group (relative risk, 0.94; 95% confidence interval [CI], 0.77 to 1.15; P=0.57). The secondary end point occurred in 134 patients (5.9%) in the bivalirudin group and 115 patients (5.0%) in the unfractionated-heparin group (relative risk, 1.16; 95% CI, 0.91 to 1.49; P=0.23). The incidence of major bleeding was 3.1% (70 patients) in the bivalirudin group and 4.6% (104 patients) in the unfractionated-heparin group (relative risk, 0.66; 95% CI, 0.49 to 0.90; P=0.008). CONCLUSIONS In patients with stable and unstable angina who underwent PCI after pretreatment with clopidogrel, bivalirudin did not provide a net clinical benefit (i.e., it did not reduce the incidence of the composite end point of death, myocardial infarction, urgent target-vessel revascularization, or major bleeding) as compared with unfractionated heparin, but it did significantly reduce the incidence of major bleeding. (ClinicalTrials.gov number, NCT00262054.)

Transradial arterial access for coronary and peripheral procedures: executive summary by the Transradial Committee of the SCAI.

In response to growing U.S. interest, the Society for Coronary Angiography and Interventions recently formed a Transradial Committee whose purpose is to examine the utility, utilization, and training considerations related to transradial access for percutaneous coronary and peripheral procedures. With international partnership, the committee has composed a comprehensive overview of this subject presented herewith.

Best practices for transradial angiography and intervention: a consensus statement from the society for cardiovascular angiography and intervention's transradial working group.

Duke University Medical Center, Durham, North Carolina Stanford University Medical Center, Palo Alto, California Penn State Hershey Medical Center, Hershey, Pennsylvania Brigham and Women’s Hospital, Boston, Massachusetts Mayo Clinic, Rochester, Minnesota University of Illinois at Chicago/Jesse Brown VA Medical Center, Chicago, Illinois First Coast Heart and Vascular Center, Jacksonville, Florida G.V. (Sonny) Montgomery VA Medical CenterJackson, Mississippi. Stern Cardiovascular Foundation, Memphis, Tennessee Reid Heart Center at FirstHealth of the Carolinas, Pinehurst, North Carolina Deborah Heart & Lung Institute, Browns Mills, New Jersey Duke University Medical Center, Durham, North Carolina Lahey Clinic, Burlington, Massachusetts Geisinger Medical Center, Danville, Pennsylvania Apex Heart Institute, Seth N.H.L. Municipal Medical College, Ahmedabad, Gujarat, India The Wright Center for Graduate Medical Education, The Commonwealth Medical College, Scranton, Pennsylvania

Distribution and clinical impact of functional variants in 50,726 whole-exome sequences from the DiscovEHR study

Unleashing the power of precision medicine Precision medicine promises the ability to identify risks and treat patients on the basis of pathogenic genetic variation. Two studies combined exome sequencing results for over 50,000 people with their electronic health records. Dewey et al. found that ∼3.5% of individuals in their cohort had clinically actionable genetic variants. Many of these variants affected blood lipid levels that could influence cardiovascular health. Abul-Husn et al. extended these findings to investigate the genetics and treatment of familial hypercholesterolemia, a risk factor for cardiovascular disease, within their patient pool. Genetic screening helped identify at-risk patients who could benefit from increased treatment. Science, this issue p. 10.1126/science.aaf6814, p. 10.1126/science.aaf7000 More than 50,000 exomes, coupled with electronic health records, inform on medically relevant genetic variants. INTRODUCTION Large-scale genetic studies of integrated health care populations, with phenotypic data captured natively in the documentation of clinical care, have the potential to unveil genetic associations that point the way to new biology and therapeutic targets. This setting also represents an ideal test bed for the implementation of genomics in routine clinical care in service of precision medicine. RATIONALE The DiscovEHR collaboration between the Regeneron Genetics Center and Geisinger Health System aims to catalyze genomic discovery and precision medicine by coupling high-throughput exome sequencing to longitudinal electronic health records (EHRs) of participants in Geisinger’s MyCode Community Health Initiative. Here, we describe initial insights from whole-exome sequencing of 50,726 adult participants of predominantly European ancestry using clinical phenotypes derived from EHRs. RESULTS The median duration of EHR data associated with sequenced participants was 14 years, with a median of 87 clinical encounters, 687 laboratory tests, and seven procedures per participant. Forty-eight percent of sequenced individuals had one or more first- or second-degree relatives in the sample, and genome-wide autozygosity was similar to other outbred European populations. We found ~4.2 million single-nucleotide variants and insertion/deletion events, of which ~176,000 are predicted to result in loss of gene function (LoF). The overwhelming majority of these genetic variants occurred at a minor allele frequency of ≤1%, and more than half were singletons. Each participant harbored a median of 21 rare predicted LoFs. At this sample size, ~92% of sequenced genes, including genes that encode existing drug targets or confer risk for highly penetrant genetic diseases, harbor rare heterozygous predicted LoF variants. About 7% of sequenced genes contained rare homozygous predicted LoF variants in at least one individual. Linking these data to EHR-derived laboratory phenotypes revealed consequences of partial or complete LoF in humans. Among these were previously unidentified associations between predicted LoFs in CSF2RB and basophil and eosinophil counts, and EGLN1-associated erythrocytosis segregating in genetically identified family networks. Using predicted LoFs as a model for drug target antagonism, we found associations supporting the majority of therapeutic targets for lipid lowering. To highlight the opportunity for genotype-phenotype association discovery, we performed exome-wide association analyses of EHR-derived lipid values, newly implicating rare predicted LoFs, and deleterious missense variants in G6PC in association with triglyceride levels. In a survey of 76 clinically actionable disease-associated genes, we estimated that 3.5% of individuals harbor pathogenic or likely pathogenic variants that meet criteria for clinical action. Review of the EHR uncovered findings associated with the monogenic condition in ~65% of pathogenic variant carriers’ medical records. CONCLUSION The findings reported here demonstrate the value of large-scale sequencing in an integrated health system population, add to the knowledge base regarding the phenotypic consequences of human genetic variation, and illustrate the challenges and promise of genomic medicine implementation. DiscovEHR provides a blueprint for large-scale precision medicine initiatives and genomics-guided therapeutic target discovery. Therapeutic target validation and genomic medicine in DiscovEHR. (A) Associations between predicted LoF variants in lipid drug target genes and lipid levels. Boxes correspond to effect size, given as the absolute value of effect, in SD units; whiskers denote 95% confidence intervals for effect. The size of the box is proportional to the logarithm (base 10) of predicted LoF carriers. (B and C) Prevalence and expressivity of clinically actionable genetic variants in 76 disease genes, according to EHR data. G76, Geisinger-76. The DiscovEHR collaboration between the Regeneron Genetics Center and Geisinger Health System couples high-throughput sequencing to an integrated health care system using longitudinal electronic health records (EHRs). We sequenced the exomes of 50,726 adult participants in the DiscovEHR study to identify ~4.2 million rare single-nucleotide variants and insertion/deletion events, of which ~176,000 are predicted to result in a loss of gene function. Linking these data to EHR-derived clinical phenotypes, we find clinical associations supporting therapeutic targets, including genes encoding drug targets for lipid lowering, and identify previously unidentified rare alleles associated with lipid levels and other blood level traits. About 3.5% of individuals harbor deleterious variants in 76 clinically actionable genes. The DiscovEHR data set provides a blueprint for large-scale precision medicine initiatives and genomics-guided therapeutic discovery.

Door-to-Balloon Times Under 90 Min Can Be Routinely Achieved for Patients Transferred for ST-Segment Elevation Myocardial Infarction Percutaneous Coronary Intervention in a Rural Setting

OBJECTIVES The purpose of this study was to demonstrate the feasibility of routine transfer of ST-segment elevation myocardial infarction (STEMI) patients to achieve percutaneous coronary intervention (PCI) in less than 90 min from presentation. BACKGROUND Many PCI hospitals have achieved routine door-to-balloon times under 90 min for patients with STEMI presenting directly to the hospital. However, few patients transferred from a non-PCI center undergo PCI within 90 min of presentation. METHODS Our rural PCI hospital implemented a program in 2005 for rapid triage, transfer, and treatment of STEMI patients and made additional improvements in 2006 and 2007. Intervals between milestones in the STEMI triage/transfer/treatment process were assessed before and after implementation of the program. RESULTS During the 5-year study period, 676 patients with 687 STEMIs were transferred from 19 community hospitals and underwent PCI. Median door-to-balloon time decreased from 189 min to 88 min (p < 0.001). The time intervals reflecting efficiency of the referring hospitals, transfer services, and PCI hospital all significantly improved. In 2008, median door-to-balloon times were <90 min for 6 of the 7 most frequently referring hospitals. Delays during off-hours presentation in 2004 were abolished after the program was implemented in 2005. In-hospital mortality decreased from 6% before to 3% after implementation of the program. In multivariate modeling, presentation before initiation of the STEMI program predicted increased risk of in-hospital mortality (odds ratio: 3.74, 95% confidence interval: 1.22 to 11.51, p = 0.021). CONCLUSIONS A program of rapid triage, transfer, and treatment of STEMI patients presenting to non-PCI hospitals can reduce in-hospital mortality and produce progressive improvements in door-to-balloon time such that median door-to-balloon times under 90 min are feasible.

Integrin Profile and In Vivo Homing of Human Smooth Muscle Progenitor Cells

Background—Recently, we identified circulating smooth muscle progenitor cells (SPCs) in human peripheral blood. The integrin profile of such progenitors is currently unknown and may affect their in vivo homing characteristics. In this study, we determined the integrin profile of vascular progenitors and SPC adhesion to extracellular matrix (ECM) proteins in vitro and in vivo. Methods and Results—SPCs and endothelial progenitor cells (EPCs) were isolated from peripheral blood of healthy human subjects, and expression of surface integrins and adhesion to several vascular ECM proteins were determined. Homing of SPCs in vivo to specific ECM protein was determined by intracoronary infusion of fluorescent SPCs into porcine coronary arteries containing a fibronectin-coated mesh stent. SPCs had high expression of &bgr;1 integrin, moderate expression of &agr;1, low levels of &agr;v&bgr;3, and did not express &agr;v&bgr;5, &bgr;2, &agr;2&bgr;1, or &agr;4&bgr;1 integrins. In contrast, EPCs had high expression of &agr;2&bgr;1, &agr;v&bgr;3, &agr;v&bgr;5, &bgr;1, and &agr;1 and minimal expression of &agr;4&bgr;1. Moreover, SPCs showed increased adherence to fibronectin and collagen type I compared with vitronectin, consistent with their integrin profile, and demonstrated a similar degree of in vivo attachment to fibronectin-coated mesh. Conclusions—These data for the first time show a spectrum of integrin expression on vascular progenitors and suggest the potential importance of integrins in mediating adherence of SPCs to specific ECM both in vitro and in vivo.

SCAI consensus document on occupational radiation exposure to the pregnant cardiologist and technical personnel

Concerns regarding radiation exposure and its effects during pregnancy are often quoted as an important barrier preventing many women from pursuing a career in Interventional Cardiology. Finding the true risk of radiation exposure from performing cardiac catheterization procedures can be challenging and guidelines for pregnancy exposure have been inadequate. The Women in Innovations group of Cardiologists with endorsement of the Society for Cardiovascular Angiography and Interventions aim to provide guidance in this publication by describing the risk of radiation exposure to pregnant physicians and cardiac catheterization personnel, to educate on appropriate radiation monitoring and to encourage mechanisms to reduce radiation exposure. Current data do not suggest a significant increased risk to the fetus of pregnant women in the cardiac catheterization laboratory and thus do not justify precluding pregnant physicians from performing procedures in the cardiac catheterization laboratory. However, radiation exposure among pregnant physicians should be properly monitored and adequate radiation safety measures are still warranted.

Rationale and study design of the CardioGene Study: genomics of in-stent restenosis

BACKGROUND AND AIMS in-stent restenosis is a major limitation of stent therapy for atherosclerosis coronary artery disease. The CardioGene Study is an ongoing study of restenosis in bare mental stents (BMS) for the treatment of coronary artery disease. The overall goal is to understand the genetic determinants of the responses to vascular injury that result in the development of restenosis in some patients but not in others. Gene expression profiling at transcriptional and translational levels provides global assessment of gene activity after vascular injury and mechanistic insight. Furthermore, the delineation of genetic biomarkers would be of value in the clinical setting of risk-stratify patients prior to stent therapy. Prospective risk stratification would allow for the rational selection of specialized treatments against the development of in-stent restenosis (ISR), such as drug-eluting stents. SETTING Patients are enrolled at two sites in the US with high-volume cardiac catheterization facilities: the William Beaumont Hospital in Royal Oak, MI, USA, and the Mayo Clinic in Rochester, MN, USA. STUDY DESIGN Two complementary study designs are used to understand the molecular mechanisms of restenosis and the genetic biomarkers predictive of restenosis. First, 350 patients are enrolled prospectively at the time of stent implantation. Blood is sampled prior to stent placement and afterwards at 2 weeks and 6 months. The clinical outcome of restenosis is determined 6 and 12 months after stent placement. The primary outcome is clinical restenosis at 6 months. The major secondary outcome is clinical restenosis at 12 months. Second, a corollary case-control analysis will be carried out with the enrollment of an additional 250 cases with a history of recurrent restenosis after treatment with BMS. Controls for this analysis are derived from the prospective cohort. PATIENTS AND METHODS Consecutive patients presenting to the cardiac catheterization laboratory are screened, informed about the study and enrolled after signing the consent form. Enrollment has been completed for the prospective cohort, and enrollment of the additional group is ongoing. A standardized questionnaire is used to collect clinical data primarily through direct patient interview to assess medical history, medication use, functional status, family history, environmental factors, and social history. Further data are abstracted from the medical charts and catheterization reports. A total of 276 clinical variables are collected per individual at baseline, and 49 variables are collected at each of the 6- and 12-month follow-up visits. A Clinical Events Committee adjudicates clinical outcomes. Blood samples are processed at each clinical enrollment site using standardized operating procedures. From each blood sample, several aliquots are prepared and stored of peripheral blood mononuclear cells, granulocytes, platelets, serum, and plasma. Additionally, a portion of each patients leukocytes is cryopreserved for future cell-line creation. Samples are frozen and shipped to the National Heart, Lung and Blood Institute (NHLBI). Additional materials generated in the analysis of the samples at the NHLBI are frozen and stored, including isolated genomic DNA, total RNA, reverse transcribed cDNA libraries and labeled RNA hybridization mixtures used in microarray analysis. Per individual in the prospective cohort, high-quality transcript profiles of peripheral blood mononuclear cells at each time of blood sampling are obtained using Affymetrix U133A microarrays (Affymetrix, Santa Clara, CA, USA). Per chip, this yields 495,930 features per individual per time of sampling. This represents expression levels for 22,283 genes per patients oer time of blood sampling, including 14,500 well-characterized human genes. Proteomics of plasma is performed with multidimensional liquid chromatography and tandem mass spectrometry. Protein expression is examined similarly to mRNA expression as a measure of gene expression. Genotyping is performed in two manners. First, those genes showing differential expression at the levels of mRNA and protein are investigated using a candidate gene approach. Specific variants in known gene regulatory regions, such as promoters, are sought initially, as those variants may explain differences in expression level. Second, a genome-wide scan is used to identify genetic loci that are associated with ISR. Those regions identified are further examined for genes that show differential expression in the mRNA microarray profiling or proteomics investigations. These genes are finely investigated for candidate SNPs and other gene variants. Complementary genomic and proteomic approaches are expected to be robust. Integration of data sets is accomplished using a variety of informatics tools, organization of gene expression into functional pathways, and investigation of physical maps of up- and downregulated sets of genes. CONCLUSIONS The CardioGene Study is designed to understand ISR. Global gene and protein expression profiling define molecular phenotypes of patients. Well-defined clinical phenotypes will be paired with genomic data to define analyses aimed to achieve several goals. These include determining blood gene and protein expression in patients with ISR, investigating the genetic basis of ISR, developing predictive gene and protein biomarkers, and the identification of new targets for treatment.

Predictors of Reperfusion Delay in Patients With Acute Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention from the HORIZONS-AMI Trial

Primary percutaneous coronary intervention (PCI) is the optimal method of reperfusion when performed expeditiously. Factors contributing to delays in PCI for ST-segment elevation myocardial infarction (STEMI) have not been thoroughly characterized or quantified. We sought to identify the factors associated with the delays to reperfusion in patients with STEMI undergoing primary PCI. Primary PCI was performed in 3,340 patients with STEMI in the international, multicenter Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction trial. Multivariate analysis was used to identify independent predictors of delay in achieving reperfusion from 38 baseline and procedural variables. A total of 905 patients (27.1%) presented to non-PCI hospitals and were subsequently transferred; the remainder presented to PCI hospitals. The most powerful independent predictor of the interval from symptom onset to arrival at the PCI hospital and the first door-to-balloon time was an initial presentation at a non-PCI hospital (median incremental 58- and 54-minute delay, respectively, both p < 0.001). Other independent predictors of prolonged door-to-balloon times included presentation with respiratory failure (42-minute incremental delay, p = 0.003), presentation during off-work hours (11-minute incremental delay, p < 0.001), and co-morbid conditions such as diabetes and heart failure. In conclusion, among patients undergoing primary PCI, presentation to a non-PCI hospital was the variable associated with the greatest delay to reperfusion. Systems of care that encourage ambulance diagnosis and direct delivery of patients with STEMI to a PCI hospital might shorten the overall door-to-balloon times and improve the clinical outcomes.