Morphology-Predicted Large-Scale Transition Number in Circulating Tumor Cells Identifies a Chromosomal Instability Biomarker Associated with Poor Outcome in Castration-Resistant Prostate Cancer.

Chromosomal instability (CIN) increases a tumor cell's ability to acquire chromosomal alterations, a mechanism by which tumor cells evolve, adapt, and resist therapeutics. We sought to develop a biomarker of CIN in circulating tumor cells (CTC) that are more likely to reflect the genetic diversity of patient's disease than a single-site biopsy and be assessed rapidly so as to inform treatment management decisions in real time. Large-scale transitions (LST) are genomic alterations defined as chromosomal breakages that generate chromosomal gains or losses of greater than or equal to10 Mb. Here we studied the relationship between the number of LST in an individual CTC determined by direct sequencing and morphologic features of the cells. This relationship was then used to develop a computer vision algorithm that utilizes CTC image features to predict the presence of a high (9 or more) versus low (8 or fewer) LST number in a single cell. As LSTs are a primary functional component of homologous recombination deficient cellular phenotypes, the image-based algorithm was studied prospectively on 10,240 CTCs in 367 blood samples obtained from 294 patients with progressing metastatic castration-resistant prostate cancer taken prior to starting a standard-of-care approved therapy. The resultant computer vision-based biomarker of CIN in CTCs in a pretreatment sample strongly associated with poor overall survival times in patients treated with androgen receptor signaling inhibitors and taxanes. SIGNIFICANCE: A rapidly assessable biomarker of chromosomal instability in CTC is associated with poor outcomes when detected in men with progressing mCRPC.

Genomic Analysis of Circulating Tumor Cells at the Single-Cell Level.

Circulating tumor cells (CTCs) have a great potential for noninvasive diagnosis and real-time monitoring of cancer. A comprehensive evaluation of four whole genome amplification (WGA)/next-generation sequencing workflows for genomic analysis of single CTCs, including PCR-based (GenomePlex and Ampli1), multiple displacement amplification (Repli-g), and hybrid PCR- and multiple displacement amplification-based [multiple annealing and loop-based amplification cycling (MALBAC)] is reported herein. To demonstrate clinical utilities, copy number variations (CNVs) in single CTCs isolated from four patients with squamous non-small-cell lung cancer were profiled. Results indicate that MALBAC and Repli-g WGA have significantly broader genomic coverage compared with GenomePlex and Ampli1. Furthermore, MALBAC coupled with low-pass whole genome sequencing has better coverage breadth, uniformity, and reproducibility and is superior to Repli-g for genome-wide CNV profiling and detecting focal oncogenic amplifications. For mutation analysis, none of the WGA methods were found to achieve sufficient sensitivity and specificity by whole exome sequencing. Finally, profiling of single CTCs from patients with non-small-cell lung cancer revealed potentially clinically relevant CNVs. In conclusion, MALBAC WGA coupled with low-pass whole genome sequencing is a robust workflow for genome-wide CNV profiling at single-cell level and has great potential to be applied in clinical investigations. Nevertheless, data suggest that none of the evaluated single-cell sequencing workflows can reach sufficient sensitivity or specificity for mutation detection required for clinical applications.

Identification and Characterization of Circulating Tumor Cells in Men Who have Undergone Prostatectomy for Clinically Localized, High Risk Prostate Cancer.

PURPOSE: Approximately 15% of men with newly diagnosed prostate cancer have high risk features which increase the risk of recurrence and metastasis. Better predictive biomarkers could allow for earlier detection of biochemical recurrence and change surveillance and adjuvant treatment paradigms. Circulating tumor cells are thought to represent the earliest form of metastases. However, their role as biomarkers in men with high risk, localized prostate cancer is not well defined. MATERIALS AND METHODS: Two to 5 months after prostatectomy we obtained blood samples from 37 patients with high risk, localized prostate cancer, defined as stage T3a or higher, Gleason score 8 or greater, or prostate specific antigen 20 ng/ml or greater. Circulating tumor cells were enumerated using a commercial platform. Matched tumor and single circulating tumor cell sequencing was performed. RESULTS: Circulating tumor cells were detected in 30 of 37 samples (81.1%) with a median of 2.4 circulating tumor cells per ml (range 0 to 22.9). Patients with detectable circulating tumor cells showed a trend toward shorter recurrence time (p=0.12). All patients with biochemical recurrence had detectable circulating tumor cells. Androgen receptor over expression was detected in 7 of 37 patients (18.9%). Patients with biochemical recurrence had more circulating tumor cell copy number aberrations (p=0.027). Matched tumor tissue and single circulating tumor cell sequencing revealed heterogeneity. CONCLUSIONS: We noted a high incidence of circulating tumor cell detection after radical prostatectomy and shorter time to biochemical recurrence in men with a higher circulating tumor cell burden and more circulating tumor cell copy number aberrations. Genomic alterations consistent with established copy number aberrations in prostate cancer were detectable in circulating tumor cells but often discordant with cells analyzed in bulk from primary lesions. With further testing in appropriately powered cohorts early circulating tumor cell detection could be an informative biomarker to assist with adjuvant treatment decisions.

Androgen receptor expression on circulating tumor cells in metastatic breast cancer.

PURPOSE: Androgen receptor (AR) is frequently detected in breast cancers, and AR-targeted therapies are showing activity in AR-positive (AR+) breast cancer. However, the role of AR in breast cancers is still not fully elucidated and the biology of AR in breast cancer remains incompletely understood. Circulating tumor cells (CTCs) can serve as prognostic and diagnostic tools, prompting us to measure AR protein expression and conduct genomic analyses on CTCs in patients with metastatic breast cancer. METHODS: Blood samples from patients with metastatic breast cancer were deposited on glass slides, subjected to nuclear staining with DAPI, and reacted with fluorescent-labeled antibodies to detect CD45, cytokeratin (CK), and biomarkers of interest (AR, estrogen receptor [ER], and HER2) on all nucleated cells. The stained slides were scanned and enumerated by non-enrichment-based non-biased approach independent of cell surface epithelial cell adhesion molecule (EpCAM) using the Epic Sciences CTC platform. Data were analyzed using established digital pathology algorithms. RESULTS: Of 68 patients, 51 (75%) had at least 1 CTC, and 49 of these 51 (96%) had hormone-receptor-positive (HR+)/HER2-negative primary tumors. AR was expressed in CK+ CTCs in 10 patients. Of these 10 patients, 3 also had ER expression in CK+ CTCs. Single cell genomic analysis of 78 CTCs from 1 of these 3 patients identified three distinct copy number patterns. AR+ cells had a lower frequency of chromosomal changes than ER+ and HER2+ cells. CONCLUSIONS: CTC enumeration and analysis using no enrichment or selection provides a non-biased approach to detect AR expression and chromosomal aberrations in CTCs in patients with metastatic breast cancer. The heterogeneity of intrapatient AR expression in CTCs leads to the new hypothesis that patients with AR+ CTCs have heterogeneous disease with multiple drivers. Further studies are warranted to investigate the clinical applicability of AR+ CTCs and their heterogeneity.

Phenotypic Heterogeneity of Circulating Tumor Cells Informs Clinical Decisions between AR Signaling Inhibitors and Taxanes in Metastatic Prostate Cancer.

The heterogeneity of an individual patient's tumor has been linked to treatment resistance, but quantitative biomarkers to rapidly and reproducibly evaluate heterogeneity in a clinical setting are currently lacking. Using established tools available in a College of American Pathologists-accredited and Clinical Laboratory Improvement Amendments-certified clinical laboratory, we quantified digital pathology features on 9,225 individual circulating tumor cells (CTC) from 179 unique metastatic castration-resistant prostate cancer (mCRPC) patients to define phenotypically distinct cell types. Heterogeneity was quantified on the basis of the diversity of cell types in individual patient samples using the Shannon index and associated with overall survival (OS) in the 145 specimens collected prior to initiation of the second or later lines of therapy. Low CTC phenotypic heterogeneity was associated with better OS in patients treated with androgen receptor signaling inhibitors (ARSI), whereas high heterogeneity was associated with better OS in patients treated with taxane chemotherapy. Overall, the results show that quantifying CTC phenotypic heterogeneity can help inform the choice between ARSI and taxanes in mCRPC patients. Cancer Res; 77(20); 5687-98. ©2017 AACR.

Effect of thyroid hormone on cardiac function following orthotopic heart transplantation in piglets.

Studies in adult HT have demonstrated improved cardiac function in the recipient following administration of T3 to the donor. The purpose of this experiment was to assess the effects of T3 on the function of the immature donor heart following HT in a piglet model. A total of 32 piglets were divided into 16 donors and 16 recipients. Following creation of brain death, half of the donor piglets were randomized to receive three doses of T3 (0.2 µg/kg) along with hydrocortisone (1 mg/kg). The donor hearts were then transplanted into the recipient piglets on CPB. Duration of survival off CPB, inotrope score, and EF of heart following CPB were evaluated. There were no differences between the two groups in age, weight, pre-brain death EF, T3 levels, and CPB times. Post-CPB survival times were inversely related to the ischemic times in both groups (Pearson r=-0.80, P<.001), and this relationship was not influenced by T3. There was no difference in inotrope score, EF, or biochemical assessment between the two groups. Administration of T3 in combination with hydrocortisone to the brain-dead donor confers no beneficial effect on myocardial function or survival following HT in a piglet model.

Cellular Expression of PD-L1 in the Peripheral Blood of Lung Cancer Patients is Associated with Worse Survival.

Background: Lung cancer treatment has become increasingly dependent upon invasive biopsies to profile tumors for personalized therapy. Recently, tumor expression of programmed death-ligand 1 (PD-L1) has gained interest as a potential predictor of response to immunotherapy. Circulating biomarkers present an opportunity for tumor profiling without the risks of invasive procedures. We characterized PD-L1 expression within populations of nucleated cells in the peripheral blood of lung cancer patients in hopes of expanding the role of liquid biopsy in this setting.Methods: Peripheral blood samples from a multi-institutional prospective study of patients with clinical diagnosis of lung cancer were subjected to cytomorphometric and immunohistochemical evaluation using single-cell, automated slide-based, digital pathology. PD-L1 expression was determined by immunofluorescence.Results: PD-L1 expression was detected within peripheral circulating cells associated with malignancy (CCAM) in 26 of 112 (23%) non-small cell lung cancer patients. Two distinct populations of nucleated, nonhematolymphoid, PD-L1-expressing cells were identified; cytokeratin positive (CK+, PD-L1+, CD45-) and cytokeratin negative (CK-, PD-L1+, CD45-) cells, both with cytomorphometric features (size, nuclear-to-cytoplasm ratio) consistent with tumor cells. Patients with >1.1 PD-L1(+) cell/mL (n = 14/112) experienced worse overall survival than patients with ≤1.1 PD-L1(+) cell/mL (2-year OS: 31.2% vs. 78.8%, P = 0.00159). In a Cox model adjusting for stage, high PD-L1(+) cell burden remained a significant predictor of mortality (HR = 3.85; 95% confidence interval, 1.64-9.09; P = 0.002).Conclusions: PD-L1 expression is detectable in two distinct cell populations in the peripheral blood of lung cancer patients and is associated with worse survival.Impact: These findings could represent a step forward in the development of minimally invasive liquid biopsies for the profiling of tumors. Cancer Epidemiol Biomarkers Prev; 26(7); 1139-45. ©2017 AACR.

Correlation of FCGRT genomic structure with serum immunoglobulin, albumin and farletuzumab pharmacokinetics in patients with first relapsed ovarian cancer.

Farletuzumab (FAR) is a humanized monoclonal antibody (mAb) that binds to folate receptor alpha. A Ph3 trial in ovarian cancer patients treated with carboplatin/taxane plus FAR or placebo did not meet the primary statistical endpoint. Subgroup analysis demonstrated that subjects with high FAR exposure levels (Cmin>57.6µg/mL) showed statistically significant improvements in PFS and OS. The neonatal Fc receptor (fcgrt) plays a central role in albumin/IgG stasis and mAb pharmacokinetics (PK). Here we evaluated fcgrt sequence and association of its promoter variable number tandem repeats (VNTR) and coding single nucleotide variants (SNV) with albumin/IgG levels and FAR PK in the Ph3 patients. A statistical correlation existed between high FAR Cmin and AUC in patients with the highest quartile of albumin and lowest quartile of IgG1. Analysis of fcgrt identified 5 different VNTRs in the promoter region and 9 SNVs within the coding region, 4 which are novel.

Phenotypic diversity of circulating tumour cells in patients with metastatic castration-resistant prostate cancer.

OBJECTIVES: To use a non-biased assay for circulating tumour cells (CTCs) in patients with prostate cancer (PCa) in order to identify non-traditional CTC phenotypes potentially excluded by conventional detection methods that are reliant on antigen- and/or size-based enrichment. PATIENTS AND METHODS: A total of 41 patients with metastatic castration-resistant PCa (mCRPC) and 20 healthy volunteers were analysed on the Epic CTC platform, via high-throughput imaging of DAPI expression and CD45/cytokeratin (CK) immunofluorescence (IF) on all circulating nucleated cells plated on glass slides. To confirm the PCa origin of CTCs, IF was used for androgen receptor (AR) expression and fluorescence in situ hybridization was used for PTEN and ERG assessment. RESULTS: Traditional CTCs (CD45- /CK+ /morphologically distinct) were identified in all patients with mCRPC and we also identified CTC clusters and non-traditional CTCs in patients with mCRPC, including CK- and apoptotic CTCs. Small CTCs (≤white blood cell size) were identified in 98% of patients with mCRPC. Total, traditional and non-traditional CTCs were significantly increased in patients who were deceased vs alive after 18 months; however, only non-traditional CTCs were associated with overall survival. Traditional and total CTC counts according to the Epic platform in the mCRPC cohort were also significantly correlated with CTC counts according to the CellSearch system. CONCLUSIONS: Heterogeneous non-traditional CTC populations are frequent in mCRPC and may provide additional prognostic or predictive information.

Chromosomal Instability Estimation Based on Next Generation Sequencing and Single Cell Genome Wide Copy Number Variation Analysis.

Genomic instability is a hallmark of cancer often associated with poor patient outcome and resistance to targeted therapy. Assessment of genomic instability in bulk tumor or biopsy can be complicated due to sample availability, surrounding tissue contamination, or tumor heterogeneity. The Epic Sciences circulating tumor cell (CTC) platform utilizes a non-enrichment based approach for the detection and characterization of rare tumor cells in clinical blood samples. Genomic profiling of individual CTCs could provide a portrait of cancer heterogeneity, identify clonal and sub-clonal drivers, and monitor disease progression. To that end, we developed a single cell Copy Number Variation (CNV) Assay to evaluate genomic instability and CNVs in patient CTCs. For proof of concept, prostate cancer cell lines, LNCaP, PC3 and VCaP, were spiked into healthy donor blood to create mock patient-like samples for downstream single cell genomic analysis. In addition, samples from seven metastatic castration resistant prostate cancer (mCRPC) patients were included to evaluate clinical feasibility. CTCs were enumerated and characterized using the Epic Sciences CTC Platform. Identified single CTCs were recovered, whole genome amplified, and sequenced using an Illumina NextSeq 500. CTCs were then analyzed for genome-wide copy number variations, followed by genomic instability analyses. Large-scale state transitions (LSTs) were measured as surrogates of genomic instability. Genomic instability scores were determined reproducibly for LNCaP, PC3, and VCaP, and were higher than white blood cell (WBC) controls from healthy donors. A wide range of LST scores were observed within and among the seven mCRPC patient samples. On the gene level, loss of the PTEN tumor suppressor was observed in PC3 and 5/7 (71%) patients. Amplification of the androgen receptor (AR) gene was observed in VCaP cells and 5/7 (71%) mCRPC patients. Using an in silico down-sampling approach, we determined that DNA copy number and genomic instability can be detected with as few as 350K sequencing reads. The data shown here demonstrate the feasibility of detecting genomic instabilities at the single cell level using the Epic Sciences CTC Platform. Understanding CTC heterogeneity has great potential for patient stratification prior to treatment with targeted therapies and for monitoring disease evolution during treatment.

The Initial Detection and Partial Characterization of Circulating Tumor Cells in Neuroendocrine Prostate Cancer.

PURPOSE: The transition of prostate adenocarcinoma to a predominantly androgen receptor (AR) signaling independent phenotype can occur in the later stages of the disease and is associated with low AR expression +/- the development of small-cell or neuroendocrine tumor characteristics. As metastatic tumor biopsies are not always feasible and are difficult to repeat, we sought to evaluate noninvasive methods to identify patients transitioning toward a neuroendocrine phenotype (NEPC). EXPERIMENTAL DESIGN: We prospectively studied a metastatic tumor biopsy, serum biomarkers, and circulating tumor cells (CTC, Epic Sciences) from patients with castration-resistant prostate cancer (CRPC) including those with pure or mixed NEPC histology present on biopsy. CTCs labeled with the patient's clinical status were used to learn features that discriminate NEPC patients, which was then applied to an independent cohort. RESULTS: Twenty-seven patients with CRPC including 12 NEPC and 5 with atypical clinical features suggestive of NEPC transition were studied. CTCs from NEPC patients demonstrated frequent clusters, low or absent AR expression, lower cytokeratin expression, and smaller morphology relative to typical CRPC. A multivariate analysis of protein and morphologic variables enabled distinguishing CTCs of NEPC from CRPC. This CTC classifier was applied to an independent prospective cohort of 159 metastatic CRPC patients and identified in 17/159 (10.7%) of cases, enriched in patients with high CTC burden (P < 0.01) and visceral metastases (P = 0.04). CONCLUSIONS: CTCs from patients with NEPC have unique morphologic characteristics, which were also identified in a subset of CRPC patients with aggressive clinical features potentially undergoing NEPC transition.

Analytical Validation and Capabilities of the Epic CTC Platform: Enrichment-Free Circulating Tumour Cell Detection and Characterization.

The Epic Platform was developed for the unbiased detection and molecular characterization of circulating tumour cells (CTCs). Here, we report assay performance data, including accuracy, linearity, specificity and intra/inter-assay precision of CTC enumeration in healthy donor (HD) blood samples spiked with varying concentrations of cancer cell line controls (CLCs). Additionally, we demonstrate clinical feasibility for CTC detection in a small cohort of metastatic castrate-resistant prostate cancer (mCRPC) patients. The Epic Platform demonstrated accuracy, linearity and sensitivity for the enumeration of all CLC concentrations tested. Furthermore, we established the precision between multiple operators and slide staining batches and assay specificity showing zero CTCs detected in 18 healthy donor samples. In a clinical feasibility study, at least one traditional CTC/mL (CK+, CD45-, and intact nuclei) was detected in 89 % of 44 mCRPC samples, whereas 100 % of samples had CTCs enumerated if additional CTC subpopulations (CK-/CD45- and CK+ apoptotic CTCs) were included in the analysis. In addition to presenting Epic Platform's performance with respect to CTC enumeration, we provide examples of its integrated downstream capabilities, including protein biomarker expression and downstream genomic analyses at single cell resolution.

Detection and Characterization of Circulating Tumour Cells from Frozen Peripheral Blood Mononuclear Cells.

Retrospective analysis of patient tumour samples is a cornerstone of clinical research. CTC biomarker characterization offers a non-invasive method to analyse patient samples. However, current CTC technologies require prospective blood collection, thereby reducing the ability to utilize archived clinical cohorts with long-term outcome data. We sought to investigate CTC recovery from frozen, archived patient PBMC pellets. Matched samples from both mCRPC patients and mock samples, which were prepared by spiking healthy donor blood with cultured prostate cancer cell line cells, were processed "fresh" via Epic CTC Platform or from "frozen" PBMC pellets. Samples were analysed for CTC enumeration and biomarker characterization via immunofluorescent (IF) biomarkers, fluorescence in-situ hybridization (FISH) and CTC morphology. In the frozen patient PMBC samples, the median CTC recovery was 18%, compared to the freshly processed blood. However, abundance and localization of cytokeratin (CK) and androgen receptor (AR) protein, as measured by IF, were largely concordant between the fresh and frozen CTCs. Furthermore, a FISH analysis of PTEN loss showed high concordance in fresh vs. frozen. The observed data indicate that CTC biomarker characterization from frozen archival samples is feasible and representative of prospectively collected samples.

Hybrid epicardial-endocardial ablation using a pericardioscopic technique for the treatment of atrial fibrillation.

BACKGROUND: Catheter ablation is an effective treatment for medically refractory, disabling atrial fibrillation (AF). Ablation success may be limited in patients with persistent or long-standing persistent AF. A pericardioscopic, hybrid epicardial-endocardial technique for AF ablation may be a preferred approach for such patients. Limited data are available using such an approach. OBJECTIVE: To evaluate 1-year outcomes of a hybrid technique for AF ablation. METHODS: A cohort of 101 patients underwent AF ablation using a transdiaphragmatic pericardioscopic, hybrid epicardial-endocardial technique. Patients were followed with 24-hour Holter monitors at 3-, 6-, and 12-month intervals. Symptom severity was assessed at baseline and follow-up by using the Canadian Cardiovascular Society Severity of Atrial Fibrillation scale. RESULTS: Mean AF duration was 5.9 years; 47% were persistent and 37% were long-standing persistent. Mean left atrial size was 5.1 cm (range 3.3-7 cm). Overall, 12-month arrhythmia-free survival was 66.3% after a single ablation procedure and 70.5% including repeat ablation. Repeat ablation was required in 6% of the patients and antiarrhythmic drug therapy in 37% of the patients. Quality of life improved significantly and was durable over 12-month follow-up. There were 2 deaths, which occurred in the early postoperative period: one due to atrioesophageal fistula and the second due to sudden cardiac death without apparent cause by autopsy. CONCLUSIONS: We report the largest series to date of a hybrid epicardial-endocardial, stand-alone ablation procedure using a pericardioscopic technique for the treatment of AF. While respecting the identified complications, our results demonstrate a high potential for successful treatment in a challenging patient population with AF.

Validating a nonhuman primate model of super-selective intraophthalmic artery chemotherapy: comparing ophthalmic artery diameters.

PURPOSE: Superselective intraophthalmic artery chemotherapy (SSIOAC) is being used for treatment of retinoblastoma; however, the hemodynamic consequences and toxicities are not fully known. We developed a nonhuman primate (NHP) model of SSIOAC and reported our clinical observations. For validation, we compared ophthalmic artery (OA) diameters between NHPs and children (<6 years). METHODS: Endovascular cannulation of the right OA was performed three times each in six adult male Rhesus macaques. Angiographic OA images were obtained and measured, and postmortem OAs were histologically sectioned and measured. Retrospectively, computed tomography (CT) and magnetic resonance (MR) angiography images of the head in children and adolescents (as an adult reference) were used to measure the OA luminal diameter at its origin. RESULTS: The median angiographic diameter of treated NHP OA origins (n = 6) was 1.06 mm (range 0.94-1.56). Histologic measurements (8 of 12 NHP OAs) gave a median diameter of 1.09 mm (range 0.95-1.41). In 98 children (from 169 consecutive CT and MR angiography studies; median age 1.01 years, range 0.01-5.74), 186 OAs were measurable at the origin (median luminal diameter 1.28 mm, range 0.82-2.00; P = 0.16 for the angiographic NHP diameters versus pediatric cohort). Angiographic measurements of 34 OAs (of 20 consecutive studies of adolescents; median age 16.55 years, range 14.40-18.18) gave a median luminal diameter of 1.45 mm (origin, range 1.13-1.66; P < 0.0001, adolescent versus pediatric). CONCLUSIONS: Measurements of the OA luminal diameter at its origin were similar between our NHP and pediatric cohort, validating our NHP model for testing both the hemodynamic consequences and toxicities of SSIOAC.

High resolution detection and analysis of CpG dinucleotides methylation using MBD-Seq technology.

Methyl-CpG binding domain protein sequencing (MBD-seq) is widely used to survey DNA methylation patterns. However, the optimal experimental parameters for MBD-seq remain unclear and the data analysis remains challenging. In this study, we generated high depth MBD-seq data in MCF-7 cell and developed a bi-asymmetric-Laplace model (BALM) to perform data analysis. We found that optimal efficiency of MBD-seq experiments was achieved by sequencing ∼100 million unique mapped tags from a combination of 500 mM and 1000 mM salt concentration elution in MCF-7 cells. Clonal bisulfite sequencing results showed that the methylation status of each CpG dinucleotides in the tested regions was accurately detected with high resolution using the proposed model. These results demonstrated the combination of MBD-seq and BALM could serve as a useful tool to investigate DNA methylome due to its low cost, high specificity, efficiency and resolution.

Simultaneous catheter and epicardial ablations enable a comprehensive atrial fibrillation procedure.

OBJECTIVE: Transmural and contiguous ablations and a comprehensive lesion pattern are difficult to create from the surface of a beating heart but are critical to the successful treatment of persistent, isolated atrial fibrillation. A codisciplinary simultaneous epicardial (surgical) and endocardial (catheter) procedure (Convergent procedure) addresses these issues. METHODS: Patients with symptomatic atrial fibrillation who failed medical treatment were evaluated. Using only pericardioscopy, the surgeon performed near-complete epicardial isolation of the pulmonary veins and a "box" lesion on the posterior left atrium using unipolar radiofrequency ablation. Simultaneous endocardial catheter radiofrequency ablation completed pulmonary vein isolation, performed a mitral annular and cavotricuspid isthmus line of block, and debulked the coronary sinus. Twelve-month results for the Convergent procedure were compared with 12-month results for concomitant and pericardioscopic (stand-alone transdiaphragmatic/thoracoscopic) atrial fibrillation procedures using unipolar radiofrequency ablation. RESULTS: Sixty-five patients underwent the Convergent procedure (mean age, 62 y; mean body surface area, 2.17 m²; mean atrial fibrillation duration, 4.8 y; mean left atrial size, 5.2 cm). Ninety-two percent were in persistent or long-standing persistent atrial fibrillation. At 12 months, evaluation with 24-hour Holter monitors found 82% of patients in sinus rhythm, while only 47% of pericardioscopic and 77% of concomitant patients treated with unipolar radiofrequency ablation were in sinus rhythm. CONCLUSIONS: Simultaneous epicardial and endocardial ablation improves outcomes for patients with persistent or longstanding persistent atrial fibrillation. This successful collaboration between cardiac surgeon and electrophysiologist is an important treatment option for patients with large left atriums and chronic atrial fibrillation.

The convergent procedure: a multidisciplinary atrial fibrillation treatment.

BACKGROUND: Persistent atrial fibrillation (AF) and long-standing persistent AF (LSPAF) are difficult to treat. Epicardial surgical and percutaneous catheter ablations have lower success rates in these patients. The convergent procedure, an endoscopic transdiaphragmatic ablation procedure with conventional percutaneous endocardial ablation, is examined. METHODS: Twenty-eight patients with persistent AF or LSPAF underwent the convergent procedure. All underwent combined surgical epicardial radiofrequency ablation and electrophysiological transseptal endocardial ablation to electrically isolate the 4 pulmonary veins, to exclude the posterior left atrium, to ablate the coronary sinus, and to confirm block at the cavotricuspid isthmus. Follow-up was with 24-hour Holter monitoring at 3 months, and 24-hour or 7-day monitoring at 6 and 12 months. RESULTS: The mean duration of the procedure was 187 minutes (102 surgical ablation minutes; 85 endocardial ablation minutes). The mean total fluoroscopy time was 35.1 minutes. Two patients developed symptomatic pericardial effusions requiring percutaneous drainage, and 1 patient has demonstrated phrenic nerve paresis. There were no deaths. At 3 months, 87% were in sinus rhythm, and 43% were free of AF and antiarrhythmic medications (AADs). At 6 months, 76% were free from AF and AADs. CONCLUSION: The convergent procedure effectively combines surgical and electrophysiological AF expertise to provide a viable treatment option to patients with persistent AF or LSPAF. Long-term follow-up is under way.

An alignment algorithm for bisulfite sequencing using the Applied Biosystems SOLiD System.

SUMMARY: Bisulfite sequencing allows cytosine methylation, an important epigenetic marker, to be detected via nucleotide substitutions. Since the Applied Biosystems SOLiD System uses a unique di-base encoding that increases confidence in the detection of nucleotide substitutions, it is a potentially advantageous platform for this application. However, the di-base encoding also makes reads with many nucleotide substitutions difficult to align to a reference sequence with existing tools, preventing the platform's potential utility for bisulfite sequencing from being realized. Here, we present SOCS-B, a reference-based, un-gapped alignment algorithm for the SOLiD System that is tolerant of both bisulfite-induced nucleotide substitutions and a parametric number of sequencing errors, facilitating bisulfite sequencing on this platform. An implementation of the algorithm has been integrated with the previously reported SOCS alignment tool, and was used to align CpG methylation-enriched Arabidopsis thaliana bisulfite sequence data, exhibiting a 2-fold increase in sensitivity compared to existing methods for aligning SOLiD bisulfite data. AVAILABILITY: Executables, source code, and sample data are available at http://solidsoftwaretools.com/gf/project/socs/