Clinical Validation of a Machine-Learned, Point-of-Care System to IDENTIFY Functionally Significant Coronary Artery Disease.

Many clinical studies have shown wide performance variation in tests to identify coronary artery disease (CAD). Coronary computed tomography angiography (CCTA) has been identified as an effective rule-out test but is not widely available in the USA, particularly so in rural areas. Patients in rural areas are underserved in the healthcare system as compared to urban areas, rendering it a priority population to target with highly accessible diagnostics. We previously developed a machine-learned algorithm to identify the presence of CAD (defined by functional significance) in patients with symptoms without the use of radiation or stress. The algorithm requires 215 s temporally synchronized photoplethysmographic and orthogonal voltage gradient signals acquired at rest. The purpose of the present work is to validate the performance of the algorithm in a frozen state (i.e., no retraining) in a large, blinded dataset from the IDENTIFY trial. IDENTIFY is a multicenter, selectively blinded, non-randomized, prospective, repository study to acquire signals with paired metadata from subjects with symptoms indicative of CAD within seven days prior to either left heart catheterization or CCTA. The algorithm's sensitivity and specificity were validated using a set of unseen patient signals (n = 1816). Pre-specified endpoints were chosen to demonstrate a rule-out performance comparable to CCTA. The ROC-AUC in the validation set was 0.80 (95% CI: 0.78-0.82). This performance was maintained in both male and female subgroups. At the pre-specified cut point, the sensitivity was 0.85 (95% CI: 0.82-0.88), and the specificity was 0.58 (95% CI: 0.54-0.62), passing the pre-specified endpoints. Assuming a 4% disease prevalence, the NPV was 0.99. Algorithm performance is comparable to tertiary center testing using CCTA. Selection of a suitable cut-point results in the same sensitivity and specificity performance in females as in males. Therefore, a medical device embedding this algorithm may address an unmet need for a non-invasive, front-line point-of-care test for CAD (without any radiation or stress), thus offering significant benefits to the patient, physician, and healthcare system.

Multicenter validation of a machine learning phase space electro-mechanical pulse wave analysis to predict elevated left ventricular end diastolic pressure at the point-of-care.

BACKGROUND: Phase space is a mechanical systems approach and large-scale data representation of an object in 3-dimensional space. Whether such techniques can be applied to predict left ventricular pressures non-invasively and at the point-of-care is unknown. OBJECTIVE: This study prospectively validated a phase space machine-learned approach based on a novel electro-mechanical pulse wave method of data collection through orthogonal voltage gradient (OVG) and photoplethysmography (PPG) for the prediction of elevated left ventricular end diastolic pressure (LVEDP). METHODS: Consecutive outpatients across 15 US-based healthcare centers with symptoms suggestive of coronary artery disease were enrolled at the time of elective cardiac catheterization and underwent OVG and PPG data acquisition immediately prior to angiography with signals paired with LVEDP (IDENTIFY; NCT #03864081). The primary objective was to validate a ML algorithm for prediction of elevated LVEDP using a definition of ≥25 mmHg (study cohort) and normal LVEDP ≤ 12 mmHg (control cohort), using AUC as the measure of diagnostic accuracy. Secondary objectives included performance of the ML predictor in a propensity matched cohort (age and gender) and performance for an elevated LVEDP across a spectrum of comparative LVEDP (<12 through 24 at 1 mmHg increments). Features were extracted from the OVG and PPG datasets and were analyzed using machine-learning approaches. RESULTS: The study cohort consisted of 684 subjects stratified into three LVEDP categories, ≤12 mmHg (N = 258), LVEDP 13-24 mmHg (N = 347), and LVEDP ≥25 mmHg (N = 79). Testing of the ML predictor demonstrated an AUC of 0.81 (95% CI 0.76-0.86) for the prediction of an elevated LVEDP with a sensitivity of 82% and specificity of 68%, respectively. Among a propensity matched cohort (N = 79) the ML predictor demonstrated a similar result AUC 0.79 (95% CI: 0.72-0.8). Using a constant definition of elevated LVEDP and varying the lower threshold across LVEDP the ML predictor demonstrated and AUC ranging from 0.79-0.82. CONCLUSION: The phase space ML analysis provides a robust prediction for an elevated LVEDP at the point-of-care. These data suggest a potential role for an OVG and PPG derived electro-mechanical pulse wave strategy to determine if LVEDP is elevated in patients with symptoms suggestive of cardiac disease.

Pericardial Decompression Syndrome After Drainage of Chronic Pericardial Effusions.

Pericardial decompression syndrome (PDS) is a potentially fatal disorder of left ventricular function that sometimes occurs after drainage of a pericardial effusion for cardiac tamponade. Patients at risk for PDS are difficult to identify. Here, we report 2 cases where PDS developed after drainage of effusions that had been present for years, suggesting that patients with chronic effusions are at higher risk for PDS. (Level of Difficulty: Advanced.).

Development and validation of a machine learned algorithm to IDENTIFY functionally significant coronary artery disease.

Introduction: Multiple trials have demonstrated broad performance ranges for tests attempting to detect coronary artery disease. The most common test, SPECT, requires capital-intensive equipment, the use of radionuclides, induction of stress, and time off work and/or travel. Presented here are the development and clinical validation of an office-based machine learned algorithm to identify functionally significant coronary artery disease without radiation, expensive equipment or induced patient stress. Materials and methods: The IDENTIFY trial (NCT03864081) is a prospective, multicenter, non-randomized, selectively blinded, repository study to collect acquired signals paired with subject meta-data, including outcomes, from subjects with symptoms of coronary artery disease. Time synchronized orthogonal voltage gradient and photoplethysmographic signals were collected for 230 seconds from recumbent subjects at rest within seven days of either left heart catheterization or coronary computed tomography angiography. Following machine learning on a proportion of these data (N = 2,522), a final algorithm was selected, along with a pre-specified cut point on the receiver operating characteristic curve for clinical validation. An unseen set of subject signals (N = 965) was used to validate the algorithm. Results: At the pre-specified cut point, the sensitivity for detecting functionally significant coronary artery disease was 0.73 (95% CI: 0.68-0.78), and the specificity was 0.68 (0.62-0.74). There exists a point on the receiver operating characteristic curve at which the negative predictive value is the same as coronary computed tomographic angiography, 0.99, assuming a disease incidence of 0.04, yielding sensitivity of 0.89 and specificity of 0.42. Selecting a point at which the positive predictive value is maximized, 0.12, yields sensitivity of 0.39 and specificity of 0.88. Conclusion: The performance of the machine learned algorithm presented here is comparable to common tertiary center testing for coronary artery disease. Employing multiple cut points on the receiver operating characteristic curve can yield the negative predictive value of coronary computed tomographic angiography and a positive predictive value approaching that of myocardial perfusion imaging. As such, a system employing this algorithm may address the need for a non-invasive, no radiation, no stress, front line test, and hence offer significant advantages to the patient, their physician, and healthcare system.

iPSCORE: A Resource of 222 iPSC Lines Enabling Functional Characterization of Genetic Variation across a Variety of Cell Types.

Large-scale collections of induced pluripotent stem cells (iPSCs) could serve as powerful model systems for examining how genetic variation affects biology and disease. Here we describe the iPSCORE resource: a collection of systematically derived and characterized iPSC lines from 222 ethnically diverse individuals that allows for both familial and association-based genetic studies. iPSCORE lines are pluripotent with high genomic integrity (no or low numbers of somatic copy-number variants) as determined using high-throughput RNA-sequencing and genotyping arrays, respectively. Using iPSCs from a family of individuals, we show that iPSC-derived cardiomyocytes demonstrate gene expression patterns that cluster by genetic background, and can be used to examine variants associated with physiological and disease phenotypes. The iPSCORE collection contains representative individuals for risk and non-risk alleles for 95% of SNPs associated with human phenotypes through genome-wide association studies. Our study demonstrates the utility of iPSCORE for examining how genetic variants influence molecular and physiological traits in iPSCs and derived cell lines.

Compatibility of Radiofrequency Surgical Sponge Detection Technology with Cardiac Implantable Electronic Devices and Temporary Pacemakers.

BACKGROUND: Radiofrequency (RF) technology has improved detection of retained surgical sponges with a reported 100% sensitivity and specificity. However, the potential for interactions of the RF signals emitted by the detection system with cardiac implantable electronic devices (CIEDs) or temporary pacemakers may limit its use in those patients with these devices. This study investigated whether RF detection technology causes interference or clinically significant changes in the programmed settings of implanted pacemakers and defibrillators or temporary epicardial pacemakers. METHODS: Fifty patients who were scheduled either for CIED removal or placement of a temporary epicardial pacemaker (at the time of open heart surgery) were recruited for this study. Device settings and measurements from separate interrogations before and after scanning with the RF detection system were compared. For the temporary pacemakers, we observed for any changes in hemodynamics or signs of pacing interference. RESULTS: Twenty (40%) pacemakers, 20 (40%) implantable cardioverter defibrillators, and 10 (20%) temporary pacemakers were analyzed in this study. During scanning, no signal interference was detected in any permanent device, and there were no significant changes in programmed settings after scanning with the RF detection system. However, pacing inhibition was detected with temporary pacing systems when programmed to a synchronous mode (DDD). CONCLUSIONS: RF detection technology can be safely used to scan for retained surgical sponges in patients with permanent CIEDs and temporary pacemakers set to asynchronous mode.

An inactive geminin mutant that binds cdt1.

The initiation of DNA replication is tightly regulated in order to ensure that the genome duplicates only once per cell cycle. In vertebrate cells, the unstable regulatory protein Geminin prevents a second round of DNA replication by inhibiting the essential replication factor Cdt1. Cdt1 recruits mini-chromosome maintenance complex (MCM2-7), the replication helicase, into the pre-replication complex (pre-RC) at origins of DNA replication. The mechanism by which Geminin inhibits MCM2-7 loading by Cdt1 is incompletely understood. The conventional model is that Geminin sterically hinders a direct physical interaction between Cdt1 and MCM2-7. Here, we describe an inactive missense mutant of Geminin, GemininAWA, which binds to Cdt1 with normal affinity yet is completely inactive as a replication inhibitor even when added in vast excess. In fact, GemininAWA can compete with GemininWT for binding to Cdt1 and prevent it from inhibiting DNA replication. GemininAWA does not inhibit the loading of MCM2-7 onto DNA in vivo, and in the presence of GemininAWA, nuclear DNA is massively over-replicated within a single S phase. We conclude that Geminin does not inhibit MCM loading by simple steric interference with a Cdt1-MCM2-7 interaction but instead works by a non-steric mechanism, possibly by inhibiting the histone acetyltransferase HBO1.

Pocket infections of cardiac implantable electronic devices treated by negative pressure wound therapy.

AIMS: Managing an infection of the pocket of a cardiac implantable electronic device (CIED) is frequently challenging. The wound is often treated with a drain or wet-to-dry dressings that allow healing by secondary intention. Such treatment can prolong the hospital stay and can frequently result in a disfiguring scar. Negative pressure wound therapy (NPWT) has been frequently used to promote the healing of chronic or infected surgical wounds. Here we describe the first series of 28 patients in which NPWT was successfully used to treat CIED pocket infections. METHODS AND RESULTS: After removal of the CIED and debridement of the pocket, a negative pressure of 125 mmHg continuously applied to the wound through an occlusive dressing. Negative pressure wound therapy was continued for a median of 5 days (range 2-15 days) and drained an average of 260 mL sero-sanguineous fluid (range 35-970 mL). At the conclusion of NPWT, delayed primary closure of the pocket was performed with 1-0 prolene mattress sutures. The median length of stay after CIED extraction was 11.0 days (range 2-43 days). Virtually all infected pockets healed without complications and without evidence of recurrent infection over a median follow-up of 49 days (range 10-752 days). One patient developed a recurrent infection when NPWT was discontinued prematurely and a new device was implanted at the infected site. CONCLUSION: We conclude that NPWT is a safe and effective means to promote healing of infected pockets with a low incidence of recurrent infection and a satisfactory cosmetic result.

Final 5-year results of the TAXUS ATLAS, TAXUS ATLAS Small Vessel, and TAXUS ATLAS Long Lesion clinical trials of the TAXUS Liberté paclitaxel-eluting stent in de-novo coronary artery lesions.

OBJECTIVE: To report the final, cumulative, 5-year outcomes from the TAXUS ATLAS program, which studied the use of the TAXUS Liberté paclitaxel-eluting stent in de-novo coronary artery lesions. METHODS: TAXUS ATLAS Workhorse, Small Vessel, and Long Lesion are nonrandomized studies comparing TAXUS Liberté (N=871), TAXUS Liberté 2.25 mm (N=261), and TAXUS Liberté 38 mm (N=150) stents, respectively, with case-matched TAXUS Express historical controls. RESULTS: In the unadjusted analysis, TAXUS Liberté showed comparable 5-year rates of major adverse cardiac events (27.1% TAXUS Express vs. 26.2% TAXUS Liberté, P=0.70) in workhorse lesions and greater 5-year cumulative freedom from target lesion revascularization (78.4 vs. 87.3%, P=0.03) in small vessels. In addition, a lower periprocedural myocardial infarction rate (MI, 4.1 vs. 0.0%; P=0.01) was observed in long lesions versus TAXUS Express. After propensity score adjustment, no statistically significant effect of TAXUS Liberté on the 5-year rates of TLR in small vessels (17.9 vs. 13.3%, P=0.36) or MI in long lesions (9.1 vs. 7.0%, P=0.53) was found, although the rates remained numerically lower with TAXUS Liberté. CONCLUSION: Cumulative 5-year results of the TAXUS ATLAS studies suggest that the TAXUS Liberté stent provides similar safety and effectiveness in workhorse lesions, and may provide lower revascularization rates in small vessels and lower periprocedural MI rates in long lesions compared with the TAXUS Express stent, although no statistically significant differences were found following propensity adjustment.

Geminin is required for mitotic proliferation of spermatogonia.

Spermatogonial stem cells divide throughout life, maintaining their own population and giving rise to differentiated gametes. The unstable regulatory protein Geminin is thought to be one of the factors that determine whether stem cells continue to divide or terminally differentiate. Geminin regulates the extent of DNA replication and is thought to maintain cells in an undifferentiated state by inhibiting various transcription factors and chromatin remodeling proteins. To examine how Geminin might regulate spermatogenesis, we developed two conditional mouse models in which the Geminin gene (Gmnn) is deleted from either spermatogonia or meiotic spermatocytes. Deleting Geminin from spermatogonia causes complete sterility in male mice. Gmnn(-/-) spermatogonia disappear during the initial wave of mitotic proliferation that occurs during the first week of life. Gmnn(-/-) spermatogonia exhibit more double-stranded DNA breaks than control cells, consistent with a defect in DNA replication. They maintain expression of genes associated with the undifferentiated state and do not prematurely express genes characteristic of more differentiated spermatogonia. In contrast, deleting Geminin from spermatocytes does not disrupt meiosis or the differentiation of spermatids into mature sperm. In females, Geminin is not required for meiosis, oocyte differentiation, or fertility after the embryonic period of mitotic proliferation has ceased. We conclude that Geminin is absolutely required for mitotic proliferation of spermatogonia but does not regulate their differentiation. Our results suggest that Geminin maintains replication fidelity during the mitotic phase of spermatogenesis, ensuring the precise duplication of genetic information for transmission to the next generation.

Percutaneous coronary intervention with second-generation paclitaxel-eluting stents versus everolimus-eluting stents in United States contemporary practice (REWARDS TLX Trial).

Registry Experience at the Washington Hospital Center, DES - Taxus Liberte Versus Xience V (REWARDS TLX) is a physician-initiated, retrospective, real-world, multicenter, observational study for all patients >18 years of age subjected to percutaneous coronary intervention with everolimus-eluting stents (EESs) or paclitaxel-eluting stents (PESs). Outcomes of patients receiving a TAXUS Liberté or XIENCE V drug-eluting stent were compared. Baseline clinical, procedural, and follow-up data at 12 months were collected from 10 clinical centers by an electronic data capture system. The study's primary end point was major adverse cardiac events: a composite of all-cause death, Q-wave myocardial infarction, target vessel revascularization, and stent thrombosis. The trial is registered with http://www.clinicaltrials.gov (NCT01134159). Data were entered for 1,195 patients (PES, n = 595; EES, n = 600). Baseline clinical characteristics were similar except for higher dyslipidemia, systemic hypertension, and family history of coronary artery disease in the EES group. In-hospital outcome was similar between groups, with an overall in-hospital stent thrombosis rate of 0.2%. The primary end point at 12 months was similar (EES 7.8% vs 10.8%, p = 0.082). Overall stent thrombosis rate was lower in the EES group (0.3% vs 1.2%, respectively, p = 0.107); however, target lesion revascularization was similar (PES, hazard ratio 1.46, 95% confidence interval 0.98 to 2.19, p = 0.064). There was no difference in overall mortality between groups. In conclusion, second-generation EESs and PESs demonstrated similar efficacy and safety profiles for broadened patient and lesion subsets compared to a selected population from the pivotal trials. However, for composite efficacy and safety end points, EESs outperformed second-generation PESs.

Geminin is required for zygotic gene expression at the Xenopus mid-blastula transition.

In many organisms early development is under control of the maternal genome and zygotic gene expression is delayed until the mid-blastula transition (MBT). As zygotic transcription initiates, cell cycle checkpoints become activated and the tempo of cell division slows. The mechanisms that activate zygotic transcription at the MBT are incompletely understood, but they are of interest because they may resemble mechanisms that cause stem cells to stop dividing and terminally differentiate. The unstable regulatory protein Geminin is thought to coordinate cell division with cell differentiation. Geminin is a bi-functional protein. It prevents a second round of DNA replication during S and G2 phase by binding and inhibiting the essential replication factor Cdt1. Geminin also binds and inhibits a number of transcription factors and chromatin remodeling proteins and is thought to keep dividing cells in an undifferentiated state. We previously found that the cells of Geminin-deficient Xenopus embryos arrest in G2 phase just after the MBT then disintegrate at the onset of gastrulation. Here we report that they also fail to express most zygotic genes. The gene expression defect is cell-autonomous and is reproduced by over-expressing Cdt1 or by incubating the embryos in hydroxyurea. Geminin deficient and hydroxyurea-treated blastomeres accumulate DNA damage in the form of double stranded breaks. Bypassing the Chk1 pathway overcomes the cell cycle arrest caused by Geminin depletion but does not restore zygotic gene expression. In fact, bypassing the Chk1 pathway by itself induces double stranded breaks and abolishes zygotic transcription. We did not find evidence that Geminin has a replication-independent effect on transcription. We conclude that Geminin is required to maintain genome integrity during the rapid cleavage divisions, and that DNA damage disrupts zygotic gene transcription at the MBT, probably through activation of DNA damage checkpoint pathways.

Economic outcomes of percutaneous coronary intervention with drug-eluting stents versus bypass surgery for patients with left main or three-vessel coronary artery disease: one-year results from the SYNTAX trial.

OBJECTIVES: To evaluate the cost-effectiveness of alternative approaches to revascularization for patients with three-vessel or left main coronary artery disease (CAD). BACKGROUND: Previous studies have demonstrated that, despite higher initial costs, long-term costs with bypass surgery (CABG) in multivessel CAD are similar to those for percutaneous coronary intervention (PCI). The impact of drug-eluting stents (DES) on these results is unknown. METHODS: The SYNTAX trial randomized 1,800 patients with left main or three-vessel CAD to either CABG (n = 897) or PCI using paclitaxel-eluting stents (n = 903). Resource utilization data were collected prospectively for all patients, and cumulative 1-year costs were assessed from the perspective of the U.S. healthcare system. RESULTS: Total costs for the initial hospitalization were $5,693/patient higher with CABG, whereas follow-up costs were $2,282/patient higher with PCI due mainly to more frequent revascularization procedures and higher outpatient medication costs. Total 1-year costs were thus $3,590/patient higher with CABG, while quality-adjusted life expectancy was slightly higher with PCI. Although PCI was an economically dominant strategy for the overall population, cost-effectiveness varied considerably according to angiographic complexity. For patients with high angiographic complexity (SYNTAX score > 32), total 1-year costs were similar for CABG and PCI, and the incremental cost-effectiveness ratio for CABG was $43,486 per quality-adjusted life-year gained. CONCLUSIONS: Among patients with three-vessel or left main CAD, PCI is an economically attractive strategy over the first year for patients with low and moderate angiographic complexity, while CABG is favored among patients with high angiographic complexity.

Propensity-matched patient-level comparison of the TAXUS Liberté and TAXUS element (ION) paclitaxel-eluting stents.

Stent design, metal alloy composition, and strut thickness may influence late lumen loss and clinical outcomes after bare metal stent deployment; however, their impact on outcomes after drug-eluting stent deployment is unknown. Although the TAXUS Liberté and ION paclitaxel-eluting stents use similar polymer and drug, the ION stent incorporates a novel thin-strut platinum chromium metal alloy and cell design. We therefore compared patient-level data from 2,298 subjects enrolled into the TAXUS ATLAS (TAXUS Liberté) and PERSEUS (ION) clinical trials. Propensity-score (1:1) matching was performed to adjust for covariate imbalance between stent types. Twelve-month major adverse cardiac events were less frequent after use of the ION compared to the TAXUS Liberté (12.7% vs 8.3%, p <0.001, unadjusted; 12.0% vs 7.5%, p = 0.007, propensity matched) largely because of decreased non-Q-wave myocardial infarction (MI; 2.9% vs 1.4%, p = 0.01, unadjusted; 3.2% vs 0.9%, p = 0.004, propensity matched). The MI difference was predominantly periprocedural and in patients treated with a single stent. In conclusion, this exploratory post hoc analysis demonstrated that the ION was associated with fewer adverse clinical events than the TAXUS Liberté because of decreased non-Q-wave MI. Stent platform-related variables may influence clinical outcomes after drug-eluting stent use despite similar polymer and drug elution. Differences in adjunctive pharmacotherapy and/or stenting technique may also be contributory.