Applying model-based systems engineering to architecture optimization and selection during system acquisition

2018 Fall.Includes bibliographical references.The architecture selection process early in a major system acquisition is a critical step in determining the overall affordability and technical performance success of a program. There are recognized deficiencies that frequently occur in this step such as poor transparency into the final selection decision and excessive focus on lowest cost, which is not necessarily the best value for all of the stakeholders. This research investigates improvements to the architecture selection process by integrating Model-Based Systems Engineering (MBSE) techniques, enforcing rigorous, quantitative evaluation metrics with a corresponding understanding of uncertainties, and stakeholder feedback in order to generate an architecture that is more optimized and trusted to provide better value for the stakeholders. Three case studies were analyzed to demonstrate this proposed process. The first focused on a satellite communications System of Systems (SoS) acquisition to demonstrate the overall feasibility and applicability of the process. The second investigated an electro-optical remote sensing satellite system to compare this proposed process to a current architecture selection process typified by the United States Department of Defense (U.S. DoD) Analysis of Alternatives (AoA). The third case study analyzed the evaluation of a service-oriented architecture (SOA) providing satellite command and control with cyber security protections in order to demonstrate rigorous accounting of uncertainty through the architecture evaluation and selection. These case studies serve to define and demonstrate a new, more transparent and trusted architecture selection process that consistently provides better value for the stakeholders of a major system acquisition. While the examples in this research focused on U.S. DoD and other major acquisitions, the methodology developed is broadly applicable to other domains where this is a need for optimization of enterprise architectures as the basis for effective system acquisition. The results from the three case studies showed the new process outperformed the current methodology for conducting architecture evaluations in nearly all criteria considered and in particular selects architectures of better value, provides greater visibility into the actual decision making, and improves trust in the decision through a robust understanding of uncertainty. The primary contribution of this research then is improved information support to an architecture selection in the early phases of a system acquisition program. The proposed methodology presents a decision authority with an integrated assessment of each alternative, traceable to the concerns of the system's stakeholders, and thus enables a more informed and objective selection of the preferred alternative. It is recommended that the methodology proposed in this work is considered for future architecture evaluations

Early Utilization of Mechanical Circulatory Support in Acute Myocardial Infarction Complicated by Cardiogenic Shock: The National Cardiogenic Shock Initiative

Background Acute myocardial infarction complicated by cardiogenic shock (AMI‐CS) is associated with significant morbidity and mortality. Mechanical circulatory support (MCS) devices increase systemic blood pressure and end organ perfusion while reducing cardiac filling pressures. Methods and Results The National Cardiogenic Shock Initiative (NCT03677180) is a single‐arm, multicenter study. The purpose of this study was to assess the feasibility and effectiveness of utilizing early MCS with Impella in patients presenting with AMI‐CS. The primary end point was in‐hospital mortality. A total of 406 patients were enrolled at 80 sites between 2016 and 2020. Average age was 64±12 years, 24% were female, 17% had a witnessed out‐of‐hospital cardiac arrest, 27% had in‐hospital cardiac arrest, and 9% were under active cardiopulmonary resuscitation during MCS implantation. Patients presented with a mean systolic blood pressure of 77.2±19.2 mm Hg, 85% of patients were on vasopressors or inotropes, mean lactate was 4.8±3.9 mmol/L and cardiac power output was 0.67±0.29 watts. At 24 hours, mean systolic blood pressure improved to 103.9±17.8 mm Hg, lactate to 2.7±2.8 mmol/L, and cardiac power output to 1.0±1.3 watts. Procedural survival, survival to discharge, survival to 30 days, and survival to 1 year were 99%, 71%, 68%, and 53%, respectively. Conclusions Early use of MCS in AMI‐CS is feasible across varying health care settings and resulted in improvements to early hemodynamics and perfusion. Survival rates to hospital discharge were high. Given the encouraging results from our analysis, randomized clinical trials are warranted to assess the role of utilizing early MCS, using a standardized, multidisciplinary approach

Impact of early mechanical support in patients with acute myocardial infarction complicated by cardiogenic shock with culprit left main coronary artery disease: Insights from national cardiogenic shock initiative

Background: Previous retrospective studies have demonstrated unacceptably high hospital mortality (60-65%) in patients presenting with acute myocardial infarction complicated by cardiogenic shock (AMICS) undergoing primary percutaneous coronary intervention (PCI) of a culprit left main coronary artery (LMCA). We sought to assess the impact of early mechanical support (MCS) specifically in this cohort using data from the National Cardiogenic Shock Initiative, a single-arm, prospective, multicenter study. Methods: Between July 2016 and August 2018, 23 sites participated in the study. All centers agreed to treat patients with AMICS using a standard protocol emphasizing invasive hemodynamic monitoring and rapid initiation of MCS. Inclusion and exclusion criteria mimicked those of the \u27SHOCK\u27 trial with an additional exclusion criterion being use of intra-aortic balloon pump counter-pulsation prior to MCS. Results: Out of a total of 104 patients enrolled, 16 patients had a culprit LMCA. In the culprit LMCA cohort, the mean age was 64 ± 11 years and 75% were males. Prior to MCS, 25% had witnessed out of hospital cardiac arrest, 25% had in-hospital cardiac arrest and 32% were under active cardiopulmonary resuscitation during MCS implantation. In accordance with the protocol, 87% of patients had an MCS device inserted prior to PCI. Right heart catheterization and hemodynamic monitoring was performed in 84% of patients. Cardiac power output improved from 0.68 W pre-procedure to 0.98 W 24-hours post-procedure (p = 0.04). TIMI III flow was achieved in 88% of patients post-reperfusion. Mean length of stay was 16 days. Left ventricle ejection fraction improved from 12.5 ± 3.8 % baseline to 25.6 ± 9.6 % at the time of discharge (p = 0.002). Survival to explant was 94% and survival to discharge was 75%. Conclusions: Early MCS in patients with AMICS with a culprit LMCA was associated with rapid improvement in hemodynamics and improved survival to discharge

Improved Outcomes Associated with the use of Shock Protocols: Updates from the National Cardiogenic Shock Initiative

BACKGROUND: The National Cardiogenic Shock Initiative is a single-arm, prospective, multicenter study to assess outcomes associated with early mechanical circulatory support (MCS) in patients presenting with acute myocardial infarction and cardiogenic shock (AMICS) treated with percutaneous coronary intervention (PCI). METHODS: Between July 2016 and February 2019, 35 sites participated and enrolled into the study. All centers agreed to treat patients with AMICS using a standard protocol emphasizing invasive hemodynamic monitoring and rapid initiation of MCS. Inclusion and exclusion criteria mimicked those of the SHOCK trial with an additional exclusion criteria of intra-aortic balloon pump counter-pulsation prior to MCS. RESULTS: A total of 171 consecutive patients were enrolled. Patients had an average age of 63 years, 77% were male, and 68% were admitted with AMICS. About 83% of patients were on vasopressors or inotropes, 20% had a witnessed out of hospital cardiac arrest, 29% had in-hospital cardiac arrest, and 10% were under active cardiopulmonary resuscitation during MCS implantation. In accordance with the protocol, 74% of patients had MCS implanted prior to PCI. Right heart catheterization was performed in 92%. About 78% of patients presented with ST-elevation myocardial infarction with average door to support times of 85 ± 63 min and door to balloon times of 87 ± 58 min. Survival to discharge was 72%. Creatinine ≥2, lactate \u3e4, cardiac power output (CPO) CONCLUSION: In contemporary practice, use of a shock protocol emphasizing best practices is associated with improved outcomes

Improved Outcomes Associated with the use of Shock Protocols: Updates from the National Cardiogenic Shock Initiative.

BACKGROUND: The National Cardiogenic Shock Initiative is a single-arm, prospective, multicenter study to assess outcomes associated with early mechanical circulatory support (MCS) in patients presenting with acute myocardial infarction and cardiogenic shock (AMICS) treated with percutaneous coronary intervention (PCI). METHODS: Between July 2016 and February 2019, 35 sites participated and enrolled into the study. All centers agreed to treat patients with AMICS using a standard protocol emphasizing invasive hemodynamic monitoring and rapid initiation of MCS. Inclusion and exclusion criteria mimicked those of the SHOCK trial with an additional exclusion criteria of intra-aortic balloon pump counter-pulsation prior to MCS. RESULTS: A total of 171 consecutive patients were enrolled. Patients had an average age of 63 years, 77% were male, and 68% were admitted with AMICS. About 83% of patients were on vasopressors or inotropes, 20% had a witnessed out of hospital cardiac arrest, 29% had in-hospital cardiac arrest, and 10% were under active cardiopulmonary resuscitation during MCS implantation. In accordance with the protocol, 74% of patients had MCS implanted prior to PCI. Right heart catheterization was performed in 92%. About 78% of patients presented with ST-elevation myocardial infarction with average door to support times of 85 ± 63 min and door to balloon times of 87 ± 58 min. Survival to discharge was 72%. Creatinine ≥2, lactate \u3e4, cardiac power output (CPO) CONCLUSION: In contemporary practice, use of a shock protocol emphasizing best practices is associated with improved outcomes

Culprit-Vessel Versus Multivessel Percutaneous Coronary Intervention in Cardiogenic Shock: Insights From the National Cardiogenic Shock Initiative

Background: The National Cardiogenic Shock Initiative (NCSI) is a single-arm, prospective, multicenter study to assess clinical outcomes associated with early mechanical circulatory support (MCS) in patients presenting with acute myocardial infarction and cardiogenic shock (AMICS) treated with percutaneous coronary intervention (PCI). We aim to determine if patients with AMICS with MCS benefit from culprit versus multivessel PCI. Methods: From July 2016 to February 2019, patients who presented with AMICS to the 35 participating hospitals were included in the study and were treated using a standard protocol with invasive hemodynamic monitoring, early MCS, and PCI. Patients with multivessel coronary artery disease (MVCAD) were analyzed on the basis of culprit-only PCI (CV-PCI) versus multivessel PCI (MV-PCI). Results: Among 171 patients included in the NCSI, 108 had MVCAD, of whom 69 underwent MV-PCI (64%) and 39 CV-PCI (36%). The mean ages were 64.8 years for the MV-PCI group and 63.2 years for the CV-PCI group; in both groups, the majority were men (81.2% and 79.5%). Patients who underwent MV-PCI had higher frequencies of diabetes (44.6% vs. 40.5%), heart failure (34.4% vs. 22.2%), prior myocardial infarction (24.2% vs. 15.8%), and prior stroke (14.1% vs. 5.4%) and a lower frequency of chronic kidney disease (12.3% vs. 18.4%) compared with those who underwent CV-PCI. In-hospital mortality was not significantly different between groups (29% for MV-PCI vs. 25.6% for CV-PCI; p = 0.824), as well as the rate of acute kidney injury (AKI) (65.1% vs. 61.1%; p = 0.828). Conclusion: Among patients with AMICS supported with MCS, the in-hospital mortality and incidence of AKI were not significantly different if they underwent multivessel or culprit vessel PCI. Further randomized controlled trials are needed to evaluate multivessel versus culprit vessel PCI in cardiogenic shock with the use of MCS