Augmented Symbolic Execution for Information Flow in Hardware Designs

We present SEIF, a methodology that combines static analysis with symbolic execution to verify and explicate information flow paths in a hardware design. SEIF begins with a statically built model of the information flow through a design and uses guided symbolic execution to recognize and eliminate non-flows with high precision or to find corresponding paths through the design state for true flows. We evaluate SEIF on two open-source CPUs, an AES core, and the AKER access control module. SEIF can exhaustively explore 10-12 clock cycles deep in 4-6 seconds on average, and can automatically account for 86-90% of the paths in the statically built model. Additionally, SEIF can be used to find multiple violating paths for security properties, providing a new angle for security verification

Unloading the Left Ventricle Before Reperfusion in Patients With Anterior ST-Segment-Elevation Myocardial Infarction

BACKGROUND: In ST-segment-elevation myocardial infarction (STEMI), infarct size correlates directly with heart failure and mortality. Preclinical testing has shown that, in comparison with reperfusion alone, mechanically unloading the left ventricle (LV) before reperfusion reduces infarct size and that 30 minutes of unloading activates a cardioprotective program that limits reperfusion injury. The DTU-STEMI pilot trial (Door-To-Unload in STEMI Pilot Trial) represents the first exploratory study testing whether LV unloading and delayed reperfusion in patients with STEMI without cardiogenic shock is safe and feasible. METHODS: In a multicenter, prospective, randomized exploratory safety and feasibility trial, we assigned 50 patients with anterior STEMI to LV unloading by using the Impella CP followed by immediate reperfusion (U-IR) versus delayed reperfusion after 30 minutes of unloading (U-DR). The primary safety outcome was a composite of major adverse cardiovascular and cerebrovascular events at 30 days. Efficacy parameters included the assessment of infarct size by using cardiac magnetic resonance imaging. RESULTS: All patients completed the U-IR (n=25) or U-DR (n=25) protocols with respective mean door-to-balloon times of 72 versus 97 minutes. Major adverse cardiovascular and cerebrovascular event rates were not statistically different between the U-IR versus U-DR groups (8% versus 12%, respectively, P=0.99). In comparison with the U-IR group, delaying reperfusion in the U-DR group did not affect 30-day mean infarct size measured as a percentage of LV mass (15±12% versus 13±11%, U-IR versus U-DR, P=0.53). CONCLUSIONS: We report that LV unloading using the Impella CP device with a 30-minute delay before reperfusion is feasible within a relatively short time period in anterior STEMI. The DTU-STEMI pilot trial did not identify prohibitive safety signals that would preclude proceeding to a larger pivotal study of LV unloading before reperfusion. An appropriately powered pivotal trial comparing LV unloading before reperfusion to the current standard of care is required. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT03000270