Thread-level speculation is a technique that enables parallel execution of sequential applications on a multiprocessor. This paper describes the complete implementation of the support for threadlevel speculation on the Hydra chip multiprocessor (CMP). The support consists of a number of software speculation control handlers and modifications to the shared secondary cache memory system of the CMP. This support is evaluated using five representative integer applications. Our results show that the speculative support is only able to improve performance when there is a substantial amount of medium-grained loop-level parallelism in the application. When the granularity of parallelism is too small or there is little inherent parallelism in the application, the overhead of the software handlers overwhelms any potential performance benefits from speculative-thread parallelism. Overall, thread-level speculation still appears to be a promising approach for expanding the class of applications that can be automatically parallelized, but more hardware intensive implementations for managing speculation control are required to achieve performance improvements on a wide class of integer applications.

Elective cardiac catheterization can be safely performed in patients with ESLD with outcomes (vascular and bleeding complications, length of hospital stay and in-hospital mortality) similar to patients without liver disease despite significant thrombocytopenia and elevated INR in patients with ESLD. Practices such as platelet transfusion for platelets <60,000 μL, prophylactic FFP transfusion for INR ≥ 1.6, less frequent use of antiplatelet therapy and more frequent use of smaller vascular sheaths may have contributed to the safety of cardiac catheterization in ESLD patients.

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Background: Over the last decade, there has been a significant increase in the use of percutaneous left ventricular assist devices(p-LVADs). p-LVADs are being increasingly used during complex coronary interventions and for acute cardiogenic shock.These large bore percutaneous devices have a higher risk of vascular complications.We examined the vascular complication rates from the use of p-LVAD in a national database.Methods: We conducted a secondary analysis of the National In-patient Sample (NIS) dataset from 2005 till 2015. We used the ICD-9-CM procedure codes 37.68 and 37.62 for p-LVAD placement regardless of indications. We investigated common vascular complications, defining them by the validated ICD 9 CM codes. χ 2 test and t test were used for categorical and continuous variables, respectively for comparison.Results: A total of 31,263 p-LVAD placements were identified during the period studied. A majority of patients were male (72.68%) and 64.44% were white. The overall incidence of vascular complications was 13.53%, out of which 56% required surgical treatment. Acute limb thromboembolism and bleeding requiring transfusion accounted for 27.6% and 21.8% of all vascular complications. Occurrence of a vascular complication was associated with significantly higher in-hospital mortality (37.77% vs. 29.95%, p < .001), length of stay (22.7 vs. 12.2 days, p < .001) and cost of hospitalization ($ 161,923 vs. $ 95,547, p < .001).Conclusions: There is a high incidence of vascular complications with p-LVAD placement including need for vascular surgery. These complications are associated with a higher in-hospital, LOS and hospitalization costs. These findings should be factored into the decision-making for p-LVAD placement.

ImportanceIn patients with severe aortic valve stenosis at intermediate surgical risk, transcatheter aortic valve replacement (TAVR) with a self-expanding supra-annular valve was noninferior to surgery for all-cause mortality or disabling stroke at 2 years. Comparisons of longer-term clinical and hemodynamic outcomes in these patients are limited.ObjectiveTo report prespecified secondary 5-year outcomes from the Symptomatic Aortic Stenosis in Intermediate Risk Subjects Who Need Aortic Valve Replacement (SURTAVI) randomized clinical trial.Design, Setting, and ParticipantsSURTAVI is a prospective randomized, unblinded clinical trial. Randomization was stratified by investigational site and need for revascularization determined by the local heart teams. Patients with severe aortic valve stenosis deemed to be at intermediate risk of 30-day surgical mortality were enrolled at 87 centers from June 19, 2012, to June 30, 2016, in Europe and North America. Analysis took place between August and October 2021.InterventionPatients were randomized to TAVR with a self-expanding, supra-annular transcatheter or a surgical bioprosthesis.Main Outcomes and MeasuresThe prespecified secondary end points of death or disabling stroke and other adverse events and hemodynamic findings at 5 years. An independent clinical event committee adjudicated all serious adverse events and an independent echocardiographic core laboratory evaluated all echocardiograms at 5 years.ResultsA total of 1660 individuals underwent an attempted TAVR (n = 864) or surgical (n = 796) procedure. The mean (SD) age was 79.8 (6.2) years, 724 (43.6%) were female, and the mean (SD) Society of Thoracic Surgery Predicted Risk of Mortality score was 4.5% (1.6%). At 5 years, the rates of death or disabling stroke were similar (TAVR, 31.3% vs surgery, 30.8%; hazard ratio, 1.02 [95% CI, 0.85-1.22]; P = .85). Transprosthetic gradients remained lower (mean [SD], 8.6 [5.5] mm Hg vs 11.2 [6.0] mm Hg; P &amp;lt; .001) and aortic valve areas were higher (mean [SD], 2.2 [0.7] cm2 vs 1.8 [0.6] cm2; P &amp;lt; .001) with TAVR vs surgery. More patients had moderate/severe paravalvular leak with TAVR than surgery (11 [3.0%] vs 2 [0.7%]; risk difference, 2.37% [95% CI, 0.17%- 4.85%]; P = .05). New pacemaker implantation rates were higher for TAVR than surgery at 5 years (289 [39.1%] vs 94 [15.1%]; hazard ratio, 3.30 [95% CI, 2.61-4.17]; log-rank P &amp;lt; .001), as were valve reintervention rates (27 [3.5%] vs 11 [1.9%]; hazard ratio, 2.21 [95% CI, 1.10-4.45]; log-rank P = .02), although between 2 and 5 years only 6 patients who underwent TAVR and 7 who underwent surgery required a reintervention.Conclusions and RelevanceAmong intermediate-risk patients with symptomatic severe aortic stenosis, major clinical outcomes at 5 years were similar for TAVR and surgery. TAVR was associated with superior hemodynamic valve performance but also with more paravalvular leak and valve reinterventions.