In non-contiguous allocation, a job request can be split into smaller parts that are allocated possibly non-adjacent free sub-meshes rather than always waiting until a single sub-mesh of the requested size and shape is available. Lifting the contiguity condition is expected to reduce processor fragmentation and increase system utilization. However, the distances traversed by messages can be long, and as a result the communication overhead, especially contention, is likely to increase. The extra communication overhead depends on how the allocation request is partitioned and assigned to free sub-meshes. In this paper, a new non-contiguous processor allocation strategy, referred to as Compacting Non-Contiguous Processor Allocation Strategy (CNCPA), is suggested for the 2D mesh multicomputers. In the proposed strategy, a job is compacted into free locations. The selection of the free locations has for goal leaving large free sub-meshes in the system. To evaluate the performance improvement achieved by the proposed strategy and compare it against well-known existing non-contiguous allocation strategies, the authors conducted extensive simulation experiments. The results show that the proposed strategy can improve performance in terms of job turnaround times and system utilization.
The Efficacy of Cardiac Myosin Inhibitors Versus Placebo in Patients with Symptomatic Hypertrophic Cardiomyopathy. Introduction: Given the interplay between hypertrophic cardiomyopathy, elevated resting LVOT gradients (≥ 50 mm Hg) and heart failure and cardiovascular death, cardiac myosin inhibitors have recently emerged as a promising novel therapy to improve HCM-related outcomes by regulating myocardial relaxation and contractility, and thereby reducing intracavitary gradients. Methods: We performed a literature search using PubMed, Embase, and Cochrane Library from inception through May 2022 to assess the impact of novel cardiac myosin inhibitors (Mavacamten and Aficamten) on resting and Valsalva LVOT gradients and functional capacity in patients with symptomatic hypertrophic cardiomyopathy. The co-primary outcomes were mean percent change from baseline in resting LVOT gradient and Valsalva LVOT gradient, as well as patients achieving NYHA Class Improvement ≥ 1. Secondary outcomes included mean percent change from baseline NT ProBNP, Troponin I, and LVEF. Results: 4 studies (all randomized-control trials, including 3 Mavacamten-focused and 1 Aficamten-focused trials) involving 463 patients were included in the meta-analysis. Compared to patients receiving placebo, the cardiac myosin inhibitor group demonstrated statistically significant differences in baseline percent change in mean resting LVOT gradient (MD -62.48, CI -65.44, -59.51, p <0.00001) and Valsalva LVOT gradient (MD -54.21, CI -66.05, -42.36, p <0.00001), as well as number of patients achieving NYHA Class Improvement ≥ 1 (OR 3.43, CI 1.90, 6.20, p <0.0001). Regarding secondary outcomes, the intervention group demonstrated statistically significant reductions in meant percent change from baseline in NT-proBNP (MD -69.41, CI-87.06, -51.75, p < 0.00001), Troponin I (MD, -44.19, CI -50.59, -37.78, p < 0.00001), and LVEF (MD -6.31, CI -10.35, -2.27, p = 0.002). Conclusion: The use of cardiac myosin inhibitors in patients with symptomatic hypertrophic cardiomyopathy may confer both clinical and sympatomatic benefits, at the possible expense of LV ejection fraction. Further trials with large sample sizes are needed to confirm our findings.
Hypothesis: Transcatheter aortic valve replacement (TAVR) serves as a less-invasive treatment option for high-risk patients with severe aortic stenosis. Given the coexistence of obstructive coronary artery disease in patients with high-grade aortic stenosis (estimated to be 40-75%), there is inconsistent clinical data regarding potential mortality benefits of paired percutaneous coronary intervention (PCI) with TAVR procedures. Methods: We performed a literature search using PubMed, Embase, and Cochrane Library from inception through April 2022 to assess the mortality impact of preceding/concomitant PCI in patients undergoing transcatheter aortic valve replacement. The primary outcomes were 30-day all-cause mortality, 30-day cardiovascular mortality, and 6 months-1 year all-cause mortality. Secondary outcomes included 30-day myocardial infarction, stroke, major bleeding/vascular complications, and acute kidney injury. Results: 11 studies (10 retrospective cohort studies, 1 randomized control trial) involving 2791 patients were included in the meta-analysis. Compared to patients undergoing TAVR alone, the TAVR+PCI group showed no significant difference in 30-day all-cause mortality (RR 0.90, CI 0.66, 1.22, p =0.49), 30-day cardiovascular mortality (RR 0.71 CI 0.44, 1.14, p =0.16), or 6 months-1 year all-cause mortality (RR 0.94, CI 0.75, 1.18, p =0.57). Regarding secondary outcomes, 30-day myocardial infarction was higher in the TAVR+PCI group compared to the TAVR group (RR 3.09, CI 1.26, 7.57, p =0.01), while no significant differences were found in rates of 30-day stroke (RR 1.14, CI 0.56, 2.33, p =0.72), major bleeding/vascular complications (RR 1.11, CI 0.79, 1.56, p =0.55), and acute kidney injury (RR 1.07, CI 0.75, 1.54, p =0.71). Conclusion: Concomitant/preceding percutaneous coronary intervention does not confer any additional mortality benefit, and may increase the risk of 30-day myocardial infarction, in patients with high-grade aortic stenosis undergoing transcatheter aortic valve replacement. Further trials with large sample sizes are needed to confirm our findings.
Introduction: Chronic total occlusion (CTO) percutaneous intervention (PCI) is an evolving challenge within interventional cardiology. Anticoagulation during percutaneous intervention remains part of the standard of care for patients undergoing PCI to prevent thrombotic complications peri-procedurally. Unfractionated heparin (UFH) is a commonly used for CTO PCI-related anticoagulation. However, bivalirudin (BV), a synthetic, reversible, direct thrombin inhibitor, has been utilized as an alternative to UFH in CTO patients undergoing PCI. This meta-analysis aims to investigate the efficacy and safety of bivalirudin versus UFH for CTO PCI. Methods: We performed a comprehensive literature search using PubMed, Embase, and Cochrane Library databases through May 2022 for all studies evaluating efficacy and safety of bivalirudin versus UFH in CTO patients undergoing PCI. The primary outcome was mortality. Secondary outcomes were major adverse cardiac events (MACE), major bleeding events, peri-procedure myocardial infarction (MI), in-stent thrombosis, and unplanned revascularization. Pooled risk ratio (RR) and 95% confidence intervals (CIs) were obtained by the Mantel-Haenszel method within a random-effects model. Heterogeneity was assessed by I2 statistic. Results: A total of 5 studies containing 1347 patients with CTO undergoing PCI on anticoagulation (631 BV versus 716 UFH) were included. No significant difference existed between BV and UFH regarding mortality [RR: 0.54 (95% CI: 0.19-1.56); P 0.26 , I2 0%]. Major bleeding events were significantly lower in BV compared with UFH [RR: 0.33 (95% CI: 0.19-0.66); P 0.001, I2 0%]. MACE [RR: 0.75 (95% CI: 0.55-1.00); P 0.05, I2 2%], peri-procedure MI [RR: 0.80 (95% CI: 0.56-1.15); P 0.24, I2 0%], in-stent thrombosis [RR: 0.68 (95% CI: 0.19-2.39); P 0.55, I2 17%] and unplanned revascularization [OR: 0.77 (95% CI: 0.29-2.07); P 0.61, I2 0%] were similar between the two groups. Conclusions: BV seems to be safer than UFH in preventing major bleeding in anticoagulated patients with CTO undergoing PCI; there is no significant difference between groups in terms of mortality, MACE, peri-procedure MI, in-stent thrombosis, or unplanned revascularization. Future randomized controlled trials are needed.
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