Cerebral Autoregulation Correlation With Outcomes and Spreading Depolarization in Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Delayed cerebral ischemia remains one of the principal therapeutic targets after aneurysmal subarachnoid hemorrhage. While large vessel vasospasm may contribute to ischemia, increasing evidence suggests that physiological impairment through disrupted impaired cerebral autoregulation (CA) and spreading depolarizations (SDs) also contribute to delayed cerebral ischemia and poor neurological outcome. This study seeks to explore the intermeasure correlation of different measures of CA, as well as correlation with SD and neurological outcome. METHODS: Simultaneous measurement of 7 continuous indices of CA was calculated in 19 subjects entered in a prospective study of SD in aneurysmal subarachnoid hemorrhage undergoing surgical aneurysm clipping. Intermeasure agreement was assessed, and the association of each index with modified Rankin Scale score at 90 days and occurrence of SD was assessed. RESULTS: There were 4102 hours of total monitoring time across the 19 subjects. In time-resolved assessment, no CA measures demonstrated significant correlation; however, most demonstrate significant correlation averaged over 1 hour. Pressure reactivity (PRx), oxygen reactivity, and oxygen saturation reactivity were significantly correlated with modified Rankin Scale score at 90 days. PRx and oxygen reactivity also were correlated with the occurrence of SD events. Across multiple CA measure reactivity indices, a threshold between 0.3 and 0.5 was most associated with intervals containing SD. CONCLUSIONS: Different continuous CA indices do not correlate well with each other on a highly time-resolved basis, so should not be viewed as interchangeable. PRx and oxygen reactivity are the most reliable indices in identifying risk of worse outcome in patients with aneurysmal subarachnoid hemorrhage undergoing surgical treatment. SD occurrence is correlated with impaired CA across multiple CA measurement techniques and may represent the pathological mechanism of delayed cerebral ischemia in patients with impaired CA. Optimization of CA in patients with aneurysmal subarachnoid hemorrhage may lead to decreased incidence of SD and improved neurological outcomes. Future studies are needed to evaluate these hypotheses and approaches.

Depressed right ventricular systolic function in heart failure due to constrictive pericarditis.

AIMS: Heart failure in constrictive pericarditis (CP) is attributed to impaired biventricular diastolic filling. However, diseases that cause CP due to myocardial infiltration and fibrosis can also impair biventricular systolic function (sf) and contribute to heart failure. This study of patients with CP examined biventricular sf and the effect of myocardial infiltration by pericardial diseases and the resulting fibrosis on ventricular sf. METHODS AND RESULTS: Histopathologic examinations of right ventricular (RV) and left ventricular (LV) myocardia and pericardia were performed on three autopsied hearts of patients with pericardial diseases. Additionally, in 40 adults with clinical heart failure and 40 healthy adults (controls), sf of both ventricles was examined by echocardiography, including strain measurements, and biventricular diastolic filling and pulmonary artery pressures were assessed by cardiac catheterization. Cardiac histopathology indicated thickening of the pericardium with fibrosis, disease infiltrating the myocardium, greater infiltration of the RV than the LV, and an association of pericardial thickness with myocardial infiltrations. Functional analysis indicated that RVsf was impaired on all echo indices, including strain measurement, but LVsf was preserved. CONCLUSIONS: Diseases causing CP are not restricted to the pericardium but also infiltrate the biventricular myocardium and affect the thin-walled RV more than the thick-walled LV, resulting in depressed RVsf. The present results help explain clinical heart failure in the presence of restricted diastolic filling in CP. Depression of RVsf due to progression of fibrosis in the RV myocardium may increase the risk of delayed pericardiectomy.

Copper-catalyzed Hiyama coupling of (hetero)aryltriethoxysilanes with (hetero)aryl iodides.

A Cu(I)-catalyzed Hiyama coupling was achieved, which proceeds in the absence of an ancillary ligand for aryl-heteroaryl and heteroaryl-heteroaryl couplings. A P,N-ligand is required to obtain the best product yields for aryl-aryl couplings. In addition to facilitating transmetalation, CsF is also found to function as a stabilizer of the [CuAr] species, potentially generated as an intermediate after transmetalation of aryltriethoxysilanes with Cu(I)-catalysts in the absence of ancillary ligands.