Differential effects of group III metabotropic glutamate receptors on spontaneous inhibitory synaptic currents in spine-innervating double bouquet and parvalbumin-expressing dendrite-targeting GABAergic interneurons in human neocortex.

Diverse neocortical GABAergic neurons specialize in synaptic targeting and their effects are modulated by presynaptic metabotropic glutamate receptors (mGluRs) suppressing neurotransmitter release in rodents, but their effects in human neocortex are unknown. We tested whether activation of group III mGluRs by L-AP4 changes GABAA receptor-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) in 2 distinct dendritic spine-innervating GABAergic interneurons recorded in vitro in human neocortex. Calbindin-positive double bouquet cells (DBCs) had columnar "horsetail" axons descending through layers II-V innervating dendritic spines (48%) and shafts, but not somata of pyramidal and nonpyramidal neurons. Parvalbumin-expressing dendrite-targeting cell (PV-DTC) axons extended in all directions innervating dendritic spines (22%), shafts (65%), and somata (13%). As measured, 20% of GABAergic neuropil synapses innervate spines, hence DBCs, but not PV-DTCs, preferentially select spine targets. Group III mGluR activation paradoxically increased the frequency of sIPSCs in DBCs (to median 137% of baseline) but suppressed it in PV-DTCs (median 92%), leaving the amplitude unchanged. The facilitation of sIPSCs in DBCs may result from their unique GABAergic input being disinhibited via network effect. We conclude that dendritic spines receive specialized, diverse GABAergic inputs, and group III mGluRs differentially regulate GABAergic synaptic transmission to distinct GABAergic cell types in human cortex.

Multiple surgical resections for progressive IDH wildtype glioblastoma-is it beneficial?

PURPOSE: The role of repeat resection for recurrent glioblastoma (rGB) remains equivocal. This study aims to assess the overall survival and complications rates of single or repeat resection for rGB. METHODS: A single-centre retrospective review of all patients with IDH-wildtype glioblastoma managed surgically, between January 2014 and January 2022, was carried out. Patient survival and factors influencing prognosis were analysed, using Kaplan-Meier and Cox regression methods. RESULTS: Four hundred thirty-two patients were included, of whom 329 underwent single resection, 83 had two resections and 20 patients underwent three resections. Median OS (mOS) in the cohort who underwent a single operation was 13.7 months (95% CI: 12.7-14.7 months). The mOS was observed to be extended in patients who underwent second or third-time resection, at 22.9 months and 44.7 months respectively (p < 0.001). On second operation achieving > 95% resection or residual tumour volume of < 2.25 cc was significantly associated with prolonged survival. There was no significant difference in overall complication rates between primary versus second (p = 0.973) or third-time resections (p = 0.312). The use of diffusion tensor imaging (DTI) guided resection was associated with reduced post-operative neurological deficit (RR 0.37, p = 0.002), as was use of intraoperative ultrasound (iUSS) (RR 0.45, p = 0.04). CONCLUSIONS: This study demonstrates potential prolongation of survival for rGB patients undergoing repeat resection, without significant increase in complication rates with repeat resections. Achieving a more complete repeat resection improved survival. Moreover, the use of intraoperative imaging adjuncts can maximise tumour resection, whilst minimising the risk of neurological deficit.

Prevalence and clinical associations of mitral and aortic regurgitation in patients with aortic stenosis.

BACKGROUND: Most guidelines directing clinicians to manage valve disease are directed at single valve lesions. Limited data exists to direct our understanding of how concomitant valve disease impacts the left ventricle (LV). METHODS: We identified 2817 patients with aortic stenosis (AS) from the echocardiography laboratory database between September 2012 and June 2018 who had a LV ejection fraction (EF) ≥50%. LV mass, LV mass index, LV systolic pressure (systolic blood pressure + peak aortic gradient). Covariates were collected from the electronic medical record. Multi-variate analysis of covariance was used to generate adjusted comparisons. RESULTS: Our population was 66% female, 17% African-American with a mean age of 65 years. Of note, 7.3% were noted to have significant (moderate/severe) aortic regurgitation (AR), and 11% had significant (moderate/severe) mitral regurgitation (MR). Adjusting for covariates at different levels, significant MR had a much stronger association with heart failure compared to those with significant AR (p < .001 vs. p = .313, respectively) at all levels of adjustment. Both significant mitral and AR exhibited an association with increasing left ventricular mass, even with adjustment for baseline demographics and clinical features (p < .001 vs. p = .007, respectively). CONCLUSION: In patients with AS, 16% also experience at least moderate MR or AR. Further, significant MR has a stronger association with heart failure than significant AR, even though both increase left ventricular mass. Those with moderate AS and significant MR or AR experience similar or higher levels of heart failure compared to severe AS without regurgitation. Mixed valve disease merits further studies to direct longitudinal management.

Tonic GABAA Receptor-Mediated Currents of Human Cortical GABAergic Interneurons Vary Amongst Cell Types.

Persistent anion conductances through GABAA receptors (GABAARs) are important modulators of neuronal excitability. However, it is currently unknown how the amplitudes of these currents vary among different cell types in the human neocortex, particularly among diverse GABAergic interneurons. We have recorded 101 interneurons in and near layer 1 from cortical tissue surgically resected from both male and female patients, visualized 84 of them and measured tonic GABAAR currents in 48 cells with an intracellular [Cl-] of 65 mm and in the presence of 5 µm GABA. We compare these tonic currents among five groups of interneurons divided by firing properties and four types of interneuron defined by axonal distributions; rosehip, neurogliaform, stalked-bouton, layer 2-3 innervating and a pool of other cells. Interestingly, the rosehip cell, a type of interneuron only described thus far in human tissue, and layer 2-3 innervating cells exhibit larger tonic currents than other layer 1 interneurons, such as neurogliaform and stalked-bouton cells; the latter two groups showing no difference. The positive allosteric modulators of GABAARs allopregnanolone and DS2 also induced larger current shifts in the rosehip and layer 2-3 innervating cells, consistent with higher expression of the δ subunit of the GABAAR in these neurons. We have also examined how patient parameters, such as age, seizures, type of cancer and anticonvulsant treatment may alter tonic inhibitory currents in human neurons. The cell type-specific differences in tonic inhibitory currents could potentially be used to selectively modulate cortical circuitry.SIGNIFICANCE STATEMENT Tonic currents through GABAA receptors (GABAARs) are a potential therapeutic target for a number of neurologic and psychiatric conditions. Here, we show that these currents in human cerebral cortical GABAergic neurons display cell type-specific differences in their amplitudes which implies differential modulation of their excitability. Additionally, we examine whether the amplitudes of the tonic currents measured in our study show any differences between patient populations, finding some evidence that age, seizures, type of cancer, and anticonvulsant treatment may alter tonic inhibition in human tissue. These results advance our understanding of how pathology affects neuronal excitability and could potentially be used to selectively modulate cortical circuitry.

Frequent Assembly of Chimeric Complexes in the Protein Interaction Network of an Interspecies Yeast Hybrid.

Hybrids between species often show extreme phenotypes, including some that take place at the molecular level. In this study, we investigated the phenotypes of an interspecies diploid hybrid in terms of protein-protein interactions inferred from protein correlation profiling. We used two yeast species, Saccharomyces cerevisiae and Saccharomyces uvarum, which are interfertile, but yet have proteins diverged enough to be differentiated using mass spectrometry. Most of the protein-protein interactions are similar between hybrid and parents, and are consistent with the assembly of chimeric complexes, which we validated using an orthogonal approach for the prefoldin complex. We also identified instances of altered protein-protein interactions in the hybrid, for instance, in complexes related to proteostasis and in mitochondrial protein complexes. Overall, this study uncovers the likely frequent occurrence of chimeric protein complexes with few exceptions, which may result from incompatibilities or imbalances between the parental proteomes.

Newer Drugs to Reduce High Blood Pressure and Mitigate Hypertensive Target Organ Damage.

PURPOSE OF REVIEW: This review aims to investigate the blood pressure (BP)-lowering effects of emerging drugs developed to treat diabetic kidney disease and heart failure (HF). We summarize the potential pathophysiological mechanisms responsible for mitigating hypertensive target organ damage and evaluating the available clinical data on these newer drugs. RECENT FINDINGS: Nonsteroidal dihydropyridine-based mineralocorticoid receptor antagonists (MRAs), dual angiotensin II receptor-neprilysin inhibitors (valsartan with sacubitril), sodium-glucose cotransporter 2 inhibitors (SGLT2i), and soluble guanylate cyclase stimulators are new classes of chemical agents that have distinct mechanisms of action and have been shown to be effective for the treatment of cardiovascular (CV) disease (CVD), HF, and type 2 diabetes mellitus (T2D). These drugs can be used either alone or in combination with other antihypertensive and CV drugs. Among these, SGLT2i and valsartan with sacubitril offer new avenues to reduce CVD mortality. SGLT2i have a mild-to-moderate effect on BP lowering with a favorable effect on CV and renal hemodynamics and have been shown to produce a significant reduction in the incidence of major adverse CVD events (as monotherapy or add-on therapy) compared with controls (placebo or non-SGLT2i treatment). Most of the participants in these studies had hypertension (HTN) at baseline and were receiving antihypertensive therapy, including renin-angiotensin system blockers. The combination of valsartan with sacubitril also lowers BP in the short term and has demonstrated a striking reduction in CVD mortality and morbidity in HF patients with a reduced left ventricular ejection fraction. If widely adopted, these novel therapeutic agents hold significant promise for reducing the public health burden posed by HTN and CVD. Based on the results of several clinical trials and considering the high prevalence of HTN and T2D, these new classes of agents have emerged as powerful therapeutic tools in managing and lowering the BP of patients with diabetic kidney disease and HF.

Hypertension Across a Woman's Life Cycle.

PURPOSE OF REVIEW: We reviewed the effects of hypertension and the means to prevent and treat it across the spectrum of a woman's lifespan and identified gaps in sex-specific mechanisms contributing to hypertension in women that need to be addressed. RECENT FINDINGS: Hypertension continues to be an important public health problem for women across all life stages from adolescence through pregnancy, menopause, and older age. There remain racial, ethnic, and socioeconomic differences in hypertension rates not only overall but also between the sexes. Blood pressure cutoffs during pregnancy have not been updated to reflect the 2017 ACC/AHA changes due to a lack of data. Additionally, the mechanisms behind hypertension development in menopause, including sex hormones and genetic factors, are not well understood. In the setting of increasing inactivity and obesity, along with an aging population, hypertension rates are increasing in women. Screening and management of hypertension throughout a women's lifespan are necessary to reduce the burden of cardiovascular disease, and further research to understand sex-specific hypertension mechanisms is needed.

Diffusion tractography for awake craniotomy: accuracy and factors affecting specificity.

INTRODUCTION: Despite evidence of correspondence with intraoperative stimulation, there remains limited data on MRI diffusion tractography (DT)'s sensitivity to predict morbidity after neurosurgical oncology treatment. Our aims were: (1) evaluate DT against subcortical stimulation mapping and performance changes during and after awake neurosurgery; (2) evaluate utility of early post-operative DT to predict recovery from post-surgical deficits. METHODS: We retrospectively reviewed our first 100 awake neurosurgery procedures using DT- neuronavigation. Intra-operative stimulation and performance outcomes were assessed to classify DT predictions for sensitivity and specificity calculations. Post-operative DT data, available in 51 patients, were inspected for tract damage. RESULTS: 91 adult brain tumor patients (mean 49.2 years, 43 women) underwent 100 awake surgeries with subcortical stimulation between 2014 and 2019. Sensitivity and specificity of pre-operative DT predictions were 92.2% and 69.2%, varying among tracts. Post-operative deficits occurred after 41 procedures (39%), but were prolonged (> 3 months) in only 4 patients (4%). Post-operative DT in general confirmed surgical preservation of tracts. Post-operative DT anticipated complete recovery in a patient with supplementary motor area syndrome, and indicated infarct-related damage to corticospinal fibers associated with delayed, partial recovery in a second patient. CONCLUSIONS: Pre-operative DT provided very accurate predictions of the spatial location of tracts in relation to a tumor. As expected, however, the presence of a tract did not inform its functional status, resulting in variable DT specificity among individual tracts. While prolonged deficits were rare, DT in the immediate post-operative period offered additional potential to monitor neurological deficits and anticipate recovery potential.

Optimizing The Management of Obese HFpEF Phenotype: Can We Mind Both The Heart and The Kidney?

The adverse prognostic implications of significant renal dysfunction during treatment of acute decompensated heart failure (HF) in patients with obese HF and preserved ejection fraction (HFpEF) provide strong rationale for development of therapeutic strategies that enhance decongestion while preserving renal function in this cohort. The combination of preload sensitivity, intrinsic renal dysfunction related to obesity, glomerular hyperfiltration, reversible renal hypoperfusion (poor renal arterial perfusion and renal venous congestion), and decreased systemic vascular resistance in obesity may predispose patients to renal hemodynamic compromise during diuresis. Thus, serum creatinine increase should not be evaluated in isolation but rather considered in the context of the entire clinical picture in patients with obese HFpEF.

Obstructive coronary artery disease with a coronary artery calcium score of 0: A case report.

Coronary artery calcium (CAC) scoring has emerged as a useful tool in identifying patients who may benefit from more aggressive risk factor modification and for prognostication. Although a CAC score of 0 is associated with a very low prevalence of obstructive epicardial coronary artery disease and low event rates, it can also provide a false sense of reassurance. We present a case of a 39-year-old woman with a CAC score of 0 obtained as part of a coronary computerized tomography angiography study that was ultimately found to have significant left anterior descending artery disease requiring percutaneous coronary intervention and a stent.

Impact of anatomical variations of the left ventricular outflow tract on stroke volume calculation by Doppler echocardiography in aortic stenosis.

BACKGROUND: Accurate calculation of stroke volume (SV) by Doppler echocardiography is important for the assessment of aortic stenosis (AS), which may be impacted by anatomical variations of left ventricular outflow tract (LVOT). METHODS: Patients with AS (n = 64) were studied using computed tomography (CT) and transthoracic echocardiography (TTE). Anatomical variations of LVOT areas were measured at (a) the aortic annulus (Aa ); (b) 5 mm (A5 ); and (c) 10 mm below the annulus (A10 ) by CT. LVOT diameters were also measured by 2D TTE at these three levels for calculation of LVOT areas. Stroke volumes (SV) were calculated using continuity equation. The impacts of anatomical variations of LVOT on SV calculation were evaluated. RESULTS: Anatomical LVOT area increased from Aa to A10 (5.0 ± 0.9 cm2 vs 5.8 ± 1.9 cm2 , P < .01). Differences between TTE-calculated LVOT areas and anatomical areas were most significant at A10 due to elongation of mediolateral diameters with variable changes in anteroposterior diameters (5.8 ± 1.9 cm2 vs 3.4 ± 1.1 cm2 , P < .001). Although mean calculated SV by TTE was not significant at different LVOT levels (Aa 69 ± 22 mL, vs A5 66 ± 21 mL, vs A10 66 ± 28 ± 22 mL, P > .05), the most significant variations in individuals were at A10 levels (ΔSV: 8.2 ± 6.4 mL, 12 ± 9%). CONCLUSION: Variations of LVOT anatomy in individuals with AS significantly impact the SV calculated by Doppler echocardiography. These features should be taken into account for AS diagnosis and a clinical decision-making for intervention.

Electrocardiographic myocardial injury and stroke mortality in the general population.

BACKGROUND: Recent evidence suggests a link between myocardial infarction and stroke risk, but it is unclear whether such risk exists with electrocardiographic myocardial injury in otherwise healthy individuals. Therefore, we explored the association of myocardial injury with stroke mortality in participants free of cardiovascular disease. METHODS: This analysis included 6017 participants (58.4 ± 13.4 years, 54.1% women, 50.3% white) from the Third National Health and Nutrition Examination Survey. Cardiac infarction/injury score (CIIS), a weighted scoring system composed of several electrocardiographic waveform components related to myocardial injury and ischemia, was used to define myocardial injury. Stroke mortality was ascertained using the National Death Index during follow-up. Multivariable adjusted Cox proportional hazard analysis was used to examine the association between baseline myocardial injury and risk of stroke mortality. RESULTS: Over a median follow-up of 14 years, 152 stroke deaths occurred. Stroke mortality was more common in those with than those without myocardial injury (3.8% vs. 2.1%, respectively; p = 0.0003). In a model adjusted for potential confounders, the myocardial injury was associated with a 44% increased risk of stroke mortality (HR (95%CI):1.44(1.02-2.03)). In a similar model, each 1 CIIS score point increase was associated with a 2% increase in the risk of stroke mortality (HR (95%CI):1.02 (1.00-1.04), p = 0.01). CONCLUSIONS: Electrocardiographic myocardial injury in cardiovascular disease-free adults is associated with an increased risk of stroke mortality suggesting a potential link between asymptomatic myocardial injury and risk of cardiac thromboembolism. Whether screening and management of myocardial injury would reduce such risk requires further investigation.

Binding deficits in visual short-term memory in patients with temporal lobe lobectomy.

Classical views of the medial temporal lobe (MTL) have established that it plays a crucial role in long-term memory (LTM). Here we demonstrate, in a sample of patients who have undergone anterior temporal lobectomy for the treatment of pharmacoresistant epilepsy, that the MTL additionally plays a specific, causal role in short-term memory (STM). Patients (n=22) and age-matched healthy control participants (n=26) performed a STM task with a sensitive continuous report measure. This paradigm allowed us to examine recall memory for object identity, location and object-location binding, independently on a trial-by-trial basis. Our findings point to a specific involvement of MTL in object-location binding, but, crucially, not retention of either object identity or location. Therefore the MTL appears to perform a specific computation: binding disparate features that belong to a memory. These results echo findings from previous studies, which have identified a role for the MTL in relational binding for LTM, and support the proposal that MTL regions perform such a function for both STM and LTM, independent of the retention duration. Furthermore, these findings and the methodology employed here may provide a simple, sensitive and clinically valuable means to test memory dysfunuction in MTL disorders.

Preventing Heart Failure by Treating Systolic Hypertension: What Does the SPRINT Add?

PURPOSE OF REVIEW: Previous trials definitively established that lowering systolic blood pressure (BP) to 140 mmHg prevented heart failure (HF) exacerbations, but the potential benefits and risks of further BP reduction remain unclear due to a paucity of trial-based data. RECENT FINDINGS: A recent secondary analysis of the Systolic Blood Pressure Intervention Trial (SPRINT) found that in older, high-risk, non-diabetic participants with systolic hypertension, a BP treatment target < 120 mmHg resulted in a 36% lower rate of acute decompensated HF as compared with a BP target < 140 mmHg. Those participants with incident HF had a 26-fold increased risk of subsequent cardiovascular events and death. Based in part on the SPRINT results, the 2017 American Heart Association/American College of Cardiology/HF Society Guideline for the Management of HF acknowledged that targeting a significant reduction in BP in those at increased risk for cardiovascular disease is a novel risk-based strategy to prevent HF. SPRINT redefines systolic BP target goals in older, high-risk patients and provides a key opportunity for preventing HF in this patient group.

A comparison of 2-hydroxyglutarate detection at 3 and 7 T with long-TE semi-LASER.

Abnormally high levels of the 'oncometabolite' 2-hydroxyglutarate (2-HG) occur in many grade II and III gliomas, and correlate with mutations in the genes of isocitrate dehydrogenase (IDH) isoforms. In vivo measurement of 2-HG in patients, using magnetic resonance spectroscopy (MRS), has largely been carried out at 3 T, yet signal overlap continues to pose a challenge for 2-HG detection. To combat this, several groups have proposed MRS methods at ultra-high field (≥7 T) where theoretical increases in signal-to-noise ratio and spectral resolution could improve 2-HG detection. Long echo time (long-TE) semi-localization by adiabatic selective refocusing (semi-LASER) (TE = 110 ms) is a promising method for improved 2-HG detection in vivo at either 3 or 7 T owing to the use of broad-band adiabatic localization. Using previously published semi-LASER methods at 3 and 7 T, this study directly compares the detectability of 2-HG in phantoms and in vivo across nine patients. Cramér-Rao lower bounds (CRLBs) of 2-HG fitting were found to be significantly lower at 7 T (6 ± 2%) relative to 3 T (15 ± 7%) (p = 0.0019), yet were larger at 7 T in an IDH wild-type patient. Although no increase in SNR was detected at 7 T (77 ± 26) relative to 3 T (77 ± 30), the detection of 2-HG was greatly enhanced through an improved spectral profile and increased resolution at 7 T. 7 T had a large effect on pairwise fitting correlations between γ-aminobutyric acid (GABA) and 2-HG (p = 0.004), and resulted in smaller coefficients. The increased sensitivity for 2-HG detection using long-TE acquisition at 7 T may allow for more rapid estimation of 2-HG (within a few spectral averages) together with other associated metabolic markers in glioma.

Cardiac magnetic resonance in cardiac angiosarcoma.

BACKGROUND: While echocardiography is effective for initial identification of anatomic location, magnetic resonance imaging (MRI) is a more advantageous modality for delineating tumor expanse, spread, and blood supply preoperatively. Emerging patterns may even help generate a specific diagnosis prior to biopsy and histopathology. CASE PRESENTATION: Our case of a 67-year-old male referred for cardiac magnetic resonance to further evaluate a cardiac mass highlights the sophisticated level of data which can be collected. Our case highlights the perfusion related findings associated with cardiac angiosarcoma. CONCLUSION: In this case, we present the diagnosis of right atrial cardiac angiosarcoma by multiple imaging modalities including MRI and subsequent angiography, allowing for prompt surgical intervention and initiation of adjuvant therapy that resulted in a survival time of 19 months.

Thalamo-Cortical Disruption Contributes to Short-Term Memory Deficits in Patients with Medial Temporal Lobe Damage.

Short-term (STM) and long-term memory (LTM) have largely been considered as separate brain systems reflecting fronto-parietal and medial temporal lobe (MTL) functions, respectively. This functional dichotomy has been called into question by evidence of deficits on aspects of working memory in patients with MTL damage, suggesting a potentially direct hippocampal contribution to STM. As the hippocampus has direct anatomical connections with the thalamus, we tested the hypothesis that damage to thalamic nuclei regulating cortico-cortical interactions may contribute to STM deficits in patients with hippocampal dysfunction. We used diffusion-weighted magnetic resonance imaging-based tractography to identify anatomical subdivisions in patients with MTL epilepsy. From these, we measured resting-state functional connectivity with detailed cortical divisions of the frontal, temporal, and parietal lobes. Whereas thalamo-temporal functional connectivity reflected LTM performance, thalamo-prefrontal functional connectivity specifically predicted STM performance. Notably, patients with hippocampal volume loss showed thalamic volume loss, most prominent in the pulvinar region, not detected in patients with normal hippocampal volumes. Aberrant thalamo-cortical connectivity in the epileptic hemisphere was mirrored in a loss of behavioral association with STM performance specifically in patients with hippocampal atrophy. These findings identify thalamo-cortical disruption as a potential mechanism contributing to STM deficits in the context of MTL damage.

Aberrant functional connectivity in dissociable hippocampal networks is associated with deficits in memory.

In the healthy human brain, evidence for dissociable memory networks along the anterior-posterior axis of the hippocampus suggests that this structure may not function as a unitary entity. Failure to consider these functional divisions may explain diverging results among studies of memory adaptation in disease. Using task-based and resting functional MRI, we show that chronic seizures disrupting the anterior medial temporal lobe (MTL) preserve anterior and posterior hippocampal-cortical dissociations, but alter signaling between these and other key brain regions. During performance of a memory encoding task, we found reduced neural activity in human patients with unilateral temporal lobe epilepsy relative to age-matched healthy controls, but no upregulation of fMRI signal in unaffected hippocampal subregions. Instead, patients showed aberrant resting fMRI connectivity within anterior and posterior hippocampal-cortical networks, which was associated with memory decline, distinguishing memory-intact from memory-impaired patients. Our results highlight a critical role for intact hippocampo-cortical functional communication in memory and provide evidence that chronic injury-induced functional reorganization in the diseased MTL is behavioral inefficient.

Prediabetes and the association with unrecognized myocardial infarction in the multi-ethnic study of atherosclerosis.

BACKGROUND: With one-quarter of initial myocardial infarctions (MI) being unrecognized MI (UMI), recognition is critical to minimize further cardiovascular risk. Diabetes mellitus is an established risk factor for UMI. If impaired fasting glucose (IFG) also increased the risk for UMI, it would represent a significant public health challenge due to the rapid worldwide increase in IFG prevalence. We compared participants with IFG to those with normal fasting glucose (NFG) to determine if IFG was associated with UMIs. METHODS: We performed cross-sectional analyses from the MESA, a population-based cohort study. There were 6,814 participants recruited during July 2000 to September 2002 from the general community at 6 field sites. After excluding those with diabetes mellitus or missing variables, 5,885 participants were included. At baseline, there were 4,955 participants with NFG and 930 participants with IFG. The main outcome was an UMI defined by the presence of pathological Q waves or minor Q waves with ST-T abnormalities on initial 12-lead electrocardiogram. Logistic regression was used to generate crude ORs and adjust for covariates. RESULTS: There was a higher prevalence of UMI in those with IFG compared with those with NFG [3.5% (n = 72) vs 1.4% (n = 30)]. After adjustment for multiple risk factors, there was a higher odds of an UMI among those with IFG compared with those with NFG [OR: 1.60 (95% CI: 1.0-2.5); P = .048]. CONCLUSIONS: Impaired fasting glucose is associated with unrecognized myocardial infarctions in a multi-ethnic population free of baseline cardiovascular disease.

Mechanism of decreased sensitivity of dobutamine associated left ventricular wall motion analyses for appreciating inducible ischemia in older adults.

BACKGROUND: Dobutamine associated left ventricular (LV) wall motion analyses exhibit reduced sensitivity for detecting inducible ischemia in individuals with increased LV wall thickness. This study was performed to better understand the mechanism of this reduced sensitivity in the elderly who often manifest increased LV wall thickness and risk factors for coronary artery disease. METHODS: During dobutamine cardiovascular magnetic resonance (DCMR) stress testing, we assessed rate pressure product (RPP), aortic pulse wave velocity (PWV), LV myocardial oxygen demand (pressure volume area, PVA, mass, volumes, concentricity, and the presence of wall motion abnormalities (WMA) and first pass gadolinium enhanced perfusion defects (PDs) indicative of ischemia in 278 consecutively recruited individuals aged 69 ± 8 years with pre-existing or known risk factors for coronary artery disease. Each variable was assessed independently by personnel blinded to participant identifiers and analyses of other DCMR or hemodynamic variables. RESULTS: Participants were 80% white, 90% hypertensive, 43% diabetic and 55% men. With dobutamine, 60% of the participants who exhibited PDs had no inducible WMA. Among these participants, myocardial oxygen demand was lower than that observed in those who had both wall motion and perfusion abnormalities suggestive of ischemia (p = 0.03). Relative to those with PDs and inducible WMAs, myocardial oxygen demand remained different in these individuals with PDs without an inducible WMA after accounting for LV afterload and contractility (p = 0.02 and 0.03 respectively), but not after accounting for either LV stress related end diastolic volume index (LV preload) or resting concentricity (p = 0.31-0.71). CONCLUSIONS: During dobutamine stress testing, elderly patients experience increased LV concentricity and declines in LV preload and myocardial oxygen demand, all of which are associated with an absence of inducible LV WMAs indicative of myocardial ischemia. These findings provide insight as to why dobutamine associated wall motion analyses exhibit reduced sensitivity for identifying inducible ischemia in elderly. TRIAL REGISTRATION: This study was registered with Clinicaltrials.gov (NCT00542503).