Positron Emission Tomography Imaging of Regional Versus Global Myocardial Sympathetic Activity to Improve Risk Stratification in Patients With Ischemic Cardiomyopathy.

BACKGROUND: Current risk assessment approaches fail to identify the majority of patients at risk of sudden cardiac arrest (SCA). Noninvasive imaging of the cardiac sympathetic nervous system using single-photon emission computed tomography and positron emission tomography offers the potential for refining SCA risk assessment. While various [11C]meta-hydroxyephedrine quantification parameters have been proposed, it is currently unknown whether regional denervation or global innervation yields greater SCA risk discrimination. The aim of the study was to determine whether the global innervation parameters yield any independent and additive prognostic value over the regional denervation alone. METHODS: In a post hoc competing-risks analysis of the PAREPET trial (Prediction of Arrhythmic Events With Positron Emission Tomography), we compared global innervation and regional denervation parameters using the norepinephrine analog [11C]meta-hydroxyephedrine for SCA risk discrimination. Patients with ischemic cardiomyopathy (n=174) eligible for an implantable cardioverter-defibrillator for the primary prevention of SCA were recruited into the trial. [11C]meta-hydroxyephedrine uptake and clearance rates were measured to assess global (left ventricle mean) retention index and volume of distribution. Regional defects were quantified as the percentage of the left ventricle having values <75% of the maximum. RESULTS: During a median follow-up of 4.2 years, there were 56 cardiac-related deaths, of which 26 were SCAs. For any given regional denervation volume, there was substantial heterogeneity in global innervation scores. Global retention index and distribution volume did not decrease until regional defects exceeded 40% left ventricle. Global scale parameters, retention index, and distribution volume (area under the curve=0.61, P=0.034, P=0.046, respectively), yielded inferior SCA risk discrimination compared to regional heterogeneity (area under the curve=0.74). CONCLUSIONS: Regional denervation volume has superior cause-specific mortality prediction for SCA versus global parameters of sympathetic innervation. These results have widespread implications for future cardiac sympathetic imaging, which will greatly simplify innervation analysis. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01400334.

The impact of interventions for youth experiencing homelessness on housing, mental health, substance use, and family cohesion: a systematic review.

BACKGROUND: Youth often experience unique pathways into homelessness, such as family conflict, child abuse and neglect. Most research has focused on adult homeless populations, yet youth have specific needs that require adapted interventions. This review aims to synthesize evidence on interventions for youth and assess their impacts on health, social, and equity outcomes. METHODS: We systematically searched Medline, Embase, PsycINFO, and other databases from inception until February 9, 2018 for systematic reviews and randomized controlled trials on youth interventions conducted in high income countries. We screened title and abstract and full text for inclusion, and data extraction were completed in duplicate, following the PRISMA-E (equity) review approach. RESULTS: Our search identified 11,936 records. Four systematic reviews and 18 articles on randomized controlled trials met the inclusion criteria. Many studies reported on interventions including individual and family therapies, skill-building, case management, and structural interventions. Cognitive behavioural therapy led to improvements in depression and substance use, and studies of three family-based therapies reported decreases in substance use. Housing first, a structural intervention, led to improvements in housing stability. Many interventions showed inconsistent results compared to services as usual or other interventions, but often led to improvements over time in both the intervention and comparison group. The equity analysis showed that equity variables were inconsistently measured, but there was data to suggest differential outcomes based upon gender and ethnicity. CONCLUSIONS: This review identified a variety of interventions for youth experiencing homelessness. Promising interventions include cognitive behavioural therapy for addressing depression, family-based therapy for substance use outcomes, and housing programs for housing stability. Youth pathways are often unique and thus prevention and treatment may benefit from a tailored and flexible approach.