Abstract 11629: Multicenter Development and Validation of a Machine Learning Risk Model to Predict Right Ventricular Failure Following Mechanical Circulatory Support: The STOP-RVF Score

Circulation, Volume 146, Issue Suppl_1, Page A11629-A11629, November 8, 2022. Introduction:Existing models predicting right ventricular failure (RVF) after durable left ventricular assist device (LVAD) support are limited due to lack of multicenter validation, absence of intraoperative characteristics, and marginal predictive power. We sought to derive and validate a risk model to predict post-LVAD RVF.Methods:Advanced heart failure (HF) patients (N=798) requiring continuous-flow LVAD were enrolled at the Utah Transplant Affiliated Hospitals (n=477), Inova Heart & Vascular Institute (n=183), and Henry Ford Medical Center (n=138). Baseline clinical and intraoperative characteristics were recorded. The primary outcome was RVF incidence, defined as the need for right VAD (RVAD) or intravenous inotropes for >14 days. Bootstrap imputation and lasso variable selection were used to derive a predictive model which was then validated. A risk calculator was developed classifying patients into risk groups, and survival was compared.Results:Patients were predominantly white (72%), males (84%), aged 56±13 years. Patients in the RVF and non-RVF groups were comparable in terms of sex, age, and LVAD indication, while RVF patients more commonly had a history of systemic hypertension, non-ischemic cardiomyopathy, lower INTERMACS profiles, and more commonly required inotropic or temporary circulatory support pre-LVAD. Overall, 193 (24.2%) patients developed RVF with 109 (56.5%) requiring inotropes and 84 (43.5%) an RVAD. Multivariable predictors for RVF are shown in theFigureand achieved a c-statistic of 0.74 (95% CI: 0.70-0.78). Inclusion of intraoperative characteristics did not improve model performance. Cumulative survival was higher in the minimal risk group compared to low, moderate, and high.Conclusions:The STOP-RVF calculator effectively stratifies the risk for RVF after LVAD support by implementing routinely collected clinical data. It could impact patient selection and peri-operative management of advanced HF patients.

Leggi
Ottobre 2022

Hemorrhagic Stroke in Children and Adults With Sickle Cell Anemia: The Post-STOP Cohort

Stroke, Ahead of Print. BACKGROUND:Hemorrhagic stroke in young patients with sickle cell anemia remains poorly characterized.METHODS:The Post-STOP (Stroke Prevention Trial in Sickle Cell Anemia) retrospective study collected follow-up data on STOP and STOP II clinical trial cohorts. From January 2012 to May 2014, a team of analysts abstracted data from medical records of prior participants (all with sickle cell anemia). Two vascular neurologists reviewed data to confirm hemorrhagic strokes defined as spontaneous intracerebral, subarachnoid, or intraventricular hemorrhage. Incidence rates were calculated using survival analysis techniquesRESULTS:Follow-up data were collected from 2850 of 3835 STOP or STOP II participants. Patients (51% male) were a median of 19.1 (interquartile range, 16.6–22.6) years old at the time of last known status. The overall hemorrhagic stroke incidence rate was 63 per 100 000 person-years (95% CI, 45–87). Stratified by age, the incidence rate per 100 000 person-years was 50 (95% CI, 34–75) for children and 134 (95% CI, 74–243) for adults >18 years. Vascular abnormalities (moyamoya arteriopathy, aneurysm or cavernous malformation) were identified in 18 of 35 patients with hemorrhagic stroke.CONCLUSIONS:The incidence rate of hemorrhagic stroke in patients with sickle cell anemia increases with age. Structural vascular abnormalities such as moyamoya arteriopathy and aneurysms are common etiologies for hemorrhage and screening may be warranted.

Leggi
Ottobre 2022

Cohort profile: Stop the Spread Ottawa (SSO)–a community-based prospective cohort study on antibody responses, antibody neutralisation efficiency and cellular immunity to SARS-CoV-2 infection and vaccination

Purpose
To investigate the robustness and longevity of SARS-CoV-2 immune responses conferred by natural infection and vaccination among priority populations such as immunocompromised individuals and people with post-acute sequelae of COVID-19 in a prospective cohort study (Stop the Spread Ottawa—SSO) in adults living in the Ottawa region. In this paper, we describe the study design, ongoing data collection and baseline characteristics of participants.

Participants
Since October 2020, participants who tested positive for COVID-19 (convalescents) or at high risk of exposure to the virus (under surveillance) have provided monthly blood and saliva samples over a 10-month period. As of 2 November 2021, 1026 adults had completed the baseline survey and 976 had attended baseline bloodwork. 300 participants will continue to provide bimonthly blood samples for 24 additional months (ie, total follow-up of 34 months).

Findings to date
The median age of the baseline sample was 44 (IQR 23, range: 18–79) and just over two-thirds (n=688; 67.1%) were female. 255 participants (24.9%) had a history of COVID-19 infection confirmed by PCR and/or serology. Over 600 participants (60.0%) work in high-risk occupations (eg, healthcare, teaching and transportation). 108 participants (10.5%) reported immunocompromising conditions or treatments at baseline (eg, cancer, HIV, other immune deficiency, and/or use of immunosuppressants).

Future plans
SSO continues to yield rich research potential, given the collection of pre-vaccine baseline data and samples from the majority of participants, recruitment of diverse subgroups of interest, and a high level of participant retention and compliance with monthly sampling. The 24-month study extension will maximise opportunities to track SARS-CoV-2 immunity and vaccine efficacy, detect and characterise emerging variants, and compare subgroup humoral and cellular response robustness and persistence.

Leggi
Settembre 2022