Impact of STEMI Diagnosis and Catheterization Laboratory Activation Systems on Sex- and Age-Based Differences in Treatment Delay.

BACKGROUND: Women and the elderly with ST-elevation myocardial infarction (STEMI) experience longer treatment delays despite prehospital STEMI diagnosis and catheterization laboratory activation systems. It is not known what role specific STEMI referral systems might play in mediating this gap in care. We therefore examined sex- and age-based differences in STEMI treatment delay (TD) in different STEMI activation systems. METHODS: This observational comparative effectiveness study comprised 3 retrospective STEMI cohorts: a traditional hospital-based activation cohort (Cohort 1), an automated "physician-blind" prehospital activation cohort (Cohort 2), and a prehospital activation with real-time physician oversight cohort (Cohort 3). Outcomes of interest included sex and age group (< or ≥ 75 years) differences in suboptimal (> 90 minutes) first medical contact-to-device time (FMC-to-device) within each cohort, as well as independent predictors of suboptimal FMC-to-device and in-hospital mortality across cohorts. RESULTS: Five hundred-sixty STEMI activations were analyzed. In Cohort 1 (n = 179), women and those ≥ 75 were more likely to experience suboptimal FMC-to-device times (78.7% vs 36.4%, P = 0.02 and 85.0% vs 58.3%, < 0.01, respectively). Similar findings were observed in Cohort 3 (n = 109) (53.5% vs 32.9%, 56.5% vs 33.3%, respectively; P = 0.05, for both). In Cohort 2 (n = 272), however, there was no significant age-based difference (30.4% vs 21.7%, P = 0.18), and the gap was numerically lower but still significant for women (32.1% vs 20.1%, P = 0.04). When examining prehospital activation cohorts only, female sex (P = 0.03), off-hours presentation (P < 0.01), and physician oversight (P < 0.01) were independent predictors of longer FMC-to-device times. Age ≥ 75 (P < 0.01), Killip class (P < 0.01), and female sex (P = 0.04) were independently associated with in-hospital mortality. CONCLUSIONS: Automated "physician-blind" STEMI activation was associated with a reduced TD gap in women and the elderly, suggesting possible systemic bias. Appropriately powered confirmatory studies are required, but incorporating automated diagnosis and catheterization laboratory activation may be a solution to treatment gaps in STEMI care.

INTRODUCTION: Les femmes et les personnes présentant ont un infarctus du myocarde avec élévation du segment ST (STEMI) subissent de plus longs retards de traitement en dépit du diagnostic préhospitalier de STEMI et des systèmes d'activation de laboratoires de cathétérisme. On ignore le rôle que pourraient jouer les systèmes d'aiguillage des personnes atteintes de STEMI pour combler cette lacune en matière de soins. Nous avons donc examiné les différences selon le sexe et l'âge dans le retard de traitement du STEMI des différents systèmes d'activation de laboratoire en présence de STEMI. MÉTHODES: La présente étude comparative sur l'efficacité regroupait trois cohortes rétrospectives de STEMI : une cohorte traditionnelle d'activation à l'hôpital (cohorte 1), une cohorte d'activation du laboratoire lors de diagnostic préhospitalier automatisé « à l'insu du médecin ¼ (cohorte 2) et une cohorte d'activation du laboratoire de diagnostic préhospitalier dont la surveillance est assurée par un médecin en temps réel (cohorte 3). Les critères d'intérêt étaient les différences selon le sexe et le groupe d'âge (< ou ≥ 75 ans) dans le taux d'intervalle sous-optimal entre la première prise de contact avec les services médicaux et la pose d'un dispositif (> 90 minutes) au sein de chaque cohorte, ainsi que les prédicteurs indépendants de l'intervalle sous-optimal entre la première prise de contact avec les services médicaux et la pose d'un dispositif et la mortalité à l'hôpital de toutes les cohortes. RÉSULTATS: Cinq cents soixante (560) activations de diagnostic de STEMI ont fait l'objet d'une analyse. Dans la cohorte 1 (n = 179), les femmes et les personnes ≥ 75 ans étaient plus susceptibles de subir des intervalles sous-optimaux entre la première prise de contact avec les services médicaux et la pose d'un dispositif (78,7 % vs 36,4 %, P = 0,02 et 85,0 % vs 58,3 %, < 0,01, respectivement). Nous avons observé des résultats similaires dans la cohorte 3 (n = 109) (53,5 % vs 32,9 %, 56,5 % vs 33,3 %, respectivement ; P = 0,05, pour les deux). Toutefois, dans la cohorte 2 (n = 272), il n'y avait aucune différence significative selon l'âge (30,4 % vs 21,7 %, P = 0,18) et l'écart était numériquement plus faible, mais encore significatif chez les femmes (32,1 % vs 20,1 %, P = 0,04). Lorsque nous examinions seulement les cohortes d'activation du laboratoire lors de diagnostic préhospitalier, le sexe féminin (P = 0,03), la survenue dans les heures creuses (P < 0,01) et la surveillance du médecin (P < 0,01) étaient des prédicteurs indépendants d'intervalles plus longs entre la première prise de contact avec les services médicaux et la pose d'un dispositif. L'âge ≥ 75 ans (P < 0,01), la classification de Killip (P < 0,01) et le sexe féminin (P < 0,04) étaient indépendamment associés à la mortalité à l'hôpital. CONCLUSIONS: L'activation du laboratoire lors de diagnostic automatisé du STEMI « à l'insu du médecin ¼ a été associée à une réduction de l'écart dans le retard de traitement chez les femmes et les personnes âgées. Ceci indique un possible biais systémique. Des études confirmatives d'une puissance suffisante sont nécessaires, mais l'incorporation du diagnostic et de l'activation du laboratoire de cathétérisme atuomatisés peut être une solution aux écarts de traitement dans les soins de STEMI.

Lessons from the Tc-99m shortage: implications of substituting Tl-201 for Tc-99m single-photon emission computed tomography.

BACKGROUND: In 2009, the Chalk River nuclear reactor closed for repairs that led to a critical shortage of technetium-99m (Tc-99m). Several centers used thallium-201 (Tl-201) as an alternative radiotracer for myocardial perfusion imaging. Because Tl-201 is considered by many as a suboptimal radiotracer, we sought to understand the impact of using Tl-201 (during the Tc-99m shortage) on downstream resource utilization. METHODS AND RESULTS: We performed a retrospective study at the Ottawa Heart Institute of 7402 patients (60% men; mean age, 62.6 ± 11.8 years), patients were referred for myocardial perfusion imaging between May 2008 and January 2011 (PRE_Tc-99m [2938 patients]), during (DURING_Tl-201 [2959 patients]), and after (POST_Tc-99m [1505 patients]) the Tc-99m shortage. Patients were followed for 6 months after their index myocardial perfusion imaging to determine subsequent rates of cardiac catheterization or noninvasive imaging. More downstream testing was seen in the Tl-201 cohort (639 [21.4%] patients) than the Tc-99m cohort (537 [12.1%] patients; P<0.001). After adjustment using propensity scores, differences in downstream referral rates were maintained. The downstream investigations resulted in an estimated increase in per-patient costs ($165.22; 95% confidence interval, 153.00-177.42) in the DURING_Tl-201 cohort compared with the Tc-99m cohort ($90.97; 95% confidence interval, 83.42-98.90; P<0.001). As well, the mean effective radiation dose per-patient was higher in DURING_Tl-201 (23.57 mSv; 95% confidence interval, 23.16-23.96) than in Tc-99m (12.92 mSv; 95% confidence interval, 12.55-13.40; P<0.001). CONCLUSIONS: In this single-center study, the use of Tl-201 during the Tc-99m shortage was associated with an increase in downstream testing, cost, and patient radiation exposure, but these findings may not be generalizable to other centers. Although Tl-201 provided a short-term solution to the unexpected Tc-99m shortage, long-term cost-effective solutions should be areas of future study.

Acylation-stimulating protein (ASP)/complement C3adesArg deficiency results in increased energy expenditure in mice.

Acylation-stimulating protein (ASP) acts as a paracrine signal to increase triglyceride synthesis in adipocytes. In mice, C3 (the precursor to ASP) knock-out (KO) results in ASP deficiency and leads to reduced body fat and leptin levels yet they are hyperphagic. In the present study, we investigated the mechanism for this energy repartitioning. Compared with wild-type (WT) mice, male and female C3(-/-) ASP-deficient mice had elevated oxygen consumption (VO2) in both the active (dark) and resting (light) phases of the diurnal cycle: +8.9% males (p < 0.05) +9.4% females (p < 0.05). Increased physical activity (movement) was observed during the dark phase in female but not in male KO animals. Female WT mice moved 16.9 +/- 2.4 m whereas KO mice moved 30.1 +/- 5.4 m, over 12 h, +78.4%, p < 0.05). In contrast, there was no difference in physical activity in male mice, but a repartitioning of dietary fat following intragastric fat administration was noted. This was reflected by increased fatty acid oxidation in liver and muscle in KO mice, with increased UCP2 (inguinal fat) and UCP3 (muscle) mRNA expression (p = 0.005 and 0.036, respectively). Fatty acid uptake into brown adipose tissue (BAT) and white adipose tissue (WAT) was reduced as reflected by a decrease in the fatty acid incorporation into lipids (BAT -68%, WAT -29%. The decrease of FA incorporation was normalized by intraperitoneal administration of ASP at the time of oral fat administration. These results suggest that ASP deficiency results in energy repartitioning through different mechanisms in male and female mice.