Condition-specific Streaming versus an Acuity-based Model of Cardiovascular Care: A Historically-controlled Quality Improvement Study Evaluating the Association with Early Clinical Events.

BACKGROUND: Ensuring optimal evidence translation is challenging when health-service design has not kept pace with developments in care. Differences in patient outcomes were evident when specific cardiac conditions were discordant with the subspecialty of the cardiologists managing their care. We prospectively explored the clinical and health service implications of a "condition-based" redesign in cardiac care delivery, rather than acuity-based, within a tertiary hospital. METHODS: Prospective evaluation of a disease-specific streaming model of care compared to propensity-matched historical controls, among cardiac patients admitted to a tertiary hospital cardiology unit was undertaken. The outcome measures of 30-day death, and readmission for myocardial infarction, cardiac arrhythmia, and heart failure were explored. RESULTS: In total, 2018 patients admitted subsequent to the implementation of the streaming model were compared with 1830 patients admitted prior. The median age was 68.9 years, and 39.5% were female. There was no significant difference in the overall proportion of patients admitted with an acute coronary syndrome, arrthythmia or heart failure, nor their Charlson index before and after streaming. Subsequent to the implementation, there was a reduction in the use of angiography (pre: 35.4% vs. post: 31.2%, p=0.007) and echocardiography (pre: 59.4% vs. post: 55.6%, p=0.007). A reduction in length of length-of-stay was observed in the entire cohort (pre: 2.7 (range: 1.2-5.0) days vs. post: 2.3 (range 1.0-4.5) days, p=0.0003). By 30 days, the propensity-adjusted hazard ratio for major adverse cardiac events and death or any cardiovascular admission was 0.76 (95% C.I. 0.59-0.97, p=0.026). CONCLUSION: Cardiac service redesign that streams cardiac patients by presenting diagnosis into teams designed to treat that condition may provide capacity and productivity gains for health services striving to improve outcome and efficiency.

Gender differences in the relationship between leptin, insulin resistance and the autonomic nervous system.

OBJECTIVES: Leptin, an important hormonal regulator of body weight, has been shown to stimulate the sympathetic nervous system (SNS) in vitro although the physiological relevance remains unclear. Increased SNS activity has been implicated in the pathogenesis of insulin resistance and an increased cardiovascular risk. We have therefore investigated the relationship between leptin, insulin resistance and cardiac autonomic activity in healthy young adults. 130 healthy men and women age 20.9 years were studied. Insulin sensitivity was assessed using the IVGTT and minimal model with simultaneous measures of leptin. Cardiac autonomic activity was assessed using spectral analysis of heart rate variability. RESULTS: Women showed significantly higher fasting leptin, heart rate and cardiac sympathetic activity, and lower insulin sensitivity. Men showed inverse correlations between insulin resistance and heart rate, and between insulin resistance and cardiac sympatho-vagal ratio. Women, in contrast, showed no SNS relationship with insulin resistance, but rather an inverse correlation between leptin and the sympatho-vagal ratio, suggesting that leptin in women is associated with SNS activity. The correlation remained significant after adjustment for BMI and waist-to-hip ratio (beta=-0.33 and p=0.008). CONCLUSION: Insulin resistance and SNS activity appear to be linked, although the relationship showed marked gender differences, and the direction of causality was unclear from this cross-sectional study. Leptin appears to exert a greater effect on the SNS in women, possibly because of their greater fat mass.