Trends in the use of echocardiography and left ventriculography to assess left ventricular ejection fraction in patients hospitalized with acute myocardial infarction

Remote ischemic preconditioning and hypoxia-induced biomarkers in acute myocardial infarction: study on a porcine model

Objectives. Remote ischemic preconditioning (RIPC) mitigates acute myocardial infarction (AMI). We hypothesized that RIPC reduces the size and severity of AMI and explored molecular mechanisms behind this phenomenon. Design. In two series of experiments, piglets underwent 60 min of the circumflex coronary artery occlusion, resulting in AMI. Piglets were randomly assigned into the RIPC groups (n = 7 + 7) and the control groups (n = 7 + 7). The RIPC groups underwent four 5-min hind limb ischemia-reperfusion cycles before AMI. In series I, the protective efficacy of RIPC was investigated by using biomarkers and echocardiography with a follow-up of 24 h. In series II, the heart of each piglet was harvested for TTC-staining to measure infarct size. Muscle biopsies were collected from the hind limb to explore molecular mechanisms of RIPC using qPCR and Western blot analysis. Results. The levels of CK-MBm (p = 0.032) and TnI (p = 0.007) were lower in the RIPC group. Left ventricular ejection fraction in the RIPC group was greater at the end of the follow-up. The myocardial infarct size in the RIPC group was smaller (p = 0.033). Western blot indicated HIF1α stabilization in the skeletal muscle of the RIPC group. PCR analyses showed upregulation of the HIF target mRNAs for glucose transporter (GLUT1), glucose transporter 4 (GLUT4), phosphofructokinase 1 (PFK1), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), enolase 1 (ENO1), lactate dehydrogenase (LDHA) and endothelial nitric oxidate synthase (eNOS). Conclusions. Biochemical, physiologic, and histologic evidence confirms that RIPC decreases the size of AMI. The HIF pathway is likely involved in the mechanism of the RIPC.

Reducing Unnecessary Noninvasive Testing for Inpatients With Unstable Angina: The RUNIT Protocol

Background

Routine inpatient transthoracic echocardiography (TTE) for patients with unstable angina is common, but it anecdotally adds little value to clinical care. A practice audit at our academic hospital demonstrated that 61.5% of patients with troponin-negative chest pain (TNCP) had normal left ventriculography (LVG) during coronary angiography and normal TTE on the same admission (duplicate testing).

Methods

We developed the Reducing Non-Invasive Testing (RUNIT) protocol, a clinical algorithm applied by clinical nurses to patient with TNCP. We performed a prospective assessment of rate of duplicate testing before and after intervention. If patients met certain simple clinical criteria, their TTE was cancelled (RUNIT positive). Patients then proceeded to have either coronary angiography with LVG or noninvasive risk stratification. We aimed to reduce duplicate testing by 25% over a 1-year period. Balancing measures included pathology on ordered TTEs, 30-day readmission, length of stay, and number of LVG.

Results

Among 254 patients admitted with TNCP over 12 months, we reduced duplicate testing from 61.5% (before intervention) to 34% (P = 0.001). There was no clinical difference in 30-day readmission (0.9% vs 0.7%), and length of stay was significantly shorter in RUNIT positive (3.48 vs 4.16 days, P = 0.02). The majority of duplicate TTEs did not reveal any management-informing pathology. RUNIT-positive patients underwent more LVG than RUNIT-negative patients (78.3% vs 62.8%, P = 0.008).

Conclusion

We achieved a sustained reduction in reflexive TTE ordering in patients with TNCP, and we discuss the potential of nursing-led interventions to address other areas of low value care in cardiology.

Left Ventricular Ejection Fraction Assessment Among Patients With Acute Myocardial Infarction and Its Association With Hospital Quality of Care and Evidence-Based Therapy Use

Background—

The left ventricular ejection fraction (LVEF) has prognostic and therapeutic utility after acute myocardial infarction (AMI). Although LVEF assessment is a key performance measure among AMI patients, contemporary rates of in-hospital assessment and its association with therapy use have not been well characterized.

Methods and Results—

We examined rates of in-hospital LVEF assessment among 77 982 non–ST-elevation myocardial infarction patients and 50 863 ST-elevation myocardial infarction patients in Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With The Guidelines between January 2007 and September 2009, after excluding patients who died in-hospital or who were transferred to another acute care facility, discharged to end-of-life care, or had missing LVEF assessment status. LVEF assessment increased significantly over time, with higher rates among ST-elevation myocardial infarction than non–ST-elevation myocardial infarction patients (95.1% versus 91.6%; P <0.001). Excluding patients with prior heart failure did not alter these observations. Significant interhospital variability in LVEF assessment rates was observed. Compared with patients with in-hospital LVEF assessment, patients who did not have LVEF assessed were older and more likely to have clinical comorbidities. In multivariable modeling, lower overall hospital quality of AMI care was also associated with lower likelihood of LVEF assessment (odds ratio for failure to assess LVEF, 1.09; 95% confidence interval, 1.05–1.13 per 10% decrease in defect-free care). Patients with in-hospital LVEF assessment were more likely to be discharged on evidence-based secondary prevention medication therapies compared with paients without LVEF assessment.

Conclusions—

The assessment of LVEF among patients with AMI has improved significantly over time, yet significant interhospital variability exists. Patients who did not have in-hospital LVEF assessment were less likely to receive evidence-based medications at discharge. These patients represent targets for future quality improvement efforts.