BACKGROUND:Attenuation correction (AC) using hardware and software solutions has been shown to increase the specificity of SPECT MPI by decreasing false positive results and improving prognostic ability. Theoretically this should reduce downstream testing and unnecessary costs. We sought to assess the consequences of the use of Gd-153 scanning line source attenuation correction during SPECT myocardial perfusion imaging (MPI) on downstream invasive testing.METHODS:All patients who underwent a clinically indicated Tc-99m stress SPECT MPI study from 2013 to 2015 at five hospitals (2 with AC and 3 without) were retrospectively reviewed. Patient demographics, results of testing, subsequent coronary angiography within 3 months, and revascularization were recorded. The results of the MPI studies, downstream angiogram utilization, and results of angiography were compared and a propensity matched subgroup analysis was performed.RESULTS:A total of 9968 patients underwent SPECT MPI during the study time period (6106 performed with AC and 3862 without). Out of 3928 patients included in the propensity matched cohort, there was no difference in the proportion of abnormal MPI results between the two groups (31.5% vs 30.4%, P = 0.47), however, more patients underwent coronary angiography within 90 days in the AC group (10.6% vs 8.7%, P = 0.05). There was no significant difference in the proportion of patients with angiographically significant obstructive disease (53.4% vs 56.1%, P = 0.19), however, fewer patients in the AC group with obstructive coronary disease were revascularized (36.1% vs 46.8%, P = 0.04). The findings remained consistent after sub-group analysis in patients without known coronary disease.CONCLUSION:The use of scanning line source AC did not meaningfully influence the rate of abnormal MPI results or downstream invasive testing in this cohort. The clinical utility of scanning line source AC may be limited to facilitating stress-first imaging protocols.

Eosinophilic granulomatosis with polyangiitis (EGPA), formerly Churg-Strauss, is an anti-neutrophil cytoplasmic antibody (ANCA)-associated autoimmune vasculitis, involving small-and medium-sized arteries, which could involve several organs. This rare syndrome can present with a myriad of symptoms, which may make diagnosis challenging. It has been suggested that there are variants of EGPA, which may respond differently to available modes of treatment. Multiple and different mechanisms may be at play in each case of EGPA. This may influence the decision of clinicians to combine treatment strategies as done in this case. The addition of immunosuppressive agents other than high-dose steroids may mitigate end-organ damage, facilitate faster recovery, and prevent relapse. Rituximab among others has been seen to provide better outcomes, including a lower incidence of relapse. Mepolizumab was approved by the Food and Drug Administration (FDA) in 2017 for the treatment of EGPA. Administered at a higher dose than approved for severe eosinophilic asthma, it has been shown to lengthen remission in EGPA. The optimal dose and duration of therapy with mepolizumab remain unclear. The rarity alone of EGPA creates room for further investigation regarding pathogenesis, outcome over time, and treatment strategies, which may vary depending on how an individual case presents. This case describes the course of a 55-year-old woman who presented with respiratory symptoms, pauci-immune necrotizing granulomatous nephropathy, and neuropathy secondary to P-ANCA-positive EGPA who was successfully treated with rituximab and mepolizumab, in addition to glucocorticoids.

Background Studies suggest that patients who present with atypical chest pain and are low or low-intermediate risk can safely undergo a rapid rule-out for cardiac ischemia with serial ECGs and cardiac biomarkers followed by additional testing as needed. We sought to evaluate a novel Emergency Department (ED) protocol for patients to undergo their additional functional testing as an outpatient. Methods Patients presenting to the ED with atypical chest pain, normal ECG, and negative cardiac troponin felt to be low risk were referred for outpatient stress testing within 72 hours of presentation as part of a pilot program. We analyzed test characteristics, length of stay, and 30-day return visits to ED in the pilot group and compared results to a similar cohort assessed in the ED by a traditional chest pain observation protocol. Results A total of 156 patients were included over a 5-month period with 29.5% not returning for testing. There was a 70% reduction in length of stay for outpatient stress test protocol patients. All-cause and cardiac return visits to the ED were not significantly different between the outpatient cohort and the traditional chest pain unit group and were reduced by 47 and 75%, respectively, in patients who completed their outpatient testing. The provisional injection protocol resulted in a 81% reduction in radiation exposure when compared to traditional MPI stress protocols due to a greater utilization of exercise treadmill tests without imaging. Conclusion Outpatient stress testing is a reliable alternative to traditional chest pain observation with a significantly shorter length of stay, reduced healthcare costs, and improved radiation safety profile for patients when compared to traditional inpatient observation.