Seroprevalence of Novel Coronavirus SARS-CoV-2 at a Community Hospital Emergency Department and Outpatient Laboratory in Northern Orange County, California.

INTRODUCTION: The severe acute respiratory syndrome related coronavirus 2 (SARS-CoV-2) has infected more than 20 million people worldwide, and the spread is most prevalent in the USA, where California had accounted over 240,000 cases in the initial 5 months of the pandemic. To estimate the number of infected persons in our community, we conducted a cross-sectional study to estimate seroprevalence of SARS-CoV-2 infection. METHODS: This cross-sectional study evaluated the presence of immunoglobulin G, antibody for SARS-CoV-2 during the time period of July 15, 2020, to July 27, 2020. Testing was done on serum samples from patients who had visited affiliated outpatient clinics or our emergency department. Additionally, we collected age, gender, ethnicity, race, and location of testing. RESULTS: Eight hundred sixty-five tests were included in the study. The outpatient clinics cohort accounted for 56% of results and emergency department (ED) contributed 44%. The positive percentage of SARS-CoV-2 test was 9.4% (95% CI: 0.08-0.12). The positivity rates of the outpatient (5.6%) and ED (14.2%) setting differed. The prevalence of SARS-CoV-2 IgG was greatest in those that identified as Hispanic/Latino, 18.1% versus 13.4% in other groups. Specifically compared to the non-Hispanic/Latino population, the prevalence was significantly higher, with a relative risk of 2.73 (95% CI: 1.8-4.1), p < 0.0001. CONCLUSION: The low antibody positivity rate in the community indicates the need for a vaccine. The Hispanic/Latino patient population should be considered for increased education on preventing transmission and acquisition of COVID-19 as well as being considered as a priority for vaccination once a vaccine is available.

Changes in abdominal aortic diameter in response to the cold pressor test and nitroglycerin: a new noninvasive model for the assessment of endothelial-dependent and endothelial-independent vascular relaxation.

Coronary vascular responses to the cold pressor test (CPT) have been shown to parallel changes caused by infusion of acetylcholine. Whereas the CPT is a method of assessing endothelial-dependent vasodilation, nitroglycerin produces endothelial-independent vasodilation. We performed histological studies on autopsy specimens of abdominal aorta and demonstrated that it is predominantly muscular artery. To test the hypothesis that vasodilatory responses of the abdominal aorta to interventions would parallel those of peripheral vessels, 33 normal males without hypertension, diabetes, or hyperlipidemia, and 10 younger male smokers had ultrasound imaging of the abdominal aorta conducted in the control state, 2 minutes after immersion of the hand in cold water and 10 minutes after rewarming the hand (i.e., cold pressor test). The internal diameter of the abdominal aorta at the onset of the QRS complex was determined for each intervention by averaging 4 beats. It was found that the cold pressor test and nitroglycerin resulted in similar degrees of dilation of the abdominal aorta in nonsmoking subjects, and that these responses were attenuated in smokers. Thus, both endothelial-dependent and endothelial-independent vascular relaxation were impaired in smokers.

Severity of Aortic Regurgitation Assessed by Digital Image Processing of Doppler Spectral Recordings.

Visual estimates of the intensity of the regurgitant signal (RS) obtained by continuous-wave (CW) Doppler has been used as an indicator of the severity of aortic regurgitation (AR). This study was designed to test this concept quantitatively using digital image processing methods. Twenty-one patients with AR were studied, 14 of whom had concomitant mitral valve disease. Patients with aortic stenosis were excluded. By angiography, 10 patients had mild (grade 1 or 2), 5 had moderate (grade 3), and 6 severe (grade 4) AR. We digitized three well-defined AR envelopes and calculated the mean pixel intensity (MPI) of the RS and the systolic flow signal (SFS) using an offline computer analysis system developed in our laboratory. To negate the effects of different gain settings, the ratio of RS to SFS (RS/SFS ratio) was compared to angiographic grade of AR. Thus, each patient served as his own control. The mean RS/SFS ratio was 0.54 +/- 0.42 SD (range 0.46-0.59) for mild AR, 0.76 +/- 0.71 SD (range 0.65-0.82) for moderate AR, and 0.84 +/- 0.52 (range 0.77-0.92) for severe AR. This RS/SFS ratio correlated well with angiographic severity of AR (r = 0.9). A ratio of <0.6 identified patients with mild AR and >0.6 correlated with moderate-to-severe AR. We conclude that the ratio of the regurgitant to systolic flow CW Doppler signal is an accurate noninvasive indicator of AR severity. (ECHOCARDIOGRAPHY, Volume 13, May 1996)