Postural orthostatic tachycardia syndrome after COVID-19 vaccination

BACKGROUND

There is an association between coronavirus disease 2019 (COVID-19) mRNA vaccination and the incidence or exacerbation of postural orthostatic tachycardia syndrome (POTS).

OBJECTIVE

The purpose of this study was to characterize patients reporting new or exacerbated POTS after receiving the mRNA COVID-19 vaccine.

METHODS

We prospectively collected data from sequential patients in a POTS clinic between July 2021 and June 2022 reporting new or exacerbated POTS symptoms after COVID-19 vaccination. Heart rate variability (HRV) and skin sympathetic nerve activity (SKNA) were compared against those of 24 healthy controls.

RESULTS

Ten patients (6 women and 4 men; age 41.5 ± 7.9 years) met inclusion criteria. Four patients had standing norepinephrine levels > 600 pg/mL. All patients had conditions that could raise POTS risk, including previous COVID-19 infection (N = 4), hypermobile Ehlers-Danlos syndrome (N = 6), mast cell activation syndrome (N = 6), and autoimmune (N = 7), cardiac (N = 7), neurological (N = 6), or gastrointestinal conditions (N = 4). HRV analysis indicated a lower ambulatory root mean square of successive differences (46.19 ±24 ms; P = .042) vs control (72.49 ± 40.8 ms). SKNA showed a reduced mean amplitude (0.97 ± 0.052 μV; P = .011) vs control (1.2 ± 0.31 μV) and burst amplitude (1.67 ± 0.16 μV; P = .018) vs control (4. 3 ± 4.3 μV). After 417.2 ± 131.4 days of follow-up, all patients reported improvement with the usual POTS care, although 2 with COVID-19 reinfection and 1 with small fiber neuropathy did have relapses of POTS symptoms.

CONCLUSION

All patients with postvaccination POTS had pre-existing conditions. There was no evidence of myocardial injuries or echocardiographic abnormalities. The decreased HRV suggests a sympathetic dominant state. Although all patients improved with guideline-directed care, there is a risk of relapse.

Skin sympathetic nerve activity and nocturnal blood pressure nondipping in patients with postural orthostatic tachycardia syndrome

OBJECTIVE

Postural orthostatic tachycardia syndrome (POTS) is associated with abnormal blood pressure (BP) regulation and increased prevalence of nocturnal nondipping. We hypothesized that nocturnal nondipping of BP is associated with elevated skin sympathetic nerve activity (SKNA) in POTS.

METHOD

We used an ambulatory monitor to record SKNA and electrocardiogram from 79 participants with POTS (36 ± 11 years, 72 women), including 67 with simultaneous 24-h ambulatory BP monitoring.

RESULTS

Nocturnal nondipping of BP was present in 19 of 67 (28%) participants. The nondipping group had a higher average SKNA (aSKNA) from midnight of day 1 to 0100 h on day 2 than the dipping group ( P  = 0.016, P  = 0.030, respectively). The differences (Δ) of aSKNA and mean BP between daytime and night-time were more significant in the dipping group compared with the nondipping group (ΔaSKNA 0.160 ± 0.103 vs. 0.095 ± 0.099 μV, P  = 0.021, and Δmean BP 15.0 ± 5.2 vs. 4.9 ± 4.2 mmHg, P  < 0.001, respectively). There were positive correlations between ΔaSKNA and standing norepinephrine (NE) (r = 0.421, P  = 0.013) and the differences between standing and supine NE levels ( r  = 0.411, P  = 0.016). There were 53 (79%) patients with SBP less than 90 mmHg and 61 patients (91%) with DBP less than 60 mmHg. These hypotensive episodes were associated with aSKNA of 0.936 ± 0.081 and 0.936 ± 0.080 μV, respectively, which were both significantly lower than the nonhypotensive aSKNA (1.034 ± 0.087 μV, P  < 0.001 for both) in the same patient.

CONCLUSION

POTS patients with nocturnal nondipping have elevated nocturnal sympathetic tone and blunted reduction of SKNA between day and night. Hypotensive episodes were associated with reduced aSKNA.

Noninvasive Fibrosis Screening in Fatty Liver Disease Among Vulnerable Populations: Impact of Diabetes and Obesity on FIB-4 Score Accuracy

OBJECTIVE

Fatty liver disease (FLD) is prevalent in diabetes, and both disproportionately affect vulnerable populations. The FIB-4 index is recommended to screen for advanced liver fibrosis. Limited data have suggested that diabetes may impact FIB-4.

RESEARCH DESIGN AND METHODS

We evaluated FIB-4 accuracy for advanced fibrosis compared with liver biopsy in the presence of diabetes and obesity.

RESULTS

Among 363 FLD patients receiving care in San Francisco's safety net health care system from August 2009 to February 2020, characteristics were as follows: median age 51 years, 46% male, 59% Hispanic, 68% obese, 33% with diabetes, and 31% with advanced fibrosis on histology. Overall, the c-statistic for FIB-4 was 0.79, but was worse in patients with diabetes, 0.68, than without, 0.85 (P = 0.003). Accuracy also varied by weight, at 0.65, 0.85, and 0.75 for normal weight, overweight, and obese, respectively, although not significantly (P = 0.24).

CONCLUSIONS

The findings highlight limitations of FIB-4 in screening for advanced liver fibrosis, particularly in individuals with diabetes.

Racial/ethnic differences in fibrosis prevalence and progression in biopsy-proven steatosis: A focus on the Asian American population

Fatty liver disease (FLD) is a leading cause of chronic liver disease (CLD) globally, and vulnerable populations are disproportionately affected. Prior studies have suggested racial/ethnic differences in FLD prevalence and severity; however, these studies often excluded Asian Americans. This study aims to evaluate racial/ethnic differences in the prevalence of, and predictors associated with steatohepatitis, advanced fibrosis, and fibrosis progression over time within a diverse population. Using descriptive analyses and multivariable modeling, we performed a longitudinal evaluation of 648 patients with histologic evidence of FLD (steatosis or steatohepatitis) from August 2009 to February 2020 within San Francisco's safety-net health care system. Overall demographics were median age of 53 years, 54% male, and 38% Asian (40% Hispanic, 14% White). On histology, 61% had steatohepatitis and 30% had advanced fibrosis (≥F3). The comparison between steatosis and steatohepatitis groups showed differences in sex, race/ethnicity, metabolic risk factors, and co-existing CLD (predominantly viral hepatitis); patients with steatosis were more likely to be Asian (50%), and those with steatohepatitis were more likely to be Hispanic (51%). On multivariable modeling, while Asian race (vs. non-Asian) was not associated with steatohepatitis or advanced fibrosis when models included all relevant clinical predictors, Asian race was associated with higher relative risk of fibrosis progression as defined by change in Fibrosis-4 category over time (relative risk ratio = 1.9; p = 0.047). Conclusion: In this vulnerable population with a large proportion of Asian Americans, Asian race was associated with progression of fibrosis. Given the relative paucity of data in this high-risk group, future studies should confirm these findings.

Abstract P235: Relationship Between Skin Sympathetic Nerve Activity And Nocturnal Non-dipping Blood Pressure In Patients With Postural Orthostatic Tachycardia Syndrome

Background: Patients with postural orthostatic tachycardia syndrome (POTS) have a high incidence of nocturnal non-dipping of blood pressure (BP).

Objective: To test the hypothesis that non-dipping of BP is associated with persistently elevated nocturnal skin sympathetic nerve activity (SKNA) in patients with POTS.

Methods: We used Bittium Faros 180 ECG monitor to simultaneously record electrocardiogram (ECG) and SKNA, and SpaceLab OnTrak arterial BP monitor (ABPM) over 24-hr in 55 POTS patients (51 women, 36±10 years-old). The Faros signals were high pass filtered at 300 Hz to display the SKNA. The same original signals were bandpass filtered 0.05-150 Hz to display ECG. BP was measured every 30-min when awake (7 AM to 9 PM) and hourly at night (9 PM to 7 AM).

Results: The overall successful ABPM measurement was 71±18%. Nocturnal dipping of BP was presented in 40 patients with an average dipping% of 15.5±4.8%. Nocturnal non-dipping of BP was present in 15 patients with an average dipping% of 3.9±3.7% (p<0.001). Figure A shows hourly averaged SKNA. A mixed effect model was used to compare the log (SKNA) values of two groups of patients at all time points, with patient as a random effect. The non-dipping group had higher SKNA from midnight of day 1 to 4 am of day 2 (indicated by the red bars, p=0.0118, 0.0223, 0.0402, 0.0382, 0.0424). The difference between awake time and sleep time (determined by patients’ diary) average SKNA was 0.155±0.106 μV in dipping group and 0.076± 0.101 μV in the non-dipping group (p=0.017, Figure B ).

Conclusion: Nocturnal non-dipping of BP is associated with non-dipping of SKNA in patients with POTS suggesting sympathetic nerve activity plays an important mechanistic role.

Multiple lineages of Streptomyces produce antimicrobials within passalid beetle galleries across eastern North America

Some insects form symbioses in which actinomycetes provide defense against pathogens by making antimicrobials. The range of chemical strategies employed across these associations, and how these strategies relate to insect lifestyle, remains underexplored. We assessed subsocial passalid beetles of the species Odontotaenius disjunctus, and their frass (fecal material), which is an important food resource within their galleries, as a model insect/actinomycete system. Through chemical and phylogenetic analyses, we found that O. disjunctus frass collected across eastern North America harbored multiple lineages of Streptomyces and diverse antimicrobials. Metabolites detected in frass displayed synergistic and antagonistic inhibition of a fungal entomopathogen, Metarhizium anisopliae, and multiple streptomycete isolates inhibited this pathogen when co-cultivated directly in frass. These findings support a model in which the lifestyle of O. disjunctus accommodates multiple Streptomyces lineages in their frass, resulting in a rich repertoire of antimicrobials that likely insulates their galleries against pathogenic invasion.