Impact of Pulmonary Hypertension Hemodynamic Phenotype on Incident Atrial Fibrillation

INTRODUCTION

Atrial fibrillation/flutter (AF) is common among patients with pulmonary hypertension (PH) and is associated with poor clinical outcomes. AF has been shown to occur more commonly among patients with postcapillary PH, although AF also occurs among patients with precapillary PH. The goal of this study was to evaluate the independent impact of PH hemodynamic phenotype on incident AF among patients with PH.

METHODS

We retrospectively identified 262 consecutive patients, without a prior diagnosis of atrial arrhythmias, seen at the PH clinic at Mayo Clinic, Florida, between 1997 and 2017, who had right heart catheterization and echocardiography performed, with follow-up for outcomes through 2021. Kaplan-Meier analysis and Cox-proportional hazards regression modeling were used to evaluate the independent effect of PH hemodynamic phenotype on incident AF.

RESULTS

Our study population was classified into two broad PH hemodynamic groups: precapillary (64.9%) and postcapillary (35.1%). The median age was 59.5 years (Q1: 48.4, Q3: 68.4), and 72% were female. In crude models, postcapillary PH was significantly associated with incident AF (HR 2.17, 95% CI: 1.26-3.74, p = 0.005). This association was lost following multivariable adjustment, whereas left atrial volume index remained independently associated with incident AF (aHR 1.30, 95% CI: 1.09-1.54, p = 0.003).

CONCLUSION

We found PH hemodynamic phenotype was not significantly associated with incident AF in our patient sample; however, echocardiographic evidence of left atrial remodeling appeared to have a greater impact on AF development. Larger studies are needed to validate these findings and identify potential modifiable risk factors for AF in this population.

Cardiovascular Concerns from COVID-19 in Pilots

BACKGROUND: Cardiovascular disease, now complicated by the COVID-19 pandemic, remains a leading cause of death and risk for sudden incapacitation for pilots during flight. The capacity for aeromedically significant cardiovascular sequelae with potentially imperceptible clinical symptoms elicits concern both during and following resolution of acute COVID-19 in pilots.OBJECTIVE: We summarize the current state of knowledge regarding COVID-19 cardiovascular implications as applied to the aviation environment to better understand their significance toward flight safety and application toward a focused cardiovascular screening protocol following recovery from infection.METHODS: A narrative review of the cardiovascular implications of COVID-19 infection was performed using the PubMed literature search engine and existing organizational guidelines. In addition, to established medical aviation benchmarks, surrogate populations examined included high performance athletes (as a correlate for high G-forces), and scuba divers (as an environmental work analog). Conditions of primary concern included myocardial injury, proarrhythmic substrates, risk of sudden death, myopericarditis, pulse orthostatic lability in response to vigorous activity, cardiovagal dysfunction, and thromboembolic disease.LITERATURE REVIEW: Cardiovascular screening guideline recommendations post-infection recovery are suggested based on profile stratification: airperson flight class, tactical military, and aerobatic pilots. This provides an approach to inform aeromedical decision making.CONCLUSION: Aviation medical examiners should remain cognizant of the clinically apparent and occult manifestations of cardiovascular dysfunction associated with COVID-19 infection when applying return-to-work screening guidelines. This will ensure high flight safety standards are maintained and sudden incapacitation risk mitigated during and following the ongoing pandemic.Elkhatib W, Herrigel D, Harrison M, Flipse T, Speicher L. Cardiovascular concerns from COVID-19 in pilots. Aerosp Med Hum Perform. 2022; 93(12):855-865.

Overwhelming cryptococcosis complicated by cryptococcal endocarditis

Cryptococcal species endocarditis is infrequently described, carries high mortality and nearly always occurs in immunocompromised states or on prosthetic valves. We report the case of a man in his 70s with multiple recent hospitalisations for pneumonia, hypercalcaemia and septic tank exposure who presented with intermittent fevers, progressive weakness,and worsening encephalopathy, manifested as confusion and word-finding difficulties for 3 weeks. Workup revealed cryptococcal species on blood serum gram stain, native aortic valve endocarditis and meningitis. Cerebrospinal fluid analysis demonstrated lymphocytosis, ultimately found to be secondary to chronic lymphocytic leukaemia. Surgical valve replacement was deemed medically contraindicated and antifungal therapy was initiated. Though poorly understood with very few documented cases, management of cryptococcal endocarditis relies on prompt diagnosis, early surgery when indicated, long-term antifungal therapy and treatment of underlying immunocompromising states where possible.

Effects of treadmill running in a rat model of chronic kidney disease

Chronic kidney disease (CKD) progression results in musculoskeletal dysfunction that is associated with a higher likelihood of hospitalization and is predictive of hospitalizations and mortality. Despite this, there is a lack of effective interventions to treat the musculoskeletal dysfunction. We studied treadmill running as an intervention to improve musculoskeletal health in a translational rat model that has slowly progressive CKD. CKD rats were subjected to treadmill exercise or no treadmill exercise for 10 weeks (n = 8 each group). Animals ran for 60 min, 5 times per week starting at a speed of 8 m/min and ending at 18 m/min (1 m/min increase/week). Treadmill training had no effect on muscle strength (assessed as maximally stimulated torque), half-relaxation time (time from peak torque to 50%) or muscle cross-sectional area. Overall, there were no biochemical improvements related to CKD progression. Skeletal muscle catabolism was higher than non-exercised animals without a concomitant change in muscle synthesis markers or regeneration transcription factors. These results suggest that aerobic exercise, achieved via treadmill running was not protective in CKD animals and actually produced potentially harmful effects (increased catabolism). Given the high prevalence and dramatic musculoskeletal mobility impairment in patients with CKD, there is a clear need to understand how to effectively prescribe exercise in order to benefit the musculoskeletal system.

Novel Approach Against Central Venous Catheter Associated Infection With Acinetobacter Baumannii Biofilm

Central venous catheter (CVC)-associated infections have substantial impacts on morbidity, mortality, and overall cost of health care. Acinetobacter baumannii causes severe infections, survives on abiotic surfaces, colonizes and develops resistant biofilm on different medical devices including CVC. The cranberry contains proanthocyanidines which possess antiadherent activity against colonic bacteria. This study aimed to assess the use of moxifloxacin/cranberry extract combination against A. baumannii biofilm established on CVC. A. baumannii bioflim was developed on silicone CVC and visualized by electron microscopy. The biofilm was treated according to the method described by Aslam et al. Briefly, segments (1 cm) of silicone CVC (Cook, Inc., Bloomington, IN) were incubated in bacterial suspensions (106 CFU/ml) in Mueller Hinton broth to allow biofilm formation. After incubation at 37°C for 24 h, segments were aseptically removed. Four sets of catheter segments (3 segments/each) were suspended for 6 h at 37°C in one of the following solutions: moxifloxacin (0.16 ug/mL), cranberry aqueous extract (10 mg/mL), Mox-Cran combination, or normal saline (NS) as a control. Catheter segments were rinsed 3 times with NS to remove planktonic bacteria. These segments were individually sonicated for 5 min and vortexed for 30s in 1 ml NS. Aliquots (100 uL) of the sonicated fluids and their dilutions were inoculated onto Mueller Hinton agar plates. Each set of experiments was repeated three times. Bacterial colonies (CFU/cm) were counted after incubation for 24 h. The average colony count of each set of experiment was calculated. The average values of the treated sets were divided by the average value of the control percent for calculation of the percentage biofilm reduction in each treatment as compared to the untreated control (NS). Using ANOVA, the significance level for all analyses was <0.05. The effect of moxifloxacin alone was similar to the untreated control. Cranberry extract could reduce the biofilm by almost 90%. Moreover, MoxDran combination could synergistically and completely (100%) eradicate. A. Baumannii biofilm from CVC. There is a dire need for developing novel strategies against microbial biofilms on medical devices, such as the use of combination between safe anti-adherent extracts with antimicrobial agent as a catheter lock solution, to retrieve the infected vascular catheters. The results of this study revealed a promising antibiofilm activity of moxifloxacin/cranberry extract combination for eradication of mature A. baumannii biofilm from CVC (therapeutic approach). Since biofilm prevention is much easier than its eradication, we hypothesize that impregnation or coating of medical devices, including CVC, with such novel and safe combination might be an outstanding tool against biofilm development (prophylactic approach).