Subclinical elevated B-type Natriuretic Peptide (BNP) indicates endothelial dysfunction contributing to hypoxia susceptibility in healthy individuals

Hypoxic pulmonary vascular response can screen subclinical lifestyle disease in healthy population

OBJECTIVE

Subclinical life style disease can cause endothelial dysfunction associated with perfusion abnormalities and reduced vascular compliance. Subclinical elevated beta type natriuretic peptide (BNP) has been associated with altered fluid shift from extra to intracellular space during acute hypoxia. Therefore we measured vascular response and BNP levels during acute hypoxia to study endothelial functions among healthy individuals.

METHODS

Individuals were exposed to acute normobaric hypoxia of FiO2 = 0.15 for one hour in supine position and their pulmonary and systemic vascular response to hypoxia was compared. Individuals were divided into two groups based on either no response (Group 1) or rise in systolic pulmonary artery pressure to hypoxia (Group 2) and their BNP levels were compared.

RESULTS

BNP was raised after hypoxia exposure in group 2 only from 18.52 ± 7 to 21.56 ± 10.82 picogram/ml, p < 0.05. Group 2 also showed an increase in mean arterial pressure and no fall in total body water in response to acute hypoxia indicating decreased endothelial function compared to Group 1.

CONCLUSION

Rise in pulmonary artery pressure and BNP level in response to acute normobaric hypoxia indicates reduced endothelial function and can be used to screen subclinical lifestyle disease among healthy population.

Implications of microvascular dysfunction and nitric oxide mediated inflammation in severe COVID-19 infection

Infection with COVID-19 has resulted in over 276,000 deaths in the United States and over 1.5 million deaths globally, with upwards of 15% of patients requiring hospitalization. Severe COVID-19 infection is, in essence, a microvascular disease. This contention has been emphasized throughout the course of the pandemic, particularly due to the clinical manifestation of severe infection. In fact, it has been hypothesized and shown in particular instances that microvascular function is a significant prognosticator for morbidity and mortality. Initially thought to be isolated to the pulmonary system and resulting in ARDS, patients with COVID-19 have been observed to have acute cardiac, renal, and thrombolytic complications. Therefore, severe COVID-19 is a vascular disease that has systemic implications. The objective of this review is to provide a mechanistic background for the microvascular nature of severe COVID-19 infection, with a particular emphasis on dysfunction of the endothelial glycocalyx and nitric oxide mediated pathogenesis.

Post-exercise accumulation of interstitial lung water is greater in hypobaric than normobaric hypoxia in adults born prematurely

We aimed to gauge the interstitial lung water accumulation following moderate-intensity exercise under normobaric and hypobaric hypoxic conditions in a group of preterm born but otherwise healthy young adults. Sixteen pre-term-born individuals (age = 21±2yrs.; gestational age = 29±3wk.; birth weight = 1160±273 g) underwent two 8 -h hypoxic/altitude exposures in a cross-over manner: 1) Normobaric hypoxic exposure (NH; F_IO₂ = 0.142±0.001; P_IO₂  = 90.6±0.9 mmHg) 2) Hypobaric hypoxic exposure (HH; terrestrial high-altitude 3840 m; P_IO₂  = 90.2±0.5 mmHg). Interstitial lung water was assessed via quantification of B-Lines (using lung ultrasound) before (normoxia) and after 4-h and 8-h of respective exposures. At each time point, B-Lines were quantified before (Pre) and immediately after (Post) a 6-min moderate-intensity exercise. The baseline B-lines count were comparable between both conditions (P = 0.191). A higher B-lines count was noted at Pre-H4 in HH versus NH (P = 0.0420). At Post-H8 B-lines score was significantly higher in HH (4.6 ± 1.6) than in NH (3.1 ± 1.4; P = 0.0073). Furthermore, at this time point, a significantly higher number of individuals with B-line scores ≥5 was observed in HH (n = 7) than in NH (n = 3; P = 0.0420). These findings suggest that short moderate-intensity exercise provokes a significant increase in the interstitial lung water accumulation after 8 h of exposure to terrestrial but not simulated altitude (≈3840 m) in prematurely born adults. Further work is needed to elucidate the exact mechanisms of (moderate-intensity) exercise-induced interstitial lung water accumulation in this population and directly compare the obtained data to full-term born adults.

Natriuretic Peptide Levels and Clinical Outcomes Among Patients Hospitalized With Coronavirus Disease 2019 Infection

OBJECTIVES

There is increasing evidence of cardiovascular morbidity associated with severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019). Pro-B-type natriuretic peptide is a biomarker of myocardial stress, associated with various respiratory and cardiac outcomes. We hypothesized that pro-B-type natriuretic peptide level would be associated with mortality and clinical outcomes in hospitalized coronavirus disease 2019 patients.

DESIGN

We performed a retrospective analysis using adjusted logistic and linear regression to assess the association of admission pro-B-type natriuretic peptide (analyzed by both cutoff > 125 pg/mL and log transformed pro-B-type natriuretic peptide) with clinical outcomes. We additionally treated body mass index, a confounder of both pro-B-type natriuretic peptide levels and coronavirus disease 2019 outcomes, as an ordinal variable.

SETTING

We reviewed hospitalized patients with coronavirus disease 2019 who had a pro-B-type natriuretic peptide level measured within 48 hours of admission between March 1, and August 31, 2020, from a multihospital U.S. health system.

PATIENTS

Adult patients (≥ 18 yr old; n = 1232) with confirmed coronavirus disease 2019 admitted to the health system.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

After adjustment for demographics, comorbidities, and troponin I level, higher pro-B-type natriuretic peptide level was significantly associated with death and secondary outcomes of new heart failure, length of stay, ICU duration, and need for ventilation among hospitalized coronavirus disease 2019 patients. This significance persisted after adjustment for body mass index as an ordinal variable. The adjusted hazard ratio of death for log transformed pro-B-type natriuretic peptide was 1.56 (95% CI, 1.23-1.97; p < 0.0001).

CONCLUSIONS

Further investigation is warranted on the utility of pro-B-type natriuretic peptide for clinical prognostication in coronavirus disease 2019 as well as implications of abnormal pro-B-type natriuretic peptide in the underlying pathophysiology of coronavirus disease 2019-related myocardial injury.