scholarly journals High-altitude Pulmonary Hypertension: an Update on Disease Pathogenesis and Management

2016 ◽  
Vol 10 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Aibek E. Mirrakhimov ◽  
Kingman P. Strohl
Keyword(s):  
Pulmonary Hypertension ◽  
High Altitude ◽  
Indoor Air Pollution ◽  
Screening Tools ◽  
Heart Catheterization ◽  
Low Oxygen ◽  
Lower Altitude ◽  
Individualized Approach ◽  
Chest X Ray ◽  
Low Oxygen Concentration

High-altitude pulmonary hypertension (HAPH) affects individuals residing at altitudes of 2,500 meters and higher. Numerous pathogenic variables play a role in disease inception and progression and include low oxygen concentration in inspired air, vasculopathy, and metabolic abnormalities. Since HAPH affects only some people living at high altitude genetic factors play a significant role in its pathogenesis. The clinical presentation of HAPH is nonspecific and includes fatigue, shortness of breath, cognitive deficits, cough, and in advanced cases hepatosplenomegaly and overt right-sided heart failure. A thorough history is important and should include a search for additional risk factors for lung disease and pulmonary hypertension (PH) such as smoking, indoor air pollution, left-sided cardiac disease and sleep disordered breathing. Twelve-lead electrocardiogram, chest X-ray and echocardiography can be used as screening tools. A definitive diagnosis should be made with right-sided heart catheterization using a modified mean pulmonary artery pressure of at least 30 mm Hg, differing from the 25 mm Hg used for other types of PH. Treatment of HAPH includes descent to a lower altitude whenever possible, oxygen therapy and the use of medications such as endothelin receptor antagonists, phosphodiesterase 5 blockers, fasudil and acetazolamide. Some recent evidence suggests that iron supplementation may also be beneficial. However, it is important to note that the scientific literature lacks long-term randomized controlled data on the pharmacologic treatment of HAPH. Thus, an individualized approach to treatment and informing the patients regarding the benefits and risks of the selected treatment regimen are essential.

scholarly journals Spontaneous pneumothorax induced by high altitude: A case report

2018 ◽  
Vol 71 (7-8) ◽  
pp. 261-264
Author(s):  
Biljana Lazovic ◽  
Ivana Blazic ◽  
Mirjana Zlatkovic-Svenda ◽  
Vesna Djuric ◽  
Rade Milic ◽  
...  
Keyword(s):  
Case Report ◽  
High Altitude ◽  
Spontaneous Pneumothorax ◽  
Rare Condition ◽  
Primary Spontaneous Pneumothorax ◽  
Low Oxygen ◽  
Professional Athlete ◽  
Physically Active ◽  
Hypoxic Conditions ◽  
Chest X Ray

Introduction. Primary spontaneous pneumothorax is an infrequent condition which requires emergency medical treatment. Nowadays, due to hiking and tourism, many people reach high altitudes in a hypobaric hypoxia environment. These hypoxic conditions can be tolerated if one is exposed to low oxygen pressure, leading to a sequence of physiological responses. Occasionally, hypoxia causes maladaptive responses which leads to different forms of high altitude diseases. Case Report. We report a case of a 49-year-old man, a former professional athlete, passionate about hiking and still physically active. He was admitted to our Emergency Department with short breath and a chest X-ray revealed a large right sided pneumothorax which was successfully treated with tube drainage. Conclusion. Although primary spontaneous pneumothorax is a rare condition, it should be suspected during physical examination. Therefore, physicians should be prepared to recognize it, especially paying attention to all hikers and high-altitude travelers in order to avoid possible risks for high-altitude sickness.

scholarly journals Oxygen-Sensitivity and Pulmonary Selectivity of Vasodilators as Potential Drugs for Pulmonary Hypertension

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 155
Author(s):  
Daniel Morales-Cano ◽  
Bianca Barreira ◽  
Beatriz De Olaiz Navarro ◽  
María Callejo ◽  
Gema Mondejar-Parreño ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Gas Exchange ◽  
Pulmonary Circulation ◽  
Pulmonary Arteries ◽  
Blood Perfusion ◽  
Mesenteric Arteries ◽  
Oxygen Sensitivity ◽  
Low Oxygen ◽  
Oxygen Selectivity

Current approved therapies for pulmonary hypertension (PH) aim to restore the balance between endothelial mediators in the pulmonary circulation. These drugs may exert vasodilator effects on poorly oxygenated vessels. This may lead to the derivation of blood perfusion towards low ventilated alveoli, i.e., producing ventilation-perfusion mismatch, with detrimental effects on gas exchange. The aim of this study is to analyze the oxygen-sensitivity in vitro of 25 drugs currently used or potentially useful for PH. Additionally, the study analyses the effectiveness of these vasodilators in the pulmonary vs. the systemic vessels. Vasodilator responses were recorded in pulmonary arteries (PA) and mesenteric arteries (MA) from rats and in human PA in a wire myograph under different oxygen concentrations. None of the studied drugs showed oxygen selectivity, being equally or more effective as vasodilators under conditions of low oxygen as compared to high oxygen levels. The drugs studied showed low pulmonary selectivity, being equally or more effective as vasodilators in systemic than in PA. A similar behavior was observed for the members within each drug family. In conclusion, none of the drugs showed optimal vasodilator profile, which may limit their therapeutic efficacy in PH.

Effect of low oxygen concentration on activation of inflammation by Helicobacter pylori

2021 ◽  
Vol 560 ◽  
pp. 179-185
Author(s):  
Adiza Abass ◽  
Tokuju Okano ◽  
Kotchakorn Boonyaleka ◽  
Ryo Kinoshita-Daitoku ◽  
Shoji Yamaoka ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Oxygen Concentration ◽  
Low Oxygen ◽  
Low Oxygen Concentration

scholarly journals Sex difference in pulmonary hypertension in the evaluation by exercise echocardiography

2021 ◽  
Vol 11 (1) ◽  
pp. 204589402098845
Author(s):  
Toru Takase ◽  
Mitsugu Taniguchi ◽  
Yutaka Hirano ◽  
Gaku Nakazawa ◽  
Shunichi Miyazaki ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pressure Gradient ◽  
Tricuspid Regurgitation ◽  
Cox Proportional Hazards ◽  
Heart Catheterization ◽  
Exercise Echocardiography ◽  
Poor Survival ◽  
Men And Women ◽  
Low Load ◽  
Male Patients

Male patients with pulmonary hypertension have poor survival than their female counterparts. Poor right ventricular function in men may be one of the major determinants of poor prognosis. This study aimed to investigate the difference in hemodynamics during exercise between men and women by exercise echocardiography. Consecutive patients with pulmonary hypertension who underwent right heart catheterization were enrolled, and survival was analyzed. In patients who underwent exercise echocardiography, the change in tricuspid regurgitation pressure gradient during exercise was calculated at multiple stages (low-, moderate-, and high-load exercise), and the mortality was also recorded. In a total of 93 patients, although there were no differences in pulmonary artery pressure and vascular resistance between sexes, male patients showed poor survival. In patients with exercise echocardiography, change in tricuspid regurgitation pressure gradient at low-load (25 W) exercise was significantly lower in men, although that at maximum-load exercise was not different between men and women. In the Kaplan–Meier analysis, in a median follow-up duration of 1760 days, male patients and those with lower change in tricuspid regurgitation pressure gradient at low-load exercise showed poorer survival ( P = 0.002 and 0.026, respectively). In the Cox proportional hazards analysis, the change in tricuspid regurgitation pressure gradient at low-load exercise was independently associated with poor survival after adjustment for age and sex. In conclusion, a lower change in tricuspid regurgitation pressure gradient at low-load exercise was observed in male patients and was a prognostic marker, which may be associated, at least in part, with poorer prognosis in male patients with pulmonary hypertension.

scholarly journals Pulmonary Hypertension in Acute and Chronic High Altitude Maladaptation Disorders

2021 ◽  
Vol 18 (4) ◽  
pp. 1692
Author(s):  
Akylbek Sydykov ◽  
Argen Mamazhakypov ◽  
Abdirashit Maripov ◽  
Djuro Kosanovic ◽  
Norbert Weissmann ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
High Altitude ◽  
Clinical Experience ◽  
Current Knowledge ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Treatment Options ◽  
Right Heart Failure ◽  
Channel Blockers ◽  
The Right ◽  
Extensive Clinical Experience

Alveolar hypoxia is the most prominent feature of high altitude environment with well-known consequences for the cardio-pulmonary system, including development of pulmonary hypertension. Pulmonary hypertension due to an exaggerated hypoxic pulmonary vasoconstriction contributes to high altitude pulmonary edema (HAPE), a life-threatening disorder, occurring at high altitudes in non-acclimatized healthy individuals. Despite a strong physiologic rationale for using vasodilators for prevention and treatment of HAPE, no systematic studies of their efficacy have been conducted to date. Calcium-channel blockers are currently recommended for drug prophylaxis in high-risk individuals with a clear history of recurrent HAPE based on the extensive clinical experience with nifedipine in HAPE prevention in susceptible individuals. Chronic exposure to hypoxia induces pulmonary vascular remodeling and development of pulmonary hypertension, which places an increased pressure load on the right ventricle leading to right heart failure. Further, pulmonary hypertension along with excessive erythrocytosis may complicate chronic mountain sickness, another high altitude maladaptation disorder. Importantly, other causes than hypoxia may potentially underlie and/or contribute to pulmonary hypertension at high altitude, such as chronic heart and lung diseases, thrombotic or embolic diseases. Extensive clinical experience with drugs in patients with pulmonary arterial hypertension suggests their potential for treatment of high altitude pulmonary hypertension. Small studies have demonstrated their efficacy in reducing pulmonary artery pressure in high altitude residents. However, no drugs have been approved to date for the therapy of chronic high altitude pulmonary hypertension. This work provides a literature review on the role of pulmonary hypertension in the pathogenesis of acute and chronic high altitude maladaptation disorders and summarizes current knowledge regarding potential treatment options.

The Constant Low Oxygen Concentration in All the Target Cells for Mouse Tail Radionecrosis

1982 ◽  
Vol 92 (1) ◽  
pp. 172 ◽  
Author(s):  
J. H. Hendry ◽  
J. V. Moore ◽  
B. W. Hodgson ◽  
J. P. Keene
Keyword(s):  
Oxygen Concentration ◽  
Target Cells ◽  
Low Oxygen ◽  
Low Oxygen Concentration
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