Original ContributionPrevalence and predictors associated with severe pulmonary hypertension in COPD
Introduction
Chronic obstructive pulmonary disease (COPD) is an irreversible bronchial inflammation that involves the lung airways and parenchyma and causes mucociliary dysfunction. Pulmonary hypertension (PH) is a common complication of COPD, which occurs in the wake of the development and exacerbation of the disease in the patients. PH is defined by a resting mean pulmonary arterial pressure > 25 mm Hg, which is measured via right heart catheterization [1], [2], [3], [4]. The prevalence of PH in these patients is different and depends on the severity of the disease, but is usually mild to moderate, and worsens by exercise, sleep and exacerbation of the disease. Approximately 5–10% of patients have “disproportionate” PH, which is the severe form of the disease. In these patients, resting PH is above 40 mm Hg. Such patients—because of the right ventricular failure—have worse prognosis compared with those who have mild to moderate pulmonary hypertension [4], [5], [6], [7].
A method of choice for the diagnosis of PH is right-heart catheterization, but because its nature is aggressive, Transthoracic Doppler Echocardiography can be used as a noninvasive method to screen these patients. In this method, mean pulmonary artery pressure (mPAP) ≥ 40 mm Hg is considered severe PH [3], [5]. The most important factors that can contribute to the occurrence or exacerbation of PH include forced expiratory volume 1 (FEV1), ejection fraction (EF), and body mass index (BMI).
BMI is a measure of body fat and weight. It is calculated by dividing a person's weight in kilograms by the square of their height in meters. A correlation has been established between a high BMI and the increased risk of cardiovascular complications. It has been observed that lower levels of BMI can increase the risk of COPD complications and is inversely related to the survival of these patients, such that a lower BMI increases the risk of mortality caused by COPD [8], [9].
Ejection fraction (EF) is used to assess left ventricular function and is calculated using the biplane Simpson's technique. An EF < 50% is considered left ventricular dysfunction. Patients with COPD are at risk for left ventricular dysfunction; however, the results regarding the association of LV dysfunction in COPD patients has been the subject of much controversy. Nevertheless, the risk of mortality increases in patients with left ventricular dysfunction [10], [11], [12]. It seems that this left ventricular dysfunction is caused by right ventricular heart failure [11].
Lung function in patients with COPD is measured by FEV1 using Spirometry, which enables the assessment of the degree and severity of airway obstruction. A lower value of FEV1 is correlated with a severity of obstruction. In addition, there is a direct correlation between FEV1 levels with the prognosis of these patients [13], [14].
The aim of this study was to assess the prevalence of severe PH in COPD patients referred to the emergency department of Afzalipour hospital and to monitor the relationship between PH with other variables.
Section snippets
Study design
This cross-sectional study was performed at the internal medicine referral center of Kerman Afzalipour Hospital, located in the southeast of Iran, on patients with exacerbated COPD referred to the emergency department from June 21, 2014 through June 21, 2015. In the primary stage of the study, before starting the treatment process, vital signs were measured and complete blood count (CBC) and arterial blood gas (ABG) tests were performed on all the patients. After the patients were stabilized,
Basic characteristics
Of a total of 1477 patients diagnosed with exacerbated COPD referring to the hospital within one year, 399 of them were excluded from the study and 1078 of them included in the study, in which 628 (58.3%) were male and 450 (41.7%) were female. The mean age of the patients undergoing the study was 70.1 ± 12.2. The youngest patient was 39 and the oldest was 93 years old. A total of 136 (13.7%) of them had mPAP (mm Hg) ≥ 40 mm Hg as severe pulmonary hypertension. Also, 129 (12.5%) of them had ejection
Discussion
In this study, the prevalence and predictors associated with severe PH in patients with COPD were examined. According to the results, the prevalence of severe PH in these patients by noninvasive echocardiographic evaluations was 13.7%. Moreover, there was an independent correlation between severe PH, with variables such as hypoxia, hypopnea and compensatory metabolic alkalosis, polycythemia, left ventricular dysfunction, emaciation, and cachectic as well.
The prevalence of severe PH in COPD
Conclusion
The prevalence of severe pulmonary hypertension in this study was reported in 13.7% of patients. The independent factors associated with PH include hypoxia, hypopnea and compensatory metabolic alkalosis, polycythemia, left ventricular dysfunction, emaciation and cachectic in patients.
Conflict of interest
The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.
Acknowledgment
This study was supported by the Clinical Research Center of Afzalipour Hospital [grant number 94.427], Kerman University of Medical Science, Kerman, Iran.
References (31)
- et al.
Pulmonary hypertension in COPD: epidemiology, significance, and management: pulmonary vascular disease: the global perspective
CHEST J.
(2010) - et al.
Pulmonary hypertension in chronic lung diseases
J Am Coll Cardiol
(2013) - et al.
Body mass index and the risk of COPD
Chest J
(2002) - et al.
Co-existence of COPD and left ventricular dysfunction in vascular surgery patients
Respir Med
(2010) - et al.
Left ventricular diastolic dysfunction in patients with COPD in the presence and absence of elevated pulmonary arterial pressure
Chest J
(2008) - et al.
Right and left ventricular dysfunction in patients with severe pulmonary disease
Chest
(1998) - et al.
Predictors of survival in COPD: more than just the FEV1
Respir Med
(2008) - et al.
Prevalence, predictors, and survival in pulmonary hypertension related to end-stage chronic obstructive pulmonary disease
J Heart Lung Transplant
(2012) Pulmonary hypertension associated with left-sided heart disease
Clin Chest Med
(2007)- et al.
Development of pulmonary hypertension in heart failure with preserved ejection fraction
Prog Cardiovasc Dis
(2016)
Impaired left ventricular filling due to right ventricular pressure overload in primary pulmonary hypertension: noninvasive monitoring using MRI
Chest J
The association between obesity, mortality and filling pressures in pulmonary hypertension patients; the “obesity paradox”
Respir Med
Relationships between nutritional status and markers of congestion in patients with pulmonary arterial hypertension
Int J Cardiol
Pulmonary hypertension associated with chronic obstructive lung disease and idiopathic pulmonary fibrosis
Curr Opin Pulm Med
Guidelines for the diagnosis and treatment of pulmonary hypertension
Eur Heart J
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