Echocardiographic Evaluation of Patients with Chronic Obstructive Pulmonary Disease

There is an overlap of risk factors between heart disease and COPD like cigarette smoking, sedentary lifestyle and old age. The economic burden of COPD is also very high. It is now proven that the only strategy which can reduce COPD incidence is cessation of smoking. The Aim of the present research is to study the Two-dimensional transthoracic Echocardiography (TTE) findings in patients with chronic obstructive pulmonary disease (COPD).The method is that all the enrolled patients were subjected to chest radiography, pulmonary function test, Two-dimensional transthoracic echocardiogram and Doppler study, according to the standard protocol. The findings in our study are consistent with previous studies about the COPD. Total 111(60.7%) of the patients had echocardiographic evidence of pulmonary hypertension and 83(45.4%) of the patients in this study had evidence of cor pulmonale. We found significant difference between the duration of smoking and severity of the disease based on FEV1 values (p= 0.005). A significant moderate inverse correlation existed between pack years of smoking and FEV1 scores. (r= 0.379, P < 0.001).


INTRODUCTION
There is an overlap of risk factors between heart disease and COPD like cigarette smoking, sedentary lifestyle and old age. The Lung Health Trial which followed 6000 patients of COPD for 14 years found that FEV1 was an independent factor for predicting the probability of mortality from myocardial infarction [1][2]. Studies have shown high prevalence of heart disease, diabetes and hypertension in patients with low FEV1 values [3][4][5][6]. ECHO is a rapid investigation and gives data about pulmonary hypertension (PH) and structural abnormalities. It has been proven that the estimates of pulmonary arterial pressure by echocardiography are closely corelated with pressures obtained by right heart catheter [7][8][9][10]. Viegi G et al, 2000 reported prevalence of 18.3% among adults of age >25 years in rural areas of north Italy [11]. Danielsson et al, 2012 reported a prevalence of 16.2% in Upsala in adults age >40 years [12]. Saleem et al, 2017, conducted a community based crosssectional study in Madurai district, on 480 participants. Prevalence of COPD was 22.1%. The prevalence in males was 39.2% and females was 12.2%. Prevalence was higher among increasing age, males, illiterate, smokers, poor ventilation and those using biomass fuels [13]. Though COPD is common among older age group, the prevalence in younger age is also of public health importance as they would be continuously exposed to the risk factors. The prevalence of COPD is higher in males than females. COPD prevalence is also high in low BMI cases [13][14][15][16][17][18].
The economic burden of COPD is also very high. It is now proven that the only strategy which can reduce COPD incidence is cessation of smoking [19]. The estimated cost of healthcare associated with COPD is $18 billion direct cost and $14 billion indirect cost [20]. Hospitalizations during an acute episode contribute to 40% of the direct costs and prescription drugs contribute 20% [21]. It is disease which progresses slowly and lung function continues to decline. Persistent cough, dyspnea, wheezing, and chest tightness can be presenting symptoms. Symptoms do not usually occur until FEV1 is approximately 50% of the predicted normal value. Chest radiographs assist in the classification of the type of COPD. Obvious bullae, paucity of parenchymal markings, or hyperlucency on chest X-ray suggests the presence of emphysema. Chest radiographs show no abnormality in at least 21% to 50% of patients with chronic bronchitis. The features that are usually described are those of emphysema, that is, signs of overinflation [22,23].

Aim
To study the Two-dimensional transthoracic Echocardiography (TTE) findings in patients with chronic obstructive pulmonary disease (COPD).

Objectives
1. To assess the cardiac findings secondary to chronic obstructive pulmonary disease by echocardiography. 2. To find out the correlation between echocardiography findings and the severity of chronic obstructive pulmonary disease.

Sample Size Calculation
In the present study the Sample Size is Determined with the help of following method. According to Saleem et al, the prevalence of COPD is 22.1% [13]. Hence, we chose p=22.1 %, q= 1-p i.e. 78%. Using the formula for crosssectional studies, with an absolute precision of 6 percentage points (d) at 95% confidence interval, and p=22.1%, the sample size comes up to 183 patients.

Investigations
All the enrolled patients were subjected to chest radiography, pulmonary function test, Twodimensional transthoracic echocardiogram and Doppler study, according to the standard protocol.

Chest radiograph:
A Chest X-ray PA view was taken in all the patients and the following points were noted.

Spirometry Examination
• Participants were explained the purpose of the test and demonstrated the procedure • Participants made to sit comfortably and to empty the bladder before the procedure • Participants were given following advice during procedure -Breath in until the maximum capacity -Hold the breath and seal the lips tightly around a clean mouthpiece -Blow out the air forcibly and as fast as possible and continue blowing until the maximum capacity.

RESULTS
This study was a cross sectional, observational study conducted in Krishna Hospital and Medical Research Centre, Karad. The study was carried out over a period of 18 months. A total 183 patients diagnosed with chronic obstructive pulmonary disease (COPD) were included in this study to evaluate for echocardiographic changes.  There was significant difference between chest radiograph findings and severity of the disease. They had increased broncho vascular markings, cardiomegaly and pulmonary conus which were present in significantly greater proportion with more severe disease ('p'<0.05). The findings like emphysema showed no significant difference with severity of the disease. There was significant difference between echocardiographic parameters like right atrial size [IS (cm)], right ventricular dilatation, TR gradient, IVC diameter, RSVP and ACT and severity of the disease. They were significantly altered with more severe disease. ('p'<0.05). There was significant difference between severity of the disease and all echocardiographic findings and ('p'<0.05), which were seen significantly altered with increase in severity of disease. There was significant difference between all echocardiographic findings (except ejection fraction and right ventricular wall thickness) and presence of pulmonary hypertension (all 'p'<0.05), which were significantly altered with presence of pulmonary hypertension.
The findings in our study are consistent with previous studies about the COPD.
We found significant difference between the duration of smoking and severity of the disease based on FEV1 values (p= 0.005). A significant moderate inverse correlation existed between pack years of smoking and FEV1 scores. (r= -0.379, P < 0.001) The findings in our study are consistent with previous studies regarding association between smoking and COPD. Therefore, smoking is important predisposing factor for COPD.

Chest Radiograph
On chest radiograph 65% of the patients had features suggestive of emphysema and 76.5% of the patients had increased bronchovascular markings suggestive of chronic bronchitis.
Suma et al and Ghadiya et al also reported similar findings with 80% of the patients having features suggestive of emphysema and 64-66% with increased broncho vascular markings [26,27].
Contrary to our study, Chaudhary and Shrimali reported majority (80%) chest radiograph suggestive of features of emphysema and 68% chronic bronchitis [25]. Other features on chest radiograph in our study were cardiomegaly (36.1%) and pulmonary hypertension (prominent pulmonary conus / prominent right descending pulmonary artery>16mm) in 19.7 % of the patients. Suma et al and Chaudhary and Shrimali reported chest radiograph evidence of pulmonary hypertension in 30% patients each and cardiomegaly in 20% and 24% respectively [26,25].
We found that increased bronchovascular markings, cardiomegaly and pulmonary conus were present in significantly greater proportion with more severe disease (all p<0.05). Our study findings are consistent with above mentioned studies.

Echocardiographic Findings
The following were the echocardiography findings of our study. The ejection fraction was found to be normal in almost all the patients. The right atrial size (IS and TS) was dilated in 52(28.42%) and right ventricular size was dilated in 72(39.34%) patients. The right ventricular wall thickness was suggestive of hypertrophy (>4 mm) in 54(29.5%). Therefore, on echocardiography we found right atrial dilatation in 52(28.42%) and right ventricular dilatation in 72(39.34%) patients. Right ventricular hypertrophy was found in 54(29.5%). Right ventricular failure was seen in 17(9.3%) and interventricular septal motion abnormalities in 31(16.9 %). Evidence of cor pulmonale was seen in 83(45.4%) of the patients and pulmonary hypertension in 111(60.7%). It was found that, all echocardiographic findings were seen significantly in greater proportion with more severe disease (all 'p'<0.05).

CONCLUSION
The cardiac changes due to chronic obstructive pulmonary disease (COPD) and their association with severity of COPD was evaluated in present study. Echocardiographic parameters like right atrial size (vertical section), right ventricular diameter, IVC diameter, RSVP and acceleration time (ACT) were significantly altered with more severe disease. A significant moderate inverse correlation exists between pack years of smoking, duration of symptoms and FEV1 values. Increased broncho vascular markings, cardiomegaly and pulmonary conus were present in significantly greater proportion with more severe disease. There was significant difference between all echocardiographic findings and severity of COPD. There was also significant difference between echocardiographic findings (except ejection fraction, right ventricular wall thickness) and pulmonary hypertension, which were significantly altered with the presence of pulmonary hypertension. We can conclude that, significant echocardiographic changes can be seen in patients of COPD which increases with increasing severity. Echocardiography may help in early detection of cardiac changes due to COPD for early intervention.

CONSENT
As per international standard or university standard, patients' written consent has been collected and preserved by the author(s).

ETHICAL APPROVAL
As per international standard or university standard written ethical approval has been collected and preserved by the author(s).