Assessment of pulmonary function in coronary artery disease

 

Mohd Amir Khan¹, Prashant D Purkar^2*, S T Nabar³, Ashana Rafique Parbalkar⁴

 

¹Sr. Resident, ²Associate Professor, ³Professor, ⁴Intern, Department of Medicine, Dr. D Y Patil Medical College, Navi Mumbai, Maharashtra, INDIA.

Email: prashpurkar@gmail.com

 

Abstract              Background: Cardiovascular diseases (CVDs) are a group of disorders of the heart and blood vessels and comprise CAD. CVDs are the number one cause of death globally. CAD is responsible for mortality and morbidity in developed and developing countries. It is a leading cause of death in India. Aim and Objectives: To assess pulmonary function among established stable coronary artery disease patients Material and methods: It’s a prospective study conducted in Department of General Medicine after obtaining permission from the Institutional Ethics Committee. The duration of study was 2 years i.e. from January 2015 to December 2016. Inclusion and exclusion criterias were adequately defined. Pulmonary Function Test was performed in the morning. Daily calibration of the machine using manual calibration syringe as per ATS specification is done. Results: A total of 117 patients were recruited in this study, out of which 64 were males and 53 were females. Females are commonly affected in 40-50 years of age while, for >50 year ages, males are more commonly affected. Out of the total patients evaluated, 54 had abnormal PFT‘s whereas 63 had normal. When the type of pulmonary condition among study participants with CAD is considered, significantly more number of patients have restrictive pattern (29.06%) as compared to obstructive pattern (17.09) of pulmonary function. Conclusions: There were significantly more number of patients had restrictive pattern of pulmonary function. As the mortality of CAD and obstructive/ restrictive disease is rising in India, along with the current practices of prevention and management of CAD patient serial PFT‘s can be a feature to be included in the follow up of these patients.

Key Words: Coronary Artery Disease, Pulmonary Function Test.

 

INTRODUCTION

Coronary Artery Disease (CAD), also well-known as ischemic heart disease (IHD) is one of the types of heart disease which is caused by inadequate supply of oxygen and blood toa portion of myocardium. The narrowing of arteries, due to cholesterol, builds up in the inner layers of the arteries, which slow down the blood flow and supply of oxygen. As a result, cardiac muscles do not get enough blood supply.¹ The current World Health Organization (WHO) report, predicted around 7.4 million people to die due to CAD.²Although there are regional variations that influence the extent of economic development and social organization, the global prevalence of CAD-related clinical manifestations is still increasing. Its contribution to mortality is expanding: the number of deaths due to CAD in 1985 is expected to have doubled by 2015.³ The CAD rates in large Indian cities are reported higher than that of Indians living overseas. In rural India, the prevalence of CAD doubled to 3-4%, while in urban India it quadrupled to 9-11%over the past four decades.⁴ CAD risk factors fall into modifiable and non-modifiable categories. Non-modifiable risk factors such as age, family history, ethnic origin, gender cannot be altered. Modifiable risk factors can be altered by changing behaviour patterns or lifestyle, and through the administration of prescribed drugs. CAD risk factors include elevated serumtotal and low density lipoprotein cholesterol (LDL-C), low high-density lipoproteincholesterol [HDL-C], diabetes mellitus (DM), low level of physical activity, smoking, obesity, sedentary lifestyle, dyslipidemia and systemic arterial hypertension.⁵ Various studies have described pulmonary function-related changes in patients with chronic left ventricular dysfunction and heart failure. Lung functions deteriorate as a complication of CAD or impairment of lung function is a risk factor for the development of CAD is still not understood. The main objective of this study was to assess the pulmonary functions in stable patients ofCAD.⁶

 

MATERIAL AND METHODS

It’s a prospective study conducted in Department of General Medicine, D Y Patil University School of Medicine, Nerul, Navi Mumbai, Maharashtra. The study began after obtaining permission from the Institutional Ethics Committee. All patients included in the study with stable CAD i.e. 117, were explained the purpose and rational of the study as well as their role as participants in the study. The duration of study was 2 years i.e. from January 2015 to December 2016. Written informed consent was obtained from all the patients prior to enrolling them in the study.

Inclusion Criteria

Patients with following criteria were selected for this study

1. Established adult CAD cases. (Past or present ECG changes/ stress test proved/2-D Echo/Angiographically proved)
2. Stable CAD for the last 2-6 years.
3. Controlled hypertension

Exclusion Criteria

Patients with following criteria were excluded from study

1. Patients having any attack of angina or MI in the recent past (within 3 months).
2. Patients having any previous history of asthma, COPD, tuberculosis,ILD
3. Patients having any history of smoking.
4. Patients having CCF/LVF.
5. Patients having uncontrolled hypertension.
6. Patients have occupational or environmental lung disease.
7. Patients who had prior lung surgery, bronchiectasis.

A predesigned and pretested proforma was filled from all patients and the information collected from each patient enrolled in the study recorded on a Case Record Form (CRF).Haematological investigations like Complete blood count was done. Also, X-Ray chest, ECG and 2D-echo were performed. Pulmonary Function Test was performed in the morning. Prediction equations for spirometry in adults of Indian origin using the 2005 American Thoracic Society/European Respiratory Society (ATS/ERS) was used. Daily calibration of the machine using manual calibration syringe as per ATS specification is done. All data were collected in a Data Collection Form and then transferred to an Excel sheet. The SPSS-version 16 software (SPSS Inc., Chicago, IL, USA) was used for data entry and analysis.

 

RESULTS AND OBSERVATIONS

 

Tables 1: Age wise and gender wise distribution of study participants with CAD

Using Chi Square test, P value- <0.0001

A total of 117 patients were recruited in this study, out of which 64 were males and 53 were females. Since p value is<0.05, there is significant difference between proportion of subjects in different age groups. Females are commonly affected in 40-50 years of age while, for >50 year ages, males are more commonly affected. Overall there is no difference between proportion of total male and female.

 

Table 2: Comparison of past history and treatment modality followed among study participants with CAD

Using Chi Square test, in each of the case, p value is >0.05 i.e. there is no significant difference between proportion of male or female presenting with significant past history.

 

Table 3: Comparison of demographics among study participants with CAD

 

Using unpaired t test, for height and BMI, P value is <0.05 i.e. males having significantly more height and lower BMI as compared to females. Average BMI for males was 23.8 whereas average BMI for females was 25.68. It was apparent from the study that pulmonary function is negatively correlated with BMI, as BMI increases pulmonary function decreases.

 

Table 4: Pulmonary Function Test results among study participants with CAD

Out of 117 patients evaluated, 54 had abnormal PFT‘s whereas 63 had normal. These patients had no prior pulmonary risk factors, hence such a high proportion of abnormal PFT in these patients was significant. Using Sign and Binomial Test, out of 117 stable CAD patients with no prior pulmonary risk factor 46.15% patients had abnormal PFT, which is significant.

 

Table 5: Comparison of type of pulmonary condition among study participants with CAD

Using Sign and Binomial Test, p value is <0.05 which shows that, significantly more number of patients have restrictive pattern (29.06%) of pulmonary function as compared to obstructive pattern (17.09%) of pulmonary function.

 

Figure 1: Comparison of type of pulmonary condition

Out of the 20 patients who had obstructive pattern, 9 had mild, 7 had moderate and 4 had moderately severe obstruction. Out of the 34 patients who had restrictive pattern, 9 had mild, 14 had moderate and 12 had severe restriction. Significantly more proportion of males have mild to moderate and female have moderately severe, severe and very severe restrictive type of pulmonary function.

 

DISCUSSION

CAD is a leading cause of death in India and the burden of mortality due to CAD is rising and was projected to have doubled in 2015 compared to 1985.⁷ The incidence of CAD in young Indians has been reported to be between 12%–16%, with half of the CVD-related deaths (i.e., 52%) in India occurring below the age of50 years.⁸ Lung functions deteriorate as a complication of CAD or impairment of lung function is a risk factor for the development of CAD is still not understood. Different studies revealed different results but lung functions were found to be impaired in CAD patients. These patients are undergoing invasive procedures like CABG and angioplasty, so it should not add to their morbidity and mortality and hence the evaluation of pulmonary functions is important in these patients.⁹ In the present study, there were a total 117 patients were recruited in this study, out of which 64 were males and 53 females and a significantly more number of patients have restrictive pattern (29.06%) of pulmonary function as compared to obstructive pattern (17.09) of pulmonary function. Among the 34 patients who had restrictive pattern, 9 had mild, 14 had moderate and 12 had severe restriction. A study conducted by Asha Yadav found almost all the parameters of PFTs to bedeteriorated in CAD patients when compared to normal healthy controls. Statistically significant reduction in FVC, FEV1, PEFR, and MVV indicate that a combination of restrictive (stiff lungs) and obstructive (cardiac asthma) derangements in lung function occur in CAD patients even after medication and stable for 2-6 years.¹⁰ A study conducted by El-Sobkey SB concluded that rheumatic and ischemic cardiac diseases as well as valvular and CABG cardiac surgeries result in low PFTs values of restrictive pattern.¹¹A study conducted by Sonkamble Siddharth has shown that around one in fivepatients (19%) with CAD have concomitant COPD. On evaluating the association of various demographic and clinical characteristics of patients with COPD it was found that increasing age (> 60 years), severe cardiac abnormality (NYHA Class II/ III), diastolicdys function and history of smoking were significantly associated with increased risk ofCOPD.¹² About the global burden of disease, study has projected that by the year 2020the prevalence athero-thrombotic cardiovascular disease in India willsurpass that of any other region in the world.¹⁰ Additional PF Tabnormality will enhance the morbidity and mortality in these patients. Hence over attempt was to exclude occupational, post-tuberculous, smoker or any form of pulmonary health hazard and our intention was to see whether deteriorated cardiac function is in some way responsible for PFT abnormalities.

 

CONCLUSIONS

Study included 117 patients who had no established pulmonary pathology but had established CAD. PFT‘s was performed in each of these patients. Females were commonly affected with IHD in 40-50 years of age; whereas males were more commonly affected when age was >50.Out of total, 52 patients were managed with angioplasty and 58 patients were managed with CABG. Remaining 7 were only on medical therapy. Among the total 117 stable CAD patients, 54 patients had abnormal PFT. Significantly more number of patients had restrictive pattern of pulmonary function as compared to obstructive pattern of pulmonary function. As the mortality of CAD and obstructive/ restrictive disease is rising in India, along with the current practices of prevention and management of CAD patient serial PFT‘s can be a feature to be included in the follow up of these patients.

 

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