Pulmonary hypertension is an underrecognized complication in patients with ILDs and can adversely affect symptoms, functional capacity, and survival. Connective tissue disease-related ILD, sarcoidosis, idiopathic pulmonary fibrosis, and pulmonary Langerhans cell histiocytosis are the ILDs most commonly associated with PH [1].

Pulmonary hypertension can arise in patients with ILDs through various mechanisms, Including pulmonary vasoconstriction and vascular remodeling, vascular destruction associated with progressive parenchymal fibrosis, vascular inflammation, perivascular fibrosis, and thrombotic angiopathy. Diagnosis of PH in these patients requires a high index of suspicion because the clinical presentation tends to be nonspecific, particularly in the presence of an underlying parenchymal lung disease [1].

Pulmonary hypertension is hard to diagnose early because it's not often detected during a routine physical exam. Even when the condition is more advanced, its signs and symptoms are similar to those of other heart and lung conditions [2].

To diagnose pulmonary hypertension, a pysician will perform CXR ,HRCT and ECG and review other signs and symptoms. A chest X-ray creates pictures of the heart, lungs and chest. It can show enlargement of the right ventricle or the pulmonary arteries. A chest X-ray may also be used to check for other lung conditions that can cause pulmonary hypertension. Electrocardiogram (ECG) is noninvasive test shows the heart's electrical patterns and can detect abnormal heartbeats. An ECG may also reveal signs of right ventricle enlargement or strain. Computerized tomography (CT) creates cross-sectional pictures of the bones, blood vessels and soft tissues inside the body. A CT scan can show the size of the heart and any blockages in the pulmonary arteries. This test may be used to look more closely for lung diseases that might lead to pulmonary hypertension such as COPD or pulmonary fibrosis. CT is also used to diagnose and phenotype suspected ILD, and is often part of the workup of patients with unexplained breathlessness and suspected PH [2-4].

There is paucity of studies on the Pulmonary artery hypertension (PAH) and it’s association with Radiological and Electrocardiogram (ECG) findings among patients diagnosed with interstitial lung diseases (ILD), in this hilly area of northern India. The present study was done to evaluate the association of Radiological and Electrocardiogram (ECG) findings with Pulmonary artery hypertension (PAH) among Interstitial Lung Diseases (ILDs) patients.

Aims and Objectives

• To study the association of Radiological and Electrocardiogram (ECG) findings with Pulmonary artery hypertension (PAH) among Interstitial Lung Diseases (ILDs) patients

The present study was conducted at Indira Gandhi Medical College, Shimla which is a tertiary care center of Himachal Pradesh, located in North India in Asian Continent and covers the majority of the population of this state. All consecutive patients of Interstitial Lung Diseases (ILDs), attending the outpatient services of the Department of Pulmonary Medicine, IGMC Shimla from July 2018 to June 2019 were screened for enrolment in the study. All types of ILDs were enrolled in the study.

Inclusion Criteria

• Stable ILD patients: diagnosis of ILD according to ATS/ERS guidelines based on an overall assessment of high-resolution computed tomography (HRCT) scan, lung function tests, (bronchoscopy and biopsy, if available.) 

• Age >18 years, written consent

Exclusion Criteria

• Subjects with evidence of left heart disease, Chronic kidney disease, Liver disease

• Chronic lung diseases other than ILDs

• Patients with HIV.

• Pregnant

Patients presenting with respiratory symptoms such as cough, shortness of breath and diagnosed cases of ILD were evaluated.

All consecutive ILD patients were subjected to focused history and physical examination as structured questionnaire record information related to; Demographics, Duration of ILD, Pulmonary artery hypertension (PAH) and its Association with Radiological and Electrocardiogram (ECG) findings etc.

The data was collected, entered in the MS Excel sheet and analyzed using Epi info V7 software. Continuous variables were reported as Mean ± SD or median and interquartile range depending on the distribution of the variables. Categorical variables were recorded as counts and percentages. Differences between means of continuous variables were compared using the unpaired student’s’ test. A p-value of <0.05 was considered as statistically significant.

Among the study population, 50 patients 27 54% were female and 23 46% were male. The mean age of the study population was 57.821+5.03years. The mean age of males and females was 62.561+3.84 years and 53.771+5.07 years respectively. The mean duration of symptoms of ILD was 3.034+2.62 years. There was no significant difference between males and females regarding the duration of illness (2.76+2.46 years versus 3.39+2.77 years, p = 0.40) Table 1.

Table 1: Age and Gender Distribution of the Study Population (N = 50)

Pulmonary artery hypertension (PAH) was by derived Pulmonary flow acceleration time formula (PFAT) .Those who had Mean pulmonary artery pressure (MPAP) >25 mmHG was diagnosed as PAH case. Out of 50 patients, 44 88% had PAH. 

Out of 50 patients, 36 64% had this x-ray finding, among patients who had PH there were 31 70.45% patients had a reticular shadow on chest x-ray, with a p-value of 0.01 .Out of 50 patients, there were 27 61.36% patients had reduced lung volume. Among PH group 27 61.76% had reduced lung volume with a p-value of 0.006.Out, 50 patients, there were 14 28% had right pulmonary artery prominence. Among PH group 14 31.82% patients had this radiological feature, with a p- value of 0. 12.

Out of 50 patients, there were 27 54% with UIP pattern, among patients who had PH there were 25 57.52% in number. Out of 50 patients there were 13 23.6% had NSIP pattern, among patients who had PH there were 10 22.73% in number .One (2%) patient with CPFE had PH. Out of 50 patient 9 18% of sarcoidosis, 7 15.19% patients had PH, with a p-value of 0.3.

Out of 50 patients, P-pulmonale was present in 24 48% patients. Among them, 22 50% were in the PH group, with a p -value of 0.37.Out 50 patients, the 23 patient had RAD. Among them, 21 47.37% were in the PAH group, with a p- value of 0.41.Out of 50 patients 23 46% had RVH. 21 47.73% in the PH group, with a p value of 0.41 Table 2.

Table 2: Association of Radiological and Electrocardiographic Findings with PAH

The association of ILD with Radiological and Electrocardiogram (ECG) findings was analyzed to determine the risk determinants of PAH.

The mean age of the study population was 57.821+5.03 with male and female mean age 62.561+3.84 and 53.77+15.07 respectively. Females were more than male and younger with a mean duration of ILD of 3.034±2.62 years. A similar finding was also reported in the study conducted by Agarwal et al. [5]. In the ILD registry of Indian data, it was reported that ILDs occur at a younger age compared to the western countries, and females are affected more [6].

In our study, the majority of the patients had a chest x-ray feature of reticular shadow 70% (p = 0.01). R. Agarwal et al. [5] in their study reported a similar finding among 88.9%, in their study sample size was small and the study was done only among IPF patients.

In our study, the majority of patients had a chest x-ray feature of reduced lung volume 61.65% in patients with PH group, with a p-value of 006. Our study was done in patients of various types of ILD). Agarwal et al. [5] reported similar comparable results. In our study chest, the x-ray feature of right pulmonary artery prominence was less in number among patients with PH group. 

In our study majority of patients had a UIP pattern in HRCT in patients with PH group. Various studies in the literature reported a similar finding. Agarwal et al. [5] in their study reported similar HRCT findings. The majority in our study had IPF patients, so results comparable.

In our study ECG findings like p–pulmonale, Right axis deviation (RAD) and right ventricular hypertrophy (RVH) were recorded. P-pulmonale was present in 50% of patients with PH group. RAD was observed in 47.73% and RVH was present at 47.73%. 

There was very high prevalence of PAH among ILD Patients. There was very high prevalence of PAH among ILD Patients. CXR findings like reticular shadow, reduced lung volume and right pulmonary artery prominence, HRCT findings like UIP pattern, NSIP pattern, CPFE and sarcoidosis and ECG findings like P-pulmonale, RAD and RVH were more in Pulmonary artery hypertension patients. But there was no statistically difference among various Radiological and Electrocardiogram (ECG) findings.

Limitations of the Study

The small number of the population were included in this study represents a methodological limitation and study over a larger population is recommended. 

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