|Year : 2020 | Volume
| Issue : 2 | Page : 69-75
Group III Pulmonary Hypertension: relative frequency of different etiologies in a referral pulmonary OPD
Parthasarathi Bhattacharyya1, Sayoni Sengupta1, Dipanjan Saha1, Mintu Paul1, Priyanka Choudhury2, Sanjukta Dasgupta2
1 Institute of Pulmocare and Research, Kolkata, West Bengal, India
2 SMST, IIT Kharagpur, Kharagpur, West Bengal, India
|Date of Submission||05-Feb-2020|
|Date of Acceptance||12-Mar-2020|
|Date of Web Publication||10-Sep-2020|
Dr. Parthasarathi Bhattacharyya
Institute of Pulmocare and Research, DG-8, Action area-1, New Town, Kolkata 700156, West Bengal
Source of Support: None, Conflict of Interest: None
Background: The prevalence of pulmonary hypertension (PH) in India remains unknown. The literature is scanty from the country regarding different types of PH. The etiological distribution of Group III PH in a pulmonologist’s practice, therefore, will be worthwhile to note. Method: We included patients with pulmonary hypertension following convenience sampling from those been diagnosed with PH in our pulmonary OPD services on the basis of a novel clinico-radio-echocardiographic criteria. They were then evaluated for the apparent and predominant underlying etiology. Patients with clear and defined diagnosis of COPD, asthma, DPLD, OSA and CTEPH were charted along with those having no obvious etiology but a history of treatment of tuberculosis in the past, along with a group marked as the “others” that consisted of a number of known (sarcoidosis, rheumatic heart disease, etc.) and some incompletely evaluated patients. Results: A total of 356 patients were recruited. The relative frequencies have been accounted to 35.81%, 20.66% and 13.77% for COPD, DPLD and asthma respectively. The patients with a history of TB without any other forthcoming etiology formed 12.67% of the group. The patients with OSA and CTEPH accounted for 2.75% of the group and the “Others” group occupied the rest 14.32%. Conclusion: Group III PH is found not infrequent in pulmonary practice and COPD tops the etiological list.
Keywords: COPD, convenience sampling, echocardiography, pulmonary hypertension
|How to cite this article:|
Bhattacharyya P, Sengupta S, Saha D, Paul M, Choudhury P, Dasgupta S. Group III Pulmonary Hypertension: relative frequency of different etiologies in a referral pulmonary OPD. J Assoc Chest Physicians 2020;8:69-75
|How to cite this URL:|
Bhattacharyya P, Sengupta S, Saha D, Paul M, Choudhury P, Dasgupta S. Group III Pulmonary Hypertension: relative frequency of different etiologies in a referral pulmonary OPD. J Assoc Chest Physicians [serial online] 2020 [cited 2021 Jan 16];8:69-75. Available from: https://www.jacpjournal.org/text.asp?2020/8/2/69/294585
| Introduction|| |
Pulmonary hypertension (PH) is defined as a state of increased pressure in the pulmonary arteries, that carries blood from the heart to the lungs, in order to carry oxygen to the system. The pressure in normal arteries is reported to be 8–20mmHg at rest. In case of PH, the mean resting pulmonary arterial pressure (mPAP) rises to more than 25 mmHg or higher at rest, which is measured by right heart catheterization (RHC).,
The Dana point classification of PH and the subsequent guidelines describes Group III PH to develop from hypoxemia and chronic lung diseases and sleep apnea., In our experience, the condition, though frequent has often been overlooked. This is largely because of non-feasibility of the diagnostic modalities (especially the right heart catheterization) and also the fact of non-availability of effective and easily administered anti-PH therapy in India till the recent time. In short of RHC, we have developed an easy and feasible composite criterion on clinico-radio-echocardiographic parameters to detect PH. We have applied these criteria to diagnose PH, whenever suspected, in our outpatient attendees. Further, we tried to see the common etiologies involved in our patients of PH. Here we present the etiologies of the patients of PH presenting to a referral pulmonary clinic.
| Methods|| |
In a real world scenario, the already worked up patients of a referral pulmonary outpatient department were prospectively selected by a research assistant according to her and the patients’ convenience without any knowledge of the investigator. The investigator’s role was restricted to evaluation to diagnose the basic pulmonary disease, the presence of PH with determination of the predominant etiology for its development. All these were done on objective basis on working algorithms as far as possible.
The prospective selection of patients for the study was done only on procuring the written consent. Strict adherence to the inclusion criteria of the protocol approved by the IEC of the Institute was done. Any candidate patient been diagnosed as having PH with a tenable etiology by the consultant was eligible for inclusion in the research except those been a) unwilling to get enrolled, b) having significant active systemic problem such as myocardial infarction, advanced CLD or CRD, CV accident, etc., c) having history of hospitalization with any cardiopulmonary condition in the preceding four weeks and d) being very sick and debilitated.
The diagnosis of the basic disease
This was accomplished by thorough clinical evaluation and subsequent investigations in a practical and effective algorithm had been used in the institute [see [Figure 1]]. The diagnosis of the primary disease was accomplished on objective basis; the asthmatics were selected after spirometry following GINA and the COPD patients following GOLD guidelines. The diagnosis of DPLD was ascertained through spirometry and HRCT chest; OSA and CTEPH were included on diagnosis through polysomnography and pulmonary perfusion scan in suspected cases. The exercise was applied according to the real-world situation as there was no sponsorship for the job and investigations were aimed to as minimal as possible.
|Figure 1 Algorithm for the diagnosis of lung diseases (modified from Dasgupta et al.).|
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Diagnosis of PH
Diagnosis of PH was accomplished on the basis of novel clinico-radio-echocardiographic criterion that has been practiced in our institute. The criteria include the mandatory presence of at least one positive reply from each of the features (clinical, chest x-ray, HRCT and Doppler Echocardiography) as presented below.
Clinical symptoms of PH
- Unexplained SOB (Shortness of Breath) and SOB disproportionate to clinical or radiological (chest x-ray) findings.
- Demonstration of desaturation at rest or with mild exercise by pulse oximeter without any obvious airway or parenchymal diseases.
- Other symptoms as unexplained fatigue, syncope, etc.
- Dilated right main pulmonary artery in PA view.
- Fullness of the retro-sternal space from right ventricular enlargement in lateral view.
- Gross PA dilation/ fullness of pulmonary bay.
- Pulmonary artery root diameter ≥aortic root diameter.
- Pulmonary artery branch diameter ≥accompanying bronchial diameter in three or four lobes.
Estimated pulmonary artery systolic pressure ≥ 40 mm of Hg. The echo-doppler studies were done in a single center, by a single expert following a uniform protocol for all the patients. In the process of diagnosis and the measurement of PASP the measurement of TR (tricuspid regurgitation) peak velocity; peak PR (pulmonary regurgitation) by Doppler signal, pulmonary diastolic pressure by end velocity, right ventricular outflow by acceleration time, right ventricular isovolumic relaxation time, and Tei index by tissue doppler were considered as per the recommendation by literature.,
The determination of the etiology of PH
The determination of the etiology of PH was accomplished following the algorithm practiced at the institute [Figure 2] and [Figure 3].
|Figure 2 Algorithmic approach to unfolding the etiological diagnosis of PH (modified from the ECS-ERS guidelines, according to real world scenario).|
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|Figure 3 Relative percentage of PH patients with different etiologies attending IPCR.|
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The predominant etiology (as perceived by the investigator) has been taken as the primary cause although more than one condition could be coincidental and contributing to the development of PH in a particular patient. In the process of inclusion, as the investigator was blinded, PH candidates not belonging to class III (e.g., rheumatic heart disease, PAH) and having respiratory problems (e.g., bilateral pleural effusion, ABPA with scar, etc.) not clearly mentioned in the list of conditions of class III PH were entertained.
Assessment of other parameters
All the patients included in the study have been screened according to the protocol for (a) the functional status (according to WHO) and (b) quality of life in terms of CAT test
The patients included were organized according to the following etiological groups as: COPD, DPLD, asthma, OSA and CTEPH, history of TB and an others group. The TB associated PH has been included from one of our previous publication. The other parameters included in the evaluation were mean age, BMI, smoking index, mean pulmonary arterial pressure, CAT score, etc. [as mentioned in [Table 1].
|Table 1 The patients of PH in different groups of etiologies are charted|
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| Results|| |
The study included the selection of patients for the study period from 2 February 2013 to 29 December 2016, where 1745 patients were diagnosed with PH (mostly group III) in the institute. Out of them 355 patients were included through convenient sampling by a research assistant.
| Discussion|| |
There have been certain noteworthy observations and they are the first of its kind in the country. The study reveals that COPD is the most common entity to cause Group III PH (36.59%) followed by DPLD (21.34%) and Asthma (14.04%) respectively [see [Table 2]. A clear female predominance was observed in case of DPLD and Asthma but a male predominance was reported in case of COPD. The TB associated PH patients were the youngest (mean age= 57.17±13.6) while those with COPD were oldest (mean age = 66.1±7.7). As per the arterial oxygen saturation (SpO2) is concerned, the lowest saturation at rest was observed in case of DPLD patients followed by COPD, TB associated PH and the group marked as “Others” respectively [[Table 2].
|Table 2 The causes of PH in the group other than the major listed ones (marker as “others”)|
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It was observed that the TB associated patients behaved like COPD as far as the spirometric lung function is concerned. As expected, the lowest FVC was observed in case of DPLD and lowest FEV1 was observed in case of COPD and the FEF25-75 was reported to be worst in case of COPD and TB associated PH.
The average PAP pressure for COPD was recorded to be 46.97±10.5, DPLD 49.46±12.9, asthma 44.38±5.6, patients with TB associated PH was reported to be 45.4±8.3, OSA 53.3±22.7 and the others group marked to be 52.64±14.51 respectively. The following inferences are deduced from the study:
The average systolic PAP pressure for COPD was recorded to be 46.97±10.5, DPLD 49.46±12.9, asthma 44.38±5.6, patients with TB associated PH was reported to be 45.4±8.3, OSA 53.3±22.7 and the others group marked to be 52.64±14.51 respectively.
CAT has been considered as a well-accepted and validated tool for the assessment of COPD, and has also been applied to DPLD. The association of PH in DPLD has been well known., Although the assessment through CAT score appears rational, its use has not been validated for PH or any other case of lung disease. This instrument has been adapted for its simplicity in application and also for maintaining uniformity in the assessment for all the categories mentioned above. The component of CAT also applies very well for patients with a non COPD pathology.
In our observation, the patients were selected purely on the basis of convenience sampling or the availability sampling. Convenience sampling is a statistical method for deriving representative data by selecting people, due to the ease of volunteering or selecting units, according to their easy availability and easy access.,, The selection is unlikely to be affected from any serious biasness since the investigator was not involved in the procedure of inclusion of the patients.
The innovativeness in the whole exercise has been that the diagnostic exercise for PH is accomplished without performing the right heart catheterization. The peculiarities listed under each category of clinico-radio-echocardiographic criteria have been considered important for the diagnosis of PH. The dilation of the pulmonary arteries at the hila and the obliteration of the pulmonary bay, are signs of the presence of PH in chest X-ray. Likewise, the obliteration of the retro-sternal space on lateral view is also suggestive of RV dilation for PH. In HRCT chest, the demonstration of dilated pulmonary trunk having the root diameter turning more than the adjacent aortic diameter and the width of the pulmonary artery branches looking wider than the diameter of the adjacent bronchi in three or more lobes are highly predictive of the presence of PH (specificity and sensitivity 100%). Therefore, the presence of PH in the selected patients of ours was absolutely certain but there can be argument regarding the determination of the exact pulmonary arterial pressure. The determination of the mean pressure from the peak pulmonary systolic pressure can be calculated using regression analysis. Furthermore, we have made our own algorithm modifying the ECS-ERS guideline laid one that befits our reality. A CAT score above 12 is certainly an indicator of poor quality of life. Despite having the highest PA pressure (53.3±22.7 mm of Hg.), the patients with CTEPH and OSA had the lowest CAT score of 12±4.66 suggesting the possibility of a hypoxemic insult of smaller duration or lesser magnitude. This area needs explanation. The CAT score in all other conditions was above 14 and in DPLD it was above 16 (16.63) indication possible worst quality of life status.
There are several rooms for criticism in this study. The diagnosis of PH, although established in our opinion, was not supported by the right heart catheterization, which is regarded as the “gold standard” for the purpose. Hence, we cannot state the exact PA pressure based on echocardiographic value as echocardiography has several limitations. The relative frequency of PH in our study actually represents the situation in a tertiary pulmonary OPD; it has limited epidemiological value. We have noted the investigator perceived predominant etiology, hence, the other co-incidental etiologies could have been neglected in some patients. The evaluation for the OSA by sleep study and the same for CTEPH were done in selective cases with very index of suspicion as the evaluation exercises were not sponsored. This, to our mind, it may have given a lower frequency of the presence of these entities. CAT is valid tool for the measurement of the quality of life in COPD patients. It is also successfully tested in DPLD. The validity of CAT score beyond COPD and DPLD has not been tested so far; therefore, the PH specific scoring system (e.g., emPHasis score) whenever possible should have been tried. Incidentally the protocol started before the advent of EmPHasis. The poor CAT score status of these patients suggest that there should have been some guideline for intervention and the scientists should explore for making a suitable indication algorithm for treating the class III PH.
Finally, the observation leaves us with many questions and makes us aware to look more methodically at Group-III PH in practice. This may help us in improving the quality of life for a large number of patients with Group-III PH in our community.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]