Introduction
Cor-pulmonale can be defined as an alteration in structure (e.g., hypertrophy or dilatation) and function (i.e failure) of the right ventricle secondary to primary disorder of the respiratory system resulting in pulmonary hypertension. Cor-pulmonale occurs secondary to many broncho-pulmonary vascular diseases and from different chest wall abnormalities. Cor pulmonale can be a fatal disease and it accounts for high incidence among hospital admission for heart failure. The development of PAH has important prognostic role, as it significantly increases the risk of hospitalization and is associated with reduced survival.
In most reported series, more than 50%of cases are due to chronic bronchitis, emphysema1, 2, 3.
It is difficult to estimate prevalence of cor-pulmonale because, all patients with chronic lung disease will not land in cor-pulmonale, and our ability to diagnose PAH and cor-pulmonale by physical examination and lab investigations alone is relatively insensitive. Therefore, it is apparent that cor-pulmonale can be diagnosed collectively clinically, radiologically, electrocardiographically and echocardiographically.
This study was conducted to know the clinical manifestations, radiological features, electrocardiographic and echocardiographic changes in various lung diseases landing in cor-pulmonale.
Materials and Methods
A Prospective observational study during one year period from November 2018 to November 2019.100 patients of cor-pulmonale confirmed by clinical manifestations, radiological features (chest X-ray), and electrocardiographic changes from outpatient and inpatient in pulmonology department, Government General Hospital, RMC, Kakinada. An ethical committee approval was taken.
Inclusion criteria
All patients of both genders with clinical features like dyspnea, recurrentchest infections, fluid retention and general physical examination suggestive of right ventricular failure like raised JVP, hepatomegaly and bilateral pedal edema with right ventricular hypertrophy or dilation in ECHO.
Exclusion criteria
Patients with following conditions are excluded as they themselves can lead to right ventricular failure and might affect the investigational changes:
Primary involvement of left heart (valvular or myocardial disease, arterial occlusive disease, primary pulmonary hypertension, congenital heart disease, gross anemia with heart failure) or Chronic liver disease or Chronic kidney disease.
Results
The following observations were made in 100 study cases of cor-pulmonale.
Table 1
Age distribution among study group: The age group ranged between 24 to 85 years in the study group.
| Age in years | No. of cases | Percentage |
| <40 | 09 | 9% |
| 40-50 | 16 | 16% |
| 51-60 | 40 | 40% |
| >60 | 35 | 35% |
Table 3
Smoking association among study group: Most of the patients were chronic smokers.
| Smoking history | No of Male cases | No. of female cases | Percentage |
| Present | 63 | 7 | 70% |
| Absent | 9 | 21 | 30% |
Table 4
Association with smoking duration among smokers:
| No. of Pack years | No. of cases | Percentage |
| <10 | 25 | 35.71% |
| 11-20 | 10 | 14.28% |
| 21-29 | 22 | 31.42% |
| >29 | 13 | 18.57% |
Table 5
Association with Past History of Tuberculosis:
| Past H/O tuberculosis | No. of cases | Percentage |
| Present | 29 | 29% |
| Absent | 71 | 71% |
Table 6
Symptomatology among study Group:
Table 7
Distribution of physical findings among study group:
Table 8
Association of Cor-pulmonale among study group:
Table 9
Distribution of radiological features among study:
Table 10
Distribution of ECG Findings among study group:
| ECG changes | No. of cases | Percentage |
| P pumonale | 89 | 89% |
| Right axis deviation | 66 | 66% |
| Low voltage complexes | 31 | 31% |
| RBBB | 28 | 28% |
| Right ventricular hypertrophy | 22 | 22% |
| Arrhythmias | 35 | 35% |
Table 11
Distribution of Echocardiography changes:
| Severity of PAH based on RVSP in mm of Hg (normal<35) | No. of Cases | Percentage |
| Mild (35-45) | 18 | 18% |
| Moderate (46-60) | 26 | 26% |
| Severe (>60) | 56 | 56% |
All patients showed enlarged right atrium and right ventricle with pulmonary artery hypertension either associated with trivial or moderate tricuspid regurgitation. 8 patients who were known cases of COPD with hypertension showed global hypokinesia. Associated left ventricular dysfunction was found in 23 cases.
Table 12
Distribution of RVID-ED (Right Ventricular Internal Diameter At End Diastole) among Study Group:
| RVID-ED (mm) | No. of Cases | Percentage |
| 27-28 mm | 9 | 9% |
| 29-33 mm | 12 | 12% |
| 34-38mm | 31 | 31% |
| >38mm | 48 | 48% |
RVID-ED more than 26mm indicates dilatation of right ventricle. Thus echocardiographic evaluation is found to be a reliable noninvasive method of assessing right ventricular function.
Discussion
In the present study the peak incidence was found to be in the 5th and 6th decades of life as most of the patients started smoking in third decade cumulative damage to the lung took over decades and this is well comparable with that of cases studied in Babu et al., (2013)1 study where most cases are between 50-59 years. The incidence of cor-pulmonale below the age of 40 was also highwhich can be attributed to environmental pollution, as well as smoking habit started earlier in life.
Males (72%) are predominant gender in present study than females(28%) which is similar to Senthil kumar et al2. study group. The prevalence of cor-pulmonale among females in present study might be due to increasing prevalence of more tobacco smoking(owing to urbanization and westernization of society), biomass fuel(used to cook meals)exposure, indoor air pollution.
In present study 70% were smokers which closely resembles to Padmavathi et al., study4 (70%), Kumar et al., study5(71%), Rao et al., study6 (76%).Out of 70% smokers, 63% were males and 7% were females. This can also be the reason of more prevalence in males. Many patients smoked cigars and beedis, which donotcontain tobacco filter and have high tobacco content. 38% of study group had pack years >10. In Kumar et al., study2, majority 96(54%) were smokers and out of which majority 70(72.92%) are smoking for more than 10 years. This strong association between smoking and cor pulmonale can be attributed to the development of COPD, progressing to cor—pulmonale over years. This finding is also consistent with many studies where smokers are more prone to COPD which exacerbates into COPD and then to heart failure.
In the present study 100% of the patients presented with shortness of breath, cough and peripheral edema. 39% has distension of the abdomen. According to Babu et al 1.,(2019), Kumar et al 5.,(2009), Thakkeret al 3.,(2014), Rao et al 6., breathlessness and cough were present in 100 % cases. In present study fever accounts for 30%, which is comparable to Rao et al. study 6., (24%) which is attributed to infective process secondary to viral or bacterial etiology in a previously damaged lung parenchyma. In present study, loss of appetite is present in 66% of cases which indicates that the disease is a chronic process. This is nearer to Rao et al study 6., and Kumar et al., study 2. 4% cases had hemoptysis suggesting underlying bronchiectasis.
In present study tachypnea, accessory muscle usage, pedal edema, either rhonchi or crepitations or both and decreased chestexpansion and signs of right heart failure are present in 100% cases, clinically suggesting the presence of cor-pulmonale. According to Kumar et al., study 2, tachypnea, rhonchi and crepitations were present in all the cases.
JVP is raised in 75% of cases in present study which correlated with previous studies. In Kumar et al., study5, raised JVP (88.3%) was the commonest sign Kapoor et al.,[32] noted that the most constant physical sign leading to consideration of cor pulmonale in patients with absent symptoms and clinical signs was the presence of a loud P2. According to Thakker et al., study3, Raised JVP, enlarged liver and pedal edema were present in majority of patients suggestive of congestive cardiac failure. Loud P2 is seen in 90% patients in present study which correlates well with Kumar et al2.study.
Barrel shaped chest present in 21% cases in present study. Some patients showed signs of loss of lung volume which can be attributed to various underlying causes for cor pulmonale like fibrosis, post tuberculosis sequel, thoracic cage deformities.
the present study showed 60% patients had chronic bronchitis with or without emphysema which was leading cause for cor pulmonale similar to findings of Babu et al1., Kumar et al2., and Thakker et al3.,.
In present study tuberculosis is the 2nd leading cause for development of cor-pulmonale accounting for 19% patients. Post tubercular sequeale in the form of fibrosis with destruction of vascular bed due to parenchymal abnormalities, vasculitis, endarteritis, reduced cross sectional area of pulmonary vasculature and distortion of architecture of pulmonary artery, vascular remodeling leads to development of pulmonary hypertension and cor-pulmonale subsequently.
In Kumar et al., study 5, among all the causes of cor pulmonale, pulmonary tuberculosis and COPD combined or either independently is responsible for major causative diseases of cor-pulmonale accounting for 88 patients (86.1%) of the total cases.
Table 13
Comparison of Radiological Findings with Various Studies:
In present study most frequently found radiological finding is increased broncho vascular makings with or without hyper inflated lung fields (46%) which suggest a differential diagnosis of chronic bronchits, emphysema and bronchial asthma. Our study shows similar results with various studies conducted previously.
Comparision of ECG changes in various studies
Table 14
Comparative percentage of p pulmonale in different studies
| Study | Percentage |
| Thakker et al., 3 | 58% |
| Rao et al., 6 | 28% |
| Kumar et al. 2 | 71% |
| Present study | 89% |
p-pulmonale had definite correlation with severity of chronic cor-pulmonale and was found in majority of cases who had longer duration of illness. In present study RBBB present in 28% cases which is similar to Babu et al., study 1 (26%) and Kumar et al., 2(32%).
Though ECG has its limitations, it can still be useful in diagnosing cor pulmonale. ECG can also be used as a negative prognostic sign in targeting COPD patients at risk of shorter survival.
Various studies demonstrate that level of pulmonary hypertension is a prognostic indicator in cor-pulmonale. In present study PAH present in 100 % cases. Mild in 18%, moderate in 26% and severe in 56% cases. Echocardiography showed an enlarged right atrium, right ventricle and right ventricular hypertrophy with pulmonary artery hypertension either associated with trivial or moderate tricuspid regurgitation in every patient. Left ventricular dysfunction is present in 23% of cases.
Table 15
Comparing PAH in different studies
| Study | Percentage |
| Thakker et al., 3 | 96.67% |
| Babu et al., 1 | 100% |
| Kumar et al., 2 | 100% |
| Present study | 100% |
Based on pulmonary hypertension categorization and proper treatment initiation at right time, we can prevent the progression of disease. By keeping the patients on follow-ups and based on 2D ECHO findings, we can prevent the disease progression. As 2-D Echo is less invasive and repeatable, it acts as better prognostic tool.
Table 16
Comparing RVID-ED in Studies
| Study | Mean RVID-ED in mm |
| Babu et al.,(2013) 1 | 35.2 mm |
| Goswami et al.,(2017) 8 | 37.07mm |
| Agarwal et al.,(2017) 7 | 36.4mm |
| Present study | 37.27mm |
In present study mean RVID-ED is 37.27 mm, which is very well comparable to various previous studies. In present study right ventricular diameter in severely abnormal range in 48% cases. In Goswami et al., (2017) study7 RVID-ED is 37.07±5.21.In the study by Agarwal et al., 8. mean RVID-ED of 40.2 ± 5.6 mm, which is in the moderately abnormal range of RVID-ED.
Echocardiography is found to be a reliable method to assess right ventricular function. Doppler echocardiography is most useful with specificity and sensitivity of about 80%. Advances in echocardiography make this a useful test where cor pulmonale is suspected.
Conclusions
We would thus suggest that echocardiographic screening of all patients with chronic lung disease would help in early detection of disease and earlier initiation of treatment, thus improving their prognosis.
Instead of going for invasive cardiac catheterization, a combined clinical, radiological, ECG and echocardiographic findings can give clue about progression of PAH and cor-pulmonale.
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