|Year : 2017 | Volume
| Issue : 2 | Page : 127-130
Update on rheumatic heart disease in Kano: Data from the Aminu Kano Teaching Hospital echocardiography registry
Umar Abdullahi1, Shehu Abubakar Kana2, Muzammil Muhammad Yakasai2, Nasir Ahmad Ishaq2, Jamila Ado Yau3, Hadiza Saidu4, Muhammad Sani Mijinyawa5, Kamilu Msa Karaye5, Mahmoud Umar Sani5
1 Department of Medicine, Ahmad Sani Yariman Bakura Specialist Hospital, Gusau, Nigeria
2 Department of Medicine, Aminu Kano Teaching Hospital, Kano, Nigeria
3 Public Health and Diagnostic Institute, North West University, Kano, Nigeria
4 Department of Medicine, Murtala Muhammad Specialist Hospital; Bayero University, Kano, Nigeria
5 Department of Medicine, Aminu Kano Teaching Hospital; Bayero University, Kano, Nigeria
|Date of Web Publication||5-Oct-2017|
Department of Medicine, Ahmad Sani Yariman Bakura Specialist Hospital, Gusau
Source of Support: None, Conflict of Interest: None
Background: Rheumatic heart disease (RHD) remains a major public health problem in developing countries. Anecdotal reports across Africa show that the disease is coming less prevalent in the cities and the patients are surviving longer, although with a lot of morbidity. Between 2002 and 2006, 9.8% of 1312 patients were found to have RHD from our echocardiographic registry, with a mean age of 24 years. Therefore, we set out to review our current data for RHD to see if there are any changes in patterns of presentation in our center. Materials and Methods: This is a retrospective analysis of a prospectively collected echocardiography data between August 2010 and July 2012. The study was conducted at the Aminu Kano Teaching Hospital, Kano Nigeria. The procedure was performed with Aloka SSD 4000. The standard techniques for depicting the anatomical structures of the heart were employed. All echocardiographic procedures were performed by a cardiologist. Information obtained from the records included the age, gender, clinical diagnoses, and echocardiographic diagnoses. Prevalence and patterns were compared with previous findings. Results: During this period, a total of 1496 echocardiographic examinations were done. One hundred and four (7.0%) had RHD. There were 69 females (66.3%) and 35 males (33.7%) aged 30.7 + 14.0 years (range 12–70 years). Forty (38.5%) were aged 15–24 years. The commonest lesions were mixed mitral valve disease and aortic regurgitation (26.9%) followed by combination of mitral and aortic regurgitation (25%), and pure mitral regurgitation in 17.3%. Complications of RHD observed included secondary pulmonary hypertension (50%), left ventricular dysfunction (40.4%), atrial fibrillation (AF) (8.7%), infective endocarditis (1.9%), and intra cardiac thrombus (1.9%). Conclusion: RHD is still an important cause of cardiac morbidity. Although there is a reduction in prevalence compared to previous finding in the same center, while the patients are a bit older, they had more severe disease and still had complications at diagnosis.
Keywords: Kano, rheumatic heart disease, update
|How to cite this article:|
Abdullahi U, Kana SA, Yakasai MM, Ishaq NA, Yau JA, Saidu H, Mijinyawa MS, Karaye KM, Sani MU. Update on rheumatic heart disease in Kano: Data from the Aminu Kano Teaching Hospital echocardiography registry. Niger J Basic Clin Sci 2017;14:127-30
|How to cite this URL:|
Abdullahi U, Kana SA, Yakasai MM, Ishaq NA, Yau JA, Saidu H, Mijinyawa MS, Karaye KM, Sani MU. Update on rheumatic heart disease in Kano: Data from the Aminu Kano Teaching Hospital echocardiography registry. Niger J Basic Clin Sci [serial online] 2017 [cited 2019 Sep 22];14:127-30. Available from: http://www.njbcs.net/text.asp?2017/14/2/127/216047
| Introduction|| |
The World Health Organization (WHO) estimates that acute rheumatic fever (ARF) and subsequent rheumatic heart disease (RHD) affect about 15.6 million people worldwide., RHD remains a major public health problem in developing countries. Whereas, Africa has 10% of the world population, as many as half of the 2.4 million children affected by RHD globally live on the continent. It accounts for a major proportion of all cardiovascular disease in children and young adults in African countries and, by extension, in the world, because 80% of the world's population lives in developing countries where the disease is still endemic. The disease has the potential to undermine national productivity since it affects the most productive part of the population.
The most important complication of ARF is fibrosis of the heart valves, leading to altered hemodynamics, chamber remodeling, and the clinical syndrome of heart failure (HF) require open heart surgery to replace or repair the damaged heart valves. If left untreated, subsequent HF and or death is almost inevitable.
The major determinants of ARF and RHD are poverty, malnutrition, overcrowding, poor housing, and shortage of healthcare resources., Although cost-effective strategies for the prevention and control of these diseases are available, they remain under-utilized in most developing countries.,
Over the past century, as living conditions have become more hygienic, less crowded, nutrition and access to medical care have improved, ARF and RHD have become rare in developed countries. The introduction of antibiotics has also helped to reduce the burden of disease, although to a lesser extent than these other factors., ARF and RHD are now largely restricted to developing countries and some poor, mainly indigenous populations of wealthy countries.
While ARF is said to be on the decline even in the developing world, we are burdened with a large number of chronic RHD cases. These patients exhibit chronic congestive HF and recurrent thromboembolic phenomena both posing greater challenges for management.
We set out to review our current data for RHD to describe the prevalence and echocardiographic pattern of RHD in Kano, the most populous city in the Nigerian savannah region and to compare with the previous finding to see if there are any changes in prevalence and patterns of presentation from the same center.
| Materials and Methods|| |
This is a retrospective analysis of a prospectively collected transthoracic echocardiography (TTE) data over 24 month (August 2010 and July 2012) which was reviewed. Patients with echocardiographic diagnosis of RHD were selected. The study was conducted at the Aminu Kano Teaching Hospital, located in Kano, northern Nigeria. The procedure was performed with Aloka SSD 4000. The standard techniques for depicting the anatomical structures of the heart were employed. All the echocardiographic procedures were performed by a cardiologist. Information obtained from the records included the age, gender, clinical diagnoses, and echocardiographic diagnoses. Data were analyzed using Statistical Package for Social Sciences (SPSS) for windows version 18.0 (July, 30 2009) by IBM company in Chicago, Illinois.
Echocardiographic modalities applied included M-mode, two-dimensional (2D), and Doppler studies. Echocardiography was done with 3–5 MHz sector transducer. Complete 2D echocardiographic examination was performed according to the recommendations of the American Society of Echocardiography (ASE). M-mode echocardiograms were derived from 2D images. The M-mode cursor on the 2D scan was moved to specific areas of the heart to obtain measurement according to the recommendation of the committee on M-mode standardization of the ASE. Doppler indices of left ventricular (LV) diastolic filling were obtained. Complete Doppler study was done according to the recommendations of the ASE.
From the M-mode measurements, indices of LV function were derived. These included shortening fraction, ejection fraction, left ventricular mass, cardiac output, and relative wall thickness. Echocardiographic examinations included valvular architecture, left atrial size, left ventricular size, and function, a semi-quantitative estimate of the severity of valvular regurgitation, size and function of the right ventricle, and evidence of pulmonary arterial hypertension.
Mitral stenosis was diagnosed on the presence of thickening of anterior mitral valve leaflet (≥3 mm in case of ≤20 years, ≥4mm in case of 21–40 years, ≥5mm in case of ≥40 years), chordal thickening, excessive leaflet tip motion during systole, and restriction of leaflet motions, with a mean gradient ≥4 mmHg, mitral valvular area of ≤4 cm 2, and pressure half time of ≤500 ms.,,, Mitral regurgitation was diagnosed in the presence of thickened valves, dilated mitral valve annuli, left atrium (LA), and left ventricle (LV) are usually dilated and lack of cooptation of mitral valve leaflets in systole, with vena contracta of ≥3 mm, regurgitant volume of ≥30 mL, regurgitant fraction of ≥30%, and effective regurgitant orifice area of 2 mm2. Doppler echocardiographic analyses identified the presence and severity of regurgitation of the aortic and mitral valves. Doppler evidence of regurgitation seen in two views, measured of jet length ≥2 cm for mitral regurgitation or ≥1 cm for aortic regurgitation in at least one view, velocity ≥3m/s for one complete envelope, pan-systolic jet in at least one envelope in the presence of thickened valves.,,, Thickened and calcified aortic valve leaflets with reduced leaflet motion (aortic cusp separation less than 9 mm) suggested aortic stenosis, with trans aortic peak velocity of 2.5 m/s, mean pressure gradient of ≥25 mmHg, and aortic valvular area of ≤2 cm2.,,, In addition, there could be concentric left ventricular hypertrophy (LVH) and decreased LV ejection performance.
Other abnormalities like evidence of pulmonary arterial hypertension were also noted. The pulmonary artery systolic pressure (PASP) was estimated by measuring the maximum velocity of the tricuspid regurgitant velocity (TRV), the trans-tricuspid pressure gradient was then calculated using the modified Bernoulli equation 4(TRV) 2. The right ventricular systolic pressure (RVSP) was calculated using the formula: RVSP = 4(TRV) 2 + right atrial pressure (RAP). The TRV was measured from the continuous wave Doppler of tricuspid regurgitant jet from apical four-chamber or from the parasternal right ventricular inflow view if the regurgitant jet was eccentric. The PASP is equivalent to RVSP in the absence of pulmonary outflow obstruction. The RAP is estimated by the respiratory variation size of the inferior vena cava in M-mode.
| Results|| |
During the study period, a total of 1496 echocardiographic examinations were done in the study center. One hundred and four (7.0%) patients had echocardiographic diagnosis of RHD. There were 35 males (33.7%) and 69 females (66.3%) ratio 1: 2 which mean age of 30.7 ± 14.0 years (range 12–70 years).
[Table 1] shows age and sex distribution of the study subjects. The highest prevalence of RHD was in the 15–24 years age group constitute of 40 (38.5%) followed by 25–34 years with 32 (30.8%) and four patients were in sixth decade. Female presented more at older age 25 (36.2%) at 25–34 years than male 18 (51.4%) at 15–24 years.
|Table 1: Age and sex distribution of patients with rheumatic heart disease in Aminu Kano Teaching Hospital, Kano, Nigeria|
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The commonest lesions were mixed mitral valve disease and aortic regurgitation (26.9%) followed by combination of mitral and aortic regurgitation (25.0%) and pure mitral regurgitation in 17.3% as shown in [Table 2].
|Table 2: Distribution of type of rheumatic heart disease by gender in Aminu Kano Teaching Hospital, Kano, Nigeria|
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The complications of RHD observed were included secondary pulmonary hypertension (50.0%), left ventricular dysfunction (40.4%), atrial fibrillation (AF) (8.7%), infective endocarditis (1.9%), and intracardiac thrombus (1.9%).
| Discussion|| |
Nigeria like other developing countries is still having significant prevalence of RHD because of poor housing, overcrowding, poverty, malnutrition, shortage of healthcare resources, and inadequate prophylactic penicillin therapy. RHD was found to account for 7.0% of cardiac disease found at echocardiography in this study with mean age of 30 years compare to 9.8% with mean age of 24 years in the previous study from the same center. A similar finding of 7.3% was found by Talle et al. in Maiduguri, North east Nigeria. However, a higher value of 9.2%, 11.0% and 25.1% were was found in Port Harcourt Nigeria, Uganda and Zimbabwe respectively.,, While, RHD is still present in our center, the present study shows some reduction in the prevalence when compared to our previous study. This may reflect better access to primary healthcare, less overcrowding, better sanitation and use of antibiotics in the treatment of streptococcal throat infection, and ARF. The increase in the mean age in this study suggests that the burden imposed by RHD is present throughout the life course, with many cases surviving to present in the older age group.
In many populations, ARF and RHD are more common in females than males. This has also been shown in this study and previous studies.,,, Whether this trend is a result of innate susceptibility, increased exposure to group A streptococcus because of greater involvement of women in child bearing or reduced access to preventive medical care for girls and women is unclear.
Mixed mitral valve disease and aortic regurgitation were the commonest valvular affectation in 28 (26.9%) of the patients followed by combination of mitral and aortic regurgitation 26 (25.0%), pure mitral regurgitation in 18 (17.3%), and mixed mitral valve disease in 9 (8.7%) of the study patients in contrast to the previous study from the same center where pure mitral regurgitation was the commonest echocardiographic diagnosis in 49 (38.0%) of the patients, followed by mixed mitral valve disease in 36 (27.9%) then mixed mitral, and mixed aortic valve disease in 25 (19.5%). A similar finding was recently found by investigators from Maiduguri. They also documented mixed mitral valve disease and aortic regurgitation to be the commonest valvular affectation in their series.
The reason for change in the pattern of valvular affectation in our center is not very clear. However, it might be that our patients are surviving longer than in the previous study and are able to cope with RHD affecting multiple valves. In addition, most patients present to tertiary care hospital with advanced disease, which is the situation in our case.
Pulmonary hypertension is usual complication in patients with left sided valve disease and recorded in 50.0% of the patients in this study similar to what we previously reported. Secondary pulmonary hypertension is due to reactive changes in the pulmonary vascular resistance. In left sided valve disease, the LV becomes hypertrophic and less distensible, leading to increased LV end-diastolic pressure. This causes increased work of the LA, leading to enlargement of the LA. The enlarged LA causes decreases cardiac output and pulmonary hypertension results.
Left atrial enlargement frequently results from mitral valve and to a lesser extent aortic valve disease. AF may complicate left atrial enlargement and was seen in 8.7% of our patients in this study. AF leads to loss of organized mechanical activity of the LA and increases the tendency to develop spontaneous echo contrast and thrombus. Intracardiac thrombus was seen in 1.9% of our study patients. This might have been underestimated as TTE has limitations in detecting the presence of left atrial thrombi. Transesophageal echocardiography (TEE) is more valuable in detecting cardiac thrombi, especially if the thrombus is less than 5 mm or occurs in the left atrial appendage.
There is need to increase awareness of the public and healthcare workers with regard to ARF and RHD, improvement of healthcare facilities needed to treat and prevent the disease. In addition to established national primary and secondary prevention programs for ARF and RHD.
| Conclusion|| |
RHD is still an important cause of cardiac morbidity. Although, there is a reduction in prevalence compared to previous finding in the same center, while the patients are a bit older, they had more severe disease and still had complications at diagnosis. There is need to need to increase awareness of the public and healthcare workers with regard to ARF and RHD.
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Conflicts of interest
There are no conflicts of interest.
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