|Year : 2018 | Volume
| Issue : 2 | Page : 71-76
Echocardiographic findings in Nigerian patients with stroke
Jamila Ado Ya'u1, Kamilu Musa Karaye2, BN Okeahialam3
1 Department of Medicine, Public Health and Diagnostic Institute, Yusuf Maitama Sule University Hospital, Kano State, Nigeria
2 Department of Medicine, Bayero University Kano, Aminu Kano Teaching Hospital, Kano State, Nigeria
3 Department of Medicine, Jos University Teaching Hospital, Plateau State, Nigeria
|Date of Web Publication||3-Jul-2019|
Dr. Jamila Ado Ya'u
Department of Medicine, Public Health and Diagnostic Institute, Yusuf Maitama Sule University Kano
Source of Support: None, Conflict of Interest: None
Stroke is the third leading cause of death in several industrial countries and cardio-embolism accounts for 15–30% of ischaemic strokes. Studies investigating associations between echocardiographic parameters and stroke mechanisms are limited. This study therefore aimed at assessing echocardiographic parameters and left ventricular (LV) functions in stroke patients in comparison with apparent healthy controls. This was a case-control study conducted at Aminu Kano Teaching Hospital Kano, Nigeria. 100 stroke subjects were consecutively recruited and compared with 100 age and sex matched controls. Echocardiographic parameters studied include LV and Left atrial (LA) dimensions, LV hypertrophy (LVH), LV systolic and diastolic dysfunctions, regional wall motion abnormalities (RWMA), intracardiac thrombus, and valvular diseases using transthoracic echocardiography. The mean age of cases and controls was 56.4 ± 15.8years and 54.5 ± 15.4 years (P = 0.39), and M:F ratio was 1.1:1 among both cases and controls (P = 0.887). LVH was the most prevalent echocardiographic finding; found in 62% and 21% (P<0.01) of the cases and controls, respectively. Concentric LVH was found in 42% of the cases and 13% of controls, eccentric LVH in 23% of cases and 9% of the controls, while concentric remodeling was found in 5% of cases and 2% of controls (P < 0.001, 0.002 and 0.272 respectively). LV systolic dysfunction was found in 10% of the cases and 3% of the controls (P = 0.044), LV diastolic dysfunction in 48% of the cases and 18% of the controls (P < 0.001), while combined systolic and diastolic dysfunction was found in 12% of cases and 4% of the controls respectively (P = 0.038). Regional wall motion abnormality, Increased LA size, Aortic valve sclerosis and rheumatic valvular heart disease were commoner amongst cases than controls. Echocardiographic abnormalities were common among stroke patients and their presence could influence clinical decisions and outcomes. This study therefore supports echocardiographic evaluation of stroke patients.
Keywords: Dysfunction, echocardiography, hypertrophy, left ventricle, stroke
|How to cite this article:|
Ya'u JA, Karaye KM, Okeahialam B N. Echocardiographic findings in Nigerian patients with stroke. Nig J Cardiol 2018;15:71-6
| Introduction|| |
Stroke is the major cause of serious long-term disability and the third cause of death in developed countries. About 15%–30% of all ischemic strokes are caused by emboli, usually arising from the heart.
The search for a cardiac cause or source of thromboembolism is one of the most frequent indications for a transthoracic echocardiographic study (TTE). A previous study in the southwestern Nigeria has revealed cardioembolic source as more common in the younger age group with intracardiac source of embolism in 26% of all cases, left ventricular hypertrophy (LVH) was the most common echocardiographic finding present in 76% of the cases, although LV function was not characterized in the study. However, few data are published on TTE in patients with stroke in Nigeria.
Hence, this study aimed to determine the pattern of echocardiographic abnormalities as well as describe LV systolic and diastolic functions in stroke patients in comparison to healthy controls.
| Methodology|| |
This was a case–control study conducted over a period of 20 weeks (August 15,2011–December 15, 2011) at Aminu Kano Teaching Hospital (AKTH), Kano, Nigeria.
Before the commencement of the study, the study protocol was approved by the Ethics Committee of AKTH. Informed written consent was obtained from all patients, and for those who could not sign a thumbprint was taken or consent was signed by a next of kin. The HELSINKI declaration on investigations of human subjects was respected.
Patients with stroke admitted into the emergency and the medical wards of the hospital satisfying the inclusion criteria were recruited consecutively until the sample size was obtained. Control group was formed by individuals without stroke presenting to the general outpatients (GOP) clinic with minor ailments and were investigated similarly as were the cases. The two groups were matched for age and gender.
Inclusion criteria for the cases were as follows: admission to the medical wards or the emergency unit with stroke as defined by the World Health Organization criteria, and presenting within the first 7 days of the event; the age of 18 years and above, and giving informed consent to participate in the study. Patients <18 years of age, or those who did not have stroke, declined consent or who presented after the first 7 days of stroke were excluded from the study.
The inclusion criteria for the control group were - patients who presented to GOP with minor ailments but who have never suffered a stroke, aged 18 years and above, and who gave consent to participate in the study. GOP patients <18 years, or who have had a stroke or who declined consent were excluded.
A 12-lead electrocardiogram (ECG) at rest was carried out for each individual by the investigator using Bionet Cardiocare EKG-2000 machine (made in South Korea) at the Diagnostic Center of AKTH. This was done after the first 3 days of stroke and on initial contact in the controls. Electrodes were placed according to the AHA recommendations.
TTE was performed by the researchers (JAY, KMK) on all the individuals using ALOKA SSD-4000 machine. Two measurements were obtained for each individual, and the average value was used. Patients were examined in the left lateral decubitus positions using the parasternal long axis, parasternal short axis (mid-level) with the transducer at the 3rd–4th intercostals space, and apical two and four chamber views with the transducer at the cardiac apex. M-mode echocardiography, two-dimensional (2D), and 2D directed pulsed-wave and continuous-wave Doppler recordings were obtained by standard methods.,
Echocardiographic risk factors for stroke were sought, in addition to baseline data. Attention was paid to LVH, intracardiac thrombus, valvular heart diseases, the presence of septal-defect, vegetations, LV systolic and diastolic dysfunction, left atrial (LA), and LV dimensions. Heart diseases considered include hypertensive heart disease (HHD), cardiomyopathies, ischemic heart disease, and valvular heart diseases.
All measurements were taken according to the recommendations of the American Society of Echocardiography. LVH was considered present if: LV mass index (LVMI) >96 g/m 2 in females and >115 g/m 2 in males. Left ventricular geometric patterns were defined using relative wall thickness (RWT) and LVMI. RWT was calculated as: two (LV posterior wall thickness in diastole)/(LV internal diameter at end-diastole [LVIDd]). Increased RWT was defined as values >0.43. Normal geometry was defined as the presence of normal RWT and normal LVMI; concentric remodeling defined as increased RWT and normal LVMI; concentric LVH is defined as increase LVMI with increased RWT; eccentric LVH is defined as normal RWT and increased LVMI. Dilated LA and LV were defined as >3.8 cm and 4.0 cm in females and males, >5.3 cm and >5.9 cm in females and males, respectively.
Left ventricular systolic dysfunction
This was defined as the LV ejection fraction (LVEF) <50%.
Left ventricular diastolic dysfunction
This was defi ned as – Normal diastolic filling pattern: Defined as values of E/A = 1–1.5; deceleration time (DT) = 160–240 ms; isovolumetric relaxation time (IVRT) = 70–90 ms. Grade 1 diastolic dysfunction (impaired relaxation): Defined as reduced E/A <1.0; prolonged DT >240 ms and IVRT >90 ms. Grade 2 diastolic dysfunction (pseudo-normal pattern): Defined as increased E/A 1–1.5; DT <160 ms and IVRT ≤90 ms Grade 3 diastolic dysfunction (restrictive filling pattern): Defined as E/A >1.5; reduced DT <160 ms and IVRT <70 ms. (E = early rapid fi lling wave; A = filling wave due to atrial contraction; DT = deceleration time; IVRT = isovolumetric relaxation time).
Ischemic heart disease
Ischemic heart disease was diagnosed based on the combination of the documented history of chest pain, ECG abnormalities, and segmental wall motion abnormalities.
Hypertensive heart disease
This was diagnosed in a patient with preexisting systemic hypertension, the presence of any cardiac abnormality that was causally related to hypertension and without an alternative explanation, on the ECG or and echocardiography.
Rheumatic heart disease
The diagnosis was made using the World Heart Federation criteria.
Dilated cardiomyopathy was defined by the presence of dilated left ventricle (with or without dilation of the other 3 cardiac chambers) with global systolic and diastolic dysfunctions.
Atrial fibrillation was defined by the presence of the ECG of the absence of P-waves and irregular R-R Interval due to irregular conduction of impulses to the ventricle.
Data were collected using a pretested semi-structured interviewer-administered questionnaire which was administered by YJA.
Data were collected from all the 200 patients in data sheets, and then explored for skewness and analyzed using Statistical Package for Social Sciences (SPSS) version 19 (IBM SPSS, Armonk, New York, United States). Median with interquartile ranges, Chi-square, Fisher's exact probability, Student's t-test, and Mann–Whitney U-tests were used to compare categorical and continuous variables as appropriate. Value of P ≤ 0.05 was considered to be statistically significant.
| Results|| |
A total of 100 stroke patients were consecutively recruited into the study and compared with 100 age- and sex-matched controls.
The mean age for the cases was 56.4 ± 15.8 years and 54.5 ± 15.4 years for the controls (P = 0.39). Among cases, 53% were male and 47% were female, whereas in the control group 52% were males and 48% were female (P = 0.887). Hypertension was present in 71% of the cases and 42% of the controls (P < 0.001), while diabetes mellitus was present in 23% of the cases and 6% of the controls (P < 0.01). Dyslipidemia was found in 53% of cases and 37% of the controls (P < 0.023), while atrial fibrillation was found in 9% of cases only. Use of recreational drugs was found in 2% of cases and 1% of the controls while combined oral pills were used by 2% of cases and 4% of the controls, P = 0.560 and 0.414, respectively.
Increased LA size was present in 23% of cases and 6% of the controls (P < 0.001), while increased LV size was present in 10% of the cases and 7% of the controls (P = 0.338). LV diastolic dysfunction was present in 48% of cases and 18% of controls (P < 0.000), LV systolic dysfunction was found in 10% and 3% of cases and controls, respectively (P = 0.044), both systolic and diastolic dysfunction found in 12% and 4% of cases and controls, respectively (P = 0.038) valvular disease in 30% and 12%, respectively (P = 0.02). LV thrombus was present in 5% of cases and none in the controls, regional wall motion abnormality (RWMA) was seen in 6% of the cases and 1% of the controls, respectively (P < 0.005), LVH 62% and 17% in the cases and controls, respectively, P < 0.002.
The mean LA size for the cases was 39.6 ± 10.3 mm, while that for the controls was 36 ± 6.31 mm, P = 0.008. The mean LVIDd for the cases was 48.1 ± 10.7 mm while that of the control group was 48.38 ± 0.78 mm, P = 0.65. Mean LVEF of the study cases was 62.3 ± 15%, while that for controls was 67 ± 9.58%, (P = 0.009).
Among the heart diseases, HHD was the most common, seen in 55% of the cases and 18% of the controls, P < 0.0001. Echocardiography was done on all the cases and the controls.
Echocardiographic parameters are presented in [Table 1], abnormal echocardiographic findings are presented in [Table 2], whereas LV geometric pattern is presented in [Figure 1].
|Table 1: Mean values of echocardiographic parameters in the study population|
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|Figure 1: Left ventricular geometric pattern in the study population. n – Values expressed as numbers with percentages expressed as brackets; LV – Left ventricle|
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| Discussion|| |
The present study assessed the echocardiographic abnormalities and the LV systolic and diastolic functions in stroke patients in comparison to apparent healthy controls. Echocardiographic abnormalities were found to be more common in stroke patients than the controls. In addition, LV systolic and diastolic dysfunctions increased LA and LV sizes, RWMA, LV thrombus and LVH were significantly more frequent among the stroke patients.
LV systolic dysfunction was found among 22% of stroke patients in the present study. This has been associated with ischemic stroke across a wide range of LV systolic dysfunction severity. A retrospective analysis from the study of LV dysfunction trial found an increased risk of thromboembolic events associated with low LVEF, particularly with severely decreased LVEF, but only in women. In the survival and ventricular enlargement trial, every decrease by 5% in LVEF was associated with an 18% increase in stroke risk in the first 5 years after myocardial infarction. Patients with LVEF of 28% or less had a relative risk of stroke of 1.86 compared with patients with LVEF of >35% (P = 0.01).
The mechanism underlying the association between LV systolic dysfunction and stroke is not immediately clear. One possibility is that LV systolic dysfunction promotes increased blood stasis in both the LV and left atrium, increasing the chance of thrombus formation and the risk of embolic stroke. This is further demonstrated in our study which revealed that 5% of stroke patients had LV thrombus, and 23% had dilated LA. LV thrombus has been shown to be associated with thromboembolic diseases such as stroke., In the survival and ventricular enlargement trial, the incidence of stroke was 1.5/100 patient/years, and the risk was higher in older patients with lower EF. The relationship between LA diameter and stroke subtype has been further characterized with atherothrombotic associated with milder dilation and cardioembolic stroke occurring at a greater dilation.
LV dilatation was present in 10% of the cases and 7% of the controls. These results were in agreement with those of Canada 8% but higher than the findings reported from Pakistan 1.8%., LV dilation and ischemic cardiomyopathy were found to be independent predictors of LV thrombus formation. There was a consistent, graded relationship between increasing chamber size and the presence of LV thrombus. Furthermore, there was an association between increasing chamber size and peripheral thromboembolism irrespective of the presence or absence of LV thrombus.
RWMA was seen in 6% of the cases and 1% of the controls. Similar prevalence of 7.6% was obtained in Pakistan, but the much higher prevalence of 19.7% was reported in Canada., The prevalence of RWMA reflects the emerging incidence of ischemic heart disease in the developing world more so in Kano where previous reports revealed that it accounted for 3.4% of cardiovascular admissions.
LV diastolic dysfunction was observed in 48% of cases and 18% of the controls. Diastolic dysfunction has been related to increased mortality in the presence or absence of systolic dysfunction. LV diastolic dysfunction has been found to deteriorate the functional status of the patient over the course of stroke recovery and may increase the risk of recurrent vascular events in ischemic stroke survivors. LV diastolic dysfunction, even in asymptomatic cases, may impede exercise capacity, which is a vital requirement for functional recovery after stroke.
LVH was significantly high among stroke patients, this concurs with previous studies in Spain, Pakistan, and a recent Nigerian study.,, LVH might be a marker of subclinical disease or predispose to other conditions directly involved in stroke etiology. The EUROSTROKE project indicates that LVH assessed by ECG is a predictor of stroke. The association seems to be stronger for fatal stroke than for nonfatal stroke and is more pronounced in smokers. LVH also predicts cognitive dysfunction where the subclinical stroke is a potential contributor., It is even included as a predictor in several stroke risk profiles including the Framingham  and the atherosclerosis risk in communities study. Although most studies on LVH were done in Caucasians, our study has shown its role in the etiology in stroke in Negroes. This further buttresses the fact that LVH is a risk factor across all ethnicity. In the present study, concentric LVH was the most common LV geometric pattern, followed by eccentric LVH and then concentric LV remodeling in the cases. However in control, normal geometry was the highest finding; then concentric LVH, followed by eccentric LVH and then concentric remodeling. The difference between the groups was statistically significant. The findings in the present study are in agreement with the work by Di Tullio et al. who found concentric LVH to have the highest association with stroke.
The most prevalent valvular disease detected was aortic valve sclerosis found in 27% of the cases and 10% of the controls. Similarly, Rem et al. in Canada found a prevalence of AV sclerosis in 31.1% of stroke patients. Clinical factors associated with aortic sclerosis include age, male gender, hypertension, elevated serum levels of lipoprotein(a) and low-density lipoprotein, smoking, and diabetes., Dyslipidemia and hypertension have been previously documented to be common in the population studied as reported by the NCD survey.
Rheumatic heart valvular disease was found in 8% of the cases and 2% of the controls. Higher rates were reported from Canada 14.75% where pure mitral stenosis (MS) was 11.47% in a study two decades ago, but currently, it is on the decline. However, rheumatic MS with dilated LA was found in 6% of the cases, in the present study. Khan et al. in Pakistan reported the prevalence of MS in 2.5%, and MS with dilated LA in 1.8%. The difference observed might be due to differences in sample size in studied populations.
The strength and limitations
The strengths of the present study were a case–control study including a sizeable number of stroke patients that looked at the echocardiographic parameters and LV function between stroke patients and apparently healthy controls. The limitation of the study includes – nonavailability of transesophageal echocardiography has more sensitivity in detecting LA and valvular lesions than TTE.
| Conclusion|| |
This study demonstrated that the echocardiographic variables associated with stroke were more common in stroke patients as compared with controls. Dilated LA and LV, LVH, RWMA, LV systolic and diastolic dysfunction, and mural thrombus were more common in stroke than controls.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]