17 / 61
CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 4, July/August 2021
AFRICA
189
Conformity of the data to normal distribution was assessed with
the Kolmogorov–Smirnov test. Continuous data are presented as
mean ± standard deviation (SD) or median [range, interquartile
range (IQR)], and categorical data as number (
n
) and percentage.
Categorical parameters were analysed with the chi-squared
test, and continuous variables with a normal distribution with
the unpaired
t
-test. The Mann–Whitney
U
-test was applied to
continuous variables with a non-normal distribution. Multiple
linear regression analysis was applied to determine independent
determinants of mortality. A value of
p
< 0.05 was accepted as
statistically significant.
Results
This retrospective epidemiological research on IE was conducted
in a regional referral hospital. Evaluation was made of a total
of 139 patients with IE, comprising 59.7% males and 40.3%
females, with a mean age of 55 ± 16 years. The basal clinical
characteristics of the subjects and predisposing conditions for IE
are presented in Tables 1 and 2, respectively.
The primary symptom was fever in 77 (55.4%) patients,
coagulase-negative staphylococci (30.2%) were the most frequent
causative agents, and the mitral valve was the most commonly
affected site (54%) in the study population. The frequency of
IE-related symptoms and the site of endocarditis are listed
in Table 3, and the causative micro-organisms are presented
in Table 4. The median time between hospital admission and
diagnosis was three (five) days.
Transthoracic echocardiography (TTE) displayed a vegetation
or related formation (abscess, fistula, dehiscence) in 64.7%
of the patients, and this rate increased to 99.3% with the use
of transoesophageal echocardiography (TEE). In 44 patients
(31.6%) a vegetation was determined on TEE and not on TTE.
Echocardiographic examinations displayed moderate to severe
mitral regurgitation in 63 patients (45.3%), aortic regurgitation
in 40 (28.7%) and tricuspid regurgitation in 33 patients (23.7%).
The surgical treatment ratio was 65.5% in this study
population. The most common reason for surgery was persistent
infection (28.1%), and the median time between diagnosis and
referral for surgery was seven (18) days. Systemic embolism
(39.6%) was the most frequent complication encountered during
the entire follow-up period in these patients with IE. Other
common complications and reasons for surgery are listed in
Table 5.
In-hospital mortality was seen in 42 patients (30.2%) with
a diagnosis of IE. In logistic regression analyses, chronic renal
disease, congestive heart failure and chronic dialysis were found
to be associated with an increased mortality risk. A statistically
significant correlation was determined between mortality and
high C-reactive protein (CRP) and high creatinine levels. The
association of mortality with selected variables is shown in Table 6.
Table 1. Baseline clinical characteristics of the patients
Variables
Number (%)
Gender, female
56 (40.3)
Hypertension
57 (41)
Diabetes mellitus
46 (33.1)
Ejection fraction < 55%
29 (20.9)
Chronic kidney disease
45 (32.4)
Immunosupression
5 (3.6)
Chronic dialysis
33 (23.7)
Active smoking
11 (7.9)
Pacemaker
10 (7.2)
Central venous catheter
23 (16.5)
Prior history of endocarditis
1 (0.7)
Intravascular drug abuse
1 (0.7)
Table 2. Predisposing risk factors of the patients
Underlying heart disease
Number (%)
Intracardiac prosthetic material
35 (25.2)
Prosthetic mitral valve
22 (15.8)
Prosthetic aortic valve
9 (6.5)
Prosthetic tricuspid valve
1 (0.7)
Valvular ring
2 (1.4)
Left ventricular assist device
1 (0.7)
Rheumatic valvular disease
5 (3.6)
Rheumatic mitral stenosis
3 (2.2)
Rheumatic mitral regurgitation
2 (1.4)
Mitral valve prolapse
4 (2.9)
Bicuspid aortic valve
7 (5)
Atrial or ventricular septal defect
7 (5)
Hypertrophic cardiomyopathy
4 (2.9)
Other
3 (2.1)
History of invasive procedure
Percutaneous angiographic procedure
7 (5)
Catheter insertion
6 (4.3)
Valve replacement
3 (2.2)
Dental procedure
3 (2.2)
Endoscopy
2 (1.4)
Table 3. Clinical presentations and site of
endocarditis in the study population
Clinical presentation
Number (%)
Fever
77 (55.4)
Shortness of breath
11 (7.9)
Weakness
16 (11.5)
Cerebral embolism
10 (7.2)
Back pain
5 (3.6)
Cough
3 (2.2)
Nausea, vomiting
3 (2.2)
Vegetation site
Mitral
75 (54)
Aortic
36 (25.9)
Tricuspid
11 (7.9)
Pacemaker
3 (2.2)
Catheter tip
2 (1.4)
Pulmonary
1 (0.7)
Table 4. Micro-organisms isolated from blood cultures in the study
Micro-organisms
Number (%)
Coagulase-negative staphylococcus
42 (30.2)
Staphylococcus aureus
22 (15.8)
Viridans streptococcus
4 (2.9)
Streptococcus bovis
1 (0.7)
Other streptococci
15 (10.8)
Enterococci
9 (6.5)
Brucella
species
5 (3.6)
Pseudomonas aeruginosa
1 (0.7)
Fungal
1 (0.7)
Culture negative
30 (21.6)