**2. Materials and method**

A prospective study was performed on 236 consecutive patients diagnosed with IE according to Duke criteria [7] in our institute. The study protocol was approved by the institute management and Ethics Committee. All patients included in the trial gave written, informed consent. The study was in accordance with the Declaration of Helsinki regarding the human rights. The follow-up period was extended 3 years after randomization or until cardiac surgery whatever occurred the first and included clinical and echocardiographic examination for each visit.

The study protocol was completed with demographic data, the clinical status of the patient, VEG echographic parameters, EE occurrence, the antibiotic treatment efficacity and duration. The main echographic parameters measured on the VEG were: the maximum length (L), the maximum (tmax) and minimum (tmin) thickness, the narrowest diameter, the presence of the neck and its dimensions (lneck) and the mobility defined as the angle of displacement of long axis of vegetation throughout the cardiac cycle (**Figure 1**). The data base was done using Visual Fox Pro program.

The main prediction variables used were: NYHA class for heart failure, Duke criteria used for IE diagnosis (fever, new regurgitation murmur, blood cultures, inflammatory tests, leukocytosis, anemia), type of IE (on native valve or prosthetic) and the type of the surgical intervention. The main outcome variables were: the presence and the type of EE, death occurrence and its causes.

The characteristics of the studied group were as follows:

• 58% male, the mean age was 47.8 ± 6 years;

are associated with a higher mortality rate. The incidence of embolic complications is higher in IE located on aortic and mitral valve and in IE due to *Staphylococcus aureus*, Candida species, HACEK and Abiotrophia organisms. The highest rate of embolic events is seen within the first 2–4 weeks of antimicrobial therapy [5], and it drops dramatically during the first 2 weeks of successful antibiotic therapy, from 13 to <1.2 embolic events per 1000 patientdays. Prediction of individual patient risk for embolization has proven extremely difficult. Echocardiography is the main investigation used in a lot of studies to identify a high-risk subset of patients with IE who might benefit from early surgery in order to avoid embolization. Higher embolic rates revealed by several studies using transthoracic echocardiography (TTE) and TEE were seen with the increase of the VEG dimensions [6]. Vegetation mobility has not been shown to be an independent risk factor for embolic events, probably because it is strongly correlated with VEG size [5]. In other studies, the embolic complications were by the infecting organism and the number of VEG, the number of valves involved and VEG

That is why the first objective of our study was to identify the echographic parameters which were associated with the presence of an EE in patients with IE. Using these variables we tried to define the echographic parameters which can help in defining the high-risk groups for EE in IE patients and to evaluate the real value of the TEE for the EE prediction in these patients. Finally, we examined the relationship between the incidence of an EE occurrence during the antibiotic treatment and the type of antibiotherapy and the echographic predictors for a new

A prospective study was performed on 236 consecutive patients diagnosed with IE according to Duke criteria [7] in our institute. The study protocol was approved by the institute management and Ethics Committee. All patients included in the trial gave written, informed consent. The study was in accordance with the Declaration of Helsinki regarding the human rights. The follow-up period was extended 3 years after randomization or until cardiac surgery whatever occurred the first and included clinical and echocardiographic examination for

The study protocol was completed with demographic data, the clinical status of the patient, VEG echographic parameters, EE occurrence, the antibiotic treatment efficacity and duration. The main echographic parameters measured on the VEG were: the maximum length (L), the maximum (tmax) and minimum (tmin) thickness, the narrowest diameter, the presence of the neck and its dimensions (lneck) and the mobility defined as the angle of displacement of long axis of vegetation throughout the cardiac cycle (**Figure 1**). The data base was done using

The main prediction variables used were: NYHA class for heart failure, Duke criteria used for IE diagnosis (fever, new regurgitation murmur, blood cultures, inflammatory tests,

characteristics.

72 Advanced Concepts in Endocarditis

each visit.

Visual Fox Pro program.

EE during antibiotherapy.

**2. Materials and method**


**Figure 1.** The echographic parameters measured on the vegetations.

The data collected represented the fields of a database in the Visual Fox Pro program. Data were processed using the Excel, Epi Info, Systat and SPSS programs for measurement of the power association between the prediction and outcome variables using the following tests:

• a relative risk = 1 included the patients subgroups classified as with no effect of the pres-

Prediction of Embolic Events in Infective Endocarditis Using Echocardiography

http://dx.doi.org/10.5772/intechopen.76845

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• a relative risk < 1 was considered favorable; for these patients, the occurrence of an EE was

The patients were divided into two groups depending on the occurrence of the EE: group

Depending on the VEG site, most of the patients (49.34%) had VEG on mitral valve, 42.79% on aortic valve, 4% both on mitral and aortic valve and 3% had right heart endocarditis (**Figure 2**).

1. The incidence of the EE in patients with IE (diagnosed on Duke criteria) was 51.27% (121 patients). There were no significant differences for the occurrence of EE according to sex, age, fever presence, anemia, vegetation site or the presence of a significant regurgitation

2. The univariate analysis has shown a significant correlation between the EE presence and IE with staphylococcus, IE of the right heart, the length and mobility of vegetation. The only independent predictors for the EE revealed by the multivariate regression analysis were: the maximum length > 15 mm (RR = 4.92, p = 0.0001) and the increased mobility of the VEG with the maximal angle > 60.7 degree ± 12 (RR= 8.2, p = 0.003) (**Figure 4**). The univariate regression analysis has shown a significant correlation between the presence of an EE and the following parameters:

The multivariate regression analysis showed that the only echographic independent predic-

• the increased mobility of the vegetation—estimated as "the maximal angle of displacement of long axis of the vegetation throughout the cardiac cycle" more than 60.70 ± 12 (RR = 8.2,

The maximum length of the VEG more than 15 mm increased the embolic risk by 4.92 times and its value between 10 mm and 15 mm by 1.84 times. Values less than 10 mm of the maximum length of the VEG turned out to be protective for EE, the associated RR being 0.92.

decreased due to the presence of the group characteristic by the RR value.

A—121 patients without an EE and group B—115 patients with an EE.

ence of group characteristic;

**3. Results**

murmur (**Figure 3**).

tors of the EE were:

p = 0.003).

• IE with Staphylococcus (R<sup>2</sup> = 0.71, p < 0.0001);

• the maximum length of the vegetation (R<sup>2</sup> = 0.921, p < 0.01);

• the maximum length of the vegetation > 15 mm (RR = 4.92, p = 0.0001);

• the mobility of the vegetation (R<sup>2</sup> = 0.48, p < 0.001).

• right heart IE (R<sup>2</sup> = 0.43, p < 0.0001);


The main methods of statistical correlation used in the study were the following:


No sample size assumptions have been made. No confirmatory statistical hypothesis was prespecified, but a detailed analysis plan was defined before the database was locked. Continuous data are expressed as mean ± SD. Discrete variables are expressed as counts (percentages).

According to the exposure level to the risk factors, data were grouped on the presence of an EE and the type of the treatment (surgical intervention or medical therapy). For each exposure level, there were introduced the number of patients with an EE (cases) and the number of patients without an EE (controls). The confounders were controlled by stratification.

Data interpretation was performed taking into account the following hypothesis:

• a relative risk >1 was considered unfavorable; for these patients, the occurrence of an EE was increased due to the presence of the group characteristic by the RR value;

**Figure 2.** Patient distribution by vegetations site (229 patients).


The patients were divided into two groups depending on the occurrence of the EE: group A—121 patients without an EE and group B—115 patients with an EE.

Depending on the VEG site, most of the patients (49.34%) had VEG on mitral valve, 42.79% on aortic valve, 4% both on mitral and aortic valve and 3% had right heart endocarditis (**Figure 2**).
