2026, Number 1
Clinical features, echocardiographic findings and surgical aspects related to mortality in complicated endocarditis
Full text
10.35366/122889
Language: English
References: 17
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ABSTRACT
Infective Endocarditis is a serious public health problem with high morbidity and mortality, and a considerable prevalence in our setting. International guidelines for the diagnosis and treatment of endocarditis consider clinical, laboratory, and imaging criteria to define this entity and establish recommendations for its management. Global mortality is estimated around 20%; however, there is no information available on the epidemiology or prognosis in Mexico. An important finding among patients at our centre is the incidence of cases with local complications. Naturally, as anatomical complexity increases, surgery becomes more challenging, so local complications are expected to directly influence the risk of perioperative death. The purpose of this study was to identify risk factors associated with echocardiographic complications in patients diagnosed with Infective Endocarditis (IE) at tertiary level public hospital, as well as to evaluate their postoperative outcome. This information could contribute to a better understanding of IE and facilitate more timely treatment. Over a five-year period, 60 patients were included, with an incidence of local complications of 73.3%. No variables were significantly associated with the development of local complications. However, type 2 diabetes (p = 0.03), heart failure (p = 0.01), and prosthetic valves (p = 0.03) were risk factors associated with mortality. Regarding clinical scenario, uncontrolled sepsis (p = 0.02), septic shock (p = 0.01) and multiple organ failure (p = 0.001) at the time of IE diagnosis and after surgery, had higher mortality (p = 0.02).ABBREVIATIONS:
- CHD = Congenital Heart Disease
- CIE = Complicated Infective Endocarditis
- IE = Infective Endocarditis
- IVDU = Intravenous Drug Users
- TOE = Transesophageal Echocardiography
- TTE = Transthoracic Echocardiography
INTRODUCTION
Infective Endocarditis (IE) is a life-threatening disease characterized by inflammation of the valves, endocardium, and vascular intima caused by pathogenic microorganisms. It represents a major public health problem, with an estimated incidence of 13.8 cases per 100,000 people per year in 2019. To date, the increasing population at risk and the emergence of new clinical scenarios have raised these numbers.1,2
In response to this more challenging landscape, recommendations for the diagnosis and treatment of IE have been updated, starting with the identification of susceptible patients with high and intermediate risk features2,3 such as previous IE, surgically implanted prosthetic valves or other materials including filters, grafts, closure devices and ventricular assist devices, and patients with Congenital Heart Disease (CHD). Likewise for right-sided IE, different vulnerable groups can be distinguished based on patients' characteristics, including Intravenous Drug Users (IVDU); IE in patients with pacemakers, implantable cardiac defibrillators or central venous catheters and IE in patients with right-heart congenital abnormalities.4
Transthoracic (TTE) and Transesophageal (TOE) echocardiography play a key role in the evaluation and prognostic assessment of patients with IE. Echocardiography is the imaging modality of choice for diagnosing IE (as it constitutes a major Duke criterion), and is essential for monitoring disease progression (particularly for the detection of complications) and guiding treatment. Findings must be interpreted with caution, always considering the patient's clinical presentation. Notably, a negative echocardiographic examination does not rule out IE, and repeating TTE and TOE may be necessary in certain situations.4
The echocardiographic diagnosis of IE is primarily based on vegetations finding, assessment of the degree of valvular and perivalvular damage, evaluation of resulting hemodynamic abnormalities, and identification of associated complications.5
Vegetations remain the hallmark lesion of IE. They typically appear as oscillating or non-mobile masses attached to valvular structures and may be located anywhere on the valvular apparatus, prosthetic intracardiac materials, or mural endocardium. Identification of vegetations can be challenging in the presence of pre-existing valvular lesions (such as mitral valve prolapse, degenerative calcified leaflets, or calcified mitral annulus), prosthetic materials, or small vegetation size. Embolization before echocardiographic examination is another potential cause of a false-negative result.6,7
Perivalvular extension of infection leads to the development of abscesses, pseudoaneurysms, fistulae and new prosthetic dehiscence (Figure 1).6,7
Abscesses typically present as thickened, heterogeneous perivalvular areas with echodense or echolucent appearances, without detectable color Doppler flow within. In contrast, pseudoaneurysms appear as pulsatile, perivalvular echo-free spaces containing color Doppler flow.4 Fistula formation may occur as a complication of abscesses or pseudoaneurysms; however, in some cases, fistulous tracts develop as a direct consequence of infection due to tissue necrosis and rupture without prior abscess formation. Echocardiographically, they are documented when a color Doppler flow jet is observed communicating two adjacent cavities, and they may be misinterpreted as perforated valve aneurysms.8,9
Leaflet perforation is practically pathognomonic of leaflet infection, while prosthetic valve dehiscence may present clinically with hemolytic anemia. IE should also be suspected in cases of new perivalvular regurgitation, even in the absence of visible vegetations or other periannular complications.4
The in-hospital prognosis of IE is influenced by four main factors: patient characteristics, the causative microorganism, and the presence or absence of cardiac and non-cardiac complications.10,11 Within this context, the most important factors affecting clinical outcomes include congestive heart failure, valvular dysfunction, and thromboembolic events.12-14
Furthermore, perivalvular extension of IE is the most common cause of uncontrolled infection and is associated with poor prognosis and a high likelihood of requiring surgery.4
It stands to reason that the more complex the injury, the more difficult the surgery may be. Additionally, such complexity implies longer cardiopulmonary bypass times, which in turn exacerbates the inflammatory response, promote greater bleeding, and increase the risk of coagulopathy and associated metabolic disorders. Therefore, local complications are expected to directly influence perioperative mortality risk.
Despite advances in medical therapies and surgical techniques, the morbidity and mortality of IE remain high, with up to one in five deaths occurring during the initial hospitalization.15,16 Given its poor prognosis and high mortality, early diagnosis and timely intervention are of paramount clinical importance.5
MATERIAL AND METHODS
This was a retrospective cohort study conducted at a tertiary-level public hospital, covering a five-year period from January 1, 2019, to December 31, 2023.
The study included adult patients (≥ 18 years), both men and women, who had been hospitalized at our institution with a confirmed or suspected diagnosis of Infective Endocarditis. All information was obtained exclusively from existing medical records and surgical reports. No direct patient contact or intervention was performed. The data were used to compare echocardiographic descriptions with intraoperative findings and to verify the presence of local complications.
Because this study involved only the review of anonymized clinical records, no informed consent was required.
All patients included in the study had previously undergone transthoracic echocardiography, and in selected cases, transesophageal echocardiography, performed during their hospitalization using a Philips 7C model 01800 253 0446. Surgical indications in each case had been determined according to the 2015 and 2023 ESC guidelines for the diagnosis and treatment of Infective Endocarditis.
Information regarding intraoperative findings, hemodynamic conditions, and outcomes was extracted from surgical and postoperative records. For patients with fatal outcomes, intraoperative events were reviewed as documented in the clinical files. Postoperative courses and complications were compared between the two groups based on the information available in the medical records.
Statistical analyses were performed using SPSS version 25. Qualitative variables are expressed as frequencies and percentages, while quantitative variables with non-normal distributions are described as medians and interquartile ranges. Group comparisons were carried out using the χ2 test for categorical variables and the Mann-Whitney U test for continuous variables. A 95% confidence level was used, and p-values < 0.05 were considered statistically significant.
RESULTS
A sample of 60 patients was collected, ensuring at least one case of IE each was reported per month. The demographic and clinical features of our sample are summarized in Table 1.
There were nearly three times as many male cases, and in 80% of these, men were also the most affected by local complications. Notably, the largest age subgroup among patients with CIE was that of young patients under 30 years of age (34.9%), although this group represented only 35% of non-survivors. Complicated cases were three times more common in patients with prosthetic valves.
Information on comorbidities and known predisposing factors was recorded (Figure 2). The most prevalent chronic conditions were hypertension, chronic kidney disease, heart failure, and type 2 diabetes. Other immunosuppressive conditions such as HIV infection, cancer, and autoimmune diseases, were also present but albeit in only 15% of patients.
As outlined in the 2023 ESC guidelines, several cardiac and non-cardiac risk factors may increase susceptibility to Infective Endocarditis. In a targeted search for such risk factors, the most frequently observed were recent hospitalization (within one month prior to diagnosis), the presence of central venous access, and ongoing infections with gastrointestinal, respiratory, genitourinary, or soft tissue foci. Although CHD was present in 28.3% of all patients, it had not been previously diagnosed in 94% of these cases and was only discovered upon the diagnosis of endocarditis (Table 2).
Interestingly, none of these factors appeared to be associated with an increased risk of local complications. However, with regard to mortality in global population, diabetes (p = 0.03), heart failure (p = 0.01), and prosthetic valves (p = 0.03) were statistically significant predictors. In fact, patients with prosthetic valve Infective Endocarditis had five-fold higher odds of in-hospital mortality compared to those with native valve endocarditis (OR 5.0, 95%CI 1.24-20.18; p = 0.017).
We also recorded the time from the onset of initial symptoms to the formal diagnosis of IE. Longer progression periods were observed in complicated cases, with a maximum duration of 270 days; however, no statistically significant differences were found when compared to patients without local complications (Figure 3).
Clinical presentation at diagnosis was also analyzed. In both groups, uncontrolled sepsis and systemic embolism were the most frequent presentations. Among patient with locally complicated IE, acute heart failure, septic shock, and multi-organ failure were also prominent diagnostic indicators (Table 1).
Regarding systemic embolism, affected sites included the lungs, spleen, kidneys, central nervous system, eyes, musculoskeletal system, pancreas, and mesenteric circulation (Figure 4). Stroke was the cause of hospitalization in 11.6% of the overall cohort.
Other cardiac complications were documented exclusively in patients with local complications, including third-degree atrioventricular block, acute coronary syndrome, cardiogenic shock, and even cardiac tamponade.
Most cases met 1 major and 3 minor Duke criteria for diagnosis, particularly embolic phenomena, persistent fever and less frequently autoimmunity manifesting Roth spots and glomerulonephritis in a couple of cases. Interestingly, in the uncomplicated subgroup, three times as many cases were diagnosed using both major criteria.
The microbiological profile of patients with Infective Endocarditis is displayed in Table 3 and Figure 5, as well as in Tables 4 and 5. Microbiological isolation was obtained from blood cultures; tissue cultures were not routinely performed due to logistical and resource limitations, and therefore were unavailable in a substantial number of cases. While the latest 2017-2023 report from the PUCRA network of hospitals in Mexico reported E. coli as the most frequently isolated microorganism,17 this bacterium appeared in only 6% of the total cases, while Staphylococcus aureus had a prevalence of 26%.
The empirical treatment until identification of the etiological agent in each case was based on the epidemiological profile of our centre and the management algorithm established by the Infectious Diseases Service (Table 6).
Echocardiographic findings of Infective Endocarditis are summarized in Table 7. The aortic valve was the most commonly affected. In 26.6% of cases, two or more valves were involved, sometimes simultaneously on both left and right sides in the presence of structural defects. Other sites of involvement included the right atrium, right ventricular outflow tract, Eustachian valve, and moderator band. Vegetation size exceeded 20 mm in 20% of cases. Valvular regurgitation –rather than obstruction– was the predominant dysfunction, ranging from moderate to severe in 86.6% of patients. Echocardiographic signs of local complications extended to the interatrial and interventricular septum, aortic root, mitral-aortic continuity, sinuses of Valsalva, and even the pulmonary artery trunk.
Overall post-surgical mortality was 53.3%, with 31.3% in the uncomplicated group and 61.4% in the CIE group. Among patients who underwent surgery (Figure 6), postoperative outcomes were categorized and compared. Among non-survivors, emergency surgery was required in 32.1% of cases, at least two valves were replaced in 32.1%, additional procedures beyond valve replacement were performed in 42.9%, intraoperative defibrillation was needed in 42.9%, and 57.1% experienced hemodynamic instability (Table 8). These findings reflect a highly adverse clinical scenario before and during surgery, which severely reduced the chances of survival.
No significant association was found between CIE and postoperative complications aside from mortality. Multi-organ failure as a postoperative complication was associated with an 83.3% mortality rate (p = 0.02). Cardiogenic shock and superinfection were more common among fatal cases, though these did not reach statistical significance (Figure 7).
Finally variables significantly associated with mortality in univariate analysis and clinically relevant baseline characteristics were included in a multivariable logistic regression model. The analysis showed that diabetes remained independently associated with in-hospital mortality (adjusted OR 4.4, 95%CI 1.0-18.9; p = 0.049), whereas prosthetic valve endocarditis was no longer significantly associated with mortality after adjustment.
DISCUSSION
Although our analysis did not allow us to identify specific demographic or clinical characteristics that clearly predisposed patients to the development of intracardiac complications, we did observe a direct association between the presence of such complications and a higher risk of perioperative mortality. This finding underscores the clinical relevance of early recognition of locally Complicated Infective Endocarditis (CIE), particularly through echocardiographic evaluation, as these complications significantly affect prognosis.
With regard to comorbidities, type 2 diabetes and heart failure were more frequently observed among deceased patients. However, it is important to emphasize that these conditions were not independently associated with the development of local complications. Rather, the majority of fatal cases corresponded to patients who already presented echocardiographic evidence of periannular extension or other structural damage at the time of diagnosis. This may suggest that comorbidities exert their impact indirectly, primarily by worsening systemic decompensation once complications emerge, rather than functioning as direct primary risk factors for CIE itself.
Although prosthetic valve Infective Endocarditis was associated with a five-fold increase in mortality, the relatively small prosthetic subgroup (n = 15) may have led to instability in the effect estimate. The wide confidence interval suggests limited precision, and larger studies are needed to confirm this association.
An additional aspect that deserves attention is the frequent delay in diagnosis observed in our cohort. In many cases, patients were initially managed under the suspicion of alternative conditions due to the clinical presentation dominated by systemic embolism (e.g., stroke, splenic or renal infarction). This often postponed the recognition of IE as the underlying cause, thereby extending the time from symptom onset to definitive diagnosis. Such diagnostic delays may have contributed to the advanced stage at which local complications were identified, further worsening prognosis and limiting surgical outcomes.12
Several limitations must be acknowledged. First, the retrospective design of this study carries an inherent risk of information bias, as data collection relied on medical records and echocardiographic reports. Second, the relatively small sample size limited the statistical power to detect additional associations between predisposing factors and outcomes. Third, the absence of advanced imaging modalities such as cardiac CT or PET/CT, which are increasingly used to improve diagnostic accuracy in Infective Endocarditis, may have led to an underestimation of the true prevalence of local complications.7
Despite these limitations, our findings highlight the prognostic significance of echocardiographic complications in IE and reinforce the importance of multidisciplinary management.16 Early diagnosis and timely surgical intervention remain crucial strategies to improve outcomes, particularly in resource-limited settings such as large public hospitals, where delays in referral and treatment are frequent.
CONCLUSIONS
In this cohort, patients who developed uncontrolled sepsis, septic shock, or multiple organ failure at the time of IE diagnosis had significantly higher mortality. No additional risk factors demonstrated statistical significance as predictors of local complications. However, patients with Complicated Infective Endocarditis (CIE) presented a 3.4-fold higher risk of death compared with those without local complications.
Despite the absence of statistically significant predictors for the development of CIE, mortality was notably influenced by pre-existing comorbidities such as diabetes, heart failure, and prosthetic valves. Moreover, echocardiographic findings confirmed the central role of local complications in adverse outcomes, especially when associated with severe valvular dysfunction, systemic embolism, or conduction disorders.
These findings reinforce the importance of early recognition of systemic and cardiac complications at the time of IE diagnosis. The high perioperative mortality observed in CIE highlights the need for timely diagnosis, multidisciplinary management, and rapid surgical decision-making to improve patient prognosis.
ACKNOWLEDGEMENTS
We appreciate the collaboration from other members of the Cardiology staff specially Dr. Jhasiel Vladimir Villa Alcaraz and Dr. Pamela Milijaed Muñoz Reyes; members of the Echocardiographic Department and Cardiothoracic Surgery Department.
REFERENCES
Habib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta JP, Del Zotti F et al. 2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by: European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Nuclear Medicine (EANM). Eur Heart J. 2015; 36 (44): 3075-3128.
Universidad Nacional Autónoma de México. Plan Universitario de Control de la Resistencia Antimicrobiana (PUCRA). Resistencia antimicrobiana en México 2017-2023: reporte de los hospitales de la Red PUCRA: resistencia antimicrobiana y consumo de antibióticos. Ciudad de México: Universidad Nacional Autónoma de México; 2024.
AFFILIATIONS
1 MD Cardiology Physician. Cardiology Department, General Hospital of Mexico "Dr. Eduardo Liceaga". Mexico.
ORCID:
2 0000-0002-2765-8078
3 0000-0003-1335-9672
Declaration of confidentiality and patients consent: we declare that the entire information from patient\'s records is confidential and had been used with strictly academic purposes. However, data has been de-identified.
Clinical trial registration and approval number: does not apply.
Funding: this research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Declaration of interests: the authors have no conflicts of interest to disclose.
CORRESPONDENCE
Jessica Mariel Bazo-Medina. E-mail: mariel.mb@outlook.comReceived: 09/17/2025. Accepted: 03/12/2026