Epidemiology, outcomes and prognosis of infective endocarditis in Northern Morocco – BMC Infectious Diseases

Epidemiology

Our study shows that IE predominantly affects younger individuals with an average age of 46 years. A similar observation is made in Cameroon, as mentioned in the study by Jérôme Boombhi et al. [3] , with an average age of 44 years, and in Algeria, the study by Bennata et al. [4] reports an average age of 40.5. However, the series by Toyoda et al. reports an average age of 62 [5] . In France, as mentioned previously, infective endocarditis is increasingly affecting elderly individuals, with the average age rising from 58 to 62 years between 1991 and 2008.

In our study, infective endocarditis is equally common in men and women. In the series by Toyoda et al., 59% of endocarditis cases were in women [5] . However, a male predominance was noted in the series by Fedeli et al. (62%) [6].

Recent dental care (7.5%) and acute rheumatic fever (10%) are the main risk factors for infective endocarditis according to our study. In the study by Boombhi et al., rheumatic valvular disease represents the main cause of infective endocarditis followed by degenerative valvular heart disease [3] . Similarly, in the study by Bennata et al., rheumatic heart disease account for 70% of cases [4]. Additionally, 33% of patients have a history of rheumatic heart disease according to Blanchard et al. [7].

In contrast, in the Toyoda series conducted in New York, recent valve surgery and the presence of intracardiac material are major risk factors for infective endocarditis [5].

Infective endocarditis on native valves is more common than on prosthetic valves according to our study (77% vs. 23%). This aligns with most series.

Diagnosis

Interrogation and clinical aspects

Interrogation must be thorough to detect risk factors for infectious endocarditis.

Infectious endocarditis can be acute, rapidly progressive, subacute, or even chronic. The average treatment time in our study is 25 days. In a study conducted in Rabat by S. Harrak, the average time required for diagnosis is 77 days [8].

Infectious endocarditis can be diagnosed based on symptoms such as fever, joint pain, general malaise (anorexia, asthenia, weight loss), or cardiac signs such as dyspnoea, chest pain, and palpitations. In our study, fever is present in 90% of cases, while in the series by Duval, 86% of patients are febrile [9] . Boombhi’s study shows that all patients have fever [3].

In our series, general malaise is found in 87.5% of patients. Splenomegaly associated with general malaise was present in 11% of cases in the study by Montassier conducted in France [10] . Symptoms found in our patients include dyspnoea in 65% of cases, cough in 23.8% of cases, and chest pain in 8.8% of cases.

Heart failure is found in 51.2% of cases, in Fedeli’s study HF is found in 13% [6] , in Duval’s study HF is found in 33.8% [9] , and represents 26% in Benatta’s study [4] in a Tunisian study HF presents 41.5% [10, 11] .

In our study series, cardiac auscultation revealed that 77.5% of patients had a murmur. In 73.8% of patients, the rhythm is regular.

Extra cardiac manifestations

Vascular phenomena are found in 2.5% of cases. Neurological signs in 10% of cases. A lone purpura is noted in 6.3% of cases. Purpura was associated with Osler’s nodes in 1.3% of cases. Ocular phenomena represent 1.3% of cases. Splenomegaly in 12.5% of cases. In Montassier’s study, Osler’s nodes are found in 5% of cases, Janeway lesions in 5% of cases, conjunctival purpura in 5% of cases, Roth’s spots in 5% of cases, and neurological manifestations in 5–20% of cases [10].

Echocardiography

In addition to blood cultures, echocardiography is the second major criterion for the diagnosis of IE. It plays a crucial role in for diagnosis, prognosis, and treatment monitoring.

Vegetation is present in 76.3% of cases in our study, while in the study by S. Harrak [8] , it is present in 95% of cases. It predominantly occurs at the mitral level in our study, with a percentage of 39.3%, but according to the study by S. Harrak [8] , vegetation predominates at the aortic level with a percentage of 46%, followed by the mitral level with a percentage of 28%.

Myocardial abscess is present in 11.3% of cases in our study, according to S. Harrak [8], it is present in 25% of cases.

As for other destructive lesions 10% of patients had chordal rupture and 12.5% had perforation, while in the study by S. Harrak [8] , 60% of patients had perforation and 43% had chordal rupture. Mycotic aneurysm is present in 2.5% of patients. Prosthesis detachment is reported in 3.8% of cases, in the Harrak study [8] , it was reported in one patient.

Echocardiography assesses the impact of underlying valvopathies by the following data in our study: S. Harrak found that LV dysfunction is reported in 32%, LV dilation in 64%, LA dilation in 70%, intra-LA thrombus in 6%, ascending aorta dilation in 25%, pulmonary hypertension (HTAP) in 88%, IVC dilation and decreased compliance in 36% [8].

Microbiology

Positivity of blood cultures

Haemocultures were positive in 41,3% of cases in our study. However, in industrialized countries, the proportion of negative blood cultures ranges from 5 to 15%, while the proportion of positive blood cultures is approximately 85% [2, 3] . This issue arises in almost all underdeveloped countries.

Microbiology

In our work, the predominant pathogen responsible for infectious endocarditis is Staphylococcus, accounting for 65.6% of cases. This is consistent with the series by Fedeli [6] , with a rate of 42%, and that of Nappi [12] , with a staphylococcal rate of 36.3%. However, in the study by Boombhi in Cameroon, streptococcus predominates as the cause of IE (20%), followed by Staphylococcus (10%) [3] . Streptococcus is in the second line in 22% of cases, with Lactococcus lactis in 22% of cases, and finally, Enterococcus in 11% of cases. The blood cultures in our study did not identify other pathogens that are responsible for IE, as mentioned in the 2023 ESC guidelines [1] . No rare IE-related pathogens were identified in our study. These pathogens include bacteria such as Klebsiella spp., Corynebacterium, Campylobacter, Yersinia, Nocardia, Pasteurella, Listeria and even rarer ones such as Serratia marcescens, Aeromonas Salmonicida [13].

Treatment aspects

Antibiotics

Since the majority of blood cultures are negative (59%), antibiotic therapy has mostly remained probabilistic, based on patient history, medical records, clinical signs, whether IE is present on a native valve or a prosthesis (early or late). echocardiographic findings, and sensitivity profile to common pathogens.

Modification of antibiotics were made based on the antibiogram data when blood culture is positive.

The empiric antibiotic protocols used in the data from the work of S. Harrak are mostly Ampicillin or 3rd generation cephalosporins + gentamicin for native valve IE, and mostly Vancomycin + gentamicin for prosthetic valve IE.

Surgery

Fifteen percent of patients underwent early surgery. Among these patients, 41.7% of indications were embolic, 33% were for hemodynamic indications, and 25% were for infectious indications. In the series by S. Harrak, 7% of patients underwent early surgery, and the main indication was mostly hemodynamic [8].

Prognosis

Mortality

According to studies, in-hospital mortality is approximately 15 to 25%, 6-month mortality is 30%, and 5-year mortality is around 40%. These data hardly change over time. This is probably due to the epidemiological developments of IE, with more frequent nosocomial-origin infections affecting older patients with multiple comorbidities [2, 3] . The mortality rate in our series is 12.5%.

Prognostic factors

In our study, the prognostic factors found in patients who did not improve or died are shown in Table 4.

Summary chart

Following the results of our study, we summarize the characteristics of our population in Table 5.