Non-bacterial Thrombotic Endocarditis

*Carmen Busca-Arenzana, Angel Robles-Marhuenda, Luis Ramos-Ruperto and Jorge Alvarez-Troncoso* 

## **Abstract**

Non-bacterial thrombotic endocarditis or also called verrucous endocarditis or Libman-Sacks endocarditis or marantic endocarditis is a rare entity, still unknown physiopathology, which is characterized by the formation of sterile vegetations at the valvular structures. These vegetations of platelet aggregates and fibrin are sterile by definition, so for its definitive diagnosis, it is essential to rule out an infectious endocarditis. It is mainly diagnosed by echocardiography in patients with neoplasms or systemic autoimmune diseases. Its main complication is the formation of multisystemic embolisms, preferably at the brain level, so anticoagulation will be fundamental in the treatment and evolution of non-bacterial thrombotic endocarditis.

**Keywords:** Libman-Sacks endocarditis, marantic endocarditis, non-bacterial thrombotic endocarditis, non-infective endocarditis, verrucous endocarditis

### **1. Introduction**

 Non-bacterial thrombotic endocarditis (NBTE) is a rare entity in which a state of hypercoagulability predisposes to the formation of sterile vegetations in heart valves and secondary systemic embolisms, mainly in the central nervous system. In many occasions, the diagnosis is made postmortem, finding up to 0.2% of the autopsies of the general population [1]. The pathogenesis is unknown, being associated mainly with the existence of neoplastic processes and systemic autoimmune diseases (mainly in systemic lupus erythematosus (SLE) or antiphospholipid syndrome (APS)).

 For the diagnosis it is necessary to demonstrate the presence of valvular vegetations by echocardiography, ruling out the existence of an underlying infection. There is no specific treatment, so it is recommended to control the predisposing disease and the initiation of anticoagulation to avoid the production of systemic embolisms [2].

#### **2. Epidemiology and etiology**

The NBTE is a rare pathology, whose diagnosis occurs generally in autopsies, being present in 0.9–1.2% of them, according to the series [3]. However, it is believed to be an underdiagnosed entity. It is described at any age, although it is more prevalent in patients between 40 and 80 years of age. Children tend to present milder clinical forms, with a lower number of systemic embolisms [4].

#### a.Malignancy


b. Systemic autoimmune diseases

	- ° Giant cell arteritis
	- ° Behçet disease
	- ° Takayasu's arteritis
	- ° Polyangiitis with granulomatosis

c. Hypercoagulability states

	- ° Thrombotic thrombocytopenic purpura
	- ° Catastrophic antiphospholipid syndrome
	- Tuberculosis
	- Uncontrolled HIV
	- Chronic pyelonephritis

e. Others


#### **Table 1.**

*Causes of NBTE.* 

The neoplastic disease, generally advanced, is the main risk factor for the development of NBTE. If compared with the general population, this subgroup has a higher risk of presenting it (1.25 vs. 0.2%, respectively) according to a series of autopsies [5, 6]. The adenocarcinomas (i.e., colon, ovary, lung) are the most

*Non-bacterial Thrombotic Endocarditis DOI: http://dx.doi.org/10.5772/intechopen.84398* 

frequent tumors, observing a greater number of cases in the pancreatic and mucin secretors. Other pathologies that are associated are the SLE and the APS. In the SLE, different observational studies show a prevalence ranging between 6 and 11%, being more frequent among lupus patients with antiphospholipid antibodies [7]. Although exceptionally, NBTE can be a complication of systemic infections such as tuberculosis and HIV, and cases have been described in the context of uremia, adenomyosis, and even giant cell arteritis [8]. It should be said that in the cases mentioned of infectious etiology (i.e., tuberculosis, HIV), the development of NBTE is not determined directly by microorganisms, but by alterations in coagulation induced by the underlying chronic inflammatory process (**Table 1**).
