Vegetation Characteristics and Risk of Embolization

Introduction:

Blood vessels connect all the organs to supply them with proper nutrients and oxygen. There are conditions in which certain blood vessels are blocked due to the deposition of a certain mass. This mass can be natural or synthetic. The natural mass can be made of fatty deposits, different cells, and bacteria forming clumps called vegetation. The size, shape, location, mobility, and other characteristics can impose risk in embolization (transportation of the vegetation). These vegetations can be identified using diagnostic methods, and the treatment is decided. Various management strategies are available to combat the possible risks and prevent the death of patients to a greater extent as the condition is lethal.

What Is Vegetation?

Vegetation, in the case of embolization, is referred to the mass blocking the blood vessel. Vegetation is made up of germs and certain cell structures. The bacteria (germs) clump with other cells forming a mass that can be transported to other parts through blood vessels or block the same blood vessel.

What Are Vegetation Characteristics?

The characteristics of vegetation include:

• Size of the vegetation.

• Length of the vegetation.

• Location of the vegetation.

• Shape of the vegetation.

• Mobility of the vegetation.

• Number of vegetation.

All the characteristics mentioned above show an impact on the risk of embolization.

What Is the Risk of Embolization?

• Any block in the blood vessel may not have originated in the same vessel. Instead, it might have formed in another blood vessel and transported to other blood vessels until its path is narrowed and further transportation is impossible. Such a process is called embolization.

• Fragmentation of vegetation can increase the risk of embolism.

• Depending on the vegetation characteristics, the risk of embolization in patients with infective endocarditis (heart disease) is most probable.

What Is Infective Endocarditis?

• Infective endocarditis is a life-threatening condition in which bacteria enter the bloodstream and get deposited in the heart walls, valves of the heart, or blood vessels.

• Embolic events are most likely to occur in infective endocarditis.

What Are the Symptoms of Infective Endocarditis Associated With Embolization?

• Inability to move on one side of the body.

• Decreased sense of touch.

• Weakness.

• Fever.

• Increased sweating.

• Vomiting.

• Muscle and joint pain.

• Chills.

• Headaches.

• Breathlessness.

• Swollen limbs.

How Are Vegetation Characteristics and Risks of Embolization Related?

Dominant vegetation characteristics usually tend to show an increased risk of embolization.

• Size of Vegetation - A larger vegetation size of more than 10 mm is associated with an increased risk of embolization.

• Location of Vegetation -

1. Mitral Valve - One of the heart's four valves prevents blood backflow. It separates the lower left part of the heart and the upper left part of the heart.

2. Aortic Valve - Separates the left lower part of the heart and the main connecting artery (blood vessel) aorta.

The presence of vegetation on the mitral valve poses more risk of embolization than that present on the aortic valve.

• The Shape of Vegetation -

1. Globular Shape of Vegetation - Shape nearly in the form of a sphere or globe.

2. Non-globular Shape of Vegetation - Irregular in shape.Increased risk of embolization is seen due to the globular shape of vegetation than the non-globular shape.

Increased risk of embolization is seen due to the globular shape of vegetation than the non-globular shape.

• Length of the Vegetation - Vegetation of more than 10 mm shows an increased risk of embolization than less than 10 mm.

• Mobility of Vegetation -

1. Mobile Vegetation - Mobile vegetation is usually transported along with the blood flow until it can no longer travel due to the smaller vessel size. Therefore, larger vegetation can also show fragmentation into smaller mobile parts.

2. Fixed or Immobile Vegetation - Vegetation is formed due to the accumulation of certain compounds and bacteria that adhere to the walls of the organs and do not tend to move.

Mobile vegetation shows an increased risk than fixed vegetation.

• Number of Vegetation - Higher the number of vegetation, the higher the tendency of the blood vessels to get blocked and more risk of embolization.

How Can Vegetation Characteristics Be Identified?

The following are the diagnostic methods to detect vegetation:

• Echocardiography- It is a diagnostic test that uses sound waves to visualize the moving heart, thereby depicting the presence of any blocks or vegetation. It is mainly used as a diagnostic tool for pulmonary embolism (blockage in a blood vessel supplying the lungs).

• Ultrasound - Floating vegetation in the heart, partially attached vegetation to the walls of organs, can be detected using ultrasound.

• MRI (Magnetic Resonance Imaging) - It is used in patients whose diagnosis was not made possible through ultrasound.

• CT (Computed Tomography) - CT scan and angiography can determine any blockages in the blood vessel supplying the lungs.

• PET (Positron Emission Tomography) - The efficiency of PET scan results shows improved diagnostic results.

• Real-Time Three-Dimensional Transesophageal Echocardiography (RT3DTEE) - A recent advancement of two-dimensional echo is used to assess prosthetic valve blockages.

• CRP (Serum C Reactive Protein) - CRP is an important inflammatory marker. Elevated levels of CRP show the presence of risk of embolism.

• Mean Platelet Volume - Increased volume denotes an increased risk of embolic events.

Several other factors in the blood and their changes can predict the risk of embolism.

What Are the Complications Associated With Embolization?

• Local blood vessel inflammation (inflammation of a part in the blood vessel in which blockage is present).

• Malfunctioning of valves in a blood vessel (blood vessel insufficiency).

• Pulmonary embolism (blockage in a blood vessel supplying lungs).

• Mycotic aneurysm (infection of the vessel wall).

• Septic emboli (blockage due to infected blood clot).

• Aneurysmal dilations of a blood vessel (bulging of a weakened area of a blood vessel).

• Previous embolism (already present blocks).

What Is the Treatment to Prevent the Risk of Embolization?

Treatment modalities vary depending on the characteristics of the vegetation.

• Antimicrobial therapy.

• Duration of antibiotic therapy for two to six weeks or prolonged therapy as prescribed.

• Early surgery soon after initiating antibiotic therapy without any delay depending on the clinical condition.

Conclusion:

The characteristics of the disease-causing organism determine the severity of the disease. Likewise, vegetation characteristics causing blockage of blood vessels determine the risk of embolization. Hence, the earliest diagnosis of the vegetation (blocks) can limit embolization risks.