What is IVUS?

Intravascular Ultrasound (or IVUS) allows us to see a coronary artery from the inside-out. This unique point-of-view picture, generated in real time, yields information that goes beyond what is possible with routine imaging methods, such as coronary angiography, performed in the cath lab, or even non-invasive Multislice CT scans.

This cross-section view can aid in stent sizing, and in confirmation that the stent has been placed optimally, is fully expanded and hugging the vessel wall. A growing number of cardiologists feel that the new information yielded by IVUS can make a significant difference in how a patient is treated, and can provide for more accurate stent placement, reducing complications and the incidence of stent thrombosis.

How Does IVUS Work?

IVUS uses ULTRASOUND: the same technology as the ultrasound imaging used echocardiography and many other medical exams. Very high frequency sound waves, called ultrasound, are emitted by a transducer. These ultrasound waves, which are beyond the range of human hearing, bounce off the various types of tissue structures in the body and the echo of these waves is then converted into a picture.

In the case of Intravascular Ultrasound, the transducers have been miniaturized to less than four hundredths of an inch and placed on the tip of a catheter. This catheter can be slipped into the coronary arteries over the same guide wire that is used to position angioplasty balloons or stents. It becomes, in effect, a tiny camera that gives us a cross-sectional view of the artery, a view that shows distinct circular layers, using shades of gray or colors.

When is IVUS Done?

Intravascular ultrasound is done in the catheterization laboratory in conjunction with angiography. Some cardiologists use it occasionally to assist in the selection and sizing of stents and balloons. Others use it routinely, to confirm accurate stent placement and optimal stent deployment.

How Can IVUS Make Stenting More Accurate?

With the accurate measurements of both the true diameter of the artery and the diameter of the open lumen channel provided by IVUS, the guesswork is taken out of choosing the correct size balloon and stent. Using only angiography, a cardiologist may underestimate the size of a diseased artery.

IVUS can also measure the length of the diseased area, so the precise length of the stent needed can be determined ahead of time, reducing the need for overlapping stents which are known to increase the risk of thrombosis.

Once the stent has been implanted, IVUS can clearly show the stent struts in relation to the arterial wall and plaque. If the stent has been undersized or if there is any area that needs "touching up", a larger balloon can be directed to it and expanded to fit the stent optimally.

Cholesterol is both our friend and foe - at normal levels, it is an essential substance for the body's normal functioning, but if levels in the blood get too high, it becomes a silent danger that puts us at risk of a heart attack.

What is cholesterol?

Cholesterol is a fatty, waxy substance that is mainly produced by our liver. What we eat can contribute to high blood cholesterol, so it is important to follow a heart-healthy eating pattern. Eating foods with more unsaturated fats in place of saturated or trans fats and avoiding refined carbohydrate foods can help improve cholesterol levels.
Saturated and trans fats are found in higher amounts in animal products like butter, cheese, processed or fatty meats (like ham, salami, sausage); as well as in deep fried foods, pies, pastries, biscuits and cakes.
Apart from the effect of certain foods, high blood cholesterol levels can also be due to a genetic (inherited) disorder. Whatever the cause of your high cholesterol, it is important to lower your levels through lifestyle changes and/or medication.

What does cholesterol do?

Cholesterol is important as it helps our bodies function properly. However, if there is too much cholesterol in your blood, it will build up in your artery walls, causing narrowing of the arteries. This increases your risk of developing heart disease or having a stroke.

Cholesterol and other fats are called lipids. There are different types of lipids within our body. Each has a different function:

• High Density Lipoprotein cholesterol (HDL) is often called the ‘good’ cholesterol because it helps remove cholesterol from the artery walls. This reduces your risk of heart disease.
  
• Low-Density Lipoprotein cholesterol (LDL) is often called the ‘bad’ cholesterol because it deposits cholesterol into the artery walls. This increases your risk of heart disease.
• Triglycerides are the most common form of fat in our body. They are a storage form of energy for the body. High triglyceride levels are associated with many diseases, including heart disease and stroke.

Cholesterol is found in every cell of the body and has important natural functions. It is manufactured by the body but can also be taken in from food. It is waxy and fat-like in appearance. Cholesterol is oil-based and so does not mix with the blood, which is water-based. It is therefore carried around the body in the blood by lipoproteins.
The parcels of cholesterol are carried by two types of lipoprotein:

• Low-density lipoprotein (LDL - cholesterol carried by this type is known as 'bad' cholesterol).
  
• High-density lipoprotein (HDL - cholesterol carried by this type is known as 'good' cholesterol).

Cholesterol has four main functions, without which we could not live. It:

• Contributes to the structure of cell walls
  
• Makes up digestive bile acids in the intestine
• Allows the body to produce vitamin D
• Enables the body to make certain hormones

Recent developments on cholesterol from MNT news

Dementia health also affected by cholesterol levels. The balance of LDL and HDL cholesterol levels is important not just for heart health but for brain health too, according to a December 2013 study. The research, published in JAMA Neurology, found that control of cholesterol reduced the brain plaques linked to Alzheimer's disease.
High cholesterol linked to infertility - prospective parents with high cholesterol levels could be in for a long wait to become pregnant, a new study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism states.
Study links high LDL cholesterol to aortic valve disease - a study published in JAMAclaims to have found evidence to support a causal association between high levels of "bad" cholesterol and aortic valve stenosis - a form of aortic valve disease in which the valve is narrowed, restricting blood flow from the heart.

Cholesterol diet

The support charity for people with high cholesterol, HEART UK, has identified "six super foods" that actively lower cholesterol levels:

• Soya foods (15g a day) - soya milk, soya desserts, soya meat alternatives, soya nuts, edamame beans and tofu
  
• Nuts - a handful a day
• Oats and barley - providing the soluble fiber beta glucan
• Plant sterols/stanols - found in a wide range of foods
• Fruits and vegetables
• Foods rich in unsaturated fats - for example, canola and vegetable oils.

Lists foods that are bad for cholesterol levels:

• Butter
  
• Ghee
• Hard margarines
• Lard
• Fatty and processed meat
• Dairy fats

What causes high cholesterol?

High cholesterol or hypercholesterolemia is also known as hyperlipidemia and dyslipidemia. It is a major risk factor for coronary heart disease, a cause of heart attacks, and reducing blood lipid levels lowers the cardiovascular risk.

High levels of LDL lead to a build-up of cholesterol in the arteries, whereas HDL carries cholesterol to the liver for removal from the body. A build-up of cholesterol forms part of the process that narrows arteries, called atherosclerosis, in which plaques form and cause restriction of blood flow.

Two types of cause lead to high cholesterol levels - modifiable and non-modifiable risk factors. The major two risk factors are highly modifiable - something can be done to change them:

• Diet
  
• Exercise and weight

Limiting intake of fat in the diet helps manage cholesterol levels, limiting foods, in particular, that contain:

• Cholesterol (from animal foods, such as egg yolks, meat and cheese)
  
• Saturated fat (found in some meats, dairy products, chocolate, baked goods, and deep-fried and processed foods)
• Trans fat (found in some fried and processed foods)

Being overweight or obese can lead to higher blood LDL levels so exercise can help manage this risk factor .

The primary causes of hyperlipidemia are genetic - very high LDL levels are found in the inherited condition familial hypercholesterolemia. Other genetic conditions passed down from parents are: familial combined hyperlipidemia, familial dysbetalipoproteinemia and familial hypertriglyceridemia

Abnormal cholesterol levels may also be secondary to the following:

• Diabetes
  
• Liver or kidney disease
• Polycystic ovary syndrome
• Pregnancy and other conditions that increase levels of female hormones
• Underactive thyroid gland.
• Drugs that increase LDL cholesterol and decrease HDL cholesterol (progestins, anabolic steroids and corticosteroids).

Fast facts on cholesterol

Here are some key facts about cholesterol. Find more detail and supporting information in the article.

• Cholesterol is an essential substance that is produced by the body but is also available from foods.
  
• The greatest risk factors for high cholesterol are modifiable lifestyle choices - diet and exercise.
• High cholesterol levels can be inherited with the genetic condition, familial hypercholesterolemia.
• Having high cholesterol does not produce any symptoms.
• Cholesterol levels should be blood-tested once every five years.
• First-line ways to reduce cholesterol involve lifestyle changes.
• If lifestyle changes are unsuccessful or cholesterol levels are very high, lipid-lowering drugs such as statins may be prescribed.
• High cholesterol levels are an important contributor in the calculation of an individual's risk of having a heart attack within the next ten years.

Signs and symptoms of high cholesterol

Having high cholesterol levels, while a risk factor for other conditions, does not itself present any signs or symptoms.2,7 Unless routinely screened through regular blood testing, high cholesterol levels will go unnoticed and could present a silent threat of heart attack or stroke.

Cholesterol tests and diagnosis

High cholesterol can only be diagnosed by blood testing. Doctors' guidelines state that everyone over the age of 20 years should have their cholesterol levels checked once every five years.
The cholesterol test is done after a period of fasting - no food, drink or pills for 9 to 12 hours - to enable an accurate reading of LDL cholesterol from the blood test.The screening also gives information about total cholesterol, HDL cholesterol and triglyceride levels.

In cases where there is severe calcifications, or in cases where calcifications are so severe that only a wire, not a balloon, can cross the site of stenosis, High speed Rotablation Angioplasty (Rotablation Atherectomy) is the treatment of choice.

Rotablation can make treatment possible, or at least easier, For rotablation to take place, access to the coronary artery has to be established using standard procedures . A special guide wire, which is required for the drill, is advanced past the site of stenosis. After a trial run outside the body, the guide wire is then used to advance the drill head to the site of stenosis. The drill, which is powered by compressed air, is advanced through the site of stenosis at a speed of 140,000-160,000 rpm. The process of drilling through plaque and calcified deposits inside the site of stenosis generates tiny fragments of debris, which can easily pass through the blood vessels and are absorbed by the body.

Once the drill head has been retracted, the site is widened using balloon angioplasty as per standard PTCA procedures. This step is usually followed by the implantation of drug-eluting stents , which ensure that treatment results remain satisfactory over the long term. In many cases, high pressure balloons are used to ensure that the stents are fully expanded.

By using a drill that removes calcified deposits, the operator can ensure that the stent does not get caught in calcified deposits, and is not prevented from being advanced into the target zone.

Rotablation is not suitable in cases where balloon angioplasty has resulted in tears to the vessel walls, where there is evidence of blood clots, or where there is a high degree of vessel tortuosity.

• Coronary Angiography and Angioplasty (PTCA) from Femoral (Groin) and Radial (Wrist) Route
  
• Rotablation Angioplasty
• Fractional Flow Reserve (FFR) guided Angioplasty
• IVUS Guided Angioplasty
• MRI compatible dual chamber pacemaker implantation
• Implantation of Combo device Cardiac Resynchronization Therapy Heart device, (CRT-D ) for cases of Chronic Congestive Heart Failure
• ASD VSD PDA Mitral Valve repairs through groin without cutting open the chest wall