martes, 11 de noviembre de 2014

Cardiovascular research

Why is cardiovascular research so important?

Cardiovascular diseases constitute disorders of the heart and blood vessels, and include coronary heart disease (heart attacks), cerebrovascular disease (stroke), raised blood pressure (hypertension), peripheral artery disease, rheumatic heart disease, congenital heart disease and heart failure. The major causes of cardiovascular diseases are tobacco use, physical inactivity, an unhealthy diet and harmful use of alcohol
 
According to the World Health Organization, cardiovascular diseases are the number one cause of death globally. An estimated 17.3 million people died of cardiovascular diseases in 2008. Recent advances in the diagnosis and treatment of atherosclerosis and heart failure, two cardiovascular diseases with high prevalence, are explained below.

Atherosclerosis

Atherosclerosis is a disease in which a plaque composed by fatty substances, cholesterol, calcium and fibrin (a clotting material in the blood) builds up in the inner lining of an artery. The plaque may partially or totally block the blood's flow through an artery. Atherosclerosis can lead to serious problems, including heart attack, stroke or even death.

Figure A shows a normal artery with normal blood flow. Figure B shows an artery with plaque buildup.
Taken from the National Heart, Lung and Blood Institute web page 

INNOVATION IN THE DIAGNOSIS: there are novel imaging techniques that are used to evaluate the narrowing and the presence of atheromatous plaques in the coronary arteries. In the following pictures, you can observe hybrid images combining PET and MRI that have been developed to improve the specifity and sensitivity of the diagnosis:



INNOVATION IN THE TREATMENT: Coronary angioplasty, also called percutaneous coronary intervention, is a procedure to relieve blocking or narrowing of the coronary arteries. Angioplasty involves temporarily inserting a tiny balloon to widen the clogged artery and it is often combined with the permanent placement of a wire called stent to help prop the artery and decrease the chance of it narrowing again. In the next video, you can see how the stents are used to treat several coronary heart diseases:


Heart failure

Heart failure, also known as congestive heart failure, occurs when the heart cannot pump enough blood to supply the body's needs for blood and oxygen. Common causes of heart failure include myocardial infarction, atherosclerosis, hypertension or valvular heart diseases, among others. The underlying mechanisms of heart failure can be observed in the following video:


Treatment depends on the severity and cause of heart failure. In a chronic patient with stable condition treatment consists of lifestyle changes (smoking cessation, light exercise and dietary changes) and medications. Depending on the etiology, severe heart failure can be treated with implanted devices (i.e. pacemaker or ventricular assist devices). In patients at the end-stage of heart failure, after using all the alternative therapies, heart transplant is required. During the heart transplant, the patient's own heart is either removed (orthotopic procedure) or, less commonly, left in place to support donor heart (heterotopic procedure). The first human transplant was performed by Christiaan Barnard in 1967 in South Africa. Sadly, the patient, Mr. Louis Washkansky (in the picture with Professor Barnard), died of pneumonia 18 days later after the heart transplant due to a weakened immune system.

INNOVATION IN THE TREATMENT: an artificial heart is a device that replaces the heart to bridge the time to heart transplantation. In 1969, Denton A. Cooley and Domingo Liotta replaced, for the first time, the heart of dying man with an artificial heart; the patient lived for 65 hours. Currently, most commonly used artificial hearts are Cardio-West and AbioCor. The main difference between them is that Cardio-West is connected to an external power source, while AbioCor is completely inserted in the chest and its battery is charged through the skin with a special battery charger.

Taken from the National Heart, Lung and Blood Institute web page.



Stroke
 
A stroke occurs when the blood supply to part of your brain is interrupted or severely reduced, depriving brain tissue of oxygen and food. Stroke is the second leading cause of death and the first cause for adult impairment. A ischemic stroke (left picture) occurs as a result of an obstruction within a blood vessel supplying blood to the brain, while an hemorrhagic stroke (right picture) occurs when a weakened blood vessel ruptures. About 87% of all strokes are ischemic strokes.  

http://www.strokeassociation.org/idc/groups/heart-public/@wcm/@hcm/documents/image/ucm_440283@z_extracted~1/medium.jpghttp://www.strokeassociation.org/idc/groups/heart-public/@wcm/@hcm/documents/image/ucm_440285@z_extracted~1/medium.jpg




New developments in cardiovascular research focus on novel tools for the prevention, diagnosis and treatment of cardiovascular diseases.
  1. Identify the healthy habits that prevent cardiovascular disorders as well as risk factors.
  2. Know the characteristics of the novel vascular imaging techniques and the use of coronary stents used for the diagnosis and treatment, respectively, of atherosclerosis.
  3. Familiarize yourself with the different types of artificial hearts.
  4. Be aware of the possibilities and limitations of the different procedures (orthotopic or heterotopic) and types (allograft or xenograft) of heart transplant.



Stephanie Fae Beauclair, better known as Baby Fae, was born in 1984 with hypoplastic left heart syndrome. Her mother, Teresa Beauclair, contacted with Dr. Leonard Bailey, a handful physician and researcher interested in saving infants born with fatal heart defects. Baby Fae became the first patient of a xenotransplant procedure receiving the heart of a baboon. A xenotransplantation is the transplantation of living cells, tissues or organs from one species to another. The procedure was successful, but Baby Fae died 21 days later of heart failure due to the rejection of the xenotransplant. The story of Baby Fae was documented in the film "Stephanie's Heart: The Story of Baby Fae"; you can see the trailer below:


One year later, Dr. Bailey performed the first infant allograft heart transplantation on Baby Moses, whose actual name is Eddie. An allotransplantation is the transplantation of living cells, tissues or organs from a genetically non-identical donor of the same species. Now 29-year-old Eddie holds the distinction of being the oldest living infant heart transplant recipient.

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