Scorpion Toxin Might Benefit Heart Bypass Patients!

The first impression that we hear about scorpions is that we should stay away from them to avoid being stung because poison delivered by some species of scorpion could be deadly. But a new discovery by scientists on scorpions could be good news for heart disease patients.

A paper published on September 29, 2010 in “Cardiovascular Research”, an International Basic Science Journal of the European Society of Cardiology, revealed that a toxin found in the venom of the Central American bark scorpion (Centruroides margaritatus) could help reduce heart bypass failures.

In a study funded by the British Heart Foundation, the Wellcome Trust and the Medical Research Council, researchers from the University of Leeds found that one of the scorpion’s toxins, margatoxin, is at least 100 times more capable in preventing neointimal hyperplasia than any other known compound.

Being the most common cause of bypass graft failure, neointimal hyperplasia is the blood vessel's response to injury. It triggers the growth of new cells, causing chronic blockage on the inside of the vessel.

When a vein is grafted onto the heart during a bypass procedure, the injury response begins as the vein tries to adapt to the new environment and different circulatory pressures. The growth of new cells does help strengthen the vein, but the internal cell growth restricts blood flow and ultimately causes the graft to fail.

The toxin works by suppressing the activity of a specific potassium ion channel, a pore in the cell membrane that opens and closes in response to electrical signals, and indirectly enhances delivery of an intracellular messenger, the calcium ion.

In fact, there were a number of good blockers of the ion channel available. Several compounds are developed from plants but margatoxin was the most potent.

It is believed that margatoxin would probably not suitable as a drug that could be swallowed, inhaled or injected. However, it could be used as a spray-on treatment to the vein itself once it has been removed and is waiting to be grafted onto the heart.

Why Is There a Reduction in Heart Attack Deaths in United States?

When heart attack victims are admitted into hospitals, the doctors therein might have different alternatives to treat their patients. For example, they could use angioplasty to clear out clogged arteries, perform heart bypass surgery, or prescribe medications to lower the cholesterol levels, reduce clotting and regulate heart beat. As such, the success rate of treating these patients could vary widely among various hospitals.

According to a study that was published on August 18, 2009 in the Journal of the American Medical Association, there has been a noticeable reduction in heart attack deaths over the period between 1995 and 2006 as a result of clearer United States guidelines on how to treat elderly heart attack patients.

The researchers from the Yale University School of Medicine in Connecticut found a reduction of 3 percent in the number of patients who died within a month of having a heart attack after the introduction of clearer standards on treatments by Medicare.

Medicare is a social insurance program administrated by the United States government to provide health insurance coverage to people who are of 65 years old and above or who meet other special criteria.

In 1990, the American College of Cardiology and the American Heart Association published joint guidelines on which care was suitable and when. 2 years later, Medicare followed the guidelines.

The researchers studied the records of 2.7 million patients discharged from 4,000 hospitals after having heart attack between 1995 and 2006, and found that among Medicare beneficiaries, there was 1 additional patient survive at 30 days for every 33 patients admitted in 2006 compared with 1995.

The 30-day mortality rate decreased from 18.9 percent in 1995 to 16.1 percent in 2006, and in-hospital mortality decreased from 14.6 percent to 10.1 percent,

Meanwhile, they also discovered that a lot less variation in death rates among the hospitals. Such finding might support the argument that healthcare reform efforts should include more standardized guidelines on patients’ care.

The cause of the reduction has yet to be determined with certainty. Nevertheless, the finding of this study might have already reflected one thing: individuals and organizations dedicated to improving health care during the period begin to see some positive and encouraging results.

Back in 1995, 24 percent or more of heart attack patients died within a month after being treated at 39 hospitals.

Is Ventricular Reconstruction Effective for Heart Failure Patients?

Heart failure is a condition in which the heart is unable to supply sufficient blood flow to meet the body’s needs, and it often occurs after tissue is damaged by a heart attack. Generally, a person can develop heart failure because of myocardial infarction and other forms of ischemic heart disease, hypertension (high blood pressure), valvular heart disease and cardiomyopathy. About 5 million people in the United States are affected by heart failure.

When the heart fails, it will try to compensate for the damage by getting larger, but in the meantime, it will also pump much less efficiently. Ventricular reconstruction is an operation that is designed to help patients with heart failure. It involves folding the scarred portion of a damaged heart in on itself to get it to beat more effectively.

However, in a so-called STICH trial, doctors from Duke University Medical Center in North Carolina found that such operation provides no real benefit to most patients. Basing on work carried out at 96 medical centers in 23 countries, the findings were presented on March 29, 2009 at a meeting of the American College of Cardiology in Orlando and published in the New England Journal of Medicine.

During the STICH trial, doctors compared what happened to the 1,000 volunteers, who all got heart bypass operations, and half of them also got ventricular reconstruction. The results showed that ventricular reconstruction neither lowered the death rate or the risk of going back to the hospital nor improved the quality of life after 4 years.

No doubt, many patients have a lot fewer symptoms with the operation, but some patients could have the similar improvement with good medical treatment involving drugs. In fact, a patient will save an average of US$14,595 in the hospital costs, and the patient will spend one half hour less in the operating room.

Nevertheless, the operation is seldom carried out in the United States. In fact, only 3,000 to 5,000 such operations have been done worldwide in the last 10 years.

Can The Robot Do The Heart Bypass Surgery?

In conventional heart bypass surgery, a patient will have to go through his or her most painful experience because his or her breastbone has to be sawn open. In addition, there will be a long zipper scar on the chest.

However, Smith (not his real name), who had a heart bypass in July 2007, does not have the long scar. Instead, there are only two 2cm long and a 5cm long scars. This is because his surgeons at the National Heart Centre (NHC) in Singapore used a robot to perform minimally invasive 'keyhole' surgery. His doctor also operated while his heart was beating. A retired teacher with an age of 80 years old, Smith went home after 5 days in hospital. He felt so lucky and claimed that there was not any pain after the operation.

The robot used in the surgery is called the da Vinci surgical system. It allows heart surgeons in Singapore to perform heart bypass, repair heart valves and remove chest tumors in a minimally invasive way. In fact, the robot has also been used for prostate surgery in Singapore since 2003.

As the robotic heart procedures are still new, doctors use them only on patients whose conditions are not complicated and who agree to the procedures.

Smith also puzzled when his doctor sought his agreement on the robotic procedure. He finally agreed only after the doctor reassured him that he actually controls the robot and that he had operated on 4 patients successfully.

The aim of the robotic procedure is bring less pain, less blood loss and faster recovery for patients. Most patients in United States are discharged 2 to 3 days after the operation, as compared to conventional bypass patients of 6 or 7 days in hospital. Nevertheless, patients in Singapore are normally discharged after 4 to 6 days, as the doctors want to be careful.

Conventional bypass surgery requires surgeons to open up the chest to reach the heart. Patients are then connected to a heart-lung machine that takes over the functions of those organs, and the heart is stopped. A vein, removed earlier from the patient’s thigh or chest, is attached to the heart arteries to create a bypass to re-channel blood away from blockages.

In a robotic procedure, it is not necessary for the surgeon to cut open the chest because the robot's arms can enter the patient’s body through small cuts and do the job within the chest. The main surgeon just needs to sit at a console to control the robotic arms to get the job done.

The robotic procedures usually cost about 10 to 20 percent more than that of the conventional heart bypass surgery. But if it can do a better job for the patients, why not?