Heart Surgery Animation

Chemical Stress Test

People that are having certain heart problems such as chest pain with exertion may be referred by their physician for a cardiac stress test. In a traditional stress test, a person is connected to various heart monitors and asked to walk or run on a treadmill. The intensity of the treadmill workout is increased until the patient experiences chest tightness, they cannot tolerate the level of exertion, or some other factor that limits their performance. This exercise cardiac stress test is a fairly sensitive way to diagnose ischemic heart disease or diseases in which the heart is not getting the blood that it needs.

While an exercise cardiac stress test is a useful and reproducible diagnostic exam, what if a person is wheelchair-bound, has had an amputation, or cannot exercise sufficiently? In cases where jogging on a treadmill for several minutes is not possible, a chemical stress test may be performed instead. Instead of using exercise to stress the heart, a chemical stress test involves the infusion of a drug that “stresses” the heart artificially.

There are several drugs that can stimulate the heart, but the most common agents used in a pharmacological or chemical stress test are adenosine, dobutamine, and dipyridamole (Persantine). In 2008, an agent called regadenoson (Lexiscan) was approved by the FDA for use in chemical stress tests. Adenosine and regadenoson directly stimulate adenosine receptors. When stimulated, adenosine receptors dilate the coronary arteries and blood flow to the heart increases. Persantine works in a similar manner except that it causes the body’s own adenosine to be released into the bloodstream, which affects the coronary arteries in much the same way as direct infusion of adenosine.

Dobutamine stimulates the same receptors on the heart that would be stimulated by adrenaline. Instead of directly and only causing the blood vessels around the heart (coronaries) to dilate, dobutamine increases heart rate, blood pressure, and heart muscle contraction.

With adenosine chemical stress test protocols, the medication opens all coronary arteries around the heart but diseased arteries do not open as much as healthy arteries. Therefore blood flow greatly increases to the regions of the heart that have healthy coronary arteries but only to a small degree in regions fed by diseased coronaries. This imperfect chemical stress test can be made more sensitive and specific for ischemic heart disease by combining the adenosine chemical stress test with mild to moderate treadmill walking. Thus the chemical stress test is enhanced by adding an exercise stress test component.

Many scientists and physicians believe that dobutamine provides better results as a chemical stress test than the adenosine related compounds; however, adverse reactions occur in fully 75 percent of dobutamine chemical stress test procedures, which severely limits its use. In addition to the several chemical stress test side effects with dobutamine, there are several contraindications to using dobutamine. Even in ideal conditions many people are simply not permitted to receive dobutamine for safety reasons.

While chemical stress tests can provide positive results in some people, especially those with significant coronary artery disease, physicians agree that exercise stress tests are much more sensitive. If your physician refers you for a cardiac stress, you should discuss the advantages and disadvantages of exercise and chemical stress test protocols and discuss whether you are physically able to perform a full exercise stress test.

Epidural & Spinal Anesthesia

Laser liposuction

Laser liposuction is one of the newest procedures for fat removal. It combines a laser with a probe that is similar to a liposuction cannula (without the suction part). While it is catching on in the United States, it is not offered by as many surgical practices as traditional liposuction and may take some searching to find a physician that is skilled in this technique. Laser liposuction offers some potential advantages over regular liposuction procedures and should be considered by anyone who is entertaining the possibility of weight loss surgery.

Laser liposuction is really a misnomer since there is no suction involved in the process. In regular liposuction, a wand is placed under the skin which vibrates at very high frequency to liquefy the fat. That liquefied fat is then suck out with a small vacuum hose and discarded. In laser liposuction, instead of using vibration energy to liquefy the fat, light energy is used to instantly zap the fat cells. A laser, which is an intense, focused collection of light energy, is used to instantly vaporize the cells at which it is aimed. The small blood vessels that are broken and leak blood during regular liposuction are instantly cauterized by the laser during laser liposuction. This means that there is less bleeding and bruising with laser liposuction versus regular liposuction. Proponents of the technology also claim that the laser light works to tighten the surrounding skin suggesting that laser liposuction does not result in baggy, excess skin sometimes present after traditional liposuction.

Another interesting feature of laser liposuction is that it can be performed under local anesthesia rather than general anesthesia. This means that the area to be treated is completely numbed by injecting the area with an anesthetic while the patient is awake during the procedure. Patients can sit upright or stand during the laser liposuction procedure. In certain cases this is highly advantageous. For example, if belly fat is being removed, having the patient stand during the procedure will allow the surgeon to see how gravity layers the fat in the abdominal region. When the patient is standing, the surgeon can target all of the fat areas appropriately.

Laser liposuction may not be for everyone. While it is quite safe, it may not be appropriate for patients with diabetes, liver or kidney problems or blood clotting problems. It is best reserved for areas that do not contain much fat such as the inner thighs, face and neck, chin and other smaller regions. While laser liposuction can be performed on belly fat, it may not remove as much fat as the patient would like. In these cases, traditional liposuction may be more appropriate.

The procedure is relatively brief, lasting 30 to 60 minutes. The recovery is quite quick, also, even compared to regular liposuction. The procedure is performed on an outpatient basis meaning the patient can arrive at and leave the office on the same day. Most people return to work after 24 hours. Do not expect to see results instantly, however, since the full benefit of liposuction may take six to eight weeks to be seen completely.

Laser liposuction is one of the newer fat removal techniques and may offer certain advantages to traditional liposuction for some patients. For larger collections of fat, traditional liposuction may still be the best approach. Talk to your plastic surgeon to find out more about both techniques.