Monday, February 12, 2007 Dumaguing: Shockwaves do not break your heart By Dr. Vic Dumaguing To Your Health
SHOCKWAVES have been used for lithotripsy (breaking-up of kidney stones) for more than 25 years. Recently, doctors started to use low energy shockwaves for treating angina pectoris due to ischaemic conditions of the heart.
Atherosclerosis of the coronary arteries is the cause of low blood supply of the heart muscle, leading to angina pectoris and myocardial infarction. This is one of the most frequent causes of death in the western world. Standard treatment is cardiac medication, percutaneous coronary angioplasty and bypass surgery.
Some patients, however, cannot be relieved from chest pain for technical or medical reasons. One example would be when a small vessel is not accessible to a revascularisation procedure or the general condition of the patient makes the risk of an intervention too high. In addition, a lot of these patients re-experience symptoms after some time, mainly in an ageing population with a high percentage of co-morbidity.
Therefore, a non-invasive treatment is highly desirable.
Cardiac extracorporeal Shock Wave Therapy (CSWT) has been shown to increase capillary density and regional myocardial blood flow in sham controlled animal experiments. In addition, non-enzymatic and enzymatic nitric oxide (NO) production and the up-regulation of vascular endothelial growth factor (VEGF) have been described.
These two substances are among the most potent stimulators of the formation of new capillary blood vessels (angiogenesis). Therefore, we hypothesized that CSWT in patients with chronic stable angina pectoris would relieve symptoms and ameliorate the ischaemic threshold.
In a placebo-controlled study, 15 patients (mean age 68 ± 8 years, 14 male) with chronic stable angina pectoris and evidence of inducible myocardial ischaemia during MIBI-SPECT imaging were randomized into a treatment (n=8) and a placebo arm (n=7). Medication was kept unchanged.
The treatment, which consisted of nine sessions of about 30 minutes each for three months, is painless, does not require anaesthesia or sedation and can be done on an out-patient basis. The focus of the shockwaves is targeted on the ischaemic area of the heart muscle under continuous ultrasound imaging control (Storz Medical Modulith SLC).
In the treatment group, the ischaemic threshold, assessed during a cardiopulmonary exercise stress test, was increased, whereas in the placebo arm there was no change. The item "physical functioning" of the quality of life questionnaire SF-36 showed amelioration in the treatment group, whereas no change occurred in the placebo group. Arrhythmias, rise in troponin or other complications, were not observed during or after the treatment.
In addition to the University Hospital "Inselspital", Bern, Switzerland, the same treatment has been conducted in other clinics in Germany, Italy, Austria and Japan. These groups confirm previous results reporting an increase of myocardial perfusion in SPECT imaging, reduction in the Canadian Cardiovascular Society angina class and a reduction in anti-anginal medication. Similarly, hospital admission of the patients after CSWT for cardiac reasons was reduced by a factor of four compared with the period before the treatment.
This preliminary data suggest that CSWT improves symptoms and delays the ischaemic threshold in patients with chronic stable angina pectoris. The fact that a safe, cheap and painless treatment may produce such a benefit is of major importance.
