| The technique involves the use of the EECP Device
to inflate and deflate a series of compression cuffs wrapped around the
patient's calves, lower thighs, and upper thighs. Inflation and deflation
of the cuffs are modulated by events in the cardiac cycle via computer-interpreted
ECG signals. During diastole, the cuffs inflate sequentially from the calves
proximally, resulting in augmented diastolic central aortic pressure and
increased coronary perfusion pressure. Compression of the vascular bed
of the legs also increases venous return and cardiac output. Rapid and
simultaneous decompression of the cuffs at the onset of systole permits
systolic unloading and decreased cardiac workload. In the treatment regimen
established to date, patients are treated with EECP 1hour a day for a total
of 35 hours. At the start of treatment, external compression is progressively
increased, as needed, to raise diastolic pressures gradually.
Finger plethysmography is used to monitor correct timings.
The concept of counterpulsation is based on a favourable response of the
left ventricle to reduce are can be reduced. However, effective perfusion
pressure must be maintained to meet the metabolic needs of the body. Under
circumstance of decreased systolic pressure, diastolic pressure must be
increased in order to maintain effective perfusion. This requires a system
that can be synchronized and phased with cardiac activity.
Studies of the haemodynamic effects of counterpulsation
have revealed that several factors give this modality the potential to
assist patients with low cardiac output syndromes.
• Counterpulsation increases the stroke volume per
unit work and; therefore, the efficiency of the left ventricle. Either
the left ventricular pressure and PTM (pressure time per minute) are reduced,
or the cardiac output is increased, or both.
• Diastolic perfusion pressure and the ratio of the
mean diastolic pressure to the mean systolic pressure are increased.
• Coronary flow increases preferentially with the distolic
pressure since coronary vascular resistance is minimal during cardiac diastole.
• The coronary collateral flow to ischemic regions
of the myocardium is increased.
• Modification of the pulse pressure distribution in
the aorta favours increased mean arterial pressure and; therefore, flow
to the vital organs.
In studies to date, therapy with EECP has been well
tolerated by all patients enrolled. No patient withdrew after enrollment,
and there have been no reported complications. Patients should not experience
pain during treatment with EECP. Discomfort from the pulsatile movement
and pressure on legs and buttocks may be eliminated or minimized through
use of suitable protective clothing, such as tights or bicycle pants worn
during treatment.
Conclusion
Based on observed response in clinical trials, therapy
with EECP can offer symptomatic and clinical relief in patients with angina
pectoris, including reduced need for antianginal medications, reduced frequency
and intensity of chest pain and increased exercise tolerance as well as
immediate and sustained improvement in myocardial perfusion of ischemic
areas. As a result of symptomatic and clinical improvements, patients have
reported an improved sense of well-being and overall improvement in quality
of life. Treatment with EECP offers potential clinical benefits to patients
who generally have little else than medica1 therapy as a recourse. Studies
have shown that treatment with EECP improves angina symptoms and perfusion
of ischemic regions of the myocardium (assessed through nucleography) for
up to three years following initial treatment. |
