What Is CASP?

Back Ground

These days doctors’ offices and hospitals are filled with advanced, high tech medical Equipment. However, one device that has changed very little over the past century is the blood pressure cuff, which evaluates a person’s systolic (upper number) and diastolic (lower number) blood pressures. In fact, the current device used in most clinical settings is very similar to the first blood pressure cuff created in the late 19th century. And while this monitor does a decent job of determining a person’s general cardiovascular outlook when used consistently, the area of blood pressure monitoring has long been due for improvement and modernization.

In the past, the only way a doctor could get the most accurate reading, the CASP or Central Arterial Systolic Pressure, was through cardiac catheterization, which involves inserting a catheter with a sensor into the femoral artery in the thigh and advancing it to the aortic valve at the base of the heart. This was considered the gold standard of blood pressure measurements, but needless to say, this wasn’t a desirable way to obtain a blood pressure reading. It’s both risky, as it could dislodge arterial buildup and cause a stroke or heart attack, as well as costly (catheterization can cost between $15,000 and $20,000).

The high cost and risk resulted in catheterization only being used when there was a real reason to do so. In other words, only when heart disease was already suspected. Catheterization would never be used as a preventative measurement of heart disease.

And yet , heart disease remained then, as it does today , the number 1 killer.

So, science set out to find noninvasive methods of measuring the central blood pressure.

The first generation of such devices came out some 20 years ago. The Portapress cost 40k and the Sphygmocor 32k. The high cost of these devices limited the use to only clinical settings in hospitals. The significance of that is that 90% of the treatment of cardio vascular disease is conducted by the general practitioners. So, those that could do the most to educate the patient about the prevention of heart disease did not have access to this technology.

The second generation of these noninvasive devices came out about 10 years ago. The Bpro runs around 12k. The reduced cost now allows general practitioners to start using the device, resulting in a body of evidence about the reduction of cardio vascular risk.

The third generation has recently come on the market. Both the Caspro and Cardioscope have become available at such reduced prices 8,5k and 6.5k respectively, that widespread use can now be envisioned. Not only can hospitals and clinics use these devices, but also medical practitioners in the life sciences or wellness sector can.

Over time these devices have also gained accuracy as a result of measuring simultaneously with catheterization. The devices are all clinically accurate and meet the SP10 threshold.

So, why has it been long suspected that central blood pressure is more predictive of heart disease than brachial blood pressure? For it only stands to reason that a measurement closer to the heart and brain must be more predictive than the measurement further away in the arm. Because the heart pumps directly to the brain and other vital organs, it is here where high pressure can do the most of its damage.

Two studies have come to some exciting conclusions:

the Cafe study has shown that in 2 patients  both suffering from hypertension, but one with an elevated Casp and the other with a normal Casp, that certain blood pressure reducing medication, can have an adverse effect on CASP. So, simply reducing the blood pressure without regard to the Casp, could increase the underlying risk of heart disease instead of reducing it.

The Strong Heart study has been able to quantify the increase in risk of cardio vascular events and stroke, as a result of an increase in the Casp. So by treating the increase in Casp, one is effectively reducing the risk of cardio vascular events.

The now available devices offer a range of information that should relate to the use of the practitioner. The more diagnostic the use, the higher range is required. The more observational, the lower range can be used.

On the high end the device reads the traditional blood pressure and the casp. It also analyses the pulse wave form over a 24 hour period, determines its amplitude and velocity, as well as radial augmentation index. All of these are added indices, that can help a doctor assess a patients overall arterial health. The doctor can provide a treatment based upon the outcome of the measurement. The efficacy of any prescribed medication can be time tested by reviewing a follow up measurement.

The mid-range device is not capable of 24 hour monitoring, but can establish the BP, CASP, RAI, MAP, PP and pulse wave analysis. The interpretation of the data requires training.

The low end use is for observational purposes only. There is very little training required, as the device is very simple and intuitive. Don’t belittle the effect this device can have!  Since heart is disease is known to be the silent killer, it can strike without warning. Many of its victims show no signs or symptoms. So many people have no idea that they are suffering from the underlying causes of heart disease. They won’t think to measure their arterial health. This device can have substantial impact on the lives of those previously undiagnosed.

As such this device can be primarily used as a preventative tool. When the results, fall outside the scope of the practitioners capacity, the practitioners should recommend elevating the result to a general practitioners for diagnosis.

What is CASP?

Central Aortic Systolic Pressure (CASP), it has been shown in many studies to be the strongest independent risk factors for stroke, heart attacks and the likelihood of survival after such an event.   This is the blood pressure at the root of the aorta or the largest artery in the body, as the blood is being pumped out of the heart. CASP has been shown to be an important factor in the relation to strokes and cardiovascular events, more so than the brachial pressure or the pressure at the arm commonly.

This is the blood pressure at the root of the aorta or the largest artery in the body, as the blood is being pumped out of the heart. This pressure is called Central Aortic Systolic Pressure or CASP. CASP has been shown to be an important factor in the relation to strokes and cardiovascular events, more so than the brachial pressure, or the pressure at the arm commonly.

CASP is different and usually lower than the brachial pressure in normal people. When we are young, below 40 years old, the difference between CASP and the brachial pressure can be significant (up to 30 mmHg). However, as we age, the aorta gets stiffer and the compliance reduces. As a result, the CASP increases and comes much closer to the brachial pressure. In patients with high blood pressure, the CASP can be abnormally high for his age, showing “pre-mature” stiffening of the aorta.

It has also been shown that certain class of drugs used in the treatment of high blood pressure can also have an adverse effect on the CASP, increasing it instead of reducing, as shown in the CAFÉ study. Therefore it is important to show that the treatment a patient is taking actually result in lowering the CASP and not the reverse. By reducing the CASP of the patient, we are reducing the risks of stroke and heart events.