Despite our nation’s best effort to treat all forms of cardiovascular disease aggressively, we seem to be losing the struggle.
- According to the National Heart, Lung & Blood Institute, 30% of all Americans are hypertensive, and more than 65% of people diagnosed with this condition—do not get adequate treatment and continue to have uncontrolled pressure long after diagnosis.
- 50% of patients experiencing a heart attack had normal brachial blood pressure and/or normal cholesterol levels prior to the event (Sachdeva A, et al; Am Heart J. 2009;157(1):111–117.e2).
- 75% of people suffering strokes had normal brachial blood pressures in the months prior to the events.
- Nearly 75% of individuals with diabetes will die from cardiovascular disease complications.
So, here is our question: Are we measuring the correct pressure? There is an ever-increasing body of evidence that says NO!
Central aortic systolic pressure (CASP) has been found to be more predictive of heart disease than brachial pressure, yet until recently this valuable early detection tool had limited clinical utility because the technology was costly and unwieldy.
That is about to change, as new and much less expensive technology makes CASP a feasible option in primary care settings. A recent edition to the CPT coding system-- the 0311T code for non invasive arterial studies—should help as well!
A More Accurate Picture
There are a variety of systems used to measure CASP, but the basic principle involves assessing systolic pressure at the root of the aorta, near the heart (read, Digital Pulse Wave Analysis Offers Non-Invasive Early Heart Risk Assessment )
A number of studies have shown that CASP provides a more accurate assessment of risk than conventional brachial measurements.
For example, the Conduit Artery Function Evaluation (CAFE)—a trial comparing amlodipine (calcium channel blocker) versus atenolol (beta blocker) in more than 2,000 hypertensive peope—showed distinct differences between the two drugs with regard to their effects on aortic pressure, despite similar effects on brachial pressure. The authors concluded that measuring pressure at the arm tends to underestimate the effect of calcium channel blockade, while overestimating the effect of beta blockade (Williams B, et al. Circulation. 2006;113(9):1213-25).
Data from the Strong Heart Study indicate that central pressure better represents the load imposed on the coronary and cerebral arteries, giving a more clear picture of the likelihood of vascular damage and a more accurate prognosis. Based on measurements from more than 3500 patients, the authors found that central pressure measurements bore stronger relationships than brachial measurements to carotid artery hypertrophy (intimal-medial thickness and vascular mass), extent of atherosclerosis (plaque score), and incident cardiovascular events (Roman MJ, et al. Hypertension. 2007; 50(1): 197-203).
Lower Costs, Wider Use
CASP is typically lower than the brachial pressure in most people. When we are young, below 40 years of age, the difference between CASP and the brachial pressure can be significant (up to 30 mmHg difference). However, as we age, the aorta gets stiffer and less compliant. As a result, CASP increases and comes much closer to the brachial pressure. In patients with hypertension, the CASP can be abnormally high at any age, showing “pre-mature” stiffening of the aorta.
Putting CASP and brachial pressure head to head, CASP may be the more important measurement to take. It is now possible to measure CASP and arterial stiffening non-invasively, quickly, accurately, and affordably.
Until recently, the cost and complexity of measuring systems kept CASP monitoring in the research lab and in large hospitals. Up until 4 years ago, there were only three companies marketing CASP systems, and the equipment ran between $12,000 to $15,000. Today, there are 12 available systems, and costs have come down to between $5,000 and $9,000 for systems appropriate to medical practice.
It is expected to become a required test in renal departments of hospitals and dialysis centers within the next two years. Further decreases in start up costs plus the fact that it is now a billable and reimbursable service will no doubt move CASP into primary care.
The big news is that simple home monitoring systems are now available at around $600. Currently, home-based systems are only available to patients by prescription, meaning that doctors can make it available to patients in whom the daily home measures might provide important insight into the level of CVD risk.
For practitioners who do not want to rely on or are not able to bill insurance, the lower cost of the technology allows for easy integration into direct-pay practice. We have found that once patients understand the value of the information that a test like CASP provides, many are willing to pay for it.
One of the greatest values of CASP is that it can measure the effect of lifestyle modifications, drug therapies and or nutritional supplementation protocols. It reflects changes in vascular function, thus allowing you to prove to patients that something actually works at the heart, where it matters most.
The majority of cardiovascular experts now agree that most heart disease is preventable and reversible. Yet, it remains the number one killer of Americans. If one can take a more predictive measurement, non- invasively and at significant lower cost than before, it certainly makes good sense to do so!
Peter Bottemanne has had a lifelong interest in fitness and nutrition, a passion which has led him to a management role at Amerging Medical (www.amergingmedical.com), a company focused on disseminating smart technology for the prevention of cardiovascular disease. Amerging Medical’s mission is to provide new affordable advanced technologies, in an ecosystem of health and wellness partners, for the purpose of prevention.