Staging of Hypertension and Total Cardiovascular Risk Assessment: Related but Not the Same—Challenge for the Hypertension Specialist

If you need more airline pilots, you don’t try to make up for it by hiring more flight attendants—George E. Burch, MD

Staging of a disease process (eg, hypertension) is an assessment of the extent to which the disease has advanced at a particular time, that is, it is a snapshot of the pathophysiologic process. On the other hand, total cardiovascular risk assessment is an attempt to predict the future likelihood of the occurrence of a cardiovascular event (eg, myocardial infarction, stroke, sudden death). Of course, staging of hypertension and cardiovascular risk assessment are related, but they are clearly not identical.

Staging of Hypertension

One of the unfortunate byproducts of defining hypertension in the past by arbitrary levels of blood pressure was the staging of the disease using similar blood pressure criteria. The staging of hypertension utilizing blood pressure levels began with the first of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC) reports. ¹ The American Society of Hypertension (ASH) Writing Group, on the other hand, defined the disease of hypertension without blood pressure cutoffs and therefore staged the disease without specific blood pressure numbers. ² This approach permitted the assessment of the progression of the disease by looking for evidence of cardiovascular and target organ damage. Progression included such parameters as microalbuminuria or evidence of left ventricular hypertrophy. The occurrence of a major cardiovascular event clearly placed the progression of the disease in a more advanced stage. Thus, individuals with the same levels of blood pressure might have different stages of hypertension.

Cardiovascular Risk Assessment

Assessment of total (global) cardiovascular risk, achieved by summation of all major risk factors, has been advocated to identify high‐risk patients, motivate patients to adhere to risk‐reduction therapies, and modify the intensity of risk reduction. ³ , ⁴ This approach included the silo approaches proposed by the JNC of the National High Blood Pressure Education Program, Adult Treatment Panel report of the National Cholesterol Education Program ⁵ and the American Diabetes Association. ⁶ Thus, the concept is that total cardiovascular risk should be the concern, rather than concentrating only on the individual components (eg, hypertension, dyslipidemia, diabetes mellitus, age, smoking). The importance of recognizing total (global) cardiovascular risk is that the components interact in a way that is multiplicative rather than simply additive.

It has been suggested that cardiovascular risk determinations begin at age 20  and that total (global) risk assessment be performed at age 40  unless circumstances indicate the need for an earlier date. Given the great importance of this assessment, as well as hypertension staging, it is time to ponder implementation.

Metrics for Treatment Success Differ for Staging and Cardiovascular Risk

The goal of antihypertensive therapy (nonpharmacologic and pharmacologic) is to halt progression of the disease and to reverse the pathologic process. For example, if a patient has left ventricular hypertrophy, regression of the hypertrophy should be documented (by electrocardiography, echocardiography, etc) or a reason sought to explain the failure to produce the desired result. A reduction in microalbuminuria is another metric to assess the success of decreasing the stage of the hypertensive disease.

On the other hand, reduction in total cardiovascular risk entails smoking cessation, treatment of dyslipidemia and disturbances in glucose metabolism, encouraging physical activity, and many other aspects of cardiovascular risk. Arguably, the reduction of blood pressure is perhaps the most important aspect of risk reduction in patients with hypertension.

Technology, however, has complicated the approach to determination of cardiovascular risk. The introduction of computed tomographic (CT) angiography and CT calcium scores tempt some to order these tests perhaps with limited understanding of the natural history of atherosclerosis and its relationship to cardiovascular risk. ⁷ Those who perform cardiovascular risk assessments must be prepared to evaluate the need and cost for these tests, as well as others, before assuming this important responsibility. This has already become a matter of public debate. ⁸

Who Should Perform Staging and Total (Global) Cardiovascular Risk Assessment?

It seems to me that the hypertension specialist, regardless of his or her parent specialty, is best suited to perform the task of global cardiovascular risk assessment. Thus, the assessment should be coordinated by a physician with demonstrated expertise in the areas encompassed by the risk determination (eg, history and physical examination [including waist measurements], interpretation of various types of blood pressure recordings [positional, office, ankle/brachial index, ambulatory blood pressure monitoring, central aortic pressure, augmentation index, reflected waves], interpretation of lipid determinations [eg, total cholesterol, low‐density lipoprotein cholesterol, high‐density lipoprotein cholesterol, triglycerides], and recognition of abnormal blood glucose values [fasting, 2‐hour postprandial, glucose tolerance tests] and insulin resistance).

A physician performing a global risk assessment must be able to determine the need for more advanced studies (eg, electrocardiography, echocardiography, carotid ultrasonography and calculation of carotid intima‐media thickness, coronary calcification scores, and CT angiography) and the need for additional blood tests (eg, homocysteine, human C‐reactive protein, lipoprotein(a)). Such physicians must also clearly understand the need for cardiac stress tests of various types. This may require some additional training or refresher courses for some hypertension specialists. Of course, some hypertension specialists may opt not to conduct extensive cardiovascular risk assessments, but I believe that not to do so would waste an excellent opportunity to fill a clinical void.

A cardiovascular risk assessment does not need to consist of referring a patient to multiple subspecialists (eg, cardiologists, nephrologists, endocrinologists). Again, qualification as a hypertension specialist should indicate the ability to carry out the assessment.

Of course, nurses, nurse practitioners, physician assistants, and technicians of various types will all participate in the acquisition of data. However, in the end, the physician must integrate all of the data, discuss it with the patient, and finally decide on a plan of management.

Not Enough Hypertension Specialists

The daunting task of further reducing cardiovascular morbidity and mortality will require more hypertension specialists than now exist. ASH has as a goal to have at least one specialist for each county (parish) in the United States. Presently, we have 1242 specialists and therefore must encourage others to take the examination. Even evaluating the 30% to 50% of the adult population who have abnormally high blood pressure will be a great task. Although cardiology training programs generally give lip service to preventive cardiology, training in the area of hypertension is sadly lacking.

An effort to promote recognition by third‐party payors of the importance of reimbursement and certification for providing certain services would provide an incentive to increase the number of specialists. Having such a workforce of physicians would clearly be more efficient than the eclectic way in which we approach the problem of cardiovascular risk assessment and management today.

The Importance of Certification

Providers of services included in the cardiovascular risk assessment need to be certified, beginning with the hypertension specialist. Additional proof of the ability to assess need for and interpretation of advanced testing should be provided. Certification also extends to all aspects of data collection, including the measurement of blood pressure in the office, ambulatory blood pressure monitoring, electrocardiography, echocardiography, measurement of blood lipids, and urine analysis. Certification should be tied to reimbursement so that purchasers of such services are assured of reliable assessments.

Proper Cardiovascular Risk Assessment Could Save Money

By eliminating unnecessary testing, appropriately done cardiovascular risk assessment could save money. Such savings would come about primarily by the judicious use of technology. The benefits of improving the duration and quality of life also provide positive economic gains, but the real gains are quantified in humane terms.

It is time to revise our thinking about the staging of hypertension and incorporate the above concepts into the management of total cardiovascular risk. Only then will our patients gain the potential benefits from the therapeutic tools that are already at our disposal. Hypertension specialists should lead the way.