UP FRONT
Hematology Link
In this edition, ASH Clinical News speaks with John J. Ryan, MD, FACC, FAHA,
assistant professor in the Department of Internal Medicine at the University of
Utah, about addressing high blood pressure – its potential hematologic causes
and what hematologists should be aware of.
Managing High Blood Pressure:
The Cardiologist’s Perspective
John J. Ryan, MD, FACC, FAHA
Do you treat many patients for
hypertension who also have hematologic malignancies?
We definitely do, and obviously, some
of that prevalence is due to age. As we
age, the risk of developing hypertension
increases, and, unfortunately, so does the
risk of developing hematologic malignancies. The common risk factor in many of
these circumstances is age.
When and how should the hematologist consult the cardiologist in
the management of patients with
hypertension?
Because hypertension is so common, it
can be difficult to determine the appropriate moment to reach out for a consult or
a referral to a cardiologist. High blood
pressure also carries an increased risk
of cardiovascular consequences such as
strokes, heart attacks, and heart failure,
among others.
If a hematologist is uncomfortable
managing a patient with high blood
pressure, he or she should refer to the
cardiologist; for instance:
• if the blood pressure is persistently
elevated despite best efforts
• if there is concern about complications from the high blood pressure,
such as damage to the heart
• if the hematologist is worried about
a patient’s risk of stroke, or if the
patient has had a stroke in the past
Patients with hematologic malignancies
are sometimes referred to the tertiary care
centers for their cancer treatments, and,
in that setting, the staff may be unfamiliar
with the patient’s background and full
cardiac history; in that circumstance,
again, it’s reasonable to get the cardiologist involved.
Ultimately, when patients are undergoing treatment for a hematologic malignancy, it’s important that the clinician not lose
sight of the fact that he or she may have or
have previously had high blood pressure.
ASHClinicalNews.org
Does hypertension contribute to
a greater risk for blood clots and
thrombosis? What is the role of the
platelet in this?
Hypertension does increase the risk of
having a clinical event, as well as organ
damage; many of these effects are mediated through the development of clots.
So, yes, hypertension does contribute to a
patient’s thrombotic risk.
As hematologists know, most clots
are developed through platelet activation; how hypertension interacts with
platelet activation is very challenging.
There are two general approaches to
treating hypertension and its clinical
consequences: anti-hypertensive agents
(such as beta-blockers, ACE inhibitors,
calcium channel blockers) to lower the
blood pressure, and antiplatelet agents
(such as aspirin) to inhibit platelet
aggregation and lower the risk of the
associated clinical events.
Ultimately, what we try to do is prevent the clinical consequence of this platelet activation. We can know that platelets
are activated, but that activation becomes
much more important when the patient
has a clinical event (a heart attack, a
stroke, etc.). With anti-hypertensive medications, therefore, the goal is to decrease
the risk of the clinical consequences of
platelet activation.
Are there causes of high blood
pressure potentially related to hematologic conditions?
The overproduction of red blood cells
and high hematocrit levels associated
with polycythemia vera can contribute to
systemic hypertension; high hematocrit
levels have been found to interfere with
the vasodilatory effects of nitric oxide.
The treatment of polycythemia, which
can involve phlebotomy, can alleviate
the systemic hypertension, as well as the
physiological consequences of having a
high red blood cell count.
Again, I have to stress that the common risk factor is age, and, with the
aging population, both hypertension and
hematologic malignancies are increas-
ingly more common. Clinicians need to
remember that none of this is happening
in a vacuum. We need to be cognizant
that, when we are caring for a patient and
see another issue that we are uncomfortable with, we can ask for help.
Hypertension is
present in many
patients with
hematologic
malignancies.
The common
risk factor is age.
Are there any special hypertension
treatment concerns for patients
who might be on chemotherapy?
Certain treatments for cancer and hematologic malignancies have the development of hypertension as a side effect. With
newer medications, we might not know
yet if hypertension is a side effect. But we
do definitely see that – and I get the impression that we are seeing it more often.
The priority, obviously, is to cure the
malignancy or to treat the cancer. But,
again, we need to be aware that another
condition may have developed over the
course of the treatment, and this condition can also have consequences on the
life and health of the patient. We always
treat the hypertension along with the
cancer in these instances. ●
ASH Clinical News
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