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The recent ACCP consensus statement on medical
therapy of PAH offers the following recommendation regarding
the vasodilator response at catheterization: “Patients
with IPAH, in the absence of right-heart failure, demonstrating
a favorable acute response to vasodilator (defined as
a fall in mean pulmonary artery pressure of at least 10
mm Hg to <40 mm Hg, with an increased or unchanged cardiac
output), should be considered candidates for a trial of
therapy with an oral calciumchannel antagonist. Level
of evidence: low; benefit: substantial; grade of recommendation:
B.” Dr Gaine, how does this recommendation fit into your
usual practice?
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 Sean
Gaine, MD, PhD
Director, Pulmonary Hypertension Unit
Mater Misericordiae Hospital
University College
Dublin, Ireland
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This is a very useful new recommendation. In the past,
before we had effective oral therapy for PAH, calcium-channel
blockers were often used in an attempt to delay the need
for intravenous epoprostenol therapy. Under the new evidence-based
recommendations, unless patients have a true response
to the vasodilator trial, calcium-channel blockers are
avoided.
If someone without right ventricular failure had
a mean pulmonary
artery pressure of 65 mm Hg and it decreased to 50 mm
Hg (ie, did not go to 40 mm Hg or below), would you consider
calcium-channel blocker therapy?
A drop in mean pulmonary artery pressure from 65 mm Hg
to 50 mmHg is no longer considered a favorable response.
Calcium-channel blockers rarely contribute much long-term
benefit in this setting.
Do you use calcium-channel blocker therapy in patients
with PAH but without any vasodilator response, for example,
to control systemic hypertension?
Whenever I see systemic hypertension in a patient with
PAH, I look for underlying medical conditions such as
obstructive sleep apnea. When treatment is required, I
prefer to use an angiotensin-receptor antagonist rather
than calcium-channel blockers. The negative inotropic
effect of calcium-channel blockers, as well as peripheral
edema can be troublesome in PAH patients.
Do you ever add additional therapy (eg, an endothelin
antagonist)
to the calcium-channel blocker in a stable patient with
a good vasodilator response?
If calcium-channel blockers are demonstrated to achieve
the same result as the vasodilator trial, then I generally
stick with monotherapy as long as the patient is stable
and asymptomatic. However, I have added either sildenafil
or bosentan in patients who had a favorable response to
a vasodilator trial, but who have been unable to tolerate
sufficient calcium-channel blocker therapy to achieve
a consistent
mean pressure below 40 mmHg.
The ACCP recommends acute vasodilator testing with
a short-acting agent such as epoprostenol, adenosine,
or inhaled nitric oxide. Which vasodilator do you use
for acute testing and why?
I use inhaled nitric oxide. It is very safe, well tolerated,
and its actions are specific to the pulmonary circulation.
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