All concepts, explanations, trials, and studies have been
re-written in plain English and may contain errors. I am
not a doctor
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Jon's Note: This was a re-analysis of older trial data,
not an actual trial. Nonetheless, it is something every
person with coronary artery disease (also called
coronary heart disease) should know.
	Systolic pressure is the pressure when the
heart is pushing blood out into the body. Diastolic 
pressure is the pressure when the heart is filling with
blood coming back to it from other parts of the body.

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June 20, 2006 - According to analysis of the INVEST trial,
lowering diastolic blood pressure too much in patients with
coronary heart disease may be harmful.
	Researchers call this the "J Curve" - an increased
risk of death with large reduction in blood pressure. The
heart gets most of its own blood supply during the filling
phase (diastole). So patients with low filling pressures
(diastolic HF) or with limited blood supply to the heart
(CAD or coronary artery disease) probably suffer from the
"J Curve" most.
	Looking for a J Curve, researchers analyzed data
from the INVEST trial, which compared two blood pressure
lowering therapies in 22,576 patients with high blood pressure
and CAD. Results showed J-shaped relationships between
both systolic and diastolic blood pressures and the primary
endpoint of all-cause death, nonfatal heart attack or nonfatal
stroke. However, the J curve was much clearer for diastolic
blood pressure.
	THE HEAD RESEARCHER SAID THAT
WHEN DIASTOLIC PRESSURE IN THESE PATIENTS
WENT BELOW 70, MORTALITY DOUBLED; AND
WHEN IT DROPPED BELOW 60, MORTALITY
QUADRUPLED. This seems to only apply to people with
CAD, sometimes called CHD for coronary heart disease.

Some doctors claim that there are other reasons these patients
have poor outcomes. They say that the heart-related events are
from high systolic blood pressure, which causes higher pulse
pressures.
	However, when trying to lower systolic pressure,
you usually lower diastolic pressure at the same time. So, if
you have CAD, you should talk with your doctor about how
much you want to lower your blood pressure (both numbers)
before lowering them too far.
	Dr William Cushman and other researchers also
published an analysis of the SHEP trial. This study also
showed that too-low diastolic pressure is linked to higher risk
for heart-related events.

Some information does contradict the J-Curve being harmful
theory. Three studies have shown no benefit but also no harm
from very low blood pressures - but these patients had kidney
disease, not coronary heart disease.
	The HOT study tested the diastolic J-curve theory
as well, but did not show higher or lower risk. In that study
though, the groups had very little pressure differences between
groups.

It really looks like 80 should be the goal for the lower
(diastolic) blood pressure number in patients with CAD
or high blood pressure, unless this leaves the upper number
(systolic) over 140 mmHg.

Title:       Dogma disputed: Can aggressively lowering blood
               pressure in hypertensive patients with coronary artery
               disease be dangerous?
Source:   Ann Intern Med 2006; 144:884-893.
Authors: Messerli FH, Mancia G, Conti R, et al.