“Arterial wall injury and temperature.”

AULUS CORNELIUS CELSUS, 25 B.C.-50 A.D.

For centuries, inflammation-derived heatis known to exist in macroscopic tissues.

However,

Inflammation-derived heat is only recentlyconsidered to exist at the arterial wall.

Active macrophages

UPC’s[1(thermogenine), 2 and 3]

Short-circuitin proton-pump of ATP

Local heat production

Arterial wall temperature elevation(one possible scenario)

PotentialIn vivo thermographic methods

Non-Ivasive Invasive

Non-contact ContactMagnetic Resonance Thermometry (MRT)

Infrared Thermometry (IRT)

Intravascular MRTSingle sensor

Multi sensor

Catheters with flexible arms

Thermographic

baskets

Wall injury and Inflammation

Coronary wall injury and temperature

Purpose of the study: To explore the temperature variations (if any)of the arterial wall following coronary wall injury.

An animal study

Study population/protocol

Non-atherosclerotic pigsSelection of a 60mm area in a normal cor.artery (AOI) 2 thermographic scans in AOI (autom.pullback 0.3mm/sec)

1.5:1 ratio balloon selection.Fwd/Rev movements of the balloon in the AOI, maintaining inflation pressure at 4 atm. (Injury), followed byStable inflation at 12atm for 30sec.2 thermographic scans in AOI (autom.pullback 0.3mm/sec)

Injury

HistologyMacrophage concentration (IS: 0-4 )0 = Rare appearance of histolymphocytes around the stent filament1 = sparsely located histolymphocytes around the stent filament2 = more densely located histolymphocytes covering the stent filament3 = diffusely located histolymphocytes, giant cells, also invading the media

After 4 days2 thermographic scans in AOI (autom.pullback 0.3mm/sec)Sacrifice, and:

Methods

4F over-the-wire catheter4 independent thermistor-sensorsSensitivity 0.01oCMotorized pullback (0.1-0.5mm/sec)

Specifications

Integration of temperature with angiography

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 10 20 30 40 50 60

Pullback distance (mm)

Tem

pera

ture

diff

eren

ce (o

C)

Sensor 1

Sensor 2

Sensor 3

Sensor 4

Before injury

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 10 20 30 40 50 60

Distance (mm)

Tem

pera

ture

diff

eren

ce (o

C)

Sensor 1

Sensor 2Sensor 3

Sensor 4

Immediately after

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 10 20 30 40 50 60

Distance (mm)

Tem

pera

ture

diff

. (oC

)Sensor 1

Sensor 2Sensor 3

Sensor 4

4 days after injury

Macrophage concentration versus temperature

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0 1 2 3 4

IS

oC

temp. increment

P<0.001

Conclusions

•PTCA balloon injury disrupts the temperature homogeneity inside a normal coronary artery.

•This temperature disruption correlates with macrophage concentration at the site of the injury.

•Since local inflammation could initiate hyperplasia and/or promote thrombosis, efforts should be made to minimize wall trauma during coronary interventions.