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Electronically Controlled Coronary Arteriography '

HAROLD C. URSCHEL, JR., M.D., EARL J. ROTH, MI.D.666

Froiti the Na va(l Alc(liCol Rcsa(lrchl IJ.s-titite, NootolUd N(av(alAIc(1ical CcoItcr,

Betles(lda, Maryland

Introduction

To INCREASE the safety and reliability of

coronary arteriography is desirable. An approach

to this problem was the development

in our laboratory of an electronic

apparatus which completely eliminates the

variables innate in any manual operation.

The sequence of electronically controlled

events is triggered by either the electrocardiographic

R-wave or the aortic systolic

pressure wave. The dye is automatically

injected during that fractional phase of the

cardiac cycle which allows for the maximum

coronary filling with the minimum

quantity of radio-opaque material. At the

precise moment following injection which

has been determined to give a consistent

visualization of the coronary arteries with

a single exposure, the x-ray machine is

automatically fired. This apparatus should

provide both the clinician and the researcher

with an improved diagnostic adjunct

in the study of coronary artery disease.

Most prior attempts at coronary arteriography

have had a fundamental similarity;

namely, the injection of massive quantities

of contrast medium in order to fill the coronary

vessels. The effort has been directed

' Submitted for publication September 23,

1958. * Surgical Service, Massachusetts General

Hospital, Boston, Massachusetts.

.*. Surgical Service, University of Texas MIedical

Branch, Galveston, Texas.

f Acknowledgment is gratefuilly given to Maynard

Eicher, Electronic Scientist, for aid in design

and construction of the electronic apparatus.

The opinions or assertions contained herein are

the private ones of the writers and are not to be

construed as official or reflecting the views of the

Navy Department or the naval service at large.

toward overpowering cardiac physiology

rather than toward utilizing it. From the

time Rousthoi 23 first demonstrated the

coronary arteries of the rabbit roentgenographically,

numerous attempts have been

made to visualize the coronary arteries in a

variety of species including man. Most investigators

have preferred to inject the dye

through a catheter into the region of the

coronary ostia; the catheter being inserted

in a retrograde manner, entering the aorta

through a wide variety of its branches.1'' 3

5, 6, 8, 10, 12, 13. 14, 15, 17. 18, 20, 22, 24 Others have

introduced dye to the coronary arteries

through a needle placed directly into the

ascending aorta by means of a transthoracic

puncture; this method has not

been without disastrous results.4, 21 Attempts

to automate the method of dye injection

and the firing of the x-ray apparatus

have been made.9 16 Many of these procedures

have been augmented by the rapidfire,

multiple-exposure x-ray machine.3 1. 25

Despite the variety of dye injection technics

and x-ray firing mechanisms available to

the clinician today, there still remains a

marked hesitancy to perform diagnostic

arteriography in the presence of coronary

artery disease. This is not only the result

of certain inherent technical hazards, but

principally because of the potential toxicity

of the large amount of dye necessary to

assure adequate coronary visualization utilizing

present-day methods in this group

of patients. Flomm 7 and Hase II have confirmed

the occurrence of reactions secondary

to the injection into the coronary arteries

of presently available radio-opaque

dyes. These complications range from

275


276 URSCHEL

simple cardiac arrhythmias and secondary

hypotension to convulsions and neurotoxic

death.

Using our electronically controlled apparatus,

a small quantity of dye is automatically

injected into the region of the coronary

ostia during that fractional phase of

the cardiac cycle when physiological filling

of the coronaries occurs, greatly reducing

the dangers of contrast medium toxicity. A

single radiograph is then taken automatically

at the exact moment of maximum

coronary filling. This eliminates the need

for multiple exposures to obtain a satisfactory

arteriogram. By avoiding the inconvenience,

cost and radiation hazard of the

rapid-fire, multiple-exposure x-ray machine,

the method of coronary arteriography to be

presented remains simple, thereby extending

even more its application and usage.

Method

Healthy adult male mongrel dogs ranging

in weight from 25 to 30 Kg. were used.

The animals were anesthetized with intravenous

pentobarbital sodium. Lehman #12

cardiac catheters were inserted into the left

femoral and right carotid arteries through

cutaneous cut-downs. In each case the distal

artery was then tied off with a 3-0 silk

ligature. Similar 3-0 silk ligatures were

placed under the vessels on the cardiac side

of the insertion pending definitive placement

of the catheters at which time these

too were secured. The femoral catheter,

terminating in a Statham strain gauge, was

advanced well into the abdominal aorta.

The carotid catheter, terminating in an attachment

to a solenoid valve (Fig. 2),

was advanced under fluoroscopic visualization

in a retrograde manner to within a few

millimeters of the aortic valve leaflets. Positioning

of the carotid catheter was extremely

important in order to prevent its

tip from lying in the blind caudal cusp.

Clotting within the catheters was prevented

by intermittent flushing with heparinized

saline. However, once the carotid catheter

> A.ND ROTH Annals of Surgery

August 1959

was filled with dye, no clotting occurred

even if flushing were omitted. The catheters

were now ready for attachment to the automatic

coronary arteriography apparatus.

Both the equipment and the electronic

controls for this method of coronary angiography

are described in the Appendix.

In order to evaluate the effectiveness of

this instrument both partial and total obstructions

were created in the mainstem

and branches of the circumflex, anterior

descending and right coronary arteries.t

Partial blocks were established by placing

a 5-0 silk ligature around an artery, incorporating

within the tie an interposed

mosquito-tipped hemostat. The hemostat

was then withdrawn, producing only a narrowing

rather than total obstruction of that

vessel. Complete obstructions were created

by looping a long 5-0 silk ligature under an

artery at the desired location, bringing

the loose ends outside the chest wall without

tying down on the vessel. Prior to dye

injection, the loose ends were pulled up,

producing temporary total occlusion, being

released immediately following x-ray exposure.

In this manner ventricular fibrillation,

which frequently follows prolonged total

occlusion of the circumflex and anterior

descending coronary arteries, was prevented.

In all instances the chest incision

was closed prior to the taking of the coronary

arteriogram. Control of the long ligatures,

necessary to temporarily create total

occlusion, was maintained through the

closed incision.

The radio-opaque contrast medium used

throughout the development and evaluation

of this apparatus was Miokon ft which was

used in concentrations of 30, 50, and 90

per cent.

f Anatomic terminology for coronary arteries of

the dog was adopted from Moore's classical description.17

it Miokon Sodium 30%, Miokon Sodium 50%,

and Miokon Compound 90%o, radio-opaque contrast

medium was generously contributed by the

Mallinckrodt Chemical Works of St. Louis, Missouri.


ELECTRONICALLY CONTROLLED CORONARY ARTERIOGRAPHY

Volume 150

Number 2

The x-ray technic involved these settings:

220 milliamperes at 0.1 second; 70 KVP;

39-inch cone distance; and a Bucky with

screens at par speed. To determine the

ideal positioning for optimum coronary

visualization, exposures were made from

both the right and the left with the subject

in the lateral and oblique positions.

Experimental Design

Following the development of a reliable

electronic instrument with multiple variable

controls, the fundamental goal was twofold.

It was desired to determine, first, the optimum

moment within a cardiac cycle for

the injection of a minimum quantity of dye

that would provide for complete coronary

filling and, second, following dye injection,

at what succeeding phase of the cardiac

cycle would x-ray exposure reveal maximum

coronary filling.

Multiple injections with different concentrations

of Miokon were carried out. Many

combinations of dye injection delays and

x-ray firing delays were explored. Contrast

medium was introduced to the coronary

ostia during all fractional phases of the

cardiac cycle. Following each of the cyclic

variations of dye injection, numerous x-rays

were taken in two distinctly separate manners.

In one group the onset of dye injection

was held constant and the x-ray delay was

varied, while in the other group the interim

between dye injection and x-ray was held

constant, with different absolute times, and

the time of dye injection was varied. This

was done to define dye diffusion time

through the coronary arteries for a given

viscosity and heart rate and, once determined,

to establish to what degree phasing

of the cardiac cycle affected the time of

maximum coronary filling. The pressure

and duration of dye injection were independently

varied to investigate their proper

combination to effect the most efficient

coronary filling.

After the control settings for optimum

function were determined, the apparatus

277

was evaluated for its ability to demonstrate

the artificially produced coronary artery

blocks.

Results

The electronic apparatus operated in a

reliable and consistent manner, successfully

firing the series of more than 500 x-rays

needed to complete this study. The range

and sensitivity of each variable function

were adequate to provide the diversification

deemed necessary and desirable.

Relationship of Dye Injection to Phase

of Cardiac Cycle: Two variables were involved

in establishing the relationship of

dye injection to phase of cardiac cycle as

it pertained to achieving maximum coronary

filling: the optimum moment within a

cardiac cycle for the dye injection and the

minimum necessary quantity of dye. Derivation

of these two variables was achieved

by empirically altering one and then the

other until the optimum values were discovered.

One cc. of dye was established as

the minimum necessary amount to consistently

fill the coronary tree, providing it

were injected in the ideal phase of the

cardiac cycle. Injection during any other

phase of the cycle would result in inadequate

filling and x-ray visualization. Dosages

less than one cc., 0.6 and 0.8 cc., failed

to yield satisfactory results regardless into

which cyclic phase they were introduced.

The ideal fraction of the cardiac cycle

for injection of the minimum amount of dye

to produce complete coronary filling was

found to be early to mid-diastole. If injection

of the "minimum" amount of dye were

delayed into mid-diastole, late diastole or

early systole, only partial filling of the coronary

arteries resulted.

Relationship of X-ray Exposure to Dye

Injection Time: The moment of complete

coronary filling after dye injection, and

therefore the ideal time for x-ray exposure,

was also derived empirically from analysis

of the previously mentioned data. Because

our apparatus fired a single x-ray exposure,


278

URSCHEL AND ROTH

IA

1B

Annals of Surgery

August 1959

FIG. 1. Coronary arteriograms taken with our apparatus, using only one cc. of contrast material. Obstructions

were demonstrated in the coronary arteries and their branches. 1A. A distal total and a more

proximal partial obstruction of the anterior descending. 1B. A partial block of the circumflex, and a


Volume 150

Number 2

ELECTRONICALLY CONTROLLED CORONARY ARTERIOGRAPHY 279

IC

11)

distal obstruction of the anterior descending. 1C. Distal obstructions in both the anterior descending and

circumflex. ID. Total obstruction of the anterior descending.

*

*

7


280 URSCHEL AND ROTH Annals of Surgery

280 ~~~~~~~~~~~~~~~

a multitude of different x-ray delays fol- in a concentrated mass within the sinuses of

lowing dye injection in any given part of Valsalva through the next systole with only

the cardiac cycle was necessary to be cer- an inconsequential amount being lost up

tain that the moment of complete filling the ascending aorta.

was not missed. For each different dye (2) Heart rate: Cardiac rate became a

viscosity and heart rate there is a certain significant factor in our experiments only

time necessary for the medium to pass when it exceeded 180. With rates in excess

from the coronary ostia to the distal coro- of this figure, the viscosity of Miokon Sonary

branches. In addition to this physical dium 50 per cent did not allow the dye to

dispersion factor, the phase of the cardiac reach the distal coronary tree by the end

cycle in which the dye is injected influences of diastole.

its diffusion through the coronaries. With Relationship of Duration of Dye Injecthe

minimum amount of dye injected dur- tion to Dye Injection Pressure: The quaning

early diastole maximum filling occurred tity of dye delivered from the tip of a

at the end of the same diastolic phase. given catheter is dependent upon both the

Roentgenograms taken during systole ex- pressure under which the dye is injected

hibit slight blurring, diminishing definition. and the duration through which the injec-

Further exploration of the cardiac phase tion occurs. With both pressure and duraeffect

on filling, with artificially produced tion variable, it is possible to introduce a

bradycardia, is presently under study. specific quantity of dye in two fundamen-

Several factors were noted to influence tally different ways-namely, through a

the relationship of dye injection to phase short duration under high pressure or

of the cardiac cycle and to time of x-ray through a longer duration under lesser

exposure. pressure. Our results showed that durations

(1) Viscosity: Concentration of dye is up to one-fifth of the total time lapse of

directly related to contrast provided on one cardiac cycle would consistently allow

roentgenograms and physical dispersion for complete filling of the coronaries. With

through the vessels. Miokon Sodium 50 per canine heart rates of 120, a typical figure,

cent proved to be the ideal contrast mate- the duration of dye injection should prefrial

for our investigation, possessing a vis- erably not exceed 0.1 second. Durations

cosity which allowed for injection and much in excess of this figure usually recomplete

filling of the coronaries within the sulted in inadequate uptake of the dye by

same diastolic phase, still providing satis- the coronary arteries. After testing many

factory contrast. Thirty per cent Miokon, combinations of duration and pressure, a

although it diffused equally as well through duration of one-tenth of a second was

the vessels, did not exhibit satisfactory con- adopted as a standard. Thereafter, variatrast

when used in one cc. quantities. The tions in pressure were used to make any

best contrast was achieved with Miokon given catheter yield the desired amount of

Compound 90 per cent. However, its vis- dye. Pressures as high as 100 pounds per

cosity, requiring higher injection pressures square inch were used without detrimental

and increased durations, delayed coronary effects as monitored by the ECG and aortic

filling until well into the next cardiac cycle pressure tracings. However, to inject one

following injection. If introduced during cc. of 50 per cent Miokon through a #12

early diastole of one cardiac cycle, maxi- catheter in 0.1 of a second required only

mum visualization did not occur until 5 to 10 pounds per square inch.

diastole of the next cycle. In spite of its Demonstration of Coronary Artery Obfilling

delay, if it were injected in early structions: Both partial and total blocks in

aiastole, the 90 per cent dye would remain the main coronary arteries and their larger


Volume 150

Number 2

branches were consistently demonstrated.

Obstructions in the smaller peripheral arteries

were usually elucidated although,

upon occasion, that portion of the vessel

just proximal to the obstruction failed to

fill with contrast medium. By increasing the

quantity of dye to two cc. these difficult

to demonstrate obstructions invariably were

well outlined. The right coronary artery

was clearly visualized with the animal in

the oblique positions; however, it was often

obscured by the anterior descending vessel

in the lateral view. Representative arteriograms

exhibiting total and partial blocks

of various coronary artery branches are

presented in Figure 1. Each was achieved

with the automatic injection of one cubic

centimeter of Miokon Sodium 50 per cent

(during early diastole). In every case the

x-ray was taken at the end of the same

diastolic cycle. An example of such an ideal

tracing is shown (Fig. 4B).

Contrast Medium Toxicity: With the

small quantities of Miokon necessary to

visualize the coronary tree by the method

described, there was no evidence at any

time of dye toxicity: hypotension, arrhythmias

or neurologic signs. No deaths could

be attributed to Miokon even on an accumulative

basis, despite the fact that

sometimes as much as 250 cc. were injected

into the root of the aorta of a single animal

during a four- to six-hour period.

ELECTRONICALLY CONTROLLED CORONARY ARTERIOGRAPHY

Discussion

Utilizing electronics to consistently reproduce

a precalculated chain of events

culminating in a satisfactory coronary arteriogram

with the use of only a single cc.

of contrast medium greatly increases the

safety of this diagnostic tool. Aside from

the occasional patient who is sensitive to

iodinated compounds, the toxicity of such

materials appears to be proportional to

the quantity employed. Risk is further reduced

through the high degree of reliability

and consistency of the apparatus. Prior to

the actual injection of dye, the entire se-

281

quence of predicted events can be checked

and rechecked by making use of the test

firing circuit. With only a single dye injection

and one x-ray exposure necessary, this

apparatus avoids the difficulties inherent

in multiple injection procedures and rapidfire,

multiple-exposure machines.

Elevation of the apparatus presented

from animal research to clinical use appears

both practical and logical. For such application

a single calibrated cardiac catheter

would be sufficient. Through a brachial

artery cut-down, following fluoroscopic

positioning of the tip near the coronary

ostia, simultaneous tracings of the patient's

ECG and aortic pressure could be recorded.

The cardiac catheter would then be

switched from the strain gauge to the output

of the solenoid-operated valve. Using

the procedure described in the Appendix

the operator would have to transpose the

time relationship from the aortic pressure

tracing to the ECG tracing. As confirmed

by animal experimentation this relationship

is not the same from subject to subject,

but it is consistent within a single patient

from one cardiac cycle to another, provided

the heart rate remains fairly constant.

With the apparatus set to automatically fire

from the electrocardiographic R-wave and

with the variable controls adjusted to positions

anticipated to be ideal, a test run

could be carried out. By repeated adjustments

of the various variable delays and

test firings, the exact desired settings would

readily be achieved. A satisfactory coronary

arteriogram could be predicted with

the first and only injection of dye.

For human arteriography the quantity of

dye might have to be increased to more

than one cc. inasmuch as the coronary

bed of an adult human is larger than that

of a 35-kilogram dog. On a cubic-centimeter-of-dye

to kilogram-of-weight basis,

probably two to four cc. of dye would be

adequate.

In view of the relationship between dye

viscosity and heart rate, it could be postu-


282

lated that with a given heart rate of 60,

the more viscid Miokon Compound 90 per

cent would have adequate time to fill the

coronaries within a given single diastolic

episode. Because of the low toxicity and

superior contrast, Miokon Compound 90

per cent may well prove to be the dye

of choice for human arteriography in that

patient with some degree of bradycardia.

In the dog under pentobarbital sodium

anesthesia bradycardia has not been observed

and the above posttulation h.as not

been evaluated.

All parts of this apparatus whiclh come

directly into contact with either the dye or

with the patient are easily sterilized, facilitating

clinical application.

URSCHEL AND ROTH Annals of Surgery

AuguLst 1959

I

FiG. 2. Pressure injector

with control unit.

Compressed carbon dioxide

is delivered to the

top of the plastic coluimn

containing contrast me-

diuim. Injection of contr.ast

mllediuim is regulated

by the solenoid valve at

the base of the coluimn.

In addition to improving the diagnosis of

coronary artery disease and localizing of

obstructions for medical purposes, this tool

may aid the surgeon in deciding whether to

use a direct or indirect method to increase

the flow of blood to an ischemic heart. Following

any type of revascularization procedure,

it would allow the physician to better

evaluate the results of surgical therapy,

difficult to determine under any present

method of assay. In the laboratory this

app)aratus not only provides for an inexpensive,

reliable and convenient method

of assessing surgical procedures carried out

directly upon the coronary arteries but also

a means to investigate coronary artery flow

and the physiology of filling. It can also


Volume 150

Number 2

ELECTRONICALLY CONTROLLED CORONARY ARTERIOGRAPHY

FIG. 3. Block diagram for electronically controlled coronary arteriography.

function as a dye injector for arteriography

of most other vessels.

Current work is being performed in an

effort to adapt this apparatus to angiocardiography.

In addition, carbon dioxide

is being evaluated with regard to its use

as a contrast medium for coronary arteriography.

Summary and Conclusions

1. An electronic apparatus with electrocardiographic

control is presented which

performs coronary arteriography with increased

safety and reliability. It is completely

automatic, injecting a small amount

FILM

283

of dye during any preselected fractional

phase of the cardiac cycle and then exposing

a single x-ray film at the time of optimum

coronary filling.

2. One cc. of Mioken Sodium 50 per cent

was established as the minimum and consistently

adequate quantity of contrast medium

to provide visualization of the coronary

arterial tree in a 35-kilogram dog.

3. Early diastole was found to be the

ideal phase of the cardiac cycle for injection

of a minimum amount of dye, utilizing

cardiac physiology to achieve maximum efficiency

of coronary artery filling.


284 URSCHEL AND ROTH

Annals of Surgery

4. The optimum time of x-ray exposure

-the moment of maximum coronary filling

with dye-for our experimental conditions

was established as being at the end of the

same diastolic period in which the dye was

injected.

5. Factors not directly related to the

cardiac cycle which influence coronary artery

uptake and distribution of contrast dye

include pressure under which the dye is injected,

duration of injection, dye viscosity

and cardiac rate. Each of these factors is

individually discussed.

6. Total and partial obstructions of both

large and small coronary arteries were produced.

Each was demonstrated roentgenologically.

7. With the method described, wider application

of coronary arteriography can be

made in medical and preoperative diagnoses,

in the evaluation of direct and indirect

surgical procedures to increase the

blood supply to the heart and in the investigation

of the physiology of coronary flow.

Appendix

Description of Equipment and Electronic

Control Mechanism for Automatic

Coronary Arteriography: A dual channel

Twin-Viso Sanborn Recorder was employed

to monitor the animal's electrocardiogram

and aortic pressure. The marker stylus was

used to monitor the functions of the electronic

apparatus. The upper tracing, channel

A, recorded the ECG, being connected

to the animal in the usual manner via four

standard leg leads and the Sanborn ECG

pre-amplifier. The lower tracing, channel B,

recorded the animal's aortic pressure via

the femoral catheter, Statham strain gauge

and the Sanborn strain gauige amplifier.

The calibrated plastic column (Fig. 2B)

which allows visual monitoring of the exact

quantity of dye injected eaclh time?, was

filled from above with the radio-opaquie

contrast medium. It was then connected by

a high pressure hose to a tank containing

100 per cent carbon dioxide under pressure.

August 1959

The pressure upon the dye was regulated

by the pressure-reduction valve atop the

carbon dioxide cylinder. The outlet of the

dye column terminated in a rapid-action outflow

solenoid-operated valve. The first position

of a three-way stopcock was adapted

to the outlet valve. The second position was

connected to a source of heparinized saline

under pressure slightly in excess of aortic

blood pressure. To remove any residual air

that may have been trapped below the dye

in the column or in the solenoid-operated

valve, the apparatus was fired at this stage

of the procedure. The carotid catheter,

which also had been temporarily connected

to a source of heparinized saline, was now

connected to the third position of the threewvay

stopcock. Upon flushing the catheter

once more, the apparatus was ready for use.

All parts of the equipment which contact

the dye can be sterilized.

The sequence of events involved in this

automatic electronic system can best be

understood by following the block diagram

(Fig. 3). At the discrimination of the operator,

the chain of automatic events can be

triggered by the action potential arising

from the peak wave of either the electrocardiographic

R-wave or the aortic systolic

pressure wave.* In addition to the fire

switch on the main panel a remote control

was included to permit operation from a

protected area.

The output of the peak wave discriminating

circuit consists of a single monophasic,

sharply peaked, electronic impulse which is

fed independently to two variable delay

control circuits-the dye injection delay

control and the x-ray firing delay control.

v To assuire that only a single peak wave from

any comiiplete cycle will be consistently discriminated,

the amplified output potential of the ECG

pre-amplifier or the strain gauge amplifier is increased

or decreased to the point where only a

single peak wave creates suifficienit potential to

exceed the discrimiiinator's threshold. Having a fixed

bias, the sensitivity of the discriminator remains

constant; being capacitance coupled, a rising potential

is necessary.


Volume 150 ELECTRONICALLY CONTROLLED CORONARY ARTERIOGRAPHY

Number 2

As the signal from the peak wave discriminating

circuit passes through the dye

injection delay circuit, it is delayed for a

preselected fraction of a second, following

which it activates the solenoid valve to

open, initiating injection of a radio-opaque

dye. At the exact moment that the dye injection

commences, the dye injection duration

control circuit is activated. Following

another preselected interval of time, this

circuit deactivates the solenoid valve, causing

it to close, terminating the injection of

the dye.

As previously stated, the signal from the

peak wave discriminating circuit passes independently

to the x-ray firing control.

Likewise, following a preselected interval

of time, this impulse passes on to the x-ray

switch, and a single roentgenogram is exposed.

A safety device is incorporated

which prevents the apparatus from firing

again until a "reset" switch is pushed.

Both the dye injection and x-ray fire delays

are equipped with a pair of calibrated

variable controls, coarse and fine. The

coarse control allows for tenths of a second

(0.1 second) variation while the fine vernier

control is continuously variable, easily

allowing for hundredths of a second (0.01

second) variation. The dye injection duration

control is calibrated in tenths of a

second ( 0.1 second ). For purposes of investigation,

the following calibrated limits

were installed:

Dye injection delay control 0.01 to 0.60 seconds

Dye injection duration control 0.1 to 0.6 seconds

X-ray firing delay control 0.10 to 1.10 seconds

Any of these absolute time limits could

easily be extended, and a finer vernier could

be incorporated into the dye injection duration

control circuit if the application proved

it necessary. It was of prime concern during

the development of this apparatus that the

setting of each time-delay control should be

independent of the other time-delay control

settings. The duration control setting, independent

of the other variable control set-

285

tings, must be dependent on the onset of

the duration period for obvious reasons,

since it fuinctions only to close the solenoid

valve.

I)espitc the calilbration accuracy of the

time delay controls, it was found most desirable

to visually monitor the time relationship

of each of the electronically controlled

events taking place in respect to

each other and in respect to the cardiac

cycle."* To accomplish this, the marker

stylus of the Sanborn Twin-Viso machine

was inactivated from its time-impulse generator.

In our apparatus it was utilized as

a marker to indicate the sequential occurrence

of each electronically controlled

event: onset of dye injection, cessation of

dye injection and the moment of x-ray exposure.

With the occurrence of the latter

event, the marker was made to continue to

mark until the apparatus was put into the

"reset" position preparatory to taking another

coronary arteriogram.

Figure 4 graphically demonstrates the relationship

of all the events via three simul-

It is not always possible to determine with

accuracy exactly where in a cardiac cycle the zerotime

reference point can be found. This point, from

which the dye injection onset and x-ray firing moment

are determined via their respective delays, is

consistent within any cardiac cycle. This reference

point is that exact moment when the rising resultant

potential of a maximum wave passes the

threshold sensitivity of the peak wave discriminator.

If the operator wishes to trigger the chain

of electronically controlled events with the R-wave

of the ECG, having a rise-time of extremely short

duration, the peak of this wave can be considered

synonymous with the zero-time reference point for

this tracing. However, if he chooses to trigger the

chain of electronically controlled events using the

aortic systolic pressure wave, the zero-time reference

point cannot be determined by merely viewing

the pressure wave tracing, for the rise-time of

this wave is much longer than the rise-time of the

ECG R-wave. At exactly what phase of the aortic

systolic pressure tracing does the resultant potential

pass the discriminator's threshold remains obscure,

but it is always somewhat prior to the wave's maximum

excursion. In this case, to monitor the time

relationship of each of the electronically controlled

events becomes not only desirable but necessary.


286 URSCHEL AND ROTH Annals of Surgery

August 1959

I

AORTIC

PRESSURE

TRACING

Al A2 B Cl Dj

MARKER 'Lwj

BEGIN END

DYE X-RAY

INJECTION FIRING

FIG. 4A. A schematic tracing demonstrating the electronic events for an ideal control setting. A (1 or 2)-

Zero-time reference point. A-B-Dye injection delay. B-C-Dye injection duration. A-D-X-ray delay.

taneous tracings: (1) the electrocardiographic

tracing, (2) the aortic pressure

wave tracing and (3) the tracing indicating

the sequential occurrence of specific electronically

controlled events.

Within the electronic apparatus a test

circuit is included which simulates the entire

sequence of events. Although the dye is

not actually injected nor is the roentgenogram

exposed, these events, together with

all other events, are recorded by the Twin-

Viso Sanborn Recorder, giving the operator

the opportunity to visually monitor the

exact chain of events that will occur, all

in true time relationship to the cardiac

cycle. This circuit allows the operator, by

repeated test firings, to confirm the exact

delay and duration settings desired, assuring

a good result with the first x-ray

exposure.

The amount of dye injected is dependent

upon several factors: the duration of injection,

the pressure of the compressed carbon

dioxide upon the reservoir column of

contrast medium, the size and length of the

catheter delivering the dye, the viscosity

of the dye and the patient's arterial pressure.

In view of the relatively high pressure

with which the dye is injected, the factor

of the patient'. arterial pressure can be ignored.

It is necessary to calibrate each

catheter with the same dye to be used,

determining in advance how many cubic

centimeters of dye the tip of a catheter

will deliver with the dye under varying

pounds of pressure through varying durations

of injection. With the duration of injection

and the pressure of the carbon dioxide

both readily variable, any catheter can


V'olume 150

Number 2

;+s§P-4;*Xfulf*XlX¢l-;t

; ; ,,

ELECTRONICALLY CONTROLLED CORONARY ARTERIOGRAPHY

* + + + s

t + + + + t * t t + t + + + * +t.

t+4 + ¢

+ + t t -

t 4 + t

.... .,,, ..,. .... .,. ...~~ .. .. . ,. . . ... .,. ..... .,.,,t! t tt

#+,, ++t .++s ttt *tt' ,~~~~~~~~~~~~+. t+ t t 't tt.+ .. t it t ++

;t+t ..; .,,. ... ,w,+ .., ...,tatt *+ i+s, ... .... ... ,,,,++++ +++++

..,. .... .... ....,**. .... .... ..,, .... ...* ,;., .... ..., tt!+ '+!t t+!ttt!+l~~~~~~~~T

T * * I t , I - T . I | T I T t t n t, I T I T | T W~~~~~~~~

FIG. 4B. Tracing demonstrating the actual electronic control settings used for making the arteriograms

shown in Figure 1.

be made to yield the exact quantity of dye Acknowledgment

desired. For their invaluable assistance to this investiga-

A schematic wiring diagram of the elec- tion we are deeply indebted to the members of the

tronic circuits appears in Figure 5. following Naval Medical Research Institute de-

+ t

287


288

URSCHEL AND ROTH

Annals of Surgery

August 1959


Volume 150 ELECTRONICALLY CONTROLLED CORONARY ARTERIOGRAPHY 289

Number 2

partments: Experimental Surgery, Instrumentation,

Radiology, and Photography.

References

1. Barclay, A. E., J. Barcroft, D. H. Barron and

K. J. Franklin: A Radiographic Demonstration

of the Circulation Through the Heart in

the Adult and in the Foetus and the Identification

of the Ductus Arteriosus. Am. J.

Roentg., 47:678, 1942.

2. Broden, B., H. E. Hansson and J. Karnell:

Thoracic Aortography. Acta radiol., Stockh.,

29:181, 1948.

3. Cannon, J. A., C. A. Clifford, G. Diesh and

W. F. Barker: Accurate Diagnostic Coronary

Arteriography in the Dog. Surgical Forum

1955; American College of Surgeons. p. 197.

Philadelphia and London: W. B. Saunders

Co., 1956.

4. Del Campo, C. G. and J. M. Hoyos: Angiography

of the Thoracic Aorta and Coronary

Vessels. Radiology, 50:211, 1948.

5. Di Gullielmo, L. and M. Guttadauro: Roentgenological

Study of Coronary Arteries in the

Living. Acta radiol., Stockh., Supp., 97:1,

1952.

6. Di Gullielmo, L. and M. Guttadauro: Roentgenologic

Visualization of the Coronary Arteries

in Living Subjects. Scientia Medica

Italica, 3:446, 1955.

7. Flomm, R. S., L. D. Maclean and F. J. Lewis:

A Comparison of the Toxicity of Various

Agents Used in Coronary Arteriography. J.

Lancet, 77:431, 1957.

8. Garamella, J. J., V. P. George and L. J. Hay:

A Correlative Study of Peripheral Coronary

Pressure and Coronary Arteriography following

Coronary Occlusion. Surg., Gynec. &

Obst., 105:89, 1957.

9. Gordon, A. J., S. A. Brakius and M. L. Sussman:

Visualization of the Coronary Circulation

During Angiocardiography. Am. Heart

J., 39:114, 1950.

10. Grossman, N.: Visualization of the Coronary

Arteries in Dogs. Am. J. Roentg., 54:57,

1945.

11. Hase, 0. and R. A. Deterling: Evaluation of

Contrast Media Employed for Aortic and

Coronary Visualization. Surgical Forum 1957;

Addendum

Since this article was accepted for publication,

a volume control for regulation of contrast medium

delivery has been incorporated into the apparatus.

It expedites the injection of large amounts of dye

for angiocardiography and aortography.

American College of Surgeons. p. 320. Philadelphia

and London: W. B. Saunders Co.,

1958.-

12. Helmsworth, J. A., J. McGuire and B. Felson:

Arteriography of the Aorta and Its Branches

by Means of the Polyethylene Catheter. Am.

J. Roentg., 64:196, 1950.

13. Helmsworth, J. A., J. McGuire, B. Felson and

R. C. Scott: Visualization of the Coronary

Arteries During Life. Circulation, 3:282,

1951.

14. Hughes, C. R., R. Sartorius and W. J. Kolif:

Angiography of the Coronary Arteries in the

Live Dog. Cleveland Clin. Q., 23:251, 1956.

15. Jonsson, Gunnar: Visualization of the Coronary

Arteries. Acta radiol., Stockh., 29:536,

1948.

16. Levy, L. M., D. W. Hannon, J. L. Sprafka and

I. D. Baronofsky: A Method for Coronary

Arteriography. Ann. Surg., 143:412, 1956.

17. Miller, E. W., W. J. Kolff and C. R. Hughes:

Angiography of Coronary Arteries in the

Live Dog. II. Detection of Abnormalities.

Cleveland Clin. Q., 24:41, 1957.

18. Miller, E. W., W. J. Kolff and C. R. Hughes:

Angiography of Coronary Artery in Dogs.

Cleveland Clin. Q., 24:123, 1957.

19. Moore, R. A.: The Coronary Arteries of the

Dog. Am. Heart J., 5:743, 1930.

20. Pearl, F., M. Friedman, N. Gray and B. Friedman:

Coronary Arteriography in the Intact

Dog. Circulation, 1:1188, 1950.

21. Radner, S.: An Attempt at the Roentgenologic

Visualization of Coronary Blood Vessels in

Man. Acta radioL, Stockh., 26:497, 1945.

22. Radner, S.: Thoracal Aortography by Catheterization

from the Radial Artery. Acta

radiol., Stockh., 29:178, 1948.

23. Rousthoi, P.: Vber Angiokardiographie; vorlaufige

Mitteilung. Acta radiol., Stockh., 14:

419, 1933.

24. Thal, A. P., R. G. Lester, L. S. Richards and

M. J. Murray: Coronary Arteriography in

Atherosclerotic Disease of the Heart. Surg.,

Gynec. & Obst., 105:457, 1957.

25. Thal, A. P., L. S. Richards and M. J. Murray:

Coronary Arteriography in the Adult Human

Patient. Surgical Forum 1957; American

College of Surgeons. p. 328. Philadelphia and

London: W. B. Saunders Co., 1958.

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