ISO 5840:1996
(Main)Cardiovascular implants — Cardiac valve prostheses
Cardiovascular implants — Cardiac valve prostheses
Tests to be performed and requirements for test apparatus to be used in determining the physical, biological and mechanical properties of heart valve implantates of all types, and of the materials and components of which they are made. Requirements are provided for preclinical, clinical evaluation and for reporting the results.
Implants cardiovasculaires — Prothèses valvulaires
General Information
Relations
Standards Content (Sample)
INTERNATIONAL
STANDARD
Third edition
1996-l I-01
Cardiovascular implants -
Cardiac valve prostheses
Implants cardiovasculaires - Pro theses valvulaires
Reference number
IS0 5840:1996(E)
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IS0 5840: 1996(E)
Page
Contents
1
........................................................................................
1 Scope
1
...............................................................
2 Normative references
2
3 Definitions .
5
......................................................................
4 Valve description
.................. 5
5 Material, component and valve assembly testing.
7
..............................................................
6 Hydrodynamic testing
13
.......................................................................
7 Durability testing
14
.....................................................
8 Preclinical in vivo evaluation
16
9 Clinical evaluation .
........................................ 19
IO Packaging, labelling and instructions
Annexes
21
A Rationale for the provisions of this International Standard.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
B Materials related to heart valve substitutes
C Physical and material properties of heart valve substitutes and
25
their components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D Standards applicable to testing of materials and components
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
of heart valve substitutes
35
E Definitions of components of a heart valve substitute . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
F Valve description
0 IS0 1996
All rights reserved. Unless otherwise specified, no part of this publication may be
reproduced or utilized in any form or by any means, electronic or mechanical, including
photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
II
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IS0 5840: 1996(E)
0 IS0
Foreword
IS0 (the lnternational Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 5840 was prepared by Technical Committee
ISO/TC 150, implants for surgery, Subcommitte SC 2, Cardiovascular
implants.
This third edition cancels and replaces the second edition (IS0 5840:1989),
which has been technically revised. Additions include testing of materials
and components and a scheme for classification of heart valve substitutes
and their components.
Annexes A to F of this International Standard are for information only.
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0 IS0
IS0 5840: 1996(E)
Introduction
There is, as yet, no heart valve substitute which can be regarded as ideal.
This International Standard has been prepared by a group well aware of
the problems associated with heart valve substitutes and their develop-
ment. In several areas, the provisions of this International Standard have
been deliberately left open as there has been no wish to inhibit
development and innovation. For these reasons, this International
Standard intentionally does not attempt to specify performance require-
ments for finished products. It does specify types of tests, test methods
and/or requirements for test apparatus, and requires disclosure of test
methods and results. The areas with which this International Standard is
concerned are those which will facilitate quality assurance, aid the surgeon
in choosing a heart valve substitute, and ensure that the device will be
presented at the operating table in a convenient form. Emphasis has been
placed on specifying types of in vitro testing, on preclinical in viva and
clinical evaluations, on reporting of all in vitro, preclinical in viva and clinical
evaluations and on the labelling and packaging of the device. Such a
process involving in vitro, preclinical in viva and clinical evaluations is
intended to clarify the required procedures prior to market release and to
enable prompt identification and management of subsequent problems.
With regard to in vitro testing and reporting, apart from basic material
testing for mechanical, physical, chemical and biocompatibility character-
istics, this International Standard also covers important hydrodynamic and
accelerated fatigue characteristics of heart valve substitutes. The exact
test methods for hydrodynamic and accelerated fatigue testing have not
been specified, but requirements for the test apparatus are given.
This International Standard is incomplete in several areas. It is intended to
be revised, updated, and/or amended, as knowledge and techniques in
heart valve substitute technology improve.
IV
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IS0 5840:1996(E)
INTERNATIONAL STANDARD @ IS0
- Cardiac valve prostheses
Cardiovascular implants
1 Scope
1.1 This International Standard specifies tests to be performed and requirements for test apparatus to be used in
determining the physical, biological and mechanical properties of heart valve substitutes of all types, and of the
materials and components of which they are made.
1.2 Requirements are provided for preclinical in viva evaluation, for clinical evaluation, and for reporting the results
of all types of testing and evaluation covered in this International Standard. These requirements do not purport to
comprise a complete test programme.
1.3 Specifications are also given for packaging and labelling of heart valve substitutes.
1.4 This International Standard is not applicable to heart valve substitutes comprised in whole or in part of human
tissue.
A rationale for the provisions of this International Standard is given in annex A.
NOTE -
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain
registers of currently valid International Standards.
IS0 8601 :I 988, Data elements and interchange formats - Information interchange - Representation of dates and
times.
- Part 1: Evaluation and testing.
IS0 10993-I : ----I), Biological evaluation of medical devices
- Part 2: Animal welfare requirements.
IS0 10993-2: 1992, Biological evaluation of medical devices
IS0 10993-3:1992, Biological evaluation of medical devices - Part 3: Tests for genotoxicity, carcinogenicity and
reproductive toxicity.
IS0 10993-4: 1992, Biological evaluation of medical devices - Part 4: Selection of tests for interactions with blood.
IS0 10993-5: 1992, Biological evaluation of medical devices - Part 5: Tests for cytotoxicity: in vitro methods.
Part 6: Tests for local effects after implantation.
IS0 10993-6: 1994, Biological evaluation of medical devices -
IS0 10993-7: 1995, Biological evaluation of medical devices - Part 7: Ethylene oxide sterilization residuals.
lSO/rR 10993-g: 1994, Biological evaluation of medical devices - Part 9: Degradation of materials related to
biological testing.
1) To be published. (Revision of IS0 10993-I :I 992)
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IS0 5840: 1996(E)
Part IO: Tests for irritation and sensitization.
IS0 10993-I 0: 1995, Biological evaluation of medical devices -
- Part I ’!: Tests for systemic toxicity.
IS0 10993-I 1 :I 993, Biological evaluation of medical devices
- Part 12: Sample preparation and reference materials.
2), Biological evaluation of medical devices
IS0 10993-I 2:-
Requirements for validation and routine control -
IS0 11134:1994, Sterilization of health care products -
Industrial moist heat sterilization.
Validation and routine control of ethylene oxide sterilization.
IS0 11135:1994, Medical devices -
IS0 11137:1995, Sterilization of health care products - Requirements for validation and routine control -
Radiation sterilization.
IS0 14155: 1996, Clinical investigation of medical devices.
3 Definitions
For the purposes of this International Standard, the following definitions apply.
3.1 anticoagulant-related haemorrhage: Internal or external bleeding that causes death or stroke, or that
requires transfusion, operation or hospitalization.
NOTE - This definition is restricted to patients who are receiving anticoagulants and/or antiplatelet drugs.
3.2 arterial diastolic pressure: Minimum value of the arterial pressure during diastole.
3.3 arterial peak systolic pressure: Maximum value of the arterial pressure during systole.
3.4 closing volume: Component of the regurgitant volume that is associated with the dynamics of valve closure
during a single cycle (see figure 1).
3.5 cycle: One complete sequence in the action of a test heart valve substitute under pulsatile flow conditions.
3.6 cycle rate: Number of complete cycles per unit of time, usually expressed as cycles per minute (cycles/min).
3.7 external sewing ring diameter: Maximum external diameter of a heart valve substitute, including the sewing
ring (see figure 2).
3.8 forward-flow phase: Portion of the cycle time during which forward flow occurs through a test heart valve
substitute.
3.9 heart valve substitute: Device used to replace or supplement a natural valve of the heart, categorized
according to the position in which it is intended to be used (valve type).
3.9.1 mechanical heart valve substitute: Heart valve substitute composed wholly of synthetic materials.
3.92 biological heart valve substitute: Heart valve substitute composed wholly or partly of animal tissue.
valve substitute, excluding
3.10 internal orifice area: Minimum projected area normal to the plane of the heart
the occluder(s).
eakage through the closed
3.11 leakage volume: Component of the regurgitant volume that is associated with
valve during a single cycle (see figure 1).
NOTE - The point of separation between the closing and leakage volumes is obtained according to a defined and stated
criterion (the linear extrapolation shown in figure 1 is just an example).
3.12
mean arterial pressure: Time-averaged arithmetic mean value of the arterial pressure during one cycle.
2) To be published.
2
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@ IS0 IS0 5840: 1996(E)
3.13 mean pressure difference: Time-averaged arithmetic mean value of the pressure difference across a heart
valve substitute during the forward-flow phase of the cycle.
NOTE - The usage of “mean pressure gradient” for this term is deprecated.
3.14 mean volume flow: Time-averaged arithmetic mean value of the flow across a heart valve substitute during
the forward-flow phase of the cycle.
3.15 nonstructural dysfunction: Abnormality resulting in stenosis or regurgitation of the heart valve substitute
that is not intrinsic to the valve itself.
NOTE - This dysfunction is exclusive of valve thrombosis, systemic embolus or infection diagnosed by reoperation, autopsy
or in vivo investigation. Examples include entrapment by pannus or suture, paravalvular leak, inappropriate sizing, and
significant haemolytic anaemia.
3.16 occluder: Component(s) of a heart valve substitute that move(s) to inhibit reflux.
operative mortality: Death from any cause during operation or within 30 days after operation.
3.17
3.18 profile height: Maximum axial dimension of a heart valve substitute in the open or closed position,
whichever is greater (see figure 2).
3.19 prosthetic valve endocarditis: Infection involving a heart valve substitute.
NOTE - Diagnosis is based on customary clinical criteria, including an appropriate combination of positive blood cultures,
clinical signs (fever, new or altered cardiac murmurs, splenomegaly, systemic embolus or immunopathologic lesions) and/or
histologic confirmation of endocarditis at reoperation or autopsy. Morbidity associated with active infection such as valve
thrombosis, embolus or paravalvular leak is included under this category and is not included in other categories of morbidity.
Closing volume
Leakagevolume
Figure 1 - Example of flow waveform and regurgitant volumes for one cycle
3
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IS0 5840:1996(E)
Occluder
c ---
HHC --
..
/
,
0
/
\
/-
\
/
\
Sewing ring -
\
/I /
2
0
.-
:
aJ
--J
.-
\c
z
a.
Figure 2 - Designation of dimensions of heart valve substitutes
employed to
3.20 reference valve: Heart valve substitute used to assess the conditions established in the tests
evaluate the test heart valve substitute.
NOTE - The reference valve should approximate the test heart valve substitute in type, configuration and tissue annulus
diameter; it may be an earlier model of the same valve, if it fulfills the necessary conditions. The characteristics of the
reference valve should be well documented with both in vitro and clinical data available in the literature.
3.21 regurgitant fraction: Regurgitant volume expressed as a percentage of the stroke volume.
3.22 regurgitant volume: Volume of fluid that flows through a test heart valve substitute in the reverse direction
during one cycle; it is the sum of the closing volume and the leakage volume (see figure 1).
3.23 root mean square (r.m.s.) volume flow: Square root of the time-averaged arithmetic mean square value of
the volume flow through a test heart valve substitute during the forward-flow phase of the cycle.
3.24 simulated cardiac output: Net fluid volume flowing forward through a test heart valve substitute per
minute.
3.25 stroke volume: Volume of fluid moved through a test heart valve substitute in the forward direction during
one cycle.
3.26 structural deterioration: Change in the function of a heart valve substitute resulting from an intrinsic
abnormality that causes stenosis or regurgitation.
NOTE - This definition excludes infection or thrombosis of the heart valve substitute as determined by reoperation, autopsy
or in vivo investigation. It includes intrinsic changes such as wear, stress fracture, occluder escape, calcification, leaflet tear
and stent creep.
3.27 systemic embolism: Clot or other particulate matter, not associated with infection, originating on or near
the heart valve substitute and transported to another part of the body.
NOTE - Diagnosis may be indicated by a new, permanent or transient, focal or global neurologic deficit (exclusive of
haemorrhage) or by any peripheral arterial embolus unless proved to have resulted from another cause (e.g. atrial myxoma).
Patients who do not awaken post-operatively or who awaken with a stroke or myocardial infarction are excluded. Acute
myocardial infarction that occurs after operation is arbitrarily defined as an embolic event in patients with known normal
coronary arteries or who are less than 40 years of age.
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@ IS0 IS0 5840:1996(E)
Isti tute including any covering where it is
3.28 tissue annulus diameter: External d ameter of a heart valve sub I
t diameter of host tis sue (see figure 2).
intended to mate with the smalles
The usage of “mounting diameter” for this term is deprecated.
NOTE -
3.29 valve size: Manufacturer ’s designation of the dimensions of the heart valve substitute.
3.30 valve thrombosis: Blood clot, not associated with infection, causing dysfunction of the heart valve
substitute.
NOTE - Diagnosis may be proved by operation, autopsy, or clinical investigation (e.g. echocardiography, angiocardiography
or magnetic resonance imaging).
4 Valve description
components, materials and processes of construction shall
A complete description of the heart valve substitute, its
be provided.
NOTES
1 See annex E for definitions of terms that can be used to identify the heart valve substitute components.
2 Relevant construction processes may include anticalcification treatment or carbon coating of sewing rings (see annex F).
5 Material, component and valve assembly testing (see A.1 for rationale)
5.1 Principle
Physical testing of the materials and components of heart valve substitutes is performed to assure that the valve or
components will withstand the rigors imposed by the host over the lifetime of the device. Test selection is based
on a matrix criterion that accounts for the materials and components used in the heart valve substitute and the site
of use.
5.2 General
for evaluation shall emulate, as closely as possible, the condition of the finished
he test spe cimen s c hosen
roduct as su pplied for clinical use.
P
5.3 Testing fluid and temperature
Where emulation of in viva conditions is applicable, testing shall be performed using a testing fluid of isotonic
saline, blood or a blood-equivalent fluid whose physical properties (e.g. specific gravity, viscosity at working
temperature) shall be stated. The tests shall be conducted at 37 OC unless an acceptable scientific/engineering
rationale allows for other conditions.
NOTE - Mechanical properties and degradation properties can vary with temperature.
5.4 Biocompatibility
The biocompatibility of the materials and components used in heart valve substitutes shall be determined in
accordance with the appropriate part(s) of IS0 10993.
5.5 Physical and material testing
5.5.1 Materials and component testing
Properties of heart valve substitutes and their components shall be evaluated, where applicable to the design of
the valve, according to tables 1 and 2. A rationale for the selection of properties evaluated shall be provided.
C, D, E and F for references and a description
NOTE - See annexes of possible ma teria Is and component testing of heart
valve substitutes. These annexes are provided to guide the reader in the use of tables 1 and 2.
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@ IS0
IS0 5840: 1996(E)
- Physical and chemical properties for evaluation of heart valve substitute components
Table 1
Componentl)
Clause
Physical and chemical
reference
Synthetic
properties
Biological Metal Ceramic
Textile
(annex C)
polymer
c.2. 1 Bulk physical properties
1 ABCDEHJ 1 ABDJ
2.1 [ Chemical composition ABCDEFGHIJ 1 J 1 FGI
2.2 1 Densitv ABCDEFGHIJ 1 t ABCDEHJ IABDJ I
Liquid diffusivity ABCDEFGHI 1 m-ppmm I ABD I
2.3
ABCDEFGHJ 1 IABCDEHJ IABDJ I
2.4 Hardness
1 ABCDEFGHI I ABCDEHJ IABDJ I
2.5 1 Microstructure/morphology
2.6 1 Tear strenath Dl ABCDEFGHI
2.7 Young ’s modulus ABCDEH ABCDEH ABD
Poisson ’s ratio ABCDEFGHI 1 I ABCDEH ~__
2.8 hD 1
1 Dynamic moduli BDE 1 ABCDEFGHI I I I
2.9
ABCDE ABDH ABD
2.10 Ic oe ff’ tcient of thermal expansion
2.11 1 Glass transition temperature ABCDEFI FGI
2.12 1 Melt index ABCDEHI 1
T- I- I
ABCDEFI I I 1 FGi
2.13 1 Melting point I
ABCDEFHIJ 1 IJ
2.14 1 Hydraulic expansion IJ I
2.15 1 Biostability ABCDEFGHI
2.16 Film thickness J J J
2.17 % Elemental composition of a film
Surface physical properties
c.3.
ABDEJ I ABCDJ IABDJ 1
3.2 Critical surface tension
IJ
~ABCDJ TGDJ- I
3.3 Surface roughness ABDEJ
IJ
3.4 Surface chemical composition ABDEJ I ABCDJ IABDJ 1
IJ
t ARCD.1 I ARD.J I
Surface charge and charge density ABDEJ IJ
3.5
3.6 Surface resistance
i
c.4. Mechanical and chemical propertic
ABCDJ I ABDHJ IABDJ I
4.2 Wear resistance I
ABDE ABDH ABD
4.3 Coefficient of friction
4.4 Peel strength DE
4.5 Flexural strength BDE E ABD
ABCE
4.6 Compressive strength I IABD 1
I
4.7 Tensile strength DEI I ABCDE I ABCDEH IABD I
I ARCDFHJ I ARM I
4.8 Tensile strain to failure (elongation) DEIJ I ABCDE
4.9 Strain energy to failure
ABCDEH
4.10 Residual stress ABCDEFGH ABD
4.11 Stress relaxation ABCDEFGH ABCDE
4.12 ABCDEH
Creep
ABCDEH
4.13 Fracture toughness ABD
I
4.14 Crack growth velocity IABCDEH IABD I
I
4.15 Fatigue life ~ ABCDEHI I I ABCDEH IABD I
4.16
Stress corrosion potential I ABDH
4.17 Galvanic corrosion potential ABCDH
4.18 Fretting corrosion potential ABDH
4.19 Void concentration J J J
NOTE - See figure E.l and annex E for description of components A to J.
1) A Orifice ring (housing) D Occluder/leaflet G Sewing ring filler J Coating
B Occluder retention mechanism E Stent H Sewing ring retaining material
C Stiffening element F Covering I Component joining material
6
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0 IS0 IS0 5840: 1996(E)
Table 2 - Physical and chemical properties for application to design of heart valve substitutes
and their components
Appropriate for current
Physical and chemical properties tests
Calcification (in viva model)
5.52 Valve assembly testing
The physical and chemical properties relating to valve design, listed in table 2, shall be evaluated on heart valve
substitutes, subassemblies or components as applicable.
5.6 Test report
Each test report shall include:
rationale for the test;
a)
b) identity of the material tested (e.g. generic chemical name or biological source) or a description of the item(s)
tested;
identification of the sample tested (e.g. batch number);
c)
d) number of specimens tested;
e) test method used and, where a test method other than a test specified in an International Standard is used, full
details of the test procedure;
f) test results.
6 Hydrodynamic testing (see A.2 for rationale)
6.1 Principle
Hydrodynamic testing provides in vitro information on the fluid mechanical performance of the heart valve
substitute under steady and pulsatile flow conditions.
6.2 General
All heart valve substitutes to be tested shall be of quality suitable for human implantation. Before testing, each
heart valve substitute shall have been sterilized by the process used or intended to be used by the manufacturer
during production. If a heart valve substitute can be resterilized prior to implantation, it shall also be subjected to
the recommended maximum number of resterilization cycles, using the method stated by the manufacturer.
7
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IS0 5840:1996( E)
6.3 Steady forward-flow testing
6.3.1 Measuring equipment accuracy and testing fluid
6.3.1.1 The pressure measurement system shall have a measurement accuracy of at least k 0,13 kPa
(+ 1 mmHg).
6.3.1.2 All measuring equipment shall have a measurement accuracy of at least + 5 % of the full-scale reading.
6.3.1.3 The fluid used for the test shall be isotonic saline, blood or a blood-equivalent fluid whose physical
properties (e.g. specific gravity, viscosity at working temperature) shall be stated.
6.3.2 Test apparatus requirements
6.3.2.1 Steady-flow testing for aortic and mitral heart valve substitutes shall be conducted in a straight tube
having an internal diameter of 35 mm.
6.3.2.2 The test system shall be capable of generating flowrates of at least 30 I/min.
6.3.2.3 Flow entering the test chamber shall be relatively nondisturbed, which can be achieved with a flow
straightener upstream of the heart valve substitute.
6.3.2.4 Pressure taps shall be located one tube-diameter upstream and three tube-diameters downstream from
the midplane of the heart valve substitute sewing ring. If sufficient data can be provided to demonstrate
comparable results, other pressure tap configurations may be used.
6.3.2.5 The pressure taps shall be flush with the inner wall of the tube.
6.3.2.6 A standard nozzle in accordance with figure 3 a) shall be used to characterize the forward-flow pressure
and flow-measuring equipment.
6.3.3 Test procedure
6.3.3.1 Carry out the test on at least three heart valve substitutes of each tissue annulus diameter.
6.3.3.2 Measure the pressure difference across the test valve and the standard nozzle over a flowrate range of
5 I/min to 30 I/min, in 5 I/min increments.
6.3.4 Test report
The steady-flow test report shall include:
a description of the fl ui d used for the test, ncluding its biolog ical origin or chemical components, temperature,
a)
specific ravity under the test conditions;
viscosity and
g
a description of the steady-flow apparatus, as specified in 6.3.2.
b)
range and standard d eviation of th e followi rfo rmance test va ria ble simulated
Details of the mean, s, at each
Kl Pe
condition for each tes t heart valve substitut e and standar *d nozzle, shall be presented in ta bular or graphic form:
steady flowrate, expressed in litres per minute;
d
d) pressure differences, expressed in kilopascals and in millimetres mercury;
effective orif ice area, expressed in square centi metres, calculated taking into account the pressure recovery
e)
downstream fro m the test heart val ve subs titute
8
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IS0 5840: 1996(E)
Dimensions in millimetres
Surface roughners values in micrometres
8 +0,05
t
-=@--I
--m-------w----
In
0
d
tl
v3
-
In
Ftow
0
A
-
d
+I Flow
-_~- P _~_-
Ln m
Lh
L
0,s +0,05
I
---------------
Watt of vessel model
Watt of vessel model
a) Forward flow
b) Back flow
Standard nozzle
Figure 3 -
9
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IS0 5840: 1996(E)
EXAMPLE, based on the Carnot equation:
EOA= A-.
I+ 2AP
2
PV
d
where
EOA is the effective orifice area;
A is the cross-sectional area of the tube;
AP is the mean pressure difference across heart valve substitute;
V is the cross-sectional average velocity in the tube;
is the density of testing fluid.
P
6.4 Steady back-flow leakage testing
6.4.1 Measuring equipment accuracy and testing fluid
6.4.1.1 Regurgitant volume measurements shall have a measurement accuracy of at least rt 1 ml.
6.4.1.2 All measuring equipment shall have a measurement accuracy of at least & 5 % of the full-scale reading.
be isotonic saline, blood or a blood -equivalent fluid whose physical
6.4.1.3 The fluid used for the test shall
properties (e. g. specific gravity, v iscosity at wo rking tern perature) shall be s tated.
6.4.2 Test apparatus requirements
6.4.2.1 The steady back-flow leakage testing shall be conducted in an apparatus that is capable of generating
constant back-pressures in the range of 5,2 kPa to 26 kPa (40 mmHg to 200 mmHg).
6.4.2.2 The heart valve substitute shall be mounted in a manner to prevent leakage around and through the
sewing ring.
6.4.2.3 A standard nozzle in accordance with figure 3 b) shall be used to characterize the back-pressure, leakage
#ment.
volume flowrate and pressure-measunng
6.4.3 Test procedure
6.4.3.1 Carry out the test on at least three heart valve substitutes of each tissue annulus diameter.
6.4.3.2 Measure the static leakage across the test valve and the standard nozzle at five equidistant back-
pressures in the range of 5,2 kPa (40 mmHg) to 26 kPa (200 mmHg). Collect at least five measurements at each
condition.
6.4.4 Test report
The steady back-flow test report shall include:
a descriptio n of the flui d use d for the test, i ncluding its biological origin or chemical components, temperature,
VI under the test conditions;
scosity an d specific g ravity
a description of the steady flow apparatus, as specified in 6.42;
b)
c) details of the mean, range and standard deviation of the performance test variables, at each simulated
condition for each test heart valve substitute and standard nozzle, presented in tabular or graphic form; i.e.
static leakage volume flowrate, expressed in litres per minute, as a function of back-pressure, expressed in
kilopascals.
10
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@ IS0 IS0 5840: 1996(E)
6.5 Pulsatile-flow testing
Measuring equipment accuracy and testing fluids
6.5.1
6.5.1.1 The pressure measurement system shall have a natural frequency of at least 20 Hz and a measurement
accuracy of at least & 0,26 kPa (+ 2 mmHg).
6.5.1.2 Regurgitant volume measurements shall have a measurement accuracy of at least + 2 ml.
6.5.1.3 All measuring equipment other than that specified in 6.5.1 .I and 6.5.1.2 shall have a measurement
accuracy of at least + 5 % of the full-scale reading.
6.5.1.4 The fluid used for the test shall be isotonic saline, blood or a blood-equivalent fluid whose physical
properties (e.g. specific gravity, viscosity at working temperature) shall be stated.
6.5.2 Test apparatus requirements
6.5.2.1 The pulsatile-flow testing shall be conducted in a pulse duplicator which produces pressure and flow
waveforms that approximate physiological conditions (see
...
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