4. Catheter Selection
The initial left heart catheter in most cases is a
pigtail catheter with end- and multiple side holes .
This catheter usually can be flushed in the
descending aorta and then advanced to the
ascending aorta without difficulty.
dual-lumen pigtail - a specially designed pigtail
with a separate end-hole lumen and side-hole
lumen in patients with aortic stenosis.
straight dual-lumen catheter is used when
evaluating intraventricular gradients (as in the
cases o f hypertrophic cardiomyopathy) .
5. If LV and femoral arterial (sheath side arm)
pressures are being monitored (as in
catheterization to evaluate aortic stenosis) , the
rough equality of central aortic and femoral
arterial pressure should be confirmed at this
time.
For the highest-pressure fidelity, the sheath
size should be one F size larger than the
intended left heart catheter ( e . g . , a 5 F
pigtail advanced though a 6F sheath) .
6. Crossing the Aortic Valve
After measurement of the ascending aortic
pressure , the pigtail catheter is advanced
across the aortic valve and into the left
ventricle.
If the aortic valve is normal and the pigtail is
oriented correctly, it will usually cross the
valve directly.
In many cases , however, it may be necessary
to advance the pigtail down into one of the
sinuses Valsalva to form a secondary loop.
7.
8. If significant aortic stenosis is present, the
pigtail must be advanced across the valve
with the aid of a straight 0.038-inch
guidewire.
Approximately 6 cm of the guidewire is
advanced beyond the end of the pigtail
catheter, and the catheter is withdrawn slightly
until the tip of the guidewire is leading.
9.
10. The position of the tip of the guidewire within the
aortic root can then be controlled by rotation of
the pigtail catheter and adjustment of the
amount of wire that protrudes.
Wire and catheter are then advanced as a unit
until the wire crosses into the left ventricle.
11. If the wire buckles in the sinus of Valsalva
instead of crossing the valve, the catheter-wire
system is withdrawn slightly and readvanced .
Alternatively, some operators prefer to leave
the pigtail catheter fixed and move the
guidewire independently in attempts to cross
stenotic aortic valves.
In either case, the wire should be withdrawn
and cleaned and the catheter should be
double-flushed vigorously every 3 minutes
despite systemic heparinization.
12. If promising wire positions are not obtained, the
process should be repeated using a different
catheter: a left Amplatz (AL l ) catheter if the
aortic root is normal or dilated or a Judkins
right coronary catheter if the aortic root is
unusually narrow together with a straight wire
.
As of today, the left Amplaz (AL l ) catheter is
the preferred catheter by most operators to
cross a stenotic aortic valve.
13. When the tip of the guidewire is across the aortic
valve, additional wire should be inserted before
any attempt is made to advance the catheter
itself.
Otherwise the catheter may be diverted into a
sinus of Valsalva, causing the wire to flip out of the
left ventricle.
It is important to note that when crossing the
aortic valve with catheters other than the pigtail, a
left anterior oblique (LAO) or anteroposterior
view should be used in order to prevent
inadvertent advancement of the straight wire in
the coronary ostium.
14. Once the tip of the wire has crossed the valve,
the RAO angle should be used to visualize
the position of the wire .
Once the catheter is in the left ventricle, the
wire is immediately withdrawn and the
catheter is aspirated vigorously, flushed, and
hooked up for pressure monitoring .
15. When using a left Amplatz catheter to cross a
stenotic valve, it is better to cross the valve
with a full exchange length (260 em)
guidewire.
Once the tip of this wire has entered the left
ventricle, the Amplatz catheter is removed,
and a conventional dual-lumen pigtail catheter
is substituted before an attempt is made to
measure LV pressure.
16. Control of the Puncture Site
Following Sheath Removal
patients were usually taken to a special holding
room in the catheterization laboratory or back
to their hospital beds before the sheaths were
removed.
standard groin management required the effect
of heparin to wear off or be reversed by
protamine to an ACT < 1 6 0 seconds before
the arterial catheter and sheath were removed.
Manual pressure method is applied using three
fingers of the left hand that are positioned
sequentially up the femoral artery beginning at
the skin puncture.
17. apply sufficient pressure to obliterate the pedal
pulses and then release just enough pressure
to allow them to barely return.
gradually reduced the pressure over the next
10 to 15 minutes and then remove the pressure
completely.
The venous sheath is usually removed 5
minutes after compression of the arterial
puncture has begun, with gentle pressure
applied over the venous puncture using the
right hand.
18. If larger arterial sheaths or thrombolytic
agents are used, more prolonged (30- to 45 -
min) compression is required .
Sometimes a mechanical device (
Compressar , The Clamp Ease device or
FemoStop ) can be used to apply similar local
pressure to avoid fatigue of the operator or
other laboratory personnel.
19. After compression has been completed, the
puncture site and surrounding area are
inspected for hematoma formation and active
oozing, and the quality of the distal pulse is
assessed before application of a bandage.
The patient is usually kept at bed rest with the
leg straight for 4 to 6 hours following a
diagnostic percutaneous femoral catheterization.
The use of a sandbag over the puncture site for
the first few hours after catheter removal is no
longer routine since it has not been shown to
decrease the incidence of hematoma formation.
20. In patients at higher risk for rebleeding (those
with hypertension, obesity, or aortic regurgitation) ,
application of a pressure bandage together with
a sandbag may be of some value .
Elevation of the head and chest to 30° to 45° by
the electrical or manual bed control – for
patient's comfort and it will not increase the risk of
local bleeding.
Before ambulation and again before discharge, the
puncture site should be reinspected for recurrent
bleeding, hematoma formation, development of a
bruit suggestive of pseudoaneurysm or A-V fistula
formation, or loss of distal pulses.
21. Contraindications to Femoral
Approach to Left Heart Catheterization
There are relatively few patients who absolutely
cannot be catheterized from the femoral approach.
Difficulty in catheter insertion and manipulation -
peripheral vascular disease (femoral bruits or
diminished lower extremity pulses) , abdominal
aortic aneurysm, marked iliac tortuosity, prior
femoral arterial graft surgery, or gross obesity,
Problems with bleeding - patients with a wide
pulse pressure (e.g. , severe aortic incompetence or
systemic hypertension) , gross obesity, or ongoing
anticoagulation.
22. Alternative sites for left
heart catheterization
percutaneous insertion of a catheter from the
axillary, brachial , or radial arteries , or even the
lumbar aorta , with the use of an introducing
sheath.
transseptal puncture from the right atrium to the
left atrium
direct percutaneous entry via the left ventricular
apex.
23. Transseptal Puncture
Indications -
If direct left atrial pressure recording is desired
(pulmonary venous disease) ,
To distinguish true idiopathic hypertrophic
subaortic stenosis from catheter entrapment,
If retrograde left-sided heart catheterization had
failed (e.g. , owing to severe peripheral arterial
disease or aortic stenosis) or was dangerous
owing to the presence of a certain type of
mechanical prosthetic valve.
24. The goal of transseptal catheterization is to
cross from the right atrium to the left atrium
through the fossa ovalis .
In approximately 10% of patients , this
maneuver is performed inadvertently during
right heart catheterization with a woven
Dacron catheter because of the presence of a
probe-patent foramen ovale , but in the
remainder, mechanical puncture of this area
with a needle and catheter combination is
required to enter the left atrium.
25. Classically, transseptal catheterization is
performed from the right femoral vein , although
transjugular or left femoral vein approach is
feasible but more complicated. For the right
femoral approach we use a 71 -cm curved
Brockenbrough needle, which tapers from 18-
gauge to 21 -gauge at the tip .
The needle is introduced via a matching
Brockenbrough catheter or 8F Mullins
sheath and dilator combination; that has been
inserted into the superior vena cava over a
flexible 0.032-inch, 145-cm ] guidewire.
26. If the foramen is patent, the catheter may actually
cross into the left atrium spontaneously at this point,
as indicated by a change in atrial pressure
waveform and the ability to withdraw oxygenated
blood from the needle .
Otherwise, the catheter is advanced slightly to flex
its tip against the limbus at the superior portion
of the foramen ovale. Once the operator is
satisfied with this position, she or he advances the
Brockenbrough needle smartly so that its point
emerges from the tip of the catheter and perforates
the atrial septum .
When the catheter is across the atrial septum, the
needle is withdrawn and the catheter is double-
flushed vigorously and connected to a manifold
for pressure recording.
27. As the catheter tip moves anteriorly and
downward, further advancement will usually
allow it to cross the mitral valve and enter the
left ventricle .
Complications of transseptal catheterization
for diagnostic purposes are generally infrequent
-
needle tip perforation < 1 % ,
tamponade < 1 % , and
death < 0 . 5% in experienced hands.
28. Hemodynamic data
Pressure measurements
Measurement of flow (eg: cardiac
output,shunt flow,flow across a stenotic
orifice,regurgitant flow,and coronary blood
flow)
Determination of vascular resistance.
31. Example of PCWP tracing, reflecting the LA
pressure, in a normal person.
32. Pulmonary Capillary Wedge and Left
Atrium
The PCWP is an occluded pressure reflecting
downstream LA pressure provided that there is
proper positioning, and there are no intervening
anatomic obstructions (e.g. pulmonary venous
obstruction, cor tritriatum).
There is a time delay between the PCWP and the
LA tracings of about 140 to 200 msec.
The PCW and LA pressure tracings are again
characterized by a, c, and v waves. However
when compared to the RA pressure tracing, the
LA pressure pulse exhibits a normally dominant v
wave (<15 mmHg) and a subordinate a wave
(<12 mmHg)
33. The left atrial v wave is usually higher than the a wave,
and neither is >5 mm Hg above the mean pressure.
Elevated a wave -
left atrial outflow obstruction
mitral stenosis,
supravalvar mitral ring
diseases that impair left ventricular compliance
aortic stenosis,
coarctation of the aorta.
The a wave may be dominant with an atrial septal
defect, as a large atrial septal defect allows
transmission of pressure across the septum, or with
diseases that elevate the right atrial a wave.
34. Elevated v waves
mitral regurgitation.
Elevation of the left atrial mean pressure (and
both the a and v waves)
large left-to-right shunts at the ventricular or great
vessel level
sign of left ventricular failure.
35. LV and LA pressure tracings in isolated,
sever MR and atrial fibrillation. The a and c
waves in the LA tracing are not evident and
the v wave is accentuated
37. End-diastolic pressure
The location on the atrial pressure wave that best
reflects end-diastolic pressure is the point just prior
to the “C” wave .
38. If the Pre C wave point is not available, a second
method for identification of the end-diastolic
pressure is to take the mean of the highest and
lowest “a” wave pressure
39. The end-diastolic pressure can be estimated by
identifying the “Z” point.
Draw a line from the end of the QRS to the atrial
tracing. The point where the line intersects with the
waveform is the “Z” line
40. The LVEDP immediately precedes the
beginning of isovolumetric contraction in the
LV pressure pulse.
In general, the mean PCWP, mean LAP, and
LVEDP are all near equivalent in magnitude.
41.
42.
43. The LVEDP is elevated (>12 mmHg) in:
1) LV diastolic volume overload (e.g. MR, AR, a large
left-to right shunt)
2) Concentric hypertrophy (decreased compliance)
e.g. AS or long-standing HTN
3) Decreased myocardial contractility (dilated LV)
4) Restrictive or infiltrative cardiomyopathy
5) Constrictive pericardial disease (or a high
pressure pericardial effusion)
6) Ischemic heart disease. (Acute or chronic
secondary to noncompliance, scar)
44.
45. If the end-diastolic pressures in the left atrium
and left ventricle are not equal, some form of
mitral valve obstruction is present.
Higher gradients (>8 to 10 mm Hg) suggest
structural mitral stenosis, whereas lower
gradients suggest physiologic stenosis due to
increased blood flow across the valve, such as
from a large ventricular septal defect.
46. LA and LV pressure tracings in a patient with
MS. Shaded area represents the mitral valve
gradient. DFP= diastolic filling period.
49. The peak systolic pressure in the left ventricle
should be equal to or up to 5 mm Hg greater
than the peak systolic pressure in the
ascending aorta.
A gradient between the left ventricle and the
aorta is present in dynamic left ventricular
obstruction (as in hypertrophic
cardiomyopathy), subaortic stenosis, or
aortic valve stenosis.
51. C: Pressure
pullback
recording in a
patient with
subvalvar
aortic stenosis
D: Pressure
pullback
recording in a
patient with
supravalvar
aortic
stenosis
52. Ascending aorta
During ejection normal pressure in the ascending
aorta parallels LV pressure.
Once the AV closes the aortic pressure declines
somewhat slower than the LV pressure. This reflects
the accumulated pressure waves from thoracic aorta
and its tributaries as well as the capacitance of the
aorta.
Following the dicrotic notch, there is a brief increase
in pressure due to some retrograde flow from the
periphery into the ascending aorta and the elastic
recoil of ascending aorta.
Then as the blood runs off into the periphery, there is
a gradual decline in the systolic arterial pressure until
the next cardiac cycle.
53. C: Aorta (each
horizontal line =
10 mm Hg): 98/50.
54. The rate and magnitude of decline of aortic
pressure during diastole are dependent on:
1) Aortic valve integrity (eg aortic insufiiciency)
2) Capacitance and resistance of the peripheral
circuit
3) Presence or absence of abnormal connection of
aorta and the pulmonary circulation or the right
heart (e.g. PDA)
4) Presence or the absence of a large
arteriovenous fistula
55. Combined MS and MR
Combined MS and MR is often associated with a
heavily calcified valve that has limited leaflet
mobility.
Because systolic regurgitation augments
antegrade flow during the subsequent diastole, a
transvalvular pressure gradient can develop in
patients with a relatively mild compromise of the
mitral orifice area (approximately 2.0 cm2).
Significant dilatation of LA is seen owing to the
combined pressure and volume overload of the
chamber.
56. In this setting, the pressure recordings from the
left heart reveal an early and mid-diastolic
pressure gradient across the MV, but if the DFP
is sufficiently long, the LA and LV pressures
equilibrate during the period of slow ventricular
filling .
The v wave is often dominant, reflecting the
augmented systolic expansion and dilatation of
LA.
57. PCW and LV pressure tracings in a patient
with combined MS/MR in atrial fibrillation.
59. Measurement of cardiac output, in terms of
pulmonary and systemic blood flow, is a
necessary first step to quantifying shunt
volume and vascular resistance.
Because cardiac output cannot be measured
directly, it can be estimated using the indicator
dilution technique described by Fick .
The indicators most commonly used are
oxygen or cold saline (thermodilution).
60. Hemodynamic Equations
The term oxygen capacity refers to the amount
of oxygen that can be bound by fully saturated
hemoglobin in
blood; maximum oxygen capacity is 1.36 mL O2
per 1 g of hemoglobin.
61. Dissolved oxygen in plasma is determined by the
solubility coefficient of oxygen, temperature, and
the pO2. At
37°C (body temperature), the amount of oxygen
dissolved in blood is 0.003 mL O2/mm Hg
O2/dL blood.
The total oxygen content in a sample of blood is
the sum of dissolved oxygen in the blood and the
oxygen that is bound to hemoglobin:
62. Oxygen Method for Calculation of
Cardiac Output
When cardiac output is calculated using the
Fick method, the indicator is oxygen.
The rate of change of the indicator is the
oxygen consumption (VO2). Assuming that
measurements are taken at a steady-state
condition, oxygen consumption by tissues
equals oxygen uptake by the lungs. VO2 may
be measured or assumed.
Assumed values that are most often used for
calculations are based on the formulas of
Lafarge and Meittinen.
63.
64.
65. The systemic flow (QS) is equal to the VO2
divided by the change in oxygen content across
the body (oxygen content of the aorta minus the
SVC).
If the patient is breathing room air, the amount of
dissolved oxygen can be ignored, simplifying the
equation to:
66. Similarly, the pulmonary flow (QP) is equal to the
VO2 divided by the change in oxygen content
across the lungs (oxygen content of the
pulmonary vein minus oxygen content of the
pulmonary artery).
And if ignoring dissolved oxygen:
67. Thermodilution Method
With the thermodilution method, the indicator is
temperature.
A double-lumen thermodilution (Swan-Ganz)
catheter is used.
A bolus of cold saline of a known temperature
(room temperature, ∼21°C) is injected through
the proximal port (positioned in the right
atrium).
A thermistor for measuring temperature is
located near the catheter tip (positioned in the
pulmonary artery).
68. Saline cools the blood as they mix together - the
degree of cooling of the blood is inversely
proportional to the magnitude of flow and directly
proportional to several known, assumed, or
measured factors:
the volume of saline injected,
the temperature difference between the injectate
and the blood,
the specific heats of the injectate and the blood.
The thermodilution cardiac output measurement is
an automated system (including the injector) and the
calculations are performed by a computer.
69. Quantitative Assessment of
Shunts
Calculation of left-to-right and right-to-left shunts
requires understanding the concept of effective
pulmonary flow (QEP) and effective systemic
flow (QES).
The QEP is the volume of systemic venous
return (i.e., “blue” blood) that flows to the
lungs to be oxygenated.
QEP is calculated by using the oxygen saturation
of the “red” blood flowing out of the lungs
(pulmonary vein) minus the saturation of the “blue”
blood flowing into the lungs (SVC) as shown in the
following equation:
70. Therefore, if the patient has no left-to-right shunt,
the mixed venous saturation and pulmonary artery
saturation are the same, and all of the pulmonary
blood flow is “effective,” that is QP = QEP.
The QES is the volume of pulmonary venous
return (i.e., “red” blood) that flows to the body.
For all patients in a steady hemodynamic state:
Simply stated, the amount of “blue” blood that flows
to the lungs is equal to the amount of “red” blood
that flows to the body.
71. When there is a left-to-right shunt, some
oxygenated blood recirculates through the lungs,
thus QP > QEP. The volume of a left-to-right shunt
is the difference between the total pulmonary flow
(QP) and the effective pulmonary flow (QEP):
Similarly, when there is a right-to-left shunt, some
of the deoxygenated “blue” blood bypasses the
lungs and recirculates through the body, thus QS >
QES. The volume of a right-to-left shunt is the
difference between the total systemic flow (QS)
and the effective systemic flow (QES):
72. Since QEP = QES, then:
Mathematically, the ratio of pulmonary flow to
systemic flow is QP/QS.
73. If the patient is breathing room air, dissolved
oxygen is negligible, and the calculation of
QP/QS can be approximated in terms of
oxygen saturation samples as follows:
74. Qualitative Assessment of
Shunts
Qualitatively, if there is a step-up in oxygen saturations
in the right heart, there is a left-to-right shunt.
Conversely, there is a right-to-left shunt if there is a
step-down in oxygen saturations in the left heart.
High mid-SVC saturation
a high-output state,
partial or total anomalous pulmonary venous return to
the SVC or innominate vein,
an arteriovenous fistula.
Low mid-SVC saturation
when the systemic arterial saturation is low (pulmonary
venous desaturation, right-to-left shunt)
low cardiac output state (high tissue extraction).
75. Right atrial sample
A step-up of >9% is highly suggestive of a left-to-
right shunt from an
atrial septal defect,
anomalous pulmonary venous connection,
left ventricle-to-right atrium shunt,
ventricular septal defect with tricuspid insufficiency,
a shunt from the aorta (ruptured sinus of Valsalva
aneurysm, coronary artery fistula).
However, the absence of a significant step-up
in the right atrium does not completely rule out
a left-to-right shunt.
76. Right ventricular saturation
A step-up of >6% suggests a left-to-right shunt
from
low atrial septal defect (where the oxygenated
blood preferentially streams into the right
ventricle),
ventricular septal defect,
ruptured sinus of Valsalva aneurysm,
coronary AV fistula draining into the right
ventricle,
left-to-right shunt at the great vessel level with
significant pulmonary valve insufficiency.
77. Pulmonary artery
A step-up of >6% at the pulmonary artery level is
seen with
high outlet ventricular septal defect,
patent ductus arteriosus,
aortopulmonary window,
coronary artery fistula into the pulmonary artery,
anomalous origin of the coronary artery from the
pulmonary artery also with fistula,
surgical aortopulmonary communication.
78. Right-to-left shunt
If the aortic saturation is <92% (sea level,
normal ventilation) or if there is >3% decrease
in oxygen saturation on the left side of the
heart, a right-to-left shunt is likely present.
79. Left atrial desaturation, with normal pulmonary
vein saturation (right-to-left shunt) through an
atrial septal defect or PFO.
tricuspid atresia (a necessary shunt )
tricuspid stenosis,
Ebstein anomaly of the tricuspid valve,
pulmonary atresia or severe pulmonic stenosis,
severe pulmonary vascular disease.
any disease that markedly decreases right
ventricular compliance or leads to right
ventricular failure
80. platypnea-orthodeoxia syndrome, produces
cyanosis and dyspnea, which is due to
cyanosis from right-toleft shunting across a
PFO as one changes position from supine to
sitting.
a persistent left SVC to the left atrium, also
can cause left atrial desaturation.
81. Left ventricular desaturation
when the right ventricular systolic pressure is
equal to or greater than left ventricular systolic
pressure (e.g., a ventricular septal defect and
elevated pulmonary vascular resistance or right
ventricular outflow tract obstruction).
Right-to-left shunting can occur during diastole if
the right ventricular diastolic pressure exceeds
that of the left ventricle,
tetralogy of Fallot
82. A decrease in oxygen saturation between the
left ventricle and aorta
patent ductus arteriosus or aortopulmonary window,
combined with either pulmonary vascular
obstructive disease or peripheral pulmonary
stenosis.
A decrease in saturation from the ascending to
the descending aorta
combination of a patent ductus arteriosus and
coarctation of the aorta
83. Vascular Resistance
The basic formula for vascular resistance shows us
that resistance is related to the pressure drop across
the vascular bed divided by the flow across the
vascular bed.
Mathematical assessment of vascular resistance is
based on laws of Poiseuille and Ohm (which
describe electrical resistance). simplified equation for
calculation of vascular resistance ( R):
where
ΔP = change in pressure across the vascular bed
Q = flow in the vascular bed
84. The pulmonary vascular resistance (Rp) equation is
where Δ pulmonary pressure is the change in
pressure across the pulmonary vascular bed (i.e.,
pulmonary artery mean pressure – left atrial
mean pressure), often called the transpulmonary
gradient.
Similarly, the equation for systemic vascular
resistance is:
where Δ systemic pressure is the change in
pressure across the systemic vascular bed (i.e.,
systemic arterial mean pressure – right atrial
85. When assessing the pulmonary vascular reactivity
to various medications, a drop in pulmonary
pressure may be related to the medicine decreasing
the systemic resistance.
In such situations, calculating the relative
resistances of the pulmonary and systemic
vasculature may provide useful information:
This “hybrid” vascular resistance unit, the Wood unit,
is defined in mm Hg/L/min; it is used for pediatric
hemodynamic calculations
The normal range for indexed pulmonary resistance
is 1 to 3 Wood units·m2.
The normal range for indexed systemic resistance is
20 to 28 Wood units·m2.
86. Angiographic Views
Left ventriculography
RAO 30 - Anterior ,apical and inferior walls.
LAO 60 and Cranial 20- lateral and septal
ventricular walls. • Suspected VSD,MR.
Aortography
LAO view – Ascending aorta, Aortic arch,
innominate, carotids,left subclavian arteries.
RAO view – lower thoracic aorta, assessing AR.
The descending aorta and ascending aorta are
superimposed across the arch in AP projection.
87. Power injection of 30-40ml of contrast
medium into the left ventricle at 12-15ml/sec
is used to assess LV function and the severity
of MR.