Transcript Pulmonary blood flow - Society for Cardiovascular Angiography and

Catheter Based Treatment of
Adult Congenital Heart
Disease
Zoltan G. Turi, M.D.
Robert Wood Johnson Medical School
August 21, 2004
[email protected]
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Scope of the Problem
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> 500,000 patients with adult congenital heart
disease in the US
0.8 % of live births, not including bicuspid
aortic valves (1-2%), MVP (3-7%)
Burgeoning technologies
–
Limit discussion to approved devices, techniques
–
Limit discussion to relatively common structural
abnormalities – not complex post repair states
Diseases in Adult Congenital
Heart Disease Intervention
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All are lesions that typically allow survival to adulthood
without intervention
Stenoses
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Pulmonic
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Valvar
Branch
Congenital aortic – juvenile bicuspid A.S.
Coarctation
Fenestrations
Patent Foramen Ovale *
– Atrial Septal Defect
– Patent Ductus Arteriosus*
– Ventricular Septal Defects
* Account for 93% of systemic circulation in utero
–
Cardiac Cath in Congenital Heart Disease
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Paradox - Need to know anatomy to do cath
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Cardiac output and shunt calculations essential
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Need to appreciate pitfalls of oxygen consumption
measurement
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PVR and SVR importance
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Need to understand basics of shunting
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Need to appreciate basics of mixed venous oxygen
saturation
Oxygen mixing
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Right atrial oxygen saturation is highest in:
1.
Coronary sinus
2.
Inferior vena cava
3.
Superior vena cava
4.
Left superior vena cava
Normal maximum “step-ups” between sites
–
SVC-PA 7%
–
SVC-RA 11%
–
RV-PA 5%
Mixed venous = (3*SVC+IVC)/4
Fick principle
• As applied to any
vascular bed, the
difference in oxygen
content across that bed
divided into the oxygen
consumed.
• In the setting of a shunt,
compare flows across
individual beds
Fast train = little change
in concentration
Slow train = maximal
extraction and greatest
delta
But it all depends on
oxygen consumption !!!
J. Grossman
Quick and dirty:
Large difference in PA and Systemic saturations:
Low cardiac output – train moves slowly – greater extraction
Low oxygen carrying capacity – need to extract maximum
oxygen
because of low hemoglobin
Oxygen consumption and Cardiac Output
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O2 onsumption rarely measured directly
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Typically assumed to be 125 ml/min/m2
Accurate ± 10 - 30%
–
Decreased in low output state, somnolence,
hypothyroidism, etc.
–
Increased in high output state, undersedation,
hyperthyroidism, etc.
Cardiac output (as typically measured) =
O2 consumption/ (FA - PA) O2 content * 10 - assumes
that pulmonary and systemic flows are equal, PV=FA,
and mixed venous (MV) = PA sat
Shunts
●
Shunt ratio –
AO - MV = Pulmonary blood flow
PV - PA
Systemic blood flow
Typically assumed FA = Ao saturation and no right to left;
if right to left with ASD or VSD, Ao lower than PV. In
ductus with right to left, FA will be lower than Ao.
–
Ao = 95%; PA = 80%; SVC = 62%; IVC = 70%
MV = (3*62 + 70)/4 = 64
Shunt = (95-64)/(95-80) = 31/15 ~ 2:1
Resistance
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Ohm’s Law
Voltage drop = flow * resistance
Resistance =
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Voltage
Flow
As applied in vascular physiology:
Resistance = Pressure drop across a vascular bed
Flow across vascular bed
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As applied to pulmonary hemodynamics:
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PVR = Mean PA – Mean PAW pressure
Pulmonary blood flow
As applied to pulmonary hemodynamics:
SVR = Mean PA – Mean PAW pressure
Systemic blood flow
Resistance = Wood units. Multiply by 80 for dynes-sec-cm-5
Pulmonary Hypertension
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Variable definitions but typically:
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mPA < 20 = nl, 20 – 30 = mild, >30 = mod, > 45 = severe
Nl PVR = 1- 3 Wood or 80 -240 dynes-sec-cm-5
Nl SVR = approximately 10 x nl PVR
PVR/SVR > 0.5 to 0..75 suggests high risk or inoperable
patient
Vasodilator challenge with nitric oxide, adenosine,
oxygen, dihydropyridines, prostacycline, etc. to assess
reversibility
Pulmonic Stenosis
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Adults develop RVH and eventual RV failure
Typically occurs in combination with other congenital
lesions
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Tetralogy of Fallot
Symptoms
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Fatigue
Dyspnea
Right heart failure
Syncope
Exertional angina
Pulmonic Valvuloplasty
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Indications:
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Patients with exertional angina, dyspnea,
syncope, or pre-syncope where the cause is
likely to be PS (e.g. young adults)
Asymptomatic patients with normal CO,
and gradient > 50 mm Hg Class I; 30 – 50
mm Hg Class II
Goal is gradient < 30 mm Hg; Excellent
20 to 30 year results
90 % success
Typically use 1 -2 balloons; oversize 20
- 40%
Kothari S
Pulmonic Valvuloplasty
• Suicide ventricle
– Typically chronic severe PS
– Infundibular hypertrophy
– Treat with beta blockade
• Surgery for dysplastic valves
(Noonan’s syndrome)
• Resultant mild or moderate
PI well tolerated
– RV handles volume overload
well
Pulmonary Branch Stenosis
• May be complication of maternal rubella,
William’s, Noonan’s, arteritis, external
compression
• Associated congenital abnormalities
• Typically at origins of main PA branches
– May occur at site of prior surgery e.g.
Blalock-Taussig
• Untreated: lung hypoperfusion/ dyspnea,
cyanosis, RV hypertension and failure
• Balloon alone – poor results
– PA segments too elastic → recoil
• Stenting generally successful – risks:
– Rupture
– Issue of patient growth in children
– Pulmonary hyperperfusion – edema,
hemoptysis
Indian Pediatrics
Congenital Aortic Stenosis
• Unicuspid valve – rare
– requires surgery
• Bicuspid – 1 – 2 %;
variable course; AR; L
dominant; familial
clusters.
– Associated with coarcts,
Williams Syndrome,
PDA, cystic medial
necrosis, Turner’s
Syndrome (30%
bicuspid)
– May have ejection click
– Echo : doming
Yale
Congenital Aortic Stenosis
LV dP/dt
300
200
Ao dP/dt
100
0
Congenital Aortic Stenosis-Treatment
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Antibiotic prophylaxis
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PBAV generally successful
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Young adults (and neonates)
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Indication = gradient > 50 mm Hg regardless of symptoms
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Balloon is procedure of choice for congenital AS
Complications of PBAV
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5% severe AR – most common with unicuspid valve
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Death, blood loss, perforation – 1-2%
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Success rates, restenosis, complications similar to surgery
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Will eventually need AVR, but when root is bigger
Coarctation of the Aorta
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Hypertension
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Claudication
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Renal hypoperfusion
Renal failure
 ABI’s
No PVD
Brachial-femoral lag
Syncope
> 50% have bicuspid aortic
valves
VSD, PDA, sub-Ao membrane,
parachute mitral, supra-mitral
ring associated
Occasional similar syndrome 2
trauma
o
Diagnosis
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Hypertension with or without murmur
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Murmur may disappear because of collaterals
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Murmur may be continuous because of collaterals
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Murmur of associated AS with or without ejection click
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Headaches, chest pain, intracranial hemorrhage
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Claudication only occasionally
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Left arm pressure may be lower if subclavian involved
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Suprasternal notch pulsation
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EKG - LVH
Radiographic Findings
UW
Considerations for Intervention
in Coarctation
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Hypertension
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Significant afterload on LV → wall stress → LVH
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Ameliorated by development of collaterals
Exacerbates L → R shunt with associated VSD, PDA
avoid ACE inhibitors → renal failure
Successful ↓ upper body BP may cause
hypoperfusion
Baroreceptors/renin-angiotensin system may not
reset
Planned pregnancy
Recurrent coarctation post repair – balloon
preferable; no concensus on native coarcts
Gradient > 20 mm Hg
Coarctation Angioplasty
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Balloon –
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80-90% success (<10 mm Hg gradient)
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do not oversize  rupture
Complications
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Rupture
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False aneurysm
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Aneurysm in 5%
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Higher rate of recurrence than surgery
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Paraplegia
Antibiotic prophylaxis indefinitely
Yale
Stenting for Coarctation
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Controlled tear
Perhaps superior
results
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Dissection and
aneurysm
formation less
likely
Yale
Atrial Septal Defect
30% of all congenital heart abnormalities in adults
Presenting symptoms – atrial arrhythmias, stroke/TIA,
fatigue,  exercise
Frequently asymptomatic first 3 decades – 70% symptomatic
by age 50
Ostium Primum
Yale Congenital Heart Disease
70%
ASD diagnosis
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2:1 female
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Yale
EKG – iRB3 in 90%
CX Ray –  pulm
vasculature, RA,LA
Physical
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MVP
MS = Lutembacher
Pulmonic flow
murmur; diastolic
rumble
Wide split S2
RV lift
Echo
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RV size and function
Shunting
UMN
Percutaneous Closure
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Indicated for:
Secundum ASD (or
Fontan)
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> 1.5:1 shunt (at a
minimum must have left
to right shunt) or
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Shunt ↓with ↑PVR
RVVO
Contraindications
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> 38-40 mm
A-V valve proximity
± Absence of rim (< 5
mm)
Children’s Memorial Chicago
Post ASD closure
• Medication
– Antibiotic prophylaxis x 6 months (none
required for untreated ASD’s)
– Aspirin and ? clopidogrel x 6 months or
anticoagulation
• Complications
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–
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Device embolization
Atrial arrhythmias
Clot formation on device
Pericardial effusion, TIA, sudden death
Residual flow through shunt
Mechanical interference with adjacent
structures
ASD – Percutaneous Closure
versus Surgery
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Surgery highly effective, low morbidity and
mortality in young patients
Major and minor adverse events rates with
surgery in 5 – 20% range
Major and minor adverse event rates with
percutaneous approach in 2 – 5% range
To prevent device erosion, guidelines for sizing
to unstretched orifice size – lowest size that
eliminates flow; avoid overriding aorta
Patent ductus
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Exercise
intolerance
Angina
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Coronary steal in
diastole
Endocarditis
1/3rd die by age of
40 of PHT, CHF if
no Rx.
Small PDAs with
benign course
Yale Congenital Heart Disease
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Machinery/continuous
murmur
CX-Ray prominent
pulmonary arteries;
biventricular
enlargement.
PDA
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Indication
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Left to right shunt
Endocarditis
prevention
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Beak shaped – coils
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1 loop PA – rest Ao
> 6 mm  occluder
Not severe PHT with
cyanosis
Success > 90%
PFO Anatomy
Photo from Textbook & Atlas of the
Cardiovascular System, Thomas, et
al.
Lurking Clot Theory
Cul de sac
Valsalva induced paradoxical flow results in embolic event.
• 36 year old ♀ 3 wks
dyspnea/syncope
• Left leg pain
• DVT
• Occluded left
popliteal
• PA systolic 80
mm Hg
• Multiple pe’s
Kessel-Schaefer Circulation 2001
Incidence of PFO in Patients
with and without ischemic stroke
50
40
Incidence
of PFO
(%)
40
P < 0.001
30
20
10
10
0
CVA
No CVA
n = 60
n = 100
Lechat et al. NEJM 1988:318;1148
Patients with CVA
60
50
Incidence
of PFO
(%)
54
40
40
30
20
21
10
0
Identifiable
cause
Risk factor
only
No identifiable
cause
n = 19
n = 15
n = 26
Lechat et al. NEJM 1988:318;1148
Recurrent Ischemic Events in Patients with
Cryptogenic Stroke and PFO
20
19
Number of
CVA/TIA
15
10
5
0
0
Antiplatelet/
Anticoagulant
Surgical
Closure
Cujec et al. Canadian J. Cardiology 1999:15;57
N = 581
Mas NEJM 2001
Rx Aspirin 300 mg
Indications
• PFO with right to left
shunting demonstrable
– Bubble study with
valsalva on TEE
– TCD
and
• Atrial Septal Aneurysm
and
• Recurrent
cerebrovascular events
despite anticoagulation
and
• No other etiology
TIA/stroke
Possible Indications
Unlikely to be Included
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Scuba divers
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Migraine headaches
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Need for transvenous pacemaker
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Platypnea-orthodeoxia
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Pulmonary hypertension with right to left shunt usually
not an indication
Ventricular Septal Defects
• Perimembranous
– Most common
– Located under tricuspid and
aortic valves
– Frequently close in
childhood
– Device closure experimental
– asymmetric to prevent
impingement on valves
• Muscular
– Typically at apex or along
muscular upper septum
– Most lends itself to
percutaneous closure
– CardioSeal approved
• Supracristal
– Between aortic and
pulmonic valves
P.Lynch Yale
VSD – size and shunting
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Shunt ratio depends on size of defect and resistance in
pulmonary bed
Small (restrictive) ,< 0.5 cm → < 1.5 : 1 shunt. 30 – 50%
close spontaneously in childhood.
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With large VSD, flow determined by ratio of PVR to SVR.
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High risk endocarditis
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Indications:
–
symptomatic, Qp:Qs > 1.5:1, PA systolic pressure > 50 mm Hg,
↓’ing LV function, non-Eisenmenger’s physiology
Question 1
A 50 year old patient with dyspnea is referred to you
because of a "heart murmur". Workup reveals gradient
across the pulmonic valve and clinical picture as
described. Which one would be the best candidate for
balloon pulmonary valvuloplasty?
a. A 30 mm Hg gradient across the pulmonic valve. The
patient has chronic lung disease.
b. An 80 mm Hg gradient across the pulmonic valve. The
valve appears dysplastic by echo.
c. A 70 mm Hg gradient across the pulmonic valve. The
patient has significant findings for right heart failure.
d. A 60 mm Hg gradient across the pulmonic valve. The
patient has severe bronchospasm and infundibular
hypertrophy.
Question 2
a.
b.
c.
d.
e.
A 34 year old woman has a single transient ischemic
attack. Extensive neurological workup reveals
predisposing factors listed below. Which of the
following scenarios would represent indication for
percutaneous closure of the PFO?
PFO, no atrial septal aneurysm, Protein C deficiency.
PFO, atrial septal aneurysm, normal coagulation workup.
PFO, no atrial septal aneurysm, normal coagulation
workup.
PFO, atrial septal aneurysm, migraine headaches.
None of the above.
for the non-surgical closure of a patent foramen ovale
(PFO) in patients with recurrent cryptogenic stroke(1) due
to presumed paradoxical embolism through a patent
foramen ovale and who have failed conventional drug
therapy(2).
(1) Cryptogenic stroke - a stroke occurring in the absence
of potential phanerogenic cardiac, pulmonary, vascular or
neurological sources. (2) Conventional drug therapy - a
therapeutic international normalized ratio (INR) on oral
anticoagulants
Phanerogenic – “denoting a disease the etiology of which is
manifest”
Question 3
A patient with chronic severe pulmonary hypertension has borderline
systemic pressures and persistent systemic desaturation. Noninvasive
studies demonstrate right to left shunting across the interatrial
septum. You are asked to intervene. You:
a. Size the fenestration, determine that there is an ASD and deploy an
ASD closure device.
b. Defer intervention of any kind.
c. In case the fenestration is a PFO, you bring the patient to the cardiac
cath lab and examine the effect of oxygen and nitric oxide on
hemodynamics.
d. Recommend surgical rather than percutaneous closure of an ASD.
Question 4
Which one of the following is false?
a. Mean survival of untreated coarct patients is age 35
b. A patient with coarctation should typically have a gradient of
at least 20 mm Hg before consideration of balloon dilatation
c. Antibiotic prophylaxis is not required.
d. Acute results of balloon dilatation for native and recurrent
coarctation are similar.
e. Long term results may include higher rate of aneurysm
formation post balloon dilatation of native coarcts compared
with surgery.
f. Cystic medical necrosis is common and frequently severe in
coarctation patients.
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“In adults with (de novo) coarctation, surgical repair can be achieved
with zero percent mortality.”
–
Actually, operative mortality ↑ because of degenerative aortic wall changes,
coexist bicuspid aortic valve, CAD, end organ damage from hypertension.
–
Complications of surgery – paradoxical hypertension, recurrent laryngeal
nerve paralysis, phrenic nerve injury, spinal paralysis.
“The application of this technique (balloon) for native coarctation is
somewhat controversial due to the high incidence (5-10%) of
recurrent coarctation and aneurysm formation”
Aneurysm in adults after balloon – 49 pts, mean age 22, f/u 10 yrs –
7.5%.
Aneurysm is uncommon (3%) with end-to-end repair.