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patients with untreated PAVM is 11%.44,47
one local anesthetic is superior to another, although one report
described the successful use of 0.75% ropivacaine in this setting,
citing the potential advantage of lower cardiac toxicity.37 Signs and symptoms of pulmonary arteriovenous
malformations
Decoene and colleagues described the successful use of inhaled
nitric oxide (iNO) in a woman with primary pulmonary hyperten-
The usual symptoms of PAVM are dyspnea, cyanosis, and club-
sion having C/S under epidural anesthesia.38 They observed no
bing, which are caused by hypoxemia due to right-to-left shunt.
interaction between epidural anesthesia and the use of iNO.
Others have reported the use of inhaled pulmonary vasodilators
and epidural anesthesia for C/S in pregnant patients with primary
pulmonary hypertension.39
Proponents of general anesthesia usually cite the risks of
decreased afterload, decreased preload, and acute RV failure
that may be precipitated by sympathetic blockade induced by
epidural or spinal anesthesia.35 Supporters of regional anesthesia
report that careful titration of the level of the block and the
judicious use of vasoactive drugs allow for satisfactory manage-
ment of anesthesia in these women. In addition, pulmonary
hemodynamic changes associated with laryngoscopy,40 which
increase the risk for precipitating right heart failure, are avoided
with regional anesthesia.
If general anesthesia is selected, nitrous oxide should be
avoided since it can increase pulmonary vascular resistance.
Isoflurane is the volatile anesthetic of choice for general anesthe-
sia because it has the least depressant effect on the myocardium. Figure 3.2 CT scan without contrast of right single pulmonary AV malformation
It should be used with an air/oxygen mixture.36 In labile patients, (pulmonary artery and vein seen on the same cut). Provided by Dr Frank Miller,
and/or those with severe disease, we recommend invasive mon- Professor of Radiology, University of California San Diego (UCSD) Medical
itoring and a high-dose narcotic ˜˜cardiac™™ anesthetic. One report Center, San Diego, California.



59
1 Cardiovascular and respiratory disorders



Table 3.1 Osler-Weber-Rendu disease (hereditary
hemorrhagic telangiectasia)

Inheritance: autosomal dominant
Incidence: affects 1 in 5000“8000
Features:
“ abnormal small blood vessels
“ AV fistulae in most organs, including lung and brain
“ telangiectasia of skin and mucous membranes causing epistaxis
and GI bleeding
Pregnancy worsens OWR secondary to:
“ systemic vascular dilatation
“ increased cardiac output
“ increased blood volume
“ weakened blood vessels from hormonal changes
May present in pregnancy with:
“ hemothorax
“ massive hemoptysis
“ arterial hypoxemia and paradoxical embolism for pulmonary shunts
“ congestive cardiac failure from hepatic AV shunts and portal
hypertension
“ AV fistulae in the epidural space and spinal cord
“ anemia

AV ¼ arteriovenous; GI ¼ gastro-intestinal


Most shunts associated with PAVM are right-to-left, but left-
to-right shunts of the bronchial, internal mammary, and inter-
Figure 3.3 Angiogram showing a large left pulmonary AV malformation.
costal arteries have been described.45 Paradoxical emboli may
Provided by Dr Frank Miller, Professor of Radiology, University of California
arise in the systemic circulation and pass through an enlarged
San Diego (UCSD) Medical Center, San Diego, California.
and engorged PAVM to affect the cerebral circulation. Likewise,
thrombi may originate on diseased valves or within a PAVM, due
Hypoxemia induces bone marrow to increase its production of
to the sluggish flow characteristics of AVM, and shower the cere-
hemoglobin and red blood cells, and may cause polycythemia. A
bral circulation. Hemoptysis and hemothorax occur when a
shunt of at least 25% is required to produce clubbing and poly-
lesion ruptures into the airway or pleural cavity, respectively.
cythemia. Although plasma volume remains normal, the red cell
mass and red cell volume increase.44,45 Frequent minor hemor- Paradoxical air emboli can occur when air enters the pulmonary
circulation following rupture of a PAVM. Such a rupture is rare,
rhages may prevent polycythemia.
but when it occurs is frequently massive and fatal. Rapid recogni-
Bruits often are audible on the chest wall over an AVM. A
tion, response, and repair or resection is necessary if the patient is
continuous hum is accentuated by systole and deep inspira-
to survive.48
tion.45,48 The characteristic feature on CXR is a peripheral, cir-
cumscribed, lobulated, noncalcified structure connected to the
hilum by tortuous vessels. Fluoroscopy of the lesion shows pulsa-
Osler-Weber-Rendu disease
tions with each heart beat, and increase and decrease in size with
About 60% of patients with PAVM suffer from Osler-Weber-
Mueller and Valsalva maneuvers (inspiration and expiration
Rendu disease (OWR), a disease with autosomal dominant trans-
against a closed glottis), respectively.
mission, also called hereditary hemorrhagic telangiectasia (see
According to Peery, cardiomegaly is ˜˜conspicuously absent™™
Table 3.1).51 About 15% of patients with OWR have PAVM,52,53
in patients with right-to-left shunt.49 If cardiomegaly is present
and will frequently exhibit multiple cutaneous and mucous mem-
on CXR, then suspect concomitant right heart disease or a left-
brane AVM, visible on the lips, labia, and oral mucosa. Epistaxis
to-right shunt. Rib notching occurs when a left-to-right shunt via
arising from lesions of the nasal mucosa is highly characteristic.51
an enlarged and tortuous intercostal AVM exists.49 The definitive
Pregnant women who have a family history of OWR, or have
diagnosis of PAVM is made by angiography.
mucocutaneous signs of the disease should be evaluated for the
Complications associated with the pulmonary lesions include
presence of occult pulmonary lesions. Patients with OWR tend to
vascular shunts, mitral valve disease, congestive heart failure,
have a high incidence of multiple PAVM, which generally grow
bacterial endocarditis, hemoptysis, and hemothorax due to rup-
more rapidly and produce more complications than in patients
ture. In addition, a cerebrovascular accident (CVA) may occur
without OWR.46
following cerebral embolism, thrombosis, or abscess.45,50



60
Chapter 3


Pregnancy and PAVM Management of the pregnant patient with PAVM
Pregnancy increases the risk of PAVM enlargement and rup- When PAVM become symptomatic during pregnancy, they can be
ture.47,48,52,53,54 The increase in size is a result of the increase in managed successfully using transcatheter spring coil or balloon
embolization.60,61 These procedures are done under local
blood volume and CO. Also, hormonal changes of pregnancy
directly affect the compliance of blood vessels with an increase anesthesia and successful occlusion will usually resolve the
in progesterone causing relaxation of arteriolar smooth muscle hypoxemia and high-output cardiac failure (see Figures 3.4, 3.5,
and further dilatation of the PAVM. Estrogens are associated with and 3.6). However, there has been a case report of recurrence of
the formation of spider telangiectasia and may contribute to an PAVM in pregnancy despite previous transcatheter embolother-
increase in PAVM size during pregnancy.46 Throughout preg- apy.62 This was discovered by contrast echocardiography after the
nancy there is a gradual increase in venous distensibility, which woman developed signs of worsening intrapulmonary shunt.
is greatest (150% of normal) just before delivery, similar to the When multiple lesions exist they may not be amenable to embo-
20“30% increase in venous distensibility observed during the lization, so pulmonary lobule or lobe resection may be necessary
menstrual cycle.55,56,57 The structure of the AVM contributes to to eliminate them. This surgery is most safely performed during
its fragility. The vascular spaces are lined by a single layer of
endothelial cells on a continuous basement membrane.58
Smooth muscle cells within the walls of the AVM are irregularly
shaped and do not form a continuous structure around the blood
vessels. Both endothelial cells and smooth muscle cells are vacuo-
lated, which suggests degeneration. There is no elastic tissue
within the walls. Thus, the walls of an AVM appear to be insuffi-
cient as a contractile element and are unable to respond to the
increased stress associated with the increased blood volume and
CO of pregnancy.58 The walls of an AVM, therefore, cannot con-
tract and control hemorrhage when they rupture.48,58 In addition,
there may be an increase in tissue plasminogen activator in the
endothelium of AVM, which impairs clot formation when bleed-
ing occurs.59




Figure 3.5 Same pregnant women postembolization with SaO2 93%. (Multiple
AVM prevent saturation from reaching 100%.) Provided by Dr Frank Miller,
Professor of Radiology, University of California San Diego (UCSD) Medical Center,
San Diego, California.




Figure 3.4 Angiogram of multiple AV malformations in a woman with Osler-
Figure 3.6 Coil used for coil embolization procedure, which is usually done on
Weber-Rendu disease. She was 24 weeks™ gestation (preembolization), with
an outpatient basis (Nester coilTM). Provided by Dr Frank Miller, Professor of
a history of transient ischemic attacks and SaO2 in 85“88% range. Provided by
Radiology, University of California San Diego (UCSD) Medical Center, San Diego,
Dr Frank Miller, Professor of Radiology, University of California San Diego (UCSD)
California.
Medical Center, San Diego, California.



61
1 Cardiovascular and respiratory disorders


the second trimester to avoid the period of fetal organogenesis patients and to check the coagulation status. Liver involvement
and to reduce the risk of preterm labor. One case report described can lead to high-output cardiac failure in patients with OWR,
an emergency thoracotomy at 27 weeks™ gestation for massive but cardiac function may return to normal after liver
transplantation.68
hemothorax associated with a pulmonary arteriovenous fistula in
a patient with OWR.63 Another association with PAVM is the risk of brain abscess and
cerebral AVM.69,70 One large series described neurologic compli-
Women with known PAVM or history of hereditary telangiectasia
should be followed with serial CXR and arterial blood gases to cations in 37% of patients with PAVM and these included transi-
detect progression of the PAVM.64 Antenatal diagnosis and treat- ent ischemic attacks, hemiplegia, brain abscess, and seizures. Any
ment of women with OWR and PAVM may prevent potentially life- patient with OWR presenting for an anesthetic must have neuro-
threatening fetomaternal complications.65 However, one patient, logic dysfunction ruled out by history, physical examination, and
with exercise-induced hypoxemia during pregnancy related to pul- special tests such as a brain scan. Patients with PAVM require
monary AV microfistulas, had spontaneous resolution of her symp- prophylactic antibiotics for all surgical and dental procedures to
toms after pregnancy. This was thought to be due to reversal of the avoid brain abscess or other distal infectious complications.
hormone-induced vasodilatation associated with pregnancy.66 Dyspnea may improve when the patient reclines. In the supine
position, there is decreased venous return due to the pressure of
the gravid uterus on the vena cava, decreased distension of the
Anesthetic management of women with PAVM
PAVM, and decreased shunt. Hemoglobin saturation improves.
There are few case studies to guide us when it comes to recom- Thus, it may be beneficial for the patient with a symptomatic
mending certain anesthetic and analgesic techniques for labor PAVM to labor without uterine displacement. We recommend
and delivery in women with PAVM. However, I believe that epi- that if this is attempted, the well-being of the fetus be monitored.
dural analgesia is acceptable. Placement is performed using loss Postpartum it is imperative that these patients be monitored
of resistance to saline to avoid the risk of introducing air into the carefully for any deterioration as the effect of the gravid uterus
vascular system and the risk of paradoxical air emboli. Since there on venous return is abolished and autotransfusion of blood from
may be coexisting epidural AVM, a computed tomography (CT) within the gravid uterus increases venous return and shunt. It
scan or magnetic resonance imaging (MRI) of the lumbar spine in may be necessary to resect or embolize the PAVM if the shunt
the early third trimester may be prudent. After delivery and epi- increases significantly.
dural catheter removal, the woman should be followed for signs Finally, it is important to consult surgical colleagues and peri-
of epidural hematoma, presenting as persistent paresthesia, pain, natologists early in the pregnancy of a patient with OWR. Delivery
or paralysis after expected resolution of analgesia. should be planned in a hospital with resources available to place
The epidural sensory level should be carefully titrated to a T10 chest drains if necessary, a well-stocked blood bank, and an
dermatomal level in order to avoid a significant reduction in SVR intensive care unit.
and worsening of right-to-left shunt. If required, SVR support may
be provided with a phenylephrine drip while monitoring the fetal
Peripheral pulmonary artery stenosis
heart rate. Arterial and pulmonary artery pressure monitoring is
necessary when heart failure is suspected, but PCWP measure- Peripheral pulmonary artery stenosis (PPAS) is a rare congenital
ment may be hazardous due to the risk of PAVM rupture. An condition of unknown etiology, which accounts for 2“4% of
arterial line also is necessary when infusing vasoactive drugs to congenital heart disease in women. It is characterized by multiple
coarctations of the distal pulmonary arteries.71 Peripheral pul-
increase SVR.
Cesarean section may be performed for obstetric reasons using monary artery stenosis may occur together with pulmonary ste-
regional or general anesthesia. The latter has the potential dis- nosis, atrial septal defect, ventricular septal defect, or Tetralogy
advantage of intubation-induced hypertension and the possibil- of Fallot. This condition occurs alone in approximately 40% of
cases.72 There may be an association of PPAS in offspring of
ity that high pulmonary inflation pressures might adversely
women who contract rubella during pregnancy.73
impact the integrity of the AVM. One case report of the anesthetic
management of a child with OWR and bilateral PAVM described Peripheral pulmonary artery stenosis is not usually consid-
the association between positive pressure ventilation and arterial ered a serious condition. Often it is diagnosed in early child-
desaturation, which improved with resumption of spontaneous hood when a loud, asymptomatic, continuous systolic murmur
respiration after extubation.67 That case was confounded by is investigated. Only when involvement of the peripheral pul-
coexisting congenital methemoglobinemia, another potential monary arteries is so extensive that it produces pulmonary
cause of cyanosis in that patient. hypertension is there a risk to the patient. Such a development
is uncommon.71
Arteriovenous malformations of the oral, pharyngeal, or tra-
Four cases of PPAS and pregnancy have been reported.71,72,73 In
cheal mucosa may exist. Therefore, thoroughly examine the
upper airway when considering general anesthesia and endotra- none of the cases did PPAS present a management problem for
cheal intubation in these patients to avoid inadvertent trauma to the anesthesiologist. During pregnancy, echocardiography or
the mucosal lesions. cardiac catheterization should be performed to detect elevated
Since OWR is sometimes associated with liver AVM and liver right heart pressures and assess the relative risk for heart failure
dysfunction, it is prudent to do an ultrasound of the liver in these during or after pregnancy. If the woman has pulmonary



62
Chapter 3



Table 3.2 Pulmonary artery aneurysms and pregnancy Table 3.3 Heart sounds and murmurs that may be heard in
patients with pulmonary artery aneurysms
Associated conditions
  Those consistent with patent ductus arteriosus (e.g. a to-and-fro
patent ductus arteriosus
 Marfan syndrome (cystic medial necrosis of the pulmonary artery) murmur heard best at the left second intercostal space, a
 Takayasu arteritis midsystolic hyperdynamic flow murmur of the mitral valve, and
 persistent pulmonary artery hypertension (primary or associated paradoxical splitting of S2)
 Intracardiac shunts (i.e. usually fixed, wide split S2, and murmur
with congenital cardiac defects that produce left-to-right shunting)
 infundibular stenosis of increased pulmonic flow)
 infective endocarditis  Pulmonary hypertension (i.e. tricuspid regurgitation characterized
Factors that may contribute to aneurysm formation and rupture by a holosystolic murmur, which increases with respiration, or
 atherosclerosis pulmonic and aortic regurgitation characterized by decrescendo
 trauma diastolic murmurs)
 syphilis
 pregnancy
 an increase in intravascular volume The heart sounds and murmurs that might be heard on clinical
 the pain and expulsive efforts of labor examination are listed in Table 3.3.
 involution of the uterus postpartum produces increased flow Chest radiographs may show pulmonary artery enlargement,
through the pulmonary arteries and raises vessel wall stress
cardiac hypertrophy, and decreased peripheral vascular markings
 increased deposition of mucopolysaccharides in the media of characteristic of pulmonary edema. The definitive diagnosis of a
major blood vessels occurs during pregnancy and may contribute
pulmonary artery aneurysm and its dissection, however, is based
to weakening of the artery
on angiography, CT, or MRI. The EKG will usually show right-axis
deviation due to RV hypertrophy.

hypertension, she should be managed as described for the patient
Anesthetic management during pregnancy
who has primary pulmonary hypertension (see earlier). If right
heart pressures are normal, or only mildly elevated, she requires
Pulmonary artery aneurysm and dissection almost invariably
no special management.
are associated with pulmonary hypertension,78 so the anesthetic
management is similar to that for primary pulmonary hyper-
Pulmonary artery aneurysm tension. The presence of a pulmonary artery aneurysm is life-
threatening but, as it occurs rarely, there is no consensus about
Incidence and clinical presentations
management. The options are predelivery repair, selective coil
embolization,76 or expectant management of pregnancy, labor,
Pulmonary artery aneurysms occur rarely and affect the main
pulmonary artery or a major branch of the pulmonary vascular and delivery without repair.
tree. Their incidence is approximately 1:10 000 to 1:20 000 of the During labor, the goal should be to minimize hemodynamic
general population.74 Associated conditions and contributory stresses such as systemic hypertension or profound swings in
factors are outlined in Table 3.2.74,75 preload and afterload. This is best achieved with a labor epidural
Rupture of aneurysms of the pulmonary arteries may produce using an infusion of dilute bupivacaine and/or intrathecal
massive and fatal hemoptysis. Death may also be caused by opioids. Epidural analgesia is induced gradually to a level of T10
cardiac tamponade if a pulmonary artery ruptures into the peri- to abolish the pain of labor and delivery, and prevent a catecho-
cardial sac.74,75 One report described a woman in the sixth month lamine-induced rise in CO and pulmonary artery pressure.
of pregnancy with a massive hemothorax secondary to a ruptured Forceps or vacuum delivery helps to shorten the second stage of
lingular artery aneurysm.76 Another report described a pregnant labor and avoids the need for expulsive effort by the parturient.
woman with a pulmonary artery aneurysm that the authors As in patients with primary pulmonary hypertension, peripheral
believed represented a case of primary pregnancy-related pul- arterial, central venous, and pulmonary artery catheters can pro-
monary artery aneurysm, since they could find no other predis- vide useful information and are mandatory if rapidly titratable
posing factors.77 The reasons that there is an increased risk of vasoactive medications are given to optimize cardiovascular
aneurysm formation and rupture during pregnancy are outlined function.
in Table 3.2.78 The principles for managing C/S in these patients are the
same as for patients with pulmonary hypertension and Marfan
syndrome (see later). Carefully titrated epidural anesthesia is
Signs and symptoms
preferable to subarachnoid block (spinal anesthesia) because
the degree and acuity of hemodynamic changes are less
A pulmonary artery aneurysm may cause shunting and cardiac
extreme. Spinal anesthesia for C/S, however, is not absolutely
failure. The patients present with exertional dyspnea, cough,
hemoptysis, chest tightness, and possibly hemothorax.74,75,76,77 contraindicated.



63
1 Cardiovascular and respiratory disorders


Takayasu arteritis (occlusive thromboarteropathy) described a woman with TA who survived three pregnancies dur-
ing a four-year follow-up period with no serious complication.91
Introduction If TA is symptomatic, 50% of pregnant patients will require
management of hypertension. Takayasu arteritis is not asso-
Takayasu arteritis (TA), or occlusive thromboarteropathy, is an
ciated with an increased rate of premature labor, but intrauterine
idiopathic condition characterized by obliterative panarteritis.
growth restriction is seen often in the fetus. Neonatal outcome
Symptoms are related to the organ systems involved by stenosis
and obliteration of large and intermediate arteries.79 This chronic is worse with abdominal aortic involvement, with severe hyper-
tension during pregnancy (especially in the presence of pre-
inflammatory disease can affect any artery, but significant signs and
eclampsia), and with delayed management of TA.92 Induction
symptoms arise from involvement of the aorta, its major branches,
and the pulmonary arteries.80 Upper extremity involvement has led of labor and C/S are performed for the usual obstetric
indications.90
to the name pulseless disease. Inflammation and subsequent fibrosis
Some patients with TA have resolution or improvement of their
affect the arterial media, intima, and adventitia, with intimal invol-
symptoms during pregnancy,93 whereas others demonstrate
vement being the direct cause of arterial stenosis and oblitera-
either no change or worsening symptoms.94 One woman pre-
tion.80,81 The characteristic pathologic change observed in affected
sented with massive hemoptysis during pregnancy.95
vessels is fibrosis. Signs and symptoms of TA reflect the vascular
The risk of cerebral ischemia is increased during pregnancy
beds and organs to which blood flow has been diminished.
especially during the first trimester and early postpartum period.
Takayasu disease affects women almost six times as often as
men79,82 and it affects Asian and Hispanic women predominantly.83 A small reduction in mean arterial BP in patients with severe
occlusive disease has the potential for syncope or severe cerebral
Although the onset of the disease occurs between the ages of 11 and
ischemia.94 Cerebrovascular accidents are likely when patients
48 years,84 it arises predominantly during the second and third
decades of life;83 therefore, pregnancy can be a coexisting condition. have severe narrowing of the branches of the aortic arch, elevated
systolic BP during the first stage of labor, and complications of TA
such as carotid disease or retinopathy.
Classification and prognosis
Avoiding pregnancy or elective termination of pregnancy is
recommended for patients with severe disease.94 The recommen-
Several classifications of TA have been proposed with some based
dation for women who decline termination of pregnancy is hos-
on the site of the anatomic lesions and others based on the
natural history and prognosis of the disease.80,85,86 Takayasu pitalization and symptomatic management. Elective C/S may be
used for women with severe disease as they approach term,
arteritis can be a severe and life-threatening disease, especially
especially those with retinopathy and severely elevated BP in
with more extensive vessel involvement, such as the descending
early labor. In those with mild TA, operative delivery is based
aorta, carotid, and vertebral arteries. Takayasu arteritis is also
solely on obstetric factors.
classified as severe if there is retinopathy, hypertension resistant
to treatment, aortic regurgitation, and presence of aneurysms,
especially in the pulmonary circulation.87 Hypertension is severe
Anesthetic management of women with TA
if the systolic brachial artery pressure is ! 200 mmHg and/or
The anesthetic management of women with TA must take into
the diastolic pressure is ! 110 mmHg; or the popliteal systolic
account the susceptibility of the patient to severe hypertension
pressure is ! 230 mmHg and/or the diastolic pressure
is ! 110 mmHg.86 Hypertension is most often associated with with its concomitant risk of CVA and cardiac failure. Hypotension
renal artery stenosis.88 Takayasu arteritis is a chronic disease is poorly tolerated and may result in cerebral ischemia. Other
considerations include the risk of pulmonary hypertension, and
with survival of up to 14 years after onset, and periods of remis-
sion are common.89 Early treatment with steroids, cytotoxic difficulty of hemodynamic monitoring due to the nature of the
disease.
agents, and anticoagulants can slow progression of the disease
The need for invasive hemodynamic monitoring must be

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