This document presents a case study of a 35-year-old male patient with recurrent hemoptysis. Testing revealed pulmonary arteriovenous malformations (PAVMs). PAVMs are abnormal connections between pulmonary arteries and veins, bypassing the capillary bed and causing a right-to-left shunt. The patient's PAVMs were likely hereditary as 90% of PAVMs occur in patients with Hereditary Hemorrhagic Telangiectasia. Percutaneous embolization is usually performed to occlude the PAVM connections and reduce the risk of complications from paradoxical embolism. Long term follow up is important after embolization to monitor for potential recanalization of treated

1. By
Mahmoud E. Abo El-Magd
Assistant lecturer of pulmonary and critical
care medicine
PAVM
A STATE OF THE ART
REVIEW

2. PAVM REVIEW 2

3. CASE PRESENTATION
PAVM REVIEW 3
• Male patient named Gamal Hamed Wahba, 35 year old , from
Domietta, married and has 3 offsprings ,working painting worker
previously butcher, and he is current smoker.
• The condition started 2 years ago by recurrent attacks of
coughing of frank blood . More than one cup per day .
• No other chest complaints .

4. CASE PRESENTATION - cont
PAVM REVIEW 4
• Gamal has hx of Pulmonary Tuberculosis 5 years ago and
received anti-tuberculous ttt for 6m .
• No other relevant medical diseases .
• Gamal has past hx of stabbing chest trauma on the left side 13 y
ago.

5. CASE PRESENTATION - cont
PAVM REVIEW 5
• Gamal appeared generally well . He had no positive signs in
general examination apart from finger clubbing .
• O2sat on room air : 88% .
• Local Examination : NAD .
• All laboratory parameters are within normal regarding to CBC ,
LFT , S.Cr , INR , ESR , Virology markers .

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21. INTRODUCTION
PAVM REVIEW 21
• Pulmonary arteriovenous malformations (PAVMs) are low-
resistance, high-flow abnormal vascular structures that most
often connect a pulmonary artery to a pulmonary vein .
• bypassing the normal pulmonary capillary bed and resulting in an
intrapulmonary right to-left shunt.
• Physiologic consequences depend on the degree of right-to-left
shunt and include hypoxemia, dyspnea, and cyanosis.

22. INTRODUCTION -cont
PAVM REVIEW 22
• The pulmonary capillary bed is
a sieve measuring 8 to 10 um in
diameter.
• PAVMs predispose to
complications of paradoxical
systemic embolization, including
stroke and brain abscess.
• Anti-biotics ?!!

23. INTRODUCTION -cont
PAVM REVIEW 23
• PAVMs usually are hereditary, with most associated with
hereditary hemorrhagic telangiectasia (HHT) .
• Hereditary PAVMs tend to increase in size over time, usually
expanding and becoming more evident in the second and third
decades of life.

24. PAVM REVIEW 24

25. BACKGROUNG
PAVM REVIEW 25
• HHT, known also as Osler-Weber-Rendu syndrome.
• Approximately 90% of adults with HHT have epistaxis;
however, up to 50% of patients with HHT have PAVMs .
• Conversely, of patients with PAVM, it is likely that as many as
90% will prove to have HHT.

26. PAVM REVIEW 26

27. BACKGROUNG - cont
PAVM REVIEW 27
• Curacao criteria :-
- recurrent epistaxis.
- mucocutaneous telangiectases ( lips – fingers – nose ) .
- family history ( 1st degree relative with HHT) .
-visceral involvement (GI telangiectases, brain, spinal,
pulmonary, or liver arteriovenous malformations).
• Definite : more than 3 criteria present .
• Possible : 2 criteria present .
• Unlikely : less than 2 criteria present .

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30. EPIDEMIOLOGY
PAVM REVIEW 30
• the approximate incidence of PAVM has been described to be
two to three per 100,000.
• male-to-female ratio of approximately 1:1.5 to 1.8 .
• most are diagnosed in the first 3 decades of life.

31. PAVM REVIEW 31

32. PATHOPHYSIOLOGY
PAVM REVIEW 32
• PAVMs may be single or multiple, unilateral or bilateral, and simple or
complex.
• Most solitary PAVMs are seen in the lower lobes, with the left lower
lobe being the most common location followed by right lower lobe.
• The majority of multiple PAVMs are also confined to the lower lobes.
• Simple PAVMs receive blood through a single artery, and complex
PAVMs receive blood through two or more arteries.

33. PATHOPHYSIOLOGY- cont
PAVM REVIEW 33
• The afferent supply is most often a branch of the pulmonary
artery; however, in rare cases, it can derive from the systemic
circulation, including the bronchial and intercostal arteries.
• The efferent limb of the PAVM often communicates with
branches of the pulmonary vein, although direct communication
with the inferior vena cava have been described.

34. PATHOPHYSIOLOGY- cont
PAVM REVIEW 34
• The abnormal segment between the pulmonary artery and the
pulmonary vein is fragile and may rupture and bleed as the
PAVM size increases and manifests as hemoptysis or
hemothorax.
• Right-to-left shunt that causes hypoxemia and paradoxical
emboli are the main complications of PAVM.
• In healthy individuals, shunt is usually ,2% of the cardiac output.

35. PATHOPHYSIOLOGY- cont
PAVM REVIEW 35
• The degree of shunt determines the severity of hypoxemia, with
severe symptoms present when the shunt exceeds 20% of the
cardiac output.
• The shunt present in PAVM causes hypoxemia because blood
flows directly from the pulmonary artery to the pulmonary vein,
bypassing the capillary-alveolar barrier with no effective gas
exchange.

36. PAVM REVIEW 36

37. ETIOLOGY
PAVM REVIEW 37
• Most PAVMs are hereditary, with about 90% occurring in patients with HHT .
• The majority of the non-HHT-related PAVMs are idiopathic.
• Other causes include :-
- infections, such as schistosomiasis and actinomycosis , tuberculosis .
- trauma , post-thoracic surgery.
• PAVMs can also occur secondary to hepatopulmonary syndrome (HPS) .

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40. CLINICAL MANIFESTATIONS
PAVM REVIEW 40
• Signs and symptoms of patients with PAVM vary depending on
the size, number, and flow through the PAVM.
• In general, a single PAVM of less than 2 cm in size does not
usually result in symptoms.
• Patients may be completely asymptomatic or experience
dyspnea on exertion.

41. CLINICAL MANIFESTATIONS - cont
PAVM REVIEW 41
• Hypoxemia at rest or with exercise may be present, especially
in the presence of a significant intrapulmonary shunt.
• Orthodeoxia (worsening hypoxemia when upright) and
platypnea (worsening dyspnea when upright) may be evident
because 80% of PAVMs are in the lower lung fields.
• The classic triad of dyspnea, cyanosis, and clubbing is seen in a
minority of patients.

42. CLINICAL MANIFESTATIONS - cont
PAVM REVIEW 42

43. PAVM REVIEW 43

44. COMPLICATIONS
PAVM REVIEW 44
• Neurological
x Cerebral abscess (25%)
x Cerebrovascular strokes (20%)
x Transient ischaemic attacks (55%)
x Migraine (40%)
x Seizures (8%)
• Cardiovascular
x Pulmonary hypertension
x High output cardiac failure
x Paradoxical embolism

45. COMPLICATIONS - cont
PAVM REVIEW 45
• Pulmonary
x Haemoptysis
x Haemothorax (2%)
• Haematological
xPolycythaemia
• Surgical resection, with its morbidity and peri-operative
complications .

46. PAVM REVIEW 46

47. DIAGNOSTIC TESTING - CXR
PAVM REVIEW 47
• Classically appears as a well-defined round or oval sharply
defined nodule or mass .
• routine screening with chest roentgenogram insensitive.

48. DIAGNOSTIC TESTING – TTCE
(bubble echocardiogram)
PAVM REVIEW 48
• Higher sensitivity and safety is
seen with contrast
echocardiography.
• TTCE is a safe screening test for
intrapulmonary shunt, with a
sensitivity of 100% and a
specificity ranging from 67% to
90%.

49. DIAGNOSTIC TESTING – TTCE
(bubble echocardiogram)
PAVM REVIEW 49
• TTCE was performed by placing an IV line to which two 10-mL
syringes were connected, one filled with an 8-mL physiologic
saline solution and the other with 1 mL of air. Subsequently, 1
mL of blood was drawn in the air-filled syringe and mixed with
the saline-filled syringe by reverse flushing between both
syringes, creating agitated saline (microbubbles).
• The patient was positioned in the left lateral decubitus position,
and 10 mL of agitated saline was injected while projecting the
four-chamber apical view without a Valsalva maneuver.

50. PAVM REVIEW 50

51. DIAGNOSTIC TESTING – TTCE
(bubble echocardiogram)
PAVM REVIEW 51
• Pitfalls of TTCE : -
- very sensitive , it may be positive even if no PAVM detected
in CT .
- it remains positive after treatment in up to 90% of patients .
• Such results may correspond :-
- false positive test result .
- diffuse and or microscopic PAVM .

52. PAVM REVIEW 52

53. DIAGNOSTIC TESTING – CCT scan
PAVM REVIEW 53
• CCT scan is not part of the PAVM screening process.
• Used in further evaluation of patients with a high suspicion of
PAVM. In the setting of a TTCE suggestive of intrapulmonary
shunt.
• Maximum intensity projection reconstruction (MIPR) showing
one or more enlarged arteries feeding a serpiginous mass or
nodule and one or more draining veins is diagnostic .

54. PAVM REVIEW 54

55. DIAGNOSTIC TESTING – pulmonary angiography
PAVM REVIEW 55
• Pulmonary angiography generally is no longer necessary as a
diagnostic procedure alone.
• It is reserved for therapeutic purposes after a diagnosis has
been established.
• It remains the gold standard for inconclusive cases.

56. DIAGNOSTIC TESTING – MRI
PAVM REVIEW 56
• Noninvasive methods available, contrast-enhanced magnetic
resonance angiography (CE-MRA).
• Provide precise information on the number, location, and
complexity of PAVMs.
• The possibility of detecting small PAVMs.
• Avoid complications of catheter angiography .

57. DIAGNOSTIC TESTING – MRI
PAVM REVIEW 57

58. DIAGNOSTIC TESTING – MRI
PAVM REVIEW 58
• The main disadvantages are :-
- expense.
-potential side effects of gadolinium-based contrast in
patients with renal disease .
- time of the procedure .
- limited availability in some centers .
-specialized nature of the test.

59. DIAGNOSTIC TESTING – Right-to-Left
Shunt Assessment
PAVM REVIEW 59
• Radionuclide imaging with 99m Tc-labeled macro-aggregated
albumin lung-brain perfusion scanning .
• The albumin microspheres have particle diameters of less than
20 um and are normally trapped in the capillaries of the lung.
• In the presence of PAVM, these particles pass through the lung,
and shunt fraction can be calculated by radionuclide scanning
over the brain, kidneys, or both.

60. DIAGNOSTIC TESTING – Right-to-Left
Shunt Assessment
PAVM REVIEW 60
• Radionuclide imaging is expensive, requires radiation, and is
not uniformly available at many facilities.
• radionuclide imaging does not differentiate between a cardiac or
pulmonary source of AVMs.

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63. TREATMENT AND MANAGEMENT
PERCUTANEOUS TRANSCATHETER
EMBOLIZATION
PAVM REVIEW 63
• Percutaneous TCE is the gold standard for the treatment of
PAVM because it is effective in reducing the risk of paradoxical
embolism and other complications associated with PAVM.
• less invasive and easy to repeat .
• disadvantages include collateralization and revascularization
over time.

64. PERCUTANEOUS TRANSCATHETER
EMBOLIZATION
PAVM REVIEW 64
• Major indications for treatment are :-
- prevention of neurologic complications, including stroke and
cerebral abscess from paradoxical embolism.
- improvement in exercise tolerance .
- reduction in migraine prevalence .
- prevention of lung hemorrhage.

65. PERCUTANEOUS TRANSCATHETER
EMBOLIZATION
PAVM REVIEW 65
• During embolization, the supplying artery immediately preceding
the PAVM is the target to occlude the feeding vessel just
proximal to the aneurysmal sac .
• The deployed coils are designed to coil within the vessel lumen
and carry micro fibers that activate platelets to generate an
occluding platelet plug.

66. PERCUTANEOUS TRANSCATHETER
EMBOLIZATION
PAVM REVIEW 66
• Amplatzer vascular plugs (AVPs) and balloon devices provide
direct obstruction to vascular flow.

67. PERCUTANEOUS TRANSCATHETER
EMBOLIZATION
PAVM REVIEW 67

68. PERCUTANEOUS TRANSCATHETER
EMBOLIZATION
PAVM REVIEW 68
• Recanalization and collateralization of the post-embolization
PAVM can present in the range of 5% to 20%.
• No device appears to be superior in preventing recanalization.
• Study of 28 PAVMs showed that recanalization did not develop
between 6 and 40 months in patients treated with AVP and coils.

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72. TREATMENT AND MANAGEMENT
SURGERY
PAVM REVIEW 72
• Surgical resection is rarely necessary because the
majority of PAVMs are amenable to TCE.
• Indications for surgery :-
- Complex of diffuse PAVMs not amenable to
embolotherapy.

73. TREATMENT AND MANAGEMENT
SURGERY
PAVM REVIEW 73
• Surgical techniques depend on the complexity of the PAVM and
include :-
-local excision.
-segmental resection.
- lobectomy.
- ligation.
- pneumonectomy.
- lung transplant.

74. PAVM REVIEW 74

75. FOLLOW-UP
PAVM REVIEW 75
• Recurrence of PAVM occurs after 15% of embolizations .
• Unpredictable .
• Results from :-
-recanalization of occluded PAVMs.
-collateralization from adjacent arteries.
- missed accessory pathways.

76. FOLLOW-UP - cont
PAVM REVIEW 76
• Long-term follow-up post-embolization is accomplished with
CCT scan performed 6 to 12 months after embolization and then
every 3 to 5 years.

77. PAVM REVIEW 77

78. SCREENING
PAVM REVIEW 78
• All patients with hereditary haemorrhagic telangiectasia should
undergo routine screening .
• contrast echocardiography is very sensitive .
• contrast echocardiography can be too sensitive by detecting
clinically insignificant micro-vascular shunts .

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80. PAVM AND PREGNANCY
PAVM REVIEW 80
• PAVMs often increase in size and number during pregnancy .
• Mostly during 2nd and 3rd trimester due to hormonal and
hemodynamic factors .
• Patients with known hx of PAVM or HHT should have close
monitoring during pregnancy.
• After 16 week of gestation , embolotherapy can be safe and
effictive.

81. PAVM REVIEW 81

82. HOME TAKEAWAYS
PAVM REVIEW 82
• PAVMs are abnormal vascular structures that most often
connect a pulmonary artery to a pulmonary vein, bypassing the
normal pulmonary capillary bed and resulting in an
intrapulmonary right-to-left shunt.
• The main complications of PAVM result from intrapulmonary
shunt and include stroke, brain abscess, and hypoxemia.

83. HOME TAKEAWAYS - cont
PAVM REVIEW 83
• The most common cause of PAVM is HHT.
• Embolization with the use of TCE is the treatment of choice and
is safe and effective in experienced hands.
• Collateralization and recanalization may occur, so lifelong
follow-up is important.

84. HOME TAKEAWAYS - cont
PAVM REVIEW 84
• Patients with PAVM should receive antibiotic prophylaxis for
procedures likely to induce bacteraemia.
• Air-filters should be placed in IV access site prior to any
procedure .
• Family members of patients with PAVMs should be screened.
• No diving .