Thrill or vibration may indicate:
- Post-stenotic turbulence
- Patent dialysis access site
- No image, but the signal can be processed audibly or displayed as a waveform.
- No range specificity.
- 2 crystals
- -Uni directional Doppler (forward and negative flow are heard in both ears)
- -Bi directional Doppler (separates flow direction out in both ears)
- Use a zero-crossing detector.
- Estimation of mean frequency.
- -Less sensitivity.
- -High velocities underestimated.
- -Low velocities overestimated.
Limitations to Arterial Non-imaging Testing:
- Patient's with casts or extensive bandages.
- Waveforms may be affected by ambient temperatures.
- Uncompensated CHF may result in dampened waveforms.
- Unable to discriminate stenosis from occlusion.
- Technically dependent test.
- Improper probe position.
- Inadvertent probe motion.
- Incorrect angle of incidence.
- Inadequate amount of gel.
- Excessive pressure on the probe tip.
- Insufficient period of rest before testing.
- Fast Fourier Transform
- Shows all of the different velocities.
- Signal can be displayed over time.
Determination of time of flow.
Doppler frequency shift in kHz or velocity in cm/s or m/s.
Amplitude of the returning gray scale.
Factors that influence waveform shape:
Very few scintillations in __________.
-Spectral Broadening in diastole then systole after 50% hemodynamic significant stenosis.
-PEDV will also increase.
- Rapid upstroke
- Sharp peak
- Rapid downstroke
- Flow reversal
- Resumption of forward flow.
- Rapid upstroke
- Sharp peak
- Fairly rapid downstroke
- Flow reversal
- No resumption of forward flow.
- Slow upstroke
- Rounded peak
- Slow downstroke
- No reversal
- Pre-stenotic signal may be normal if adequate collateral run off.
- Adequate collateral flow, may present a high resistant signal maybe heard/recorded as a high pitched, high frequency signal over the area of stenosis from a flow reducing lesion.
- Post-stenotic turbulence may lose 2nd and 3rd component.
- Just proximal to an occlusion there may be no signal; if chronic occlusion there may be a low resistant signal due to collaterals.
- High resistance in front of or proximal to a stenosis or occlusion.
- Dampened waveform always distal to stenosis.
Pulsatility Index (PI) OR Gosling
- Used to quantify the degree of pulse wave dampening at different measurements.
- Used in LE or TCD.
- Divide peak-to-peak difference by the mean frequency.
- Differentiate in flow from out flow disease.
CFA ≥ 5 is normal --- 6 and 7 range.
<5.0 Suggest aorta-iliac > 50%
Pop A --- 8 is normal
PTA 12 to 16 is normal
PI increases from proximal to distal leg.
Acceleration Time (AT)
- Helps to differentiate inflow disease from outflow disease.
- Acceleration time of <133 m/s suggest absence of significant iliac disease.
Resistivity Index (RI) OR Pourcelot's
- First used on CCA waveforms as an indicator of the peripheral resistance.
- Also used with kidneys and kidney transplants.
- Normal Value = 0.73 ± 0.04 [0.75 or below]
- Abnormal Value = 0.8 ± 0.07 [0.75 or above]
- If RI = 1.0 probably have an occlusion.
6 P's of acute arterial disease:
2nd most common site for the non-diabetic:
- Aortoliac segment
- Inflow disease
HT to AK gradient reflects ______ disease.
AK to BK gradient reflects ______ disease.
BK to ankle gradient reflects ______ disease.
- Pop A
- Tibial and Peroneal
- Mild disease (single level)
- Severe disease (multiple level)
- Rest Pain
- Limb threatening
Reactive Hyperemia Testing:
- Prolonged pressure drop.
- Single-level disease shows <50% drop in ankle pressure with RHT.
- Multi-level disease show >50% drop in ankle pressure.
The purpose of UEA SEG is to determine:
Primary Raynaud's Disease:
Secondary Raynaud's Phenomenon:
No underlying disease or associated medical problems.
There is an underlying disease or condition that causes it.
Treatment with medications:
- Calcium channel blockers.
- Alpha blockers
- Nonspecific Vasodilator
Paget-Schroetter Syndrome (PSS):
Effort thrombosis of the upper extremity cause by hypertrophic muscles or congenital abnormalities of TOA (Thoracic Outlet Area).
- Idiopathic and has high risk of death.
Venous thrombosis develops in patients with central venous catheters, pacemakers, or cancer and accounts for most cases.
- 115 ± 25 cm/s
- 90 ± 15 cm/s
- 69 ± 15 cm/s
- 61 ± 20 cm/s
% stenosis PSV Velocity Ratio
Normal <150cm/s <1.5:1
30-49% 150-200cm/s 1.5:1-2:1
50-79% 200-400cm/s 2:1-4:1
>75% >400cm/s >4:1
No color, NONE ---------
Arteriovenous Fistula (AVF):
- An abnormal communicate between an artery and a vein.
- May be congenital or acquired from a needle stick.
Most common AVF's are:
________ at the wrist.
________ at the antecubital fossa.
- Radiocephalic (Brescia Cimino)
Why an AVF would be created on purpose?
- End-Stage Renal Disease (ESRD)
- Dialysis patients, to filter their blood.
4 most common grafts:
- Forearm loop graft
- Polytetrafluroethylene (PTFE)
Complications with grafts:
- Develop thrombosis or occlusion.
- Venous anastomosis slower flow more likely to develop stenosis.
- Arterial steal.
- Venous hypertension.
- Rt. side heart pressure becomes greater than left.
Results of graft:
- High flow/low resistance.
- Spectral broadening.
- PSV should be 100-400cm/s
- Graph occluded.
Rt. pressures increase due to increase in preload. Therefore there is an increase in CO.
Reverse Saphenous Vein Graft (RSVG):
The GSV is taken out and reverse 180 degrees so the valves don't interfere with blood flow.
Don't have to do anything with the valves.
The mismatch in sizing could create stenosis.
In Situ Vein Graft:
Vein stays in place.
Valvulotome is a device which removes valves from veins.
- Bypassing the distal abdomen aorta usually below kidneys to femoral arteries.
- Usually long recovery.
Axillofemoral and Femorofemoral/ Axillary Fem-Fem:
Bypassing Axillary A. down outside of rib cage to CFA at inguinal ligament.
- CFA to CFA
- Disease in all of aorta and iliacs.
Disease in only Iliac.
Bypass CFA to distal SFA or to Pop A.
Fem to DP
Lt. prox Subclv A bypass into Lt CCA.
- Only done with symptoms or if occlusion occurs.
When Duplexing Bypass Grafts:
Identify type of graft.
Determine how long.
- prox native vessel
- Rt. prox anastomosis site (Inflow)
- Through graft. (prox, mid, dist)
- dist anastomosis site (Outflow)
- dist native vessel
Duplexing Bypass Grafts scan:
- 1 months
- 3 months
- 6 months
- 12 months
- and then yearly.
Before patient leaves with new bypass graft...
A decrease of _____ index is pending graft failure.
A change in ____ to ____ waveform is a warning.
Tri to Bi
Failure of Bypass Grafts:
- Angioplasty and stenting in graft.
- Graft fail in 1 or 2 days might try a thrombolytic/catheter.
- Localize pathologies missed. (Determine the exact location).
- Assess hemodynamics right away.
- Make corrections immediately.
Percutaneous Transluminal Angioplasty (PTA):
- Non-surgical but still invasive.
- Plaque is <2 cm in length.
- Plaque is fractured and pushed against the vessel wall.
- Remove the plaque.
- Chews up plaque and is absorbed in the blood stream.
- Drug that prevents further clotting. (Interferes with fibrin production).
- Heparin is given to acute thrombus IV drip or subcu.
- Coumadin or Warfrin takes 3-5 days to build up in system. Long term therapy.
- Stops production of Vitamin K.
- Needs blood tests done.
- Prothrombin time levels show how coumadin is working.
- Dissolves the thrombus that is already there. Ex: Streptokinase and Urokinase.
- Used on:
- Acute PE
- Graft Occlusion
- Anti platelet: Slicks down platelets so they don't stick together.
- Ex: ASA (aspirin) Plavix
Compressing Pop A by head of gastrocnemius muscle or fibers in that area.
- Unilateral claudication with exercise seen in young athletes.
- Difficult to reproduce symptoms.
- Do a resting study.
- Dorsal Flexion- PVR.
- Angiogram with dorsal flexion.
- Anterior Medial Posterior
- DP PTA Pero A
- Swelling in one or more of these compartments in a limb.
- Interstitial pressure becomes greater than transmural pressure (inside a vessel).
- Due to trauma.
- Flow become obliterated.
- Tissue becomes ischemic and necrotic.
Compartment Syndrome treatment:
3 stick needle with gauge and measure pressure.
Fasciotomy- make an incision and open fluid leaks out. Risk of infection is greater.
_____ million cases per year.
_____ cases of PE.
_____ deaths from PE.
- Inflammation in superficial veins and development of thrombus.
- Involves superficial veins only.
- GSV drains into CFV
- SSV drains into Pop V
- Cephalic V drains into Axillary V
- Basilic V drains into Brachial V
Palpable subcutaneous cord.
- Heat application
- Anti-inflammatory drug
- Evaluate the extent of thrombus.
- Does it extend into the deep system?
- If it does propagate into the deep system, hospitalization and Heparin therapy.
- 1. Stasis
- Prolonged sitting, surgery, post-surgical, trauma, 3rd trimester of pregnancy, acute paralysis.
- 2.Vein Injury
- Trauma Hx of DVT, Catheters.
- Antithrombin III, Protein C, Oral contraceptives, Pregnancy, Factor V Liden.
DVT Risk Factors:
- Post-operative states
- Hx of DVT
- Oral Contraceptive
Acute DVT Symptoms:
- Persistent calf pain or tenderness posterior medial calf.
- Calf or leg swelling.
- Asymptomatic- Fever
Calf Vein Thrombus:
- Solar Sinuses/Gastrocs most common site of thrombus origin.
- Many varicosities.
- Anticoagulant for 6 weeks or more.
- US follow up
DVT: Femoropopliteal vein
- Risk of PE increase greatly.
- Patients must have therapeutic anticoagulation.
- Caval filter placement.
- Started on Heparin and coumadin.
- Check PT (Prothrombin time-check INR International normalized ratio). and PTT (Partial thromboplastin time- evaluates the intrinsic coagulation system)
- Increase in calf pain
- Swelling of calf
- Symptoms similar to fem-pop thrombus
- Difficult to image iliac V
- Doppler interrogation may help.
- May need to do Venography (inject vein with contrast)
- Occurring more frequently due to the use of central venous lines.
- Other causes:
- Radiation Therapy
- Paget Schroetter Syndrome
- Vague discomfort in arm
- Marked arm swelling.
- Prominent superficial veins.
2 main goals for venous imaging to detect DVT:
- 1. Determine presence or absence of DVT.
- 2. Risk of embolization.
- 14 days or less old
- low echogenicity even anechoic in beginning
- vein distention
- loss of compressibility
- free floating thrombus
- gradual process for acute to subacute
- increase echogenicity
- decrease thrombus size
- reduce vein size
- free floating thrombus now adhered
- resumption of flow-recannalization
- months to years
- thrombus that has not lysed is invaded by fibroblasts and becomes organized as fibrous tissue
- echogenicity is greater or may blend in with the surrounding tissue
- valve abnormality
- small % of patients will dissolve thrombus totally
NON Vascular Structures:
- Lymph node
- Baker's cyst
Iliac Vein Compression Syndrome (IVCS) OR
- Compression of the Lt. CIV between Rt. CIA and overlying vertebrae.
- External compression of the vein causes intraluminal changes that could cause DVT.
Candida Septic Thrombosis:
- Invasive candidiasis is a fungal infection that occurs when Candida species enter the blood, causing bloodstream infection and spread throughout the body.
- Low birth weight babies, surgical patients, and those with weakened immune systems.
High pressure in the veins
- 1. Fluid accumulation (edema)
- 2. Hemosiderin hyper pigmentation (brawny)
- 3. Venous ulcer
Venous Insufficiency Treatment:
- Vein stripping.
- -Inject saline solution into the reticular (spider vein)
- Compression stockings
- Una boot and medication to heal ulcers
- New valves
- RFA ablation
Tributary VS. Perforator
- Appears to come in from above the layer of fascia.
- Appears to come in from below the layer of fascia.
- < 0.50s Normal
- 0.50 to 1s Mild to Moderate
- 1-2s Moderate
- >2s Severe
- Empty calf by heal toe raises.
- Filling of cutaneous vessels.
- ≥20s normal
- <20s abnormal
Rare Venous Disorders.
- Congenital anomaly.
- Born with no deep veins below the Iliac.
- Can be totally absent or hypoplastic (they are there but non-functioning, underdeveloped)
- Usually affects 1 limb.
- May have birth marks - port wine stain.
- Bone and soft tissue hypertrophy.
- Venous varicosities.
Rare Venous Disorders:
- Congenital have no deep veins or hypoplastic.
- Arterial/Venous like an AVF malformations in cerebral vessels.
- Port wine stain on one side of the forehead and eyelid.
Rare Venous Disorders:
- Significant capillary hemangiomas
White leg (milk leg) pale, painful, swollen, results from arterial spasms that occur secondary to extensive acute iliofemoral vein thrombosis.
Bluish in color, painful, swollen, the arterial circulation is being compromised, complication of an acute iliofemoral vein thrombosis.(The severely reduced venous outflow causes a marked reduction in arterial flow. Tissue hypoxia can develop, leading to venous gangrene.)
- Acute thrombosis, proximally slow sluggish flow.
- RBC's are stacked.
- Compressible, but will eventually start to clot.
Different ways of diagnosing:
- Ascending Venography- inject into the foot and evaluate for DVT, or congenital abnormalities, chronic venous obstruction.
- Descending Venography- incompetency in venous valves.
- Anticoagulants- Heparin, Lovenox
- Lytic therapy
- Vena cava filters