DEEP VEIN THROMBOSIS (DVT)
________________________________________________________________
________________________________________________________________
INTRODUCTION
:
Venous thromboembolism (VTE) is a serious preventable cause of morbidity & mortality in the world. DVT & pulmonary embolism (PE) are distinct but related aspects of VTE. Being silent (80% DVT) and difficult to diagnose it poses great challenges in establishing diagnosis. Higher incidence, underestimation of risk, low level of clinical suspicion, under-used prophylaxis with high fatality has made DVT a world wide cause for concern. The immediate need of the hour is to have standard guidelines for management of DVT. These guidelines have to be practical, acceptable and implementable in institution all over.
D.V.T.
FACTS : (1)
DEFINITION
:
A deep vein thrombus is a blood clot or thrombus that develops in deep vein usually in leg, here they pass through the centre of leg, surrounded by muscles, less commonly D.V.T. occurs in deep veins of arm or pelvis.
___________________________________________________________________________
*
Prof. & HOD, ** Assoc. Prof, *** Asst. Prof., @ PG Trainee (DNB)
Dept.
of Medicine, R.D. Gardi Medical College, Ujjain (M.P.), INDIA
1
MECHANISM
:
Based on Virchow’s triad; development of D.V.T. is
primarily related to the stasis of blood flow, vascular wall damage, activation
of clotting system and hypercoaguable state.
Blood passing through the deepest veins in calf or
thighs flows relatively slowly than from a solid clot which becomes wedged in
the veins.
INCIDENCE
:(1)
U.S. 100/100000-500/100000 at 80 yr age
U.K. 1 in 2000
CHINA 17.1/100000 ; 81.1/100000> 66 yr age
SINGAPORE : 388 cases between 1996-97 broke the
myth-V.T.E. rare in Asia, India & South Asian countries : 6-75%, not well
Highlighted.
PREDISPOSING
FACTORS :
A,
Patient Factors :
(ii) Pressure
on veins by fetus
(ii) Dehydration
B.
Surgical Conditions : (5)
-
Specially
includes surgery for more that half an hour duration
-
Abdominal,
pelvis, orthopedic surgery to lower limb
-
Increased
use of central venous line has caused more involvement of upper limbs in D.V.T.
C.
Medical Conditions :
-
M.I./
Heart failure
-
Inflammatory
bowel disease
-
Malignancy
or its treatment
-
Nephrotic
syndrome
-
Behcets
syndrome
-
Homocysteinemia
-
Major
injuries/ paralysis
D.
Hematological Disorders :
-
Primary
proliferative polycyathemia
-
Essential
thrombocythemia
-
Myelofibrosis
/ Myeloproliferative diseases
-
Paroxysmal
nocturnal hemoglobinuria
2
E.
Anti-Coagulants Deficiencies :
-
Antithrombin
III : such patients are also relatively resistant to heparin
Therapy.
-
Factor
II Leiden : Genetic polymorphism of P.T. gene
-
Factor
V Leiden : Mutation leading to APC resistance
-
Heparin
cofactor II
-
Prothrombin
G20210 A mutation
F.
Increased Clotting factors :
-
XI
and VIII
G.
Antiphospholipid Antibodies :
-
Lupus
anticoagulant
-
Anti
Cardiolipin antibodies
SIGNS
& SYMPTOMS :
D.V.T. of iliac, femoral or popliteal vein –
U/L leg swelling, warmth, erythema, increased
tissue turgor, distention of superficial veins and appearance of prominent
venous collaterals. In some patients deoxyhemoglobin in straight veins gives it
a cyanotic hue called as ‘Phlegmasia cerulea dolens’.
In markedly edematous legs, interstitial tissue
pressure may exceed capillary perfusion pressure causing pallor – ‘phlegmesia
alba dolens,.
Tenderness is present along individual vein and a
cord may be palpable.
D.V.T. of calf vein.:-
It is difficult to notice because of only one of
multiple veins involved allowing adequate venous return through the remaining
patient Vessels . The most common complaint is of calf pain which is noticeable
or worse when standing or walking. Examination shows posterior calf tenderness,
warmth, increased tissue tigour or
modest swelling and rarely cord. Sometimes mild fever may occur usually < 380C.
HOMANS,
SIGN :
Pain in calf on forcible dorsiflexion of the foot.
The sign is unreliable and may enhance risk of P.E.
However 95% of patients with symptoms suggestive of
D.V.T. have another diagnosis and 50-80% of DVTs have no symptoms.
DIAGNOSIS
: (6)
A.
Clotting Properties of blood :
(i)
D-Dimer : it is by-product of clotting material. Measurement gives an
indication hypercoagubility.
(ii)
apTT/PT/INR : Increased valve suggests clotting defects
(iii)
125 I fibrinogen leg scanning : this indicates vascular
insufficiency.
B.
Venography :
- This
is reference standard for diagnosis of D.V.T.
-
Contrast medium is injected into superficial veins of foot and directed
to words deep veins by
tourniquets. Presence of filling defects or absence of filling of deep
veins indicates D.V.T.
-
Limitations
: a.) Difficult to perform
-
b.) Require expertise for interpretation
3.
-
Complications
: a.) Foot/calf pain
b.) Superficial Phlebitis
c.) D.V.T.
d.) Hypersensitivity to
radio contrast media
C.
Impedence Plethysmography : (7)
This measures changes in vevouls
capacitance during physiological maneuvers verous obstruction becount the
normal changes in venous capalitance that ocular following inflation or
deflation of thigh usf.
Sensitivity
83% , Specificult 92% Sereal plethysmography increase sensitivity.
False
+ : a. Tensing leg muscles
b. Compression by extravasculars mass
c. Increased central pressure obstructing venous outflow
d. Decreased arterial flow
It
is not sensitive to calf veins thrombosis
D.
Real time B-mode (or Duplex) USG :
This is 2D imaging and pulse wane doppler
interrodation
Direct visualization of major vascular
channels and Doppler signals provides an audible and graphical depiction of
blood flow. Failure to collapse the Vascular lumen completely with gentle probe
pressure & finding of intraluminal echogenic material resulting from clot
confirms the diagnosis of thrombosis. Sensitivity for proximal D.V.T. 97% and
specificity 99%
False
+ve : d/t inability to compress femoral vein d/t pregnancy or pelvic tumor.
False
–ve : missing small clots
Misinterpreting
total occlusion of femoral vein because of dilated collatrals.
Predictive
value is more than impedence plethysmography but this also is less sensitive in
inentifing isolated calf vein thrombosis. sensitively 50-75% specificity 95%
DIFFERENTIAL
DIAGNOSIS :
Includes
all disorder causing U/L leg pain or swelling :
TREATMENT
:
Aims
of Rx : To prevent (i) Clot
becoming larger
(ii)
Clot becoming loose & traveling to lungs
(iii)
New clot formation
(iv)
Post thrombotic syndrome
4.
General
Therapeutic Measures :
1. BED REST : The affected extremity is elevated above the level of heart until edema or tenderness subside. Rest decrease oxygen requirement, Limits risk of thrombus dislodgement, promotes fibrinolytic breakdown and clot destruction. Elevation improves venous flow using gravity to reduce pressure gradient between the extremity and heart.
2. EXERCISE :
Encourage the patient to perform gentle foot &
leg exercises every hour. Dumping effect of muscle action promotes various
return. Gentle exercise minimize further thrombus formation but overtly
vigourous ones may dislodge the clots.
Isometric : eg plantar flexion against foot board –
recommended after surgery, they increase venous flow but at the same time raise
B.P.
ISOTONIC : eg active passive foot leg flexion &
extension and ankle rotation are preferred.
3. FLUIDS : Increase fluid intake upto 2 l/day
unless contraindicated. This increase vascular volume and decrease viscosity of
blood thus improving the blood flow.
4.AVOID DEEP PALPATION : Rubbing or deep palpation
or pressure under knees by sitting cross legged or by pillow can cause the clot
break free & embolise. Sudden increase in intrathoracic pressure like
valsalva maneuver can dislodge the clot.
5. COMPRESSION STOCKING : To relieve pain &
swelling and to prevent post thrombotic syndrome, intermittent pneumatic (or
graduated) compression stocking or T.E.D. (Thromboembolic deterent stockings)
which are tighter at foot than higher up the leg are used. They improve venous
flow & may need to be worn for several months or more.
SPECIFIC MEDICINAL TREATMENT :
1. ANTICOAGULANTS : (8)
Heparin : It acts indirectly by activating plasma
Antithrombin III . dose : i/v bolus
7500-10000 IU followed by continues infusion so that 1000-1500 IU/Hr is
maintained.
Deep
SIC injection of 10,000-20,000 U every 8-12 hrs can also be given. The dose is
adjusted so that aPTT becomes twice control value. Heparin treatment should be
maintained for at least 5-7 days. This may cause thrombocytopenia in <5% of
patients. Infrequently these patients may develop arterial thrombosis &
ischemia.
LMWH : They are as effective or even better than
UFH. They also cause antithrombin III dependent inhibition of activated coagulation.
Dalteparins, Enoxapain, Nadoparin are used S/C in
fixed OD/BD doses i.e. 40 mg OD S/C for 6-14 days. Lower incidence of
thrombocytopenia seen (9)(10)(11)
WARFARIN : It is oral anticoagulant acts by
indirectly interfeeling with the synthesis of vit k dependent clotting factors
in liver, 2-10 mg is started during first week of haparin therapy as early as
the first day if aPTT is in therapeutic range. Dose adjusted accordingly to
P.T. INR should be maintained 2-3 times control. Heaprin can then be withdrawn.
- Obese patient undergoing surgery may require
higher doses than non obese .
- Anticoagulation can stop new blood clots from
forming and old ones from growing. However, they
cant’
dissolve the existing clots. The body does this itself over time.
- Duration of anticoagulation :
- Idiopathic thrombus : 6-12 mts.
- Past OP/Secondary thrombus : 3 hrs.
- Secondary episodes of thrombus : at least 1 yr.
5.
Indication :
For patient with proximal D.V.T.
Their use for isolated D.V.T. of calf is controversial
but the patient with calf vein thrombosis should be strictly followed up
because 20-30% of calf thrombosis propagate to the thigh thereby increasing
risk of pulmonary embolism. Also it is identified as cause of embolic stroke
via patent foramen ovale. At least 6 weeks of anticoagulation recommended.
2. THROMBOLYTICS : (12,13,14)
There is no evidence of superiority of
thrombolytics over anticoagulants for D.V.T. However, early administration of
such drugs may accelerate clot lysis, pressure, venous valves and decrease
potential for developing post phlebitic syndrome.(13)(14)
When used heparin is discontinued till aPTT
<_ 1.5 times control
Streptokinase : 250000 IU loading then 100000 IU /
hr for 24 hrs. OR
Urokinase : 4400 IU/kg loading then 4400 IU/hr for
24 hrs. OR
rtPA : 100
mg in 2 hrs.
Heparin restarted when aPTT becomes 1.5 times
control followed by warfarin in the usual manner.
3. INFERIOR VENACAVA (IVC) PLICATION : No more used.
Mechanical interruption of blood flow through IVC.
4. I.V.C. INTERRUPTION :
I.V.C. filters are effective in primary prophylaxis
of thromboembolism in patients with increased risk of bleeding viz. extensive
trauma, visceral, cancer, spinal cord injury etc. There is no benefit to
insertion of a filter paper in patients with free floating thrombi. However
there are some therapeutic indications :
(i)
Contraindication or complications of anticoagulation.
(ii)
Recurrent V.T.E. despite adequate anticoagulation.
(iii)
Chronic recurrent embolism with pulmonary hypertension and pulmonary
embolestomy.
The most commonly used device, Greenfield filter
inserted into femoral or internal jugular vein and has 20 yr efficacy rate 95%
and patency rate 96%.
Anticoagulant therapy is resumed if possible.
Complications :
(i)
Thrombus at the site of insertion
(ii)
Migration of filter
(iii)
Improper filter deployment
(iv) Formation of clot proximal to filter with
proximal propagation and embolization.
(v) Venous insufficiency.
(vi) I.V.C. obstruction.
(vii) Rarely cause M.I., Vessel perforation, pericardial
temponade and arrhythmias.
5. INHIBITORS OF PROPOGATION OF COAGULATION :
These are newer agents : (15)
FONDAPARINUX :
It binds to Antithrombin with highs affinity. Once bound, it evokes conformational changes
in the reactive centre loop of
Antithrombin that enhance its reactivity with factor X a.
Fondaparinux
is a catalytic inhibitor i.e. after promotion of factor Xa it
dissociates from Antithrombin and is available to activate additional
antithrombin molecules.
Adm s/c once daily have predictable anticoagulant
response. Routine monitoring is not required. It is found effective in
prevention of VTE after hip fracture surgery and elective major surgery. It is
also effective in initial treatment of PE. 6.
Contraindicated in renal failure.
IDRAPARNUX
:
It is seemed generation drug with higher affinity
than that of fendaparinux . Once weekly S/C closing is required owing to its
long half-life.
(ii)
Ximelagatran :- It is a prodrug of
melagatran. It is the first oral direct thrombin inhibitor. After absorption
from small intestine, inhibition found to be effective in secondary prevention
of V.T.E. & prevention of VTE after total knee replacement surgery.
Coagulation monitoring is usually not required as it produced predictable anticoagulant
response and prolongation of apTT and INR are not dose dependent.
COMPLICATIONS : (16)
1) Recurrence
2) Post thrombotic (Phlebitic) Syndrome :
Recurrent D.V.T. can cause chronic venous insufficiency from venous
valular destruction resulting in pooling of blood in lower leg. This can result
in pain, swelling, discoloration and sores on leg.
3) P.E. : (17)This is the most common serious
complication. It is this complication that has made D.V.T. a major (18) cause
for concern. This occurs between on in three to one in four cases of D.V.T.A
piece of clot lodged in leg vein breaks off & travels through the body to
the lung where it becomes lodged again causing severe breathing difficulties
accompanied by hypotension or shock, severe hypoxemic respiratory failure,
acute r-sided heart dysfunction or obstruction of pulmonary vasculature that
exceeds 50% (19)(Demonstrated by angiogram or V/Q scan) . This is termed as
fatal P.E. Untreated 1 in 10 die 75% of patients who die of P.E. do so with in
1 hr of onset of symptoms.
4) Chronic thromboembolic pulmonary hypertension :
(20)(21)
This is
associated with progressive dyspnea & progressive heart failure & could
be highly fatal.
5) Stroke :
rarely the clot can dislodge in other organs
including the brain.
PROPHYLAXIS : (22,23)
1. ASPIRIN : Alone is not much useful (24)
2. MECHANICAL COMPRESSION DEVICES : Inermittent compression
pumps is a mechanical device that automatically squeezes the feet and lower
legs. This helps circulation of blood from legs in first few days after
surgery. (25)
3. LMWH : Advantage Over UFH :(26) (27)
(i) Increased binding to plasma proteins or
endothelium in turn leading to
a.
Increased bioavailability b. Predictable anticoagulant response.
(ii) Affinity for macrophages resulting in increase
half life.
(iii) Affinity for platelets and platelet factor 4
binding to osteoblasts
(iv) No monitoring required
(v) No hospitalization required
(vi) Convenient O.D. doses
(vii) Decreased incidence of thrombocytopenia
(viii) Osteopenia Unknown
7.
GENERAL
PREVENTIVE ADVICE : FOR PERSONS AT RISK (15)
FOR TRAVELERS
: (28)
CONCLUSION :
(29) Despite the
availability of effective, prophylactic, therapeutic options ; venous (16)
thromboembolism continues to be under diagnosed and under treated. Awareness
levels are low particularly of medically ill patients to this potentially life
treating killer disease. Though medical (non surgical) patients are at
significant risk of developing (30) DVT in India/other asian countries is
comparable to that in western countries serious challenges for our country in this regard are to find out
prevalence of disease, maintaining standard protocols for its management and having
high suspicion rate to decrease morbidity and mortality from the burden of this
potentially fatal but preventable disease (deep vein thrombosis).
8.
REFERENCES :
(1) Lindblad
B, Stemby NH, Bergqvist D: Incidence of venous thromboembolism verified by
necropsy over 30 years. BMJ
1991;302:709-711.
(2) Goldhaber
SZ, Dunn K, MacDougall RC: New onset of venous Thromboembolism among
hospitalized patients at
brigham and womens Hospital is caused more often by prophylaxis failure than by withholding treatment. Chest 2000;
118: 1680-1684
(3) Anderson
FA Jr, Wheeler HB, Goldberg RJ. A population-based perspective of the
Hospital incidence and
case-fatality rates of deep vein thrombosis and pulmonary embolism. The
Worcester DVT Study. Arch Intern Med.
1991; 151(5):933-8.
(4) Lee
LH, Gu Ko, Heng D. Deep vein thrombosis is not rare in Asia-the Singapore
General
Hospital experience. Ann
Acad Med Singapore. 2002 Nov; 31(6) :761-4.
(5) Agarwala
Sanjay, Bhagwat Abhijit S, Modhe Jagdish. Deep vein thrombosis in Indian
patients undergoing major
lower limb surgery. Indian Journal of Surgery 2003;65(2):159-162.
(6) S. Agarwala, R Wadhwani, JM Modhe et al. Screening for deep
venous thrombosis in postoperative orthopedic patients: Comparison of color
Doppler sonography and contrast venography , Ind J. Ortho 2001 63(2).
(7) Kearon C, Julion JA, Newman TE, Ginsberg JS: Noninvasive
diagnosis of deep venous thrombosis. McMaster Diagnostic Imaging Practice
Guidelines Initiative. Ann Intern Med 1998; 128:663-677.
(8) Charles H. Brown, Bridging Anticoagulation Therapy
Preoperatively for outpatients, Arch Interm Med. 1991; 151:933-938
(9) N. Rajagopalan, Thromboprophylaxis by daltaperin sodium in elective major
orthopedic surgery – A multicentric Indian study. Ind J. Ortho 2003;
37(2).
(10) Samama
MM, Cohen AT, Darmon JY, et al: A comparison of enoxaparin with placebo for
the prevention of venous
thromboembolism in acutely ill medical patients. Prophylaxis in
medical Patients with
Enoxaparin Study Group. N Engl J Med 1999;341:793-800.
(11) Leizorovicz
A, Cohen AT, Turpie AGG, et al: A randomized placebo controlled trial of
dalteparin for the
prevention of venous thromboembolism in 3706 acutely ill medical patients : the
PREVENT medical Thromboprophylaxis study. J Thromb Haemost 2003;1
(Suppl 1): abstract OC396.
(12) Bick RL, Haas S: Thromboprophylaxis and
thrombosis in medical, surgical, trauma, obsteric/gynecologic patients. Hematol
Oncol Clin North Am 2003; 17:217-258.
(13) Buller S. et al. antithrombotic Therapy for
Venous Thromboembolic Disease: The Seventh ACCP Conference on Antithrombotic
and Thrombolytic Therapy. Chest 2004;126:401S-425S.
(14) Jeffrey I. Weitz,Jack Hirsh and Meyer M. Samama. New Anticoagulant
Drugs-The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy.
Chest 2004; 126(3):265S-286S.
(15) Cohen AT: Discoveries in thrombosis care
for medical patients: Semin Thromb Hemost 2002; 28 (Suppl3): 13 –17.
(16) Haas
SK: Venous thromboembolic risk and its prevention in hospitalized medical patients. Semin Thromb Hemost
2002;28:577-584.
(17) Sandler DA, Martin JF: Autopsy
preven pulmonary embolism in hospital patients: are we detecting enough deep
vein thrombosis. J R Soc Med
1989;82:203-205.
(18) Goldhaber
SZ, Savage DD, Garrison Rl, et al. Risk factors for pulmonary embolism-the
Framingham study. JAMA
1983;74: 1023-1028.
(19) Goldhaber SZ, Hennekens CH, Evans DA
et al. Factors associated with the correct antemortem diagnosis of pulmonary
embolism. Am J Med 1982;73:822-826.
(20) Cade
JF. High risk of critically ill for venous thromboembolism. Crit Care Med.
1982;10:448-450.
(21) Vittorio
Pengo, Anthonie W.A. Lensing, Martin H. Prins, et al. Incidence of Chronic
Thromboembolic Pulmonary
Hypertension after Pulmonary Embolism. NEJM 2004; 350(22) : 2257-2264.
(22) Belch
JJ et al. Medically III Prophylaxis. Scott Med J. 1981; 26:115-117.
Nicolaides et. Al. Int
Angiol. 1997;16:3-38.
(23) Clagett GP, Anderson FA, Heit J, et al: Preventions of venous thromboembolism. Chest 1995; 108 (Suppl 1): 312-334.
(24) Todi SK, Sinha S, Chakraborty A.
Utilisation of deep venous thrombosis prophylaxis in medical /surgical
intensive care units. IJCCM 2003;7(2) : 103-105.
(25) Bick RL, Haas S: Thromboprophylaxis and
thrombosis in medical, surgical, trauma, and obsteric/gynecologic patients.
Hematol Oncol clin North Am 2003; 217-258.
(26) Vaitkus
PT, Leizorovicz A, Goldhaber SZ, PREVENT Investigator Group: Rationale and
design of a clinical trial of a
low-molecular weight heparin in preventing clinically
important venous thromboembolism in
medical patients: the prospective evaluation of
dalteparin efficacy for prevention
of venous thromboembolism in immobilized patient
trial (the PREVENT study). Vasc Med
2002;7:269-273.
(27) Mismetti
P, Laporte-Simitsidis S, Tardy B, et al: Prevention of venous thromboembolism
in internal medicine with
unfractionated or low molecular-weight heparins: a meta-analysis of randomized
clinical trials. Thromb Haemost 200; 83 : 14-19.
(28) http://www.guideline.gov/summary/summary.aspx?view_id-1&
doc_id=5893.
(29) Dekker
E, Nurmohamed MT, Heijboer SZ. Prevalence of deep venous thrombosis (deep
vein thromobosis) in
high-risk intensive care patients. Thromb Haemost 1991;65:1348.
(30) Cheuk BL, Cheung BC, Cheng SW. Epidemiology
of venous thromboembolism in a Chinese population. Br J Surg. 2004;91(4):424-8.