Đánh giá đặc điểm lâm sàng và yếu tố nguy cơ gây huyết khối tĩnh mạch sâu chi dưới ở bệnh nhân suy tim mạn tính: Nghiên cứu luận án Y khoa

MINISTRY OF EDUCATION AND TRAINING MINISTRY OF NATIONAL DEFENSE

MILITARY MEDICAL UNIVERSITY

STUDY OF CLINICAL CHARACTERISTIC AND RISK FACTORS

FOR DEEP VEIN THROMBOSIS OF THE LOWER EXTREMITIES

IN PATIENTS WITH CHRONIC HEART FAILURE

HUYNH VAN AN

Specialty: Cardiovascular Medicine

Code: 62 72 01 41

ABSTRACT OF MEDICAL DOCTORAT THESIS

HANOI 2015

THIS RESEARCH WAS COMPLETED AT THE MILITARY

MEDICAL UNIVERSITY

Faculty advisor:

Assoc. Prof. PhD. NGUYEN OANH OANH

Reviewer 1: Prof. PhD. NGUYEN DUC CONG

Thong Nhat Hospital

TAssoc. Prof. PhD. PHAM NGUYEN SON

Reviewer 2: Prof. PhD. NGUYEN ANH TRI

National Institut of Hematology and Blood Transfusion 108

Military Central Hospita

Reviewer 3: Assoc. Prof. PhD. TRAN VAN RIEP

108 Minitary Central HospitalAssoc. Prof. PhD. HA

HOAN Military Medical University

This thesis will be presented before the University Review

Committee at: …, on …

This Thesis can be searched at:

1. National Library

2. Military Medical University Library

1

PROBLEM POSED

Deep vein thrombosis (DVT) is always one of frequent clinical

issues of hospitalized patients. Pulmonary emboli (PE) an acute

complication of DVT can cause death. Many chronic complications

of DVT such as postthrombosis syndrome and chronic venous ulcers

both damage significantly to the health of patients.

Until now Vietnam, diagnosis and preventive strategies of

DVT for hospitalized individuals in internal medicine or surgery

departments have not been done routinely, especially in patients with

chronic heart failure who usually had high risks of DVT resulted

from either circulatory stasis or restriction of movements.

Currently, there are not many investigations on this interesting

aspect as well as on patients with chronic heart failure (HF).

Clinical signs may be difficult to catch and any health centers

are not equipped with essential diagnose instruments or cannot be

performed intermediately. Thus, we hope this study will reveal real

current evidences and how dangerous of this issue is in Vietnam.

Research objectives:

1. Describe the prevalence, clinical and paraclinical features of deep vein thrombosis at lower extremities using venous

Doppler ultrasound.

2. Identify the risk factors of deep vein thrombosis at lower extremities and its correlation to heart failure severity.

2

1. The subject urgency

DVT is usually seen in hospitalized patients, especially in

patients who have chronic diseases, are motionless or bedridden. This

is an urgent problem recently because of serious impacts to public

health. Furthermore, this disease is not recognized seriously in people

with internal medicine problems. Not only early detection but also

prophylaxis of DVT complications are important issues. In Vietnam,

there are many studies but they unclearly show general approaches,

and there is no thorough research about lower limbs DVT in chronic

HF individuals. So, this problem has been a hard trouble to deal with,

needs many essential solutions and significant realities.

2. New contributions

Study has determined the prevalence of deep vein thrombosis

of the lower extremities in patients with chronic heart failure NYHA

class III/IV and a number of risk factors. Patients with chronic heart

failure are at high risk for deep vein thrombosis and the risk increases

with the functional NYHA III/ IV.

The clinical symptoms of deep vein thrombosis are often

atypical. Hence applying initiative and routine vascular Doppler

ultrasound to diagnose is important in patients with heart failure, who

normally carry higher risk of deep vein thrombosis.

3. Thesis layout

There are 132 pages in this thesis. Besides parts included

such as Problem posed, Conclusion, Recommendation, there are 4

chapters: Overview (38 pages), Objects and methods (19 pages),

Results (30 pages), Discussions (40 pages). There are 43 tables, 14

figures, 4 charts and 143 references (20 Vietnamese, 123 English).

3

Chapter 1

OVERVIEW

1.1. Deep vein thrombosis of the lower extremities

1.1.1. Epidemiology of deep vein thrombosis

In population, the incidence of DVT in the world around

1/1000 adults each year, a more slightly higher in men than in

women, increases with age and reaches 56/1000 per year at the age

of 80. Several studies suggest that at least 23% of the population

have DVT sometime in life.

DVT is considered to be rare in Asian patients. However,

several recent studies have noted an increase in the incidence of DVT

in Asia.

1.1.2. Overview on deep vein thrombosis of the lower extremities

Thrombus formation usually begins in the sinuses after

valves due to the blood stream turbulence which leads to relatively

stagnant blood flow.

The formation of thrombi usually is coordinated by a variety

of factors, including the three basic etiological factors, described by

Virchow: the hypercoagulable blood’s state, blood vessels’ damages,

and blood flow’s stasis.

The risk of DVT increases in the following scenarios:

Immobility: venous blood will flow slowly.

Vein damage: increased risk DVT.

Use female hormones therapy: increases the risk of DVT.

Genetic and acquired diseases: cancer, sepsis, heart failure,

pregnancy, use of oral contraceptives, obesity, over 65 yearold,

making the blood clot, thus increasing the risk of DVT.

4

1.1.4. The workups for diagnosing deep vein thrombosis of the

lower extremities

1.1.4.3. The role of venous Doppler ultrasonography in the diagnosis

of deep vein thrombosis of the lower extremities

In 1986, the ultrasound technique squeeze blood vessels are

first described in diagnosis DVT by Raghavendra.

Duplex ultrasonography uses a combination of two methods:

bmode (modulated luminance) and colorful Doppler techniques.

This is the method used to detect the presence of intravascular echoic

blood clots (volume occupied by blood clots) and used to evaluate

the blood flow (including the shift of blood flow, direction flow, and

the change in respiration).

Color Doppler ultrasound allows to conduct a broad and non

invasive. Assessment color Doppler ultrasound is equal to

compression ultrasound or combine multiple clinical, ddimer testing

and compression ultrasound.

Color Doppler ultrasound is increasingly accepted as a means

of imaging noninvasive, accurate in the case of suspected DVT. The

sensitivity 95% and specificity of 98% are mentioned in many

researches around the world.

Intravenous compression usually causes complete collapse,

while sometimes venous thrombi only against the compressive

forces, or intravascular pressure is not falling. Uncollapsed veins

after compressing is the sole criterion showed venous thrombosis.

Color Doppler ultrasound is routinely used to identify blood vessels,

especially in the deeper sections. Color fills the entire normal veins,

but color flow is diminished or undetected in venous thrombosis.

5

1.2. Heart failure

1.2.1. Epidemiology

At the age from 45 to 54, the rate of HF in males is 1.8/1,000;

4/1,000 at 5564 and 8.2/10,000 at 6574. On average, after ten years

living, the risk rises twofold. HF is popular in patients hospitalized

with HF and the most common HF among above65yearold people.

1.2.3. New York Heart Association Classification of Heart Failure Class I: No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, or dyspnoea. Class II: Slight limitation of physical activity. Comfortable at rest,

but ordinary physical activity results in fatigue, palpitation, or

dyspnoea. Class III: Marked limitations of physical activity. Comfortable at

rest, but less than ordinary activity results in fatigue, palpitation, or

dyspnoea. Class IV: Unable to carry on any physical activity without

discomfort. Symptoms at rest. If any physical activity is undertaken,

discomfort is increased.

1.3.Research about deep vein thrombosis at heart failure patients

1.3.1. Risk factors of venous thrombosis embolism in heart failure

Congestive HF results to an increase the venous pressure,

associated with immobility of patients, will increase the risk of

congestion. At HF patients, the prolonged immobility will results in

slowing blood flow, decrease the ventricle blood output, congest

veins, hypotension, compacted blood, secondary polycythemia which

leads to venous thrombosis.

6

The risk of venous thrombosis will increase as the EF falls

down. But there are some research show that the congestive heart

failure is not a risk factor of venous thrombosis embolism (VTE).

1.3.3. The incidence and the risk of venous thrombosis embolism in

hospitalized heart failure patients

1.3.3.1. Worldwide

Researches all over the world, especially in Europe and

America, record that 1059% congestive HF patients have DVT.

Belch et al. (1981) recorded that 26% patients hospitalized with HF

suffering DVT due to no thrombosis prevention.

Congestive heart failure is an independent risk factor of VTE.

The risk grows greatly when EF decreases.

HF patients easily suffer from VTE and related complications

like PE and right ventricle failure. The research of Piazza et al. shows

that the HF patients is vulnerable subjects from VTE and its

complications. But their research does not distinguish the systole or

diastole HF, or both, and not record about the data of EF.

Ota et al. (2009) had the first research in Japan about the

incidence of DVT at severe congestive HF patients. The result shows

that the Asian also has the risk of suffering DVT as Europe patients.

1.3.3.2. In Viet Nam

INCIMEDI research (2010), the first study in Vietnam about

asymptomatic DVT in hospitalized patients sufferring acute internal

diseases. Dang Van Phuoc et al. recorded that the rate DVT in

hospitalized patients is 21%. The rate of DVT in severe HF patients

with NYHA class III/IV is 24.5%. However, there are only 20% total

of HF patients.

7

Chapter 2

SUBJECTS AND METHODS

2.1. Subjects

Subjects included 136 chronic heart failure patients with New

York Heart Association class III/IV, at Gia Dinh People’s hospital, in

Ho Chi Minh City, from April 1, 2011 to March 31, 2013.

2.1.1. Selection criteria

Aged 18 years or older with New York Heart Association

class III/IV.

Symptomatic or asymptomatic lower extremity DVT

patients.

Agree to participate in study.

2.1.2. Exclusion criteria

History of DVT, PE within the previous twelve months.

Lower extremity DVT occurs in cancer patients following

their therapy, pregnant women or patients suffering from surgery.

Patients who have hematologic problems.

Patients follow mechanism prophylaxis of DVT such as:

compression stockings or intermittent pneumatic compression.

Not accepted to participate in study.

2.2. Methods

Prospective, descriptive study.

2.2.1.5. Subgroup of study

Patients will be confirmed the presence of lower extremity

DVT by color Doppler ultrasound, then they will be clustered into

two subgroups: DVT group and nonDVT group.

2.3. Data analysis

8

Data will be analyzed by SPSS edition 21.0.

The result of study will be presented with 95% confident

interval.

We use Chisquare test to compare, evaluate the difference

between two rate and tstudent test to compare two means. We use

logistic regression model to determine related factors. P ≤ 0.05 is

considered to be statistical significant.

HF patients with NYHA class III/IV

ECG, Chest Xray Complete blood count PT, PT%, aPTT, INR, Fibrinogen NTproBNP echocardiography Ddimer

Lower extremity Doppler ultrasound

NonDVT diagnostic Diagnostic DVT

Risk factors, correlation between DVT and heart failure Clinical, echo evidences of DVT

Objective 1 Objective 2

Figure 2.1: Flow chart of study protocol

9

Chapter 3

RESULTS

3.1. Patient characteristics

Age: 73.5±12.2. NYHA III HF: 70.6%, NYHA IV HF: 29.4%.

3.2. Clinical and subclinical characteristics of lower extremity

deep vein thrombosis in chronic heart failure patients

Table 3.15: The percentage of DVT in heart failure patients

Frequency (n) Rate (%) DVT

Yes 58 42.6

No 78 57.4

DVT only 30 51.7

Combine with SVT 28 48.3

Table 3.18: Clinical symptoms of deep vein thrombosis

Frequency Rate Symptoms (n=58) (%)

Erythema 3 5.2

Pain localized to the site of thrombus 3 5.2

Swelling of the entire leg 3 5.2

Calf > 3 cm thicker than the other calf 3 5.2

Edema Two legs 28 48.3

One leg 1 1.7

Not edema 29 50

10

3.2.3. Sites and properties of deep vein thrombosis

Table 3.21: Sites of deep vein thrombosis

Location Frequency (n=58) Rate (%)

Common femoral vein 19 32.8

Superficial femoral vein 18 31.0

Deep femoral vein 11 19.0

Popliteal vein 32 55.2

Anterior tibial vein 0 0

Posterial tibial vein 1 1.7

Peroneal vein 0 0

Table 3.23: Sites of binding and obstructive level of thrombus

Thrombus Frequency (n=95) Rate (%)

Sites of binding

Root of valve 33 34.7

Bind to wall of vein 62 65.3

Level of obstruction

Complete 8 8.4

Incomplete 87 91.6

11

3.3. Correlation between the clinical and subclinical characteristics

of deep vein thrombosis and chronic heart failure

3.3.1. The clinical and subclinical characteristics comparison between

nonDVT group and DVT group

Table 3.27: The clinical and subclinical characteristics comparison

between nonDVT group and DVT group

NonDVT group DVT group p Index ( X ± SD) (n=78) (n=58) value

Age (year) 73.0 ± 12.8 74.1 ± 11.4 > 0.5

Immobile time (day) 8.0 ± 4.1 7.6 ± 4.1 > 0.05

BMI 22.2 ± 1.3 22.9 ± 1.7 < 0.05

White blood cell (G/l) 14.42 ± 6.97 13.35 ± 6.36 > 0.05

Hematocrite (%) 34.49 ± 8.14 35.93 ± 9.19 > 0.05

Platelet (G/l) 244.42 ± 111.8 224.76 ± 97.96 > 0.05

PT (second) 14.75 ± 1.95 15.38 ± 3.89 > 0.05

PT% (%) 80.09 ± 14.81 78.51 ± 19.47 > 0.05

INR 1.20 ± 0.19 1.26 ± 0.42 > 0.05

aPTT (second) 29.02 ± 4.22 30.58 ± 10.07 > 0.05

Fibrinogen (g/l) 3.85 ± 1.22 4.47 ± 1.87 < 0.05

14358.61 ± 12343.90

13233.43 ± 13589.94

CRP (mg/l) 89.08 ± 80.17 92.75 ± 86.65 > 0.05

NTProBNP (pg/ml) > 0.05

12

4754.37 ± 6733.15

4897.20 ± 6206.26

Ddimer (ng/mL) > 0.05

Ejection Fraction % 51.6 ± 13.9 53.6 ± 14.9 > 0.05

3.3.4. Correlation between deep vein thrombosis and BMI, smoking

Table 3.32: Correlation between deep vein thrombosis and BMI,

smoking

NonDVT DVT group OR (95% CI) Group group (n=78) (n=58) p value

BMI (kg/m2) (n,%)

< 23 64 (82.1) 36 (62.1) 2.79 (1.266.12)

≥ 23 14 (17.9) 22 (37.9) p < 0.01

Smoking (n,%)

No 68 (78.2) 42 (72.4) 2.59 (1.086.24)

Yes 10 (21.8) 16 (27.6) p < 0.05

13

3.3.6. Relationship between deep vein thrombosis and causes of

heart failure

Table 3.36: Relationship between deep vein thrombosis and

causes of heart failure

Causes of heart NonDVT DVT group OR (95% CI)

failure group (n=78) (n=58) p value

Chronic coronary

artery disease (n,%)

no (n=19) 6 (7.7) 13 (22.4) 0.29 (0.100.81)

yes (n=117) 72 (92.3) 45 (77.6) p < 0.05

Rheumatic heart

disease (n,%)

no (n=134) 76 (97.4) 58 (100) p > 0.05*

yes (n=2) 2 (2.6) 0

Hypertension (n,%)

no (n=107) 62 (79.5) 45 (77.6) p > 0.05

yes (n=29) 16 (20.5) 13 (22.4)

COPD (n,%)

no (n=123) 74 (94.9) 49 (84.5) 3.40 (0.9911.65)

yes (n=13) 4 (5.1) 9 (15.5) p < 0.05

* Test Fisher

14

3.3.8. Relationship between deep vein thrombosis and ejection

fraction of left ventricular (EF%)

Table 3.38: Relationship between deep vein thrombosis and EF

patient groups with NonDVT group DVT group p value following EF% (n=58) (n=78)

< 20% (n,%) 0 > 0.05 1 (1.3)

2029% (n,%) 3 (5.2) 4 (5.1)

3039% (n,%) 9 (15.5) 8 (10.3)

4049% (n,%) 24 (30.8) 13 (22.4)

≥ 50% (n,%) 41 (52.6) 33 (56.9)

< 50% (n,%) (n=62) 37 (47.4) 25 (43.1) > 0.05

≥ 50% (n,%) (n=74) 41 (52.6) 33 (56.9)

3.3.9. Relationship between deep vein thrombosis and severity of

heart failure NYHA III/IV

Table 3.39: Relationship between deep vein thrombosis and

severity of heart failure NYHA III/IV

Severity of Non DVT DVT group OR (95% CI)

heart failure group (n=78) (n=58) p value

( NYHA)

NYHA III (n,%) 66 (68.8) 30 (31.2) 5.13 (2.3011.45)

NYHA IV (n,%) 12 (30.0) 28 (70.0) p = 0.0001

15

3.3.10. Logistic regression model

Table 3.40: Logistic regression model

deep vein thrombosis Variables

n = 136 OR p value

Ten age group 1.15 0.340

Age > 75 0.51 0.054

Immobile time 0.87 0.523

BMI ≥ 23 kg/m2 2.79 0.010

Smoking 2.59 0.034

NYHA IV 5,13 0.0001

EF% < 50% 1.19 0.616

Table 3.41: Logistic regression model

Independent variables deep vein thrombosis

n = 136 OR 95% CI p value

Age > 75 0.63 0.281.44 > 0.05

BMI ≥ 23 kg/m2 1.33 0.513.46 > 0.05

Smoking 1.65 0.594.61 > 0.05

NYHA IV 4.51 1.8610.94 0.001

16

Chapter 4

DISCUSSION 4.1. Patient characteristics

In our study, 2/3 patients (70.6%) have HF NYHA III, and

29.4% have HF NYHA IV. The study in Japan have NYHA II, III,

IV HF patients, of which only half of the patients have severe HF.

4.2 Prevalence rate and clinical, ultrasound signs of deep vein

thrombosis in patients with chronic heart failure:

While previous studies showed the prevalence rate of lower

extremity DVT in patients with chronic HF is 11.2% in Japan and

2040% in other countries, our prevalence is 42.6% (58/136

patients). Such a differrence is due to more severe HF in our study

(we included only HF NYHA III and IV patients with the

percentages of 70.6% and 29.4%, respectively). Meanwhile, the

study by Ota et al. in Japan collected all types of HF, including

NYHA II (42.2%), III (26.1%), IV (31.7%) patients, of which only

half of the patients have severe HF.

4.2.2. Clinical symptoms of DVT of the lower extremities

One important sign to identify thrombosis is swelling in one

leg (edema), which is found in 70% of patients. Although leg edema

is quite common among HF patients with DVT, it is not the typical

sign unless it appears only in one leg.

Some particular symptoms include pain and redness at the

abnormal leg, the whole leg is swollen, the perimeter of the leg with

DVT is larger than the normal one by about 3cm, which is only

seen in 3/58 patients (5.2%). Clinical symptoms of DVT are

17

atypical; moreover, patients with chronic HF often have leg cramps

which overwhelmed DVT symptoms.

Many patients with DVT have no or limited symptoms, but a

high frequency of congestive HF signs, such as leg cramps, may

overlap DVT signs.

4.2.3. Location and properties of deep vein thrombosis

4.2.3.1. Distribution of blood clots in deep vein thrombosis

DVT occurs identically in right and left legs. We noted at the

DVT rate of both legs is 32.8% (19/58 patients), often in one rather

than both legs. This is similar to previous studies, both nationally

and internationally.

According to Ota et al., right leg thrombosis account for

44.5%, left one for 33.3%, and both for 22.2% of the total cases. On

the other hand, Goldhaber et al. noted that one leg lowerextremity

DVT is found in 77% of the patients, while that number is 12% for

both legs.

The most common DVT part is the popliteal vein (55.2%),

common femoral vein (32.8%), superficial femoral vein (31%),

deep femoral vein (19%). At each vein, the probability of

thrombosis occurs equally in both left and right leg.

We recorded 100% of patients with proximal vein thrombosis

(over the knees), one patient (1.7%) had more blood clots at the

distal vein (below the knee).

As noted in Samama et al., the rate of DVT is 57.9% in distal

vein, 23.9% in the proximal, and 16.3% in both. According to

Goldhaber et al., 15.2% of the patients have DVT only in the distal

vein; while 36.5% of them have both proximal and distal vein.

18

Pham Anh Tuan et al., reported 100% of DVT in the proximal vein

thrombosis (iliac and femoral vein), which is similar to our study.

4.2.3.2. Location of thrombi and complete occlusion

We recorded that 65.3% of thrombi adhere to the vein wall,

34.7% to the vein valve, but only 8.4% of the thrombi cause

complete occlusion.

The low rate of complete occlusion caused by thrombi is a

fine explanation for the limited symptoms of DVT and the scarcity

of its typical signs, as indicated in the literature.

4.3. The risk factors for deep vein thrombosis in patients with

chronic heart failure

4.3.1. The relationship of deep vein thrombosis with age

In our research group, there is no age difference was

statistically significant (p < 0.05), between the lower extremity non

DVT group and lower extremity DVT group, with the average age of

the DVT group and nonDVT group about 73.0 and 74.1.

We have not found an association between age and DVT. We

divided into three age groups (< 60, 6080, > 80 years), we found no

significant relation between age and DVT with p > 0.05. Similarly,

some researches in Singapore do not recognize the relevance of

statistical significance with DVT and age.

4.3.3. The relationship of deep vein thrombosis with immobile time

Time immobile (number of days in hospital until the venous

ultrasound) of 2 group nonDVT and DVT 8.0 and 7.6, respectively;

no difference was statistically significant with p > 0.05.

As the number of patients is not large, we divided patients

into 5 groups of time increasing immobile time (15, 610, 1115, 16

19

20, ≥ 21 days), we found no correlation statistical significance

between immobile time (number of days in the hospital until the

venous ultrasound) and DVT with p > 0.05. This is different from the

data on the world which show lying motionless in bed longer

increases the risk DVT.

However, through review of 21 studies in the world of

medical DVT performed on patients from 1981 to 2007, we find the

concept and standard of mobility/immobility in each study had a lot

of difference. A variety of parameters used in the definition (level of

activity, time, distance and reason of immobilization) have a very

large margin for each parameter. For example, the user defines the

time change from hour to day closer to 1 month. Moreover, there is

no "gold standard" or no direction in defining standards

immobilization.

Based on the above definitions, we think the ideal way to

evaluate estate concept or campaign should include more parameters

can be measured as time and distance. That's why we choose the

standard estate patients in the study was lying the whole time of the

day (24 hours/day) on the beds, including the implementation of

individuals living in bed and after 57 days inactivity. 4.3.4. The relationship of deep vein thrombosis with BMI

We noted the relevant statistical significance between BMI ≥ 23 kg/m2 and DVT with OR 2.79; 95% CI, 1.26 to 6.12; p <0.01.

Being overweight is a risk factor for recurrence DVT. The risk of

recurrence associated with almost linear increase in body weight.

Obesity is the most highrisk, high risk of recurrence for almost 2

people with a BMI of 40 kg/m2. Compared with normal weight,

20

overweight people have a higher risk of recurrence by 30% and obese

people have a higher risk of recurrence of 60%.

4.3.5. The relationship of deep vein thrombosis with smoking

We noted the relevant statistical significance between smoking

and DVT with OR 2.59; 95% CI, 1.08 to 6.24; p < 0.05.

Ageno et al. gathered 21 casecontrol studies and cohort with a

total of 63552 patients, noted that factor significantly increases the

risk of VTE is smoking (OR 1.18; 95% CI, 0.951.46).

Smoking can affect coagulation condition due to increased

content of fibrinogen. Smoking is the biggest environmental impact are

known to plasma fibrinogen concentration. Smoking increases the

plasma fibrinogen concentration, may contribute to increase rate of

VTE. Conversely, stop smoking quickly reduces plasma fibrinogen.

4.4. The relationship between deep vein thrombosis and chronic

heart failure

4.4.1. The relationship between deep vein thrombosis and left

ventricular ejection fraction

When comparing the relationship between the rate of DVT in

patients with chronic HF and left ventricular ejection fraction, the

result of our study found no statistically significant relation between

high or low level of left ventricular ejection fraction (EF%) and

DVT.

Howell et al. noted the risk of VTE increased when ejection

fraction decreased, patients with ejection fraction less than 20% have

risk of VTE 38.3 times (OR 38.3; 95% CI, 9.6152.5). HF is an

independent risk factor of VTE and the risk significantly went up

when ejection fraction reduced.

21

The combination of congestive HF and VTE is due to slow

flow tends to clot as Virchow mentioned more than a hundred years

ago. There are hypercoagulation in chronic congestive HF,

contributes to venous congestion.

Similarly, Ota et al. also failed to reveal any statistically

significant difference in left ventricular ejection fraction between the

DVT and nonDVT group.

4.4.2. The relationship between deep vein thrombosis and heart

failure causes

We found the statistically significant correlation between DVT

and chronic coronary artery disease, chronic obstructive pulmonary

disease (COPD).

4.4.2.1. The relationship between deep vein thrombosis and chronic coronary artery disease

VTE includes PE and DVT is a common cardiovascular

disease and ranks 3rd after acute coronary syndrome and stroke. The

combination of cardiovascular disease due to atherosclerosis and

VTE was first claimed by Prandoni et al., they observed that the

carotid atherosclerosis plaque is associated with rising risk of VTE

twice.

4.4.2.2. The relationship between deep vein thrombosis and COPD

Patients with HF due to COPD leading to chronic cor

pulmonale. COPD quite popular because of rapid growing incidence

and high mortality. Acute exacerbation of COPD is a common

disease in need of mechanical ventilation support.

22

In a metaanalysis of studies published in Medline from 1966

2003, Ambrosetti recorded about 10% of patients with acute

exacerbations of COPD hospitalization.

4.4.3. Association of DVT with NYHA III/IV heart failure

The rate of DVT in patients in NYHA class IV in our study is

70.0% (28/40 patients), which is higher than that in patients with

NYHA class III, which is 31.3% (30/96 patients) with significantly

statistical difference (p = 0.0001).

Alikhan et al. has reported the rate of DVT in congestive HF is

14.6%, especially high in severe congestive HF (NYHA III: 12.3%,

NYHA IV: 21.7%).

In Japan, Ota et al. has recorded the association between

severity of congestive HF and the rate of DVT. Patients in NYHA

class IV have the rate of DVT highest (NYHA II: 4.4 %, NYHA III:

4.8%, NYHA IV: 25.5%, p < 0.01).

Our study has identified significantly statistical association of

HF in NYHA class IV with DVT. Class IV patients apparently have

greater risk of DVT than those in class III do (OR 5.13; 95% CI,

2.3011.45; p = 0.0001).

By multivariate regression analysis, our study has identified

HF with class IV as an independently risk factor for DVT in lower

extremities (OR 4.51; 95% CI, 1.8610.94; p = 0.001).

Similarly, Ota et al. has concluded that DVT often occurs in

patients with congestive HF and the NYHA functional classification

is a high risk factor (OR 3.74; 95% CI, 1.728.16; p < 0.01). The

NYHA functional classification is an independent predictor of DVT.

23

Causes leading to difference in risk for DVT among the NYHA

functional classification is the higher the severity of HF is, the more

limited daily physical activities are. It is poor activity due to HF that

causes venous congestion, leading to DVT.

CONCLUSION

Our study, which includes 136 patients with chronic heart failure in NYHA class III/IV divided into two groups: DVT group and nonDVT group, has drawn several conclusions: 1. Prevalence, clinical and paraclinical features of deep vein thrombosis at lower extremities using venous Doppler ultrasound Localized symptoms and signs are ambiguous, only 5.2% of patients with DVT has characteristic symptoms and signs of DVT including pain, erythema, swelling in the affected extremity, perimeter of the affected extremity three centimeters greater than the another.

Ddimer is positive in 100% patients with DVT and 93.6% patients without DVT. The positive value of ddimer is not predictive of DVT.

Ddimer is negative in 3.7% patients. All negative cases do

not have DVT. The negative value of ddimer is exclusive of DVT.

Increased fibrinogen in blood concerned significantly with

DVT compared to nonDVT group (p < 0.05).

The prevalence of DVT in patients with chronic HF in

NYHA class III/IV is 42.6%.

Ratio DVT in heart failure patients with NYHA IV (70%) was significantly higher than ratio DVT in heart failure patients with NYHA III (31.3%), p = 0.0001.

24 DVT occurs more often in one leg (67.2%) than in both

(32.8%).

The rate of DVT is similar in both right and left legs, 65.5% and 67.2% respectively. The rate of thrombosis at every part of deep venous system is also similar.

Thrombi in lower extremities is usually at popliteal vein (55.2%), common femoral vein (32.8%), superficial femoral vein (31%) and deep femoral vein (19%).

100% of patients have proximal venous thrombi (above the knee), 1.7% of patients have additional distal thrombi (below the knee).

Thrombi adhere to venous wall (65.3%) more favorably than

to the implantation of valvular cusp on venous wall (34.7%).

Only 8.4% of thrombi cause venous completely obstruction.

2. Risk factors of deep vein thrombosis at lower extremities and its correlation to heart failure severity

BMI ≥ 23 kg/m2 concerned significantly with DVT (OR 2.79;

95% CI, 1.266.12; p < 0,01).

Smoking concerned significantly with DVT (OR 2.59;

95%CI, 1.086.24; p < 0.05).

Heart failure caused by chronic coronary artery diseases concerned significantly with DVT (OR 0.29; 95% CI, 0.100.81; p < 0.05).

Heart failure caused by COPD concerned significantly with

DVT (OR 3.40; 95% CI, 0.9911.65; p < 0,05).

ớ Heart failure patients have high risk DVT and this risk increases with following function NYHA III/IV. HF patients with NHYA IV have higher risk DVT significantly than patients NYHA III (OR 5.13; 95% CI, 2.3011.45) v i p = 0 .0001.