Evaluation of the accuracy of Doppler ultrasonography to rule out the need for aortoiliac arteriography before infrainguinal arterial reconstruction
(Portuguese PDF version)

Cláudio Jacobovicz1, Jorge R. Ribas Timi2, Luís Henrique Gil França3, Henrique Jorge Stahlke Júnior2, Judy Nakahara4

1. Vascular surgeon, Division of Vascular Surgery, Hospital de Clínicas, Universidade Federal do Paraná, Brazil.
2. Doctor. Associate professor, Vascular Surgery, Hospital de Clínicas, Universidade Federal do Paraná, Brazil.
3. Vascular surgeon. Graduate student, Clinical Surgery, Universidade Federal do Paraná, Brazil.
4. Undergraduate student of Medicine, Universidade Federal do Paraná, Brazil.

Correspondence:
Dr. Cláudio Jacobovicz
Rua Gutemberg, 216/61
CEP 80420-030 - Curitiba - PR
Brazil
Phone: (55) 232.0722
E-mail: claudioj@bbs2.sul.com.br

ABSTRACT

Objective: To determine if Doppler ultrasonography could rule out any hemodynamically significant aortoiliac lesion in patients with palpable femoral pulse, thus leading to selective arteriography of the symptomatic lower extremity.

Patients and method: Preoperative evaluation was performed in eighty-two patients who underwent infrainguinal arterial reconstruction in the Division of Vascular Surgery of Universidade Federal do Paraná, Brazil, from January 1999 to December 2000. All patients had preoperative normal femoral pulse in the symptomatic extremity and underwent ultrasonography of the aortoiliac segment to rule out any hemodynamically significant lesion of this segment. The ultrasonography was later compared with the arteriography, considered the gold standard.

Results: For eighty patients, there was agreement between both studies (ultrasonography and arteriography), and for only two, the ultrasonography was inconclusive. Thus, the specificity of the Doppler ultrasonography was 97.56% and the negative predictive value was 100 %. The most important result was the accuracy (97.56%) of the ultrasonography to rule out significant lesions of the aortoiliac segment, when compared with the arteriography.

Conclusion: Infrainguinal arterial reconstruction can be performed in patients who have normal femoral pulse and who only underwent preoperative ultrasonography to rule out any hemodynamically significant lesion in the aortoiliac segment. Thus, it allows a selective arteriography to be performed in the affected lower extremity, providing a faster, safer and more cost-effective preoperative evaluation.

Key-words: Doppler ultrasonography, arteriography, aortoiliac occlusive disease.
Palavras-chave: ultra-sonografia Doppler, arteriografia, revascularização.

J Vasc Br 2004;3(1):5-12

In developed countries, circulatory diseases are the most common causes of morbidity and mortality. This fact is also becoming a reality for developing countries like Brazil.1

With the life expectancy of the population improving significantly in recent years, medical research programs are being developed intensely. Thus, there are improvements in the prophylaxis and treatment of diseases, and consequently, in the quality of life and survival of patients. Along with these changes, there is also an increase in the number of appointments and surgical procedures.2-4

Chronic lower extremity arterial insufficiency is a common disease. Criqui et al. showed that 10% of people over 65 and 20% over 80 present this type of illness to some degree.5 The seriousness of the case depends on the location and extension of the lesion as well as whether or not there is collateral circulation. The symptoms can vary from intermittent claudication to critical limb ischemia. Consequently, lower extremity arterial reconstruction due to occlusive disease is the most frequent surgical procedure performed in arteries by vascular surgeons.6

The diagnosis of lower extremity arterial insufficiency begins with a careful clinical history and a rigorous physical exam. The palpation of arterial pulses is an integral and important part of the physical exam.7 Arteriography is the complementary diagnostic exam that is still considered to be the gold standard. This exam shows morphological and non-physiological alterations, thus allowing for appropriate treatment planning. In spite of its widespread use, it presents a series of disadvantages: it is quite invasive, it can result in complications, and it is expensive.

Due to these inconveniences, vascular imaging studies, that are less invasive, more uncomfortable for the patient and safer, have been introduced into medical practice over the last few decades. These include Doppler ultrasonography, an accessible exam in practically all divisions of vascular surgery. In addition, the exam is non-invasive, poses no risk to the patient and is more cost-effective. Using the Doppler ultrasonography, one can obtain direct anatomical and physiological information about the arterial disease. In addition, color imaging of the blood flow can be obtained, allowing a confident, detailed study of deep arteries, such as the aorta and its branches. 8,9

Patients who present lower extremity arterial insufficiency and who need limb revascularization should be carefully evaluated. Infrainguinal arterial reconstructions should be preferably performed in an aortoiliac segment without significant lesions. If lesions are present, they should be treated previously or concomitantly with the infrainguinal reconstruction. Patients who present undetected significant aortoiliac stenosis and undergo infrainguinal arterial reconstructions have a tendency for early graft thrombosis.10

A combined evaluation based on the palpation of femoral artery pulses and a Doppler ultrasonography to assess potential aortoiliac occlusive disease is particularly crucial. Patients who need an infrainguinal arterial reconstruction could undergo a selective arteriography of the affected extremity preoperatively. The result would be exams with less contrast material needed, which makes it a safer, faster and more cost-effective procedure.

The objective of the present study is to evaluate the need for preoperative arteriography of the aortoiliac segment in patients undergoing infrainguinal arterial reconstruction once their previous physical examination evidenced palpable femoral pulse in the affected extremity and their Doppler ultrasonography ruled out any hemodynamically significant lesion in the segment.

PATIENTS AND METHODS

Eighty two patients who underwent surgery at the Division of Vascular Surgery of Hospital de Clínicas of Universidade Federal do Paraná, from January of 1999 to December of 2000 were included in the study. Initially, all patients admitted to the hospital with lower extremity arterial insufficiency were considered potential candidates for participation in the study. After the initial evaluation, the patients who were included in the study met the following criteria:

1. Patients with initial clinical suspicion of arterial disease in the distal femoral-popliteal segment with an indication for surgical treatment.
2. Patients who, upon physical examination, presented normal femoral pulse in the affected extremity.
3. Patients who underwent a preoperative Doppler ultrasonography of the aortoiliac segment, including color imaging of the entire segment, and Doppler blood flow analysis not evidencing any hemodynamically significant lesion.
4. Patients who underwent preoperative arteriography of the aortoiliac segment with a two-dimensional imaging of this segment.

Patients who did not met the following criteria were excluded from the study:

1. Patients with lower extremity arterial disease, however, without indication for surgical treatment.
2. Patients who, upon physical examination, did not present normal femoral pulse in the affected extremity.
3. Patients who underwent a preoperative Doppler ultrasonography, evidencing hemodynamically significant lesions in the aortoiliac segment.
4. Patients with acute arterial occlusions caused by diseases other than atherosclerosis.
5. Patients who underwent Doppler ultrasonography in other hospital.
6. Patients who underwent arteriographic examinations which did not follow the study protocol.
7. Emergency clinical situations which did not provide conditions to complete the examination protocol.

The examination consisted of a review of the clinical history, a physical exam and an evaluation of the lower extremity arterial circulation with a portable Doppler flowmeter. Clinical history included data about the presence of intermittent claudication and/or pain at rest. Upon physical exam, the lower extremity arterial pulses were evaluated with careful attention, along with possible trophic lesions on these extremities.

Based on the clinical examination, patients were separated into functional categories of the peripheral arterial disease, according to classifications created by the Society for Vascular Surgery and International Society for Cardiovascular Surgery11 (Table 1).

click hereTable 1 - Functional category of peripheral arterial disease
Degree Category Clinic
0 0 Asymptomatic
I 1 Mild Claudication
I 2 Moderate Claudication
I 3 Severe Claudication
II 4 Ischemic Pain at rest
III 5 Trophic Lesion
III 6 Extensive Gangrene

The evaluation using the portable Doppler flowmeter completed the initial examination. The flows of the femoral, popliteal and posterior and anterior tibial arteries were noted, in addition to ankle-brachial index.

Of the 82 patients studied, 60 (73.2%) were men and 22 (26.8%) were women. The age of the patients ranged between 19 and 87, with an average of 65 years (64.9±11,1). The age distribution is displayed in Table 2 below.

click hereTable 2 - Age group
Age group n %
< 40 years old 1 1.2
41-50 7 8.5
51-60 20 24.4
61-70 26 31.7
71-80 24 29.3
> 80 years old 4 4.9

 

The associated diseases and the factors related to atherosclerosis, such as systemic arterial hypertension, diabetes mellitus, smoking, as well as clinical situations related to morbimortality, including coronary disease and cerebrovascular accident, were studied.

The ultrasonographic exams were all performed at the Division Prof. Dr. Elias Abrão of Vascular Doppler Ultrasound at Hospital Universitário Cajurú of Pontifícia Universidade Católica do Paraná (Brazil). This division employs the Image Point model, by Hewlet-Packard, which has a convex transducer (2.5 and 5.0 MHz) for the aortoiliac segment and a linear transducer (3.6 to 8.0 MHz) for femoral arteries.

All arteriographic examinations were performed at the Division of Hemodynamics at Hospital de Clínicas of Universidade Federal do Paraná (Brazil). The Siemens Multistar Pop equipment and the GE (angiomat 6000) equipment were used for the procedure.

Figures 1 and 2 are examples of hemodynamically significant lesions in the aortoiliac segment as determined by the Doppler ultrasound and the arteriography.

click hereFigure 1 - Color Doppler imaging: thrombosis of the left common iliac artery.


thrombosis of iliac artery

click hereFigure 2 - Arteriography: severe stenosis of the left common iliac artery.

For all the patients, ultrasonographic examinations were performed before the arteriography. Thus, by the time of these examinations, imaging physicians did not know the results of the comparative arteriographic examinations of the aortoiliac segment yet.

Once arteriography is considered the gold standard, all the indexes of quality for the Doppler examination were calculated (specificity, sensitivity, accuracy, positive predictive value and negative predictive value). For all of the variables registered in the study, descriptive statistics were used. To evaluate the relationship between dichotomous variables, the Fisher's Exact test was employed, with a significance level of 5%.12-14

RESULTS

In relation to the surgical indication, patients were classified according to the level of ischemia diagnosed as follows (displayed in Table 3).

click hereTable 3 - Surgical indication
Diagnosis n %
Trophic legion 38 46.4
Pain at rest 27 32.9
Disabling Claudication 11 13.4
Aneurysm 4 4.9
* Traumatic AVF 1 1.2
Pseudo- aneurysm 1 1.2
* AVF - Arterial-Venous Fistula

Of the 38 patients who presented a trophic lesion, four were classified in category 6 (extensive gangrene), and 34 in category 5 (trophic lesion), according to the classification established by Rutherford et al..11

Among the 82 patients, eight (9.8%) had already undergone supracondylar or infracondylar amputation of the contralateral extremity.

Table 4 displays the sites for proximal anastomoses of the bypass grafts.

click hereTable 4 - Proximal anastomosis site

Artery n %
Common femoral 60 73.2
Superficial femoral 7 8.5
Deep femoral 1 1.2
Supragenicular popliteal 6 7.3
Branch of aortobifemoral bypass 5 6.1
Femoral-popliteal bypass 3 3.7

Table 5 refers to the sites for distal anastomoses of the arterial bypass grafts.

click hereTable 5 - Distal anastomosis site

Artery n %
Infragenicular popliteal 36 43.9
Supragenicular popliteal 20 24.4
Anterior tibial 7 8.6
Posterior tibial 6 7.3
Fibular 10 12.2
Tibiofibular branch 1 1.2
Pedis 2 2

Although it is considered the first choice in infrainguinal arterial reconstructions, the autologous greater saphenous vein cannot be used in all cases. Table 6 refers to the types of grafts used to perform the arterial bypass procedures.

click hereTable 6 - Grafts

Graft n %
In situ saphenous vein 47 57.3
Reverse saphenous vein 23 28.1
PTFE 11 13.4
Dacron 1 1.2

Of the 11 patients who underwent an infrainguinal arterial bypass surgery with polytetrafluorethylene (PTFE), one patient had the distal anastomosis of the graft performed to the infragenicular artery due to the impossibility of using the ipsilateral or contralateral greater saphenous vein.

Table 7 lists the immediate postoperative complications, considering an interval of 30 days after the operation.

click hereTable 7 - Complications

Complications n %
Supracondylar amputation 5 6.1
Infracondylar amputation 6 7.3
Reintervention 4* 4.9
Infection + graft ligature 2* 2.4
Death 3 3.7
*A patient presenting infection and later graft ligature that required a supracondylar amputation, and another patient who required an infracondylar amputation after reintervention, were considered to have complications that fall under the category of amputation.

Of the three patients who experienced death, all suffered from diabetes mellitus and coronary insufficiency, and two suffered from systemic arterial hypertension.

As regards to the comparison of the Doppler ultrasonography and the arteriography to rule out hemodynamically significant lesions in the aortoiliac segment, there was agreement between the two examinations in 80 patients. In the two remaining patients, the Doppler ultrasonography examinations were inconclusive, as shown in Table 8.

click hereTable 8 - Arteriography vs. Ultrasonography

Arteriography % Ultrasonography %
Patients 82 100 82 100.00
Conclusive 82 100 80 97.56
Inclusive 0 0 2 2.44

Considering arteriography as the gold standard, indexes of quality for the Doppler ultrasonography were calculated in the evaluation of the aortoiliac segment (Table 9).

click hereTable 9 - Indexes of quality

Specificity 0.9756
Sensitivity ---------
Negative predictive value 1.0000
Positive predictive value ---------
Accuracy 0.9756

DISCUSSION

Currently, the greatest objective of vascular surgery is the search for a better quality of life and survival of patients. Increasingly more refined and less invasive techniques are being used to diagnose and treat patients who suffer from occlusive arterial disease. The use of non-invasive complementary examinations such as the Doppler ultrasonography has become almost essential in the diagnosis of vascular diseases, especially arterial vascular diseases. Thus, invasive examinations, which are expensive and pose risks to the patient, such as arteriography, are indicated for only very select cases.

In relation to the presence of lower extremity arterial disease, the diagnosis depends on a complete anamnesis and a detailed clinical examination. The palpation of arterial pulses, especially of the lower extremities, as well as the presence or absence of thrills and/or murmurs should be very carefully evaluated. With this data, it is possible to determine the gravity of the problem, the possible location of the lesion and the initial evaluation for treatment.

In the present study, one of the first criteria for exclusion was the absence of normal arterial pulse in the femoral artery of the symptomatic extremity. Various studies have shown the importance of arterial pulse palpation in patients who suffer from arterial disease. However, there may be some difference among the evaluations of different observers.15 Sobinsky et al. concluded that, even though arterial pulse palpation is an integral and important part of the evaluation of peripheral arterial disease, this data alone should not be the deciding factor for the need to perform suprainguinal or infrainguinal arterial bypasses.7

Patients who suffer from chronic lower extremity arterial insufficiency can have basically three types of disease. The first, which is the focus of the present study, refers to patients who suffer from chronic lower extremity arterial insufficiency and who only present hemodynamically significant lesions in the distal femoral-popliteal segment. These patients generally present with the primary symptoms of arterial insufficiency, ranging from disabling claudication to pain at rest and/or trophic lesion. In these cases, a thorough evaluation of the donor site as well as the host site is necessary in order to guarantee an adequate blood supply. A reliable preoperative evaluation of the aortoiliac segment, performed through non-invasive examinations, would be a faster and more cost-effective procedure, posing fewer risks to the patient and restricting the arteriographic examination specifically to the symptomatic lower extremity.

Traditionally, arteriography is the examination used for the adequate surgical planning of patients who suffer from arterial insufficiency. Considered the gold standard, it also presents a series of limitations in addition to being an invasive, uncomfortable, expensive and risky examination. The rate of risks for local complications ranges between 0.2 and 2%,16,17 and systemic, renal and cardiac complications occur in up to 12% of patients.18,19 It is a purely anatomical examination, which does not supply any type of physiological information, such as the pattern and velocity of the blood flow, nor does it provide hemodynamic data. Since the images registered by the arteriography are two-dimensional, and atherosclerotic lesions commonly located in the posterior wall of the vessels are three-dimensional, the arteriographic examination usually underestimates the level of stenosis caused by the atherosclerotic plaque. Due to these inconveniences, some authors defend the direct manometry to evaluate the hemodynamic significance of aortoiliac lesions. However, this method is also invasive and does not allow the surgeon to define the exact location and extension of the lesions or their eventual treatment.20

The technological development of ultrasonographic examinations allowed for a large-scale evolution in the diagnosis of vascular diseases. Using the Doppler ultrasonography, it is possible to examine the entire lower extremity arterial tree, from the aorta to the pedis and plantar arteries. The examination allows the surgeon to locate, quantify and determine hemodynamically significant alterations in all arterial segments of the lower extremity. Using the B mode, it displays the arterial anatomy, calculates diameters of the different arteries and locates the atherosclerotic plaques while showing their structure. Through a spectral analysis, examining the distribution of the spectrum of flow velocities and determining the physical features of the wave of flow velocity, stenosis can be quantified and the hemodynamics of the different arterial segments can be studied. The color mode provides instant and simultaneous analyses of the average velocities and direction of the flow in the entire vessel, allowing for the evaluation of specific points where the arterial flow is altered. Thus, appropriate spectral analyses can be performed in these points. By using the power mode, which measures the amplitude of the flow signal, it is possible to show slow or peripheral flow and specifically characterize the interface between light and the vessel wall.21,24

There are already some recent studies in which the possibility of performing aortoiliac and lower extremity revascularization surgeries without the use of arteriography is being discussed. These selected patients could undergo preoperative Doppler ultrasonography or other less invasive examinations.25-28

The present study does not aim at completely discouraging the arteriographic examination in the preoperative evaluation of patients who suffer from lower extremity arterial disease. We believe that, in patients who suffer from arterial disease, especially in the distal femoral-popliteal segment, arteriographic examination is the method of choice to determine the exact locations for the performance of anastomoses, especially distal anastomoses. The main interest of the present study is to evaluate the need for aortoiliac arteriography in patients who will undergo infrainguinal arterial reconstruction. In these cases, with a normal femoral arterial pulse in the symptomatic extremity and a non-invasive examination of the aortoiliac segment, these patients could be evaluated preoperatively only with a selective arteriography of the symptomatic extremity. The importance of such a procedure would be to diminish the amount of contrast material in the arteriographic examination, and, as a consequence, its inherent risks. Thus, preoperative arteriography would also be quicker and more cost-effective.

Schneider & Ogawa evaluated the possibility of using selective arteriography in patients who would undergo lower extremity arterial reconstruction. They concluded that, when the ultrasonography evidenced absence of hemodynamically significant aortoiliac lesions, there was 100% agreement between the ultrasonography and the arteriography. Furthermore, they concluded that the selective use of the arteriography in the symptomatic extremity would decrease the time necessary to complete the examination, from 56 to 29 minutes, and that a lower amount of contrast material would be needed (decreasing from 147 to 56 ml).29 It should be noted that the volume of contrast plays a central part in the development of renal and/or cardiac complications, especially in patients who suffer from renal insufficiency or coronary disease.30,31

Francischelli Neto & Luccas evaluated the use of intraoperative prereconstruction arteriography in patients who suffered from infrainguinal occlusive arterial disease and severe ischemia. They concluded that it was a very useful procedure for this type of patient, as it allowed for an appropriate surgical planning and thus increased the rates of arterial reconstruction and limb salvage.32 The intraoperative prereconstruction arteriography appears to be extremely valuable for patients who live in places with difficult socioeconomic situation and in which there are no other diagnostic methods available, such as angiotomography or angioresonance.

In our study, the examination chosen to evaluate the aortoiliac segment was the Doppler ultrasonography. The results were excellent when compared to those of the arteriography. Of the 82 cases studied, there was agreement between the ultrasonography and the arteriography in 80 cases in displaying the absence of hemodynamically significant lesions. For the other two patients, both morbid obese, the examinations were inconclusive. This could have been due to inadequate preparation of the patients for the examination, which consisted of strict fasting for a minimum of 12 hours, the emptying of the bladder, and occasionally, the use of antiflatulents to decrease the quantity of intestinal gases. With these procedures, the probability that the Doppler ultrasonography would indicate absence of any significant lesion in patients who do not present such lesion (specificity) was 97.56%, and the probability that the patient would not present any significant lesion when the examination indicated absence of lesion (negative predictive value) was 100%. Perhaps the most important observation of the present study was the accuracy of the Doppler ultrasonography in relation to arteriography in detecting the absence of hemodynamically significant lesions in the aortoiliac segment. In this study, there was complete agreement between the Doppler ultrasonography and arteriography in 80 out of the 82 cases evaluated, evidencing an accuracy of 97.56%.

In patients who suffer from lower extremity arterial disease and who have a normal arterial pulse in the femoral artery of the symptomatic extremity, the aortoiliac evaluation can be performed through non-invasive examinations, which do not pose risks to the patients. The Doppler ultrasonography, an examination free of risks and more cost-effective, is ideal for this purpose. In the present study, the ultrasonography presented an accuracy of 97.56% for determining the absence of hemodynamically significant aortoiliac lesions when compared to angiography , which is considered the gold standard. The ideal plan is the combination of the ultrasonography for aortoiliac evaluation - ruling out any hemodynamically significant lesion in this segment - with selective arteriography of the symptomatic lower extremity. This provides the patients who will undergo an infrainguinal arterial reconstruction with a preoperative evaluation that is faster, requires less contrast material, and consequently poses fewer inherent risks for the patient, especially renal and cardiac risks.

CONCLUSION

This study leads to the conclusion that patients who require infrainguinal arterial reconstruction can undergo surgery without the need for arteriography of the aortoiliac segment, given that they present a normal femoral arterial pulse in the symptomatic extremity, and that the Doppler ultrasonography ruled out any hemodynamically significant aortoiliac lesions.

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