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Comparison between the outcome assessment of the clinical treatment in patients with intermittent claudication due to bilateral femoropopliteal obstruction versus aortic obstruction
(Portuguese PDF version)

Manoel Augusto Lobato dos Santos Filho, Ruben Miguel Ayzin Rosoky, Daniella Ferraro Fernandes Costa, César Biselli Ferreira, Nelson Wolosker, Pedro Puech-Leão^*

* Vascular Surgery, Department of Surgery, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (USP), SP, Brazil.

Correspondence:
Manoel Augusto Lobato dos Santos Filho
Rua Fradique Coutinho, 66/803, Pinheiros
CEP 05416-010 - São Paulo, SP, Brazil
Phone/Fax: +55 (11) 3085.0807
E-mail: manoellobato@hotmail.com, manoellobato@yahoo.com.br, manoellobato@ig.com.br

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ABSTRACT

Objectives: Intermittent claudication is an early clinical manifestation of peripheral arterial occlusive disease. Its evolution is usually mild with clinical treatment. However, some patients do not show improvement in symptoms and may even deteriorate. The purpose of this study was to verify if there is any difference in the outcome assessment of the clinical treatment regarding the location of the artery obstruction.

Methods: A total of 212 patients with peripheral arterial occlusive disease and intermittent claudication who underwent appropriate clinical treatment were assessed and classified into two groups: group AO (aortic obstruction) and group FP (bilateral femoropopliteal obstruction).

Results: Outcome assessment was based on the walking distance at a graded load treadmill test, performed at the first and last assessments. At the end of the follow-up period, four (4.9%) group AO patients walked less than 50 meters, and one (1.2%) patient presented ischemia at rest. While two (1.5%) group FP patients walked less than 50 meters, and four (3.1%) patients presented ischemia at rest. The final distance in meters shows a statistically significant improvement in both groups (Group AO P = 0.003 and Group FP P < 0.0001), group FP presenting better results (P = 0.011).

Conclusion: We observed that patients significantly improved in both groups. Furthermore, group FP patients progressed better than group AO patients.

Key-words: intermittent claudication, popliteal artery, aorta.

J Vasc Br 2005;4(2):137-42

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Intermittent claudication (IC) is often the first clinical manifestation of arterial ischemia of the lower limbs.^1,2 It is characterized by muscular pain with physical activity, which is attenuated at rest. The pain is reproducible when conditions of distance, speed, and slope angle that generate it are maintained.²

IC has a potentially benign character, due to the low risk of evolution to severe ischemia and limb loss, and also due to a good possibility of improvement in symptoms.^3-6 For that reason, the clinical treatment is considered adequate and usually used as a first therapeutic alternative.^7,8 However, a significant number of patients develop major limitations for everyday activities, due to symptoms worsening, even when clinical treatment is correctly performed.^4,5 In 5 years' time, approximately 25% of claudicant patients have their clinical status worsened. Of these, 5% progress to limb amputation.^1,3

Several predictive factors of morbidity and mortality of IC are well identified in clinical studies.⁹ Among the most studied factors are the diabetes mellitus,¹⁰ dislipidemia, hypertension,¹¹ dialytic renal insufficiency,¹² smoking,¹³ coronary artery disease,¹¹ and the ankle-brachial index.¹⁴

Whether the location of arterial obstructions influences the clinical treatment outcome is still not clear.^15,16

The aim of this study is to verify if there is a difference in the clinical treatment outcome in patients with aortic and femoropopliteal obstructions.

PATIENTS AND METHODS

We prospectively studied 212 patients with IC. All patients receiving care at the vascular surgery outpatient clinic from 1994 to 2002 were consecutively included, as well as those who had only claudication as a limitation for doing physical activities. Patients with previous vascular surgeries and co-morbidities that limited physical activity were not included in the study. Diagnosis was made through clinical observation and duplex scan. Patients were divided into two groups, according to the level of the arterial obstruction: group AO, with 81 individuals who presented aortic obstruction, and group FP, with 131 patients who presented bilateral femoropopliteal obstruction.

At admission, all patients were told to control the risk factors, avoid smoking (when applicable), and submit to a physical training that consisted of daily sessions, not supervised, in which the patients walked and interrupted their walking due to near-maximal pain. After total remission of pain, the cycle was repeated at a 1-hour interval.

Every 6 months after admission, patients had their pulses reexamined and were instructed to maintain the treatment according to initial guidance.

In all follow-up visits, patients had their walking distance measured in the progressive load treadmill exercise test.¹⁷ Measurements at admission and at last visit were compared.

Finally, in each group, evolutions of all patients were stratified, according to the comparison. Thus, the increase in the walking distance in at least 20% in relation to the initial distance was arbitrarily considered as an improvement. The reduction in the walking distance in at least 20% in relation to initial distance was considered as a worsening. Other variations were classified as stable.

Mean age of patients in group AO was 59.2 years, and there were 86.4% smokers, 60.5% hypertensive patients, and 21% with diabetes. Mean age of patients in group FP was 64.7 years, and there were 74.9% smokers, 72.5% hypertensive patients, and 25.1% with diabetes. The distribution of risk factors for each group can be seen in Table 1.

Table 1 - Associated factors

	Group AO		Group FP
Factors	mean	%	mean	%	P
Number of patients	81	38.2	131	61.8
Age (mean/variation)	59.2/24-81		64.7/23-85		0.008*
Males	55	67.9	79	60.3	0.333
Females	26	32.1	52	39.7
Diabetes mellitus	17	21.0	33	25.1	0.593
Diabetes mellitus I	9	11.1	9	6.9
Diabetes mellitus II	8	9.9	24	18.3
Smoking	70	86.4	98	74.9	0.311
Stopped smoking	32	45.7	47	47.9
Arterial hypertension	49	60.5	95	72.5	0.095
Time of clinical history	747 days		870 days		0.145*
Walked < 50 m at onset	3	3.7	7	5.3

* Statistical test: Mann-Whitney U.
Group AO - patients with aortic obstruction.
Group FP - patients with bilateral femoropopliteal obstruction.

 

Mean time of initial clinical history among patients in group AO was 747 days, and in group FP, 870 days. Mean follow-up time among patients in group AO was 527 days, and in group FP, 537 days (17.7 months).

For statistical calculation, we used SPSS 11.0.0 and SigmaStat for Windows® 2.03, with a significance level of 0.05. For comparison between groups, Mann-Whitney U and univariate analysis were used. To evaluate treatment response in each group, the paired t-test was used, and to compare the clinical evolution between both groups, the chi-square test was used.

RESULTS

Data related to follow-up time and mean initial and final walking distances of each group are in Table 2.

Table 2 - Possible risk factors

	Group AO		Group FP
	Variation	Mean	Variation	Mean	P
Follow-up time in days	14-1,631	527	35-1,582	537	0.712 *
Initial distance in meters	10-650	200	10-650	217	0.316 *
Final distance in meters	0-1,000	305	0-1,000	401	0.011 *
Improvement in meters	105		184		AO P = 0.003 † FP P < 0.0001 †

* statistical test: Mann-Whitney U.
† statistical test: Paired t-test.
Group AO - patients with aortic obstruction.
Group FP - patients with bilateral femoropopliteal obstruction.

 

At the beginning of the study, only three (3.7%) patients with aortic obstruction and seven (5.3%) patients with femoropopliteal obstruction walked less than 50 meters. At the end of the follow-up, four (4.9%) patients in group AO walked less than 50 meters, and one (1.2%) patient presented ischemia at rest. Regarding group FP, two (1.5%) patients walked less than 50 meters and four (3.1%) patients presented ischemia at rest.

We can see in Table 2 that the mean follow-up time and initial walking distances in both groups are similar (P = 0.712 P = 0.316). Final distance in meters shows a statistically significant improvement in both groups (Group AO p = 0.003 and Group FP P < 0.0001), which is higher in group FP (P = 0.011). .

Table 3 shows the clinical evolution of patients in a mean period of 17.7 months of clinical treatment.

Table 3 - Clinical evolution along time

	Group AO		Group FP
Evolution	n of cases	%	n of cases	%
Improvement	33	40.7	75	57.3
Stable	22	27.2	35	26.7
Worsening	26	32.1	21	16.0
Total	81	100.0	131	100.0

* statistical test: chi-square.
Group AO - patients with aortic obstruction.
Group FP - patients with bilateral femoropopliteal obstruction.
Χ² =8.551.
P = 0.014.

 

It can be seen that the group of patients with bilateral femoropopliteal obstruction presented a statistically better evolution than the group of patients with aortic obstruction.

Groups are similar in relation to gender (P = 0.333), smoking (P = 0.311), stop smoking, arterial hypertension (0.095), diabetes (P = 0.593), follow-up and clinical treatment time (P = 0.712), and initial walking distance (P = 0.316), but different in relation to age (p = 0.002). Mean age in group FG was higher. However, when evolutions paired by age were analyzed (more than 65 years old and less than 65 years old), there was no statistical difference (P = 0.191).

DISCUSSION

It is known that the evolution of chronic arterial obstructions in lower limbs is most of the times favorable when clinically treated.^1,3,5,18 Several predictive factors^3,11-13 are related to cases in which the outcome is unfavorable. In this study, we studied the importance of the obstruction site on the prognosis of patients with peripheral obstructive arterial disease (POAD).

We chose to study patients with aortic and bilateral femoropopliteal obstruction, since those groups are probably the most advanced stages of the chronic obstructive arterial disease in those respective territories. For this reason, we did not include patients with unilateral aortoiliac or unilateral femoropopliteal obstructions.

When initial and final walking distances are analyzed (Table 2), a significant improvement can be seen in both groups. Patients with aortic obstruction (AO) had an improvement of 105 meters in average, equivalent to a mean increase of 52.5% in the walking distance (P = 0.003). Patients with bilateral femoropopliteal obstruction had an improvement of 184 meters in average, equivalent to a mean increase of 84.7% in the walking distance (P < 0.001). These data show that the clinical treatment has a good effect on both segments. Nevertheless, it is higher in group FP (P = 0.011), despite mean age being higher.

Similarly, stratification of patients according to vascular evolution (improvement, stable or worsening) shows a more favorable evolution of claudicant patients with femoropopliteal obstruction (P = 0.014). This is probably due to a larger ischemia territory in patients with aortic obstructions and also due to the fact that femoropopliteal obstructions are preferentially located at the adductor canal (Hunter's canal),¹⁹ distally to the deep femoral branch, which plays an essential role in the formation of the collateral circulation in lower limbs. That is why the collateral circulation developed during femoropopliteal obstructions could be more abundant when compared to the collateral network formed during aortic obstructions.^20,21

However, the group of patients with aortic obstruction may have some patients with associated femoropopliteal occlusion, which could worsen the performance and mean results in group AO as a whole.

Several factors seem to be related to the efficiency of the clinical treatment in those patients.²² It is believed that physical exercise favors the formation of new collateral vessels,^23,24 the increase in blood flow,²⁵ the production and release of the nitric oxide, causing more vasodilatation,^26,27, and the optimization of the enzymatic metabolism and oxygen consumption.^28,29 Moreover, exercise training increases HDL (high-density lipoprotein) levels, reduces triglyceride levels,³⁰ controls blood pressure levels,³¹ and mitigates the acute inflammatory response to the vascular endothelium.^32,33

We conclude that the location of the arterial lesion has a relation to the IC prognosis. Although the clinical treatment has great efficacy in both groups, patients with femoropopliteal obstructions present a more remarkable improvement than their pairs with aortic obstructions.

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