|Year : 2016 | Volume
| Issue : 1 | Page : 19-23
Spectrum of Ankle-Brachial Index in Chronic Kidney Disease in Rural Teaching Hospital
Shriharsha Ontenddu1, Sunil Kumar1, Pankaj Banode2
1 Department of Medicine, JawaharLal Nehru Medical College, DMIMS, Sawangi, Wardha, Maharashtra, India
2 Department of Interventional Radiodiagnosis, JawaharLal Nehru Medical College, DMIMS, Sawangi, Wardha, Maharashtra, India
|Date of Web Publication||1-Feb-2016|
Department of Medicine, JawaharLal Nehru Medical College, DMIMS, Sawangi, Wardha, Maharashtra
Source of Support: None, Conflict of Interest: None
Background and Objective: The ankle-brachial index (ABI) is a noninvasive method used to predict subclinical atherosclerosis in patients with chronic kidney disease (CKD). Studies regarding this are lacking in India, especially in a rural setting. Here, we have tried to determine the prevalence of peripheral arterial disease (PAD) by manual ABI, which is a low-cost diagnostic tool than Doppler ABI. Materials and Methods: This is a prospective observational study carried out over a period of 2 years enrolling 240 patients with CKD within the age group of 17-85 years. All patients and controls underwent thorough clinical examination and required laboratory investigation. Statistical analysis was carried out using statistics using the Z-test for the difference in comparison and calculation of P values. Results: The mean age of presentation was 47.91 ± 14.23 with a male preponderance of 161 (67.08%). The relation between hemodialysis (HD) and peripheral vascular disease and its duration were compared which showed significantly lower ABI values in patients who were on HD −0.87 ± 0.05 (manual), 0.90 ± 0.09 (Doppler); off HD: 0.89 ± 0.07 (manual), 0.93 ± 0.07 (Doppler) with P = 0.008 (manual), 0.007 (Doppler), and longer duration of HD (>6 months), showing lower ABI values which were statistically significant ≤6 months: 0.88 ± 0.05 (manual), 0.90 ± 0.10 (Doppler); >6 months: 0.85 ± 0.05 (manual), 0.88 ± 0.06 (Doppler). Conclusion: The correlation of both methods of ABI was compared with different stages of CKD in detecting PAD that showed that both methods were equally effective in detecting CKD in different stages.
Keywords: Ankle-brachial index, atherosclerosis, chronic kidney disease, Doppler, hemodialysis, manual
|How to cite this article:|
Ontenddu S, Kumar S, Banode P. Spectrum of Ankle-Brachial Index in Chronic Kidney Disease in Rural Teaching Hospital. J Integr Nephrol Androl 2016;3:19-23
|How to cite this URL:|
Ontenddu S, Kumar S, Banode P. Spectrum of Ankle-Brachial Index in Chronic Kidney Disease in Rural Teaching Hospital. J Integr Nephrol Androl [serial online] 2016 [cited 2019 Sep 19];3:19-23. Available from: http://www.journal-ina.com/text.asp?2016/3/1/19/175397
| Introduction|| |
Chronic kidney disease (CKD) is a global public health problem. It is estimated that approximately 100,000 new cases of end-stage renal disease develop annually in India which has significant morbidity and mortality.  Patients with CKD are at an increased risk for cardiovascular disease (CVD), and the annual mortality from CVD in such patients is substantially higher than in the general population. , The most common culprit of CVD is atherosclerosis which usually manifest as peripheral arterial disease (PAD), characterized by atherosclerotic occlusive disease of the lower extremities. It has been reported that over one-half of those with PAD remains asymptomatic. However, only there are a few noninvasive diagnostic tests that can reveal the evidence of atherosclerosis in asymptomatic individuals. One such simple, low-cost diagnostic test is the comparison of blood pressure (BP) measurements in the ankle and arm.  The ankle-brachial BP index (ABI), a ratio of the ankle and arm pressures, has been used widely in clinical and epidemiological studies to screen for PAD and is believed to be highly correlated with the PAD of lower extremity; the cutoff point for detecting this at rest is <0.9.  However, ABI has been suggested to be unsuitable for assessing PAD in patients with diabetes, older age, history of intervention for PAD, or advanced CKD. ,, In particular, increased arterial stiffness might interfere with ABI measurements and affect the sensitivity of ABI for detecting PAD among dialysis patients. It is important to establish a screening test for PAD that has sufficient diagnostic value and is safe and inexpensive. In this study, we correlated the prevalence of asymptomatic PAD by manual ABI and noninvasive imaging duplex ultrasonography among all the patients with CKD in different stages.
| Materials and methods|| |
This prospective observational study was carried out in the Department of Medicine of Jawaharlal Nehru Medical College and Acharya Vinoba Bhave Rural Hospital, Wardha, a rural medical college in central India, over a period from September 1, 2012, to September 31, 2014, after approval and acceptance by the Institutional Ethics Committee. All consecutive subjects diagnosed as a case of CKD admitted in the department of medicine were enrolled in the study after due consent.
The basis of diagnosis of chronic kidney disease was duration of the disease (>3 months), anemia, hypertension, and relatively small size kidney on ultrasonography of abdomen.
All subjects admitted to medicine wards diagnosed as having CKD in all age groups were included in the study.
Patients with bilateral filariasis in the lower limb, cellulitis in the lower limb, malignancy in the lower limb, amputated lower limb, and who not willing to give consent were excluded from the study.
Method of collection of data
After informed consent was taken and clinical examination conducted, subjects were screened for various risk factors, including diabetes, hypertension, smoking, and alcohol. Subject's height and weight were recorded to calculate body mass index (BMI), and the ankle-brachial index was calculated manually by Doppler method. All cases were classified into different stages by calculating the glomerular filtration rate by the Cockcroft-Gault formula.
Measurement of the ankle-brachial index
Measurement was done on patients lying flat with the head and heels fully supported, i.e., not hanging over the end of the examination table and after a rest of 5-10 min. The patients were refrained from smoking, heavy exercise, and alcohol drinking for at least 2 h before the examination.
A single observer performed the manual BP measurements in all subjects. He/she consecutively obtained two Doppler readings of systolic pressure, two auscultatory readings of systolic and two of diastolic pressure at the right posterior tibial artery, and final two auscultatory readings of systolic and two of diastolic pressure in the right brachial artery. For the Doppler measurements, the observer used a handheld 8 MHz Aloka Prosound Alpha -7 (20259721), Bangalore, India and for the auscultatory measurements, a standard mercury sphygmomanometer. Cuffs used for the brachial and posterior tibial BP measurements had a bladder size of 12 cm × 22 cm and 15 cm × 31 cm, respectively. An 8 MHz Doppler probe was used for Doppler measurement. Machine Doppler gel was applied over the sensor. After the Doppler device is turned on, the probe was placed in the area of the pulse at a 45° to 60° angle to the surface of the skin. The probe then moved around until the clear signal is heard. The cuff was then inflated progressively up to 20 mmHg above the level of flow signal disappearance and then deflated slowly to detect the pressure level of flow signal reappearance. The maximum inflation was 300 mmHg. The systolic pressure was recorded in both the lower limbs as noted by the highest amplitude of the waveform seen on the monitor of the Doppler machine. Position of the cuff with tubing should be away from the probe as this may interfere with the probe positioning. The detection of the brachial blood flow during the arm pressure measurement was also done by the Doppler method as above, and the systolic BP was noted in both the arms. The cuff was positioned at the ankle proximal two malleoli. The pulse was located with the Doppler probe and the cuff inflated until the pulse was obliterated; the cuff was then deflated and the pressure recorded at the point when the pulse reappeared. ABI was calculated by dividing the average systolic BP of the index ankle artery by the average systolic BP of the index arm. In line with current recommendations, we considered an ABI of 0.9 or less and an ABI of 1.4 or more as possibly indicative of PAD and incompressible arteries, respectively. ,
The individual case data obtained from the study population were transferred to the excel sheet and analyzed further using standard statistical tests. The statistical tests used were Z-test for comparison and calculation of P-values. The software used for analysis was SPSS 17.0 and GraphPad Prism 5.0. The P < 0.05 were considered as the level of significance in this study.
| Results|| |
We enrolled 240 patients with CKD who were age- and sex-matched and the ABI was calculated in all patients. The baseline characteristics of the population are shown in [Table 1]. The mean age of presentation was 47.91 ± 14.23, with a male preponderance of 161 (67.08%). Among the risk factors, diabetes showed the highest prevalence. Percentages of patients in different age groups of <40 years, between 41-60 years and 51-60 years, are shown in [Table 2]. In our study, the mean values of ABI by both manual and Doppler methods between patients on hemodialysis (HD) and off HD show a lower mean ABI value in patients on HD than those on HD: 0.87 ± 0.05 (M), 0.90 ± 0.09 (D); off HD: 0.89 ± 0.07 (M), 0.93 ± 0.07 (D), respectively, and the difference between these two was statistically significant (0.032 [M] and 0.008 [D] S, P < 0.05) [Table 3]. In studying the relation of HD with PAD, it revealed that the mean ABI values were lower in patients who were of longer duration of HD ≤6 months: 0.88 ± 0.05 (M), 0.90 ± 0.10 (D); >6 months: 0.85 ± 0.05 (M), 0.88 ± 0.06 (D) statistically significant difference, P = 0.008 (M), 0.007 (D) [Table 4]. In another way where the relation of both methods of ABI in detecting PAD in different stages of CKD was studied, it showed increased incidence of PAD in the later stages of the disease with lower incidence in stages 1-3. There was no statistical difference when comparing the two methods of ABI in determining PAD in different stages [Table 5] and Graph 1]. Multiple logistic regressions were applied for the association of risk factors with peripheral vascular disease. Independent positive linear correlation was observed among BMI, diabetes, and smoking [Table 6].
|Table 5: Relation of prevalence of peripheral vascular disease with different stages of chronic kidney disease|
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|Table 6: Multiple logistic regression for correlation between peripheral vascular disease and various risk factors|
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| Discussion|| |
There are relatively few noninvasive diagnostic tests that can reveal evidence of atherosclerosis before the development of symptoms. One such simple, low-cost diagnostic test is comparison of BP measurements in the ankle and arm by using manual palpation to measure ABI. This study, following the Heart Outcome Prevention Evaluation study by Ostergren et al., used palpatory method for ankle BP measurement. 
The study of PAD is important in CKD patients not only as a marker of generalized CVD but also as a prognostic tool for a higher mortality rate. The ABI has shown high sensitivity and specificity for the diagnosis of PAD, in comparison with arteriography, the gold standard, and has become an easy and reliable technique for PAD diagnosis. 
Different results have been reported from nondialyzed CKD patients that were diagnosed with PAD by ABI. One of these studies published from Spain, in 102 CKD patients in stages 3-4 not diagnosed with PAD, referred for the 1 st time to a nephrology clinic, their ABI revealed that 32% of the patients suffered from PAD.  This prevalence is similar to that observed in dialyzed patients. 
Here, in our study, patients on HD had a lower mean values of ABI (manual −0.87 ± 0.05, Doppler −0.90 ± 0.09) than those on HD (manual −0.89 ± 0.07, Doppler −0.93 ± 0.07), indicating the increased probability of the prevalence of PAD in this population than patients who were not on HD by both methods of ABI, i.e., manual and Doppler method (P = 0.032 and 0.008, respectively).
The study here showed patients who were on short-term HD (≤6 months) had a lower ABI value (manual −0.88 ± 0.05, Doppler −0.90 ± 0.10) than that who were on long-term HD (>6 months: Manual −0.85 ± 0.05, Doppler −0.88 ± 0.06), indicating that there are greater chances of developing PAD with longer duration of hemodialysis as dictated by the above values that were statistically significant (P = −0.008 and 0.007, respectively).
In this study, a total of 240 patients total patients in stage 5 were 109 patients (45.41%); stage 4 and stage 3 comprised 42.91% and 10.41%, respectively. Less patients were seen in stage 2 accounting for 1.25% and no patients in stage 1. There were more numbers of patients who were positive for PAD in later stages of disease (manual- stage 1-0%, stage 2-0%, stage 3-2.08%, stage 4-23.33%, stage 5-32.93%; Doppler- stage 1-0%, stage 2-0%, stage 3-1.25%, stage 4-18.75%, stage 5-24.17%) and both methods were equally effective in detecting PAD as the difference between the two methods was statistically insignificant. Early stages, i.e., up to stage 2 could not be picked up in in-hospital admissions as many of these patients may have been treated on an outpatient basis as they are usually asymptomatic which did not warrant admission.
As patients were selected according to a predefined protocol to compare the validity of the palpatory method versus gold standard Doppler, so the results cannot be generalized to a population-based study.
| Conclusion|| |
This study demonstrates that PAD is significant in CKD and is easily detected with the ABI technique by the palpatory method in primary care settings. The palpatory method offers a valid, simple, and objective approach that can be used in the physician's office when employed as an initial screening technique for early identification of patients at high risk of morbidity and mortality like CKD.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]