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The ankle-brachial index in normal neonates and infants is significantly lower than in older children and adults
The Ankle-Brachial Index in Normal Neonates and Infants Significantly Lower Than in Older Children and Adults By Schmuel
Katz, Anat Globerman, Malka Avitzour, Kfar Saba, Israel
0 Vascular trauma from accidental or iatrogenic causes is becoming more common in children. In early infancy, the most common arterial injuries are caused by diagnostic or interventional cardiac catheterizations. Doppler arterial pressure measurements and the computed ankle-brachial pressure index (ABI) are the most helpful diagnostic modalities in the assessment and follow-up of the ischemic extremity. Because normative ABI data in small children are not available, an ABI of 0.9 or less (based on data obtained from an adult population), is used to indicate limb ischemia in young infants. The purpose of this study was to define the normal values of All in newborns and infants. Materials and Methods: Three hundred and fifty patients were divided into two groups: group 1 (n = 200; male-to-female ratio, 1:l) were full-term (gestational age 40 + 1.3 weeks, surface area 0.22 f 0.02 m2) healthy newborns following uneventful pregnancy and delivery. Group 2 (n = 150) were healthy patients aged 2 weeks to 2.5 years admitted for elective hernia repair. All the patients underwent a complete physical examination, which excluded any cardiovascular pathology. The systolic blood pressure (BP) was measured bilaterally over the brachial, tibialis posterior, and dorsalis pedis arteries. All BP data were obtained in the supine position, using an ultrasonic Doppler flow detector, an appropriately-sized pneumatic cuff and a sphygmomanometer. The chosen cuff size was long enough to completely encircle the circumference and wide enough to cover 75% of the length of the upper arm. The same cuff was applied around the ankle above the malleoli. BP values were expressed as mean + SD in mm Hg. If there was a difference between the BP in the two arms, the higher pressure was used for calculation of the ABI. Resu/ts:The BP measurements in newborns (group 1) were left brachial, 98 f 11; right brachial, 90 f 10 (P < .OOl), left and right tibialisposterior and left and right dorsalis pedis were 83,81, 84, and 82 mm Hg, respectively. The mean computed ABI was 0.88 + 0.11. Fifty eight percent of the newborns had an ABI less than 0.9 (lower limit of normal in adults). The ABI values in patients belonging to group 2 increased with age and surface area. The mean ABI was 1.0, 1.1, and more than 1 .I in patients aged 1, 1.5, and 2 years with surface areas of 0.4, 0.5 and 0.6 m*, respectively (P < .OOl compared with group 1). Conclusion: The normative ABI in newborns and infants is significantly lower than in older children and reaches normal (adult) values during the second year of life. These data may be used as a reference when assessing lower extremity ischemia caused by trauma in young patients. Copyright o 1997 by W. B. Saunders Company INDEX
WORDS:
Ankle-brachial
index,
vascular
trauma.
V
ASCULAR TRAUMA from accidental or iatrogenic causesis becoming more common in children. In early infancy, the most common arterial injuries are causedby diagnosticor interventional cardiac catheterizations.’ Doppler arterial pressure measurementand the computed ankle-brachial index (ABI) are the most helpJournal
ofPediatrIc
Surgery,
Vol32,
No 2 (February),
1997,
pp 269-271
and Tzipora
Is
Dolfin
ful diagnostic modalitiesin the assessment and follow-up of the ischemic extremity.’ This technique allows accurate comparison of the flow to both extremities, but is most helpful if only one extremity is compromised. Becausenormative data in infants and small children are not available, an ABI of 0.9 or less (based on data obtained from an adult population) also hasbeen usedto indicate limb ischemiain the pediatric population.3.4The purposeof this study wasto define the normal ABI values in newbornsand infants. MATERIALS
AND METHODS
Three hundred fifty patients were divided mto two groups. Group 1 (n = 200; male to female ratio, 1:l) were full-term (gestational age 40 -C 1.3 weeks, weight 3374 -C 400 g, and surface area, 0.22 2 0.02 m*) healthy newborns after uneventful pregnancy and delivery. Group 2 (n = 150) were healthy patients aged 2 weeks to 2.5 years admitted for elective hernia repair. All the patients underwent a complete physical examination that excluded any cardiovascular pathology.
Measurementof Blood Pressure The systolic blood pressure (BP) was measured bilaterally over the brachial, tiblalis posterior, and dorsalis pedis arteries. All BP data were obtamed with the patient in the supine posltlon, using an ultrasonic Doppler flow detector, (mode 811 BTS, Park Medical Electromcs, Inc. Aloha OR), an appropriately-sized pneumatic cuff, and a sphygmomanometer (B 546813, Wa-Baum Co Inc. Copiague, NY). The cuff size was long enough to completely encircle the arm and wide enough to cover approximately 75% of the upper arm between the top of the shoulder and the olecranon. The same cuff was applied around the ankle above the malleoli. The bladder width and length of the cuffs were 4 X 9 cm. 5.5 X 11.5 cm, and 8 X 20 cm for newborn, infant, and ctuld, respectively. Measurements were repeated twice at each site. BP values were expressed as mean 2 SD m mm Hg. The ankle-brachial Index was computed by chvldmg the ankle systohc (dorsahs pedis or tibiahs posterior) arterial pressure by brachial systolic arterial pressure. If there was a difference between the BP in the two arms, the higher pressure was used for calculation of the ABI. Student’s t test was used to compare the ABI in the different groups.
RESULTS
The systolic BP measurementsin newborns (group 1) were left brachial, 98 t 11, right brachial, 90 ? 10 From General
the Departmettts Hospital. Sapir
of Pediatric Surgery Medical Center; Kfar
ment of Soczal Medicine. Hadassah Presented at the 27th Annual Surgzcal Associatton, San Diego, Address Pediatric
reprint Surgery,
Medzcal Meeting Calrfornia,
requests to Schmuel Meir General Hospital,
Saba, Israel 44281. Copyright o 1997 by WB. 0022.3168/97/3202-0024$03
Saunders 00/O
and Neonatoiogy, Meir Saba. and the Depart-
Center;
of the May Katz, Sapir
Ein Karem, Ismel. American Pediatric 20-23, 1996. MD, Department Medical Centec
oj Kfar
Cornpuny
269
270
KATZ
(P < .OOl), left and right dorsalis pedis, and left and right tibialis posterior were 83, 81, 84, and 82 mm Hg, respectively. There was no significant difference between the measured arterial pressure over the four arteries of the lower extremities. The mean computed ABI of newborns (group 1) was 0.88 2 0.11. There was no gender difference in the ABI values. The mean ABI of patients aged 1 year (n = 20) in group 2, was 1.07 ? 0.1 (P < .OOl). The ABI values in the other patients belonging to group 2 increased with age and the increasing surface area (Fig 1). The mean ABI was 1.0, 1.I. and greater than 1.1 in patients aged 1, 1.5, and 2 years with surface areas of 0.4, 0.5, and 0.6 m2, respectively. (P > ,001 compared with group 1.) The distribution of the ABI in the different age groups is summarized in Fig 2. Fifty-eight percent of the newborns had an ABI of less than 0.9 (the lower limit of normal in adults). Only 18% had an ABI higher than 1.0. These findings were unchanged during the first 6 months of life. Seventy-eight percent of the patients older than 12 months had an ABI greater than 1 .O and none had an ABI lower than 0.9. The ABI reached normal adult values during the second year of life. DISCUSSION
The ABI values obtained in the present series of normal newborns,infants, and young children are significantly lower than those of older children and adults. Measuring and interpreting BPS in infants and children may be difficult. The accuracy of BP measurementshas been improved by different devices using Doppler or oscillometric principles. The cuff size applied to the limb is of paramountimportancein achieving accuratemeasurements. In adults, measurementof ankle blood pressure
Surface area (m2)
Months 35 + Months
30 +
Surface
area
2. 25..
0.2 .5
0.1
:,/
*e-- --’ Ii.66 0.9
0.95
1.0
Ankle-Brachial Fig 1. Ankle-brachial surface area lm*1 (solid
index line).
(mean1
1.05
1.1
I.105
Index by age
(dashed
line)
and
by
0% Fig 2.’ according
20%
40%
The distribution to age.
of
60% mean
80% ASI
values
ET AL
100% (in
percentages)
with a conventional arm cuff is sufficient. In this study of children, the size of the BP cuffs waschosenaccording to the recommendationsof the Task Force on Blood PressureControl in Children.5In addition, we have found that the ratio between the ankle and arm circumferences in infants and young children is not significantly different from that computed in adults. Therefore, we believe that the low ABI obtained in the very young patients is a true finding and not the result of anatomic factors or technical reasons. Vascular injuries in infants and young children, in contrast to older children and adults, are most frequently iatrogenic.’ Arterial occlusion or spasmmust be considered in patients after catheterization for diagnostic or therapeutic procedures.The younger the patient, the more likely it is that occlusion may occur.6,7Arterial occlusion should be suspectedwhen peripheral pulsesdiminish or are absent and changes in skin temperature, color, and capillary filling of the extremity are noticed. Doppler flow study is particularly helpful when spasmmust be differentiated from mechanicalocclusion.A normal Doppler examination by comparing the flow to the two extremities and by computing the ABI, almost always rules out mechanicalobstruction8 Taylor et all studied 58 children who underwent diagnostic femoral artery catheterization before 5 years of age and found arterial occlusionsin 33% of them. The meanABI of the catheterized legs with arterial occlusion was 0.79. The mean ABI in the uncatheterized legs and the control patients legs were 1.03 and 1.14, respectively. In addition, a significant inverse relationship between ABI and leg growth retardation was found. The meanage of the patients at the time of the study was9 years and the youngest patient was almost6 years old. An ABI of 0.9 or less was indicative of limb ischemia in their series of children. One may hypothesize that the low ABI in very young patients may be attributed to the differential cephalo-
ANKLE-BRACHIAL
INDEX
271
caudal development of the skeletal muscles.” The increase in the muscle mass of the lower extremities with the development of gait. observed during the second year of life, are probably associated with remarkable alterations in blood perfusion to the limb. Therefore, one might expect a correlation between the developmental changes of the lower extremities and the constant increase in ABI during this critical period.
These data should be considered as a reference for surgeons who are called on to examine and assess ischemic legs in infants and young children. The normative ABI in this age group is significantly lower than that of adults. Further flow studies should be carried out in young children with clinical evidence of ischemia, to determine the minimal ABI required for limb viability and the optimal ABI for normal limb growth.
REFERENCES I, O’Nelll JA Jr: Traumattc vascular lessons m Infants and chddren, m Dean RH. O’Nedl JA Jr teds). Vascular Disorders m Childhood. Philadelphia. PA, Lea and Febiger. 1983. pp I8 I - I93 2 Yao ST: Haemodynamlc Surg 57~761-766. 1970
studxs
III pertpheral
arterial dlaease. Br J
3. Flamgan DP, Kelfer TJ, Shuler JJ. et al: Ex.penence with iatrogemc pediatric vascular mJur,es Incidence, etiology. management and results. Ann Surg 198.430-442. I983 4. Taylor LM. Troutman R, Frltclano P. et aI, Late compllcatlons after femoral artery catheterization in children less than five years of age. J Vast Surg I I 297-305. 1990
5 Report on the second Task Force on Blood Pressure Control m Chddren. 1987. Pedlatrlc\ 79 l-23. 1987 6 Richardson D, Fallat M. NagaraJ S. et al: Artertal lqurtes m chddren. Arch Surg I I6 685-690. 1981 7. Mortensson W: Angtography of the femoral artery followmg percutaneous cathetertzatron m Infants and chddren. Acta Radlol 17.58 l-583, 1979 8. Klem MD. Coran AG. Whitehouse WM Jr, et al: Management of mtrogemc arterial InJurIes m Infants and children J Pedmtr Surg I7 933-939, 1987 9. Garn SM. Rt. body s)Le and growth m the newborn. Human Biology 30:X%280. 1953
Katz, Anat Globerman, Malka Avitzour, Kfar Saba, Israel
0 Vascular trauma from accidental or iatrogenic causes is becoming more common in children. In early infancy, the most common arterial injuries are caused by diagnostic or interventional cardiac catheterizations. Doppler arterial pressure measurements and the computed ankle-brachial pressure index (ABI) are the most helpful diagnostic modalities in the assessment and follow-up of the ischemic extremity. Because normative ABI data in small children are not available, an ABI of 0.9 or less (based on data obtained from an adult population), is used to indicate limb ischemia in young infants. The purpose of this study was to define the normal values of All in newborns and infants. Materials and Methods: Three hundred and fifty patients were divided into two groups: group 1 (n = 200; male-to-female ratio, 1:l) were full-term (gestational age 40 + 1.3 weeks, surface area 0.22 f 0.02 m2) healthy newborns following uneventful pregnancy and delivery. Group 2 (n = 150) were healthy patients aged 2 weeks to 2.5 years admitted for elective hernia repair. All the patients underwent a complete physical examination, which excluded any cardiovascular pathology. The systolic blood pressure (BP) was measured bilaterally over the brachial, tibialis posterior, and dorsalis pedis arteries. All BP data were obtained in the supine position, using an ultrasonic Doppler flow detector, an appropriately-sized pneumatic cuff and a sphygmomanometer. The chosen cuff size was long enough to completely encircle the circumference and wide enough to cover 75% of the length of the upper arm. The same cuff was applied around the ankle above the malleoli. BP values were expressed as mean + SD in mm Hg. If there was a difference between the BP in the two arms, the higher pressure was used for calculation of the ABI. Resu/ts:The BP measurements in newborns (group 1) were left brachial, 98 f 11; right brachial, 90 f 10 (P < .OOl), left and right tibialisposterior and left and right dorsalis pedis were 83,81, 84, and 82 mm Hg, respectively. The mean computed ABI was 0.88 + 0.11. Fifty eight percent of the newborns had an ABI less than 0.9 (lower limit of normal in adults). The ABI values in patients belonging to group 2 increased with age and surface area. The mean ABI was 1.0, 1.1, and more than 1 .I in patients aged 1, 1.5, and 2 years with surface areas of 0.4, 0.5 and 0.6 m*, respectively (P < .OOl compared with group 1). Conclusion: The normative ABI in newborns and infants is significantly lower than in older children and reaches normal (adult) values during the second year of life. These data may be used as a reference when assessing lower extremity ischemia caused by trauma in young patients. Copyright o 1997 by W. B. Saunders Company INDEX
WORDS:
Ankle-brachial
index,
vascular
trauma.
V
ASCULAR TRAUMA from accidental or iatrogenic causesis becoming more common in children. In early infancy, the most common arterial injuries are causedby diagnosticor interventional cardiac catheterizations.’ Doppler arterial pressure measurementand the computed ankle-brachial index (ABI) are the most helpJournal
ofPediatrIc
Surgery,
Vol32,
No 2 (February),
1997,
pp 269-271
and Tzipora
Is
Dolfin
ful diagnostic modalitiesin the assessment and follow-up of the ischemic extremity.’ This technique allows accurate comparison of the flow to both extremities, but is most helpful if only one extremity is compromised. Becausenormative data in infants and small children are not available, an ABI of 0.9 or less (based on data obtained from an adult population) also hasbeen usedto indicate limb ischemiain the pediatric population.3.4The purposeof this study wasto define the normal ABI values in newbornsand infants. MATERIALS
AND METHODS
Three hundred fifty patients were divided mto two groups. Group 1 (n = 200; male to female ratio, 1:l) were full-term (gestational age 40 -C 1.3 weeks, weight 3374 -C 400 g, and surface area, 0.22 2 0.02 m*) healthy newborns after uneventful pregnancy and delivery. Group 2 (n = 150) were healthy patients aged 2 weeks to 2.5 years admitted for elective hernia repair. All the patients underwent a complete physical examination that excluded any cardiovascular pathology.
Measurementof Blood Pressure The systolic blood pressure (BP) was measured bilaterally over the brachial, tiblalis posterior, and dorsalis pedis arteries. All BP data were obtamed with the patient in the supine posltlon, using an ultrasonic Doppler flow detector, (mode 811 BTS, Park Medical Electromcs, Inc. Aloha OR), an appropriately-sized pneumatic cuff, and a sphygmomanometer (B 546813, Wa-Baum Co Inc. Copiague, NY). The cuff size was long enough to completely encircle the arm and wide enough to cover approximately 75% of the upper arm between the top of the shoulder and the olecranon. The same cuff was applied around the ankle above the malleoli. The bladder width and length of the cuffs were 4 X 9 cm. 5.5 X 11.5 cm, and 8 X 20 cm for newborn, infant, and ctuld, respectively. Measurements were repeated twice at each site. BP values were expressed as mean 2 SD m mm Hg. The ankle-brachial Index was computed by chvldmg the ankle systohc (dorsahs pedis or tibiahs posterior) arterial pressure by brachial systolic arterial pressure. If there was a difference between the BP in the two arms, the higher pressure was used for calculation of the ABI. Student’s t test was used to compare the ABI in the different groups.
RESULTS
The systolic BP measurementsin newborns (group 1) were left brachial, 98 t 11, right brachial, 90 ? 10 From General
the Departmettts Hospital. Sapir
of Pediatric Surgery Medical Center; Kfar
ment of Soczal Medicine. Hadassah Presented at the 27th Annual Surgzcal Associatton, San Diego, Address Pediatric
reprint Surgery,
Medzcal Meeting Calrfornia,
requests to Schmuel Meir General Hospital,
Saba, Israel 44281. Copyright o 1997 by WB. 0022.3168/97/3202-0024$03
Saunders 00/O
and Neonatoiogy, Meir Saba. and the Depart-
Center;
of the May Katz, Sapir
Ein Karem, Ismel. American Pediatric 20-23, 1996. MD, Department Medical Centec
oj Kfar
Cornpuny
269
270
KATZ
(P < .OOl), left and right dorsalis pedis, and left and right tibialis posterior were 83, 81, 84, and 82 mm Hg, respectively. There was no significant difference between the measured arterial pressure over the four arteries of the lower extremities. The mean computed ABI of newborns (group 1) was 0.88 2 0.11. There was no gender difference in the ABI values. The mean ABI of patients aged 1 year (n = 20) in group 2, was 1.07 ? 0.1 (P < .OOl). The ABI values in the other patients belonging to group 2 increased with age and the increasing surface area (Fig 1). The mean ABI was 1.0, 1.I. and greater than 1.1 in patients aged 1, 1.5, and 2 years with surface areas of 0.4, 0.5, and 0.6 m2, respectively. (P > ,001 compared with group 1.) The distribution of the ABI in the different age groups is summarized in Fig 2. Fifty-eight percent of the newborns had an ABI of less than 0.9 (the lower limit of normal in adults). Only 18% had an ABI higher than 1.0. These findings were unchanged during the first 6 months of life. Seventy-eight percent of the patients older than 12 months had an ABI greater than 1 .O and none had an ABI lower than 0.9. The ABI reached normal adult values during the second year of life. DISCUSSION
The ABI values obtained in the present series of normal newborns,infants, and young children are significantly lower than those of older children and adults. Measuring and interpreting BPS in infants and children may be difficult. The accuracy of BP measurementshas been improved by different devices using Doppler or oscillometric principles. The cuff size applied to the limb is of paramountimportancein achieving accuratemeasurements. In adults, measurementof ankle blood pressure
Surface area (m2)
Months 35 + Months
30 +
Surface
area
2. 25..
0.2 .5
0.1
:,/
*e-- --’ Ii.66 0.9
0.95
1.0
Ankle-Brachial Fig 1. Ankle-brachial surface area lm*1 (solid
index line).
(mean1
1.05
1.1
I.105
Index by age
(dashed
line)
and
by
0% Fig 2.’ according
20%
40%
The distribution to age.
of
60% mean
80% ASI
values
ET AL
100% (in
percentages)
with a conventional arm cuff is sufficient. In this study of children, the size of the BP cuffs waschosenaccording to the recommendationsof the Task Force on Blood PressureControl in Children.5In addition, we have found that the ratio between the ankle and arm circumferences in infants and young children is not significantly different from that computed in adults. Therefore, we believe that the low ABI obtained in the very young patients is a true finding and not the result of anatomic factors or technical reasons. Vascular injuries in infants and young children, in contrast to older children and adults, are most frequently iatrogenic.’ Arterial occlusion or spasmmust be considered in patients after catheterization for diagnostic or therapeutic procedures.The younger the patient, the more likely it is that occlusion may occur.6,7Arterial occlusion should be suspectedwhen peripheral pulsesdiminish or are absent and changes in skin temperature, color, and capillary filling of the extremity are noticed. Doppler flow study is particularly helpful when spasmmust be differentiated from mechanicalocclusion.A normal Doppler examination by comparing the flow to the two extremities and by computing the ABI, almost always rules out mechanicalobstruction8 Taylor et all studied 58 children who underwent diagnostic femoral artery catheterization before 5 years of age and found arterial occlusionsin 33% of them. The meanABI of the catheterized legs with arterial occlusion was 0.79. The mean ABI in the uncatheterized legs and the control patients legs were 1.03 and 1.14, respectively. In addition, a significant inverse relationship between ABI and leg growth retardation was found. The meanage of the patients at the time of the study was9 years and the youngest patient was almost6 years old. An ABI of 0.9 or less was indicative of limb ischemia in their series of children. One may hypothesize that the low ABI in very young patients may be attributed to the differential cephalo-
ANKLE-BRACHIAL
INDEX
271
caudal development of the skeletal muscles.” The increase in the muscle mass of the lower extremities with the development of gait. observed during the second year of life, are probably associated with remarkable alterations in blood perfusion to the limb. Therefore, one might expect a correlation between the developmental changes of the lower extremities and the constant increase in ABI during this critical period.
These data should be considered as a reference for surgeons who are called on to examine and assess ischemic legs in infants and young children. The normative ABI in this age group is significantly lower than that of adults. Further flow studies should be carried out in young children with clinical evidence of ischemia, to determine the minimal ABI required for limb viability and the optimal ABI for normal limb growth.
REFERENCES I, O’Nelll JA Jr: Traumattc vascular lessons m Infants and chddren, m Dean RH. O’Nedl JA Jr teds). Vascular Disorders m Childhood. Philadelphia. PA, Lea and Febiger. 1983. pp I8 I - I93 2 Yao ST: Haemodynamlc Surg 57~761-766. 1970
studxs
III pertpheral
arterial dlaease. Br J
3. Flamgan DP, Kelfer TJ, Shuler JJ. et al: Ex.penence with iatrogemc pediatric vascular mJur,es Incidence, etiology. management and results. Ann Surg 198.430-442. I983 4. Taylor LM. Troutman R, Frltclano P. et aI, Late compllcatlons after femoral artery catheterization in children less than five years of age. J Vast Surg I I 297-305. 1990
5 Report on the second Task Force on Blood Pressure Control m Chddren. 1987. Pedlatrlc\ 79 l-23. 1987 6 Richardson D, Fallat M. NagaraJ S. et al: Artertal lqurtes m chddren. Arch Surg I I6 685-690. 1981 7. Mortensson W: Angtography of the femoral artery followmg percutaneous cathetertzatron m Infants and chddren. Acta Radlol 17.58 l-583, 1979 8. Klem MD. Coran AG. Whitehouse WM Jr, et al: Management of mtrogemc arterial InJurIes m Infants and children J Pedmtr Surg I7 933-939, 1987 9. Garn SM. Rt. body s)Le and growth m the newborn. Human Biology 30:X%280. 1953