BRUSH UP YOUR BASIC SCIENCE
DOPPLER ULTRASOUND IN VASCULAR SURGERY D. E. STRANDNESS, JR Department of Surgery, University of Washington, Seattle Doppler ultrasound was first introduced into the study of arterial and venous disorders in 1966. The devices currently used in clinical practice are continuous wave systems which, in their simplest form, are pocket-sized units. Instruments with the capability o f distinguishing the direction of flow are also available. The signal may be ptocessed for audio use, o r an analogue recording can be made o f the Doppler frequency shift. The described clinical information will, in large part, dictate the type of equipment used.
ACUTEARTERIAL OCCLUSION INTERRUPTION of the arterial flow from whatever cause will produce a fall in the blood pressure distal to the occlusion. This can be measured with the velocity detector as shown in Figure I. For suspected arterial injury, the following information has been found useful : ( i ) an ankle systolic pressure lower than that in the arm or opposite limb is certain evidence of occlusion; (ii) pressures of 40 mm H g or lower signify very poor perfusion and are commonly associated with rest pain ; (iii) surgical correction, if complete, will bring the pressure to normal; and (iv) the pressure measurements are a good index of collateral flow about the obstruction.
equal to that in the arm; (ii) ankle pressures greater than 50% of those in the arm are observed with single segment occlusions ; (iii) pressures less than one-half of those in the arm occur with multiple levels of disease (Figure 2 ) ; (iv) rest pain, tissue necrosis, or both, are commonly observed with pressures helow 40 mm H g ; (v) if the ankle pressure
CHRONIC ARTERIAL OCCLUSION Peripheral.-The diagnosis may be made and the extent assessed of lesions involving the limb arteries by measuring the ankle systolic pressure and determining segmental limb gradients by the four cuff technique. The measurements at the ankle can also be made
Reprints: D. E. Strandness, jr, M.D., Professor of Surgery, Department of Surgery, University of Washington, Seattle, Washington 98195.
AUST.N.Z. J. SURG., VOL.47-N0.
I,
FEBRUARY, 1977
the velocity patterns in all the major arteries and veins of the upper and lower extremities. (C:ourtesy o f Medsonics, 340 Pioneer Way, P.0. Box RI, Mountain View. California 94042.) 115
DOPPLER ULTRASOUND
falls after mild exercise, this is abnormal; and (vi) direct arterial surgery will improve distal pressure and flow to the extent to which the disease has been corrected. These measurements can be used to follow the progress of collateral artery development and evaluate the success of the arterial reconstruction (Figure 3). Extracranial.-Atherosclerosis of the carotid bifurcation produce symptoms of transient cerebral ischmnia or completed stroke by
STRANDNESS
the test is positive in at least 95% of cases. If the test is negative, it most definitely does not rule out the presence of a small plaque which may be the source of emboli. ACUTEVENOUSTHROMBOSIS AND THE POSTPHLEBITIC SYNDROME Whereas the symptoms and signs of peripheral arterial occlusion are often specific and helpful clinically, this is usually not the case with deep vein thrombosis. ~h~ problem is that even when symptoms and signs are present, they are not specific, and the condition may be confused with a variety of other diseases. While contrast venography remains the diagnostic gold standard, the Doppler may be used to assess the major deep veins from the level of the posterior tibia1 vein at the ankle to the external iliac vein in the groin. Venous thrombosis is detected by one of two findings: (i) absence of a venous flow signal where it is normally heard, even with compression of the limb distal to the transducer.
FIGURE 2 : Relationship between the ankle systolic pressure (expressed as Yo of the brachial) and the extent of arterial occlusion proven by arteriography. (From Carter, S.A. (19691, .7. Amer. med. Ass., 207: 1869.)
either the release of emboli or a reduction in hemispheric blood flow by a high-grade stenosis or occlusion. By using a directional Doppler, it is possible to detect hanodynamically significant stenoses or occlusions of the internal carotid artery by noting the direction of flow in the supraorbital artery and evaluating the effects of temporal artery compression. Normally, flow is outward from the skull via the ophthalmic artery, with temporal artery compression resulting in augmentation of that flow. When the internal carotid artery is narrowed by more than half of its diameter, the flow is reversed in the ophthalmic artery, with temporal artery compression resulting in a marked reduction or cessation of flow in the supraorbital artery. If the internal carotid artery is occluded or has a greater than 50% narrowing of its diameter, I 16
FIGURE3 : The changes in the ankle blood pressure response that occurred after common femoral endarterectomy were secondary to disease progression. The problem was detected by both a reduction in resting ankle pressure and its response to exercise.
This is normally called augmentation of flow ; and (ii) the presence of a continuous venous flow signal which is unaffected by a deep inspiration or a Valsalva manceuvre. The continuous flow signal means that venous blood is being diverted around areas of occlusion via collateral vessels which are not influenced to AUST. N.Z. J. SURG.,VOL.47-No.
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FEBRUARY, 1977
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the same degree by the pressure changes that occur in the abdomen and are associated with respiration. The accuracy of this test has varied a great deal, depending upon the experience of the investigator. If the test is completely performed and identical sites on each limb are compared, the false-positive and false-negative incidence should not exceed 10%. This compares favourably with the results of plethysmography i n this field. If the valves of the superficial, deep, or perforating veins are incompetent, this is easily assessed with the velocity detector. Normally, any nianceuvre which increases proximal venous pressure, such as a Valsalva manceuvre or proximal limb compression, will not result in retrograde flow through the valves. Any reversal of blood flow by any of these pressure changes signifies valvular incompetence-the hallmark of venous damage. Since the super-
FIGURE 4 : Ultrasonic arteriogram demonstrating two
stenoses of the internal carotid artery as verified by contrast arteriography.
ficial, deep, and perforating veins can be selectively examined, it is possible to distinguish primary varicose veins from those occurring secondary to disease of the deep venous system. THEFUTURE While the application of continuous wave, direction-sensing devices to clinical problems will continue to be explored and expanded, the AUST. N.Z. J. SURC.,VOL. 47-No.
I, FEBRUARY, 1977
coming era will be concerned with pulsed ultrasonic systems that can be used for arterial imaging and measurement of flow from discrete points along the sound beam (Figure 4). These methods will soon be available for more widespread use and application.
RECOMMENDED REFERENCES STRANUNESS, D. E., JR, SCHULTZ,R. D., SUMNER, D. S. and RUSHMER,R. F. (1967), Ultrasonic flow detection: A useful technique in the evaluation of peripheral vascular disease, Anzer. J . Surg., 113: 311. An account of the technique and the different clinical situations in which it may be used. NIPPA,J. H., HOKANSON, D. E., LEE, D. R., SUMNER, D. E., JR (I975), PhaseD. S. and STRANDNESS, rotation for separating forward and reverse blood velocity signals, IEEE Trans. on Sonics and Ultrason., SU-22/5 : 340. A description of the latest advances in the development of a direction-sensing Doppler system for use in peripheral arteries and veins. BARNES, R. W., BONE, G. E., REINERTSON,J., HOKANSON,D. E., SLAYMAKER, E. E. and STRANDNESS, D. E., JR (1976), Noninvasive carotid angiography. Prospective validation by contrast arteriagraphy, Surgery, 80: 328. The latest results with ultrasonic imaging a s compared with contrast arteriography are reviewed. CARTER,S. A. (1969), Clinical measurement of systolic pressures in limbs with arterial occlusive disease, J . Amer. med. Ass., 207: 1869. This excellent article reviews the relationship between chronic arterial occlusion and its effects on ankle systolic pressure. YAO, S. T. (1970), Experience with the Doppler ultrasound flow velocity meter in peripheral vascular disease, in Gillespie, J. A. (Ed.), Modern Trends in Vascular Surgery, I, Appleton-Century-Crofts, New York. This report reviews the experience a t St Mary’s Hospital in London, England, with the Doppler instrument. CARTER,S. A. (I972), Response of ankle systolic pressure to leg exercise in mild or questionable arterial disease, N . Engl. J . M e d . , 287: 578. This article demonstrates how . measuring limb blood pressures after exercise can detect stenoses which are insignificant when the subject is at rest. BONE,G. E. and BARNES,R. W. (1976), Limitations of the Doppler cerebrovascular examination in hemispheric cerebral ischzmia, Surgery, 79 : 577. LYE, C. R., SUMNER,D. S. and STRANDNESS, D. E., JR (1976), T h e accuracy of the supraorbital Doppler examination in the diagnosis of hemodynamically significant carotid occlusive disease, Surgery, 79: 42. T h e above two articles review the results of Doppler examination in the detection of significant internal carotid artery disease.
117
STRANDNESS
D O P P L E R ULTRASOUND
D. E., J R and SUMNER,D. S. (1975), STRANDNESS, Ultrasonic Techniques in .Angiology, Hans Huber Publ. Co., Berne, Switzerland. This monograph reviews the use of the ultrasonic velocity detector in the evaluation of peripheraI arterial and venous disorders as well as the extracranial arterial system. STRANDNESS, D. E., JR (1975)~ Ultrasound and plethysmography in the diagnosis of acute
venous thrombosis in prophylactic therapy of deep vein thrombosis and pulmonary embolism, D H E W Publ. NO. ( N I H ) 76-866. This publication, obtainable from the National Institutes of Health in Washington, D.C., reviews the entire field of acute venous thrombosis from the standpoints of ztiology, detection, treatment, and prophylaxis.
English, which can express the thoughts of Hamlet, or the tragedy of Lear, has no words for the shiver and the headache. It has all grown one way. The merest schoolgirl, when she falls in love, has Shakespeare or Keats to speak her mind for her; but let the sufferer try to describe a pain in his head to a doctor and the language runs dry. There is nothing ready for him. H e is forced to coin words himself, and, taking his pain in one hand, and a lump of pure sound in the other . . . crush them together that a brand new world in the end drops out. Virginia Woolf, On Being Ill, 1947.
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AUST. N.Z. J. SURG.,VOL. 47-No.
I,
FEBRUARY, 1977
DOPPLER ULTRASOUND IN VASCULAR SURGERY D. E. STRANDNESS, JR Department of Surgery, University of Washington, Seattle Doppler ultrasound was first introduced into the study of arterial and venous disorders in 1966. The devices currently used in clinical practice are continuous wave systems which, in their simplest form, are pocket-sized units. Instruments with the capability o f distinguishing the direction of flow are also available. The signal may be ptocessed for audio use, o r an analogue recording can be made o f the Doppler frequency shift. The described clinical information will, in large part, dictate the type of equipment used.
ACUTEARTERIAL OCCLUSION INTERRUPTION of the arterial flow from whatever cause will produce a fall in the blood pressure distal to the occlusion. This can be measured with the velocity detector as shown in Figure I. For suspected arterial injury, the following information has been found useful : ( i ) an ankle systolic pressure lower than that in the arm or opposite limb is certain evidence of occlusion; (ii) pressures of 40 mm H g or lower signify very poor perfusion and are commonly associated with rest pain ; (iii) surgical correction, if complete, will bring the pressure to normal; and (iv) the pressure measurements are a good index of collateral flow about the obstruction.
equal to that in the arm; (ii) ankle pressures greater than 50% of those in the arm are observed with single segment occlusions ; (iii) pressures less than one-half of those in the arm occur with multiple levels of disease (Figure 2 ) ; (iv) rest pain, tissue necrosis, or both, are commonly observed with pressures helow 40 mm H g ; (v) if the ankle pressure
CHRONIC ARTERIAL OCCLUSION Peripheral.-The diagnosis may be made and the extent assessed of lesions involving the limb arteries by measuring the ankle systolic pressure and determining segmental limb gradients by the four cuff technique. The measurements at the ankle can also be made
Reprints: D. E. Strandness, jr, M.D., Professor of Surgery, Department of Surgery, University of Washington, Seattle, Washington 98195.
AUST.N.Z. J. SURG., VOL.47-N0.
I,
FEBRUARY, 1977
the velocity patterns in all the major arteries and veins of the upper and lower extremities. (C:ourtesy o f Medsonics, 340 Pioneer Way, P.0. Box RI, Mountain View. California 94042.) 115
DOPPLER ULTRASOUND
falls after mild exercise, this is abnormal; and (vi) direct arterial surgery will improve distal pressure and flow to the extent to which the disease has been corrected. These measurements can be used to follow the progress of collateral artery development and evaluate the success of the arterial reconstruction (Figure 3). Extracranial.-Atherosclerosis of the carotid bifurcation produce symptoms of transient cerebral ischmnia or completed stroke by
STRANDNESS
the test is positive in at least 95% of cases. If the test is negative, it most definitely does not rule out the presence of a small plaque which may be the source of emboli. ACUTEVENOUSTHROMBOSIS AND THE POSTPHLEBITIC SYNDROME Whereas the symptoms and signs of peripheral arterial occlusion are often specific and helpful clinically, this is usually not the case with deep vein thrombosis. ~h~ problem is that even when symptoms and signs are present, they are not specific, and the condition may be confused with a variety of other diseases. While contrast venography remains the diagnostic gold standard, the Doppler may be used to assess the major deep veins from the level of the posterior tibia1 vein at the ankle to the external iliac vein in the groin. Venous thrombosis is detected by one of two findings: (i) absence of a venous flow signal where it is normally heard, even with compression of the limb distal to the transducer.
FIGURE 2 : Relationship between the ankle systolic pressure (expressed as Yo of the brachial) and the extent of arterial occlusion proven by arteriography. (From Carter, S.A. (19691, .7. Amer. med. Ass., 207: 1869.)
either the release of emboli or a reduction in hemispheric blood flow by a high-grade stenosis or occlusion. By using a directional Doppler, it is possible to detect hanodynamically significant stenoses or occlusions of the internal carotid artery by noting the direction of flow in the supraorbital artery and evaluating the effects of temporal artery compression. Normally, flow is outward from the skull via the ophthalmic artery, with temporal artery compression resulting in augmentation of that flow. When the internal carotid artery is narrowed by more than half of its diameter, the flow is reversed in the ophthalmic artery, with temporal artery compression resulting in a marked reduction or cessation of flow in the supraorbital artery. If the internal carotid artery is occluded or has a greater than 50% narrowing of its diameter, I 16
FIGURE3 : The changes in the ankle blood pressure response that occurred after common femoral endarterectomy were secondary to disease progression. The problem was detected by both a reduction in resting ankle pressure and its response to exercise.
This is normally called augmentation of flow ; and (ii) the presence of a continuous venous flow signal which is unaffected by a deep inspiration or a Valsalva manceuvre. The continuous flow signal means that venous blood is being diverted around areas of occlusion via collateral vessels which are not influenced to AUST. N.Z. J. SURG.,VOL.47-No.
I,
FEBRUARY, 1977
DO P PLER ULTRAS OUND
ST R A N D N E SS
the same degree by the pressure changes that occur in the abdomen and are associated with respiration. The accuracy of this test has varied a great deal, depending upon the experience of the investigator. If the test is completely performed and identical sites on each limb are compared, the false-positive and false-negative incidence should not exceed 10%. This compares favourably with the results of plethysmography i n this field. If the valves of the superficial, deep, or perforating veins are incompetent, this is easily assessed with the velocity detector. Normally, any nianceuvre which increases proximal venous pressure, such as a Valsalva manceuvre or proximal limb compression, will not result in retrograde flow through the valves. Any reversal of blood flow by any of these pressure changes signifies valvular incompetence-the hallmark of venous damage. Since the super-
FIGURE 4 : Ultrasonic arteriogram demonstrating two
stenoses of the internal carotid artery as verified by contrast arteriography.
ficial, deep, and perforating veins can be selectively examined, it is possible to distinguish primary varicose veins from those occurring secondary to disease of the deep venous system. THEFUTURE While the application of continuous wave, direction-sensing devices to clinical problems will continue to be explored and expanded, the AUST. N.Z. J. SURC.,VOL. 47-No.
I, FEBRUARY, 1977
coming era will be concerned with pulsed ultrasonic systems that can be used for arterial imaging and measurement of flow from discrete points along the sound beam (Figure 4). These methods will soon be available for more widespread use and application.
RECOMMENDED REFERENCES STRANUNESS, D. E., JR, SCHULTZ,R. D., SUMNER, D. S. and RUSHMER,R. F. (1967), Ultrasonic flow detection: A useful technique in the evaluation of peripheral vascular disease, Anzer. J . Surg., 113: 311. An account of the technique and the different clinical situations in which it may be used. NIPPA,J. H., HOKANSON, D. E., LEE, D. R., SUMNER, D. E., JR (I975), PhaseD. S. and STRANDNESS, rotation for separating forward and reverse blood velocity signals, IEEE Trans. on Sonics and Ultrason., SU-22/5 : 340. A description of the latest advances in the development of a direction-sensing Doppler system for use in peripheral arteries and veins. BARNES, R. W., BONE, G. E., REINERTSON,J., HOKANSON,D. E., SLAYMAKER, E. E. and STRANDNESS, D. E., JR (1976), Noninvasive carotid angiography. Prospective validation by contrast arteriagraphy, Surgery, 80: 328. The latest results with ultrasonic imaging a s compared with contrast arteriography are reviewed. CARTER,S. A. (1969), Clinical measurement of systolic pressures in limbs with arterial occlusive disease, J . Amer. med. Ass., 207: 1869. This excellent article reviews the relationship between chronic arterial occlusion and its effects on ankle systolic pressure. YAO, S. T. (1970), Experience with the Doppler ultrasound flow velocity meter in peripheral vascular disease, in Gillespie, J. A. (Ed.), Modern Trends in Vascular Surgery, I, Appleton-Century-Crofts, New York. This report reviews the experience a t St Mary’s Hospital in London, England, with the Doppler instrument. CARTER,S. A. (I972), Response of ankle systolic pressure to leg exercise in mild or questionable arterial disease, N . Engl. J . M e d . , 287: 578. This article demonstrates how . measuring limb blood pressures after exercise can detect stenoses which are insignificant when the subject is at rest. BONE,G. E. and BARNES,R. W. (1976), Limitations of the Doppler cerebrovascular examination in hemispheric cerebral ischzmia, Surgery, 79 : 577. LYE, C. R., SUMNER,D. S. and STRANDNESS, D. E., JR (1976), T h e accuracy of the supraorbital Doppler examination in the diagnosis of hemodynamically significant carotid occlusive disease, Surgery, 79: 42. T h e above two articles review the results of Doppler examination in the detection of significant internal carotid artery disease.
117
STRANDNESS
D O P P L E R ULTRASOUND
D. E., J R and SUMNER,D. S. (1975), STRANDNESS, Ultrasonic Techniques in .Angiology, Hans Huber Publ. Co., Berne, Switzerland. This monograph reviews the use of the ultrasonic velocity detector in the evaluation of peripheraI arterial and venous disorders as well as the extracranial arterial system. STRANDNESS, D. E., JR (1975)~ Ultrasound and plethysmography in the diagnosis of acute
venous thrombosis in prophylactic therapy of deep vein thrombosis and pulmonary embolism, D H E W Publ. NO. ( N I H ) 76-866. This publication, obtainable from the National Institutes of Health in Washington, D.C., reviews the entire field of acute venous thrombosis from the standpoints of ztiology, detection, treatment, and prophylaxis.
English, which can express the thoughts of Hamlet, or the tragedy of Lear, has no words for the shiver and the headache. It has all grown one way. The merest schoolgirl, when she falls in love, has Shakespeare or Keats to speak her mind for her; but let the sufferer try to describe a pain in his head to a doctor and the language runs dry. There is nothing ready for him. H e is forced to coin words himself, and, taking his pain in one hand, and a lump of pure sound in the other . . . crush them together that a brand new world in the end drops out. Virginia Woolf, On Being Ill, 1947.
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AUST. N.Z. J. SURG.,VOL. 47-No.
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FEBRUARY, 1977
