Relationships of infant birth size to maternal lipoproteins, apoproteins, fuels, hormones, clinical chemistries, and body weight at 36 weeks gestation.

It has been hypothesized that plasma triglyceride fatty acids may traverse the placenta and contribute to infant adiposity particularly in GDM pregnancy. It has also been hypothesized that high-density lipoproteins (HDL) can both deliver cholesterol to and remove cholesterol from the placenta. To determine if these maternal parameters are related to fetal growth in normal pregnancy, we have examined relationships of lipoprotein lipids, apoproteins, hormones, fuels, clinical chemistries, and maternal weight at 36 wk gestation to infant birth weight, birth weight ratio (birth weight corrected for gestational age), birth length, and head circumference in a cohort of pregnant women attending a prepaid health plan, Group Health Cooperative of Puget Sound. Associations were examined using a multivariate regression analysis of several groups of related variables. Results show that the birth weight and/or birth weight ratio are weakly positively associated with maternal very-low-density lipoprotein (VLDL) triglyceride and statistically significantly positively associated with apoprotein A-I, placental lactogen, estradiol, bilirubin, and maternal prepregnancy weight and pregnancy weight gain. Glucose and insulin predict birth weight only in pairwise analysis. Significant negative predictors of birth weight or birth weight ratio include VLDL cholesterol, apoprotein A-II, SGOT, and creatinine. Significant positive predictors of birth length include apoproteins A-I, placental lactogen, and maternal weight. Apoprotein A-II negatively predicts birth length. Only maternal prepregnancy weight predicts head circumference.(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid and lower extremity arterial disease in patients with renal artery atherosclerosis.

BACKGROUND: Atherosclerotic lesions of the carotid and lower extremity arteries may be associated with renal artery stenosis and influence the management of patients with renal artery disease. OBJECTIVE: To document the prevalence and clinical features of carotid and lower extremity arterial disease in patients with renal artery atherosclerosis. METHODS: An analysis of baseline data on 149 patients enrolled in a prospective natural history study of atherosclerotic renal artery stenosis. Patients with at least 1 abnormal renal artery by duplex scanning were eligible. Carotid artery disease was evaluated by duplex scanning, and ankle/brachial indices were used to assess the lower extremity arteries. Disease at each of the 3 arterial sites was classified as mild, moderate, or severe based on the extent of involvement on both sides. Serum urea nitrogen, creatinine, and lipid levels were also measured. RESULTS: Severe renal, carotid, or lower extremity arterial disease was present in 44%, 19%, and 21% of the patients, respectively. There was a trend for patients with increasing degrees of renal artery disease to have increasing degrees of carotid and lower extremity arterial disease. The prevalence of severe carotid artery disease increased from 7% in the mild renal artery group to 28% in the severe renal artery group. Clinical factors that were most predictive of severe disease were elevated apolipoprotein B levels for the renal arteries, high serum urea nitrogen or creatinine levels for the carotid arteries, and smoking for the lower extremity arteries. CONCLUSIONS: There was a strong association between severe renal artery atherosclerosis and severe carotid artery disease. Patients with renal artery disease also had a high prevalence of lower extremity arterial disease. In this patient population, screening for lower extremity arterial disease can be reserved for those with signs or symptoms of peripheral ischemia. Noninvasive carotid screening is justified in patients with renal artery disease to detect asymptomatic lesions that require either immediate surgical treatment or serial follow-up for disease progression.

Progression of lower-extremity arterial occlusive disease in type II diabetes mellitus.

The prevalence of lower-extremity arterial occlusive disease (LEAOD), the progression of LEAOD, and the incidence of new LEAOD were determined by noninvasive method in 410 volunteers between the ages of 50 and 70 yr; 252 individuals had type II (non-insulin-dependent) diabetes, 158 were control subjects. LEAOD was monitored with the ankle/arm systolic blood pressure index in combination with Doppler arterial velocity waveform analysis. LEAOD was much more prevalent in the type II patients (22%, 55 of 252) than in the control subjects (3%, 4 of 158) (P less than .00001). The prevalence of risk factors for LEAOD was much higher in the type II patients, including elevated triglyceride, depressed high-density lipoprotein (HDL) cholesterol, hypertension, smoking, and elevated systolic blood pressure. In type II diabetic patients the incidence of new LEAOD over a 2-yr period (14%, 28 of 197) was lower than the incidence of LEAOD progression (87%, 45 of 52). Type II patients with LEAOD also had a high incidence of mortality (22%, 12 of 55) compared with those without LEAOD (4%, 8 of 197) (P less than .0005). A risk score including smoking history, duration of diabetes, depressed HDL cholesterol, total cholesterol, elevated systolic blood pressure, and low obesity index is related to LEAOD. After accounting for the effect of all of the risk factors, we suggest that type II diabetes contributes additional risk for LEAOD.

Renal atrophy and arterial stenosis. A prospective study with duplex ultrasound.

Renal artery disease is an important cause of both renal failure and hypertension. Duplex ultrasound is a reliable noninvasive method for classifying the severity of renal artery lesions and can be repeated to follow the course of the disease over time. The purpose of this study was to determine the changes in kidney size associated with various degrees of renal artery disease. Serial kidney lengths were measured as part of a prospective duplex ultrasound study of patients with renal artery narrowing. Fifty-four patients (22 men, 32 women; mean age, 65.8 years) with 101 renal artery and kidney sides eligible for follow-up were evaluated at 6-month intervals for an average of 14.4 months (range, 4 to 24 months). No kidneys with renal arteries classified as normal or less than 60% diameter stenosis by duplex criteria were found to have a decrease in length of greater than 1 cm during follow-up. In kidneys with a high-grade renal artery stenosis (> or = 60% diameter reduction), 26% (13 of 49 sides) were found to have a decrease in length of greater than 1 cm. The average decrease in length was 1.9 cm (range, 1.2 to 3.4 cm). By life table analysis, the estimated risk of a decrease in length of greater than 1 cm for kidneys with 60% stenosis or greater was 19% at 1 year. Loss of renal mass, as documented by ultrasound measurement of kidney length, is an important consequence of high-grade renal artery stenosis.

Population-based reference values for lecithin-cholesterol acyltransferase (LCAT).

Plasma unesterified cholesterol is converted to cholesteryl ester by the enzyme lecithin-cholesterol acyltransferase (LCAT). Plasma levels of LCAT were measured by a sensitive double antibody radioimmunoassay in a sample from an adult employee population, ages 20-59 years, in the Pacific Northwest. After adjusting for differences in relative body mass, women had significantly higher LCAT levels (5.90 +/- 1.06, n = 154) than men (5.49 +/- 0.89, n = 83). For ages 20-59 years, LCAT levels showed a slight association with age: r = 0.13 for men and 0.29 for women. LCAT was positively correlated with relative body mass, total cholesterol, and LDL cholesterol. Men who smoked cigarettes had significantly lower LCAT mass than men who did not smoke cigarettes. No statistical differences in mean LCAT values were found between drinkers and nondrinkers. The 5th percentile LCAT value was 4.3 micrograms/ml for both men and women not using hormones. The 95th percentile value was 7.3 micrograms/ml for men and 7.8 micrograms/ml for women regardless of hormone use. Subjects phenotypically LCAT-deficient by clinical criteria and by the absence or near absence of LCAT activity had levels of LCAT mass well below the reference values: 0.73 +/- 0.70, range 0.10 micrograms/ml to 2.65 micrograms/ml, n = 20. Parents or children of LCAT-deficient subjects, i.e., obligate heterozygotes for familial LCAT deficiency, had reduced levels: 3.59 +/- 0.69, range 2.59-4.61 micrograms/ml, n = 19.

Distribution of lipoproteins triglyceride and lipoprotein cholesterol in an adult population by age, sex, and hormone use- The Pacific Northwest Bell Telephone Company health survey.

This report describes the distribution of lipoprotein triglyceride and lipoprotein cholesterol in employees of the Pacific Northwest Bell Telephone Company. Means, medians, and selected percentiles are presented for very low, low, and high density lipoproteins (VLDL, LDL, and HDL, respectively) in 606 randomly selected white subjects aged 20-59. Results are specific for age decade, sex, and female sex hormone usage. Women who use sex hormones have significantly higher concentrations of triglycerides in all of the fractions across all age decades from 20 to 59 than do women not taking hormones. The average VLDL, LDL, and HDL triglyceride levels in women taking hormones are 69, 25 and 18 mg/dl which are considerably higher than the corresponding averages of 44, 17 and 12 mg/dl noted in women not taking hormones. Men have the highest average VLDL triglyceride value (85 mg/dl) but their average triglyceride concentrations in the LDL and HDL fractions (18 and 12 mg/dl) approximate those of women not taking hormones. This study in a well-defined population provides references standards for lipoprotein triglyceride concentrations. These results can be used to evaluate the effect of sex hormone treatment on the lipoprotein triglyceride content in VLDL, LDL and HDL, and to assess triglyceride content as a potential risk factor in men and older women.

PIP: A study of lipoprotein triglyceride and lipoprotein cholesterol distribution was done between 1973-76 on a randomly selected group of 606 white male and female employees, aged 20-59, of the Pacific Northwest Bell Telephone Company. Data obtained were used to ascertain whether triglyceride content of lipoprotein differs in men and women by observing mean, standard and percentile distribution of VLDL, LDL, and HDL (very low, low, and high density lipoprotein). A high proportion of women, i.e. 50% in the age group 20-29, and 50-59, reported current use of some form of exogenous sex hormone preparation. The average VLDL, LDL, and HDL triglyceride level in women taking hormones were 69, 25, and 18 mg/dl, considerably higher than the corresponding averages of 44, 17, and 12 mg/dl observed in women not taking hormones. For VLDL triglyceride, the youngest and oldest male groups had lower average levels than females in the same age taking hormones; in the middle-age group the levels were the same among men and women. For VLDL cholesterol, the 20-29 year old male and female hormone users had similar concentration levels, but male values were higher in each of the remaining age strata. These data confirm the fact that lipoprotein triglyceride rise is associated with the type of oral contraceptives used in the U.S., and with postmenopausal treatment as well.

Relationships of gender, sex hormone use, and age with lipoprotein cholesterol/triglyceride ratios in an adult population. The Pacific Northwest Bell Telephone Company health survey.

UNLABELLED: Effects of gender, sex hormone use, and age on lipoproteins composition have been evaluated in 603 Caucasian subjects, ages 20-59, randomly selected from employees participating in the Pacific Northwest Bell Telephone Company Health Survey. Lipoprotein composition in this analysis is defined as the cholesterol to triglyceride (C/TG) ratio in each lipoprotein fraction. The lipoprotein C/TG ratio is inversely related to the lipoprotein triglyceride concentrations in VLDL, LDL and HDL; the ratio falling in each instance as lipoprotein triglyceride concentration increases. Plots of this relationship are virtually superimposable among women hormone users and nonusers and men in VLDL and HDL and between men and nonhormone taking women in LDL. A consistently lower C/TG ratio is observed in LDL for hormone-treated women compared to the other 2 groups. Age in these analysis is without effect. CONCLUSIONS: We hypothesize that a lower LDL (C/TG) ratio is hormone-treated women may render the lipoprotein less crystalline or smectic and potentially less atherogenic. No such difference exists in the lipoprotein C/TG ratio between men and nonhormone-treated women and therefore cannot explain the observed difference in atherosclerosis sick. Nonetheless, the C/TG ratios may predict atherosclerosis if the ratio is high in VLDL or in LDL. However, the significance of the HLD (C/TG) ratio remains to be established.

Venous diameter and compliance after deep venous thrombosis.

Duplex sonography was used to measure diameters of the common femoral, superficial femoral, and popliteal veins in 56 patients followed for more than 6 months after DVT and in 17 normal subjects. Diameter changes with Valsalva's maneuver were also measured as an index of venous compliance. Among patients with unilateral thrombosis, segments with residual disease were 0.07 to 0.28 cm smaller than the contralateral disease-free side (p < 0.05 for CFV and SFV) with a diameter index (ipsilateral/contralateral diameter) significantly less than that of normal subjects. In contrast, completely recanalized segments were not significantly different from the contralateral side and had diameter indices indistinguishable from normal subjects. Distensibility with Valsalva's maneuver was not significantly different from normal in DVT patients with either resolved or residual disease. Venous diameter does decrease following DVT, but returns to normal following complete recanalization and is not associated with chronic venous compliance changes.

The relationship of venous diameter to reflux, cephalad thrombus and cephalad reflux following deep venous thrombosis.

Duplex ultrasonography was used to measure the diameters of the common femoral, superficial femoral and popliteal vein segments in 123 patients following DVT. A cross sectional analysis was done based on the most recent visit to determine chronic venous diameter changes following DVT. Venous diameters in recanalized segments were smaller at all levels compared to those never occluded (p = 0.06 for CFV and p < 0.05 for SFV and PV). After accounting for a previous history of occlusion, the diameters of the segments with and without reflux were not significantly different. There was also no evidence of venodilation in segments caudal to cephalad reflux or thrombus. Recanalized veins are smaller in diameter than those which were never thrombosed. Cephalad thrombus or reflux is not associated with venodilatation of caudal segments. Reflux following DVT is probably secondary to valvular damage rather than hypertension, since there was no diameter difference between refluxing and non-refluxing segments.

Blood pressure, antihypertensive medication, and atherosclerotic renal artery stenosis.

The relationship between atherosclerotic renal artery stenosis (ARAS) and blood pressure control remains poorly understood. Duplex ultrasonography is a noninvasive method for detecting and grading ARAS. The purpose of this study was to characterize the relationship between the degree of ARAS, levels of blood pressure, and control of blood pressure with antihypertensive medication. A cross-sectional analysis was performed on 139 patients with ARAS. All patients had at least one diseased renal artery by duplex ultrasound. Renal arteries were classified as normal, less than 60% stenosis, or 60% or greater (high-grade) stenosis. Data regarding blood pressure, coexisting risk factors, and medications were collected. The extent of ARAS was significantly associated with progressive elevation of the systolic blood pressure, whereas the diastolic component was elevated in the case of unilateral high-grade stenosis: no high-grade stenoses, 153 +/- 22/81 +/- 10 mm Hg; unilateral high-grade stenosis, 162 +/- 22/86 +/- 9 mm Hg; and bilateral high-grade stenoses, 174 +/- 27/82 +/- 9 mm Hg (P = 0.002 systolic; P = 0.02 diastolic). Eighty-two percent of the patients were taking known antihypertensive medications. Angiotensin-converting enzyme inhibitor (ACEI) usage versus nonusage was associated with a significantly lower systolic (157 +/- 27 v 169 +/- 22 mm Hg; P = 0.03) and diastolic (79 +/- 9 v 85 +/- 9 mm Hg; P = 0.001) blood pressure. The effect of ACEI usage was observed in patients with high-grade ARAS. None of the other classes of antihypertensive medications were associated with significantly lower blood pressure. In patients with ARAS, blood pressure levels were correlated with the severity of renal artery disease. Patients taking ACEIs had significantly lower blood pressures, and the effect of ACEI usage was strongest among patients with unilateral ARAS.

Prevalence of carotid and lower extremity arterial disease in patients with renal artery stenosis.

Atherosclerosis is the most common cause of renovascular hypertension secondary to hemodynamically significant stenoses (> 60% diameter reduction). To assess the prevalence of atherosclerosis in the peripheral arteries and carotid bifurcation, we prospectively studied 60 patients who had renal artery stenosis documented by ultrasonic duplex scanning. Disease of the peripheral arterial circulation was assessed by the measurement of the ankle/brachial systolic pressure ratio. To evaluate the extracranial carotid artery, ultrasonic duplex scanning was employed. The prevalence of a 50-100% diameter reducing stenosis in the carotid artery was 46% in patients with a > 60% diameter reducing renal artery stenosis. The prevalence of severe peripheral arterial disease was 73% in those patients with a high grade renal artery lesion. The prevalence of severe disease in the peripheral and carotid arteries was less (50% and 25%, respectively) in patients with renal artery lesions that reduced the diameter of the renal artery less than 60%. The high prevalence of associated lesions in the carotid and peripheral circulation in patients with renovascular disease secondary to atherosclerosis should prompt investigation of these major arteries when renal artery disease is detected. Disease of the carotid and peripheral arteries is a common cause of morbidity and should be treated according to accepted guidelines.

A prospective study of disease progression in patients with atherosclerotic renal artery stenosis.

The natural history of renal artery stenosis (RAS) has been difficult to document because serial arteriography is rarely justified. Duplex scanning is a noninvasive technique that is ideally suited for both screening and follow-up of RAS. In this approach, renal arteries are classified as normal, < 60% stenosis, > or = 60% stenosis, or occluded, and disease progression is defined as a change in the duplex classification. The purpose of this study was to determine the rate of disease progression in atherosclerotic RAS by serial duplex scanning. At least one abnormal renal artery was identified in each of 76 patients being screened for RAS. Of the 152 renal arteries, 20 were excluded (14 prior interventions, 5 occlusions, 1 technically inadequate duplex scan), leaving 132 for the natural history follow-up protocol. The patient group included 36 men and 40 women, with a mean age of 67 years, who were followed for a mean of 32 months (maximum 55 months). The initial status of the 132 renal arteries was normal in 36, < 60% stenosis in 35, and > or = 60% stenosis in 61. The cumulative incidence of progression from normal to > or = 60% RAS was 0% at 1 year, 0% at 2 years, and 8% at 3 years. The cumulative incidence of progression from < 60% to > or = 60% RAS was 30% at 1 year, 44% at 2 years, and 48% at 3 years. All 4 renal arteries that progressed to occlusion had > or = 60% stenoses at the initial visit, and for those arteries with a > or = 60% stenosis, the cumulative incidence of progression to occlusion was 4% at 1 year, 4% at 2 years, and 7% at 3 years. Progression of RAS occurred at an average rate of 7% per year for all categories of baseline disease combined. Progression of atherosclerotic RAS is relatively common, particularly from < 60% to > or = 60% stenosis.

Effects of pregnancy, postpartum lactation, and oral contraceptive use on the lipoprotein cholesterol/triglyceride ratio.

Lipoprotein cholesterol/triglyceride ratio changes have been observed previously with sex hormone use. To determine if the lipoprotein cholesterol/triglyceride ratio is similarly changed by pregnancy and postpartum lactation, we examined pregnant subjects at 36 weeks gestation and the same women at 6 weeks postpartum and compared them to age-matched, nonpregnant women using or not using oral contraceptives. The cholesterol/triglyceride ratios were examined as means and medians and as curvilinear functions of increasing triglyceride concentration. Median ratios did not predict all ratio changes identified graphically. At very-low-density lipoprotein (VLDL) triglyceride concentrations below 40 mg/dL, the VLDL ratio is less than control in oral contraceptive users and further reduced in pregnant women. Above triglyceride concentrations of 40-60 mg/dL, the curves in the three groups are indistinguishable. No effect of lactation is observed. The low-density lipoprotein (LDL) cholesterol/triglyceride ratio is comparably lower in pregnant subjects and oral contraceptive users at all concentrations of lipoprotein triglyceride and again there is no effect of lactation. In high-density lipoprotein (HDL), there is no effect of either pregnancy or oral contraceptive use on the cholesterol/triglyceride ratio, while it is significantly higher with lactation. Postpartum decreases in the VLDL and LDL cholesterol/triglyceride ratio are seen at all lipoprotein concentrations independent of lactation. We conclude that triglyceride enriches VLDL at low concentrations and LDL at all concentrations in pregnancy and with oral contraceptive use, suggesting a common, hormonal mechanism. HDL is enriched with cholesterol during postpartum lactation, consistent with decreased transfer of cholesterol to other lipoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical chemistry alterations in pregnancy and oral contraceptive use.

In this study the effects of pregnancy and oral contraceptive use on plasma glucose concentrations, hepatic, renal, and thyroid function tests, and their relationships to plasma lipoprotein lipids after an overnight fast are compared. Observations were made in 546 pregnant women at 36 weeks' gestation, 56 women using oral contraceptive hormones, and 77 women not using sex hormones. All subjects were randomly selected from defined populations. Compared with nonpregnant women not using hormones, median plasma glucose concentrations are 3% lower with oral contraceptive use and 17% lower in pregnancy. Plasma total bilirubin concentrations are lowered by similar amounts in oral contraceptive users (29%) and in pregnancy (32%). Serum glutamic oxaloacetic transaminase is slightly lower among hormone users (9%) but is significantly higher (27%) in pregnancy. Alkaline phosphatase is significantly lower in oral contraceptive users (23%) but is higher in pregnancy (86%). Serum globulin concentrations are unaffected by pregnancy or oral contraceptive use. Compared with nonusers, thyroxine is 30% higher in oral contraceptive users and 100% higher during pregnancy. Serum creatinine is unaffected by sex steroid use but is 28% lower in pregnancy. Associations of these test results with plasma hormone concentrations corroborate hormonal mechanisms and suggest that some alkaline phosphatase and serum glutamic oxaloacetic transaminase come from the placenta. Relationships of these clinical measurements to lipoprotein lipids in pregnancy are generally weak and do not point to important controlling relationships, but effects similar to those seen in nonpregnant subjects are seen with hyperglycemia (associated with elevated triglyceride) and elevated thyroxine levels (associated with lower cholesterol and triglyceride).(ABSTRACT TRUNCATED AT 250 WORDS)

Pattern and distribution of thrombi in acute venous thrombosis.

The location and extent of thrombosis in the deep venous system will determine immediate and long-term outcome. During the past 3 years, we have studied by duplex scanning 833 patients with suspected deep vein thrombosis. In this group, 209 patients (25%) had a positive study. The findings relative to location and extent of involvement are as follows. (1) The right leg was involved in 35% of patients, the left leg in 48%. Bilateral involvement was noted in 17%. (2) The veins most frequently affected by deep vein thrombosis were as follows: superficial femoral in 74%, popliteal in 73%, common femoral in 58%, posterior tibial in 40%, deep femoral in 29%, greater saphenous in 19%, and the inferior vena cava in 2%; multisegment involvement was common. (3) Total occlusion was present in 82% of the patients with deep vein thrombosis, and partial occlusion in 18%. (4) Isolated occlusion of single veins was uncommon. (5) The proximal (above-knee) area was involved in 95% of the cases with deep vein thrombosis, and the calf in 40% of the cases. Isolated calf deep vein thrombosis was found in 6% of the cases with right leg involvement and in 3% for the left. (6) Total leg involvement (iliocaval, femoropopliteal, and calf) occurred in 10% of the patients. Our data confirm the fallibility of the clinical diagnosis of deep vein thrombosis. The frequent involvement of both limbs stresses the importance of not examining just the symptomatic limb. Proximal venous thrombosis (popliteal to inferior vena cava) is much more common than isolated calf vein thrombosis as a cause for symptoms and the referral for study.

A comparison of the cuff deflation method with Valsalva's maneuver and limb compression in detecting venous valvular reflux.

OBJECTIVE: This study was designed to test the results of Valsalva's maneuver and limb compression against the standing-cuff inflation-deflation method for the detection of venous valvular reflux. DESIGN: The study was conducted in 67 patients (134 extremities) who had an episode of deep vein thrombosis. An ultrasonic duplex scanner was used to evaluate two methods of testing for reflux. The most commonly used methods are Valsalva's maneuver and limb compression, both of which can raise the venous pressure and promote reflux. With the cuff method, the patient is studied in the standing position. The cuffs are segmentally placed (thigh to foot) with reflux encouraged when the inflated cuff is suddenly deflated. SETTING: The patients were a part of a long-term natural history study of acute deep vein thrombosis and its effects on venous valve function. OUTCOME MEASURES: Valvular reflux was documented by the appearance of retrograde flow in the vein when the normal transvalvular pressure gradient was reversed. RESULTS: Both limb compression and Valsalva's maneuver can elicit reflux, but the maneuvers are difficult to standardize and come up with meaningful results. With the cuff inflation-deflation method, the time to valve closure was less than 0.5 seconds in 95% of normal subjects. The results were easier to quantify and worked well for all segments of the venous systems--superficial and deep. CONCLUSIONS: The cuff inflation-deflation method provides more uniform quantifiable results for detecting reflux in the superficial and deep veins of the leg.

Flow separation in the carotid bulb: prognostic significance.

It has been previously shown that boundary layer or flow separation occurring in the carotid bulb and detected by duplex scanning denotes minimal or no carotid atherosclerotic disease as demonstrated by angiography and reliably predicts aetiology other than carotid artery disease in symptomatic patients. To evaluate outcome at long-term follow-up we prospectively studied 94 patients (48 males, 46 females) who demonstrated bilateral flow separation. Mean age was 61.2 years (27 to 86 years). Mean follow-up was 57 months (5 to 113 months). There was one death during follow-up at 69 months. It was stroke related. Using age and sex specific death rates for the general population 14.3 deaths would be expected for the same average period. By life table analysis, survival was 98.7% at five years compared to a general population expected 5 year survival of 85.9%. There were no strokes at 5 years of follow-up. (Age and sex specific stroke-free survival for Rochester, MN 1970-1974 is 98% at 5 years). TIA-free survival was 99% at one year (n = 87) and 96% at five years (n = 46). It is concluded that the presence of boundary layer separation in the carotid bulb not only indicates absent or minimal atherosclerotic disease, but is predictive of a favourable long-term outcome with respect to mortality and neurological events.

Serial measurement of cross-sectional area in peripheral vein grafts using three-dimensional ultrasound.

Frequent surveillance of bypass grafts placed in the lower limbs can provide early detection of stenoses. A three-dimensional (3-D) ultrasound (US) imaging system has been used to produce serial surface reconstructions of regions of interest in vein grafts in the lower extremities. Using anatomical reference points, data sets from serial studies are registered in a common 3-D coordinate system. Cross-sectional area measurements are extracted from the surface reconstructions in planes normal to the vessel center axis. These measurements are compared at matched sites over time to track changes in the vessel configuration. The quantitative measurements are paired with surface displays of the vessels for a complete depiction of the changing geometry. Example studies from three patients are shown, for time periods up to 38 weeks. The cross-sectional area measurements highlight regions of remodeling and developing stenoses within the grafts.

Vein graft surveillance with scanhead tracking duplex ultrasound imaging: a preliminary report.

A severe arterial occlusion in the leg usually is bypassed by implanting a saphenous vein harvested from the limb. Once implanted, the vein functions well but over time may develop stenoses that may lead to occlusion. In order to detect and correct the stenoses that may lead to graft failure, frequent surveillance of the vein graft is required. A new ultrasound imaging method was developed to display the panoramic view of the vein graft in combination with its blood flow velocity waveform for surveillance. The panoramic view is the projection (ray-casting) image of multiple B-mode images with sequential longitudinal view of the vein graft. The velocity waveform also is recorded along the vessel with pulsed Doppler ultrasound. The acquired images and waveforms from the ultrasound scanner are registered individually in three-dimensional space with an electromagnet-based position and orientation sensor located on the scanhead. A prominent point on the scar from the surgery is used as the fiducial mark for spatial registration, so that the same lesion in the vein graft can be tracked automatically at each visit for retrospective study.

Management of internal carotid artery occlusion.

Although attempts to restore patency of occluded internal carotid arteries are now rarely made, endarterectomy in the contralateral artery, external carotid endarterectomy and until recently EC/IC bypass have remained surgical options in the management of such patients. Over a four-year period at this institution 104 patients underwent carotid endarterectomy for stenosis. In this group the contralateral carotid was patent (Group A). Fifty-four patients with unilateral carotid artery occlusion underwent contralateral endarterectomy (Group B), 8 underwent ECA/ICA bypass (Group C) and 4 an ECA endarterectomy (Group D). No statistically significant difference was noted in perioperative stroke and death rates for Groups A and B were (1% and 1%) and (3.7% and 1.9%) respectively. One Group C patient died from perioperative stroke (12.5%). For late events the life table adjusted annual rates for stroke and mortality were similar, Group A (stroke 2.1% and death 5%), and Group B (stroke 1.6% and death 5%). In Group C stroke rate was 10% and death 3%. All four patients undergoing ECA endarterectomy were relieved of their symptoms. It is concluded that in patients with internal carotid artery occlusion TEA may be performed with perioperative morbidity and mortality rates comparable to those when the opposite carotid artery is patent. The late outcome for stroke compares favorably with the reported natural history of the disease and outcome for such patients treated medically in the Joint Study of Extracranial Occlusion and EC-IC Bypass Study. External carotid artery endarterectomy appears useful in the treatment of embolic events on the occluded side. ECA/ICA bypass does not appear to confer benefit.