[Fibrinolytic agents in peripheral vascular diseases].
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Chymotrypsin↗
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A critique of laboratory methods in peripheral vascular disease.
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Humans↗
[Vascular penile study with Doppler ultrasonography in subjects without vascular disease].
The Eco-Doppler technique allows a fast, non-invasive and effective study of pental vascularization. Ninety-three subjects, aged 20-66, with no vascular disease were studied: 20 healthy volunteers and 73 with psychogenic dysfunctions. All subjects underwent a baseline study, and 89 a second study after intracavitary injection (ICI) (10 papaverine and 79 PgE1). No differences were seen between both drugs. Flowmetry parameters were analyzed at rest and post-ICI. At baseline, patients with psychogenic dysfunctions showed less diastolic speed (p < 0.05), acceleration (p < 0.001) and resistance index (p < 0.05) than normal subjects. After administration of the drug, no differences were detected between both groups that formed an homogeneous sample. Subjects with no vascular disease presented arterial dilatation after ICI, the vessels appearing with thin and parallel walls, homogeneous lumen and following a straight course. Flow speed parameters experienced significant changes: systolic speed increase by 153 +/- 97% (p < 0.001) and reached 34.7 +/- 9.3 cm/s; increase of diastolic speed was lower; but flow time and acceleration also increases although not significantly due to their high variability. At 20 minutes after ICI the resistance index is 0.83 +/- 0.1, higher (p < 0.001) than that observed at rest, expressing the high intracavitary pressure that exists when full erection is achieved.
Adult↗
From the RSNA refresher courses: MR imaging of aortic and peripheral vascular disease.
Acquired diseases of the aorta and peripheral arteries are common. Owing to technical advances, magnetic resonance (MR) angiography has become the primary imaging modality for assessment of aortic and peripheral arterial disease. Contrast material-enhanced MR angiography is a rapid and robust technique that has emerged as the principal MR angiographic technique for evaluation of vascular disease. Two-dimensional time-of-flight MR angiography still has some well-validated applications, especially in distal peripheral vascular disease. Phase-contrast flow imaging is an important technique for quantification of blood flow. Black-blood imaging is a valuable tool for evaluation of the vessel wall. Understanding the principles of the main MR angiographic techniques is essential for consistent acquisition of diagnostic images. In addition, tailoring the acquisition parameters and the imaging protocol to the vessel being imaged and the clinical question is mandatory for optimal results. Future technical developments that will lead to faster image acquisition and better contrast agents promise to further improve image quality.
Adult↗
Exercise-induced changes in oxygen saturation in the calf muscles of elderly subjects with peripheral vascular disease.
This study noninvasively measured hemoglobin oxygen saturation in young (n = 6, 28 +/- 6 yrs), old healthy (n = 20, 68 +/- 7 yrs), and old subjects with mild peripheral vascular disease (PVD) (n = 8, 72 +/- 4 yrs). Hemoglobin oxygen saturation was measured as the difference in absorption at 760 and 850 nm light using near-infrared spectroscopy (NIRS). The lateral soleus muscle was studied after mild plantar flexion exercise. The time constant of recovery of oxygen saturation (HBO2Tc) was 21.5 +/- 8.6 s in young, 26.9 +/- 13.5 s in old healthy subjects. PVD subjects had HbO2Tc values of 104.4 +/- 41.1 s in their "bad" leg and 57.6 +/- 42.2 s in their "good" leg. The correlation between HbO2Tc and ankle-arm pressures was significant (r2 = .63, p < .001). Six younger normal, five older normal, and seven PVD subjects also performed a progressive walking test. Normal subjects completed the test without difficulty, and older normal subjects showed progressive deoxygenation. PVD subjects complained of calf pain (4 out of 5 were able to finish) and showed near-maximal deoxygenation throughout the test. In summary, NIRS measurements show promise as a method of evaluating the kinetics of oxygen saturation, particularly in patients with mild peripheral vascular disease.
Adult↗
Neuro-ophthalmic aspects of vascular disease.
One of the most susceptible sites to vascular diseases is the optic nerve head. By innovative approaches using morphometry and in situ hybridization, vascular and extracellular characteristics of the human optic nerve head were examined. Nonarteritic ischemic optic neuropathy occurs due to vascular insufficiency within the optic nerve head. Various local and systemic risk factors have been proposed among which smoking and acute hypotension are now included. Anatomically abnormal discs such as the small optic disc, tilted disc, and optic nerve drusen are recognized as "disks at risk" and hyperopia may be an additional predisposing factor. Ocular, neurological, and vascular disorders due to giant cell arteritis were reviewed. Intravenous high-dose methylprednine should be administered in certain cases. Differentiating nonarteritic from arteritic ischemic optic neuropathy is sometimes difficult. Isolated choroidal ischemia or choroidal filling delay may be an indication of giant cell arteritis. Studies have been conducted on the vascular event, amaurosis fugax (transient monocular visual loss), and the results of some of these studies are discussed.
Blindness↗
Prospective evaluation of peripheral vascular disease in heart transplant recipients.
PURPOSE: Retrospective reviews suggest that the progression of peripheral vascular disease (PVD) may be accelerated in heart transplant recipients. This study was undertaken to determine the incidence and to identify those risk factors that may be associated with the development or progression of PVD in these patients. METHODS: Between January 1990 and December 1993 a prospective vascular screening protocol including abdominal ultrasonography, Doppler-derived ankel-brachial pressure indexes (ABI), and carotid artery duplex imaging was added to the routine preoperative and annual postoperative evaluation of 239 heart transplant recipients. RESULTS: Thirty-one significant vascular lesions were detected in 10% (24 of 239) of patients 52 +/- 9 years of age at a mean of 3.2 years after transplant. The distribution of lesions included carotid artery stenosis (11), femoropopliteal occlusive disease (10), aortoiliac occlusive disease (five), aortic aneurysm (four), and renal artery stenosis in one patient. Revascularization procedures were performed in 12 (50%) patients (carotid endarterectomy (four), aortobifemoral bypass grafting (three), abdominal aortic aneurysm repair (two), transluminal angioplasty (two), splenorenal bypass (one), and femorotibial bypass grafting (one)). One patient with diabetes mellitus (DM) was found to have noncompressible vessels during pretransplant evaluation. An additional 26 patients (11%), seven with DM, had noncompressible vessels in the lower extremities during the follow-up period. Logistic regression analysis revealed that the development of posttransplant PVD was associated with smoking (p < 0.05) and ischemic cardiomyopathy as an indication for transplantation (p < 0.05). The development of noncompressible vessels was associated with younger age (p < 0.05) and the presence of diabetes (p < 0.05). CONCLUSION: Posttransplant peripheral vascular disease occurred in 10% of heart transplant recipients and is associated with pretransplant ischemic cardiomyopathy and smoking. A previously unrecognized subgroup of patients who have noncompressible vessels after operation is described. If the long-term survival of the heart transplant recipient is to be improved, routine follow-up to identify and treat those patients at greater risk appears justified.
Adolescent↗
Raynaud phenomenon and the vascular disease in scleroderma.
PURPOSE OF REVIEW: Raynaud phenomenon is the earliest and most common clinical manifestations of scleroderma (systemic sclerosis). Therefore, Raynaud phenomenon offers the best window into the investigation of the early steps in the pathogenesis of systemic sclerosis. This review focuses on the differential diagnosis of Raynaud phenomenon, the transition of Raynaud phenomenon to systemic sclerosis, mechanisms and consequences of vascular injury and dysfunction in systemic sclerosis, and therapeutic options. RECENT FINDINGS: Careful clinical evaluation using a simple definition of Raynaud phenomenon is the most reliable and reproducible method in the diagnosis. Although the assessment of vascular function by noninvasive methods is still not sensitive enough for the evaluation and follow-up of individual patients, it helps in the differential diagnosis and in population studies. Progressive deficiency in vasodilatory capacity of the vessels is proposed as a mechanism of Raynaud phenomenon, particularly in systemic sclerosis. In addition, decreased fibrinolysis and enhanced coagulation pathways undoubtedly contribute to vascular dysfunction. The mechanism of endothelial injury is still elusive, yet endothelial apoptosis mediated by antiendothelial antibodies is the most attractive hypothesis now. Therapies directed at the vascular disease continue to focus on the alleviation of vascular spasm. However, immunosuppressive therapy may influence the levels of vascular injury markers and thus may have an effect on the vascular disease itself. SUMMARY: Continued progress in the investigation of the vascular aspects of scleroderma is described in this review. Immune involvement in the early stages of the disease and mechanism of vascular repair in advance cases are some of the highlights of last year's progress.
Humans↗
Doppler ultrasonography of peripheral vascular disease: the potential for ultrasound contrast agents.
Noninvasive diagnosis of peripheral vascular disease started with the introduction of Doppler technology. The development of high frequency ultrasound and color Doppler imaging allows continuous assessment of vascular disorders along the arterial tree. However, the technique remains operator dependent. It also suffers from anatomic limitations, such as bowel gas and ultrasound attenuation due to depth or wall calcification. Ultrasound contrast agents increase the Doppler signal intensity and should therefore reduce the rate of technical failures. They are useful for detecting the flux in cases of attenuated ultrasound beam and reduced blood flow. Their administration using continuous infusion protocols increases the duration of the effect. New imaging modalities such as harmonic imaging and pulse inversion imaging reduce Doppler artifacts and allow real time detection of the microbubbles flowing in the blood stream. Future directions include ultrasound-guided therapy of occlusion using encapsulated drugs targeted to the thrombus.
Blood Flow Velocity↗
beta-Hexosaminidase isoenzymes A and B in middle-aged and elderly subjects: determinants of plasma levels and relation to vascular disease.
Plasma/serum beta-hexosaminidase (Hex) activity is known to be increased in chronic alcoholism, liver disorders, pregnancy and diabetes mellitus. Hex activity also shows an association with risk factors for vascular disease and heredity for arteriosclerosis. There are several isoenzymes of Hex. Using an enzyme immunoassay for Hex isoenzymes (Hex A and Hex B) we studied possible determinants of Hex isoenzymes and their relation to vascular disease in randomly invited (n = 244) 35-95-year-old men and women. In both sexes there were significant age-related increases in Hex activities and men exhibited higher activity of both isoenzymes. Both Hex isoenzymes correlated with age, systolic blood pressure, serum triglycerides and liver enzymes, whereas Hex A was distinguished from Hex B by its stronger correlation with blood glucose. In multiple linear regression analysis Hex A was explained to 20.7% by blood glucose, age, serum aspartate aminotransferase and glutamyl transpeptidase. Hex B was explained to 14% by age, serum glutamyl transpeptidase and serum triglycerides. There was no significant increase in Hex isoenzymes in subjects with hypertension, diabetes mellitus or myocardial disease, nor did current smokers exhibit any increase of these enzymes compared to non-smokers. The main conclusion in that liver function, as reflected by the level of liver enzymes and glucose metabolism, is the major determinant for Hex isoenzymes in plasma.
Adult↗
Atherosclerosis and vascular disease: effects of peptide mimetics of apolipoproteins.
Levels of high density lipoprotein (HDL) and its major protein component, apolipoprotein (apo) A-I, are strongly inversely correlated to risk of atherosclerosis and other vascular diseases. A number of properties of apo A-I may contribute to this protection, including removal of cholesterol from peripheral tissues to the liver (reverse cholesterol transport), anti-inflammatory and anti-oxidative activities, and modulation of vascular function. Apo A-I has lipid-associating domains that form class A amphipathic helices. Peptide analogs that have no sequence homology to the domains in apo A-I but possess the class A motif have been shown to not only associate with phospholipid but also mimic several of the functional properties of apo A-I. Peptide 4F, with four phenylalanines on the non-polar face, was found to be maximally effective in mimicking the positive qualities of apo A-I; this peptide inhibited atherosclerosis, reduced inflammation and oxidation, and improved vascular function in a number of animal models, and when synthesized with D-amino acids is orally bioavailable. Several other classes of peptide mimetics are now being studied, and may contribute to our understanding of the functions of apo E and apo J. The use of peptide mimetics to study apolipoprotein function has proved to be a powerful tool, and may lead to novel therapeutic agents in the prevention of atherosclerosis and other vascular diseases.
Animals↗
Can the birth of a large infant predict risk for atherosclerotic vascular disease in the mother?
We have previously demonstrated that women who had given birth to large infants had a six-fold increased risk of developing Type 2 (non-insulin-dependent) diabetes mellitus compared with a control group matched for age and parity. However, the patients were extremely obese which explained, in part, the increased risk. In the present investigation we studied whether the delivery of large infants correlated with risk factors for atherosclerotic vascular disease other than obesity and diabetes, and therefore could serve as early markers for syndrome X. The study consisted of 73 women who 20-27 years earlier had given birth to large infants weighing 4,500 g or more. Another group of 73 women matched for age, parity and BMI who had delivered infants weighing less than 4,500 g within a 3-month period served as a control group. Of these 73 patient/control pairs, 48 (66%) were able to participate in the investigation. Mean age was 52.2 years (range 40-66 years). No differences were noted for family history of diabetes and medication prescribed for vascular disease between the groups. An oral glucose tolerance test was performed and glucose, insulin and C-peptide at 0 and 2 h were estimated. Triglycerides, cholesterol, LDL and HDL cholesterol were analysed at baseline. We found no tendency towards hyperinsulinaemia and hyperglycaemia in the patients and both groups had the same relative increase in levels of insulin and C-peptide. No difference between the groups regarding manifest symptoms of vascular disease, either in blood pressure or in proteinuria were observed.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Anticardiolipin antibodies and occlusive vascular disease of the eye: prospective study.
There is a recognized association between the presence of anticardiolipin antibodies and vascular occlusive disease. The purpose of our study is to detect the presence of high titers of anticardiolipin antibodies (ACA) in the serum and to correlate the titers with the severity of the vascular disease in patients with occlusive ocular vascular disease. 82 patients were included in a prospective study; 25 patients with anterior ischaemic optic neuropathy, 36 with retinal vein occlusion and 21 with retinal artery occlusion. ACA (IgG and IgM isotypes) were measured by ELISA in the sera of all patients. The group of the patients (group A) was compared to an age-matched control group of 79 healthy individuals (group B). IgG isotype (but not IgM) titers of ACA were found significantly higher in group A (P < 0.001). In patients with titers of ACA (IgG isotype) > 100 units we noted a higher incidence of a more severe disease (recurrency, involvement of both eyes or extraocular manifestations) especially among those with anterior ischaemic optic neuropathy and secondarily in those with retinal artery occlusion. Our results suggest that the association between high titers of ACA and occlusive vascular disease of the eye concerns only the IgG isotype. In addition, the detection of high titers of IgG/AGA in patients could be a useful marker for disease severity and prognosis and this observation seems to be more explicit in cases with arterial occlusive disease than in cases with venous occlusive disease.
Adult↗
Noninvasive radionuclide assessment of cardiac function in patients with peripheral vascular disease.
Disorders of the peripheral vascular system often are associated with heart disease which may increase operative risk. The purpose of this study was to investigate the clinical usefulness of radionuclide angiocardiography for evaluation of cardiac function in patients with vascular disorders. This simple procedure provides measurements of cardiac output, pulmonary blood volume, and left ventricular end-diastolic volume, stroke volume, and ejection fraction with no significant risk or discomfort to the patient. A total of 22 patients with vascular disorders were studied by this technique. Five patients had systemic arteriovenous malformations. The cardiac output, end-diastolic volume, and stroke volume were documented to be greater than normal in these patients before operation. In three patients studied following closure of the arteriovenous fistula, the cardiac output, left ventricular end-diastolic volume, and stroke volume decreased. Postoperative changes in left ventricular ejection fraction were variable. A group of 17 patients with atherosclerotic vascular disease underwent cardiac evaluation. In nine patients with no history of cardiac disease, the lowest ejection fraction of 0.45 occurred in a patient with a saccular thoracic aneurysm, the only patient of the 22 who died after operation. A wide variation in ejection fraction was observed in patients with a history of cardiac disease which ranged from 0.32 to 0.86. Objective documentation of cardiac function by radionuclide angiocardiography would appear to enhance the management of patients with peripheral vascular disorders.
Adult↗
Interobserver agreement on captopril renography for assessing renal vascular disease.
UNLABELLED: Captopril-stimulated renography is widely used to screen selected groups of hypertensive patients for renal vascular disease. Evaluation of the test is a complex task. Lack of interobserver agreement on the assessment and interpretation of renographic parameters may contribute to differences in sensitivity and specificity between studies. METHODS: Three experienced nuclear medicine physicians evaluated 658 renograms of 503 hypertensive patients suspected of having renal vascular disease from a large Dutch multicenter study (the Dutch Renal Artery Stenosis Intervention Cooperative [DRASTIC] study). Interobserver agreement on several renographic parameters was assessed by the kappa statistic and the intraclass correlation coefficient (ICC). RESULTS: The interobserver agreement on the time to excretion was high: The pooled ICC was 0.90. The pooled kappa was > or = 0.65 for the pattern of the time--activity curves, the visual aspect of the scintigraphic images (visible uptake and kidney size), and the judgment on the presence of renal artery stenosis. However, the interobserver agreement on cortical retention and pelvic retention by visual inspection of the images was rather low (pooled kappa = 0.46 and 0.52, respectively). Pelvic retention was found to complicate the interpretation of renography. CONCLUSION: Interobserver agreement on most of the renographic parameters was satisfactory, but the assessment of cortical retention was more difficult, in particular, in the presence of pelvic retention. Captopril renography should be interpreted with caution if pelvic retention is suspected. Interobserver variability offers one of several explanations for the differences in diagnostic test performance that are found between studies.
Adolescent↗
Fatty acid metabolism and vascular disease.
Fatty acid metabolism is abnormal in insulin-resistant states that increase the risk of atherosclerosis such as type 2 diabetes and the metabolic syndrome. How fatty acids promote vascular disease is poorly understood, but lipoprotein lipase and peroxisome proliferator-activated receptor alpha (PPARalpha)-physiologically related proteins involved in fatty acid metabolism-may be involved. Glucocorticoid metabolism is also abnormal in insulin-resistant states and may promote several components of the metabolic syndrome. Recent studies have shown that hepatic fatty acid metabolism is required for the development of insulin resistance and hypertension caused by glucocorticoid excess, suggesting that crosstalk between glucocorticoid receptor-and PPARalpha-dependent pathways may contribute to vascular disease.
Animals↗
Correlation of platelet aggregation, plasma factor activity, and megathrombocytes in diabetic subjects with an without vascular disease.
Second-phase platelet aggregation induced by adenosine diphosphate (ADP) and epinephrine was measured in fasting platelet-rich plasma in normals, "prediabetics," and diabetics with or without vascular disease. "Plasma factor" potentiation of ADP-induced second-phase platelet aggregation was also estimated, as were megathrombocyte numbers in the same patient groups. There was an increased sensitivity of second-phase platelet aggregation noted with both aggregating agents in all diabetic groups except for the prediabetics. This activity was paralleled by an increase in plasma factor activity. In vivo evidence of an increased turnover of platelets in frank diabetics was suggested by increased numbers of megathrombocytes. These studies demonstrate that platelets from diabetics are sensitive to aggregating agents and that this sensitivity may be related to plasma factor(s) present in diabetics. In vivo platelet aggregation may be present in diabetics. Longitudinal studies will be necessary to establish the relationship of these findings to the genesis of diabetic vascular disease.
Adult↗
Trends in the incidence of end-stage renal failure due to hypertension and vascular disease in Australia, 1972-1991.
BACKGROUND: Despite the known protective effects upon renal function of lowering blood pressure in primary chronic renal disease, diabetes and malignant hypertension, the number of patients entering dialysis and transplantation programmes with renal failure due to hypertension or vascular disease remains high. AIMS: To analyse the trends in incidence of arteriopathic end-stage renal failure. METHODS: Calculation of mean annual age- and sex-specific rates (by decade) and truncated age-standardised rates for entry into Australian end-stage renal failure programmes in the period 1972-1991. Statistical analysis by chi-squared test, assuming a Poisson distribution of cases. RESULTS: End-stage renal failure attributed primarily to hypertension or vascular disease fell to less than half its former level over the period of observation in persons aged 15-54 years. This change has occurred only in the diagnostic category 'malignant hypertension'. Trends in persons aged 55 years and over are more difficult to analyse because of changing criteria for entry into renal failure programmes, but there has been no indication of any fall in incidence. CONCLUSIONS: The aetiology and pathology of arteriopathic renal failure is diverse, with different patterns in young and old adults. The formerly common pathology in young adults is largely preventable by modern antihypertensive therapy, while arteriopathic renal disease in older persons is not.
Adolescent↗