Visualization of renal arteries and value of color-coded duplex sonography in renal artery stenoses using an ultrasound signal enhancing agent]

OBJECTIVES: To examine whether a second-generation perfluorocarbon (PFC) blood substitute added to the cardiopulmonary bypass (CPB) prime influences complement production. DESIGN: A prospective, randomized, single-blinded, ex vivo model. SETTING: A university hospital, laboratory, and clinics. PARTICIPANTS: Ten healthy adult consented volunteer blood donors (five men, five women). INTERVENTIONS: Ex vivo closed-loop extracorporeal circuit including membrane oxygenator, tubing, and filter primed with crystalloid or crystalloid plus PFC was circulated for 1 hour with the addition of 500 mL of heparinized fresh human whole blood. MEASUREMENTS AND MAIN RESULTS: Laboratory specimens were drawn from the circuit at 10-minute intervals for 1 hour and measured for complement (C3a, Bb fragment) concentrations, blood gases, fibrinogen concentration, platelet count, and hematocrit. In the PFC group, C3a and Bb fragments were equal to or less than those in the group that received crystalloid alone. CONCLUSION: The second-generation PFC added to the prime of a CPB circuit does not independently increase complement production.     

Study of atheromatous stenoses of carotid bifurcations by Doppler ultrasound, spiral angio-MRI, magnetic resonance angiography and comparison with arteriography

PURPOSE: To evaluate Doppler ultrasound (US), Helical CT, Magnetic Resonance (MR) angiography in the detection of carotid bifurcation atherosclerotic disease and comparison with angiography. MATERIALS AND METHODS: After a Doppler US procedure, 56 carotid bifurcations were included (symptomatic stenosis greater than 60% or asymptomatic stenosis greater than 30%). Helical CT, MR angiography and selective arteriography were performed. Stenosis were measured with NASCET criteria. Sensitivity and specificity were calculated and compared to arteriographics findings for each procedure and each grade of stenosis. RESULTS: Helical CT and MR angiography had their best sensitivity in grade 3 (70-99%), 92%, 100% respectively, their specificity was identical (91%). All the occlusions were depicted by the three procedures. CONCLUSION: Association of Doppler US and MR angiography may replace in the future selective angiography in the evaluation of extracranial atherosclerotic disease. Arteriography would be performed only in case of discordance between these two procedures.     

Relationship between haemodynamics and morphology in pulmonary hypertension. A quantitative intravascular ultrasound study

BACKGROUND: Intravascular ultrasound imaging of the pulmonary arteries has been demonstrated to be a reliable method of quantifying vessel diameter, luminal area and pulsatility. Simultaneous measurement of flow velocity and its response to vasodilators allows the relationship between morphology and functional compromise to be studied, especially endothelial dysfunction. METHODS: In 51 patients (mean age = 49.8 +/- 12.6 years, 17 female) we performed right heart catheterization and simultaneous intravascular ultrasound of pulmonary artery branches. The patients were divided in two groups: group 1 with normal pulmonary artery pressure and pulmonary vascular resistance, and group 2 with pulmonary hypertension (peak pulmonary artery pressure > 30 mmHg and/or mean pulmonary artery pressure > 20 mmHg). Vessel wall and lumen were studied using a 2.9 F intravascular ultrasound catheter with a 30 MHz phased array transducer. Measurement of blood flow velocity was accomplished by a Doppler flow wire (0.018 inch). The maximal flow change during acetylcholine infusion (adjusted to 10(-6); 10(-5), and 10(-4) M concentration in the blood vessel) was measured. RESULTS: There were no significant differences between groups 1 and 2 with respect to age (48.5 +/- 14.3 years vs 50.3 +/- 12.3 years; P = ns), gender (4 female/8 male vs 13 female/26 male; P = ns), luminal area of the vessel segment in which the intravascular ultrasound measurements were obtained (11.8 +/- 6.1 mm2 vs 16.7 +/- 14.3 mm2; P = ns), internal diameter (3.9 +/- 1.2 mm vs 4.2 +/- 1.7 mm; P = ns), and external diameter (6.1 +/- 1.3 mm vs 6.9 +/- 2.1 mm; P = ns). Cross-sectional images of the pulmonary artery wall demonstrated a single ring with high echodensity with a thin inner layer regarded as intima in group 1. In contrast, the majority of patients (n = 35/39) in group 2 demonstrated a thickening of the intimal layer and/or a disturbance of layering of the echogenic arterial wall. The relative wall thickness was higher in group 2 than in group 1 (22.5 +/- 10.4% vs 15.3 +/- 6.5%; P < 0.05). There were no significant correlations between pulmonary artery pressure and wall thickness pulmonary artery pressure and area change in the cardiac cycle, acetylcholine-dependent increase in pulmonary flow and morphological changes in the vessel wall. CONCLUSION: We conclude that intravascular ultrasound is capable of detecting morphological changes in the pulmonary vessel wall in pulmonary hypertension and that vessel wall hypertrophy of small pulmonary segment arteries, as detected by intravascular ultrasound, is not predictive of functional vasodilatory response of resistance vessels of the same vessel area.     

The development of valvular incompetence after deep vein thrombosis: a follow-up study with duplex scanning

PURPOSE: Duplex ultrasonography with distal cuff deflation was used to establish the physiologic reflux duration in different segments of the deep venous system in healthy individuals, and to document the occurrence of deep vein valve incompetence in patients after deep vein thrombosis (DVT). METHODS: Two hundred fifty-two vein segments in 42 legs of 21 healthy individuals and 160 deep vein segments in 27 patients with phlebographically documented DVT were examined with duplex scanning. RESULTS: The duration of reflux in healthy subjects was significantly shorter in distal deep vein segments. Ninety-five percent of the values were less than 0.88, 0.8, 0.8, 0.28, 0.2, and 0.12 seconds, respectively, for the common femoral, superficial femoral, deep femoral, popliteal, and posterior tibial vein (at midcalf and ankle level). The 95 percentile for reflux duration in the superficial venous system was 0.5 seconds for all vein segments, regardless of the location. No significant correlation was found between the reflux peak flow velocity and reflux duration (R = 0.6). The reflux peak flow velocity is therefore not useful as a parameter of the degree of reflux. The patient group was examined with an interval of 18 to 51 months (mean 34 months) after DVT. Forty-five percent of the initially affected segments showed valve incompetence at follow-up (n = 54); only three of 40 segments initially free from thrombus showed pathologic reflux at follow-up (p < 0.01). Reflux durations in most of the incompetent vein segments were two or more times the normal value of reflux duration. The highest prevalence of valve incompetence was found in the superficial femoral and popliteal vein segment (p < 0.01). None of the patients showed valve incompetence at all levels of the deep venous system. A significant (p = 0.04) relation was found between the extent of the initial thrombosis and the number of refluxing vein segments at follow-up, but no correlation was found between the extent of initial thrombosis and the late clinical symptoms (p = 0.16); clinical symptoms could not be related to the number of incompetent vein segments. CONCLUSIONS: Duplex scanning allows a good discrimination between physiologic and abnormal reflux duration and is an important tool in the evaluation of the postthrombotic limb. Early assessment after DVT may have prognostic value in individual patients.     

Automatic segmentation of intravascular ultrasound images: a texture-based approach

Extraction of blood vessel boundaries from intravascular ultrasound images is essential in the quantitative analysis of cardiovascular functions. In this study, we are presenting a completely automated procedure for determining blood vessel borders. This approach uses textural operators to separate different tissue regions and morphological processing to refine extracted contours. The method was tested in a set of 29 intravascular ultrasound images obtained in vivo. To assess the performance of the method, we have compared the automatically processed images with the manual tracings, using three different criteria: correlation coefficient, match ratio, and relative error of computed shape parameters. In both contour detection and shape parameters estimation, the proposed method yielded consistently good results. Due to its robustness and accuracy, this approach is appropriate for clinical use, whereas computational efficiency of the method facilitates low-cost implementation.     

Intimal hyperplasia thickness at follow-up is independent of stent size: a serial intravascular ultrasound study

The purpose of this study was to determine whether the thickness of the intimal hyperplasia (IH) layer that accumulates within Palmaz-Schatz stents is dependent on stent size. Intravascular ultrasound (IVUS) and quantitative angiographic (QCA) studies were performed after stent implantation and at follow-up (5.4 +/- 3.8 months) in 161 patients with 177 lesions treated with 221 Palmaz-Schatz stents. Stent and lumen cross-sectional area (CSA) were measured. IH CSA and thickness at follow-up were calculated and compared with stent CSA and circumference. Maximum IH CSA and thickness were measured at the smallest follow-up lumen CSA; mean IH CSA and thickness was averaged over the length of the stent. Maximum IH CSA measured 4.8 +/- 2.4 mm2, and mean IH CSA measured 2.8 +/- 2.2 mm2. Maximum IH thickness (at the smallest follow-up lumen CSA) measured 0.60 +/- 0.36 mm, and mean IH thickness (over the length of the stent) measured 0.30 +/- 0.19 mm. There was a weak, but significant correlation between mean and maximum IH CSA versus stent CSA (r = 0.215, p <0.0001 and r = 0.355, p <0.0001, respectively). However, there was no correlation between mean or maximum IH thickness versus stent CSA (r = 0.018, p = 0.643 and r = 0.056, p = 0.463, respectively) or stent circumference (r = 0.002, p = 0.956 and r = 0.069, p = 0.361, respectively). IH thickness was found to be independent of the stent size. This explains the known higher frequency of restenosis in smaller stents compared with larger stents.     

Measurement of plaque volume using three-dimensional intravascular ultrasound: in vitro study]

Sunlight causes acute toxic effects such as sunburn, local and systemic immune suppression, and long-term adverse effects including photoaging and skin cancer. The degree of damage depends on the overall exposure-dose and individual susceptibility. Various strategies should be employed to minimize sun-exposure damage, including proper use of sunscreens and exposure avoidance. Public education might best be focused on protecting children and promoting awareness of photoaging changes in adults.     

Results of percutaneous transluminal angioplasty for atherosclerotic renal artery stenosis: a follow-up study with duplex ultrasonography

The electrographic features of successful sites of radiofrequency catheter ablation were analyzed in 33 cases of posteroseptal accessory pathways and compared with those from 155 cases of free wall accessory pathways. The atrioventricular intervals in the posteroseptal cases were significantly longer than in the free wall cases (posteroseptal vs left and right free wall; 38 vs 33 and 26 msec, respectively; p < 0.05), and the incidences of continuous electrograms (42 vs 63 and 79%; p < 0.01) and PQS-pattern unipolar electrograms (50 vs 76 and 78%; p < 0.05) were significantly lower in the posteroseptal cases. The V-delta intervals in the posteroseptal cases were significantly longer than in the left free wall cases (17 vs 13 msec; p < 0.05), but shorter than in the right free wall cases (17 vs 23 msec; p < 0.05). No statistically significant difference in the incidence of Kent potentials among the 3 groups was observed. In radiofrequency ablation of posteroseptal pathways, the length of the atrioventricular interval and the incidences of continuous electrograms and PQS-pattern unipolar electrograms may be unsatisfactory even at the appropriate target site, but the V-delta interval and Kent potential are good indicators of suitable target sites.     

Experimental ligation versus embolization of the external carotid artery: a comparative hemodynamics study

Patterns of collateral vascularization were investigated by SEM evaluation of microvascular corrosion casts following either ligation or embolization of the external carotid artery in the rabbit. Results indicated that rich collateral channels were established soon after ligation of this artery, and blood supply to the lesional area was never cut off. In contrast, embolization effectively obstructed blood supply by reducing collateral branches. We concluded that for purposes of controlling blood loss, it is more helpful to employ external carotid embolization rather than ligation for oral maxillofacial lesions with a rich blood supply.     

Arterial remodeling after balloon angioplasty of the coronary artery: an intravascular ultrasound study. PICTURE Investigators. PostTreatment IntraCoronary Transluminal Ultrasound Result Evaluation

OBJECTIVE: Before balloon dilation, failure of compensatory enlargement and even arterial shrinkage are frequently observed at the lesion site in response to plaque accumulation. Balloon angioplasty may be regarded as artificial remodeling to enlarge the artery. The prevalence of the different types of arterial wall remodeling after applied stretch by balloon angioplasty is unknown. METHODS AND RESULTS: In 181 patients an intravascular ultrasound study was performed after coronary balloon angioplasty (n = 200 lesions). The vessel area was measured at a proximal and distal reference site and at the lesion site. Subsequently, the relative vessel area [(Vessel area lesion site)/Vessel area reference site) x 100] was calculated. Lesions were classified in three groups on the basis of their relative vessel areas: > or =105%, <105% but >95%, and < or =95%. A relative vessel area > or =105%, indicating enlargement compared with the reference site, was observed in 84 (44%) lesions. A relative vessel area <105% but >95% was observed in 43 (22%) lesions. A relative vessel area < or =95%, indicating "shrinkage" compared with the reference site, was observed in 66 (34%) lesions. CONCLUSIONS: After balloon angioplasty, the vessel area was found to be smaller compared with the reference site in 34% of the lesions. This small vessel area at the lesion site compared with a reference site may be a reflection of insufficient stretch by balloon angioplasty.     

Surgical management of concurrent, coeliac and bilateral iliac artery aneurysms

A 76-year-old man was admitted with bilateral common iliac artery aneurysms found incidentally on computed tomography. Transfemoral digital subtraction arteriography demonstrated atherosclerotic plaques in the aorta with bilateral common iliac artery aneurysms and a coeliac axis aneurysm. The coeliac artery aneurysm was resected and an aortobifemoral bypass performed with reimplantation of the inferior mesenteric artery into the prosthesis. The patient was well when discharged 2 weeks after operation. The incidence, natural history and management of coeliac axis and iliac artery aneurysms are reviewed.     

Risk factors and clinical outcomes between fungal and bacterial keratitis: a comparative study

OBJECTIVE: Thirty years ago, cardiopulmonary resuscitation (CPR) was primarily developed for otherwise healthy individuals who experienced sudden cardiac arrest. Today, CPR is widely viewed as an emergency procedure that can be attempted on any person who undergoes a cessation of cardiorespiratory function. Therefore, the appropriateness of CPR has been questioned as a matter of the outcome, the patient's preferences, and the cost. The objective of this article is to analyse ethical issues in prehospital resuscitation. ARGUMENTS: CPR is bound by moral considerations that surround the use of any medical treatment. According to Beauchamp and Childress, the hierarchy of justification in biomedical ethics consists of ethical theories, principles, rules, and particular judgements and actions. The decision to start CPR is based on the medical judgement that a person is suffering from circulatory arrest. The decision is justified by the moral rule that the victim of a cardiac arrest has the right to survive and to receive CPR. Moral rules are more specific to contexts and are based on ethical principles. The principle of beneficence means the provision of benefits for the promotion of welfare. Talking about beneficence in resuscitation means once again reporting stories of success, as many victims of pre- and in-hospital sudden death have been saved in the past. Nevertheless, resuscitative efforts still remain unsuccessful in the majority of cases, involving the principle of nonmaleficence. There is potential harm in CPR. Survivors may recover cardiac function, but sustain severe hypoxic brain damage, at worst surviving without awakening for months or years. In particular, post-traumatic CPR is associated with an extremely poor outcome, leading to the issue of futility. However, futility should be defined in a strict fashion, as there might be an individual chance of survival. The principle of respect for autonomy means the right of a patient to accept or reject medical treatment, which continues in emergency conditions and after the patient has lost consciousness. The time frame in CPR requires medical decision-making within seconds, and CPR is usually initiated without the patient's involvement. If the patient's wish's can be ascertained later on, life-sustaining therapies might be withdrawn at the time. Terminally ill but still competent patients should be encouraged to write a no-CPR document, which does not deny patients relief from severe symptoms, but might facilitate withholding resuscitative efforts at the scene. The principle of justice affects priorities in the allocation of health care resources. The decision made for a particular patient might delay or prevent emergency treatment in other patients who could receive greater benefit. CONCLUSIONS: The standard of care remains the prompt initiation of CPR. However, ethical principles such as beneficence, nonmaleficence, autonomy, and justice have to be applied in the unique setting of emergency medicine. Physicians have to consider the therapeutic efficacy of CPR, the potential risks, and the patient's preferences.     

The incidence of iliac, femoral, and popliteal artery aneurysms in hospitalized patients

PURPOSE: Previous studies have attempted to determine the incidence and mortality rate of abdominal aortic aneurysms in a variety of populations; however, the incidence of iliac, femoral, and popliteal artery aneurysms have not been established. The objective of this study was to determine the incidence of lower extremity aneurysms in hospitalized patients in the state of Utah, which has a population at low risk for cardiovascular disease, atherosclerosis, and smoking, and to compare the results with the incidence in the United States. METHODS: Incidences of iliac, femoral, and popliteal artery aneurysm in Utah were determined over a 6-year period, with data obtained via diagnostic codes from the Utah Hospital Association. The incidence of iliac, femoral, and popliteal artery aneurysms in the United States hospital population was calculated by use of National Hospital Discharge Summary 1990 data, a complex sample of nonfederal short-stay hospitals in the United States, which provides the most comprehensive database of health statistics in the United States. RESULTS: The incidence of iliac femoral/popliteal artery aneurysms in hospitalized Utah men is 3.76 and 4.85 per 100,000 population, respectively. In American men, iliac and femoral/popliteal artery aneurysm incidences are 6.58 and 7.39 per 100,000 population, respectively. Incidences among hospitalized women in Utah are 0.24 and 1.07 per 100,000; incidences in women in the United States are 0.26 and 1.00 per 100,000, respectively. The incidence of nonaortic peripheral aneurysms among hospitalized patients in Utah is lower than in the United States. The rate ratios (Utah/United States) for incidences of iliac, femoral, and popliteal artery aneurysms in men are 0.57 and 0.66, respectively (p < 0.05). No statistical difference is seen between incidences in women in Utah and the United States (p > 0.05)-ratios of 0.93 and 1.06, respectively. CONCLUSION: This study validates the traditional belief that iliac, femoral, and popliteal artery aneurysms are much less frequent, at least in hospitalized patients, than previously published incidences of abdominal aortic aneurysms.     

Brachymesophalangia-V in five samples of children: a descriptive and methodological study

The occurrence of brachmesophalangia-V (BMP-V) in 2,012 individuals from five samples of children of different ethnic backgrounds was determined using two indices. Frequencies of BMP-V were analyzed for three variants: BMP-V alone, BMP-V with clinodactyly, and BMP-V with a cone-shaped epiphysis. The two indices used to identify BMP-V indicated highest relative frequencies among Mexican children, moderate frequencies among children of European ancestry (Pennsylvania White, Canadian, West German), and lower frequencies in Pennsylvania Black children. Index 1, based on the ratio of the width to the length of the fifth mid-phalanx, consistently produced higher frequencies than Index 2, based on the ratio of the length of the fifth to the length of the fourth mid-phalanges. Index 1 was also more selective of BMP-alone, while Index 2 selected primarily BMP-V with clinodactyly and/or cone-shaped epiphyses. The differences between indices were largely due to the fact that Index 1, which basically defines shape, selected both the shortest and/or widest mid-phalanges, while Index 2 related actual length differences. It is suggested that Index 2 provided a more suitable criterion of BMP-V in comparative studies, due to possible population differences in phalangeal shape.     

Extent and distribution of atherosclerotic plaque in relation to major coronary side-branches: an intravascular ultrasound study in vivo

BACKGROUND: The non-uniform extent and distribution of atherosclerotic plaque at bifurcations have been described by necropsy studies and they are related to local blood-flow disturbances. Systematic evaluation of plaque extent and distribution upstream and downstream of major coronary side-branches has not yet been evaluated in vivo. METHODS: We used intravascular ultrasound imaging in 41 patients with atherosclerotic disease to study the region of 73 major coronary side-branches at 2 mm increments proximal and distal to the side-branch (657 images: 73 at origin of side-branch; 292 proximal; 292 distal). The maximum (MXT) and minimum (MINT) plaque thickness and the plaque burden percentage (% PB) were measured in all the segments. The angle of distribution of maximum plaque thickness with respect to the origin of the side-branch was determined in each cross-section and assigned to S1 when located on the semicircle in the direction of the origin of the side-branch and to S2 when located on the opposite wall. RESULTS: The mean value of maximum plaque thickness and the plaque burden percentage were similar at the origin and in the two adjacent segments proximal and distal to the side-branch (1.0 +/- 0.48 mm, 1.06 +/- 0.48 mm and 0.98 +/- 0.48 mm; 45 +/- 19%, 46 +/- 19% and 44 +/- 18%). In distal sites of analysis, the plaque was more frequently eccentric in comparison to proximal sites (presence of an arc of plaque-free wall: 79% versus 62% in very distal and in very proximal sites respectively; p < 0.05). The prevalence of maximum plaque in S2 was higher at the origin (84%) and in adjacent distal segments (86%) as compared with the adjacent proximal segments (60%; p < 0.0001). CONCLUSIONS: The distribution of plaque is influenced by the origin of a major coronary side-branch in patients with coronary atherosclerosis: in distal sites the location of maximum plaque is almost always eccentrically distributed on the wall opposite the take-off.     

Studies of correlation between progression of coronary artery disease, as assessed by coronary arteriography, left ventricular end-diastolic pressure, ejection fraction, and employability

The occupational status of a group of 100 male patients, 35 to 68 years of age, with chronic ischaemic heart disease was studied, and related to the severity and distribution of coronary artery stenosis seen on the arteriograms and to left ventricular function. In this series of patients 31 per cent were working, 31 per cent were recorded as temporarily sick, and 38 per cent as permanently disabled. It appears that while the type of previous occupation and physical activity associated with the job were of importance, there was no correlation between employability on the one hand and severity and distribution of coronary artery disease on the other. 'Blue-collar' workers had a higher rate of unemployment than those in 'white collar' occupations, but this could not be explained by differences in severity of coronary artery disease.