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At least 1,369 records · Page 76Linked to original sources
PubMed2001

Relationship between vascular enhancement, cerebral hemodynamics, and MR angiography in cases of acute stroke.

BACKGROUND AND PURPOSE: The use of MR angiography and contrast-enhanced T1-weighted MR imaging in cases of acute cerebral ischemia may be helpful in the evaluation of middle cerebral artery (MCA) occlusion and leptomeningeal collaterals, respectively. The aim of our work was to investigate the relationship between MCA occlusion, T1-weighted vascular contrast enhancement, hemodynamic alterations, and tissue damage in cases of acute ischemic stroke. METHODS: We studied the MCA territory in 15 patients with acute ischemic stroke within 8 hr of symptom onset. The first MR imaging study (<8 hr after onset) comprised diffusion-weighted imaging, MR angiography, perfusion-weighted imaging, and contrast-enhanced T1-weighted MR imaging sequences. Follow-up MR imaging, performed 1 week later, consisted of MR angiography and T2-weighted fluid-attenuated inversion recovery MR imaging. RESULTS: Early MR angiography showed MCA stem occlusion in nine of 15 patients. Patients with MCA occlusion had significantly larger areas of abnormality on early diffusion-weighted images, significantly larger areas of altered hemodynamics, larger final lesion volumes, and poorer clinical outcome. Among the nine patients with MCA stem occlusion, vascular enhancement was marked in seven and absent in two who had complete MCA infarcts and poor clinical outcome. Among patients with MCA patency, vascular enhancement was marked in only one, mild in four, and absent in one. Patients with marked vascular enhancement had significantly larger regions of altered hemodynamics and significantly higher asymmetries in both regional cerebral blood volume and mean transit time because of increased values in the affected hemisphere. CONCLUSION: Among patients with stroke with MCA occlusion, marked vascular enhancement and increased blood volume indicate efficient leptomeningeal collaterals and compensatory hemodynamic mechanisms.

Aged↗
PubMed2001

[A new organization model for hemodynamic cardiology diagnosis and intervention cardiology].

In centers without hemodynamic laboratories the quality of medical care may be suboptimal since the unavailability of these technologies may reduce medical experience in the treatment of heart disease, mostly in acute coronary syndromes, and may increase the need for referring some patients to other hospitals. The problem will be of great relevance in the case of expansion of the aggressive approach in the treatment of acute ischemic syndromes such as acute myocardial infarction and unstable angina. The impelling need for small centers of improving medical care may promote the spontaneous and uncontrolled proliferation of hemodynamic laboratories. The high number of hemodynamic laboratories may lead to a low institutional volume and, as a consequence, may negatively influence the outcome of coronary intervention and increase health care costs. The experience of operators and the costs are probably more relevant as regards angioplasty than coronary angiography. Therefore we propose the implementation of departments of interventional hemodynamic laboratories including different hospitals: diagnostic laboratories will be allocated in hospitals with coronary care units, while interventional laboratories will be allocated in referring hospitals.

Coronary Care Units↗
PubMed2000

Role of autonomic nervous system and hemodynamics in cardiovascular homeostasis after orthostatic stress.

Autonomic control of hemodynamics is crucial to maintaining cardiovascular homeostasis after orthostasis. Our goal was to assess the effect of passive orthostatic stress on cardiovascular hemodynamics regulation by analysis of the autonomic nervous system (ANS) and gender influence on the variables. We used a passive 70 degrees tilt test as an orthostatic maneuver. For SNA measurements we used FFT for HRV and SBPV, temporal sequences and alpha index to calculate baroreceptor gain. Hemodynamic data was calculated non-invasively by modelflow. Orthostatic stress induces a rise in heart rate (+15%), total peripheral resistance (+28%), sympathetic tonus (LF_nu: +32%; LF_pas: +64%) and a reduction in cardiac output (-28%), systolic volume (-43%), and vagal activity both tonic (HF_nu:-115%) and reflex (BRG:-103%). Females had higher vagal activity regardless of position. We concluded that the autonomic nervous system plays a crucial role in cardiovascular hemodynamics control to maintain homeostasis after orthostatic stress.

Adult↗
PubMed2001

Comparison of midazolam with or without fentanyl for conscious sedation and hemodynamics in coronary angiography.

OBJECTIVE: To compare the hemodynamic and sedative effects of midazolam - with or without fentanyl combination - with placebo in coronary angiography. DESIGN: Prospective, double-blind, randomized study. SETTING: University medical centre. PATIENTS: All patients undergoing coronary angiography. INTERVENTIONS: Demographic data, hemodynamic variables, sedation and anxiety scores, amnesia, patient and cardiologist satisfaction, and adverse effects were evaluated and compared among coronary angiography patients taking midazolam, midazolam and fentanyl, or placebo before the procedure. MAIN RESULTS: Ninety patients scheduled for coronary angiography were randomly assigned into three groups: a midazolam-placebo group (group MP), a midazolam-fentanyl group (group MF) and a placebo group (group P). Hemodynamic stability was better in each sedation group (groups MP and MF) than in group P. Sedation scores, anxiolysis, and patient and cardiologist satisfaction were not different between the sedation groups. CONCLUSIONS: Both techniques of conscious sedation - midazolam and midazolam with fentanyl - are satisfactory for coronary angiography where hemodynamic stability and patient cooperation are required. In such procedures, local anesthesia without sedation may lead to hypertension and increase overall morbidity.

Adult↗
PubMedDate not supplied

[Hemodynamic status of the mother and fetus in pregnant women with gestosis during abdominal delivery under different anesthesia methods].

Pregnants in the third trimester with medium- and severe gestosis were divided into 3 groups according to types of maternal and fetal hemodynamics: 1) controls (n = 58 pts); 2) eukinetic type (n = 54 pts); and 3) hypokinetic type (n = 55 pts). Each group was subdivided into 3 subgroups according to administered types of anesthesia for cesarean section (epidural, spinal, and general). Central hemodynamics of the mother, fetus, and fetoplacental complex was studied. Use of different anesthesias in woman with normal pregnancy did not affect the hemodynamics, and therefore any type of anesthesia can be used in cesarean section. In pregnants with gestosis, the eukinetic hemodynamic and compensated or subcompensated placental insufficiency the optimal anesthesia was epidural and spinal. For pregnant with hypokinetic circulation and subcompensated or decompensated placental insufficiency epidural anesthesia is preferable.

Algorithms↗
PubMed2001

[The effects of milrinone on hemodynamics in patients undergoing cardiac surgery].

The phosphodiesterase inhibitor, milrinone is used to treat low cardiac output syndrome, especially after cardiac surgery. But there were few reports about the precise hemodynamic effects at separation from cardiopulmonary bypass (CPB). We examined the hemodynamic effects of milrinone in 24 patients undergoing elective coronary artery bypass graft (CABG). Patients were assigned to the milrinone group (n = 12) and the control group (n = 12). Before separation from CPB, milrinone was administered as a loading dose of 50 micrograms.kg-1 into the reservoir of CPB at rectal temperature 33.5 degrees C and simultaneously a continuous infusion of 0.5 microgram.kg-1.min-1 was started. In addition, dopamine and nitroglycerine were administered in both groups. Hemodynamic measurements were performed before CPB, just after the weaning from CPB, 15, 30, 60 minutes after the weaning from CPB. Cardiac index increased significantly (P < 0.01) in the milrinone group as compared with the control group. Systemic vascular resistance index and mean arterial pressure decreased significantly (P < 0.0001, P < 0.05, respectively) in the milrinone group as compared with the control group. There were no significant differences in heart rate, mean pulmonary arterial pressure, pulmonary artery occlusion pressure, mean right atrial pressure, stroke volume index, and pulmonary vascular resistance index between the two groups. These hemodynamic effects showed that milrinone supported cardiac performance after CPB for CABG.

Adult↗
PubMed1999

[Hemodynamic monitoring in 52 serious burn patients in ten years].

OBJECTIVE: To determine the benefit of hemodynamic monitoring for resuscitation of burn shock. METHODS: A group of 52 burned patients with mean burn area of (69.9 +/- 20.1)% TBSA burn injury (range 31%-100%), and mean III burn area of (60.4 +/- 13.6)% TBSA were included in this study. Swan-Ganz catheters were inserted to monitor hemodynamics including RAP, PAP, PAWP, HR, CO, CI, and SI, etc. after admission at 8, 16, 24, 36, 48, 72, and 96 hours postburn. RESULTS: It was reasonably safe to perform invasive monitoring during early resuscitation. With the guide of hemodynamic monitoring, evidence of global hypovolemia disappeared at 24 hours after burn injury with appropriate resuscitation therapy. CONCLUSION: Invasive hemodynamic monitoring may be necessary to optimize resuscitation of serious burn patients with reasonable safety.

Adolescent↗
PubMed2001

[Central hemodynamic disorders and rheological red blood cell properties in hemorrhagic fever patients with renal syndrome].

The aim of this study was to detect a relationship between hemodynamic disorders in patients with hemorrhagic fever with the renal syndrome (HFRS) and erythrocyte aggregability and erythrocyte membrane ATPase activity. A total of 100 patients with HFRS of different severity were examined. Central hemodynamic parameters were studied: circulating blood volume, minute volume, cardiac index, stroke volume, and total peripheral vascular resistance during preoliguria, oliguria, and polyuria periods. Blood parameters were studied: percentage of minimum and maximum aggregation, disaggregation coefficient, activities of transport adenosine triphosphatases (Na, K, and Ca-activated ATPases and Mg-dependent ATPase). The main hemodynamic parameters were increased (p < 0.05) during early preoliguria and decreased during oliguria; during the polyuria period they again corresponded to the hyperkinetic circulation. The minimum erythrocyte aggregation increased by 110 and 130% in medium-severe and severe HFRS, respectively, the maximum erythrocyte aggregation by 20 and 28%, respectively (p < 0.05). Disaggregation coefficient decreased by 55%. The activities of Na, K(+)-ATPases decreased by 13% during preoliguria period, by 17.5% during oliguria, and by 11.7% during polyuria (p < 0.05) in patients with moderate disease. In severe disease these decreases were 14, 19, and 15%, respectively (p < 0.05). Similar changes were observed in the activities of Ca(++)-ATPase and Mg-dependent ATPase. Hence, the detected hemodynamic changes in patients with medium-severe and severe HFRS correlated with disorders in erythrocyte aggregability and decreased activity of transport ATPases, which can be used for evaluation of the severity of clinical condition and early diagnosis.

Adult↗
PubMed2001

Arterial compliance is an independent factor predicting acute hemodynamic performance of intra-aortic balloon counterpulsation.

Data concerning the effect of arterial compliance (AC) on hemodynamics during intraaortic balloon counterpulsation (IABC) are lacking. This study examines the effect of AC on acute hemodynamics induced by IABC in 15 patients with post-infarction cardiogenic shock. AC was estimated by aortic pulse wave analysis using the reflection time index (RTI). Measurements were obtained once per day during IABC. The % reduction in systolic aortic pressure (ASAP), end-diastolic aortic pressure (AEDAP) and the peak aortic diastolic augmentation (PADA) were used as performance indices of IABC; 107 sets of measurements were obtained. Multivariate analysis indicated an independent association of each IABC performance index with AC (p<0.05). A high AC group (RTI< or =20.6%, n=40) and a low AC group (RTI>20.6%, n=67) were obtained. DeltaSAP deltaEDAP and PADA were significantly higher in the low AC group by almost 75%, 54.6% and 11.3% (p<0.03), while arterial blood pressure did not significantly differ. Arterial compliance is an independent factor affecting hemodynamics during IABC. RTI values higher than 20.6% may predict a better acute hemodynamic response to IABC.

Aged↗
PubMed2001

[Impaired maternal and fetal hemodynamics in the pathogenesis of gestosis].

The study was undertaken to examine the specific features of maternal and fetal hemodynamics in the pathogenesis of gestosis and to develop differential approaches to obstetric policy. For this, a total of 345 pregnant women at risk for gestosis were examined. This condition was prevented using aspirin and trental in 60 women. The findings suggest that hypokinetic central hemodynamics with increased total peripheral vascular resistance and with impaired blood flow in the uterine and spiral arteries are a valid predictor of gestosis. Changes in maternal hemodynamics are revealed just in the late first to early second trimester of gestation. The use of aspirin and trental in patients with hypokinetic central hemodynamics and impaired blood flow in the uterine and spiral arteries reduced the incidence of gestosis by 2.5 times, delayed intrauterine fetal development by 3 times.

Adolescent↗
PubMed1999

[Effects of hypotension induced by isoflurane on hemodynamics and plasma beta 2 microglobulins and creatinine during cerebral aneurysm operation].

OBJECTIVE: To investigate the effects of isoflurane-induced hypotension on the hemodynamics and the changes of plasma beta 2 microglobulins and creatine during cerebral aneurysm operation. METHODS: Thirty-two cerebral anuerysm patients were operated under general anesthesia. Anesthesia was induced with droperidol, fentayl, sodium pentothal and pavolon intravenously. After tracheal intubation, the isoflurane was inhalated to maintain anesthesia. The concentration of isoflurane was elevated to reduce MAP by 30%-40% during dissection and occlusion of tumor and the level maintained for 30-45 min. Hemodynamic values were measured with Swan-Ganz technique. The hemodynamic parameters(CO, CI, SV, SI, SVR, LVSWI, RVSWI, CVP, CPP, RPP and HR) which were measured with Swan-Ganz technique before, during and after isoflurane-induced hypotension were compared. Blood samples were drawn in given time intervals to determine the concentration of plasma beta 2 Microglobulins(beta 2 MG) by radioimmunoassay. Changes in hemodynamics and the plasma beta 2 MG and creatinine (Cr) after deliberate hypotension of isoflurane were recorded at the same time. RESULTS: No significant changes of CO, CI, SV, SI, RVSWI, CVP, HR and ECG tracing were observed during hypotension (P > 0.05). SVR, PVR, LVSWI, Cpp and Rpp were significantly decreased during hypotension (P < 0.05), but the risk of myocardial ischemia and deoxygenation was not increased. No effect was found on the plasma beta 2 MG and Cr during isoflurane-induced hypotension in patients undergoing cerebral aneurysm cling operation. CONCLUSION: Hypotension induced by isoflurane during cerebral aneurysm operation is able to keep a good balance of myocardial oxygen delivery and consumption, and keep a good myocardial function.

Creatinine↗
PubMed2001

Acute and chronic hemodynamic effects of enhanced external counterpulsation in patients with angina pectoris.

BACKGROUND: Enhanced external counterpulsation (EECP) is an effective noninvasive treatment for patients with angina pectoris. However, the hemodynamic effects of EECP are still unknown and have been theorized to simulate the clinical use of the intra-aortic balloon pump, enhancing cardiac output, stroke volume, and retrograde aortic diastolic flow. METHODS: Twelve hemodynamic parameters were measured, using the BioZ System (CardioDynamics International Corporation, San Diego, Calif) after 1 hour (n=22) and after 35 hours (n=16) of EECP treatment compared with baseline. The BioZ System noninvasively measures hemodynamic parameters using the thoracic electrical bioimpedance method. RESULTS: One hour of EECP treatment revealed a significant decrease in cardiac output, stroke volume, contractility, afterload, preload, and myocardial energy production, but systolic time ratios and thoracic fluid content were unchanged. However, after 35 hours of therapy, stroke volume (P < or = 0.05), index of contractility (P < or = 0.05), and thoracic fluid content (P < or = 0.01) were decreased. CONCLUSIONS: The acute reduction in contractility, preload, and concurrent bradycardia may have favorable hemodynamic effects for patients with angina pectoris. Further studies are needed to elucidate the mechanism of EECP therapy and its efficacy for patients with angina pectoris.

Aged↗
PubMed1999

[Staging-syndrome differentiation in treating diabetic foot disorder and its effect on hemodynamic changes of lower extremities with arterial ultrasonic Doppler diagnostic apparatus].

OBJECTIVE: To observe the therapeutic effect of staging-Syndrome Differentiation of TCM in treating the diabetic foot disorder and the corresponding hemodynamic changes in lower extremities. METHODS: Chromatic ultrasonic Doppler diagnostic apparatus (ATL-ULTRAMARK 9 HDI, made in USA) was used to determine the arterial hemodynamic changes and clinical effect on the treatment of diabetic foot disorder in 60 non-insulin dependent diabetes mellitus (NIDDM) patients, among them 30 were treated by staging-Syndrome Differentiation of TCM, and the other 30 as control group treated with 654-2, and the 30 cases of nondiabetic foot disorder as normal control group in comparison. RESULTS: Compared to the normal control, the intravascular diameter, blood flow of both treated groups reduced, maximal and minimal speed of blood flow, and the mean speed were accelerated. Values in dorsal pedis artery had present the most sensitive one. In the comparison between before and after treatment, both treated groups were hemodynamic improvement in the lower extremities' artery, more obviously the dorsal pedis artery, while the comparison between these two groups showed that TCM staging-Syndrome Differentiation had a superior effect on lower extremities' hemodynamics to that of 654-2 group. The comprehensive assessment revealed that the treated groups was also significant different in comparing to that of normal control group (P < 0.05). CONCLUSION: The comprehensive TCM treatment of staging-Syndrome Differentiation as the main therapeutic component was prominently better than that of 654-2 application in the treatment.

Adult↗
PubMed2001

[Early hemodynamic changes in chronic obstructive pulmonary disease with initial respiratory failure].

The chronic hypoxemia seems to play an important role in the pathogenesis of hemodynamic disorders in chronic obstructive pulmonary disease (COPD). The aim of the study was to follow-up the changes in pulmonary hemodynamics in COPD with mild respiratory failure. 78 COPD patients with Ist and IId degree of respiratory failure were investigated. The following investigations were carried out: two--dimensional echocardiography, spirometry, arterial blood gases and acid-base balance. In 18 of COPD patients a right heart catheterization was performed and the following indices were determined: mean pulmonary arterial (PA) pressure, pulmo-capillary resistance, teledyastolic right ventricular volume. The echocardiography showed significantly higher mean PA pressure values, an initial right ventricular dilatation and right ventricular wall hypertrophy. The indices of right heart catheterization were changed, too. The pulmo-capillary resistance was significantly increased. It was the most sensitive early parameter. The mean PA pressure was increased. There was no significant difference between the mean PA pressure determined by echocardiography and by right ventricular catheterization. A relationship between the degree of hypoxemia and the hemodynamic changes was found. The long development of COPD with mild respiratory failure leads to disorders in lung microcirculation and early changes in pulmonary hemodynamics. This process worsens the prognosis of COPD and the early prevention in the complex therapy of the disease is necessary.

Acid-Base Equilibrium↗
PubMed2001

Mechanosensitive endothelial gene expression profiles: scripts for the role of hemodynamics in atherogenesis?

The possibility that hemodynamic forces can act as a "local risk factor" for endothelial dysfunction provides a conceptual framework for the longstanding observation that the earliest lesions of atherosclerosis develop in a nonrandom pattern, the geometries of which correlate with branch points and other regions of altered blood flow. This has led us to hypothesize that hemodynamic forces, in particular wall shear stresses generated by complex patterns of blood flow, can function as both positive and negative stimuli in atherogenesis via effects on endothelial cell gene expression. To understand how endothelial cells in different regions of the arterial tree acquire both functional and dysfunctional phenotypes due to regional hemodynamics, it was important to begin to delineate, in a comprehensive fashion, the mechanoresponsiveness of endothelial cells. To address this fundamental question, we undertook high-throughput transcriptional profiling to assess the global patterns of gene expression in cultured endothelial cells exposed to two defined biomechanical stimuli. Analyses of the transcriptional activity of thousands of genes have revealed unique patterns of gene expression associated with certain types of stimuli. These unique gene expression programs and their associated functional phenotypes constitute the strongest evidence to date that vascular endothelial cells can discriminate among different types of biomechanical stimuli. The results of these studies and the working hypotheses inspired by detailed molecular analyses of biomechanically activated vascular endothelium promise to provide new insights into the role of hemodynamics in the pathogenesis of atherosclerosis.

Arteriosclerosis↗
PubMed2001

Hemodynamics of the Freestyle bioprosthesis in young patients.

The objective of this study was to analyze hemodynamics of the Freestyle stentless bioprosthesis in young patients compared with the older age group. The Freestyle aortic bioprosthesis is a stentless aortic xenograft. Hemodynamics are proven to be good in older patients for a long period. Experience is limited in the younger age group. Therefore the hemodynamics of 71 patients younger than 60 years (14-59 years) were compared with the data of 471 patients older than 60 years (60-86 years) during a follow-up period of 6 years. In the study, 542 consecutive patients with a Freestyle aortic bioprosthesis underwent an echocardiographic and Doppler examination according to a common protocol. Investigations were done within 4 weeks after operation, after 3 to 6 months, and then every year. Mean gradients of the young patients were 8.7 +/- 5.3 mm Hg at discharge and remained between 5.2 +/- 3.9 mm Hg and 11 +/- 5.6 mm Hg during the complete follow-up period. Gradients of the older patients were 8.3 +/- 5.4 mm Hg at discharge and remained between 5.1 +/- 3.7 mm Hg and 6.5 +/- 7.9 mm Hg. Cardiac index during the follow-up period was equal in both groups. Doppler values were evaluated for the Freestyle stentless porcine bioprostheses in the aortic root both for patients younger than 60 years and patients over 60 years of age. Midterm hemodynamic performance is equal in both groups.

Adolescent↗
PubMed2001

Hemodynamic performance of stentless porcine bioprosthesis and mechanical bileaflet prosthesis using dobutamine stress echocardiography.

Currently available aortic valve prostheses have satisfactory hemodynamic performance during rest, but with exercise they possess different responses. The objective was to compare the hemodynamic response of the stentless porcine bioprosthesis (SP) and the mechanical bileaflet prosthesis (MB) at rest and during peak exercise using dobutamine stress echocardiography (DSE). DSE was used to evaluate the effective orifice area index (EOAI), peak and mean pressure gradients at rest and during maximum stress in 15 patients with SP (group T, mean age, 30.9 year) and another 15 patients with MB (group M, mean age, 28.6 year). The increment in pressure gradient (mean/peak) was significantly less in patients with SP than those with MB (P <.01). The EOAI did not change with exercise. At rest, both valve substitutes have satisfactory hemodynamics, but during exercise the stentless porcine bioprosthesis has better hemodynamics because it is less obstructive that justifies its use in young population.

Adult↗
PubMed2001

Eight-year hemodynamic follow-up after aortic valve replacement with the Toronto SPV stentless aortic valve.

The hemodynamic performance of stentless aortic bioprostheses has been well described during the first few months after surgery. The purpose of the present study was to describe the hemodynamic performance of the Toronto SPV valve (St. Jude Medical, Inc, St. Paul, MN) in a multicenter trial through 8 years. The long-term study of the Toronto SPV valve includes 447 consecutive patients from 6 investigative centers. Echocardiographic follow-up was performed at specified intervals, with quantitative analysis performed at a centralized core laboratory. Mean transvalvular gradient decreased significantly between discharge and 6 months, between 6 months and 1 year, and between 1 year and 2 years after surgery, without further significant change. The effective orifice area increased significantly early after surgery and continued to increase through 6-year follow-up. The left ventricular (LV) stroke volume increased progressively from discharge through 6-year follow-up. The LV mass index decreased significantly from discharge through 3 years after surgery and stabilized through 5 years. There was a gradual increase in LV outflow tract diameter between 1 year and 6 years after surgery. The prevalence of any aortic regurgitation (AR) (including trivial) and > or = mild AR increased significantly between discharge and 6-year to 8-year follow-up. However, the prevalence of > or = moderate AR remained very low at 6 years (2.6%) and 8 years (4.5%) after surgery. In conclusion, the Toronto SPV stentless tissue aortic valve is associated with excellent hemodynamics early after surgery and through 8 years after surgery. LV mass decreases early, and returns to within the range of normal by 1 year after surgery. There is evidence of continued LV mass regression involving the LV outflow tract, potentially contributing to a small but significant late improvement in hemodynamics. The prevalence of significant AR remains low through 8 years.

Adult↗