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PubMed1988

[Thyroid hormone metabolism in nonthyroidal illness. I. Changes in thyroid hormone metabolism in dogs with experimental myocardial infarction and effect of thyroid hormone administration on their hemodynamics].

To asses the changes in thyroid hormone metabolism after the onset of acute myocardial infarction (AMI), serum T4 and T3 levels were serially measured for 24 hours after the coronary artery ligation in dogs. The effect of thyroid hormone administration on hemodynamics in these dogs were also studied to clarify the possible usefulness of thyroid hormone therapy in nonthyroidal illness (NTI). Dogs were anesthetized with ketamine using "Micro-Mini" drip administration. Coronary artery ligation was performed in 8 dogs (MI group) Open chest operation was performed in 8 dogs, but their coronary arteries were not ligated and were used as control (cont. group). Blood samples were drawn before and 1, 3, 6, 12, 18 and 24 hours after coronary artery ligation, and serum levels of T4 and T3 were measured using the TDX T4 system and a commercial RIA kit, respectively. Various hemodynamic parameters (heat rate, mean blood pressure, max dp/dt, left ventricular end-diastolic pressure, cardiac output) were measured at the same time mentioned above. All the hemodynamic parameters remained within normal range for 24 hours in the control group. Serum T4 and T3 levels, however, showed slight, but significant decreases due to general anesthesia and open chest operation in the control group. On the other hand, hemodynamic parameters were maintained in the normal ranges only for 12 hours, and gradually deteriorated in the MI group. Moreover, it was remarkable that both T4 and T3 levels were decreased immediately after the ligation in this group, T4 being less than 0.1 micrograms/dl and T3 less than 10 ng/dl. They continued to show the low values thereafter. When T4 (30 micrograms/24 hours), and T3(7, 14 or 21 micrograms/24 hours) were continuously infused intravenously for 24 hours after the coronary artery ligation in 10 dogs, serum T4 levels were maintained in the normal range of the dog (1.5-3.6 micrograms/dl) and the serum T3 levels were increased to the low normal range. However, there were no significant differences in hemodynamic indices between the thyroid hormone treated groups and the non-treated group. These data show that T4 and T3 concentrations decrease prior to the deterioration of cardiac function. Moreover, the present findings also suggest that administration of thyroid hormone has no benefit in patients with NTI associated with low T4 and T3 levels.

Animals↗
PubMed1994

Effects of microsphere suspension agents on systemic hemodynamics in rats. Comparison of nonradioactive colored and radioactive microspheres.

The systemic hemodynamic effects of different microsphere suspension agents were evaluated in 22 Sprague-Dawley male rats. Rats were divided into three groups, and three different solutions (distilled water; n = 7, 10% dextran; n = 8, and 70% glucose; n = 7) were injected through the left atrium respectively. 0.2 ml of each solution was injected repeatedly until significant hemodynamic changes developed. During four sequential injections, distilled water had no significant effects on cardiac output, mean arterial pressure, and heart rate. However, the 10% dextran (mol wt 70,000) solution produced significant decreases in both cardiac output and mean arterial blood pressure during and after the third injection. The 70% glucose solution also decreased, cardiac output significantly during the third injection. Although microspheres itself must cause some hemodynamic changes, our results indicated that the hemodynamic disturbances observed during a large dose injection of microspheres might have been at least in part due to the use of high-density suspending solutions. The doses of radioactive microsphere solution in many previous rat studies were usually less than 0.6 ml. However, in the case of large dose injection of microspheres, these results indicate that the suspending solutions can affect hemodynamic parameters in various ways.

Animals↗
PubMed1992

Influences of ventricular pacing on hemodynamics, myocardial metabolism, and cardiac work efficiency: potential risks of rate-responsive ventricular pacing.

The influences of ventricular pacing at a rate of 70 beats/min (bpm) on the systemic and coronary hemodynamics, myocardial metabolism, and cardiac work efficiency were evaluated in five patients with bradycardia. The results were compared to those obtained in six normal subjects at rest. In order to elucidate the effects of a relatively high rate of ventricular pacing, cardiovascular and metabolic variables were also obtained at 120 bpm in the normal subjects. It was observed that the patients eventually benefited from ventricular pacing at a rate of 70 bpm and improved in systemic hemodynamics. Although coronary hemodynamics and myocardial metabolism were accelerated, the cardiac work efficiency was not improved. A pacing rate of 120 bpm in the normal subjects did not appear to accelerate systemic hemodynamics, but adverse accelerations of coronary hemodynamics and myocardial metabolism were observed, and the cardiac work efficiency was remarkably reduced as a result. Our observations indicated that the coronary reserve capacity was very important for ventricular pacing, and suggested that an undue increment of the pacing rate not only might be meaningless but also might induce ischemic angina. Therefore, we should be cautious in using a rate-responsive pacing mode, particularly in determination of the upper limit of pacing rates, although many benefits with this pacing mode have recently been advocated.

Adult↗
PubMed1994

The effects of chronic endoscopic variceal sclerotherapy on systemic and splanchnic hemodynamics in patients with cirrhosis.

The aim of this study was to determine whether endoscopic variceal sclerotherapy affects systemic or splanchnic hemodynamics. We measured hemodynamic parameters before and after the first course of sclerotherapy in 35 patients with cirrhosis. Following sclerotherapy, there was a significant decrease in cardiac index and a significant increase in systemic vascular resistance. Changes in hepatic venous pressure gradient varied from patient to patient with no statistically significant change in the group overall. However, all 20 patients with a decline in the hepatic venous pressure gradient had a concomitant decrease in cardiac index and/or a large extravariceal shunt. The multivariate analysis disclosed that the decrease in cardiac index was a statistically significant contributor for the decline in hepatic venous pressure gradient. We conclude that the obliteration of esophageal varices by sclerotherapy significantly reverses the hyperdynamic circulatory state in patients with cirrhosis. Spontaneous changes in systemic hemodynamics and the interaction with hepatic hemodynamics must be taken into account when evaluating hepatic hemodynamics in patients undergoing variceal sclerotherapy.

Endoscopy↗
PubMed2006

Cardiopulmonary hemodynamic changes during acute subdural hematoma evacuation.

The aim of this study was to clarify the mechanism of hemodynamic changes leading to intraoperative hypotension during evacuation of acute subdural hematoma. To our knowledge, little data is available about the mechanism of hemodynamic changes during surgical interventions to decrease intracranial pressure after severe head injury. The influence of preoperative hypotension on intraoperative hypotension was examined. Hemodynamic studies (pulmonary artery catheterization) were carried out in 15 patients before and after acute subdural hematoma evacuation. All patients were assessed for hemodynamic parameters, evacuated hematoma volume, and intracranial pressure measurements. Comparison between just before and after evacuation of the hematoma showed that the mean arterial pressure, pulmonary arterial pressure, systemic vascular resistance, pulmonary vascular resistance, central venous pressure, and pulmonary capillary wedge pressure all decreased after hematoma evacuation. However, the cardiac index was unchanged after hematoma evacuation. Mean arterial blood pressure is dependent on the cardiac index and vascular resistance, so the decrease in arterial blood pressure during hematoma evacuation was the result of a decline in vascular resistance. The influence of preoperative blood pressure on intraoperative hemodynamic changes was analyzed by dividing the patients into two groups, the preoperative hypotension group and preoperative nonhypotension group. The decrease in mean arterial blood pressure was more marked in the preoperative hypotension group than in the preoperative nonhypotension group. Intraoperative hypotension during evacuation of acute subdural hematoma is caused by a decrease in vascular resistance. Preoperative hypotension is a also risk factor for intraoperative hypotension.

Adult↗
PubMedDate not supplied

[Sensitivity of hemodynamic parameters determined with a conventional duplex scanner in the evaluation of severe extracranial carotid disease].

Progression of extracranial carotid disease is considered to be significant independent predictor in the evaluation of individual cerebrovascular prognosis. Doppler ultrasonography is a useful screening method in the diagnosis and evaluation of extracranial carotid disease. The aim of this study was to establish the most sensitive hemodynamic parameter of Doppler-ultrasonographic spectral analysis in clinical evaluation of extracranial carotid disease. Investigation included 90 patients (of both sexes) in hospital and outpatient clinic care. Spectral analysis (M-scanning technique) was used for the evaluation of hemodynamic status of carotid sinus, including the following parameters: Pourcelot (A-D/A), Gosling (A/B), and Mol (A/D) resistance parameters. After statistical processing the results of the research affirmed hemodynamic parameters' values and correlation between Pourcelot hemodynamic parameter and the degree of carotid stenosis rho = 0.59 for all patients, and rho = 0.58 for patients with pathological values. Correlation between Mol parameter and the degree of carotid stenosis was rho = 0.50 for all patients, and rho = 0.57 for patients with pathological values. Gosling parameter was not significantly different in mean value and was present in all three groups. Functional relationship between the degree of carotid stenosis and each of hemodynamic parameters was established. It was concluded that Pourcelot and Mol parameters were significant indicators of asimptomatic carotid disease, but Pourcelot parameter was considered as a more sensitive indicator in the evaluation of extracranial carotid disease.

Adult↗
PubMed1996

Central and peripheral hemodynamics in severe preeclampsia.

BACKGROUND: Doppler velocimetry, a new tool for measuring blood flow, vascular resistance, and central hemodynamics can be applied to monitor those patients at risk and provide therapeutic concepts for preeclampsia. This study was designed to use a Doppler velocimetry study to correlate the relationship between central hemodynamics, uteroplacental circulation, and the perinatal outcome in severe preeclampsia. METHODS: Thirty-one patients with severe preeclampsia, not superimposed with any medical disorder and not on antihypertensive treatment prior to admission, were enrolled in this study. On admission, laboratory determination of the maternal blood chemistry and hematogram, together with a Doppler ultrasound study of the maternal hemodynamics, and umbilical and uterine arteries, were performed. Antihypertensive agents including hydralazine, atenolol, and labetolol were given according to the state of the maternal central hemodynamics. Data were collected on the general status of the patients, the results of the Doppler ultrasound study, and the perinatal outcome. RESULTS: Patients were divided into three groups based on the systemic vascular resistance. The left ventricular function and cardiac index declined with increase in vascular resistance. The high-resistance group had a significantly high incidence of infants small for gestational age. Poor fetal growth in the high-resistance group could be attributed to the summation of underperfusion due to decreased uteroplacental blood flow and was frequently associated with maternal hemoconcentration. CONCLUSIONS: Although global vasospasm has been considered to be the basic pathophysiology of preeclampsia, the central hemodynamics varies between, and even in the same, patients. Regional vasospasm in the uteroplacental circulation occurs earlier than in the systemic circulation as a whole. A high cardiac-output in low systemic-vascular-resistance might compensate in those pregnancies with high uterine artery resistance to maintain adequate uteroplacental perfusion.

Adult↗
PubMed1987

Acute and subacute hemodynamic effects of enalaprilat, milrinone and combination therapy in rats with chronic left ventricular dysfunction.

A model of congestive heart failure (CHF) was produced in rats approximately 76 days following surgical occlusion of the left coronary artery. In rats with healed myocardial infarction (MI size = 45% LV), hemodynamic variables were predictably elevated (LVEDP greater than 20 mm Hg) or depressed LV dP/dtmax (5200 mm Hg/sec). The hemodynamic response (MAP, HR, LVEDP, and dP/dtmax) to intravenous infusion of Mil (54 to 347 micrograms/kg) was measured on two occasions, separated by a 7-12 day period of oral treatment (2 mg/kg/day). Enalaprilat was tested in a similar design with the infusion phase (70 micrograms/kg, total dose) separated by oral enalapril (Enal), 1 mg/kg/day. The hemodynamic response to Mil was also examined in rats treated with the ACE inhibitor. At low doses, Mil modestly elevated HR (+17 beats/min) and dose-dependently increased (P less than 0.05) LV contractility by approximately 25%. Higher doses of Mil reduced preload (LVEDP) and afterload (MAP). Oral Mil produced little hemodynamic improvement except modest elevation (+9%) in LV contractility. There was no evidence of tachyphylaxis to i.v. Mil. In contrast, enalaprilat reduced MAP and preload without altering HR or contractility, effects observed after oral treatment. In the presence of the ACE inhibitor, Mil's hemodynamic actions were not enhanced. These experiments demonstrate that ACE inhibition improves ventricular performance by reducing preload and afterload. In this model, Mil improves performance by a direct inotropic mechanism as well as a reduction in afterload.

Animals↗
PubMed1997

Hemodynamic and metabolic disturbances in patients with intracranial dural arteriovenous fistulas: positron emission tomography evaluation before and after treatment.

In patients with intracranial dural arteriovenous fistulas (AVFs), clinical symptoms and angiographic findings vary. The relevance of disturbed venous drainage to clinical symptoms and prognosis has been recognized. However, the roles of cerebral hemodynamics and metabolism, which are impaired by shunt flow or disturbed venous drainage, have not been fully evaluated. The authors studied the cerebral hemodynamic and metabolic status in 10 patients with intracranial dural AVFs using positron emission tomography (PET) scanning. Ten patients with dural AVFs underwent a PET study before treatment. The regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rOEF), regional cerebral metabolic rate of oxygen (rCMRO2), and regional cerebral blood volume (rCBV) were measured using the 15O-labeled gas inhalation steady-state method The PET parameters that were obtained were analyzed and compared with the patients' neurological and angiographic findings. In six of the 10 patients, a PET study was also performed after treatment. Before treatments, all four patients with cerebral symptoms showed a severe reduction in rCBF and a mild elevation in the rOEF. The areas showing reduced rCBF corresponded with areas in which retrograde venous drainage into the cortical veins and delayed parenchymal circulation were seen on angiograms. In another two patients with occlusion of the affected sinus and/or retrograde drainage into the cortical veins, mild abnormalities were demonstrated in rCBF mapping. In the remaining four patients, all PET parameters except rCBV were within normal limits and venous flow was not impaired on the angiograms. In four patients who underwent surgical excision or transvenous embolization of the affected sinus, the cerebral hemodynamics and metabolism were improved, as were the clinical symptoms. In two patients who underwent transarterial embolization of the feeding vessels only or craniotomy, no hemodynamic improvement was achieved. Our results indicate that hemodynamic insufficiency detected by the PET study corresponded well with cerebral symptoms and angiographic findings of retrograde venous drainage into the cortical veins and delayed parenchymal circulation, but not with sinus occlusion or arterial blood supply. Eradication or prevention of retrograde venous drainage from the affected sinus into the cortical veins should be a treatment goal in patients with dural AVFs.

Aged↗
PubMed2003

Characterization of the pulmonary circulation according to hemodynamic changes by computed tomography.

Increased or decreased pulmonary blood flow (PBF) and an increased pulmonary vascular resistance (PVR), represent common and important change in pulmonary hemodynamics. In this study, we constructed 3 hemodynamic models in 5 dogs, that is, an increased and a decreased PBF model, and an increased PVR model. A CT perfusion scan was performed in each hemodynamic model. Perfusion parameters including blood flow (BF), blood volume (BV), mean transit time (MTT), and maximal slope (MS) were calculated automatically by specialized software and analyzed for changes according to hemodynamic status. In terms of the normal state, blood flow was affected by gravity and dependent area showed higher BF and BV and lower MS and MTT than the non-dependent area. The decreased PBF model showed a significant increase in BF and MS (p=0.046, 0.005) but no significant change in BV (p > 0.05), and a slight elongation of MTT (p > 0.05) versus the normal state. The increased PBF model showed a slightly increased BV and a slightly decreased MTT (p > 0.05). The increased PVR model showed significant reduction in BF, BV, and MS (p < 0.000, 0.007, 0.000) and a slight increase in MTT, but without statistical significance (p > 0.05). However, it was noticeable that the distribution of MTT with respect to gravity in the normal lung was completely reversed in the increased PVR model. In conclusion, based on our understanding of perfusion characteristic in normal state, abnormal regional hemodynamic changes in the lung can be detected and evaluated. Predicting changes in pulmonary vascular resistance should be possible by a thorough analysis of CT perfusion parameters.

Animals↗
PubMed1990

Hemodynamic clinical profiles.

Hemodynamic profiling provides valuable information about cardiac output and its determinants: preload, afterload, and contractility. The direct and derived parameters of these determinants are used by expert critical care nurses in collaboration with medical directives for intervention to enhance clinical assessment, decisionmaking, and evaluation. This article reviews the basic and advanced aspects of hemodynamic profiling. The parameters that must be included in a complete hemodynamic profile are discussed with emphasis on the importance of index values. An algorithm is included as a guideline for use of the hemodynamic profile. A variety of clinical examples are discussed to illustrate the importance of hemodynamic profiling as an adjunct to expert critical care nursing practice.

Cardiovascular Diseases↗
PubMed1995

Role of transesophageal echocardiography in hemodynamically unstable patients.

OBJECTIVE: To evaluate the clinical impact of transesophageal echocardiography on subsequent management and outcome in hemodynamically unstable patients with suspected cardiovascular pathologic conditions. DESIGN: We reviewed data on patients with hemodynamic instability (hypotension, shock, or pulmonary edema) who underwent transesophageal echocardiography between December 1987 and May 1994. MATERIAL AND METHODS: A total of 127 patients (70 male and 57 female patients with a mean age of 68 years) underwent transesophageal echocardiography at our institution as part of the diagnostic procedures used to evaluate unstable hemodynamics. RESULTS: No clinically significant complication was encountered during the procedure; transesophageal echocardiographic imaging was inadequate in three patients (2%). Of the 124 patients with adequate images, transesophageal echocardiography disclosed a severe cardiovascular abnormality responsible for the unstable hemodynamics in 65 patients (52%), and 26 patients (21%) underwent urgent pericardiocentesis or a cardiac surgical procedure, primarily based on transesophageal echocardiographic findings. CONCLUSION: Transesophageal echocardiography can be safely performed in hemodynamically unstable patients, it produces a high diagnostic yield, and it provides important information for prompt therapeutic decision making. Therefore, we recommend transesophageal echocardiography as one of the initial diagnostic procedures in critically ill patients suspected of having an underlying cardiovascular disorder.

Aged↗
PubMed1985

Hemodynamic response to oxygen therapy in chronic obstructive pulmonary disease.

At six centers, 203 patients with stabilized hypoxemic chronic obstructive pulmonary disease were evaluated hemodynamically during a continuous or 12-hour oxygen therapy program. Neither oxygen therapy program resulted in correction or near-correction of the baseline hemodynamic abnormalities. The continuous oxygen therapy group did show improvement in pulmonary vascular resistance, pulmonary arterial pressure, and stroke volume index. The improvement in pulmonary vascular resistance was associated with improved cardiac function, as evidenced by an increase in baseline and exercise stroke volume index. The nocturnal oxygen therapy group showed stable hemodynamic variables. For both groups, changes in mean pulmonary artery pressure during the first 6 months were associated with subsequent survival after adjustment for association with the baseline mean pulmonary artery pressure. Continuous oxygen therapy can improve the hemodynamic abnormalities of patients with hypoxic chronic obstructive pulmonary disease. The hemodynamic response to this treatment is predictive of survival.

Aged↗
PubMed1984

Hemodynamic monitoring in respiratory care.

Continuous, invasive hemodynamic monitoring of patients in respiratory failure is an important aspect of total respiratory care. Understanding both the technical and physiological principles underlying hemodynamic monitoring is therefore important for respiratory care practitioners. This review is designed to meet this need by (1) addressing the technical aspects of hemodynamic monitoring (catheters, transducers, and monitors), (2) discussing the determinants of commonly measured hemodynamic variables (intravascular pressures and cardiac output), and (3) offering an orderly approach to hemodynamic data that allows for rapid determination of the patient's physiologic state and appropriate diagnostic possibilities. These principles are illustrated by five examples.

Hemodynamics↗
PubMed1998

Dynamic study of nitric oxide and endothelin-1 during endotoxin shock and effects of their antagonists on hemodynamics.

OBJECTIVE: To examine the relationship between the profound hypotension in endotoxic shock and the dynamic changes of nitric oxide (NO) and endothelin-1 (ET-1), so as to figure out which of the NO or ET-1 was more involved in the pathogenesis of endotoxic shock. And to investigate whether an offset of their opposite vasoactive effects would occur during endotoxic shock. METHODS: 24 rabbits were anesthetized and instrumented for recording hemodynamics. Endotoxin (E. coli 026: B6, 600 micrograms/kg) was bolus injected intravenously and the animals were randomly divided into four groups. Group I was control without any more intervention, and Group II, III, IV received bolus injections of L-NMA (10 mg/kg), phosphoramidon (2 mg/kg) or dexamethasone (2 mg/kg) respectively at 30 min post-endotoxin. Plasma NO3-, ET-1 and hemodynamics were measured at regular intervals. Their relationships were compared and analysed. RESULTS: Plasma ET-1 achieved its peak level at 60 min post-endotoxin, and then waned. Plasma NO3- started rising at 120 min post-endotoxin, then progressive increase continued till the last measurement at 180 min post-endotoxin. The decrease of blood pressure was significant at about 120 min post-endotoxin and further went down until death. The changes of hemodynamics and NO showed a quite close temporal correspondence between the increase of NO and the decrease of blood pressure. L-NMA and phosphoramidon obviously reduced the plasma levels of NO and ET-1 to below their respective baseline levels, and showed transient effect of increase on blood pressure. Soon afterwards, however, the status of hemodynamics was aggravated. Dexamethasone just inhibited the excessive increase of NO and ET-1 during endotoxic shock without interfering their baseline levels and showed most beneficial effects on hemodynamics. CONCLUSIONS: Both NO and ET-1 increase during endotoxic shock, but only the increase of NO has a close temporal correspondence with the decrease of blood pressure. It suggests a more important role of NO in pathogenesis of endotoxic shock. The increase of NO and ET-1 is different in time-process, which indicates that an offset of their opposite vasoactive effects would not occur. Intreference against the increase of NO and ET-1 during endotoxic shock is most beneficial when their baseline levels are maintained.

Animals↗
PubMed1999

Negative chronotropic effects of fentanyl attenuate beneficial effects of dobutamine on oxygen metabolism: hemodynamic and pharmacokinetic interactions.

Opioids are well known to cause cardiovascular depression. The aim of the present investigation was to determine whether an interaction of opioid derivatives with catecholamines might be involved in these hemodynamic alterations. Six comatose patients were enrolled into a prospective, nonrandomized pilot trial. All patients first received a continuous i.v. infusion of dobutamine (10 microgram. kg-1. min-1) paralleled by continuous administration of midazolam (0.4 mg. kg-1. h-1); thereafter, fentanyl was added i.v. (4 microgram. kg-1. h-1). Hemodynamic parameters as well as dobutamine and endogenous catecholamines plasma levels were determined. The mean arterial blood pressure did not change significantly during the whole study period. The continuous administration of dobutamine (steady-state plasma concentrations: 217 +/- 118 ng. ml-1) increased the beta1-adrenergic receptor-mediated hemodynamic parameters such as heart rate, stroke volume index, cardiac index, and oxygen delivery index (p <.05). The concomitant administration of fentanyl decreased the heart rate-dependent hemodynamic parameters (p <.05), suggesting that fentanyl antagonizes the chronotropic effects of dobutamine. In parallel, dobutamine plasma levels increased significantly (275 +/- 165 ng. ml-1; p <.05). Noteworthy, after administration of fentanyl, oxygen delivery and consumption index returned to baseline values. Radioligand binding experiments on rat cardiac ventricular microsomes ruled out a direct interaction of fentanyl with beta-adrenergic receptors and, more importantly, a fentanyl-induced inhibition of beta-adrenergic receptor G protein coupling. Our observations suggest that fentanyl inhibits the frequency-related hemodynamic changes induced by dobutamine. The underlying mechanism is independent of beta-adrenergic receptors, but is powerful enough to abolish the salutary effect of dobutamine on oxygen delivery and consumption.

Aged↗
PubMed2000

[Degree of hemodynamic disturbance at the hyperacute phase of stroke: predictive value of 3D-TOF angiography and the T2 fast-FLAIR sequence].

GOAL: To define during the hyperacute phase of stroke the value of 3D-TOF MR angiography (MRA) and T2 fast-FLAIR sequence for predicting the volume of tissue presenting a hemodynamic disturbance. MATERIAL: and method: Thirty-five cases of hyperacute stroke located in following territories: middle cerebral artery (MCA) (n=29), anterior choroidal artery (AChoA) (n=5) and watershed (n=1) were retrospectively reviewed. The vascular abnormalities defined on MRA (vessel stenosis or occlusion) or FLAIR sequence (vessel hyperintensity) were classified into 3 groups: normal (I), distal abnormalities (II), abnormalities of the entire arterial territory (III). These results were compared with the volume of tissue showing a prolonged mean transit time (MTT) determined on relative MTT maps calculated from bolus tracking MR perfusion images. RESULTS: The abnormal volume measured on the MTT map was significantly correlated to the results of the MRA and FLAIR sequence. In the 12 cases of group III defined on the MRA (abnormality from M1), the volume of hemodynamic disturbance was always higher than 100 ml. For the MCA territory, it was not possible to predict the presence of a hemodynamic disturbance in any of the 3 groups defined on the FLAIR sequence and in the groups I and II defined on the MRA. For the AChoA territory, a hemodynamic disturbance was never observed in groups I and II defined either on MRA or FLAIR sequence. CONCLUSION: When there was no flow within the M1 segment on the MRA, there was always a hemodynamic disturbance larger than 100 ml on the MTT map. In the case of AChoA ischemic lesion, when no vascular abnormality was observed on the MRA or FLAIR images, the MTT map was always normal.

Acute Disease↗
PubMed2000

Clinical and hemodynamic performance of the Toronto SPV bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: By providing a superior hemodynamic profile, the stentless valve design allows ventricular remodeling and may improve patient survival after aortic valve replacement (AVR). Compared with stent-mounted prostheses, implantation is more complex and requires a longer ischemic time; this may adversely affect surgical risk, especially if patients are elderly or require a concomitant procedure. The mid-term clinical and hemodynamic performance of the Toronto SPV bioprosthesis in a predominantly elderly patient group was analyzed. METHODS: A total of 123 patients (median age 72 years) underwent AVR with the Toronto SPV. Concomitant procedures (mainly coronary artery bypass grafting, CABG), were performed in 60 patients (49%). Clinical details were recorded, with 100% follow up (total 317 patient-years). Hemodynamic evaluation, by serial echocardiography, was performed at four and 18 months after implantation. RESULTS: The early mortality rate was low (0.8%). Mean (+/- SD) actuarial survival at 53 months was 78 +/- 5.9%, with most patients (91%) in NYHA classes I and II. Freedom from valve-related complications were: endocarditis 93.8 +/- 2.3%, thromboembolism 90.3 +/- 3.7% and bleeding 95.8 +/- 1.8%; there were no structural failures. The valve hemodynamic profile was excellent for all sizes: peak gradient 8.8 +/- 4.3 mmHg, effective orifice area 1.9 +/- 0.54 cm2 with significant improvement in left ventricular fractional shortening. CONCLUSION: In this patient population the Toronto SPV was a suitable choice. Advanced age, a requirement for concomitant procedures and increased ischemic times did not adversely affect surgical risk. AVR with the Toronto SPV provided an excellent hemodynamic profile, and improved both left ventricular function and NYHA functional class.

Adult↗