Color Doppler imaging and plasma levels of endothelin-1 in low-tension glaucoma

Endothelin-1 (ET-1) is a potent vasoconstrictor peptide produced by vascular endothelin cells There are reports in the literature that ET-1 plasma levels are raised in low tension glaucoma (LTG). ET-1 plasma concentration and Color Doppler Imaging (CDI) evaluation in ophthalmic and posterior ciliary arteries were measured in 15 LTG patients and in 15 healthy subjects. The blood flow index recorded for the ophthalmic artery in normal subjects was a PSV of 36.646 +/- 6.611 cm/sec with RI of 0.717 +/- 0.019 while in the LTG patients it was 32.961 +/- 3.045 cm/sec (p < 0.003) with RI of 0.789 +/- 0.018 (p < 0.001). For the posterior ciliary arteries in the same two groups, we obtained a PSV of 13.878 +/- 4.149 cm/sec vs 8.720 +/- 1.645 cm/sec (p < 0.001) and an RI of 0.679 +/- 0.039 vs 0.722 +/- 0.024 (p < 0.001). The plasma ET-1 level in normal subjects was 1.720 +/- 0.174 pg while in LTG patients it was 2.947 +/- 0.217 pg (p < 0.001). On the basis of our experience, we think that GON and the visual field damage found in LTG can be attributed to an alteration in the endothelial self-regulating sections and consequent vascular insufficiency, particularly pronounced in the posterior ciliary arteries which, since it is these that provide the blood supply to the optic nerve head, leads to irreversible functional damage.     

Blood-flow velocities in the extraocular vessels in normal volunteers

PURPOSE: To determine normal values of blood-flow velocities in extraocular vessels. METHODS: In one eye each in 189 healthy adult volunteers, blood-flow velocities in the ophthalmic artery (OA), central retinal artery (CRA), central retinal vein (CRV), short lateral posterior ciliary artery (LPCA), and short medial posterior ciliary artery (MPCA) were measured by color Doppler imaging. In the arteries, peak systolic velocity (PSV), end diastolic velocity (EDV), and resistivity index (RI) were calculated. In the CRV, maximal and minimal blood-flow velocities were measured. Influence of age, gender, blood pressure, and heart rate on blood-flow velocities and the resistivity index were analyzed. RESULTS: Mean outcomes +/- S.D. cm/sec were as follows: in the OA, PSV was 39.2 +/- 5.3, EDV was 9.1 +/- 2.5, and RI was 0.77 +/- 0.05. In the CRA, PSV was 11.0 +/- 1.8, EDV was 3.3 +/- 0.9, and RI was 0.71 +/- 0.05. In the short LPCA, PSV was 11.2 +/- 1.7, EDV was 3.7 +/- 1.0, and RI was 0.68 +/- 0.06. In the short MPCA, PSV was 11.2 +/- 11.7, EDV was 3.6 +/- 0.9, and RI was 0.68 +/- 0.05. In the CRV, mean maximal velocity was 4.5 +/- 0.9, and mean minimal velocity was 3.3 +/- 0.7. Age, gender, systolic blood pressure, diastolic blood pressure, and heart rate had no consistent statistically significant influence on the measured and calculated variables. CONCLUSION: Normal values for blood-flow velocities in the extraocular vessels serve as a basis in deciding whether a measured value of a patient is normal or abnormal.     

Reproducibility of color Doppler imaging in orbital vessels

The purpose of this study was to evaluate the short-term reproducibility, the long-term reproducibility, and the reproducibility of the measurements made between two different examiners of blood-flow velocity in extraocular vessels using color Doppler imaging (CDI). In a group of 10 healthy volunteers, measurements of the peak-systolic velocity (PSV), end-diastolic velocity (EDV), and resistivity index (RI) in the ophthalmic artery and the central retinal artery as well as one lateral and one medial short posterior ciliary artery were performed. The best intraindividual reproducibility, expressed as the relative error, was found for the PSV and RI measured in the ophthalmic artery (OA; PSV 5.9%, RI 3.1%) and the central retinal artery (CRA; PSV 7.7%, RI 4.7%). The PSV and RI determined in the posterior ciliary arteries were less reproducible but as much so as the EDV measured in the OA (11.8%) and CRA (19.9%). No systematic trend could be found between the first and second measurements. However, the long-term fluctuation was considerable high. Measurements of PSVs showed good concurrence between the two observers in all four vessels measured. The EDVs and RIs differed statistically significantly between the two observers. This difference was most pronounced in the posterior ciliary arteries.     

A dehydroalanyl residue can capture the 5''-deoxyadenosyl radical generated from S-adenosylmethionine by pyruvate formate-lyase-activating enzyme

OBJECTIVE: To analyze the effects of carotid endarterectomy on the retrobulbar circulation of patients with severe occlusive carotid artery disease (OCAD) by means of color Doppler imaging (CDI). DESIGN: Prospective. PARTICIPANTS: A total of 17 consecutive patients with severe OCAD and neurologic symptoms (with a history of transitory ischemic attack or cerebral vascular accident) participated. INTERVENTION: All 17 patients underwent carotid endarterectomy. The CDI of both orbits was performed by one masked investigator before surgery and at 1 week and 1 month after surgery. MAIN OUTCOME MEASURES: Peak systolic velocity, end diastolic velocity, and resistive index of the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. The authors compared the hemodynamic parameters at all intervals. RESULTS: Peak systolic and end diastolic velocities in the ophthalmic, central retinal, and temporal short posterior ciliary arteries increased significantly 1 week and 1 month after carotid endarterectomy (P < 0.05). After surgery, the resistive indices in the central retinal and temporal short posterior ciliary arteries decreased significantly at both intervals (P < 0.05). The six patients who had reversed ophthalmic artery flow before surgery showed forward ophthalmic artery flow after carotid endarterectomy. The contralateral orbits showed no significant hemodynamic change after endarterectomy (P < 0.05). CONCLUSIONS: Hemodynamic changes in patients with severe OCAD undergoing carotid endarterectomy suggest improvement in the ipsilateral retrobulbar blood flow.     

Reversibility of changes in left and right ventricular geometry and hemodynamics in pulmonary hypertension. Echocardiographic characteristics before and after pulmonary thromboendarterectomy

Pulmonary thromboendarterectomy (PTE) leads to an acute decrease of right ventricular (RV) afterload in patients with chronic thromboembolic pulmonary hypertension. We investigated the changes in right and left ventricular (LV) geometry and hemodynamics by means of transthoracic echocardiography. The prospective study was performed in 14 patients (8 female, 6 male; age 55 +/- 20 years) before and 18 +/- 12 days after PTE. Total pulmonary vascular resistance and systolic pulmonary artery pressure were significantly decreased (PVR: preoperative 986 +/- 318, postoperative 323 +/- 280 dyn x s/cm5, p < 0.05; PAP preoperative 71 +/- 40, postoperative 41 +/- 40 mm Hg + right atrial pressure, p < 0.05). End diastolic and end systolic RV area decreased from 33 +/- 12 to 23 +/- 8 cm2, respectively, from 26 +/- 10 to 16 +/- 6 cm2, p < 0.05. There was an increase in systolic RV fractional area change from 20 +/- 12 to 30 +/- 16%, p < 0.05. RV systolic pressure rise remained unchanged (516 +/- 166 vs. 556 +/- 128 mm Hg/sec). LV ejection fraction remained within normal ranges (64 +/- 16 vs. 62 +/- 12%). Echocardiographically determined cardiac index increased from 2.8 +/- 0.74 to 4.1 +/- 1.74 l/min/m2. A decrease in LV excentricity indices (end diastolic: 1.9 +/- 1 vs. 1.1 +/- 0.3, end systolic: 1.7 +/- 0.6 vs. 1.1 +/- 0.4, p < 0.05) proved a normalization of preoperatively altered septum motion. LV diastolic filling returned to normal limits: (E/A ratio: 0.62 +/- 0.34 vs. 1.3 +/- 0.8; p < 0.05); Peak E velocity: 0.51 +/- 0.34 vs. 0.88 +/- 0.28 m/sec, p < 0.05; Peak A velocity: 0.81 +/- 0.36 vs. 0.72 +/- 0.42 m/sec, ns; E deceleration velocity: 299 +/- 328 vs. 582 +/- 294 cm/sec2, p < 0.05; Isovolumic relaxation time: 134 +/- 40 vs. 83 +/- 38 m/sec, p < 0.05). We could show a marked decrease in RV afterload shortly after PTE with a profound recovery of right ventricular systolic function--even in case of severe pulmonary hypertension. A decrease in paradoxic motion of the interventricular septum and normalization of LV diastolic filling pattern resulted in a significant increase of cardiac index.     

Xanthogranulomatous pyelonephritis in a renal allograft recipient

PURPOSE: To describe the occurrence of Coats-like exudative retinopathy secondary to underlying retinitis pigmentosa in a 4-year-old child. METHOD: Case report. RESULTS: A 4-year-old girl had bilateral exudative retinal telangiectasia requiring photocoagulation. She subsequently developed progressive nyctalopia, photophobia, and reduced peripheral vision. Electroretinography and dark adaptometry at age 8 years confirmed the diagnosis of retinitis pigmentosa. CONCLUSIONS: Coats-like exudative retinopathy secondary to retinitis pigmentosa can manifest as early as age 4 years and can precede the diagnosis of the underlying retinal dystrophy.     

Differences in caries recording with and without bitewing radiographs. A study on 5-year old children in the County of Bohusl?n, Sweden

OBJECTIVE: To evaluate the cerebral blood flow parameters assessed by transcranial Doppler during aortic cross-clamping and unclamping in patients undergoing abdominal aortic aneurysmectomy. METHODS: Invasive intraoperative monitoring of mean arterial pressure (MAP) and PaCO2, and right middle cerebral artery (RMCA) monitoring of blood flow parameters (mean velocity "Vm" and pulsatility index "PI") by transcranial Doppler were performed as well as evaluation of the four parameters during these subsequent periods: pre-cross-clamping, pre-unclamping, unclamping and 1-5-10-20 minutes after abdominal aortic unclamping. RESULTS: No significative changes of MAP, PaCO2, Vm and PI were noticed during the aortic cross-clamping period (77.5 +/- 18.5 SD minutes). During aortic unclamping Vm and MAP decreased (64 +/- 20 vs 52 +/- 20 cm/sec, p < 0.05, and 101 +/- 8 vs 80 +/- 15 mmHg, p < 0.01, respectively). At the 1th post-unclamping minute there was an increase from pre-unclamping values of Vm (75 +/- 20 cm/sec, p < 0.05) and PaCO2 (42 +/- 1.5 vs 36 +/- 2 mmHg, p < 0.05), with persistent reduction of MAP (92 +/- mmHg, p < 0.05), even more evident at the 5th post-unclamping minute (Vm = 93 +/- 25 cm/sec; PaCO2 = 46 +/- 1.2 mmHg, p < 0.001, and MAP returned to pre-unclamping value), in which there was also a decrease of PI (0.65 +/- 0.16 vs 0.78 +/- 0.2, p < 0.05). At the 10th minute Vm (83 +/- 24 cm/sec, p < 0.02) and PaCO2 (41 +/- 1.5 mmHg, p < 0.05) increments were present together with persistent reduction of PI (0.69 +/- 0.17, p < 0.05), while at the 20th post-unclamping minute also Vm, PaCO2 and PI returned to their pre-unclamping values. CONCLUSIONS: The Vm decrease at aortic unclamping might correlate with the acute changes in MAP (blood steal hypovolemia) and is likely due to an inadequate cerebral autoregulatory response to abrupt MAP changes. The arterial CO2 increase after aortic unclamping could lead to a dilation of cerebral arterioles and a rise of CBF (increase of Vm and decrease of PI). Transcranial Doppler is a simple and reliable technique for the monitoring of cerebral blood flow parameters and seems to be quite suitable for the recognition and the quantification of changes in these parameters induced by surgical manoeuvres able to produce hemodynamic instability.     

Aqueous flare in retinitis pigmentosa

BACKGROUND: The purpose of this study was to quantify blood-ocular barrier impairment by measuring aqueous flare in retinitis pigmentosa (RP) and to search for clinical correlations. METHODS: Forty-nine patients (94 eyes) with RP and 85 normal controls were examined. Aqueous flare was quantified with the noninvasive laser flare-cell meter (FC-1000, Kowa, Japan). Degrees of cystoid macular edema (CME), vitreous pigment dusting (VPD), intraretinal migration of retinal pigment epithelium, and waxy pallor of the optic nerve head were determined semiquantitatively by biomicroscopy. Data were analyzed using the t-test the Mann-Whitney U-test, the chi-squared test and regression analysis by taking into account the dependency of data from two eyes of the same patients. RESULTS: Aqueous flare (photon counts/ms) was significantly higher in RP (mean 10.11 +/- 3.53) than in normals (3.89 +/- 0.94; P < 0.001). Clinically significant CME was present in 26% of eyes with RP, being significantly more frequent in autosomal dominant RP (11 of 16 eyes, 69%) than in other variants (17%; P < 0.005). Multivariate analysis revealed that CME was most strongly associated with flare values (r = 0.84), P < 0.01), whereas--after adjusting for CME--correlations between aqueous flare and other clinical findings did not reach significance. CONCLUSION: RP eyes show increased aqueous flare values, indicating impairment of blood-occur barriers. This appears to be associated with CME and with autosomal dominant RP.     

Clinical findings and hemodynamic changes associated with severe occlusive carotid artery disease

OBJECTIVE: The purpose of the study was to evaluate the ophthalmologic findings and to analyze the retrobulbar hemodynamics of patients with severe (greater than 70% stenosis) occlusive carotid artery disease (OCAD) by means of color Doppler imaging (CDI). DESIGN: A case-controlled study. PARTICIPANTS: Fifty-six consecutive patients with severe OCAD and an age- and sex-matched control group consisting of 56 healthy patients without OCAD were studied. INTERVENTION: All 112 patients underwent a complete ophthalmologic examination. Color Doppler imaging of both orbits was performed by one masked investigator. MAIN OUTCOME MEASURES: Peak systolic velocity, end diastolic velocity, and the resistive index of the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. The authors compared the hemodynamic parameters measured in patients with severe OCAD with those obtained in the control group. The hemodynamic parameters of patients with asymmetric OCAD (stenosis > 70% in one internal carotid artery and stenosis < 50% in the contralateral artery) were also compared. In an attempt to determine risk factors associated with the ocular ischemic syndrome (OIS), the authors compared patients with severe OCAD and OIS with patients with severe OCAD without OIS. RESULTS: Peak systolic and end diastolic velocities in the ophthalmic, central retinal, and temporal short posterior ciliary arteries were significantly lower in patients with severe OCAD (P < 0.01). The mean resistive indices in the central retinal and temporal short posterior ciliary arteries were higher in the group with severe OCAD (P < 0.01). Similar results were obtained in the analysis of 25 patients with asymmetric carotid stenosis. Younger age (P = 0.012), severe bilateral OCAD (P = 0.01), high-grade carotid stenosis (P = 0.013), and reversed ophthalmic artery flow (P = 0.038) were significant risk factors for OIS. CONCLUSIONS: Patients with severe OCAD show hemodynamic changes that suggest reduced retrobulbar blood flow. Patients with severe bilateral OCAD, high-grade carotid stenosis, and reversed ophthalmic artery flow may have a greater risk of developing OIS.     

In vivo cell tracking by scanning laser ophthalmoscopy: quantification of leukocyte kinetics

PURPOSE: To image peripheral blood leukocyte traffic in the normal retinal and choroidal vasculature and to quantify the differences in the circulation dynamics between normal and concanavalin A (ConA)-activated leukocytes. METHODS: Normal or ConA-activated splenocytes were fluorescently labeled in vitro with 6-carboxyfluorescein diacetate (CFDA) and reinfused in vivo where they were tracked in the retinal and choroidal circulations of syngeneic rats by means of a scanning laser ophthalmoscope (SLO). Simultaneous digital and video images were captured for as long as 30 minutes, and the initial 15 seconds of image sequences and leukocyte dynamics were analyzed from digitized images by recording the velocity of trafficking cells and the number of stationary cells that accumulated with time, using a customized software package. RESULTS: Mean velocity (+/-SD) was 29.8 +/- 15.3 mm/sec in the retinal arteries, 14.7 +/- 7.2 mm/sec in the retinal veins, and 3.0 +/- 3.6 mm/sec in the retinal capillaries. Mean velocity in the choroidal vessels was 6.1 +/- 6.0 mm/sec. No significant difference in leukocyte velocity was found between activated and normal leukocytes in any of the vessel systems. However, activated leukocytes were observed to accumulate more within the choroidal vasculature (P < 0.001) and the retinal capillaries (P < 0.001) than in control animals, but not in larger retinal vessels. CONCLUSIONS: A technique to measure the kinetics of circulating leukocytes in vivo has been developed. Although leukocyte activation itself is insufficient to cause slowing of leukocyte velocity, the data indicate that leukocyte adherence to endothelium can be induced in the absence of local or systemic activating stimuli.     

Intraoral non-Hodgkin''s lymphoma in seven patients with acquired immunodeficiency syndrome

Transcranial Doppler sonography (TCD) of the middle, anterior and posterior cerebral arteries and of the basilar artery was used to evaluate the mean blood velocity (V mean) and the pulsatility index [PI = (V systolic-V diastolic)/V mean] as a vascular resistance index in 63 patients (male 40, female 23, mean age 43 +/- 19 y) with bacterial meningitis (n = 33, including 2 patients with fungal meningitis) and viral meningitis (n = 30) within 12 h after admission of the patients. The findings were similar for all intracranial arteries. Compared with reference values of 69 healthy volunteers [V mean of middle cerebral artery [MCA] 57 +/- 13 cm/s, MCA-PI 0.83 +/- 0.15], MCA-V mean was increased in patients with Glasgow coma scale (GCS) scores of 14 and 15 (71 +/- 18 cm/s; t-test: p < 0.001), not significantly different in the patients with GCS scores of 10-13 (55 +/- 21 cm/s) and decreased in those with GCS scores of 3-9 (42 +/- 21 cm/s, p < 0.01). The MCA-PI increased from 0.93 +/- 0.22 in the patients with GCS scores of 14-15 to 2.81 +/- 2.06 in those with GCS scores of 3-9 (p < 0.001 vs. controls). By regression analysis, MCA-V mean decreased and MCA-PI increased with decreasing GCS scores (p < 0.001). Only in patients with bacterial meningitis was the Glasgow outcome scale (GOS) score lower the more the MCA-PI was increased (regression analysis p < 0.001). We conclude that in patients with bacterial and viral meningitis, and in a good clinical state, the cerebral blood flow seems increased by hyperemia; with clinical deterioration the cerebral haemodynamics worsen. However, the early assessment of the cerebral blood flow by TCD seems useful for predicting outcome in bacterial meningitis only.     

Diastolic dysfunction in patients with chronic kidney failure on a hemodialysis program

OBJECTIVE: The aim of this study was to analyse different ultrasound parameters for the assessment of isolated left ventricular diastolic dysfunction (LVDD) in patients with chronic renal failure (CRF) on periodic hemodialysis (HD), comparing pulsed wave Doppler with pulsed tissue Doppler. MATERIALS AND METHODS: Forty-seven patients with CRF on HD (61% were male; mean age was 51.0 +/- 16.5 years, mean HD time--3.7 +/- 3.8 years, 38% had hypertension, 17% had diabetes) were studied by echocardiography (bidimensional, M-Mode, flow pulsed Doppler and tissue Doppler imaging). All patients had symptoms of left heart failure-class II NYHA, were in sinus rhythm and had no symptoms of ischemic heart disease. The presence of abnormal LV regional contractility was the exclusion criteria. According to their mitral inflow profile Doppler characteristics, patients were included in two groups: Group A (E/A > 1; n = 21) and B (E/A < 1; n = 26). We compared: LV dimensions and function, left atrial (LA) dimension. Gaasch index, LV mass index. E and A wave velocities (in flow pulsatile Doppler and tissue Doppler). E/N ratio in tissue Doppler, isovolumetric relaxation time (IVRT) and deceleration time (DT). RESULTS: There were no significant differences in the prevalence of age > or = 65 years male sex, hypertension or diabetes between group A and B patients, and almost all patients were on hemodialytic treatment for more than one year (81% vs 85%: NS). LV hypertrophy was present in almost all group A and B patients (A--95% vs B--85.5%; NS). Group A, compared with group B, had a difference in the Gaasch index (2.45 +/- 0.3 vs 2.08 +/- 0.4; p < 0.05), E wave velocity in flow pulsatile Doppler and tissue Doppler (cm/sec) (110 +/- 27 vs 62 +/- 20; p < 0.001 and 41 +/- 15 vs 28.5 +/- 16; p < 0.05), E/A ratio in tissue Doppler (1.3 +/- 0.4 vs 0.8 +/- 0.3; p < 0.001). IVRT (msec) (80.7 +/- 15.2 vs 113.5 +/- 28.3; p < 0.001) and DT (msec) (189.7 +/- 24 vs 278.2 +/- 17.9; p < 0.001). According to the E'/A' ratio in tissue Doppler, group A patients were divided in another two groups: E'/A' > 1 (13/21--62%) and < 1 (8/21--38%) and a significantly longer IVRT (75.8 +/- 9.3 vs 100.9 +/- 3.2; p < 0.001) and DT (178 +/- 15 vs 240 +/- 20; p < 0.001) and a greater LA dimension (37.6 +/- 6.9 vs 44.6 +/- 6.9; p < 0.05) were found. CONCLUSIONS: Pulsed wave Doppler is the most useful non invasive method for assessment of global diastolic dysfunction. In our study, 17% of the patients had E/A < 1 only in the tissue Doppler study. These patients probably had a pseudonormal mitral pattern.     

Serial lung function and elastic recoil 2 years after lung volume reduction surgery for emphysema

STUDY OBJECTIVE: To evaluate serial lung function studies, including elastic recoil, in patients with severe emphysema who undergo lung volume reduction surgery (LVRS). To determine mechanism(s) responsible for changes in airflow limitation. METHODS: We studied 12 (10 male) patients aged 68+/-9 years (mean+/-SD) 6 to 12 months prior to and at 6-month intervals for 2 years after thoracoscopic bilateral LVRS for emphysema. RESULTS: At 2 years post-LVRS, relief of dyspnea remained improved in 10 of 12 patients, and partial or full-time oxygen dependency was eliminated in 2 of 7 patients. There was significant reduction in total lung capacity (TLC) compared with pre-LVRS baseline, 7.8+/-0.6 L (mean+/-SEM) (133+/-5% predicted) vs 8.6+/-0.6 L (144+/-5% predicted) (p=0.003); functional residual capacity, 5.6+/-0.5 L (157+/-9% predicted) vs 6.7+/-0.5 L (185+/-10% predicted) (p=0.001); and residual volume, 4.9+/-0.5 L (210+/-16% predicted) vs 6.0+/-0.5 L (260+/-13% predicted) (p=0.000). Increases were noted in FEV1, 0.88+/-0.08 L (37+/-6% predicted) vs 0.72+/-0.05 L (29+/-3% predicted) (p=0.02); diffusing capacity, 8.5+/-1.0 mL/min/mm Hg (43+/-3% predicted) vs 4.2+/-0.7 mL/min/mm Hg (18+/-3% predicted) (p=0.001); static lung elastic recoil pressure at TLC (Pstat), 13.7+/-0.5 cm H2O vs 11.3+/-0.6 cm H2O (p=0.008); and maximum oxygen consumption, 8.7+/-0.8 mL/min/kg vs 6.9+/-1.5 mL/min/kg (p=0.03). Increase in FEV1 correlated with the increase in TLC Pstat/TLC (r=0.75, p=0.03), but not with any baseline parameter. CONCLUSION: Two years post-LVRS, there is variable clinical and physiologic improvement that does not correlate with any baseline parameter. Increased lung elastic recoil appears to be the primary mechanism for improved airflow limitation.     

Hamstrings and psoas lengths during normal and crouch gait: implications for muscle-tendon surgery

OBJECTIVE: To study the relative contribution of the lung and the chest wall on the total respiratory system mechanics, gas exchange, and work of breathing in sedated-paralyzed normal subjects and morbidly obese patients, in the postoperative period. SETTING: Policlinico Hospital, University of Milan, Italy. METHODS: In ten normal subjects (normal) and ten morbidly obese patients (obese), we partitioned the total respiratory mechanics (rs) into its lung (L) and chest wall (w) components using the esophageal balloon technique together with airway occlusion technique, during constant flow inflation. We measured, after abdominal surgery, static respiratory system compliance (Cst,rs), lung compliance (Cst,L), chest wall compliance (Cst,w), total lung (Rmax,L) and chest wall (Rmax,w) resistance. Rmax,L includes airway (Rmin,L) and "additional" lung resistance (DR,L). DR,L represents the component due to viscoelastic phenomena of the lung tissue and time constant inequalities (pendelluft). Functional residual capacity (FRC) was measured by helium dilution technique. RESULTS: We found that morbidly obese patients compared with normal subjects are characterized by the following: (1) reduced Cst,rs (p < 0.01), due to lower Cst,L (55.3 +/- 15.3 mL x cm H2O-1 vs 106.6 +/- 31.7 mL x cm H2O-1; p < 0.01) and Cst,w (112.4 +/- 47.4 mL x cm H2O-1 vs 190.7 +/- 45.1 mL x cm H2O-1; p < 0.01); (2) increased Rmin,L (4.7 +/- 3.1 mL x cm H2O x L-1 x s; vs 1.0 +/- 0.8 mL x cm H2O x L-1 x s; p < 0.01) and DR,L (4.9 +/- 2.6 mL x cm H2O x L-1 x s; vs 1.5 +/- 0.8 mL x cm H2O x L-1 x s; p < 0.01); (3) reduced FRC (0.665 +/- 0.191 L vs 1.691 +/- 0.325 L; p < 0.01); (4) increased work performed to inflate both the lung (0.91 +/- 0.25 J/L vs 0.34 +/- 0.08 J/L; p < 0.01) and the chest wall (0.39 +/- 0.13 J/L vs 0.18 +/- 0.04 J/L; p < 0.01); and (5) a reduced pulmonary oxygenation index (PaO2/PAO2 ratio). CONCLUSION: Sedated-paralyzed morbidly obese patients, compared with normal subjects, are characterized by marked derangements in lung and chest wall mechanics and reduced lung volume after abdominal surgery. These alterations may account for impaired arterial oxygenation in the postoperative period.     

Transesophageal echocardiographic predictors for maintenance of sinus rhythm after electrical cardioversion of atrial fibrillation

The aim of this study was to assess the value of transesophageal echocardiography (TEE) in patients with atrial fibrillation in predicting restoration and maintenance of sinus rhythm after electrical cardioversion. TEE was performed in 62 patients with atrial fibrillation before their first elective cardioversion. Clinical variables evaluated were: age, gender, duration, and etiology of atrial fibrillation. TEE variables included: left atrial (LA) length, width, and size, LA annulus size, as well as presence of LA spontaneous contrast, thrombus and mitral regurgitation, LA appendage size and flow, and left ventricular function. Based on initial outcome of cardioversion, patients were grouped into patients who remained in atrial fibrillation and in whom sinus rhythm was restored. The latter group of patients was followed for 1 year, and grouped into patients who reverted to atrial fibrillation and in whom sinus rhythm was maintained. Successful cardioversion was achieved in 50 of 62 patients (81%). None of the clinical or TEE variables were related to initial outcome. At 1-year follow-up, 29 of 50 patients (58%) who underwent successful cardioversion continued to have sinus rhythm. The following variables were related to maintenance of sinus rhythm: duration of atrial fibrillation (6.7 +/- 7.3 vs 2.0 +/- 2.4 months; p < 0.005); LA length (6.2 +/- 0.7 vs. 5.5 +/- 1.0 cm; p < 0.008); width (5.1 +/- 0.5 vs. 4.5 +/- 0.7 cm; p < 0.002); size (26.4 +/- 5.0 vs 19.8 +/- 6.5 cm2; p < 0.0005); annulus size (4.0 +/- 0.2 vs 3.7 +/- 0.3 cm; p < 0.0005); presence of LA spontaneous contrast (13 [62%] vs 4 [14%]; p < 0.002), and LA appendage flow (19 +/- 8 vs 36 +/- 15 cm/s; p < 0.0005). In multivariate logistic regression analysis, LA annulus size, but especially LA appendage flow, were significantly associated with maintenance of sinus rhythm. Thus, in TEE-guided electrical cardioversion of atrial fibrillation, variables often used to assess thromboembolic risk may also be used to predict 1-year outcome of cardioversion.     

Scatter rejection in modular gamma cameras for use in dynamic 3D spect brain imaging system

This study examined the effects of Albunex (sonicated 5% human serum albumin) infusion on left ventricular inflow velocity by Doppler echocardiography. Left ventricular pressure and left ventricular inflow velocity were recorded simultaneously under eight different conditions in dogs: 1) baseline 1 (control), 2) Albunex 0.2 ml/kg, 3) baseline 2, 4) Albunex 0.5 ml/kg, infusion of dextran 100 ml, 5) baseline 3, 6) Albunex 0.2 ml/kg, 7) baseline 4, and 8) Albunex 0.5 ml/kg. In the normal state (no dextran), Albunex (0.2 ml/kg) caused no hemodynamic changes or inflow velocity changes. In contrast, infusion of Albunex (0.5 ml/kg) caused time velocity integrals of early filling to increase from the baseline (5.51 +/- 1.13 vs 7.19 +/- 1.14 cm, p < 0.05). After dextran infusion (100 ml), Albunex (0.2 ml/kg) caused peak early filling velocity to increase (62.4 +/- 6.9 vs 67.3 +/- 9.4 cm/sec, p < 0.05), and infusion of Albunex (0.5 ml/kg) also caused peak early filling velocity to increase from baseline (64.6 +/- 8.5 vs 73.7 +/- 14.5 cm/sec, p < 0.05). Infusion of Albunex (0.5 ml/kg) after dextran infusion caused increases in left ventricular pressure at the mitral valve opening (12.7 +/- 3.1 vs 15.2 +/- 3.3 mmHg, p < 0.05) and in left atrial driving force (13.5 +/- 3.6 vs 16.7 +/- 5.9 mmHg, p < 0.05). Clinicians should be cautious about using Albunex at doses of greater than 0.2 ml/kg when evaluating the pressure gradient of the left ventricle in patients with elevated left ventricular diastolic pressure. In patients with normal hemodynamics, Albunex infusion at doses of less than 0.2 ml/kg apparently did not affect the velocity measurement.     

Anatomy of the ocular arteries in the horse

Orbital and intrabulbar arteries were studied in 20 equine eyes by means of latex injections and methylmethacrylate casts. The orbital branches of the external ophthalmic artery arise far caudal to the posterior pole of the eyeball and present a variable topographic arrangement. The intrabulbar arteries are supplied by ciliary and choroidoretinal arteries. Dependent on their entrance into the eyeball, the ciliary arteries are subdivided into a posterior and an anterior group. The posterior ciliary arteries perforate the sclera post equatorially and consist of 4 major vessels that penetrate in the lateral, medial, dorsal and ventral meridian of the eyeball, respectively. The lateral and medial of these arteries follow a long intrabulbar trajectory after having supplied several short posterior ciliary arteries to the choroid. The anterior ciliary arteries consist of a dorsal and a ventral vessel which penetrate the eyeball in the pericorneal area. The choroidoretinal arteries form an arterial network around the optic nerve at the posterior pole of the eyeball. They give rise to all retinal arterioles and some peridiscal choroidal branches. The larger part of the choroid is supplied by branches of the posterior ciliary arteries. Additionally, the anterior choroid receives recurrent branches from an arterial circle that lies externally in the ciliary ring. The iris contains a major arterial circle formed by the lateral and medial long posterior ciliary arteries and both anterior ciliary arteries. A minor iridic arterial circle nor central retinal artery could be found in the equine eyes examined.     

Stress-induced left ventricular outflow tract obstruction: a potential cause of dyspnea in the elderly

OBJECTIVES: We sought to identify the pattern of disturbed left ventricular physiology associated with symptom development in elderly patients with effort-induced breathlessness. BACKGROUND: Limitation of exercise tolerance by dyspnea is common in the elderly and has been ascribed to diastolic dysfunction when left ventricular cavity size and systolic function appear normal. METHODS: Dobutamine stress echocardiography was used in 30 patients (mean [+/-SD] age 70 +/- 12 years; 21 women, 9 men) with exertional dyspnea and negative exercise test results, and the values were compared with those in 15 control subjects. RESULTS: Before stress, left ventricular end-diastolic and end-systolic dimensions were reduced, fractional shortening was increased, and the basal septum was thickened (2.3 +/- 0.5 vs. 1.4 +/- 0.2 cm, p < 0.001, vs. control subjects) in the patients, but posterior wall thickness did not differ from that in control subjects. Left ventricular outflow tract diameter, measured as systolic mitral leaflet septal distance, was significantly reduced (13 +/- 4.5 vs. 18 +/- 2 mm, p < 0.001). Isovolumetric relaxation time was prolonged, and peak left ventricular minor axis lengthening rate was reduced (8.1 +/- 3.5 vs. 10.4 +/- 2.6 cm/s, p < 0.05), suggesting diastolic dysfunction. Transmitral velocities and the E/A ratio did not differ significantly. At peak stress, heart rate increased from 66 +/- 8 to 115 +/- 20 beats/min in the control subjects, but blood pressure did not change. Transmitral A wave velocity increased, but the E/A ratio did not change. Left ventricular outflow tract velocity increased from 0.8 +/- 0.1 to 2.0 +/- 0.2 m/s, and mitral leaflet septal distance decreased from 18 +/- 2 to 14 +/- 3 mm, p < 0.001. In the patients, heart rate rose from 80 +/- 12 to 132 +/- 26 beats/min and systolic blood pressure from 143 +/- 22 to 170 +/- 14 mm Hg (p < 0.001 for each), but left ventricular dimensions did not change. Peak left ventricular outflow tract velocity increased from 1.5 +/- 0.5 m/s (at rest) to 4.2 +/- 1.2 m/s; mitral leaflet septal distance fell from 13 +/- 4.5 to 2.2 +/- 1.9 mm (p < 0.001); and systolic anterior motion of mitral valve appeared in 24 patients (80%) but in none of the control subjects (p < 0.001). Measurements of diastolic function did not change. All patients developed dyspnea at peak stress, but none developed a new wall motion abnormality or mitral regurgitation. CONCLUSIONS: Although our patients fulfilled the criteria for "diastolic heart failure," diastolic dysfunction was not aggravated by pharmacologic stress. Instead, high velocities appeared in the left ventricular outflow tract and were associated with basal septal hypertrophy and systolic anterior motion of the mitral valve. Their appearance correlated closely with the development of symptoms, suggesting a potential causative link.     

Short deceleration time of mitral inflow E velocity: prognostic implication with atrial fibrillation versus sinus rhythm

The present study retrospectively identified 367 patients who had restrictive physiology as defined by deceleration time < or = 130 msec; 293 were in sinus rhythm (SR) (194 men and 99 women; mean age 64 +/- 14 years) and 74 were in atrial fibrillation (AF) (51 men and 23 women; mean age 72 +/- 11 years; p < 0.001). Both groups had similar underlying diagnoses and no significant difference in Doppler indices (E wave, 96 +/- 23 vs 99 +/- 22 cm/sec in SR and AF, respectively; deceleration time, 116 +/- 12 vs 116 +/- 13 msec; and left ventricular outflow tract time velocity integral, 14.8 +/- 4.8 vs 14.5 +/- 4.4 cm). Left ventricular ejection fraction was significantly lower in SR patients (29% +/- 16% vs 39% +/- 20%; p = 0.0003). There were 120 deaths (41%) in the SR group and 35 (47%) in the AF group (median follow-up for both groups, 2.2 years). Restrictive physiology as defined by Doppler echocardiography (deceleration time < or = 130 msec) appears to predict a similar poor prognosis with AF as with SR.     

Bioelectrical impedance analysis of body composition in patients with pulmonary emphysema

In this study we utilized bioelectrical impedance analysis (BIA) to compare the body composition of 36 stable pulmonary emphysema (PE) patients with 19 healthy controls. We compared the PE patients and healthy controls in terms of fat-free mass (FFM) and body fat (BF) as percentages of ideal body weight (FFM/IBW, BF/IBW). FFM/IBW and BF/IBW were significantly lower in the PE patients than in the controls (75.0 +/- 9.8% vs. 85.2 +/- 7.3%, p < 0.001 and 11.8 +/- 6.4% vs. 16.7 +/- 7.7%, p < 0.05, respectively). We divided the PE patients into two subgroups according to FFM, then investigated the relationships between FFM and skeletal muscle strength, and between FFM and respiratory muscle strength. In patients with reduced FFM (FFM < 43.5 kg) grip strength as an index of skeletal muscle strength was significantly lower than in patients without reduced FFM (FFM > or = 43.5 kg) (25.7 +/- 7.8 kg vs. 36.2 +/- 7.2 kg, p < 0.005). As indexes of respiratory muscle strength, maximal expiratory pressure (PEmax) and maximal inspiratory pressure (PImax) were lower in the patients with reduced of FFM, but not to a statistically significant degree (49.6 +/- 20.8 cm H2O vs. 58.7 +/- 23.9 cm H2O and 40.5 +/- 19.2 cm H2O vs. 50.2 +/- 22.1 cm H2O, respectively). In the PE patients, FFM correlated closely with vital capacity (r = 0.528, p < 0.001), forced vital capacity (FVC) (r = 0.531, p < 0.001), FEV1.0 (r = 0.554, p < 0.001), FEV1.0/FVC (r = 0.467, p < 0.005), RV/TLC (r = -0.395, p < 0.05), DLco (r = 0.770, p < 0.001), and DLco/VA (r = 0.622, p < 0.001). However no correlation was observed between BF and any of the measures of lung function. The findings of our study suggest that FFM correlates with skeletal muscle strength, respiratory muscle strength and some measures of lung function in patients with PE, and that assessments of body composition are valuable to their clinical management.