New noninvasive method for coronary flow reserve assessment: contrast-enhanced transthoracic second harmonic echo Doppler

BACKGROUND: We tested the hypothesis that blood flow velocity could be recorded in the left anterior descending coronary artery (LAD) during transthoracic echocardiography by use of second harmonic echo Doppler modality along with contrast enhancement (intravenous Levovist) at rest and after pharmacologically induced maximal vasodilation to assess coronary flow reserve (CFR) with a totally noninvasive approach. METHODS AND RESULTS: Fifty-six consecutive patients undergoing coronary angiography underwent transthoracic contrast-enhanced pulsed-wave Doppler recording of blood flow velocity in the LAD by use of harmonic color Doppler as a guide at rest and after maximal vasodilation by dipyridamole infusion. Contrast enhancement with the harmonic mode greatly improved the success rate of recording adequate pulsed-wave Doppler signal in the LAD. CFR was (mean+/-SD) 1.54+/-0.7 in patients with (group 1) and 2. 79+/-0.9 in patients without (group 2) significant LAD stenosis (lumen narrowing >70%) (P<0.001); sensitivity and specificity in detecting significant LAD stenosis were 86% and 90%, respectively. There was close agreement between CFRs determined by this new method and intracoronary Doppler flow wire. CONCLUSIONS: Contrast-enhanced transthoracic echo Doppler with the harmonic mode is a feasible and promising technique for assessing CFR in a totally noninvasive way.     

An investigation of ethnic and gender differences in the pharmacodynamics of haloperidol

To observe pulmonary venous flow in dogs, the echocardiographic imaging planes and the techniques for examination, and the validations of anatomic location were investigated. Then, the velocity pattern of pulmonary venous flow was recorded in normal conscious dogs. Six imaging planes were available for observing the right or left caudal lobe pulmonary venous flow with two-dimensional or pulsed Doppler echocardiography. Of these, the left lateral apical 4-chamber view can be applied as standard view, because the pulmonary venous flow and transmitral flow could be recorded in this view simultaneously with small sampling angle. The velocity pattern of pulmonary venous flow demonstrated two forward waves in 19 of 20 dogs examined, with one peak occurring during ventricular systole and another during ventricular diastole. A reversed flow during atrial contraction was also seen in 11 dogs. In the two forward waves, the mean peak velocity and velocity-time integral of ventricular diastolic forward flow were significantly higher than those of systolic forward flow (46.49 +/- 6.79 vs. 31.13 +/- 4.92 cm/s, p < 0.0001 and 8.18 +/- 1.84 vs. 5.14 +/- 0.82 cm, p < 0.0001, respectively). The deceleration time of diastolic forward flow shortened with the increase of heart rate (r = -0.87, p < 0.0001). Pulmonary venous flow in dogs can be observed under transthoracic two-dimensional or pulsed Doppler echocardiography.     

Usefulness of multiplane transesophageal echocardiography to improve the assessment of severity of mitral regurgitation

This study was designed to examine the accuracy of multiplane transesophageal echocardiography (TEE) color Doppler measurements in comparison to monoplane or biplane measurements in estimating the severity of mitral regurgitation (MR). Multiplane TEE potentially increases diagnostic accuracy of transesophageal examinations; it is unknown if multiplane is more accurate in assessing the severity of MR than monoplane or biplane TEE. Left ventricular cineangiograms of 91 patients with MR (40 no or mild, 30 moderate, and 21 severe) were compared with systolic pulmonary venous flow reversal and transesophageal color Doppler measurements: jet area and length in the transverse and longitudinal plane, maximal and average of those 2 planes (biplane), and maximal and average of 11 different planes (multiplane). Flow reversal (16 patients) identified severe MR with a specificity of 96% and a sensitivity of 62%; these were 96% and only 10% to 43%, respectively, for color Doppler measurements. In the absence of flow reversal, multiplane maximal jet area predicted severe MR with a sensitivity of 88% and a specificity of 75%, which were 85% and 76%, respectively, for no or mild MR; this did not differ significantly from results obtained by monoplane or biplane measurements. Color Doppler measurements of eccentric jets were not reliable for identification of severe MR. Systolic pulmonary venous flow reversal identifies 2 of 3 patients with severe MR with a high accuracy. In patients without flow reversal, multiplane color Doppler TEE is very capable of assessing MR severity, but biplane and monoplane TEE are equally accurate.     

The comparative value of transesophageal and transthoracic echocardiography before and after percutaneous mitral balloon valvotomy: a prospective study

Transthoracic (TTE) and transesophageal echocardiography (TEE) were performed prospectively on 53 consecutive patients (mean age 59 +/- 14 years) immediately before and within 24 hours of mitral balloon valvotomy to compare the relative value of the two techniques. Biplane TEE was used in 38 patients and single-plane imaging was done in 11. All patients underwent left and right cardiac catheterization, left ventriculography, and coronary angiography. While TEE provided excellent images of the mitral valve in all patients, imaging planes were more limited than by TTE. Mitral valve morphology could be assessed satisfactorily by either technique. Echo scores derived from each showed good correlation (r = 0.90, p < 0.001). TEE transgastric longitudinal scanning provided superior detail of the subvalvar apparatus but only in 20 (53%) of 38 patients. Patients with good transgastric views had significantly smaller left atrial volumes than those without (58 +/- 22 vs 106 +/- 41 cm3, p < 0.001). Mitral valve orifice and the commissures were better assessed by TTE. Before valvotomy, mitral regurgitation (MR) graded by TEE and TTE color flow mapping was concordant with angiography in 80% and 81%, respectively. After valvotomy, TTE color flow mapping failed to detect MR in two of the three patients who developed severe MR. Two of these patients were examined by TEE, which demonstrated both the MR jets as well as leaflet tears. Thrombus was diagnosed in the left atrium in eight patients by TEE and in only one patient by TTE. Biplane TEE was required for accurate thrombus localization and for assessing its size and extent. Five patients with thrombus underwent balloon valvotomy without complications. Left-to-right atrial shunting was detected by TEE and TTE in 95% and 48% of patients, respectively. Flow convergence regions, from which quantitative flow information can be derived, were imaged by TEE only. TTE and TEE have complementary roles. However, TEE is essential for excluding thrombus in the left atrium before balloon valvotomy. After the procedure, TEE is recommended for the evaluation of patients with severe mitral regurgitation.     

Simultaneous measurement of pulmonary venous flow by intravascular catheter Doppler velocimetry and transesophageal Doppler echocardiography: relation to left atrial pressure and left atrial and left ventricular function

OBJECTIVES: The aim of our study was to compare measurements of pulmonary venous flow velocity obtained either by transesophageal Doppler echocardiography or by intravascular catheter Doppler velocimetry. Furthermore, the relation among pulmonary venous flow velocity, left atrial compliance and left atrial pressure was evaluated. BACKGROUND: Data about the relation between left atrial pressure and pulmonary venous flow velocity are controversial. METHODS: A total of 32 patients undergoing elective open heart surgery for coronary artery bypass grafting were included prospectively in the study. Pulmonary venous flow velocity (Doppler catheter) and left atrial pressure (microtip pressure transducer) were recorded simultaneously with recordings of pulmonary venous flow velocity obtained by transesophageal Doppler echocardiography. RESULTS: Agreement between Doppler catheter and Doppler echocardiographic measurements of pulmonary venous flow velocity (n = 18 patients) was analyzed using the Bland-Altmann technique. The 95% limits of agreement were -0.16 to +0.11 m/s for systolic peak velocity, -0.14 to +0.09 m/s for diastolic peak velocity and -0.12 to +0.10 m/s for atrial peak velocity. The closest agreement between both methods was found for the ratio of systolic to diastolic peak velocity, the ratio of systolic to diastolic flow duration and the time from Q deflection on the electrocardiogram to maximal flow velocity. Mean left atrial pressure was strongly correlated with the ratio of systolic to diastolic peak velocity (r = -0.829), systolic velocity-time integral (r = -0.653), time to maximal flow velocity (r = 0.844) and the ratio of systolic to diastolic flow duration (r = -0.556). The ratio of systolic to diastolic peak velocity and the time to maximal flow velocity were identified as strong independent predictors of mean left atrial pressure. Left atrial compliance was not found to be an independent predictor of mean left atrial pressure. CONCLUSIONS: Flow velocity in the left upper pulmonary vein can be reliably recorded by transesophageal pulsed wave Doppler echocardiography. Our data reveal further evidence that mean left atrial pressure can be estimated by the pattern of pulmonary venous flow velocity.     

Metabolites of ebrotidine, a new H2-receptor antagonist, in human urine

The clinical application of ultrasonographic contrast agents in colour Doppler flow imaging of hepatic tumours is receiving increasing attention. Levovist is a suspension of galactose microparticles that provides reproducible concentrations of stabilized air bubbles with transpulmonary stability. Its effect on colour Doppler imaging was assessed in 26 patients with colorectal cancer and histologically proven hepatic metastases. Colour Doppler flow imaging was performed before and after intravenous injection of 10 ml Levovist 300 mg/ml. At 5-10 s after injection there was significant enhancement of the hepatic lesions with colour Doppler signals in 23 patients, lasting for a mean(s.d.) of 180(45) s. A consistent pattern of colour Doppler signal was observed, with increased enhancement predominantly around the tumour periphery and little or no central enhancement. These data suggest that Levovist may increase the sensitivity and specificity of colour Doppler flow imaging of colorectal hepatic metastases.     

Frequency of deep vein thrombosis in patients with patent foramen ovale and ischemic stroke or transient ischemic attack

To evaluate the additional value of transesophageal (TEE) compared with transthoracic (TTE) echocardiography and the role of patent foramen ovale (PFO) and deep vein thrombosis in the work-up of embolic events, patients with presumed cardiac embolic stroke or transient ischemic attack (neurovascular etiology was excluded) were prospectively studied by transthoracic and transesophageal contrast echocardiography. If PFO was detected echocardiographically, PFO size was assessed semiquantitatively and phlebography of both legs was performed. Two hundred forty-two consecutive patients (153 men, 60 +/- 15 years) were studied. In 197 patients, neuroimaging showed evidence of embolic infarction. TEE identified 138 potential cardiac sources of embolism in 111 patients, compared with 69 by TTE (p <0.01) in 59 patients. TEE detected potential cardiac sources in 52 patients with negative TTE examination and was significantly superior compared with TTE for identifying left atrial thrombi, spontaneous echo contrast, PFO, atrial septal aneurysm, and atheroma of the ascending aorta. In patients with a positive TTE, additional diagnostic information by TEE was found in only 6 patients and did not change therapy. Phlebography was performed in 53 patients with PFO and revealed deep vein thrombosis in 5 patients (9.5%); all had medium or large PFOs. Thus, in patients with cerebral ischemia of suspected cardiogenic origin and a normal TTE examination, TEE detects potential causes of embolism in 31% of patients and is therefore of diagnostic relevance. Conversely, in the presence of a diagnostic TTE an additional TEE confers only marginal diagnostic benefit. Deep venous thrombosis was detected in nearly 10% of patients with PFO as the sole identifiable cardiac risk factor. Given that in 4 of 5 patients deep vein thrombosis was clinically silent, phlebography should be performed in patients with medium or large interatrial shunts if paradoxical embolism is suspected.     

Doppler analysis of pulmonary venous flow profiles in orthotopic heart transplant recipients: a comparison with mitral flow profiles and atrial function

Previous Doppler studies of transmitral flow profiles in heart transplant recipients suggested left ventricular (LV) diastolic dysfunction. The influence of left atrial filling and emptying on mitral Doppler profiles in heart transplant recipients has not been studied systematically. In the present study, pulmonary venous flow profiles, mitral flow profiles, left atrial area change and mitral annulus motion were analyzed in 20 orthotopic heart transplant recipient and 20 control subjects by transthoracic and transesophageal echocardiography and Doppler. Mitral flow profiles revealed a "restrictive" pattern with a high early-to-late diastolic flow velocity ratio in transplant patients (2.16 +/- 0.52 vs. 1.30 +/- 0.25, p < 0.0001), which was mainly due to a reduced late diastolic maximum mitral flow velocity (32.6 +/- 8.3 vs. 51.6 +/- 12.4 cm/s, p < 0.0001). Left atrial area change (35.9 +/- 13.9 vs. 58.1 +/- 17.0%, p < 0.0006) and mitral annulus motion (9.2 +/- 3.3 vs. 12.2 +/- 2.0%, p < 0.05) were reduced in transplant recipients, compared to controls. Pulmonary venous flow parameters in transplant recipients were markedly altered during systole, when pulmonary venous flow parameters are influenced primarily by atrial function rather than by diastolic LV properties: peak systolic flow velocity (45.5 +/- 8.2 vs. 62.3 +/- 14.0 cm/s, p < 0.001), maximum flow velocity ratio (0.87 +/- 0.19 vs. 1.45 +/- 0.33), time velocity integral of pulmonary venous flow during systole (9.3 +/- 2.3 vs. 17.1 +/- 4.0 cm, p < 0.001) and the systolic fraction of the time velocity integral (52.6 +/- 10.8 vs. 68.5 +/- 6.8%, p < 0.001) were lower in heart transplant recipients than in controls. These findings are compatible with atrial dysfunction and reduced mitral annulus motion. The results of this study indicate that LV diastolic dysfunction is not the only possible cause of altered transmitral Doppler profiles in heart transplant recipients. Atrial abnormalities represent a major contributing factor to altered mitral and pulmonary venous flow patterns. Analysis of transmitral Doppler profiles alone are therefore not adequate for analysis of diastolic LV function in heart transplant recipients.     

Duration of pulmonary venous atrial reversal flow velocity and mitral inflow a wave: new measure of severity of cardiac amyloidosis

Transmitral Doppler flow patterns of patients with cardiac amyloidosis evolve from an early impaired relaxation to an advanced restrictive pattern. This reflects increasing severity of diastolic dysfunction and hence left ventricular filling pressures. The duration of the pulmonary venous atrial reversal flow was recently shown to exceed that of the mitral inflow A wave in patients with left ventricular end-diastolic pressure greater than 15 mm Hg. The objective of this study was to assess the utility of this index as a measure of the severity of cardiac amyloidosis. Comprehensive transthoracic 2-dimensional and pulsed-wave Doppler echocardiograms of the pulmonary venous and transmitral flows were made of 23 patients (10 women) with biopsy-proven diagnosis of primary systemic amyloidosis and of 49 subjects as age-matched normal controls. The amyloidosis group was divided into non-restrictive and restrictive subgroups on the basis of the patients' transmitral inflow deceleration time (>150 and < or =150 ms, respectively). The durations of the pulmonary venous atrial reversal and mitral inflow A wave were measured, and the differences between the flow durations were compared with the control and published data in the nonrestrictive and restrictive groups. The mean duration of the pulmonary venous atrial reversal was significantly longer in the amyloid than the control group (P < .01). The mean duration of the mitral inflow A wave was significantly shorter in the restrictive group than both the nonrestrictive and the control groups (P < .05). The duration of the pulmonary venous atrial reversal exceeded that of the mitral inflow A wave in all patients with cardiac amyloidosis. The difference in duration between pulmonary venous atrial reversal and mitral inflow A wave was significantly greater in the amyloidosis group compared with the normal group, and this index varied significantly within the amyloid group between the abnormal relaxation and the restrictive groups. The difference in the duration between the pulmonary venous atrial reversal and the mitral inflow A wave is a reliable index of diastolic function and can be used to assess the severity of cardiac amyloidosis.     

Incidence and spectrum of spontaneous neoplasms in Han:NMRI mice of both sexes

Pulsed Doppler ultrasound has been used to characterize distinctive pulmonary venous flow patterns in the normal fetus and child. Changes in these characteristic flow patterns have been related to abnormal atrial and ventricular hemodynamics. We report a case of total anomalous pulmonary venous return diagnosed prenatally because of an abnormal pulsed Doppler echocardiographic flow pattern, even though color flow mapping appeared to demonstrate normal pulmonary venous drainage. This case demonstrates the importance of obtaining pulsed Doppler pulmonary venous flow profiles during fetal echocardiography, especially in cases of complex congenital heart disease.     

Duplication and distribution of repetitive elements and non-unique regions in the human genome

The natural history of patients with coronary artery disease and diastolic dysfunction who underwent coronary artery bypass grafting (CABG) is not well known. The aims of our study were to evaluate the incidence of diastolic dysfunction, its evolution after CABG and its possible correlation with adverse in-ICU prognosis. We studied 88 consecutive patients scheduled for CABG with not severely depressed left ventricular function (ejection fraction > 35%) and multivessels disease. Buckberg cardioplegia was used for myocardial protection. Diastolic function was investigated by recording mitral and venous pulmonary flow by transesophageal Doppler echocardiography (TEE). TEE examination was performed in operative room pre and post-bypass, at ICU arrival and after three months. Diastolic dysfunction was defined as mild, moderate and severe. Adverse in ICU events were defined as: use of inotropic drugs or ventricular mechanical support, an ICU stay > 24 hours, perioperative myocardial infarction and death. The study group was compared with a control group. T-Student test was used; a p < 0.05 was considered significant. A reduced diastolic function was present in 77% of patients at baseline examination. Diastolic dysfunction did not worsen significantly after hypothermic cardiac arrest and reperfusion. It persisted during ICU stay and normalized after three months from CABG in the majority of patients (85%). Diastolic failure was not associated with an adverse ICU prognosis (adverse events: 18 versus 13%; p = ns).     

Comparison of patterns of pulmonary venous blood flow in the functional single ventricle heart after operative aortopulmonary shunt versus superior cavopulmonary shunt

In this study we investigated the patterns of pulmonary venous flow in children with functional single ventricles to obtain a better understanding of the determinants of transpulmonary blood flow. Sixty-eight patients with functional single ventricles and aortopulmonary shunt (n = 34, group I), or superior cavopulmonary connection (n = 34, group II) underwent transesophageal Doppler echocardiographic assessment of flow in the left upper pulmonary vein before undergoing the next stage of surgery. Twelve patients from group II also underwent simultaneous evaluation of superior vena caval flow. Biphasic forward pulmonary venous flow was noted in 62 patients in sinus rhythm (S wave in systole, D wave in diastole); in 6 patients with junctional rhythm, significant early systolic reversal of flow was present. Both the S- and D-wave velocity-time integrals (VTI) were greater in group I than in group II (S(VTI) 9.9 +/- 4.2 vs 8.0 +/- 2.6, p = 0.02; D(VTI) 8.0 +/- 3.5 vs 4.2 +/- 2.6, p <0.001). In both groups, pulmonary venous flow was predominantly systolic; however, the proportion of flow during ventricular systole was significantly greater in group II than in group I (S(VTI)/D(VTI) group II: 2.4 +/- 1.5; group I 1.4 +/- 0.5, p = 0.001; percent systolic fraction of pulmonary venous flow group II = 67%, group I = 56%, p <0.001). Analysis of superior vena caval flow in group II revealed a single predominant wave with onset at early systole and peak in late systole at a mean of 150 ms after the pulmonary venous S-wave peak. Our data suggest that ventricular systole (i.e., atrial relaxation, atrioventricular valve descent) asserts great influence on transpulmonary blood flow in the functional single ventricle.     

A transesophageal Doppler echo-color study of pulmonary venous flow before and after the correction of valvular defects

AIM OF THE STUDY: To verify changes of pulmonary venous flow pattern before and after surgical or percutaneous correction of valvular heart disease. METHODS: The pulmonary venous flow pattern was studied by transesophageal echocardiography in 27 patients affected with heart valve disease (11 mitral insufficiency, 10 mitral stenosis, 2 aortic stenosis and 4 pulmonary stenosis), before and after surgical or percutaneous correction. Pulmonary venous flow velocity variables measured included peak systolic and diastolic flow velocities (VmaxS and VmaxD), systolic and diastolic velocity time integrals (IS and ID) and their respective ratios (VmaxS/VmaxD and IS/ID). Paired Student's t-test was used for analysis of data; a p value < 0.05 was considered statistically significant. RESULTS: In mitral stenosis and insufficiency, as well as in pulmonary stenosis, the VmaxS/VmaxD and IS/ID ratios were constantly < 1. Aortic stenosis, on the contrary, showed a normal preoperative pattern of pulmonary venous flow, which did not change after correction. All other successful corrections (17 surgeries, 4 angioplasties) were characterised by an increase of VmaxS/VmaxD and IS/ID ratios. (Mitral stenosis: VmaxS/VmaxD 0.80 +/- 0.31 vs 1.4 +/- 0.5, p = 0.006; IS/ID 0.86 +/- 0.77 vs 1.62 +/- 0.62, p = 0.016. Severe mitral insufficiency: VmaxS/VmaxD -0.71 +/- 0.32 vs 1.19 +/- 0.32, p < 0.0001; IS/ID 0.41 +/- 0.19 vs 1.04 +/- 0.31, p = 0.006. Moderate mitral insufficiency: VmaxS/Vmax D 0.38 +/- 0.04 vs 0.95 +/- 0.06, p = 0.001; IS/ID 0.32 +/- 0.05 vs 0.95 +/- 0.07, p = 0.02. Pulmonary stenosis: VmaxS/VmaxD 0.43 +/- 0.23 vs 1.09 +/- 0.35, n.s. e IS/ID 0.49 +/- 0.34 vs 0.92 +/- 0.65, n.s.). Failure to return to a normal pulmonary venous pattern was observed in the 2 cases of partially successful mitral valvuloplasty (one of which was subsequently transformed into a mitral valve replacement with immediate normalisation of the pattern) and in the 2 cases of incomplete relief of a pulmonary stenosis after pulmonary valvuloplasty. CONCLUSIONS: Though preliminary, these observations suggest a high sensitivity of this method and, therefore, a possible role of pulmonary venous pattern studies in the assessment of the efficacy of treatment in mitral and pulmonary valve disease.     

Clinical usefulness of transrectal sonography and transperineal color Doppler flow imaging in the diagnosis of intrapelvic venous congestion syndrome

BACKGROUND: The present study was designed to reveal the possible use of transrectal sonography (TRS) and transperineal color Doppler flow imaging in predicting intrapelvic venous congestion syndrome (IVCS), as evaluated by three dimensional magnetic resonance venography (3D-MRV). METHODS: Thirty-one patients with prostatodynia and eleven control men were enrolled in this study. The diagnosis of IVCS was made based on the findings by 3D-MRV, such as the dilation of the prostatic capsular vein, the dilation of the pudendal plexus, the interruption of the internal pudendal vein and the dilation of the plexus behind the bladder. The prostatic capsular vein was observed ultrasonically as "sonolucent zone (SZ)", and the maximum width of SZ was measured on sonograms. Transperineal color Doppler flow imaging was used to detect blood flow images of the prostatic capsular vein. The maximum velocity of it was also measured on sound spectrogram. RESULTS: IVCS was confirmed in 29 cases (IVCS group) and the other 13 cases were regarded as non-IVCS group. IVCS was recognized much more frequently in patients with prostatodynia than in controls (87% vs 18%, p < 0.0001). The maximum width of SZ was 2.4 mm (mean) in non-IVCS group, compared to 4.4 mm in IVCS group (p < 0.0001). The cutoff value of 3.0 mm for the maximum width of SZ showed as high as 86% of sensitivity for the detection of IVCS. The maximum velocity of retrograde venous flow during Valsalva's maneuver in IVCS group (mean 14.4 cm/s) was faster than non-IVCS group (mean 7.1 cm/s, p < 0.05). The cutoff value of 10 cm/s for the maximum retrograde venous flow velocity showed as high as 69% of sensitivity for the detection of IVCS. CONCLUSIONS: Both TRS and transperineal color Doppler flow imaging were usefull as a predictor for IVCS.     

Usefulness of transesophageal echocardiography in the treatment of critically ill patients

To evaluate the usefulness of transesophageal echocardiography (TEE) in the treatment of critically ill patients, 80 patients (51 male and 29 female; mean age, 53 years) undergoing both transthoracic echocardiography (TTE) and TEE were studied in a 2-year period. Of these, 48 patients were studied in the ICU, while the other 32 patients were directly referred from the emergency departments. Indications for the study included suspected aortic dissection (34 patients), hemodynamic instability (22 patients), suspected cardiac source of embolism (11 patients), evaluation of the severity of mitral regurgitation (7 patients), and suspected infective endocarditis (6 patients). The probe was passed successfully in 78 of 80 attempts (98 percent). No significant complications were recorded during the transesophageal echocardiographic study. Transesophageal echocardiography provided critical information that was not obtained by TTE in 39 of 78 studies (50 percent, p < 0.005). Cardiac surgery was prompted by TEE findings in 14 patients (18 percent) and these findings were all confirmed at operation. Transesophageal echocardiography was a safe, well-tolerated, and valuable diagnostic approach for the rapid detection of specific cardiac abnormalities in patients with critical illness; TEE should be considered in the treatment of critically ill patients especially when TTE provided inadequate information.     

Factors influencing pulmonary venous flow velocity patterns in mitral regurgitation: an in vitro study

OBJECTIVES: The aim of this study was to investigate factors affecting pulmonary venous flow patterns in mitral regurgitation. BACKGROUND: Although pulmonary venous flow velocity patterns have been reported to be helpful in assessing the severity of mitral regurgitation, the influence of regurgitant jet direction, pulmonary venous location and left atrial pressures on pulmonary venous flow patterns has yet to be clarified. METHODS: The mitral regurgitant jet was produced by a pulsatile piston pump at 10, 30 and 40 ml/beat through a circular orifice, whereas the pulmonary venous flow was driven by gravity. Four different patterns of pulmonary venous flow and mitral regurgitation were examined. The V wave pressure was set at 10, 30 and 50 mm Hg and pulmonary venous flow velocity at 30 cm/s. Color and pulsed Doppler recordings were obtained with a VingMed 800 scanner interfaced with a computer facilitating digital analysis. RESULTS: The decrease in the velocity time integral of pulmonary venous flow was more prominent for any given volume of mitral regurgitation at higher left atrial pressure. When the mitral regurgitant jet was directed toward the pulmonary vein, a more prominent decrease in the velocity time integral was seen, especially for severe mitral regurgitation (40 ml) with high left atrial pressure (95% vs. 55%, p < 0.001); and the time to peak deceleration of forward flow was significantly shorter (485 vs. 523 ms, respectively, p < 0.01). Also, two different types (laminar and turbulent) of reversed pulmonary venous flow were observed. CONCLUSIONS: Multiple factors, including jet direction, mitral regurgitant volume and left atrial pressure, determine the effect of mitral regurgitation on pulmonary venous flow velocity patterns.     

Indications for palliative reduction surgery for hepatocellular carcinoma with multiple intrahepatic metastases

It is assumed that stenosis of the right coronary artery (RCA) predisposes CABG patients, by way of incomplete atrial myocardial protection, to postoperative atrial fibrillation (AF). Sixty patients with high-grade RCA lesion were randomized into four groups according to the technique of delivery of cold blood cardioplegia: antegrade, retrograde, retrograde without catheter cuff, and combined antegrade and retrograde. As controls, 34 patients without RCA lesion were randomized to receive antegrade or retrograde cardioplegia. Postoperative atrial fibrillation episodes were recorded. Patients with RCA lesion were more prone to develop AF; odds ratio (OR)=3.75 (95% confidence interval [CI]=1.22-11.5). Retrograde delivery in these patients was more often associated with AF, OR=4.97 (95% CI = 1.02-24.1). Other risk factors for AF were an increasing number of preoperative infarcts (p < 0.05) and more advanced coronary artery disease (p < 0.05). Prolonged stay in the intensive care unit (p < 0.001) and occurrence of postoperative ventricular tachycardia (p < 0.05) were associated with AF. RCA stenosis and retrograde cardioplegia delivery in RCA-affected patients were risk factors for postoperative atrial fibrillation. Retrograde cardioplegia may offer poorer protection at the atrial level.     

Accuracy of portal and forearm blood flow measurements in the assessment of the portal pressure response to propranolol

BACKGROUND/AIMS: The portal pressure response to propranolol varies significantly in individual patients with cirrhosis. At present, propranolol responders can be identified only by measuring the hepatic venous pressure gradient. The aims of this study were: 1) to investigate whether the noninvasive monitoring of portal blood flow by pulsed Doppler ultrasound and forearm blood flow by strain-gauge plethysmography can predict the hepatic venous pressure gradient response to propranolol in patients with cirrhosis, and 2) to analyze the factors that may influence this response. METHODS: Hemodynamic measurements were undertaken in 80 patients with cirrhosis before and after receiving propranolol (0.15 mg/kg i.v., n = 60) or placebo (n = 20). RESULTS: No changes were observed in the placebo group. Propranolol lowered (p < 0.01) hepatic venous pressure gradient from 17.6 +/- 3.8 to 14.7 +/- 3.8 mmHg, portal blood flow from 1122 +/- 363 to 897 +/- 332 ml/min and forearm blood flow from 7.52 +/- 3.1 to 6.12 +/- 2.3 ml/min%. Changes in hepatic venous pressure gradient were correlated (p < 0.01) with those of portal blood flow (r = 0.82) and forearm blood flow (r = 0.54). The reduction in hepatic venous pressure gradient was > 20% in 23 patients ("responders"). The accuracy of portal Doppler flowmetry in identifying responders was higher than that of forearm plethysmography (88.3 vs. 68.3%, p < 0.05). Multivariate analysis proved that previous variceal bleeding was the only factor independently associated with a lack of response to propranolol (relative risk 3.42, 95% CI 1.5-7.4, p < 0.01). Hepatic venous pressure gradient reduction by propranolol was higher in non-bleeders than in bleeders (-19.9 +/- 9.4 vs. -11.3 +/- 8.6%, p < 0.01). CONCLUSIONS: Portal Doppler ultrasound can be used as a reliable surrogate indicator of the hepatic venous pressure gradient response to acute propranolol administration. In addition, our study indicates that this response is mainly influenced by previous variceal hemorrhage.     

Evaluation of 7,000+ patients with two different routes of cardioplegia

BACKGROUND: This study examined the efficacy and safety of retrograde cardioplegia in comparison with an antegrade/retrograde approach. METHODS: Between January 1, 1991, and December 31, 1995, 7,032 coronary artery bypass procedures, alone or in combination with valve replacement/repair, were performed using either retrograde cardioplegia (R) or an antegrade/retrograde (AR) approach. There were 4,224 patients in the R group and 2,808 in the AR group. These included elective, urgent, emergent/salvage, first operative, and redo cases. RESULTS: All preoperative, intraoperative, and postoperative variables listed in The Society of Thoracic Surgeons National Cardiac Surgery Database were used to compare the two groups using univariate analysis. The pump time was longer in the AR group, with fewer grafts per patient. The R group had higher predicted risk (3.2% versus 3.0%; p = 0.04), more postoperative atrial fibrillation (34% versus 31%; p = 0.006), and longer postoperative length of stay (8.8 versus 8.0 days; p < 0.001). Using The Society of Thoracic Surgeons National Cardiac Surgery Database predicted risk group model, a subgroup of 221 coronary artery bypass grafting patients in the retrograde (s-R) and 132 coronary artery bypass grafting patients in the antegrade/retrograde (s-AR) group fell into a greater incidence of predicted mortality group (> or = 10%). The s-R subgroup had more patients in New York Heart Association functional class IV. Univariate analysis revealed higher postoperative atrial fibrillation (51% versus 41%; p = 0.05) and longer postoperative length of stay (12.8 versus 10.8 days; p = 0.03) in the s-R subgroup versus the s-AR subgroup. CONCLUSIONS: The results appear to favor neither approach. Preoperatively, both retrograde groups (R and s-R) had higher preoperative predicted risk, but operative mortality or complications were not significantly increased when compared with the AR and s-AR groups. Retrograde cardioplegia alone was shown to be effective in the R and s-R groups, but atrial fibrillation developed in more patients, which could have contributed to longer length of stay in these groups. Antegrade/retrograde cardioplegia offers good immediate outcome but the delivery method can be cumbersome and confusing during the adjustments of flow clamps for antegrade/retrograde delivery and may contribute to prolonged pump times. From this retrospective, nonrandomized review, it appears that retrograde cardioplegia alone provides as good myocardial protection and safety as an antegrade/retrograde approach in either the low-risk or high-risk patient.     

Relationship between the flow pattern and vasomotor reactivity in the ophthalmic artery, siphon and vessels within the circle of Willis in the unilateral internal carotid artery occlusion

The aim was to study a relationship between the flow pattern in the ophthalmic artery (OA), the siphon and vessels within the circle of Willis. 27 patients, 22 males and 5 females, mean age 63 +/- 15 years (SD) with unilateral occlusion of the internal carotid artery (ICA) were examined by 3-dimensional Transcranial Doppler scanner. Flow signals from the OA, the siphon and intracranial vessels were registered before and after i.v. injection of 1 g acetazolamide. Pathological flow pattern was found in 18 patients in the OA on the occluded side consisting of 12 retrograde and 6 isoelectric flow directions. After acetazolamide injection retrograde systolic velocities (SV) increased significantly (p < 0.01), but anterograde velocities remained unchanged as did 3 isoelectric flow patterns, 2 turned to retrograde and one to anterograde flow direction. In the siphon lower resting anterograde mean velocities (MV) were found on both sides (p < 0.05) compared to normal subjects. Six patients had the same retrograde flow as in the OA. After acetazolamide MV in the siphon increased (p < 0.01) only on the nonoccluded side. Baseline retrograde ophthalmic SV and MV in the siphon correlated (p < 0.01 and p < 0.05 respectively) with MV in the middle cerebral artery (MCA) according to linear regression analysis (r = 0.78 and 0.59 respectively). All patients, having impaired vasomotor reactivity (VMR) < or = 11% in the anterior cerebral artery (ACA) on the occluded side, had pathological flow pattern in the OA. Patients with greatest difference (delta) between MV in the ACA on the nonoccluded and occluded side had a tendency to anterograde flow (r = 0.56, p < 0.05). Pulsative index (PI) in the ACA on the occluded side was lowest in the category with retrograde flow in the OA (0.67 +/- 0.14) and differed (p < 0.05) from normals and from the category with isoelectric and anterograde flow. Correlation of retrograde flow direction in the OA and baseline MV in the MCA and low PI in the ACA on the occluded side indicates a supplying ophthalmic collateral to the anterior brain circulation. Impaired VMR in the ACA on the occluded side in connection with pathological flow pattern in the OA may reflect an exhaustion of the ACA as a supplying vessel.