FDG-PET/CT findings in systemic mastocytosis: a French multicentre study

INTRODUCTION

Mastocytosis is a clonal haematological disease characterized by uncontrolled proliferation and the activation of mast cells. The value of FDG-PET/CT (FDG-PET) in mastocytosis has yet to be determined.

METHODS

We retrospectively identified patients with an established diagnosis of systemic mastocytosis (SM), according to the WHO criteria, who underwent PET using the French Reference Centre for Mastocytosis database. Semi-quantitative and visual analysis of FDG-PET was performed and compared to the clinico-biological data.

RESULTS

Our cohort included 19 adult patients, median age 65 years [range 58-74], including three with smouldering SM (SSM), three with aggressive SM (ASM), 10 with an associated clonal haematological non-mast-cell lineage disease (SM-AHNMD), and three with mast cell sarcoma (MCS). FDG-PET was performed at the time of the SM diagnosis (15/19), to evaluate lymph node (LN) activity (3/19) or the efficacy of therapy (1/19). FDG uptake was observed in the bone marrow (BM) (9/19, 47%), LN (6/19, 32%), spleen (12/19, 63%), or liver (1/19, 5%). No significant FDG uptake was observed in the SSM and ASM patients. A pathological FDG uptake was observed in the BM of 6/10 patients with SM-AHNMD, appearing as diffuse and homogeneous, and in the LN of 5/10 patients. All 3 MCS patients showed intense and multifocal BM pathological uptake, mimicking metastasis. No correlation was found between the FDG-PET findings and serum tryptase levels, BM mast cell infiltration percentage, and CD30 and CD2 expression by mast cells.

CONCLUSIONS

FDG uptake does not appear to be a sensitive marker of mast cell activation or proliferation because no significant FDG uptake was observed in most common forms of mastocytosis (notably purely aggressive SM). However, pathological FDG uptake was observed in the SM-AHNMD and in MCS cases, suggesting a role of FDG-PET in their early identification and as a tool of therapeutic assessment in this subgroup of patients.

Detection of asymptomatic aortic involvement in ANCA-associated vasculitis using FDG PET/CT

Large vessel involvement in ANCA-associated vasculitis is very rare. We report here on the case of two patients with ANCA-associated vasculitis and asymptomatic aortic arch involvement diagnosed using FDG-PET/CT. Because aortic involvement in ANCA-associated vasculitis is a potentially life-threatening condition, its early detection can be crucial. FDG-PET/CT may also provide new insights into large vessel involvement as part of the spectrum of ANCA-associated vasculitis.

Heart rate variability in rats with chronic hypoxic pulmonary hypertension

The precise role of pulmonary hypertension as a possible factor inducing a decrease in heart rate variability is poorly known. Spectral analysis of heart rate variability (HRV) was carried out in 21 Wistar rats before and after exposure to normoxia (N = 10) or to 3 weeks of hypobaric hypoxia inducing chronic pulmonary hypertension and right ventricular hypertrophy (N= 11). Continuous ECG was recorded in conscious animal at rest. Compared to the control group, rats exposed to hypoxia had a similar heart rate but a lower overall HRV (total power, 27.9 +/- 15.2 vs. 57.6 +/- 24.7 ms2, P < 0.01). Low frequency power (0.25-0.8 Hz) and high frequency power (0.8-3 Hz) were similar in both groups suggesting that HRV was decreased in the very low frequency power (0-0.25 Hz). The effects of atropine and propranolol on heart rate and HRV were similar in rats exposed or not to hypoxia. HRV is decreased in rats with hypoxic induced pulmonary hypertension, mainly in the very low frequency band, suggesting an increase in sympathetic activity. However, this decrease is moderate and the modulation of HRV with pharmacologic autonomic blockade remains similar to that of normal rats.

Mean xenograft survival of 14.6 days in a small group of hDAF-transgenic pig hearts transplanted orthotopically into baboons

INTRODUCTION

In a discordant orthotopic xenotransplantation model (pig-to-baboon) donor pigs expressing human decay accelerating factor (hDAF) as a regulator of complement activity were used to prevent hyperacute xenograft rejection (HXR). We investigated a modified immunosuppressive therapy consisting of ERL080 (Novartis Pharma AG, Base, Switzerland), cyclosporin A (Neoral), steroids, and a cyclophosphamide (CyP) induction protocol with several reduced doses to prevent acute vascular rejection (AVR).

METHODS

Donor hearts were harvested from hDAF-transgenic pigs (18.8 +/- 2.6 kg, Imutran Ltd., a Novartis Pharma AG Company). Four adult baboons (25.6 +/- 2.7 kg) with high titers of xenoreactive antibodies (XAb) served as recipients. Serological and hemodynamic parameters were measured. Finally, myocardial tissue was sampled for histological and immunohistochemical examinations.

RESULTS

In the first baboon, an acute graft failure occurred after 1 hour due to preservation injury. The second succumbed after 11.1 day due to an acute renal failure. The third died after 13.1 days of an ileus. The fourth baboon had continuously excellent cardiac function (mean echocardiographic ejection fraction, 69.2%), but succumbed on day 20 due to anemia. Corrected mean xenograft survival (excluding the first baboon because of a technical failure) was 14.6 +/- 2.6 days. XAb decreased after day 3 to constantly low levels (<1:64 titer) after CyP induction. White blood cell count decreased from 10.3 +/- 0.8 to 0.9 +/- 0.3 G/L after day 3. Macroscopically and histologically no typical signs of HXR or severe AVR could be detected.

CONCLUSIONS

These results confirm that hDAF transgen blocks HXR in this life-supporting model. AVR was prevented by using a modified quadruple immunosuppressive drug combination (Neoral, ERL080, steroids, and several small single doses of CyP). An optimum "fine-tuning" of immunosuppression is required to achieve the best risk-benefit ratio.

Combination of hDAF-transgenic pig hearts and immunoadsorption in heterotopic xenotransplantation of immunosuppressed baboons

INTRODUCTION

Hyperacute xenograft rejection (HXR) and acute vascular rejection (AVR) after xenotransplantation are triggered by xenoreactive antibodies (XAb) and an activated complement cascade. In a heterotopic (abdominal) xenotransplantation model we combined immunoadsorption (IA, Ig-Therasorb column) and a quadruple immunosuppressive drug therapy in recipient baboons with donor pig hearts transgenic for human decay accelerating factor (hDAF).

METHODS

According to XAb titers between 6 and 14 cycles of IA were performed preoperatively in 4 recipient baboons (18.6 +/- 2.5 kg). Hearts of hDAF-transgenic donor pigs (6.1 +/- 1.1 kg, Imutran Ltd., a Novartis Pharma AG Company, Basel, Switzerland) were heterotopically transplanted using the abdominal technique in baboons. Immunosuppression consisted of cyclophosphamide (CyP) induction therapy, ERL080 (Novartis Pharma AG), cyclosporin A (CyA, Neoral), and steroids. Blood levels of mycophenolate, CyA, immunoglobulins (Ig), anti-pig-antibodies, complement factors, and cardiac enzymes were determined. Abdominal electrocardiography (ECG), echocardiography, and palpation were used for monitoring of the pig hearts. Myocardial tissue specimens were examined using immunohistochemistry, light microscope (LM), and electron microscope (EM).

RESULTS

Ten cycles of IA alone removed 78% of XAb and accordingly IgM, IgG, IgA, complement C3, and C4. None of the xenografts was hyperacutely rejected, but xenograft failure occurred after 5.0 +/- 1.3 days (range, 2.4-8.0 days) because of an AVR associated with a rapid XAb increase within 24 hours. White blood cell count (10.3 +/- 2.2 G/L) showed a maximum of 13.1 +/- 2.1 (day 1) and constant levels (1.4 +/- 0.3-2.1 +/- 1.3 G/L) between day 3 and 6. Histology (LM/EM) showed massive hemorrhage, necrosis, and vascular thrombi as signs of AVR.

CONCLUSION

Although HXR was prevented by using IA and hDAF-transgenic donor hearts, AVR was not avoided due to insufficient immunosuppressive regimen used and a missed postoperative IA treatment as a result of an inefficient control of XAb production.

[Contribution of lymphoscintigraphy in the exploration of lymphedema in children]

OBJECTIVES

The objectives of this work were a) to assess the feasibility of lymphoscintigraphy in very young children, and b) to assess its usefulness in understanding the underlying pathophysiology.

PATIENTS AND METHODS

Forty-one children (age range 3 months-16 years) with primary lymphedema of the lower and/or upper limbs underwent lymphosinctigraphy using 99mTC-labeled colloid (Nanocis or Nanocol) injected subcutaneous at the foot and/or hand level. Recording time, which depended on the child's age, included at least static images during the thirty minutes following injection and four hours later.

RESULTS

Abnormal activity of the lymph collectors, nodes, and interstitial space were analyzed according to age (> or < 2 years). Abnormal findings were classed as simple hypoplasia (n=18) or other type of lymph disease: diffuse lymphatic dysplasia (n=6), mixed vascular dysmorphism (n=5), amniotic bride disease (n=1), and hypoplasia revealed by occurrence of a minor factor (n=11). These observations demonstrate the role of lymphoscintigraphy in the diagnosis and prognostic evaluation of lymphedema in children.

CONCLUSION

Lymphoscintigraphy is a useful technique for very young children with lymphedema providing further information contributing to overall exploration.

The value of immunoscintigraphy in the detection of recurrent colorectal cancer

The aim of this prospective study was to determine whether anti-carcinoembryonic antigen (anti-CEA) scintigraphy is a useful additional technique in the diagnosis recurrence of colorectal cancer. Forty patients with suspected recurrence of colorectal cancer, underwent immunoscintigraphy (IS) and helical computed tomography (CT) in the 2 weeks before surgery. Surgical findings were used to evaluate the performance of the imaging techniques. Suspected areas on IS and CT were systematically explored. Helical CT was found to be superior to IS for the liver, the sensitivity and specificity of CT being 100% and 90%, respectively, vs 53% and 100% for IS. However, IS was better than CT for the detection of extra-hepatic abdominal recurrence: sensitivity and specificity of IS were 100 and 82% respectively vs 33 and 82% for CT. Seven cases of peritoneal carcinomatosis were overlooked by helical CT. Our results indicate that IS improves detection of extra-hepatic abdominal recurrence of colorectal cancer. Immunoscintigraphy is valuable as a guide to the treatment strategy and operative procedures.

Prevention of hyperacute xenograft rejection in orthotopic xenotransplantation of pig hearts into baboons using immunoadsorption of antibodies and complement factors

To prevent hyperacute xenograft rejection (HXR) caused by preformed natural antibodies (XNAb) after orthotopic heart xenotransplantation (oXHTx) of landrace pig hearts into baboons, we used immunoadsorption of immunoglobulins IgG, IgM and IgA and complement with the reusable Ig-Therasorb column. In addition to functional data, tissue was sampled for histological, immunohistochemical and electron microscopical analysis. We performed three oXHTx of landrace pig hearts to baboons using extracorporeal circulation (ECC) connected to the immunoadsorption unit. Intraoperative treatment consisted of four cycles of immunoabsorption (IA). One oXHTx of a baboon without IA served as a control. A mismatch of donor and recipient heart size was prevented by selecting a 30-40% lower body weight of donor pigs than recipients. Four cycles of IA removed more than 80% of IgG, IgM and IgA, 86% of antipig antibodies and 66% of complement factors C3 and C4 from plasma. The graft of the control animal failed after 29 min. Orthotopic xenotransplantation with IA was selectively terminated after 100 min, 11 h and 21 h, respectively without any histological signs of HXR in light and electron microscopy. After weaning off from ECC these donor xenografts showed sufficient function with normal ECG and excellent cardiac output in echocardiography and invasive measurement (1.93 +/- 0.035 l/min). The myocardium of the control xenograft demonstrated more deposits of Ig and complement components (C3, C4) than in the IA group. Baboons survive HXR after orthotopic pig heart xenotransplantation due to antibody depletion by reusable Ig-Therasorb column treatment. Long-term survival in an orthotopic baboon xenotransplantation model after IA, especially in combination with transgenic pig organs, could be a reliable preclinical trial for future clinical xenotransplantation programs.

Technetium-99m ECD single photon emission computed tomography in brain trauma: comparison of early scintigraphic findings with long-term neuropsychological outcome

OBJECTIVE

The aim of this study was to assess the prognostic value of early brain scintigraphy in head injury in relation to long-term neuropsychological behavior. Twenty-four patients underwent technetium-99m (Tc-99m) ethyl cysteinate dimer single photon emission computed tomography (SPECT) within 1 month of the trauma. Scintigraphic abnormalities were evaluated both visually and semiquantitatively using the brain-to-cerebellum ratio method. The clinical neuropsychological investigation was conducted to evaluate abnormalities related to motor deficit, frontal behavior, and memory and language disorders. All patients had abnormalities on SPECT scan. One year after trauma, 14 patients (58%) had neuropsychological sequelae. The brain-to-cerebellum ratios in the left basal ganglia and brain stem were significantly decreased in patients with memory disorders (P = .03 and P = .02, respectively). Moreover, SPECT visual analysis indicated that low uptake in the basal ganglia, thalamus, and brain stem was associated with subsequent motor deficit, frontal behavior, and language and memory disorders. The authors conclude that brain SPECT can be valuable in predicting the neuropsychological behavior of survivors of severe head injury.

Localization of the ventricular preexcitation site in Wolff-Parkinson-White syndrome with Doppler tissue imaging

PURPOSE

The objective of this study was to evaluate the ability of Doppler tissue imaging (DTI) to localize the ventricular emergence site of accessory atrioventricular pathways (Wolff-Parkinson-White syndrome).

METHODS

Thirty-three patients were studied prospectively by Doppler tissue imaging (128XP and Sequoia 256 echocardiographic systems; Acuson, Mountain View, Calif) before investigation of Wolff-Parkinson-White syndrome and after radiofrequency ablation of the accessory pathways. The normal appearance of the ventricular contractions was defined in a group of 10 control subjects. The preexcitation zone was determined as a zone of maximum acceleration in "DTI acceleration mode" or as a coded contraction zone in "DTI velocity mode," at the time of the delta wave or before the onset of the QRS complex.

RESULTS

The earliest ventricular activation site was correctly localized for 12 of the 15 left-sided pathways (8 anterior or anterolateral, 2 lateral or posterolateral, 2 inferior). When wall motion abnormalities were detected in the left ventricle by DTI, the left-sided localization was confirmed by electrophysiologic exploration. For the right-sided pathways, the localization was correct in only 4 of 11 cases (3 posteroseptal and 1 anterolateral). After effective ablation in all patients, the abnormalities corresponding to the electrophysiologic data disappeared totally in only 11 of 16 patients.

CONCLUSION

In the presence of Wolff-Parkinson-White syndrome, DTI localizes contraction abnormalities associated with early activation of a part of the ventricle. However, the interpretation of the images remains difficult because the normal coding of the contraction of the ventricular walls depends on the incidence for which they are investigated. This noninvasive examination seems to be an effective tool for localizing the left-sided accessory pathways of the left ventricle, in particular in the anterior, anterolateral, or inferior walls.

Fourier phase analysis of SPECT equilibrium radionuclide angiography in symptomatic patients with mitral valve prolapse without significant mitral regurgitation: assessment of biventricular functional abnormalities suggesting a cardiomyopathy

BACKGROUND

Ventricular premature beats are common in patients with mitral valve prolapse (MVP). The purpose of this study was to determine whether symptomatic patients with MVP had certain functional characteristics and if ventricular arrhythmia (VA) could be explained by functional extravalvular abnormalities. Single photon emission computed tomography equilibrium radionuclide angiography with Fourier phase analysis was preferred to the planar radionuclide method. Only patients without significant mitral regurgitation were studied.

METHODS AND RESULTS

A total of 23 symptomatic patients with MVP (13 men, 10 women, mean age, 47+/-14 years) without mitral regurgitation underwent single photon emission computed tomography equilibrium radionuclide angiography. Symptoms were present in 20 patients, and VA was present in 14 patients. Ejection fraction, regional wall motion, and Fourier phase analysis were examined in both ventricles and compared with results for normal subjects. Ventricular abnormalities were observed in 20 (87%) patients: decreased left ventricular and right ventricular ejection fractions, increased standard deviations of the mean phase and focal wall motion, and/or delayed phase abnormalities. Abnormalities were less frequent but more marked in the right ventricular free wall, the infundibulum, or the septum compared with left ventricular delayed abnormalities, which were more frequent but limited. In 12 of 14 patients with VA, phase-delayed areas were observed in the ventricle where the origin of ventricular premature beats was suspected on the basis of their electrocardiographic morphologic features. A relation was found between late potentials and delayed-phase areas (right ventricle or septum) and left bundle branch block morphologic features of VA.

CONCLUSIONS

Symptomatic patients with MVP frequently have ventricular dysfunction in 1 or both ventricles, sometimes limited but more marked in the presence of severe VA even without significant mitral regurgitation, suggesting structural modification. The use of a sensitive, accurate, and 3-dimensional method such as single photon emission computed tomography equilibrium radionuclide angiography may be of interest for a noninvasive investigation, especially in young symptomatic patients with MVP and VA.

[Diagnostic value of stress echocardiography under dobutamine and myocardial scintigraphy for restenosis at 6 months after angioplasty of the left anterior descending artery]

This study compared prospectively the diagnostic value of dobutamine echocardiography and exercise myocardial scintigraphy for restenosis at 6 months after angioplasty of the left anterior descending artery. Forty-one patients aged 58 +/- 10 years, admitted to hospital for myocardium infarction (N = 22) or unstable angina (N = 19), with single vessel disease, were treated by angioplasty of one lesion of the left anterior descending artery after initial evaluation of the left ventricular ejection fraction by echocardiography. At 6 months, left ventricular function was reassessed by echocardiography, dobutamine echocardiography and exercise myocardial scintigraphy (Thallium 201) performed without treatment. Coronary angiography was performed at the same time and showed 8 restenosis (19.5%). Overall, in this series, dobutamine echo and scintigraphy had respectively a sensitivity of 37.5% and 75%, and a specificity of 97% and 70% (p < 0.02). Nine patients had left ventricular dysfunction unchanged compared with the initial measurement without viability in the territory of the left anterior descending artery with low dose dobutamine (group 1); thirty-two patients had improved or normal left ventricular ejection fraction with myocardial viability (group 2). In group 1, no cases of restenosis were detected by dobutamine echocardiography but_of them had myocardial scintigraphic evidence of ischaemia. In group 2, the sensitivity of the two techniques was comparable but dobutamine echo was more specific than scintigraphy (96 versus 75%, p = 0.03). In conclusion, dobutamine echocardiography may be indicated in the diagnosis of restenosis of the left anterior descending artery and in cases of viability in its territory. In its absence, myocardial scintigraphy seems to be preferable.

Doppler monitoring of the vascular resistance in the lower limbs during dipyridamole test in preparation for myocardial tomoscintigraphy

OBJECTIVE

the aim of this work was to quantify the intensity of the vasodilation induced by dipyridamole used to simulate a stress test during a myocardial tomoscintigraphy.

METHODS

Doppler measurements of the femoral artery and the thoracic aorta were made on 26 patients (11 men, 15 women), using transducers attached to the skin, measurements being performed every 2 min during the 10 min of the stress test. The following parameters were measured: (a) the vascular resistance index of the lower limbs defined as R(fa)=D/S with S and D, respectively, the maximum amplitude of the systolic wave and the maximum amplitude of the diastolic reflux measured on the Doppler femoral spectrogram; (b) the aortic and femoral blood flows obtained from the mean velocity on the Doppler spectrogram.

RESULTS

14 of the 26 patients (54%) showed a significant vasodilation (i.e. a decrease of R(fa) of more than 10%). Eighty-seven percent of the patients with a positive myocardial scintigraphy showed a vasodilation. Sixty-six percent of patients who had prior vasodilator treatment showed no vasodilation. A slight decrease in blood pressure was observed for vasodilated patients but also for non-vasodilated patients. The aortic flow increased slightly for all patients.

CONCLUSIONS

Doppler monitoring of femoral vascular resistance is a useful method for quantifying the dipyridamole-induced vasodilation, and hence the stress level upon which the diagnostic efficiency of myocardial scintigraphy is depending. Our study demonstrates that testing with dipyridamole was inconclusive in 66% of patients who had already vasodilator treatment.

Evaluation of left ventricular systolic function by 3D echocardiography: a comparative study with X-ray angiography and radionuclide angiography

OBJECTIVE

the aim of this study was to evaluate left ventricular systolic function by 3D ultrasound as compared to with radionuclide and X-ray angiographies.

METHODS

one hundred and four patients were examinated by 3D ultrasound (3D-US) but only 72 examinations were successful. Thirty patients were investigated by 3D-US, M-mode US or bidimensional (2D) US, and X-ray angiography (group I) and 42 patients were investigated by 3D-US, M-mode, or 2D, and radionuclide angiography (group II).

RESULTS

the correlation between ejection fraction (EF) evaluated by 3D-US and reference methods was found to be good and similar for the two groups (r=0.75; P<10(-4) for group I and r=0.76; P<10(-4) for group II). The correlation between EF calculated by conventional 2D-US and by reference methods was lower (r=0.60; P=0.04 for group I and r=0.54; P=0.001 for group II). The correlation between EF evaluated by 3D- and 2D-US was modest (r=0. 55; P=0.001 for the whole group). The correlation between 3D-US left ventricle end-diastolic volume (EDV) and end-systolic volume (ESV) and those evaluated by X-ray angiography was also modest (r=0.33; NS for EDV and r=0.60; P<10(-4) for ESV). The correlations between EDV and ESV in 3D-US, and those evaluated from radionuclide angiography were fairly good and in the same range (r=0.76; P<10(-4) and r=0.87; P<10(-4)).

CONCLUSION

the 3D-US system using a rotating probe in an apical view is valuable for evaluation of left ventricular systolic function.

Real-time 3-D ultrasound acquisition and display for cardiac volume and ejection fraction evaluation

The objective of this study was to test if three-dimensional (3-D) ultrasound (US) provides accurate determination of the cardiac volumes and ejection fraction. The 3-D device (Model 1-Volumetrics, ) is a 3-D acquisition system using a 2-Mhz matrix probe that insonates the whole cardiac volume in a 4-chamber view and collects the entire backscattered US echoes from this volume within one cardiac cycle. The complete 3-D US information stored in the memory can then be cut into 2-D views of any arbitrary orientation. For volume determination, the best 4-chamber view was selected into the memory, then 6 transverse views were displayed at different depths along the ventricle long axis, and the contour of the ventricle was drawn on each of these views. The left ventricle volume in diastole (LVDV) and the ejection fraction (EF) obtained by 3-D US were compared with those from x-ray and isotopic angiographies, and 2-D echo-time motion (2-D Echo-TM). The variations in stroke volume (SV) during a stand test, measured by 3-D US, and aortic Doppler were compared. The correlation between EF evaluated from 3-D US and x-ray or isotopic angiographies was found to be good (r = 0.80 p < 0.001; r = 0.86 p < 0.001), but lower with 2-D Echo-TM (r = 0.59 p < 0.001). For LVDV, the correlation was acceptable with x-ray angiography (r = 0.75 p < 0.001), but much lower with isotopic angiography and 2-D Echo-TM (r = 0.47 p < 0.001; r = 0.55 p < 0.001). A good correlation was also found between the SV changes measured by 3-D US and aortic Doppler (r = 0.79 p < 0.001).

IG-therasorb immunoapheresis in orthotopic xenotransplantation of baboons with landrace pig hearts

BACKGROUND

The major problem of xenotransplantation is, that hyperacute xenograft rejection (HXR) causes graft failure within minutes or a few hours because of natural antibodies and activation of the complement system. As a preclinical model we transplanted pig hearts orthotopically into baboons. To prevent HXR after orthotopic xenotransplantation (oXHTx), the immunoglobulins (Ig) and natural antibodies were adsorbed to reusable Ig-Therasorb immunoadsorption (IA) columns.

METHODS

We performed three oXHTx of landrace pig hearts into baboons (19+/-6.8 kg), using extracorporeal circulation (ECC) connected to the IA unit. After separating the recipient's blood into plasma and cellular fraction by a plasma filter, plasma flow was directed to the Ig-Therasorb column coated with polyclonal sheep-antibodies against human IgG, IgM, and IgA. Intraoperative treatment consisted of 4 cycles of IA. For a control, we transplanted one pig heart into a baboon (16.9 kg) without applying IA. Perioperatively, serum concentrations of Ig, anti-pig-antibodies, complement and cardiac enzymes were determined. Tissue samples of myocardium were collected at the end of the study for immunohistochemical examinations, light microscopic examination (LM) and electron microscopic examination (EM). For cardiac monitoring after oXHTx, we used ECG, echocardiography, and invasive measurement of cardiac output. To prevent a mismatch of donor and recipient heart size, the donor pig had a 30-40% lower body weight than the recipient baboon.

RESULTS

Four cycles of IA removed >80% of IgG, IgM, and IgA from plasma. The graft of the control animal failed after 29 min. The first oXHTx with IA was intentionally terminated after 100 min, the second oXHTx after 11 hr and the third oXHTx after 21 hr. All xenografts showed no histological signs of HXR. After weaning off ECC, these donor hearts worked in sinus rhythm without electrocardiographic ST-segment elevation. An excellent cardiac output was measured by echocardiography and thermodilution (2 L/min). Serological parameters indicating cardiac damage were significantly lower after IA if compared with the control experiment. Macroscopically, the xenograft of the control animal showed massive hemorrhage in comparison with the almost inconspicuous grafts after IA. The myocardium of the IA group demonstrated fewer deposits of Ig and complement components compared with the control animal.

CONCLUSION

Baboons do not hyperacutely reject a porcine xenograft after antibody depletion by the Ig-Therasorb column. In our experiment only 4 cycles of immunoapheresis effectively prevented HXR after oXHTx of baboons. The Ig-Therasorb column is a reusable device, which can be handled easily in combination with the ECC. IA must be tested in oXHTx longterm survival experiments, especially in combination with transgenic pig organs, which could be a reliable preclinical approach for future clinical xenotransplantation.

Initial color Doppler findings in retinal vein occlusion

PURPOSE

We assessed early hemodynamic characteristics of various types of retinal vein occlusion using color Doppler imaging and spectral analysis.

METHODS

We measured the maximum systolic and diastolic blood flow velocities and the resistance index (RI) in the central retinal artery and the maximum and minimum blood flow velocities in the central retinal vein of affected eyes and contralateral unaffected eyes in 102 adults (63 men and 39 women; mean age, 61 +/- 14.6 years) who presented with retinal vein occlusion. Sixty-three control subjects (27 men and 36 women; mean age, 50 +/- 22.1 years) were also investigated.

RESULTS

No significant differences in hemodynamic characteristics were found between the control subjects' eyes and the patients' unaffected eyes. In the 18 cases of ischemic central retinal vein occlusion, the mean diastolic arterial flow velocity (p = 0.005) and venous flow velocity (p < 0.04) were lower and the mean RI was higher (p = 0. 0002) in the affected eyes than in the unaffected contralateral eyes. In the 51 cases of nonischemic central retinal vein occlusion, the mean diastolic arterial flow velocity (p < 0.0001) and venous flow velocity (p < 0.0001) also were lower and the mean RI (p < 0.0001) was higher in the affected eyes than in the unaffected contralateral eyes. These variables were different in the ischemic versus nonischemic types of central retinal vein occlusion. In the 33 cases of branch retinal vein occlusion, no significant differences were observed in arterial or venous blood flow velocities in the affected versus unaffected eyes. The mean RI in the affected eyes was significantly higher (p = 0.009) in patients with central versus branch retinal vein occlusion.

CONCLUSIONS

These results suggest that previous arterial disorders were not involved in the pathogenesis of central retinal vein occlusion in these patients. The findings also support the value of Doppler imaging and spectral analysis in the diagnosis and evaluation of retinal vein occlusion and confirm the involvement of arterial flow in venous occlusion.

[Comparative study of post-infarction myocardial viability after fibrinolysis by stress tomoscintigraphy and echography: can viability be detected without ischemia?]

The objectives of this prospective study was to define the comparative ability of stress myocardial scintigraphy and dobutamine stress echocardiography to demonstrate post-MI myocardial viability, assessed on the functional recovery in terms of improvement of global and segmental kinetics by cardiac gamma-angiography after revascularization. 18 patients (11 anterior MI, 7 lateral or inferior MI) and 162 segments were analysed semiquantitatively. All patients with persistent significant stenosis underwent secondary revascularization of the artery responsible for myocardial infarction. The prevalence of viability was high, as only 34% of segments initially presented a segmental kinetic abnormality and contraction was improved at 6 months in 54% of cases. Stress scintigraphy and dobutamine echocardiography detected viability with a sensitivity of 96% and 70%, a specificity of 88% and 82%, a positive predictive value of 89% and 77% and a negative predictive value of 95% and 76%, respectively. Only the wall score index with low-dose dobutamine was correlated with the ejection fraction at 6 months. Stress echocardiography is a more reliable predictor of the degree of functional recovery after revascularization. Scintigraphy visualizes much more extensive abnormalities than echocardiography. This often corresponds to ischaemic territories with normal contraction under baseline conditions and low doses of dobutamine. It therefore seems preferable both examinations for optimal assessment of thrombolized patients following myocardial infarction.

Clinical use of ultrasound tissue harmonic imaging

The recent introduction of tissue harmonic imaging could resolve the problems related to ultrasound in technically difficult patients by providing a marked improvement in image quality. Tissue harmonics are generated during the transmit phase of the pulse-echo cycle, that is, while the transmitted pulse propagates through tissue. Tissue harmonic images are formed by utilizing the harmonic signals that are generated by tissue and by filtering out the fundamental echo signals that are generated by the transmitted acoustic energy. To achieve this, two processes could be used; one by using filters for fundamental and harmonic imaging and the second using two simultaneous pulses with a 180 degrees difference in phase. The introduction of harmonics allows increased penetration without a loss of detail, by obtaining a clearer image at depth with significantly less compromise to the image quality caused by the use of lower frequencies. This imaging mode could be used in different organs with a heightening of low-contrast lesions through artefact reduction, as well as by the induced greater intrinsic contrast sensitivity of the harmonic imaging mode.

Diagnosis of arrhythmogenic right ventricular cardiomyopathy by fourier analysis of gated blood pool single-photon emission tomography

To evaluate the diagnostic performance of Fourier phase analysis of gated blood pool single-photon emission computed tomography (GBP SPECT) in arrhythmogenic right ventricular (RV) cardiomyopathy, 18 patients with confirmed arrhythmogenic RV cardiomyopathy underwent GBP SPECT and x-ray cineangiography. Results were compared with data obtained with GBP SPECT in 10 control subjects. This 3-dimensional method demonstrated good correlation with cineangiography for measurements of RV enlargement and extent of the disease; RV and left ventricular segments were analyzed with the same accuracy. Tomographic abnormalities were significant decreased RV ejection fraction, RV dilatation, nonsynchronized contraction of the ventricles, increased RV contraction dispersion, presence of segmental RV wall motion disorders and/or phase delays, and occasionally regional left ventricular abnormalities. RV-delayed phase areas were always present in our population. A scoring system with RV criteria was proposed to diagnose RV disease. Because Fourier analysis of GBP SPECT provides ventricular morphologic information for the right ventricle with the same accuracy as for the left ventricle, it may replace planar radionuclide studies. Therefore, this method is helpful in patients with a strong clinical suspicion of arrhythmogenic RV cardiomyopathy, and should be used as a screening method before right ventriculography.

[Value of tomoscintigraphy with Fourier analysis in the diagnosis of arrhythmogenic right ventricular cardiomyopathy]

ECG gated blood pool tomography has been performed in sixteen patients with right ventricular arrhythmias in whom the diagnosis of arrhythmogenic right ventricular cardiomyopathy was made based on the finding of abnormalities on contrast angiography. They were compared both to control subjects and to patients with primary dilated cardiomyopathy. Thick slices of ventricles were obtained throughout the cardiac cycle in three orthogonal planes: horizontal long axis and short axis thick slices for analysis of right and left ventricular regional wall motion abnormalities and analysis of the spread of the contraction by means of Fourier phase imaging, vertical long axis slices (one for each ventricle) for ejection fractions, because of easy and reproducible determination of valvular planes and analysis of all right ventricular segments, especially the pulmonary infundibulum. Five typical right ventricular abnormalities were seen: decreased ejection fraction (32 +/- 15% vs 55 +/- 3% in control; p < 0.001), increased diameter (ratio of right to left diameters = 1.2 +/- 0.3 vs 0.9 +/- 0.1; p < 0.01), global delayed contraction versus that of the left ventricle (22 +/- 20 degrees vs -2 +/- 6%; p < 0.01), increased dispersion of contraction (32 +/- 16 degrees vs 13 +/- 4 degrees; p < 0.01) and presence of segments with decreased and/or delayed contraction. Right ventricular disease was observed in all the patients: localized form (56%), diffused form (44%). This method provides accurate functional data for diagnosis and follow-up of patients. In future, this wall motion evaluation method may replace planar nuclear angiography as myocardial SPECT have replaced myocardial planar scintigraphy.

Mitral annuloplasty with a flexible linear reducer

Although the ideal technique is still controversial, mitral valve reconstruction for mitral insufficiency usually includes an annuloplasty. From August 1985 to June 1993, 126 cases of pure, acquired mitral insufficiency were repaired by means of a posterior annuloplasty. Whatever the etiology, all types of mitral insufficiency allowing a mitral reconstruction were included. The annuloplasty, performed with a flexible linear reducer, was associated with valvular (62%) and subvalvular (11%) repairs. An associated surgical procedure was necessary in 62% of the patients. Operative mortality was 2.4%, and follow-up (mean 29 months) was complete for all survivors. Five-year survival was 90%. Five-year complication-free rate for emboli was 91%. Only one patient at 12 months underwent reoperation to treat recurrent mitral insufficiency. Ninety-seven patients were in New York Heart Association Class I or II. Follow-up echocardiographic studies on 75% of eligible patients showed a free rate for significant regurgitation of 99%. Mean valve area was estimated at 2.88 +/- 0.85 cm2. These findings suggest that the flexible linear reducer seems to be a reliable device and a valid alternative for annuloplasty.