Andreas J. Morguet

Immunoscintigraphy using technetium-99m-labeled anti-NCA-95 antigranulocyte antibodies as an adjunct to echocardiography in subacute infective endocarditis

OBJECTIVESnThis study was performed to assess the clinical value of immunoscintigraphy in subacute infective endocarditis.nnnBACKGROUNDnRadiolabeled granulocytes can reveal inflammatory lesions.nnnMETHODSnUsing technetium-99m-labeled anti-NCA-95 anti-granulocyte antibodies, planar scintigraphy and single-photon emission computed tomography of the thorax were performed in 72 consecutive patients with suspected endocarditis. Each patient also underwent transthoracic and, if findings were negative, transesophageal echocardiography.nnnRESULTSnThirty-three patients were found to have endocarditis on the basis of clinical criteria (surgical confirmation in 17 patients), and the remaining 39 served as control subjects. Initial scintigraphy was true positive in 26 patients (sensitivity 79%) and false positive in 7 (specificity 82%). Echocardiography was true positive in 29 patients (sensitivity 88%) and false positive in 1 (specificity 97%). Scintigraphy was positive in the four patients with false negative echocardiography, and echocardiography was positive in the seven patients with false negative scintigraphy. Thus, the combination of scintigraphy and echocardiography yielded a sensitivity of 100% and a specificity of 82%. In 10 of the 11 patients with two to three follow-up studies, scintigraphy became negative parallel to clinical improvement, indicating decreasing floridity of the inflammatory process.nnnCONCLUSIONSnImmunoscintigraphy in patients with subacute infective endocarditis provides valuable diagnostic information in equivocal echocardiographic findings and may be used to monitor antibiotic therapy.

Radioimmunoimaging of subacute infective endocarditis using a technetium-99m monoclonal granulocyte-specific antibody

Immunoscintigraphy with a technetium-99m murine monoclonal IgG1 antibody directed against non-specific cross-reacting antigen (NCA-95) and carcinoembryonic antigen was performed with 20 patients with suspected subacute infective endocarditis (SIE) and 6 controls with suspected inflammatory/infectious disease elsewhere in the body. Immunoscintigraphy and echocardiography localised SIE in 11 of 15 patients in whom the disease could be confirmed. In 4 patients with validated SIE, the immunoscan was abnormal, and the echocardiogram was normal. In another 4 patients, the result was exactly the opposite. These findings suggest that the combination of immunoscintigraphy and echocardiography improves diagnostic efficacy in patients with suspected SIE.

Giant Cell Myocarditis due to Coxsackie B2 Virus Infection

Giant cell myocarditis is a rare disorder characterized by the histologic hallmark of diffuse inflammatory infiltrates with the appearance of multinucleated giant cells. We report on a 52-year-old man who died of rapidly progressive cardiogenic shock due to giant cell myocarditis. Serological and immunoblotting techniques revealed a myocardial infection with coxsackie B2 virus, suggesting a viral etiology of this disease. Here we present evidence for the involvement of autoimmune responses to the myocardium as numerous cardiomyocytes exhibited deposits of cell-adherent immunoglobulins. Although other causative factors may initiate giant cell myocarditis as well, our case suggests coxsackie B2 virus as one etiologic agent capable of triggering autoimmune reactions to altered heart tissue.

Scintigraphic detection of inflammatory heart disease

Inflammatory diseases of the heart encompass myocarditis, endocarditis and pericarditis. This paper discusses the diagnostic potential of scintigraphy in these entities. In myocarditis, indium-111 antimyosin Fab imaging can visualize active myocyte damage and thus contribute substantially to the diagnosis. Antimyosin uptake is also seen in a large subset of patients with dilated cardiomyopathy, indicating ongoing myocyte injury in these cases. In endocarditis, immunoscintigraphy using monoclonal technetium-99m-labelled antigranulocyte antibodies provides useful diagnostic information in patients with equivocal echocardiographic findings. Immunoscintigraphy seems to indicate the floridity of the inflammatory process in endocarditis and may be used to monitor antibiotic therapy. In pericarditis, the clinical value of scintigraphy has not been convincingly demonstrated.

Morphology of chronic coronary occlusions and response to interventional therapy - a study by intracoronary ultrasound

Objectives. Balloon angioplasty of chronic coronary occlusions has a low procedural success and a high recurrence rate. Better tomographic insights into the lesion morphology may improve the interventional strategy and results. Methods. Intracoronary ultrasound was used during the recanalizaton procedure of 45 chronic coronary occlusions (2 weeks to 14 months; average 3.4 months) to determine the lesion morphology and to assess the angioplasty result. The luminal area and the plaque burden were measured proximal and distal to the occlusion, and within the occlusion. The ultrasonographic characteristics of the occlusive lesions were compared to 45 nonocclusive lesions of age-matched patients with stable angina pectoris. Results. Occlusive lesions were more often echodense as compared to nonocclusive lesions (35% vs. 20% p=0.10). In chronic occlusions a multi- layered plaque morphology was observed in 22%, and this morphology was not found in nonocclusive lesions. Angiographic characteristics were not related to the ultrasonographic morphology of the lesion. Despite similar vessel areas in occlusive and nonocclusive lesions, the balloon size selected according to the angiographic image was underestimated in occlusive lesions. Based on the quantitative ultrasound measurement the balloon size was increased from 2.6±0.3 mm to 3.3±0.5 mm in 53% of the lesions. This resulted in an increase of the luminal area from 3.51±0.92 to 5.08±1.43 mm2 (p<0.001). The acute recoil after balloon angioplasty was similar (34±18%) in hypodense and echodense plaques, but was significantly higher in lesions with a multi-layered plaque morphology (49±22%; p<0.05). In 19 patients with severe dissections or extreme acute recoil (residual stenosis>50%) the use of a stent increased the luminal area from 3.94±0.81 to 7.51±1.71 mm2 (p<0.001). Conclusion. Intracoronary ultrasound demonstrated a multi-layered plaque morphology in one fourth of the chronic occlusions. This type of plaque was associated with a significant acute recoil. The presence of diffuse atherosclerosis in neighbouring segments of chronic coronary occlusions leads to underestimation of the balloon size. Quantitative assessment by intracoronary ultrasound helped to optimize the balloon size leading to a significant luminal area gain. The detection of excessive acute recoil should be considered an indication for stent deployment.

Excimer-laser-induced fluorescence spectroscopy of human arteries during laser ablation

The autofluorescence of human arterial tissue with varying degrees of atherosclerosis was studied in vitro to develop a diagnostic tool for tissue differentiation simultaneously to tissue ablation induced by a XeCl-excimer laser (wavelength 308 nm). Healthy vessel walls and artery segments containing lipid-rich or calcified areas were investigated in air, saline solution (0.9 NaCl), and in blood. The fluorescence spectra in the wavelength range from 320 nm to 650 nm were recorded with an optical multichannel analyzer, and they allowed for a clear discrimination between plaque and healthy vessel wall even in blood. For each single laser shot with an energy density of about 4-5 J/cm2, well above the ablation threshold, a complete spectrum was recorded. The fluorescence spectra were analyzed in terms of their contributions from normal arterial tissue, lipid-rich and calcified plaques. The results clearly show the feasibility of controlling the ablation process by fluorescence spectroscopy in order to avoid vessel-wall perforation which is one of the main drawbacks in laser angioplasty.

Experimental and clinical evaluation of a spectroscopy system for fluorescence-guided excimer laser angioplasty

This study evaluated a single-laser approach for simultaneous ablation and fluorescence excitation for spectroscopic guidance of laser angioplasty. A spectroscopy system was developed and coupled to a clinical XeCl excimer laser. Ablation of 162 human aortic samples in saline and blood with 45 mJ/mm2 per pulse yielded 676 fluorescence spectra validated histologically. Five types of spectra could be differentiated: atheroma, fibrous plaque, calcified lesion in saline, normal media and calcified lesion in blood. Discriminant analysis prospectively classified 576 validation spectra with a sensitivity between 83.5 and 100 percent and a specificity between 96.8 and 100 percent. Subsequently, the equipment was used in 16 patients for angioplasty of 18 coronary stenoses applying 500 to 1725 pulses with 45 to 60 mJ/mm2 under saline flushing. A total of 783 spectra were recorded and validated by intracoronary ultrasound. Except for the media spectrum, all types of spectra were observed in vivo, too. The predominant sonographic category also prevailed in spectroscopy. In conclusion, using an excimer laser for angioplasty allows combining ablation and fluorescence excitation without a diagnostic laser. Principal types of atherosclerotic lesions and the media can be differentiated spectroscopically with this approach.