Digital radiofrequency echocardiography in the detection of myocardial contrast following intravenous administration of Albunex.

Conventional contrast echo techniques have proved inadequate for the detection of myocardial perfusion using intravenously injected echo contrast agents because of the limitations and relative insensitivity of standard echocardiographic equipment. In order to avoid these problems, we have obtained pure digital radiofrequency ultrasound data from the left ventricle and myocardium during i.v. contrast myocardial perfusion echo studies. In 30 patients, following coronary arteriography, i.v. injections of the echo contrast agent Albunex (sonicated human serum albumin) in two doses of 0.08 and 0.22 ml.kg-1 were administered during digital radiofrequency echocardiography sampling of data from the myocardium and left ventricular cavity. Analysis of mean integrated backscatter (MIB, a measure of the total ultrasound energy) was performed before, during and after Albunex injection. The data were also analysed for a shift in frequency spectrum which could be caused by resonance of the Albunex contrast microspheres in the heart, a phenomenon which has been previously demonstrated in vitro. Digital radiofrequency ultrasound data were successfully obtained and analysed in 23 patients. In 31 segments where reasonable resting perfusion was expected, there was a significant increase in MIB from 0.644 to 1.245, P < 0.001 and time intensity curves could be constructed showing wash-in and wash-out of contrast from the myocardium. In 10 segments supplied by significantly diseased vessels, MIB intensity increased from 1.044 to 1.874, P = 0.054. In myocardial segments supplied by non-diseased vessels, microsphere resonance also caused a drop in mean frequency of 140 KHz, P < 0.001, and permitted similar temporal analysis of myocardial perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative value of transthoracic and transoesophageal echocardiography before balloon dilatation of the mitral valve.

OBJECTIVE: To assess the relative merits of transthoracic and transoesophageal echocardiography before balloon dilatation of the mitral valve. DESIGN: Transthoracic and transoesophageal echocardiograms were prospectively performed in 35 patients being considered for balloon dilatation of the mitral valve. Echocardiograms were analysed for image quality, the assessment of valve morphology, the detection of left atrial thrombus, and the assessment of mitral regurgitation and other valvar pathology. PATIENTS: 35 consecutive patients with symptomatic dominant mitral stenosis. INTERVENTIONS: 30 eventually underwent balloon dilatation of the mitral valve by the Inoue technique. Five patients had mitral valve replacement. MAIN OUTCOME MEASURES: Echocardiographic and surgical detection of left atrial thrombus and successful, uncomplicated balloon dilatation of the mitral valve. RESULTS: Left atrial thrombus was detected in 1/35 patients by transthoracic studies compared with 6/35 from transoesophageal studies. Otherwise both techniques gave comparable results. Thrombus was confirmed at mitral valve replacement in five patients. Successful dilatation of the mitral valve was performed in 30 patients. CONCLUSIONS: Transthoracic echocardiography is a useful screening procedure but transoesophageal echocardiography is mandatory before balloon dilatation of the mitral valve for the detection of left atrial thrombus.

Residual atrial septal defects following balloon mitral valvuloplasty using different techniques. A transthoracic and transoesophageal echocardiography study demonstrating an advantage of the Inoue balloon.

The incidence and severity of atrial septal defects following balloon mitral valvuloplasty have been assessed using transthoracic and transoesophageal echocardiography in 20 patients 3-36 months following the procedure. In eight patients (group A) the atrial septum was dilated with an 8 mm Olbert balloon and either a double or bifoil balloon used to dilate the mitral valve. In 12 patients (group B) the Inoue balloon, with a slimmer deflated profile, was used following dilatation of the interatrial septum with a 14 French vessel dilator. In group A, using transthoracic echocardiography, one atrial septal defect was imaged and transatrial flow detected by colour flow Doppler in five patients. In seven of the eight patients transoesophageal echocardiography clearly imaged an atrial septal defect and left-to-right shunting was demonstrated by colour flow Doppler. Valsalva contrast studies revealed residual transatrial flow in all eight patients. The mean width of the colour flow jet was 5.8 mm. In group B patients, using transthoracic echocardiography, only one patient had evidence of residual transatrial flow (demonstrated by Valsalva contrast). Using transoesophageal echocardiography Valsalva contrast studies, transatrial flow was seen in 11 of the 12 patients. However, no defects were imaged and colour flow Doppler indicated left-to-right shunting in only two patients. The mean width of the colour flow jet was 1.5 mm. Transoesophageal echocardiography with colour flow Doppler and Valsalva contrast studies therefore provides a sensitive method for the detection of residual atrial septal defects following balloon mitral valvuloplasty. Transatrial flow persists in the majority of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Digital subtraction contrast echocardiography: a new method for the evaluation of regional myocardial perfusion.

The potential of contrast enhanced digital subtraction echocardiography to demonstrate and quantitate myocardial perfusion was evaluated in 36 patients undergoing routine coronary arteriography or angioplasty. In 24 technically successful studies, multiple cross sectional echocardiographic images, obtained before and after intracoronary (sonicated contrast) injection, were stored by high speed, real time data transfer to an on line minicomputer. Subsequent digital subtraction processing of the stored image data provided composite images in which the distribution of myocardial perfusion was easily seen. Quantitative analysis of peak enhanced myocardial grey level and washout half time successfully differentiated between myocardial segments in which angiography had suggested normal, reduced, and grossly impaired or absent perfusion. The results suggest that this new method of digital image capture and quantitative processing has substantial advantages over previous off line qualitative techniques. It is likely to be of considerable value for routine coronary arteriography, angioplasty, and coronary thrombolysis.

Unstable angina: early and late results of operative treatment.

Between January 1978 and May 1980 at King's College Hospital 68 patients of 300 patients treated consecutively by coronary artery bypass grafting (CABG) had presented with unstable angina. There were 58 males and 10 females age range 26 to 69 years, mean 54 years. Thirty-one patients (45%) had definite evidence of previous myocardial infarction, 4 had diabetes mellitus and 7 had left main stem stenosis greater than 50%. Seven cases (9.7%) required pre or peri-operative intra-aortic balloon pump assistance. Two subsets within this group of 68 patients with unstable angina were recognised. Fifty seven patients had CABG alone without any additional surgical procedure and there were 2 peri-operative deaths (mortality 3.5%). In 11 patients who had CABG plus additional surgical procedures including valve replacement or left ventricular aneurysmectomy there were 3 peri-operative deaths (mortality 27%). The overall mortality of the 68 patients was 5 deaths (7.4%). These results indicate that the operative mortality in patients with unstable angina having CABG alone is not significantly higher than the overall mortality at that time for the patients who had CABG for stable angina (2.4%).