Heinz Lambertz

Noninvasive Assessment of Coronary Flow Reserve with Transthoracic Signal–Enhanced Doppler Echocardiography

OBJECTIVESnThe feasibility of noninvasive assessment of coronary flow reserve (CFR) in the distal left anterior descending artery (LAD) with echocardiography-enhanced transthoracic pulsed wave Doppler guided by high-resolution transthoracic color Doppler (TTCD) was investigated. The results were compared with the degree of coronary diameter stenosis obtained during cardiac catheterization.nnnBACKGROUNDnAssessment of CFR has proven to be useful in the selection of patients undergoing invasive treatment of coronary artery disease and in estimating their prognosis. However, CFR could only be determined invasively in everyday practice during catheterization procedures. Recent development of high-resolution TTCD allows transthoracic visualization of distal LAD and supra-apical intramyocardial perforator branches and noninvasive measurement of CFR with pulsed wave Doppler technique.nnnMETHODSnCFR was determined by measuring the ratio of pulsed wave Doppler time velocity integral during adenosine-induced hyperemia (140 microgram/kg/min intravenously) to baseline value. If the baseline Doppler signal of LAD flow was insufficient, an echocardiography (echo) enhancer (Levovist) was used. Forty-five patients were examined by TTCD (7-MHz B-mode, 5-MHz color Doppler, and 3.5-MHz pulsed wave Doppler) after coronary angiography had been performed. Group 1 consisted of 15 patients without heart disease, group 2 of 15 patients with 50% to 85% isolated LAD diameter stenosis, and group 3 of 15 patients with >85% LAD diameter stenosis.nnnRESULTSnPeripheral LAD coronary flow at baseline condition was assessed in 40 (88%) patients with TTCD. CFR could be quantified in 36 (80%) of the 45 patients: in 18 patients without echo enhancer, and in 18 patients with echo-enhancing agent. CFR could not be assessed in 9 (20%) patients. CFR in the various groups was as follows: group 1, 3. 13 +/- 0.57; group 2, 2.23 +/- 0.20 (vs group 1: P <.01); and group 3, 1.64 +/- 0.30 (vs group 2: P <.02).nnnCONCLUSIONnCFR in the LAD can be determined in 80% of patients with pulsed wave Doppler guided by high-resolution TTCD combined with intravenously administered echo-enhancing agent.

Improvement of pulmonary venous flow Doppler signal after intravenous injection of Levovist

The analysis of the pulmonary venous flow Doppler pattern can assist in the determination of the severity of mitral regurgitation and, in conjunction with transmitral flow pattern, the assessment of left ventricular diastolic dysfunction. In approximately one third of the cases, however, transthoracic ultrasonography is not able to record an adequately analyzable pulmonary venous flow pattern. The aim of the study was to examine and compare the effect of the echo-enhancing agent Levovist on the pulsed-wave Doppler flow quality of the transthoracic (TTE) and transesophageal (TEE) recorded pulmonary venous flow. In 26 consecutive patients a qualitative (score system) and quantitative analysis of pulmonary venous flow pattern was obtained before and after peripheral venous injection of Levovist at concentrations of 200 mg/ml (low dose) and 400 mg/ml (high dose). The amount of measurable studies for the antegrade pulmonary venous flow increased after the injection of Levovist from 85% to 96% for TTE and from 96% to 100% for TEE. The retrograde flow as seen by TTE was adequately analyzable in only 46% before and in 73% after the injection of Levovist (p < 0.02). Before any contrast enhancement the retrograde pulmonary venous flow recorded by TEE could be analyzed in 77% of the patients, with the percentage increasing to 88% and 92% after the administration of a low and high dose of Levovist, respectively (p < 0.05). In particular, the quality score of the retrograde flow was significantly altered by the administration of Levovist (increase from 1.8 +/- 1.0 to 2.6 +/- 1.1 [low dose Levovist], p < 0.05 and to 2.7 +/- 1.3 [high dose Levovist], p < 0.05). The pulsed-wave Doppler interrogation by TTE without Levovist underestimated the velocities of the antegrade and retrograde pulmonary venous flow. After Levovist was administered, the recorded values were comparable to those obtained by TEE. An analogous pattern is encountered when quantifying the duration of the retrograde flow component. Thus the peripheral venous injection of Levovist leads to an improved quality of the pulmonary venous flow Doppler signal recorded by TTE. On qualitative and quantitative evaluation the values recorded by TTE after administration of Levovist are comparable to those of the TEE technique without an echo-enhancing agent.

New miniaturized versus conventional biplane transesophageal transducers: Recent clinical experience in adults

A subset of patients have substantial discomfort on examination with transesophageal echocardiography with the conventional probe, whereby the dimensions of the probe play a decisive role. Miniaturized biplane transducers have recently become available (2 x 32 channels, dimensions 9.5 x 8.7 mm, and circumference approximately 30% less than the conventional echoscope) and allow ultrasound examination at 3.5, 5.0 and 7.0 MHz. A prospective study was carried out in 90 patients to compare difficulties on insertion of the probe, subjective evaluation by the patient during examination, and the two-dimensional image, as well as Doppler and color-coded Doppler quality of the miniaturized biplane versus the conventional probe. In 62 patients, intubation of the esophagus proved less difficult with the smaller instrument and more difficult in nine cases. Seventy-six patients reported that they suffered less discomfort on use of the narrow instrument. Concomitant parasympatholytic medication was needed with the smaller probe in seven cases and 17 times with the conventional probe. As anticipated, quality of the two-dimensional image attained by the miniaturized probe was lower. With transmit/receive frequency of 7.0 MHz, however, image resolution was excellent in the near field of 5 cm and nearly equivalent to that of the conventional probe (5.0 MHz). Pulsed-wave and continuous wave Doppler and color-coded Doppler information from both probes was similar in quality. Whenever examination with a conventional transesophageal transducer promises to be difficult, or when sedation is contraindicated because of a severe illness or respiratory insufficiency, transesophageal echocardiography should be considered with a smaller biplane probe at higher transmit-receive frequencies.

Nichtinvasive Bestimmung der koronaren Flußreserve mittels signalverstärkter hochauflösender transthorakaler Farb-Doppler-Echokardiographie

UNLABELLEDnThe feasibility of non-invasive assessment of coronary flow reserve (CFR) in the left anterior descending artery (LAD) using echo-enhanced high-resolution transthoracic color Doppler echocardiography (TTCD) was investigated. The results were compared with the degree of coronary diameter-stenosis obtained during cardiac catheterization. CFR has proven to be useful in the selection of patients undergoing invasive treatment of coronary artery disease and in estimating their prognosis. However, CFR could only be determined in everyday practice invasively during catheterization procedures. Recent development of high-resolution TTCD allows transthoracic visualization of distal LAD and supra-apical intramyocardial perforator branches, and non-invasive measurement of CFR. CFR was determined by measuring the ratio of pulsed-wave Doppler time velocity integral during adenosine-induced hyperemia (140 micrograms/kg/min i.v.) to baseline value. If Doppler signal of LAD flow was insufficiently at basal condition, an echo enhancer (Levovist) was used. 45 patients were examined by TTCD (7 MHz B-mode, 5 MHz color Doppler, 3.5 MHz PW Doppler) after coronary angiography had been performed. Group I consisted of 15 patients without heart disease, Group II of 15 patients with 40 to 70% isolated LAD diameter stenosis, and Group III of 15 patients with > 70% LAD diameter stenosis. Peripheral LAD coronary flow at baseline condition was assessed in 40 patients (88%) using TTCD. CFR could be quantified in 36/45 patients (80%), in 18 patients without echo enhancer, and in 18 patients with echo-enhancing agent. In 9/45 patients CFR could not be assessed. CFR in Group I was 3.13 +/- 0.57, in Group II 2.23 +/- 0.20 (vs Group I p < 0.01) and in Group III 1.64 +/- 0.30 (vs Group II p < 0.02).nnnCONCLUSIONnCFR of LAD can be determined in 80% of patients by the synergistic use of high-resolution TTCD combined with intravenous given ultrasound echo-enhancing agent.ZusammenfassungDie derzeitige Ultraschalltechnologie erlaubt die Darstellung der distalen LAD-Abschnitte und der intramyokardialen Aufteilungsäste im apikalen sowie im apexnahen Myokard mittels hochauflösender 5-MHz-Farbdopplertechnik bei transthorakaler Beschallung. Erleichtert wird das Aufsuchen der Gefäßsegmente durch den Einsatz von lungengängigen Ultraschallsignalverstärkern. Der mittels PW-Doppler-Verfahren quantitativ bestimmte Koronarfluß unter Ruhebedingungen sowie nach Hyperämie mittels Adenosin (140 μg/kg KG/min intravenös) erlaubt die Berechnung der koronaren Flußreserve. Diese Bestimmung war bisher im klinischen Alltag lediglich invasiv möglich und hat sich synergistisch zum koronarmorphologischen Befund als äußerst hilfreich bei der weiteren Therapieplanung von Koronarinterventionen sowie deren Prognoseabschätzung erwiesen.Wir haben untersucht, wie häufig die nichtinvasive Bestimmung der koronaren Flußreserve im Bereich der LAD mittels hochfrequenter transthorakaler ultraschallsignalverstärkter Echokardiographie gelingt. Die Befunde wurden den koronarmorphologischen Ergebnissen des Herzkatheterismus gegenübergestellt. Hierzu wurden 45 Patienten nach vorheriger invasiver Abklärung transthorakal echokardiographisch untersucht (7-MHz-B-Bild, 5-MHz-Farbdoppler, 3,5-MHz-PW-Doppler). Gruppe I umfaßte 15 Patienten ohne organische Herzerkrankung, Gruppe II 15 Patienten mit 40-bis 70%iger isolierter LAD-Stenosierung, Gruppe III 15 Patienten mit >70%iger LAD-Stenose.Bei 40 Patienten (88%) gelang der Nachweis des basalen Koronarflusses im LAD-Versorgungsgebiet mittels Farbdopplertechnik. Bei 18 Patienten (40%) war es möglich, die koronare Flußreserve bereits nativ adäquat mittels PW-Doppler-Technik zu quantifizieren. Bei weiteren 18 Patienten (40%) gelang eine adäquate Erfassung der koronaren Flußreserve lediglich unter Zuhilfenahme des Ultraschallsignalverstärkers Levovist®. In Gruppe I betrug die koronare Flußreserve 3,13±0,57, in Gruppe II 2,23±0,20 (versus Gruppe I p<0,01) und in Gruppe III 1,64±0,30 (versus Gruppe II p<0,02).Schlußfolgerung: Durch den synergistischen Einsatz der hochauflösenden Farbdopplerechokardiographie in Verbindung mit peripher-venös verabreichten Ultraschallsignalverstärkern gelingt es, bei 80% der Patienten nichtinvasiv die koronare Flußreserve im LAD-Bereich quantitativ zu bestimmen.AbstractThe feasibility of non-invasive assessment of coronary flow reserve (CFR) in the left anterior descending artery (LAD) using echo-enhanced high-resolution transthoracic color Doppler echocardiography (TTCD) was investigated. The results were compared with the degree of coronary diameter-stenosis obtained during cardiac catheterization.CFR has proven to be useful in the selection of patients undergoing invasive treatment of coronary artery disease and in estimating their prognosis. However, CFR could only be determined in everyday practice invasively during catheterization procedures. Recent development of high-resolution TTCD allows transthoracic visualization of distal LAD and supra-apical intramyocardial perforator branches, and non-invasive measurement of CFR. CFR was determined by measuring the ratio of pulsed-wave Doppler time velocity integral during adenosine-induced hyperemia (140 μg/kg/min iv) to baseline value. If Doppler signal of LAD flow was insufficiently at basal condition, an echo enhancer (Levovist®) was used, 45 patients were examined by TTCD (7 MHz B-mode, 5 MHz color Doppler, 3.5 MHz PW Doppler) after coronary angiography had been performed. Group I consisted of 15 patients without heart disease, Group II of 15 patients with 40 to 70% isolated LAD diameter stenosis, and Group III of 15 patients with >70% LAD diameter stenosis.Peripheral LAD coronary flow at baseline condition was assessed in 40 patients (88%) using TTCD. CFR could be quantified in 36/45 patients (80%), in 18 patients without echo enhancer, and in 18 patients with echo-enhancing agent. In 9/45 patients CFR could not be assessed. CFR in Group I was 3.13±0.57, in Group II 2.23±0.20 (vs Group I p<0.01) and in Group III 1.64±0.30 (vs Group II p<0.02).Conclusion: CFR of LAD can be determined in 80% of patients by the synergistic use of high-resolution TTCD combined with intravenous given ultrasound echo-enhancing agent.