Harald Lethen

Analysis of interinstitutional observer agreement in interpretation of dobutamine stress echocardiograms

OBJECTIVES This study sought to determine the degree of interinstitutional agreement in the interpretation of dobutamine stress echocardiograms. BACKGROUND Dobutamine stress echocardiography involves subjective interpretation. Consistent methods for acquisition and interpretation are of critical importance for obtaining high interobserver agreement and for facilitating communication of test results. METHODS Five experienced centers were each asked to submit 30 dobutamine stress echocardiograms (dobutamine up to 40 micrograms/kg body weight per min and atropine up to 1 mg) obtained in patients undergoing coronary angiography. Thus, a total of 150 dobutamine stress echocardiograms were interpreted by each center without knowledge of any other patient data. Left ventricular wall motion was assessed using a 16-segment model but was otherwise not standardized. No patient was excluded because of poor image quality or inadequate stress level. Echocardiographic image quality was assessed using a five-point scale. RESULTS Angiographically significant coronary artery disease (> or = 50% diameter stenosis) was present in 95 patients (63%). By a majority decision (three or more centers), the sensitivity, specificity and accuracy of dobutamine echocardiography were 76%, 87% and 80%, respectively. Abnormal or normal results of stress echocardiography were agreed on by four or all five of the centers in 73% of patients (mean kappa value 0.37, fair agreement only). Agreement on the left anterior descending artery territory (78%) was similar to that for the combined right coronary artery/left circumflex artery territory (74%), and for specific segments the agreement ranged from 84% to 97% and was highest for the basal anterior segment and lowest for the basal inferior segment. Agreement was higher in patients with no (82%) or three-vessel coronary artery disease (100%) and lower in patients with one- or two-vessel disease (61% and 68%, respectively). Agreement on positivity or negativity of stress test results was 100% for patients with the highest image quality but only 43% for those with the lowest image quality (p = 0.003). CONCLUSIONS The current heterogeneity in data acquisition and assessment criteria among different centers results in low interinstitutional agreement in interpretation of stress echocardiograms. Agreement is higher in patients with no or advanced coronary artery disease and substantially lower in those with limited echocardiographic image quality. To increase interinstitutional agreement, better standardization of image acquisition and reading criteria of stress echocardiography is recommended.

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.

Comparative evaluation of bicycle and dobutamine stress echocardiography with perfusion scintigraphy and bicycle electrocardiogram for identification of coronary artery disease.

In 66 patients with suspected coronary artery disease (CAD), exercise electrocardiography (ECG), exercise echocardiography, dobutamine stress echocardiography (dosage, 5 to 40 micrograms/kg/min), single-photon emission computed tomography (SPECT) using methoxy-isobutyl-isonitrile (MIBI) and coronary angiography were performed prospectively to compare methods for detecting CAD. CAD was defined as 70% luminal area stenosis in at least 1 coronary artery at coronary angiography. Significant CAD was present in 50 patients. Compared with exercise ECG, exercise echocardiography, dobutamine stress echocardiography and MIBI-SPECT had a significantly higher sensitivity (52% vs 80, 79 and 89%; p < 0.01, p < 0.01 and p < 0.001, respectively). There were no significant differences in sensitivity between exercise echocardiography, dobutamine stress echocardiography and MIBI-SPECT. Specificity of MIBI-SPECT was lowest (71%), whereas exercise ECG, exercise and dobutamine echocardiography had higher specificities (93, 87 and 81%, respectively). Significance, however, was not achieved. Differences in overall accuracy between exercise echocardiography (82%), dobutamine stress echocardiography (80%) and MIBI-SPECT (85%) were not significant. Comparison with accuracy of exercise ECG (62%) was significant (p < 0.05, p < 0.05 and p < 0.01, respectively). In 1-vessel disease, exercise ECG had a lower sensitivity (45%) than exercise and dobutamine echocardiography and MIBI-SPECT (79, 78 and 84%; p < 0.02, p < 0.02 and p < 0.01, respectively). Regarding the 24 patients with false-negative exercise ECG results, 67% had positive exercise echocardiography findings, 71% positive dobutamine echocardiography results and 84% positive technetium-99m MIBI-SPECT results.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of transthoracic Doppler echocardiography to intracoronary Doppler guidewire measurements for assessment of coronary flow reserve in the left anterior descending artery for detection of restenosis after coronary angioplasty

Transthoracic Doppler echocardiography (TDE) has been described as a feasible and accurate technique to noninvasively assess coronary flow reserve (CFR) in the left anterior descending artery (LAD). This study was designed to evaluate whether serial assessment of CFR in the LAD using TDE allows detection of restenosis after previously performed angioplasty. Thirty-three consecutive patients with single-vessel coronary artery disease of the LAD scheduled for angioplasty underwent assessment of coronary flow velocity at rest and during adenosine-induced hyperemia in the distal LAD using high-frequency TDE. CFR was calculated as the ratio of hyperemic to basal systolic/diastolic mean velocity. Investigations were performed before and immediately after angioplasty, and at the time of control angiography after 3 months. CFR results by TDE were compared with intracoronary Doppler guide wire measurements. Adequate pulse-wave Doppler signals to measure CFR were obtained in 30 patients (91%) using TDE. There was close correlation between echocardiographically and intracoronary derived CFR results (r = 0.80, 0.79, and 0.87 before angioplasty, early after, and at 3- month control angiography, respectively; p <0.001). Using a cut-off value of CFR < or =2.0 to identify significant coronary artery disease, TDE detected LAD restenosis with a sensitivity of 89% and specificity of 90%. Thus, high-frequency TDE is a feasible technique to noninvasively assess CFR in the LAD with results closely corresponding to invasive measurements. Defining a cut-off value of CFR < or =2.0, the technique has the potential to reliably detect LAD stenosis after coronary intervention.

Validation of noninvasive assessment of coronary flow velocity reserve in the right coronary artery. A comparison of transthoracic echocardiographic results with intracoronary Doppler flow wire measurements

AIMS Assessment of coronary flow velocity reserve (CFR) noninvasively using transthoracic Doppler echocardiography (TDE) is validated for the left anterior descending artery only. We evaluated the feasibility and reproducibility to assess CFR using TDE in the right coronary artery, and compared the results with intracoronary Doppler flow wire (DFW) measurements. METHODS AND RESULTS Introduction of a modified apical 2-chamber view allows visualization of the posterior descending branch of the right coronary artery (RPD). 42 consecutive patients (31 men, mean age 61+/-10) with suspected coronary artery disease scheduled for coronary angiography underwent CFR assessment using TDE in fundamental imaging mode; the results were compared with DFW measurements. CFR could be taken noninvasively in 81% (34/42); in case of right dominant- or balanced coronary circulation type success rate was significantly higher (87%; 33/38) than in case of left dominant coronary circulation (25%; 1/4). Correlation between echocardiographically and intracoronary derived CFR results was significant (r=0.85, P<0.0001), as well as reproducibility (r=0.94, P<0.0001) and interobserver variability (r=0.78, P<0.0001). CONCLUSION Coronary flow reserve assessed in the peripheral RCA by TDE concurs very closely with intracoronary Doppler flow wire CFR results. This new approach allows feasible, accurate and reproducible measurement of CFR in the RCA.

Incremental value of biplane and multiplane transesophageal echocardiography for the assessment of active infective endocarditis.

In 41 patients with clinical evidence of active infective endocarditis, transesophageal echocardiography was performed in a stepwise manner, starting with evaluation of the monoplane views, followed by the longitudinal plane, and finally by the intermediate planes. Number, location, length, area, density, extent, and mobility of vegetations and abscesses were assessed in the monoplane, biplane, and best intermediate planes to identify and quantify the incremental value of the longitudinal and intermediate planes. Eighty-three vegetations and 6 abscesses were found. In 4 patients (10%) monoplane evaluation yielded false-negative results. There were no false-negative results using the biplane evaluation. However, when compared with multiplane evaluation, additional vegetations were missed in 23% of patients after monoplane and in 9% of patients after biplane evaluation. Three abscesses were missed using the monoplane and 1 was missed using the biplane technique. The area was underestimated in 60% of all vegetations (mean underestimation, 37% +/- 23% [SD] of maximal area) and length in 49% of cases (mean underestimation, 38% +/- 23% [SD] of maximal length) of all vegetations when biplane was compared with multiplane evaluation. Also, with monoplane and biplane evaluation, mobility and density were misinterpreted in 6% and 5% and 17% and 9% of all vegetations, respectively. Thus, multiplane transesophageal echocardiography is more accurate than the monoplane and biplane techniques in assessing patients with active infective endocarditis.

Improvement of coronary microvascular function after Angiotensin receptor blocker treatment with irbesartan in patients with systemic hypertension.

Patients with hypertension exhibit changes in vessel conductance and resistance. The aim of this study was to evaluate the effect of the angiotensin receptor blocker irbesartan on coronary microvascular function. Thirty‐six hypertensive patients without coronary artery or systemic disease were examined. Coronary flow velocity reserve (CFR) was measured using transthoracic Doppler echocardiography in 18 men (54±9 years) before and after 3 months of treatment with 600 mg/d of irbesartan and in 18 controls (55±11 years). Carotid intima‐media thickness (IMT) was evaluated with high‐resolution echocardiography. Baseline CFR did not differ between groups. CFR significantly improved in the irbesartan group (from 2.87±.42 to 3.78±.32; P<.001), but remained unchanged in controls (from 2.94±.61 to 3.06±.72; P=not significant). CFR improved with treatment independent of associated risk factors. BP decreased from 150±18 mm Hg to 129±25 mm Hg (P<.001) during treatment, whereas IMT and left ventricular mass index showed no significant differences at the end of the follow‐up period in both groups. Three‐month irbesartan treatment significantly increased CFR in patients with hypertension. This improvement is attributed to blockade of the renin‐angiotensin system. Coronary microvascular function was shown to improve independent of hypertrophy regression. Patients with lower baseline CFR tended to show a more pronounced CFR response. J Clin Hypertens (Greenwich). 2011;13:155–161.

Advances in noninvasive assessment of valvular heart disease.

Echocardiography continues to be the noninvasive method of choice in the evaluation of valvular heart disease. Important recent developments include clinical validation of approaches used to quantify valvular regurgitation, in particular the proximal flow convergence zone method; use of transesophageal imaging to monitor and evaluate surgical or percutaneous interventions in valvular heart disease, in particular mitral valve repair; insight into flow-related stretch of the orifice area in aortic stenosis; and validation of nuclear magnetic resonance imaging in small series for quantification of left-sided valvular stenotic and regurgitant lesions.

Nicht invasive Bestimmung der koronaren Flussreserve mittels Echokardiographie

Coronary flow reserve (CFR) can be determined echocardiographically in the LAD in about 90% and in the RCA in more than 70% of patients, respectively, by the use of modern high-resolution ultrasound equipment. For this purpose either high frequency fundamental imaging or echo-contrast enhanced harmonic Doppler technology is used. The main advantage of the method lies in its noninvasiveness and the lack of radiation exposure. In combination with coronary morphologic findings obtained from heart catheterization, CFR is helpful in the planning of further invasive procedures for coronary artery disease and in the estimation of the prognosis of such procedures. The functional status after PTCA of LAD/RCA or mammary bypass surgery can be evaluated during follow-up monitoring. Alteration in the coronary microcirculation can also be discovered in a non-invasive manner; improvement of microcirculatory disorders by adequate therapy can be assessed by serial measurements of CFR Mittels hochauflösender transthorakaler Echokardiographie ist die Darstellung der mittleren und distalen RIVA-Abschnitte und des Mammarie-Bypass mit nachfolgender Bestimmung der CFR in über 90% der Fälle möglich. Die Bestimmung der CFR gelingt in der rechten Koronararterie in über 70% der Fälle. Das Verfahren ist nicht invasiv, für den Patienten nur gering belastend und kann wiederholt durchgeführt werden. Die echokardiographische Erfassung der CFR stellt eine Bereicherung in der nichtinvasiven Diagnostik von kardialen Makro- als auch Mikrozirkulationsstörungen dar. Zusammen mit dem koronarmorphologischem Befund ist das Verfahren hilfreich bei der Planung von Koronarinterventionen des RIVA und der RCA, in der Verlaufsbeurteilung kann es zur Restenoseerkennung eingesetzt werden. Nach Anlage eines Mammaria-Bypass ermöglicht die CFR-Messung im Bypass oder distal der Bypass-Anastomose die Funktionsbeurteilung. Mikrozirkulationsstörungen können bei ausgeschlossener koronarer Herzerkrankung mittels CFR-Bestimmung erkannt und unter Therapie im Verlauf beobachtet werden.

Transösophageale EchokardiographieDurchführung und diagnostische Möglichkeiten

ZusammenfassungBei der transösophagealen Echokardiographie (TEE) stellt die Speiseröhre den Zugangsweg für die Ultraschalluntersuchung des Herzens dar. Die unmittelbare Nähe zum Herzen macht den Ösophagus zum idealen Ausgangspunkt für die Echokardiographie, da von hier die Darstellung der kardialen Strukturen sowie der großen herznahen Gefäße weitgehend ungehindert, mit hoher Beschallungsfrequenz und daher mit sehr gutem Auflösungsvermögen durchführbar ist. Die im Vergleich zur transthorakalen Echokardiographie höhere Schallfrequenz ermöglicht eine hervorragende zweidimensionale Bildqualität bei gleichzeitig verbesserter Doppler-Aufzeichnung. Durch die fehlende Interferenz thorakaler oder pulmonaler Strukturen kann die Untersuchung auch bei Patienten mit fehlendem oder unzureichendem transthorakalem Schallfenster durchgeführt werden.