Frank A. Flachskampf

Long-term Clinical and Echocardiographic Follow-up After Surgical Correction of Hypertrophic Obstructive Cardiomyopathy With Extended Myectomy and Reconstruction of the Subvalvular Mitral Apparatus

BACKGROUND The standard surgical approach to hypertrophic obstructive cardiomyopathy (HOCM) was modified in the present series with a combination of extended myectomy with partial excision and mobilization of the papillary muscles. METHODS AND RESULTS Between 1979 and 1992, 58 patients (38 men and 20 women; mean age, 49 +/- 24 years) with HOCM were operated on with the use of this different technique. Their intraventricular gradients were 79 +/- 33 (+/- SD) mm Hg at rest and increased to 147 +/- 48 mm Hg with provocative maneuvers. Mild-to-moderate mitral regurgitation was present in 60% of the patients, and severe regurgitation was present in 5%. Ten patients required additional aortocoronary bypass graft surgery. Follow-up (mean, 84 months) was complete (100%). Hemodynamic improvement was documented by a significant (P < .01) decrease in left ventricular end-diastolic pressure from 19 +/- 9 to 14 +/- 6 mm Hg and reduction of basal outflow tract gradients to 5 +/- 7 mm Hg at rest and 16 +/- 24 mm Hg after provocation. Late mortality was 1.4% per patient-year, and no sudden cardiac deaths occurred during follow-up. Functional status was excellent for 84% of the patients; 8 patients were in New York Heart Association functional class III, and none were in class IV. Echocardiography revealed no outflow tract obstruction. CONCLUSIONS Extended myectomy and reconstruction of the subvalvular mitral apparatus in HOCM result in excellent functional improvement with relief of outflow tract obstruction. The technique can be performed safely despite its more aggressive surgical nature and allows an individualized strategy depending on the patients extent and distribution of left ventricular hypertrophy.

Planimetry of orifice area in aortic stenosis using multiplane transesophageal ecocardiography

OBJECTIVES The purpose of this study was to investigate whether the orifice area in aortic stenosis can be determined accurately and reliably by multiplane transesophageal echocardiography. BACKGROUND Monoplane transesophageal echocardiography has been used for planimetry of aortic valve orifice areas; however, obtaining a precise short-axis view is sometimes impossible. METHODS In 41 consecutive patients with known valvular calcific aortic stenosis (20 men, mean age 64 +/- 9 years), aortic valve orifice area was measured by planimetry using a multiplane transesophageal echocardiographic probe that allows full rotation of the cross-sectional plane. Results were compared with invasive measurements obtained by the Gorlin formula and areas determined noninvasively by transthoracic echocardiography using the continuity equation. RESULTS Multiplane transducer technology enabled the rotation of the cross-sectional plane from an exactly aligned long-axis view of the stenosed valve to a precise short-axis view without moving the tip of the echocardiographic probe, thus achieving an orifice cross section at a level predetermined in the long-axis view. Planimetry was feasible in 38 patients (93%). In three patients with pinhole stenosis (area determined by the Gorlin formula < 0.4 cm2), the valve area could not be exactly delineated. Correlation between areas derived by transesophageal echocardiographic planimetry (0.56 +/- 0.31 cm2) and by the Gorlin formula (0.58 +/- 0.31 cm2) was excellent (r = 0.95; standard deviation of regression [SDR] = 0.054; Y = 0.92X + 0.085, where Y = Gorlin area and X = planimetry area). Correlation between Gorlin- and continuity equation-derived areas (0.65 +/- 0.46 cm2) was r = 0.79; for continuity equation- and transesophageal planimetry-derived areas it was r = 0.83. Severe aortic stenosis (valve area < or = 0.75 cm2) was predicted with high sensitivity (96%) and specificity (88%). CONCLUSIONS Multiplane transesophageal echocardiography is a practical and accurate clinical tool for the assessment of the severity of aortic stenosis.

Standardized Guidelines for the Interpretation of Dobutamine Echocardiography Reduce Interinstitutional Variance in Interpretation

Subjective interpretation of dobutamine echocardiograms provides only moderate interinstitutional observer agreement if nonunified data acquisition and assessment criteria are applied. The present study was undertaken to evaluate parameters associated with low interinstitutional observer agreement in the interpretation of dobutamine echocardiograms and to analyze whether standardized interpretation criteria improve interinstitutional observer agreement. One hundred fifty dobutamine echocardiograms (dobutamine up to 40 microg/kg/min body weight and atropine up to 1 mg) were evaluated at 5 centers. Clinical, procedural, and echocardiographic parameters were included in the analysis of variables with significant impact on interinstitutional agreement. Standardized interpretative criteria were established, and 90 dobutamine echocardiograms were reanalyzed by 3 observers using a standardized image display. Multivariate analysis demonstrated low image quality (odds ratio [OR] 0.19, 95% confidence interval [CI] 0.08 to 0.45, p=0.0002), low severity of induced wall motion abnormality (OR 0.17, 95% CI 0.07 to 0.40, p <0.0001), and a low peak rate-pressure product (OR 0.93, 95% CI 0.43 to 2.27, p=0.0382) to result in a low interinstitutional agreement. Standardization of image display in cine loop format and of dobutamine stress echo interpretation criteria resulted in improvement in test result categorization as normal or abnormal, with a kappa value of 0.50, compared with 0.39 using the original subjective interpretation. In conclusion, image quality, the severity of induced wall motion abnormalities, and the obtained rate-pressure product have a significant impact on the interpretation homogeneity of dobutamine echocardiograms. Standardization of image display in cine loop format and of reading criteria results in improved interinstitutional agreement in interpretation of stress echocardiograms.

Does multiplane transesophageal echocardiography improve the assessment of prosthetic valve regurgitation

Assessment of prosthetic valve regurgitation by echocardiography remains difficult. To study the value of the newly introduced multiplane transesophageal technology for this purpose, prosthetic valve regurgitation was examined in 63 consecutive patients with 35 mitral and 33 aortic prostheses (23 bioprostheses and 45 mechanical prostheses). Transvalvular, paravalvular and, in mechanical valves, normal or pathologic transvalvular regurgitation were identified first with 0 degrees (transverse) and 90 degrees (longitudinal) planes combined with flexion of the echoscope tip and then additionally with multiple intermediary planes by transducer rotation. In a subgroup of 20 patients interobserver variability was evaluated. Both methods showed regurgitation in 56 of 68 valves; one additional case of regurgitation was seen by multiplane imaging only. However, 19 cases of regurgitation were not clearly classifiable by biplane transesophageal echocardiography compared with only three with multiplane transesophageal echocardiography. Grading of severity was concordant by both modalities in 66 and discordant in only two cases. Observers disagreed on severity in two of 20 cases based on biplane imaging but in none based on multiplane imaging; classification of regurgitation differed in six of 20 (biplane) and one of 20 (multiplane), respectively. Multiplane transesophageal imaging improves classification of prosthetic regurgitation but has little effect on severity grading.

3D-Echokardiographie: technisches Spielzeug auf der Suche nach klinischer Anwendung oder logische Weiterentwicklung des diagnostischen Instrumentariums?

Die echokardiographische Schnittbildtechnik ist in den letzten Jahren um die Möglichkeit der dreidimensionalen Rekonstruktion, jüngst auch um die Echtzeit-3D-Echokardiographie erweitert worden. Rekonstruktionsverfahren basieren entweder auf der akustischen oder elektromagnetischen Ortung des Schallkopfs während der Datenakquisition oder auf einer prädefinierten Schallstrahlbewegung von einer ortsfesten Position aus. Hierdurch lassen sich bewegte 3D-Bilder kardialer Strukturen erzeugen. Als Technik zur Veranschaulichung komplexer räumlicher Beziehungen ist die 3D-Echokardiographie insbesondere zur Untersuchung des Mitralrings und bei kongenitalen Fehlbildungen des Herzens eingesetzt worden. Die 3-D-Datensätze erlauben die nachträgliche Analyse in jeder gewünschten Schnittführung und somit sehr genaue Volumen- und Massenberechnungen, wie mehrere Arbeitsgruppen mit unterschiedlichen Methodiken übereinstimmend gezeigt haben. Die prinzipielle quantitative Überlegenheit der Methode beruht auf dem vollständigeren Datensatz im Vergleich zur 2D-Echokardiographie. Auch Farbdopplerbilder können dreidimensional rekonstruiert werden, allerdings derzeit nur als Grauwertbilder. Der breite klinische Einsatz der Methode ist derzeit durch den großen manuellen Aufwand zur Gewinnung quantitativer Daten und zum Teil noch unzureichende Bildqualität limitiert. Die rasche technische Entwicklung einschließlich der Echtzeit-3D-Technik weisen der Methode jedoch einen sicheren Platz im echokardiographischen Instrumentarium der Zukunft zu. In recent years, 3D echocardiographic reconstruction and real time 3D echocardiography have been developed. Reconstruction techniques are based on one of two principles: acoustic or electromagnetic location devices that identify the spatial position of the transducer during imaging, or transducers that image from a fixed position varying the sector orientation in a predefined way. Animated, dynamic recontructions of cardiac structures are possible, and the 3D data set can be sliced and viewed in any desired way after acquisition. The mitral annulus and congenital malformations of the heart have been imaged and studied successfully by 3D echo. Mass and volume calculations based on 3D data sets have been shown to be extraordinarily accurate by several investigators working with different techniques. Since the 3D data set is more comprehensive than any set of 2D images, such calculations are fundamentally superior to 2D or M-mode derived parameters. Color Doppler data can also be recontructed into 3D data sets, with possible applications to proximal convergence zone calculations. However, broad implementation of 3D echo in clinical practice is hampered to date by cumbersome manual tracing to derive quantitative parameters and sometimes by insufficient image quality. Nevertheless, the rapid technical evolution, now including real-time 3D echo, ensures an important role for 3D echo in future echocardiography.

Transesophageal echocardiography for prosthetic valve evaluation: is it always necessary?

Transesophageal echocardiography provides excellent images of mitral and aortic prostheses, due to its higher resolution and less interference from other cardiac structures. Since the introduction of transesophageal echocardiography, it has proved to be valuable for the evaluation of prosthetic heart valves. “Classic” indications include the evaluation of prosthetic valve endocarditis, the search for paravalvular abscesses, and the assessment of regurgitation in mechanical, especially mitral, prostheses. New technical developments such as biplane or multiplane transducers enhance the diagnostic capabilities of the technique. Transesophageal echocardiography can also have advantages in recognizing obstructive lesions such as thrombi or pannus, and help understand the complex morphology of prostheses in grafts. Transesophageal echocardiography should be considered a backup technique whenever transthoracic echocardiography, which always remains the primary approach, is inconclusive or negative in the presence of clinically suspected prosthetic valve malfunction.

Transösophageale dopplerechokardiographische Beurteilung der Mitralinsuffizienz: Vergleich von Jetfläche, pulmonalvenösem Flußprofil, proximalem Jetdurchmesser, maximaler Regurgitationsflußrate und Regurgitationsdurchtrittsfläche mit der Angiographie

Zur Schweregradeinteilung der Mitralinsuffizienz stehen verschiedene Methoden in der transösophagealen Echokardiographie zur Verfügung. Zum Vergleich der Methoden wurden 36 Patienten (60 ± 13 Jahre) mit angiographisch gesicherter Mitralinsuffizienz (Einteilung nach Sellers) innerhalb von 5 Tagen multiplan transösophageal untersucht. Gemessen wurde: 1. die maximale Farbdopplerjetfläche der Mitralinsuffizienz, 2. der Quotient aus maximaler systolischer und diastolischer pulmonalvenöser Flußgeschwindigkeit in der linken oberen Pulmonalvene, 3. die proximale Jetbreite der Mitralinsuffizienz, 4. der maximale momentane Regurgitationsfluß Qmax, gemessen mit der proximalen Flußkonvergenz-Methode, 5. die Regurgitationsfläche Areg aus dem Quotienten Qmax und der maximalen Regurgitationsgeschwindigkeit. Ergebnisse: Die Korrelation der Farbjetfläche (r = 0,4; p < 0,05) oder der pulmonalvenösen Flußgeschwindigkeit (r = –0,3; p = n.s.) mit dem angiographischen Schweregrad ist niedrig. Die Sensitivität der besten Trennwerte beträgt 69% für die Farbjetfläche und 83% für die pulmonalvenöse Flußgeschwindigkeit. Alle Sellers-III- und -IV-Fälle wurden mit einer proximalen Jetbreite ≥ 0,7 cm, einem Qmax≥ 300 ml/s oder Areg≥ 0,5 cm2 korrekt identifiziert (Sensitivitäten und Spezifitäten 83–100%). Der Spearman-Rangkoeffiziententest zeigte vergleichbar hohe Korrelationen (r = 0,75–0,77; p < 0,001) zwischen proximaler Jetbreite, Qmax oder Areg und angiographischem Schweregrad. Schlußfolgerung: Die Beurteilung der Mitralinsuffizienz in der multiplanen transösophagealen Echokardiographie nach der proximalen Flußkonvergrenzmethode oder der proximalen Jetbreite liefert vergleichbar gute Ergebnisse und ist der Einstufung nach der Farbjetfläche oder der pulmonalvenösen Flußgeschwindigkeit überlegen. In transesophageal echocardiography several methods have been used to grade mitral regurgitation. For a direct comparison of these techniques, 36 patients (60 ± 13 years) with native mitral regurgitation underwent multiplane transesophageal echocardiography and angiography within 5 days. We compared the following measurements: 1) The maximal color jet area of mitral regurgitation, 2) the ratio of maximal systolic to diastolic pulmonary venous flow velocity in the left upper pulmonary vein, 3) the proximal jet width of mitral regurgitation, 4) the maximal regurgitant flow rate Qmax, measured by the proximal convergence method, 5) the regurgitant orifice area Areg, calculated by dividing Qmax by maximal regurgitant velocity obtained by continuous wave Doppler. Results: The correlation between color jet area (r = 0.4; p < 0.05) or pulmonary venous flow (r = –0.3; p = n.s.) with angiographic severity of mitral regurgitation is low. The sensitivity of the retrospective best cut-off values is 69% (color jet area) and 83% (pulmonary venous flow). Using retrospective best cut-off values all patients with mitral regurgitation Sellers grade III and IV are correctly identified by a proximal jet width ≥ 0.7 cm, Qmax≥ 300 ml/s or a Areg≥ 0.5 cm2 (sensitivity and specifity of 83–100%). Spearmans rank coefficient demonstrated a high correlation (r = 0.75–0.77; p < 0.001) between proximal jet width, Qmax and Areg and with angiographic severity. Conclusion: Multiplane transesophageal echocardiographic grading of mitral regurgitation by proximal jet width or proximal convergence zone shows comparably good results and is clearly superior to grading by color jet area or pulmonary venous flow, if adequate image quality is achieved.

Overestimation of flow velocity through leaks in mechanical valve prostheses and through small orifices by continuous-wave Doppler

The reliability of continuous-wave Doppler flow velocity measurements through small regurgitant lesions, such as in prosthetic leakage, has not been systematically analyzed. To evaluate the accuracy of continuous-wave Doppler in prosthetic valve leakage and small orifices in an in vitro, steady-flow model-flow velocities through the leaks of twelve intact mechanical prostheses and through six circular nozzles (area 0.5 to 20 mm2) were measured at pressure drops between 30 and 105 mm Hg. These results were compared with those predicted by the modified Bernoulli equation. Laser Doppler anemometry of flow velocities through the nozzles was also performed. Despite high correlation, there was substantial overestimation of Bernoulli predicted velocities by echo Doppler in the prosthetic leaks (mean +12.3% +/- 9.4%; range 90.3% to 143.4%). In the nozzles < or = 10 mm2, but not in the largest (20 mm2) nozzle, there was also overestimation of the Bernoulli predicted velocities (mean +6.2% +/- 2%). Laser Doppler anemometry of flow velocities through the nozzles showed slightly lower values than predicted by the Bernoulli equation. Thus, continuous-wave echo Doppler overestimates flow velocities through small orifices. This apparently is, at least in part, due to transit time effects and should be taken into account when using echo Doppler in small (< 10 mm2) orifices, such as in mild to moderate regurgitant lesions and prosthetic valve leakage.

Application and Perspectives of Transesophageal Stress Echocardiography Using Monoplane and Biplane Instruments

Transesophageal stress echocardiography has been reported to have a high sensitivity and specificity for noninvasive identification and assessment of coronary artery disease. Its advantage is the virtually never obstructed acoustic window on the heart yielding superior image quality in almost all patients. Pharmacological stress as well as simultaneous atrial pacing—attaching electrodes to the echoscope—have been applied as stress modalities. Both transesophageal stress echocardiography modalities have been shown to be well tolerated, safe, and feasible in most patients. These promising initial experiences led to clinical application of this method for preoperative risk evaluation, for detection of restenosis after PTCA, and for evaluation of hibernating myocardium. This technique was also successful for evaluation of stress induced changes of transmitral and pulmonary venous flow in patients with left ventricular hypertrophy and coronary artery disease. Although all studies published so far were performed with monoplane technique, the sensitivity for detection of one‐vessel and, even more so, multivessel disease was high. However, apical and basal wall‐motion abnormalities may go undetected using monoplane equipment. The advent of biplane transesophageal imaging enables the visualization of more ventricular segments. Future studies will show to which degree biplane transesophageal stress echocardiography improves the diagnostic accuracy.