Usefulness of accelerated diastolic reversed flow along the left ventricular posterior wall in aortic regurgitation for estimating left ventricular function

Usefulness of accelerated diastolic reversed flow along the left ventricular posterior wall in aortic regurgitation for estimating left ventricular function

Usefulness of Accelerated Diastolic Reversed Flow Along the Left Ventricular Posterior Wall in Aortic Regurgitation for Estimating Left Ventkdar Funct...

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Usefulness of Accelerated Diastolic Reversed Flow Along the Left Ventricular Posterior Wall in Aortic Regurgitation for Estimating Left Ventkdar Function Takashi Koyama, MD, Satoshi Ogawa, MD, Makoto Akaishi, MD, Tsutomu Yoshikawa, MD, Tomomi Meguro, MD, Shunnosuke Handa, MD, and Yoshiro Nakamura, MD patients with AR whose regurgitant jlow was directed toward the LVposterior baseinstead of apex were also excluded beforehand becauseof the lack of diastolic reversedflow along the LVposterior wall. All patients were studied at rest in the left lateral decubitusposition with a Hewlett-Packard echocardiographic instrument (7703OA Ultrasound System). Pulsed-wave Doppler signals were obtained from the apical long-axis view using a 2.5 MHz transducer. Mitraljlow signals weresampled at the level of the tips of the mitral leaflets. Diastolic reversedflow signals were sampled at the centerof the blue color signals representing that flow (Figure I). If there was no visible diastolic reversedjlow signals, we attempted to detect Doppler signals of diastolic reversedjlow betweenthe posterior mitral leaflet and posterobasal wall at the level of the tips of the mitral leaflets, wherediastolic reversedjlow is supposedto be present. Diastolic reversedjlow signals were consideredpresent if well enveloped,biphasic and with a velocity of >0.2 m/s. Statistical significance of a difference of 2 means were determined by Student’s t test. Statistical correlation betweenacceleration of diastolic reversedflow and percentfractional shortening or LV end-systolic dimension were obtained using linear or nonlinear regression analysis. In all patients with severeAR, diastolic reversedjlow signals could be detectedusing the pulsed-waveDoppler method, except for the particular patients described above.In the control group, diastolic reversedflow signals could not be detectedin 2patients. These2 patients were excluded from statistical analysis. From the Cardiopulmonary Division, Department of Medicine and Diastolic reversedflow signals were biphasic and Department of Geriatrics, Keio University School of Medicine, 35 were composedof 2 different signals similar to those Shinanomachi, Shijuku-ku, Tokyo 160, Japan. Manuscript received February 3, 1992; revised manuscript received and accepted May 4, observedin mitral flow signals. Each signal corresponding to E wave (rapidjilling) or A wave (atria1 contrac1992.

imely indication of surgical correction of aortic re T gurgitation (AR) dependson precise evaluation of left ventricular (LV) function. However, it may still be difficult to accurately predict surgical outcomewith only currently available indexes of LV function. We undertook this study to obtain a novel index of LV function from altered LV fluid dynamics in patients with AR. AR flow is expectedto causedefinitive changesin intraventricular flow distributions. The degree of such changes may be mainly determined by the severity of regurgitation but variously affected by chamber size, diastolic property and filling pressureof the left ventricle. Therefore, our hypothesisis that the changesin the intraventricular fluid dynamics reflect LV function in patients with similar degreesof AR. We testedthis hypothesisin patients with severeAR using the Doppler ultrasound technique and obtained a novel index for estimating LV function. Weprospectively studied 30 patients, 21 men and 9 women(mean age 53 years [range 25 to 84) with severe AR undergoing routine echocardiography at Keio University Hospital. Eleven normal subjects (mean age 52 years [range 35 to 691) without any cardiac abnormalities wereselectedas the control group. Only patients with technically good quality studies were included. The severity of AR was evaluated by Doppler color jlow imaging, and only patients with a regurgitantflow transmitting over the papillary muscle level were selected. Patients with atria1fibrillation or coexisting mitral stenosis, or both, were excluded becauseof an abnormal mitral flow pattern irrespective of LV function. Seven

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tion) in mitral flow signals were termed E’ wave or A’ wave (Figure 2). Each wave of diastolic reversedflow signals followed the corresponding wave of mitral flow signals with a slight time delay (30 to 90 ms). The mean peak velocities of each wave, including those of mitral jlow, are listed in Table I. The peak velocity ratio of diastolic reversedand mitral jlows for each corresponding componentwas compared betweenthe patient and control groups (Figure 3). In the patient group, the peak velocity ratio of E’ and E waves (E’/E) was significantly higher than those in the control group, indicating that diastolic reversedflow is accelerated during the rapid filling phase. E’/E was roughly and linearly correlated with both percentfractional shortening and LV end-systolic dimension (r = -0.49 [p
TABLE I Mean Peak Wave Velocities of Mitral Flow and Diastolic Reversed Flow

E-wave velocity A-wave velocity Y-wave velocity K-wave velocity All

Patient Group

Control Group (n = 9)

Velocities (cm/s)

71 69 50 50

2 2 r 2

(n = 30) 59-c 66 r 532 52 iz

14 18 18 16

19 18 12 16

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sion; however,the index showeda progressiveincreasein accordancewith progression of LV dysfunction. In the presentstudy, we demonstratedan acceleration of diastolic reversedflow as altered fluid dynamics in the left ventricle of patients with AR. The energy sourceof the accelerationof diastolic reversedflow is expectedto be supplied by the regurgitant flow energy, becausethe acceleration of diastolic reversed flow is likely to be causedby a driving forceof regurgitant flow turning up at the LV apex.Therefore, the degreeof the accelerationof diastolic reversed flow seemsto be determined by the initial potential energyof regurgitant flow and the energy absorbingcapacity of the left ventricle. The latter consists of chambersize,ventricular relaxation, chamberstiffness and ftiig pressureof the left ventricle. We therefore hypothesized that changesin intraventricular flow dynamics reflect LV function in patients with similar de greesof AR and proved the hypothesisin patients with severeAR. We used the ratio of F/E and A/A, the DRFp index, as an index of altered flmd dynamics in the left ventricle. This index may operate on the combining effectsof the 4 variablesthat determine the energy-absorbing capacity of the left ventricle. Slowed ventricular relaxation and increasedchamber stiffness decreasesthe energy absorbing capacity of the left ventricle and may facilitate the acceleration of diastolic reversedflow. On the other hand, chamber dilatation and elevated filling pressureincrease the energy-absorbingcapacity of the left ventricle and may impedethe accelerationof diastolic reversedflow. Although chamberstiffnessis a function of

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filling pressurein the acute phaseof volume overloading, chronic volume overloading causesslowed relaxation,’ increased chamber stiffness2~3 and chamber dilatation with little elevation of filling pressure4as a result of eccentric hypertrophy. The initiation of a significant elevation of filling pressuremay representa transition from hypertrophied myocardium to failing myocardium in patients with chronic AR. The net effect of slowedrelaxation, increasedchamber stiffnessand chamber dilation is an acceleration of diastolic reversedflow, judging from the results of the present study. In this case,E’ and A’ wavesmay be acceleratedin a similar degree.However, when an elevationin filling pressuresupervenesas a result of the initiation of myocardial failure, the accelerationof diastolic reversedflow, especiallythat of the later component of diastolic reversed flow, may be impeded. As a result of the interference of the acceleration of A’ wave, the accelerationof E’ wavemay becomedominant, which results in an increasein the ratio of E’/E and A’/A, the DRFpindex. This may explain the characteristic responseof the DRFpindex to progressionof LV dysfunction.

In this study, we did not demonstratesuperiority of the DRFpindex to other parameters to estimate LV function. It should be clear only when long-term followup of patients with AR is doneusing this index. However, this index derives not from ventricular mechanics but from ventricular fluid dynamics. Changesin myocardial function directly influence ventricular fluid dynamics without any intervention. Any trivial changesin LV func tion would be reflectedbetter and more promptly on fluid dynamics than on ventricular mechanics.Therefore, we believe that the DRFpindex may becomea useful and sensitive parameter for estimating LV function in patients with AR. 1. Eichhom P, Grimm J, Koch R, Hess 0, Carroll J, Krayenbuehl HP. Left ventricular relaxation in patients with left ventricular hypertrophy secondaryto aortic valve disease.Circulafion 1982;65:1395-1404. 2. Pinsky WW, Lewis RM, Hartley CJ, Entman ML. Permanentchangesof ventricular contractility and compliancein chronic volume overload.Am J Whysiol 1979;237:H575-H583. 3. McCuUaghWH, Cove11JW, RossJ Jr. Left ventricular dilatation and diastolic compliance changesduring chronic volume overloading. Circdofion 1972;45: 943-95 1. 4. Lewis BS, Gotsman MS. Current conceptsof left ventricular relaxation and

compliance.Am HearY .I 1980;99:101-112.

Assessment of Aortic Vahre Area in Aortic Stenosis by Magnetic Resonance imaging Markku Kupari, MD, Pauli Hekali, MD, Pekka Keto, MD, Veli-Pekka Poutanen, MSC, Leena Porkka, Heikki Turto, MD, Markku S. Nieminen, MD, Lauri Toivonen, MD, Timo Ikonen, MD, Markku Ventil& MSC, and Juhani Heikkila, MD

MSC,

equation.* For technical reasons,the Doppler interrogation is not always successful,however, and a substitute noninvasive method for AVA determination would be at cardiac catheterization1or noninvasively using trans- welcome. Ultrafast computed tomography has shown thoracic Doppler echocardiography and the continuity some promise in this respect,3and the present report describesour initial experiencewith the useof magnetic From the Division of Cardiology (Fit went of Medicine), and resonanceimaging (MRI) to directly visualize and quanthe Department of Diagnostic Radiology, Helsinki University Central tify the systolic aortic valve orifice. Hospital, 00290 HAinld, Fiid. This study was supportedby F’aavo Westudied 48 patients, 25 men and 23 womenaged Nurmi Foundation, Helsinki, Find. Manuscript received February 41 to 78years (mean63). They underwentcardiac cathe11,1992; revisedmanuscript receivedand acceptedMay 18,1992. he ultimate determinant of the clinical significance T of valvular aortic stenosis(AS) is the systolic aortic valve orifice area (AVA). AVA can be quantified either

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