Detection of Left Ventricular Dysfunction Using Early Diastolic Mitral Annular Velocity in Patients Undergoing Mitral Valve Repair for Mitral Regurgitation Koichi Suehiro, MD, Katsuaki Tanaka, MD, PhD, Tadashi Matsuura, MD, PhD, Tomoharu Funao, MD, PhD, Tokuhiro Yamada, MD, PhD, Takashi Mori, MD, PhD, and Kiyonobu Nishikawa, MD, PhD Objectives: Ejection fraction (EF) is considered an unreliable index in patients with mitral regurgitation (MR). Left ventricular dysfunction (LVD) frequently occurs after mitral valve repair (MVR), with the incidence being 15% to 34%. This study aimed at investigating whether preoperative early diastolic mitral annular velocity (E′) is associated with LVD after MVR. Design: Retrospective study. Setting: University hospital. Participants: Sixty-three patients undergoing MVR for severe MR. Interventions: None. Measurements and Main Results: LVD was defined by a postoperative EF of o50%. Receiver operating characteristic (ROC) analysis and separate multivariate logistic regression models were used to examine the independent effects of echocardiographic variables on LVD risk. LVD occurred in 20 patients (31.7%). E′ was correlated significantly with perioperative EF change (p ¼ 0.019, r ¼ 0.293). The area under
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HRONIC MITRAL REGURGITATION (MR) can lead to left ventricular dysfunction (LVD) and heart failure. The optimal timing of surgical intervention is, thus, very important. In cardiac surgery patients, ejection fraction (EF), as measured by echocardiography, is the most commonly used parameter for assessing left ventricular function. However, EF is considered unreliable in patients with MR.1–3 In these patients, left ventricular systolic function often is overestimated by ejection indices, and EF often remains normal. This is because, in the presence of MR, the left ventricle ejects toward both the left atrium (low impedance) and aorta, thereby decreasing the left ventricular afterload. Therefore, an unsuspected LVD after mitral valve repair often occurs at an incidence of 15% to 34%.4–6 Under these circumstances, an index for predicting LVD would be useful. Recent studies have shown that indices such as Tei index, MR volume, and left ventricular end-systolic diameter (Ds) are good predictors of LVD after mitral valve repair in patients with severe MR.4–7 Tissue Doppler imaging (TDI), a comparatively new method for measuring myocardial velocity by echocardiography, has been used to assess systolic and diastolic function and has shown prognostic utility in patients with heart failure,8–11 myocardial infarction,12,13 and end-stage renal disease.14 Studies also have shown that early diastolic mitral annular velocity (E′), as measured by TDI, reflects left ventricular diastolic function and predicts the hospital outcome in critically ill patients.15–17 E′ is reported to be a good predictor of cardiac events (heart failure, cardiac death) in patients with both preserved systolic function and systolic dysfunction,18,19 and also reflects the degree of progression of the cardiac diseases. Therefore, the authors anticipated that E′ can predict unexpected LVD after surgical correction of MR. This study aimed at determining whether the preoperative E′ value measured by transthoracic echocardiography (TTE) was associated with left ventricular myocardial dysfunction after mitral valve repair in patients with severe MR.
the ROC curve was 0.777 (95% confidence interval [CI]: 0.6440.911) for E′, and the optimal threshold value of E′ for predicting LVD was 6.5 cm/s (sensitivity, 80%; specificity, 67.4%). The frequency of LVD was 33.3% for a preoperative EF o 65%; 44.4% for preoperative EF o 65% and left ventricular end-systolic diameter 432 mm; and 88.9% for preoperative EF o 65%, left ventricular end-systolic diameter 432 mm, and E′ o 6.5 cm/s (p ¼ 0.006). Multivariate logistic regression models analysis revealed that E′ was an independent risk factor for LVD (odds ratio: 1.98, 95% CI: 1.22-3.22). Conclusions: Preoperative E′ value was an independent risk factor of LVD after mitral valve repair in patients with severe MR. & 2014 Elsevier Inc. All rights reserved. KEY WORDS: mitral regurgitation, early diastolic mitral annular velocity, left ventricular dysfunction, mitral valve repair
SUBJECTS AND METHODS The authors obtained approval from the ethics committee of their hospital. The patients who underwent mitral valve repair for chronic severe MR between May 2007 and December 2012 were retrospectively enrolled in this study. They excluded patients with aortic regurgitation and stenosis of more than mild degree, mitral stenosis of any degree, and preoperative LVD (preoperative EF of o50%). The Philips echocardiography machine iE33 (Philips Medical Systems, Bothell, WA) was used. All echocardiographic data in this study were obtained by TTE. Standard 2-dimensional and Doppler TTE were performed by cardiologists in the authors’ institution before (15 ⫾ 9.1 days) and after (9.0 ⫾ 2.1 days) surgery. The clinicians who analyzed the echo images were blinded to further clinical information. Left ventricular EF was measured by the Simpson disk method,20 and postoperative LVD was defined by a postoperative EF of o50%. MR volume was measured using the proximal isovelocity surface area or quantitative Doppler method. In patients with tricuspid regurgitation, continuous-wave Doppler was used to measure the maximum regurgitation velocity, and the pulmonary artery systolic pressure was calculated using the simplified Bernoulli equation, assuming the right atrial pressure was 10 mmHg. Early diastolic mitral annular velocity was measured by pulse-wave TDI. The sample volume was set at the septal mitral annulus in the four-chamber view. The E′ value at the septal annulus was found to be more useful in evaluating left ventricular diastolic function than that of the lateral annulus.21 Transmitral flow was obtained using pulse-wave Doppler at the tip of the mitral leaflets in the 4-chamber view. The ratio
From the Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka, Japan. Address reprint requests to Koichi Suehiro, MD, Osaka City University Graduate School of Medicine, Department of Anesthesiology, 1-5-7 Asahimachi, Abenoku, Osaka City, Osaka 545-8586, Japan. E-mail: [email protected] © 2014 Elsevier Inc. All rights reserved. 1053-0770/2601-0001$36.00/0 http://dx.doi.org/10.1053/j.jvca.2013.07.013
Journal of Cardiothoracic and Vascular Anesthesia, Vol 28, No 1 (February), 2014: pp 25–30
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SUEHIRO ET AL
of early diastolic transmitral velocity (E) to E′ was calculated. In patients with atrial fibrillation, averages of 5 cardiac cycles were calculated for all measurements at the end-expiration period. In patients with sinus rhythm, all echocardiographic variables were measured for 3 cardiac cycles, and the average values were calculated. General anesthesia was induced with midazolam (0.1 mg/kg), propofol (1 mg/kg), fentanyl (2 to 5 μg/kg), and rocuronium (0.8 to 1 mg/kg) and maintained using sevoflurane (1.0 to 2.0%), fentanyl (20 to 40 μg/kg per case), and rocuronium (15 to 30 mg/h). The authors controlled the depth of anesthesia at BIS values (measured using BIS monitor v. 4.0, Aspect Medical System, Natick, MA) between 40 and 60. During cardiopulmonary bypass (CPB), propofol was administered continuously (2 to 3 mg/kg/h) to maintain general anesthesia. After induction of general anesthesia, an arterial pressure catheter was inserted into the radial artery in addition to inserting a central venous catheter and a thermodilution pulmonary artery catheter into the right internal jugular vein. The authors performed standard CPB procedures in all patients. Standard flow rates of 2.4 to 2.6 L/min/m2 were obtained to maintain the mean arterial pressure between 50 and 80 mmHg. Alpha-stat management was used to maintain PaCO2 at Z40 mmHg and hematocrit at 422%. Mild hypothermia was maintained with a rectal temperature of 321C, and both anterograde and retrograde crystalloid cardioplegia were used. The most common surgical technique for anterior leaflet prolapse was repair of the chords, and posterior leaflet prolapse usually was repaired by the resection and suture technique. In all cases, an annuloplasty ring (Edwards Lifesciences, Irvine, CA) was used. All procedures were performed by the same surgical team. The endpoint of the authors’ study was the occurrence of postoperative LVD. Postoperative LVD was defined by a postoperative EF of o50%. They divided the patients into 2 groups according to the postoperative EF (D group, postoperative EF o 50%; N group, postoperative EF Z 50%). Intergroup comparison was made in terms of perioperative characteristics. To determine the threshold of the preoperative E′ value in predicting postoperative LVD, the authors performed a receiver operating characteristic (ROC) analysis to investigate the prognostic performance of preoperative echocardiographic value of E′, E/E′, EF, Ds, and MR volume with regard to postoperative LVD (EF o 50%). As per the American College of Cardiology (ACC)/ American Heart Association (AHA) guidelines,22 mitral valve surgery is recommended for patients with early signs of LVD (Ds of Z40 mm or EF of r60%). Therefore, the authors investigated the incidence of postoperative LVD on the basis of preoperative EF, Ds, and E′ values. The cut-off values were determined by ROC analysis. Separate multivariate logistic regression models were used to examine the independent effects of the preoperative echocardiographic variables on the risk of postoperative LVD. All results were expressed as mean and standard deviation unless otherwise indicated. Statistical analysis was performed using Sigma Plot 11.2 (Systat Software Inc., San Jose, CA). The authors used the Student’s t-test, χ2 test, and Mann-Whitney U test to compare the demographic data. For all analyses, a p value of o0.05 was considered significant. RESULTS
Eighty patients were enrolled in this study. Seventeen patients were excluded (8 patients with preoperative EF o 50% and 9 patients with aortic valve disease), and the final study population comprised 63 patients (24 women and 39 men). Valvular prolapse or flail involved the anterior leaflet in 11 patients (17%), posterior leaflet in 40 patients (63%), and both leaflets in 12 patients (19%). All patients had less than mild MR after surgery. Perioperative characteristics of the studied patients are shown in Table 1. Postoperative LVD occurred in 20 patients (31.7%). The D and N groups showed significant differences in
Ds, E′, and E/E′ (p o 0.05). Results of correlation analysis between preoperative E′ value and perioperative EF change are shown in Figure 1. The preoperative E′ value was correlated significantly with perioperative EF change (p ¼ 0.019, r ¼ 0.293). ROC analysis was performed to evaluate the prognostic performance of E′, E/E′, preoperative EF, Ds, and MR volume with regard to postoperative LVD (Fig 2A, 2B). The areas under the ROC curves were 0.777 (95% confidence interval [CI]: 0.644-0.911) for E′ and 0.711 (95% CI: 0.577-0.844) for E/E′, which were significantly higher than those for preoperative EF value (p o 0.05) (preoperative EF: 0.523, 95% CI: 0.359-0.686) (Fig 2A). In Figure 2B, the areas under the ROC curves were 0.691 (95% CI: 0.536-0.847) for Ds and 0.652 (95% CI: 0.513-0.790) for E/E′, both of which were statistically significant (p o 0.05). The optimal threshold value of E0 in predicting postoperative LVD was 6.5 cm/s (sensitivity, 80%; specificity, 67.4%). Figure 3 shows the incidence of postoperative LVD determined on the basis of preoperative EF, Ds, and E′ values. The incidence Table 1. Perioperative Characteristics in Studied Patients
Age (yr) Gender (M/F) Height (cm) Body weight (kg) NYHA classification I/II/III/IV Preoperative complication Hypertension, n (%) Diabetes mellitus, n (%) Atrial fibrillation, n (%) Angina, n (%) Echocardiography data Preoperative LV EF (%) Prolapse Anterior/Posterior leaflet Both leaflets LV end-diastolic diameter (mm) LV end-systolic diameter (mm) E (cm/s) E′ (cm/s) E / E′ E-wave deceleration time (ms) MR regurgitation volume (mL) Systolic PAP (mmHg) Anesthesia time (min) Surgery time (min) CPB time (min) Cross-clamp time (min)
D group
N group
(n ¼ 20)
(n ¼ 43)
65.3 ⫾ 12.5 65.5 ⫾ 10.9 13/10 26/14 159 ⫾ 11.2 161 ⫾ 9.9 54.9 ⫾ 15.0 57.8 ⫾ 11.6 2/11/7/0 12/26/5/0 12 1 6 1
(60) (5.0) (30) (5.0)
19 4 13 1
(44) (9.3) (30) (2.3)
p Value
0.927 0.505 0.458 0.451 0.06 0.243 0.556 0.985 0.573
64.4 ⫾ 5.8
64.8 ⫾ 4.8
0.775
4/13 3 58.2 ⫾ 6.8
7/27 9 54.7 ⫾ 7.7
0.835
35.3 ⫾ 8.5
30.7 ⫾ 5.6
0.035*
120 ⫾ 5.69 ⫾ 21.8 ⫾ 194 ⫾ 71.8 ⫾ 43.2 ⫾ 342 ⫾ 277 ⫾ 175 ⫾ 130 ⫾
117 7.21 16.9 206 65.3 41.3 350 279 173 136
37.2 1.67 7.43 58.5 14.9 14.8 70.1 62.0 42.7 33.1
⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾
0.09
37.0 0.755 1.54 p o 0.001* 5.63 0.005* 38.3 0.438 13.2 0.09 15.0 0.645 62.8 0.661 54.0 0.924 38.3 0.841 35.1 0.532
NOTE. Data are expressed as mean ⫾ SD. D group: patients with postoperative EF o 50%, N group: patients with postoperative EF Z 50%. Abbreviations: CPB, cardiopulmonary bypass; E, peak mitral valve early diastolic velocity; E′, tissue Doppler peak early diastolic myocardial velocity; EF, ejection fraction; LV, left ventricle; MR, mitral regurgitation; NYHA, New York Heart Association; PAP, pulmonary artery pressure. *p o 0.05 statistically significant.
DETECTION OF LEFT VENTRICULAR DYSFUNCTION
Fig 1. E0 , early diastolic mitral annular velocity; EF, ejection fraction. Correlation analysis between preoperative E′ value and perioperative EF change. The preoperative E′ value was correlated significantly with perioperative EF change (p ¼ 0.019, r ¼ 0.293).
of postoperative LVD was 33.3% when preoperative EF was o65%. A combined analysis revealed that the occurrence of postoperative LVD was 44.4% at a preoperative EF of o65% and Ds of 432 mm and 88.9% at preoperative EF of o65%, Ds 432 mm, and E′ o6.5 cm/s (p for trend ¼ 0.006). The authors used multivariate logistic regression models to examine the independent effects of preoperative echocardiographic variables on the risk of developing postoperative LVD, which are shown in Table 2. Preoperative E′ value was an independent risk factor of LVD after mitral valve repair in patients with severe MR. DISCUSSION
This is the first published study on the correlation between preoperative E′ value and postoperative LVD after mitral valve repair in patients with severe MR. ROC analysis showed that
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preoperative E′ value was a better predictor of postoperative LVD than the preoperative echocardiographic values of EF, E/ E′, Ds, and MR volume, and the optimal threshold value for E′ was 6.5 cm/s with a sensitivity of 80% and specificity of 67.4%. As shown in Figure 1, the preoperative E′ value also had a significant correlation with the perioperative EF change. These findings indicated that patients with lower E′ had greater decrease in EF after surgery and that clinicians can predict postoperative LVD with a high sensitivity of 80% in patients with preoperative E′ value less than 6.5 cm/s. Figure 3 shows the additive value of E′ and preoperative EF and Ds for the prediction of postoperative LVD. In the case of patients with preoperative EF o 65%, Ds 4 32 mm, and E′ o 6.5 cm/s, the frequency of LVD after mitral valve repair was high (88.9%). Multivariate logistic regression analysis revealed that preoperative E′ value was an independent risk factor for LVD (odds ratio 1.98, 95% CI: 1.22-3.22). In patients with severe MR, left ventricular loading conditions are different, with a decreased afterload and an increased preload.1,23 Under these hemodynamic conditions, it has been indicated that EF decreases after mitral valve repair.24,25 Previous studies3,26 have shown that postoperative LVD with EF of o50% has a prognostic significance, and, therefore, the prevention of postoperative LVD is an issue of great importance. However, about 30% of the patients in this study still developed unexpected postoperative LVD. This indicated that the criteria for surgical intervention as per the current guidelines may be insufficient to prevent postoperative LVD. The authors’ study showed the clinical significance of preoperative E′ value in predicting postoperative LVD.
Fig 2. (A) E′, early diastolic mitral annular velocity; E, early diastolic transmitral velocity; EF, ejection fraction ROC analysis to evaluate the prognostic performance of E′, E/E′, and preoperative EF with regard to left ventricular dysfunction. The areas under the ROC curves were 0.777 for E′ and 0.711 for E/E′, which were significantly higher than those for preoperative EF value (p o 0.05). (B) E0 , early diastolic mitral annular velocity; Ds, left ventricular end-systolic diameter; MR, mitral regurgitation. ROC analysis to evaluate the prognostic performance of E0 , Ds, and, MR volume with regard to left ventricular dysfunction. The areas under the ROC curves were 0.691 for Ds and 0.652 for E/E0 , both of which were statistically significant (p o 0.05).
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Fig 3. EF, ejection fraction; Ds, left ventricular end-systolic diameter; E0 , early diastolic mitral annular velocity. Frequency of postoperative left ventricular dysfunction (LVD) according to preoperative EF, Ds, and E0 values. The incidence of postoperative LVD was 33.3% when preoperative EF was o65%. A combined analysis revealed that the occurrence of postoperative LVD was 44.4% at a preoperative EF of o65% and Ds of 432 mm and 88.9% at preoperative EF of o65%, Ds 4 32 mm, and E′ o 6.5 cm/s (p for trend ¼ 0.006).
Recent studies have shown that the preoperative values of Ds, EF, MR volume, and Tei index are good predictors of postoperative LVD after mitral valve repair.4–7 Yamano et al6 have shown that among 174 patients undergoing mitral valve repair, 52 (30%) developed postoperative LVD (EF o 50%), and Doppler-derived preoperative MR volume and Ds were powerful predictors of unexpected postoperative LVD. These data are consistent with the authors’ results. In their study, ROC analysis revealed that Ds and MR volume could predict postoperative LVD. Takasaki et al4 have shown that 37 (34%) of 108 patients surgery had postoperative LVD after MR surgery. They also indicated that preoperative Tei index 40.5 could predict postoperative LVD with high sensitivity and specificity (89% and 85%, respectively). The Tei index has been shown to have good correlation with E′ in patients with Table 2. Multivariate Logistic Regression Model for Left Ventricular Dysfunction (Yes/No): N ¼ 63; Left Ventricular Dysfunction ¼ 20 (31.7%) Factor
Age (yr) Gender (M/F) BMI (kg/m2) Preoperative EF (%) E′ (cm/sec) E/E′ LV end-systolic diameter (mm) MR regurgitation volume (mL)
Odds Ratio
95% CI
p Value
1.03 1.14 0.94 1.02 0.56 1.04 1.12 1.02
0.97-1.10 0.21-6.02 0.75-1.19 0.86-1.20 0.33-0.96 0.90-1.19 0.98-1.27 0.96-1.09
0.354 0.880 0.627 0.839 0.034* 0.616 0.101 0.489
Abbreviations: BMI, body mass index; CI, confidence interval; E, peak mitral valve early diastolic velocity; E′, tissue Doppler peak early diastolic myocardial velocity ratio; EF, ejection fraction; LV, left ventricle; MR, mitral regurgitation. *NOTE. p o 0.05 statistically significant.
diastolic dysfunction.27 Therefore, these results are supportive of the authors’ hypothesis. Tissue-Doppler-derived E′ is the velocity of the mitral annulus in the early diastolic period, and it represents the intrinsic speed of myocardial relaxation. E′ reflects diastolic function, but not systolic function.28 However, previous studies have indicated that E′ was a good predictor of cardiac mortality in patients with both preserved systolic function and systolic dysfunction.18,19,29,30 Yamamoto et al19 studied 96 patients with left ventricular systolic dysfunction and showed that the E′ value was a sensitive index of cardiac death or hospitalization for heart failure compared with other echocardiographic variables. This is because diastolic dysfunction often precedes systolic dysfunction, and, consequently, the E′ value also can reflect the degree of progression of the cardiac diseases. In this study, Figure 3 also could be interpreted as patients with coexisting systolic as well as diastolic dysfunction having a higher incidence of systolic dysfunction postoperatively. In MR patients, myocardial damage has occurred, which is not shown by systolic indices. Therefore, the authors anticipate that E′ can predict unexpected LV dysfunction after surgical correction of MR. The E/E′ ratio can predict the left ventricular filling pressure even in patients with lower EF, and it is associated with increased mortality and morbidity in patients with cardiac surgery.28 ROC analysis in this study revealed that both E′ and E/E′ were good predictors of postoperative LVD, whereas the multivariate logistic regression analysis showed that preoperative E′ value was an independent risk factor of postoperative LVD, and the E/E′ was not. Cardiac preload has an effect on the accuracy of the E value in predicting diastolic function.31 In the presence of MR, the loading conditions are modified, and this may affect the E value measurements. However, the E′ value is less affected by cardiac preload,31 and, therefore, it would become a good predictor of LVD after MR surgery. Considering this, the measurement of E′ is a suitable approach for detection of postoperative LVD. The authors’ study had some limitations. First, they included patients with atrial fibrillation. In these patients, the cardiac output changes in every cardiac cycle, which can affect their results. The average of 5 cardiac cycles was considered for all measurements in atrial fibrillation patients; this would have minimized the influence of the variability in cardiac output. Second, when measuring E′, the authors focused on the septal site of the mitral annulus; but for the accurate measurement of E′, the average of 6 segments should be measured.31 With a view to adopting a simplified approach in the perioperative period, the E′ value in the septal site was measured. Third, the authors did not measure tissue Dopplerderived measures of systolic function such as systolic myocardial velocity (S′). As indicated in the past study, S′ is an easy means of estimating left ventricular ejection fraction.28 However, in MR patients, S′ may be overestimated by the decreased left ventricular overload. So, this may not affect their results so much. Fourth, the authors did not measure the same echocardiographic parameters using transesophageal echocardiography during surgery. Fifth, their results only applied to patients with good left ventricular function (EF 4 50%) presenting for mitral valve surgery. The correlation between preoperative E′
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DETECTION OF LEFT VENTRICULAR DYSFUNCTION
and postoperative left ventricular function remained unknown in patients with EF o 50%. Sixth, their patients were studied at a short interval postoperatively (9 days), and whether postoperative LVD persists later was not known. Despite these limitations, the authors’ results suggested that the preoperative E′ value was useful for the detection of LVD after mitral valve surgery in severe MR patients.
CONCLUSIONS
The preoperative E′ value was found to be an independent risk factor for postoperative LVD after mitral valve surgery in patients with severe MR. The preoperative E′ value appeared to be useful in predicting the incidence of postoperative LVD more reliably than the other echocardiographic variables.
REFERENCES 1. Eckberg DL, Gault JH, Bouchard RL, et al: Mechanics of left ventricular contraction in chronic severe mitral regurgitation. Circulation 47:1252-1259, 1973 2. Starling MR, Kirsh MM, Montgomery DG, et al: Impaired left ventricular contractile function in patients with long-term mitral regurgitation and normal ejection fraction. J Am Coll Cardiol 22: 239-250, 1993 3. Crawford MH, Souchek J, Oprian CA, et al: Determinants of survival and left ventricular performance after mitral valve replacement. Department of Veterans Affairs Cooperative Study on Valvular Heart Disease. Circulation 81:1173-1181, 1990 4. Takasaki K, Gillinov AM, Yamano T, et al: Detection of left ventricular dysfunction with Tei index in normal ejection fraction patients with mitral regurgitation before mitral valve surgery. Am J Cardiol 103:1011-1014, 2009 5. Tribouilloy C, Rusinaru D, Szymanski C, et al: Predicting left ventricular dysfunction after valve repair for mitral regurgitation due to leaflet prolapse: Additive value of left ventricular end-systolic dimension to ejection fraction. Eur J Echocardiogr 12:702-710, 2011 6. Yamano T, Gillinov AM, Wada N, et al: Doppler-derived preoperative mitral regurgitation volume predicts postoperative left ventricular dysfunction after mitral valve repair. Am Heart J 157: 875-882, 2009 7. Mabrouk-Zerguini N, Léger P, Aubert S, et al: Tei index to assess perioperative left ventricular systolic function in patients undergoing mitral valve repair. Br J Anaesth 101:479-485, 2008 8. Troughton RW, Prior DL, Frampton CM, et al: Usefulness of tissue Doppler and color M-mode indexes of left ventricular diastolic function in predicting outcomes in systolic left ventricular heart failure (from the ADEPT study). Am J Cardiol 96:257-262, 2005 9. Olson JM, Samad BA, Alam M: Prognostic value of pulse-wave tissue Doppler parameters in patients with systolic heart failure. Am J Cardiol 102:722-725, 2008 10. Dini FL, Conti U, Fontanive P, et al: Prognostic value of Nterminal pro-type-B natriuretic peptide and Doppler left ventricular diastolic variables in patients with chronic systolic heart failure stabilized by therapy. Am J Cardiol 102:463-468, 2008 11. Dokainish H, Zoghbi WA, Lakkis NM, et al: Incremental predictive power of B-type natriuretic peptide and tissue Doppler echocardiography in the prognosis of patients with congestive heart failure. J Am Coll Cardiol 45:1223-1226, 2005 12. Hillis GS, Møller JE, Pellikka PA, et al: Noninvasive estimation of left ventricular filling pressure by E/e′ is a powerful predictor of survival after acute myocardial infarction. J Am Coll Cardiol 43: 360-367, 2004 13. Møller JE, Søndergaard E, Poulsen SH, et al: Color M-mode and pulsed wave tissue Doppler echocardiography: Powerful predictors of cardiac events after first myocardial infarction. J Am Soc Echocardiogr 14:757-763, 2001 14. Wang AY, Wang M, Lam CW, et al: Left ventricular filling pressure by Doppler echocardiography in patients with end-stage renal disease. Hypertension 52:107-114, 2008
15. Sturgess DJ, Marwick TH, Joyce C, et al: Prediction of hospital outcome in septic shock: A prospective comparison of tissue Doppler and cardiac biomarkers. Crit Care 14:R44, 2010 16. Imai H, Kurokawa S, Taneoka M, et al: Tissue Doppler imaging is useful for predicting the need for inotropic support after cardiac surgery. J Anesth 25:805-811, 2011 17. Iwabuchi Y, Ogawa T, Inoue T, et al: Elevated E/E′ predicts cardiovascular events in hemodialysis patients with preserved systolic function. Intern Med 51:155-160, 2012 18. Almeida P, Rodrigues J, Lourenço P, et al: Prognostic significance of applying the European Society of Cardiology consensus algorithm for heart failure with preserved systolic function diagnosis. Clin Cardiol 35:770-776, 2012 19. Yamamoto T, Oki T, Yamada H, et al: Prognostic value of the atrial systolic mitral annular motion velocity in patients with left ventricular systolic dysfunction. J Am Soc Echocardiogr 16: 333-339, 2003 20. Lang RM, Bierig M, Devereux RB, et al: Recommendations for chamber quantification: A report from the American Society of Echocardiography’s Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology. J Am Soc Echocardiogr 18: 1440-1463, 2005 21. Okada K, Mikami T, Kaga S, et al: Early diastolic mitral annular velocity at the interventricular septal annulus correctly reflects left ventricular longitudinal myocardial relaxation. Eur J Echocardiogr 12: 917-923, 2011 22. American College of Cardiology; American Heart Association Task Force on Practice Guidelines (Writing Committee to revise the 1998 guidelines for the management of patients with valvular heart disease); Society of Cardiovascular Anesthesiologists, Bonow RO, Carabello BA, Chatterjee K, et al: ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing Committee to Revise the 1998 guidelines for the management of patients with valvular heart disease) developed in collaboration with the Society of Cardiovascular Anesthesiologists endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons. J Am Coll Cardiol 48:e1-148, 2006. 23. Braunwald E: Mitral regurgitation: Physiologic, clinical, and surgical considerations. N Engl J Med 281:425-433, 1969 24. Okita Y, Miki S, Ueda Y, et al: Comparative evaluation of left ventricular performance after mitral valve repair or valve replacement with or without chordal preservation. J Heart Valve Dis 2:159-166, 1993 25. Wisenbaugh T: Does normal pump function belie muscle dysfunction in patients with chronic severe mitral regurgitation? Circulation 77:515-525, 1988 26. Enriquez-Sarano M, Tajik AJ, Schaff HV, et al: Echocardiographic prediction of left ventricular function after correction of mitral regurgitation: Results and clinical implications. J Am Coll Cardiol 24:1536-1543, 1994
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27. Greco S, Troisi F, Brunetti ND, et al: Tei index correlates with tissue Doppler parameters and reflects neurohormonal activation in patients with an abnormal transmitral flow pattern. Echocardiography 26:1012-1018, 2009 28. Jun NH, Shim JK, Kim JC, et al: Prognostic value of a tissue Doppler-derived index of left ventricular filling pressure on composite morbidity after off-pump coronary artery bypass surgery. Br J Anaesth 107:519-524, 2011 29. Wang M, Yip GW, Wang AY, et al: Peak early diastolic mitral annulus velocity by tissue Doppler imaging adds indepen-
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dent and incremental prognostic value. J Am Coll Cardiol 41: 820-826, 2003 30. Wang M, Yip G, Yu CM, et al: Independent and incremental prognostic value of early mitral annulus velocity in patients with impaired left ventricular systolic function. J Am Coll Cardiol 45: 272-277, 2005 31. Skubas N: Intraoperative Doppler tissue imaging is a valuable addition to cardiac anesthesiologists’ armamentarium: A core review. Anesth Analg 108:48-66, 2009
C
HRONIC MITRAL REGURGITATION (MR) can lead to left ventricular dysfunction (LVD) and heart failure. The optimal timing of surgical intervention is, thus, very important. In cardiac surgery patients, ejection fraction (EF), as measured by echocardiography, is the most commonly used parameter for assessing left ventricular function. However, EF is considered unreliable in patients with MR.1–3 In these patients, left ventricular systolic function often is overestimated by ejection indices, and EF often remains normal. This is because, in the presence of MR, the left ventricle ejects toward both the left atrium (low impedance) and aorta, thereby decreasing the left ventricular afterload. Therefore, an unsuspected LVD after mitral valve repair often occurs at an incidence of 15% to 34%.4–6 Under these circumstances, an index for predicting LVD would be useful. Recent studies have shown that indices such as Tei index, MR volume, and left ventricular end-systolic diameter (Ds) are good predictors of LVD after mitral valve repair in patients with severe MR.4–7 Tissue Doppler imaging (TDI), a comparatively new method for measuring myocardial velocity by echocardiography, has been used to assess systolic and diastolic function and has shown prognostic utility in patients with heart failure,8–11 myocardial infarction,12,13 and end-stage renal disease.14 Studies also have shown that early diastolic mitral annular velocity (E′), as measured by TDI, reflects left ventricular diastolic function and predicts the hospital outcome in critically ill patients.15–17 E′ is reported to be a good predictor of cardiac events (heart failure, cardiac death) in patients with both preserved systolic function and systolic dysfunction,18,19 and also reflects the degree of progression of the cardiac diseases. Therefore, the authors anticipated that E′ can predict unexpected LVD after surgical correction of MR. This study aimed at determining whether the preoperative E′ value measured by transthoracic echocardiography (TTE) was associated with left ventricular myocardial dysfunction after mitral valve repair in patients with severe MR.
the ROC curve was 0.777 (95% confidence interval [CI]: 0.6440.911) for E′, and the optimal threshold value of E′ for predicting LVD was 6.5 cm/s (sensitivity, 80%; specificity, 67.4%). The frequency of LVD was 33.3% for a preoperative EF o 65%; 44.4% for preoperative EF o 65% and left ventricular end-systolic diameter 432 mm; and 88.9% for preoperative EF o 65%, left ventricular end-systolic diameter 432 mm, and E′ o 6.5 cm/s (p ¼ 0.006). Multivariate logistic regression models analysis revealed that E′ was an independent risk factor for LVD (odds ratio: 1.98, 95% CI: 1.22-3.22). Conclusions: Preoperative E′ value was an independent risk factor of LVD after mitral valve repair in patients with severe MR. & 2014 Elsevier Inc. All rights reserved. KEY WORDS: mitral regurgitation, early diastolic mitral annular velocity, left ventricular dysfunction, mitral valve repair
SUBJECTS AND METHODS The authors obtained approval from the ethics committee of their hospital. The patients who underwent mitral valve repair for chronic severe MR between May 2007 and December 2012 were retrospectively enrolled in this study. They excluded patients with aortic regurgitation and stenosis of more than mild degree, mitral stenosis of any degree, and preoperative LVD (preoperative EF of o50%). The Philips echocardiography machine iE33 (Philips Medical Systems, Bothell, WA) was used. All echocardiographic data in this study were obtained by TTE. Standard 2-dimensional and Doppler TTE were performed by cardiologists in the authors’ institution before (15 ⫾ 9.1 days) and after (9.0 ⫾ 2.1 days) surgery. The clinicians who analyzed the echo images were blinded to further clinical information. Left ventricular EF was measured by the Simpson disk method,20 and postoperative LVD was defined by a postoperative EF of o50%. MR volume was measured using the proximal isovelocity surface area or quantitative Doppler method. In patients with tricuspid regurgitation, continuous-wave Doppler was used to measure the maximum regurgitation velocity, and the pulmonary artery systolic pressure was calculated using the simplified Bernoulli equation, assuming the right atrial pressure was 10 mmHg. Early diastolic mitral annular velocity was measured by pulse-wave TDI. The sample volume was set at the septal mitral annulus in the four-chamber view. The E′ value at the septal annulus was found to be more useful in evaluating left ventricular diastolic function than that of the lateral annulus.21 Transmitral flow was obtained using pulse-wave Doppler at the tip of the mitral leaflets in the 4-chamber view. The ratio
From the Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka, Japan. Address reprint requests to Koichi Suehiro, MD, Osaka City University Graduate School of Medicine, Department of Anesthesiology, 1-5-7 Asahimachi, Abenoku, Osaka City, Osaka 545-8586, Japan. E-mail: [email protected] © 2014 Elsevier Inc. All rights reserved. 1053-0770/2601-0001$36.00/0 http://dx.doi.org/10.1053/j.jvca.2013.07.013
Journal of Cardiothoracic and Vascular Anesthesia, Vol 28, No 1 (February), 2014: pp 25–30
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SUEHIRO ET AL
of early diastolic transmitral velocity (E) to E′ was calculated. In patients with atrial fibrillation, averages of 5 cardiac cycles were calculated for all measurements at the end-expiration period. In patients with sinus rhythm, all echocardiographic variables were measured for 3 cardiac cycles, and the average values were calculated. General anesthesia was induced with midazolam (0.1 mg/kg), propofol (1 mg/kg), fentanyl (2 to 5 μg/kg), and rocuronium (0.8 to 1 mg/kg) and maintained using sevoflurane (1.0 to 2.0%), fentanyl (20 to 40 μg/kg per case), and rocuronium (15 to 30 mg/h). The authors controlled the depth of anesthesia at BIS values (measured using BIS monitor v. 4.0, Aspect Medical System, Natick, MA) between 40 and 60. During cardiopulmonary bypass (CPB), propofol was administered continuously (2 to 3 mg/kg/h) to maintain general anesthesia. After induction of general anesthesia, an arterial pressure catheter was inserted into the radial artery in addition to inserting a central venous catheter and a thermodilution pulmonary artery catheter into the right internal jugular vein. The authors performed standard CPB procedures in all patients. Standard flow rates of 2.4 to 2.6 L/min/m2 were obtained to maintain the mean arterial pressure between 50 and 80 mmHg. Alpha-stat management was used to maintain PaCO2 at Z40 mmHg and hematocrit at 422%. Mild hypothermia was maintained with a rectal temperature of 321C, and both anterograde and retrograde crystalloid cardioplegia were used. The most common surgical technique for anterior leaflet prolapse was repair of the chords, and posterior leaflet prolapse usually was repaired by the resection and suture technique. In all cases, an annuloplasty ring (Edwards Lifesciences, Irvine, CA) was used. All procedures were performed by the same surgical team. The endpoint of the authors’ study was the occurrence of postoperative LVD. Postoperative LVD was defined by a postoperative EF of o50%. They divided the patients into 2 groups according to the postoperative EF (D group, postoperative EF o 50%; N group, postoperative EF Z 50%). Intergroup comparison was made in terms of perioperative characteristics. To determine the threshold of the preoperative E′ value in predicting postoperative LVD, the authors performed a receiver operating characteristic (ROC) analysis to investigate the prognostic performance of preoperative echocardiographic value of E′, E/E′, EF, Ds, and MR volume with regard to postoperative LVD (EF o 50%). As per the American College of Cardiology (ACC)/ American Heart Association (AHA) guidelines,22 mitral valve surgery is recommended for patients with early signs of LVD (Ds of Z40 mm or EF of r60%). Therefore, the authors investigated the incidence of postoperative LVD on the basis of preoperative EF, Ds, and E′ values. The cut-off values were determined by ROC analysis. Separate multivariate logistic regression models were used to examine the independent effects of the preoperative echocardiographic variables on the risk of postoperative LVD. All results were expressed as mean and standard deviation unless otherwise indicated. Statistical analysis was performed using Sigma Plot 11.2 (Systat Software Inc., San Jose, CA). The authors used the Student’s t-test, χ2 test, and Mann-Whitney U test to compare the demographic data. For all analyses, a p value of o0.05 was considered significant. RESULTS
Eighty patients were enrolled in this study. Seventeen patients were excluded (8 patients with preoperative EF o 50% and 9 patients with aortic valve disease), and the final study population comprised 63 patients (24 women and 39 men). Valvular prolapse or flail involved the anterior leaflet in 11 patients (17%), posterior leaflet in 40 patients (63%), and both leaflets in 12 patients (19%). All patients had less than mild MR after surgery. Perioperative characteristics of the studied patients are shown in Table 1. Postoperative LVD occurred in 20 patients (31.7%). The D and N groups showed significant differences in
Ds, E′, and E/E′ (p o 0.05). Results of correlation analysis between preoperative E′ value and perioperative EF change are shown in Figure 1. The preoperative E′ value was correlated significantly with perioperative EF change (p ¼ 0.019, r ¼ 0.293). ROC analysis was performed to evaluate the prognostic performance of E′, E/E′, preoperative EF, Ds, and MR volume with regard to postoperative LVD (Fig 2A, 2B). The areas under the ROC curves were 0.777 (95% confidence interval [CI]: 0.644-0.911) for E′ and 0.711 (95% CI: 0.577-0.844) for E/E′, which were significantly higher than those for preoperative EF value (p o 0.05) (preoperative EF: 0.523, 95% CI: 0.359-0.686) (Fig 2A). In Figure 2B, the areas under the ROC curves were 0.691 (95% CI: 0.536-0.847) for Ds and 0.652 (95% CI: 0.513-0.790) for E/E′, both of which were statistically significant (p o 0.05). The optimal threshold value of E0 in predicting postoperative LVD was 6.5 cm/s (sensitivity, 80%; specificity, 67.4%). Figure 3 shows the incidence of postoperative LVD determined on the basis of preoperative EF, Ds, and E′ values. The incidence Table 1. Perioperative Characteristics in Studied Patients
Age (yr) Gender (M/F) Height (cm) Body weight (kg) NYHA classification I/II/III/IV Preoperative complication Hypertension, n (%) Diabetes mellitus, n (%) Atrial fibrillation, n (%) Angina, n (%) Echocardiography data Preoperative LV EF (%) Prolapse Anterior/Posterior leaflet Both leaflets LV end-diastolic diameter (mm) LV end-systolic diameter (mm) E (cm/s) E′ (cm/s) E / E′ E-wave deceleration time (ms) MR regurgitation volume (mL) Systolic PAP (mmHg) Anesthesia time (min) Surgery time (min) CPB time (min) Cross-clamp time (min)
D group
N group
(n ¼ 20)
(n ¼ 43)
65.3 ⫾ 12.5 65.5 ⫾ 10.9 13/10 26/14 159 ⫾ 11.2 161 ⫾ 9.9 54.9 ⫾ 15.0 57.8 ⫾ 11.6 2/11/7/0 12/26/5/0 12 1 6 1
(60) (5.0) (30) (5.0)
19 4 13 1
(44) (9.3) (30) (2.3)
p Value
0.927 0.505 0.458 0.451 0.06 0.243 0.556 0.985 0.573
64.4 ⫾ 5.8
64.8 ⫾ 4.8
0.775
4/13 3 58.2 ⫾ 6.8
7/27 9 54.7 ⫾ 7.7
0.835
35.3 ⫾ 8.5
30.7 ⫾ 5.6
0.035*
120 ⫾ 5.69 ⫾ 21.8 ⫾ 194 ⫾ 71.8 ⫾ 43.2 ⫾ 342 ⫾ 277 ⫾ 175 ⫾ 130 ⫾
117 7.21 16.9 206 65.3 41.3 350 279 173 136
37.2 1.67 7.43 58.5 14.9 14.8 70.1 62.0 42.7 33.1
⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾ ⫾
0.09
37.0 0.755 1.54 p o 0.001* 5.63 0.005* 38.3 0.438 13.2 0.09 15.0 0.645 62.8 0.661 54.0 0.924 38.3 0.841 35.1 0.532
NOTE. Data are expressed as mean ⫾ SD. D group: patients with postoperative EF o 50%, N group: patients with postoperative EF Z 50%. Abbreviations: CPB, cardiopulmonary bypass; E, peak mitral valve early diastolic velocity; E′, tissue Doppler peak early diastolic myocardial velocity; EF, ejection fraction; LV, left ventricle; MR, mitral regurgitation; NYHA, New York Heart Association; PAP, pulmonary artery pressure. *p o 0.05 statistically significant.
DETECTION OF LEFT VENTRICULAR DYSFUNCTION
Fig 1. E0 , early diastolic mitral annular velocity; EF, ejection fraction. Correlation analysis between preoperative E′ value and perioperative EF change. The preoperative E′ value was correlated significantly with perioperative EF change (p ¼ 0.019, r ¼ 0.293).
of postoperative LVD was 33.3% when preoperative EF was o65%. A combined analysis revealed that the occurrence of postoperative LVD was 44.4% at a preoperative EF of o65% and Ds of 432 mm and 88.9% at preoperative EF of o65%, Ds 432 mm, and E′ o6.5 cm/s (p for trend ¼ 0.006). The authors used multivariate logistic regression models to examine the independent effects of preoperative echocardiographic variables on the risk of developing postoperative LVD, which are shown in Table 2. Preoperative E′ value was an independent risk factor of LVD after mitral valve repair in patients with severe MR. DISCUSSION
This is the first published study on the correlation between preoperative E′ value and postoperative LVD after mitral valve repair in patients with severe MR. ROC analysis showed that
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preoperative E′ value was a better predictor of postoperative LVD than the preoperative echocardiographic values of EF, E/ E′, Ds, and MR volume, and the optimal threshold value for E′ was 6.5 cm/s with a sensitivity of 80% and specificity of 67.4%. As shown in Figure 1, the preoperative E′ value also had a significant correlation with the perioperative EF change. These findings indicated that patients with lower E′ had greater decrease in EF after surgery and that clinicians can predict postoperative LVD with a high sensitivity of 80% in patients with preoperative E′ value less than 6.5 cm/s. Figure 3 shows the additive value of E′ and preoperative EF and Ds for the prediction of postoperative LVD. In the case of patients with preoperative EF o 65%, Ds 4 32 mm, and E′ o 6.5 cm/s, the frequency of LVD after mitral valve repair was high (88.9%). Multivariate logistic regression analysis revealed that preoperative E′ value was an independent risk factor for LVD (odds ratio 1.98, 95% CI: 1.22-3.22). In patients with severe MR, left ventricular loading conditions are different, with a decreased afterload and an increased preload.1,23 Under these hemodynamic conditions, it has been indicated that EF decreases after mitral valve repair.24,25 Previous studies3,26 have shown that postoperative LVD with EF of o50% has a prognostic significance, and, therefore, the prevention of postoperative LVD is an issue of great importance. However, about 30% of the patients in this study still developed unexpected postoperative LVD. This indicated that the criteria for surgical intervention as per the current guidelines may be insufficient to prevent postoperative LVD. The authors’ study showed the clinical significance of preoperative E′ value in predicting postoperative LVD.
Fig 2. (A) E′, early diastolic mitral annular velocity; E, early diastolic transmitral velocity; EF, ejection fraction ROC analysis to evaluate the prognostic performance of E′, E/E′, and preoperative EF with regard to left ventricular dysfunction. The areas under the ROC curves were 0.777 for E′ and 0.711 for E/E′, which were significantly higher than those for preoperative EF value (p o 0.05). (B) E0 , early diastolic mitral annular velocity; Ds, left ventricular end-systolic diameter; MR, mitral regurgitation. ROC analysis to evaluate the prognostic performance of E0 , Ds, and, MR volume with regard to left ventricular dysfunction. The areas under the ROC curves were 0.691 for Ds and 0.652 for E/E0 , both of which were statistically significant (p o 0.05).
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Fig 3. EF, ejection fraction; Ds, left ventricular end-systolic diameter; E0 , early diastolic mitral annular velocity. Frequency of postoperative left ventricular dysfunction (LVD) according to preoperative EF, Ds, and E0 values. The incidence of postoperative LVD was 33.3% when preoperative EF was o65%. A combined analysis revealed that the occurrence of postoperative LVD was 44.4% at a preoperative EF of o65% and Ds of 432 mm and 88.9% at preoperative EF of o65%, Ds 4 32 mm, and E′ o 6.5 cm/s (p for trend ¼ 0.006).
Recent studies have shown that the preoperative values of Ds, EF, MR volume, and Tei index are good predictors of postoperative LVD after mitral valve repair.4–7 Yamano et al6 have shown that among 174 patients undergoing mitral valve repair, 52 (30%) developed postoperative LVD (EF o 50%), and Doppler-derived preoperative MR volume and Ds were powerful predictors of unexpected postoperative LVD. These data are consistent with the authors’ results. In their study, ROC analysis revealed that Ds and MR volume could predict postoperative LVD. Takasaki et al4 have shown that 37 (34%) of 108 patients surgery had postoperative LVD after MR surgery. They also indicated that preoperative Tei index 40.5 could predict postoperative LVD with high sensitivity and specificity (89% and 85%, respectively). The Tei index has been shown to have good correlation with E′ in patients with Table 2. Multivariate Logistic Regression Model for Left Ventricular Dysfunction (Yes/No): N ¼ 63; Left Ventricular Dysfunction ¼ 20 (31.7%) Factor
Age (yr) Gender (M/F) BMI (kg/m2) Preoperative EF (%) E′ (cm/sec) E/E′ LV end-systolic diameter (mm) MR regurgitation volume (mL)
Odds Ratio
95% CI
p Value
1.03 1.14 0.94 1.02 0.56 1.04 1.12 1.02
0.97-1.10 0.21-6.02 0.75-1.19 0.86-1.20 0.33-0.96 0.90-1.19 0.98-1.27 0.96-1.09
0.354 0.880 0.627 0.839 0.034* 0.616 0.101 0.489
Abbreviations: BMI, body mass index; CI, confidence interval; E, peak mitral valve early diastolic velocity; E′, tissue Doppler peak early diastolic myocardial velocity ratio; EF, ejection fraction; LV, left ventricle; MR, mitral regurgitation. *NOTE. p o 0.05 statistically significant.
diastolic dysfunction.27 Therefore, these results are supportive of the authors’ hypothesis. Tissue-Doppler-derived E′ is the velocity of the mitral annulus in the early diastolic period, and it represents the intrinsic speed of myocardial relaxation. E′ reflects diastolic function, but not systolic function.28 However, previous studies have indicated that E′ was a good predictor of cardiac mortality in patients with both preserved systolic function and systolic dysfunction.18,19,29,30 Yamamoto et al19 studied 96 patients with left ventricular systolic dysfunction and showed that the E′ value was a sensitive index of cardiac death or hospitalization for heart failure compared with other echocardiographic variables. This is because diastolic dysfunction often precedes systolic dysfunction, and, consequently, the E′ value also can reflect the degree of progression of the cardiac diseases. In this study, Figure 3 also could be interpreted as patients with coexisting systolic as well as diastolic dysfunction having a higher incidence of systolic dysfunction postoperatively. In MR patients, myocardial damage has occurred, which is not shown by systolic indices. Therefore, the authors anticipate that E′ can predict unexpected LV dysfunction after surgical correction of MR. The E/E′ ratio can predict the left ventricular filling pressure even in patients with lower EF, and it is associated with increased mortality and morbidity in patients with cardiac surgery.28 ROC analysis in this study revealed that both E′ and E/E′ were good predictors of postoperative LVD, whereas the multivariate logistic regression analysis showed that preoperative E′ value was an independent risk factor of postoperative LVD, and the E/E′ was not. Cardiac preload has an effect on the accuracy of the E value in predicting diastolic function.31 In the presence of MR, the loading conditions are modified, and this may affect the E value measurements. However, the E′ value is less affected by cardiac preload,31 and, therefore, it would become a good predictor of LVD after MR surgery. Considering this, the measurement of E′ is a suitable approach for detection of postoperative LVD. The authors’ study had some limitations. First, they included patients with atrial fibrillation. In these patients, the cardiac output changes in every cardiac cycle, which can affect their results. The average of 5 cardiac cycles was considered for all measurements in atrial fibrillation patients; this would have minimized the influence of the variability in cardiac output. Second, when measuring E′, the authors focused on the septal site of the mitral annulus; but for the accurate measurement of E′, the average of 6 segments should be measured.31 With a view to adopting a simplified approach in the perioperative period, the E′ value in the septal site was measured. Third, the authors did not measure tissue Dopplerderived measures of systolic function such as systolic myocardial velocity (S′). As indicated in the past study, S′ is an easy means of estimating left ventricular ejection fraction.28 However, in MR patients, S′ may be overestimated by the decreased left ventricular overload. So, this may not affect their results so much. Fourth, the authors did not measure the same echocardiographic parameters using transesophageal echocardiography during surgery. Fifth, their results only applied to patients with good left ventricular function (EF 4 50%) presenting for mitral valve surgery. The correlation between preoperative E′
29
DETECTION OF LEFT VENTRICULAR DYSFUNCTION
and postoperative left ventricular function remained unknown in patients with EF o 50%. Sixth, their patients were studied at a short interval postoperatively (9 days), and whether postoperative LVD persists later was not known. Despite these limitations, the authors’ results suggested that the preoperative E′ value was useful for the detection of LVD after mitral valve surgery in severe MR patients.
CONCLUSIONS
The preoperative E′ value was found to be an independent risk factor for postoperative LVD after mitral valve surgery in patients with severe MR. The preoperative E′ value appeared to be useful in predicting the incidence of postoperative LVD more reliably than the other echocardiographic variables.
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27. Greco S, Troisi F, Brunetti ND, et al: Tei index correlates with tissue Doppler parameters and reflects neurohormonal activation in patients with an abnormal transmitral flow pattern. Echocardiography 26:1012-1018, 2009 28. Jun NH, Shim JK, Kim JC, et al: Prognostic value of a tissue Doppler-derived index of left ventricular filling pressure on composite morbidity after off-pump coronary artery bypass surgery. Br J Anaesth 107:519-524, 2011 29. Wang M, Yip GW, Wang AY, et al: Peak early diastolic mitral annulus velocity by tissue Doppler imaging adds indepen-
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