ARTICLE IN PRESS doi:10.1510/icvts.2010.262303 Editorial
www.icvts.org
Institutional report - Valves
Per Lindqvista,b,*, Ying Zhaob,d, Gani Bajraktarie, Anders Holmgrena,c, Michael Y. Heneina,b
Abstract
Nomenclature Historical Pages Brief Case Report Communication
We studied 28 consecutive patients (age 64"10 years, 17 males) with severe AS based on a peak aortic gradient of )70 mmHg andyor aortic valve area -1.0 cm2, who were referred to the Heart Centre of Umea ˚ University Hospital for AVR. The studied group is part of a previously studied cohort of AS patients w3x. Patients were examined the day before and six months after surgery using Doppler echocardiography including tissue Doppler technique. All patients had undergone cardiac catheterization before surgery to exclude significant ()50%) coronary artery stenosis. Patients were excluded if they had impaired LV systolic function (EF -50%), signs of raised left atrial pressure (EyA)2 andyor short isovolumic relaxation time -40 ms), signs of pulmonary hypertension (RV–RA peak drop )40 mmHg) or were preoperatively not in sinus rhythm. Patients with more than mild additional valve disease, chronic obstructive pulmonary disease (FEV1 yEVC -70%) or renal failure (creatinine )150 mmolyl) were also excluded. A
Best Evidence Topic
䊚 2011 Published by European Association for Cardio-Thoracic Surgery
2.1. Study population
State-of-the-art
夞 This study was supported by the faculty of medicine, Umea ˚ University, Swedish Heart and Lung Foundation, and the Heart Foundation of Northern Sweden. *Corresponding author. Tel.: q46-90-7851965; fax: q46-90-137633. E-mail address:
[email protected] (P. Lindqvist).
2. Methods
Follow-up Paper
Aortic stenosis (AS) causes various degrees of left ventricular (LV) abnormalities including hypertrophy as well as systolic and diastolic dysfunction, particularly involving the subendocardium with its consequence on longitudinal function. Although LV ejection fraction (EF) plays a critical role in the clinical decision-making in these patients, it may remain within normal range despite significant abnormalities of other functional parameters w1, 2x. We have previously shown that LV longitudinal velocities and strain are reduced in such patients, as early signs of LV systolic dysfunction, before EF is affected w3x. We have also shown that the reduced LV long axis function improves early after aortic valve replacement (AVR), even before mass regression w3x. As LVEF and cardiac output seem to remain unchanged after AVR, a third functional component must exist which should potentially compensate for the reduced long axis function. LV rotation function including twist is of significant value in maintaining the overall function w4x. The rotation pattern in AS has been studied by cardiac magnetic resonance w5x and speckle tracking echocardiography (STE) w6x and have shown exaggerated twist w5x, but
the effect of AVR on such changes remains unclear. The aim of this study was therefore to assess the relationship between LV rotation function and segmental and global function in AS patients as well as the effect of AVR on these relationships.
Negative Results
1. Introduction
Proposal for Bailout Procedure
Keywords: Aortic stenosis; Aortic valve replacement; Left ventricular function; Twist
ESCVS Article
The aim of this study was to assess the effect of aortic valve replacement (AVR) on left ventricular (LV) twist function. We studied 28 severe aortic stenosis (AS) patients with normal LV ejection fraction (EF) before and six months after AVR. LV long axis function was assessed using M-mode and tissue Doppler and twist function using speckle tracking echocardiography. The data were compared with 28 age and sex-matched normal controls. In patients, LVEF remained unchanged after AVR. LV long axis function was reduced before surgery but normalized after AVR. LV twist was increased before (19.7"5.78 vs. 12.9"3.28, P-0.001) and normalized after AVR (14.4"5.28, P-0.001). In normals, LV twist correlated with LV fractional shortening (rs0.81, P-0.001) but not with EF. This relationship was reversed in patients before (rs0.52, P-0.01) and after AVR (rs0.34, Psns). In patients with severe AS and normal EF, LV twist is exaggerated suggesting potential compensation for the reduced long axis function. These disturbances normalize within six months of AVR but lose their relationship with basal LV function. 䊚 2011 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.
Institutional Report
Received 30 November 2010; received in revised form 14 January 2011; accepted 18 January 2011
Protocol
a Heart Centre, Umea ˚ University, S-90185 Umea ˚, Sweden Departments of Public Health and Clinical Medicine, Umea ˚ University, Umea ˚, Sweden c Surgery and Perioperative Sciences, Umea ˚ University, Umea ˚, Sweden d Ultrasound Department, Beijing Anzhen Hospital, Capital Medical University, Beijing, China e Internal Medicine Clinic, University Clinical Centre of Kosova, Prishtina, Kosovo b
Work in Progress Report
Aortic valve replacement normalizes left ventricular twist function夞
New Ideas
Interactive CardioVascular and Thoracic Surgery 12 (2011) 701–706
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total of 28 age- and sex-matched healthy individuals (age 60"10 years, 13 males) randomly selected from the Umea ˚ population were also studied using the same Doppler echocardiographic protocol who served as controls, none of them had any cardiovascular risk or systemic disease. Patients and controls had given an informed consent to participate in the study, which was approved by the Local Ethics Committee of Umea ˚ University. 2.2. Echocardiographic examination Echocardiographic examination was performed using a Vivid 7 system (GE Medical Systems, Horten, Norway) equipped with an adult 1.5–4.3 MHz phased array transducer. Standard views from the parasternal long and shortaxis and apical four-chamber views were obtained. Measurements of LV dimensions were made using conventional recommendations w7x. LV filling and ejection flow velocities were obtained using pulsed and continuous wave Doppler techniques, respectively, as proposed by the American Society of Echocardiography w8x. LV longitudinal function was studied using M-mode and tissue Doppler techniques with the cursor placed at the septal and lateral angles of the mitral valve annulus and the sample volume (5 mm) at the basal annular level of the two segments, respectively. All recordings were made at a speed of 100 mmys with a superimposed ECG (lead II). Off-line analysis was made using a commercially available software system (General Electric, EchoPac version 5.0.1, Waukesha, WI, USA).
2. Peak early (E wave), E-wave deceleration time (EDT) and late (A wave) LV filling velocities were measured from the transmitral Doppler flow velocities and EyA was calculated. LV filling time was measured from the onset of the transmitral E wave to the end of A wave and corrected for RR interval. 3. Long axis measurements: LV long axis amplitude of motion was measured as previously described at the lateral and septal segments w11x. Long axis peak systolic (S9) and early diastolic (E9) myocardial velocities were measured from tissue Doppler recordings at basal lateral and septal segments, and EyE9 ratio was calculated with E9 taken from the lateral basal segment. 4. LV twist function: cavity twist was calculated as the net difference of peak systolic LV rotation between apical and basal short-axis planes w10x. 2.5. Statistical analysis Statistical analyses were made using a standard statistical software package (PASW statistics 18). Categorical variables were expressed as percentage (%). Normally distributed continuous data were expressed as mean"standard deviation (S.D.). The unpaired t-test was used to compare patients and controls. Paired t-test was used to compare pre- and postoperative data, and linear regression (Pearson’s coefficient) was performed to identify the correlations. A P-0.05 was considered as statistically significant. 3. Results
2.3. Left ventricular rotation functions Gray scale digital cine loops triggered to QRS complex were acquired from the two LV short-axis planes at the basal and apical levels for rotation measurements. Care was taken to ensure that the basal short-axis plane contained the mitral valve. The apical plane was acquired as previously described w9x. At each plane, three consecutive cardiac cycles were acquired during quiet breath-hold at a frame rate of approximately 70 fys, without using dual focus, and were stored on hard disk for off-line analysis using the commercially available software (EchoPAC PC 08, GE Healthcare, version 8). The off-line analysis was performed by a single observer, blinded to the clinical data. The region of interest (ROI) of the LV was set between the endocardial and epicardial borders, thus delineating the entire myocardial segmental circumference. The ROI width was adjusted as needed to fit the wall thickness, as previously described w10x. The tracking quality of each segment was indicated by the software, and segments with suboptimal tracking quality were excluded. Averaged apical and basal rotation data were used for calculating LV twist as previously proposed, from speckle tracking echocardiography (STE) w10x. 2.4. Measurements 1. LV fractional shortening (LVFS) was calculated as the percentage fall of LV systolic dimension with respect to diastolic dimension. LVEF was measured using biplane Simpson’s method.
The reproducibility of cardiac rotation measurements of our laboratory has been previously reported, being 5–19% w12x. Pre- and perioperative clinical data are shown in Table 1. ECG recordings showed QRS duration of 94"18 ms before and 93"18 ms after AVR (Psns). Twelve out of 28 patients proved to have bicuspid aortic valve during surgery. 3.1. Patients before AVR vs. controls Patients had normal EF (inclusion criterion) but had significant hypertrophy of the septal and posterior walls (P-0.001 for both) compared with controls. The LV dimensions and FS were not different from controls. LV EyA was Table 1. Pre- and perioperative clinical data of patients Patients (ns28) Heart rate (beatsymin) NYHA (1, 2, 3, 4) Pulmonary disease (%) Diabetes (%) Smoker (%) Hypertension (%) Stroke (%) Creatinine (mmolyl) ECC (min) OT (min) EuroSCORE
69"10 1, 15, 12, 0 0 (0) 4 (14.3) 8 (28.6) 19 (67.9) 3 (10.7) 78.6"17.4 91.6"31.6 70.3"18.5 4.2"2.2
Data presented as mean"S.D. NYHA, New York Heart Association clinical score; ECC, extracorporeal circulation time; OT, occlusion cross-clamping time.
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Table 2. Left ventricular conventional measures in controls and in patients before and after AVR P-value (pre- vs. post AVR)
65"8 0.93"0.16 0.82"0.16 5.1"0.4 3.0"0.5 64"8 36"5 65"19 65"15 9.0"3.0 1.09"0.29 197"66 8.8"2.9 54"5
69"10 1.51"0.24 1.28"0.18 5.1"0.6 3.0"0.5 68"9 38"7 76"22 87"20 6.8"2.3 0.91"0.25 251"72 12.3"4.3 50"5
ns -0.001 -0.001 ns ns ns ns ns -0.001 -0.01 -0.01 -0.01 -0.001 -0.01
70"11 1.29"0.30 1.10"0.22 4.8"0.6 2.8"0.5 69"5 43"5 74"19 84"20 10.0"2.5 0.95"0.20 244"73 9.0"2.7 51"6
ns -0.001 -0.001 ns ns ns -0.01 ns ns -0.001 ns ns -0.01 ns
Data are presented as mean"S.D. AVR, aortic valve replacement; HR, heart rate; IVST, interventricular septal thickness; PWT, posterior wall thickness; LV, left ventricle; EDD, end-diastolic dimension; ESD, end-systolic dimension; EF, ejection fraction; E, early diastolic filling velocity; A, late diastolic velocity; EDT, E wave deceleration time; E9, early diastolic myocardial velocity; FT, filling time; RR, RR interval; ns, not significant.
Institutional Report
Post AVR (ns28)
Protocol
P-value
Work in Progress Report
Pre AVR (ns28)
New Ideas
HR (beatsymin) IVST (cm) PWT (cm) LV EDD (cm) LV ESD (cm) LVEF (%) LVFS (%) E (cmys) A (cmys) E9 (cmys) EyA EDT (ms) EyE9 FTyRR (%)
Controls (ns28)
ESCVS Article
3.3. Relationship between components of LV function
Follow-up Paper
4. Discussion 3.2. Preoperative vs. 6 months post AVR 4.1. Findings
Controls (ns28)
P-value
Post AVR (ns28)
P-value (pre- vs. post AVR)
1.3"0.4 7.0"1.5 6.8"2.3 1.2"0.1 5.7"1.1 6.2"2.0
-0.05 -0.01 -0.01 -0.05 -0.05 ns
1.7"0.3 9.9"1.7 10.0"2.5 1.2"0.2 7.2"1.2 7.0"1.5
-0.001 -0.001 -0.001 -0.05 -0.001 ns
–5.3"2.5 7.6"2.6 12.9"3.2
–6.2"3.0 13.0"5.8 19.7"5.7
ns -0.001 -0.001
–5.8"2.7 8.6"4.6 14.4"5.2
ns -0.001 -0.001
Data are presented as mean"S.D. AVR, aortic valve replacement; S9, systolic myocardial velocity; E9, early diastolic myocardial velocity; ns, not significant.
Brief Case Report Communication
1.6"0.3 8.2"1.6 9.0"3.0 1.5"0.3 7.0"1.2 7.2"1.8
Historical Pages
Long axis function Lateral amplitude (cm) S9 lateral (cmys) E9 lateral (cmys) Septal amplitude (cm) S9 septal (cmys) E9 lateral (cmys) Twist function Basal rotation (8) Apical rotation (8) Twist (8)
Pre AVR (ns28)
Nomenclature
Table 3. Left ventricular long axis and twist function in controls and in patients before and after AVR
Best Evidence Topic
In our AS patients with normal EF, we confirmed previous findings, having demonstrated increased septal thickness, reduced longitudinal function w13x as well as indirect signs of modestly increased LV filling pressures as shown by EyE9 w14x. In addition, we have confirmed that apical rotation and twist function were both exaggerated w6x. More interestingly was the relationship between different components of LV function. The normal LV twist is closely related to its
State-of-the-art
After AVR, LV dimensions and EF did not change but septal and posterior wall thickness regressed (P-0.001 for both) and LVFS increased (P-0.01). E9 increased (P-0.001) and EyE9 normalized (P-0.01) (Table 2). LV lateral and septal systolic long axis amplitude significantly increased (P-0.001 and P-0.05, respectively) as did their systolic velocities (P-0.001 for both). LV systolic apical rotation (P-0.001) and cavity twist (P-0.001) normalized after AVR (Table 3 and Fig. 1).
Negative Results
In normals, LV twist correlated strongly with LVFS (rs0.81, P-0.001). This relationship was significantly less in patients before AVR (rs0.52, P-0.01) and was completely lost after AVR (rs0.34, Psns) as shown in Fig. 2. In normals, LV twist (rs0.19, Psns) was not related to EF but was modestly related in patients preoperatively (rs 0.53, P-0.01) and less so after AVR (rs0.40, P-0.05).
Proposal for Bailout Procedure
reduced (P-0.01), EDT was prolonged (P-0.01), E9 was reduced resulting in raised EyE9 (P-0.001) and LV filling timeyRR was shortened (P-0.01) compared to controls (Table 2). Lateral and septal LV systolic long axis amplitude of motion were reduced (P-0.05 for both) as were their systolic velocities (P-0.01 and P-0.05, respectively) compared to controls. Peak apical systolic rotation (P-0.001) and cavity twist (P-0.001) were increased but basal systolic rotation was not different from controls (Psns) (Table 3).
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Fig. 1. Example of LV rotation and twist in control, preAVR and postAVR. Purple line showing peak of apical rotation and green showing peak basal rotation. AVR, aortic valve replacement.
ARTICLE IN PRESS P. Lindqvist et al. / Interactive CardioVascular and Thoracic Surgery 12 (2011) 701–706
705 Editorial New Ideas Work in Progress Report Protocol
removal of the high LV afterload by AS. While normally twist correlated strongly with basal systolic function (LVFS), this relationship fell in patients and was lost after AVR. The loss of such relationship after AVR suggests a surgery related additional factor which has interfered and disturbed the preoperative synchronous function. It is known that septal motion, which contributes to the twist function, becomes reversed after AVR w15x, and hence, redirecting systolic myocardial power to the right side and consequently affecting the twist function. The increased FS after AVR might be related to the augmented posterior wall motion as an attempt to compensate for the disturbed septal motion and to maintain global systolic function after AVR. 4.3. Clinical implications
Nomenclature Historical Pages Brief Case Report Communication
w1x Vahanian A, Baumgartner H, Bax J, Butchart E, Dion R, Filippatos G, Flachskampf F, Hall R, Iung B, Kasprzak J, Nataf P, Tornos P, Torracca L, Wenink A. Guidelines on the management of valvular heart disease: the Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology. Eur Heart J 2007;28:230–268. w2x Dineen E, Brent BN. Aortic valve stenosis: comparison of patients with to those without chronic congestive heart failure. Am J Cardiol 1986; 57:419–422. w3x Lindqvist P, Bajraktari G, Molle R, Palmerini E, Holmgren A, Mondillo S, Henein MY. Valve replacement for aortic stenosis normalizes subendocardial function in patients with normal ejection fraction. Eur J Echocardiogr 2010;11:608–613. w4x Shaw SM, Fox DJ, Williams SG. The development of left ventricular torsion and its clinical relevance. Int J Cardiol 2008;130:319–325.
Best Evidence Topic
References
State-of-the-art
In patients with severe AS and normal EF, LV twist is exaggerated suggesting potential compensation for the reduced long axis function. These disturbances normalize within six months of AVR but lose their relationship with basal LV function, and instead correlate with global systolic function. Finally, with the growing evidence on LV dysfunction in asymptomatic AS patients, similar findings may assist in identifying those needing surgery before LV damage becomes irreversible.
Follow-up Paper
5. Conclusion
Negative Results
To interpret our results, a clear appreciation of LV normal anatomy, in particular myocardial fibre architecture is essential, with the basal circumferential, longitudinal and oblique fibres controlling basal, long axis and rotation function, respectively. In our patients with AS and normal EF, the nature of long axis and cavity twist abnormalities were similar to what has previously been described, with the long axis function reduced and apical rotation and cavity twist function exaggerated. The apical rotation is commonly noticed by cardiac surgeons as soon as the chest is opened, and tends to reduce by the end of procedure. We have noticed similar findings in our patients in whom the apical rotation and cavity twist normalized after AVR as did long axis amplitudes and velocities, while EF remained unchanged. Such behaviour suggests a potential interaction between long axis function and twist function although we could not demonstrate such relationship statistically in our relatively small group of patients. Also, the relationship between twist and EF before AVR suggested that the exaggerated twist was the compensation for the decreased long axis function in order to maintain a normal global cavity function. When the long axis dysfunction improved after AVR, this relationship became less. On the other hand, there was a dynamic relationship between the three different LV functional components according to individual events. These changes might be related to the
The main limitation of this study is the small number of patients. At present we do not have long-term follow-up data on these patients which should determine the relevance of our findings. The clinical consequences of such postoperative changes on patients’ exercise capacity remain to be determined.
Proposal for Bailout Procedure
4.2. Mechanisms
4.4. Limitations
ESCVS Article
basal FS but was significantly less so in the patients preoperatively, and was completely lost after AVR. In contrast, global LV function, i.e. EF, did not correlate with cavity twist in normals but became correlated in patients before and to a less extent after AVR. Six months after AVR and with regression of LV hypertrophy, long axis function improved and twist function normalized. However, the relationship between LV twist and basal region shown by FS was lost.
Institutional Report
Fig. 2. Scatter plots with regression between LV fractional shortening (LVFS) and LV twist in controls and in patients before and after AVR. AVR, aortic valve replacement; ns, not significant.
Currently, available guidelines recommend AVR for AS only in symptomatic patients. The scale of symptoms in these patients is broad and also difficult to interpret. Our findings show the reversibility of functional abnormalities of the LV after AVR, thus highlighting the importance of early intervention in severe AS before irreversible myocardial damage develops. Actually, the visually exaggerated apical rotation seen after sternal opening might provide reliable information on the overall ventricular function and potential postoperative prognosis.
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w5x Nagel E, Stuber M, Burkhard B, Fischer SE, Scheidegger MB, Boesiger P, Hess OM. Cardiac rotation and relaxation in patients with aortic valve stenosis. Eur Heart J 2000;21:582–589. w6x Popescu BA, Calin A, Beladan CC, Muraru D, Rosca M, Deleanu D, Lancellotti P, Antonini-Canterin F, Nicolosi GL, Ginghina C. Left ventricular torsional dynamics in aortic stenosis: relationship between left ventricular untwisting and filling pressures. A two-dimensional speckle tracking study. Eur J Echocardiogr 2010;11:406–413. w7x Schiller NB. Two-dimensional echocardiographic determination of left ventricular volume, systolic function, and mass. Summary and discussion of the 1989 recommendations of the American Society of Echocardiography. Circulation 1991;84:I280–I287. w8x Quinones MA, Otto CM, Stoddard M, Waggoner A, Zoghbi WA. Recommendations for quantification of Doppler echocardiography: a report from the Doppler Quantification Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography. J Am Soc Echocardiogr 2002;15:167–184. w9x van Dalen BM, Vletter WB, Soliman OI, ten Cate FJ, Geleijnse ML. Importance of transducer position in the assessment of apical rotation by speckle tracking echocardiography. J Am Soc Echocardiogr 2008; 21:895–898.
w10x Notomi Y, Lysyansky P, Setser RM, Shiota T, Popovic ZB, Martin-Miklovic MG, Weaver JA, Oryszak SJ, Greenberg NL, White RD, Thomas JD. Measurement of ventricular torsion by two-dimensional ultrasound speckle tracking imaging. J Am Coll Cardiol 2005;45:2034–2041. w11x Jones CJ, Raposo L, Gibson DG. Functional importance of the long axis dynamics of the human left ventricle. Br Heart J 1990;63:215–220. w12x Gustafsson U, Lindqvist P, Morner S, Waldenstrom A. Assessment of regional rotation patterns improves the understanding of the systolic and diastolic left ventricular function: an echocardiographic speckletracking study in healthy individuals. Eur J Echocardiogr 2009;10:56– 61. w13x Cramariuc D, Gerdts E, Davidsen ES, Segadal L, Matre K. Myocardial deformation in aortic valve stenosis: relation to left ventricular geometry. Heart 2010;96:106–112. w14x Gjertsson P, Caidahl K, Farasati M, Oden A, Bech-Hanssen O. Preoperative moderate to severe diastolic dysfunction: a novel Doppler echocardiographic long-term prognostic factor in patients with severe aortic stenosis. J Thorac Cardiovasc Surg 2005;129:890–896. w15x Reynolds HR, Tunick PA, Grossi EA, Dilmanian H, Colvin SB, Kronzon I. Paradoxical septal motion after cardiac surgery: a review of 3292 cases. Clin Cardiol 2007;30:621–623.
