- Email: [email protected]
Relationship between restrictive Doppler mitral inflow pattern and myocardial viability after a first acute myocardial infarction
The Egyptian Heart Journal (2012) 64, 227–231
Egyptian Society of Cardiology
The Egyptian Heart Journal www.elsevier.com/locate/ehj www.sciencedirect.com
ORIGINAL ARTICLE
Relationship between restrictive Doppler mitral inflow pattern and myocardial viability after a first acute myocardial infarction Mohammed A. Oraby *, Mahmoud F. Ibrahim, Gamila M. Nasr, Ahmed A. El Hawary Department of Cardiovascular Medicine, Suez Canal University, Egypt Received 2 March 2012; accepted 23 June 2012 Available online 2 August 2012
KEYWORDS Dobutamine stress echocardiography; Restrictive Doppler mitral inflow; Acute myocardial infarction
Abstract Objective: This study was designed to evaluate the relation between restrictive Doppler mitral inflow pattern and echocardiographic indices of myocardial viability in patients with first acute myocardial infarction undergoing dobutamine stress echocardiography to determine the extent of infract zone viability. Methods: Fifty-six consecutive patients were studied 7 days after first ST-elevation acute myocardial infarction with high dose dobutamine stress echocardiography. A score model based on 16 segments and four grades was used to assess the left ventricular function. Viability was defined as an improvement in wall motion by at least one grade in two or more dysfunctional segments during any stage of the dobutamine infusion compared with the baseline. Pulsed-wave Doppler mitral inflow velocity was obtained at baseline (prior to dobutamine infusion) and restrictive pattern defined as E/A ratio P 2 and E-wave deceleration time 6 140 ms. Results: Restrictive mitral inflow pattern was detected in 25 (45%) patients. Seventeen (68%) patients in restrictive group received thrombolytic therapy while 26 (84%) in the non-restrictive group received this therapy (P = 0.001). Viability in the infracted territory was detected in 17 (54%) out of 31 patients in non-restrictive group, while only 3 (12%) out of 25 patients in restrictive group showed evidence of contractile reserve (P = 0.0001). Conclusions: This study showed a strong association between restrictive Doppler mitral inflow pattern and lack of myocardial contractile reserve during dobutamine stress echocardiography in patients with a first acute myocardial infraction. ª 2012 Egyptian Society of Cardiology. Production and hosting by Elsevier B.V. All rights reserved.
* Corresponding author. Address: Cardiology Department, Suez Canal University Hospital, Ismailia, Egypt. Tel.: +20 0106178663. E-mail address: [email protected] (M.A. Oraby). Peer review under responsibility of Egyptian Society of Cardiology.
.
Production and hosting by Elsevier
1. Background Marked changes in the diastolic properties of the left ventricle (LV) can occur in the presence of ischemic heart diseases. Acute myocardial ischemia slows ventricular relaxation and increases myocardial wall stiffness, while acute myocardial
1110-2608 ª 2012 Egyptian Society of Cardiology. Production and hosting by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.ehj.2012.06.002
228 infarction (AMI) causes more complex changes in ventricular pressure–volume relationship, depending on the size of the infraction and the time following infarction at which the measurements are made.1 The mitral Doppler inflow pattern accurately predicts LV filling pressures, allows identification of patients at high risk for progressive LV dilatation and can provide independent prognostic information over that of the assessment of LV systolic function. 2 Moreover, in patients with ischemic cardiomyopathy, the mitral inflow pattern has been found to be a potential predictor of echocardiographic and scintigraphic indices of myocardial viability and functional recovery after revascularization.3 Dobutamine stress echocardiography (DSE) has been used to determine the extent of infract zone viability, because the degree of contractile reserve elicited during dobutamine infusion provides an excellent assessment of myocardial necrosis coexisting with post-ischemic myocardial dysfunction.4,5 We postulated that in patients with AMI, the mitral Doppler inflow pattern is critically dependent on the amount of viable myocardium, and we sought to evaluate the relation between the restrictive mitral inflow pattern and the echocardiographic indices of myocardial viability during DSE.
M.A. Oraby et al. Patients were assigned to one of two groups based on Doppler mitral inflow pattern: a restrictive group with E/A ratio P 2 or E/A between 1–2 and DTE 6 140 ms (Fig. 1), and non-restrictive group with E/A ratio 6 2 and DTE P 140 ms.8,9 2.3. Dobutamine stress testing
2. Methods
Patients underwent DSE while taking all prescribed medications on average 7 days after onset of symptoms (between 5– 9 days) and before discharge. Dobutamine was administered intravenously by an infusion pump at the initial dosages of 2.5, 5 and 10 lg/kg per minute for 3 min each, followed by increments of 10 lg/kg per minute every 3 min, up to a maximal dose of 40 lg/kg per minute. The infusion was stopped in the presence of one of the following end points: achieving the target heart rate (85% of maximum predicted heart rate), angina, 2 mm or more ST-segment depression compared with baseline, new or worsening wall motion abnormalities, significant arrhythmias, severe hypertension (blood pressure > 230/ 120 mm Hg), or hypotension (decrease in systolic blood pressure > 30 mm Hg below the baseline measurement).10 Echocardiographic monitoring was performed continuously and digital acquisition of images was obtained at rest, at low dobutamine dose (10 lg/kg per minute); at peak dose, and during recovery. Blood pressure was manually measured at each stage by arm-cuff sphygmomanometer.
2.1. Patients
2.4. Echocardiographic analysis
We studied patients admitted with a first acute ST-segment elevation myocardial infarction to the Coronary Care Unit in Suez Canal University Hospital. The diagnosis of myocardial infarction was made by the acute typical ST-T wave changes and typical increase and decrease in serum creatine kinase (CK) and the MB isoenzyme of creatine kinase (CK-MB) enzyme levels in the clinical setting of sustained precordial chest pain.6 We excluded patients with previous myocardial infraction, atrial fibrillation, severe valvular heart diseases, intraventricular conduction defects, congestive heart failure, and technically difficult Doppler echocardiographic studies for quantitative analysis.
Improvement of contractile function in a segment during dobutamine infusion was defined when systolic myocardial thickening became apparent in an akinetic segment (from score 3 to 2 or 1) or when systolic thickening and wall motion comparable with those observed in the normal segments was observed in a previously hypokinetic segment (from 2 to 1). A patient was considered to have contractile reserve on dobutamine echocardiography if wall thickening improved in 2 or more contiguous segments. The development of new or worsening regional dyssynergy during dobutamine stress was considered to indicate ischemia.10,11 Four different echocardiographic responses were identified (1) Sustained improvement throughout the study, indicating contractile reserve with no ischemia (stunning), (2) Initial improvement followed by subsequent worsening at a higher dose, considered to represent a biphasic response (viable and ischemic), (3) Ischemia of the adjacent area, defined by the development of new dyssynergy in 2 or more segments adjacent to the infarcted zone, with no change in the affected segments (non-viable with ischemia at a distance), (4) No change in basal dyssynergy throughout dobutamine infusion (nonviable).10,11
2.2. Two dimensional and Doppler echocardiography Two dimensional and Doppler echocardiography were performed on average 7 days after onset of symptoms (ranged from 5 to 9 days) and prior to DSE. Images were obtained in the standard parasternal and apical views with the patient in left lateral position. Regional function assessment was performed according to the 16-segment model of the American Society of Echocardiography and graded from 1 to 4 (1 = normal, 2 = hypokinesia, 3 = akinesia, and 4 = dyskinesia). Wall motion score index (WMSI) was calculated by summing the scores for each segment and divided by the number of segments analyzed.7 Ejection fraction (EF) was calculated by Simpson method from the apical 2- and 4-chamber views. Pulsed-wave Doppler mitral inflow velocity was obtained by placing the Doppler sample volume at the tips of mitral valve leaflets in the apical 4-chamber view to measure the following: Peak early filling velocity (E), peak velocity at atrial contraction (A), E/A ratio, deceleration time of the E velocity (DTE).
2.5. Statistical analysis All continuous data are expressed as mean ± SD. Unpaired tor X2-tests were used to compare the clinical and echocardiographic data between the two groups of patients as divided by restrictive or non-restrictive filling patterns. Univariate and multivariate logistic regression analyses were performed to identify variables’ correlates with lack of myocardial viability detected by DSE after AMI. A value of P < 0.05 was considered to be statistically significant.
Relationship between restrictive Doppler mitral inflow pattern and myocardial viability
229
B
A E A
Figure 1 Two different patterns of restrictive mitral inflow Doppler signal. (A) Increased E/A ratio > 2, (B) short E-wave deceleration time < 140 ms.
3. Results This study included 56 patients; 40 of them were males (71%) with a mean age 57 ± 11 years. According to the Doppler pattern of mitral inflow, patients were divided into 2 groups: a restrictive group included 25 (45%) patients, and a non-restrictive group included 31 (55%) patients. Baseline clinical characteristics of both groups are shown in Table 1. Seventeen (68%) patients in restrictive group received thrombolytic therapy while 26 (84%) patients in the nonrestrictive group received this therapy (P = 0.001). Peak creatine kinase and creatine kinase MB were significantly higher among the restrictive group compared with the non-restrictive group (P = 0.006 and 0.001 respectively). 3.1. Baseline echocardiography
Table 1 Baseline clinical characteristics of patients in restrictive and non-restrictive groups.
*
Non-significant.
Variable
Pattern
Baseline EF % EF % with DSE Resting WMSI WMSi with DSE
p-Value
Restrictive
Non-restrictive
41 ± 7 44 ± 8 1.8 ± 0.2 1.7 ± 0.2
47 ± 4 55 ± 7 1.4 ± 0.4 1.2 ± 0.4
0.02 0.01 0.001 0.001
restrictive group compared to the non-restrictive group (P = 0.03). 3.2. DSE
Mean WMSI was significantly higher among the restrictive group (1.8 ± 0.2) compared with the non-restrictive group (1.4 ± 0.4) (P = 0.001). On the other hand the mean EF was significantly lower among the restrictive (41 ± 7) compared to the non-restrictive group (47 ± 4) (P = 0.02) (Table 2). Anterior MI was more commonly encountered among the
Age (mean ± SD) Sex Male Female Smoking DM Hypertension Dyslipidemia Obesity Family history of CAD Thrombolysis Peak CK-MB
Table 2 Indices of LV systolic functions in the restrictive and non-restrictive groups, at baseline and at peak dobutamine dose.
Restrictive
Non-restrictive
p-Value
57.9 ± 8.6
54 ± 9.5
NS*
16 9 11 9 13 19 12 3 17 (68%) 921 ± 307
24 7 14 13 17 26 15 3 26 (84%) 456 ± 216
NS NS NS NS NS NS NS 0.001 0.006
All included patients tolerated well the DSE protocol without any serious adverse events. Myocardial contractile reserve (defined by improvement in wall motion score by at least one grade in two or more dysfunctional segments during any stage of the dobutamine infusion compared with the baseline study) was detected in 17 (54%) out of 31 patients in non-restrictive and in 3 (12%) out of 25 patients in the restrictive group (Table 3). WMSI at peak dobutamine dose was significantly higher among the restrictive (1.7 + 0.2) compared with the nonrestrictive group (1.2 + 0.4) (P = 0.001). On the other hand, EF raised significantly among the non-restrictive (from 47 ± 4 to 55 ± 7) compared with the restrictive group (from 41 ± 7 to 44 ± 8) (P = 0.01).
Table 3 Relation between the Doppler mitral inflow pattern and viability detected during DSE. Viability
Viable Non-viable Total
Pattern
Total
Restrictive
Non-restrictive
No.
%
No.
%
No.
%
3 22 25
12 88 100
17 14 31
54 46 100
30 26 56
54 46 100
230 4. Discussion In this study we thought to explore the relation between the restrictive transmitral Doppler flow pattern (as a measure of severe LV diastolic dysfunction and elevated filling pressure) and the presence and extent of residual contractile reserve detected during DSE after first acute ST-elevation MI. We classified patients according to their baseline transmitral Doppler flow pattern as restrictive and non-restrictive groups according to previously mentioned criteria. We found that patients with restrictive mitral inflow pattern were more likely to have larger anterior myocardial infarctions with a higher peak creatine kinase levels and less likely to have received thrombolytic therapy in the acute phase compared with non-restrictive group. Similar observations were reported by other investigators.12–14 This is understandable as patients with these clinical scenarios are more likely to have sustained a larger mass of myonecrosis with minimal residual contractile reserve in the infarct zone. We also showed a significant correlation between the restrictive mitral flow pattern and a lower EF and higher WMSI at baseline, again emphasizing the correlation between this restrictive pattern and larger mass of dysfunctional myocardium.14,15 Out of 31 patients in non-restrictive group, residual myocardial viability was found in 17 (54%) patients, compared with 3 (12%) patients in the restrictive group (P = 0.0001). Similarly Sestili et al.,16 reported that in large infracts the reduced amount of viable myocardium and consequently the increase in LV chamber stiffness may explain the presence of a restrictive mitral inflow pattern. Rossi et al.,12 found that after AMI, left ventricular end diastolic pressure shows wide variability and is inversely correlated with the extent of residual myocardial viability. Recently, increasing attention has been devoted to diastolic function after AMI, and there is growing evidence indicating a strong association between diastolic dysfunction and adverse outcome, as increasing LV stiffness adversely affects the remodeling process and survival after AMI. Two studies reported that a baseline restrictive filling pattern that persists till discharge after AMI identifies more compromised patients at higher risk for six month remodeling and four-year mortality.17,18 We believe that the association between a restrictive filling and viability indices help elucidate the mechanism linking the mitral inflow pattern to remodeling and survival after AMI. There is currently strong evidence that the presence and extent of myocardial viability have a significant impact on the clinical outcome of patients after AMI. Recently color M-mode and tissue Doppler have provided useful insights into the study of diastolic function. These new Doppler applications may be combined with standard pulsed-wave Doppler indices to provide an accurate estimate of LV filling pressure and appear to be relatively insensitive to the effects of preload compensation,19 furthermore they make available prognostic information incremental to standard parameters and help to identify candidates for more aggressive therapeutic approaches. 5. Conclusion This study shows a strong association between restrictive mitral Doppler inflow pattern and lack of myocardial viability
M.A. Oraby et al. in the infarct zone during DSE in patients with a first acute myocardial infraction. References 1. Diamond C, Forrester JS. Effect of coronary artery disease and acute myocardial infarction on left ventricular compliance in man. Circulation 1972;45:11. 2. Nijland F, Kamp O, Karreman AJP, van Eenige MJ, Visser CA. Prognostic implications of restrictive left ventricular filling in acute myocardial infarction a serial Doppler echocardiographic study. J Am Coll Cardiol 1997;30:1618–24. 3. Yong Y, Nagueh SF, Sarah S, et al. Deceleration time in ischemic cardiomyopathy: relation to echocardiographic and seintigraphic indices of myocardial viability and functional recovery after revascularization. Circulation 2001;103:1232–7. 4. Smart SC, Wynsen J, Sagar K. Dobutamine–atropine stress echocardiography for reversible dysfunction during the first week after acute myocardial infarction: limitations and determinants of accuracy. J Am Coll Cardiol 1997;30:1669–78. 5. Carlos ME, Smart SC, Wynsen JC, Sagar KB. Dobutamine stress echocardiography for risk stratification after myocardial infarction. Circulation 1997;95:1402–10. 6. The Joint European Society of Cardiology/American College of Cardiology Committee. Myocardial infarction redefined – a consensus document of the Joint European Society of Cardiology/American College of Cardiology Committee for the Redefinition of Myocardial Infarction. Eur Heart J 2000;21:1502– 1513. 7. Schiller N, Provin M, Michael G, et al. Recommendation for quantitation of left ventricle by two- dimensional echocardiography. J Am Soc Echocardiogr 1999;2:358–76. 8. Ommen SR, Nishimura RA. A clinical approach to the assessment of left ventricular diastolic function by Doppler echocardiography. BMJ 2003;89:9–18. 9. Cohen GI, Pietrolungo JF, Thomas JD, et al. A practical guide to assessment of ventricular diastolic function using Doppler echocardiography. J Am Coll Cardiol 1996;27(7):1753–60. 10. Committee on Physician Training and Education of the American Society of Echocardiography. Recommendations for performance and interpretation of stress echocardiography. J Am Soc Echocardiogr 1998;11:97–104. 11. Smart SC, Knickelbine T, Stoiber TR, et al. Safety and accuracy of dobutamine-atropine stress echocardiography for the detection of residual stenosis of the infarct-related artery and multivessel disease during the first week after acute myocardial infarction. Circulation 1997;1995(6):1394–401. 12. Rossi A, Cicoira, Anselmi M, et al. Myocardial viability independently influences left ventricular diastolic function in the early phase after acute myocardial infarction. Circulation 2002;15:1490–5. 13. Cerisano G, Bolognese L, Buonamici P, Valenti R, Carrabba N, Dovellini EV, et al. Prognostic implications of restrictive left ventricular filling in reperfused anterior acute myocardial infarction. J Am Coll Cardiol 2001;37:793–9. 14. Poulsen SH, Jensen SE, Egstrup K. Longitudinal changes and prognostic implications of left ventricular diastolic function in first acute myocardial infarction. Am Heart J 1999;137:910–8. 15. Moller JE, Sondergaard E, Poulsen SH, Egstrup K. Pseudonormal and restrictive filling patterns predict left ventricular dilation and cardiac death after a first myocardial infarction: a serial color Mmode Doppler echocardiographic study. J Am Coll Cardiol 2000;36:1841–6. 16. Sestili Augusto, Coletta Claudio, Manno Valerio, et al. Restrictive mitral inflow pattern is a strong independent predictor of lack of viable myocardium after a first acute myocardial infarction. Eur J Echocardiogr 2007;8:332–40.
Relationship between restrictive Doppler mitral inflow pattern and myocardial viability 17. Coletta C, Sestili A, Seccareccia F, Rambaldi R, Ricci R, Galati A, et al. Influence of contractile reserve and inducible ischemia on left ventricular remodelling after acute myocardial infarction. Heart 2003;89:1138–43. 18. Cerisano G, Bolognese L, Carrabba N, Buonamici P, Santoro D, Anfoniucci D, et al. Doppler-derived mitral deceleration time: an early strong predictor of left ventricular remodelling after
231
reperfused anterior acute myocardial infarction. Circulation 1999;99:230–6. 19. Moller j, Sondergaard E, Seward J, et al. Ratio of left ventricular peak E- wave velocity to flow propagation velocity assessed by color M-mode Doppler echocardiography in first myocardial infarction: prognostic and clinical implications. J Am Coll Cardiol 2000;35:363–70.
Egyptian Society of Cardiology
The Egyptian Heart Journal www.elsevier.com/locate/ehj www.sciencedirect.com
ORIGINAL ARTICLE
Relationship between restrictive Doppler mitral inflow pattern and myocardial viability after a first acute myocardial infarction Mohammed A. Oraby *, Mahmoud F. Ibrahim, Gamila M. Nasr, Ahmed A. El Hawary Department of Cardiovascular Medicine, Suez Canal University, Egypt Received 2 March 2012; accepted 23 June 2012 Available online 2 August 2012
KEYWORDS Dobutamine stress echocardiography; Restrictive Doppler mitral inflow; Acute myocardial infarction
Abstract Objective: This study was designed to evaluate the relation between restrictive Doppler mitral inflow pattern and echocardiographic indices of myocardial viability in patients with first acute myocardial infarction undergoing dobutamine stress echocardiography to determine the extent of infract zone viability. Methods: Fifty-six consecutive patients were studied 7 days after first ST-elevation acute myocardial infarction with high dose dobutamine stress echocardiography. A score model based on 16 segments and four grades was used to assess the left ventricular function. Viability was defined as an improvement in wall motion by at least one grade in two or more dysfunctional segments during any stage of the dobutamine infusion compared with the baseline. Pulsed-wave Doppler mitral inflow velocity was obtained at baseline (prior to dobutamine infusion) and restrictive pattern defined as E/A ratio P 2 and E-wave deceleration time 6 140 ms. Results: Restrictive mitral inflow pattern was detected in 25 (45%) patients. Seventeen (68%) patients in restrictive group received thrombolytic therapy while 26 (84%) in the non-restrictive group received this therapy (P = 0.001). Viability in the infracted territory was detected in 17 (54%) out of 31 patients in non-restrictive group, while only 3 (12%) out of 25 patients in restrictive group showed evidence of contractile reserve (P = 0.0001). Conclusions: This study showed a strong association between restrictive Doppler mitral inflow pattern and lack of myocardial contractile reserve during dobutamine stress echocardiography in patients with a first acute myocardial infraction. ª 2012 Egyptian Society of Cardiology. Production and hosting by Elsevier B.V. All rights reserved.
* Corresponding author. Address: Cardiology Department, Suez Canal University Hospital, Ismailia, Egypt. Tel.: +20 0106178663. E-mail address: [email protected] (M.A. Oraby). Peer review under responsibility of Egyptian Society of Cardiology.
.
Production and hosting by Elsevier
1. Background Marked changes in the diastolic properties of the left ventricle (LV) can occur in the presence of ischemic heart diseases. Acute myocardial ischemia slows ventricular relaxation and increases myocardial wall stiffness, while acute myocardial
1110-2608 ª 2012 Egyptian Society of Cardiology. Production and hosting by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.ehj.2012.06.002
228 infarction (AMI) causes more complex changes in ventricular pressure–volume relationship, depending on the size of the infraction and the time following infarction at which the measurements are made.1 The mitral Doppler inflow pattern accurately predicts LV filling pressures, allows identification of patients at high risk for progressive LV dilatation and can provide independent prognostic information over that of the assessment of LV systolic function. 2 Moreover, in patients with ischemic cardiomyopathy, the mitral inflow pattern has been found to be a potential predictor of echocardiographic and scintigraphic indices of myocardial viability and functional recovery after revascularization.3 Dobutamine stress echocardiography (DSE) has been used to determine the extent of infract zone viability, because the degree of contractile reserve elicited during dobutamine infusion provides an excellent assessment of myocardial necrosis coexisting with post-ischemic myocardial dysfunction.4,5 We postulated that in patients with AMI, the mitral Doppler inflow pattern is critically dependent on the amount of viable myocardium, and we sought to evaluate the relation between the restrictive mitral inflow pattern and the echocardiographic indices of myocardial viability during DSE.
M.A. Oraby et al. Patients were assigned to one of two groups based on Doppler mitral inflow pattern: a restrictive group with E/A ratio P 2 or E/A between 1–2 and DTE 6 140 ms (Fig. 1), and non-restrictive group with E/A ratio 6 2 and DTE P 140 ms.8,9 2.3. Dobutamine stress testing
2. Methods
Patients underwent DSE while taking all prescribed medications on average 7 days after onset of symptoms (between 5– 9 days) and before discharge. Dobutamine was administered intravenously by an infusion pump at the initial dosages of 2.5, 5 and 10 lg/kg per minute for 3 min each, followed by increments of 10 lg/kg per minute every 3 min, up to a maximal dose of 40 lg/kg per minute. The infusion was stopped in the presence of one of the following end points: achieving the target heart rate (85% of maximum predicted heart rate), angina, 2 mm or more ST-segment depression compared with baseline, new or worsening wall motion abnormalities, significant arrhythmias, severe hypertension (blood pressure > 230/ 120 mm Hg), or hypotension (decrease in systolic blood pressure > 30 mm Hg below the baseline measurement).10 Echocardiographic monitoring was performed continuously and digital acquisition of images was obtained at rest, at low dobutamine dose (10 lg/kg per minute); at peak dose, and during recovery. Blood pressure was manually measured at each stage by arm-cuff sphygmomanometer.
2.1. Patients
2.4. Echocardiographic analysis
We studied patients admitted with a first acute ST-segment elevation myocardial infarction to the Coronary Care Unit in Suez Canal University Hospital. The diagnosis of myocardial infarction was made by the acute typical ST-T wave changes and typical increase and decrease in serum creatine kinase (CK) and the MB isoenzyme of creatine kinase (CK-MB) enzyme levels in the clinical setting of sustained precordial chest pain.6 We excluded patients with previous myocardial infraction, atrial fibrillation, severe valvular heart diseases, intraventricular conduction defects, congestive heart failure, and technically difficult Doppler echocardiographic studies for quantitative analysis.
Improvement of contractile function in a segment during dobutamine infusion was defined when systolic myocardial thickening became apparent in an akinetic segment (from score 3 to 2 or 1) or when systolic thickening and wall motion comparable with those observed in the normal segments was observed in a previously hypokinetic segment (from 2 to 1). A patient was considered to have contractile reserve on dobutamine echocardiography if wall thickening improved in 2 or more contiguous segments. The development of new or worsening regional dyssynergy during dobutamine stress was considered to indicate ischemia.10,11 Four different echocardiographic responses were identified (1) Sustained improvement throughout the study, indicating contractile reserve with no ischemia (stunning), (2) Initial improvement followed by subsequent worsening at a higher dose, considered to represent a biphasic response (viable and ischemic), (3) Ischemia of the adjacent area, defined by the development of new dyssynergy in 2 or more segments adjacent to the infarcted zone, with no change in the affected segments (non-viable with ischemia at a distance), (4) No change in basal dyssynergy throughout dobutamine infusion (nonviable).10,11
2.2. Two dimensional and Doppler echocardiography Two dimensional and Doppler echocardiography were performed on average 7 days after onset of symptoms (ranged from 5 to 9 days) and prior to DSE. Images were obtained in the standard parasternal and apical views with the patient in left lateral position. Regional function assessment was performed according to the 16-segment model of the American Society of Echocardiography and graded from 1 to 4 (1 = normal, 2 = hypokinesia, 3 = akinesia, and 4 = dyskinesia). Wall motion score index (WMSI) was calculated by summing the scores for each segment and divided by the number of segments analyzed.7 Ejection fraction (EF) was calculated by Simpson method from the apical 2- and 4-chamber views. Pulsed-wave Doppler mitral inflow velocity was obtained by placing the Doppler sample volume at the tips of mitral valve leaflets in the apical 4-chamber view to measure the following: Peak early filling velocity (E), peak velocity at atrial contraction (A), E/A ratio, deceleration time of the E velocity (DTE).
2.5. Statistical analysis All continuous data are expressed as mean ± SD. Unpaired tor X2-tests were used to compare the clinical and echocardiographic data between the two groups of patients as divided by restrictive or non-restrictive filling patterns. Univariate and multivariate logistic regression analyses were performed to identify variables’ correlates with lack of myocardial viability detected by DSE after AMI. A value of P < 0.05 was considered to be statistically significant.
Relationship between restrictive Doppler mitral inflow pattern and myocardial viability
229
B
A E A
Figure 1 Two different patterns of restrictive mitral inflow Doppler signal. (A) Increased E/A ratio > 2, (B) short E-wave deceleration time < 140 ms.
3. Results This study included 56 patients; 40 of them were males (71%) with a mean age 57 ± 11 years. According to the Doppler pattern of mitral inflow, patients were divided into 2 groups: a restrictive group included 25 (45%) patients, and a non-restrictive group included 31 (55%) patients. Baseline clinical characteristics of both groups are shown in Table 1. Seventeen (68%) patients in restrictive group received thrombolytic therapy while 26 (84%) patients in the nonrestrictive group received this therapy (P = 0.001). Peak creatine kinase and creatine kinase MB were significantly higher among the restrictive group compared with the non-restrictive group (P = 0.006 and 0.001 respectively). 3.1. Baseline echocardiography
Table 1 Baseline clinical characteristics of patients in restrictive and non-restrictive groups.
*
Non-significant.
Variable
Pattern
Baseline EF % EF % with DSE Resting WMSI WMSi with DSE
p-Value
Restrictive
Non-restrictive
41 ± 7 44 ± 8 1.8 ± 0.2 1.7 ± 0.2
47 ± 4 55 ± 7 1.4 ± 0.4 1.2 ± 0.4
0.02 0.01 0.001 0.001
restrictive group compared to the non-restrictive group (P = 0.03). 3.2. DSE
Mean WMSI was significantly higher among the restrictive group (1.8 ± 0.2) compared with the non-restrictive group (1.4 ± 0.4) (P = 0.001). On the other hand the mean EF was significantly lower among the restrictive (41 ± 7) compared to the non-restrictive group (47 ± 4) (P = 0.02) (Table 2). Anterior MI was more commonly encountered among the
Age (mean ± SD) Sex Male Female Smoking DM Hypertension Dyslipidemia Obesity Family history of CAD Thrombolysis Peak CK-MB
Table 2 Indices of LV systolic functions in the restrictive and non-restrictive groups, at baseline and at peak dobutamine dose.
Restrictive
Non-restrictive
p-Value
57.9 ± 8.6
54 ± 9.5
NS*
16 9 11 9 13 19 12 3 17 (68%) 921 ± 307
24 7 14 13 17 26 15 3 26 (84%) 456 ± 216
NS NS NS NS NS NS NS 0.001 0.006
All included patients tolerated well the DSE protocol without any serious adverse events. Myocardial contractile reserve (defined by improvement in wall motion score by at least one grade in two or more dysfunctional segments during any stage of the dobutamine infusion compared with the baseline study) was detected in 17 (54%) out of 31 patients in non-restrictive and in 3 (12%) out of 25 patients in the restrictive group (Table 3). WMSI at peak dobutamine dose was significantly higher among the restrictive (1.7 + 0.2) compared with the nonrestrictive group (1.2 + 0.4) (P = 0.001). On the other hand, EF raised significantly among the non-restrictive (from 47 ± 4 to 55 ± 7) compared with the restrictive group (from 41 ± 7 to 44 ± 8) (P = 0.01).
Table 3 Relation between the Doppler mitral inflow pattern and viability detected during DSE. Viability
Viable Non-viable Total
Pattern
Total
Restrictive
Non-restrictive
No.
%
No.
%
No.
%
3 22 25
12 88 100
17 14 31
54 46 100
30 26 56
54 46 100
230 4. Discussion In this study we thought to explore the relation between the restrictive transmitral Doppler flow pattern (as a measure of severe LV diastolic dysfunction and elevated filling pressure) and the presence and extent of residual contractile reserve detected during DSE after first acute ST-elevation MI. We classified patients according to their baseline transmitral Doppler flow pattern as restrictive and non-restrictive groups according to previously mentioned criteria. We found that patients with restrictive mitral inflow pattern were more likely to have larger anterior myocardial infarctions with a higher peak creatine kinase levels and less likely to have received thrombolytic therapy in the acute phase compared with non-restrictive group. Similar observations were reported by other investigators.12–14 This is understandable as patients with these clinical scenarios are more likely to have sustained a larger mass of myonecrosis with minimal residual contractile reserve in the infarct zone. We also showed a significant correlation between the restrictive mitral flow pattern and a lower EF and higher WMSI at baseline, again emphasizing the correlation between this restrictive pattern and larger mass of dysfunctional myocardium.14,15 Out of 31 patients in non-restrictive group, residual myocardial viability was found in 17 (54%) patients, compared with 3 (12%) patients in the restrictive group (P = 0.0001). Similarly Sestili et al.,16 reported that in large infracts the reduced amount of viable myocardium and consequently the increase in LV chamber stiffness may explain the presence of a restrictive mitral inflow pattern. Rossi et al.,12 found that after AMI, left ventricular end diastolic pressure shows wide variability and is inversely correlated with the extent of residual myocardial viability. Recently, increasing attention has been devoted to diastolic function after AMI, and there is growing evidence indicating a strong association between diastolic dysfunction and adverse outcome, as increasing LV stiffness adversely affects the remodeling process and survival after AMI. Two studies reported that a baseline restrictive filling pattern that persists till discharge after AMI identifies more compromised patients at higher risk for six month remodeling and four-year mortality.17,18 We believe that the association between a restrictive filling and viability indices help elucidate the mechanism linking the mitral inflow pattern to remodeling and survival after AMI. There is currently strong evidence that the presence and extent of myocardial viability have a significant impact on the clinical outcome of patients after AMI. Recently color M-mode and tissue Doppler have provided useful insights into the study of diastolic function. These new Doppler applications may be combined with standard pulsed-wave Doppler indices to provide an accurate estimate of LV filling pressure and appear to be relatively insensitive to the effects of preload compensation,19 furthermore they make available prognostic information incremental to standard parameters and help to identify candidates for more aggressive therapeutic approaches. 5. Conclusion This study shows a strong association between restrictive mitral Doppler inflow pattern and lack of myocardial viability
M.A. Oraby et al. in the infarct zone during DSE in patients with a first acute myocardial infraction. References 1. Diamond C, Forrester JS. Effect of coronary artery disease and acute myocardial infarction on left ventricular compliance in man. Circulation 1972;45:11. 2. Nijland F, Kamp O, Karreman AJP, van Eenige MJ, Visser CA. Prognostic implications of restrictive left ventricular filling in acute myocardial infarction a serial Doppler echocardiographic study. J Am Coll Cardiol 1997;30:1618–24. 3. Yong Y, Nagueh SF, Sarah S, et al. Deceleration time in ischemic cardiomyopathy: relation to echocardiographic and seintigraphic indices of myocardial viability and functional recovery after revascularization. Circulation 2001;103:1232–7. 4. Smart SC, Wynsen J, Sagar K. Dobutamine–atropine stress echocardiography for reversible dysfunction during the first week after acute myocardial infarction: limitations and determinants of accuracy. J Am Coll Cardiol 1997;30:1669–78. 5. Carlos ME, Smart SC, Wynsen JC, Sagar KB. Dobutamine stress echocardiography for risk stratification after myocardial infarction. Circulation 1997;95:1402–10. 6. The Joint European Society of Cardiology/American College of Cardiology Committee. Myocardial infarction redefined – a consensus document of the Joint European Society of Cardiology/American College of Cardiology Committee for the Redefinition of Myocardial Infarction. Eur Heart J 2000;21:1502– 1513. 7. Schiller N, Provin M, Michael G, et al. Recommendation for quantitation of left ventricle by two- dimensional echocardiography. J Am Soc Echocardiogr 1999;2:358–76. 8. Ommen SR, Nishimura RA. A clinical approach to the assessment of left ventricular diastolic function by Doppler echocardiography. BMJ 2003;89:9–18. 9. Cohen GI, Pietrolungo JF, Thomas JD, et al. A practical guide to assessment of ventricular diastolic function using Doppler echocardiography. J Am Coll Cardiol 1996;27(7):1753–60. 10. Committee on Physician Training and Education of the American Society of Echocardiography. Recommendations for performance and interpretation of stress echocardiography. J Am Soc Echocardiogr 1998;11:97–104. 11. Smart SC, Knickelbine T, Stoiber TR, et al. Safety and accuracy of dobutamine-atropine stress echocardiography for the detection of residual stenosis of the infarct-related artery and multivessel disease during the first week after acute myocardial infarction. Circulation 1997;1995(6):1394–401. 12. Rossi A, Cicoira, Anselmi M, et al. Myocardial viability independently influences left ventricular diastolic function in the early phase after acute myocardial infarction. Circulation 2002;15:1490–5. 13. Cerisano G, Bolognese L, Buonamici P, Valenti R, Carrabba N, Dovellini EV, et al. Prognostic implications of restrictive left ventricular filling in reperfused anterior acute myocardial infarction. J Am Coll Cardiol 2001;37:793–9. 14. Poulsen SH, Jensen SE, Egstrup K. Longitudinal changes and prognostic implications of left ventricular diastolic function in first acute myocardial infarction. Am Heart J 1999;137:910–8. 15. Moller JE, Sondergaard E, Poulsen SH, Egstrup K. Pseudonormal and restrictive filling patterns predict left ventricular dilation and cardiac death after a first myocardial infarction: a serial color Mmode Doppler echocardiographic study. J Am Coll Cardiol 2000;36:1841–6. 16. Sestili Augusto, Coletta Claudio, Manno Valerio, et al. Restrictive mitral inflow pattern is a strong independent predictor of lack of viable myocardium after a first acute myocardial infarction. Eur J Echocardiogr 2007;8:332–40.
Relationship between restrictive Doppler mitral inflow pattern and myocardial viability 17. Coletta C, Sestili A, Seccareccia F, Rambaldi R, Ricci R, Galati A, et al. Influence of contractile reserve and inducible ischemia on left ventricular remodelling after acute myocardial infarction. Heart 2003;89:1138–43. 18. Cerisano G, Bolognese L, Carrabba N, Buonamici P, Santoro D, Anfoniucci D, et al. Doppler-derived mitral deceleration time: an early strong predictor of left ventricular remodelling after
231
reperfused anterior acute myocardial infarction. Circulation 1999;99:230–6. 19. Moller j, Sondergaard E, Seward J, et al. Ratio of left ventricular peak E- wave velocity to flow propagation velocity assessed by color M-mode Doppler echocardiography in first myocardial infarction: prognostic and clinical implications. J Am Coll Cardiol 2000;35:363–70.