© 2014, Wiley Periodicals, Inc. DOI: 10.1111/echo.12677
Echocardiography
ORIGINAL INVESTIGATION
Effect of Remote Ischemic Postconditioning on Left Ventricular Mechanics Alper Bugra Nacar, M.D.,* Selim Topcu, M.D.,† Mustafa Kurt, M.D.,* Ibrahim Halil Tanboga, M.D.,* Mehmet Fatih Karakasß, M.D.,* Eyup Buyukkaya, M.D.,* Enbiya Aksakal, M.D.,† Nihat Sen, M.D.,* Adnan Burak Akcay, M.D.,* and Emine Bilen, M.D.‡ *Mustafa Kemal University, School of Medicine, Hatay, Turkey; †School of Medicine, Ataturk University, Erzurum, Turkey; and ‡Ankara Ataturk Education and Research Hospital, Ankara, Turkey
Background: Remote ischemic postconditioning (RIPC) decreases infarct size and prevents left ventricular (LV) remodeling in patients with myocardial infarction. However, there is no study that evaluates the effect of RIPC on LV mechanics assessed by speckle tracking echocardiography. Therefore, we aimed to test the effects of RIPC on LV deformation parameters such as strain, strain rate, rotation, and twist in healthy subjects. Methods: The study group consisted of 22 healthy subjects. To test the effects of RIPC, 3 cycles of reperfusion followed by ischemia (each lasting 10 or 30 seconds) were applied immediately after 20 minutes of nondominant arm ischemia. Transthoracic echocardiography (TTE) was obtained at baseline and repeated 30 minutes after the completion of these cycles. In TTE images, apical 4-3-2 chamber longitudinal strain (LS)/strain rate, basal and apical circumferential strain/strain rate, and rotational parameters, such as basal rotation, apical rotation, and LV twist, were recorded. Results: Apical 43-2 chamber LS and apical circumferential strain/strain rate measurements were comparable before and after RIPC, whereas basal circumferential strain was significantly decreased after RIPC ( 23 3.4 vs. 18.9 6.9, P = 0.017). After RIPC, apical rotation was significantly increased (11.6 3.7 vs. 16.7 4.0, P < 0.001) and basal rotation was significantly decreased ( 6.1 2.1 vs. 4.7 2.4, P = 0.03).Consequently, net LV twist was significantly increased (17.4 4.5 vs. 21.7 4.7). Conclusions: We proposed that RIPC affects the rotational mechanics of the heart rather than longitudinal mechanics. These results might give new insights into understanding the favorable effects of the postconditioning. (Echocardiography 2014;00:1–6) Key words: ischemic postconditioning, echocardiography, left ventricular deformation Infarct size is a major determinant of survival in patients with acute myocardial infarction (AMI). To limit the infarct size, normalization of both epicardial flow and microvascular perfusion should be achieved through optimal reperfusion therapy.1 However, despite its beneficial impact, reperfusion also leads to detrimental effects such as myocardial stunning, ventricular arrhythmias, no-reflow phenomenon, and lethal reperfusion injury.2 The phenomenon of ischemic postconditioning (IPC) is a potent new strategy to further reduce infarct size related to reperfusion injury.2,3 IPC is defined as brief repeating re-occlusion cycles of infarct-related coronary artery following severe ischemia during early reperfusion.4 Previous studies suggest that intermittent reperfusion This study was presented in part at the European Society of Cardiology Congress, Munich, Germany, 2012. Address for correspondence and reprint requests: Mustafa € Kurt, M.D., Mustafa Kemal Universitesi Arastirma Hastanesi, Kardiyoloji A.B.D., Hatay, 31001, Turkey. Fax: +90 326 2325089; E-mail: [email protected]
is associated with less postreperfusion injuries than rapid reperfusion. Abrupt reperfusion causes sudden exposure to oxygen which leads to the formation of free radicals and cytosolic calcium overload.2 Additionally, ischemic myocardium can also be protected by a brief episode of ischemia-reperfusion during peripheral tissue ischemia.5 This remote IPC using transient upper or lower limb ischemia is a simple noninvasive stimulus and it has been demonstrated that both remote ischemic postconditioning (RIPC) and IPC have comparable efficacy in reducing the infarct size.6 Speckle tracking echocardiography (STE) is a new echocardiographic imaging modality that is capable of angle-independent measurement of myocardial wall motion.7 Longitudinal, circumferential, and radial strains are used to describe left ventricular (LV) deformation in 3 dimensions. In addition, myocardial shear in the circumferential-longitudinal plane results in twisting or torsional deformation of the left ventricle during ejection.8 It has been reported that LV twist may 1
Nacar, et al.
be used for noninvasive quantification of LV regional function in ischemic heart disease.9 However, to our knowledge, no study has assessed the LV mechanics in RIPC. Therefore, the aim of this study was to evaluate the effects of RIPC on LV deformation parameters such as strain, strain rate, rotation, and twist in healthy subjects. Materials and Methods: Patient Population: Consecutively selected 22 individuals of both sexes, older than 18 years of age, were studied. After a careful physical examination and assessment of medical history, patients were excluded if they had any type of cardiac arrhythmia, structurally heart disease, history of smoking, hypertension, diabetes mellitus, chronic renal and liver disease, a history of cerebral vascular disease, lack of 1 of the upper limbs, and arterial pathology. All participants provided written consent, and the study was approved by the local ethics committee. Ischemic Postconditioning: The nondominant arm was made ischemic by inflating the blood pressure cuff (a 13.5-cm wide nylon pneumatic cuff (“wide cuffs;” 85 cm length; Hokanson, Bellevue, WA, USA) to a pressure of 200 mmHg for 20 minutes. After index ischemia, the arm was allowed to undergo reperfusion for 10 seconds, after which the blood pressure cuff was inflated again to 200 mmHg and the arm was made ischemic for 10 seconds. This deflation/inflation cycle was repeated a total of 3 times. Echocardiography: All subjects underwent a detailed transthoracic echocardiographic examination in the left lateral position. Every examination was performed at rest, without using sedation. All data were transferred to a workstation for further offline analysis (EchoPAC PC; GE Vingmed Ultrasound AS, Horten, Norway). Transthoracic echocardiography (TTE) was obtained at baseline and repeated 30 minutes after the completion of these cycles. All patients underwent an echocardiographic examination using the GE Vivid 7 system (GE Vingmed Ultrasound AS) with a 3.5-MHz transducer. LV-EF was calculated using the Simpson’s formula from the measurement of end-diastolic and end-systolic volumes on apical four-chamber views. Peak early diastolic velocity (E) and peak late diastolic velocity (A) were measured. The early diastolic annular velocity (Em) was measured by means of tissue Doppler imaging at the septal and lateral border of the mitral annulus
2
and averaged. Quantification of cardiac chamber size, ventricular mass, and systolic and diastolic LV function was measured in accordance with the recommendations for chamber quantification by the American Society of Echocardiography’s Guidelines and Standard Committee and the Chamber Quantification Writing Group. Two-dimensional (2D) echocardiography images were obtained from LV apical four chamber (4C), LAX (long axis) and two-chamber (2C) view. All images were obtained during breath hold, and stored in cine loop format from 3 consecutive beats. The frame rate for images was between 50 and 90 frames/sec. All data were transferred to a workstation for further offline analysis. After defining the endocardial border manually, an epicardial tracing was automatically developed by the software system for each view. If the automatically obtained tracking segments were adequate for analysis, the software system was allowed to read the data, whereas analytically inadequate tracking segments were either corrected manually or excluded from the analysis. Strain measurements were reported as the peak longitudinal strain (LS) for 4C, LAX, and 2C views, and global strain (GS) was calculated by averaging the 3 apical views. The parasternal short-axis views at the base (tips of the mitral valve leaflets), the level of the papillary muscles, and the apex (with the minimum circular LV cavity at end-systole) were used for radial and circumferential strain and rotation analysis. The radial and circumferential strains and rotation were calculated as a strain average of 6 basal segments, 6 papillary segments, and 4 apical segments. The LV twist was calculated as an absolute apex-to-base difference in LV rotation. Measurement Variability: The intra-observer (M. K.) and inter-observer (A. B. N. and M. K.) variability for LV deformation parameters were assessed in all participants. For intra-observer assessment, the measurements were re-analyzed after 2 weeks. Intraclass correlation coefficients (ICC) for each measurement were used to quantify variability (An ICC 0.75 as excellent agreement). The degree of inter-observer and intra-observer agreement for LVtw, and LV strain measurements were perfect (All ICC values >0.75). Statistical Analysis: Descriptive statistics are presented as the mean standard deviation (SD) for continuous variables, median (interquartile range) for discontinuous variables, and frequencies and percentages for categorical variables. The clinical
LV Deformation in Ischemic Postconditioning
characteristics and laboratory data were analyzed with an independent t-test for continuous variables and chi-square tests or for categorical data. The variables were evaluated using visual (histograms, probability plots) and analytical methods (Kolmogorov–Simirnov/Shapiro–Wilk test) to determine whether they are normally distributed or not. For all statistical analyses, significance was assumed at P-value less than 0.05. Statistical analyses were performed using the SPSS software version 15 (SPSS Inc, Chicago, IL, USA). Results: A total of 22 consecutive healthy individuals (mean age was 28.9 4.2 years and female ratio was 36.4%) were included in the study. The echocardiographic characteristic of the study group before and after RIPC are presented in Table I. There were no significant difference between groups regarding E-wave, A-wave, systolic blood pressure, left ventricular ejection fraction (LVEF), heart rate, end-systolic volume (ESV) and end-diastolic volume (EDV) before and after RIPC. However, circumferential strain was significantly decreased, apical rotation was significantly increased and basal rotation was significantly decreased after RIPC. In the analysis, there was no significant difference between 4C-LS ( 20.5 2.3 vs. 19.9 1.6, respectively, P: 0.383), LAX-LS ( 19.9 2.1 vs. 19 2.2, respectively, P: 0.190), 2C-LS ( 21.2 2.6 vs. 20.2 2.2, respectively, P: 0.166) and GS ( 20.6 1.9 vs. 19.8 2, respectively, P: 0.201) values between before and after RIPC. Also there was no significant difference between 4C-LSr, LAX-LSr and 2C-LSr values between before and after RIPC
TABLE II Differences between Longitudinal Mechanics before and after RIPC Variables
Before RIPC
4C-LS, % LAX-LS, % 2C-LS, % 4C-Sr, sm 4C-Sr, em 4C-Sr, am LAX-Sr, sm LAX-Sr, em LAX-Sr, am 2C-Sr, sm 2C-Sr, em 2C-Sr, am GS, % GSr, sm GSr, em GSr, am
20.5 19.9 21.2 1.05 1.45 0.73 1.07 1.43 0.69 1.14 1.4 0.72 20.6 1.08 1.42 0.71
2.3 2.1 2.6 0.17 0.29 0.18 0.17 0.33 0.2 0.19 0.41 0.15 1.9 0.14 0.28 0.16
After RIPC 19.9 19 20.2 0.99 1.36 0.69 1.12 1.44 0.69 1.09 1.27 0.67 19.8 1.07 1.35 0.68
1.6 2.2 2.2 0.13 0.21 0.19 0.3 0.44 0.2 0.16 0.29 0.17 2 0.17 0.26 0.2
P-Value 0.383 0.190 0.166 0.162 0.267 0.439 0.654 0.511 0.998 0.434 0.216 0.369 0.201 0.762 0.427 0.598
4C = apical four-chamber view, LAX = apical long-axis view, 2C = apical two-chamber view, LS = longitudinal strain, Sr = strain rate, sm = systolic strain rate, em = early diastolic strain rate, am = late diastolic strain rate, GS = global strain, GSr = global strain rate; RIPC = remote ischemic postconditioning.
(Table II). While there were no significant differences in apical circumferential strain/strain rate measurements, basal circumferential strain was significantly decreased after RIPC ( 21.03 3.85 vs. 18.89 2.88, respectively, P: 0.043) (Table III) (Fig. 1). Besides, there were no significant differences in basal and apical radial strain measurements before and after RIPC.
TABLE III Differences between Circumferential and Rotational Mechanics before and after RIPC
TABLE I The Echocardiographic Characteristic of the Study Group before and after RIPC Variables
Before RIPC
SBP E, m/sec A, m/sec E/A Average Em, m/sec LVEF, % Heart rate, per min LVEDD-mm LVESD-mm LA-mm
117 0.82 0.67 1.25 0.13 66.5 73 47.4 28.8 28.7
12.5 0.25 0.14 0.35 0.03 3.3 9.1 2.6 2.3 2.9
After RIPC 115 0.79 0.64 1.26 0.12 66 72.1 47.6 29 28.9
10.0 0.16 0.10 0.28 0.04 2.9 9.2 2.6 2.2 3.1
P-Value 0.425 0.310 0.121 0.896 0.456 0.607 0.588 0.819 0.794 0.881
SBP = systolic blood pressure, LVEF = left ventricular ejection fraction, LVEDD = left ventricular end-diastolic diameter, LVESD = left ventricular end-systolic diameter, LA = left atrium; RIPC = remote ischemic postconditioning.
Variables
Before RIPC
Apical CS, % Apical CSr, sm Apical CSr, em Apical CSr, am Basal CS, % Basal CSr, sm Basal CSr, em Basal CSr, am Basal RS, % Apical RS, % Apical rotation Basal rotation Left ventricular twist
32.7 2.31 3.43 0.86 23 1.31 1.7 0.57 38.1 14.6 11.6 6.1 17.4
6.7 0.79 1.58 0.31 3.4 0.32 0.56 0.19 12.8 8.9 3.7 2.1 4.5
After RIPC 32.2 2.17 3.51 0.89 18.9 1.24 1.5 0.58 37.9 14.5 16.7 4.7 21.7
6.7 0.81 1.31 0.37 6.9 0.35 0.58 0.16 13.6 9.7 4.0 2.4 4.7
P-Value 0.784 0.575 0.922 0.787 0.017 0.489 0.247 0.912 0.866 0.916
Echocardiography
ORIGINAL INVESTIGATION
Effect of Remote Ischemic Postconditioning on Left Ventricular Mechanics Alper Bugra Nacar, M.D.,* Selim Topcu, M.D.,† Mustafa Kurt, M.D.,* Ibrahim Halil Tanboga, M.D.,* Mehmet Fatih Karakasß, M.D.,* Eyup Buyukkaya, M.D.,* Enbiya Aksakal, M.D.,† Nihat Sen, M.D.,* Adnan Burak Akcay, M.D.,* and Emine Bilen, M.D.‡ *Mustafa Kemal University, School of Medicine, Hatay, Turkey; †School of Medicine, Ataturk University, Erzurum, Turkey; and ‡Ankara Ataturk Education and Research Hospital, Ankara, Turkey
Background: Remote ischemic postconditioning (RIPC) decreases infarct size and prevents left ventricular (LV) remodeling in patients with myocardial infarction. However, there is no study that evaluates the effect of RIPC on LV mechanics assessed by speckle tracking echocardiography. Therefore, we aimed to test the effects of RIPC on LV deformation parameters such as strain, strain rate, rotation, and twist in healthy subjects. Methods: The study group consisted of 22 healthy subjects. To test the effects of RIPC, 3 cycles of reperfusion followed by ischemia (each lasting 10 or 30 seconds) were applied immediately after 20 minutes of nondominant arm ischemia. Transthoracic echocardiography (TTE) was obtained at baseline and repeated 30 minutes after the completion of these cycles. In TTE images, apical 4-3-2 chamber longitudinal strain (LS)/strain rate, basal and apical circumferential strain/strain rate, and rotational parameters, such as basal rotation, apical rotation, and LV twist, were recorded. Results: Apical 43-2 chamber LS and apical circumferential strain/strain rate measurements were comparable before and after RIPC, whereas basal circumferential strain was significantly decreased after RIPC ( 23 3.4 vs. 18.9 6.9, P = 0.017). After RIPC, apical rotation was significantly increased (11.6 3.7 vs. 16.7 4.0, P < 0.001) and basal rotation was significantly decreased ( 6.1 2.1 vs. 4.7 2.4, P = 0.03).Consequently, net LV twist was significantly increased (17.4 4.5 vs. 21.7 4.7). Conclusions: We proposed that RIPC affects the rotational mechanics of the heart rather than longitudinal mechanics. These results might give new insights into understanding the favorable effects of the postconditioning. (Echocardiography 2014;00:1–6) Key words: ischemic postconditioning, echocardiography, left ventricular deformation Infarct size is a major determinant of survival in patients with acute myocardial infarction (AMI). To limit the infarct size, normalization of both epicardial flow and microvascular perfusion should be achieved through optimal reperfusion therapy.1 However, despite its beneficial impact, reperfusion also leads to detrimental effects such as myocardial stunning, ventricular arrhythmias, no-reflow phenomenon, and lethal reperfusion injury.2 The phenomenon of ischemic postconditioning (IPC) is a potent new strategy to further reduce infarct size related to reperfusion injury.2,3 IPC is defined as brief repeating re-occlusion cycles of infarct-related coronary artery following severe ischemia during early reperfusion.4 Previous studies suggest that intermittent reperfusion This study was presented in part at the European Society of Cardiology Congress, Munich, Germany, 2012. Address for correspondence and reprint requests: Mustafa € Kurt, M.D., Mustafa Kemal Universitesi Arastirma Hastanesi, Kardiyoloji A.B.D., Hatay, 31001, Turkey. Fax: +90 326 2325089; E-mail: [email protected]
is associated with less postreperfusion injuries than rapid reperfusion. Abrupt reperfusion causes sudden exposure to oxygen which leads to the formation of free radicals and cytosolic calcium overload.2 Additionally, ischemic myocardium can also be protected by a brief episode of ischemia-reperfusion during peripheral tissue ischemia.5 This remote IPC using transient upper or lower limb ischemia is a simple noninvasive stimulus and it has been demonstrated that both remote ischemic postconditioning (RIPC) and IPC have comparable efficacy in reducing the infarct size.6 Speckle tracking echocardiography (STE) is a new echocardiographic imaging modality that is capable of angle-independent measurement of myocardial wall motion.7 Longitudinal, circumferential, and radial strains are used to describe left ventricular (LV) deformation in 3 dimensions. In addition, myocardial shear in the circumferential-longitudinal plane results in twisting or torsional deformation of the left ventricle during ejection.8 It has been reported that LV twist may 1
Nacar, et al.
be used for noninvasive quantification of LV regional function in ischemic heart disease.9 However, to our knowledge, no study has assessed the LV mechanics in RIPC. Therefore, the aim of this study was to evaluate the effects of RIPC on LV deformation parameters such as strain, strain rate, rotation, and twist in healthy subjects. Materials and Methods: Patient Population: Consecutively selected 22 individuals of both sexes, older than 18 years of age, were studied. After a careful physical examination and assessment of medical history, patients were excluded if they had any type of cardiac arrhythmia, structurally heart disease, history of smoking, hypertension, diabetes mellitus, chronic renal and liver disease, a history of cerebral vascular disease, lack of 1 of the upper limbs, and arterial pathology. All participants provided written consent, and the study was approved by the local ethics committee. Ischemic Postconditioning: The nondominant arm was made ischemic by inflating the blood pressure cuff (a 13.5-cm wide nylon pneumatic cuff (“wide cuffs;” 85 cm length; Hokanson, Bellevue, WA, USA) to a pressure of 200 mmHg for 20 minutes. After index ischemia, the arm was allowed to undergo reperfusion for 10 seconds, after which the blood pressure cuff was inflated again to 200 mmHg and the arm was made ischemic for 10 seconds. This deflation/inflation cycle was repeated a total of 3 times. Echocardiography: All subjects underwent a detailed transthoracic echocardiographic examination in the left lateral position. Every examination was performed at rest, without using sedation. All data were transferred to a workstation for further offline analysis (EchoPAC PC; GE Vingmed Ultrasound AS, Horten, Norway). Transthoracic echocardiography (TTE) was obtained at baseline and repeated 30 minutes after the completion of these cycles. All patients underwent an echocardiographic examination using the GE Vivid 7 system (GE Vingmed Ultrasound AS) with a 3.5-MHz transducer. LV-EF was calculated using the Simpson’s formula from the measurement of end-diastolic and end-systolic volumes on apical four-chamber views. Peak early diastolic velocity (E) and peak late diastolic velocity (A) were measured. The early diastolic annular velocity (Em) was measured by means of tissue Doppler imaging at the septal and lateral border of the mitral annulus
2
and averaged. Quantification of cardiac chamber size, ventricular mass, and systolic and diastolic LV function was measured in accordance with the recommendations for chamber quantification by the American Society of Echocardiography’s Guidelines and Standard Committee and the Chamber Quantification Writing Group. Two-dimensional (2D) echocardiography images were obtained from LV apical four chamber (4C), LAX (long axis) and two-chamber (2C) view. All images were obtained during breath hold, and stored in cine loop format from 3 consecutive beats. The frame rate for images was between 50 and 90 frames/sec. All data were transferred to a workstation for further offline analysis. After defining the endocardial border manually, an epicardial tracing was automatically developed by the software system for each view. If the automatically obtained tracking segments were adequate for analysis, the software system was allowed to read the data, whereas analytically inadequate tracking segments were either corrected manually or excluded from the analysis. Strain measurements were reported as the peak longitudinal strain (LS) for 4C, LAX, and 2C views, and global strain (GS) was calculated by averaging the 3 apical views. The parasternal short-axis views at the base (tips of the mitral valve leaflets), the level of the papillary muscles, and the apex (with the minimum circular LV cavity at end-systole) were used for radial and circumferential strain and rotation analysis. The radial and circumferential strains and rotation were calculated as a strain average of 6 basal segments, 6 papillary segments, and 4 apical segments. The LV twist was calculated as an absolute apex-to-base difference in LV rotation. Measurement Variability: The intra-observer (M. K.) and inter-observer (A. B. N. and M. K.) variability for LV deformation parameters were assessed in all participants. For intra-observer assessment, the measurements were re-analyzed after 2 weeks. Intraclass correlation coefficients (ICC) for each measurement were used to quantify variability (An ICC 0.75 as excellent agreement). The degree of inter-observer and intra-observer agreement for LVtw, and LV strain measurements were perfect (All ICC values >0.75). Statistical Analysis: Descriptive statistics are presented as the mean standard deviation (SD) for continuous variables, median (interquartile range) for discontinuous variables, and frequencies and percentages for categorical variables. The clinical
LV Deformation in Ischemic Postconditioning
characteristics and laboratory data were analyzed with an independent t-test for continuous variables and chi-square tests or for categorical data. The variables were evaluated using visual (histograms, probability plots) and analytical methods (Kolmogorov–Simirnov/Shapiro–Wilk test) to determine whether they are normally distributed or not. For all statistical analyses, significance was assumed at P-value less than 0.05. Statistical analyses were performed using the SPSS software version 15 (SPSS Inc, Chicago, IL, USA). Results: A total of 22 consecutive healthy individuals (mean age was 28.9 4.2 years and female ratio was 36.4%) were included in the study. The echocardiographic characteristic of the study group before and after RIPC are presented in Table I. There were no significant difference between groups regarding E-wave, A-wave, systolic blood pressure, left ventricular ejection fraction (LVEF), heart rate, end-systolic volume (ESV) and end-diastolic volume (EDV) before and after RIPC. However, circumferential strain was significantly decreased, apical rotation was significantly increased and basal rotation was significantly decreased after RIPC. In the analysis, there was no significant difference between 4C-LS ( 20.5 2.3 vs. 19.9 1.6, respectively, P: 0.383), LAX-LS ( 19.9 2.1 vs. 19 2.2, respectively, P: 0.190), 2C-LS ( 21.2 2.6 vs. 20.2 2.2, respectively, P: 0.166) and GS ( 20.6 1.9 vs. 19.8 2, respectively, P: 0.201) values between before and after RIPC. Also there was no significant difference between 4C-LSr, LAX-LSr and 2C-LSr values between before and after RIPC
TABLE II Differences between Longitudinal Mechanics before and after RIPC Variables
Before RIPC
4C-LS, % LAX-LS, % 2C-LS, % 4C-Sr, sm 4C-Sr, em 4C-Sr, am LAX-Sr, sm LAX-Sr, em LAX-Sr, am 2C-Sr, sm 2C-Sr, em 2C-Sr, am GS, % GSr, sm GSr, em GSr, am
20.5 19.9 21.2 1.05 1.45 0.73 1.07 1.43 0.69 1.14 1.4 0.72 20.6 1.08 1.42 0.71
2.3 2.1 2.6 0.17 0.29 0.18 0.17 0.33 0.2 0.19 0.41 0.15 1.9 0.14 0.28 0.16
After RIPC 19.9 19 20.2 0.99 1.36 0.69 1.12 1.44 0.69 1.09 1.27 0.67 19.8 1.07 1.35 0.68
1.6 2.2 2.2 0.13 0.21 0.19 0.3 0.44 0.2 0.16 0.29 0.17 2 0.17 0.26 0.2
P-Value 0.383 0.190 0.166 0.162 0.267 0.439 0.654 0.511 0.998 0.434 0.216 0.369 0.201 0.762 0.427 0.598
4C = apical four-chamber view, LAX = apical long-axis view, 2C = apical two-chamber view, LS = longitudinal strain, Sr = strain rate, sm = systolic strain rate, em = early diastolic strain rate, am = late diastolic strain rate, GS = global strain, GSr = global strain rate; RIPC = remote ischemic postconditioning.
(Table II). While there were no significant differences in apical circumferential strain/strain rate measurements, basal circumferential strain was significantly decreased after RIPC ( 21.03 3.85 vs. 18.89 2.88, respectively, P: 0.043) (Table III) (Fig. 1). Besides, there were no significant differences in basal and apical radial strain measurements before and after RIPC.
TABLE III Differences between Circumferential and Rotational Mechanics before and after RIPC
TABLE I The Echocardiographic Characteristic of the Study Group before and after RIPC Variables
Before RIPC
SBP E, m/sec A, m/sec E/A Average Em, m/sec LVEF, % Heart rate, per min LVEDD-mm LVESD-mm LA-mm
117 0.82 0.67 1.25 0.13 66.5 73 47.4 28.8 28.7
12.5 0.25 0.14 0.35 0.03 3.3 9.1 2.6 2.3 2.9
After RIPC 115 0.79 0.64 1.26 0.12 66 72.1 47.6 29 28.9
10.0 0.16 0.10 0.28 0.04 2.9 9.2 2.6 2.2 3.1
P-Value 0.425 0.310 0.121 0.896 0.456 0.607 0.588 0.819 0.794 0.881
SBP = systolic blood pressure, LVEF = left ventricular ejection fraction, LVEDD = left ventricular end-diastolic diameter, LVESD = left ventricular end-systolic diameter, LA = left atrium; RIPC = remote ischemic postconditioning.
Variables
Before RIPC
Apical CS, % Apical CSr, sm Apical CSr, em Apical CSr, am Basal CS, % Basal CSr, sm Basal CSr, em Basal CSr, am Basal RS, % Apical RS, % Apical rotation Basal rotation Left ventricular twist
32.7 2.31 3.43 0.86 23 1.31 1.7 0.57 38.1 14.6 11.6 6.1 17.4
6.7 0.79 1.58 0.31 3.4 0.32 0.56 0.19 12.8 8.9 3.7 2.1 4.5
After RIPC 32.2 2.17 3.51 0.89 18.9 1.24 1.5 0.58 37.9 14.5 16.7 4.7 21.7
6.7 0.81 1.31 0.37 6.9 0.35 0.58 0.16 13.6 9.7 4.0 2.4 4.7
P-Value 0.784 0.575 0.922 0.787 0.017 0.489 0.247 0.912 0.866 0.916
