Scholarly article on topic 'Effect of terminal warm reperfusion (hot shot) and remote ischemic preconditioning, either separately or combined, on myocardial recovery in adult cardiac surgery'

Effect of terminal warm reperfusion (hot shot) and remote ischemic preconditioning, either separately or combined, on myocardial recovery in adult cardiac surgery Academic research paper on "Basic medicine"

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{"Myocardial protection" / Cardioplegia / "Hot shot" / "Remote ischemic preconditioning"}

Abstract of research paper on Basic medicine, author of scientific article — Mohamed Elgariah, Mohamed Abo El Nasr, Hosam Fawzy, Ehab Wahby, Abdelhady Taha

Abstract Background Reperfusion injury is a major contributor to morbidity and mortality after cardiac surgery. Among the myocardial protective modalities, terminal warm reperfusion (hot shot) and remote ischemic pre-conditioning techniques were found to protect myocardial function and improve better postoperative outcomes. The aim of this study was to compare the effect of terminal hot shot cardioplegia, the effect of remote ischemic preconditioning and the effect of both techniques on myocardial recovery after adult cardiac surgery. Methods One hundred forty-five patients were divided into four groups comparing hot shot group, remote ischemic preconditioning group, combined hot shot and remote ischemic preconditioning group and the control group. The data collected included preoperative demographic and clinical characteristics, intraoperative data and postoperative short term outcome including inhospital mortality. Results Patients of the combined group were found to have significantly better outcome including fewer ventricular arrhythmias, less intra-operative need of intra-aortic balloon pump, low cardiac output, and less length of ICU stay. The in-hospital mortality showed a significant difference between the 4 groups. Among patients without hot shot, the incidence of postoperative temporary epicardial pacing was higher and decreased in patients underwent hot shot and remote ischemic preconditioning but didn't reach a statistical significance. Conclusions Both remote ischemic preconditioning and terminal hot shot reperfusion before removal of the aortic cross clamping improved outcome of on-pump adult cardiac surgery patients. There was a significant effect on the in-hospital mortality and there were fewer incidences of arrhythmias and less requirement for postoperative inotropic support with this technique.

Academic research paper on topic "Effect of terminal warm reperfusion (hot shot) and remote ischemic preconditioning, either separately or combined, on myocardial recovery in adult cardiac surgery"

ELSEVIER

Journal of the Egyptian Society of Cardio-Thoracic Surgery xxx (2017) 1—6

Contents lists available at ScienceDirect

Journal of the Egyptian Society of Cardio-Thoracic Surgery

journal homepage: http://www.journals.elsevier.com/journal-of-the-egyptian-society-of-cardio-thoracic-surge ry/

Effect of terminal warm reperfusion (hot shot) and remote ischemic preconditioning, either separately or combined, on myocardial recovery in adult cardiac surgery

Mohamed Elgariah, Mohamed Abo El Nasr*, Hosam Fawzy, Ehab Wahby, Abdelhady Taha

Department of Cardiothoracic Surgery, Faculty of Medicine, Tanta University, Egypt

ARTICLE INFO ABSTRACT

Background: Reperfusion injury is a major contributor to morbidity and mortality after cardiac surgery. Among the myocardial protective modalities, terminal warm reperfusion (hot shot) and remote ischemic pre-conditioning techniques were found to protect myocardial function and improve better postoperative outcomes. The aim of this study was to compare the effect of terminal hot shot cardioplegia, the effect of remote ischemic preconditioning and the effect of both techniques on myocardial recovery after adult cardiac surgery.

Methods: One hundred forty-five patients were divided into four groups comparing hot shot group, remote ischemic preconditioning group, combined hot shot and remote ischemic preconditioning group and the control group. The data collected included pre-operative demographic and clinical characteristics, intraoperative data and postoperative short term outcome including inhospital mortality.

Results: Patients of the combined group were found to have significantly better outcome including fewer ventricular arrhythmias, less intra-operative need of intra-aortic balloon pump, low cardiac output, and less length of ICU stay. The in-hospital mortality showed a significant difference between the 4 groups. Among patients without hot shot, the incidence of postoperative temporary epicardial pacing was higher and decreased in patients underwent hot shot and remote ischemic preconditioning but didn't reach a statistical significance.

Conclusions: Both remote ischemic preconditioning and terminal hot shot reperfusion before removal of the aortic cross clamping improved outcome of on-pump adult cardiac surgery patients. There was a significant effect on the in-hospital mortality and there were fewer incidences of arrhythmias and less requirement for postoperative inotropic support with this technique.

© 2017 Publishing services by Elsevier B.V. on behalf of The Egyptian Society of Cardiothoracic Surgery. This is an open access article under the CC BY-NC-ND license (http://

creativecommons.org/licenses/by-nc-nd/4.0/).

Article history:

Received 4 June 2017

Received in revised form 13 July 2017

Accepted 21 July 2017

Available online xxx

Keywords:

Myocardial protection

Cardioplegia

Hot shot

Remote ischemic preconditioning

* Corresponding author. E-mail address: dr_mmaboelnasr@yahoo.com (M. Abo El Nasr). Peer review under responsibility of The Egyptian Society of Cardio-thoracic Surgery.

http://dx.doi.org/10.1016/jjescts.2017.07.005

1110-578X/© 2017 Publishing services by Elsevier B.V. on behalf of The Egyptian Society of Cardio-thoracic Surgery. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction

Even though advances in surgical technique, anesthesia, myocardial protection and postoperative care have reduced the risk involved in open heart surgery; compromised ventricular function and arrhythmias still occur in cardiac surgery patients [1].

Cardiac surgeons and anesthesiologists have sought more optimal methods to protect the myocardium from ischemia-reperfusion injury. It has been well established that antegrade cardioplegia may fail to give adequate protection to all myocardial regions [2]. Retrograde cardioplegia has been proposed as an alternative or additive to antegrade cardioplegia [3], but studies showed that combined delivery of cardioplegia did not provide adequate myocardial protection especially in coronary artery disease cases [4—7]. Thus, consideration of additional myocardial protection strategies is necessary.

Advances in cardioplegic techniques included intermittent antegrade cold blood cardioplegia with terminal warm reperfusion (hot-shot) which has been shown to improve myocardial protection in open heart surgery [8]. Terminal Warm reperfusion (hot shot) refers to the administration of terminal warm perfusate before removing the aortic cross clamp aiming to wash out anaerobic metabolites from the coronary circulation of the arrested heart and to minimize the ischemia-reperfusion myocardial injury and to achieve resumption of effective electro-mechanical myocardial activity [9].

Remote ischemic preconditioning depends on protection of the heart by applying repetitive ischemia and reperfusion to an organ remote from the heart. Ischemic preconditioning was first described by Przyklenk et al. [10], who found that the size of myocardial infarction due to left anterior descending artery occlusion was reduced after intermittent occlusion of circumflex artery. This idea was taken and extended to investigate the effect of ischemic stimulus to an organ remote from the heart on myocardial protection [11—14].

We aimed to compare the effect of terminal hot shot cardioplegia, the effect of remote ischemic preconditioning and the effect of both techniques on myocardial recovery after adult cardiac surgery.

2. Patients and methods

2.1. Study population

One hundred forty-five patients who underwent either valve surgery or coronary artery bypass grafting (CABG) at Cardiothoracic Surgery Department in Tanta University Hospital, Tanta, Egypt between December 2014 and December 2016 were enrolled in this study. Data were prospectively collected and analyzed. The study population was adult cardiac surgery patients who were electively scheduled for valve surgery or CABG. Patients were divided into four groups comparing first group (control group), the second group (Hot shot group) and the third group (remote ischemic preconditioning (RIPC) group) and the fourth group (combined group). Informed consent was taken from patients involved in the study. The protocol was approved by the Tanta faculty of medicine ethical committee.

2.2. Outcome measures

2.2.1. intraoperative variables included

The time needed by the heart from aortic declamping to restoration of effective electro-mechanical contraction, the heart rate and rhythm after aortic declamping, the occurrence of ST-segment changes in the ECG, the mean arterial blood pressure, the arterial blood pH changes, the need for defibrillation and the response, the need for inotropic support, the need for anti-arrhythmic drugs, the need for artificial pacing, the need for reentry to cardiopulmonary bypass (CPB) for circulatory support, and the need for intra-aortic balloon pump (IABP) circulatory support.

2.2.2. The postoperative (ICU) variables included

The serum troponin I level, the mean arterial blood pressure, the heart rate & rhythm, the ST-segment changes in the ECG, the need for high inotropic support, the need for anti-arrhythmic drugs, the hours of postoperative mechanical ventilation, the length of ICU stay and the incidence of in-hospital mortality.

2.3. Surgical management

Standard anesthetic and operative procedures were used as all the patients had conventional on-pump cardiac surgery in both prosthetic valve replacement cases and CABG cases.

In the RIPC group and in the combined group the patient had repeated intermittent, transient, reversible, and non-lethal upper limb ischemia by inflating a pressure cuff to 200 mmHg around the arm for 4 cycles of 5 min ischemia alternating with 5 min reperfusion starting from the time of induction of anesthesia.

In the hot shot group and in the combined group, the patient received 250 ml of warm perfusate (normothermic car-dioplegia) at 37°C temperature infused to the aortic root via the antegrade cardioplegia cannula started 3—5 min prior to aortic decalmping with a constant flow rate of 150 ml/min for 2 min.

The composition of the cold cardioplegia given to all groups was per liter of Ringer's solution: Sodium 97 mEq, Potassium 15 mEq, Chloride 92 mEq, Calcium 0.07 mEq, Bicarbonate 20 mEq, Glucose 25 g, Mannitol 12.5 g and Lidocaine HCl 120 mg. Temperature of cardioplegia was 4 C and given initially at a dose of 20 ml/kg to be repeated every 25 min as 10 ml/kg.

2.4. Statistical analysis

The statistical analyses were performed using SPSS version 20 for Windows (SPSS, Chicago, IL). Continuous variables were expressed as mean ± std, whereas categorical variables were expressed in terms of percentages and frequencies. For continuous variables, analysis of variance (ANOVA) was used to compare means of different groups followed by post-hoc tukey test. For comparing categorical variables, chi-square test was used. P values of <0.05 were considered statistically significant.

3. Results

A total of 145 patients were divided into 4 groups, control group (group 1) 37 patients, hot shot group (group 2, 36 patients), RIPC patients group (group 3, 36 patients) and the combined group (group 4, 36 patients). The four groups were matched in the demographic profile. Regarding preoperative variables including age, sex and patients' comorbidities, there was no significant difference between 4 groups as shown in Table .

A significant difference was found between the 4 groups regarding the myocardial electrophysiological recovery, shown as the time needed by the heart from declamping to restoration of effective myocardial electromechanical contraction (time to regular mechanical activity) with the terminal hot shot group showed better protection than the control group.

Statistical significant difference was found in operative variables by comparing control group to the other 3 groups including the rates of arrhythmias (heart block, atrial fibrillation, ventricular fibrillation),the rate of occurrence of ST-segment ECG changes after aortic declamping, the need for a high inotropic support after aortic declamping, the need for antiar-rhythmic drugs, the postoperative serum troponin level elevation, the need of IABP insertion, frequency of use of defibrillator, time to regular mechanical activity, the heart rate after restoration of myocardial electromechanical activity, the mean arterial blood pressure (ABP) after declamping and total CPB time as shown in Tables 2 and 3.

Regarding post-operative outcome variables, by comparing hot shot group, combined group and remote ischemic preconditioning group to control group, we found that the rates of myocardial infarction, troponin I, inotropic support, the occurrence of post-operative ST-segment changes, postoperative mean ABP, postoperative heart rate (HR) & rhythm, length of postoperative ICU stay, the postoperative need for a high inotropic support in the ICU, and hospital deaths were statistically significant as shown in Tables 4 and 5. Hot shot group had the best postoperative length of mechanical ventilation and ICU stay and the best postoperative mean arterial blood pressure. We also found that hot shot group had the shorter aortic cross clamp time, CPB time and reperfusion time.

4. Discussion

Our study was a single center prospective comparative study between the effect of infusion of terminal warm reperfusion (hot shot) before removal of the aortic cross clamp, the effect of RIPC and the effect of both techniques together on myocardial recovery in elective adult cardiac surgery.

In our study, comparison of myocardial protection with cold crystalloid cardioplegia without hot shot (the control group) and the addition of terminal hot shot showed better recovery of myocardial electrophysiological activity in both CABG and valve replacement in hot shot group and more patients spontaneously resumed sinus or the preoperative rhythm after the operation.

In Teoh's et al. study [15], they compared cold blood cardioplegia to cold blood cardioplegia followed by a hot shot. They found that there was preservation of energy stores, improvement of myocardial metabolic recovery, improvement in diastolic function and washing out products of anaerobic metabolism in hot shot group.

Table 1

Pre-operative variables in different studied groups.

Control group (n = 37) Hot shot Group (n = 36) RIPC group (n = 36) Combined group (n = 36) P value

Age (mean ± std) Sex Female 40.41 ± 12.85 43.69 ± 12.27 44.67 ± 9.62 45.39 ± 13.19 0.305

68 16 (43.2) 17 (47.2) 19 (52.8) 16 (44.4) 0.853

Male 77 21 (56.8) 19 (52.8) 17 (47.2) 20 (55.6)

Incidence of pre-operative co-morbidity

HTN 2 (5.4) 1 (2.8) 3(8.1) 1 (2.8) 0.648

DM 3(8.1) 2 (5.6) 1 (2.8) 2 (5.6) 0.787

Obesity 1 (2.7) 1 (2.8) 3(8.1) 1 (2.8) 0.555

TIA 2 (5.4) 2 (5.6) 2 (5.6) 3(8.1) 0.949

(RIPC remote ischemic preconditioning; HTN hypertension; DM Diabetes mellitus; TIA Transient ischemic attacks).

Table 2

Intraoperative continuous variables in different studied groups.

Control group (n = 37)

Hot shot Group (n = 36)

RIPC group (n = 36)

Combined group (n = 36)

P value

Total CPB time(min)

(mean ± std) 161.05 ± 101.40 Hot shot vs control (p value < 0.001*) Aortic cross clamping time(min) (mean ± std) 96.49 ± 44.95 Hot shot vs control (p value < 0.001*) Reperfusion time(min) (mean ± std) 22.05 ± 14.23 Hot shot vs control (p value < 0.001*) Time to regular mechanical activity (min) (mean ± std) 17.35 ± 16.04 Hot shot vs control (p value < 0.001*)

91.81 ± 22.41 102.75 ± 46.14

RIPC vs control (p value < 0.001*)

63.42 ± 15.69 70.19 ± 28.23

RIPC vs control (p value 0.005*)

12.58 ± 4.43 14.81 ± 6.58

RIPC vs control (p value 0.003*)

6.78 ± 3.35 8.14 ± 4.22

RIPC vs control (p value < 0.001*)

Heart rate after restoration of myocardial electromechanical activity (beats/min) (mean ± std) 110.68 ± 21.93 91.83 ± 11.84 98.56 ± 12.01

Hot shot vs control (p value < 0.001*) RIPC vs control (p value 0.011*)

Mean ABP after declamping (mmHg)

(mean ± std) 58.78 ± 11.33 67.50 ± 7.42 66.39 ± 6.28

Hot shot vs control (p value < 0.001*) RIPC vs control (p value < 0.001*)

Number of DC shocks needed after aortic declamping (frequency of use of defibrillator)

(mean ± std) 3.83 ± 1.70 2.06 ± 1.21 2.23 ± 0.82

Hot shot vs control (p value < 0.001*) RIPC vs control (p value < 0.001*)

105.92 ± 67.00 Combined vs control

73.25 ± 37.88 Combined vs control

14.39 ± 7.14 Combined vs control

8.17 ± 10.92 Combined vs control

89.31 ± 19.09 Combined vs control

68.47 ± 8.52 Combined vs control

2.25 ± 1.29 Combined vs control

(p value (p value (p value (p value (p value (p value (p value

<0.001* 0.002*)

<0.001* 0.017*)

<0.001* < 0.001*)

<0.001* < 0.001*)

<0.001* < 0.001*)

<0.001* < 0.001*)

<0.001* < 0.001*)

(RIPC remote ischemic preconditioning; CPB cardiopulmonary bypass, ABP arterial blood pressure).

* Significant (p value < 0.05).

Table 3

Intraoperative categorical variables in different studied groups.

Control group (n = 37) Rhythm after aortic declamping Sinus 115 24(64.9) 32(88.9)

Arrhythmia 30 13(35.1) 4(11.1)

ST-segment changes in ECG after aortic declamping No 129 28 (75.7) 35 (97.2)

Yes 16 9 (24.3) 1 (2.8)

pH changes (metabolic acidosis) after aortic declamping No 118 27 (73) 33 (91.7)

Yes 27 10(27) 3(8.3)

Need for high inotropic support after aortic declamping No 124 26 (70.3) 34 (94.4)

Yes 12 11 (29.7) 2 (5.6)

Intra-operative need for anti-arrhythmic drugs after aortic declamping No 115 23 (62.2) 31 (86.1)

Yes 30 14 (37.8) 5 (13.9)

Need for temporary cardiac pacing after aortic declamping No 127 29 (78.4) 33 (91.7)

Yes 18 8 (21.6) 3 (8.3)

Need for IABP institution

No 136 30(81.1) 35 (97.2)

Yes 9 7 (18.9) 1 (2.8)

(RIPC remote ischemic preconditioning; IABP Intra-aortic balloon pump).

* Significant (p value < 0.05).

RIPC group (n = 36) Combined group (n = 36) P value

27 (75) 32 (88.9) 0.028*

9(25) 4(11.1)

33 (91.7) 33 (91.7) 0.021*

3 (8.3) 3 (8.3)

28 (77.8) 30 (83.3) 0.200

8 (22.2) 6(16.7)

31 (86.1) 33 (91.7) 0.016*

5 (13.9) 3 (8.3)

30 (83.3) 31 (86.1) 0.029*

6(16.7) 5 (13.9)

31 (86.1) 34 (94.4) 0.167

5 (13.9) 2 (5.6)

36(100) 35 (97.2) 0.003*

0 (0) 1 (2.8)

Hot shot Group (n = 36)

The clinical implications of our study results and findings go in the same direction as Teoh and colleagues' findings, who found that a hot shot immediately prior to the release of the cross clamp resulted in better myocardial electromechanical recovery. In Lubicz's study [16], using warm oxygenated cardioplegia supports the beneficial effects in terms of freedom from ventricular fibrillation (VF), conduction defects, cardiac failure and myocardial infarction (MI). Cardiac function was resumed after 15 min of warm reperfusion administration.

On the other hand, Edwards et al. [17] included a heterogeneous group of patients to see if there are systematic benefits attributable to the "hot shot." They have failed to show any difference in the postoperative release of the MB2 iso-form of creatine kinase (CK), total CK-MB activity, or troponin-T between modified "hot shot" and unmodified reperfusion. Despite being large study, it was the only study that failed to show the benefits of using hot shot protocol and this can be explained by the different variables they have used. Crucially, the vast majority of randomized control trials investigating the effects of RIPC are relatively small proof of concept studies and have often given discordant results for potential reasons.

Table 4

Post-operative continuous variables in different studied groups.

Control group (n = 3l)

Hot shot Group (n = 36)

RIPC group (n = 36)

Combined group (n = 36)

P value

68.64 ± 6.41 66.28 ± 7.29

RIPC vs control (p value 0.010*)

Postoperative mean ABP (mmHg)

(mean ± std) 58.24 ± 14.25 Hot shot vs control (p value < 0.001*) Postoperative heart rate (beats/min) (mean ± std) 103.78 ± 26.88 90.78 ± 8.83 97.25 ± 12.49

Hot shot vs control (p value 0.013*) RIPC vs control (p value 0.422)

Duration post-operative mechanical ventilation (hours)

(mean ± std) 10.24 ± 7.23 7.78 ± 4.18 9.33 ± 4.88

Duration of postop ICU stay (days)

(mean ± std) 4.51 ± 2.52 3.64 ± 1.25 3.81 ± 1.26

Hot shot vs control (p value 0.133) RIPC vs control (p value 0.296)

Total hospital stay (days)

(mean ± std) 14.3 ± 2.1 7.6 ± 1.8 10.2 ± 2.3

Hot shot vs control (p value < 0.001*) RIPC vs control (p value < 0.001*)

67.08 ± 13.49 <0.001*

Combined vs control (p value < 0.004*)

87.23 ± 19.27 <0.001*

Combined vs control (p value < 0.001*)

10.56 ± 15.61 0.574

3.36 ± 1.51 0.034*

Combined vs control (p value 0.022*)

7.4 ± 1.5 <0.001*

Combined vs control (p value < 0.001*)

(RIPC remote ischemic preconditioning; ABP Arterial blood pressure). * Significant (p value < 0.05).

Table 5

Post-operative categorical variables in different studied groups.

Control group (n = 37)

Post-operative serum troponin level elevation

No 123 26 (70.3) 34 (94.4)

Yes 22 11 (29.7) 2 (5.6)

Post-operative ST-segment changes in ECG

No 131 29 (78.4) 35 (97.2)

Yes 14 8 (21.6) 1 (2.8)

Post-operative need for high inotropic support

No 116 23 (62.2) 32 (88.9)

Yes 29 14 (37.8) 4(11.1)

Post-operative need for antiarrhythmic drugs

No 101 22 (59.5) 29 (80.6)

Yes 44 15 (40.5) 7 (19.4)

Post-operative heart rhythm

Sinus 115 24 (64.9) 32 (88.9)

Arrhythmia 30 13 (35.1) 4(11.1)

Incidence of occurrence of post-operative complications (in the ICU)

Bleeding 2 (5.4) 2 (5.6)

Re-exploration 1 (2.7) 1 (2.8)

Heart block 3(8.1) 2 (5.6)

Stroke 1 (2.7) 1 (2.8)

Hospital mortality

No 129 27 (73) 36 (100)

Yes 16 10(2l) 0 (0)

(RIPC remote ischemic preconditioning).

* Significant (p value < 0.05).

RIPC group (n = 36) Combined group (n = 36) P value

31 (86.1) 32 (88.9) 0.027

5 (13.9) 4(11.1)

34 (94.4) 33 (91.7) 0.032

2 (5.6) 3 (8.3)

31 (86.1) 30 (83.3) 0.017

5 (13.9) 6(16.l)

23 (63.9) 27 (75) 0.180

13 (36.1) 9 (25)

27 (75) 32 (88.9) 0.028

9(25) 4(11.1)

2 (5.6) 1 (2.8) 0.930

1 (2.8) 2 (5.6) 0.892

3 (8.3) 3 (8.3) 0.961

1 (2.8) 1 (2.8) 1.000

34 (94.4) 32 (88.9) 0.002

2 (5.6) 4(11.1)

Hot shot Group (n = 36)

In addition, a significant number of systemic reviews and meta-analyses in patients underwent cardiac surgery have been conducted: the overall conclusion confirmed the beneficial effects of RIPC on peri-operative myocardial injury reduction, however no statistically significant improvement of clinical outcomes was observed, including the mortality rate, perioperative MI, renal failure, stroke, mesenteric ischemia, hospital or ICU stay. The first study done by Li et al. [18] to describe the impact of RIPC on patients' morbidity and mortality in the context of cardiac surgery reported no post-operative death in either preconditioned or control patients 30 days after elective aortic valve replacement, mitral valve surgery or double valve replacement.

Similarly, no significant difference in major cardiac and cerebro-vascular events was found after one month post-operatively in two other studies involving patients underwent CABG surgery with crystalloid cardioplegia [19,20]. However, in our study we found that RIPC reduced the rate of death, MI, arrhythmia and the need for inotropic support.

Our study showed the myocardial protective effects of RIPC in patients underwent valve replacement surgery or CABG surgery through decreasing the serum troponin level postoperatively, also reducing the inotropic support needed post-operatively for these patients and improving the ventilation time and ICU stay time. This was similar to results given by Taha et al. who confirmed the myocardial protective effect of remote ischemic preconditioning [21].

In terms of the inotropic support requirements, our study was consistent with Cheung et al., who found that there was a significant reduction in inotropic support post-operatively [22].

Hong et al. [23] studied RIPC in 70 elective off-pump CABG patients via lower-limb ischemia (4 cycles of 5 min) and reported that there was 50% reduction in cardiac enzymes postoperatively. In contrast to this study, Lucchinetti et al. [24] concluded that no difference in cardiac enzymes postoperatively in patients subjected to RIPC.

Our study was in contrast to that of Thielmann et al. [20], who found that there was a non-significant decrease in inotropic support requirement postoperatively. This may be because the mean age of the patients in our study was lower than that in these studies and different types of operation of our study made the RIPC protocol more effective in decreasing the inotropic requirement.

Our study was unique in evaluation of the combined group as the addition of both the hot shot and the RIPC together in the same group of patients (the combined group) had not been done before.

The combined group had lower need for a high inotropic support after aortic declamping and this can be explained by the earlier and better recovery of myocardial contractility and the lower incidence of ST-segment ischemic ECG changes after aortic declamping (better myocardial protection). The postoperative elevation of serum troponin level was less in the combined group than in the control group and this could be explained by the lower incidence of occurrence of both intraoperative and post-operative ischemia with better myocardial protection.

5. Conclusions

From our study, we can conclude that terminal hot shot and remote ischemic preconditioning offer a powerful car-dioprotective strategy for reducing and attenuating perioperative and peri-procedural myocardial injury in patients undergoing CABG surgery and prosthetic valve surgery.

The simplicity and non-invasive nature, as well as the flexibility of the timing of the remote ischemic conditioning stimulus and the simplicity and availability of terminal hot shot make it feasible to apply in adult cardiac surgery.

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