Protecting the aged heart during cardiac surgery: The potential benefits of del Nido cardioplegia

Del Nido Cardioplegia can be safely administered in high-risk coronary artery bypass grafting surgery after acute myocardial infarction: a propensity matched comparison

OBJECTIVE

Del Nido (DN) cardioplegia solution provides a depolarized hyperkalemic arrest lasting up to 60 minutes, and the addition of lidocaine may limit intracellular calcium influx. Single-dose DN cardioplegia solution may offer an alternative myocardial protection strategy to multi-dose cold whole blood (WB) cardioplegia following acute myocardial infarction (AMI).

METHODS

We retrospectively reviewed 88 consecutive patients with AMI undergoing coronary artery bypass (CABG) surgery with cardioplegic arrest between June 2010 to June 2012. Patients exclusively received WB (n = 40, June 2010-July 2011) or DN (n = 48, August 2011-June 2012) cardioplegia. Preoperative and postoperative data were retrospectively reviewed and compared using propensity scoring.

RESULTS

No significant difference in age, maximum preoperative serum troponin level, ejection fraction, and STS score was present between DN and WB. A single cardioplegia dose was given in 41 DN vs. 0 WB patients (p < 0.001), and retrograde cardioplegia was used 10 DN vs. 31 WB patients (p < 0.001). Mean cardiopulmonary bypass and cross clamp times were significantly shorter in the DN group versus WB group. Transfusion rate, length of stay, intra-aortic balloon pump requirement, post-operative inotropic support, and 30-day mortality was no different between groups. One patient in the WB group required a mechanical support due to profound cardiogenic shock.

CONCLUSIONS

DN cardioplegia may provide equivalent myocardial protection to existing cardioplegia without negative inotropic effects in the setting of acute myocardial infarction.

Assessing the safety of del Nido cardioplegia solution in adult congenital cases

PURPOSE

del Nido cardioplegia solution (CPS) has been successfully used for myocardial protection in the pediatric population. We propose this solution can be used safely in adult congenital patients. The proposed benefit of this solution is the avoidance of the need for repetitive interruption of the operation to administer multiple doses of standard cardioplegia.

METHODS

As part of a quality improvement initiative, 47 consecutive adult patients (mean age 40.9 years, range 18-71) undergoing congenital heart surgery were given del Nido CPS. Cardiac function was assessed pre- and post-operatively by echocardiography (ECHO). Inotrope use, troponin levels and restoration of cardiac rhythm were also evaluated.

RESULTS

The average duration of the longest ischemic time was 52.5 minutes ± 15.57 minutes. In patients receiving a single dose (40%, n=19) of CPS, the average ischemic time was 49.8 minutes ± 18.8 minutes. No patients demonstrated any ventricular electrical activity while the aorta was cross-clamped. Post-operative ECHO showed that 94% (n=44) had no change in ejection fraction from the pre-operative ECHO. Patients requiring inotropic support at the time of leaving the operating room (OR) was 43% (n=20). The percentage of patients requiring inotropic support twenty-four hours post-operatively was 17% (n=8). Spontaneous restoration of cardiac rhythm (without the need for defibrillation) after cross-clamp removal occurred in 91% (n=43) of patients. The average troponin T level post-op was 1.86 ± 2.9 µg/L.

CONCLUSIONS

del Nido CPS can be used for myocardial protection during adult congenital cardiac surgery without any apparent adverse effects. In addition, we were able to change our re-dosing protocol to 45 minutes with del Nido CPS compared to 20 minutes with our adult 4:1 blood CPS.

Myocardial protection using del nido cardioplegia solution in adult reoperative aortic valve surgery

BACKGROUND AND AIMS

The immediate postischemic period is marked by elevated intracellular calcium levels, which can lead to irreversible myocyte injury. Del Nido cardioplegia was developed for use in the pediatric population to address the inability of immature myocardium to tolerate high levels of intracellular calcium following cardiac surgery. Our aim in this study is to determine if this solution can be used safely and effectively in an adult, reoperative population.

METHODS

All patients undergoing isolated reoperative aortic valve replacement at our institution from 2010 to 2012 were retrospectively reviewed. Demographics, comorbidities, operative variables, postoperative complications, and patient outcomes were collected. Patients were divided into two groups based on cardioplegia strategy used: whole blood cardioplegia (WB, n = 61) and del Nido cardioplegia (DN, n = 52).

RESULTS

Mean age in the study was 73.4 ± 14.3 years and 86 patients were male (76.1%). Eighty-four patients had undergone prior coronary artery bypass graft (CABG) (74.3%). Patients in the DN group required significantly lower total volume of cardioplegia (1147.6 ± 447.2 mL DN vs. 1985.4 ± 691.1 mL WB, p < 0.001) and retrograde cardioplegia dose (279.3 ± 445.1 mL DN vs. 1341.2 ± 690.8 mL WB, p < 0.001). There were no differences in cross-clamp time, bypass time, postoperative complication rate, or patient outcomes between groups.

CONCLUSIONS

Del Nido cardioplegia use in an adult, reoperative aortic valve population offers equivalent postoperative outcomes when compared with whole blood cardioplegia. In addition, use of del Nido solution requires lower total and retrograde cardioplegia volumes in order to achieve adequate myocardial protection.

The Na+/Ca2+ exchange inhibitor SEA0400 limits intracellular Ca2+ accumulation and improves recovery of ventricular function when added to cardioplegia

Background

The Na⁺/Ca²⁺ exchange inhibitor SEA0400 prevents myocardial injury in models of global ischemia and reperfusion. We therefore evaluated its potential as a cardioplegia additive.

Methods

Isolated rat cardiomyocytes were exposed to hypoxia (45 min) followed by reperfusion. During hypoxia, cells were protected using cardioplegia with (n = 25) or without (n = 24) SEA0400 (1 μM), or were not protected with cardioplegia (hypoxic control, n = 8). Intracellular Ca²⁺ levels were measured using Ca²⁺ sensitive dye (fura-2 AM). Isolated rat hearts were arrested using cardioplegia with (n = 7) or without (n = 6) SEA0400 (1 μM) then reperfused after 45 min of ischemia. Left ventricular (LV) function, troponin release, and mitochondrial morphology were evaluated.

Results

Cardiomyocytes exposed to hypoxia without cardioplegia had poor survival (13%). Survival was significantly improved when cells were protected with cardioplegia containing SEA0400 (68%, p = 0.009); cardioplegia without SEA0400 was associated with intermediate survival (42%). Cardiomyocytes exposed to hypoxia alone had a rapid increase in intracellular Ca²⁺ (305 ± 123 nM after 20 minutes of ischemia). Increases in intracellular Ca²⁺ were reduced in cells arrested with cardioplegia without SEA0400; however cardioplegia containing SEA0400 was associated with the lowest intracellular Ca²⁺ levels (110 ± 17 vs. 156 ± 42 nM after 45 minutes of ischemia, p = 0.004). Hearts arrested with cardioplegia containing SEA0400 had better recovery of LV work compared to cardioplegia without SEA0400 (23140 ± 2264 vs. 7750 ± 929 mmHg.μl, p = 0.0001). Troponin release during reperfusion was lower (0.6 ± 0.2 vs. 2.4 ± 0.5 ng/mL, p = 0.0026), and there were more intact (41 ± 3 vs. 22 ± 5%, p < 0.005), and fewer disrupted mitochondria (24 ± 2 vs. 33 ± 3%, p < 0.05) in the SEA0400 group.

Conclusions

SEA0400 added to cardioplegia limits accumulation of intracellular Ca²⁺ during ischemic arrest in isolated cardiomyocytes and prevents myocardial injury and improves recovery of LV function in isolated hearts.

Myocardial protection against global ischemia with Krebs-Henseleit buffer-based cardioplegic solution

Background

The Krebs-Henseleit buffer is the best perfusion solution for isolated mammalian hearts. We hypothesized that a Krebs-Henseleit buffer-based cardioplegic solution might provide better myocardial protection than well-known crystalloid cardioplegic solutions because of its optimal electrolyte and glucose levels, presence of buffer systems, and mild hyperosmolarity.

Methods

Isolated Langendorff-perfused rat hearts were subjected to either global ischemia without cardioplegia (controls) or cardioplegic arrest for either 60 or 180 min, followed by 120 min of reperfusion. The modified Krebs-Henseleit buffer-based cardioplegic solution (mKHB) and St. Thomas’ Hospital solution No. 2 (STH2) were studied. During global ischemia, the temperatures of the heart and the cardioplegic solutions were maintained at either 37°C (60 min of ischemia) or 22°C (moderate hypothermia, 180 min of ischemia). Hemodynamic parameters were registered throughout the experiments. The infarct size was determined through histochemical examination.

Results

Cardioplegia with the mKHB solution at moderate hypothermia resulted in a minimal infarct size (5 ± 3%) compared to that in the controls and STH2 solution (35 ± 7% and 19 ± 9%, respectively; P < 0.001, for both groups vs. the mKHB group). In contrast to the control and STH2-treated hearts, no ischemic contracture was registered in the mKHB group during the 180-min global ischemia. At normothermia, the infarct sizes were 4 ± 3%, 72 ± 6%, and 70 ± 12% in the mKHB, controls, and STH2 groups, respectively (P < 0.0001). In addition, cardioplegia with mKHB at normothermia prevented ischemic contracture and improved the postischemic functional recovery of the left ventricle (P < 0.001, vs. STH2).

Conclusions

The data suggest that the Krebs-Henseleit buffer-based cardioplegic might be superior to the standard crystalloid solution (STH2).

Single dose myocardial protection technique utilizing del Nido cardioplegia solution during congenital heart surgery procedures

BACKGROUND

The single dose cardioplegia technique for myocardial protection during congenital heart surgery is a viable alternative to multidose protocols.

METHODS

Thirty-four pediatric patients with aortic cross clamp times greater than 90 minutes were grouped by modified adult (MA) multidose solution or del Nido (dN) single dose solution. Also, data from eight patients where the cross clamp times were greater than two hours on one dose of dN solution were included.

RESULTS

In the 90-minute plus arm of the study, there were no significant differences between the groups when comparing the risk adjustment for congenital heart surgery (RACHS) (p=0.6), cardiopulmonary bypass times (CPB) (p=0.5), aortic cross camp times (p=0.5), weights (p=0.7) and number of intraoperative exogenous blood units (p=0.5). There were significant differences between the groups (p<0.05) in the number of cardioplegia doses and with perioperative glucose levels. In the greater than two hours group, the incidence of complete heart block (CHB) was 0.125% and there were no deaths or mechanical circulatory support (MCS) devices used.

CONCLUSION

del Nido cardioplegia solution is a reasonable tool for myocardial protection during congenital heart surgery that significantly decreased the number of cardioplegic interventions and perioperative glucose values in our study groups.