On-Pump Beating Heart Versus Hypothermic Arrested Heart Valve Replacement Surgery

Changes in SedLine-derived processed electroencephalographic parameters during hypothermia in patients undergoing cardiac surgery with cardiopulmonary bypass

Objective

Processed electroencephalography (pEEG) is used to monitor depth-of-anesthesia during cardiopulmonary bypass (CPB). The SedLine device has been recently introduced for pEEG monitoring. However, the effect of hypothermia on its parameters during CPB is unknown. Accordingly, we aimed to investigate temperature-induced changes in SedLine-derived pEEG parameters during CPB.

Design

Prospective observational study.

Setting

Cardiac surgery operating theatre.

Participants

28 patients undergoing elective cardiac surgery with CPB.

Interventions

We continuously measured patient state index (PSI), suppression ratio (SR), bilateral spectral edge frequency (SEF) and temperature. We used linear mixed modelling with fixed and random effects to study the interactions between pEEG parameters and core temperature.

Measurements and main results

During CPB maintenance, the median temperature was 32.1°C [interquartile range (IQR): 29.8-33.6] at the end of cooling and 32.8°C (IQR: 30.1-34.0) at rewarming initiation. For each degree Celsius change in temperature during cooling and rewarming the PSI either decreased by 0.8 points [95% confidence interval (CI): 0.7-1.0; p < 0.001] or increased by 0.7 points (95% CI: 0.6-0.8; p < 0.001). The SR increased by 2.9 (95% CI: 2.3-3.4); p < 0.001) during cooling and decreased by 2.2 (95% CI: 1.7-2.7; p < 0.001) during rewarming. Changes in the SEF were not related to changes in temperature.

Conclusions

During hypothermic CPB, temperature changes led to concordant changes in the PSI. The SR increased during cooling and decreased during rewarming. Clinicians using SedLine for depth-of-anesthesia monitoring should be aware of these effects when interpreting the PSI and SR values.

Application of lower sternal incision with on-pump, beating heart intracardiac procedures in congenital heart disease

BACKGROUND

The purpose of this study was to explore the application of lower sternal incision with on-pump, beating heart intracardiac procedures for the treatment of congenital heart disease.

METHODS

A total of 106 cases with congenital heart disease were performed with lower sternal incision under the beating heart condition. The sternum was sawed open to the third sternocostal joint through a small incision in the lower sternum. Cardiopulmonary bypass was developed without aortic cross-clamping. The simultaneous left atrium and ventricle suction and integrating sequential deairing procedure was established to improve the exposure of the surgical field and intraoperative de-airing. We also randomly selected 100 patients with similar disease and age as controls. These control patients underwent middle sternal incision surgery with arresting heart.

RESULTS

The results showed that all the patients were successfully completed with the surgery without death and serious complications, eg, air embolism, residual shunt, and complete atrioventricular block. The operative and cardiopulmonary bypass time in the experimental group was not significantly different from that in the control group. The length of the skin incision in the experimental group was shortened by 4.8 cm compared to that in the control group. The incidence of sternal deformity in patients under 3 years old in the experimental group was significantly lower than that in the control group.

CONCLUSIONS

Lower sternal incision with beating heart can reduce the surgical injury, simplify the operation procedure, and improve the therapeutic efficacy. It is a safe and effective approach for the treatment of congenital heart disease.

Cardioplegic strategies to protect the hypertrophic heart during cardiac surgery

Cardioplegic arrest and cardiopulmonary bypass are key triggers of myocardial injury during aortic valve surgery. Cardioplegic ischaemic arrest is associated with disruption to metabolic and ionic homeostasis in cardiomyocytes. These changes predispose the heart to reperfusion injury caused by elevated intracellular reactive oxygen species and calcium. Cardiopulmonary bypass is associated with an inflammatory response that can generate systemic oxidative stress which, in turn, provokes further damage to the heart. Techniques of myocardial protection are routinely applied to all hearts, irrespective of their pathology, although different cardiomypathies respond differently to ischaemia and reperfusion injury. In particular, the efficacy of cardioprotective interventions used to protect the hypertrophic heart in patients with aortic valve disease remains controversial. This review will describe key cellular changes in hypertrophy, response to ischaemia and reperfusion and cardioplegic arrest and highlight the importance of optimising cardioprotective strategies to suit hypertrophic hearts.

Comparison of neurocognitive functions after beating-heart mitral valve replacement without aorta cross-clamping and after standard mitral valve replacement with cardioplegic arrest

BACKGROUND

The aim of this study was to compare the postoperative long-term neurocognitive functions of patients who under-went beating-heart mitral valve replacement on cardiopulmonary bypass (CPB) without aorta cross-clamping with those of patients who underwent mitral valve replacement via the classic method.

METHODS

The study group included 25 randomly selected patients who underwent beating-heart mitral valve surgery. During the same period, 25 patients were randomly selected as controls to undergo mitral valve replacement procedures via the standard ascending aorta-cannulation technique. The clinical and postoperative (2 months) neurocognitive functional data of both groups were compared.

RESULTS

Neurologic deficit was observed in neither group during the postoperative period. There were no statistically significant differences between the control and the study groups with respect to Hospital Anxiety and Depression Scale (HADS) results (HADS: anxiety, P = .653; HADS: depression, P = .225), in the right hemispheric cognitive function test results (Raven's Standard Progressive Matrices [RSPM] and Line Orientation Test [LOT] tests: RSPM, P = .189), and in the left hemispheric cognitive function test results (the Ray Auditory Verbal Learning [RAVL] and Stroop Color-Word Test [SCWT] tests: SCWT 1 time, P = .300; SCWT 2 time, P = .679; SCWT 3 time, P = .336; SCWT 4 time, P = .852; SCWT 5 time, P = .416; RAVL total verbal learning, P = .167; RAVL immediate recall, P = .791; RAVL distraction trial, P = .199; RAVL retention, P = .174; RAVL delayed recall, P = .111; RAVL recognition, P = .282; SCWT 4 mistake, P = .306; SCWT 4 reform, P = .066; SCWT 5 mistake, P = .236; SCWT 5 reform, P = .301).

CONCLUSIONS

The technique of mitral valve replacement with normothermic CPB without cross-clamping of the aorta may be safely used for the majority of patients requiring mitral valve replacement without causing deterioration in neurocognitive functions.

Beating heart continuous coronary perfusion for valve surgery: what next for clinical trials?

Prior to the introduction of cardioplegia, beating heart continuous coronary perfusion (BHCCP) was the only available method of myocardial protection. Currently, cardiac surgery on cardiopulmonary bypass with cardioplegic arrest is the gold standard strategy. Cardioplegic arrest provides an easier and safer way to operate on a still heart. It enables the performance of a broader range of cardiac procedures, and avoids the potential difficulties of continuous perfusion on a beating heart. Despite the overall effectiveness and safety of cardioplegia, some adverse effects remain, mainly due to the insult of ischemia, which results in ischemic reperfusion injury. As a result BHCCP has seen a revival as an alternative to cardioplegia for performing complex valvular surgery. Increasing experience reporting safety and efficacy of BHCCP is being published. However, despite the reported advantages, current available evidence validating safety and efficacy of BHCCP is controversial. This article provides an overview of BHCCP highlighting the current best available evidence supporting this strategy, concerns, controversies and potential areas for further research.

Beating-Heart Valve Surgery: A Systematic Review

Beating-heart continuous coronary perfusion (BHCCP) has been promoted as an alternative to the technique of cardioplegic arrest in valve surgery. Its potential advantage is the elimination of cardioplegia and the corollary risk of ischemic reperfusion injury. The use of CCP has been recommended especially when performing more complex operations, such as mitral valve repair, and particularly as surgeons become more familiar with beating-heart coronary surgery. We conducted a systematic review to assess the strength of the evidence supporting the efficacy of BHCCP compared to cardioplegia in valve surgery. Thirty nine reports were identified. Of these, only two were randomized control trials. Overall the studies were generally of poor quality and had a low evidence level. In those studies, mortality and major morbidity from BHCCP were within acceptable levels, nevertheless, there was no advantage over cardioplegic arrest. On the other hand there is weak evidence that it may reduce functional and biochemical markers of myocardial injury. In conclusion, BHCCP is an operative strategy in valve surgery with some potential benefits. There is, however a need for a high quality, prospective, randomized control trial to establish the exact role for BHCCP in complex valve surgery.