Single-Dose Lignocaine-Based Blood Cardioplegia in Single Valve Replacement Patients

Cardioplegia between Evolution and Revolution: From Depolarized to Polarized Cardiac Arrest in Adult Cardiac Surgery

Despite current advances in perioperative care, intraoperative myocardial protection during cardiac surgery has not kept the same pace. High potassium cardioplegic solutions were introduced in the 1950s, and in the early 1960s they were soon recognized as harmful. Since that time, surgeons have minimized many of the adverse effects by lowering the temperature of the heart, lowering K⁺ concentration, reducing contact K⁺ time, changing the vehicle from a crystalloid solution to whole-blood, adding many pharmacological protectants and modifying reperfusion conditions. Despite these attempts, high potassium remains a suboptimalway to arrest the heart. We briefly review the historical advances and failures of finding alternatives to high potassium, the drawbacks of a prolonged depolarized membrane, altered Ca²⁺ intracellular circuits and heterogeneity in atrial-ventricular K⁺ repolarization during reanimation. Many of these untoward effects may be alleviated by a polarized membrane, and we will discuss the basic science and clinical experience from a number of institutions trialling different alternatives, and our institution with a non-depolarizing adenosine, lidocaine and magnesium (ALM) cardioplegia. The future of polarized arrest is an exciting one and may play an important role in treating the next generation of patients who are older, and sicker with multiple comorbidities and require more complex operations with prolonged cross-clamping times.

Change in Functional Moderate Mitral Regurgitation after Aortic Valve Replacement

Objective

To evaluate the changes of the mitral valve geometrics and the degrees of moderate mitral regurgitation (MR) in patients undergoing aortic valve replacement (AVR) for aortic stenosis (AS).

Methods

A retrospective analysis study of intraoperative transesophageal echocardiography (TEE) and postoperative transthoracic echocardiography (TTE) was performed in 49 patients diagnosed with pure AS combined with moderate MR, who underwent AVR from January 2013 to December 2017. TEE was used to evaluate the direct geometric changes of the mechanical effects on mitral annulus after AVR. TTE was used to evaluate the changes of MR after operation. All patients underwent TTE during the midterm follow-up. The mean follow-up time was 40.21 months.

Results

All of the 49 patients had moderate MR. Anterolateral-posteromedial diameter, anterior-posterior diameter, and mitral annular area were significantly reduced after AVR, while no significant changes were found in the intraoperative left ventricular loading conditions before and after AVR. The degree of mitral valve regurgitation, left ventricular size, left atrial size, left ventricular end-diastolic volume, and left ventricular to aortic pressure gradient were significantly reduced before discharge, and midterm follow-up showed good results.

Conclusion

This study supports the belief that aortic outflow tract obstruction and an actual mechanical compression of the anterior mitral annulus after AVR would cause reduction in MR. Ventricular remodeling would also cause reduction in MR with time going on. Patients with AS, especially young patients with moderate MR, were most likely to benefit from AVR in early time.

Normokalemic nondepolarizing long-acting blood cardioplegia

Objective Blood cardioplegia, the gold-standard cardioprotective strategy, requires frequent dosing, resulting in hyperkalemia-induced myocardial edema. The aim of our study was to compare the efficacy and safety of a long-acting blood-based cardioplegia with physiological potassium levels versus the well-established cold blood St. Thomas' Hospital no. 1 cardioplegia solution in multivalve surgeries. Methods One hundred patients undergoing simultaneous elective aortic and mitral valve replacement ± tricuspid valve repair were randomized in two groups. In group 1, adenosine 12 mg was given via the aortic root after crossclamping, followed by a single dose of long-acting solution at 14℃ (30 mLċkg^-1); in group 2, an initial 30 mLċkg^-1 of St. Thomas' cardioplegia at 14℃ was administered, followed by 15 mLċkg^-1 every 20 min. Duration of cardiopulmonary bypass, inotropic score, arrhythmias, ventilation time, and the levels of interleukin-6, creatinine kinase-MB, and troponin I were compared. Results Mean cardiopulmonary bypass and crossclamp times were 134.04 ± 36.12 vs. 154.34 ± 34.26 ( p = 0.004) and 110.37 ± 24.80 vs. 132.48 ± 31.68 min ( p = 0.002), respectively, in the long-acting and St. Thomas' groups. Cardiac index, creatinine kinase-MB and troponin I levels were comparable. Interleukin-6 levels post-bypass were 61.72 ± 15.33 and 75.44 ± 31.78 pgċmL^-1 ( p = 0.007) in the long-acting and St. Thomas' cardioplegia groups, respectively. Conclusions Single-dose long-acting cardioplegia gives a cardioprotective effect comparable to repeated doses of the well-established St. Thomas' Hospital no. 1 cold blood cardioplegia.