T . Takeichi et al .: J Extra Corpor Technol 2024 , 56 , 207 – 210 209
Figure 3 . ( a ) Showing did not get a good vision because of aortic regurgitation after de-clamping ACC . ( b ) After circulatory arrest combined with systemic hyperkalemia without ACC we could get a good view . ACC : Aortic cross-clamping .
rendering the procedure too challenging . Consequently , systemic hyperkalemia without ACC was employed . To ensure adequate cardioplegia delivery , thorough adhesiolysis was imperative to avoid damaging the SVG , with direct retrograde cardioplegia potentially being insufficient .
After de-clamping , a mixed solution ( 500 mL of bicarbonate ringer solution with 50 mL of KCL 10 mEq / L , 20 mL of MgSO 4 , and 100 mg of 2 % lidocaine ) was continuously infused from CPB to maintain cardiac arrest , targeting a blood potassium level of 9.0 mEq / L . Due to the influence of aortic regurgitation , maintaining a clear surgical field was challenging ; hence , MVR was performed in conjunction with circulatory arrest ( Figures 3a and 3b ). Bladder and eardrum temperatures were recorded at 26.0 ° C and 23.0 ° C , respectively . MVR was executed with intermittent circulatory arrest periods of 3 – 5 min during annulus suturing and prosthetic valve sizing , totaling 39 min of circulatory arrest . Upon confirming a vent through the mitral valve in the left ventricle , continuous mixed solution infusion ceased , maintaining cardiac arrest until the left atrium was closed . In the event of heartbeats , 100 mg of 2 % lidocaine was infused to re-induce cardiac arrest by inhibiting voltage-dependent Na + channels .
Following the closure of the left atrium , rewarming commenced alongside potassium level reduction and GHDF initiation . At that juncture , potassium concentration was 8.5 mEq / L . The combination of continuous furosemide and GHDF effectively reduced potassium levels instantaneously . CPB was weaned using 3.1c of dobutamine and 0.03c of noradrenaline . The rewarming duration was 40 minutes , and the time to normalize potassium levels to 5.0 mEq / L was 30 min , using 14000 mL of saline solution in the GHDF dialysate . Cardiac arrest duration was 189 min , and CPB time was 325 minutes , with a post-CPB potassium level of 4.8 mEq / L and a peak level of 10.5 mEq / L . Urine output during CPB was 6.5 mL / kg / h . The patient ’ s postoperative peak creatine-kinase MB ( CK-MB ) level was 24.0 ng / dL , and the peak creatinine value was 2.83 mg / dL . Mechanical ventilation duration was 15 h , and ICU stay was 8 days . No major complications , including acute kidney injury , were noted . The postoperative course was uneventful , and the patient was discharged .
Informed consent to report patient information and images was obtained .
Discussion
Reoperative valve surgery is recognized for its complexity , increased morbidity , and elevated mortality rates , with the challenges in cardioplegia administration significantly affecting patient outcomes [ 4 , 5 ]. In this case of incomplete ACC , we safely executed a high-risk redo MICS MVR under systemic hyperkalemia combined with circulatory arrest , bypassing the need for ACC . Our prior experience with systemic hyperkalemia during CPB enabled us to promptly address the incomplete ACC scenario utilizing systemic hyperkalemia without ACC [ 3 ].
When faced with severe adhesion of the IVC and SVG traversing the right atrium , retrograde cardioplegia poses significant difficulty . In cases where cross-clamping is challenging , techniques such as the BH method or VF arrest can be safely employed [ 2 – 4 , 6 ]. However , some researchers have demonstrated that the VF approach is inferior to the BH technique due to its reduced oxygen delivery to the sub-endocardium , leading to suboptimal myocardial protection . Sub-endocardial perfusion occurs during diastole , and the compressive forces of fibrillation impede myocardial blood flow and oxygen delivery during the diastolic phase of VF [ 2 , 7 ]. Hiraoka et al . reported that intraoperative myocardial protection under mild hypothermia and VF is not inferior to protection achieved with cardioplegic arrest [ 8 ].
These strategies are effective provided that aortic insufficiency is no more than mild to moderate . Severe aortic insufficiency complicates the maintenance of a bloodless surgical field and can lead to coronary malperfusion [ 7 , 9 ]. In this case , mild aortic regurgitation was identified via preoperative TEE . Due to the regurgitation , achieving a clear surgical field without circulatory arrest was unfeasible . In such scenarios , combining circulatory arrest with systemic hyperkalemia CPB can be beneficial , as it ensures uniform myocardial protection compared to fibrillatory arrest . Postoperative creatine kinase-MB ( CK-MB ) levels were 24 ng / dL , and there are no previous reports of systemic hyperkalemia combined with circulatory arrest without ACC .
Opinions on this approach may vary . In high-risk cases , some surgeons might prefer median sternotomy over MICS to avoid cardioplegia-related complications . However , we posit