In Search Of Optimal Cardioplegia: Diminished Delivery Dose Of Long Acting Solutions Resulting In Less Hemodilution
Serdar Gunaydin, Seyhan Babaroglu, Erdal Simsek, Okay Guven Karaca.
University of Health Sciences, Ankara, Turkey.
BACKGROUND: Despite promising results regarding the use of single-dose cardioplegia in minimally invasive surgery, there are still concerns regarding the impact of hemodilution hindering the clinical advantages of this surgical technique. This study aims to document the safety and feasibility of 1000 mL single dose delivery of del Nido cardioplegia (DNC) and histidine-tryptophan-ketoglutarate (HTK) solution with a target of 60 min ischemic time in minimally invasive aortic valve replacement (m-AVR).METHODS:Following ethics approval, during a one-year period, 87 patients undergoing mAVR with an expectation of cross-clamp time< 60 min were prospectively randomized to receive DNC (N=46) or HTK (N=41), 4-8°C, 1000 mL in 5 min via 80-100 mmHg pressure (up to 60 min ischemic time). Inclusion criteria were patients aged 50-79 years, providing informed consent, scheduled for mAVR with x-clamp time expected to be <60 min. Exclusion criteria were hemodynamic instability, renal failure, previous cardiac surgery, conversion to sternotomy and neurological dysfunction. Patients needing earlier and additional dosing were excluded. Redosing was done with half dose of the initial regimen. No ultrafiltration was used. Blood samples were collected at the following time intervals: after induction of anesthesia before CPB (T1), after cessation of CPB (T2), ICU on the first postoperative day at 8 am (T3). Primary endpoints were the hematocrit levels at T2 and the perioperative rate of blood products transfusion.
RESULTS: In two patients from DNC and one in HTK, there was a need for conversion to full sternotomy; three patients in the DNC and one in the HTK group needed earlier redosing (<60 minutes; heart started beating/fibrillation); five patients in DNC and two in HTK received redosing and were all excluded. The feasibility of 60-min ischemic time was 82% for DNC and 93% for HTK. Perioperative outcome is summarized in Table.
CONCLUSIONS: Diminished dose (one-liter) of single-dose cardioplegic solutions provided safe and acceptable myocardial protection in 82/93% of patient population within 60-min ischemic time. Potential concerns of full dosing represented by hemodilution, increased transfusion, need for ultrafiltration, sodium imbalance and arrhythmia were overruled. Further studies with larger patient population are warranted.
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