Potassium channel openers: are they effective as pretreatment or additives to cardioplegia?
BACKGROUND
This study was designed to test the hypothesis that the potassium channel opener pinacidil (Pin) as a pretreatment (PT) agent or additive to St. Thomas' solution (StT) could enhance myocardial protection.


METHODS
In a parabiotic rabbit Langendorff model, 36 hearts underwent global normothermic ischemia (1 hour) followed by reperfusion (30 minutes). Cardioplegia (50 mL, every 20 minutes) consisted of: StT; PinPT/StT, where Pin PT preceded StT arrest; Pin alone; Pin in StT (Pin/StT); and Pin in low potassium StT. Systolic function after reperfusion (percent recovery of developed pressure) and compliance (diastolic slope from pressure-volume relationship) were measured.


RESULTS
There was no significant difference between StT and PinPT/StT in percent recovery of developed pressure (51.54% +/- 3.5%, 42.17% +/- 4.0%, respectively) or compliance. Likewise, no significant differences occurred between Pin, StT, Pin/StT, and Pin in low potassium StT in percent recovery of developed pressure (58.99% +/- 4.8%, 51.54% +/- 3.5%, 53.09% +/- 3.2%, 66.43% +/- 7.3%, respectively) or compliance.


CONCLUSIONS
Pin is as effective a cardioplegic agent as StT; however, its use as a pretreatment or additive to traditional and Pin in low potassium StT provided no additional benefit in functional recovery.
Ducko
C T
CT
Department of Surgery, The Milton S. Hershey Medical Center, Penn State Geisinger Health System, Hershey, Pennsylvania, USA.
Stephenson
E R
ER
Jayawant
A M
AM
Vigilance
D W
DW
Damiano
R J
RJ
D000818:Animals; D001639:Bicarbonates / Q000627:therapeutic use; D002122:Calcium Chloride / Q000627:therapeutic use; D002314:Cardioplegic Solutions / Q000627:therapeutic use*; D003326:Coronary Circulation / Q000187:drug effects; D005260:Female; D008274:Magnesium / Q000627:therapeutic use; D008297:Male; D010227:Parabiosis; D020110:Pinacidil / Q000494:pharmacology / Q000627:therapeutic use*; D015221:Potassium Channels / Q000187:drug effects*; D011189:Potassium Chloride / Q000627:therapeutic use; D011817:Rabbits; D015427:Reperfusion Injury / Q000517:prevention & control; D012965:Sodium Chloride / Q000627:therapeutic use
D001639:Bicarbonates; D002314:Cardioplegic Solutions; D015221:Potassium Channels; C041711:St. Thomas' Hospital cardioplegic solution; D012965:Sodium Chloride; D011189:Potassium Chloride; D020110:Pinacidil; D008274:Magnesium; D002122:Calcium Chloride