Results: In both groups, myocardial LV pH

decreased. In Group 1 hearts with only single dose of antegrade cardioplegia, pH decreased to 6.2 ±0.2 as compared to Group 2 hearts with intermittent antegrade cardioplegia where the pH at the end of 6 hours was 6.7 ±0.3. The mean pH difference was 0.55 (p < .005). The RV had a similar pH response to perfusion (p = .02). MR contrast imaging showed no differences in peak perfusion enhancement in the 2 groups, Group 1 = 62%, Group 2 = 40% (p = NS). There was also no difference of the wet/dry weight ratio.

Discussion:Use of intermittent antegrade cardioplegia

as opposed to a single antegrade dose may lead to improved preservation of the donor heart. This may have a favorable effect on the number of potential donors by allowing for longer distance procurement.

Opportunities with improved donor heart preservation

Fewer marginal heartsHLA based donor-recipient matchingHigher transplant success rates

Conclusion:Intermittent antegrade cardioplegia allows

for improved viability and decreased ischemic injury as compared to single dose antegrade cardioplegia.

Introduction: Despite intense effort to increase awareness

of organ donation, a slight decline in the number of suitable donor hearts has occurred in the last 10 years. A major problem in donor heart procurement is the limited time a donor heart remains viable, thus some donor hearts are removed from the donor pool. The global ischemia induces glycolysis cumulating in oxygen radical formation, lactic acidosis and irreversible cellular injury.

Study Goals:Perfusion of the donor heart with

intermittent antegrade cardioplegic solution will raise myocardial pH and improve myocardial perfusion

Methods and Materials:Porcine hearts were flushed with a ribose based cardioplegic solution and stored at 9.2˚C for 6.1 ±0.6 hrs in the Asporto device (Hibernicor, LLC). Control hearts (Group 1, n = 9) did not receive additional perfusion, experimental hearts (Group 2, n = 8) received intermittent antegrade cardioplegia (150 ml, q30 min, 150 ml/min). Khuri pH probes were placed into the LV and RV myocardium for continuous measurement. Following removal from the device, contrast enhanced T-1 weighted MR imaging was performed in the short axis view. Peak contrast enhancement was used as a measurement of viable microvasculature. Wet/dry weight was then measured.

1,3Andrew L. Rivard, 3Cory M. Swingen, 3Forum D. Kamdar, 3Zach Demorest, 3Erin J. Cordova, 3John E. Foker, 2Michael Jerosch-Herold, 3Richard W. Bianco, and 3Ranjit John.

Author Institutions:1University of Florida, 2Oregon Health Sciences Center, and the 3University of Minnesota

Intermittent antegrade cardioplegia: Implications for donor heart preservation

LilleheiHeart

Institute

Financial Disclosure: Dr. Rivard is a member of Hibernicor LLC.

ExperimentalSurgicalServices

Figure 1: The Hibernicor Asporto heart preservation device consists of a lighweight pump, touchscreen microcontroller, and insulated thermo-electric cooler powered by 120 VAC or 12 VDC which maintains a temperature between 4.5 and 10°C.

Figure 2: Intermittent antegrade cardioplegia causes a rise in pH in Group 2 hearts that is more apparent in the LV (blue line) as compared to the RV (red line). The temperature (green line) remained stable at 9˚C.

Figure 3: LV myocardial pH of the Group 1 control hearts (red line) immediately following one liter of antegrade cardioplegic solution. Intermittent antegrade cardioplegia of Group 2 experimental hearts (orange line) maintained a significantly higher pH (p < .005).

Superoxide

Endothelial Relaxing Factor NO●

ATP

Energy

CO2

Oxygen Radicals

-O2 H2O2 + OH●

-NO3

Hydroxy Radical

●NO2 + OH●

Nitrites

Mitochondria

Oxidases

ONOO- + H+

CellularDamage

xanthine oxidase

Xanthine + H2O

H2O

Urate-O●

Ca2+ + Calpain + xanthine dehydrogenase

Oxygen

ONOOH Nitrates

Donor HospitalHeart placed into

device by transplant team

Transplant CenterHeart removed from

device and transplanted in recipient

Organ Procurement Organization

(OPO)

Heart Preservation

Device

Donor HeartTransported to

transplantcenter

Biochemical Pathways of Metabolite Formation

pH

5.5

6.0

6.5

7.0

7.5

16:1

2

17:1

2

18:1

2

19:1

2

20:1

2

21:1

2

22:1

2

23:1

2

0:12

1:12

2:12

3:12

4:12

5:12

6:12

Time

pH

0

2

4

6

8

10

12Tem

p (degree C)

5.9

6.1

6.3

6.5

6.7

6.9

7.1

7.3

7.5

Time (hours)

pH

0 1 2 3 4 5 6

Glucose

Pyruvate

Lactate

ATP Glycolysis