Myocardial distribution of retrograde cardioplegic solution assessed myocardial thallium 201 uptake

Comparison of simultaneous antegrade/vein graft cardioplegia with antegrade cardioplegia for myocardial protection

Antegrade cardioplegic delivery via the aorta ensures distribution of cardioplegic solution through open arteries, but distribution may not be adequate beyond a stenotic coronary artery. This potential problem can be overcome by direct delivery of cardioplegia via a vein graft. The purpose of this study was to compare simultaneous antegrade/vein graft cardioplegia with antegrade cardioplegia during coronary artery bypass surgery. Twenty patients were divided into 2 groups. In group 1, intermittent antegrade cardioplegia was provided (n=10). In group 2, intermittent antegrade cardioplegia was supplemented by antegrade perfusion of vein grafts after distal anastomoses were completed (n=10). Data on enzyme release and hemodynamics were obtained preoperatively, before the induction of anesthesia, just before cross-clamping, immediately after aortic unclamping, and at 1, 6, 12, 24, and 48 h after unclamping. Enzyme release (creatinine phosphokinase-isoenzyme MB, cardiac troponin I, myoglobin) was similar in both groups (P>.05). Furthermore, no significant difference was noted in the incidence of postoperative low cardiac output syndrome, perioperative myocardial infarction, or ventricular arrhythmia (P>.05). In conclusion, both techniques permitted rapid postoperative recovery of myocardial function. Supplementation of antegrade perfusion of vein grafts with antegrade cold blood cardioplegia offered no advantage to study patients.However, hemostasis of a distal anastomosis may be controlled by this technique.

Retrograde crystalloid cardioplegia preserves left ventricular systolic function better than antegrade cardioplegia in patients with occluded coronary arteries

OBJECTIVE

To investigate retrograde and antegrade crystalloid cardioplegia in terms of cardiac cooling and postoperative cardiac function.

DESIGN

Prospective, randomized, and blinded.

SETTING

University hospital.

PARTICIPANTS

Twenty male patients with triple-vessel disease and proximal occlusion of the circumflex or the left anterior descending coronary artery.

INTERVENTIONS

Left ventricular ejection fraction at rest and during exercise was evaluated by nuclear ventriculography the day before and 3 months after surgery. After induction of anesthesia and hourly for the first 5 postoperative hours, hemodynamic, echocardiographic, and electrocardiographic data were acquired. Myocardial temperature was measured with needle thermistors in 3 myocardial regions.

MEASUREMENTS AND MAIN RESULTS

Demographic and temperature data were analyzed by t-test. Hemodynamic and echocardiographic data were analyzed by analysis of variance. The groups were similar in baseline characteristics. Retrograde cardioplegia cooled the region distal to an occlusion better than antegrade cardioplegia (9.6 degrees C +/- 4.8 degrees C v 21.8 degrees C +/- 5.9 degrees C; p < 0.01). Hemodynamic, echocardiographic, and electrocardiographic data did not differ between the groups. Three months after surgery, the retrograde cardioplegia group showed a higher left ventricular ejection fraction at rest (58% +/- 10% v 47% +/- 10%; p < 0.02) and during exercise (58% +/- 13% v 47% +/- 10%; p < 0.05) compared with the antegrade cardioplegia group.

CONCLUSIONS

Retrograde cardioplegia provides more homogenous myocardial cooling than antegrade cardioplegia in hearts with coronary artery occlusions. The use of retrograde cardioplegia seems to benefit long-term left ventricular function.

Simultaneous antegrade and retrograde delivery of continuous warm blood cardioplegia after global ischemia

OBJECTIVE

Simultaneous delivery of antegrade and retrograde cardioplegia may provide a more homogeneous distribution of cardioplegic solution. It may, however, increase myocardial edema and postcardioplegic myocardial injury. The purpose of this study was to compare simultaneous antegrade-retrograde cardioplegia with antegrade cardioplegia.

METHODS

After 30 minutes of warm, "unprotected," global ischemia, pigs were given warm, continuous blood cardioplegia for 45 minutes (antegrade group, n = 8 and simultaneous antegrade-retrograde group, n = 9). All pigs were weaned from cardiopulmonary bypass 45 to 60 minutes after aortic unclamping. Indices of left ventricular function were measured after another 30 minutes with the conductance catheter technique and pressure-volume loops.

RESULTS

Global left ventricular function, evaluated by preload recruitable stroke work, decreased from baseline values of 126 (102 to 150) (mean [90% confidence limits]) (antegrade) and 122 (116 to 127) erg/ml x 10(3) (simultaneous) to 75 (61 to 89) (p = 0.004) and 95 (79 to 112) erg/ml x 10(3) (p = 0.02), respectively. End-diastolic pressure-volume relation increased from 0.25 (0.21 to 0.28) (antegrade) and 0.30 (0.25 to 0.35) mm Hg/ml (simultaneous) to 0.60 (0.41 to 0.79) (p = 0.009) and 0.53 (0.35 to 0.71) mm Hg/ml (p = 0.02), respectively. The time constant of left ventricular pressure relaxation was unchanged. No intergroup difference was observed in preload recruitable stroke work, preload recruitable stroke work area, end-diastolic pressure volume relation, or stiffness constant. Plasma levels of troponin T increased without any difference between groups. Myocardial water content was increased in the simultaneous group (81.1% [80.7% to 81.5%]) versus the antegrade group (80.1% [79.6% to 80.7%], p = 0.01).

CONCLUSION

Despite a small increase in myocardial water content induced by simultaneous blood cardioplegia, no impairment of postcardioplegic cardiac function was observed compared with antegrade cardioplegia.

Does retrograde administration of blood cardioplegia improve myocardial protection during first operation for coronary artery bypass grafting?

BACKGROUND

The objective of this study was to evaluate the value of retrograde blood cardioplegia in coronary artery bypass grafting.

METHODS

In 1994 and 1995, 224 patients undergoing first-time isolated coronary artery bypass grafting were randomized to antegrade (112 patients, group 1) or retrograde (112 patients, group 2) administration of blood cardioplegia. In group 1, 76 patients were given warm cardioplegia (at 33 degrees C) and 36 had cold cardioplegia (< 20 degrees C), whereas in group 2 cardioplegia was warm in 77 patients and cold in 35. The two randomization groups had similar demographic and angiographic characteristics. The number of grafted coronary arteries averaged 2.9 +/- 0.7 in group 1 and 2.8 +/- 0.7 in group 2. Total duration of cardiopulmonary bypass (78 +/- 23 and 75 +/- 21 minutes) and of aortic cross-clamping (47 +/- 16 and 46 +/- 16 minutes), total volume of infusion of the crystalloid component of cardioplegia (988 +/- 297 and 1016 +/- 595 mL), and total duration of infusion of cardioplegia (23 +/- 10 and 22 +/- 11 minutes) were similar (p > 0.05).

RESULTS

There was no death in group 1 and one in group 2 as a result of a pulmonary embolus, for a global early mortality of 0.45%. The numbers of perioperative myocardial infarction (5 versus 3), congestive heart failure (4 versus 5), postoperative hemorrhage (4 versus 4), and stroke (1 versus 2) were also similar (p > 0.05). Release curves of total creatine kinase, creatine kinase-MB by serum activity and mass concentration, and troponin T were not significantly different (p > 0.05) between the two groups. For the 216 patients without perioperative myocardial infarction, peak enzyme release of creatine kinase-MB at 24 hours averaged 23 +/- 22 and 20 +/- 18 IU/L, and that of troponin T averaged 1.1 +/- 1.1 and 1.3 +/- 1.5 micrograms/L at 6 hours for the antegrade and the retrograde groups, respectively (p > 0.05).

CONCLUSIONS

Our results indicate no evidence that the retrograde method of cardioplegic infusion improves myocardial protection during first operation for isolated coronary revascularization compared with the usual antegrade route.

Clinical trial of retrograde warm blood reperfusion versus standard cold topical irrigation of transplanted hearts

BACKGROUND

A prospective, randomized clinical study involving 34 patients undergoing heart transplantation compared myocardial preservation of donor hearts maintained with continuous reperfusion with retrograde warm blood cardioplegia during surgical implantation versus the standard cold topical irrigation.

METHODS

Hearts in both groups were arrested with a standard crystalloid solution and maintained in a cold saline solution during transportation. In the retrograde group, cardioplegia was administered through a catheter in the coronary sinus during surgical implantation. An average of 471 +/- 30 mL of hyperkalemic crystalloid solution diluted 1:4 in warm blood from the oxygenator was infused. In the standard group, the heart was kept cold by topical irrigation of cold saline solution and was reperfused only when the ascending aorta was unclamped.

RESULTS

Preoperative characteristics of donors and recipients were similar in the two cohorts. Ischemic time average 139 +/- 12 minutes in the retrograde group compared with 130 +/- 11 minutes in the standard group (p = 0.57). Cardiopulmonary bypass time averaged 89 +/- 4 minutes in the retrograde group and 110 +/- 12 minutes in the standard group (p = 0.12). Defibrillation at reperfusion was performed in 4 patients (4/17, 24%) in the retrograde group and 12 patients (12/18, 67%) in the standard group (p = 0.01). There were no deaths in the retrograde group (0/17), whereas in the standard group, 3 patients (3/17) died of early graft failure (p = 0.11). Four early graft failures occurred in the standard group (p = 0.06). Two patients (2/17, 12%) were weaned from bypass with ventricular assist devices in the standard group. The number of subendocardial necrotic cells in the first two weekly endomyocardial biopsy specimens averaged 2.7 +/- 0.8 cells/mm2 in the retrograde group and 5.9 +/- 2.4 cells/mm2 in the standard group (p = 0.12).

CONCLUSIONS

Retrograde warm blood reperfusion appears to improve the initial recovery of transplanted hearts. The technique is easy to use and may be a useful approach to graft protection during surgical implantation.

Evidence that continuous normothermic blood cardioplegia offers better myocardial protection than intermittent hypothermic cardioplegia

OBJECTIVES

To compare transmyocardial ischaemia and oxidative stress, as well as non-infarction myocardial injury, in patients randomised to intermittent hypothermic cardioplegia or continuous normothermic blood-potassium cardioplegia.

DESIGN

Prospective randomised trial.

SETTING

Tertiary cardiac referral centre.

METHODS

24 patients undergoing elective coronary artery bypass surgery were randomised to hypothermic (13 patients, mean (SEM) age 59.5 (2.6) years) or normothermic (11 patients, mean (SEM) age 59.7 (3.3) years) cardioplegia. Transmyocardial oxidative stress and ischaemia were assessed by the difference in plasma concentrations of oxidised glutathione and lactate respectively, from samples taken simultaneously from the coronary sinus and aortic root. Blood samples were taken just before cross clamp application and at intervals up to 15 min after cross clamp release. Non-infarction myocardial injury was assessed by measurement of creatine kinase MB isoenzyme activity from peripheral venous blood taken 2 and 18 h after surgery.

RESULTS

Intermittent hypothermic cardioplegia resulted in a significant increase in transmyocardial ischaemia (P < 0.001) and oxidative stress (P < 0.001). Evidence of significantly increased myocyte damage was also present (P < 0.01). No significant corresponding changes were present with normothermic cardioplegia.

CONCLUSIONS

Normothermic blood cardioplegia seems to avoid significant changes in myocardial ischaemic status and consequent oxidative stress. This study provides direct evidence that normothermic cardioplegia offers enhanced myocardial protection compared with that of hypothermic cardioplegia. Certain subsets of patients may derive more benefit from normothermic cardioplegia, although it is unclear whether this would be the case for all patients.