Warm Antegrade Research Articles

Rescue of a case of ventricular septal defect with Eisenmenger syndrome using an extracorporeal membrane oxygenator

Clinical Summary A 38-year-old male patient presented with severe respiratory distress. A large VSD with Eisenmenger syndrome had been diagnosed in the patient 2 years previously (Figure 1). A chest x-ray film revealed a pulmonary hemorrhage at the upper lobe of the right lung (Figure 2, A). The patient’s arterial oxygen concentration was extremely low (68%) even with ventilator support of 100% oxygen. A venovenous extracorporeal membrane oxygenator (ECMO) was inserted through the left femoral vein (outflow from the patient) and right jugular vein (inflow to the patient) in an attempt to increase his oxygen saturation. Because of severe mixing of blood across the VSD, the percutaneous saturation was still low (SpO2 74%) even with the venovenous ECMO support. Intermittent bradycardia occurred during the support, which was considered to be the result of inadequate tissue oxygenation. It seemed critical to find a way to decrease the mixing of deoxygenated blood across the VSD to save the patient’s life. Two days later, after a discussion with the patient’s family, we decided to perform an operation to close the VSD and create an atrial septal defect (ASD) with the use of cardiopulmonary bypass and aortic crossclamping. To prevent right-sided heart failure after the open operation, myocardial temperature was kept at 37°C with warm antegrade and retrograde cardioplegic solution. The large perimembranous VSD without aortic overriding was closed with a knitted Dacron patch and continuous suture with 4-0 polypropylene. A 1.5 1.5 cm fenestration at the atrial level was created to prevent congestion of the right side of the heart after closure of this large VSD. The operation was completed smoothly without right-sided heart failure developing. The patient was sent back to the intensive care unit with

Paraganglioma of the left atrium

J Thorac Cardiovasc Surg 2001;122:1032-3

Does Warm Antegrade Intermittent Blood Cardioplegia Really Protect the Heart during Coronary Surgery?

Objective: Intermittent antegrade blood cardioplegia (IABC) has been standardized as a routine technique for myocardial protection in coronary surgery. However, if the myocardium is known to tolerate short periods of ischemia during hypothermic arrest, it may be less tolerant of warm ischemia, so the optimal cardioplegic temperature of intermittent antegrade blood cardioplegia is still controversial. The aim of this study was to compare the effects of warm intermittent antegrade blood cardioplegia and cold intermittent antegrade blood cardioplegia on myocardial pH and different parameters of the myocardial metabolism. Methods: Thirty patients undergoing first-time isolated coronary surgery were randomly allocated into two groups: group 1 (15 patients) received warm (37°C) intermittent antegrade blood cardioplegia and group 2 (15 patients) received cold (4°C) intermittent antegrade blood cardioplegia. The two randomization groups had similar demographic and angiographic characteristics. Total duration of cardiopulmonary bypass (108 ± 17 and 98 ± 21 min) and of aortic cross-clamping (70 ± 13 and 65 ± 15 min) were similar. The cardioplegic solutions were prepared by mixing blood with potassium and infused at a flow rate of 250 ml/min for a concentration of 20 mEq/l during 2 min after each anastomosis or after 15 min of ischemia. Intramyocardial pH was continuously measured during cardioplegic arrest by a miniature glass electrode and values were corrected by temperature. Myocardial metabolism was assessed before aortic clamping ( pre-XCL), 1 min after removal of the clamp ( XCL off) and 15 min after reperfusion (Rep) by collecting coronary sinus blood samples. All samples were analyzed for lactate, creatine kinase (MB fraction), myoglobin and troponin I. Creatine kinase and troponin I were also daily evaluated in peripheral blood during 6 days post-operatively. Results: The clinical outcomes and the haemodynamic parameters between the two groups were identical. In group 1, XCL off and Rep were associated with higher coronary sinus release of lactate (5.5 ± 1.8 and 2.2 ± 0.5 mmol/l) than in group 2 (2.0 ± 0.7 and 1.6 ± 0.3 mmol/l, P < 0.05). Mean intramyocardial pH was lower in group 1 (7.23 ± 0.08) than in group 2 (7.65 ± 0.30, P < 0.05). There were no significant differences between the two groups with respect of creatine kinase (MB fraction) either after Rep or during the post-operative period. Lower coronary sinus release of myoglobin was detected at Rep in group 1 (170 ± 53 μg/l) than in group 2 (240 ± 95 μg/1, P < 0.05). At day 1. a lower release of troponin I was found in group 1 (0.11 ± 0.07 g/ml) compared to group 2 (0.17 ± 0.07ng/ml. P < 0.05). Conclusion: With regards to similar clinical and haemodynamic results, myocardial protection induced by warm IAEX is associated with more acidic conditions (intramyocardial pH and lactate release) and less myocardial injury (myoglobin and troponin I release) than cold intermittent antegrade blood cardioplegia during coronary surgery.

Myocardial perfusion during warm antegrade and retrograde cardioplegia: a contrast echo study

Background. We evaluated distribution of warm antegrade and retrograde cardioplegia in patients undergoing coronary artery bypass grafting (CABG). Methods. Myocardial perfusion was evaluated pre- and post-CABG using transesophageal echocardiography with injection of sonicated albumin microbubbles (Albunex) during warm antegrade and retrograde cardioplegia. The left ventricle (LV) was evaluated in five segments and the right ventricle (RV) was evaluated in two segments. Segmental contrast enhancement was graded as absent (score = 0), suboptimal or weak (score = 1), optimal or excellent (score = 2), or excessive (score = 3). Results. Pre-CABG cardioplegic perfusion correlated weakly with severity of coronary artery stenoses ( r = −0.331 and 0.276 for antegrade and retrograde cardioplegia, respectively). Antegrade cardioplegia administration resulted in 98% and 96% perfusion to the left ventricle pre- and post-CABG, respectively. Retrograde cardioplegic administration resulted in reduced LV perfusion, with 86% ( p = 0.032 from antegrade) and 59% ( p < 0.001 from antegrade) pre- and post-CABG, respectively. The average LV perfusion score (mean ± SEM) was greater with antegrade than retrograde cardioplegia both pre-CABG (1.93 ± 0.04 vs 1.53 ± 0.11, p < 0.001) and post-CABG (1.63 ± 0.07 vs 1.19 ± 0.13, p = 0.004). RV perfusion was poor with both techniques pre-CABG, but improved significantly with antegrade cardioplegia post-CABG. Conclusions. We conclude that warm antegrade cardioplegia results in better left ventricular perfusion than warm retrograde cardioplegia. Right ventricular cardioplegic perfusion was suboptimal, but the best delivery was achieved with antegrade cardioplegia after coronary bypass. We therefore recommend construction of the saphenous vein graft to the right coronary artery early in the operative procedure.

Adequate distribution of warm cardioplegic solution

Seventy-five patients undergoing coronary artery bypass grafting were randomized to receive warm antegrade ( N = 25), warm retrograde ( N = 25), or a combination of warm antegrade and retrograde ( N = 25) delivery of blood cardioplegic solution. Myocardial oxygen utilization, lactate and acid metabolism, and adenine nucleotides and their degradation products were measured during the operation and cardiac function was assessed postoperatively. Warm retrograde delivery of cardioplegic solution increased lactate and acid release during cardioplegia and reperfusion, decreased left ventricular adenosine triphosphate concentrations, and reduced the washout of adenine nucleotide degradation products from both left and right ventricles. Warm antegrade delivery of cardioplegic solution resulted in less lactate and acid release during cardioplegia but more lactate accumulated in the territory of the left anterior descending artery during the crossclamp period. Intermittent antegrade delivery of the cardioplegic solution during combination cardioplegia washed out lactate and acid, which suggested inhomogeneous delivery of the cardioplegic solution during continuous retrograde cardioplegia. Combination cardioplegia best preserved adenosine triphosphate in the left ventricle and resulted in the best postoperative left and right ventricular function. A combination of intermittent antegrade and continuous retrograde delivery of cardioplegic solution provided better myocardial protection than either antegrade or retrograde delivery of cardioplegic solution alone. (J T HORAC C ARDIOVASC S URG 1995;110: 800-12)

Neurological Outcomes and Cardiopulmonary Temperature: A Clinical Review

All available controlled studies of warm versus cold and antegrade versus retrograde delivery of cardioplegia were reviewed to assess the incidence of perioperative stroke and adverse neuropsychological outcomes. Nine randomized trials and substudies and two studies with immediate historical consecutive controls reported neurological outcomes and were described as warm versus cold. Pooled event rates for perioperative stroke were 1.5% for warm antegrade, 3.14% for warm retrograde, 1.7% for cold antegrade, and 0% to 1.2% for cold retrograde. Examining within trial differences, only one study showed a significant disadvantage to warm 4.5% versus cold 1.4% on incidence of perioperative stroke, but the design does not permit determination of whether the difference is due to systemic temperature, retrograde coronary perfusion, or other factors. Furthermore, if only warm (> 33 degrees C) versus cold (< 30 degrees C) systemic perfusion is examined in all studies for the incidence of stroke irrespective of cardioplegia temperature or antegrade versus retrograde coronary perfusion (warm 2.1%; cold 1.6%), the above study remains a significant outlier. This suggests that the differences found are unlikely to be due to temperature but may be related to antegrade versus retrograde coronary perfusion. Review of randomized trials evaluating neuropsychological function post-cardiopulmonary bypass (post-CPB) also failed to reveal any advantage related to temperature of systemic perfusion. Since manipulations that are most likely to give rise to cerebral embolization are uniformly carried out at normothermia at the beginning and end of the operation, it is not entirely unexpected that the incidence of neurological events was found to be independent of the temperature of CPB.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral microemboli during coronary artery bypass using different cardioplegia techniques

Larger numbers of microemboli detected by transcranial Doppler echocardiography have been linked to adverse neuropsychological outcome after coronary artery bypass grafting. Differences in neurologic outcome have been attributed to different cardioplegia techniques. Transcranial Doppler-detected microembolic events were recorded during coronary artery bypass grafting using different cardioplegia techniques. Patients received cold antegrade (n = 20), warm antegrade (n = 17), or warm retrograde (n = 20) cardioplegia. Continuous monitoring was divided into stages: aortic cannulation, initiation of cardiopulmonary bypass, aortic cross-clamping, aortic declamping and decannulation until chest closure. Rate of embolic events and number of total and immediate embolic events were tabulated. Total embolic events ranged from 22 to 2,072 per patient and were similar among groups. The rate and total at each stage were similar. Total embolic events were highest during aortic clamping; the rate was highest at initiation of bypass. The immediate embolic events were higher in the warm retrograde group than both antegrade groups at aortic declamping. In summary, a high total and rate of embolic events were detected and differences between cardioplegia techniques were detected.

The optimal cardioplegic temperature

Seventy-two patients undergoing coronary artery bypass grafting were randomized to receive cold (8 °C) antegrade or retrograde, tepid (29 °C) antegrade or retrograde, or warm (37 °C) antegrade or retrograde blood cardioplegia (n = 12 in each group). Myocardial oxygen utilization as well as lactate and acid metabolism were assessed intra-operatively and cardiac function was assessed postoperatively. Myocardial oxygen consumption and anaerobic lactate release were greatest during warm, intermediate during tepid, and least during cold cardioplegic arrest. Myocardial oxygen consumption and lactate release were underestimated during retrograde cardioplegia because of contamination of aortic root samples. Warm retrograde and tepid retrograde cardioplegia resulted in greater lactate and acid washout with reperfusion. Left ventricular stroke work indices were greater after warm antegrade and tepid antegrade cardioplegia than after cold antegrade cardioplegia, and right ventricular stroke work indices were greatest after warm antegrade cardioplegia. Warm antegrade cardioplegia increased aerobic metabolism during and after cardioplegia and preserved left and right ventricular function. Tepid antegrade cardioplegia reduced anaerobic lactate and acid release during arrest and preserved cardiac function.

Which techniques of cardioplegia prevent ischemia?

One hundred seven patients undergoing coronary artery bypass grafting were randomized to receive warm antegrade (n = 21), warm retrograde (n = 22), cold antegrade (n = 20), cold retrograde (n = 22), or intermittent cold antegrade (n = 22) blood cardioplegia. Myocardial oxygen consumption and lactate production, adenine nucleotides, and adenine nucleotide degradation products were measured during the operation, and creatine kinase-MB release was assessed postoperatively. Warm cardioplegia resulted in greater myocardial lactate production than cold cardioplegia ( p = 0.048). Retrograde cardioplegia was associated with greater lactate production than antegrade caidioplegia ( p = 0.015). Adenosine triphosphate depletion was similar among groups. However, poorly diffusible metabolites of adenosine triphosphate accumulated to the greatest extent in the intermittent cold group. Levels of hypoxanthine were highest after warm retrograde cardioplegia. Operative mortality and morbidity were low and were not different among groups. In summary, none of the five techniques of cardioplegia evaluated in this study was able to completely prevent myocardial ischemia. Anaerobic lactate production was minimized with cold cardioplegia and with antegrade cardioplegic delivery. Hypothermia may have impaired regeneration of adenosine triphosphate, however, particularly in association with inadequate or intermittent cardioplegic flow.

Warm heart surgery in patients with cold autoimmune disorders

Continuous warm antegrade delivery of cardioplegia while maintaining systemic normothermia is a new method of performing coronary artery bypass grafting. It can be used to avoid the detrimental effects of hypothermia in patients with cold autoimmune disease.