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

Cardio-Protective Effects of Multiport Antegrade Cold Blood Cardioplegia Versus Antegrade Cold Blood Cardioplegia in Patients With Left Ventricular Systolic Dysfunction Undergoing Conventional Coronary Artery Bypass Grafting

Introduction

The aim of this study was to compare the in-hospital outcomes of multiport antegrade cold blood cardioplegia through vein grafts versus conventional antegrade cold blood cardioplegia in patients with left ventricle systolic dysfunction who underwent coronary artery bypass grafting (CABG).

Methods

This prospective, randomized clinical study was comprised of patients undergoing on-pump CABG at the Ch. Pervaiz Elahi Institute of Cardiology in Multan, Pakistan from November 18, 2018 to December 17, 2019. Patients with multivessel coronary artery disease and left ventricular systolic dysfunction (ejection fraction < 50%) were included. In Group A (N = 73), multiport antegrade cold blood vein graft cardioplegia was given after every distal anastomosis completed for myocardial preservation. In Group B (N = 73), conventional antegrade cold blood cardioplegia was given for myocardial preservation.

Results

Spontaneous rhythm (without defibrillation applied) after cross-clamp removal was higher in Group A than in Group B (93.3% vs. 85.2%, p < 0.05). Duration of support, ventilation time, and hospital stay were also significantly lower in Group A than in Group B with p = 0.00001, p = 0.03, and p = 0.002, respectively. Intra-aortic balloon pump insertion (4.1% vs. 23.0%, p = 0.02) and operative mortality (0.5% vs. 4.0%, p = 0.35) were also lower in Group A than in Group B. Postoperative left ventricular ejection fraction (LVEF) increased more in Group A than in Group B, and the postoperative LVEF mean value was 44.68% in Group A versus 41.26% in Group B (p = 0.02).

Conclusion

Multiport vein graft blood cardioplegia provides superior myocardial protection in patients with left ventricular systolic dysfunction who underwent CABG. It is also easy to administer, so this technique can be adopted as a routine method for myocardial protection in patients with left ventricular dysfunction planned for on-pump CABG.

Myocardial protection in cardiac surgery: how limited are the options? A comprehensive literature review

For patients undergoing cardiopulmonary bypass, myocardial protection is a key for successful recovery and improved outcomes following cardiac surgery that requires cardiac arrest. Different solutions, components and modes of delivery have evolved over the last few decades to optimise myocardial protection. These include cold and warm and blood and crystalloid solution through antegrade, retrograde or combined cardioplegia delivery approach. However, each method has its own advantages and disadvantages, posing a challenge to establish a gold-standard cardioplegic solution with an optimised mode of delivery for enhanced myocardial protection during cardiac surgery. The aim of this review is to provide a brief history of the development of cardioplegia, explain the electrophysiological concepts behind myocardial protection in cardioplegia, analyse the current literature and summarise existing evidence that warrants the use of varying cardioplegic techniques. We provide a comprehensive and comparative overview of the effectiveness of each technique in achieving optimal cardioprotection and propose novel techniques for optimising myocardial protection in the future.

Myocardial Protection in Mitral Valve Surgery: Comparison Between Minimally Invasive Approach and Standard Sternotomy

OBJECTIVE

To compare antegrade and retrograde cardioplegia administration in minimally invasive mitral valve surgery (MIMS) and open mitral valve surgery (OMS) for myocardial protection.

DESIGN

Retrospective study.

SETTING

Tertiary care university hospital.

PARTICIPANTS

The study comprised 118 patients undergoing MIMS and 118 patients undergoing OMS.

INTERVENTIONS

The data of patients admitted for MIMS from 2006 to 2010 were reviewed. Patients undergoing isolated elective OMS from 2004 to 2006 were used as a control group. Cardioplegia in the MIMS group was delivered via the distal port of the endoaortic clamp and an endovascular coronary sinus catheter positioned using echographic and fluoroscopic guidance. Antegrade and retrograde cardioplegia were used in OMS. Data regarding myocardial infarction (MI) (creatine kinase [CK]-MB, troponin T, electrocardiography); myocardial function; and hemodynamic stability were collected.

MEASUREMENTS AND MAIN RESULTS

There was no difference in the perioperative MI incidence between both groups (1 in each group, p = 0.96). No statistically significant difference was found for maximal CK-MB (35.9 µg/L [25.1-50.1] v 37.9 µg/L [28.6-50.9]; p = 0.31) or the number of patients with CK-MB levels >50 µg/L (29 v 33; p = 0.55) or CK-MB >100 µg/L (3 v 4; p = 0.70) between the OMS and MIMS groups. However, maximum troponin T levels in the MIMS group were significantly lower (0.47 µg/L [0.32-0.79] v 0.65 µg/L [0.45-0.94]; p = 0.0007). No difference in the incidence of difficult weaning from bypass and intra-aortic balloon pump use between the MIMS and OMS groups was found.

CONCLUSIONS

Antegrade and retrograde cardioplegia administration during MIMS and OMS provided comparable myocardial protection.

Temperature Management During Cardiopulmonary Bypass: Effect of Rewarming Rate on Cognitive Dysfunction

Hypothermia is a very strong neuroprotective agent during cerebral ischemia. However, several randomized clinical trials have failed to demonstrate a protective effect of hypothermic cardiopulmonary bypass on postoperative cognitive deficits. The lack of neuroprotection may be due to rapid rewarming, which in turn may result in cerebral hyperthermia. The purpose of this study was to detennine if rapid rewarming at the end of cardiopulmonary bypass is associated with an increased risk of postoperative neuropsychologic impairment.

Methods: A battery of neuropsychologic tests were administered preand postoperatively to patients undergoing elective coronary bypass surgery. Patients were allowed to drift to 34°C then rewarmed to 37.5°C at the end of cardiopulmonary bypass. Patients were divided into 2 groups according to the median time to rewarm (21 minutes): a rapid group (n = 70) and a slow group (n = 76).

Results: The 2 groups of patients were similar for all pre-, intra-, and postoperative variables, with the exception of rewarming times (15 ± 4 minutes [mean ± SD]) in the rapid group versus 30 ± 9 minutes in the slow group, p < 0.001). The rapid group had a significantly higher prevalence of neuropsychologic impairment 1 week postoperatively than the slow group (82% versus 57%, p < 0.05), as well as worse mean scores on all neuropsychologic tests. There was a nonsignificant trend toward increased neuropsychologic impairment 3 months postoperatively in the rapid group, as well as worse mean scores on 8 of the 10 tests.

Conclusions: Rapid rewarming at the end of cardiopulmonary bypass may increase the risk of postoperative cognitive impairment. Until further studies are performed, rapid rewarming should be avoided in order to minimize the risk of cerebral hyperthermia.

Laser fluorescence angiography reveals perfusion defects in retrograde cardioplegia

BACKGROUND

Adequate perfusion of the right ventricle with retrograde cardioplegia has always been questioned. However, clinical studies suggested sufficient protection and, up to now, intraoperative assessment of cardioplegia distribution has been difficult.

METHODS

As a pilot study in 14 patients, we used indocyanine green laser fluorescence angiography (ICGLA) to assess vascular and myocardial perfusion of different areas of the right anterior ventricular wall. Regions of interest were analyzed quantitatively using a new software package.

RESULTS

ICGLA allowed rapid and reliable visualization of cardioplegic flow and distribution. Retrograde cardioplegia revealed perfusion defects in the territory of the right anterior cardiac veins when compared to antegrade delivery and to areas close to the left anterior descending vein(s), confirmed by quantitative analyses of maximal fluorescence intensity. Five patients were excluded from quantitative analyses. The learning curve, pitfalls, limitations and special image details are described.

CONCLUSION

A larger study is necessary to examine the relevance of perfusion defects to metabolic changes in affected myocytes and to global right ventricular function.

Effect of antegrade graft cardioplegia combined with passive graft perfusion in on-pump coronary artery bypass grafting

Patients undergoing on-pump coronary artery bypass graft (CABG) with proximal graft anastomosis were randomly divided into groups that received antegrade cardioplegic infusion only via the aortic root (group A) or antegrade cardioplegic infusion via the aortic root and additional cardioplegia via vein or free arterial grafts after completion of each distal anastomosis (group B). The group B patients also received bypass graft perfusion with warm arterial blood just after removal of the cross-clamp until the proximal graft anastomosis was completed. The need for defibrillation and inotropic support during separation from cardiopulmonary bypass (CPB), and total CPB time were significantly lower in group B than in group A. Group B also had significantly lower peak cardiac troponin I levels 12 h after operation compared with group A and this was more pronounced in subgroups with severe right coronary artery stenosis and poor left ventricular ejection fraction than in the whole population. It is concluded that antegrade graft cardioplegia and graft perfusion with warm blood during proximal graft anastomosis may improve myocardial protection.

Management of the Valve and Ascending Aorta in Adults with Bicuspid Aortic Valve Disease

Bicuspid aortic valve (BAV) disease is the most common congenital cardiac malformation, being present in 1% to 2% of the population. It is heritable and is three to four times more likely to occur in men. The pathogenesis of BAV disease is unknown. Bicuspid valves progress to aortic stenosis or insufficiency in the majority of patients. BAV disease is associated with several anomalies of the aorta including coarctation, aneurysm formation, and dissection. Several lines of evidence suggest that aortic complications are caused by the same underlying factor that causes BAV disease, rather than being a consequence of turbulent blood flow through a stenotic valve. Several different surgical options exist for patients with BAV disease depending on the age of presentation and the size and appearance of the aorta. We herein describe our surgical management of the aortic valve and ascending aorta in patients with BAV disease.

Surgery for Chronic Total Occlusion of the Left Main Coronary Artery- Myocardial Preservation

We report seven patients with chronic total occlusion of the left main coronary artery that were operated in our institution and discuss the myocardial preservation options in these patients. In addition to total occlusion of the left main coronary artery, three patients also had severe lesions of right coronary artery. Prior myocardial infarction history and significantly depressed left ventricle functions were detected in all three patients with right coronary artery lesions. Five patients were operated on cardiopulmonary bypass while two patients were operated off pump. All patients received alternating antegrade/retrograde cardioplegia for myocardial preservation. In patients with simultaneous right coronary artery disease we first established the origin of the collaterals to the left coronary system. For patients with collaterals arising from the right coronary artery segment distal to the right coronary artery lesion, the antegrade component was administered through the saphenous vein graft bypassed to a distal part of right coronary artery segment. Thus we have achieved a more effective distribution of the antegrade cardioplegia. In off-pump-operated patients the left coronary system was revascularized before the right coronary system. Postoperative low cardiac output syndrome occurred in only one patient who was operated off pump. There was no operative and early mortality. Mean follow-up was 32 +/- 21.42 (range, 4 to 60) months. Alternating antegrade/retrograde cardioplegia was used with acceptable results in patients with total occlusion of the left main coronary artery. In patients with simultaneous RCA lesion we recommend regulation of the antegrade component based on the origin of collaterals that supplies the left coronary system. In off-pump-operated patients we suggest avoiding of clamping of right coronary artery at the beginning of the operation while it still supplies all the coronary circulation.

Myocardial Protection in Reoperative Coronary Artery Bypass Grafting:. Toward Decreasing Morbidity and Mortality

Redo coronary artery bypass grafting (CABG) is associated with higher morbidity and mortality when compared to first-time CABG. Myocardial infarction and dysfunction contribute significantly to the increased risk of redo CABG. Results of reoperative coronary surgery have gradually improved, largely because of improvements in myocardial protection techniques. In the present review we will highlight the principles of myocardial protection in redo CABG patients with an emphasis on retrograde cardioplegia.

Does antegrade blood cardioplegia alone provide adequate myocardial protection in patients with left main stem disease?

BACKGROUND

The optimum route for cardioplegia administration in patients with severe coronary disease is still under debate. This study compared clinical, echocardiographic, and biochemical results in patients with left main stem disease treated with 2 different strategies of myocardial protection.

METHODS

Between March 2000 and November 2002, 148 consecutive patients with left main stem disease undergoing coronary artery bypass grafting were divided into 2 groups according to the route of cardioplegia delivery: antegrade in 87 patients (group A) or antegrade followed by retrograde in 61 patients (group B). Electrocardiography, troponin I, MB-creatine kinase, and MB-creatine kinase mass were performed at 12, 24, 48, and 72 hours postoperatively. Echocardiography was performed preoperatively and before hospital discharge. Data were stratified in subgroups of patients with the following associated risk factors: left ventricular hypertrophy, diabetes, and right coronary stenosis.

RESULTS

Groups were homogeneous in preoperative and intraoperative variables, apart from the higher incidence of unstable angina and severity of left main stem disease in group B. Hospital deaths, intensive therapy unit and hospital stay, perioperative acute myocardial infarction, and intraaortic balloon pump support were similar in both groups. Postoperative recovery of left ventricle ejection fraction and wall motion score index did not differ between the 2 groups. However, postoperative atrial fibrillation was higher in group A (P =.015), especially in patients with diabetes (P <.0001). Troponin I was significantly higher in group A from postoperative hours 12 to 72 (P <.01), and the same pattern was observed in patients with diabetes (P <.001), critical right coronary stenosis (P <.001), and left ventricle hypertrophy (P <.001).

CONCLUSION

The combined route of intermittent blood cardioplegia allows better results in left main stem disease. Such data are confirmed even in risk subgroups.

The short-term and long-term effects of warm or tepid cardioplegia

BACKGROUND

Clinical studies of myocardial protection rarely identify differences in hard clinical outcomes after surgery, either early or late, because most trials lack sufficient statistical power to deal with low-frequency events.

METHODS

Prospectively collected data concerning all isolated coronary bypass operations from November 1989 to February 2000 were analyzed to determine the effects of cold blood cardioplegia and warm or tepid blood cardioplegia on early and late outcomes after surgery. Warm blood cardioplegia was used in 4532 patients, whereas cold blood cardioplegia was used in 1532. The allocation of patients to receive warm blood cardioplegia and cold blood cardioplegia was random in 749 cases and according to surgeon preference in the remainder. Most patients in the cold blood cardioplegia group had surgery earlier in the time course of the study, and most in the warm blood cardioplegia group underwent surgery later.

RESULTS

Perioperative death, myocardial infarction, and death or myocardial infarction were all more common in the cold blood cardioplegia group than in the warm blood cardioplegia group (death 2.5% vs 1.6%, P =.027, adjusted odds ratio 1.45, 95% confidence interval 0.95-2.22, P =.09; myocardial infarction 5.4% vs 2.4%, P <.0001, adjusted odds ratio 1.86, 95% confidence interval 1.36-2.53, P <.0001; death or myocardial infarction 7.3% vs. 3.8%, P <.0001, adjusted odds ratio 1.70, 95% confidence interval 1.30-2.21, P <.0001). Actuarial survival at 60 months was 91.1% +/- 1.4% in the warm blood cardioplegia group and 89.9% +/- 1.3% in the cold blood cardioplegia group (P =.09), whereas freedom from death or myocardial infarction was 84.7% +/- 1.8% and 83.2% +/- 1.6%, respectively (P =.16). In multivariate models, cold blood cardioplegia was associated with poorer survival (risk ratio 1.30, 95% confidence interval 0.96-1.75, P =.09) and freedom from any death or late myocardial infarction (risk ratio 1.93, 95% confidence interval 1.56-2.39, P =.0001).

CONCLUSIONS

In 6064 patients undergoing isolated coronary artery bypass grafting, warm or tepid blood cardioplegia may be associated with better early and late event-free survivals than is cold cardioplegia.

Myocardial infarction in coronary bypass surgery using on-pump, beating heart technique with pressure- and volume-controlled coronary perfusion

BACKGROUND

Even with the current aerobic techniques in myocardial protection, perioperative myocardial infarction can still occur. In this study, we sought to find out whether there is a method-specific mechanism of ischemic injury in coronary bypass surgery using an on-pump beating heart technique. For this reason, we investigated localization and the extent of myocardial infarction in correlation to the severity of coronary artery stenosis. We discuss strategies for reduction of infarction incidence.

METHODS

34 patients, who after isolated coronary bypass procedure developed non-Q or Q wave infarction were selected for the study. In 12 of 34 patients (group A) beating heart technique and in 22 of 34 patients (group B) cardioplegic arrest was used for myocardial protection. The study was conducted retrospectively and included patients with stable, unstable, and postinfarction angina without preoperative enzymatic evidence of ischemic injury and with technically noncomplicated coronary bypass grafting. Excluded from the study were emergency and redo procedures. In group A, in all instances, the left anterior descending artery was grafted as the last vessel and while distal anastomoses were constructed, coronary perfusion was maintained by using a perfusion catheter.

RESULTS

Most patients in both groups had triple-vessel disease (10 of 12 patients group A; 17 of 22 patients group B), all patients received complete revascularization; 7 of 12 patients in group A and 5 of 22 patients in group B had significant or critical left main stem stenosis. In group A, 11 infarctions occurred in LAD-(12 stenotic), 1 in CX-(11 stenotic), and 1 in RCA-(11 stenotic) supply area, four were Q wave infarctions. In group B, eight infarctions occurred in LAD (22 stenotic), four in CX (17 stenotic), and 14 in RCA (20 stenotic) supply area, eight were Q wave infarctions. In group A, the infarction incidence in the LAD area was 10-times higher than in CX and RCA areas. In group B, the infarction incidence in the RCA area was 2- and 3-times higher than in the LAD and CX areas, respectively. In both groups no correlation between infarction incidence and severity of stenosis was observed.

CONCLUSIONS

Using an on-pump beating heart technique, higher coronary perfusion pressures, avoidance of extreme upward retraction of the heart during revascularization of the CX-branch, as well as choosing the revascularization of the LAD as the first vessel, could possibly contribute to better myocardial protection. In hearts arrested with cardioplegic solution, the right ventricle is probably more susceptible to ischemic injury, especially when RCA is poorly collateralized. For adequate protection, choosing the revascularization of the RCA as the first vessel with immediate repeated cardioplegia via a RCA graft, higher perfusion pressures and antegrade with retrograde cardioplegia delivery, may be advantageous.

Neuropsychologic impairment after coronary bypass surgery: effect of gaseous microemboli during perfusionist interventions

OBJECTIVE

Neuropsychologic impairment is a common complication of coronary bypass surgery. Cerebral microemboli during cardiopulmonary bypass are the principal cause of cognitive deficits after coronary bypass grafting. We have previously demonstrated that the majority of cerebral emboli occur during perfusionist interventions (ie, during the injection of air into the venous side of the cardiopulmonary bypass circuit). The purpose of this study was to determine whether an increase in perfusionist interventions is associated with an increased risk of postoperative cognitive impairment.

METHODS

Patients undergoing elective coronary artery bypass grafting (n = 83) underwent a battery of neuropsychologic tests preoperatively and 3 months postoperatively. Patients were divided into 2 groups according to the median value of perfusionist interventions during cardiopulmonary bypass. Group 1 patients (n = 42) had fewer than 10 perfusionist interventions, and group 2 patients (n = 41) had 10 or more interventions.

RESULTS

The 2 groups of patients were similar for all preoperative, intraoperative, and postoperative variables, with the exception of longer cardiopulmonary bypass times in group 2 patients (P <.001). Group 2 patients had lower mean scores on 9 of 10 neuropsychologic tests, with 3 (Rey Auditory Verbal Learning, Digit Span, and Visual Span) being statistically significant. Group 2 patients had worse cognitive test scores, even when controlling for increased bypass times. Group 2 patients had a nonsignificant trend toward an increased prevalence of neuropsychologic impairment 3 months postoperatively.

CONCLUSIONS

Introduction of air into the cardiopulmonary bypass circuit by perfusionists, resulting in cerebral microembolization, may contribute to postoperative cognitive impairment.

Reoperative coronary bypass surgery: effect of patent grafts and retrograde cardioplegia

OBJECTIVE

To determine the effects of patent or diseased aorta-coronary bypass grafts and retrograde cardioplegia on mortality during reoperative coronary bypass surgery.

METHODS

We conducted a retrospective review of prospectively gathered data, supplemented by systematic chart review, of all patients (n = 744) undergoing reoperative coronary bypass surgery at our institution between 1990 and 1997. Independent predictors of survival were determined by stepwise logistic regression analysis.

RESULTS

At least one patent or stenosed graft to the left anterior descending artery was present in 50% of patients, to the circumflex territory in 27% of patients, and to the right coronary artery territory in 33% of patients. The previous left anterior descending graft was a saphenous vein in 82% and a left internal thoracic artery in 18% of patients. In-hospital mortality occurred in 42 (5.6%) patients. Patent or diseased grafts of any coronary artery territory did not significantly increase the risk of mortality. Retrograde cardioplegia use increased in more recent years, was more frequent in patients with stenosed grafts, and was associated with improved survival. Independent predictors of mortality were as follows (with odds ratios and 95% confidence intervals in parentheses): failure to use retrograde cardioplegia (odds ratio 2.81; 1.28-6.20), New York Heart Association class (odds ratio 2.69; 1.25-5.81), peripheral vascular disease (odds ratio 2.60; 1.25-5.41), and left ventricular grade (2.07; 1.31-3.27).

CONCLUSIONS

In this series, patent or stenosed grafts were not associated with an increased risk of mortality during reoperative coronary bypass surgery, possibly because of increased use of retrograde cardioplegia in this patient group. We strongly recommend the routine use of retrograde cardioplegia during redo coronary bypass surgery.