Anatomic and hemodynamic considerations influencing the efficiency of retrograde cardioplegia

Clinical anatomy of the coronary venous system and relevance to retrograde cardioplegia and cardiac electrophysiological interventions

Anomalies of coronary venous system, the valve of the coronary sinus (Thebesian valve) and other cardiac malformations may make interventions through the coronary sinus difficult. These variants may pose a challenge in cannulating the coronary sinus for retrograde cardioplegia and for interventions performed through the coronary sinus by cardiac electrophysiologist/interventional cardiologist. Retrograde cardioplegia is an established method of myocardial protection with advantages, indications, and complications. A good knowledge of the anatomy of the coronary sinus and its variants is important in understanding the difficulties encountered while cannulating the coronary sinus for the delivery of retrograde cardioplegia, cardiac resynchronization therapy, treatment of arrhythmias, and percutaneous mitral valve annuloplasty.

A Case of Coronary Sinus Atresia with a Total Anomalous Cardiac Venous Drainage to the Left Atrium without Persistent Left Superior Vena Cava: Imaging Findings on Cardiac CT

The coronary sinus (CS) is the venous drainage system of the heart. CS ostium atresia is a rarely seen cardiac malformation. Congenital atresia of the CS is usually found together with persistent left superior vena cava (LSVC) and other cardiac malformations. However, isolated congenital atresia of the CS is very rare. We present a rare case of isolated congenital atresia of the CS connecting the left atrium and coronary veins without persistent LSVC in a 58-year-old female.

A rare case of hypoplastic coronary sinus partially draining into right superior vena cava: A case report

BACKGROUND

The hypoplastic coronary sinus (CS) is a rare anomaly of the cardiac venous system, wherein some of the tributaries fail to join the CS. These tributaries usually drain into atrial chambers through dilated thebesian channels. We report the first case where the tributaries are draining into the right superior vena cava (SVC).

CASE SUMMARY

A case of ischemic cardiomyopathy with severe LV systolic dysfunction with NYHA class III symptoms was taken for CRTD implantation. CS venogram after direct cannulation from left subclavian access revealed a hypoplastic CS. The part of CS beyond the attachment of the oblique vein of the left atrium to CS (distal to the posterolateral vein) formed a common channel and was draining into the right-sided SVC. The posterolateral vein was of sufficient caliber so that an left ventricle (LV) lead could be implanted, and the CRTD procedure could be completed.

DISCUSSION

Hypoplastic CS though has no pathological significance in the normal population but for CRT it can become a significant limitation. Tributaries of CS draining into right SVC are the rarest of the finding, the channel draining most likely is a remnant of the splanchnic plexus around the embryonic foregut that usually has a temporary communication with cardinal veins during intrauterine growth. This communication somehow has persisted and resulted in a channel between coronary vein and the SVC, which may be referred to as coronary veno-cardinal vein.

Myocardial Protection in Minimally Invasive Mitral Valve Surgery: Retrograde Cardioplegia Alone Using Endovascular Coronary Sinus Catheter Compared With Combined Antegrade and Retrograde Cardioplegia

OBJECTIVE

To compare myocardial protection with retrograde cardioplegia alone with antegrade and retrograde cardioplegia in minimally invasive mitral valve surgery (MIMS).

DESIGN

Retrospective study.

SETTING

Tertiary care university hospital.

PARTICIPANTS

The authors studied 97 MIMS patients using retrograde cardioplegia alone and 118 MIMS patients using antegrade and retrograde cardioplegia.

INTERVENTIONS

The data from patients admitted for MIMS using retrograde cardioplegia (MIMS retro) between 2009 to 2012 were compared with the data from patients undergoing MIMS with antegrade and retrograde cardioplegia (MIMS ante-retro) between 2006 and 2010 (control group). Cardioplegia in the MIMS retro group was delivered solely through an endovascular coronary sinus (CS) catheter positioned under echographic and fluoroscopic guidance. Antegrade and retrograde cardioplegia was used in the MIMS ante-retro group. Data regarding myocardial infarction (MI; creatine kinase Mb, troponin T, electrocardiogram), myocardial function, and hemodynamic stability were collected for comparison.

MEASUREMENTS AND MAIN RESULTS

Adequate cardioplegia administration (CS pressure >30 mmHg and asystole) was attained in 74.2% of the patients with retrograde cardioplegia alone. In 23.7% of the patients, the addition of an antegrade cardioplegia was necessary. No difference was observed in the incidence of MI (0 MIMS retro v 1 for MIMS ante-retro, p = 0.3623), difficult separation from cardiopulmonary bypass, and postoperative malignant arrhythmia. No difference was found for maximal creatine kinase Mb (39.1 [28.0-49.1] v 37.9 [28.6-50.9]; p = 0.8299) and for maximal troponin T levels (0.39 [0.27-0.70] v 0.47 [0.32-0.79]; p = 0.1231) for MIMS retro and MIMS ante-retro, respectively. However, lactate levels in the MIMS retro group were significantly lower than in the MIMS ante-retro group (2.1 [1.4-3.05] v 2.4 [1.8-3.3], respectively; p = 0.0453). No difference was observed in duration of intensive care unit stay and death. MIMS retro patients had a shorter hospital stay (7.0 [6.0-8.0] v 8.0 [7.0-9.0] days; p = 0.0003).

CONCLUSION

Retrograde cardioplegia administration alone provided comparable myocardial protection to antegrade and retrograde cardioplegia during MIMS, but was not sufficient to achieve asystole in one-fifth of patients.

Coronary vasculature patterning requires a novel endothelial ErbB2 holoreceptor

Organogenesis and regeneration require coordination of cellular proliferation, regulated in part by secreted growth factors and cognate receptors, with tissue nutrient supply provided by expansion and patterning of blood vessels. Here we reveal unexpected combinatorial integration of a growth factor co-receptor with a heterodimeric partner and ligand known to regulate angiogenesis and vascular patterning. We show that ErbB2, which can mediate epidermal growth factor (EGF) and neuregulin signalling in multiple tissues, is unexpectedly expressed by endothelial cells where it partners with neuropilin 1 (Nrp1) to form a functional receptor for the vascular guidance molecule semaphorin 3d (Sema3d). Loss of Sema3d leads to improper patterning of the coronary veins, a phenotype recapitulated by endothelial loss of ErbB2. These findings have implications for possible cardiovascular side-effects of anti-ErbB2 therapies commonly used for cancer, and provide an example of integration at the molecular level of pathways involved in tissue growth and vascular patterning.

Semaphorin ligands and cognate receptors are important in patterning the vasculature. Here, Aghajanian et al. report an unexpected role for ErbB2 in endothelial cells where it partners with Nrp1 to form a novel semaphoring holoreceptor required for embryonic vascular patterning.

Clinical Results of Different Myocardial Protection Techniques in Aortic Stenosis

Background

Hypertrophied myocardium is especially vulnerable to ischemic injury. This study aimed to compare the early and late clinical outcomes of three different methods of myocardial protection in patients with aortic stenosis.

Methods

This retrospective study included 225 consecutive patients (mean age, 65±10 years; 123 males) with severe aortic stenosis who underwent aortic valve replacement. Patients were excluded if they had coronary artery disease, an ejection fraction <50%, more than mild aortic regurgitation, or endocarditis. The patients were divided into three groups: group A, which was treated with antegrade and retrograde cold blood cardioplegia; group B, which was treated with antegrade crystalloid cardioplegia using histidine-tryptophan-ketoglutarate (HTK) solution; and group C, treated with retrograde cold blood cardioplegia.

Results

Group A contained 70 patients (31.1%), group B contained 74 patients (32.9%), and group C contained 81 patients (36%). The three groups showed significant differences with regard to the proportion of patients with a New York Heart Association functional classification ≥III (p=0.035), N-terminal pro-brain natriuretic peptide levels (p=0.042), ejection fraction (p=0.035), left ventricular dimensions (p<0.001), left ventricular mass index (p<0.001), and right ventricular systolic pressure (p<0.001). Differences in cardiopulmonary bypass time (p=0.532) and aortic cross-clamp time (p=0.48) among the three groups were not statistically significant. During postoperative recovery, no significant differences were found regarding the use of inotropes (p=0.328), mechanical support (n=0), arrhythmias (atrial fibrillation, p=0.347; non-sustained ventricular tachycardia, p=0.1), and ventilator support time (p=0.162). No operative mortality occurred. Similarly, no significant differences were found in long-term outcomes.

Conclusion

Although the three groups showed some significant differences with regard to patient characteristics, both antegrade crystalloid cardioplegia with HTK solution and retrograde cold blood cardioplegia led to early and late clinical results similar to those achieved with combined antegrade and retrograde cold blood cardioplegia.

Analysis of myocardial temperature changes in conventional isolated coronary artery bypass grafting

Backgrounds

To determine whether cold blood cardioplegia (CBCP) can get over coronary artery lesions, we analyzed the relationship between myocardial temperature changes and lesion severity of major coronary arteries.

Methods and results

From April 1991 to October 2003, we measured myocardial temperature before and after antegrade and retrograde delivery of CBCP in 492 patients undergoing conventional coronary artery bypass grafting. Stenotic severity of three major coronary arteries was classified into four grades according to preoperative coronary arteriography; grade 0 for 50 % or less, 1 for 75 %, 2 for 90 %, 3 for 99 % or 100 %. We analyzed relationships between myocardial temperature changes [ΔT-A (antegrade) & ΔT-R (retrograde)] and the coronary artery lesion’s severity. Average ΔT-A of the right coronary artery had no relationship with stenotic grades. Mean ΔT-A of the left anterior descending (LAD) became less and less in proportion to its stenotic grade [9.7 °C for grade 0, 8.2 °C for grade 1, 7.1 °C for grade 2, and 6.0 °C for grade 3, respectively, (p = 0.0042)]. ΔT-A of the circumflex artery showed similar but weaker tendency than those of LAD. Significant inverse correlations were found between ΔT-A and ΔT-R1 in each territory (p < 0.001).

Conclusions

Antegrade delivery was less effective in situations with tight proximal lesion, especially in the LAD territory. Retrograde delivery supplemented antegrade delivery. Myocardial temperature monitoring enables us to deal with inadequate cardioplegic delivery, and is a good indicator of myocardial protection.

Anomalous great cardiac vein draining into the right atrium combined with a single left coronary artery

In contrast to the coronary arterial system, little attention has been paid to the coronary venous system in previous literature. We report a rare case of a combined anomaly of the coronary artery and the great cardiac vein (GCV). In this patient, the right coronary artery (RCA) arose from the left coronary artery, and the GCV drained directly into the right atrium. The anomalous RCA and GCV ran parallel courses along the anterior side of the right ventricular outflow tract. We briefly review the clinical significance and the role of cardiac computed tomography in this anomaly.

Adenosine in cold blood cardioplegia--a placebo-controlled study

OBJECTIVE Adenosine as an additive in blood cardioplegia is cardioprotective in animal studies, but its clinical role in myocardial protection remains controversial. The aim of this study was to investigate whether the addition of adenosine in continuous cold blood cardioplegia would enhance myocardial protection. METHODS In a prospective double-blind study comparing adenosine 400 μmol l(-1) to placebo in continuous cold blood cardioplegia, 80 patients undergoing isolated aortic valve replacement were randomized into four groups: antegrade cardioplegia with adenosine (n = 19), antegrade cardioplegia with placebo (n = 21), retrograde cardioplegia with adenosine (n = 21) and retrograde cardioplegia with placebo (n = 19). Myocardial arteriovenous differences in oxygen and lactate were measured before, during and after aortic occlusion. Myocardial concentrations of adenine nucleotides and lactate were determined from left ventricular biopsies obtained before aortic occlusion, after bolus cardioplegia, at 60 min of aortic occlusion and at 20 min after aortic occlusion. Plasma creatine kinase (CK-MB) and troponin T were measured at 1, 3, 6, 9, 12 and 24 h after aortic occlusion. Haemodynamic profiles were obtained before surgery and 1, 8 and 24 h after cardiopulmonary bypass. Repeated-measures analysis of variance was used for significance testing. RESULTS Adenosine had no effects on myocardial metabolism of oxygen, lactate and adenine nucleotides, postoperative enzyme release or haemodynamic performance. When compared with the antegrade groups, the retrograde groups showed higher myocardial oxygen uptake (17.3 ± 11.4 versus 2.5 ± 3.6 ml l(-1) at 60 min of aortic occlusion, P < 0.001) and lactate accumulation (43.1 ± 20.7 versus 36.3 ± 23.0 µmol g(-1) at 60 min of aortic occlusion, P = 0.052) in the myocardium during aortic occlusion, and lower postoperative left ventricular stroke work index (27.2 ± 8.4 versus 30.1 ± 7.9 g m m(-2), P = 0.034). CONCLUSIONS Adenosine 400 μmol l(-1) in cold blood cardioplegia showed no cardioprotective effects on the parameters studied. Myocardial ischaemia was more pronounced in patients receiving retrograde cardioplegia.

Multidetector CT findings of a congenital coronary sinus anomaly: a report of two cases

Congenital coronary sinus anomalies are extremely rare, and they have received relatively little attention. This is probably due to the lack of both clinical symptoms and significant cardiac functional disturbance. We present two cases of a coronary sinus anomaly and briefly review the literature. Recognizing and being familiar with the variations of a congenital coronary sinus anomaly in congenital heart disease may avoid a misinterpretation of cardiac catheterization findings and the troublesome disruption of coronary sinus blood return during the surgical management of cardiac lesions.

Coronary venous retroperfusion: an old concept, a new approach

The potential of the coronary veins for revascularization has been evaluated by many investigators for more than a century. The major hurdle has been the damage of veins during sudden exposure to arterial pressure. The solution to this problem has typically involved the use of intricate and complicated apparatus and devices, which has prevented routine clinical utility in the catheterization laboratory. This review examines this old concept from a new perspective and proposes a novel hypothesis to address previous shortcomings. We speculate on an approach that may serve to eliminate the edema and hemorrhage that result during venous retroperfusion as the pressure is suddenly increased to arterial values. We propose the rationale to increase the venous pressure to arterial values more gradually to allow prearterializations of the veins before full exposure of arterial pressure. Finally, we discuss various possible indications for this selective autoretroperfusion strategy to combat myocardial ischemia in cardiogenic shock patients, ST-elevation myocardial infarct patients, no-option patients, and beyond.

Occluding the junction of the middle cardiac vein in retrograde cardioplegia: a new retrograde cannula for optimizing retrograde cardioplegic delivery

Retrograde cardioplegia often fails to provide adequate perfusion of the right ventricle and the posterior wall of the left ventricle because of the shunt through the thebesian vein. However, much of the retrograde cardioplegic solution may leak into the right atrium after veno-venous anastomoses at the apex of the heart, especially when a retrograde balloon cannula is inserted too deeply in the great cardiac vein, although this is not widely recognized. We designed a new retrograde cardioplegic cannula with three self-inflating balloons, which reduced the shunt flow by occluding the junction of the middle cardiac vein and improving in cardioplegic delivery. We describe the myocardial dye distribution achieved by using this new cannula in pig hearts and report the results of its clinical application.

Cardiopulmonary bypass for adults with congenital heart disease: pitfalls for perfusionists

The fixed incidence of congenital heart defects and improved survival have resulted in increasing numbers of adults with congenital heart disease (CHD) who have undergone complex repairs and/or palliations. Eventually, there will be more adults with CHD than children. They will require cardiac surgical interventions associated with progression of their CHD or for age-related disease, such as coronary revascularization. During bypass, anatomical shunts may exist within or without the heart. Left-to-right shunts can result in dramatically lower systemic blood flow than pump flow due to 'steal', while pulmonary edema ensues due to excessive pulmonary flow. Right-to-left shunts carry risks of massive air embolism and double or triple venous cannulation may be necessary. Cannulation of composite reconstructed aortas may be difficult, risking dissection or aortic obstruction, and double arterial cannulation may be indicated. Aberrant coronary arterial and venous anatomy may .preclude adequate myocardial preservation with common techniques and can be complicated by aortic insufficiency. Valves and conduits may exhibit failure. Conventional monitoring, such as central venous oximetry, may be misleading. Monitoring, such as serial lactate measurement, near-infrared spectroscopy and transcranial Doppler blood velocity, offer advantages for such patients. The perfusionist needs to be aware of such conditions as much congenital aberrancy may present unexpectedly during cardiac surgery.

Targeted cell delivery into infarcted rat hearts by retrograde intracoronary infusion: distribution, dynamics, and influence on cardiac function

BACKGROUND

Intracoronary infusion for cell transplantation has potential advantages in disseminating cells globally into the myocardium with less injury over direct intramuscular injection. Arterial route, however, has a risk of coronary embolism and a limitation in cell delivery into ischemic or infarcted areas. We assessed the efficiency of retrograde intracoronary cell implantation into infarcted hearts using a novel rat model.

METHODS AND RESULTS

After left coronary artery ligation in rat, a catheter was inserted into the left cardiac vein, which drains the left ventricular free wall. Through this, 1x10(6) skeletal muscle precursor cells expressing nuclear beta-galactosidase were infused retrogradely into the vein. In situ staining demonstrated that beta-galactosidase-expressing donor cells had disseminated throughout the left ventricular free wall, including both infarcted and surrounding border areas, at 10 minutes after infusion. At 28 days, in contrast, positively stained multinuclear myotubes were found in border zones, whereas no positive cells were seen in infarcted areas. Measurement of beta-galactosidase enzyme activity estimated that 29.8+/-6.9% of total infused cells were retained within the myocardium at 10 minutes and that this number decreased to 23.7+/-8.1% at 3 days but rapidly increased thereafter, reaching a plateau at 90.2+/-17.1% by 14 days. Echocardiography and Langendorff perfusion demonstrated that cell implantation improved cardiac function and dimensions by 28 days, compared with both sham-treated and phosphate-buffered saline-infused infarcted hearts, and this was associated with decreased collagen deposition.

CONCLUSIONS

Retrograde intracoronary cell transplantation could provide an effective cell delivery into infarcted hearts and could be a useful strategy for treating myocardial infarction.

Optimal continuous retrograde coronary perfusion flow rate with beating heart in normal temperature

PURPOSE

We were led to the premise that with retrograde oxygenated blood perfusion, it would be possible to perform operations on the beating heart.

METHODS

The experiment consisted of two stages: procedure 1 and 2. In procedure 1, six pigs were used. Retrograde perfusion flow was controlled to be in the range of 5.0-10.0 mL/kg/min and was gradually increased. In procedure 2, six pigs were used. Retrograde perfusion was continued for 120 min at the optimal flow rate obtained from procedure 1.

RESULTS

The optimal flow rate was 7.0 mL/kg/min in procedure 1. In procedure 2, retrograde perfusions for 120 min were performed with perfusion flows set at optimal flow rate.

CONCLUSIONS

The procedure used in this study made it possible to maintain empty beating heart with normal sinus rhythm for 120 min, and the results suggest the possibility of clinical application to open heart surgery.

Myocardial protection with intermittent cold blood during aortic valve operation: antegrade versus retrograde delivery

BACKGROUND

Intermittent antegrade cold blood cardioplegia is superior to warm blood cardioplegia in patients who have aortic valve operation. This study compared the cardioprotective efficacy of intermittent antegrade and retrograde cold blood cardioplegia with emphasis on metabolic stress in the left and right ventricles.

METHODS

Thirty-nine patients who had elective aortic valve replacement were prospectively randomly selected to receive intermittent antegrade or retrograde cold blood cardioplegia. Left and right ventricular biopsies were collected 5 minutes after institution of cardiopulmonary bypass and 20 minutes after cross-clamp removal and were used to determine metabolic changes. Metabolites (adenine nucleotides, amino acids, and lactate) were measured using high-powered liquid chromatography and enzymatic techniques. Serial measurement of troponin I release was also used as a marker of myocardial injury.

RESULTS

Preoperative characteristics were similar between groups. There was no in-hospital mortality, and no differences were observed in postoperative complications. Preischemic concentration of taurine was significantly higher in left ventricular biopsies, whereas adenosine triphosphate tended to be lower in the left ventricle. At reperfusion adenosine triphosphate levels were significantly lower than preischemic levels in right but not left ventricles irrespective of the route of delivery. The alanine-glutamate ratio was significantly elevated in both ventricles. Myocardial injury as assessed by troponin I release was also significantly increased in both groups.

CONCLUSIONS

Retrograde and antegrade intermittent cold blood cardioplegic techniques are associated with suboptimal myocardial protection. Metabolic stress was more pronounced in the right than the left ventricle irrespective of the cardioplegic route of delivery used.