Antegrade and retrograde infusion of cardioplegia: assessment by thermovision

The efficacy of two routes of cardioplegia infusion was examined by assessing the hypothermia induced in patients with critically obstructed or occluded major coronary arteries. The antegrade (through the aorta) and the retrograde (through the coronary sinus) methods of cardioplegia infusion were compared using myocardial thermograms. Patients (N = 8) were matched according to angiographic similarities of their coronary artery disease. Adequate myocardial cooling distal to a critical obstruction could frequently not be obtained with antegrade infusion of cardioplegic solution. With retrograde infusion, the desired uniform cooling of the myocardium, as determined by thermographic analysis of the surface temperatures of the heart, was obtained. We conclude that retrograde infusion of cardioplegic solution induces more effective and homogeneous hypothermia in patients with critically obstructive multivessel coronary disease, and may provide improved myocardial protection.     

The effects of retrograde cardioplegia technique on myocardial perfusion and energy metabolism: a magnetic resonance imaging and localized phosphorus 31 spectroscopy study in isolated pig hearts

OBJECTIVE: The present work was designed to study the myocardial perfusion and energy metabolism during retrograde cardioplegia performed with different methods, including deep coronary sinus cardioplegia, coronary sinus orifice cardioplegia, and right atrial cardioplegia. METHODS: Isolated pig hearts were subjected to antegrade cardioplegia, right atrial cardioplegia, deep coronary sinus cardioplegia, and coronary sinus orifice cardioplegia in a random order. Cardioplegic distribution was assessed by T1-weighted magnetic resonance imaging in 1 group of hearts (n = 8). The flow dynamics of cardioplegia were assessed by T2*-weighted imaging in a second group of hearts (n = 8). RESULTS: T1-weighted images revealed an apparent perfusion defect in the posterior wall of the left ventricle, the posterior portion of the interventricular septum, and the right ventricular free wall during deep coronary sinus cardioplegia. The perfusion defect observed in the first 2 regions with deep coronary sinus cardioplegia resolved with coronary sinus orifice cardioplegia. Right atrial cardioplegia provided the most homogeneous perfusion to all regions of the myocardium relative to the other 2 retrograde cardioplegia modalities. T2*-weighted images showed that the 3 retrograde cardioplegia modalities provided similar cardioplegic flow velocities. Localized phosphorus 31 spectroscopy showed that the levels of adenosine triphosphate and phosphocreatine were significantly lower in the posterior wall (adenosine triphosphate, 42.86% +/- 5.91% of its initial value; phosphocreatine, 11.43% +/- 11.3%) than the anterior wall (adenosine triphosphate, 89.19% +/- 8.83%; phosphocreatine, 59.54% +/- 12.58%) of the left ventricle during 70 minutes of normothermic deep coronary sinus cardioplegia. CONCLUSIONS: Deep coronary sinus cardioplegia results in myocardial ischemia in the posterior wall of the left ventricle and the posterior portion of the interventricular septum, as well as in the right ventricular free wall. Coronary sinus orifice cardioplegia improves cardioplegic distribution in these regions. Relative to deep coronary sinus cardioplegia and coronary sinus orifice cardioplegia, right atrial cardioplegia provides the most homogeneous perfusion.     

Electrophysiological evaluation of retrograde cardioplegia--experimental study of efficacy for the right ventricle

Recently, coronary artery bypass grafting operations for patients with total proximal multi-vessel coronary obstructions are increased. In these cases, antegrade cardioplegia through the aortic root has been applied as usual. But it seems to be difficult to deliver cardioplegic solution to myocardium uniformly beyond coronary stenosis. Retrograde coronary sinus cardioplegia in the presence of proximal coronary artery obstruction could maintain improved cardioplegic delivery and satisfactory myocardial protection. Because of the limitation of antegrade cardioplegia, retrograde cardioplegic technique has, once again, been cited as a reasonable alternative to antegrade cardioplegia. But on the other hand, retrograde cardioplegia includes the potential for relatively inadequate preservation of right ventricle based on the venous drainage communication to the coronary sinus. The object of the present work is mainly to evaluate the efficacy of retrograde coronary sinus cardioplegic technique for right ventricle by electrophysiological method. Thirty-six adult mongrel dogs divided three groups. Sixteen animals (Group I) received GIK cardioplegia through the coronary sinus, thirteen animals (Group II) received GIK added diltiazem cardioplegia through the same way, and seven animals (Group III) received GIK cardioplegia through aortic root. No large temperature gradients of myocardium between right and left ventricle in each group and also temperature gradients of right ventricle between three groups have been observed. The time duration from starting of injection of cardioplegia to disappear the electrical activity in right and left ventricle were 11.4 +/- 8.2, 3.4 +/- 1.2 minutes in group I, 2.9 +/- 1.5, 2.2 +/- 1.4 minutes in group II, and 0.9 +/- 0.4, 0.9 +/- 0.2 minutes in group III. The time duration from starting of injection of cardioplegia to reappear the electrical activity in right and left ventricle were 6.4 +/- 8.7, 13.4 +/- 7.9 minutes in group I, 20.0 +/- 3.5, 21.3 +/- 1.6 minutes in group II and 18.0 +/- 5.5, 18.7 +/- 4.5 minutes in group III. Unipolar peak-to-peak amplitude (UPPA) analysis reveals the condition of myocardial preservation during ischemic arrest and we compared preischemic UPPA with post-ischemic UPPA. In group I, UPPA declined of 44.1 +/- 29.3% in right ventricle and 72.7 +/- 27.6% in left ventricle, in group II, 78.7 +/- 28.7%, 81.9 +/- 23.6%, in group III, 71.4 +/- 18.7%, 76.7 +/- 9.89%. Analysis of ultrastructural changes in the myocardium are shown that injury was most manifest in the right ventricle of group I, but in group II, ultrastructure of right ventricle maintained nearly normal condition.(ABSTRACT TRUNCATED AT 400 WORDS)     

A new technique for delivering antegrade/retrograde blood cardioplegia without right heart isolation

We report our updated experience with combined antegrade/retrograde cardioplegia using a self-inflating/deflating balloon cannula that allows rapid transatrial retrograde coronary sinus cannulation (10-15 s) without right heart isolation. This permits routine single venous cannulation and optimizes myocardial protection when combined with antegrade cardioplegia. Two hundred fifty-five consecutive patients underwent antegrade/retrograde cardioplegia. Initial antegrade blood cardioplegia caused immediate arrest (less than 1 min), and the cardioplegic dose was divided equally between antegrade and retrograde delivery. Included are 173 isolated CABG patients (39 with either extending infarction, cardiogenic shock, or ejection fraction less than 20%), and 37 coronary reoperations, 67 with aortic and/or mitral valve procedures, 3 with arrhythmia surgery, and 7 children (VSD, Rastelli, Konno, etc). Septal temperature in patients with LAD occlusion fell to 11.6 degrees C +/- 0.5 after retrograde vs only 16.1 degrees C +/- 3 after antegrade cardioplegia (p less than 0.05). Overall hospital mortality was 2.8% and no complications followed transatrial retrograde coronary sinus cannulation. Antegrade/retrograde cardioplegia allowed retrograde flushing of debris in redo coronary operations, produced immediate arrest with low cardioplegic volumes, improved cardioplegic distribution during IMA grafting, allowed aortic and mitral valve procedures to proceed uninterrupted, and ensured distribution in unforeseen aortic insufficiency. Antegrade/retrograde cardioplegia is now used routinely in all adult and in many pediatric operations because of its speed, safety, and simplicity.     

A new simplified method of optimizing cardioplegic delivery without right heart isolation. Antegrade/retrograde blood cardioplegia

We report our initial experience with antegrade/retrograde cardioplegia using a self-inflating/deflating balloon cannula that allows rapid transatrial retrograde cannulation of the coronary sinus (10 to 15 seconds) without right heart isolation and permits routine single venous cannulation. We subjected 141 consecutive adult patients and nine children to antegrade/retrograde cardioplegia using rapid transatrial insertion of the Retroplegia cannula (Research Medical, Inc., Salt Lake City, Utah). Single venous cannulation was used in 116 patients having coronary artery bypass grafting or aortic valve replacement, or both. Initial antegrade blood cardioplegia caused immediate arrest (less than 1 minute) and the cardioplegic dose was divided equally between antegrade and retrograde delivery. Included are 95 patients having isolated bypass grafting (34 with extending infarction, cardiogenic shock, or ejection fraction less than 20%); 19 having coronary reoperations, 42 with aortic or mitral valve procedures, or both; and nine children having repair of congenital defects (e.g., repair of ventricular septal defect, Rastelli operation, Konno operation). Septal temperature in patients with occlusion of the left anterior descending coronary artery fell to 11.5 degrees +/- 0.5 degrees C after retrograde cardioplegia versus only 16 degrees +/- 3 degrees C after antegrade cardioplegia (p less than 0.05). The overall hospital mortality rate was 2% and no complications followed transatrial retrograde cannulation of the coronary sinus.     

Superiority of retrograde cardioplegia after acute coronary occlusion

Because antegrade cardioplegia may limit the distribution of cardioplegia beyond a coronary occlusion, this study was undertaken to determine whether retrograde coronary sinus cardioplegia provides superior myocardial protection during revascularization of an acute coronary occlusion. In 20 adult pigs, the second and third diagonal branches were occluded with a snare for 1 1/2 hours. Animals were then placed on cardiopulmonary bypass and underwent 30 minutes of ischemic arrest with multidose, potassium, crystalloid cardioplegia. In 10 animals, the cardioplegia was given antegrade through the aortic root, whereas in 10 others, it was given retrograde through the coronary sinus. After the arrest period, the coronary snares were released and all hearts were reperfused for 3 hours. Postischemic damage in the myocardium beyond the occlusions was assessed by wall motion scores using two-dimensional echocardiography (4 = normal to -1 = dyskinesia), the change in myocardial pH from preischemia, and the area of necrosis/area of risk (histochemical staining). Hearts protected with retrograde coronary sinus cardioplegia had less tissue acidosis (change in pH = 0.08 +/- 0.03 versus 0.41 +/- 0.13; p less than 0.05), higher wall motion scores (2.0 +/- 0.6 versus 1.3 +/- 0.3; not significant), and less myocardial necrosis (43.4% +/- 3.6% versus 73.3% +/- 3.5%; p less than 0.0001). We conclude that retrograde coronary sinus cardioplegia provides more optimal myocardial protection than is possible with antegrade cardioplegia after revascularization of an acute coronary occlusion.     

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.     

Studies of retrograde cardioplegia. II. Advantages of antegrade/retrograde cardioplegia to optimize distribution in jeopardized myocardium

This study tests the hypothesis that retrograde/antegrade cardioplegic delivery can overcome the limitations of poor cardioplegic distribution resulting from either technique alone and, potentially, may expand the safety of using internal mammary artery grafts in cardiac muscle in jeopardy of inadequate cardioplegic protection. Jeopardized myocardium was produced in 20 dogs by ligating the left anterior descending coronary artery for 15 minutes before starting cardiopulmonary bypass and by 1 hour of aortic clamping with multidose 6 degrees C cold blood cardioplegia. Five dogs received antegrade cardioplegia via the aortic root. Ten dogs received retrograde cardioplegia via the coronary sinus. Five additional dogs received retrograde/antegrade cardioplegia via both routes. The ligature on the left anterior descending coronary artery was removed after aortic unclamping, and regional myocardial temperature (thermistor probe), segmental shortening (ultrasonic crystals), and global left ventricular and right ventricular myocardial function were evaluated. Antegrade cardioplegia produced excellent right ventricular cooling (14 degrees C) and allowed complete right ventricular functional recovery. However, it failed to cool muscle supplied by the left anterior descending coronary artery (only 31 degrees versus 12 degrees C, p less than 0.05), postischemic global left ventricular function recovered only 38% (p less than 0.05), and segmental shortening in the region supplied by the left anterior descending coronary artery recovered only 22% (p less than 0.05). Retrograde cardioplegia produced homogeneous cooling (17 degrees C) and allowed near normal recovery of global and regional left ventricular function (99% and 86%), but right ventricular cooling was variable (19 degrees to 30 degrees C) and right ventricular function recovered inconstantly (range 64% to 100%, average 82%). The best myocardial protection occurred after retrograde/antegrade cardioplegia; myocardial cooling was homogeneous, left ventricular and right ventricular global function recovered completely (95% and 90%), and regional contractility in muscle supplied by the left anterior descending coronary artery returned to 84% of control. We conclude that retrograde/antegrade cardioplegia provides better myocardial protection than either technique alone, ensures good cardioplegic distribution to the left and right ventricles, and allows regional delivery of cardioplegic flow to segments supplied by occluded arteries.(ABSTRACT TRUNCATED AT 400 WORDS)     

Retrograde versus antegrade cardioplegia: impact on right ventricular function.

Retrograde cardioplegia administered through the coronary sinus has several documented advantages over antegrade cardioplegia but has been thought to provide inadequate right ventricular myocardial protection. We prospectively compared the effects of retrograde and antegrade cardioplegia on right ventricular performance in patients undergoing myocardial revascularization. Two groups of similar age, extent of disease, and preoperative left ventricular ejection fraction received retrograde (n = 16) or antegrade (n = 14) crystalloid cardioplegia. A right ventricular rapid-response thermistor catheter, previously developed and validated in our institution, was used to measure right atrial pressure, pulmonary artery pressure, right ventricular ejection fraction, end-diastolic volume index, and stroke volume index before bypass (baseline) and at several intervals after bypass. There were no differences in cross-clamp time, heart rate, cardiac enzymes, inotrope requirements, or arrhythmias between the two groups. Right ventricular parameters were equivalent in both groups at all time intervals except 30 minutes after bypass, at which time right ventricular end-diastolic volume index was lower (80 +/- 6 versus 93 +/- 6 mL/m2; p less than 0.05) and right ventricular stroke volume index was higher (35 +/- 3 versus 29 +/- 2 mL/m2, p less than 0.05) in the retrograde group compared with the antegrade group, indicating better right ventricular function with retrograde cardioplegia early after bypass. In both groups, right ventricular end-diastolic volume index was higher than baseline (p less than 0.05) during the first 4 hours after bypass. No other important differences were found.(ABSTRACT TRUNCATED AT 250 WORDS)     

Retrograde continuous cold blood cardioplegia via coronary sinus]

Though the retrograde continuous cold blood cardioplegia (RC-CBCP) is a useful method of myocardial protection for more complicated cardiac surgery, the most important problem is whether the right ventricle is satisfactorily protected or not. In the present study 60 patients with valvular heart disease given RC-CBCP were compared with 30 patients given antegrade continuous cold blood cardioplegia. Judging from myocardial temperature measured in the right ventricular wall, the ventricular septum and the left ventricular wall at the end of initial cardioplegic infusion, myocardial distribution of cardioplegic solution in the RC-CBCP group was as favorable as in the antegrade group. Injury to mitochondria in the right ventricular myocardium observed in the biopsy specimen taken just prior to aortic unclamping was usually trifling in the RC-CBCP group, and was not different significantly from that in the antegrade group. Cold blood cardioplegia dose perfused per left ventricular mass weight (LVMW) had significant correlation with injury to mitochondria, and the dose of more than 5ml/100gLVMW/min seemed to be preferable. There was no hospital death in all patients. Peak CK-MB after unclamping was less in the RC-CBCP group than the antegrade group. In conclusion, RC-CBCP is a safe and effective means of myocardial protection for both right and left ventricles.     

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.     

A Comparison of Distribution Between Simultaneously or Sequentially Delivered Antegrade/Retrograde Blood Cardioplegia

A bstract Commercially available cardioplegia delivery systems now allow for antegrade (aortic root, coronary ostia, saphenous vein graft) perfusion to occur either sequentially or simultaneous with retrograde (coronary sinus) perfusion. This study was designed to compare the total flow and local distribution of sequential versus simultaneous antegrade/retrograde cardioplegia delivery. Methods : Explanted human hearts diagnosed with idiopathic cardiomyopathy underwent a cold cardioplegic arrest and bicaval cardiectomy. Thirty-seven degree centigrade blood cardioplegia containing colored microspheres was then delivered antegrade (red color) at a pressure of 80 mmHg or retrograde (blue color) at a pressure of 40 mmHg. In the sequential group (n = 6), cardioplegia was delivered antegrade and then retrograde for 2 minutes, respectively. For the simultaneous group (n = 6), cardioplegia was delivered both antegrade and retrograde for 2 minutes. The ventricular myocardium was then sampled at 12 representative sites to determine regional cardioplegic flow. Results : Mean total cardioplegia delivery/minute was 0.69 ± 0.62 mL/g per minute for sequential cardioplegia, and 0.46 ± 0.19 mL/g per minute for simultaneous cardioplegia (p > 0.05, NS). At the 12 ventricular sites sampled, mean regional cardioplegic flow (mL/g per min) was in general slightly greater for sequential delivery. However, this was not statistically significant (p > 0.05, NS). Conclusion : The data suggest that there may be a slight advantage in total cardioplegia delivery and regional cardioplegia delivery when using sequential rather than simultaneous cardioplegia delivery. However, this difference was not statistically significant and is likely not of clinical significance. Therefore, we would recommend using either sequential or simultaneous antegrade/retrograde cardioplegia based upon whichever technique facilitates the conduct of the individual operation.     

Assessment of retrograde cardioplegia distribution using contrast echocardiography

Retrograde cardioplegia has gained popularity in coronary and noncoronary cardiac operations. We have used contrast echocardiography in the open-chest canine model to compare the distribution of cardioplegia delivered antegrade in the aortic root versus retrograde through the coronary sinus, and to determine the effect of coronary occlusion on that delivery. With no coronary occlusion, antegrade cardioplegia was distributed to the entire left ventricle and septum whereas retrograde cardioplegia was distributed to the left ventricular free wall but had inconsistent delivery to the septum. Acute occlusion of the left circumflex coronary artery resulted in 57.06% +/- 9.52% of the left ventricle not being perfused by antegrade cardioplegia and occlusion of both the left circumflex and anterior descending coronary arteries caused a 65.46% +/- 18.5% reduction in perfusion by antegrade cardioplegia. Acute coronary occlusion had no effect on retrograde cardioplegia distribution. We conclude that retrograde cardioplegia is less homogeneous than antegrade cardioplegia in the intact coronary circulation but that retrograde cardioplegia preserves cardioplegia distal to acutely occluded coronary arteries. Furthermore, contrast echocardiography is a useful method of assessing myocardial perfusion and may have useful clinical applications.     

Facile retrograde cardioplegia: transatrial cannulation of the coronary sinus

The benefits of coronary sinus (CS) cardioplegia are well known, yet CS cardioplegia is not used widely owing to the need for bicaval cannulation, snares, and an atriotomy. We designed and used in 225 consecutive patients a catheter containing a flexible removable stylet that, when shaped into a hockey-stick configuration, enabled blind intubation of the CS through a small pursestring in the right atrium, guided easily into the CS using a finger on the atrioventricular groove at the inferior vena cava. The CS was intubated in all patients; a pressure-limited balloon at the catheter tip was inflated after cross-clamping. An integral distal pressure line measured CS pressure. Catheters were placed distally within the great cardiac vein beyond the posterior interventricular vein; the position did not alter cooling: right ventricular free wall, septum, and left ventricular free wall temperatures were 7 degrees +/- 2 degrees, 8 degrees +/- 2 degrees, and 7 degrees +/- 2 degrees C, respectively, after an initial 10 mL/kg of blood cardioplegia. Transatrial CS cardioplegia was used in 45 aortic valve replacements, 22 mitral valve replacements, 4 triple-valve replacements, 6 congenital lesions, and 148 coronary revascularizations, including 40 redo operations. Atheromatous material was routinely flushed retrogradely from cut old vein grafts during revascularization; 70 revascularizations (47%) were performed urgently for acute infarction or jeopardized myocardium. No heart block or CS injury occurred, and inotrope use dropped to 10% of patients (from 38% in the previous 256 patients with antegrade blood cardioplegia). We conclude that the CS can be cannulated transatrially and that CS cardioplegia is more facile than antegrade cardioplegia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coronary Sinus Injury During Retrograde Cardioplegia: A Report of Three Cases

A bstract Coronary sinus injuries related to the use of retrograde cardioplegia are uncommon. In most cases injuries are encountered with overinflation of the coronary sinus catheter balloon or traumatic catheter insertion. This article describes three cases of coronary sinus injury during retrograde cardioplegia administration in patients with ventricular hypertrophy, while the heart was manually retracted to expose the posterior myocardium. We propose that the risk of coronary sinus injury during retrograde cardioplegia, in patients with left ventricular hypertrophy, can be minimized by avoiding excessive retraction of the heart, deflation of the retrograde catheter during retraction, and the use of a left ventricular vent.     

Warm retrograde cardioplegia. Protection of the right ventricle in mitral valve operations.

Hypothermia is believed to be the most important aspect of successful myocardial protection with retrograde coronary sinus cardioplegia. Because nutritive capillary flow to the right ventricle and septum is thought to be diminished with retrograde perfusion, these areas of the myocardium are considered at higher risk for intraoperative deterioration without the added protection of hypothermia. Recently we introduced warm aerobic arrest as an alternative to conventional methods of myocardial protection. We present our clinical results in 37 patients with mitral valve disease (+/- aortic valve, aortic root, or coronary artery disease) who underwent various cardiac procedures for which warm blood cardioplegic solution was delivered continuously via the coronary sinus after antegrade arrest. Thirty-five of the patients were in New York Heart Association class III or IV, and 19 patients had grade 3 or grade 4 left ventricular function. Sixteen patients had pulmonary hypertension, three with suprasystemic pressures, and marked right ventricular hypertrophy. Two patients had associated left ventricular hypertrophy. Nearly all patients returned to normal sinus rhythm shortly after removal of the aortic crossclamp, and they were easily discontinued from cardiopulmonary bypass even with crossclamp times of 3 hours. The 30-day hospital mortality rate was 2.7%. The perioperative myocardial infarction rate was 5.4%, and the prevalence of low-output syndrome was 10.8%. The results suggest that retrograde coronary sinus perfusion of blood cardioplegic solution at 37 degrees C is an effective method of myocardial protection even in patients with pulmonary hypertension at high risk for right ventricular failure. Its efficacy in this circumstance does not reside in its ability to deliver hypothermia.     

Retrograde coronary sinus perfusion prevents infarct extension during intraoperative global ischemic arrest

To determine whether continuous infusion of cardioplegia retrograde through the coronary sinus could improve the salvage of infarcting myocardium, 54 pigs were utilized in a region at risk model. All hearts underwent 30 minutes of reversible coronary artery occlusion, and were divided into six groups. Group 1 served as controls and underwent two hours of coronary reflow without global ischemic arrest. The remaining five groups were subjected to 45 minutes of cardioplegia-induced hypothermic arrest followed by two hours of normothermic reflow. Group 2 had a single infusion of crystalloid cardioplegia, and Group 3 received an oxygenated perfluorocarbon cardioplegic solution initially and again after 20 minutes of ischemia. After initial cardiac arrest with crystalloid cardioplegia, all hearts in Groups 4, 5, and 6 underwent a continuous infusion of a cardioplegic solution retrograde through the coronary sinus. Group 4 received a nonoxygenated crystalloid cardioplegic solution, Group 5 received an oxygenated crystalloid cardioplegic solution, and Group 6 received an oxygenated perfluorocarbon cardioplegic solution. With results expressed as the percent of infarcted myocardium within the region at risk, Group 2 hearts, which received only antegrade cardioplegia, had a mean infarct size of 44.8 +/- 6.3%, a 2.2-fold increase over controls (p less than 0.05). While antegrade delivery of oxygenated perfluorocarbon cardioplegia (Group 3) and coronary sinus perfusion with nonoxygenated crystalloid cardioplegia (Group 4) limited infarct size to 33.6 +/- 4.7% and 35.3 +/- 5.4%, respectively, only oxygenated cardioplegia delivered retrograde through the coronary sinus (Groups 5 and 6) completely prevented infarct extension during global ischemic arrest.(ABSTRACT TRUNCATED AT 250 WORDS)     

Retrograde cardioplegia via the coronary sinus

The coronary sinus, collecting about 70% of the venous blood draining the myocardium lends itself particularly well to retrograde concepts of cardioplegia. It has been gaining wide acceptance as a safe means of access to the myocardium in the presence of atherosclerotic disease and as an important modality in providing a more homogeneous distribution of cardioplegic delivery. This article attempts to review all knowledge available on the pathophysiology of retroinfusion of cardioplegia as well as the state of the art of the technique involved. A new concept is being presented, which, in the form of antegrade delivery with postcapillary redistribution, this achieved either by pressure elevation of the venous effluent or pressure-controlled intermittent coronary sinus occlusion (PICSO), takes advantage of both antegrade and retrograde concepts. First experimental results suggest great potential for this combined approach in the effective delivery of cardioplegia.     

Comparison of retrograde vs simultaneous ante/retrograde cold blood cardioplegia

BACKGROUND: To evaluate the homeostasis of myocardium during simultaneous continuous retrograde and antegrade cardioplegia vs retrograde continuous cardioplegia. METHODS: 40 patients who underwent elective operation of coronary arteries bypass grafting were randomly assigned to 2 groups: group one consisted of 24 patients who received retrograde continuous blood cardioplegia; group two consisted of 16 patients who received simultaneous continuous ante/retrograde cardioplegia. The following measurements were taken: acidosis, oxygen content, oxygen extraction and oxygen consumption; they were taken before and after cross-clamp releasing from coronary sinus effluent and from arterial line. Incidence of low cardiac output, ventricular fibrillation, raised cardiac enzymes and ischemic changes on ECG was noted. RESULTS: In simultaneous group such parameters as acidosis, oxygen content, oxygen extraction and myocardial oxygen consumption recovered after cross-clamping and changes of their values were respectively: 0.0005, 0.87 ml/100 ml, 0.098 and 1.4 ml/min. The same parameters didn't recovered in retrograde group and changes were respectively: 0.05 - p=0.2; 3.7 ml/100 ml - p=0.006, 0.29 p=0.006 and 7.4 ml/min - p=0.03. These changes were significant between groups. CONCLUSIONS: Metabolic viability of myocardium measured with oxygen utilisation is better preserved with simultaneous antegrade and retrograde cardioplegia.     

The Influence of Collateral Flow on the Antegrade and Retrograde Distribution of Cardioplegia in Patients with an Occluded Right Coronary Artery

Background: The predictive value of electrocardiography (ECG) and coronary angiography for cardioplegia distribution in patients with an occluded right coronary artery was evaluated.

Methods: Coronary angiograms and ECGs were evaluated in 15 patients with right coronary artery occlusion. Prediction of antegrade cardioplegia distribution was based on ECG evidence of infarction and coronary collateral flow determined from the angiogram. Antegrade and retrograde delivery of cardioplegia was directly assessed in all patients by myocardial contrast echocardiography. Intraoperative transesophageal echocardiographic images of the right ventricular free wall, the apex, and the intraventricular septum were recorded while 4 ml of Albunex (Mallinckrodt Medical, St. Louis, MO) was injected into antegrade and retrograde cardioplegic catheters during cardioplegia delivery. The observed (myocardial contrast echocardiography) cardioplegia distribution was compared to the predicted cardioplegia distribution. Sensitivity, specificity, positive predictive values, and negative predictive values were calculated.

Results: Eighty seven of 90 (97%) segments were analyzed. Angiography and ECG poorly predicted incomplete cardioplegia distribution. Electrocardiography was a better predictor of inadequate cardioplegia distribution to the right ventricle than was angiography. The negative predicted values of cardioplegia distribution ranged from 20 to 50% for the septum and right ventricle, respectively, with ECG criteria and from 0 to 33% for the septum and apex, respectively, with angiographic criteria. Antegrade cardioplegia delivery was distributed to the right ventricle in 31% of patients, despite 100% occlusion of the right coronary artery; whereas retrograde cardioplegia delivery to the right ventricle occurred 20% of the time.