Coronary artery bypass surgery for chronic total occlusion of the left main coronary artery by means of intermittent antegrade cold blood cardioplegia

From January, 1984 to May, 1990 eleven patients (men 9, women 2) underwent coronary artery bypass surgery for chronic total occlusion of the left main coronary artery by means of intermittent antegrade cold blood cardioplegia. The ages ranged from 33 to 74 (mean 56) years. The causes of the total occlusion of the left main coronary artery were atherosclerosis in 10 patients and aortitis syndrome in one. Four patients had history of a previous myocardial infarction. Preoperative selective coronary arteriography revealed well developed collateral vessels from the RCA to the LCA in all patients. One to five coronary arteries were bypassed. Myocardial protection was obtained in the usual fashion: antegrade intermittent cold blood cardioplegia with topical cardiac cooling. All patients were successfully weaned off from cardiopulmonary bypass without the need of IABP assist. No patient developed perioperative myocardial infarction. All grafts were patent postoperatively. Treadmill testing was negative in all patients. We believe that coronary artery bypass surgery for chronic total occlusion of the left main coronary artery can be performed safely with intermittent antegrade cold blood cardioplegia.     

The dynamics of antegrade cardioplegia with simultaneous coronary sinus occlusion. Effects on aortic root infusion pressure, coronary sinus pressure, and myocardial cooling

It has been suggested that antegrade cardioplegia with coronary sinus occlusion improves homogeneous myocardial cooling and reduces myocardial injury in the presence of coronary artery occlusion. Little data are available on the exact relationships among the basic elements or this intervention, including antegrade infusion rate, aortic root pressure, the degree of coronary sinus occlusion, coronary sinus pressure, and myocardial cooling. The purpose of this study was to determine these relationships and to provide some basic guidelines for better understanding of this intervention. Twenty-two sheep were placed on cardiopulmonary bypass, the distal left anterior descending artery was occluded, and the proximal coronary sinus was snared. Sixteen combinations of infusion rate (3, 5, 7, or 9 ml/kg/min) and coronary sinus occlusion (total, subtotal, or moderate occlusion or no occlusion) were adopted for each 2 minutes of antegrade cardioplegia, yielding 96 measurements. Myocardial temperatures in the occluded and nonoccluded regions, aortic root infusion pressure, and coronary sinus pressure were measured during each infusion of cardioplegic solution. Coronary sinus occlusion was then released, and the whole heart was reperfused for 30 minutes for another infusion of cardioplegic solution and measurements. Results showed good degrees of linearity between infusion rate and aortic root infusion pressure for all coronary sinus occlusion and noninfusion groups (p less than 0.01). A positive effect of coronary sinus occlusion on aortic root infusion pressure was observed. The graded increases in infusion rate with various degrees of coronary sinus occlusion were constantly associated with elevation of coronary sinus pressure (p less than 0.01). It was also noted that myocardial temperatures in the region of the occluded left anterior descending artery were significantly lower in coronary sinus occlusion groups than in nonocclusion groups (p less than 0.01 or 0.05). Myocardial temperature in the nonoccluded region decreased significantly with the stepwise increases in infusion rate (p less than 0.01), but not with the increases in coronary sinus occlusion (not significant). Based on this and previous studies, we recommend that the induced coronary sinus pressure be safely maintained in the range of 25 to 35 mm Hg and that further studies be focused on the infusion rate of 5 ml/kg/min with subtotal or total coronary sinus occlusion for the intervention of antegrade cardioplegia plus coronary sinus occlusion.     

The Effect of Acute Coronary Artery Occlusion during Cardioplegic Arrest and Reperfusion on Myocardial Preservation

A study was undertaken to evaluate the effect of acute occlusion of a coronary artery during cardioplegic arrest on myocardial preservation and to elucidate the influence of reestablishment of flow versus continued occlusion during the phase of myocardial reperfusion. Coronary occlusion was simulated, and myocardial viability was determined by measuring tissue levels of adenosine triphosphate (ATP) and creatine phosphate (CP) in biopsies of the posterior left ventricular wall. Eighteen pigs were divided into three equal groups consisting of animals with (1) patent right coronary arteries during arrest and reperfusion, (2) occluded right coronary arteries during arrest and patent during reperfusion, and (3) occluded right coronary arteries during arrest and reperfusion.The results of ATP and CP measurements showed that while poorer protection was afforded during two-hour arrest when the coronary artery was occluded, the risk of damage was much greater during reperfusion. Failure to restore adequate blood flow by retention of occlusion caused a concurrent decrease in ATP and CP levels below prescribed limits of myocardial tolerance. When occlusion occurs in the clinical setting, impeding cardioplegia and reperfusion, the importance of revascularization is emphasized.     

Effect on myocardial perfusion of simultaneous delivery of cardioplegic solution through a single coronary artery and the coronary sinus.

OBJECTIVE: This study was to determine whether simultaneous antegrade-retrograde cardioplegia through a single coronary artery and the coronary sinus provides sufficient and homogeneous perfusion to the heart. METHODS: Simultaneous antegrade-retrograde cardioplegia was conducted in 7 isolated pig hearts through the coronary sinus in conjunction with the left anterior descending artery, the left circumflex artery, and the right coronary artery, respectively. The efficacy of simultaneous antegrade-retrograde cardioplegia for myocardial perfusion was assessed by monitoring the distribution of magnetic resonance contrast agent and measuring the effluent from the venting coronary arteries. RESULTS: Injection of contrast agent into a perfusing artery during simultaneous antegrade-retrograde cardioplegia resulted in increased image signal intensity not only in the territory of the perfusing artery but also in the areas normally served by the other 2 venting arteries (including the right ventricular wall). The myocardium in the territories of the 2 venting arteries was lightened with contrast agent given into the coronary sinus during simultaneous antegrade-retrograde cardioplegia. Myocardium in the perfusing artery territory and right ventricular wall remained dark. Moreover, a significant amount of effluent was collected from the venting arteries during simultaneous antegrade-retrograde cardioplegia: 4.7 to 7.8 mL/min from the right coronary artery; 10.5 to 17.7 mL/min from the left anterior descending artery; and 9.7 to 15.2 mL/min from the left circumflex coronary artery. CONCLUSIONS: Simultaneous antegrade-retrograde cardioplegia through a single coronary artery and the coronary sinus provides homogeneous perfusion to the entire heart. During simultaneous antegrade-retrograde cardioplegia, arterial flow supports its own designated myocardium, as well as adjacent myocardium normally served by the venting arteries; the arterial route also supports the right ventricular free wall when the right coronary artery is vented. Venous perfusion of simultaneous antegrade-retrograde cardioplegia mainly supports myocardium in the territories of the venting arteries and does not perfuse the right ventricular free wall. Blood flow delivered to myocardium normally supported by the venting arteries is believed to be sufficient to prevent ischemic injury.     

Surgical treatment of right coronary arteries with anomalous origin and slit ostium

BACKGROUND: Right coronary arteries arising in the left sinus or ectopically in the anterior coronary sinus with slit ostium course inside the aorta. They are subject to variable systolic compression and can cause myocardial ischemia with its sequelae or death. METHODS: From May 1991 to March 2003, we treated 16 patients with anomalous origin of the right coronary artery from the left sinus and 4 whose right coronary artery arose ectopically in the anterior sinus. All patients had a slit ostium and underwent transaortic unroofing of the trunk to modify the proximal portion of the anomalous artery. RESULTS: All patients survived operation, although 1 patient died of unrelated causes. Nineteen patients were followed for a period from 0.2 to 11.8 years (median age, 53 years). One experienced angina 1 year after surgery and underwent percutaneous transluminal coronary angioplasty of a left internal thoracic to left anterior descending coronary artery anastomosis. All patients are New York Heart Association class I, without angina; none has sustained a myocardial infarction or required reoperation. CONCLUSIONS: Right coronary arteries that arise in anomalous fashion with a slit ostium can cause myocardial ischemia or death. Transaortic modification of the anomalous trunk addresses the anatomic and pathophysiologic features of the malformation that cause myocardial ischemia. Excellent results can be achieved with this surgical approach.     

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.     

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.     

Studies of retrograde cardioplegia. I. Capillary blood flow distribution to myocardium supplied by open and occluded arteries

This study defines the nutritive (i.e., capillary) distribution of blood cardioplegic solutions delivered via retrograde and antegrade techniques to muscle supplied by open and occluded coronary arteries where myocardial segments are in jeopardy of inadequate cardioplegic protection. Open-chest anesthetized dogs were studied by mixing radioactive microspheres (15 +/- 5 microns) with a blood cardioplegic solution and administering cardioplegia either into the coronary sinus or into the proximal aorta with the left anterior descending coronary artery open or occluded (30% +/- 2% area at risk). Nutritive flow (i.e., percentage of delivered 15 microns microspheres trapped in myocardial capillaries) during retrograde infusions averaged 65% versus 87% with antegrade cardioplegia (p less than 0.05). Retrograde and antegrade cardioplegic nutritive flow to all left ventricular regions was comparable with the left anterior descending coronary artery open (65 versus 82 ml/100 gm/min, p greater than 0.05), and both methods provided preferential hyperperfusion of subendocardial muscle (endocardial/epicardial ratios 1.6 and 1.5, respectively). Nutritive flow to muscle supplied by the occluded left anterior descending coronary artery was preserved better by retrograde than antegrade cardioplegia (35 versus 5 ml/100 gm/min, p less than 0.05). Preferential subendocardial hyperperfusion was maintained during retrograde cardioplegia (52 ml/100 gm/min, endocardial/epicardial ratio 1.6), but flow was redistributed away from subendocardial muscle with antegrade cardioplegia (less than 2 ml/100 gm/min, endocardial/epicardial, 0.29, p less than 0.05). Left ventricular flow was reduced markedly during retrograde infusion with the left anterior descending coronary artery open or occluded (23 and 12 ml/100 gm/min), but septal cooling was superior to antegrade cardioplegia (15 degrees +/- 1 degree C versus 20% +/- 3%, p less than 0.05) despite near-normal antegrade septal flow (the left anterior descending coronary artery was ligated beyond the first septal branch). Right ventricular nutritive flow was only 7 ml/100 gm/min during retrograde coronary sinus perfusion and was maintained normally with antegrade cardioplegia.(ABSTRACT TRUNCATED AT 400 WORDS)     

Influence of coronary anatomy and reimplantation on the long-term outcome of the arterial switch.

BACKGROUND: Abnormal coronary artery anatomy is reported to have a significant influence on the outcome of the arterial switch operation. This study examines the impact of coronary anatomy and the occurrence of late coronary obstruction on left ventricular (LV) function and long-term outcome. METHODS: Coronary artery anatomy, of 170 patients after arterial switch operation (1977-1999), was determined based on operative reports and pre-operative aortograms. Current status was evaluated using ECGs, echocardiograms, scintigraphy, and post-operative coronary angiograms. RESULTS: In 133/170 patients, coronary artery anatomy consisted of an anterior descending (LAD) and circumflex artery (Cx) from the left sinus and the right coronary artery (RCA) from the right or posterior sinus. The left coronary had an intramural initial course in two of these patients. Fifteen patients had the LAD from the left and Cx and RCA from the right sinus; eight had LAD and RCA from one sinus and Cx from the other; four had single ostium; and three had three separate ostia. Four patients had complex patterns and four patients had a supra commissural coronary. To date, follow-up angiography was performed in 59 patients. Surgical coronary sequellae were found in five patients. Two patients had an occluded left ostium. Initially, they were asymptomatic but showed polymorphic ventricular extrasystoles on ECG and moderate LV dysfunction with large irreversible perfusion defects on scintigraphy. Both patients developed ventricular fibrillation at the age of 14 years. One patient did not survive. The other patient required implantation of a defibrillator. One patient has an occluded RCA, one patient has stenosis of the right ostium and one patient has multiple tortuous collaterals without obstruction of a major branch. In the latter three patients, coronary sequellae were not suspected on ECG, echo, or scintigraphy and were only found on follow-up angiography. Retrograde collateral flow was noted in all three occluded coronaries. LV dysfunction, with normal coronaries, was noted in three patients. All, of these patients, had peri-operative ischaemia suggesting failure of myocardial protection. Two are now asymptomatic with mild LV dysfunction. One patient continues to have severe myocardial dysfunction and secondary aortic insufficiency. A Ross-like procedure was performed placing the original aortic valve in the neo-aortic root. Coronary artery anatomy did not influence early survival or late coronary sequellae. CONCLUSION: Abnormal coronary anatomy was not a determinant of outcome in our study. Surgical coronary obstruction is independent of original anatomy. It can be almost silent and is potentially fatal. Follow-up angiography must be considered in all patients after the arterial switch operation.     

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)     

Coronary Artery Stenosis Following Aortic Valve Replacement and Intermittent Intracoronary Cardioplegia

From July, 1977, to July, 1980, intermittent cold blood potassium cardioplegia was used in 208 patients undergoing aortic valve replacement. Aortic root injection of the cardioplegic solution at 10°C was followed every 20 to 30 minutes by infusions of the solution through Silastic cannulas sutured in the coronary orifices or reinserted with each injection.Symptoms of myocardial ischemia developed in 6 patients 3 to 30 months postoperatively. Coronary angiography confirmed new stenoses of the left orifice (3 patients), left main trunk (1 patient), left anterior descending coronary artery (2 patients), circumflex coronary artery (1 patient), and right orifice (3 patients). Four patients underwent saphenous vein grafting procedures, with 2 deaths; 2 patients refused reoperation. A seventh patient with 80% stenosis of the circumflex coronary artery and a posterolateral myocardial infarction died 2 months after double-valve replacement.Intermittent cold blood potassium cardioplegia instead of continuous perfusion did not prevent coronary arterial injury. Injuries occurred in the distal coronary arteries as well as the orifices and were not prevented by withdrawal of the cannulas between injections. Tight-fitting cannulas and high-pressure injection should be avoided. A careful search for coronary arterial injury should be made in all symptomatic patients following aortic valve replacement.     

A comparison of retrograde cardioplegia versus antegrade cardioplegia in the presence of coronary artery obstruction

Cardioplegic protection is limited by nonhomogeneous distribution of solutions distal to coronary artery obstructions. Using temperature mapping and sonomicrometry crystals implanted in the distributions of the left anterior descending (LAD) and circumflex coronary arteries, we studied the effects of blood cardioplegia delivery through the aortic root versus the coronary sinus in 10 dogs with a temporarily occluded LAD. All dogs were placed on cardiopulmonary bypass and cooled to 28 degrees C; the aorta was cross-clamped for two hours with the LAD occluded. Group 1 (N = 5) had cold (4 degrees C) potassium chloride cardioplegia (20 mEq per liter of KCl) administered through the aortic root at 20-minute intervals; Group 2 (N = 5) had the same solution infused through the coronary sinus by a balloon catheter. After two hours, the LAD snare was released and the dogs were weaned from bypass. Aortic root cardioplegia resulted in very poor cooling distal to the coronary obstruction with very poor systolic function and loss of diastolic compliance. In contrast, coronary sinus cardioplegia resulted in normal cooling distal to the coronary obstruction and complete return of systolic and diastolic functions following the experimental procedure. We conclude that cardioplegia administered through the coronary sinus offers superior cooling distal to coronary artery obstructions while preserving myocardial function in all areas. In contrast, delivery of cardioplegia through the aortic root causes severe depression in the myocardium distal to obstructions.     

Clinical study on the use of retrograde cardioplegia with St. Thomas' Hospital solution

One hundred and three consecutive patients with aortic valve disease and twenty seven patients with ischemic heart disease of severe critical coronary stenosis or left main trunk stenosis underwent open heart operations with the use of retrograde cardioplegic technique for myocardial protection. Under complete cardiopulmonary bypass, a balloon catheter was inserted into the coronary sinus through small right atriotomy and secured in place. Retrograde cardioplegia was accomplished using cold St. Thomas' Hospital solution by drip method at height of 60 to 80 cm with topical saline slush. Cardiac resuscitation was very easy and acceptable hemodynamics were obtained in all patients. Even in 8 patients in which aortic crossclamping time was above 180 minutes cardiac recovery was excellent except one who needed IABP support. Eight patients in aortotomy group were died postoperatively from the reasons unrelated to myocardial protection. Postoperative hemodynamic data and enzymatic analyses of CK-MB revealed good myocardial protective effects. Retrograde cardioplegia with the use of cold St. Thomas' Hospital solution is thus an effective alternative of myocardial protection in aortic valve surgery or aortotomy surgery and in coronary revascularization for multiple coronary stenoses or left main trunk lesions.     

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.     

Nonsyphilitic coronary ostial stenosis.

From October 1970 to June 1977, a total of 15 patients (12 women) were seen with atherosclerotic coronary ostial stenosis (14 left, one right). All patients had angina and two had aortic valve disease. Additional coronary arterial disease was present in nine. One patient declined surgery and died four months later after myocardial infarction. All patients had coronary bypass grafts and two had aortic valve replacement. One patient with valve replacement and one with preoperative cardiogenic shock died postoperatively. Angina recurred nine months postoperatively in one patient; the others (11) are free of angina. Postoperative catheterization from two weeks to 4.5 years in ten of 12 showed 11 of 13 vein grafts and eight of nine internal mammary artery grafts to be patent. In three patients, only a single left-sided coronary bypass was placed to the left anterior descending artery, because the circumflex branches were too small. Ideally, two left-sided bypass grafts should be placed for left ostial disease.     

Robotic totally endoscopic coronary artery bypass and catheter based coronary intervention in one operative session

A 56-year-old male patient underwent robotically assisted totally endoscopic left internal mammary artery (LIMA) to left anterior descending artery (LAD) grafting. After protamine administration complete heart block developed in the patient. On intraoperative angiography the LIMA to LAD graft was perfectly patent but an acute occlusion of the right coronary artery (RCA) was noted. We performed an immediate on table percutaneous coronary angioplasty and stent placement to the RCA. The heart regained sinus rhythm and the wall motion abnormalities on the back wall of the heart resolved. No clinical symptoms indicating ongoing myocardial ischemia were noted postoperatively. This case demonstrates that a hybrid procedure of robotic totally endoscopic coronary artery bypass grafting and catheter based coronary intervention is feasible in one simultaneous session.     

Surgical management of penetrating injuries to the coronary arteries.

Among 76 patients with heart wounds treated over a 4 year period, nine had penetrating injuries to the coronary arteries with clinical presentations of pericardial tamponade, electrocardiographic abnormalities of bundle branch block or ST and T wave changes, and hemothorax. The right coronary artery was injured in two patients, the left anterior descending coronary artery in six patients, and the left circumflex coronary artery in one patient. All but one of these injured coronary arteries were treated by ligation. One patient with a proximal left anterior descending coronary artery transection presented with cardiac arrest and was managed successfully by emergency cardiopulmonary support and saphenous vein bypass with ligation of the transected ends of the artery. The only death occurred six days postoperatively in a patient with a right coronary artery laceration and was not related to the heart injury. No late symptomatic or hemodynamic sequelae have been noted among any of these patients. Principles of elective cardiac surgery are readily adaptable to the patient with a coronary artery injury.     

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.     

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.     

Reversal of reperfusion injury after ischemic arrest with pressure-controlled intermittent coronary sinus occlusion

Recent experimental studies have shown that pressure-controlled intermittent coronary sinus occlusion effectively reduces both infarct size and myocardium at risk after coronary artery occlusion. This study was undertaken to determine whether this modality was equally effective in altering reperfusion damage after a period of ischemic arrest. Fourteen pigs were placed on cardiopulmonary bypass and subjected to 2 hours of ischemic arrest with multidose potassium crystalloid cardioplegia supplemented with topical and systemic hypothermia (28 degrees C). During arrest, the mid-left anterior descending artery was occluded with a snare, which was released immediately after aortic unclamping. In seven pigs, a 7F balloon-tipped catheter was positioned in the coronary sinus and pressure-controlled intermittent coronary sinus occlusion was performed for 60 minutes after aortic unclamping. Seven other pigs served as controls. Parameters measured included stroke work index, ejection fraction, and myocardial pH in the distribution of the distal left anterior descending artery. Pigs treated with pressure-controlled intermittent coronary sinus occlusion had a significantly higher myocardial pH (6.99 +/- 0.06 versus 6.67 +/- 0.05, p less than 0.01), ejection fraction (50% +/- 2% versus 33% +/- 6%, p less than 0.01), and stroke work index (0.87 +/- 0.07 versus 0.61 +/- 0.05 gm-m/kg, p less than 0.01) after 60 minutes of reperfusion compared with those of the group not treated in this way. We conclude that pressure-controlled intermittent coronary sinus occlusion effectively reverses reperfusion damage after periods of ischemic arrest.