Elective minimally invasive coronary artery bypass: Shunt or tournique occlusion? Assessment of a protective role of perioperative left anterior descending shunting on myocardial damage. A prospective randomized study

ABSTRACT: BACKGROUND: To determine impact of intraluminal-left anterior descending shunt to prevent myocardial damage in minimally invasive coronary artery bypass. METHODS: 38 patients were randomly assigned to external tournique occlusion (n = 19) or intraluminal-left anterior descending shunt group (n = 19). Blood samples for cardiac troponin T were collected at 30 minutes prior to, 6 and 24 hours after surgery. RESULTS: One patient in external tournique occlusion and two patients in intraluminal-left anterior descending shunt group were excluded from futher analysis due to preoperative cardiac troponin T level above the 99th-percentile. Postoperatively, each six patients in external tournique occlusion (33.3%) and intraluminal-left anterior descending shunt (35.3 %) group were above the 99th-percentile. Two patients from each group (external tournique occlusion group 11.1 % vs. intraluminal-left anterior descending shunt group 11.8 %) had peak values above 10-% coeficient of variation cutoff (p = 1). There were no significant differences in between both groups at all studied timepoints. CONCLUSION: There was no protective effect of intraluminal shunting on myocardial damage compared to tournique occlusion. It is upon the surgeon's discretion which method may preferrably be used to achieve a bloodless field in grafting of the non-occluded left anterior descending in minimally invasive coronary artery bypass.     

Sevoflurane but not propofol preserves myocardial function during minimally invasive direct coronary artery bypass surgery

Volatile anesthetics exert cardioprotective properties in experimental and clinical studies. We designed this study to investigate the effects of sevoflurane on left ventricular (LV) performance during minimally invasive direct coronary artery bypass grafting (MIDCAB) without cardiopulmonary bypass. Fifty-two patients scheduled for MIDCAB surgery were randomly assigned to a propofol or a sevoflurane group. Apart from the anesthetics used, there was no difference in surgical and anesthetic management. After determination of cardiac troponin T, creatine kinase, and creatine kinase MB, electrocardiographic (ECG) data and echocardiography variables (myocardial performance index and early to atrial filling velocity ratio) the left anterior descending coronary artery (LAD) was clamped until anastomosis with the left internal mammary artery was completed. During LAD occlusion and during reperfusion, echocardiography measurements were repeated. Blood samples were obtained repeatedly for up to 72 h. After LAD occlusion, myocardial performance index and early to atrial filling velocity ratio in the propofol group deteriorated significantly from 0.40 +/- 0.12 and 1.29 +/- 0.35 to 0.49 +/- 0.10 and 1.13 +/- 0.22, respectively, whereas there was no change in the sevoflurane group. In the propofol group myocardial performance index remained increased (0.47 +/- 0.11) compared with baseline during reperfusion. There were no significant differences in ECG and laboratory values between groups. In conclusion, during a brief period of ischemia in patients undergoing MIDCAB surgery, sevoflurane preserved myocardial function better than propofol.     

Experimental off-pump coronary artery revascularization with adenosine-enhanced reperfusion

OBJECTIVE: Although beating heart coronary artery bypass grafting has recently gained popularity, it eliminates the protective strategies (ie, cardioplegia) developed for use in conventional cardiac operations. We recently introduced the technique of perfusion-assisted direct coronary artery bypass to perfuse the grafted vessels during multivessel off-pump coronary artery bypass grafting. In the present study we tested the hypothesis that intracoronary reperfusion with the cardioprotective agent adenosine during simulated perfusion-assisted direct coronary artery bypass attenuates reperfusion injury. METHODS: In anesthetized dogs the heart was exposed, and the left anterior descending coronary artery was ligated for 75 minutes. Reperfusion was achieved through a catheter in the left anterior descending coronary artery by means of a computer-controlled pump. Intracoronary left anterior descending coronary artery perfusion pressure was continuously matched to mean arterial blood pressure. In one group (adenosine group) 10 micromol/L adenosine was added to the blood during the first 30 minutes of reperfusion, whereas another group (vehicle group) received a comparable volume of saline solution. RESULTS: During the first 30 minutes of reperfusion, blood flow through the left anterior descending coronary artery was significantly greater (P <.05) in the adenosine group than in the vehicle group (150.6 +/- 21.9 vs 50.2 +/- 11.3 mL/min at 15 minutes of reperfusion). Although there were no group differences in postischemic wall motion, infarct size was significantly smaller in the adenosine group than in the vehicle group (11.1% +/- 3.0% vs. 28.0% +/- 4.0% of area at risk, P <.05). Myeloperoxidase activity in the necrotic tissue, an index of neutrophil accumulation, tended to be lower in the adenosine group than in the vehicle group (58.6 +/- 14.2 vs. 91.0 +/- 21.6 DeltaAbs Units x min(-1) x g(-1) tissue). In isolated postischemic left anterior descending coronary artery rings, the maximal relaxation response to the endothelium-dependent vasodilator acetylcholine was significantly greater in the adenosine group than in the vehicle group (97.9% +/- 5.6% vs. 64.7% +/- 6.5%, P<.05). CONCLUSION: This novel reperfusion strategy for off-pump coronary artery bypass grafting can be used not only in cases requiring multiple grafting but also to attenuate necrosis and endothelial dysfunction in acute evolving infarction.     

Minimally invasive direct coronary artery bypass in a cardiac transplant recipient with allograft vasculopathy

Coronary bypass operation with cardiopulmonary bypass has provided disappointing results for the treatment of cardiac allograft vasculopathy (CAV). We describe a 61-year-old man who underwent heart transplantation for secondary dilated cardiomyopathy in 1995. Consecutively, CAV developed with clinically silent left anterior descending occlusion. After angiographic diagnosis in 1998 he successfully underwent a minimally invasive direct coronary artery bypass procedure. Annual coronary angiography showed a patent left internal mammary to left anterior descending bypass graft more than 4 years after operation. In select cases, minimally invasive direct coronary artery bypass is a therapeutic option for the treatment of CAV.     

Controlled reperfusion following regional ischemia

The ability to reverse acute coronary occlusion with fibrinolytic agents and percutaneous transluminal angioplasty has increased interest in the revascularization of ischemic myocardium. This study defines changes in global ventricular function, mass, and compliance during acute coronary occlusion and following reperfusion with blood in the beating and arrested heart. In 17 dogs on cardiopulmonary bypass, the proximal left anterior descending coronary artery was occluded for 45 minutes. In 12 dogs, flow was reestablished by releasing the coronary snare in the beating heart. In the other 5 dogs, the snare was released during a continuous 10-minute infusion of blood potassium cardioplegia in the arrested heart. Coronary occlusion resulted in significant decreases in stroke work index and left ventricular (LV) mass, but compliance was unchanged. Reperfusion in the beating heart increased LV mass compared with the values measured before ischemia (104 +/- 5 versus 95 +/- 5 gm; p less than 0.05) and decreased LV compliance (39 +/- 4 versus 53 +/- 4 ml at LV end-diastolic pressure of 8 mm Hg; p less than 0.05). In contrast, with blood cardioplegia-based reperfusion in the arrested heart, LV mass and LV compliance remained unchanged from control values. We conclude that revascularization of acutely ischemic myocardium in the beating heart further impairs LV function by increasing LV mass and decreasing compliance. This damage can be avoided by reperfusion with blood cardioplegia in the arrested heart.     

Effects of antegrade cardioplegic infusion with simultaneously controlled coronary sinus occlusion on preservation of regionally ischemic myocardium after acute coronary artery occlusion and reperfusion

This study was conducted to assess the protective effects of antegrade infusion of cardioplegic solution with simultaneously controlled coronary sinus occlusion on regionally ischemic myocardium after acute coronary occlusion and reperfusion. Twelve sheep were subjected to 1 hour of occlusion of the distal left anterior descending coronary artery. Sheep in group I (n = 6) were subjected only to infusion of potassium crystalloid cardioplegic solution into the aortic root, whereas in group II (n = 6) a stitch was snared around the proximal coronary sinus for its subsequent occlusion during antegrade infusions of cardioplegic solution. All animals were placed on cardiopulmonary bypass. Five hundred milliliters of cardioplegic solution at 4 degrees to 8 degrees C was administered in three divided doses during the total cross-clamp period of 30 minutes. The occlusion of the left anterior descending artery was then released, and the animals were weaned from bypass and studied for an additional 4 hours. Coronary sinus pressure, myocardial temperature, regional function assessed by pairs of ultrasonic crystals, global function assessed by rate of rise of left ventricular pressure and cardiac output, and the area at risk and area of necrosis were determined. The heart was excised at the end of the experiment and stained. Animals treated by the technique of antegrade infusion combined with coronary sinus occlusion had more homogeneous myocardial cooling during cardioplegic infusions and better recovery of the first derivative of left ventricular pressure and regional segment shortening at 90 and 270 minutes of reperfusion than those treated with antegrade infusion alone (p less than 0.01 and p less than 0.05, respectively). The group treated by antegrade infusion of cardioplegic solution combined with coronary sinus occlusion had an area of necrosis/area at risk ratio of 40.5% +/- 1.2%; the antegrade infusion group, 58.3% +/- 4.1% (p less than 0.01). These data suggest that antegrade infusion combined with coronary sinus occlusion may be an improved method of global and regional myocardial protection in the presence of an occluded coronary artery.     

Myocardial protection with high-dose beta-blockade in acute myocardial ischemia.

OBJECTIVE: The risk of postoperative cardiac dysfunction is markedly increased by emergency coronary artery bypass grafting in the presence of acute myocardial ischemia. High dose beta-blockade during continuous coronary perfusion has been suggested as an alternative to conventional cardioplegia and this technique has been applied successfully in high risk patients for coronary artery bypass grafting (CABG) surgery. This study compared high dose beta-blockade with esmolol to continuous warm blood cardioplegia in a clinically oriented model of acute left ventricular (LV) ischemia and reperfusion. METHODS: Twelve dogs were subjected to 60 min of regional LV ischemia by left anterior descending branch (LAD) ligation. Cardiopulmonary bypass (CPB) and aortic crossclamp were applied after 45 min of ischemia. Thereafter, high dose beta-blockade during continuous coronary perfusion (ESMO, n = 6) or antegrade continuous warm blood cardioplegia (WBC, n = 6) were maintained for 60 min. Myocardial water content (measured from endomyocardial biopsies using a microgravimetric technique), global LV function (preload recruitable stroke work: PRSW), and regional LV function (echocardiographic wall motion score) were determined at baseline and after weaning from CPB. RESULTS: During aortic crossclamp interstitial edema formation was significantly higher in the WBC group with an average water gain of 2.2 +/- 0.49 vs. 0.76 +/- 0.12% in the ESMO group. Thereafter, edema resolved in both groups, but myocardial water gain remained significantly higher in the WBC group at 60 and 120 min post CPB (0.98 +/- 0.19 and 1.13 +/- 0.32% vs. 0.07 +/- 0.25 and 0.04 +/- 0.08%). Global LV function was significantly higher in the ESMO group at 60 and 120 min post CPB (PRSW 103 +/- 6 and 94.7 +/- 4.6% of baseline vs. 85.3 +/- 4.9 and 74.7 +/- 7.6% of baseline). However, regional LV function showed no significant difference between groups. CONCLUSIONS: High-dose beta-blockade during continuous coronary perfusion may allow the surgeon to utilize the advantages of warm heart surgery, while avoiding the interstitial edema formation and temporary cardiac dysfunction associated with continuous warm blood cardioplegia. In high risk patients such as patients with unstable angina or after failed PTCA, high-dose beta-blockade may be an applicable alternative to cardioplegic arrest.     

Effects of diltiazem cardioplegia on global function, segmental contractility, and the area of necrosis after acute coronary artery occlusion and surgical reperfusion

We investigated the effects of diltiazem cardioplegia on myocardial function and infarct size in the region of the left anterior descending artery after acute occlusion and reperfusion during cardiopulmonary bypass. Sheep (30 kg) were subjected to 1 hour of regional myocardial ischemia by occlusion of the left anterior descending artery and assigned to a control (n = 8) or experimental group (n = 5). Control animals were placed on cardiopulmonary bypass and the heart arrested with potassium cardioplegia. The left anterior descending artery was released and two additional doses of 100 ml of cardioplegic solution were infused during the total cross-clamp time of 30 minutes. The animals were then weaned from bypass after 1 hour and beating, working reperfusion maintained for an additional 4 hours. The experimental group followed the same protocol except that the cardioplegic solution contained diltiazem (1.4 mg/L). Segmental myocardial function was determined by pairs of ultrasonic crystals in the area at risk, control segment, and minor axis. Global contractility was determined from maximum derivative of left ventricular pressure and cardiac output. The area at risk was determined by injecting monastral blue dye into the left atrium with the left anterior descending artery briefly reoccluded, and the area of necrosis was determined by measuring with a planimeter non-triphenyltetrazolium chloride stained areas in the sectioned left ventricle. After 5 hours of reperfusion, not only did the diltiazem group demonstrate better global contractility as defined by the derivative of left ventricular pressure (1853 +/- 292 versus 979 +/- 191, p = 0.05) but, in addition, the systolic shortening in the ischemic area improved significantly when compared with the control group (9.4 +/- 4 versus 2.13 +/- 0.77, p = 0.05). The group receiving diltiazem cardioplegia had an area of necrosis to area at risk ratio of 31.4% +/- 3%, which was significantly better than this ratio in the control group of 60.75% +/- 7% (p = 0.01). Diltiazem cardioplegia results in improved global and segmental contractility and limits the infarct size after occlusion of the left anterior descending artery and surgical reperfusion.     

Coronary artery bypass grafting without cardiopulmonary bypass for high-risk patients

Between January 1991 and June 1993, coronary artery bypass grafting was performed without either cardiopulmonary bypass or cardiac arrest in 23 patients. Most patients had several surgical risk factors, including age ⩾ 70 years, poor left ventricular function, left main coronary artery stenosis, chronic renal failure, and aortic aneurysm. Distal anastomoses were made under temporary interruption of coronary flow. A total of 37 distal anastomoses to the left anterior descending coronary artery and/or right coronary artery (mean 1.6 per patient) were made, 24 of which were internal thoracic arteries. The coronary occlusion time ranged from 7–14 min (mean 9.8 min). Combined cardiac or vascular operations were carried out in six patients (abdominal aortic aneurysm repair, thoracic aortic aneurysm repair, carotid endarterectomy, and coronary endarterectomy). There was one hospital death. Postoperative angiography was performed in 22 patients and showed a patency rate of 89%. In summary, coronary artery bypass grafting without cardiopulmonary bypass may improve the postoperative outcome of high-risk patients.     

On-line assessment of regional ventricular wall motion by transesophageal echocardiography with color kinesis during minimally invasive coronary artery bypass grafting

OBJECTIVE: Our objective was to determine the changes in regional ventricular wall motion during minimally invasive direct coronary artery bypass grafting by color kinesis using transesophageal echocardiography. METHODS: Minimally invasive coronary artery bypass grafting was performed in 34 patients, during which transesophageal echocardiography was used. Thirteen patients had isolated disease of the left anterior descending artery. Regional ventricular wall motion was analyzed by color kinesis with the SONOS 2500 transesophageal echocardiograph (Hewlett-Packard Co, Andover, Mass). On-line assessment of regional wall motion was continued during the operation. RESULTS: Wall motion abnormalities during ischemia were present in 4 cases, left ventricular mid-anterior hypokinesis in 3 cases, and left ventricular apical-lateral hypokinesis in 1 case. In all cases, wall motion was maintained after bypass. In patients with total coronary occlusion, changes in wall motion did not occur during anastomosis. CONCLUSIONS: Color kinesis allowed us to evaluate the change in regional ventricular wall motion induced by myocardial ischemia during minimally invasive coronary artery bypass grafting both objectively and quantitatively.     

Successful combined minimally invasive direct coronary artery bypass and transapical aortic valve implantation

Transapical aortic valve implantation is indicated in high-risk patients with aortic stenosis and peripheral vascular disease requiring aortic valve replacement. Minimally invasive direct coronary artery bypass grafting is also a valid, minimally invasive option for myocardial revascularization in patients with critical stenosis on the anterior descending coronary artery. Both procedures are performed through a left minithoracotomy, without cardiopulmonary bypass, aortic cross-clamping, and cardioplegic arrest. We describe a successful combined transapical aortic valve implantation and minimally invasive direct coronary bypass in a high-risk patient with left anterior descending coronary artery occlusion and severe aortic valve stenosis.     

Intracoronary shunt prevents left ventricular function impairment during beating heart coronary revascularization.

OBJECTIVE: Beating heart coronary revascularization is becoming increasingly popular world-wide. Temporary occlusion of the coronary artery is often required in order to perform the anastomosis. An alternative method to maintain perfusion is to use an intracoronary shunt. In this study, we monitored global left ventricular function and regional wall motion in the presence or absence of a shunt using transesophageal echocardiography (TEE). METHOD: Left ventricular wall motion score index (WMSI), wall motion score (WMS) in the left anterior descending (LAD) coronary artery territory, and ejection fraction (EF%) were measured by multiplane TEE during construction of the left internal mammary artery (LIMA)-LAD coronary artery anastomosis in 40 patients undergoing revascularization with or without the use of a shunt. WMSI was assessed preoperatively, 1, 3 and 6 min during the construction of the anastomosis and after 5 min of reperfusion. WMS was assessed at 6 min during anastomosis and after 5 min of reperfusion. EF% was calculated preoperatively, 5 min into the construction of the anastomosis, and 5 min after reperfusion. RESULTS: During construction of the anastomosis, when the shunt was used, there were no changes in WMSI, WMS in the LAD territory or EF%. A significant decline in these parameters was seen in the group in which the shunt was not used, although on reperfusion all the values returned to baseline control. CONCLUSION: (i) occlusion of the LAD to perform the anastomosis results in temporary impairment in left ventricular function with complete recovery on reperfusion; (ii) the use of an intracoronary shunt presumably by maintaining myocardial perfusion prevents deterioration in ventricular function; (iii) from this data it seems therefore advisable to use an intracoronary shunt in patients with unstable angina, poor left ventricular function, or in cases in which a longer time to perform the anastomosis is anticipated.     

Cardiac performance during reperfusion improved by pretreatment with oxygen free-radical scavengers

We studied the effects of oxygen free radicals on cardiac performance during reperfusion of ischemic myocardium. The pig heart, isolated in situ, was subjected to 60 minutes of regional ischemia at normothermia by occlusion of the left anterior descending coronary artery followed by 60 minutes of hypothermic cardioplegic arrest and 60 minutes of normothermic reperfusion. The oxygen free-radical scavengers, superoxide dismutase and catalase, were administered before occlusion of the left anterior descending coronary artery in the experimental group. The generation of free radicals in the untreated group, estimated by the measurement of malondialdehyde in the perfusate, was significant during reperfusion and was associated with a corresponding increase in creatine kinase. Superoxide dismutase and catalase significantly slowed the appearance of malondialdehyde and the release of creatine kinase during reperfusion. Superoxide dismutase and catalase did not alter coronary flow and myocardial oxygen extraction or consumption during occlusion of the left anterior descending coronary artery; however, coronary flow and oxygen consumption were significantly higher (p less than 0.05) during reperfusion in hearts treated with antioxidants. Left ventricular developed pressure and its maximum first derivative were measured under isovolumic conditions. In the untreated group, left ventricular developed pressure and its maximum first derivative declined to 61.1% and 57.1% of baseline values, respectively, after 60 minutes' occlusion of the left anterior descending, and to 45% of baseline values after 15 minutes of reperfusion. The decline in left ventricular developed pressure and its maximum first derivative during reperfusion was significantly (p less than 0.05) inhibited by superoxide dismutase and catalase, but left ventricular end-diastolic pressure was not significantly altered. These results implicate oxygen-derived free radicals in the injury resulting from reperfusion of ischemic myocardium and suggest that oxygen free-radical scavengers effectively protect against such injury.     

Improvement of myocardial function by trifluoperazine, a calmodulin antagonist, after acute coronary artery occlusion and coronary revascularization

Activation of an intracellular calcium-calmodulin complex may play an important role in myocardial injury induced by ischemia and reperfusion. Trifluoperazine, a calmodulin antagonist, was used before ischemia to enhance myocardial preservation by preventing intracellular calcium accumulation. The experimental model used an isolated in situ pig heart (19 control animals and 15 trifluoperazine-treated animals) subjected to occlusion of the left anterior descending coronary artery for 60 minutes followed by 60 minutes of hypothermic potassium crystalloid cardioplegic arrest and 60 minutes of reperfusion. Myocardial segmental function measured by ultrasonic crystals showed that active systolic segment shortening was abolished in the distribution of the left anterior descending artery after 60 minutes of occlusion irrespective of the treatment, whereas that not in the distribution of the left anterior descending artery increased by about 15% in both groups of animals. Restoration of systolic segment shortening in the distribution of the left anterior descending artery 60 minutes after reperfusion was 12% and 42% of baseline levels in untreated and trifluoperazine-treated animals, respectively (p less than 0.01). This improvement in segmental function by trifluoperazine was reflected in significantly (p less than 0.05) better global myocardial contractility and compliance and in significantly (p less than 0.01) greater total coronary blood flow and myocardial oxygen consumption. Trifluoperazine also increased myocardial creatine phosphate content in the distribution of the left anterior descending artery (p less than 0.01) during reperfusion, and creatine kinase release was reduced (p less than 0.05). Our results suggest that trifluoperazine improved regional myocardial function after acute occlusion of the left anterior descending artery and reperfusion and that global cardiac performance was thereby improved. The beneficial effects of trifluoperazine may be exerted by prevention of myocardial injury associated with the calcium-calmodulin complex in ischemic and reperfused myocardium.     

Reoperative coronary artery bypass grafting using a minimally invasive direct coronary artery bypass procedure

OBJECTIVE: Reoperative coronary artery bypass grafting with cardiopulmonary bypass tends to cause a higher mortality and morbidity than the primary operation. The purpose of this study was to discuss the effectiveness and safety of a minimally invasive coronary artery bypass procedure for patients who had previously undergone coronary artery bypass surgery. METHODS: We performed redo single coronary artery bypass grafting to the left anterior descending coronary artery in 9 patients and to the right coronary artery in 3 patients using minimally invasive cardiac surgery. The graft to the left anterior descending coronary artery was taken from the left internal thoracic artery in 5 patients, the right gastroepiploic artery in 3 patients, and from the saphenous vein in the other 1 patient. The graft to the right coronary artery was from the right gastroepiploic artery in all 3 patients. RESULTS: All grafts were patent. There was no major postoperative complication and no surgical or hospital death except one late death. CONCLUSIONS: In selected patients, we could safely and completely perform coronary artery bypass re-grafting to the left descending coronary artery or right coronary artery using a minimally invasive operation.     

Complete revascularization of the left anterior descending coronary artery.

OBJECTIVE: To assess the efficacy of complete revascularization of the left anterior descending coronary artery. METHODS: To obtain such revascularization, 81 patients required the use of such complex techniques as the onlay patch technique or double bypasses during bypass grafting. RESULTS: The onlay patch technique was used in 39 (48%) and double bypasses in 42 (52%). The wall motion in all anterior segments of the left ventricle showed an improving trend postoperatively. The patency rate was 99% overall, and the bypass grafts to the left anterior descending coronary artery were all patent with flow in all left anterior descending coronary artery areas. Perioperative myocardial infarction occurred in only 1 patient (1.2%), and hospital mortality was 2.5% (2/81). Long-term results of 79 hospital survivors were as follows: the mean follow-up time was 77 months (3 to 236); the actuarial survival rate including all deaths and estimated by cardiac death was 90% and 95% at the eighth postoperative year respectively; the cardiac event free rate at the fifth and eighth postoperative year was 90% and 63% respectively. A total of 8 cardiac events were observed. Excluding 3 cardiac deaths, no cardiac events were clearly attributable to the left anterior descending coronary artery. CONCLUSIONS: Complete revascularization of the left anterior descending coronary artery using these techniques improved the anterior wall motion in the left ventricle and cardiac performance at low risk, and provided excellent long-term results.     

Coronary sinus retroperfusion during acute experimental coronary artery occlusion.

BACKGROUND: This study was planned to show the effect of retroperfusion and cardiopulmonary bypass on myocardial hemodynamic recovery. METHODS: Eighteen dogs entered this study. After, left anterior descending artery (LAD) was dissected and occluded, the animals were divided into three equal groups; Group I: retrograde coronary sinus perfusion, group II: cardiopulmonary bypass and retrograde coronary sinus perfusion, Group III: control group, left anterior descending artery occlusion only. RESULTS: In Group III, deterioration of the hemodynamic values progressed parallel with the degree of ischemic damage but in Group I, hemodynamic parameters were better because of the retrograde coronary sinus perfusion and minimally affected by the reperfusion. In Group II, at the end of the cardiopulmonary bypass minimal myocardial damage was observed. CONCLUSIONS: There is no statistical difference between Group I and II if we examine the data that was taken after reperfusion although myocardial performance was better in Group II.     

Minimally invasive port-access coronary artery bypass grafting.

The Port-Access endovascular cardiopulmonary bypass system (Heartport, Inc., Redwood City, CA, USA), a recent technological innovation in minimally invasive cardiac surgery, was conducted successfully in coronary artery bypass grafting on a 69-year-old woman. The left internal thoracic artery was harvested through a limited left anterior thoracotomy and anastomosed to the left anterior descending coronary artery on a protected and arrested heart. Intraoperative coronary angiography confirmed good graft patency. The patient was discharged from the hospital in good condition 7 days after the operation. This was the first successful minimally invasive Port-Access coronary artery bypass grafting in Japan.     

Minimally invasive coronary artery bypass grafting for the left anterior descending coronary artery.

OBJECTIVE: A single surgeon conducted One hundred and twelve patients underwent minimally invasive direct coronary artery bypass grafting for the left anterior descending coronary artery 112 patients at Yamato Seiwa Hospital from September 1996 until August 1999. METHODS: All procedures were performed via left anterior short thoracotomy using a stabilizer during graft anastomosis. RESULTS: No operative deaths occurred but 3 patients died while hospitalized due to noncardiac events. Graft occlusion was seen in 3 patients early postoperatively. Other angiography graft failure such as stenosis was seen in 11 patients. Occlusive lesions of other coronary arteries occurred in 77 patients (69%) and 53 patients underwent percutaneous transluminal coronary angioplasty the pre/postoperatively for those lesions. CONCLUSIONS: These results suggest that minimally invasive direct coronary artery bypass grafting is seen by cardiologists as a reasonable form of revascularization in conditioned patients having left anterior descending artery lesion, and that minimally invasive direct coronary artery bypass grafting has a spectrum of candidates different from that of conventional surgical revascularization for the coronary artery.     

Myocardial protective effect of lidocaine during experimental off-pump coronary artery bypass grafting.

Off-pump coronary artery bypass grafting (OPCABG) has recently gained popularity. During OPCABG, patients remain vulnerable to ischemic-reperfusion injury due to a temporary coronary occlusion without any active cardioprotection. Some strategies such as ischemic preconditioning (IP) and an intracoronary shunt have been applied with a view to minimizing the effects of ischemia, but the effects of these strategies remain controversial. This study was carried out to investigate the protective effect of lidocaine against myocardial ischemic-reperfusion injury. Twenty-one pigs were assigned to three groups, each consisting of seven pigs. In the control group, using a left internal thoracic artery (LITA) bypass circuit, the left anterior descending coronary artery (LAD) was occluded for 45 min followed by two hours of reperfusion. In the IP group, five min of occlusion followed by 15 min of reperfusion was performed. In the lidocaine group, 2 mg/kg of lidocaine was administered directly into the LAD just before the LAD occlusion. Infarct size expressed as a percentage of the area at risk was significantly smaller in the lidocaine group (2.7+/-4.2%) than in the control group (79.9+/-6.0%, p<0.001) or the IP group (57.0+/-25.9%, p<0.001). Lidocaine exhibited a potent myocardial protective effect in the present OPCABG model.