Direct myocardial revascularization without extracorporeal circulation. Experience in 700 patients

Value of reversed saphenous vein in minimally invasive direct coronary artery bypass graft procedures

BACKGROUND

Minimally invasive direct coronary artery bypass graft procedures are gaining acceptance for revision as well as primary coronary revascularization. When suitable, the left and right internal mammary arteries are preferred as bypass conduits; in other cases, the greater saphenous vein, used for standard coronary artery bypass graft procedures, may be useful to revascularize coronary artery branches during minimally invasive direct coronary artery bypass graft procedures.

METHODS

We used the greater saphenous vein on three occasions during minimally invasive direct coronary artery bypass graft procedures (1) to revascularize the left anterior descending coronary artery by anastomosis to the left axillary artery in the infraclavicular region, (2) as an extension to the left internal mammary artery to reach the left anterior descending coronary artery, and (3) as a bridge from the splenic artery to bypass the distal right coronary artery.

RESULTS

Postoperatively, all 3 patients had relief from symptoms of coronary artery insufficiency and none has been readmitted to the hospital with symptoms. Angiography or thallium studies were not performed to confirm graft patency because all patients were elderly and the risks of these procedures were considered to outweigh their potential benefit.

CONCLUSIONS

The greater saphenous vein is a potential bypass conduit for use in minimally invasive direct coronary artery bypass graft procedures as well as for coronary artery bypass graft procedures.

Intima-adventitia apposition in end-to-side arterial anastomosis: an experimental study in the pig

BACKGROUND

To prevent ischemic complications during coronary bypass grafting on the beating heart, a nonocclusive distal anastomosis technique is needed. One recently developed nonocclusive technique requires apposition of the intima of the graft to the adventitia of the recipient artery, in contrast to current surgical practice, which dictates apposition of both intimas.

METHODS

To compare the sole effect of intima-adventitia apposition (n = 18) versus traditional intima-intima apposition (n = 18), we investigated radiolabeled platelet deposition and histomorphologic aspects of vascular wall healing quantitatively in a porcine carotid artery bypass graft model. Both groups were evaluated at 2 hours, 2 days, or 4 weeks.

RESULTS

Within the first 2 hours, 3 of 6 pigs with intima-adventitia apposition exhibited cyclic flow reductions as a result of massive mural thrombosis. After intima-adventitia apposition, the number of deposited platelets was significantly higher compared with intima-intima apposition, 147.1 +/- 73.0 x 10(6) and 4.6 +/- 1.0 x 10(6) platelets/cm2 (mean +/- standard error of the mean), respectively (p = 0.03). At 2 days, the suture line was covered with small mural thrombi, whereas no thrombi were found after intima-intima apposition. At 4 weeks, intimal hyperplasia at heel and toe was not significantly different from that with intima-intima apposition.

CONCLUSIONS

Despite thrombotic phenomena in the early phase, intima-adventitia apposition yielded a patent anastomosis with a small intimal hyperplasia response.

Reduction of the inflammatory response in patients undergoing minimally invasive coronary artery bypass grafting

BACKGROUND

The aim of this prospective study was to determine whether the inflammation-associated clinical morbidity as well as the subclinical markers of the inflammatory response are reduced in patients who undergo minimally invasive coronary artery bypass grafting without cardiopulmonary bypass.

METHODS

From June 1995 to June 1996, 62 consecutive patients with isolated stenosis of the left anterior descending coronary artery were assigned randomly to two groups: 31 patients underwent minimally invasive coronary artery bypass grafting and 31 patients underwent conventional coronary artery bypass grafting with cardiopulmonary bypass. In a subgroup of 10 patients in each group, subclinical markers were measured to determine the level of the inflammatory response generated during the operation.

RESULTS

In the group that underwent minimally invasive coronary artery bypass grafting, leukocyte elastase, platelet beta-thromboglobulin, and complement C3a were unchanged at the end of the procedure compared with their baseline concentrations, whereas these inflammatory markers were increased significantly in the group that underwent conventional coronary artery bypass grafting with cardiopulmonary bypass. The patients who underwent minimally invasive coronary artery bypass grafting had a shorter duration of operation (104 +/- 28 versus 140 +/- 28 minutes; p < 0.01), less blood loss (312 +/- 167 versus 788 +/- 365 mL; p < 0.01), shorter ventilatory support (7.7 +/- 4.1 versus 12.9 +/- 3.4 hours; p < 0.01), and a shorter postoperative hospital stay (4.4 +/- 1.7 versus 7.7 +/- 2.6 days; p < 0.01) than the patients who underwent the conventional procedure.

CONCLUSIONS

These data suggest that patients who undergo minimally invasive coronary artery bypass grafting have a significant reduction in the systemic inflammatory response, postoperative morbidity, and hospital stay compared with patients who undergo conventional coronary artery bypass grafting with cardiopulmonary bypass.

[Reoperative coronary artery bypass grafting without cardiopulmonary bypass]

Between October 1995 and February 1997, 2 men and 4 women aged 53 to 75 years (mean, 66.3) underwent reoperative coronary artery bypass grafting without cardiopulmonary bypass. Isolated reoperative circumflex or intermediate artery bypass was performed through a left thoracotomy (n = 2), reoperative bypass to the left anterior descending coronary artery was performed through a median sternotomy (n = 3), and bypass to the right coronary artery was performed through an upper median laparotomy (n = 1). Single coronary bypass grafting utilizing arterial grafts (left internal thoracic artery: 3, right gastroepiploic artery: 3) was performed in all cases. There were no operative deaths. All cases required neither cathecolamine nor intraaortic balloon pumping). Peri/post operative blood transfusion was necessary in only one case. Postoperative coronary angiography revealed that the 6 arterial grafts were patent. Reoperative coronary artery bypass grafting without cardiopulmonary bypass can be performed with low perioperative morbidity and mortality, easy postoperative management, satisfactory graft patency, and good symptomatic improvement.

Perspectives on minimally invasive coronary artery surgery. Current assessment and future directions

Excellent long-term results have been obtained with conventional coronary artery bypass surgery. However, significant mortality and morbidity still exists due to the use of cardiopulmonary bypass for circulatory support and the traditional method of access by median sternotomy. Minimally invasive concepts have been adopted in cardiac surgery in an attempt to make these procedures less invasive. Minimally invasive alternatives include the minimally invasive direct coronary artery bypass procedure in which cardiopulmonary bypass is eliminated and the operation is performed through minimal access incisions; the Port Access approach in which the procedure is done through minimal access incisions and cardiopulmonary support is instituted through an extra thoracic approach. The third alternative is the "off pump" sternotomy approach which allows greater access for more extensive revascularization, but the procedure is still performed on a beating heart. All procedures have their limitations, but offer the potential for a less invasive approach for coronary revascularization. Current results are only short to immediate term, but are promising. Current efforts to extend the procedure include improved methods for facilitating beating heart coronary artery surgery, better visualization for endoscopic approaches and finding alternatives to cardiopulmonary bypass for circulatory support and alternatives to suturing for performance of vascular anastomoses. Additional alternatives to extend the procedure include hybrid operations in which minimally invasive coronary bypass is combined with transcatheter procedures (stents) for the treatment of multivessel disease.

Minimally invasive direct coronary artery bypass grafting: two-year clinical experience

BACKGROUND

Interest in minimally invasive coronary artery bypass grafting has been increasing.

METHODS

From April 1994 through December 1996, 199 patients (age, 36 to 93 years) underwent minimally invasive coronary artery bypass grafting through minithoracotomy, subxiphoid, and lateral thoracotomy incisions, with internal mammary artery, gastroepiploic artery, and composite grafts placed using local coronary artery occlusion.

RESULTS

The conversion rate to sternotomy was 7% (14/199). Preoperative risk factors included unstable angina (n = 83), reoperative coronary artery bypass grafting (n = 54), low ejection fraction (n = 53), congestive heart failure (n = 44), renal insufficiency (n = 25), chronic obstructive pulmonary disease (n = 36), cerebrovascular accident (n = 22), and diffuse vascular disease (n = 47). Morbidity included wound infections (n = 5), reoperation for management of bleeding (n = 6) and acute graft occlusion (n = 2), perioperative stroke (n = 1), atrial fibrillation (n = 14), and perioperative myocardial infarction (n = 7). The operative mortality was 3.8% (7/185). The number of grafts placed in 185 patients was as follows: single, 156; double, 28; and triple, 1. Early (less than 36 hours) angiography and Doppler flow assessment of the coronary anastomoses in 85% of the patients showed that 92% were patent. Routine use of mechanical stabilization of the coronary artery since April 1996 was found to be associated with an increase in the patency rate of the left internal mammary artery-left anterior descending coronary artery anastomosis to 97%, versus 89% (p = 0.055) associated with conventional immobilization techniques. Of the 148 patients followed up beyond 1 month (range, 1 to 32 months; mean, 9.2 +/- 7.4 months) postoperatively, 3 have died (3 to 7 months), and of the 145 survivors the cardiac-related event (percutaneous transluminal coronary angioplasty, reoperation, readmission for recurrent angina, and congestive heart failure)-free interval was 93%.

CONCLUSIONS

The minimally invasive coronary artery bypass grafting operation is safe and effective. Regional cardiac wall mechanical immobilization enhances the early graft patency and must be considered an essential part of this operation.

[Minimally invasive aortic valve replacement]

INTRODUCTION

Minimally invasive surgery is being applied to certain procedures in cardiac surgery. Aortic valve replacement presents the highest number of cases in which this approach is feasible.

MATERIAL AND METHODS

Fifteen patients, aged 16 to 75 years, underwent aortic valve replacement through a 10 cm incision at the level of the second intercostal space. Cardiopulmonary bypass was instituted through cannulation of the aorta and the femoral vein.

RESULTS

Adequate exposure of the aortic root was achieved in all cases. Valve replacement was accomplished with a mean ischemic time of 50 +/- 6 minutes and a pump time of 80 +/- 14 minutes. Mean chest drainage was of 310 +/- 251 ml. The patients were discharged between the third and the fifth day of the postoperative course.

CONCLUSIONS

A transverse incision at the level of the second intercostal space provides an excellent exposure for aortic valve replacement. Surgical times are not excessively prolonged and patient's recovery is faster and less painful than with the standard midline sternotomy.

On-pump, beating-heart coronary artery operations in high-risk patients: an acceptable trade-off?

BACKGROUND

Current cardioplegic techniques do not consistently avoid myocardial ischemic damage in high-risk patients undergoing coronary artery bypass grafting. Alternatively, revascularization without cardiopulmonary bypass is not always technically feasible. We investigated whether an intermediary approach based on maintenance of a beating heart with cardiopulmonary bypass support but without aortic cross-clamping might be an acceptable trade-off.

METHODS

Thirty-seven consecutive patients underwent coronary artery bypass grafting (with an average of two grafts per patient) in a pump-supported, non-cross-clamped beating heart. Inclusion criteria were poor left ventricular function (18 patients; mean ejection fraction, 0.25), evolving myocardial ischemia or infarction (11 patients, 5 of whom were in cardiogenic shock), and advanced age (3 patients; mean age 79.5 years) with comorbidities. Results were assessed primarily on the basis of clinical outcome. In addition, measurements of plasma levels of markers of myocardial damage (troponin Ic) and systemic inflammation (interleukin-6, interleukin-10, elastase) were done in 9 patients before and after bypass. In 6 patients, right atrial biopsy specimens were taken before and after bypass and processed by Northern blotting for the expression of messenger ribonucleic acid coding for the cardioprotective heat-shock protein 70. These biologic data were compared with those from control patients who underwent warm cardioplegic arrest within the same time span.

RESULTS

There was one cardiac-related death (2.7%), one Q-wave myocardial infarction, and no strokes. Four other deaths occurred from noncardiac causes, yielding an overall mortality rate of 13.5%. Limitation of myocardial injury was demonstrated by the minimal increase in postoperative troponin Ic levels (3.3 +/- 1.0 micrograms/L versus 6.6 +/- 1.5 micrograms/L in controls; p < 0.05) and the finding that heat-shock protein 70 messenger ribonucleic acid levels (expressed as a percentage of an internal standard) were significantly increased after bypass compared with pre-bypass values (279% +/- 80% versus 97% +/- 21%; p < 0.05). In the control group (cardioplegia), end-arrest values of heat-shock protein 70 messenger ribonucleic acid were not significantly changed from baseline (148% +/- 49% versus 91% +/- 29%), a finding suggesting a defective adaptive response to surgical stress. Conversely, peak levels of inflammatory mediators were not significantly different between the two groups. The eight grafts to the left anterior descending coronary artery that were assessed angiographically, by transthoracic Doppler echocardiography, or both methods were patent with satisfactory anastomoses.

CONCLUSIONS

In select high-risk patients, on-pump, beating-heart coronary artery bypass grafting may be an acceptable trade-off between conventional cardioplegia and off-pump operations. It is still associated with the potentially detrimental effects of cardiopulmonary bypass but eliminates intraoperative global myocardial ischemia.

Lesions of the target vessel during minimally invasive myocardial revascularization

BACKGROUND

Minimally invasive coronary artery bypass grafting has recently been introduced into cardiac surgery. In this report we discuss the incidence of surgically induced distal target vessel stenosis in patients who undergo the minimally invasive coronary artery bypass grafting procedure, which represents a major drawback of the procedure in our experience.

METHODS

Doppler evaluation of mammary artery flow was performed postoperatively in all 55 patients who underwent minimally invasive coronary artery bypass grafting at our institution. Angiography was performed in the first 35 consecutive patients for control purposes and in 2 patients who complained of angina recurrence.

RESULTS

In 32 of the first 35 consecutive patients, the anastomosis was found to be functioning normally and the distal left anterior descending artery was normal; in the remaining 3 patients we found mammary artery occlusion, anastomotic stenosis, and stenosis of the anastomosis and the distal left anterior descending artery in 1 patient each. A distal left anterior descending artery stenosis was found in the only 2 patients who underwent late angiography.

CONCLUSIONS

Surgically induced distal target vessel stenosis represents a major drawback of minimally invasive coronary artery bypass grafting in our experience. Further improvement in the means of achieving coronary artery occlusion, as well as in anticoagulant and antiplatelet therapy, is mandatory before minimally invasive coronary artery bypass grafting can be confidently accepted into clinical practice.

Lateral MIDCAB grafting via limited posterior thoracotomy

OBJECTIVE

Minimally invasive direct coronary artery bypass (MIDCAB) is a technique for coronary artery bypass grafting performed under direct vision without sternotomy or cardiopulmonary bypass. The approach has been used principally for primary single vessel grafting of the anterior or inferior coronary circulation. This initial experience presents a new lateral technique for patients with isolated circumflex coronary disease which can be used for both primary and reoperative revascularization with either saphenous vein or a free radial artery conduit.

METHODS

Lateral MIDCAB grafting of the circumflex coronary circulation was accomplished over a 33 month period at a single center using saphenous vein or free radial artery as the bypass conduit. Through a limited posterior thoracotomy, the lung is deflated and reflected superiorly. The pericardium is opened below the phrenic nerve to expose an obtuse marginal branch of the circumflex coronary artery. After heparinization, the coronary artery is temporarily occluded proximally and distally with local immobilization and an arteriotomy is performed. The distal anastomosis with running suture is followed by the proximal anastomosis on the descending aorta below the hilum of the lung using a side-biting clamp and radiopaque marker. Intraoperative transit time ultrasound flow measurements confirm adequate graft flow before wound closure.

RESULTS

To date, 19 patients have undergone this procedure with a mean follow-up of 12 months. A total of 12 patients received saphenous vein grafts and 7 patients received radial artery grafts. There was one death from arrhythmia on postoperative day 9. There was one elective conversion to conventional sternotomy due to inadequate exposure. Graft flows averaged 33.3 cc/min (range 5-87) and the mean postoperative length of stay was 4.5 days; 4 patients underwent recatheterization; 1 had graft occlusion and 2 received late postoperative catheter-based interventions. All patients are currently free of symptoms.

CONCLUSIONS

Lateral MIDCAB grafting provides focused revascularization to the circumflex distribution in both primary and reoperative settings. This approach avoids the hazards of resternotomy, eliminates cardiopulmonary bypass, and hastens postoperative recovery. These early results suggest the technique is effective at relieving symptoms and minimizing perioperative morbidity. Further experience at multiple centers will serve to define the ultimate capabilities of this new approach.

Minimally invasive versus conventional reoperative coronary artery bypass

BACKGROUND

Conventional reoperative (redo) coronary artery bypass grafting (CABG) is associated with significant morbidity. This retrospective study compared perioperative outcomes of conventional single-vessel redo CABG versus redo CABG done by a minimally invasive technique.

METHODS

Group A consisted of 23 consecutive patients from September 1995 to July 1996 who underwent single vessel redo CABG of the left anterior descending artery with the left internal mammary artery using a limited anterior thoracotomy without cardiopulmonary bypass; group B consisted of 12 consecutive patients from November 1984 to July 1994 who underwent the same procedure using a median sternotomy with cardiopulmonary bypass. The two groups were similar with regard to age, sex, preoperative ejection fraction, and risk stratification.

RESULTS

Mortality, cerebrovascular accidents, myocardial infarctions, and reoperations for bleeding were not significantly different between the groups. However, the patients in group A had significant reductions in atrial fibrillation, time to extubation, transfusions required, and length of cardiac recovery and hospital stay. With a mean of 12 +/- 6 months of follow-up, 87% of the patients in group A (20 of 23) are alive and asymptomatic. Actuarial survival rates for the patients in group B at 1, 2, and 10 years are 83%, 83%, and 72%, respectively.

CONCLUSIONS

Minimally invasive single-vessel redo CABG can be performed safely and may reduce the morbidity associated with conventional single-vessel redo CABG.

Minimally Invasive Coronary Artery Bypass Grafting

Minimally invasive coronary bypass surgery without the use of cardiopulmonary bypass has been introduced recently as a treatment for single or double coronary artery disease. Ten patients were operated on at this institute between September 1996 and January 1997. There was no operative mortality or perioperative myocardial infarction. The median hospital stay was 4 days (range 2 to 7 days). There was no reexploration for bleeding. The first 5 patients underwent postoperative coronary angiography prior to discharge. One showed a 70% stricture proximal to the anastomosis. Another patient had an occluded graft due to kinking and underwent reoperation. All patients were free of angina postoperatively. The minimally invasive technique facilitated early extubation, mobilization, and discharge from hospital. Long-term graft patency requires further evaluation by a randomized prospective trial.

Transmyocardial laser revascularisation combined with coronary artery bypass grafting without cardiopulmonary bypass

OBJECTIVE

To achieve complete myocardial revascularisation in patients with diffuse coronary artery disease, patients with inordinately high risk of cardiopulmonary bypass (CPB) like severe systemic disease or diffuse atherosclerosis of the aorta.

METHODS

We have adopted the technique of combining coronary artery bypass grafting (CABG) with transmyocardial laser revascularisation (TMLR) using 1000 W CO2 laser machine. TMLR is done to areas supplied by ungraftable arteries, while CABG without cardiopulmonary bypass is done to the left anterior descending artery (LAD) and/or right coronary artery (RCA). TMLR + CABG on beating heart without CPB has been performed on 56 patients. Age ranged from 37 to 81 years with a mean of 56.17. Four patients were in renal failure, two were redo CABG. Preoperatively 39.28% patients had angina class III and 10.71% had angina class IV. Four patients were on preoperative IABP support.

RESULTS

The mean number of grafts was 1.09. Internal thoracic artery (ITA) was used in 96.4% of the patients. Five patients showed elevation of CPK-MB, while three patients had an increase in Troponin T. Mortality was 1.8% (one patient died of intractable ventricular arrhythmia). The mean follow-up is 9.2 months. Myocardial perfusion scanning showed a stepwise improvement in reversible ischemia increasing from 52% at baseline to 91% at 12 months; 90.9% of the patients were angina free at 12 months. Metabolic stress test demonstrated an average increase in exercise tolerance from 5.2 min at baseline to 9.4 min at 12 months. Metabolic equivalents (METs) increased from 4.5 at baseline to 9.4 at 12 months. The average 44% Karnofsky score preoperative also increased to 86% at 12 months.

CONCLUSIONS

Our results indicate that the technique is surgically feasible and safe, with excellent short term results.

Coronary artery bypass grafting "on pump": role of three-day discharge

BACKGROUND

A new emphasis has been directed toward "off-pump" coronary artery bypass grafting to avoid the morbidity of cardiopulmonary bypass and further reduce the postoperative hospital length of stay. With the intent of achieving a hospital discharge for "on-pump" coronary artery bypass grafting procedures comparable with the same procedures "off pump," we applied a rapid-recovery protocol with particular attention paid to patients eligible for discharge on the third postoperative day.

METHODS

The cases of 104 consecutive patients who underwent isolated coronary artery bypass grafting using cardiopulmonary bypass were retrospectively reviewed. A rapid-recovery protocol emphasizing reduced cardiopulmonary bypass time, an anesthesia protocol for early extubation, perioperative administration of corticosteroids and thyroid hormone, and aggressive diuresis was applied to all patients. The goal during the first 24 hours postoperatively was to achieve early extubation as well as a mild state of negative fluid balance and to ensure absence of postoperative bleeding and a safe transfer from the intensive care unit to a monitored floor. On the second postoperative day, chest drains were discontinued, and aggressive ambulation therapy was instituted. If at 72 hours postoperatively the patient was walking without assistance, had return of normal bowel function, and had no atrial fibrillation, a 3-day discharge home was planned.

RESULTS

The 30-day mortality rate for the entire group was 1.9%. The average postoperative hospital length of stay for the entire series was 4.8 +/- 2.4 days. Of the 102 survivors, 30 patients (29%) were discharged within 3 days postoperatively (group 1), and 72 patients (71%) were discharged after the third postoperative day (group 2). Patients in group 1 were younger and had fewer comorbid conditions. Compared with group 2, group 1 had fewer patients with diabetes (7% versus 28%; p < 0.05), congestive heart failure (7% versus 18%), symptomatic vascular disease (0% versus 11%), chronic obstructive pulmonary disease (0% versus 10%), ambulatory difficulties (0% versus 10%), and the requirement of an intraaortic balloon pump preoperatively (13% versus 35%). Group 1 patients also had almost no complications and a lower readmission rate (3.3% versus 6.9%).

CONCLUSIONS

With the application of a rapid-recovery protocol to patients undergoing "on-pump" coronary artery bypass grafting, discharge home within 3 days postoperatively is attainable and safe for patients who have minimal comorbid conditions.

Monitoring considerations for port-access cardiac surgery

BACKGROUND

A method for monitoring patients was evaluated in a clinical trial of minimally invasive port-access cardiac surgery with closed chest endovascular cardiopulmonary bypass.

METHODS AND RESULTS

Cardiopulmonary bypass was conducted in 25 patients through femoral cannulas. An endovascular pulmonary artery vent was placed in the main pulmonary artery through a jugular vein. For mitral valve surgery, a catheter was placed in the coronary sinus for delivery of cardioplegia. A balloon catheter ("endoaortic clamp," EAC) used for occlusion of the ascending aorta, delivery of cardioplegia, aortic root venting, and pressure measurement was inserted through a femoral artery and initially positioned by use of fluoroscopy and transesophageal echocardiography (TEE). Potential migration of the EAC was monitored by (1) TEE of the ascending aorta, (2) pulsed-wave Doppler of the right carotid artery, (3) balloon pressure, (4) comparison of aortic root pressure and right radial artery pressure, and (5) fluoroscopy. TEE, fluoroscopy, and pressure measurement were effective in monitoring catheter insertion and position. With inadequate balloon inflation, migration of the EAC toward the aortic valve could be detected with TEE. During administration of cardioplegia, TEE showed movement of the balloon away from the aortic valve, and migration into the aortic arch was detectable with loss of carotid Doppler flow. Stability of EAC position was demonstrated with appropriate balloon volume. Cardioplegic solution was visualized in the aortic root, and aortic root pressure changed appropriately during administration of cardioplegia. Venous cannula position was optimized with TEE and endopulmonary vent flow measurement.

CONCLUSIONS

An effective method has been developed for monitoring patients and the catheter system during port-access cardiac surgery.

Predictors of early and overall outcome in coronary artery bypass without cardiopulmonary bypass

OBJECTIVE

Cardiopulmonary bypass in coronary artery bypass graft operations may adversely affect the outcome especially in high-risk patients. The purpose of this study is to evaluate results of coronary artery bypass performed without cardiopulmonary bypass, in a relatively high-risk cohort, and to identify predictors of unfavorable outcome.

METHOD

Three hundred and thirteen (313) patients, 246 (79%) of whom had high-risk conditions, who have a coronary anatomy suitable for coronary artery bypass surgery without cardiopulmonary bypass, underwent this procedure between December 1991 and July 1995. Mean number of grafts/patient was 1.8 (1-5), and only 71 patients (23%) received a graft to the circumflex coronary system.

RESULTS

Early unfavorable outcome events included operative mortality (12 patients, 3.8%), nonfatal perioperative myocardial infarction (eight patients, 2.6%), emergency reoperation (three patients, 0.9%), sternal infection (five patients, 1.6%), and nonfatal stroke (two patients, 0.6%). Multivariate analysis revealed angina pectoris class IV (odds ratio 5.4) and age > or = 70 years (odds ratio 5.0) as independent predictors of early mortality. Preoperative risk factors such as repeat coronary artery bypass grafting (50 patients, 16%), ejection fraction < or = 0.35 (85 patients, 27%), acute myocardial infarction (86 patients, 28%), cardiogenic shock (ten patients, 3.2%), chronic renal failure (25 patients, 8%), chronic obstructive pulmonary disease (20 patients, 6%), and peripheral vascular disease (51 patients, 16%) did not increase early mortality. During 33 months of follow-up (range 1-57 months), there were 42 deaths, at least 16 cardiac-related (one and four years actuarial survival of 90% and 76% respectively), and 39 patients (12.5%) in whom angina returned. Calcified aorta (odds ratio 2.6) and old myocardial infarction (odds ratio 1.8) were independent predictors of overall unfavorable events.

CONCLUSIONS

Coronary artery bypass grafting without cardiopulmonary bypass can be performed with relatively low operative mortality in certain high-risk subgroups of patients; however, an increased risk of graft occlusion is a potential disadvantage. This procedure should therefore be considered only for patients with suitable coronary anatomy, in whom cardiopulmonary bypass poses a high risk. Although the risk of stroke is relatively low, the procedure is still hazardous for patients aged 70 years and over.

A survey on minimally invasive coronary artery bypass grafting

BACKGROUND

There is increasing interest in performing minimally invasive coronary artery bypass grafting. To evaluate the current level of acceptance and utility of this procedure a survey of 162 cardiothoracic surgeons was conducted.

RESULTS

Currently only 16% of surveyed surgeons performed more than 10 minimally invasive coronary artery bypass grafting procedures. Most were less than 55 years old and in private practice. The majority predicted that it will be indicated in less than 25% of coronary artery bypass grafting cases and considered minimally invasive coronary artery bypass grafting a modification of existing techniques rather than investigational. Most believed exposure and stabilization of the coronary arteries on the beating heart to be the most challenging part and expressed concern with quality of the anastomosis.

CONCLUSIONS

We conclude that minimally invasive coronary artery bypass grafting is rapidly gaining acceptance in younger surgeons as techniques are improved. Despite concerns with adequacy of anastomosis the procedure is not considered investigational and follow-up is not rigorous.

Clinical assessment of functional stenosis severity: use of coronary pressure measurements for the decision to bypass a lesion

BACKGROUND

In the selection of patients eligible for minimally invasive coronary artery bypass grafting (MICABG), knowledge about the pathophysiologic significance of individual coronary stenoses is important. Only if the lesion amenable to MICABG can be identified as the culprit lesion, and other lesions can be demonstrated not to be responsible for reversible ischemia, will MICABG be an appropriate procedure.

METHODS

By simultaneous measurement of mean aortic pressure and transstenotic coronary pressure, a pathophysiologic index can be obtained that specifically indicates the influence of an epicardial coronary stenosis on maximum achievable blood flow of the supplied myocardial territory. This index is called myocardial fractional flow reserve (FFR(myo)).

RESULTS

Myocardial fractional flow reserve is a reliable, lesion-specific index for determining whether a particular stenosis is responsible for reversible myocardial ischemia. If FFR(myo) is less than 0.75, revascularization is indicated, whereas if FFR(myo) is greater than 0.75, revascularization usually is not warranted. Moreover, in contrast to classic coronary flow or flow velocity reserve, FFR(myo) is independent of changes in heart rate, blood pressure, and contractility, and also accounts for the contribution of collaterals.

CONCLUSIONS

Pressure-derived FFR(myo) is an accurate pathophysiologic index for reliable identification of functionally significant epicardial lesions and can be obtained easily and quickly during routine cardiac catheterization. Therefore, FFR(myo) facilitates clinical decision-making with respect to the appropriateness of MICABG.

Minimally invasive coronary artery bypass grafting: on the beating heart and via limited access

Minimally invasive coronary artery bypass grafting (MICABG) may be achieved by arterial grafting on the beating heart, without cardiopulmonary bypass, and by operations via limited access. The Second Utrecht MICABG Workshop held October 4-5, 1996, focused on beating-heart coronary immobilization, limited-access thoracoscopic and direct-vision mobilization of the internal mammary artery, limited-access left anterior descending coronary artery grafting, and, finally, facilitated distal anastomosis techniques. It has yielded 33 reports in this supplement. The combined, cumulative experience of a number of participants exceeded 3,000 beating-heart cases, including more than 1,000 with arterial grafting through limited access. The average number of anastomoses per patient ranged from 1.0 to 2.0. Therapeutic strategies are evolving, and dedicated instrumentation is being developed. Randomized clinical trials with angiographic follow-up are required to establish that the reduction in invasiveness of coronary bypass grafting is not achieved at the expense of suboptimal quality of the arterial graft and the distal anastomosis.

Anastomotic complications in minimally invasive coronary bypass grafting

BACKGROUND

Anterior wall myocardial revascularization through a left anterior minithoracotomy is an increasingly accepted procedure. Technical failure at the anastomotic site, promoting persistent or recurrent angina, is known to occur and may be underrecognized. This report summarizes the incidence of technical failure in an initial clinical experience and describes potential causes of early postoperative complications.

METHODS

Between December 1995 and May 1996, 15 patients underwent left internal mammary artery-to-left anterior descending artery revascularization without extracorporeal circulation. The surgical indication was single-vessel coronary disease in all patients. We exposed the left anterior descending artery target site through a 10-cm left anterior fourth space thoracotomy. The fourth costal cartilage was resected and the left internal mammary artery was harvested under direct visualization. Two 4-0 polypropylene sutures snared in tourniquets proximal and distal to the anastomotic site were used to obtain a bloodless field and stabilization of the left anterior descending artery.

RESULTS

All patients had procedures initially deemed successful based on disappearance of angina or postoperative transthoracic Doppler examination of the internal mammary artery 3 to 5 days postoperatively. However, 3 patients presented with recurrent angina at 2, 6, and 8 weeks. Angiography or direct visualization at operation demonstrated the technical complication (stenosis at the anastomotic site in 2 and snare injury in the native vessel in 1). Two patients required reoperation.

CONCLUSIONS

Initial results with minimally invasive coronary bypass grafting have generated great enthusiasm worldwide, but there is no consensus on how the procedure should be performed. These results suggest that a nonstabilized anastomosis results in an unacceptable failure rate. Furthermore, sutures encircling the left anterior descending artery should not be used for vessel stabilization as injury of the artery may occur.

Minimally invasive coronary artery bypass grafting decreases hospital stay and cost

OBJECTIVE

The authors performed a retrospective cost analysis for patients undergoing revascularization of their left anterior descending (LAD) coronary artery either by standard coronary artery bypass grafting (CABG), percutaneous transluminal coronary angioplasty (PTCA), or minimally invasive coronary artery bypass grafting (MICABG).

SUMMARY BACKGROUND DATA

Minimally invasive CABG has become a safe and effective alternative treatment for single-vessel coronary artery disease. However, the acceptance of this procedure as a routine alternative for the treatment of coronary artery disease will depend on both long-term graft patency rates as well as a competitive market cost.

METHODS

The authors conducted a retrospective analysis of three patient groups undergoing LAD coronary revascularization from January 1995 to July 1996. Ten patients were selected randomly from this period after PTCA of an LAD lesion with or without stenting. Nine patients underwent standard CABG on cardiopulmonary bypass with a left internal mammary artery. Nine patients received MICABG via a limited left anterior thoracotomy and left internal mammary artery to LAD grafting without the use of cardiopulmonary bypass.

RESULTS

Percutaneous transluminal coronary angioplasty (n = 10) was unsuccessful in two patients. One patient in the MICABG group (n = 9) was converted successfully to conventional CABG because of an intramyocardial LAD and dilated left ventricle. There was no operative morbidity or mortality in any group. Average length of stay postprocedure was decreased significantly for both the MICABG and PTCA groups when compared with that of conventional CABG (n = 9) (2.7 + 0.26, p = 0.009, and 2.6 + 0.54, p = 0.006, vs. 4.8 + 0.46, respectively). Total hospital costs for the MICABG and PTCA groups were significantly less when compared with those of standard CABG ($10,129 + 1104, p = 0.0028, and $9113 + 3,039, p = 0.0001, vs. $17,816 + 1043, respectively). There were no statistically significant differences between the MICABG and PTCA groups.

CONCLUSIONS

The final role of minimally invasive CABG is unclear. This procedure is clearly cost effective when compared with that of PTCA and conventional CABG. The long-term patency rates for MICABG will determine its overall efficacy.

Initial experience using an intraluminal shunt during revascularization of the beating heart

BACKGROUND

For decades, surgeons have relied on extracorporeal circulation and induced cardiac asystole to provide a bloodless, motionless field in which to construct coronary bypass grafts. However, the technique of coronary grafting without heart-lung support is now being revitalized. The current resurgence of off-pump coronary artery bypass grafting and the advent of less invasive incisions make it imperative that technical advances be applied to maximize the safety of these procedures.

METHODS

This report describes an inexpensive intraluminal shunt that maintains coronary perfusion, prevents ischemia, reduces backbleeding, and molds the suture line to prevent accidental missuturing of the posterior coronary wall.

RESULTS

In 63 patients, saphenous grafts were placed to the left anterior descending (49), diagonal (9), and right coronary artery (27) without extracorporeal circulation using an intraluminal shunt. There were no deaths (0% mortality) and one perioperative infarction (1.5%). Complication and graft patency rates were comparable with those obtained by conventional techniques.

CONCLUSIONS

Temporary intraluminal shunting greatly facilitates the surgeons' operative environment by permitting safe and precise construction of coronary artery grafts on the beating heart in a bloodless field. Intraluminal shunting may have future implications on the ability to perform safe and reproducible grafting on the beating heart through minimally invasive or endoscopic approaches.

Coronary bypass grafting via minithoracotomy on the beating heart

BACKGROUND

Recently the availability and the superiority of less invasive coronary artery bypass grafting on some selected groups of patients in the meaning of patient comfort and short hospital stay has been shown by some authors. We present here the clinical results of 40 patients operated on by minithoracotomy incision on the beating heart without using cardiopulmonary bypass mostly harvesting the left internal thoracic artery by videothoracoscopic assistance.

METHODS

Between March 1996 and September 1996, 40 patients were operated on by harvesting the left internal thoracic artery mostly by video-assisted thoracoscopy and performing bypass through a minitoracotomy incision. Two patients in whom the procedure was switched to conventional technique were not included in this series. Nine of the patients were female and the rest were male. The mean age was 43.2 +/- 7.

RESULTS

Left internal thoracic arteries were harvested by video-assisted thoracoscopy completely in 11 patients, incompletely in 24 patients (the harvesting was completed by direct vision afterwards), and under direct vision in 5 through a mini-anterior thoracotomy incision. Thirty-six patients received a bypass graft to left anterior descending coronary artery only, whereas 4 received a diagonal branch graft also. Left internal thoracic arteries were used to bypass the left anterior descending coronary artery directly in 38 patients. The left internal thoracic artery was injured in the middle portion during harvesting in 1 of the remaining 2 patients. The length was not enough in the other. A short saphenous vein graft was interposed between the left internal thoracic artery and the left anterior descending coronary artery in these 2 patients. There was no mortality. One patient had perioperative myocardial infarction. We did not see serious morbidity except one lung injury due to the trochar.

CONCLUSIONS

The results obtained from our experience suggest that coronary artery bypass grafting by minithoracotomy could be applied effectively and safely without overwhelming additional risk to the patient. Furthermore, it has some advantages in reducing operative trauma and cost and also improving patient comfort.

Port-access cardiac operations with cardioplegic arrest

BACKGROUND

A less invasive approach to cardiac surgery has been propelled by recent advances in video-assisted surgery. Previous obstacles to minimally invasive cardiac operations with cardioplegic arrest included limitations in operative exposure, inadequate perfusion technology, and inability to provide myocardial protection.

METHODS

Port-access technology allows endovascular aortic occlusion, cardioplegia delivery, and left ventricular decompression. The endoaortic clamp is a triple-lumen catheter with an inflatable balloon at its distal end. Antegrade cardioplegia is delivered through a central lumen, which also acts as an aortic root vent, a second lumen is used as an aortic root pressure monitor, and a third lumen is used for balloon inflation to provide aortic occlusion.

RESULTS

Experimental and clinical studies have demonstrated the feasibility of port-access coronary artery bypass grafting and port-access mitral valve procedures. Endovascular cardiopulmonary bypass using the endoaortic clamp was effective in achieving cardiac arrest and myocardial protection to allow internal mammary artery to coronary artery anastomosis in a still and bloodless field. Intracardiac procedures, such as mitral valve replacement or repair, have been successfully performed clinically.

CONCLUSION

The port-access system effectively achieves cardiopulmonary bypass and cardioplegic arrest, thereby enabling the surgeon to perform cardiac procedures in a minimally invasive fashion. This system provides for endovascular aortic occlusion, cardioplegia delivery, and left ventricular decompression.

Primary coronary artery bypass grafting without cardiopulmonary bypass in impaired left ventricular function

BACKGROUND

Conventional coronary artery bypass grafting using cardiopulmonary bypass carries relatively high mortality and morbidity for patients with left ventricular dysfunction.

METHODS

Seventy-five patients with ejection fraction less than or equal to 0.35 underwent primary coronary artery bypass grafting without cardiopulmonary bypass between December 1991 and December 1994. Thirty-two patients (43%) had congestive heart failure, 11 (15%) were referred for operation within the first 24 hours of evolving myocardial infarction, and 21 (28%) up to 1 week after acute myocardial infarction. Eighteen patients (24%), 6 of whom were in cardiogenic shock, underwent emergency operations.

RESULTS

Mean number of grafts/patient was 1.9 (range, 1 to 4), and internal mammary artery was used in 66 patients (85%). Only 17 patients (23%) received a graft to a circumflex marginal artery. Two patients (2.7%) died perioperatively, and 1 (1.3%) sustained stroke. At mean follow-up of 28 months, 13 patients had died, and angina had returned in 7 (10.5%). One- and four-year actuarial survival was 96% and 73%, respectively.

CONCLUSIONS

Coronary artery bypass grafting without cardiopulmonary bypass is a viable alternative to conventional coronary artery bypass grafting particularly for patients with extreme left ventricular dysfunction or those with coexisting risk factors, such as acute myocardial infarction and cardiogenic shock.

Video-assisted coronary bypass grafting on the beating heart

BACKGROUND

Concepts to make coronary artery bypass operations less invasive include minimization of access incisions, elimination of cardiopulmonary bypass, and no manipulation of the aorta. A spectrum of minimally invasive coronary bypass procedures now exist that eliminate the median sternotomy (port-access approach), cardiopulmonary bypass ("off-pump bypass"), or both (minimally invasive direct coronary artery bypass procedure). Although all have advantages in decreasing the morbidity of myocardial revascularization, significant limitations exist including surgeon experience, access, exposure, visualization, hemodynamic support, and technique of anastomosis.

METHODS

In an attempt to extend the applicability of the current minimally invasive techniques, efforts are being made both to extend the indications for the procedure as well as to modify the technical aspects. Our current experimental protocol involves a ports-only approach with three-dimensional video imaging, percutaneous Hemopump circulatory support, Octopus coronary immobilization, and an endoscopically sutured coronary anastomosis.

RESULTS

In a series of animal studies we have been able to successfully accomplish a totally endoscopic coronary artery bypass procedure on a beating heart without cardiopulmonary bypass.

CONCLUSIONS

Although endoscopic coronary artery bypass without cardiopulmonary bypass is possible, many technical challenges remain. Three-dimensional video imaging, wall motion immobilization and presentation, and an axial-flow device can facilitate the procedure. Future enabling technology including motion robotics and nonvisual imaging systems may ultimately further minimize the invasiveness of surgical myocardial revascularization.

Mammary-coronary artery anastomosis without cardiopulmonary bypass through a minithoracotomy

BACKGROUND

Coronary artery bypass grafting has been based on cardiopulmonary bypass, myocardial protection, and the median sternotomy. The recent concept of minimally invasive coronary artery bypass grafting in selected patients has dramatically affected surgical management of coronary artery disease. Coronary artery bypass grafting of anterior coronary arteries with in situ internal mammary artery through a limited anterior thoracotomy is a procedure that is gaining acceptance.

METHODS

Fifty-one patients were operated on by minithoracotomy and direct coronary artery bypass grafting without cardiopulmonary bypass. Left internal mammary artery-to-left anterior descending coronary artery anastomosis was done in 50 patients, and in 1 patient, left internal mammary artery-to-left anterior descending artery and right internal mammary artery-to-right coronary artery anastomoses were constructed through bilateral minithoracotomies. Left anterior minithoracotomy through the fourth intercostal space and right anterior minithoracotomy through the fifth intercostal space were used for left internal mammary artery and right internal mammary artery dissection, respectively. With this approach, a 4- to 6-cm length of mammary artery was easily dissected. Mammary-to-coronary anastomosis was performed on a beating heart without cardiopulmonary bypass through window pericardiotomy.

RESULTS

Twenty-five patients were extubated in the operating room and 26 in the intensive care unit 4 to 6 hours after operation. None of these patients required blood transfusion or inotropic support. Postoperative predischarge angiography in 42 patients revealed adequate mammary-to-coronary flow in 40 patients. Doppler flow studies were also in accordance with angiographic findings. Forty-five patients are in our regular follow-up (mean follow-up, 6.23 +/- 1.34 months); 44 of them are in functional class I.

CONCLUSION

In our experience minithoracotomy is a safe, simple, and minimally invasive procedure. Favorable cost/benefit ratio has been achieved owing to no early or late mortality and minimal early morbidity. Postoperative angiography and Doppler flow study revealed excellent predictive long-term results.

Hemodynamic changes during displacement of the beating heart by the Utrecht Octopus method

BACKGROUND

Coronary bypass grafting of posterior circumflex branches requires full displacement of the heart (apex pointing ventrally), which, in the beating heart, results in an arterial pressure drop. We analyzed its origin.

METHODS

To facilitate displacement, the Utrecht "Octopus" method was applied in 8 anesthetized beta-blocked pigs and the beating heart was fully retracted.

RESULTS

Displacement decreased stroke volume from 75 +/- 17 mL (mean +/- standard deviation) to 43 +/- 13 mL (p < 0.001), a 44% +/- 3% decrease that resulted in a decrease in cardiac output by 32% +/- 5% (mean +/- standard error of the mean; p < 0.001), a decrease in mean arterial pressure by 26% +/- 5% (p < 0.01), and an increase in heart rate by 26% +/- 6% (p < 0.01). Right ventricular end-diastolic pressure increased from 5 +/- 1 to 8 +/- 1 mm Hg (p < 0.01). Twenty degrees head-down tilt normalized cardiac output and mean arterial pressure. Right ventricular end-diastolic pressure increased to 10 +/- 2 mm Hg (p < 0.001) and left ventricular end-diastolic pressure to 11 +/- 3 mm Hg (p < 0.01).

CONCLUSIONS

Displacement of the beating heart in the pig induced a 44% drop in stroke volume, which is attributed to biventricular interference with pump function. The Trendelenburg maneuver reestablished the control circulatory status at the expense of augmented right and left ventricular preloads and an increased heart rate.

Experimental off-pump grafting of a circumflex branch via sternotomy using a suction device

BACKGROUND

We have shown previously in the pig that coronary artery bypass grafting on the beating heart may be facilitated by local cardiac wall immobilization by a suction device ("Octopus") applied to the anterolateral side of the heart. The purpose of this study was to investigate the feasibility of the method on the posterolateral side.

METHODS

In a consecutive series of 8 pigs, after median sternotomy, the posterior wall was taken hold of by the Octopus and subsequently brought up anteriorly and immobilized while hemodynamics were monitored. A posterolateral branch of the circumflex artery was grafted with the left internal mammary artery. After the coronary artery was ligated proximally, the heart was repositioned. At 6 weeks, bypass graft angiography and functional testing (postocclusion hyperemia testing) were performed. After sacrifice, histologic examination of the anastomosis was performed.

RESULTS

Dislocation of the heart to expose the distal anastomosis site caused a minor drop in mean arterial blood pressure from 71 +/- 14 (baseline) to 63 +/- 6 mm Hg (dislocated) (not significant) and recovery to 70 +/- 12 mm Hg, 15 minutes after repositioning. Cardiac output decreased from 4.0 +/- 1.0 to 3.2 +/- 0.7 L/min (p = 0.02) and recovered to 4.3 +/- 0.3 L/min. No inotropic drugs were necessary. Anastomosing required 21.5 +/- 6.5 minutes. Baseline graft flow was 8 +/- 3 mL/min and increased threefold to 24 +/- 10 mL/min (p < 0.05) at postocclusive hyperemia testing. At sacrifice after 6 weeks (n = 8), graft flow increased fourfold from 5 +/- 2 to 20 +/- 8 mL/min (p = 0.002) (n = 7). At histologic examination all eight anastomoses were patent without stenosis or mural thrombus.

CONCLUSIONS

Off-pump coronary artery bypass grafting of the posterolateral circumflex branches using the Octopus method on the beating pig heart is feasible, with full patency maintained for at least 6 weeks.

Less invasive arterial CABG on a beating heart

BACKGROUND

Competitive status of percutaneous transluminal coronary angioplasty and stenting has stimulated an interest in minimally invasive direct coronary artery bypass grafting.

METHODS

Between April 1994 and September 1996,156 patients with a mean age of 67 +/- 10 years have undergone minimally invasive direct coronary artery bypass grafting via minithoracotomy, subxiphoid incision, or both with internal mammary artery, right gastroepiploic artery, and radial artery grafting using local coronary occlusion on a beating heart with immobilization of the coronary artery target sites with traction sutures and mechanical regional cardiac wall immobilization platform.

RESULTS

Morbidity included wound infection (3), reoperation for bleeding (5), atrial fibrillation (12), central nervous system complication (1), and perioperative myocardial infarction (5). Cardiac-related operative mortality was 1.2% (2/156). Predominantly single grafting was done in 128 patients. Routine angiographic and Doppler echocardiographic flow assessment of anastomotic patency showed an overall patency rate of 92%. In 52 recent consecutive patients in whom the regional cardiac wall mechanical stabilization platform was used, the patency rate of the left internal mammary artery-to-left anterior descending coronary artery graft was improved to 96.2%. With a mean followup of 9.2 +/- 7.4 months, cardiac event-free interval (percutaneous transluminal coronary angioplasty, reoperative coronary artery bypass grafting, or death) in 111 patients was 91%.

CONCLUSIONS

Minimally invasive direct coronary artery bypass grafting is safe and effective with good early and midterm clinical results, especially with left internal mammary artery-to-left anterior descending coronary artery grafting via minithoracotomy. Regional cardiac wall immobilization of coronary artery target sites enhances the early graft patency in a predictable manner (96.2%), and this method should be an essential part of all minimally invasive direct coronary artery bypass graft operations with left internal mammary artery-to-left anterior descending artery grafts via minithoracotomy. Further study is required to establish the long-term efficacy of minimally invasive direct coronary artery bypass grafting and the treatment of coronary artery disease.

Off-bypass coronary bypass grafting via minithoracotomy using mechanical epicardial stabilization

BACKGROUND

Minimally or less invasive surgical coronary revascularization has gained increasing interest along with new techniques and devices designed for easier and safer procedures. Until recently, it appeared questionable whether grafting techniques with avoidance of cardiopulmonary bypass techniques would allow adequate results compared with conventional techniques using cardioplegic arrest.

METHODS

Since June 1996, minimally invasive direct coronary artery bypass grafting procedures without cardiopulmonary bypass were intended in 24 patients (19 male, 5 female; age, 60.5 +/- 10.5 years) applying a special system (CardioThoracic Systems, Inc) for internal mammary artery access and epicardial surface stabilization approaching through an anterolateral minithoracotomy. Neither video-assisted preparation nor additional pharmacologic stabilization was applied. Concomitant risk factors and associated comorbidity were frequent.

RESULTS

The procedure was completed in 23 patients, grafting the left anterior descending coronary artery (n = 21) or diagonal branches (n = 3, 1 sequential) as scheduled. In 1 case with internal mammary artery dissection, cardiopulmonary bypass and sternotomy became necessary. Simultaneous carotid endarterectomy was performed in 1 patient. There were two episodes of intraoperative ventricular fibrillation; no other major complications occurred. Postoperative evaluation was obtained in 16 patients (15 by angiography, 1 by Doppler echocardiography) so far and revealed adequate graft function and patency.

CONCLUSIONS

Using specially designed instruments for internal mammary artery access and epicardial surface stabilization, minimally invasive direct coronary artery bypass grafting procedures via a minithoracotomy avoiding cardiopulmonary bypass techniques may be applied safely and successfully, even in increased risk constellations.

Safe and effective method of stabilization for coronary artery bypass grafting on the beating heart

BACKGROUND

There is an emerging interest in performing coronary artery bypass grafting on the beating heart. This study examines the efficacy and safety of two types of coronary artery stabilizers developed to perform coronary artery bypass grafting on the beating heart.

METHODS

Four dogs underwent left internal mammary artery to left anterior descending artery anastomosis using a retractor-fixed stabilizer. Measurements of hemodynamic indices and range of motion of the targeted arteriotomy were done before and after application of the stabilizers. Patency of the anastomosis was evaluated by angiography. To clinically validate the safety of this stabilizer, we collected data on 150 patients from centers that had access to the retractor-fixed stabilizer.

RESULTS

All animals survived the procedure with no ischemic changes or hemodynamic alterations. A significant reduction in range of motion (mm) of the left anterior descending coronary artery was achieved after application of the stabilizers. Angiographic studies showed good anastomotic patency. Histologic examination showed no myocardial injury. Patient data revealed successful completion of the anastomosis, with conversion to sternotomy or cardiopulmonary bypass in 1 patient each. Intraoperative and postoperative myocardial infarctions occurred in 1 patient each, with one in-hospital death.

CONCLUSIONS

Significant stabilization of targeted coronary arteries allowing the performance of safe and reliable anastomosis on a beating heart can be achieved using the stabilizer.

Indications and problems of coronary artery bypass grafting without cardiopulmonary bypass

As an alternative method of myocardial protection and to obviate the inherent risks of cardiopulmonary bypass (CPB), we have been performing coronary artery bypass grafting (CABG) without CPB in carefully selected patients. Since the first such operation was successfully performed in January 1995 on a patient with angina pectoris and lung cancer, four other patients have subsequently undergone this technique. This series of 5 patients, being 1 man and 4 women ranging in age from 68 to 80 years, is presented in this report. The reasons for the selection of this procedure were concomitant diseases including lung cancer, a calcified aorta, and myocardial infarction. The mean time of ischemia for each anastomosis was 15.3 +/- 5.3 min, and the maximum cardiac muscle creatine phosphokinase (CPK-MB) was less than 14 unit/l postoperatively. None of the patients required ventilatory support for longer than 24 h postoperatively, and oral intake was started within 24 h after extubation in all patients. Postoperative angiography confirmed graft patency and none of the patients developed any ischemic symptoms. All the patients were discharged between 1 and 2 months postoperatively. Thus, the off-pump technique is useful when concomitant diseases are present and will become an alternative method of treatment for coronary artery disease in selected patients.

Video-assisted minimally invasive coronary operations without cardiopulmonary bypass: a multicenter study

OBJECTIVE

The need to avoid the risks associated with cardiopulmonary bypass has led to the interest in coronary operations without cardiopulmonary bypass.

PATIENTS AND METHODS

From April 1994 to September 1995, 44 patients (mean age 63.3 +/- 10.0 years, range 43 to 83 years) were selected for video-assisted coronary artery bypass grafting without cardiopulmonary bypass through a small anterior thoracotomy. Mean preoperative ejection fraction was 50.7% +/- 13.4% (range 20% to 65%). Four patients had left ventricular dysfunction (ejection fraction below 35%). Thirty patients had stable angina (26 with class 3 angina) and 14 had unstable angina. One had recurrent angina (redo). In all cases a small (3.5 to 11 cm) anterior thoracotomy (43 left and one right) was performed and the harvesting of the left internal thoracic artery was video-assisted by thoracoscopy.

RESULTS

The left internal thoracic artery was used in 43 cases to graft the left anterior descending coronary artery; the right thoracic mammary was used in one case to graft the right coronary artery; the radial artery was used in one case to perform a T-graft to the first diagonal and first marginal branches. We recorded one death (2.3%) and one case of postoperative low cardiac output syndrome (2.3%). Perioperative myocardial infarction occurred in two cases (4.5%). We did not record noncardiac complications (cerebrovascular complications, kidney failure, prolonged ventilatory support, or wound complications). Supraventricular and ventricular arrhythmias were never detected.

CONCLUSION

According to our experience, video-assisted coronary bypass through a small anterior thoracotomy is a new promising technique that can be considered an alternative in most cases to angioplasty and complementary to conventional coronary operations.

Minimally invasive coronary artery bypass grafting

Minimally invasive coronary artery bypass grafting has recently been introduced into cardiac surgery. The procedure promises to become an important addition to the surgical treatment of coronary artery disease. This current review gives a historical perspective and an overview of this growing field, based on the experience of three international centers with experience with minimally invasive coronary artery bypass grafting. It is predicted that the field will grow, and that future generation of cardiac surgeons will have to become familiar with this new procedure.

"Keyhole" coronary artery bypass surgery

OBJECTIVE

The objective of this study was to identify the utility of "keyhole" thoracotomy approaches to single vessel coronary artery bypass surgery.

SUMMARY BACKGROUND DATA

Although minimally invasive surgery is efficacious in a wide variety of surgical disciplines, it has been slow to emerge in cardiac surgery. Among 49 selected patients, the authors have used a left anterior keyhole thoracotomy (6 cm in length) combined with complete dissection of the eternal mammary artery (IMA) pedicle under thoracoscopic guidance or directly through the keyhole incision to accomplish IMA coronary artery bypass grafting (CABG) to the left anterior descending (LAD) coronary artery circulation or to the right coronary artery (RCA).

METHODS

Keyhole CABG was accomplished in 46 of 49 patients in which this approach was attempted. All patients had significant (> 70%) obstruction of a dominant coronary artery that had failed or that was inappropriate for endovascular catheter treatment (percutaneous transluminal coronary angioplasty or stenting). Forty-four of the 49 patients had proximal LAD and 5 had proximal RCA stenoses. The mean age of the patients (35 men and 14 women) was 61 years, and their median New York Heart Association anginal class was III. The mean left ventricular ejection fraction was 42%. Femoral cardiopulmonary bypass support was used in 9 (19%) of 46 patients successfully managed with the keyhole procedure. Short-acting beta-blockade was used in the majority of patients (38 of 46) to reduce heart rate and the vigor of cardiac contraction.

RESULTS

As 49 patients have survived operation, which averaged 248 minutes in duration. Median, postoperative endotracheal intubation time for keyhole patients was 6 hours with 25 of 46 patients being extubated before leaving the operating room. The median hospital stay was 4.3 days. Conversion to sternotomy was required in three patients to accomplish bypass because of inadequate internal mammary conduits or acute cardiovascular decompensation during an attempted off-bypass keyhole procedure Postoperative complications were limited to respiratory difficulty in three patients and the development of a deep wound infection in one patient. Nine (19%) of 46 patients received postoperative transfusion. There have been no intraoperative or postoperative infarctions, and angina has been controlled in all but one patient who subsequently had an IMA-RCA anastomotic stenosis managed successfully with percutaneous transluminal coronary angioplasty.

CONCLUSIONS

These early results with keyhole CABG are encouraging. As experience broadens, keyhole CABG may become a reasonable alternative to repeated endovascular interventions or sternotomy approaches to recalcitrant single-vessel coronary arterial disease involving the proximal LAD or RCA.

Left anterior descending coronary artery grafting via left anterior small thoracotomy without cardiopulmonary bypass

BACKGROUND

We explored the possibility of anastomosing the left anterior internal mammary artery (LIMA) to the left anterior descending artery in a beating heart via a left anterior small thoracotomy.

METHODS

This procedure was performed in 155 of 162 scheduled patients; in 7 (4.3%) the left anterior descending artery was not suitable or was too small. The chest was opened in the fourth intercostal space (mean wound length, 10.5 cm) and the LIMA was harvested for about 4 cm. The left anterior descending artery was occluded by means of two 4/0 Prolene (Ethicon, Somerville, NJ) sutures, and the proximal suture was snared. The anastomosis was performed with two 8/0 Prolene sutures while the heart was beating. Early postoperatively all patients underwent repeat angiography or a Doppler flow assessment of the LIMA or both.

RESULTS

The LIMA was connected directly to the left anterior descending artery in 144 patients and with interposition of an inferior epigastric artery in 11. In 2 patients the diagonal branch was also grafted using an inferior epigastric artery from the LIMA. One patient (0.6%) died 38 days after the operation due to multiorgan failure. Nine patients (5.8%) had failure requiring a redo operation: 7 (4.5%) early and 2 (1.3%) late. One additional patient had a late percutaneous transluminal coronary angioplasty for anastomotic stenosis. At a mean 5.6 months of follow-up, 143 patients (92.2%) were alive, asymptomatic with or without medical treatment, and without cardiac events.

CONCLUSIONS

Left internal mammary artery-to-left anterior descending artery anastomosis performed on a beating heart via a left anterior small thoracotomy is a safe procedure. In selected patients the operation has good early and midterm results.

Coronary artery bypass grafting without cardiopulmonary bypass and without interruption of native coronary flow using a novel anastomosis site restraining device ("Octopus")

OBJECTIVE

This study assessed the feasibility of coronary artery bypass grafting on the beating heart without interruption of native coronary blood flow using a novel anastomosis site restraining device.

BACKGROUND

Recently, an end-to-side bypass technique was described that does not require interruption of flow in the recipient artery.

METHODS

By means of a suction device ("Octopus"), in 31 pigs the epicardium was grasped and immobilized through an arm contraption fixed to the operating table. In the first 15 consecutive pigs (study I), the two-dimensional motion of an epicardial beacon was monitored. In 16 subsequent pigs (study II), an internal mammary artery was grafted under the microscope in two steps to a proximal coronary artery segment, without cardiopulmonary bypass. First, the internal mammary artery was sutured end-to-side to the outside of the coronary artery. Secondly, an orifice was punched in the partitioning coronary wall by an excimer laser catheter introduced through a temporary side-branch of the internal mammary artery.

RESULTS

Study II: During 43 suction periods in four anastomosis areas, immobilization was achieved for 15 to 169 min (>30 h in total) in 13 open- and 9 closed-chest procedures without hemodynamic deterioration. The area circumscribed by the edges of the beacon trajectory (area in which the anastomosis is to be tracked) was reduced from 73.0 +/- 43.0 mm(2) (mean +/- SD) to 1.3 +/- 0.5 mm(2) (p<0.001) in the open-chest and to 0.2 +/- 0.2 mm(2) in the closed-chest procedure. At 6 weeks, no myocardial or coronary suction lesions were found. Study II: Nonocclusive anastomosis surgery required 25 +/- 3 min. No leakage, serious arrhythmias, graft closure or hemodynamic deterioration occurred during the procedure or for 2 h after ligating the coronary artery proximally. At 6 weeks, all seven grafts were patent.

CONCLUSIONS

Coronary bypass on the beating heart without interruption of coronary flow is feasible. In both open- and in closed-chest procedures, the "Octopus" reduced anastomosis site motion to about 1 X 1 mm without adverse consequences.

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 > or = 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.