Off-pump arterial grafting: 125 cases using the Medtronic-Utrecht Octopus

MIECT: How did it start?

Transiently assuming the functions of both heart and lungs as surgeons repair critical valves and vessel lesions can be achieved by mechanical circulatory support has its origins in cardiopulmonary bypass (CPB). However, CPB technologies induce also some unintended adverse effects. During the 90s, a mayor trend pushed many physicians to reconsider the place of coronary artery bypass grafting (CABG) and challenged the surgical reference treatment by less invasive catheter-based angioplasties. Nevertheless, best long-term patient outcomes were related to surgery. Therefore, a small number of multidisciplinary teams in Regensburg and Paris started to develop a minimally invasive CPB system. The basic concept relied on a closed-loop perfusion circuit with a non-occlusive pump. Moreover, the team in Paris pushed the concept further and developed a complete fully integrated CPB system allowed first closed-heart and later open-heart surgery with aortic cross-clamping and efficient cardioprotection. Those were the initial steps towards the future developments of minimally invasive extracorporeal circulation technologies. Initial clinical results were clearly positive in terms of overall morbimortality. Moreover, several preliminary results pointed out the biological benefits that decreased hemodilution, improved preservation of the immune reactions and more stable anticoagulation could bring to the field of ECT.

A new instrument of suction support adapter system for epicardial radiofrequency ablation

OBJECTIVE

Recently, epicardial ablation on a beating heart has been conducted as a minimally invasive surgical procedure for atrial fibrillation. We have developed a suction support adapter with the aim of ensuring contact between the ablation probe and the atrial wall to obtain transmural coagulation, and we evaluated the effectiveness of the adapter in electrophysiologic and histopathologic procedures.

METHODS

To ensure contact between the radiofrequency ablation probe and the atrial wall, we designed and fabricated a suction support adapter. Twelve pigs were used in this study. A comparison was made between a group in which the ablation probe alone was used (group C, n = 6) and a group in which the ablation probe was used with the adapter (group S, n = 6). In both groups, epicardial ablation was conducted on a beating heart. An electrophysiologic evaluation was conducted to determine whether there was electrical isolation. Histopathologic evaluations were performed to identify the range of coagulation in the resected atrial wall specimens.

RESULTS

The coagulation range was significantly deeper in group S than in group C, and the breadth was significantly narrower. Transmural coagulation and electrical isolation of the atrial wall were seen in 1 case in group C and in all cases in group S.

CONCLUSIONS

Using the suction support adapter, we were able to maintain good contact between the ablation probe and the atrial wall. This device is thus thought to be useful for the safe and reliable performance of epicardial ablation on a beating heart.

Total Arterial Off-Pump versus On-Pump Coronary Revascularization:. Comparison of Early Outcome

BACKGROUND AND AIM

To assess differences in the early outcome after complete arterial myocardial revascularization with (ONCAB) or without cardiopulmonary bypass (OPCAB).

METHODS

Out of 870 consecutive CABG procedures 58 OPCAB and 91 ONCAB patients receiving exclusive arterial grafts were analyzed. OPCAB patients had more single-vessel (p < 0.0001), less triple-vessel (p < 0.0001) or left main disease (p = 0.0021), higher angina class (p = 0.003), unstable angina (p < 0.0001) or previous PTCAs (p < 0.0001).

RESULTS

ONCAB was associated with longer operations (182.5 +/- 38 vs. 147 +/- 56 min; p = 0.0001) and more anastomoses/patient (3.2 +/- 1 vs. 2 +/- 0.9; p < 0.0001), but incomplete revascularization was similar in both groups (11% vs. 17%; p = ns). ITA use was identical, whereas single left internal thoracic artery (LITA) use (25.9% vs.1%; p < 0.0001) and LITA jump anastomoses (10.3% vs. 7.7%; p < 0.0001) were more frequent in OPCAB. Radial artery (RA) use (89% vs. 46.6%; p < 0.0001) and RA jump anastomoses (57.1% vs. 12.1%; p < 0.0001) were more frequent in ONCAB. Mortality, arrhythmias, cerebro-vascular accidents (CVA), and renal failure were similar, but ventilatory support shorter (8.8 +/- 11.8 vs. 15.6 +/- 9.4 h; p < 0.0001) and cardiac enzyme release smaller (p < 0.0001) after OPCAB with a trend toward less myocardial infarction (1.7% vs. 7.7%; p = 0.12) and low output (1.7% vs. 8.8%; p = 0.089), and more respiratory complications (10.3% vs. 2.2%; p = 0.056).

CONCLUSIONS

Arterial OPCAB patients have less extensive CAD, but more severe symptoms. Early outcome is similar concerning mortality, arrhythmias, CVA, renal failure, or ICU and hospital stay, but with shorter ventilatory support and lower cardiac enzymes with a trend toward lower myocardial infarction and low output, but higher respiratory complication rates after OPCAB.

Effects of off-pump coronary surgery on the mechanics of the respiratory system, lung, and chest wall: Comparison with extracorporeal circulation

OBJECTIVE

To compare the effects of cardiac surgery with and without extracorporeal circulation on the mechanics of the respiratory system, lung, and chest wall. We also determined the time course of those effects.

DESIGN

Prospective, controlled study.

SETTING

An eight-bed, cardiac-surgical intensive care unit at a university hospital.

PATIENTS

Two groups of patients scheduled for elective coronary bypass surgery were studied: ten patients with extracorporeal circulation and 13 patients without extracorporeal circulation.

INTERVENTIONS

Measurement of esophageal pressure after insertion of an esophageal balloon catheter to separate respiratory system mechanics into lung and chest wall components. Measurements were performed preoperatively after induction of anesthesia (control), immediately postoperatively at arrival in the intensive care unit (time 1), and after 3 hrs (time 2). In 12 of the 23 patients, measurements were also performed 6 hrs postoperatively (time 3).

MEASUREMENTS AND MAIN RESULTS

No significant differences concerning demographics or surgical procedure were noticed between the two groups. Respiratory system, chest wall, and lung mechanics were obtained using the technique of rapid airway occlusion during constant-flow inflation. In both the group with and without extracorporeal circulation there was a significant increase in static and dynamic elastance of the respiratory system and lung at times 1 and 2, which tended to decrease again at time 3; chest wall elastance significantly increased at times 2 and 3 in the group without extracorporeal circulation, whereas the increase in chest wall elastance in the group with extracorporeal circulation occurred earlier (also at time 1). Additional resistance of the respiratory system and lung remained unchanged; chest wall resistance, however, significantly increased in both groups. Work of breathing significantly increased in both groups at times 1 and 2. There was a significant reduction in the Pao2/Fio2 ratio in both groups at times 2 and 3. No significant differences between the groups at any moment were noticed.

CONCLUSIONS

Coronary bypass surgery with and without extracorporeal circulation results in dramatic impairment of respiratory system mechanics. Based on respiratory system mechanics, early extubation after coronary artery bypass grafting should be performed with caution, no matter whether the off-pump or cardiopulmonary bypass technique is used.

Conversion to off-pump coronary bypass without increased morbidity or change in practice

BACKGROUND

This article examines the feasibility of complete conversion from conventional coronary artery operation to routine off-pump coronary bypass operation.

METHODS

Data on our first 285 off-pump procedures using the Octopus system (Medtronic Inc, Minneapolis, MN) represent our learning curve. This is a complete experience in coronary bypass surgery over 16 months.

RESULTS

The cohort was nonselected. All patients had at least two-vessel disease. Eight hundred seven grafts were performed (mean, 2.8 per patient) of which 647 grafts (84%) were arterial (mean, 2.3 per patient). One hundred seventy nine patients (63%) underwent total arterial revascularization. Eight patients required cardiopulmonary bypass; all other operations were completed off-pump. Complications were: mortality, 3 patients (1.5%); renal failure, 24 patients (8%); stroke, 2 patients (< 1%); and atrial fibrillation, 60 patients (21%). The morbidity data and frequency of arterial grafting did not differ from that of 355 patients who underwent coronary bypass operations in a preceding 18-month period.

CONCLUSIONS

Complete shift from routine use of cardiopulmonary bypass to nonselective off-pump coronary bypass operation is possible with a low conversion rate and without an apparent increase in morbidity or change in technique. Whereas short-term safety and efficacy seem certain, studies of long-term outcome are necessary before the eventual role of off-pump coronary bypass in myocardial revascularization can be defined.

Coronary artery bypass grafting with left internal mammary artery and right gastroepiploic artery, with and without bypass

BACKGROUND

Total arterial and off-pump revascularization are increasingly used in coronary artery bypass grafting. This study describes our experience with the exclusive use of both left internal thoracic artery and gastroepiploic artery by means of a median sternotomy, with and without cardiopulmonary bypass, in a subgroup of patients with two-vessel disease.

METHODS

From January 1995 to July 2000, 171 consecutive patients were reviewed in a prospective database. Ninety-one patients underwent coronary artery bypass grafting without cardiopulmonary bypass (group A), and 80 patients were operated on under cardiopulmonary bypass with aortic cross-clamp and cardioplegia (group B).

RESULTS

Patient data were similar in both groups except for the Euroscore (mean; 3.4+/-6.1, group A versus 2.5+/-4.5, group B; Euroscore > 6: 26.4%, group A versus 10%, group B; p < 0.05) and ejection fraction (mean, 54.6%+/-15.8%, group A versus 63.1%+/-12.7%, group B; p < 0.001). Severe aortic calcification was present in 6 group A patients, versus no patient in group B. Operative time was shorter in group A (185 versus 213 minutes, p < 0.0001), with less distal anastomoses (2.26 versus 2.5, p < 0.05). Conversion to cardiopulmonary bypass occurred in 1 patient, who was excluded from the study. Bleeding was higher in group A (852.6+/-288 mL versus 712.4+/-274 mL, p < 0.05), but transfusion was similar in both groups. Atrial fibrillation, postoperative inotropic support, and hospital stay were similar in both groups. Myocardial infarction was less frequent in group A (1 versus 4). Postoperative intraaortic balloon pump was used in 2 patients (group B). One patient died (group A) and 1 had an embolic stroke (group B). After discharge, 2 more patients died (group A, day 91; group B day 141), and 1 patient suffered an embolic stroke (group B). One patient in each group presented with dysfunction of the gastroepiploic artery graft requiring successful percutaneous transluminal angioplasty on the right posterolateral artery.

CONCLUSIONS

These results suggest that off-pump coronary artery bypass grafting using the left internal thoracic artery and gastroepiploic artery is safe even in high-risk patients. This approach allows an absolute no-touch technique of the aorta.