Outcome of Off-Pump CABG and the Future Perspectives. Results of Off-Pump CABG in 694 patients since 1993.

Hirofumi Takemura
Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan

Less invasive coronary artery bypass graft (CABG) is defined most commonly as having a small skin incision for the approach to the heart and for graft harvesting, avoidance of the use of cardiopulmonary bypass (CPB), or beating heart surgery with general anesthesia (OPCAB).

BeTEC (Beating heart total endoscopic CABG) was performed in 6 patients. Through 4 small keyholes, the mammary artery is harvested and the anastomosis of the left anterior descending artery is performed (Figure 1). A newly developed heart stabilizer facilitated this operation. After insertion into the thorax it curls itself up inside the thorax to transform into a circular heart stabilizer.

In one patient who underwent a MIDCAB, a skin incision of only 3 cm was needed because the ITA was harvested endoscopically. Another technique for LITA-LAD anastomsis is a lower partial sternotomy incision, with the anastomsis performed similarly to that in a full sternotomy operation.

The Mayo external vein stripper, a long metal bar with a small circle on the tip, is one technique for graft harvesting. It is inserted through a small groin incision and the large saphenous vein exposed and cut off. The vein stripper is slipped around the vein and a small incision made if resistance is felt. The vein is pulled out and branches detected and cut off. After taking the full length of the vein, the branches are clipped. Usually only 3 or 4 small skin incisions are sufficient to remove the saphenous vein from the groin down to the knee (Figure 2). This technique requires only about 15 minutes, about the same time required for standard skin incision technique. This group is working on removing the radial artery endoscopically.

Off-pump surgery

This group has performed OPCAB in 95% of all patients in their hospital since 1993. Considerations include graft selection, complete revascularization, safety, and results. Between 1993 and 2003, they performed OPCAB in 694 patients (553 male, 141 female, mean age 66 years, range 37-91 years). The diagnosis was old myocardial infarction in 525 patients, unstable angina in 88, and stable angina in 81 patients. Co-morbidities were CVA in 106 patients, difficult aorta in 88, chronic renal failure in 35, COPD in 16, re-do surgery in 32 patients, and malignancy in 32 patients. The approach used in these patients is shown in Figure 3.

The bypassed recipient arteries are shown in Figure 4. All coronary arteries were selected for target site and could be bypassed equally. The complete revascularization rate was 98.6% in the OPCAB patients and 90.4% in the MIDCAB patients. The mean number of grafts was 3.4 in OPCAB patients and 1.6 in MIDCAB patients.

To ensure safety, this group uses the coronary active perfusion system (CAPS), a mini extra-corporeal circulation that consists of a small pump to push the blood into the distal coronary artery during operation. CAPS ensures a safer OPCAB and removes the need to rush during anastomosis.

The graft patency rate is shown in Figure 5. The 30-day mortality was 1 death (0.14%) due to incomplete revascularization. In-hospital mortality was 1 death (0.14%), due to incomplete revascularization in a re-do case. Morbidity was stroke (cerebral bleeding) in 4 patients (0.5%), and exploration for bleeding in 4 patients (0.5%).

OFCAB in these 694 patients had a low rate of mortality and morbidity, a high rate of complete revascularization, and a high rate of graft patency.

Future perspectives

Least-invasive CABG, including endoscopic surgery, robotic surgery, hybrid OPCAB, and awake OPCAB, is the current focus of this group.

Awake off-pump CABG (AOCAB) has been performed in 6 patients with LAD single-vessel disease. Three patients received a GEA-LAD with a mid-abdominal incision; 1 patient had a LITA-LAD via MIDCAB; and 2 patients had a full sternotomy with a LITA-LAD, LITA-LAD, and branched RA-D1. No tracheal intubation was used, high thoracic epidural anesthesia was used, and all patients breathed spontaneously.

The degree of invasiveness of CABG as perceived by this group is illustrated in Figure 6. Standard CABG with midsternotomy, CPB, and intubation is becoming old-fashioned and its use is decreasing. At their hospital, OPCAB and MIDCAB are now the standard operation, and is used in 25% of CABG patients, including acute cases. For the future, approaches may be BeTEC, a hybrid procedure (PCI plus CABG), awake OPCAB, and robotic surgery.

Off-Pump CABG: Hybrid Procedure and Robotic Surgery

Akimitsu Yamaguchi
Hayama Heart Center, Kanagawa, Japan

Offpump coronary artery bypass surgery (OPCAB) has gained worldwide interest as minimally invasive cardiac surgery. The combination of percutaneous catheter intervention (PCI) and coronary artery bypass, a so-called hybrid procedure, can minimize the operative invasiveness. This group has begun endoscopic atraumatic coronary artery bypass (Endo A-CAB) using the AESOP endoscopic system. This procedure can further minimize sternum trauma or re-injury.

OPCAB was performed in 283 patients with a mean age of 68 years (28% female) between 1996 and 2001. Pre-operative coronary lesions were single vessel disease in 134 patients and multivessel disease in 149 patients. The indications for OPCAB were CVA in 52 patients, renal failure and heart disease in 36 patients, re-do CABG in 24 patients, difficult aorta in 26 patients, malignancy in 25 patients, peripheral vessel disease in 18 patients, hemorrhagic concerns in 11 patients, and cold in 18 patients. The remaining indications were social reasons.

The approach to the heart was full sternotomy in 161 patients, left thoracotomy in 91 patients (MIDACAB in 87 patients), subxiphoid in 7 patients, and lower half hemisternotomy in 24 patients. The graft materials and target vessels are shown in Figure 1.

Of the 149 cases with multivessel disease, complete revascularization was achieved with OPCAB in 82 patients (55%). Hybrid therapy was performed in 41 patients (27.5%), comprising a combination of OPCAB and PCI. This was performed on the same day as OPCAB or within 7 days. The site of PCI was the right coronary artery in 21 patients, left circumflex in 17 patients, diagonal in 2 patients, and left main trunk in 5 patients.

The patency achieved and the use of a heart stabilizer are shown in Figure 2. In-hospital death occurred in 5 patients (1.8%) and late death in 6 patients (2.1%).

Based on the good results with the hybrid procedure, they began using the Endo-A-CAB procedure, using endoscopic left internal thoracic artery harvest and LITA-LAD grafting through a small incision in the 4th intercostals space. The set-up of the operating room is shown in Figure 3. The AESOP endoscopic system is controlled by the surgeon’s voice command. Three ports are used for endoscopic LITA harvest. A port is placed between the 3rd and 4th intercostals space for the cautery, a port for the grasper through the 7th intercostal space, and a port for the endoscope through the 5th intercostal space. Anesthesia and single-lung ventilation using a double-lumen endotracheal tube to permit collapsing of the lung is performed. The patient is placed in a semioblique position supported by an inflatable pillow and is draped as for a conventional CABG procedure

The positioning of the patient is illustrated in Figure 4. When harvesting ITA using AESOP, the surgeon holds the electric cautery in the right hand and the grasper in the left hand. Voice commands spoken into a microphone control the endoscope. This group has performed endoscopic ITA harvest in 5 cases, as detailed in Figure 5.

Comparison of Endo-ACAB and MIDCAB

Harvest of LITA requires a 6-8 cm incision between the ribs, but the ACAB requires only tiny ports and a 4 cm incision. In MIDCAB there is substantial horizontal and vertical rib spreading, whereas there is none for ACAB. In MIDCAB, often cartilage or a rib is removed, which is not needed for ACAB. MIDCAB allows direct visualization, loop magnification is used, lighting is limited in the deep space, and a limited ITA length can be harvested. In contrast, ACAB uses high-resolution video, 10-15x magnification, excellent lighting from the scope, the full length can be harvested from the 1st to the 6th intercostals space, and the entire procedure can be recorded. With ACAB, the pericardium can be opened and the target vessel located endoscopically and the incision can be made directly over the target. ABCAB also provides for easier checking of graft bleeding.

This group concludes that the Endo-ACAB procedure and hybrid strategy can be used for multivessel disease. The rationale for the hybrid strategy is that LAD revascularization is the strongest predictor of prolonged life. The LITA graft has better long-term results than any other LAD therapy. Stenting results of other vessels (non-LAD) are comparable with surgery.

The patient is the real winner. No cardiopulmonary bypass is needed and complete revascularization is achieved, with minimal pain, a good cosmetic result, quick rehabilitation and return to work, and a good long-term result.