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Ann Thorac Surg 1999;67:1018-1021
© 1999 The Society of Thoracic Surgeons

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Original Articles

Surgical results of video-assisted minimally invasive direct coronary artery bypass

^a Department of Cardiac Surgery, Christ Hospital and the Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA

Accepted for publication September 19, 1998.

Address reprint requests to Dr Wolf, Cardiovascular and Thoracic Surgeons, Inc, 2123 Auburn Ave, Suite 401, Cincinnati, OH 45219

	Abstract

Top Abstract Introduction Material and methods Results Comment Conclusions References

 
Background. A video-assisted minimally invasive direct coronary artery bypass procedure is defined as a combination of video thoracoscopic internal mammary artery harvest and direct coronary bypass grafting through a minithoracotomy without cardiopulmonary bypass. We reviewed our experience with this procedure and examined its efficacy.

Methods. Since November 1995, 110 patients have undergone a minimally invasive direct coronary artery bypass procedure in our institution. Seventy (64%) of them underwent a video-assisted minimally invasive operation (group 1). As a control group (group 2), we reviewed the results in 37 patients who underwent conventional single or double coronary artery bypass grafting using an internal mammary artery graft between 1993 and 1995 and could have been candidates for minimally invasive direct coronary artery bypass grafting.

Results. There were two hospital deaths (2.9%) in group 1 and one hospital death (2.7%) in group 2. There were no significant differences in mortality or morbidity between the two groups. The number of patients who needed postoperative positive inotropic agents was significantly greater in group 2, and this group also had a significantly longer mean postoperative intubation time and mean hospital stay than group 1.

Conclusions. The surgical results of video-assisted direct coronary artery bypass procedures were better than those of conventional coronary artery bypass grafting in this review. A long-term follow-up for graft patency is needed.

	Introduction

Top Abstract Introduction Material and methods Results Comment Conclusions References

 
The minimally invasive direct coronary artery bypass (MIDCAB) procedure, performed with smaller incisions and without cardiopulmonary bypass, is becoming more widely used [1–9]. In almost all such procedures reported, arterial grafts such as the left internal mammary artery (LIMA), the right internal mammary artery (RIMA), or the gastroepiploic artery have been used. Recently, repeat coronary artery bypass grafting (CABG) without the use of cardiopulmonary bypass has been reported with favorable results [10, 11]. The MIDCAB procedure, which is less invasive than conventional CABG, has been used for patients at high risk because of advanced age or poor left ventricular function [12].

Since November 1995, we have performed 110 MIDCAB procedures in our institution. A video-assisted minimally invasive direct coronary artery bypass (VADCAB) procedure was introduced for patients who needed a MIDCAB operation using the LIMA or RIMA. The VADCAB procedure is defined as a combination of video thoracoscopic internal mammary artery (IMA) harvest and direct CABG through a minithoracotomy (an incision 5 to 8 cm in length, with or without rib resection). We reviewed the charts of patients who underwent VADCAB procedures and clarified its efficacy compared with conventional CABG procedures.

	Material and methods

Top Abstract Introduction Material and methods Results Comment Conclusions References

 
Since November 1995, 110 patients have had a MIDCAB procedure in our institution. A VADCAB operation was attempted in 73 patients and performed in 70 (95.9%) (group 1). Age ranged from 38 to 89 years (mean age, 64.0 ± 12.1 years), and 6 patients (8.6%) were more than 80 years old. There were 43 men and 27 women. The distribution of the coronary lesions was as follows: left anterior descending coronary artery (LAD), 61 patients; right main coronary artery (RCA), 8; and posterior descending artery, 1 patient. Seven patients (10%) were having a redo procedure. The following grafts were placed: LIMA to LAD, 54 patients; RIMA to RCA, 8; LIMA to LAD and diagonal branch sequentially, 7; and RIMA to posterior descending artery, 1 patient.

As a control group (group 2), we reviewed the cases of 37 patients whose coronary lesions included the LAD or the RCA and who underwent conventional CABG using the IMA as a pedicle graft between 1993 and 1995 in our institution. All 37 patients could have been VADCAB candidates. Age ranged from 32 to 81 years (mean age, 59.8 ± 11.4 years), and only 1 patient (2.7%) was older than 80 years. There were 20 men and 17 women. The distribution of the coronary lesions was as follows: LAD, 35 patients, and RCA, 2. The following anastomoses were done: LIMA to LAD, 22 patients; LIMA to LAD and diagonal branch sequentially, 13; and RIMA to RCA, 2. One patient (2.7%) was having a redo procedure.

Operative technique of VADCAB
The surgical technique of thoracoscopic IMA harvest has previously been described in detail [13]. After the establishment of endotracheal general anesthesia with a double-lumen tube, the patient is placed in a 20- to 30-degree right or left lateral decubitus position, with abduction of the left or right arm for sufficient exposure of the axilla. Three small incisions are made. The highest two (about 5 mm in length) are in the third and fourth intercostal spaces in the midaxillary line and are for the Harmonic Scalpel (Ethicon Endo-Surgery, Cincinnati, OH) and an endoscopic Kitner dissector (Ethicon Endo-Surgery). The lowest one (about 10 mm in length) is in the fifth or sixth intercostal space in the anterior axillary line and is for the rigid 30-degree thoracoscope inserted through a 10-mm port. With low-flow carbon dioxide insufflation and the Harmonic Scalpel, the left or right IMA is dissected from its bed from the superior border of the first rib to the fifth or sixth rib. All branches of the IMA are controlled with the Harmonic Scalpel. An anterior thoracotomy (5 to 8 cm in length) is made in the fourth intercostal space. In most cases, the ribs are spread without resection, and the remainder of the IMA harvest is completed.

The pericardium is opened and the stabilizer, placed. After the administration of 10,000 units of heparin sodium, the LAD is encircled with two 3-0 Gore-Tex sutures proximally and distally. One suture is tightened for 5 minutes while the electrocardiogram and the arterial blood pressure are monitored to test for ischemia, and then released. If there are no manifestations of ischemia, both sutures are tightened, and an arteriotomy is made. The IMA graft is anastomosed end-to-side to the LAD using a running suture of 7-0 Prolene (Ethicon, Somerville, NJ). A chest tube is placed through the port site, and other incisions are closed.

Study protocol
We first compared the following risk factors in the two groups: age, redo procedure, low left ventricular ejection fraction, diabetes mellitus, and chronic obstructive pulmonary disease. Then we compared the following results in the two groups: mortality, morbidity, postoperative cardiac support, intensive care unit stay, postoperative intubation time, and hospital stay. The short-term graft patency in group 1 was reviewed.

Statistical analysis
The Student t test was used to compare patient age, intensive care unit stay, postoperative intubation time, and hospital stay. The Fisher exact probability test was used for the comparison of redo procedures, low left ventricular function, diabetes mellitus and chronic obstructive pulmonary disease, mortality, morbidity, and postoperative cardiac support between the two groups. A p value of less than 0.05 was considered significant.

	Results

Top Abstract Introduction Material and methods Results Comment Conclusions References

 
Risk factors
The mean age in group 1 was significantly greater than that in group 2 (64.0 ± 12.1 years versus 59.8 ± 11.4 years; p < 0.05). There were seven redo procedures (10%) in group 1, and one (2.7%) in group 2. There was a trend toward a greater frequency of repeat procedures in group 1, but there was no significant difference between the two groups (p = 0.17). Nine patients (12.9%) in group 1 had a left ventricular ejection fraction of less than 0.30 compared with 2 patients (5.4%) in group 2. Again, this difference between groups was not significant (p = 0.19), though there was a trend toward a greater number of patients with a low ejection fraction in group 1. Fifteen patients (21.4%) in group 1 and 6 (16.2%) in group 2 had diabetes mellitus (p = 0.35). In group 1, 11 patients (15.7%) had chronic obstructive pulmonary disease versus 2 patients (5.4%) in group 2. There was a trend toward a greater number of patients with this condition in group 1, but the difference between groups was not significant (p = 0.10).

Surgical results
There were two hospital deaths (2.9%) in group 1; one was due to an intestinal infarction and one, cardiac arrhythmias. There was one hospital death (2.7%) in group 2; it was due to low-output syndrome. The difference between the two groups was not significant (p = 0.73). Seven patients (10%) in group 1 experienced major postoperative complications: reoperation for bleeding, 2 patients; arrhythmia, 2; wound infection, 1; low-output syndrome, 1; and intestinal infarction, 1. In group 2, there were four patients (10.8%) with major complications: pneumonia, reoperation for bleeding, low-output syndrome, and cerebral infarction, 1 patient each. There was no significant difference in morbidity between the two groups (p = 0.69).

Nine patients (12.9%) in group 1 needed positive inotropic agents postoperatively versus 17 (45.9%) in group 2 (p < 0.001) (Table 1). Postoperatively, the mean intensive care unit stay in group 1 was 29.0 ± 20.5 hours compared with 39.1 ± 39.7 hours in group 2. There was a trend toward a longer mean stay in group 2 than in group 1, though the difference was not significant (p = 0.08). In group 1, 55 patients (78.6%) were extubated in the operating room. The mean postoperative intubation time in group 1 was 2.2 ± 5.0 hours versus 18.2 ± 25.5 hours in group 2 (p < 0.01). The mean duration of hospital stay in group 1 was 4.2 ± 2.1 days (range, 2 to 10 days) compared with 5.9 ± 2.3 days (range, 4 to 15 days) in group 2 (p < 0.0001).

The mean follow-up was 13.9 months. Six-month follow-up Doppler assessment of 32 grafts in 31 patients showed 31 grafts patent. For four grafts in 4 patients, 6-month follow-up coronary angiography was performed and showed all grafts patent. The total short-term graft patency of the VADCAB procedure is 97.2%.

	Comment

Top Abstract Introduction Material and methods Results Comment Conclusions References

 
The MIDCAB procedure is gaining acceptance [1–9]. In almost all such procedures reported, arterial grafts (LIMA, RIMA, or gastroepiploic artery) have been used because a proximal anastomosis is not necessary, and a 10-year patency rate of 90% is expected. Because it is less invasive than conventional CABG, the MIDCAB operation has been recommended for patients at high risk because of advanced age or poor left ventricular function, particularly those requiring a reoperation, who have a suitable anatomy [12]. Favorable results of the MIDCAB procedure for repeat CABG have been reported [10, 11]. For the MIDCAB operation, the IMA can be dissected using thoracoscopy, and good results have been reported [6, 8, 13, 14]. We define a VADCAB procedure as a combination of video thoracoscopic IMA harvest and direct CABG through an anterior minithoracotomy (5 to 8 cm in length, with or without rib resection) without cardiopulmonary bypass. This procedure is minimally invasive in a true sense.

Thoracoscopic IMA harvest
We [13, 14] have reported excellent results of thoracoscopic IMA harvest using the Harmonic Scalpel. The thoracoscopic procedure allows excellent visualization of the IMA and thus facilitates mobilization of the pedicle from the upper margin of the first rib or higher to the fifth or sixth rib. This provides sufficient length for a tension-free anastomosis to the midpoint of the LAD or sometimes more distally. In 5 (71%) of 7 patients who needed revascularization of both the LAD and a diagonal branch, the IMA graft was long enough for sequential anastomoses. With the Harmonic Scalpel, coagulation and division of the tissues are accomplished with much less heat than electrocautery, very little vapor or smoke, and no skeletal muscle stimulation. A VADCAB procedure was attempted in 73 patients and successfully performed in 70 (95.9%). It failed in 3 patients because of poor blood flow in the LIMA (2) and complete pleural symphysis precluding thoracoscopic LIMA harvest (1). The 2 patients with unsuitable LIMAs underwent MIDCAB with a saphenous vein graft, and the patient with pleural symphysis had MIDCAB using an H graft [15].

Surgical results of VADCAB
Since November 1995, 110 patients have had a MIDCAB procedure in our institution. Of these patients, 70 (64%) had a VADCAB procedure. The other 40 patients underwent a MIDCAB operation as follows: gastroepiploic artery to posterior descending artery or RCA, 16; saphenous vein or radial artery as a free graft, 11; IMA to LAD using a sternotomy, 6; IMA to LAD using a thoracotomy, 3; LIMA to LAD + RIMA to RCA using a thoracotomy and partial sternotomy, 2; and H-graft procedure, 2. We reviewed the charts of these 70 VADCAB patients and compared their results with those of patients who underwent conventional single or double CABG using the IMA as a pedicle graft between 1993 and 1995 and could have been VADCAB candidates retrospectively. The mortality, morbidity, and postoperative intensive care unit stay for the VADCAB group and the conventional CABG group were similar. However, the number of patients who needed postoperative positive inotropic agents, the intubation time, and the duration of hospital stay in the conventional CABG group were significantly greater than those in the VADCAB group, although the latter included more high-risk patients. The mean follow-up for the VADCAB patients was 13.9 months. For 36 grafts in 35 patients, 6-month follow-up Doppler assessment (31 patients) or coronary angiography (4 patients) showed 35 grafts patent (97.2%).

	Conclusions

Top Abstract Introduction Material and methods Results Comment Conclusions References

 
The VADCAB procedure, a combination of thoracoscopic IMA harvest and direct CABG through a minithoracotomy without cardiopulmonary bypass is less invasive than conventional CABG. Surgical results with the VADCAB procedure were better than those with conventional CABG in this review, although the VADCAB group included more high-risk patients than the conventional CABG group.

	References

Top Abstract Introduction Material and methods Results Comment Conclusions References

 

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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Kagami Miyaji Randall K. Wolf John B. Flege, Jr Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Miyaji, K. Articles by Flege, J. B. Search for Related Content PubMed PubMed Citation Articles by Miyaji, K. Articles by Flege, J. B., Jr