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Ann Thorac Surg 1997;64:1725-1727
© 1997 The Society of Thoracic Surgeons

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Original Articles: Cardiovascular

Intraoperative Angiography During Minimally Invasive Direct Coronary Artery Bypass Operations

Division of Cardiac Services, St. Charles Medical Center, Bend, Oregon

Accepted for publication June 11, 1997.

	Abstract

Top Footnotes Abstract Introduction Material and Methods Results Comment References

 
Background. The technical demands of beating heart operations raise concerns about anastomotic patency. This feasibility study tested the usefulness of intraoperative angiography during minimally invasive direct coronary artery bypass grafting (MIDCABG).

Methods. Ten patients underwent intraoperative angiography of the internal thoracic artery (ITA) after MIDCABG. Minimally invasive direct coronary artery bypass grafting was performed on a beating heart through the fourth or fifth intercostal space. Angiography was performed through the right or left femoral artery with a 7F introducer system placed before the operation. Views were obtained in the right and left anterior oblique and straight anterior projections.

Results. There were no deaths or intraoperative morbidities related to MIDCABG or angiography. Seven patients demonstrated widely patent MIDCABG anastomoses with obliteration of all intercostals, widely patent ITA pedicles, good distal runoff, and placement of the ITA into the proper native coronary artery. Two patients had revisions of their ITA pedicles, which on repeated angiography showed correction. One patient's procedure was converted to a sternotomy because of poor distal runoff and haziness at the level of the MIDCABG anastomosis.

Conclusions. This feasibility study demonstrates the utility of intraoperative ITA angiography in identifying problems after MIDCABG. Intraoperative angiography may facilitate MIDCABG by documenting proper placement of conduits, obliteration of intercostal vessels, and patency of the MIDCABG anastomosis and ITA pedicle.

	Introduction

Top Footnotes Abstract Introduction Material and Methods Results Comment References

 
Minimally invasive direct coronary artery bypass grafting (MIDCABG) is evolving rapidly as a new arterial revascularization technique [1, 2]. The most common conduit used is the internal thoracic artery (ITA) anastomosed to the left anterior descending artery (LAD). This combination of arterial conduit and native coronary anastomosis has been shown in long-term follow-up to be the most important predictor of patient survival after coronary artery bypass grafting [3]. The technique of MIDCABG relies on the ability of a surgeon to operate successfully on a beating heart. The increased technical demands of beating heart operations raise concerns regarding the short- and long-term patency of the ITA–LAD anastomosis [4]. Recent technologic advances in MIDCABG instrumentation, particularly the ability to stabilize the epicardium at the site of the anastomosis, are reducing the technical demands of beating heart operations [5]. Documentation of anastomotic patency, even with improvements in technology, is essential. Attempts to use nonanatomic, nonangiographic, physiologic measurements to document patency (eg, Doppler velocity, thermal imaging, flow volume) lack validity and have not been substantiated by large, comparative, prospective studies in the literature. In addition, nonangiographic methods lack the ability to define the source of a problem anatomically. Patency of the ITA– LAD anastomosis and pedicle is an anatomic characteristic that is defined best by angiography. The purpose of this study was to test the feasibility and usefulness of intraoperative ITA angiography during MIDCABG.

See also pages 1835 and 1840.

	Material and Methods

Top Footnotes Abstract Introduction Material and Methods Results Comment References

 
Between November 1996 and March 1997, 10 patients underwent MIDCABG at Saint Charles Medical Center in Bend, Oregon. Patients were offered the choice of MIDCABG or standard ITA–LAD bypass in conjunction with an institutional review board–approved protocol. Nine patients underwent elective MIDCABG and 1 patient underwent emergency MIDCABG within 12 hours of an acute myocardial infarction. A specialized retractor system to facilitate ITA takedown and reduce movement at the site of the ITA–LAD anastomosis (Cardiothoracic Systems Inc, Cupertino, CA) was used in all 10 cases. Before this time, MIDCABG had been performed at our institution using "off-the-shelf" materials, but this practice was discontinued because of concerns regarding anastomotic patency compared with standard bypass techniques.

Minimally invasive direct ITA–LAD bypass was performed through a small left anterior thoracotomy with the patients supine. The patients were prepared and draped for conventional bypass operation. An 8- to 12-cm incision was made and the ITA was identified through the fourth or fifth intercostal space. The pericardium then was opened to identify the LAD. Takedown of the ITA ensued. Anastomosis of the ITA to the LAD was completed and intraoperative ITA angiography was performed by a cardiologist to document proper placement of the ITA into the targeted native coronary artery, ligation of all intercostal arteries, and patency of the ITA–LAD anastomosis and pedicle. Patency was defined as less than a 50% stenosis in two angiographic views. A femoral artery introducer system was placed (7F USCI #07001; Bard, Inc, Billerica, MA) after the induction of anesthesia. An ITA catheter (7F #010371; Bard, Inc) and a 0.032-in x 145-cm, 3-mm "J" guidewire (USCI #007042, Bard, Inc) were used to intubate the ITA ostia.

Using a C-arm fluoroscopy device (Phillips Medical Systems North America, Shelton, CT), right and left anterior oblique and straight anterior views of the ITA and the ITA–LAD anastomosis were obtained using contrast medium (iohexol, 350 mg/mL; Nycomed, Inc, Princeton, NJ). Permanent views were obtained and used along with immediate real-time fluoroscopic examination to ascertain pedicle and ITA–LAD patency. Recently (patient 10), we have begun to use a C-arm fluoroscopy system that has digital storage capacity and improved intraoperative resolution and playback capabilities (OEC Medical Systems, Salt Lake City, UT).

	Results

Top Footnotes Abstract Introduction Material and Methods Results Comment References

 
There were no intraoperative deaths or morbidities. No angiographic procedures exceeded 15 minutes in duration. There were no cardiac deaths. There was 1 late death after hospital discharge caused by stroke in an elderly patient who underwent successful MIDCABG and was awaiting elective carotid endarterectomy. Three patients required surgical reintervention on the basis of intraoperative angiographic findings. Two patients had a lesion (a kink proximal to the patent anastomosis) in the ITA pedicle that was corrected immediately by repositioning the pedicle through the thoracotomy incision (Fig 1). The third patient required conversion of the procedure to a sternotomy and revision of the ITA–LAD anastomosis because of poor runoff into the LAD, a large remaining first intercostal branch, and haziness at the level of the anastomosis. A discrete anastomotic problem was not visualized, but the resolution of the stored anastomotic views was less than optimal. Because of subtle findings of poor runoff, haziness at the level of the anastomosis, and a patent first intercostal branch, we believed that the patient would be served best by revising the pedicle and anastomosis on bypass.

View larger version (128K): [in this window] [in a new window]   Fig 1. . Angiographic demonstration of internal thoracic artery pedicle malposition resulting in a lesion (kink) proximal to the anastomosis. The anastomosis is patent. Lengthening and repositioning of the pedicle through the initial thoracotomy incision corrected the problem.

	Comment

Top Footnotes Abstract Introduction Material and Methods Results Comment References

There are several technical factors that affect immediate patency. On the basis of current technology and research, the gold standard is the ITA–LAD anastomosis performed using cardiopulmonary bypass and one of a number of myocardial protective techniques. Given that the ITA–LAD anastomosis is the most important in coronary artery bypass grafting, MIDCABG is a new and more technically demanding technique than conventional coronary artery bypass grafting, and angiography is the gold standard for determining ITA–LAD patency, intraoperative angiography should be used in a strict protocol fashion to document the patency of the ITA–LAD anastomosis after MIDCABG. Intraoperative angiography has the advantages of allowing immediate surgical reintervention and reducing the need for additional cardiac catheterizations and other procedures during the same hospitalization.

This study revealed pedicle and anastomotic problems that may not have been evident by other clinical means before the patient left the operating room. The results for the patient would have been less than optimal, and they may have been life-threatening. Before exiting the operating room, the surgeon must be certain that the MIDCABG ITA–LAD anastomosis is patent, and if not, that a satisfactory and equally efficacious alternative is available to the patient. Intraoperative angiography was completed within 15 minutes in all cases. This period includes the time required for the placement of equipment and the performance of fluoroscopy.

The initial quality of the stored angiographic pictures using standard C-arm fluoroscopy equipment was less than satisfactory in the first 9 patients. The resolution of the stored pictures was poor for defining discrete lesions, prompting us to convert 1 case on the basis of poor distal runoff into the proximal and distal LAD as seen on the real-time fluoroscopic images. Angiographic lesions in the pedicle were visualized easily during real-time fluoroscopy, but stored views also were less than optimal. Currently, our angiographic equipment has been upgraded to a high-resolution digital system with immediate playback capabilities that has eliminated these problems. In our current protocol, the initial intraoperative angiographic view defines the patency of the ITA pedicle and the obliteration of intercostal vessels using an anteriorly directed image. Subsequent views in the left and right anterior oblique projections define anastomotic patency, distal and proximal runoff, graded flow, and proper placement of the conduit in the correct location (ie, on and in the native coronary artery). Comparative and validation studies with cardiac catheterization laboratory-based technology currently are under way.

This small feasibility study indicates that intraoperative angiography can be performed satisfactorily and allows immediate visualization of the MIDCABG ITA–LAD takedown and anastomotic technique and, if required, immediate reintervention to ensure optimal results (ie, angiographic patency before leaving the operating room). Intraoperative angiographic studies can serve as a basis for long-term angiographic studies and reduce the need for and cost of cardiac catheterization after MIDCABG. Currently at our institution, the development and availability of newer, portable angiographic equipment has provided better resolution and storage capacity and improved critical evaluation by surgeons and cardiologists of ITA–LAD MIDCABG. Intraoperative angiography coupled with long-term angiographic follow-up will help define the place of MIDCABG in the surgical armamentarium.

	Footnotes

Top Footnotes Abstract Introduction Material and Methods Results Comment References

 
Address reprint requests to Dr Lazzara, 1501 NE Medical Center Dr, Bend, OR 97701 (e-mail: hsurg{at}aol.com).

Doctor Lazzara is a member of the Scientific Advisory Board for and holds stock options with Cardiothoracic Systems, and Dr McLellan is an advisory consultant. Both Dr Lazzara and Dr McLellan have received financial compensation from Cardiothoracic Systems in the form of honoraria and expenses. Doctor McLellan has also received similar compensation from OEC Medical Systems, Salt Lake City, UT. St. Charles Medical Institution also serves as a teaching and educational center for Cardiothoracic Systems, for which it receives financial compensation.

	References

Top Footnotes Abstract Introduction Material and Methods Results Comment References

 

1. Subramanian VA, Sani G, Benetti FJ, Calafiore AM. Minimally invasive coronary bypass surgery: a multi-center report of preliminary clinical experience. Circulation 1995;92(Suppl 1):645.
2. Emery RW, Emery AM, Flavin TF, Nissen MD, Mooney MR, Arom KV. Revascularization using angioplasty and minimally invasive techniques documented by thermal imaging. Ann Thorac Surg 1996;62:591–3.[Abstract/Free Full Text]
3. Cameron A, Davis G, Schaff HV. Coronary bypass surgery with internal thoracic artery grafts: effects on survival over a 15 year period. N Engl J Med 1996;334:220–5.[Abstract/Free Full Text]
4. Westaby SW, Benetti FJ. Less invasive coronary surgery: consensus from the Oxford meeting. Ann Thorac Surg 1996;62:924–31.[Free Full Text]
5. Boonstra PW, Grandjean JG, Mariani MA. Improved method for direct coronary grafting without CPB via an anterolateral small thoracotomy. Ann Thorac Surg 1997;63:567–9.[Abstract/Free Full Text]

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This Article Abstract 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): Robert R. Lazzara Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lazzara, R. R. Articles by Young, E. K. Search for Related Content PubMed PubMed Citation Articles by Lazzara, R. R. Articles by Young, E. K. Related Collections Related Articles