The axillocoronary bypass. Blood flow and short-term graft histology in a porcine model.

BACKGROUND: Bypass grafts arising from the axillary artery may be indicated for complications during minimally invasive direct coronary artery bypass grafting, for redo operations and for management of a severely atherosclerotic ascending aorta. As basic data research on this technique is scanty, we investigated intraoperative function and postoperative morphology of axillocoronary bypass grafts in a porcine model. METHODS: Thirteen German domestic pigs received an axillocoronary vein graft (Group I, n=7) or an aortocoronary vein graft (Group II, n=6) to the left anterior descending artery. In Group I the proximal anastomosis was performed to the left axillary artery, and after partial rib resection the graft was brought transpleurally to the target vessel. In both groups the coronary anastomosis was carried out on the beating heart without cardiopulmonary bypass. Graft flow was measured using transit time ultrasonic flow probes. RESULTS: Intraoperatively all grafts showed a typical diastolic flow profile. Stable graft flow was lower in axillocoronary bypass grafts: 47 (30-60 mL/min) in Group I and 65 (35-126 mL/min) in Group II (p=0.005). Flow given as percentage of cardiac output, however, did not differ between the two grafts: 0.9 (0.6-1.2%) in Group I and 1.2 (0.8-2.4%) in Group II (p=NS). At day 4 after surgery there was no clear histologic predilection site for microtrauma and early degenerative changes in the axillocoronary graft. CONCLUSIONS: Axillocoronary bypass flow compares well with flow in the aortocoronary graft. Microtrauma after implantation and early degenerative changes in the axillocoronary vein bypass are not particularly impacted by the thoracic entry site.

Risk assessment in genetics: a semi-quantitative approach.

Public awareness of genetic predisposition to diseases such as breast cancer threatens to put severe strain on genetics services. Computer-based decision support for general practitioners (GPs) has the potential to reduce unnecessary referrals, but issues of communicating about levels of risk and uncertainty must be addressed. An argumentation logic formalism can subsume both traditional probability theory and more qualitative, reason-based approaches to communicating uncertainty, and we propose that qualitative, argument-based presentation will make uncertainty information more accessible and comprehensible to both patient and GP. We describe software that uses an argumentation approach to assess genetic risk during a GP consultation and provide referral advice along with detailed qualitative explanations for its advice. The software was evaluated in real-life GP consultations in which actors played patients concerned about genetic risk, and in use by GPs evaluating simulated cases. Significant improvement in accuracy of assessment and appropriateness of referrals was found. GPs viewed the software and the qualitative reporting approach highly favourably.

RAGs: A novel approach to computerized genetic risk assessment and decision support from pedigrees.

OBJECTIVES: To assist general practitioners in evaluating patients' genetic risk of cancer on the basis of family history data. METHODS: A new computer application, RAGs (Risk Assessment in Genetics), has been developed to help doctors create graphical family trees and assess the genetic risk of breast and colorectal cancer. RAGs possesses two features that distinguish it from similar software: (i) a user-centred design, which takes into account the requirements of the doctor-patient encounter; (ii) effective and accessible risk reporting by employing qualitative evidence for or against increased risk, which is more easily understood than numerical probabilities. The system allows any rule-based genetic risk guideline to be implemented, and may be readily modified to cater for the varying degrees of information required by different specialists. RESULTS: RAGs permits fast, accurate data entry, and results in more appropriate management decisions than those made via other techniques. In addition, RAGs enables both the clinician and the patient to understand how it arrives at its conclusions, since the use of qualitative evidence allows the program to provide explanations for its reasoning. CONCLUSIONS: The RAGs system promises to help practitioners be more effective gatekeepers to genetic services. It may empower doctors both to make an informed choice when deciding to refer patients who are at increased genetic risk of breast or colorectal cancer, and to reassure those who are at low risk.

Minimally invasive subclavian/axillary artery to coronary artery bypass (SAXCAB): review and classification.

BACKGROUND AND PURPOSE: Subclavian/axillary artery to coronary artery bypass (SAXCAB) surgery is defined as a minimally (or less) invasive coronary revascularization procedure where one or more grafts are anastomosed to the second or third parts of the subclavian artery or any of the three parts of the axillary artery (inflow source) and attached to one or more coronary arteries, and where there are two separate minimally invasive incisions to expose the target coronary artery and the inflow sources, respectively. The indications and contraindications for SAXCAB surgery are discussed, and the relevant chest wall anatomy and that of the subclavian and axillary arteries are reviewed. The effect of respiration and anatomic variability as they impact the SAXCAB graft are discussed. Three components of the anatomy that are important in SAXCAB surgery are discussed: The relation of the first rib to the clavicle insofar as it affects access to the third part of the subclavian artery, the anatomy of the subclavian and axillary arteries and their branches, and the anatomy of the chest wall and its movement. In addition, the different SAXCAB variations that have been applied clinically are reviewed and classified, and future aspects of SAXCAB research are discussed. SAXCAB surgery is unique among the different types of minimally invasive direct coronary artery bypass (MIDCAB) surgery because of the enormous diversity of the techniques that have been described. Based on these descriptions, a new classification of SAXCAB grafting is proposed depending on whether the graft is inside or outside the rib cage and whether or not the coronary artery is exposed by rib resection or through an intercostal space. The third part of the classification takes into consideration the mode of entry into the chest, whether it is by rib resection or through an intercostal space. METHODS: Inquiries were made by telephone and by mail in the year 2000 to a number of surgeons who had published details of their SAXCAB techniques, and informal information was obtained by a series of personal communications as to the estimated number of operations they had performed and the outcomes. Published data was also used to formulate a rough guide as to the international status of the procedure at this time. RESULTS: The total estimated international experience is about 100 cases and the patency is between 70 and 100 percent in the time frame of about one to two years. CONCLUSIONS: The MIDCAB technique in general has been successful in providing an alternative way to revascularize the coronary arteries, and the SAXCAB has proved to be one of the most interesting classes of MIDCAB surgery. SAXCAB grafts seem to be unique among coronary revascularization procedures and, indeed, probably almost all vascular procedures, in that there is enormous diversity in the route for the graft from the inflow source to the target coronary artery. Being knowledgeable about the different varieties of SAXCAB surgeries will help the surgeon during a rescue operation as the surgery can be tailored to suit a particular patient. The SAXCAB seems to be a very safe operation, and it is striking that so far no one has reported any major complications.

The subclavian and axillary arteries as inflow vessels for coronary artery bypass grafts--combined experience from three cardiac surgery centers.

BACKGROUND: The subclavian and axillary arteries represent reliable inflow vessels in peripheral vascular surgery. During recent years they have also been used for special situations in coronary artery bypass grafting. We report on a preliminary, triple center experience with subclavian/axillary artery to coronary artery bypass grafting. METHODS: Twenty-one patients (11 male, 10 female, median age 70 years) received subclavian artery/axillary artery to coronary artery bypass grafts. Indications for application of this bypass variation were internal mammary artery problems during minimally invasive coronary artery bypass grafting (n = 10), untouchable ascending aorta (n = 6), high risk reoperations (n = 3), severe chronic obstructive pulmonary disease (COPD) (n = 1) and right ventricular ischemia after ascending aortic replacement for acute aortic dissection type A (n = 1). Fourteen procedures were carried out via minithoracotomy, and seven via sternotomy. Inflow vessels were the left subclavian/axillary artery in 12 cases, the right subclavian/axillary artery in eight cases and bilateral subclavian/axillary artery in one case. Bypass conduits were the saphenous vein (n = 20 for revascularization of the left anterior descending artery, the right coronary artery and obtuse marginal branches) and the radial artery (n = 2 for revascularization of diagonal branches). RESULTS: The procedure was without major technical problems in all patients. Hospital mortality was 1/21. Neither brachial plexus injury nor arm ischemia occurred. Mean pre- and postoperative angina classification was 3.0 +/- 0.8 and 1.2 +/- 0.4 respectively (p < 0.001). After a mean follow-up period of seven months, one out of 14 axillocoronary vein grafts studied by ultrasonic duplex scan or angiography was found occluded. Graft patency could be demonstrated for an observation period of up to two years. CONCLUSION: Subclavian/axillary artery to coronary artery bypass is feasible and can be applied for complications in minimally invasive coronary artery bypass grafting, for redo operations and for management of the severely atherosclerotic ascending aorta. To reach the left anterior descending artery-system, the saphenous vein as well as the radial artery can be used. Complications concerning the infraclavicular incision seem to be no problem. Short-term patency rates are acceptable.

Minimally invasive reoperation through a lateral thoracotomy for circumflex coronary artery bypass.

We report 4 cases of redo coronary artery bypass grafting in which the circumflex coronary artery was successfully revascularized using a minimally invasive approach. In reoperative cases, it is easier to approach the circumflex coronary artery from the left side than from the front. Minimally invasive direct coronary artery bypass technology has made it possible to avoid using cardiopulmonary bypass. In our 4 cases, the revascularization procedure was performed via a small left thoracotomy, and without cardiopulmonary bypass. The patients made a good recovery and are free of angina 22 months after operation. We conclude that the thoracotomy approach provides the opportunity to avoid several hazards: a redo sternotomy, dissection of a hostile mediastinum, and manipulation of the heart.

Minimally invasive coronary bypass surgery: postoperative pain management using intermittent bupivacaine infiltration.

Minimally invasive direct coronary artery bypass grafting (MIDCAB) is becoming a popular adjunct to standard cardiac bypass surgery in selected patients with accessible single or double vessel disease. However, the limited anterior thoracotomy used to access the heart involves trauma to the muscle tissue during removal of the fourth costal cartilage and a small piece of connected rib, perhaps leading to more severe postoperative pain compared with patients undergoing routine sternotomy. Intrathecal opioids can be used but have limited therapeutic duration and there is concern regarding anticoagulation. We present a case where soft tissue catheters were placed into the depths of the surgical wounds and pain was diminished greatly by intermittent regular infiltration with bupivacaine.

The "T-MIDCAB" procedure. Use of extension grafts from the undisturbed internal mammary artery in high-risk patients.

BACKGROUND: Minimally invasive direct coronary artery bypass grafting (MIDCAB) is an attractive new alternative for revascularizing patients with high perioperative risk for standard coronary surgery. However, limited surgical exposure through a small thoracotomy makes harvesting the full length of the internal mammary artery (IMA) very difficult and time consuming. We are now employing a new alternative with a "T" shaped bridge graft constructed from the undisturbed IMA using a 4 centimeter interposition segment of donor vessel. We prefer this approach in high risk cases in order to reduce the trauma of the thoracotomy, minimize pain and narcotic use, promote early extubation, and achieve immediate post-operative mobilization and recovery in patients who would otherwise be at risk for a poor outcome with conventional grafting techniques. METHODS: From September 10, 1997 to December 19, 1997 eight high-risk patients underwent at least one "T-MIDCAB" graft from the undisturbed IMA to the coronary artery using a short segment of either radial artery or saphenous vein. All cases were performed using a limited access anterior thoracotomy through the bed of the resected costal cartilage and without intercostal retraction. Five males and three females ranging from 58 to 83 years (average 73 years) were operated using this new concept. Pre-operative ejection fractions ranged from 25% to 80% (mean 43%). Parsonnet scores ranged from 21 to 43 (average 34) with predicted mortalities ranging from 30 to 40%. RESULTS: Eleven "T" grafts were placed (1.38 distals/patient). All 8 patients survived. Postoperative complications were minimal. The average length of stay was only 8 days (range 3 to 9 days). Intensive care unit stay averaged 3 days (range 1 to 4 days). One patient underwent postoperative angiography which demonstrated full patency of the conduit and all anastomoses. CONCLUSIONS: "T-MIDCAB" using a bridge graft of free radial artery or saphenous vein appears to be successful in high risk patients. The authors noted shorter operative times, reduced chest wall trauma and better pain control than with standard MIDCAB and full IMA harvesting. Cautious use of this procedure as an alternative to more morbid types of surgical revascularization is advised.

Minimally invasive direct coronary artery bypass surgery.

Traditional coronary artery bypass surgery involves a median sternotomy and the use of a heart-lung machine to stabilize the heart during suturing. Minimally invasive coronary artery surgery employs small incisions directly over the target vessels and avoids the use of a heart-lung machine, which can cause postoperative complications. The target coronary vessels are stabilized in alternative ways, potentially hazardous manipulation of the ascending aorta is avoided, and the subclavian and axillary arteries provide alternative inflow sources. Other new techniques used in minimally invasive procedures include a coronary artery cannula to avoid intraoperative ischemia and wound irrigation catheters to administer postoperative bupivacaine hydrochloride. Perioperative nurses need to become familiar with these new techniques to be able to plan and implement effective patient care.

Arrhythmia/ischemia management during minimally invasive cardiac operation.

We present a case of severe arrhythmia and hemodynamic compromise in a patient undergoing minimally invasive coronary artery bypass grafting without cardiopulmonary bypass. This was successfully treated via an extracorporeal shunt from a femoral artery cannula.

Detection of Chlamydia pneumoniae in atherosclerotic plaques in the walls of arteries of lower extremities from patients undergoing bypass operation for arterial obstruction.

PURPOSE: To study surgically excised vascular tissue from lower extremities for the presence of Chlamydia pneumoniae, to extend the previously described association of the organism with atherosclerosis. METHODS: Arterial biopsy specimens obtained from femoral and popliteal arteries during bypass operation for claudication were examined by immunocytochemical analysis and polymerase chain reaction for the presence of organisms. RESULTS: C. pneumoniae was detected in atherosclerotic plaques by either method in either artery of 11 of 23 patients (48%). Eight of 21 popliteal and three of 18 femoral arteries had positive results. CONCLUSIONS: Detection of C. pneumoniae in peripheral arteries indicates that the organism is widespread in atherosclerosis of the vascular system.