Practice improves performance on a coronary anastomosis simulator, attending surgeon supervision does not.

OBJECTIVES: Enthusiasm for simulation early in cardiothoracic surgery training is growing, yet evidence demonstrating its utility is limited. We examined the effect of supervised and unsupervised training on coronary anastomosis performance in a randomized trial among medical students. METHODS: Forty-five medical students were recruited for this single-blinded, randomized controlled trial using a low-fidelity simulator. After viewing an instructional video, all participants attempted an anastomosis. Subsequently, the participants were randomized to 1 of 3 groups: control (n = 15), unsupervised training (n = 15), or supervised training with a cardiothoracic surgeon or fellow (n = 15). Both the supervised and unsupervised groups practiced for 1 hour per week. After 4 weeks, the participants repeated the anastomosis. All pre- and posttraining performances were videotaped and rated independently by 3 cardiothoracic surgeons blinded to the randomization. All raters scored 13 assessment items on a 1 to 5 (low-high) scale along with an overall pass/fail rating. RESULTS: After the training period, all 3 groups showed significant improvements in composite scores (control: +0.52 ± 0.69 [P = .014], unsupervised: +1.05 ± 0.48 [P < .001], and supervised: +1.10 ± 0.84 [P < .001]). Compared with control group, both supervised (P = .005) and unsupervised trainees (P = .005) demonstrated a significant improvement. Between the supervised and unsupervised groups there were no statistically significant differences in composite scores. CONCLUSIONS: Practice on low-fidelity simulators enabled trainees to improve on a broad range of skills; however, the additional effect of attending-level supervision is limited. In an era of increasing staff surgeon responsibilities, unsupervised practice may be sufficient for inexperienced trainees.

Acute kidney injury after cardiac surgery: is minocycline protective?

BACKGROUND AND OBJECTIVES: Acute kidney injury (AKI) after cardiac bypass surgery (CABG) is common and carries a significant association with morbidity and mortality. Since minocycline therapy attenuates kidney injury in animal models of AKI, we tested its effects in patients undergoing CABG. DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS: This is a randomized, double-blinded, placebo-controlled, multi-center study. We screened high risk patients who were scheduled to undergo CABG in two medical centers between Jan 2008 and June 2011. 40 patients were randomized and 19 patients in each group completed the study. Minocycline prophylaxis was given twice daily, at least for four doses prior to CABG. Primary outcome was defined as AKI [0.3 mg/dl increase in creatinine (Cr)] within 5 days after surgery. Daily serum Cr for 5 days, various clinical and hemodynamic measures and length of stay were recorded. RESULTS: The two groups had similar baseline and intra-operative characteristics. The primary outcome occurred in 52.6% of patients in the minocycline group as compared to 36.8% of patients in the placebo group (p = 0.51). Peak Cr was 1.6 ± 0.7 vs. 1.5 ± 0.7 mg/dl (p = 0.45) in minocycline and placebo groups, respectively. Death at 30 days occurred in 0 vs. 10.5% in the minocycline and placebo groups, respectively (p = 0.48). There were no differences in post-operative length of stay, and cardiovascular events between the two groups. There was a trend towards lower diastolic pulmonary artery pressure [16.8 ± 4.7 vs. 20.7 ± 6.6 mmHg (p = 0.059)] and central venous pressure [11.8 ± 4.3 vs. 14.6 ± 5.6 mmHg (p = 0.13)] in the minocycline group compared to placebo on the first day after surgery. CONCLUSIONS: Minocycline did not protect against AKI post-CABG.

Conduits for coronary bypass: strategies.

Strategic planning is integral to any operation but complexity varies immensely and therefore the effort necessary to create the optimal plan. The previous three reports have discussed individual conduits and herein is an attempt to present approaches to common situations which the author favors. Although much has been learned over 45 years about use and subsequent behavior of venous and arterial grafts we continue to learn and, as a result, evolve new strategies or modify those now popular. Thus the reader must recognize that in spite of trying to be balanced and inclusive all surgeons have personal opinions and also prejudices which influence the approach taken and which may not be the optimal one for others or for the patient.

Conduits for Coronary Bypass: Arteries Other Than the Internal Thoracic Artery's.

This is the third in a series on coronary artery bypass which reviews three alternative arterial conduits. The radial artery has become the most widely used of the three and accumulating experience demonstrates better patency at 10 years versus saphenous vein. Drawbacks are a long incision on the forearm, the propensity for spasm and persistent sensory disturbance in about 10%. The first is answered by endoscopic harvest which may yield a shorter conduit but reduces sensory nerve injury. Spasm is managed pharmacologically and by less harvest trauma. The gastroepiploic artery is used in situ and free and although the abdominal cavity is entered complications are minimal and patency compares favorably with the radial artery. Use of the inferior epigastric artery remains minimal and its similar length often requires composite use but limited patency data are supportive. Other arteries have had rare use and this is unlikely to change because the three presented here have significant advantages and acceptance.

Conduits for coronary bypass: vein grafts.

The saphenous vein has been the principal conduit for coronary bypass grafting from the beginning, circa 1970. This report briefly traces this history and concomitantly presents one surgeons experience and personal views on use of the vein graft. As such it is not exhaustive but meant to be practical with a modest number of references. The focus is that of providing guidance and perspective which may be at variance with that of others and recognizing that there may be many ways to accomplish the task at hand. Hopefully the surgeon in training/early career may find this instructive on the journey to surgical maturity.

Radial artery free and T graft patency as coronary artery bypass conduit over a 15-year period.

BACKGROUND: The radial artery is often used as the second arterial graft for coronary artery bypass grafting. Little is known about the differences in long-term patency between radial free and T grafts. This study was performed to determine long-term radial artery patency over a 15-year period. METHODS AND RESULTS: Radial arteries were used as free grafts or T grafts for coronary artery bypass grafting over a 15-year period. Patients were contacted to determine if postoperative cardiac catheterization was performed and examination of any reports and films was performed. Grafts were graded as patent, luminal irregularity, or occluded. Each sequential graft was counted separately. Between September 1993 and December 2008, 13,926 patients underwent isolated coronary artery bypass grafting and 3248 patients had at least one radial artery graft used as a conduit. Catheterizations were performed at a mean of 7.4 ± 3.8 years (range, 3 days to 14.4 years) on 372 radial artery grafts (103 free and 269 T) in 215 patients. Kaplan-Meier freedom from occlusion for radial free and T grafts at 1 and 10 years was 97.1% and 75.4% and 99.6% and 62.9%, respectively (P=0.146 free versus T). Kaplan-Meier survival to 15 years was not statistically different between free and T graft patients (P=0.5). CONCLUSIONS: In 215 patients with postoperative catheterization after coronary artery bypass grafting with a radial artery graft, radial free and T grafts had similar and acceptable long-term patency to support their use as a coronary artery bypass graft conduit.

Conduits for coronary bypass: internal thoracic artery.

This second report in the series on coronary artery bypass presents the authors experience and personal views on the internal thoracic artery (ITA) which date to 1966. There has been a very gradual evolution in the acceptance of this conduit which was initially compared with the saphenous vein and viewed as an improbable alternative to it. As is common with concepts and techniques which are 'outside the box' there was skepticism and criticism of this new conduit which was more difficult and time consuming to harvest for the surgeon who had to do it all. It was viewed as small, fragile, spastic and its flow capacity was questioned. Only a few surgeons employed it because of these issues and some of them would frequently graft it to the diagonal artery as it was thought not to supply adequate flow for the left anterior descending unless it was small. After a decade, angiographic data revealed superior patency to vein grafts. Even this evidence and survival benefit reported a few years later did not convince many surgeons that their concerns about limitations justified its use. Thus widespread adaption of the ITA as the conduit of choice for the anterior descending required another decade and bilateral use is only now expanding to more than 5% of patients in the US and somewhat faster in other countries.

Abdominal wall necrosis after harvest of both internal thoracic and inferior epigastric arteries.

BACKGROUND: The internal thoracic artery (ITA) and inferior epigastric artery (IEA) may be used as conduits for myocardial revascularization. Harvesting the ITAs and IEAs can lead to clinically significant ischemia of the anterior abdominal wall. METHODS: We created a registry with data from 108 patients receiving myocardial revascularization with 1 or greater ITA and (or) 1 or greater IEA. After revascularization, patients were followed to document their outcomes during hospitalization. We sought to identify risk factors for tissue necrosis in these patients. RESULTS: All patients had 1 (84%) or 2 (16%) IEAs harvested. Both ITAs were utilized in 81% of patients; 19% had only the left ITA harvested. All patients in whom 2 IEAs were harvested also had 2 ITAs harvested (17 of 108). Of these 17 patients, 2 (12%) developed abdominal wall necrosis. Only patients who had bilateral ITA and bilateral IEA harvest experienced this complication. CONCLUSIONS: Bilateral harvest of ITAs and IEAs results in a moderate risk of clinically significant abdominal wall necrosis. The extent of tissue loss may involve skin, muscle, and fascia, but the peritoneum and posterior rectus sheath remained intact in both affected patients in this series. These data may be most valuable to those who contemplate an abdominal operation in a patient who has had one or more of their ITAs or IEAs taken.

Absence of deterioration of vascular function of the donor limb at late follow-up after radial artery harvesting.

OBJECTIVE: Radial artery harvesting has been questioned because of purported long-term circulatory consequences. Previous midterm Doppler ultrasonographic results are inconsistent regarding ulnar arterial effects. Flow-mediated vasodilatation more sensitively measures response to shear stress as index of arterial reactivity and function. METHODS: We contacted 231 patients who had undergone radial artery harvesting at least 10 years previously (mean follow-up, 12.9 ± 0.8 years). Subcohort of 25 volunteers (mean age, 69.2 ± 8.4 years) underwent ultrasonographic evaluation of ipsilateral (harvest) and contralateral (control) ulnar arteries. Flow-mediated vasodilatation compared changes in ulnar arterial diameters before and after occlusion. RESULTS: In subcohort, peak systolic velocity of harvest ulnar artery was 0.82 ± 0.15 m/s, versus 0.63 ± 0.23 m/s on control side (P < .001), with no differences in intimomedial thickness (P = .763) or presence of atherosclerotic plaques (P = .364). Baseline diameter of harvest ulnar artery was 3.0 ± 0.5 mm, versus 2.7 ± 0.6 mm on control side (P = .007). Postocclusion diameter of harvest ulnar artery was 3.2 ± 0.5 mm, versus 2.9 ± 0.6 mm on control side (P = .001). No differences were seen in preocclusion and postocclusion absolute and percentage changes in ulnar arterial diameter (Table 1). CONCLUSIONS: Despite increased shear stress, no deterioration in either ulnar arterial structure or functional reactivity was measured by flow-mediated vasodilatation more than 10 years after radial artery harvesting. With appropriate preoperative evaluation, radial arterial grafting for coronary artery bypass grafting is not associated with long-term donor limb vascular insufficiency.

Operative treatment of coronary atherosclerosis.

The evolution of percutaneous intervention has reduced the prevalence of coronary bypass surgery in a patient population that is older, with more comorbidity and advanced coronary disease. Despite this less favorable group, perioperative mortality has continued to decline as the operation improves. The latter includes off-pump coronary grafting, smaller incisions, better intraoperative myocardial preservation, improving management of cardiopulmonary bypass, perioperative glucose control, and increasing use of arterial conduits as the radial artery comes of age and the gastroepiploic artery is reborn as a free graft. This brief review of the basics of coronary artery bypass is part experience with an effort to be fair-minded and balanced and to include that which is new and promising. It is imperative that we continue to innovate and distill the best from the old so that we can provide the optimal intervention for coronary artery disease.

Status of percutaneous coronary intervention and coronary artery bypass.

At present a rapid and profound change in myocardial revascularization has evolved from the work of Gruentzig. The recent technological advances have been so fast paced that there has not been ample time to fully assess each new facet of technology and pharmaceutics before another arrives. The interface between percutaneous intervention (PCI) and coronary artery bypass (CAB) is not well defined as previously so that continental, national and regional differences exist. The progress in PCI from balloon angioplasty to drug eluting stents has seen a progressive decline in restenosis and reintervention but relief of symptoms has not equaled that attained with CAB. Survival benefit for CAB over PCI has not been demonstrated in the many randomized clinical trials which are limited by selection of only 5-12% of potential patients so that higher risk patients and those with more extensive and complex coronary disease are excluded. These excluded patients are included in the registries where survival benefit for CAB over PCI is clearly evident. Situations less amenable to PCI include: left main disease; three vessel disease; vessels that are smaller, diffusely diseased or with distal lesions which are frequently associated with diabetes; ostial and bifurcation lesions; and coronary arteries that are tortuous, calcified or with very long lesions. It is in these situations that PCI does not provide revascularization equivalent to CAB. Surgeons must appreciate the success of PCI, acknowledge their reduced role in revascularization and strive to provide the best operation possible when the clinical situation demands it.