Notes: Increasing numbers of patients with extensive coronary artery disease present for surgical revascularization. Diffuse atherosclerosis of the anterior descending artery remains a significant challenge and endarterectomy may be required to increase graft outflow. A surgeon may choose local endarterectomy or be accidentally forced into endarterectomy when attempting to split a lesion distal to a critical stenosis. Distal traction endarterectomy may be performed through a medium sized arteriotomy and closed with a vein patch, to which an internal mammary artery (IMA) or saphenous vein graft is constructed. More diffuse disease, or the breaking of an endarterectomy specimen, may require a direct vision total endarterectomy of the entire length of the left anterior descending coronary artery (LAD), which is then closed by a long vein patch. The IMA is not usually grafted to such an extensive reconstruction. There has not been an increase in perioperative risk from LAD endarterectomy when compared to patients undergoing coronary artery bypass grafting without endarterectomy. (J Card Surg 1994;9:89–96)

Notes: Abstract From November 1989 to December 1994, we performed 2264 bypass procedures. Data were collected prospectively. The population was divided into three subgroups: group 1 = single internal mammary artery (IMA) ± veins (n = 1584); group 2 = veins only (n = 503); and group 3 = two or more arterial conduits ± veins (n = 177). Patients who received only saphenous vein conduits (group 2) were significantly older (66.7 ± 8.9 years) than either group 1 (60.3 ± 8.3 years) or group 3 (51.6 ± 9.2 years). Furthermore, this cohort group had the highest percentage of females (28.6%), urgent cases (43.5%), preoperative myocardial infarction (MI) (18.5%), and redo surgery (5.4%). In contrast, patients who received two or more arterial conduits were 94.9% male, and had the lowest incidence of urgent cases (18.1%) and redo surgery (0.5%). Mortality was 1.4% in group 1 and 3.2% in group 2; there were no deaths in group 3. Furthermore, group 2 patients had the highest incidence of perioperative MI (6.6%), low output syndrome (22.1%), intra-aortic balloon pump (IABP) assist (6.2%), and stroke (2.7%). By multivariate logistic regression analysis (odds ratio in parentheses), redo surgery (7.92), preoperative IABP (5.53), poor LV function (4.01), renal impairment (3.94), and advanced age (2.12) were all predictors of operative mortality. When mortality and morbidity (death, infarction, low output syndrome, IABP assist) were combined, regression analysis revealed that in addition to the above variables, female gender and cold cardioplegia were also independent predictors of combined mortality and morbidity. Resource utilization was determined for the three patient groups. There was concern that the increased technical demands of multiple arterial grafting along with longer periods of aortic occlusion and pump times may lead to increased complications and prolonged hospital stay. However, we found that group 3 had the lowest ventilation time, intensive care unit stay, and hospital stay. The results no doubt were influenced by case selection. Whether or not this approach to revascularization will increase long-term survival and freedom from reoperation will require further study.

Notes: Abstract  A prospective randomized trial was conducted to evaluate the early efficacy and safety of the Gortex surgical membrane. Three hundred two patients (265 males, 37 females) undergoing isolated coronary bypass surgery were randomized to receive a Gortex membrane (GM = 138) or have the pericardium left open (complication [C] = 164). The groups did not differ in age, gender, urgency of procedure, length of procedure, or use of arterial grafts. Two deaths occurred in each group giving an overall mortality of 1.3%. Fifty-three (17%) patients experienced some complication (C = 34, 21%), GM = 19 (14%). Although the combined complication rate was higher in the control group, this was not statistically significant (X2 = 2.51, p = 0.11). Postoperative is-chemic events (C = 8, GM = 4) observed between the groups were not significant (X2 = 0.05, p = 0.8), and no statistically significant difference was observed between the incidences of infections (C = 7, GM = 5) or mediastinal complications (C = 3, GM = 3). The Gortex surgical membrane can be used safely without increasing the risk of infection or mediastinal complications. The incidence of recurrent myocardial ischemia, a possible indicator of graft compression, was not higher following membrane implantation. Efficacy at injury prevention will need to be determined by a longitudinal follow-up study presently underway.

Notes: We report our initial experience from April 1992 to November 1993 with a stentless porcine valve (Toronto SPVTM Valve, St. Jude Medical) for aortic valve replacement (AVR) in 21 consecutive patients and compare this group to a matched cohort that underwent AVR with a Hancock II (Medtronic) bloprosthesis. There were no hospital deaths in either group. Postoperative hospitalization was 5.5 ± 0.8 versus 7.0 ± 2.3 days (p = 0.004). Aortic cross-clamp time was 114.5 ± 15.7 min In the SPV group and 96.0 ± 25.0 min in the Hancock II group (p = 0.003). Complications in the SPV group were: one patient suffered perioperative infarction, one patient required late reoperation for left main stenosis, and one patient died suddenly following femoral thrombectomy at another center. Complications in the Hancock II group included: one patient with postoperative low output syndrome, and two late deaths (one from an aortic dissection and the other from chronic liver disease secondary to alcohol abuse). Comparison data indicate that the average size valve implanted in the SPV group was higher than in the Hancock II group (26.3 ± 1.9 vs 24.0 ± 1.9, p = 0.001). In the SPV group, 16 patients had 0 or trivial regurgitation and 1+ regurgitation was seen in 5 patients; regurgitation did not change over a 12-month follow-up. We observed a decrease in gradients over time (p 〈 0.01). Our results are compatible with a hypothesis that the ventricle undergoes remodeling over time, once the obstruction is relieved. We think the stentiess design is an important feature that allows this to occur. Furthermore, this design allows for the implantation of a larger size valve for the same body size, as well as for decreased shear forces during diastole, with accompanying better hemodynamics, and potential improvement in longevity. These results indicate that the SPV valve has excellent hemodynamic characteristics that do not appear to change over a short follow-up period.

Notes: Patients with postinfarction angina undergoing surgery for unstable angina face an increased risk of operative mortality. Between January 1982 and December 1987, clinical, angiographic, and operative data was collected prospectively in 588 unstable patients with a prior myocardial infarction within 30 days of surgery (MI) and 5951 unstable patients without preoperative damage (NONMI). MI patients were characterized as being older (age ± 70 years: MI, 19.7%; NONMI, 11.6%; p 〉 0.001) and having more left ventricular dysfunction (left ventricular ejection fraction 〉 40%: MI, 34.8%; NONMI, 26.4%; p 〉 0.001). Semi-elective surgery was performed in 82.0% of NONMI patients while 76.9% of MI patients underwent urgent surgery. Operative mortality was increased in MI patients (MI, 11.1%; NONMI, 4.0%; p 〉 0.001) which was related to the extent of preoperative MI (non-Q wave, 8.3%; Q wave, 17.5%; p 〉 0.001). Stepwise logistic regression analysis identified preoperative MI as an independent risk variable of operative mortality for unstable angina. Separate multivariate analyses were performed to identify the independent predictors for MI and NONMI patients. The multivariate predictors of operative death for MI patients were left ventricular dysfunction, reoperative coronary surgery, nonuse of the internal mammary, age, transmural MI (relative risk 2.11 vs non-Q wave infarction) and left main stenosis. For NONMI patients, the independent variables were urgent operation, left ventricular dysfunction, reoperation, female gender, left main stenosis, and age. The results of this study indicate that recent preoperative MI adversely influences the surgical results in patients with unstable angina. Alternative treatment strategies are warranted for high risk patients, particularly those with transmural MIs and impaired ventricular function.

Notes: All available controlled studies of warm versus cold and antegrade versus retrograde delivery of cardioplegia were reviewed to assess the incidence of perioperative stroke and adverse neuropsychological outcomes. Nine randomized trials and substudies and two studies with immediate historical consecutive controls reported neurological outcomes and were described as warm versus cold. Pooled event rates for perioperative stroke were 1.5% for warm antegrade, 3.14% for warm retrograde, 1.7% for cold antegrade, and 0% to 1.2% for cold retrograde. Examining within trial differences, only one study showed a significant disadvantage to warm 4.5% versus cold 1.4% on incidence of perioperative stroke, but the design does not permit determination of whether the difference is due to systemic temperature, retrograde coronary perfusion, or other factors. Furthermore, if only warm (〉 33°C) versus cold (〈 30°C) systemic perfusion is examined in all studies for the incidence of stroke irrespective of cardioplegia temperature or antegrade versus retrograde coronary perfusion (warm 2.1%; cold 1.6%), the above study remains a significant outlier. This suggests that the differences found are unlikely to be due to temperature but may be related to antegrade versus retrograde coronary perfusion. Review of randomized trials evaluating neuropsychological function post-cardiopulmonary bypass (post-CPB) also failed to reveal any advantage related to temperature of systemic perfusion. Since manipulations that are most likely to give rise to cerebral embolization are uniformly carried out at normothermia at the beginning and end of the operation, it is not entirely unexpected that the incidence of neurological events was found to be independent of the temperature of CPB. Because stroke is both too rare and too variable in magnitude by chance alone, no studies to date have adequately assessed stroke severity in relation to systemic perfusion temperature or mode and route of cardioplegia delivery.

Notes: There is renewed interest in the use of the radial artery as a conduit for coronary artery bypass. Fifty patients underwent bypass surgery using the radial artery in addition to other conduits between November 24, 1992 and November 8, 1994 at our institution. The mean age was 54.4 ± 9.1 years (mean ± SD) and 47 of the patients were male. There were 3.6 ± 0.9 anastomoses per patient, of which 2.2 ± 0.4 were arterial anastomoses. The most common target vessel for the radial artery has been the obtuse marginal (58.8%), with the aorta as the usual site for proximal anastomosis (80.4%). There have been no ischemic hand complications and no radial nerve deficits. There have been no early or late deaths and no myocardial ischemic complications related to the use of the radial artery. We present the techniques used at our institution for the use of the radial artery as a conduit for coronary artery bypass.

Notes: Improvements in surgical technique and advances in myocardial protection have resulted in low rates of morbidity and mortality despite a greater incidence of high-risk patients. Noncardiac morbidity prolongs hospital stays and increases the costs of cardiac surgery. This study examines the preoperative predictors of stroke following isolated coronary bypass surgery. The clinical records of 3910 consecutive patients who underwent isolated coronary bypass surgery at the University of Toronto were reviewed. Stepwise logistic regression identified six independent predictors of stroke following CABG (percent in parentheses) and calculated factor adjusted odds ratios (OR) for each risk factor. Triple vessel coronary artery disease was the most important predictor (1.9%, OR 5.71), followed by normothermic systemic perfusion (3.8%, OR 4.85), age 〉 70 years (3.2%, OR 3.88), a previous history of transient ischemic attacks or stroke prior to surgery (6.1 %, OR 3.7), peripheral vascular disease (4.7%, OR 2.77), and diabetes mellitus (2.6%, OR 2.01). The mechanism of stroke is likely different between these high-risk groups and strategies to prevent postoperative stroke should focus on the mechanisms responsible in high-risk patients.

Notes: Abstract The Toronto Stentless Porcine Valve has been extensively used for aortic valve replacement. A standardized, detailed description of a preferred operative technique has been absent from the literature. A method is described that stresses (a) proper position and orientation of the aortotomy, (b) debridement of the diseased native valve, (C) proper sizing of the aortic root and choice of prosthesis and (d) implantation of the valve. Using this technique, the prosthesis can be reproducibly implanted with relative ease, without valvular insufficiency or coronary obstruction.

Notes: Coronary endarterectomy (TEA) is performed infrequently during coronary artery bypass graft (CABG) surgery due to the impression that it results in higher rates of myocardial infarction (MI), operative mortality (OM), and poor long-term outcome. To assess the effectiveness of TEA, 1, 228 patients undergoing isolated CABG between 1982 and 1989 were evaluated. The incidence of OM (3.2%) and MI (6.0%) following TEA was similar to conventional CABG (OM = 3.8%, MI = 5.5%, p = NS). The incidence of low output syndrome (LOS, 15.1%) and intraaortic balloon pump insertion (IABP, 4.5%) following TEA was similar to conventional CABG (LOS = 12.6%, IABP = 6.0%, p = NS). The highest level of the cardiac specific isoenzyme (CK-MB) released following surgery was similar for the TEA group (46 ± 49) and conventional CABG group (42 ± 44, p = NS). Ventricular dysfunction, urgent surgery, left main stenosis, advanced age, and reoperative surgery were similar in the TEA and conventional CABG groups. At a mean follow-up of 4.2 years, 65.6% of all TEA patients were free of angina, 44.4% were gainfully employed, and 62% were in New York Heart Association Class I. The incidence of late myocardial infarction was 5.4%. The 5-year actuarial survival was 90%. Patients with double TEA and limited TEA (〈 3 cm TEA specimens) tended to have a lower 5-year survival. With strict criteria for selection of TEA patients and with significant technical experience, the short- and long-term results of TEA are comparable to conventional CABG.