Coronary blood flow, metabolism, and function in dysfunctional viable myocardium before and early after surgical revascularisation.

OBJECTIVES: To assess the link between perfusion, metabolism, and function in viable myocardium before and early after surgical revascularisation. DESIGN: Myocardial blood flow (MBF, thermodilution technique), metabolism (lactate, glucose, and free fatty acid extraction and fluxes), and function (transoesophageal echocardiography) were assessed in patients with critical stenosis of the left anterior descending coronary artery (LAD) before and 30 minutes after surgical revascularisation. SETTING: Tertiary cardiac centre. PATIENTS: 23 patients (mean (SEM) age 57 (1.7) years with LAD stenosis: 17 had dysfunctional viable myocardium in the LAD territory, as shown by thallium-201 rest redistribution and dobutamine stress echocardiography (group 1), and six had normally contracting myocardium (group 2). RESULTS: LAD MBF was lower in group 1 than in group 2 (58 (7) v 113 (21) ml/min, p < 0.001) before revascularisation and improved postoperatively in group 1 (129 (133) ml/min, p < 0.001) but not in group 2 (105 (20) ml/min, p = 0.26). Group 1 also had functional improvement in the LAD territory at intraoperative echocardiography (mean regional wall motion score from 2.6 (0.85) to 1.5 (0.98), p < 0.01). Oxidative metabolism, with lactate and free fatty acid extraction, was found preoperatively and postoperatively in both groups; however, lactate and free fatty acid uptake increased after revascularisation only in group 1. CONCLUSIONS: MBF is reduced and oxidative metabolism is preserved at rest in dysfunctional but viable myocardium. Surgical revascularisation yields immediate perfusion and functional improvement, and increases the uptake of lactate and free fatty acids.

Adult cardiac surgery outcomes: role of the pump type.

OBJECTIVE: This study was carried out to evaluate whether the type of pump used for cardiopulmonary bypass (CPB; roller vs. centrifugal) can affect mortality or the neurological outcomes of adult cardiac surgery patients. METHODS: Between 1994 and June 1999, 4000 consecutive patients underwent coronary and/or valve surgery at our hospital; of these, 2213 (55.3%) underwent surgery with centrifugal pump use, while 1787 (44.7%) were operated on with a roller pump. The effect of the type of the pump and of 36 preoperative and intraoperative risk factors for perioperative death, permanent neurological deficit and coma were assessed using univariate and multivariate analyses. RESULTS: The overall in-hospital mortality rate was 2.2% (88/4000), permanent neurological deficit occurred in 2.0% (81/4000) of patients, and coma in 1.3% (52/4000). There was no difference in hospital mortality between patients operated with the use of centrifugal pumps and those operated with roller pumps (50/2213 (2.3%) vs. 38/1787 (2.1%); P=0.86). On the other hand, patients who underwent surgery with centrifugal pumps had lower permanent neurological deficit (34/2213, (1.5%) vs. 47/1787 (2.6%); P=0.020) and coma (20/2213 (0.9%) vs. 32/1787 (1.8%); P=0.020) rates than patients operated with roller pumps. Multivariate analysis showed CPB time, previous TIA and age as risk factors for permanent neurological deficit, while centrifugal pump use emerged as protective. Multivariate risk factors for coma were CPB time, previous vascular surgery and age, while centrifugal pump use was protective. CONCLUSIONS: Centrifugal pump use is associated with a reduced rate of major neurological complications in adult cardiac surgery, although this is not paralleled by a decrease in in-hospital mortality.

Non-invasive evaluation of right gastroepiploic artery with colour Doppler echography.

The right gastroepiploic artery has been increasingly used as a coronary bypass graft. Short- and mid-term patency rates support the supposition that the right gastroepiploic artery is a satisfactory bypass conduit. However, conclusive angiographic data on long-term patency rates are still lacking. An echo-colour Doppler method was used to detect patency of the right gastroepiploic artery grafts through an upper abdominal approach. A group of 24 patients with a right gastroepiploic artery graft to the right or posterior descending coronary artery, all of whom also had a postoperative angiographic study which showed 100% patency of the graft were used as a reference group. A second group of 89 patients was also investigated only with echo-colour Doppler during the postoperative period (mean 8.0 (range 1-48) months). A patent right gastroepiploic artery graft showed a biphasic velocity pattern. Systolic peak velocity ranged from 8 to 26 cm and diastolic peak velocity from 4 to 13 cm. The right gastroepiploic artery diameter ranged from 1.7 to 2.4 mm and flow from 10.2 to 58.8 ml. Among the second group were three patients who had, at their echo-colour Doppler examination, a possible occlusion of the right gastroepiploic artery graft; an angiographic study was conducted and the graft closure confirmed in all cases. Serial echo-colour Doppler evaluation of the right gastroepiploic artery blood flow pattern and diameter is a non-invasive and safe method to check the patency and flow capacity of the artery graft in follow-up studies.

Aprotinin and deep hypothermic circulatory arrest: there are no benefits even when appropriate amounts of heparin are given.

OBJECTIVE: To evaluate retrospectively the effect of 'high-dose' aprotinin on blood losses, donor blood requirements and morbid events on patients undergoing ascending aorta and/or aortic arch procedures with the employ of deep hypothermic circulatory arrest (HCA). METHODS: During the period 1987-1994, 39 patients underwent a thoracic aorta procedure with the employ of circulatory arrest; of these 18 (46.2%) were operated on during the period 1990-1994 and were given aprotinin intraoperatively following the 'high-dose' protocol (group I), while 21 (53.8%) who underwent surgery during the years 1987-1989, did not receive intraoperative aprotinin and served as historical controls (group II). Twenty-seven (69.2%) patients were male, 18 (46.2%) were operated on on an emergency basis, 15 (38.5%) were acute type A dissections, and two (5.1%) were redo-operations. Circulatory arrest times were not significantly different between the two groups (40 +/- 4 (S.E.) group I vs. 43 +/- 4 min group II, P = 0.62) likewise cardiopulmonary bypass (CPB) times (181 +/- 9 vs. 201 +/- 20 mm, P = 0.74) and the amount of heparin administered (32056 +/- 1435 vs. 31 691 +/- 1935 IU, P = 0.56). RESULTS: Postoperative blood loss was comparable between the two groups (1213 +/- 243 (median 850) group I vs. 1528 +/- 377 (median 880) ml group II, P = 0.87), as well as the number of units of donor blood transfused (9.4 +/- 3.0 (median 6) vs. 9.9 +/- 3.6, (median 5) P = 0.87), and revisions for bleeding (2/18, 11.1% vs. 3/21, 14.3%, P = 0.77). In-hospital mortality rate was not statistically different (5/18, 27.7% group I vs. 6/21, 28.6% group II, P = 0.92). There were no significant differences between the two groups in myocardial infarction (2/18, 11.1% vs. 0/21, 0%, P = 0.21), and postoperative renal failure rates (3/18, 16.7% vs. 2/21, 9.5%, P = 0.65). On the other hand, there was a trend towards an increased incidence of permanent neurological deficit (5/18, 27.7% group I vs. 1/21, 4.8% group II, P = 0.07) and towards a more complicated postoperative course (perioperative renal failure and/or myocardial infarction and/or neurological deficit either transient or permanent) (8/18, 44.4% group I vs. 4/21, 19% group II, P = 0.09) in group I patients. Forward stepwise logistic regression analysis, performed on the whole group of patients, identified chronic obstructive pulmonary disease (P = 0.010, Odds ratio (OR) = 5.7), aprotinin use (P = 0.017, OR = 5.1), and the number of units of blood collected intraoperatively by the cellsaver (P = 0.045, OR = 1.3/unit) as independent predictors of complicated postoperative course in the whole group of patients. CPB time (P = 0.040, OR = 1.032/min), circulatory arrest time (P = 0.053, OR = 1.22/min), and overall donor blood units transfused (P = 0.067, OR = 1.37/unit) emerged as independent risk factors for in-hospital mortality at multivariate analysis. CONCLUSIONS: Even when appropriate amounts of heparin are administered, 'high-dose' aprotinin probably is not an effective blood-sparing drug in deep HCA. Aprotinin should be employed cautiously in this clinical setting because of its possible correlation with an increased rate of postoperative morbid events.