[Brain death: myocardial consequences, an experimental study on pigs]. / La morte cerebrale: conseguenze miocardiche, studio sperimentale nel maiale.

It is well known that brain death is responsible for major problems encountered in the clinical setting that may alter heart graft viability before transplantation. To investigate these myocardial dysfunctions, a model of brain death was prepared in pigs. Anaesthetised pigs were ventilated with FiO2 of 50% through an endotracheal tube. Animals were monitored by measuring systemic arterial pressure, pulmonary artery pressure, cardiac output, left ventricular developed pressure and dP/dT (Millar probe), cardiac contractility (sonomicrometers crystals), ECG, myocardial tissue oedema (impedance spectroscopy) and heart rate. Blood samples were drawn to assess arterial blood gases, serum electrolytes, plasma catecholamine levels, LDH isoenzymes and ascorbil free radicals production. Myocardial high energy contents (adenosine triphosphate, creatine phosphate) were measured by spectroscopy MRI. After 30 minutes stabilisation, brain death was induced by ligation of the supra-aortic vessels. To assess myocardial impairment all the parameters mentioned were recorded at baseline, 1', 30', 60', 120' and 180' following the brain death. Results showed initial tachycardia and a significant increase (p < 0.05) in cardiac function at 1' and 30', related to the cathecolamine level variations, followed by a significant depression (p < 0.05) of cardiac contractility by the end of the third hour; there was no modification whatsoever of myocardial high energy contents and of ascorbil free radical and LDH isoenzymes productions. In this pig model of brain death the observed myocardial dysfunction was directly related to the induced catecholamine secretion without any myocardial high energy substrate depletion up until 180'. Such results could be taken into account when evaluating a donor heart, allowing to use organs judged nowadays not feasible, and could be of some help in lowering the number of the "défaillances" of the transplanted hearts.

Risk and results of bypass grafting using bilateral internal mammary and right gastroepiploic arteries.

From January 1990 to June 1994, 240 patients (mean age, 60 +/- 10 years) underwent myocardial revascularization with the exclusive use of in situ bilateral internal mammary and right gastroepiploic arteries. Left ventricular function was normal in 34% of patients, moderately impaired in 58.5%, and severely impaired in 7.5%. The mean number of distal anastomoses was 3.5 +/- 0.7 and the rate of complete myocardial revascularization was 80%. Early mortality was 0.4%, and complications occurred in 20 patients: myocardial infarction, 1.6%; intraaortic balloon pump, 0.8%; reoperation for bleeding, 0.8%; and mediastinitis, 0.4%. Early (15th postoperative day) angiographic control of grafts was performed in 51 patients; the rate of functional and patent anastomoses was 100% for internal mammary arteries and 96% for gastroepiploic arteries. Early functional results (3 +/- 1 postoperative months) were studied in 141 patients during exercise test with medical treatment: 99% were symptom-free and 14% had ischemic modification of electrocardiograms. A 2-year postoperative functional assessment without medical treatment was performed during exercise test in 66 patients: 98% were symptom-free and 26% had ischemic modification of electrocardiograms; during the same procedure, thallium myocardial scintigraphy was obtained in 50 patients and 18 patients had moderate ischemic defect on exercise. Ischemic modifications of electrocardiograms and defects seen on thallium scintigraphy were correlated significantly with incomplete revascularization (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Antegrade/retrograde cardioplegia in arterial bypass grafting: metabolic randomized clinical trial.

The metabolic effects of combined antegrade/retrograde and antegrade cardioplegia on myocardial protection were evaluated and compared in 30 patients who underwent myocardial revascularization. All patients had three-vessel coronary artery disease, and the revascularization was done with exclusive use of arterial grafts (internal mammary artery, gastroepiploic artery). Myocardial protection consisted of oxygenated crystalloid cardioplegia, topical slushed ice, and moderate systemic hypothermia (34 degrees C). The patients were randomly separated into two groups: group A (n = 15), who received antegrade cardioplegia, and group A/R (n = 15), who received combined antegrade/retrograde cardioplegia. There was no significant difference between the two groups concerning preoperative and intraoperative data. After the first dose of cardioplegia, right ventricular temperature was significantly lower in group A/R (15 +/- 2 degrees versus 19 +/- 5 degrees C; p < 0.05), and there was no significant difference between the two groups in left ventricular temperature. Coronary sinus blood samples were obtained before bypass and 5, 10, and 15 minutes after reperfusion; there was no difference between the two groups concerning lactates, superoxide dismutase, and glutathione peroxidase. After reperfusion, malondialdehyde levels increased significantly in group A and there was no change in group A/R, with a significant difference between the two groups (at 10 minutes after reperfusion, 0.80 +/- 0.20 versus 0.53 +/- 0.16 mumol/L; p < 0.05). Right and left ventricular myocardial biopsies were performed before bypass and 15 minutes after reperfusion; there was no significant difference between the two groups concerning adenosine triphosphate and creatine phosphate myocardial concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Technical aspects and late functional results of gastroepiploic bypass grafting (400 cases).

From January 1990 to February 1994, 400 patients (mean age 59 +/- 9 years) underwent myocardial revascularization using the right gastroepiploic artery (GEA) to bypass the right coronary artery trunk or branches. They represented 40% of all patients undergoing isolated coronary surgery during the same period, from 19% in 1990 to 54% in 1994. Left ventricular function was normal in 32% of patients, moderately impaired in 62% and severely impaired in 6%. The GEA was used alone in six patients, associated with one internal mammary artery (IMA) in 111 patients (two arterial grafts, 2.2 +/- 0.4 anastomoses) and with both IMAs in 283 patients (three arterial grafts, 3.4 +/- 0.6 anastomoses); no vein graft was used. The rate of complete myocardial revascularization was 79%. Early mortality was 1.7% and influenced by left ventricular ejection fraction (P < 0.05). Complications occurred in 37 patients: myocardial infarction 4%, intra-aortic balloon pump 0.5%, reoperation for bleeding 0.5%, mediastinitis 0.25%. Early (15th postoperative day) angiographic control of the GEA graft was performed in 104 patients operated from January 1990 to December 1991 and the patency rate was 92%; anomalies of GEA were three occlusions, five stenoses, three competitive flow, no string or slender sign. Early functional results (3 +/- 1 months postoperatively) were studied in 192 patients during exercise test with medical treatment: 99% were symptom-free and 14% had electrocardiographic (ECG) ischemic modification significantly correlated with incomplete revascularization (P < 0.01). The 2- and 4-year actuarial survival rate was 96.7 +/- 1.9%. The rate of late cardiac events was 2% patient/year; Angioplasty for GEA graft failure was required in four patients. A 2-year postoperative functional assessment without medical treatment was performed during exercise test in 66 patients who had received three arterial grafts: 98% were symptom-free and 26% had ECG ischemic modification significantly correlated with incomplete revascularization (P < 0.01); during the same procedure, thallium myocardial scintigraphy was obtained in 50 patients: 18 patients (36%) had asymptomatic ischemic defects on exercise significantly correlated with incomplete revascularization and ECG ischemic changes (P < 0.01). However, posterior thallium defects demonstrated limited GEA flow at the maximum level of exercise in at least 8% of patients. Myocardial revascularization using the GEA can be achieved with minimal operative risk and offers satisfactory functional results and midterm survival rate.

Thromboembolic risk and late survival after mitral valve replacement with the St. Jude Medical valve.

From January 1979 to December 1990, 397 consecutive patients (mean age, 55 +/- 11 years) underwent mitral valve replacement with the St. Jude Medical valve. Associated procedures performed were 174 multiple valve replacements, 24 coronary artery bypass graftings, 25 tricuspid repairs, and 13 left ventricular myectomies. The continuous intravenous administration of heparin was started on the first postoperative day and maintained until effective oral anticoagulation, started on the seventh day, was achieved (INR, 3 to 4.5). Follow-up consisted of 2,402 patient-years (pt-y) (mean, 6.1 +/- 0.2 years) and was 97% complete. The early (30-day) mortality was 3.5%; the 5-year and 10-year actuarial survivals were 86% +/- 4% and 73% +/- 6%, respectively. Survival was less in patients who had been in an advanced preoperative functional class (p = 0.02) and in those who underwent multiple valve replacements (p = 0.05). The 5-year and 10-year survivals in patients who underwent isolated mitral valve replacement and who were in preoperative New York Heart Association functional class II and III, were 90% +/- 5% and 82% +/- 7%, respectively. The early and late mortality and the incidence of deaths resulting from heart failure and sudden deaths were higher in patients who had undergone multiple valve replacements (p = 0.05). In terms of all deaths, 47% (36/77) were valve related (including 12 sudden deaths, 0.50%/pt-y). Thromboembolic complications occurred in 44 patients, and these were broken down as follows: embolism, 1.46%/pt-y, and valve thrombosis, 0.37%/pt-y.(ABSTRACT TRUNCATED AT 250 WORDS)

[Surgical plasty of the coronary trunks: an alternative to bypass techniques]. / Plastie chirurgicale des troncs coronaires: une alternative aux techniques de pontages.

Between January 1991 and December 1993, surgical coronary angioplasty was performed in 12 patients with an average age of 59 years: right coronary artery (17), left main coronary artery (3) and bilateral angioplasty (2). Internal mammary or gastroepiploic artery bypass grafts were associated on another vessel in 5 patients and 1 patient also underwent aortic valve replacement. There was no early mortality (1 month), or perioperative myocardial infarction. At the 15th postoperative day, the angiographic result was satisfactory in all patients. At 6 months, exercise testing was negative in all cases (maximum load 140 +/- 20 watts). Reoperation for bypass surgery was necessary in 1 patient because of symptomatic occlusion of the left anterior descending left anterior descending artery, one year after angioplasty of the left main coronary extending to the proximal left anterior descending. With a mean postoperative follow-up of 19 +/- 7 months (6 to 31 months), all patients are asymptomatic: 5 of the 6 angioplasties controlled angiographically at 1 year were patent without any signs of progression (1 occlusion/reoperation). Surgical angioplasty of the main coronary vessels is a sure and reliable procedure: it restores physiological coronary perfusion, economises venous and arterial vessels and is no obstacle to percutaneous transluminal coronary angioplasty.

Surgical angioplasty of the coronary trunks: an alternative to bypass techniques.

AIM: To test the value of surgical angioplasty of the coronary trunks as an alternative to bypass techniques. PATIENTS AND METHODS: Surgical angioplasty of the coronary trunks was performed in 12 patients (mean age 59 +/- 9 years), of whom nine underwent right coronary trunk angioplasty, five underwent left main coronary artery angioplasty, and two patients underwent bilateral coronary trunk angioplasty. A transpulmonary approach to the left main coronary artery was used. The patch consisted of saphenous vein in the first two patients but in the rest pericardium was preferred. Associated bypass procedures to the other coronary network using internal mammary or gastroepiploic arteries were performed in six patients, and one patient had a concomitant aortic valve replacement. RESULTS: No early mortality (30-day) or morbidity was observed and all procedures were successful. A 15-day angiographic study revealed an excellent result in all 14 angioplasties. After 6 months, all patients were free of symptoms during exercise stress testing (maximum level of exercise 140 +/- 20 W). One patient with a recurrence of angina underwent a second operation after 1 year because of left anterior descending coronary artery occlusion after bilateral angioplasty. Another angiographic study was obtained after 1 year in three other patients, which showed excellent results (four angioplasties controlled). After a mean follow-up period of 17 +/- 7 months (range 6-31), all patients were symptom-free, and with the exception of the one reoperation, no cardiac events were reported. CONCLUSIONS: Provided that contraindications (calcifications, involvement of the distal bifurcation) are respected, surgical angioplasty of the coronary trunks is safe, restores physiologic coronary perfusion, is economical with bypass material, and provides good results.