Does warm antegrade intermittent blood cardioplegia really protect the heart during coronary surgery?

OBJECTIVE: Intermittent antegrade blood cardioplegia (IABC) has been standardized as a routine technique for myocardial protection in coronary surgery. However, if the myocardium is known to tolerate short periods of ischemia during hypothermic arrest, it may be less tolerant of warm ischemia, so the optimal cardioplegic temperature of intermittent antegrade blood cardioplegia is still controversial. The aim of this study was to compare the effects of warm intermittent antegrade blood cardioplegia and cold intermittent antegrade blood cardioplegia on myocardial pH and different parameters of the myocardial metabolism. METHODS: Thirty patients undergoing first-time isolated coronary surgery were randomly allocated into two groups: group 1 (15 patients) received warm (37 degrees C) intermittent antegrade blood cardioplegia and group 2 (15 patients) received cold (4 degrees C) intermittent antegrade blood cardioplegia. The two randomization groups had similar demographic and angiographic characteristics. Total duration of cardiopulmonary bypass (108+/-17 and 98+/-21 min) and of aortic cross-clamping (70+/-13 and 65+/-15 min) were similar. The cardioplegic solutions were prepared by mixing blood with potassium and infused at a flow rate of 250 ml/min for a concentration of 20 mEq/l during 2 min after each anastomosis or after 15 min of ischemia. Intramyocardial pH was continuously measured during cardioplegic arrest by a miniature glass electrode and values were corrected by temperature. Myocardial metabolism was assessed before aortic clamping (pre-XCL), 1 min after removal of the clamp (XCL off) and 15 min after reperfusion (Rep) by collecting coronary sinus blood samples. All samples were analyzed for lactate, creatine kinase (MB fraction), myoglobin and troponin I. Creatine kinase and troponin I were also daily evaluated in peripheral blood during 6 days post-operatively. RESULTS: The clinical outcomes and the haemodynamic parameters between the two groups were identical. In group 1, XCL off and Rep were associated with higher coronary sinus release of lactate (5.5 +/- 1.8 and 2.2 +/- 0.5 mmol/l) than in group 2 (2.0 +/- 0.7 and 1.6 +/- 0.3 mmol/l, P < 0.05). Mean intramyocardial pH was lower in group 1 (7.23 +/- 0.08) than in group 2 (7.65 +/- 0.30, P < 0.05). There were no significant differences between the two groups with respect of creatine kinase (MB fraction) either after Rep or during the post-operative period. Lower coronary sinus release of myoglobin was detected at Rep in group 1 (170 +/- 53 microg/l) than in group 2 (240 +/- 95 microg/l, P < 0.05). At day 1, a lower release of troponin I was found in group 1 (0.11 +/- 0.07 g/ml) compared to group 2 (0.17 +/- 0.07 ng/ml, P < 0.05). CONCLUSION: With regards to similar clinical and haemodynamic results, myocardial protection induced by warm IAEX is associated with more acidic conditions (intramyocardial pH and lactate release) and less myocardial injury (myoglobin and troponin I release) than cold intermittent antegrade blood cardioplegia during coronary surgery.

[In coronary surgery can both internal mammary arteries be used systematically? Apropos of 560 patients]. / En chirurgie coronaire l'utilisation des deux artères mammaires internes peut-elle être systématique? A propos de 560 patients.

The grafts commonly used in coronary bypass surgery are the left internal mammary artery and the saphenous veins of the legs: the use of both internal mammary arteries, with potential long-term benefits, is only justified if the operative risk is not increased. Since 1987, the authors use both internal mammary arteries systematically in patients under 70 years of age and in good general condition. The retrospective analysis of 560 patients having undergone this surgery from 1987 to 1994 was undertaken to determine if this surgical option is justified without increased operative risk. The dissection of the mammary arteries is performed in a special manner by skeletonization technique. The total hospital complication rate was 12% with 9 deaths in the first 30 postoperative days (1.6%). Mediastinitis was observed in 6 patients (1.1%) Early angiographic controls showed a patent mammary graft rate of 98%. The use of both internal mammary arteries does not therefore increase postoperative morbidity or mortality. It may be proposed systematically in patients in good general condition and may provide long-term benefits in graft patency rates.

Bilateral skeletonized mammary artery grafting: experience with 560 consecutive patients.

OBJECTIVE: To test the hypothesis that the skeletonized technique of harvesting the internal thoracic artery improves the surgical results of bilateral internal thoracic artery grafting, we reviewed our 7-year experience with this technique. METHODS: Between July 1987 and December 1994, 560 patients received bilateral internal thoracic artery grafts and 236 additional grafts (average 2.6 +/- 0.6 anastomoses per patient). There were 515 men (92%) and the average age was 56.9 +/- 8.8 years. There were 63 diabetic patients (11.3%). During harvesting, the internal thoracic arteries were always totally skeletonized from the surrounding tissues without the use of electrocautery. RESULTS: Postoperative complications included reoperation for bleeding, 17 patients (3%), phrenic nerve paresis, 17 patients (3%), acute respiratory distress syndrome, 9 patients (1.6%), digestive complications, 8 patients (1.4%), neurologic complications, 6 patients (1.1%), and sternal complications, 6 patients (1.1%). No wound complications were observed in diabetic patients. The hospital mortality rate was 1.6% (9 patients, 2 cardiac causes). The early patency of internal thoracic artery grafts was 97.9%. Follow-up averages 29 +/- 20 months. There were 14 late deaths (4 cardiac causes). Angina recurred in 51 patients and the maximal stress test was abnormal in 47 patients. CONCLUSION: Bilateral internal thoracic artery grafting with skeletonized harvesting carried low post-operative mortality and morbidity and therefore it could be applied routinely without the fear of increased complication rate.

Effects of two different crystalloid cardioplegic solutions assessed by myocardial pH, tissue lactate content and energy metabolism.

OBJECTIVE: The influence of composition of crystalloid cardioplegia is imprecise in clinical practice. Therefore, we investigated changes in intramyocardial pH, tissue lactate content and energy metabolism during cardioplegic arrest with 2 different crystalloid cardioplegic solutions. METHODS: Twenty patients were randomly allocated to 2 groups: 10 patients had crystalloid cardioplegia buffered with bicarbonate (neutral pH of 7.8 at 20 degrees) with no additives (St Thomas' II solution) and 10 patients had a non buffered crystalloid cardioplegia (mildly acidic pH of 7.4 at 20 degrees) enriched with glutamate and mannitol (Menasché's solution). Tissue lactate and energy metabolism were measured on myocardial biopsy specimens and intramyocardial pH were continuously measured during cardioplegic arrest by a miniature glass electrode. RESULTS: There were no statistical differences in hemodynamic results and in AMP, ADP, ATP, lactate values measured on biopsy specimens. The curves of intramyocardial pH were very similar in the 2 groups, the median values were 7.42 +/- 0.1 in group 1 and 7.41 +/- 0.1 in group 2 (temperature corrected values) and the areas under the curves were 260 +/- 4 and 259 +/- 4 in groups 1 and 2 respectively (P = NS). CONCLUSIONS: Glutamate provided no additive metabolic myocardial protection, bicarbonate had a weak buffering capacity in cold cardioplegic solutions and the 2 studied crystalloid solutions warranted a good myocardial protection in clinical practice.

[Atypical coarctation of the thoracic aorta caused by fibromuscular dysplasia]. / Coarctation atypique de l'aorte thoracique par dysplasie fibromusculaire.

Fibromuscular dysplasia is a non-inflammatory disease unrelated to atherosclerosis of the small and medium sized arterial walls, which often affects the renal and carotid arteries and occurs mainly in women. The authors report a case of atypical coarctation of the thoracic aorta due to fibromuscular dysplasia confirmed histologically in a 27 year old man. Arteriography was performed because of hypertension and asymmetry of blood pressure measurements and showed irregular stenosis of the aortic isthmus and of the origin of the left subclavian artery. Surgery comprised resection of the pathological segment of the aorta which was replaced by a prosthetic tube with reimplantation of the left subclavian artery. Histological examination showed fibromuscular dysplasia in perimedial areas and diffusely throughout the media. To the author's knowledge this is the first case to be reported in the medical literature.

[Coronary artery bypass with 2 internal mammary arteries. Early clinical and angiographic results in 100 patients]. / Pontages coronaries avec les 2 artères mammaires internes. Résultats cliniques et angiographiques précoces chez 100 malades.

One hundred patients underwent coronary revascularisation with both internal mammary arteries between 1987 and 1990. The average age of the patients was 55 years. The left internal mammary was used in 97 of the 100 cases as a pediculated graft to revascularise the left anterior descending (66 cases), left lateral (27 cases) or a bissecting artery (4 cases). The right internal mammary was used as a pediculated graft in 51 cases and as a free graft to revascularise a left lateral (51 cases), left anterior descending (29 cases) or right coronary artery (20 cases). There was one death in the first 30 postoperative days. Morbidity was low with no cases of sternal infection. The average postoperative bleeding was 633 +/- 550 ml per patient. The incidence of phrenic nerve paralysis decreased from 36% in the first 50 patients to 6% in the second 50 patients. Angiography at the 10th postoperative day showed 4 occlusions out of 132 internal mammary arteries opacified (97% patency). Ninety four patients are asymptomatic and have negative exercise stress tests. Mortality and morbidity of coronary surgery using the two internal mammary arteries are therefore the same as those of conventional coronary surgery using saphenous veinar only one internal mammary artery, providing that it is reserved for patients in good general condition, under 65 years of age, without obesity or diabetes. This technique of coronary artery revascularization should provide better long-term results because of the high patency rate of the grafts.

[Value of coronary reperfusion in cases of very low cardiac output following coronary artery bypass grafts]. / Intérêt de la reperfusion coronaire dans les bas débits cardiaques graves après pontage coronaire.

From January 1986 to December 1988, 244 patients had a coronary artery revascularization at St Joseph Hospital. Four patients (1.8%) died in post operative time (less than 30 days). None died directly from cardiogenic shock. Five patients had a severe low cardiac output (2 h to 48 h post-op) and needed cardiac resuscitation. These patients were immediately taken to the operating room. The coronary bypasses were explored (2 technical errors corrected), the metabolic disorders were treated and a coronary reperfusion was done with the Buckberg's technique. All the patients could be weaned from cardiopulmonary bypass, two with intra aortic balloon pumping. One patient died of digestive complication the 10th postoperative day. The four other patients survived and are in good clinical condition. The severe low cardiac output after coronary revascularization can be reversible with resuscitation in operating room, short assistance, and coronary reperfusion.

[Improvement in the prognosis of severe mediastinitis by the use of muscle flaps]. / Amélioration du pronostic des médiastinites graves par les musculoplasties pédiculées.

Between 1984 and 1988, 12 mediastinitis were observed in a series of 1.724 cases of cardiac surgical procedures by sternotomy (0.7%). These 12 patients were retrospectively separated in 2 groups in terms of surgical management. In group I (5 patients in 1984 and 1985) the treatment was mediastinal irrigation and in case of failure, an omental transposition. In group II (7 patients in 1986, 86 and 88) the treatment was mediastinal irrigation and in case of failure, a mobilization of muscle flaps. Four patients died in group I of poly-visceral failure with a persistent severe sepsis. In group II, there was no death and the cicatrization was quickly obtained with an average length of stay in intensive care unit of 62 days. The mediastinal irrigation is the treatment of choice for benign mediastinitis, but the prognosis of severe mediastinitis was in our series greatly improved by muscle flap procedures realized with plastic and reconstructive surgical techniques.