Myocardial metabolism assessed by microdialysis: a prospective randomized study in on- and off-pump coronary bypass surgery.

OBJECTIVE: The aim of the study was to compare energetic metabolism in the myocardium during coronary surgery with and without cardiopulmonary bypass by means of microdialysis. METHODS: Twenty-six low-risk patients were prospectively randomized to off-pump versus on-pump surgery. Microdialysis was used to sample myocardial interstitial fluid during and for 23 hours after surgery. RESULTS: Preoperative characteristics and clinical outcome were similar in both groups. Blood glucose and lactate did not differ between groups throughout the observation time. During surgery, intramyocardial levels of glucose, pyruvate and urea were unaffected in off-pump patients, while the same substances significantly decreased (p<0.05) in on-pump patients during cardioplegic arrest, and increased during reperfusion. Interstitial lactate levels were higher during off-pump surgery (p<0.05). From 3 to 15 hours after surgery, intramyocardial concentrations of glucose, urea and lactate were higher in off-pump patients (p<0.001), while pyruvate was higher in on-pump patients (p<0.01). Intramyocardial lactate/pyruvate ratio never differed between groups. Postoperatively, cumulative blood release of troponin-T was significantly higher in the on-pump group (p<0.005). CONCLUSIONS: Microdialysis could demonstrate significant differences in energetic metabolism between the two groups. Our data confirm and might help in explaining the lower release of myocardial ischemic markers after off-pump surgery.

Reconstruction of chronic aseptic sternal pseudoarthrosis after median sternotomy: initial experience with the Ley prosthesis.

It has previously been reported that the Ley prosthesis, a 0.5-mm-thick titanium alloy plate designed for reconstruction and stabilization of the unstable sternotomy, leads to shorter hospital stay and reduces the need for further surgical procedures in patients with postoperative mediastinitis after open heart surgery. We report our initial experience with the Ley prosthesis in patients with chronic aseptic sternotomy dehiscence. The study included 6 male patients (age 42-80 years) with opiate-derivate-dependent intractable pain and significantly reduced quality of life caused by noninfected sternal pseudoarthrosis and unstable sternotomy with large sternal bone tissue deficit. Four of the patients had undergone various surgical fixation procedures 8 days to 12 months after the primary operation. The patients were treated with reconstruction and stabilization of the sternum with the Ley prosthesis 10 to 40 months after the primary operation. In 1 patient bone transplantation was used. No immediate peri- or postoperative complications were observed, and all patients were discharged 4 to 11 days after surgery. One patient who received a bone transplant developed wound infection, and the prosthesis was removed 5 weeks after implantation. At 6-month follow-up all sternotomies were found stable, and patients reported that pain had decreased and quality of life was significantly improved. Our results demonstrate that the Ley prosthesis can be safely and efficiently used for the reconstruction and stabilization of the sternum in patients with intractable pain caused by noninfected postoperative sternal dehiscence and large sternal bone tissue deficit.

Angiographic results after the use of a sutureless aortic connector for proximal vein graft anastomoses.

The sutureless aortic connector system was recently developed to create anastomoses between the aorta and saphenous vein grafts for coronary artery bypass grafting. Ten consecutive patients scheduled for coronary artery bypass grafting were studied; in each patient one proximal anastomosis was performed using the aortic connector and another was sutured in the conventional manner to serve as the patient's own control. One graft in the sutured group had a significant stenosis and one of the grafts in which the aortic connector was used, was occluded. In this limited study the use of the sutureless connector system for proximal anastomosis shows satisfactory early graft patency (90%).

Endograft therapy for diseases of the descending thoracic aorta: results in 43 high-risk patients.

PURPOSE: To report an initial experience with endovascular stent-graft implantation for diseases of the descending thoracic aorta in high-risk patients. METHODS: Forty-three patients (28 men; mean age 67 years, range 17-82) with 16 descending thoracic aortic dissections, 14 aneurysms, 7 contained ruptures, 3 mycotic aneurysms, 2 posttraumatic pseudoaneurysms, and an aneurysm of an anomalous right subclavian artery were treated between June 1999 and July 2001. Twenty-three (53%) patients were treated emergently. RESULTS: There were no conversions to open repair, but 3 (7%) patients died during the first 30 days (pneumonia, multiorgan failure, and acute bowel ischemia). Thirteen (30%) patients suffered 18 major complications (8 strokes, paraplegia in 3, respiratory insufficiency in 6, and 1 renal failure). Of 7 (16%) endoleaks detected in the early postoperative period, 3 required additional stents, while the other 4 were treated conservatively. Follow-up, which averaged 19 +/- 6 months (median: 13; range 0-34), was 100% complete. Five (12%) patients died: 3 of aortic rupture at 34, 47, and 139 days, respectively, and 2 from heart failure at 3 and 15 months, respectively. No late migration or endoleaks have been detected in the remaining 35 patients; however, 1 (2%) patient showed progressive aortic dissection proximal to the stent-graft. In all other cases, the size of the aneurysm or the false lumen was unchanged or diminished. CONCLUSIONS: Treatment of descending thoracic aortic diseases with an endovascular approach has acceptable early mortality and morbidity in high-risk patients. In selected cases, stent-grafts may afford the best therapy.