Jan Otto Solem

Is the GraftConnector a valid alternative to running suture in end-to-side coronary arteries anastomoses?

BACKGROUND An animal study was carried out to compare long-term patency rates of coronary anastomoses performed with the GraftConnector versus running suture technique. METHODS 10 sheep, 45 to 55 kg, underwent off-pump coronary artery bypass grafting (right internal mammary artery to left anterior descending artery). In 5 animals, the anastomosis was performed with a GraftConnector and in 5 animals with 7-0 running suture. Intraoperative fluoroscopy and a fluoroscopic control at 6 months were performed. After 6 months, the animals were sacrificed and the anastomoses were examined histologically. RESULTS All animals survived at 6 months with 100% anastomosis patency rates in both groups. In the GraftConnector group, the anastomosis diameter at 6 months fluoroscopy was 118% of native left anterior descending artery versus 97% of the control group. Luminal anastomotic width at histology was 1.7 +/- 0.2 mm in the device group versus 1.6 +/- 0.1 mm in the control group. Mean intimal hyperplasia thickness was 0.21 +/- 0.1 mm in the device group versus 0.01 mm in the control group. CONCLUSIONS The GraftConnector provides a consistent and reproducible coronary artery anastomosis and reduces technical demand and manual dexterity in coronary operations. Long-term results demonstrate that off-pump coronary artery bypass grafting performed with the GraftConnector had the same patency rate and luminal width as those performed with running suture.

Hemoconcentration by ultrafiltration during open-heart surgery.

Ultrafiltration was used during extracorporeal circulation (ECC) with heart-lung machine in 17 critically ill cardiac patients. In ultrafiltration (hemofiltration), water and small molecules (e.g. urea, creatinine and electrolytes), are separated from the blood by hydrostatic pressure generated on the blood side of a semipermeable membrane. The patients had severe water overload for three reasons, viz. congestive heart failure (10), renal failure (6) or iatrogenic extreme hemodilution (1). On average 2090 (800-5700) ml water was filtered off, increasing the hematocrit from 25 to 33%. Three indications for ultrafiltration during ECC and two modes of such treatment are exemplified in three case reports. No negative effect of the treatment was observed. Ultrafiltration during ECC thus may help to improve the postoperative course in patients with severe water overload due to congestive heart failure, renal failure or iatrogenic extreme hemodilution.

Lung mechanics, gas exchange and central circulation during treatment of intra-abdominal hemorrhage with pneumatic anti-shock garment and intra-aortic balloon occlusion. An experimental study in pigs

Standardized intra-abdominal hemorrhage was induced in 7 anesthetized pigs. The resulting hypovolemic shock was treated with pneumatic anti-shock garment (PASG) followed by intra-aortic balloon occlusion. The effects of this treatment on circulation, lung mechanics and gas exchange were studied. Hemorrhage was induced by pulling out sutures introduced in the inferior caval vein. We found that the use of PASG partially restored mean arterial blood pressure from 44 +/- 6 to 66 +/- 6 mm Hg. When intraaortic balloon occlusion was added, the arterial pressure returned to basal levels. Cardiac output fell severely due to the hemorrhage from 3.7 +/- 0.2 to 1.3 +/- 0.2 liters/min and could not be restored during the treatment. A severe fall in total lung compliance was recorded after inflation of the PASG from 18.6 +/- 0.9 to 10 +/- 0.7 ml/cm H2O, this was accompanied by a fall in alveolar ventilation. These findings emphasize the severe restriction in lung function that occurred during treatment with PASG. Both parameters returned to near normal values when the PASG was deflated and the intra-aortic balloon was inflated. Pulmonary vascular resistance increased by more than 400% and remained high during the study period. There was no change in arterial PO2, however the fall in mixed venous PO2 caused by hemorrhage was reversed at the end of the treatment. Indirect monitoring of cerebral function by continuous EEG showed a decreased voltage during the hemorrhage, this was reversed by the combined treatment. We conclude that the outlined treatment makes it possible to restore central hemodynamics and preserve cerebral function at least for a short period of time until definite surgical treatment can be performed. However, severe restriction on lung mechanics, especially when PASG was inflated, makes it probable that ventilatory support can be necessary in such cases.

Mediastinal Drainage Blood: Potentialities for Autotransfusion after Cardiac Surgery

The rate of postoperative bleeding was studied in 32 patients with aortocoronary bypass surgery and in 18 with aortic valve replacement. In 12 of the 50 patients, more than 500 ml of shed mediastinal blood could be saved within 8 postoperative hours. Aerobic and anaerobic cultures of such blood were obtained from the suction reservoir in 20 cases 2, 4 and 6 hours postoperatively. The results were negative, apart from Staphylococcus albus in one 6-hour sample. The blood, which was in some degree hemolyzed, contained acceptable amounts of red cells and albumin. Alterations of the coagulation and fibrinolytic systems indicated massive proteolysis with degradation of the proteins to an extent that precluded coagulation. This proteolysis had taken place in the mediastinum, resulting in total defibrinogenation of the blood. The authors conclude that in about one-fourth of cases in cardiac surgery, postoperatively shed blood is worth saving for red cell and volume substitution.

Late cardiac tamponade following open-heart surgery: Diagnosis and Treatment

Late cardiac tamponade is a rare but serious complication following open-heart surgery. It occurred in 9 (0.8%) of 1 094 consecutive patients 6 to 13 (median 8) days after operation. Six patients had undergone valve replacement and three coronary bypass surgery. All were on anticoagulant medication postoperatively (median TT index 7%). Early symptoms of cardiac tamponade were nausea and general malaise (present in all 9 cases), whereas classical signs of tamponade such as arterial hypotension and distended neck veins appeared late. The cardiac silhouette was radiographically enlarged in all cases, but this finding was seldom diagnostic. Computed tomography gave the surest diagnosis and permitted quantitative assessment of the fluid in the pericardium. Pericardial needle puncture was effective in temporarily relieving the tamponade, but insertion of a tube by the subxiphoid approach gave definitive drainage.

Postoperative Autotransfusion of Concentrated Drainage Blood in Cardiac Surgery: Experience with a New Autotransfusion System

A new autotransfusion system was evaluated postoperatively in six patients undergoing aortocoronary bypass surgery. A hollow fiber hemofilter was integrated in the system, making it possible to concentrate the shed blood. The device functioned well, 825 ml diluted mediastinal drainage blood with a hematocrit of 23 was concentrated to a volume of 475 ml with a hematocrit of 36 and retransfused. Proteins were preserved, thus albumin concentration increased from 23 to 37 g/l in the autotransfusate. No negative side effects were registered after autotransfusion. A thorough coagulation study after retransfusion did not reveal any sign of activation of the coagulation cascade, nor were there any signs of an increased fibrinolysis.

The Linköping-Lund surgical experience with the HeartMate left ventricular assist system

Four transplant candidates fulfilling the Food and Drug Administration criteria for a permanent left ventricular assist device received a pneumatic HeartMate system as a bridge to heart transplantation. All patients survived and were fully rehabilitated at the time of transplantation, which was carried out 2 to 6 months after the initial operation. There were no major complications associated with the procedures. We are impressed by the effectiveness and safety of the device.

Lung transplantation at the University of Lund 1990-1995. Analysis of the first 39 consecutive patients

Between 1990 and 1995 39 patients were lung transplanted at the University Hospital in Lund. This is a retrospective review of survival and lung function in these patients. There were 17 single-lung transplants (SLT), 21 double-lung transplants (DLT) and 1 heart-lung transplant (HLT). Seven patients died during the period, giving an overall survival of 82%. One-year survival according to Kaplan-Meier survival analysis was 87%, and 2-year survival was 83%. Vital capacity and forced expiratory volume in 1 s (FEV1) 1 year after transplantation were 91% and 100% of predicted, respectively, in the DLT group and 60% and 50% in the SLT group. Bronchiolitis obliterans syndrome (BOS) developed in 11 of the 35 patients (31%) surviving more than 6 months, 2/21 in the DLT group and 8/13 in the SLT group and in the patient with HLT. The median time until detection of BOS was 11 months after the operation (range 6-18 months). Working capacity 1 year after transplantation was 60% of predicted in the DLT group and 47% of predicted in the SLT group. Ventilatory capacity was no longer function limiting. Lung transplantation today is a therapeutic option with a good medium-term survival and good functional results in selected patients with severe lung disease.

The GraftConnector experience. Long-term patency and histological work up in an animal model.

BACKGROUND A device to perform sutureless end-to-side coronary artery anastomosis has been developed by means of stent technology (GraftConnector). The present study assesses the long-term quality of the GraftConnector anastomosis in a sheep model. METHODS In 8 adult sheep, 40-55 kg in weight, through left anterior thoracotomy, the right internal mammary artery (RIMA) was prepared and connected to the left anterior descending artery (LAD) by means of GraftConnector, on beating heart, without using any stabilizer. Ticlopidine 250 mg/day for anticoagulation for 4 weeks and Aspirin 100 mg/day for 6 months were given. The animals were sacrificed after 6 months and histological examination of anastomoses was carried out after slicing with the connector in situ for morphological analysis. RESULTS All animals survived at 6 months. All anastomoses were patent and mean luminal width at histology was 1.8 +/- 0.2 mm; mean myotomia hyperplasia thickness was 0.21 +/- 0.1 mm. CONCLUSIONS Long-term results demonstrate that OPCABGs performed with GraftConnector had 100% patency rate. The mean anastomotic luminal width corresponds to mean LADs adult sheep diameter. We may speculate that myotomia hyperplasia occurred as a result of local device oversizing.