Joseph S. Auteri

Canine colonic anastomoses reinforced with dye-enhanced fibrinogen and a diode laser

SummaryLeakage from colonic anastomoses is a common cause of morbidity in patients recovering from bowel surgery. We evaluated a technique of laser-fibrinogen reinforcement to strengthen colonic anastomoses in a canine model. After creation of eight single-layer interrupted suture anastomoses in six dogs, indocyanine green-dye-enhanced fibrinogen was topically applied to the serosal surface and exposed to 808 mm diode laser energy. Immediately following colonic anastomosis, the mean leakage pressure was 137±22 mm Hg in the group (n=8) using sutures alone and 326±67 mm Hg (P<0.001) in the group (n=8) after the sutured anastomosis was reinforced with lasered-fibrinogen. On histological examination, no evidence of thermal injury to the tissue edges was noted and a layer of fibrinogen bridged the anastomotic gap. Laser dye-enhanced fibrinogen reinforcement significantly enhances the strength of sutured colonic anastomoses without causing appreciable thermal injury to the host tissues.

University of Wisconsin solution for human donor heart preservation: initial clinical experience.

Although in vitro and primate orthotopic transplant experiments have suggested the superiority of University of Wisconsin solution (UWS) compared with crystalloid cardioplegia and saline solution storage for hypothermic heart preservation, concerns about the viscosity and the high potassium concentration of UWS have precluded its use in human cardiac transplantation. To test the safety and efficacy of UWS, 16 patients received hearts arrested with, flushed with, and stored in UWS at 4 degrees C for a mean ischemic time of 153.3 +/- 30.7 minutes. After reperfusion, the hearts contracted vigorously and attained a stable sinus rhythm within 4.0 +/- 2.4 minutes, and the patients were weaned from bypass in 24.5 +/- 8.0 minutes. There was no evidence of acute or chronic ischemic myocardial injury by enzymatic analysis, electrocardiography, or biopsy specimen histology. The results suggest UWS can be safely used, within currently accepted limits of donor ischemic time, to arrest and preserve human hearts for transplantation. Further studies of preservation are required to compare UWS with crystalloid cardioplegia and saline solution storage and to test the ability of UWS to prolong the period of safe donor hypothermic ischemia in clinical heart transplantation.

Normal bronchial healing without bronchial wrapping in canine lung transplantation

The deleterious effect of steroids on bronchial healing in lung transplantation has led to the development of techniques to protect the anastomosis and to the exclusion of steroid-dependent patients from transplantation. The effect of steroids on bronchial healing was tested in a canine single-lung allotransplantation model. Twenty size-matched mongrel dogs (20 to 30 kg) underwent left lung transplantation without anastomotic wrap or direct revascularization. Postoperatively, all received daily doses of cyclosporine (15 mg/kg) and azathioprine (1 mg/kg) and were subdivided into three steroid dosage groups. Group A (n = 10) animals received 1.5 mg/kg of prednisone per day whereas groups B (n = 5) and C (n = 5) received 5.0 mg/kg of prednisone per day for 28 postoperative days. In addition, group C received prednisone (5.0 mg.kg-1.day-1) for 1 month preoperatively. In group A, 8 of 10 dogs survived 28 days without evidence of respiratory compromise, with anastomotic bursting pressure greater than 510 mm Hg. In group B, all 5 dogs survived to 28 days without evidence of respiratory compromise and with intact bronchial anastomoses (bursting pressures greater than 510 mm Hg). In group C, 3 of 5 animals survived to 28 days with intact anastomoses. Histological examination demonstrated normal bronchial healing in all anastomoses. These data suggest that preoperative steroid dependence should not be a contraindication to lung transplantation and that bronchial anastomotic wrapping with vascular tissue may not be essential.

Use of transesophageal echocardiography in the detection and consequences of an intracardiac bullet

A 17-year-old male sustained a gunshot injury to the chest. Transesophageal echocardiography showed the presence of a retained bullet in the pericardium and the absence of an intracardiac shunt, which provided important information for the treatment of the patient.

Effect of AICD patch electrodes on the diastolic pressure-volume curve in pigs☆☆☆

Although the automatic implantable cardioverter defibrillator (AICD) is effective against malignant ventricular arrhythmias, the effects of AICD patches on left ventricular diastolic properties have not been defined. Accordingly, extrapericardial (group E, n = 5) or intrapericardial (group I, n = 6) AICD patches were implanted through a median sternotomy in 11 anesthetized pigs. Six weeks later, using a left thoracotomy, the hearts were arrested with hypothermic cardioplegia. A balloon catheter was inserted into the left ventricle through the aortic root, and pressure-volume curves were measured before and after sequential removal of patches and pericardium. A dense intrapericardial fibrotic reaction in group I was not present in group E. Normalized left ventricular filling volumes in group E were significantly larger at pressures of 5.1 to 10, 15.1 to 20, and 20.1 to 28 mm Hg compared with group I (p less than 0.05). We conclude that intrapericardial AICD patches adversely affect left ventricular diastolic pressure-volume relations and recommend that AICD patches be placed in the extrapericardial location clinically whenever possible.

Reinforcement of high-risk anastomoses using laser-activated protein solders: a clinical study

Anastomotic leakage or breakdown can result in catastrophic complications and significantly increased post-operative morbidity and mortality. Certain anastomoses are subject to a higher incidence of disruption and are therefore termed high risk. In an attempt to decrease the risk of anastomotic leaks, we reinforced sutured anastomoses with a laser activated protein solder in patients undergoing esophagojejunostomies (n equals 2), lung transplantation (n equals 2), and pancreaticojejunostomies (Whipple procedure, n equals 5). The protein solder was composed of 1.0 ml of a 25% human albumin solution, 1.0 ml of sodium hyaluronate, and 0.1 ml of Cardiogreen dye. This composition was applied to the sutured anastomosis and activated with an 860 nm pulsed diode laser. Drains were placed when appropriate and patients were followed for up to 10 months post-operatively and assessed for clinical signs of anastomotic leaks. Results to data demonstrated that there were no immediate complications as a result of the procedure. Operative time was not significantly lengthened. There were no cases of clinically significant leakage from any of the reinforced anastomoses. Laser activated protein solders may help to reduce the incidence of leakage in high risk anastomoses. Large numbers of patients and longer follow-up is needed however, to draw significant conclusions.

Laparoscopic applications of laser-activated tissue glues

The rapid growth of laparoscopic cholecystectomy and other laparoscopic procedures has created the need for simple, secure techniques for laparoscopic closure without sutures. While laser tissue welding offers one solution to this problem, concerns about adequacy of weld strength and watertightness remain. Tissue solders are proteinaceous materials which are placed on coapted tissue edges of the tissue to be closed or sealed. Laser energy is then applied to fix the glue in place completing the closure. Closure of the choledochotomy following a laparoscopic common duct exploration is one potential application of this technique. Canine longitudinal choledochotomies 5 mm in length were sealed using several laser glues and using the 808 nm diode laser. Saline was then infused until rupture of the closure and peak bursting strength recorded. Fibrinogen glue provided moderately good adhesion but poor burst strength. Handling characteristics were variable. A viscosity adjusted fibrinogen preparation produced good adherence with mean weld strength 264 +/- 7 mm Hg. The clinical endpoint for welding was a whitening and drying of the tissue. New laser solders can provide a watertight choledochotomy closure of adequate immediate strength. This would allow reliable, technically feasible common bile duct exploration via a laparoscopic approach.

Tracheal anastomosis using indocyanine green dye enhanced fibrinogen with a near-infrared diode laser

A major obstacle to lung transplantation and combined heart- lung transplantation is dehiscence of the tracheobronchial anastomosis. We explored the possibility of laser welded anastomoses in canine tracheas in vivo. Laser anastomoses were performed on three-quarter circumferential anterior tracheotomies. A continous wave diode laser (808 +1 nm) at a power density of 9.6 watts/cm was used. Human fibrinogen was mixed with indocyanine green dye (ICG, max absorbance 805 nm) and applied to the anastomosis site prior to laser exposure. Animals were sacrificed at 0, 21 and 28 days post-operatively. At sacrifice weld bursting pressures were measured by raising intratracheal pressure using forced ventilation via an endotracheal tube. Sutured and laser welded anastomoses had similar bursting pressures, and exhibited satisfactory histologic evidence of healing. However, compared to polypropylene sutured controls, the laser welded anastomoses exhibited less peritracheal inflammatory reaction and showed visibly smoother luminal surfaces at 21 and 28 days post- operatively. Tracheal anastomosis using ICG dye enhanced fibrinogen combined with the near-infrared diode laser is a promising extension of the technology of laser tissue fusion and deserves further study.

Preliminary results of laser-assisted sealing of hand-sewn canine esophageal anastomoses

Dehiscence rates of esophageal anastomoses range between 5 and 20%. Causative factors include ischemia, tension, foreign body reaction, microabscesses, and the negative pressure within the thoracic cavity. Laser assisted tissue sealing (LATS) has been shown to decrease anastomotic leakage rates in other tissues. Using a canine model the efficacy of LATS in enhancing single layer hand swen intrathoracic esophageal anastomoses was assessed. Via a left thoracotomy, paired two centimeter transverse incisions (one laser sealed, one control) were made in the proximal and distal esophagus in nine dogs. Both were sewn using a single layer of 4-0 polyglycolic acid. A combination of albumin (0.2 cc), sodium hyaluronate (0.4 cc), and indocyanine green (1 gtt) was applied to one of the randomly chosen hand sewn repairs. The albumin/hyaluronate combination is used to provide a protein matrix across the anastomosis for ingrowth of fibroblasts. Indocyanine green dye selectively absorbs at

Preliminary results with sutured colonic anastomoses reinforced with dye-enhanced fibrinogen and a diode laser

OM805 nm which matches the output of the diode laser (808 +/- 1 nm), thus improving uptake of laser energy by the targeted tissues. The anastomosis was then exposed to continuous wave diode laser energy for