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.

The implantable defibrillator: an electronic bridge to cardiac transplantation.

BACKGROUND: Sudden cardiac death (SCD) is common among patients awaiting heart transplantation. Medical management of SCD may fail due to lack of efficacy or adverse side effects. The implantable cardioverter-defibrillator (ICD) may extend patient survival until a donor heart is available. METHODS AND RESULTS: We reviewed 16 patients listed for transplantation between November 1988 and October 1991 who underwent ICD implantation for ventricular arrhythmias refractory to medical management. Mean age was 51.4 +/- 11.4 years (range, 19-66 years), mean ejection fraction was 15.4 +/- 3.0% (range, 10-21%), and underlying cardiomyopathy was ischemic (12 patients), valvular (one patient), or dilated (three patients). There was no mortality from ICD insertion. Fourteen patients were discharged before transplantation, and two patients remained in the hospital until transplantation. Twelve patients underwent transplantation after a mean of 155.7 +/- 113.7 days (range, 3-319) on the transplant list. The ICD delivered shocks for tachyarrhythmia associated with near syncope in 15 of 16 patients. ICD shocks numbered > 10 in five patients, 5-9 in three patients, and 1-4 in seven patients. There was no morbidity or mortality attributed to patch electrode removal. CONCLUSIONS: We conclude that the ICD can be implanted with minimal morbidity in transplant candidates, allowing the patients to be ambulatory and to leave the hospital while awaiting heart transplantation. In patients at risk of SCD, the ICD is an effective electronic bridge to transplantation.

Cardiac transplantation after prolonged graft preservation with the University of Wisconsin solution.

We tested the ability of University of Wisconsin solution to extend hypothermic preservation of the nonperfused heart during orthotopic baboon allotransplantation. Seven baboons received hearts after cardioplegia and storage (4 degrees C) with University of Wisconsin solution, with a preservation time of 14.2 +/- 1.6 hours. One animal died as a result of a technical error. Six survivors were immunosuppressed for 45 days and then put to death. Preservation did not alter heart weight or histologic features according to light and electron microscopy. Animals were weaned from bypass and returned to their cages without intravenous support within 3.9 +/- 0.8 hours. Weekly biopsies, electrocardiograms, enzyme analyses, echocardiograms, and right heart catheterizations demonstrated excellent cardiac function. University of Wisconsin solution can extend hypothermic cardiac preservation and has no deleterious effects on long-term myocardial function (up to 45 days). This study validates the rationale for human trials with preservation and storage in University of Wisconsin solution toward the goal of improving and prolonging donor heart preservation.

Laser activation of tissue sealant in hand-sewn canine esophageal closure.

UNLABELLED: Dehiscence rates of esophageal anastomoses are between 5% and 20%. Because small leaks between sutures might promote microabscess formation and lead to dehiscence, we postulated that a better initial physical seal might be beneficial. Reinforcement with laser activation of tissue sealant (LATS) is a new technique that has been shown to increase the bursting strength of anastomoses in other tissues. The tissue sealant is composed of 0.4 ml of hyaluronic acid and 0.2 ml of albumin, to which 3 drops of indocyanine green dye are added to give the sealant a peak absorbance of 805 nm, matching the wavelength (808 nm) of a small, hand-held diode laser. Since tissues do not absorb at this wavelength, laser energy is focused in the sealant, minimizing collateral thermal damage. To extend this concept, we assessed LATS in a canine model of esophageal closure. The esophagus was exposed via a right thoracotomy in 20 dogs, and two transverse incisions, 2 cm in length, were made in each esophagus (n = 40 closures). Both sites were closed with a single layer of interrupted 4-0 polyglycolic acid suture. Either the proximal or distal incision was randomly chosen to receive laser activation of tissue sealant. Tissue sealant was applied to the reapproximated edges of the hand-sewn closure, which was then exposed to diode laser energy. The end point was visible shrinking and desiccation of the sealant, which required about 2 minutes. Each esophagus was recovered at 0, 2, or 7 days postoperatively (n = 10, 5, and 5 dogs, respectively), bursting pressure was measured, and the closures were examined histologically. At all three time points LATS closures had significantly higher bursting pressures than control closures (time 0: 251 +/- 87 versus 105 +/- 46, p less than 0.0001; time 2 days: 296 +/- 36 versus 121 +/- 14, p less than 0.0013; time 7 days: 318 +/- 72 versus 197 +/- 60, p less than 0.0021). Histologic study revealed trace thermal injury, with regeneration of intact mucosal lining by 7 days. CONCLUSION: laser activation of tissue sealant is a simple technique that significantly increases the strength of esophageal closure and may reduce the prevalence of dehiscence.

University of Wisconsin solution versus crystalloid cardioplegia for human donor heart preservation. A randomized blinded prospective clinical trial.

We have previously shown the safety and efficacy of University of Wisconsin solution for hypothermic preservation of the human donor heart in a pilot group of 16 transplant recipients. The present study is a randomized clinical trial comparing University of Wisconsin solution to conventional preservation using crystalloid cardioplegia and saline storage within a 4-hour limit of ischemia. Heart transplant recipients (n = 42) were randomized into two groups: those receiving hearts preserved by University of Wisconsin solution, the UWS group (n = 22), and those receiving hearts preserved in the conventional manner, the CCS group (n = 20). Recipient age, gender, heart disease, and preoperative inotropic support and donor age, gender, and mean ischemic time in hours (UWS 2 hours 36 minutes, range 1 hour 36 minutes to 2 hours 53 minutes; CCS 2 hours 20 minutes, range 1 hour 20 minutes to 2 hours 44 minutes; p = not significant) were similar. Significant differences observed between the two groups included (1) mean time (minutes) from reperfusion to achieve a stable rhythm, (2) need for intraoperative defibrillations, (3) need for transient cardiac pacing, and (4) integrated postoperative creatinine kinase and aspartate aminotransferase release over 48 hours. There was no difference in postoperative electrocardiogram, endomyocardial biopsy, or hemodynamics. One UWS patient died of sepsis and another of a ruptured cerebral aneurysm. UWS is safe for donor organ arrest and preservation despite high viscosity and potassium concentration. When compared with CCS hearts, hearts preserved in UWS regained electrical activity more rapidly and had better myocardial protection as demonstrated by enzymatic analysis. Further investigation is required to determine the effects of UWS preservation on long-term survival, to determine the prevalence of rejection and graft atherosclerosis, and to test the ability of UWS to extend donor ischemic time in human cardiac 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.

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.

Improved heart preservation with University of Wisconsin solution: experimental and preliminary human experience.

We tested the ability of University of Wisconsin solution (UWS) to extend hypothermic nonperfused heart preservation in baboons and then proceeded to human transplantation. Orthotopic transplantation was performed in five baboons (UWS cardioplegia and storage [4 degrees C]; preservation time 10.3 +/- 0.6 hours). Four survivors were immunosuppressed for 45 days and killed. One animal died from disruption of the aortic anastomosis due to technical error. Preservation did not alter histology under light and electron microscopy or heart weight (at harvest, 51.4 +/- 11.6 g; before implant, 52.5 +/- 11.1 g). Animals were weaned from bypass (mean, 23 +/- 12 minutes) and returned to their cages without intravenous support within 3.6 +/- 0.6 hours. Weekly biopsy, electrocardiogram, enzyme analysis, echocardiogram, and right heart catheterization demonstrated excellent cardiac function. Following success in baboons, UWS was applied to human transplantation (n = 2, UWS cardioplegia and storage [4 degrees C]; preservation time 4.2 and 2.1 hours). The hearts returned to sinus rhythm within 4 minutes of reperfusion without defibrillation, and enzymatic and hemodynamic data reveal excellent heart preservation. Preliminary data suggest the ability of UWS to prolong heart preservation in baboons and be used safely in humans. Further studies are required to compare UWS with crystalloid cardioplegia and saline storage and to prolong donor heart preservation in humans.

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.

A preliminary study of dye-enhanced laser photosclerosis.

Laser ablation of veins after injection of wavelength-specific dyes to enhance and localize energy absorption could provide a useful adjunct to current treatment options. To enhance the absorption of diode laser energy at 808 nm, ear veins of 41 rabbits were infused with 2 to 3 ml of indocyanine green dye (maximum absorption, 805 nm) and exposed for 2 to 20 seconds. Animals were killed between 0 and 28 days after operation. Discrete time intervals of laser exposure exist during which various-sized vessels can be ablated without significant thermal injury to the overlying tissue. Small vessels (0.2 mm in diameter) blanch after 2 to 3 seconds of exposure, whereas medium-sized vessels (2 mm in diameter) require 8 to 10 seconds. Vessels can be ablated with a power density as low as 11.1 W/cm2. Specimens taken immediately after laser exposure show vessel wall thinning and a reirradiation effect, created as laser energy initially absorbed by dye is reemitted. By the seventh day after operation, a brisk inflammatory response and acanthosis of the overlying epidermal layer develop. The lumen is partially filled by thrombus with cellular invasion. By postoperative day 28, the epidermal thickening and inflammatory reaction have resolved; the vessel walls are fibrotic. The use of low-power, air-cooled diode lasers, in conjunction with wavelength-specific dyes, may provide a simple, viable, and cosmetically appealing alternative to the treatment of superficial varicosities of the extremities.

Binding of preformed xenoantibodies to porcine bioprosthetic valves.

We have investigated whether preformed antibodies against xenoantigens bind to cellular elements remaining on porcine bioprosthetic valves after various methods of preservation. Fresh porcine valves treated with either acetone, 4% formaldehyde, or 0.625% glutaraldehyde, as well as an unfixed valve, were incubated with antiserum against porcine xenoantigens. This serum was prepared using the affinity purification method with porcine lymphocytes as the target. The valves were stained with secondary fluorescein-conjugated antibody against immunoglobulin M or immunoglobulin G and examined under fluorescent microscopy. Intense binding of immunoglobulin M to the endocardium was observed in the unfixed valve as well as in valves fixed in acetone and formaldehyde. Glutaraldehyde fixation eliminated binding of antibody. Binding was not noted within the connective tissue. No binding of antiimmunoglobulin G was noted on the endocardium of any of the sections. Examination of three glutaraldehyde-treated porcine valves explanted from the aortic position after 10 years in situ showed no immunoglobulin deposition. These results demonstrate the elimination of antigenicity to preformed antibodies in the endocardium and connective tissue of glutaraldehyde-preserved porcine valves. The findings may, in part, explain the poor performance of formaldehyde-preserved bioprosthetic xenograft valves in the past and support the use of glutaraldehyde as a preferred agent for preservation of bioprosthetic endovascular materials.

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

Leakage 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 nm 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 less than 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.

Regulation of intracellular protein degradation in IMR-90 human diploid fibroblasts.

Human diploid fibroblasts (IMR-90) regulate their overall rates of proteolysis in response to the composition of the culture medium and the ambient temperature. The magnitude and, in some cases, the direction of the response depend on the half-lives of the cellular proteins that are radioactively labeled and the time chosen for measurements of protein degradation. Fetal calf serum, insulin, fibroblast growth factor, epidermal growth factor, and amino acids selectively regulate catabolism of long-lived proteins without affecting degradation of short-lived proteins. Fetal calf serum reduces degradative rates of long-lived proteins and is maximally effective at a concentration of 20%, but the effect of serum on proteolysis is evident only for the first 24 hr. Insulin inhibits degradation of long-lived proteins in the presence or absence of glucose and amino acids in the medium, but is maximally effective only at high concentrations (10(-5) M). Amino acid deprivation increases degradative rates of long-lived proteins for the first 6 hr, but then decreases their catabolism for the subsequent 20 hr. Lowered temperature is the only condition tested that significantly alters degradative rates of short-lived proteins. Although cells incubated at 27 degrees C have reduced rates of degradation for both short-lived and long-lived proteins compared to cells at 37 degrees C, lowered temperature reduces catabolism of long-lived proteins to a greater extent.