Polystyrene microspheres enable 10-color compensation for immunophenotyping of primary human leukocytes.

Compensation is a critical process for the unbiased analysis of flow cytometry data. Numerous compensation strategies exist, including the use of bead-based products. The purpose of this study was to determine whether beads, specifically polystyrene microspheres (PSMS) compare to the use of primary leukocytes for single color based compensation when conducting polychromatic flow cytometry. To do so, we stained individual tubes of both PSMS and leukocytes with panel specific antibodies conjugated to fluorochromes corresponding to fluorescent channels FL1-FL10. We compared the matrix generated by PSMS to that generated using peripheral blood mononuclear cells (PBMC). Ideal for compensation is a sample with both a discrete negative population and a bright positive population. We demonstrate that PSMS display autofluorescence properties similar to PBMC. When comparing PSMS to PBMC for compensation PSMS yielded more evenly distributed and discrete negative and positive populations to use for compensation. We analyzed three donors' PBMC stained with our 10-color T cell subpopulation panel using compensation generated by PSMS vs.PBMC and detected no significant differences in the population distribution. Panel specific antibodies bound to PSMS represent an invaluable valid tool to generate suitable compensation matrices especially when sample material is limited and/or the sample requires analysis of dynamically modulated or rare events.

Development and characterization of an infection inhibiting urinary catheter.

Catheter associated bacturia is common in hospitals and nursing homes. The objective of this study was to develop an infection inhibiting urinary catheter for prolonged use. Methods were established to add chlorhexidine digluconate (CHG) to a silicone elastomer and to compression mold the material to form a urinary catheter. CHG was randomly dispersed in the elastomer to be released through elution. Samples of the material, with CHG concentrations ranging from 1 to 4% by weight, were tested for in vitro release characteristics over a 28 day period and for in vivo toxicity over a 7 day period. Release profiles followed a common pattern for each concentration: an initial peak during the first 24 hours was followed by a subsequent decline. CHG amounts released into the saline medium were directly related to the CHG concentration of the samples; 4% samples released the largest amounts and 1% samples released the least amounts. Both 3% and 4% CHG by weight samples released measurable amounts of CHG throughout the entire observation period, whereas 1% CHG by weight samples were depleted after 9 days, and 2% CHG by weight samples were depleted after 19 days. No samples were found to be toxic during in vivo evaluations. These studies suggest that CHG bearing silicone rubber urinary catheters could resist surface colonization and infection for extended periods without toxicity.

Left ventricular aneurysm: Twenty-year surgical experience with 1572 patients at the Texas Heart Institute.

From January 1958 through December 1979, 1572 patients underwent surgery for left ventricular aneurysm (LVA) in our institution. The series included 1365 men and 207 women, with a ratio of 6.5:1. Ages ranged from 25 to 79 years, with a mean of 54.7 years. Most patients were in NYHA functional Class III or IV, and all had sustained at least one documented myocardial infarction. During the first decade, LVA resection alone was performed, but after the advent of aortocoronary bypass (ACB) surgery, the majority of patients underwent ACB along with LVA resection. Some required additional septoplasty, mitral valve replacement, annuloplasty, or aortic valve replacement. In all groups, the mortality was higher for women than for men. Early deaths were due primarily to acute or progressive myocardial failure secondary to recurrent myocardial infarction. Follow-up information for 6 months to 8 years was obtained by means of questionnaires submitted to patients and referring physicians. Of 475 patients who underwent LVA resection and ACB and who responded, 92.2% were either improved or asymptomatic.

A method of intraoperative right ventricular assistance following the Fontan procedure for tricuspid atresia.

A method of temporary intraoperative right ventricular assistance following the Fontan procedure is described in this case report. The multiple etiologic factors and avenues of treatment for postoperative right ventricular failure are discussed.

Use of a composite Biomer-butyl rubber/Biomer material to prevent transdiaphragmatic water permeation during long-term, electrically-actuated left ventricular assist device (LVAD) pumping.

The pumping diaphragm of the Texas Heart Institute (THI) E-Type ALVAD must perform the dual functions of providing a flexible blood interface and isolating the electrical actuator from adjacent fluids. Thus, protection is required against fluid leakage and moisture diffusion to prevent corrosion and damage to electrical actuator components. Average diffusion rates up to 1 ml per day through currently used elastomeric diaphragm materials have been measured during static in-vitro and in-vivo tests. To circumvent this problem, an improved pumping diaphragm has been recently developed for use with the electrically-actuated THI E-Type ALVAD. This trilaminar diaphragm consists of a composite Biomer and butyl rubber design. A.010 inch layer of butyl rubber (characterized by an extremely low diffusion rate for water, approximately 0 ml per day) is positioned between two Biomer layers (.020 and.010 inches in thickness). Initial invitro and in-vivo studies, in calves, indicate that this composite diaphragm provides an excellent barrier to water permeation, without sacrificing biocompatibility or structural integrity under conditions of chronic flexure.

Transascending aortic intraaortic balloon insertion with delayed sternal closure: A retrospective analysis.

Intraaortic balloon pumping (IABP) is an established therapeutic adjunct in the treatment of postcardiotomy/infarction low cardiac output states. Although the common femoral or iliac arteries are the preferred sites for balloon insertion, severe arterial occlusive disease may preclude entry by these methods. To circumvent this problem, alternative methods of insertion utilizing transthoracic approaches have evolved. In our institution, direct (transaortic) IABP insertion, combined with delayed sternal closure to avoid cardiac compression and possible tamponade, was performed in 28 adult postcardiotomy patients (mean age 60.4 +/- 3 years). The severity of generalized atherosclerosis was reflected in an overall survival rate of 28.6%. Retrospective analyses of the clinical courses of these patients revealed that the transaortic approach allowed utilization of larger and more effective balloons. Successful insertion of 30 and 40 ml balloons was accomplished in 27 of 28 (96%) of these patients, and one patient with a hypoplastic aorta required a 20 ml balloon. There were no complications directly attributable to this alternative site of balloon insertion, and tamponade was avoided. Delayed sternal closure was accomplished within 48 to 96 hours. We concluded that when severe peripheral vascular occlusive disease prevents insertion of intraaortic balloons via the femoral or iliac arteries in patients with low cardiac output, the alternative transaortic approach is indicated. Combined with delayed sternal closure in patients with postcardiotomy dilatation, additional benefits accrue.

Combined replacement of the ascending aorta and the aortic valve in 42 consecutive patients: A comparison of composite graft techniques and conventional techniques over one year.

During 1978, 42 consecutive patients underwent simultaneous aortic valve and ascending aorta replacement in our institution. Seventy-one percent were at low risk despite a high incidence of dissection. Twenty-nine percent were high-risk patients requiring repeat or concomitant cardiac procedures, mostly on an emergency basis. Depending upon the extent of the disease at the aortic root, either of two surgical approaches was used: (1) conventional aortic valve and supracoronary ascending aorta replacement, with or without right coronary artery ostium reimplantation, or (2) insertion of a composite graft containing an aortic valve prosthesis, with reconstruction of both coronary arteries. Preservation of coronary ostia was possible in 85% of the patients, and composite grafts were used in 15%. The conventional method was associated with a higher percentage of survivors. This technique was found to be satisfactory unless severe dilatation or complete destruction of the aortic annulus made composite grafting necessary. The latter technique was associated with fewer re-explorations for postoperative hemorrhage. Both procedures were equally effective, resulting in an operative mortality of 10% in uncomplicated situations. Surgery appeared to offer the only chance of survival for the high-risk group, and half of these patients were salvaged.

Late ventricular fibrillation following successful resuscitation from postinfarction cardiogenic shock with intraaortic balloon pumping.

Early ventricular fibrillation occurs in approximately 5% of patients admitted for acute myocardial infarction. Although late ventricular fibrillation (> 48 hours postinfarction) may occur in stable patients, it occurs more commonly when severe left ventricular power failure is present. We have encountered late ventricular fibrillation in three of 42 (7%) patients treated with intraaortic balloon pumping (IABP) for profound cardiogenic shock secondary to myocardial infarction. These patients progressed to our hemodynamic Class A prior to weaning, and were thought to be stable prior to IABP removal. They were the only ones who expired after achieving Class A status. The episodes of late ventricular fibrillation occurred after the patients had been successfully weaned from IABP and were free of arrhythmias. This experience suggests that prolonged antiarrhythmic therapy may be indicated for postinfarction patients who have had ventricular dysrhythmias during IABP support.

Iatrogenic ascending aortic dissection following cannulation for arterial return and for infusion of cardioplegic solution: Prevention and repair.

Two patients are presented in whom dissection of the ascending aorta resulted from cannulation for arterial return and from the infusion of cardioplegic solution. The dissections were recognized promptly. Following dissection in the first patient, the femoral artery was used to reestablish systemic perfusion. The aortic valve and dissected ascending aorta were replaced, and three vessels were grafted. In the second patient, the dissected anterior wall of the ascending aorta was excised and replaced with a low-porosity Dacron patch into which the proximal aortocoronary anastomoses were inserted. Predisposing factors are discussed, along with preventive measures and methods of repair.

POST-TRAUMATIC APICAL LEFT VENTRICULAR ANEURYSM IN A PATIENT WITH LEFT VENTRICULAR APICAL-ABDOMINAL AORTIC CONDUIT: CASE PRESENTATION.

A patient with a small aortic annulus had an apico-aortic conduit implanted for aortic stenosis approximately three years before being admitted to our institution. Four months after sustaining a steering wheel injury to the chest, he developed chest pain and palpitations. X-ray films and left ventriculograms revealed a large apical aneurysm of unknown duration. At surgery, it was noted that the proximal portion of the conduit had been sewn directly to the myocardium without the use of a rigid or soft apical outlet prosthesis incorporating a sewing ring. The aneurysm was resected along with a small proximal segment of the conduit graft. A polished Pyrolite(R) rigid inlet tube with a sewing ring and graft extension was inserted into the residual left ventricular apex, and continuity was reestablished with the abdominal segment of the conduit. It is postulated that the aneurysm was caused by either the direct anastomosis of the fabric graft to the apical myocardium at the original operation (with subsequent disruption and aneurysm formation prior to the steering wheel injury), or was the result of fixation of the heart at the diaphragm by the conduit, with increased vulnerability to deceleration injury at the direct left ventricular apex myocardium-fabric graft site.

CREATION OF A SECONDARY VENTRICULAR OUTLET TO REVERSE HEMOLYSIS AFTER AORTIC VALVE REPLACEMENT.

A 66-year-old woman developed severe hemolysis after undergoing aortic valve replacement. A diminutive annulus and extensive calcification of the aorta precluded further surgery of the aortic root. Hemolysis was completely reversed by the implantation of a woven Dacron apicoabdominal aortic conduit incorporating a Cooley-Cutter prosthetic valve. Fractionation of stroke volume by means of a second ventricular outlet can reduce shear stresses and turbulence associated with unfavorable hemodynamic conditions, thereby successfully correcting hemolysis.

SEQUENTIAL ELECTROCARDIOGRAPHIC ANALYSIS OF STONE HEART SYNDROME IN A PATIENT SUPPORTED SIX DAYS WITH AN ABDOMINAL LEFT VENTRICULAR ASSIST DEVICE (ALVAD).

A 21-year-old male patient underwent aortic and mitral valve replacement for progressive cardiac failure due to acute bacterial endocarditis. Ischemic myocardial contracture developed during attempts to restore cardiac activity following hypothermic, ischemic, cardioplegic arrest. An abdominal left ventricular assist device (ALVAD) was implanted and supported the circulation for nearly six days prior to cardiac transplantation. The preoperative EKG showed sinus tachycardia with left anterior hemiblock. Postoperatively, there was complete electromechanical dissociation. The postoperative EKG showed a superior and leftward shift of the axis. There was a marked loss of QRS voltage and variable degrees of atrioventricular block. At times, only P waves were present. On the fourth postoperative day, there was an axis shift to the extreme right. Prior to transplantation, sinus rhythm returned, and the axis shifted leftward once again. The common denominator of all the abnormal postoperative electrocardiograms was the conspicuous low voltage that probably signified early and extensive myocardial damage. To our knowledge, this is the first instance wherein a sequential electrocardiographic analysis of stone heart syndrome has been undertaken.