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.

AN INTRACORPOREAL (ABDOMINAL) LEFT VENTRICULAR ASSIST DEVICE [ALVAD], XXX: CLINICAL READINESS AND INITIAL TRIALS IN MAN.

The purpose of this report is to present documenting evidence of the clinical readiness of an abdominal left ventricular assist device (ALVAD) according to NHLI criteria,( double dagger ) and the initiation of clinical trials of this device in otherwise irretrievable adult post-cardiotomy patients at the Texas Heart Institute of St. Luke's Episcopal and Texas Children's Hospitals. The ALVAD system has been developed, modified, and improved under NHLI auspices over the last eight years,( double dagger double dagger ) with annual reviews. Over 20,000 hours of in-vivo testing in the calf have been accomplished in our laboratories. The current clinical trials underwent two federal reviews (May 22, 1973 and October 17, 1974) and were the topic of an Ad Hoc Workshop at NHLI on October 28, 1973.( double dagger double dagger double dagger ) More recently, a consecutive series of 26 bovine ALVAD implantations were undertaken; acute and chronic hemodynamic effectiveness with maintenance or augmentation of the systemic circulation during profound ventricular unloading without undue blood trauma, intra-or extra-prosthetic thrombosis, or sepsis was demonstrated; no biomaterials problems were encountered. In-vivo realibility and durability, histologic and pathologic results were detailed, summarized, and submitted to NHLI. Patient acceptability surveys and geometric and volumetric human configuration studies were analyzed. Categorizations of the patients at risk in our institutions and the needs for such a device were documented. The periods of intended use (two weeks-one month), weaning procedures, and the possibility of pump dependence have been discussed. The legal, moral, ethical and informed consent issues were addressed. Clinical protocols (anesthesia, surgical, cardiologic, hematologic, engineering, computerized data-acquisition, follow-up) and cost analyses were developed. The device has now been used in four terminal patients since December, 1975; all subsequently succumbed, but their circulations were temporarily supported during total left ventricular unloading for periods up to eight hours. Continued systematic, controlled clinical investigations of this nature are warranted. A comprehensive listing of pertinent references is included.

REPEAT STERNOTOMY: AN IMPROVED SURGICAL TECHNIQUE.

An improved method of opening the sternum for intracardiac or extracardiac procedures following one or more previous midline sternotomies is described. In our institution, the Stryker(R) pneumatically-driven(*) Sagittal Saw with right-angled blade is used. During the past two years, approximately 75 repeat sternotomies have been performed, and in no instance has a cardiac chamber or great vessel been injured.

APICAL LEFT VENTRICULAR-ABDOMINAL AORTIC COMPOSITE CONDUITS FOR LEFT VENTRICULAR OUTFLOW OBSTRUCTIONS.

Certain problems related to the left ventricular outflow tract are not amenable to conventional surgical methods, but may be solved with the creation of a double outlet left ventricle by using a composite rigid pyrolite left ventricular apex outlet prosthesis and a fabric valve-containing conduit. Low porosity woven Dacron tube grafts are used for the conduit. Twenty-three patients who have undergone apico-aortic bypass with this conduit are reported here, with gratifying results in eighteen.

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.

COMBINED REPLACEMENT OF THE AORTIC VALVE AND ASCENDING AORTA IN JEHOVAH'S WITNESSES: REPORT OF TWO CASES.

Two Jehovah's Witnesses with large ascending thoracic aortic aneurysms and aortic insufficiency secondary to annuloaortic ectasia underwent successful combined replacement of the aortic valve and the ascending aorta. One patient received a composite graft containing an aortic valve prosthesis, which necessitated supravalvular coronary ostia reimplantation; the other patient underwent separate aortic valve and left supracoronary ascending aneurysm replacement, with reimplantation of the right coronary ostium into the graft. No blood or blood derivatives were administered. Both patients had uneventful recoveries and continue to do well. To our knowledge, they represent the first reported cases of successful combined replacement of the aortic valve and ascending aorta in Jehovah's Witnesses.

SUCCESSFUL AORTOCORONARY BYPASS SURGERY IN A PATIENT WITH CLASSICAL HEMOPHILIA A.

A patient with documented Factor VIII deficiency (classical Hemophilia A) and a history of previous severe intra- and postoperative hemorrhage and transfusion reaction underwent myocardial revascularization for advanced triple vessel coronary artery occlusive disease. The coagulation status was investigated, and a replacement regimen was instituted. The surgical procedure and postoperative course were uneventful.

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.

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.

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.

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.

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.

ULTRASTRUCTURAL ANALYSES OF BLOOD-INTERFACING LININGS FORMED WITHIN PARTIAL ARTIFICIAL HEARTS OR ABDOMINAL LEFT VENTRICULAR ASSIST DEVICES: A QUALITATIVE SCHEME FOR HUMAN PSEUDONEOINTIMAL ACCRETION KINETICS.

Following each of 21 clinical trials with the partial artificial heart or abdominal left ventricular assist device (ALVAD), we have examined the blood-interfacing human pseudoneointimal (PNI) linings formed on the fibril-flocked pumping surface by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The salient results of these ultrastructural analyses can be summarized: (1) early PNI accretion kinetics (< 24 hrs) involve plasma protein adsorption, entrapment of erythrocytes, platelets, lymphocytes, numerous neutrophils and macrophages, and the deposition of fibrin within fibril flock interstices (TEM); (2) the surface (< 24 hrs) consists of interconnected fibrin strands (SEM); (3) later PNI accretion kinetics (1-6 days) involve the formation of alternating cellular and fibrin layers (TEM); (4) the surface (1-6 days) consists of cellular aggregates (inter-membrane distances of 340 A) simulating an endothelial interface (SEM, TEM). Based on these analyses, a plausible sequence of events for human PNI accretion kinetics can be advanced, i.e., 0-24 hrs: (a) maximal foreign body response of blood in contact with Dacron fibrils, (b) cellular lysis and fibrin compaction; 1-6 days: (c) accretion and lysis of cellular aggregates (neutrophils, macrophages) 3-4micro thick, (d) accretion of linear fibrin aggregates, 8-10micro thick, and (e) cyclic replication (up to six) of phases c and d.

MACROSCOPIC, MICROSCOPIC, AND MECHANICAL ANALYSES OF PROTOTYPE DOUBLE VELOUR VASCULAR GRAFTS.

In-vivo and ex-vivo evaluations of two prototype double velour tube grafts have been conducted. The experimental grafts were fabricated from terry cloth derivatives of the Dacron polyester material that is used in the construction of presently available Microvel(R) Double Velour and Cooley Double Velour Guideline(R) grafts.(*) The use of terry cloth derivatives in the experimental grafts provides a velour pile that is more uniform in height and density than current clinical grafts. The hypothesis examined by these studies was whether the utilization of terry cloth derivatives provides a more perfect capsular and luminal surface for fibrous tissue attachment and ingrowth, thereby enhancing neointimal formation at the blood contacting surface. Using standard techniques, prototype grafts were implanted in the abdominal aortas of dogs for test periods of 1 to 6 months. All grafts remained patent throughout the healing period. At explantation, the macroscopic and microscopic properties of the grafts were examined and characterized. Neointimal analysis demonstrated that the lighter denier, higher porosity prototype consistently produced more homogeneous blood-contacting surfaces with smoother contours and more complete endothelialization than the heavier denier, lower porosity prototype. From these analyses, we can conclude that both prototype grafts possess the basic properties of useful arterial prostheses. They are not prone to early thrombosis, and exhibit rapid healing properties. This study indicates that the use of terry cloth derivatives provides a more uniform, less random velour pile and that arterial grafts constructed from such materials produce more uniform and biologically stable neointimas.

DELAYED STERNAL CLOSURE: A USEFUL TECHNIQUE TO PREVENT TAMPONADE OR COMPRESSION OF THE HEART.

Closure of the sternotomy incision was limited to the skin in four critically ill patients following cardiopulmonary bypass. One patient had sustained an intractable bleeding diathesis and the other three had ventricular distention which prevented approximation of the sternum. All patients survived after delayed closure and repair of the sternotomy. Delayed primary closure of the sternum is a useful maneuver after cardiac surgery when routine closure would jeopardize early recovery.

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.