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R L Kormos

Publications and source records attributed to R L Kormos.

At least 73 records · Page 4Linked to original sources
PubMed1996

Medical compliance and its predictors in the first year after heart transplantation.

BACKGROUND: Although poor medical compliance is a major risk factor for morbidity and mortality after heart transplantation, no prospective data are available on rates of noncompliance with each component of the posttransplantation regimen. Little is known about the impact of health history, sociodemographic, or perioperative psychosocial variables on long-term compliance. METHODS: Compliance in eight domains was examined in a cohort of 101 heart recipients followed through the first year after transplantation. Patients received detailed interviews at 2, 7, and 12 months after transplantation. Additional corroborative information was obtained from family member interviews and nurse evaluations. Potential predictors of noncompliance were obtained from medical record reviews and from initial patient interviews. Predictors pertained to cardiac-related history, psychiatric history, sociodemographic variables, and perioperative psychosocial status (psychologic adaptation, social supports, coping strategies). RESULTS: Although degree of noncompliance varied across timepoints, rates of persistent noncompliance during the year were as follows: 37% (exercise); 34% (monitoring blood pressure); 20% (medications); 19% (smoking); 18% (diet); 15% (having blood work completed); 9% (clinic attendance); and 6% (heavy drinking). Compliance in most areas worsened significantly (p < 0.05) over time. Background health-related and sociodemographic characteristics showed no significant influence on any area of posttransplantation compliance. Perioperative psychosocial characteristics were strong and significant predictors of noncompliance. CONCLUSIONS: Pretransplantation screening for background and demographic variables may have limited utility for compliance outcomes. Strategies to improve compliance should focus on psychosocial risk factors pertaining to early psychologic reactions to transplantation, the quality of family relationships, and patients' styles of coping. These risk factors are each potentially modifiable through appropriate educational and supportive interventions.

Adolescent↗
PubMed1996

High-resolution fluorescent particle-tracking flow visualization within an intraventricular axial flow left ventricular assist device.

Flow visualization is typically applied in blood pump development to both confirm the design expectations and identify regions that may be predisposed to blood element deposition and trauma. Rotary pumps, in particular, place high demands on the technique chosen to visualize the flow given the limited visual accessibility of the flow path and the high impeller speeds. Fluorescent image-tracking velocimetry currently is used at the University of Pittsburgh Medical Center to visualize flow accurately inside of these pumps both qualitatively and quantitatively. Flow patterns under steady conditions within an intraventricular axial flow, left ventricular assist pump (prototype No. 7, SUN Medical Technology Research Corporation, Nagano, Japan) were investigated using this technique. The flow fields at the impeller-stator interface and at the pump outlet were given specific attention. This allowed the assessment of the fluid dynamics throughout the hydrodynamic design limits of the pump.

Biomechanical Phenomena↗
PubMed1996

Controller for an axial flow blood pump.

A rotary blood pump inherently provides only one noninvasive "observable" parameter (motor current) and allows for only one "controllable" parameter (pump speed.) To maintain the systemic circulation properly, the pump seed must be controlled to sustain appropriate outlet flows and perfusion pressure while preventing pulmonary damage caused by extremes in preload. Steady-state data were collected at repeated intervals during chronic trials of the Nimbus AxiPump (Nimbus, Inc., Rancho Cordova, California, U.S.A.) in sheep (n = 7) and calves (n = 12). For each data set, the pump speed was increased at increments of 500 rpm until left ventricular and left atrial emptying was observed by left atrial pressure diminishing to zero. The effect of decreasing preload was evaluated perioperatively by inferior vena cava occlusion at a constant pump speed. Fourier analysis established a relationship between changes in the pump preload and the power spectra of the pump current waveform. Based on these results, a control method was devised to avoid ventricular collapse and maintain the preload within a physiologic range. The objective of this controller is the minimization of the second and third harmonic of the periodic current waveform. This method is intended to provide a noninvasive regulation of the pump by eliminating the need for extraneous transducers.

Animals↗
PubMed1995

Automated echocardiographic measures of right ventricular area as an index of volume and end-systolic pressure-area relations to assess right ventricular function.

BACKGROUND: On-line determination of right ventricular (RV) volume to assess its function is clinically difficult. Echocardiographic automated border detection measures of left ventricular (LV) cavity area have been shown to reflect changes in volume, and pressure-area relations have been used to estimate LV contractility. The potential for RV cavity area to estimate changes in volume and to assess RV function, however, has not been evaluated. Accordingly, the objective of this study was to determine the relation between echocardiographic automated border-detected RV cross-sectional area and true volume and to assess the potential for end-systolic pressure-area relations to estimate RV function in an isovolumically contracting isolated canine heart preparation. METHODS AND RESULTS: Eight excised dog hearts with both right and left intraventricular balloons were perfused in an ex vivo apparatus in which both ventricular volumes were controlled independently. RV area data from the level of the left midventricular short-axis plane and pressure data were recorded on a computer through a customized hardware and software interface with the ultrasound system. RV volumes were varied from 9.4 +/- 3.9 to 43.8 +/- 6.9 mL at each of three different LV volume ranges (low range, 12.5 +/- 3.8 mL; medium range, 23.9 +/- 5.6 mL; and high range, 37.5 +/- 5.4 mL). The variation of RV area during isovolumic contraction, which we called deformational area change, was considerable (1.49 +/- 0.68 cm2 mean +/- SD) but did not change significantly with changing RV and LV volumes. Linear regression analysis correlated the maximum, minimum, and mean automated border-detected RV area during isovolumic contraction with absolute volume. A predominantly linear relation was observed, with the group mean r = .98 (y = 0.16x + 0.97; SEE = 0.21 cm2). The effect of LV volume on RV area-volume relation was a significant parallel downward shift (P < .05) by increases in LV volume. End-systolic pressure-area and pressure-volume relations using simultaneously RV pressure were both highly linear and covaried with changing LV volume. CONCLUSIONS: Echocardiographic automated border-detected RV area reflects changes in RV volume under a constant LV volume, and the derived end-systolic pressure-area relation has potential for on-line assessment of RV function.

Animals↗
PubMed1995

Solid tumors after heart transplantation: lethality of lung cancer.

BACKGROUND: Prolonged nonspecific immunosuppression after solid-organ transplantation is associated with an increased risk of certain cancers. This study examined the development of solid-organ tumors after cardiac transplantation. METHODS: Thirty-eight solid tumors were identified in 36 (5.9%) of 608 cardiac transplant recipients who survived more than 30 days. Two patients had two types of skin tumors (basal cell and squamous cell). The tumors included the following types: skin (15), lung (10), breast (1), bladder (2), larynx (2), liver (1), parotid (1), testicle (1), uterus (2), melanoma (2), and Merkel's cell (1). Four immunosuppression regimens based on cyclosporin A or FK 506 were used during this period. RESULTS: There was no association between the incidence of solid tumors and the use of lympholytic therapy. After the diagnosis of tumor was made, the actuarial 2-year survival rates of recipients with skin, lung, and other solid tumors were 71%, 22%, and 23%, respectively. Eight of 10 patients with lung cancer were in stage IIIA or higher at the time of diagnosis. CONCLUSION: Skin and lung tumors are the most frequent solid tumors in heart transplant recipients. Skin tumors (except Merkel's cell carcinoma and melanoma) usually have a benign course, whereas lung and other tumors developing in cardiac transplant recipients carry a poor prognosis. Advanced disease stage at the time of diagnosis is responsible for the dismal outcome of recipients in whom solid tumors develop. Close postoperative tumor surveillance after cardiac transplantation is warranted.

Actuarial Analysis↗
PubMed1995

Perioperative donor bone marrow infusion augments chimerism in heart and lung transplant recipients.

BACKGROUND: We and others have demonstrated that a low level of donor cell chimerism was present for years after transplantation in tissues and peripheral blood of heart and lung recipients; it was associated, in the latter, with a lower incidence of chronic rejection. To augment this phenomenon, we initiated a trial combining simultaneous infusion of donor bone marrow with heart or lung allotransplantation. METHODS: Between September 1993 and January 1995, 15 nonconditioned patients received either heart (n = 10) or lung (n = 5) allografts concurrently with an infusion of unmodified donor bone marrow (3.0 x 10(8) cells/kg), and were maintained on immunosuppressive regimen consisting of tacrolimus and steroids. RESULTS: There was no complication associated with the infusion of donor bone marrow. Chimerism was detectable in 73% of bone marrow-augmented patients up to the last sample tested. Of the 5 control recipients who did not receive bone marrow infusion, only 1 had detectable chimerism by flow on postoperative day 15, which dwindled to an undetectable level by postoperative day 36. None of the patients had evidence of donor-specific immune modulation by mixed lymphocyte reaction. CONCLUSIONS: The combined infusion of donor bone marrow and heart or lung transplantation, without preconditioning of the recipient, is safe and is associated with an augmentation of donor cell chimerism.

Adult↗
PubMed1995

Aortic aneurysm in heart transplant recipients.

PURPOSE: The purpose of this study was to define the clinical features of aortic aneurysms occurring in heart transplant recipients. METHODS: Among the 734 patients who have undergone heart transplantation at our institution over the last 14 years, we have identified 12 patients (1.6% incidence) with aortic aneurysms (9 infrarenal, 3 thoracoabdominal), making this the largest reported series of aortic aneurysms (AA) in heart transplant recipients. RESULTS: For nine of the 12 patients with AA (75%), the indication for transplantation was ischemic cardiomyopathy. This indication accounted for only 42% of the overall transplantation group; our data therefore show that the risk of infrarenal AA disease was higher for patients who underwent transplantation for ischemic cardiomyopathy than for other indications (p = 0.02). In two of the patients with thoracoabdominal AA, chronic dissection was identified as the specific AA cause, whereas all of the other patients in the study had nonspecific "atherosclerotic" AAs. All 12 patients were symptom free at the time of initial discovery of the AAs. Two of the patients with infrarenal AA were diagnosed with AAs before transplantation; for the seven remaining patients with infrarenal AAs, the mean time between transplantation and AA discovery was 5.0 years (range 1.2 to 11.8 years). Serial radiologic studies allowed us to determine the AA expansion rate in seven of the 12 patients. This rate varied from 0 to 2.53 cm/yr (mean 1.20 cm/yr; 1.0 cm/yr for infrarenal AA alone). Five patients with infrarenal AA underwent AA repair as the initial treatment. Three others underwent repair after their AAs significantly expanded under observation. Mean AA diameter at the time of repair was 6.9 cm. All three patients with thoracoabdominal AAs died of acute AA rupture before resection could be done, despite their initial asymptomatic state. AA diameters at time of rupture were 3.5, 6.0, and 11 cm. All of the eight patients with AA treated with surgery are alive and well (median follow-up 18 months). The only complication was acute heart transplant rejection, which occurred 11 days after AA repair in one patient. CONCLUSIONS: Our data suggest that AA occurrence is more likely in patients who undergo heart transplantation for ischemic heart disease than for other indications. Careful serial radiologic surveillance is warranted in any heart transplant patient with an AA, because of the apparent potential for more rapid AA expansion in this patient population than in patients who do not undergo transplantation. We conclude that early repair of infrarenal AA is indicated because excellent operative results and low morbidity rates can be achieved. An aggressive approach to thoracoabdominal AAs in this group may also be appropriate because of the apparent propensity to lethal rupture, sometimes at relatively small AA size.

Aged↗
PubMed1995

The need for accurate risk-adjusted measures of outcome in surgery. Lessons learned through coronary artery bypass.

OBJECTIVE: The authors review the Pennsylvania Health Care Cost Containment Council reports on coronary artery surgery and compare this reporting structure to others, including the Society for Thoracic Surgeons database, currently used by their own program. The authors review the growing likelihood of a need for outcome measures for all of the surgical subspecialties. SUMMARY AND BACKGROUND DATA: Pressure from consumers and insurers will require surgical specialties to be graded by objective outcome measures. Practitioners must be prepared and become involved in the process. METHODS: The authors reviewed the data, which grades all of Pennsylvania's hospitals at which coronary artery bypass is performed. Apparently, the major risk factors commonly employed in most other risk adjustment schemes for cardiac surgery have been deleted, and the practitioners might be judged unfairly. The Pennsylvania system appears to be insurance driven to reward low-cost providers who operate on patients with the lowest risk. RESULTS: Review of data suggests that the Pennsylvania Health Care Cost Containment Council's annual publication, A Consumer's Guide for Coronary Artery Bypass Surgery, misrepresents fair risk adjustment in favor of lower-risk patients, thereby encouraging better score cards for those institutions with patients who are less ill. Data regarding charges for the procedure have not been risk adjusted or related to a regional economic index. CONCLUSIONS: Surgeons must prepare to better understand relevant models that evaluate outcome. Cardiothoracic surgery is one of the first specialties to feel the pressures of mandated evaluations, and the lessons learned in Pennsylvania should be applicable to other states and their practitioners.

Coronary Artery Bypass↗
PubMed1995

An improved left ventricular cannula for chronic dynamic blood pump support.

Ventricular unloading with dynamic blood pumps can be markedly affected by the geometry of the cannula tip within the ventricular chamber. Due to the ability of these pumps to develop significant negative inflow pressure, existing cannula tips designed for passively filling blood pumps can be predisposed to inflow occlusion by intraventricular anatomic structures. A novel "trumpet" mouth cannula was constructed to overcome this limiting problem. This design was based on two criteria: to provide additional stenting to the ventricular apex, and to assure placement of the tip opening relative to the endocardial surface. This prototype cannula was evaluated in vivo against conventional caged, blunt, and tapered designs to assess anatomic and hemodynamic interaction within the ventricular apex. Post mortem examination revealed the inflow tract to be devoid of myocardial obstruction in all cases. These initial studies indicate that a trumpet mouth cannula can provide satisfactory hemodynamic performance required by dynamic blood pumps.

Animals↗
PubMed1995

Neurohormonal activation and exercise function in patients with severe heart failure and patients with left ventricular assist system. A comparative study.

OBJECTIVES: The aim of this study was to evaluate the effects of implantation of a left ventricular assist system (LVAS) on the neurohormonal status, exercise capacity and symptomatic state in patients with severe congestive heart failure (CHF). BACKGROUND: Severe CHF is characterized by decreased exercise tolerance and activation of several neurohormonal systems. METHODS: Parameters of neurohormonal activation and exercise capacity in patients with LVAS (n = 7) were compared with those in groups of New York Heart Association (NYHA) class 3 (n = 121) and class 4 (n = 81) patients. Plasma levels of norepinephrine (NE), plasma renin activity (PRA), and atrial natriuretic peptide (ANP) and maximal and submaximal exercise capacities were measured monthly in LVAS patients and compared with results in CHF patients. RESULTS: Plasma NE and PRA levels were significantly lower in LVAS patients than in NYHA class 4 patients, and plasma ANP levels in LVAS patients were significantly lower than those in NYHA class 3 and 4 patients. The distance walked during submaximal exercise testing and peak oxygen consumption during maximal exercise testing were similar for the LVAS and NYHA class 3 patients. The class 4 patients were unable to exercise. CONCLUSIONS: We conclude that the LVAS lessens the neurohormonal activation and exercise intolerance characteristic of the CHF state and that the exercise capacity early after LVAS (< 4 months) is similar to that observed in NYHA class 3 patients.

Adolescent↗
PubMed1994

Estimation of left ventricular compliance using on-line echocardiographic automated border detection and pressure data.

The end-diastolic pressure-volume relationship can be used to describe left ventricular (LV) compliance. The objective of this study was to utilize measurements of LV cavity area by echocardiographic automated border detection and pressure data to estimate the end-diastolic pressure-volume curve in an isolated heart preparation where true volume could be measured by an intraventricular balloon. Six dog hearts were excised for placement of an intraventricular balloon and a micromanometer catheter and perfused in an ex vivo circuit. Mid-ventricular short-axis images were used to measure cross-sectional area by automated border detection while LV volumes were increased from 5 ml to maximal volume (30-40 ml) in each preparation. Simultaneous area and pressure data were recorded on a computer workstation through a customized interface with the ultrasound system. Three runs of varying LV volumes at 1 ml increments were performed on each of 6 hearts for a total of 1,080 simultaneous measurements. Pressure-volume and pressure-area curves were analyzed by linear regression analyses, the slope of which was used to estimate compliance. End-diastolic pressure-area and pressure-volume relationships were significantly correlated with mean r = 0.97 +/- 0.02 (p < 0.001) from individual hearts. The slopes which served to estimate compliance of the individual pressure-area and pressure-volume curves were similar and differed by only 7 +/- 4%. A similar correlation was observed by second order regression analyses with r = 0.97 +/- 0.01 (p < 0.001) for pressure-area and r = 0.98 +/- 0.01 (p < 0.001) for pressure-volume relationships.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Chronic mechanical circulatory support: rehabilitation, low morbidity, and superior survival.

Because of donor scarcity, 12 (39%) of a series of 31 Novacor left ventricular assist system recipients required mechanical circulatory support for an average of 125 days before transplantation (range, 61 to 303 days). Ten received a heart transplant and all survived to discharge. Two died of infection before transplantation after 93 and 303 days of support. Significant reductions were noted from preimplantation values of right and left cardiac filling pressures. Right ventricular ejection fraction and cardiac index increased. The 4-month actuarial freedom from infection during support was 75%. Three patients benefited from chronic outpatient housing for 5, 18, and 131 days, respectively, with improvements in quality of life measures. Ten chronically supported patients participated in an intensive rehabilitative exercise program resulting in an improvement of New York Heart Association class from IV to I in 9 patients. Mean oxygen consumption, which was 10 mL.kg-1.min-1 30 days after implantation (mean exercise time, 10 minutes) had risen to 15 mL.kg-1.min-1 before transplantation (mean exercise time, 16 minutes). This series suggests that long-term circulatory support is compatible with low morbidity, significant physical and hemodynamic rehabilitation, and an outpatient setting.

Adolescent↗
PubMed1994

Effect of cardiopulmonary bypass on early graft dysfunction in clinical lung transplantation.

The records of 100 lung transplant recipients (13 heart-lungs, 45 double-lungs, and 42 single-lungs) from September 1990 through April 1992 were reviewed to determine the role of cardiopulmonary bypass (CPB) in early graft dysfunction. Fifty-five patients requiring CPB (CPB group) for 186 +/- 54 minutes were compared with the 45 patients without CPB (no-CPB group). All of the heart-lung and en-bloc double-lung transplantations were performed under CPB, with pulmonary vascular lung disease the principal diagnosis, resulting in a significantly younger age population in the CPB group. All other donor- and recipient-related factors matched well in both groups. Of 38 bilateral single-lung transplantations, CPB was used in 18. In double-lung and heart-lung recipients gas exchange of the allografts was evaluated by the arterial/alveolar oxygen tension ratios at nine intervals during the first 72 hours. The mean arterial/alveolar oxygen tension ratio in the CPB group was 0.48 +/- 0.19, significantly lower than in the no-CPB group with 0.60 +/- 0.22 (p = 0.025). All patients had radiographic interpretation and scoring of pulmonary infiltrates from chest roentgenograms taken within 12 hours after reperfusion. The CPB group had more severe pulmonary infiltrates than the no-CPB group (p = 0.034). Prolonged intubation defined as 7 days or longer occurred significantly more often (29/55) in the CPB group than in the no-CPB group (8/45) (p = 0.003). Actuarial graft and patient survival at 1 month was better in the no-CPB group than in the CPB group (42/45 versus 44/55 [p = 0.05] and 43/45 versus 45/55 [p = 0.033], respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Risk stratification using the Society of Thoracic Surgeons Program.

In an era of progressive cost containment and public scrutiny, the wisdom of aggressive surgical therapy for high-risk candidates has been questioned. At our center in the previous 24 months, 728 patients with coronary artery disease were entered into The Society of Thoracic Surgeons national database, and the hospital outcomes plus length of stay were analyzed. Patients were separated according to the predicted mortality based on the groupings in The Society of Thoracic Surgeons database: 0 to 5% (453 patients); 5% to 10% (126 patients); 10% to 20% (96 patients); 20% to 30% (17 patients); and 30% and greater (36 patients). There was a close correlation with the predicted rates of mortality. Importantly, the preoperative risk stratification demonstrated a strong correlation with the significant morbidity and excessive length of stay in the highest-risk groups (predicted risk of 20% to > or = 30%). The incidences of the most common complications in the group with the highest predicted risk (> or = 30%) were 28%, renal failure; 33%, ventilator dependence; and 17%, cardiac arrest. In addition, at short-term follow-up (6 to 8 months), a 24.3% mortality was identified in patients with a predicted mortality that exceeded 20%. These data quantify the risks and morbidities associated with the care of seriously ill patients with coronary artery disease and demonstrate the need for professional and public discussions focusing on the association of a high preoperative risk status and the consumption of resources.

Aged↗
PubMed1994

Cardiac transplantation at the University of Pittsburgh: 1994 update.

During the past 14 years, 746 hearts have been transplanted at the University of Pittsburgh. Immunosuppression has evolved from a CsA-based protocol with or without lympholytic prophylaxis to a tacrolimus-based protocol. Tacrolimus offers comparable survival to the conventional immunosuppression but is associated with lesser side effects and lower recurrent rejection. It also serves as an effective rescue agent for intractable rejection in patients receiving CsA-based immunosuppression. However, the shortage of donors, chronic rejection, and the morbidity associated with chronic use of nonspecific immunosuppression remain the major limitations in clinical transplantation. Currently, research at the University of Pittsburgh focuses on the induction of donor-specific transplantation tolerance in order to eliminate the morbidity associated with nonspecific immunosuppression and on left ventricular-assist devices as a bridge and/or an alternative to cardiac transplantation.

Actuarial Analysis↗
PubMed1993

Preoperative pulmonary hemodynamics and early mortality after orthotopic cardiac transplantation: the Pittsburgh experience.

The influence of preoperative transpulmonary pressure gradient (TPG) and pulmonary vascular resistance (PVR) on early post-transplant mortality was evaluated in 425 orthotopic transplant recipients. The overall 30-day post-transplant mortality rate was 12.5%; the majority of the deaths (52.8%) were due to primary allograft failure. The 0- to 2-day mortality rate was threefold higher in patients with severe preoperative pulmonary hypertension (TPG > or = 15 mm Hg or PVR > or = 5 Wood units), whereas the 3- to 7-day and 8- to 30-day mortality rates were similar. Early post-transplant mortality (0 to 2 days and 8 to 30 days) was also significantly higher (15.9% vs 3.9% and 9.9% vs 2.8%, respectively; p < 0.05) in women compared with men. Women with severe preoperative pulmonary hypertension had higher (p < 0.05) 0- to 2-day post-transplant mortality than comparable men. According to univariate analysis, recipients with preoperative TPG > or = 15 mm Hg had a significantly higher 30-day postoperative mortality rate, irrespective of their level of PVR. Furthermore, patients with severe preoperative pulmonary hypertension who underwent transplantation between 1980 and 1987 had a higher 0- to 2-day post-transplant mortality rate compared with patients operated on after that time. Multiple logistic regression analysis identified female recipient sex and preoperative TPG but not preoperative PVR, era of transplantation, or recipient age as significant (p < 0.001 and p < 0.01, respectively) independent predictors of early post-transplant mortality.

Adolescent↗