Biomedical subjects

M A Hamilton

Publications and source records attributed to M A Hamilton.

At least 55 records · Page 3Linked to original sources

PubMed1995

Target heart failure populations for newer therapies.

BACKGROUND: The scarcity of donor hearts has created a large population of heart failure patients who are unlikely to undergo transplantation. Newer surgical therapies that might sustain such patients at home previously have been applied in critical situations in which early outcome is jeopardized by multiorgan failure. The optimal population for studies of extended support would be ambulatory patients with low operative risk but high risk of later unfavorable outcome. METHODS AND RESULTS: Baseline clinical, echocardiographic, and hemodynamic data were collected prospectively between 1988 and 1993 in 500 patients who were discharged on tailored medical therapy after evaluation for transplantation. Specific criteria were examined to identify high risk of death or need for urgent transplantation during the next 2 years. In 265 patients with ejection fraction < or = 25% and initial New York Heart Association class IV symptoms, survival at 2 years was 55% (without urgent transplantation, 45%). Lower cardiac index or higher filling pressures at the time of referral did not confer higher risk, which was predicted by persistence of higher pressures after therapy. Serum sodium below 133 was associated with 34% 2-year survival without urgent transplantation, and ventricular dimension > 80 mm with a rate of 25%. Patients with initial peak oxygen consumption > 10 mL/kg per minute had a 2-year event-free rate of 72% compared with 48% for those with < 10 mL/kg per minute and 32% for those unable to exercise at referral. Demonstration of a 30% decrease in mortality with a controlled trial of new therapy in patients with ejection fraction < or = 25% would require 600 patients with class III symptoms or almost 300 patients with class IV symptoms unless another criterion were added. CONCLUSIONS: Ambulatory populations with high predicted event rates can be identified at initial evaluation, when hemodynamic criteria may be less useful than ventricular dimension, serum sodium, and ability to exercise. The use of outcome data from previous eras may lead to overestimation of benefits from newer therapies and underestimation of the sample size required in a prospective trials.

Cardiac Output, Low↗

PubMed1995

Evidence for preserved cardiopulmonary baroreflex control of renal cortical blood flow in humans with advanced heart failure. A positron emission tomography study.

BACKGROUND: The effect of cardiopulmonary baroreflexes on the renal circulation in healthy humans and patients with heart failure is unknown because of the technical limitations of studying the renal circulation. Positron emission tomography (PET) imaging is a new method to measure renal cortical blood flow in humans that is precise, rapid, reproducible, and noninvasive. The purpose of this study was to compare the effect of acute cardiopulmonary baroreceptor unloading by phlebotomy on regional blood flow in healthy humans and humans with advanced heart failure. METHODS AND RESULTS: We compared renal cortical blood flow and forearm blood flow in 10 healthy volunteers and 8 patients with heart failure (left ventricular ejection fraction, 0.24 +/- 0.02) during cardiopulmonary baroreceptor unloading with phlebotomy (450 mL). The major findings of this study are: (1) At rest, renal cortical blood flow is markedly diminished in humans with heart failure compared with healthy humans (heart failure, 2.4 +/- 0.1 versus healthy, 4.3 +/- 0.2 mL.min-1.g-1, P < .001). (2) In healthy humans, during phlebotomy, forearm blood flow decreased substantially (basal, 3.3 +/- 0.4 versus phlebotomy, 2.6 +/- 0.3 mL.min-1.100 mL-1, P = .02) and renal cortical blood flow decreased slightly but significantly (basal, 4.3 +/- 0.2 versus phlebotomy, 4.0 +/- 0.3 mL.min-1.g-1, P = .01). (3) The small magnitude of reflex renal vasoconstriction is not explained by the inability of the renal circulation to vasoconstrict, since the cold pressor stimulus induced substantial decreases in renal cortical blood flow in healthy subjects (basal, 4.4 +/- 0.1 versus cold pressor, 3.7 +/- 0.1 mL.min-1.g-1, P = .003). (4) In humans with heart failure, during phlebotomy, forearm blood flow did not change (basal, 2.6 +/- 0.3 versus phlebotomy, 2.7 +/- 0.2 mL.min-1.100 mL-1, P = NS), but renal cortical blood flow decreased slightly but significantly (basal, 2.4 +/- 0.1 versus phlebotomy, 2.1 +/- 0.1 mL.min-1.g-1, P = .01). (5) The cold pressor stimulus induced substantial decreases in renal cortical blood flow in patients with heart failure (basal, 2.9 +/- 0.1 versus cold pressor, 2.3 +/- 0.1 mL.min-1.g-1, P = .008). Thus, in patients with heart failure, there is an abnormality in cardiopulmonary baroreflex control of the forearm circulation but not the renal circulation. CONCLUSIONS: This study demonstrates the power of PET imaging to study normal physiological and pathophysiological reflex control of the renal circulation in humans and describes the novel finding of selective dysfunction of cardiopulmonary baroreflex control of one vascular region but its preservation in another in patients with heart failure.

Adult↗

PubMed1995

Improvement in exercise capacity of candidates awaiting heart transplantation.

OBJECTIVES: This study determined the frequency of improvement in peak oxygen uptake and its role in reevaluation of candidates awaiting heart transplantation. BACKGROUND: Ambulatory candidates for transplantation usually wait > 6 months to undergo the procedure, and during this period symptoms may lessen, and peak oxygen uptake may improve. Whereas initial transplant candidacy is based increasingly on objective criteria, there are no established guidelines for reevaluation to determine who can leave the active waiting list. METHODS: All ambulatory transplant candidates with initial peak oxygen uptake < 14 ml/kg per min were identified. Of 107 such patients listed, 68 survived without early deterioration or transplantation to undergo repeat exercise. A strategy of reevaluation using specific clinical criteria and exercise performance was tested to determine whether patients with improved oxygen uptake could safely be followed without transplantation. RESULTS: In 38 of the 68 patients, peak oxygen uptake increased by > or = 2 ml/kg per min to a level > or = 12 ml/kg per min after 6 +/- 5 months, together with an increase in anaerobic threshold, peak oxygen pulse and exercise heart rate reserve and a decrease in heart rate at rest. Increased peak oxygen uptake was accompanied by stable clinical status without congestion in 31 of 38 patients, and these 31 were taken off the active waiting list. At 2 years, their actuarial survival rate was 100%, and the survival rate without relisting for transplantation was 85%. CONCLUSION: Reevaluation of exercise capacity and clinical status allowed removal of 31 (29%) of 107 ambulatory transplant candidates from the waiting list with excellent early survival despite low peak oxygen uptake on initial testing. The ability to increase peak oxygen uptake, particularly with increased peak oxygen pulse, may indicate improved prognosis as well as functional capacity and, in combination with stable clinical status, may be an indication to defer transplantation in favor of more compromised candidates.

Adolescent↗

PubMed1995

Women and alcohol: current Australian research.

Over the past decade research on women and alcohol has been gaining momentum with evidence of an accumulating data base and a growing section of the drug and alcohol literature specifically addressing this area of interest. Despite the gains made in gender sensitive research on substance use, a review of the literature reveals that many of the articulated concerns are similar to those identified over the preceding 20 years.This paper reports on the findings of an Australian wide survey investigating the current level of research on women and alcohol. The survey was used in conjunction with a critical analysis of the literature to identify gaps in research activity in the area of women and alcohol. Identified research gaps result, in part, from the disproportionate focus on women with severe alcohol problems within treatment facilities. There is a lack of qualitative and quantitative research on women's drinking, whether it be usual use or problematic use, within the general population as a way of bridging the gap between population surveys and clinical studies. In addition, there is a need for longitudinal research to provide information on the context of women's drinking over a several year period, giving insight into the many factors which could be influencing women's drinking behaviour. Finally, the relative lack of commitment to prevention as a research agenda for women needs to be addressed.

Journal Article↗

PubMed1995

The University of California at Los Angeles experience in heart transplantation.

In the last decade, the number of patients undergoing heart transplantation has steadily increased as a result of expanding indications for cardiac transplantation. The limitation on the number of transplants performed has been the number of donor organs available. At UCLA, 511 heart transplant procedures were performed from 1984-1994. The mean number of rejection episodes and infections per patient in the first year after transplant was 1.1+/-1.3 and 1.0+/-1.2, respectively. Actuarial one-, 3-, and 5-year survival rates were 84%, 77% and 73%, respectively. Survival of patients age 60 years and over (n=105) was comparable to that of patients under age 60. Despite transplanting more critically ill patients (Status 1) and having longer cold ischemic times, outcomes have been improving. We have been pursuing corticosteroid-free immunosuppression, which no doubt has led to the decrease in infection complications. Furthermore, our work with pravastatin early after transplantation has led to a decrease in clinically severe rejection episodes which has translated into improved survival. Pravastatin also appeared to decrease the development of transplant coronary artery disease and appeared to have an adjunct immunosuppressive effect in our heart transplant patients on CsA-based immunosuppression. Future studies will include the use of mycophenolate mofetil which has properties against B-lymphocytes in addition to T-lymphocytes to block both humoral and cellular rejection. Our program continues to seek better ways to improve survival and the quality of life of our patient population.

Academic Medical Centers↗

PubMed1994

Prediction of improvement in recent onset cardiomyopathy after referral for heart transplantation.

OBJECTIVES: The purpose of this investigation was to determine how often left ventricular function improves in recent onset dilated cardiomyopathy of sufficient severity to cause referral for heart transplantation and how to predict this improvement at the time of evaluation for transplantation. BACKGROUND: Improvement has been reported to occur frequently in patients with acute dilated cardiomyopathy but has not been described specifically in these patients referred for transplantation. To avoid potentially needless transplantation, it would be useful to know the frequency of improvement and how to predict it in these patients. METHODS: A consecutive series of 297 patients with primary dilated cardiomyopathy evaluated for heart transplantation was reviewed to identify those with onset of heart failure symptoms within the preceding 6 months and to examine their outcome. The clinical, echocardiographic, hemodynamic and laboratory profiles of patients with improvement in left ventricular function (defined as an increase in left ventricular ejection fraction > or = 0.15 to a final ejection fraction of > or = 0.30) were compared with those of patients without improvement to assess which variables might predict improvement. RESULTS: Of 49 patients with recent onset dilated cardiomyopathy, 13 (27%) showed improvement, with an increase in mean left ventricular ejection fraction from 0.22 +/- 0.08 to 0.49 +/- 0.09. All patients with improvement had survived without heart transplantation at 43 +/- 29 months. Survival time was shorter in the remaining 36 patients without improvement with recent onset cardiomyopathy than in the 248 with chronic symptoms (p = 0.03) and in younger compared with older patients with recent onset cardiomyopathy (p = 0.0001). By multivariate analysis, predictors of improvement were shorter duration of symptoms, lower pulmonary wedge and right atrial pressures and higher serum sodium levels. CONCLUSIONS: A minority of patients with dilated cardiomyopathy and symptoms for < or = 6 months will have marked improvement in left ventricular function, after which prognosis is excellent despite previous referral for heart transplantation. Those with symptom duration > 3 months and more severe initial decompensation as reflected by higher filling pressures and lower serum sodium levels are unlikely to show improvement and may require earlier consideration for heart transplantation.

Actuarial Analysis↗

PubMed1994

The impending crisis awaiting cardiac transplantation. Modeling a solution based on selection.

BACKGROUND: Each month, the number of transplant candidates added to the waiting list exceeds the number of transplantations performed, and many outpatients deteriorate to require transplantation urgently. The current list of 2400 candidates and the average wait of 8 months continue to increase. METHODS AND RESULTS: To determine the size at which the outpatient and critical candidate pools will stabilize, population models were constructed using current statistics for donor hearts, candidate listing, sudden death, and outpatient decline to urgent status and revised to predict the impact of alterations in policies of candidate listing. If current practices continue, within 48 months the predicted list will stabilize as the sum of an estimated 270 hospitalized candidates, among whom, together with newly listed urgent candidates, all hearts will be distributed and 3700 outpatient candidates with virtually no chance of transplantation unless they deteriorate to an urgent status. Decreasing the upper age limit now to 55 years would reduce the number listed each month by 30% and result within 48 months in a list of only 1490. The list could also be decreased by 30%, however, if it were possible to list only a candidate group with an 80% chance (compared with 52% estimated currently) of sudden death or deterioration during the next year. With this strategy, the waiting list would equilibrate within 48 months to one-third the current size, with 50% of hearts for outpatient candidates, who would then have an 11% chance each month of receiving a heart compared with 0% if recent policies prevail. Total deaths, with and without transplantation, would be minimized by this rigorous selection of outpatient candidates. CONCLUSIONS: This study implies that immediate provisions should be made to limit candidate listing and revise expectations to reflect the diminishing likelihood of transplantation for outpatient candidates. Future emphasis should be on improved selection of candidates at highest risk without transplantation.

Computer Simulation↗

PubMed1994

Independent control of skin and muscle sympathetic nerve activity in patients with heart failure.

BACKGROUND: Sympathetic excitation characterizes heart failure, but the underlying mechanisms remain unknown. Abnormal baroreflex restraint of sympathetic neural outflow has been proposed, since baroreflexes are known to be abnormal in heart failure. The purpose of this study was to determine if sympathetic activation in humans with heart failure is limited to regions governed by the baroreflexes or is generalized to other regions free from baroreflex control. METHODS AND RESULTS: We report the first direct recordings of skin sympathetic nerve activity (free from baroreflex control) in humans with heart failure and compare simultaneous skin and muscle (baroreflex-dependent) sympathetic peroneal nerve activity in six patients with severe heart failure (mean left ventricular ejection fraction, 0.19 +/- 0.06) and in six age-matched normal control subjects. Although muscle sympathetic nerve activity was markedly increased in heart failure patients (heart failure versus controls, 69 +/- 3 versus 21 +/- 2 bursts per minute; P < .001), skin sympathetic nerve activity was not increased (heart failure versus controls, 12 +/- 1 versus 15 +/- 1 bursts per minute; P = NS). CONCLUSIONS: The finding that skin sympathetic nerve activity in contrast to muscle sympathetic nerve activity is not increased in heart failure supports the concept that an altered reflex system, such as the baroreflexes, with nonuniform effects on muscle and skin sympathetic nerve activity, underlies sympatho-excitation in heart failure.

Adult↗

PubMed1993

Impact of left ventricular cavity size on survival in advanced heart failure.

Although left ventricular (LV) dilation has been assumed to be deleterious, the physiologic significance of severe LV dilation in advanced heart failure and its impact on survival have not been defined. LV end-diastolic dimension was measured by M-mode echocardiography in 382 patients with class III or IV heart failure symptoms (mean LV ejection fraction 20 +/- 8%) referred for evaluation for cardiac transplantation. All patients underwent right-sided heart catheterization, and received vasodilator and diuretic therapy adjusted to hemodynamic goals. Although 183 patients with massive LV dilation by LV index > 4 cm/m2 (LV index = LV end-diastolic dimension/estimated body surface area) had a similar severity of hemodynamic impairment to that of 199 patients with only moderate dilation (LV index < or = 4 cm/m2), with baseline mean cardiac index of 2 liters/m/m2 and mean pulmonary arterial wedge pressure of 26 mm Hg in both groups, their actuarial 2-year survival without transplantation was much lower (49 vs 75%; p = 0.004). In the Cox proportional-hazards model, LV index predicted total and sudden death, independent of etiology of heart failure, ejection fraction and other parameters of disease severity. Follow-up echocardiograms (mean 13 +/- 6 months) in 80 heart failure survivors without transplantation showed an increase in mean LV ejection fraction (22 +/- 8% to 26 +/- 13%), but no change in mean LV index in either the massive or moderately dilated groups. Thus, massive LV dilation is an independent contributor to poor outcome in patients with advanced heart failure, and may be stabilized by aggressive vasodilator and diuretic therapy.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1993

Prevalence and clinical implications of abnormal thyroid hormone metabolism in advanced heart failure.

Patients with advanced congestive heart failure are often severely ill and may experience substantial abnormalities in thyroid hormone metabolism. Thus, we examined this patient population to determine the prevalence and prognostic significance of altered thyroid hormone concentrations, the course of thyroid abnormalities in congestive heart failure survivors, and the potential relationship of thyroid abnormalities to overall metabolic rate. Our results indicate that thyroid hormone metabolism (ie, the triiodothyronine to reverse triiodothyronine ratio) is altered in a majority of patients with advanced congestive heart failure and is an independent predictor of mortality. Currently a study is underway that will provide further evidence for the mechanisms involved in congestive heart failure and abnormal thyroid hormone metabolism.

Basal Metabolism↗

PubMed1993

Sociology-the poor relation in alcohol and drug research?

As a foundation theoretical discipline, sociology has much to offer the multi-disciplinary field of alcohol and drug studies. It has, nevertheless, been overshadowed by others such as medicine and, more recently, psychology. This paper maps significant policy issues in the alcohol and drug field over the past decade using Australian experience as an example. It identifies contributions of the social sciences and in doing so, poses a challenge for sociology.

Journal Article↗

PubMed1993

Cardiac transplantation at UCLA.

In the last decade, the number of patients undergoing heart transplantation has steadily increased as a result of expanding indications for cardiac transplantation. The limitation on the number of transplants performed has been the scarcity of donor organs. At UCLA, 320 heart transplant procedures were performed in adults through the end of 1992; 173 patients (54%) underwent transplantation for ischemic cardiomyopathy; 104 (33%) for dilated cardiomyopathy, and 13 (4%) for severe rejection or cardiac allograft vasculopathy. The mean number of rejection episodes and infections per patient per year in the first posttransplant year was 1.28 and 0.58, respectively. Early mortality (30 days) was 5.7%, while 1-, 3-, and 5-year survival rates were 84.3%, 74.3%, and 67.5%, respectively. Survival of patients transplanted for ischemic cardiomyopathy and idiopathic cardiomyopathy was nearly equal. Survival was also comparable in patients aged 60 years and over (n = 71) and those under age 60. We observed improved patient outcome including shorter posttransplant hospital stay, time to extubation, and lower incidences of infections, rejection episodes, and renal failure in patients transplanted in 1991 and 1992. This observation was interesting in view of the increased proportion of critically ill patients in this group (46% UNOS Status 1) compared with patients transplanted in the previous years (30% UNOS Status 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Academic Medical Centers↗

PubMed1992

Effect of direct vasodilation with hydralazine versus angiotensin-converting enzyme inhibition with captopril on mortality in advanced heart failure: the Hy-C trial.

To compare the benefit of angiotensin-converting enzyme inhibition and direct vasodilation on the prognosis of advanced heart failure, 117 patients evaluated for cardiac transplantation who had severe symptoms and abnormal hemodynamic status at rest were randomized to treatment with either captopril or hydralazine plus isosorbide dinitrate (Hy-C Trial). Comparable hemodynamic effects of the two regimens were sought by titrating vasodilator doses to match the hemodynamic status achieved with nitroprusside and diuretic agents, attempting to achieve a pulmonary capillary wedge pressure of 15 mm Hg and a systemic vascular resistance of 1,200 dynes.s.cm-5. Treatment with the alternate vasodilator was started because of poor hemodynamic response or side effects (40% of patients in the captopril group and 22% in the hydralazine group). Adequate hemodynamic response in patients with a serum sodium level less than 135 mg/dl was more likely with hydralazine than with captopril (71% vs. 33%, p = 0.04). Isosorbide dinitrate was prescribed in 88% of the hydralazine-treated patients and 84% of the captopril-treated patients. The hemodynamic improvements from each regimen were equivalent. After 8 +/- 7 months of follow-up, the actuarial 1-year survival rate was 81% in the captopril-treated patients and 51% in the hydralazine-treated patients (p = 0.05). The improved survival with captopril resulted from a lower rate of sudden death, which occurred in only 3 of 44 captopril-treated patients compared with 17 of 60 hydralazine-treated patients (p = 0.01). In the subset of patients who continued treatment with the initial vasodilator, results were similar to those for the entire treatment group.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗

PubMed1992

Amiodarone therapy does not compromise subsequent heart transplantation.

OBJECTIVES: The objective of this study was to determine the frequency of pulmonary complications, feasibility of early hospital discharge and requirements for postoperative inotropic and chronotropic support in patients receiving amiodarone therapy before heart transplantation. BACKGROUND: Although many patients waiting for heart transplantation will die of arrhythmias before a donor heart is found, the use of amiodarone has been limited by concern about increased complications in the perioperative period. METHODS: The 29 patients receiving amiodarone at the time of heart transplantation at University of California, Los Angeles Medical Center between October 1986 and September 1990 were compared with 29 control recipients to evaluate postoperative morbidity. Patients were receiving amiodarone for recurrent ventricular tachyarrhythmias (n = 11), atrial fibrillation (n = 2) or complex ventricular ectopic activity (n = 16). The average daily dose was 360 +/- 230 mg/day for an average of 11 +/- 22 months before transplantation. Amiodarone and control groups had a similar ejection fraction (0.18 +/- 0.07 vs. 0.20 +/- 0.08), frequency of coronary disease, age and gender. There were three more status I patients in the control group. OKT3 was given to only two patients receiving amiodarone and 12 control patients at high risk for renal dysfunction. RESULTS: Postoperatively, the duration of assisted ventilation was 21 +/- 19 h after amiodarone therapy versus 26 +/- 2 h in the control group (20 +/- 18 h vs. 15 +/- 9 h after excluding patients receiving OKT3), discharge arterial oxygen saturation was > 95% in both groups. Two patients in the amiodarone group with a smoking history of > 100 pack-years developed bilateral pulmonary infiltrates of brief duration. Although patients receiving amiodarone required atrial pacing more frequently (eight vs. two patients) and had a lower heart rate at discharge (75 +/- 18 vs. 86 +/- 11 beats/min), the duration of inotropic support (2.1 +/- 1.5 vs. 3.5 +/- 2.5 days) and of hospital stay (10 +/- 3 vs. 15 +/- 10 days) was not higher in the amiodarone than in the control group. The mortality rate at 30 days was similar in the two groups (6.8% vs. 3.4%, p = NS). CONCLUSIONS: Amiodarone therapy before heart transplantation may contribute to occasional pulmonary complications but does not significantly increase perioperative morbidity or mortality with the regimens used in this retrospective study.

Aged↗

PubMed1992

Modeling distribution of donor hearts to maximize early candidate survival.

BACKGROUND: Priority for cardiac transplantation should reflect the relative waiting list mortality and operative mortality of outpatient candidates and critical candidates. METHODS AND RESULTS: To determine how to distribute donor hearts for maximal overall survival, a Markov model of eight states was constructed from current statistics for outpatient sudden death, deterioration to critical status, operative mortality for outpatients, and operative mortality for critical candidates. Because the fraction of hearts offered to critical candidates varied, expected survival at 1 year was calculated. To determine the factors most critical in determining priority policy, current conditions were then varied over a fourfold range. Priority for critical candidates maximized overall candidate survival (with and without transplantation), increasing 1-year survival to 78% compared with 66% if hearts were offered only to outpatients. The benefit of giving priority to critical patients persisted when current group mortality rates were individually halved or doubled because these rates were still small compared with the 100% expected mortality of critical patients without transplantation. If the outpatient sudden death rate and the operative mortality for critical patients were doubled simultaneously, however, there was a slight negative impact on survival if critical candidates received priority. Regardless of changes in subgroup outcomes, the distribution of donor hearts had a relatively modest impact on survival because of the large excess of candidates. CONCLUSIONS: Critical candidates for transplantation should continue to receive priority even if their operative mortality increases above current levels. However, postoperative outcomes must be assessed in relation to changing pretransplantation risks. Distribution of donor hearts will be most beneficial when it is possible to identify the waiting patients at greatest risk for sudden death and deterioration without transplantation.

Death, Sudden, Cardiac↗

PubMed1991

Sustained reduction in valvular regurgitation and atrial volumes with tailored vasodilator therapy in advanced congestive heart failure secondary to dilated (ischemic or idiopathic) cardiomyopathy.

Afterload reduction therapy can acutely improve hemodynamic function in patients with advanced heart failure; however, it is unknown if initial reductions in mitral and tricuspid regurgitation and atrial volumes can be sustained with oral therapy. Atrial volumes and atrioventricular valve regurgitation were measured using 2-dimensional and Doppler echocardiography with color-flow imaging in 14 patients with dilated heart failure (ejection fraction 17 +/- 4%) before and after 3 +/- 1 days of intensive vasodilator and diuretic therapy tailored to hemodynamic goals. Echocardiography was repeated again after 6 +/- 2 months on oral vasodilators and a flexible diuretic regimen. Acute therapy reduced systemic vascular resistance from 1,760 +/- 460 to 1,010 +/- 310 dynes.s.cm-5, pulmonary artery wedge pressure from 30 +/- 5 to 17 +/- 4 mm Hg, and right atrial pressure from 13 +/- 5 to 7 +/- 3 mm Hg, and led to a 61% increase in stroke volume (from 36 +/- 10 to 58 +/- 14 ml) (p less than 0.01). Mitral and tricuspid regurgitation, determined by color-flow fraction, initially decreased from 0.34 +/- 0.17 to 0.20 +/- 0.20 and from 0.33 +/- 0.15 to 0.13 +/- 0.13, respectively (p less than 0.001). This reduction was sustained at 6 months. Significant decreases occurred with acute therapy, with further reductions at 6 months in both mean left atrial volume (from 100 +/- 25 to 80 +/- 19 to 65 +/- 15 cm3) and right atrial volume (from 85 +/- 23 to 64 +/- 23 to 52 +/- 14 cm3) (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1991

Dentists evaluate their patients: an empirical investigation of preferences.

Dental treatment is a dyadic encounter. Yet research on the dentist-patient dyad has tended to focus on patient perceptions of dentist, to the neglect of dentist perceptions of patient. Previous theoretic and qualitative work on caregiver perceptions of patients suggested three dimensions of evaluation. Dentists (N = 618) rated their patients on items taken from two prior studies. Dentists' responses were subjected to confirmatory factor analysis. The analysis substantiated the existence of three evaluative dimensions: compliance, tractability, and likability. Further analysis showed that the three dimensions formed a Guttman simplex, revealing a second-order factor of selectivity and allowing a classification of dentists on the basis of patient selectivity.

Attitude of Health Personnel↗

PubMed1991

Decreasing survival benefit from cardiac transplantation for outpatients as the waiting list lengthens.

Many patients are accepted for cardiac transplantation during a period of clinical instability associated with a high risk of death, even though most can be discharged home to await transplantation. As the waiting lists lengthen, priority is awarded solely on the basis of the waiting time of outpatients, who now usually undergo transplantation after they have already survived a major period of jeopardy. To determine the impact of the current waiting times and priority system on the previously expected benefit offered by transplantation, 1-year actuarial survival without transplantation was recalculated after each month without transplantation for 214 potential candidates with an ejection fraction of 0.17 +/- 0.05 discharged on tailored medical therapy after evaluation. These data were compared with the 1-year survival data of 88 outpatients who underwent transplantation. Actuarial survival after 1 year was 67% on tailored therapy compared with 88% after transplantation (p = 0.009). Death without transplantation was sudden in 43 of 51 patients, resulting from hemodynamic decompensation in 8. For outpatients already surviving 6 months without transplantation, actuarial survival over the next 12 months was 83% without transplantation. Thus, the expected improvement in survival after transplantation would be only 5% over the subsequent year for patients waiting 6 months, which is the waiting time for many outpatients. Such patients should be reevaluated to determine whether transplantation remains indicated during the next year.

Actuarial Analysis↗