Assessing exercise performance after heart transplantation

OBJECTIVE: Heart transplantation improves the survival rate and quality of life in patients with severe symptoms of congestive heart failure and an ejection fraction of 20% or less. Despite marked symptomatic and clinical improvement in those who undergo heart transplantation, exercise capacity often remains reduced, and the factors limiting exercise performance during the post-transplantation period remain unclear. This study was performed to investigate the factors affecting exercise capacity in heart transplantation recipients. PATIENTS AND METHODS: Fourteen patients with cardiomyopathy were enrolled in this study. We measured peak exercise oxygen uptake (peak VO(2)) in seven patients (age range: 42 +/- 14 yr) 10-28 months after transplantation, in seven patients (age range: 33 +/- 18 yr) with dilated cardiomyopathy before heart transplantation, and in 14 healthy control subjects (age range: 44 +/- 12 yr). The left ventricular ejection fraction, Beck Depression Inventory score, Medical Outcome Health Survey Short Form-36 Questionnaire (SF-36) results, and immunosuppressive therapy administered were recorded in all patient groups. RESULTS: All patients in the post-transplantation group terminated exercise testing before the anaerobic threshold because of general fatigue. All heart transplantation recipients exhibited a left ventricular ejection fraction within the normal range (mean +/- SD = 57% +/- 2%). The peak VO(2) mean values were significantly different among the three groups (p = 0.001). There were statistically significant correlations between the peak VO(2) values and the Beck Depression Inventory scores (r = -0.637, p = 0.01), between the peak VO(2) values and bodily pain (r = 0.717, p = 0.006), between the peak VO(2) values and general health perceptions (r = 0.706, p = 0.007), and between peak VO(2) values and postoperative duration (r = 0.843, p = 0.03) in all patient groups. CONCLUSION: In the long-term treatment of heart transplant recipients, exercise training should be considered an important therapeutic tool that enables patients to achieve a good quality of life.     

Health-related fitness and quality of life following steroid withdrawal in renal transplant recipients

BACKGROUND: Exercise capacity increases significantly soon after transplantation; however, over time it does not further improve and patients remain low compared to normal levels. The limitations to exercise following transplantation have not been identified, but may be related to immunosuppression therapy regimens that include prednisone. METHODS: We studied health-related fitness measures (cardiorespiratory fitness, muscle strength, and body composition) and quality of life in renal transplant recipients randomized into two groups: those using standard maintenance immunosuppression, including prednisone therapy (N = 14); and those undergoing rapid withdrawal of steroids using Simulect[interleukin-2 (IL-2) receptor inhibitor] (N = 9). Testing was done at 3 and 12 months following transplant and the 12-month data were compared to 15 normal sedentary controls. RESULTS: Compared to those maintained on steroids, the steroid withdrawal group showed greater gains in VO2peak (P = 0.05) and quadriceps peak torque (P = 0.05) and greater gains in the vitality score and the Physical Composite Scale on the SF-36 questionnaire (P < 0.05). At 1 year, all patients had significantly lower exercise capacity compared to the sedentary controls (P = 0.01). No differences were observed in body composition, with both patient groups increasing in body weight (primarily body fat) over time. At 12 months, all patients were not different in body fat percentage compared to the sedentary controls. CONCLUSION: We conclude that prednisone is not the cause for increased body fat following transplantation; however, it may contribute to lower spontaneous improvements in exercise capacity possibly by limiting increases in muscle strength. The low exercise capacity in all transplant recipients studied at 1 year suggests a need for exercise training to optimize physical functioning following transplant.     

Predictability and other aspects of post-transplant diabetes mellitus in heart transplant recipients.

BACKGROUND: Diabetes mellitus that develops after organ transplantation may predispose patients to further complications. We studied the value of pre-transplant oral glucose tolerance testing or maximum random plasma glucose, and HLA-DR3 and/or DR4 phenotype as predictors of post-transplantation diabetes mellitus in heart transplant recipients. PATIENTS AND METHODS: In 228 cardiac allograft recipients (median age, 50 years; mean follow-up, 4.77 years), we used either pre-transplant oral glucose tolerance testing results (Group I, n = 141)-excluding patients with pre-existing diabetes (n = 9)--or maximum random plasma glucose values (Group II, n = 78) to study predictability of post-transplant diabetes. In addition, we investigated its relation to rejection treatment and clinical course. RESULTS: Cumulative incidence of post-transplant diabetes (n = 43) was 19.6%, 83% of which became manifest within 3 months post-transplant; pre-transplant body mass index was higher (p < 0.01) in this group. Mortality did not increase. Of 123 patients in Group I who survived > 3 months, post-transplant diabetes occurred in 32% vs 16% of those with impaired and normal glucose tolerance respectively (ns), and in 55% of patients with isolated post-load hyperglycemia (p < 0.05 vs normal). Maximum random glucose values (Group II) did not predict post-transplant diabetes. Prevalence of the HLA-DR3, DR4, and DR3DR4 phenotypes did not increase in post-transplant diabetes; relation to rejection treatment was likely in 30%. Approximately 50% of posttransplant diabetes patients required only temporary drug treatment. CONCLUSIONS: The risk of post-transplant diabetes increased parallel to pre-transplant degree of glucose intolerance, but was considerable even in normal glucose tolerance. HLA-DR3 and/or DR4 phenotype was not a predisposing factor.     

Is bridging to transplantation with a left ventricular assist device a risk factor for transplant coronary artery disease?

BACKGROUND: Left ventricular assist device (LVAD) support is associated with coagulopathy, bleeding, increased blood transfusion, and increased anti-HLA antibody production. Increased anti-HLA antibody production is associated with early transplant rejection, transplant coronary artery disease (CAD), and decreased post-transplant survival rates. We asked whether bridging to transplantation with an LVAD increases the risk of transplant CAD. METHODS: We reviewed data for all adults (>18 years old) who underwent heart transplantation at our institution between 1988 and 2000. After exclusion of transplant recipients who survived <3 years, we divided the remaining cohort into 2 groups: those bridged to transplantation with LVADs (mean duration of support, 149 +/- 107 days, n = 29) and those in United Network for Organ Sharing Status 1 bridged to transplantation without LVADs (controls, n = 86). We compared groups in terms of disease cause, age, sex, donor age, panel-reactive antibody testing, crossmatching, pre- and post-transplant cholesterol concentrations, diagnosis of diabetes mellitus or treated hypertension, infections, calcium channel blocker use, transplant rejection, ischemic time, cytomegalovirus infection, pre-transplant transfusion, and incidence of transplant CAD (defined as any coronary lesion identified by coronary angiography). We considered p < 0.05 to be significant. RESULTS: The bridged and control groups were similar in all respects except mean ischemic time (217 +/- 58 minutes vs 179 +/- 67 minutes, p = 0.007), post-transplant cholesterol concentration (212 +/- 55 mg/dl vs 171 +/- 66 mg/dl, p = 0.007), and pre-transplant transfusion incidence (100% vs 22%, p < 0.001). The incidence of transplant CAD was similar in both groups during a 3-year follow-up period (28% vs 17%, p = 0.238) and during total follow-up (34% vs 35%, p = 0.969). Multivariate logistic regression analysis identified cholesterol concentration at 1 year after transplantation as a significant predictor of CAD at 3 years after heart transplantation (p = 0.0029, odds ratio = 0.984). CONCLUSIONS: Bridging to transplantation with an LVAD does not increase the risk of transplant CAD. Nevertheless, aggressive prophylactic therapy to minimize potential risk factors for transplant CAD, such as increased cholesterol concentration, is warranted in all transplant recipients.     

Renal transplant outcome in high-cardiovascular risk recipients

BACKGROUND: Cardiovascular (CV) disease is the foremost cause of mortality and an important cause of morbidity in renal transplant recipients. The disease burden is likely to increase as older patients are accepted for transplantation. The outcome of these high-CV risk patients after renal transplantation, especially with known pre-transplant coronary artery disease (CAD), has not been studied. Hence, we looked at the CV outcome in patients with known pre-transplant CAD. METHODS: All renal transplants performed between 1998 and 2002 at our center, followed up to 2005, were divided into high- and low-risk groups, based on the presence of one or more of the following: pre-transplant angina, myocardial infarction, and positive coronary angiogram. The two groups were compared for post-transplant cardiac events and patient and graft survival. The factors predictive of post-transplant cardiac events were also determined by Cox-regression multivariate analysis. RESULTS: Forty-five patients (10.5%), out of 429, had post-transplant cardiac events; 31.3% in the high risk, and 6.5% in the low-risk group (p = 0.001). Five-yr patient survival was lower in the high-risk group (82.8% vs. 93.1%, p = 0.004), while five-yr overall graft survival and death censored graft survival were statistically not different (74.8% vs. 84.1%, p = 0.08 and 87.3% vs. 90%, p = 0.25). Forty-one percent of patients who were treated with angioplasty plus stenting or bypass graft prior to transplantation had post-transplant cardiac events, as compared with 28% of those without intervention in the high-risk group and 6.5% of patients in the low-risk group (p = 0.001). Age, pre-transplant cardiac disease, arrhythmias, and low-ejection fraction (< or = 40%) were significant independent predictors of post-transplant cardiac events. CONCLUSION: Post-transplant survival of high-CV risk patients (with known CAD) is lower than that of low-risk recipients but remains acceptable. Cardiac interventions may reduce perioperative risk but do not reduce the probability of post-transplant cardiac events to that of low-risk group.     

Exercise assessment in infants after cardiac transplantation

BACKGROUND: Few data describe exercise performance after cardiac transplantation during infancy. The aim of this study was to compare the cardiorespiratory response to exercise in healthy subjects with that of subjects who had undergone heart transplantation during infancy to treat hypoplastic left heart syndrome. METHODS: Subjects (24 heart transplant recipients and 25 healthy controls) exercised on a treadmill using pediatric ramp protocols. We measured heart rate (HR), blood pressure, and metabolic data. Median age at transplantation was 20 days (range, 4 to 97 days). Age of recipients at exercise testing was 9.7 +/- 2.3 years and in healthy subjects was 10.5 +/- 1.4 years (p=not significant [NS]). RESULTS: Exercise duration was similar in both groups (10.3 +/- 2.0 minutes in recipients vs 11.1 +/- 1.5 minutes in healthy subjects, (p=NS). Heart rate at rest was greater in recipients (94 +/- 15 beats per minute [bpm] vs 85 +/- 11 bpm, p=0.02). Peak HR also was less in the recipient group (158 +/- 15 bpm vs 189 +/- 12 bpm, p <0.001). Peak oxygen consumption was 14% less in the recipients (32.3 +/- 5.6 ml/kg/min vs 36.8 +/- 5.5 ml/kg/min, p <0.01). Ventilatory anaerobic threshold was decreased in recipients, 27.6 +/- 9.6 vs 32.8 +/- 6.0, p <0.05. Respiratory exchange ratio at peak exercise was equal in both groups (1.06 +/- 0.06 vs 1.06 +/- 0.08). Oxygen pulse index did not differ significantly, 5.5 +/- 1.1 ml/beat/m2 in recipients and 6.1 +/- 1.7 ml/beat/m2 in healthy subjects (p=NS). CONCLUSIONS: Overall, children who undergo cardiac transplantation in infancy have exercise capacities within the normal range. These recipients have a decreased heart rate reserve that may account for the differences in peak oxygen consumption when compared with healthy subjects.     

A prediction model for estimating pulmonary oxygen uptake during the 6-minute walk test in organ transplant recipients

We developed a multivariate prediction equation for estimating the highest obtainable pulmonary oxygen uptake (VO2p) during the 6-minute walk test (6-MWT) in 54 organ transplant recipients: heart/heart-double-lung (n=14), kidney/kidney-pancreas (n=16), liver (n=14), double lung (n=8), bone marrow (n=2). They were of age, 48+/-12 years. Participants performed a 6-MWT during which expired gases were collected and analyzed with a portable metabolic system interfaced with a wireless heart rate monitor. The following variables significantly contributed to the model for predicting the highest obtainable 6-MWT VO2p: 6-MWT distance (m), age (years), gender (male=0, female=1), resting heart rate, peak heart rate, weight (kg), and transplant type (kidney/kidney-pancreas=1, other=0), where: VO2p=1.253+0.022 (6-MWT distance)+0.112 (age) -3.192 (gender) -0.104 (resting heart rate)+0.127 (peak 6-MWT heart rate)-0.084 (weight)+2.116 (transplant type). The explanatory variables in our final model accounted for 78% of the variance in 6-MWT VO2p. In conclusion, the addition of an easily estimated 6-MWT VO2p will provide added clinical information of functional capacity following an exercise rehabilitation intervention or during routine follow-up for organ transplant recipients.     

Long-term bone mineral density changes and fractures in lung transplant recipients with cystic fibrosis

BackgroundLittle is known about long-term bone mineral density (BMD) changes and fractures in lung transplant recipients with cystic fibrosis (CF). We examined femur and lumbar spine (LS) BMD changes in men and women with CF up to 10 years post-transplant and documented post-transplant fracture prevalence.MethodsRetrospective study of individuals who had undergone a lung transplant (2000–2015) and had a pre-transplant and at least one BMD measurement after transplant. Vertebral fractures were assessed on chest computed tomography scans and other fractures abstracted from medical records.ResultsThe cohort consisted of 131 individuals; 53% males, median age: 28 years [interquartile range: 24–35] and 31% having pre-transplant low bone mass. Most recipients were given bisphosphonates after transplant with proportion reaching 94% at 10 years. Up to 10 years post-transplant, men experienced positive or little change in LS BMD, indicating minimal loss from pre-transplant values. In contrast, women displayed negative changes in BMD up to 5 years post-transplant before recovering pre-transplant BMD values by 10 years. Similar patterns were observed at the femur BMD where men demonstrated a lower bone loss and faster recovery towards pre-transplant values than women. After transplant, 88% of recipients maintained their pre-transplant bone status, 3% experienced an improvement, mostly progressing from low bone mass to normal status whereas 9% had a deterioration of their pre-transplant bone status. Twenty-seven recipients suffered fractures in the post-transplant period.ConclusionsThese findings underline that lung recipients with CF remain at risk of skeletal fragility despite prompt initiation of post-transplant anti-osteoporosis therapy.     

The Survival Benefit of Liver Transplantation

Demand for liver transplantation continues to exceed donor organ supply. Comparing recipient survival to that of comparable candidates without a transplant can improve understanding of transplant survival benefit. Waiting list and post-transplant mortality was studied among a cohort of 12 996 adult patients placed on the waiting list between 2001 and 2003. Time-dependent Cox regression models were fitted to determine relative mortality rates for candidates and recipients. Overall, deceased donor transplant recipients had a 79% lower mortality risk than candidates (HR = 0.21; p < 0.001). At Model for End-stage Liver Disease (MELD) 18-20, mortality risk was 38% lower (p < 0.01) among recipients compared to candidates. Survival benefit increased with increasing MELD score; at the maximum score of 40, recipient mortality risk was 96% lower than that for candidates (p < 0.001). In contrast, at lower MELD scores, recipient mortality risk during the first post-transplant year was much higher than for candidates (HR = 3.64 at MELD 6-11, HR = 2.35 at MELD 12-14; both p < 0.001). Liver transplant survival benefit at 1 year is concentrated among patients at higher risk of pre-transplant death. Futile transplants among severely ill patients are not identified under current practice. With 1 year post-transplant follow-up, patients at lower risk of pre-transplant death do not have a demonstrable survival benefit from liver transplant.     

Obesity following kidney transplantation and steroid avoidance immunosuppression

Abstract:  Obesity is an important co-morbidity within end-stage renal disease (ESRD) and renal transplant populations. Previous studies have suggested that chronic corticosteroids result in increased body weight post-transplant. With the recent adoption of steroid-sparing immunosuppressive strategies, we evaluated the effect of these strategies on body mass index (BMI) after renal transplantation. We examined 95 renal transplant recipients enrolled in National Institutes of Health clinical transplant trials over the past three yr who received either lymphocyte depletion-based steroid sparing or traditional immunosuppressive therapy that included steroids for maintenance immunosuppression. Recipients were overweight prior to transplant and no significant differences existed in pre-transplant BMI among treatment groups. Regardless of therapy, BMI increased post-transplant in all recipients. The BMI increase consisted of an average weight gain of 5.01 ± 7.12 kg (mean, SD) post-transplant. Additionally, in a number of recipients placed on maintenance steroids, subsequent withdrawal at a mean of 100 d post-transplant had no impact on weight gain. Thus, body weight and BMI increase following kidney transplantation, even in the absence of steroids. Thus, patients gain weight after renal transplantation regardless of the treatment strategy. Steroid avoidance alone does not reduce risk factors associated with obesity in our patient population.     

Similarities in Skeletal Muscle Strength and Exercise Capacity Between Renal Transplant and Hemodialysis Patients

Exercise intolerance is common in hemodialysis (HD) and renal transplant (RTx) patients. Aim of the study was to assess to what extent exercise capacity and skeletal muscle strength of RTx patients differ from HD patients and healthy controls and to elucidate potential determinants of exercise capacity in RTx patients. Exercise capacity, muscle strength, lean body mass (LBM) and physical activity level (PAL) were measured by cycle-ergometry, isokinetic dynamometry, DEXA and Baecke Questionnaire, respectively, in 35 RTx, 16 HD and 21 controls. VO2peak and muscle strength of the RTx patients were significantly lower compared to controls (p<0.01), but not different compared to HD patients. In RTx patients, strength (p<0.001), PAL (p=0.001) and age (p=0.045) were significant predictors of VO2peak. Muscle strength was related to LBM (p=0.001) and age (p=0.001), whereas gender (p<0.001) and renal function (p=0.01) turned out to be significant predictors of LBM. No effects of corticosteroids were observed. Exercise capacity and muscle strength seem equally reduced in RTx and HD patients compared to controls. In RTx patients, muscle strength and PAL are highly related to exercise capacity. Renal function appears to be a significant predictor of LBM, and through the LBM, of muscle strength and exercise capacity.     

Pre- and post-transplant anti-myosin and anti-heat shock protein antibodies and cardiac transplant outcome.

BACKGROUND: The purpose this study was to investigate the relationship of anti-myosin and anti-heat shock protein immunoglobulin G (IgG) serum antibodies to the original heart disease of cardiac transplant recipients, and also to rejection and patient survival after cardiac transplantation. METHODS: Anti-myosin and anti-heat shock protein (anti-hsp) IgG antibodies were evaluated in pre-transplant sera from 41 adult cardiac allograft recipients and in sequential post-transplant serum samples from 11 recipients, collected at the time of routine endomyocardial biopsies during the first 6 months after transplantation. In addition, the levels of these antibodies were determined from the sera of 28 healthy blood donors. RESULTS: Higher anti-myosin antibody levels were observed in pre-transplant sera than in sera from normal controls. Moreover, patients with chronic Chagas heart disease showed higher anti-myosin levels than patients with ischemic heart disease, and also higher levels, although not statistically significant, than patients with dilated cardiomyopathy. Higher anti-hsp levels were also observed in patients compared with healthy controls, but no significant differences were detected among the different types of heart diseases. Higher pre-transplant anti-myosin, but not anti-hsp, levels were associated with lower 2-year post-transplant survival. In the post-transplant period, higher anti-myosin IgG levels were detected in sera collected during acute rejection than in sera collected during the rejection-free period, whereas anti-hsp IgG levels showed no difference between these periods. CONCLUSIONS: The present findings are of interest for post-transplant management and, in addition, suggest a pathogenic role for anti-myosin antibodies in cardiac transplant rejection, as has been proposed in experimental models of cardiac transplantation.     

Are preoperative obesity and cachexia risk factors for post heart transplant morbidity and mortality: a multi-institutional study of preoperative weight-height indices. Cardiac Transplant Research Database (CTRD) Group.

BACKGROUND: The relationship between pre-transplant body weight and post-transplant outcome has only recently been identified using a single, indirect measure of weight (percent ideal body weight [PIBW]). The literature is equivocal regarding which index is the better indicator of body weight. The purpose of this study was to determine (1) if pre-heart transplant body weight, measured by body mass index (BMI) and PIBW, is associated with post-heart transplant morbidity and mortality and (2) if patient gender, age, and etiology of heart disease affect this association. METHODS: The sample included 4,515 patients who received a heart transplant from January 1, 1990-December 31, 1995 at 38 institutions participating in the Cardiac Transplant Research Database (CTRD). Patients were divided into groups according to their BMI and PIBW. Data were described using frequencies, measures of central tendency, Pearson correlation coefficients, stratified actuarial analyses and log rank tests for comparisons, and a multivariable risk factor analysis in the hazard domain. RESULTS: For all patients (n = 4,515), being <80% or >140% of IBW before heart transplant was a risk factor for increased mortality after heart transplant. The association between pre-heart transplant PIBW and post-heart transplant survival was affected by gender, age, and etiology of heart disease. In males, a higher PIBW was a significant risk factor for death early after transplant (p = .0003). Although not significant, there was a trend for a higher PIBW being a risk factor for death in females throughout the post transplant period (p = .07). No differences in cause of death were found for PIBW and BMI. In male and female recipients <55 years, being overweight pre-heart transplant was a risk factor for infection. In patients with pre-transplant ischemic heart disease, the greatest risk for infection was found in patients who were >140% of IBW. Pre-heart transplant BMI and PIBW were not associated with acute rejection or cardiac allograft arteriopathy after transplant.CONCLUSIONS: In conclusion, being cachectic or obese preoperatively is associated with decreased survival in all patients after heart transplantation. Being obese preoperatively is associated with increased infection after heart transplant in males and females <55 years and in patients with ischemic heart disease. Of the 2 indices of body weight used in this study, percent ideal body weight appears to be the better predictor of future morbidity and mortality following heart transplantation.     

Blunted responses of doppler-derived aortic flow parameters during whole-body heavy isometric exercise in heart transplant recipients.

BACKGROUND: Relatively light isometric exercise (handgrip) in heart transplant recipients induces attenuated increments in heart rate, blood pressure, and systemic vascular resistance, but hemodynamic response to whole-body, heavy isometric exercise is unknown. The aim of our study was to investigate the influences of whole-body, heavy, isometric exercise on Doppler-derived parameters in these patients. METHODS: We investigated 18 patients, aged 54.0 +/- 2 years, 1.6 +/- 1.0 years after cardiac transplantation and 18 sedentary healthy volunteers, aged 51.8 +/- 4 years (p = not significant). Patients performed supine, isometric exercise by stretching a whole-body isometric device at 50% of maximal voluntary contraction for 3 minutes. RESULTS: Resting heart rate, blood pressure, and rate-pressure product were higher in transplanted patients when compared with the healthy volunteers (p < 0.001 for all). However, during isometric exercise, these parameters increased to a lesser extent in the transplanted compared with the healthy subjects-heart rate, 12% vs 40% (p < 0.001); mean arterial pressure, 20% vs 27% (p < 0.05); and rate-pressure product, 39% vs 85% (p < 0.001). In the healthy volunteers, peak-flow velocity, mean acceleration, flow-velocity integral, and stroke volume decreased by 30% to 40% with isometric exercise (p < 0.001 for all), whereas systemic vascular resistance increased by 36% (p < 0.001) and cardiac output did not change. In the transplanted patients, all above parameters remained unchanged. Heavy, whole-body isometric exercise was well tolerated in heart transplant recipients in this study, without hemodynamic deterioration or other complications. CONCLUSIONS: With whole-body, heavy isometric exercise, Doppler-derived aortic flow parameters demonstrate blunted responses or remain unchanged among heart transplant recipients. The observed phenomenon may have implications for studies of exercise physiology in transplant recipients.     

Peri-operative cardiac morbidity in kidney transplant recipients: incidence and risk factors

BACKGROUND: Renal transplant recipients are known to be at increased risk for developing cardiac disease. In both general and peripheral vascular surgery, pre-operative risk stratification (and intervention when indicated) has decreased the incidence of peri-operative cardiac complications. In this study, we set out to identify subsets of patients at high risk for peri-operative cardiac complications after a renal transplant. METHODS: We retrospectively reviewed the records of 2694 adult renal transplants performed at the University of Minnesota between January 1, 1985 and December 31, 1998. We determined the incidence of peri-operative (within 30 d post-transplant) cardiac complications, including myocardial infarction (MI). Risk factors for the development of these complications were determined by multivariate analysis. RESULTS: We found 163 peri-operative cardiac complications, for an overall incidence of 6.1%. Specific cardiac complications included MI (n=43, 1.6%), arrhythmia (n=74, 2.7%), angina (n=31, 1.2%), cardiac arrest (n=13, 0.5%), and congestive heart failure (n= 2, 0.1%). By multivariate analysis, significant risk factors for any cardiac complication were age> or =50 yr (relative risk (RR)=3.0, p=0.0001) and pre-transplant cardiac disease (RR=3.3, p=0.0001). Not significant were diabetes mellitus (DM), cadaver donor source, pre-transplant dialysis, a history of smoking, and hypertension. Significant risk factors for peri-operative MI were age> or =50 yr, pre-existing cardiac disease, and DM. Diabetic patients with pre-existing cardiac disease were at especially high risk for peri-operative cardiac events. CONCLUSIONS: Patients>50 yr and those with pre-existing cardiac disease, especially if diabetic, are at significantly increased risk for developing peri-operative cardiac complications after a renal transplant. Such patients require aggressive pre-operative investigations, which may include coronary angiography, to decrease the risk of post-transplant complications.     

Relationship of cardiac allograft size and pulmonary vascular resistance to long-term cardiopulmonary function.

The purpose of this study was to evaluate the long-term cardiopulmonary function of heart transplant patients who received disproportionately sized allografts for varying levels of pulmonary vascular resistance. Resting hemodynamics and oxygen uptake during exercise were recorded at 1 year after transplantation in 52 patients. No differences in resting heart rate, cardiac output, stroke volume, peak oxygen uptake during exercise, and exercise duration were found in recipients of undersized hearts (donor:recipient weight ratio [D:R] < 0.75), sized-matched hearts (D:R = 0.75 to 1.25), and oversized (D:R > 1.25) hearts. In a further analysis according to preoperative pulmonary vascular resistance, resting cardiac output (5.8 +/- 1.3 L/min) was normal, and peak exercise oxygen uptake (22.7 +/- 8.0 ml/kg/min) was mildly decreased in recipients of size-matched allografts with a pulmonary vascular resistance of less than 3 Wood units (size-matched hearts, with mild or no pulmonary vascular resistance). Of patients with moderate pulmonary hypertension (pulmonary vascular resistance > or = 3 Wood units), resting cardiac output was normal (5.1 +/- 0.6 L/min) in recipients of oversized hearts and was reduced (4.7 +/- 1.0 L/min) in recipients of sized-matched hearts (p < 0.05 versus recipients of size-matched hearts with pulmonary vascular resistance less than 3 Wood units).(ABSTRACT TRUNCATED AT 250 WORDS)     

Skeletal muscle limits the exercise tolerance of renal transplant recipients: effects of a graded exercise training program

Sixteen renal transplant recipients were studied before and after they had participated in a 24-week exercise training program to determine (1) the nature of the factors explaining their impaired exercise tolerance, and (2) their adaptative responses to exercise training. During progressive treadmill exercise to exhaustion prior to training, renal transplant recipients stopped exercising at lower peak rates of oxygen consumption (VO2max) (29.0 +/- 7.8 47.9 +/- 9.1 mL O2.kg-1.min-1; P less than 0.001) and ventilation (55.9 +/- 13.2 v 124.0 +/- 22.2 L.min-1; P less than 0.0001), and at lower peak heart rates (169 +/- 22 v 196 +/- 9 beats.min-1; P less than 0.05) and peak blood lactate concentrations (5.0 +/- 2.1 v 11.5 +/- 4.0 mmol.L-1; P less than 0.001) than did controls. None showed a plateau in oxygen consumption with increasing workload. Exercise time to exhaustion was also significantly shorter in renal transplant recipients (9.5 +/- 1.8 v 16.0 +/- 1.3 min; P less than 0.0001). After training, exercise time to exhaustion (12.0 +/- 2.0 min; P less than 0.001), VO2max (37.5 +/- 4.8 mL O2.kg-1.min-1; P less than 0.05), maximum ventilation rate (68.5 +/- 14.0 L.min-1; P less than 0.05), peak blood lactate concentrations (7.8 +/- 1.8 mmol-L-1; P less than 0.001), and the rate of oxygen consumption at a blood lactate concentration of 2.0 mmol.L-1 (22.5 +/- 2.5 v 16.5 +/- 2.2 mL O2.kg-1.min-1; P less than 0.001) had all increased significantly.(ABSTRACT TRUNCATED AT 250 WORDS)     

Chest size matching in single and double lung transplantation.

We applied predicted vital capacity to chest size matching between donor and recipient in lung transplantation to 15 single-lung transplant recipients with pulmonary fibrosis and to 20 double-lung transplant recipients with emphysema or non-emphysema. The predicted vital capacity of the donor was significantly correlated with the predicted vital capacity of the recipient both in double-lung transplantation (r = 0.79, p = 0.001) and single-lung transplantation (r = 0.71, p = 0.003). In double-lung transplantation, the post-transplant vital capacity was correlated with the predicted vital capacity of the recipient (r = 0.74, p = 0.002). Emphysema patients and non-emphysema patients contributed equally to this correlation. In left single lung transplantation, there was a weak correlation between the post-transplant vital capacity and the predicted vital capacity of the donor in the allograft (r = 0.57, p = 0.1095). In right single lung transplantation, the post-transplant vital capacity of the allograft tended to be correlated with the predicted vital capacity of recipient (r = 0.77, p = 0.0735). We concluded that donors were actually selected based on the comparison of predicted vital capacity between donor and recipient. In double-lung transplantation, the post-transplant vital capacity was limited by the recipient's normal thoracic volume and was not influenced by underlying pulmonary disease. In single-lung transplantation with pulmonary fibrosis, the allograft transplanted in the left chest could expand to its own size, and the allograft transplanted in the right chest could expand to the recipient's normal thoracic volume as in double-lung transplantation.     

Chest size matching in single and double lung transplantation

We applied predicted vital capacity to chest size matching between donor and recipient in lung transplantation to 15 single-lung transplant recipients with pulmonary fibrosis and to 20 double-lung transplant recipients with emphysema or non-emphysema. The predicted vital capacity of the donor was significantly correlated with the predicted vital capacity of the recipient both in double-lung transplantation (r = 0.79, p = 0.001) and single-lung transplantation (r = 0.71, p = 0.003). In double-lung transplantation, the post-transplant vital capacity was correlated with the predicted vital capacity of the recipient (r = 0.74, p = 0.002). Emphysema patients and non-emphysema patients contributed equally to this correlation. In left single lung transplantation, there was a weak correlation between the post-transplant vital capacity and the predicted vital capacity of the donor in the allograft (r = 0.57, p = 0.1095). In right single lung transplantation, the post-transplant vital capacity of the allograft tended to be correlated with the predicted vital capacity of recipient (r = 0.77, p = 0.0735). We concluded that donors were actually selected based on the comparison of predicted vital capacity between donor and recipient. In double-lung transplantation, the post-transplant vital capacity was limited by the recipient’s normal thoracic volume and was not influenced by underlying pulmonary disease. In single-lung transplantation with pulmonary fibrosis, the allograft transplanted in the left chest could expand to its own size, and the allograft transplanted in the right chest could expand to the recipient’s normal thoracic volume as in double-lung transplantation.     

Rapid Resolution of Proteinuria of Native Kidney Origin Following Live Donor Renal Transplantation

To assess the contribution of the protein content of urine from the native kidneys to post-transplant proteinuria, we prospectively studied 14 live donor transplant recipients with a pre-transplant random urine protein to creatinine ratio (UPr:Cr) >0.5. Seven patients received preemptive transplants, and seven patients were on dialysis pre-transplant (with residual urine output). Resolution of proteinuria was defined as UPr:Cr < 0.2. Immunosuppression consisted of tacrolimus, mycophenolate mofetil and corticosteroids. Anti-hypertensive drugs that might reduce proteinuria were avoided during the study. The serum creatinine was 8.7 +/- 0.7 mg/dL pre-transplant, and the nadir post-transplant serum creatinine was 1.4 +/- 0.1 mg/dL. The pre-transplant UPr:Cr ranged between 0.5 and 9.2 (mean = 2.9 +/- 0.6). The UPr:Cr decreased to <0.2 in all 14 patients at a mean of 4.5 weeks post-transplant (range 1-10 weeks). In conclusion, in live donor renal transplant recipients with immediate graft function, proteinuria of native kidney origin resolves in the early post-transplant period. After the immediate post-transplant period, proteinuria cannot be attributed to the native kidneys, and work up for proteinuria should focus on the allograft.