Cardiac transplantation: recipient selection, donor procurement, and medical follow-up. A statement for health professionals from the Committee on Cardiac Transplantation of the Council on Clinical Cardiology, American Heart Association

Weight Matching in Infant Heart Transplantation: A National Registry Analysis

BACKGROUND

Infants account for a significant proportion of pediatric heart transplantation but also suffer from a high waitlist mortality. Donor oversizing by weight-based criteria is common practice in transplantation and is prevalent in this group. We sought to analyze the impact of oversizing on outcomes in infants.

METHODS

Infant heart transplantations reported to the United Network for Organ Sharing from January 1994 to September 2019 were retrospectively analyzed. 2384 heart transplantation recipients were divided into quintiles (Q1-Q5) on the basis of donor-to-recipient weight ratio (DRWR). Multivariate Cox regression was used to estimate the effect of DRWR. The primary end point was graft survival at 1 year.

RESULTS

The median DRWR for each quintile was 0.90 (0.37-1.04), 1.17 (1.04-1.29), 1.43 (1.29-1.57), 1.74 (1.58-1.97), and 2.28 (1.97-5.00). Pairwise comparisons showed improved survival for Q3 and Q4 over each of the bottom 2 quintiles and the top quintile. Regression analyses found that Q3 and Q4 were protective against graft failure compared with the bottom 2 quintiles. There was no difference in hazard among the top 3 quintiles. Significant covariates included primary diagnosis, ischemia time, serum bilirubin level, transplantation year, mechanical ventilation at transplantation, and extracorporeal membrane oxygenation at transplantation. Sex, female-to-male transplantation, and mechanical circulatory support at transplantation were not significant in univariate analyses.

CONCLUSIONS

Modest oversizing by DRWR (1.29-1.97) is associated with increased survival and lower risk in infant heart transplantation. Additional investigation is needed to establish best practices for size matching in this population.

Initial Intravascular Ultrasound Without a Routine Early Baseline Study in the Evaluation of Cardiac Transplant Vasculopathy has Prognostic Valve

BACKGROUND

Abnormal minimal intimal thickening (MIT) on intravascular ultrasound (IVUS) defined as difference of ≥0.5 mm between baseline and one-year post-transplantation has been shown to have prognostic value. The goal of this retrospective cohort study was to evaluate whether abnormal MIT found on routine IVUS studies in cardiac transplant patients after 6 months without an early baseline study (modified MIT or MMIT), has any prognostic value. Furthermore, we evaluated the prognostic effect of serial IVUS performed beyond one year.

METHODS

A cohort of 149 cardiac transplant patients who underwent IVUS examination > 6 months post-transplant were evaluated retrospectively. Of these 149 patients, 109 patients underwent a subsequent IVUS study approximately 1 year following the initial study. MMIT values of ≥0.5 mm without an early baseline study were correlated with major adverse cardiac event (MACE).

RESULTS

The all-cause mortality was 4.7% (5/107) in patients with MMIT of <0.5 mm vs. 14.6% (6/41) in patients with MMIT of ≥0.5 mm [hazards ratio (HR): 3.2; 95% confidence interval (CI): 1.002-12.17; p = 0.039]. The overall MACE rate was 8.4% (9/107) in patients with MMIT of <0.5 mm vs. 24.4% (10/41) in patients with MMIT of ≥0.5 mm [HR: 6.7; 95% CI: 1.30-9.42; p = 0.009]. After adjusting for age, abnormal MMIT remained a significant independent predictor of MACE (HR: 3.93; CI 1.21-12.81; p = 0.023).

CONCLUSIONS

The presence of abnormal MMIT noted on IVUS performed after 6 months post-transplantation without a routine baseline IVUS carries important prognostic value.

Evaluation of Resting Cardiac Power Output as a Prognostic Factor in Patients with Advanced Heart Failure

If the heart is represented by a hydraulic pump, cardiac power represents the hydraulic function of the heart. Cardiac pump function is frequently determined through left ventricular ejection fraction using imaging. This study aims to validate resting cardiac power output (CPO) as a predictive biomarker in patients with advanced heart failure (HF). One hundred and seventy-two patients with HF severe enough to warrant cardiac transplantation were retrospectively reviewed at a single tertiary care institution between September 2010 and July 2013. Patients were initially evaluated with simultaneous right-sided and left-sided cardiac catheter-based hemodynamic measurements, followed by longitudinal follow-up (median of 52 months) for adverse events (cardiac mortality, cardiac transplantation, or ventricular assist device placement). Median resting CPO was 0.54 W (long rank chi-square = 33.6; p < 0.0001). Decreased resting CPO (<0.54 W) predicted increased risk for adverse outcomes. Fifty cardiac deaths, 10 cardiac transplants, and 12 ventricular assist device placements were documented. The prognostic relevance of resting CPO remained significant after adjustment for age, gender, left ventricular ejection fraction, mean arterial pressure, pulmonary vascular resistance, right atrial pressure, and estimated glomerular filtration rate (HR, 3.53; 95% confidence interval, 1.66 to 6.77; p = 0.0007). In conclusion, lower resting CPO supplies independent prediction of adverse outcomes. Thus, it could be effectively used for risk stratification in patients with advanced HF.

State of the Art of Combined Heart-Lung Transplantation for Advanced Cardiac and Pulmonary Dysfunction

Over the last several decades, significant advances and improvements in care of transplant patients have resulted in markedly improved outcomes. A number of options are available for patients with advanced cardiopulmonary dysfunction requiring transplantation. There is a debate about when isolated heart or isolated lung transplantation is no longer possible or advisable and combined heart-lung transplantation is justified. Organ availability and allocation severely limit the latter option to very few well-selected patients. We review practice patterns, trends, and outcomes after triple-organ heart-lung transplant (HLTx) worldwide, as well as our own experience with heart-lung transplant in the modern era.

Matching the Market for Heart Transplantation

Heart transplantation is the most effective therapy for patients with Stage D heart failure with a median life expectancy of ≈10 to 15 years. Unfortunately, many patients die on the waiting list hoping for a chance of survival. The life boat cannot rescue everyone. Over a decade, the donor pool has remained relatively stable, whereas the number of heart transplant candidates has risen. Potential recipients often have many comorbidities and are older because the criteria for heart transplantation has few absolute contraindications. Women, Hispanics, and patients with restrictive heart disease and congenital heart disease are more likely to die while awaiting heart transplantation than men, white patients, and those with either ischemic or dilated cardiomyopathy. To better match the market, we need to (1) increase the donor pool, (2) reduce the waitlist, and (3) improve the allocation system. This review article addresses all 3 options and compares strategies in the United States to those in other countries.

The association of pretransplant HeartMate II left ventricular assist device placement and heart transplantation mortality

Previous United Network for Organ Sharing (UNOS) analysis has shown an increase in posttransplant mortality with pretransplant pulsatile-flow left ventricular assist device (LVAD). Recent studies evaluating continuous-flow LVAD demonstrated improved durability, excellent survival, and improved quality of life. This study investigates the association of preheart transplant continuous-flow LVAD placement and posttransplant mortality using the UNOS database. Heart transplant patients listed after April 2004 (N = 48,090) during the era of HeartMate (HM) II LVAD usage were investigated. Patients with UNOS 1A and 1B status with (n = 1,435) and without HMII (n = 16,379) placement before the heart transplantation were evaluated. Preliminary descriptive statistics suggested an extensive heterogeneity in patient characteristics between HMII LVAD recipients and nonrecipients. Propensity scores (1:2) were used to match HMII LVAD recipients and nonrecipients characteristics and donor characteristics. This resulted in a final sample of 2,265 patients (758 with HMII pretransplant placement and 1,507 without HMII pretransplant placement). The Kaplan-Meier curves were evaluated for the differences in postheart transplant mortality in patients with and without HMII pretransplant placement. A time-dependent Cox regression model was used to study the hazard ratios (HRs) for the association between HMII pretransplant placement and posttransplant survival. The mean age of the study group was 51.9 years old (standard deviation: 12.3). HeartMate II pretransplant placement was associated with no statistically significant difference in the risk of 30 days (HR = 1.23, 95% confidence interval [CI]: 0.79-1.95, p = 0.36) and 1 year posttransplant mortality (HR = 1.31, 95% CI: 0.85-2.01, p = 0.22) compared with non-HMII recipients. The use of HMII LVAD before heart transplantation, however, was associated with a statistically significant 64% lower risk (HR = 0.36, 95% CI: 0.16-0.77, p = 0.01) of mortality among heart transplant patients who survived beyond the first year of transplantation. Continuous-flow LVAD pretransplant placement is associated with improved long-term (>1 year) survival after heart transplantation.

MRI validated echocardiographic technique to measure total cardiac volume: a tool for donor-recipient size matching in pediatric heart transplantation

Our aim is to develop and validate an accurate method for estimating TCV using standard echocardiographic imaging that can be easily employed to aid in donor-recipient size matching in pediatric heart transplantation. Thirty patients who underwent Echo and cardiac magnetic resonance imaging (cMRI) were identified. TCV was measured on cMRI. TCV was determined echocardiographically by two methods: a volume measurement using the modified Simpson's method on a four-chamber view of the heart; and a calculated volume measurement which assumed a true-elliptical shape of the heart. These two methods where compared with the value obtained by cMRI using the concordance correlation coefficient (CCC). TCV by method 1 correlated well with cMRI (CCC = 0.98%, CI = 0.97, 0.99). TCV by method 2 had a CCC = 0.90 (CI = 0.9464, 0.9716) when compared to cMRI. Left ventricular end-diastolic volume (LVEDV) also correlated as a predictor of TCV in patients with structurally normal hearts and could be described by the equation: TCV = 6.6 (LVEDV) + 12 (R(2)  = 0.97). Echocardiographic assessment of TCV for recipients and their potential donors is a simple process and can be prospectively applied as part of donor evaluation.

Significance of postoperative acute renal failure after continuous-flow left ventricular assist device implantation

BACKGROUND

Deteriorating renal function is common in patients with advanced heart failure and is associated with poor outcomes. The relationship between renal function and left ventricular assist device (LVAD) implantation is complex and has been explored in multiple studies with contradictory results. The aim of our study is to examine the significance of postoperative renal failure after implantation of a continuous-flow LVAD and its relationship to outcomes.

METHODS

From March 2006 to July 2011, 100 patients underwent implantation of a HeartMate II (Thoratec Corp, Pleasanton, CA) or HeartWare (Heart International, Inc, Framingham, MA) LVAD at our institution. Patients were stratified based on postoperative development of acute renal failure (ARF). Variables were compared using 2-sided t tests, χ(2) tests, Cox proportional hazards models, and log-rank tests to determine whether there was a difference between the 2 groups and whether postoperative renal failure was a significant independent predictor of outcome.

RESULTS

We identified 28 patients (28%) with postoperative ARF and 72 patients (72%) without postoperative ARF. The 2 groups were similar with regard to demographics and comorbidities. The patients with ARF were more likely to be intubated preoperatively (14.3% versus 1.4%; p = 0.021) and had higher preoperative central venous pressure (CVP) (14.3 mm Hg versus 10.7 mm Hg; p = 0.015). Postoperatively patients with ARF had a longer hospital stay (32.4 versus 18.7; p = 0.05), were more likely to experience right ventricular (RV) failure (25% versus 5.6%; p = 0.01) and ventilator-dependent respiratory failure (VDRF) (28.6% versus 6.9%; p = 0.007). There was a significant difference when comparing the ARF and non-ARF groups for 30-day (17.9% versus 0%; p < 0.001), 180-day (28.6% versus 2.8%; p < 0.001), and 360-day mortality (28.6% versus 6.9%; p = 0.012).

CONCLUSIONS

Patients in whom ARF developed after LVAD implantation had a higher rate of VDRF and RV failure and a longer length of stay (LOS). Postoperative ARF was associated with higher mortality at the 30-day, 180-day, and 360-day intervals. ARF after LVAD may be an early marker of poor outcome, particularly RV failure, and may be an opportunity for early intervention and rescue.

Eprosartan in the Primary Prevention of Cardiac Allograft Vascular Disease: A Double-Blind Prospectively Randomized Study using Intravascular Ultrasound

The angiotensin blocker (ARB) eprosartan (600 mg once daily) and the calcium antagonist diltiazem (90 mg twice daily) were studied in a 24-month prospective, randomized, double-blind trial involving 53 heart transplant patients. The study compared their effects on the development of post-transplant cardiac allograft vasculopathy, a condition that frequently impairs long-term post-transplantation survival and where angiotensin blockers might be expected to play a preventive role. From baseline to month 12, the mean plaque volume increased by 7.7 mm3 for eprosartan-treated patients and by 34.4 mm3 for diltiazem-treated patients, but the eprosartan-related trend for reduced myointimal hyperplasia was not statistically significant. The trend in favour of eprosartan for secondary parameters (mean intimal index, vessel volume, lumen volume and coronary flow reserve) also failed to reach significance. The lack of effect might be due to a lower than planned sample size and observation periods due to recruitment difficulties. A larger study is required to confirm these preliminary findings.

Cardiac transplantation and survival

I don't make any claims to be an expert in managing patients after cardiac transplantation, but I do recall 2 patients which I believe make the point that times have changed since the beginning of cardiac transplantation. In 1968, a patient of mine underwent cardiac transplantation. This was the first transplantation done at Johns Hopkins, and I believe it was 99(th) in the world. This patient survived the surgery very well, left the hospital, and in 4 wk he was dead.

Preserving and evaluating hearts with ex vivo machine perfusion: an avenue to improve early graft performance and expand the donor pool

Cardiac transplantation remains the first choice for the surgical treatment of end stage heart failure. An inadequate supply of donor grafts that meet existing criteria has limited the application of this therapy to suitable candidates and increased interest in extended criteria donors. Although cold storage (CS) is a time-tested method for the preservation of hearts during the ex vivo transport interval, its disadvantages are highlighted in hearts from the extended criteria donor. In contrast, transport of high-risk hearts using hypothermic machine perfusion (MP) provides continuous support of aerobic metabolism and ongoing washout of metabolic byproducts. Perhaps more importantly, monitoring the organ's response to this intervention provides insight into the viability of a heart initially deemed as extended criteria. Obviously, ex vivo MP introduces challenges, such as ensuring homogeneous tissue perfusion and avoiding myocardial edema. Though numerous groups have experimented with this technology, the best perfusate and perfusion parameters needed to achieve optimal results remain unclear. In the present review, we outline the benefits of ex vivo MP with particular attention to how the challenges can be addressed in order to achieve the most consistent results in a large animal model of the ideal heart donor. We provide evidence that MP can be used to resuscitate and evaluate hearts from animal and human extended criteria donors, including the non-heart beating donor, which we feel is the most compelling argument for why this technology is likely to impact the donor pool.

Pre-existing Pulmonary Hypertension in Patients With End-stage Heart Failure: Impact on Clinical Outcome and Hemodynamic Follow-up After Orthotopic Heart Transplantation

BACKGROUND

The purpose of this investigation was to determine the influence of pre-existing pulmonary hypertension (PHT) on outcome and to assess the pulmonary hemodynamic changes after heart transplantation (HT).

METHODS

A total of 410 patients were studied before and after (1 month and 1 year) HT: Group 1 (n = 266) had no PHT (PVR < 3 Wood units [WU], TPG < 10 mm Hg); Group 2 (n = 112) had mild-moderate PHT (PVR 3 to 6 WU, TPG 10 to 20 mm Hg); and Group 3 (n = 32) had severe PHT (PVR > 6 WU, TPG > 20 mm Hg).

RESULTS

Mean (+/- SD) follow-up was 5.2 +/- 4.1 years, mean recipient age was 57 +/- 11, and mean donor age was 30 +/- 12 years. Baseline characteristics were similar in all groups, except donor/recipient weight ratio, which was higher in patients with PHT (p = 0.002). There was a significant (p < 0.0001) decrease in mean TPG to 11.0 within the first month and to 9.5 mm Hg after the first year. Decreases in PVR to 2.2 and 2.0 WU at 1 month and 1 year, respectively (p < 0.0001 for both) were also found. Reversibility (after vasodilation) of PHT was obtained in 85% of patients in Group 2 and in 84% in Group 3. Patients' PHT did not show a significant difference in 30-day mortality (p = 0.9) and long-term survival (p = 0.8). Patients with residual post-transplant PHT (PVR > or = 3 WU) had reduced long-term survival (p = 0.03). Multivariate analysis showed no evidence that elevated PVR was associated with death.

CONCLUSIONS

Pre-existing elevated PVR that responds to vasodilator challenge does not have a negative influence on short- and long-term survival after HT. We found that residual post-transplant PHT is associated with decreased long-term survival.

Heart Transplantation in Chile: Preliminary Report From the Gustavo Fricke Hospital in Vina del Mar

OBJECTIVE

The aim of this study was to analyze our results as the national reference center of the public health network in Chile.

PATIENTS AND METHODS

Retrospective analysis of all transplantations performed between 1998 and 2005 was done and actuarial survival estimates were calculated according to Kaplan-Meier.

RESULTS

Heart transplantations were performed in 25 patients of mean age 43 +/- 11.2 years. Eight patients (32%) were transplanted from a national priority list; all patients were under intensive care support with inotropic therapy, 4 were mechanically ventilated, and 1 required an intra-aortic counter pulsation balloon. The average time on the waiting list was 145 days in nonurgent cases and 9.4 days in urgent ones. Perioperative mortality occurred in 1 patient (4%) due to primary graft failure; 2 patients died due to infectious complications during the first year of follow-up; and 1 died due to a non-cytomegalovirus (CMV) infection at 51 months after transplantation. Two patients developed acute rejection with full recovery. The most common morbidities in the current series were hypertension (71%); hyperlipidemia (71%); renal dysfunction (24%); diabetes (10%); and vasculopathy (10%). Actuarial survival rates were 87.2% and 74.7% at 12 and 86 months, respectively. At 7 years follow-up, 20 patients were in New York Heart Association (NYHA) Class I and one Class II.

CONCLUSION

Our heart transplantation program showed comparable results in the short and midterm follow-up when compared with other international reports, confirming that heart transplantation is an excellent therapeutic option for patients with end-stage heart failure.

Outcome of Heart Transplantation in Pediatric Recipients

The purpose of this study was to review the outcome of pediatric heart recipients with uncorrectable congenital heart disease, failed corrective procedures, or intractable acquired cardiomyopathy. Between 1988 and 2005, cardiac transplantations were performed in 128 pediatric patients (59 girls and 69 boys) at the Heart-Center North-Rhine-Westphalia. Their ages varied between 1 week and 18 years (mean, 7.6 +/- 6.2 years). Underlying diseases were dilative cardiomyopathy in 93 cases and uncorrectable congenital heart disease in 35 cases. We diagnosed and observed 130 episodes of acute rejection in 85 patients (65.3% of patients had an acute rejection during the observation period); 71 patients were treated efficiently with steroid-pulse therapy. Monoclonal antibody OKT3 was administrated in 14 patients because of steroid-resistant acute donor organ rejection. Five of those 14 patients survived. The cumulative survival was 88% after 1 year and 68% after 10 years for all patients. Orthotopic heart transplantation is the ultimate treatment option for children with end-stage heart disease and shows an acceptable perioperative mortality rate as well as good long-term results.

Heart transplant and left ventricular assist device costs

BACKGROUND

With the increasing clinical success of left ventricular assist devices (LVADs), physicians need to measure device cost efficacy to determine the societal value of this technology. Today's large clinical volume allows comparison of the costs of this innovation as compared with orthotopic heart transplant (OHT).

METHODS

We evaluated hospital cost and reimbursement for patients who were discharged after LVAD implantation and returned to the hospital for OHT. To control for patient-specific variables, LVAD therapy and OHT therapy were compared in the same patient; that is, only those patients who received an LVAD were discharged, and returned for OHT were studied. Length of stay (LOS), re-admissions and outpatient services were analyzed, including their respective total actual hospital cost (TAHC) and net revenue (NR). Time periods analyzed were the same for LVAD and OHT.

RESULTS

From the LVAD population at Columbia-Presbyterian Medical Center, 36 patients were discharged following HeartMate vented electric (VE) implantation and re-admitted for OHT between December 1996 and June 2000. Mean pre-LVAD implantation LOS was 21.3 +/- 24.1 days. Post-LVAD LOS was 36.8 +/- 22.2 days vs 18.2 +/- 12.2 days post-OHT (p < 0.001). Mean length of LVAD support was 123.4 +/- 77.7 days. Overall total costs for LVADs exceeded that of OHT, whereas revenue was relatively lower. TAHC post-LVAD averaged $197,957 +/- 77,291, whereas TAHC post-OHT averaged $151,646 +/-53,909 (p = 0.005). NR averaged $144,756 +/- 96,656 post-LVAD vs $178,562 +/- 68,571 post-OHT (p = 0.09). LVAD patients had more re-admissions compared with OHT: 1.2/123 days (+/- 1.7) vs 0.3/123 days (+/- 0.6), respectively (p = 0.005). The average LOS during a re-admission was similar between the 2 groups (LVAD 5.6 days [+/- 10.6] vs OHT 9.6 days [+/- 8.2]; p = 0.18). OHT was associated with a significantly greater number of outpatient services compared with LVAD (9.7 [+/- 6.1] vs 3.0 [+/- 4.7]; p < 0.001). In contrast to OHT, revenues did not match the costs of LVAD therapy.

CONCLUSIONS

LVAD implantation is associated with longer LOS and higher cost for initial hospitalization compared with OHT. LVAD patients have higher re-admission rates compared with OHT but similar costs and LOS. OHT is associated with a greater number of outpatient services. Reimbursements for LVAD therapy are relatively low, resulting in significant lost revenue. If LVAD therapy is to become a viable alternative, improvements in both cost-effectiveness and reimbursement will be necessary.

Relationship Between Renal Function and Left Ventricular Assist Device Use

BACKGROUND

Poor renal function may affect outcomes after left ventricular assist device (LVAD) placement. Conversely, LVADs may optimize circulation and improve renal function.

METHODS

To assess the relationship between renal function and LVAD use, changes in creatinine clearances (CrCl, in mL/min) were assessed retrospectively in 220 patients who underwent LVAD placement. These patients were also divided into four groups based on CrCl quartiles (< 47, 48-68, 69-95, and > 95) and compared for outcomes post-LVAD placement.

RESULTS

Eighty-four patients died on LVAD support. Survival on LVAD was worse for patients with the worst baseline CrCl (42%, 52%, 63%, and 79% for 6 month and 26%, 34%, 47%, and 66% for 12 month survival for quartiles 1-4; both p < 0.01 for trend). Adjusting for other covariates, patients in the lowest CrCl quartile were at a higher risk of dying postimplant (odds ratio 1.95, 95% confidence interval 1.14-3.63). Paired sample analysis showed the following changes in CrCl: preoperative to week 1, 77.0 +/- 46.6 to 92.1 +/- 51.1 (p < 0.01; n = 202), week 1 to 2, 89.4 +/- 49.2 to 95.2 +/- 52.4 (p = 0.01, n = 171), week 2 to 3, 107.5 +/- 58.1 to 113.7 +/- 66.1 (p = 0.16, n = 74), and week 3 to 4, 111.1 +/- 56.6 to 110.5 +/- 56.8 (p = 0.87, n = 60). For the 60 patients with baseline CrCl less than 50, CrCl increased from 36.7 +/- 9.2 to 60.1 +/- 35.5 (p < 0.01; n = 55 pairs) from preimplant to week 1. In 37 of these patients (62%) on intraaortic balloon pump support preimplant, CrCl increased from 38.4 +/- 8.2 to 67.9 +/- 40.3 mL/minute (p < 0.01) during week 1 postimplant. Recovery of renal function to CrCl greater than 50 was associated with a trend towards better 30-day survival (84% vs 66%, p = 0.09).

CONCLUSIONS

Baseline poor renal function is associated with worse outcomes after LVAD implantation. However, renal function improves substantially and rapidly in post-LVAD survivors and is associated with improved outcomes. These data underscore the importance of careful patient selection for LVAD therapy.

Cardiac Resynchronization Therapy Delays Heart Transplantation in Patients With End-stage Heart Failure and Mechanical Dyssynchrony

BACKGROUND

Cardiac dyssynchrony is frequent in advanced heart failure, and cardiac resynchronization therapy (CRT) may offer an alternative to heart transplantation. We aimed to investigate the impact of CRT on freedom from Tx and death in transplant candidates with end-stage heart failure.

METHODS

Over a period of 2 years, 46 consecutive patients with refractory congestive heart failure due to dilated cardiomyopathy were referred for heart transplant evaluation. Patients with cardiac dyssynchrony > 107 milliseconds according to tissue Doppler imaging (TDI) or QRS duration > 150 milliseconds were treated with CRT (CRT group, n = 24), whereas patients without dyssynchrony were not treated (non-CRT group, n = 22).

RESULTS

At baseline, both groups showed similar hemodynamic and functional parameters, including ejection fraction (19 +/- 10% vs 21 +/- 12%, not statistically significant [NS]) and Vo2max (11.9 +/- 2.0 vs 12.0 +/- 1.8 ml/kg/min, NS). After a follow-up of 488 +/- 346 days, cumulative survival with freedom from transplantation and death was higher in CRT vs non-CRT patients (92% vs 39%; p < 0.001). CRT patients showed a decrease in New York Heart Association (NYHA) class from 3.2 +/- 1.1 to 2.2 +/- 0.9 (p = 0.003) and an increase in Vo2max from 11.9 +/- 2.0 to 13.1 +/- 1.8 ml/kg/min (p = 0.02), and 71% (17 of 24) of these patients were successfully removed from the waiting list.

CONCLUSIONS

In heart transplant candidates with significant dyssynchrony, CRT delays heart transplantation and improves NYHA class and exercise capacity. For these patients, CRT should be considered before heart transplantation.

Different clinical scenarios for circulatory mechanical support in acute and chronic heart failure

Chronic heart failure (HF) is a leading cause of death in developed countries. Over the last 2 decades, mechanical circulatory support (MCS) devices have steadily evolved in the clinical management of end-stage HF and have emerged as a standard of care for the treatment of acute and chronic HF refractory to conventional medical therapy. Possible indications for using MCS are acute cardiogenic shock, as a bridge to transplantation, as a bridge to recovery, and more recently, as destination therapy in dilated cardiomyopathy, of either ischemic or idiopathic etiology. We reviewed the different clinical scenarios in which we think there are currently indications to implant different kinds of MCS systems.

Cardiac Transplantation

Heart transplantation is a treatment option available to patients with end-stage heart failure who meet standardized selection criteria for transplant. Through a rigorous evaluation process, professionals set out to establish the patient's severity of heart failure, screen for comorbidities that may negatively affect survival, and assess psychosocial variables necessary for successful outcomes following transplantation. Because of a limited donor organ supply, each of these factors must be examined carefully to assure that this scarce resource is used to its greatest potential benefit.

Alternative therapies for orthotopic heart transplantation

Heart failure has reached epidemic proportions in the United States. More than 5 million patients are treated for heart failure and approximately a half a million new patients are diagnosed with this disease each year in the United States. Recent pharmacological therapies have been used for the treatment of this patient population, but heart failure remains a major source of morbidity and mortality for patients. Orthotopic heart transplantation is a viable treatment option for heart failure patients; however, cardiac transplantation is limited by the donor availability. Limited donor organ availability has led to the development of alternative therapeutic strategies, including xenotransplantation, mechanical support devices, and cell transfer/tissue engineering protocols. This review highlights the current treatment modalities and emerging strategies for the treatment of advanced heart failure.

Pre-transplant reversible pulmonary hypertension predicts higher risk for mortality after cardiac transplantation

BACKGROUND

Pre-transplant fixed pulmonary hypertension is associated with higher post-transplant mortality. In this study, we assessed the significance of pre-transplant reversible pulmonary hypertension in patients undergoing cardiac transplantation.

METHODS

Overall, we studied 182 patients with baseline normal pulmonary pressures or reversible pulmonary hypertension, defined as a decrease in pulmonary vascular resistance (PVR) to < or =2.5 Wood units (WU), who underwent cardiac transplantation. Multiple recipient and donor characteristics were assessed to identify independent predictors of mortality.

RESULTS

The average duration of follow-up was 42 +/- 28 months. Forty patients (22%) died during the follow-up period. Baseline hemodynamics for alive vs dead patients were as follows: pulmonary artery systolic (PAS) 42 +/- 15 vs 52 +/- 15 mm Hg; PA diastolic 21 +/- 9 vs 25 +/- 9 mm Hg; PA mean 28 +/- 11 vs 35 +/- 10 mm Hg; transpulmonary gradient (TPG) 9 +/- 4 vs 11 +/- 7 mm Hg (all p < 0.05); total pulmonary resistance 7.7 +/- 4.8 vs 8.8 +/- 3.2 WU (p = 0.08); and PVR 2.3 +/- 1.5 vs 2.9 +/- 1.6 WU (p = 0.06). In an unadjusted analysis, patients with PAS >50 mm Hg had a higher risk of death (odds ratio [OR] 5.96, 95% confidence interval [CI] 1.46 to 19.84 as compared with PAS < or =30 mm Hg). There was no significant difference in survival among patients with baseline PVR <2.5, 2.5 to 4.0 or >4.0 WU, but patients with TPG > or =16 had a higher risk of mortality (OR 4.93, 95% CI 1.84 to 13.17). PAS pressure was an independent predictor of mortality (OR 1.04, 95% CI 1.02 to 1.06). Recipient body mass index, history of sternotomy; and donor ischemic time were the other independent predictors of mortality.

CONCLUSION

Pre-transplant pulmonary hypertension, even when reversible to a PVR of < or =2.5 WU, is associated with a higher mortality post-transplant.

Improved outcomes of pediatric dilated cardiomyopathy with utilization of heart transplantation

OBJECTIVES

We studied the outcomes of pediatric patients diagnosed with dilated cardiomyopathy (DCM) and their relation to epidemiologic and echocardiographic variables at the time of presentation.

BACKGROUND

The outcome of pediatric DCM patients ranges from recovery to a 50% to 60% chance of death within five years of diagnosis. The impact of heart transplantation and other emerging therapies on the outcomes of pediatric DCM patients is uncertain.

METHODS

We performed a retrospective study of the outcomes in 91 pediatric patients diagnosed with DCM from 1990 to 1999. Routine therapy included use of digoxin, diuretics, angiotensin-converting enzyme inhibitors, and heart transplantation.

RESULTS

At the time of last follow-up, 11 patients (12%) had died without transplantation; 20 (22%) underwent transplantation; 27 (30%) had persistent cardiomyopathy; and 33 (36%) had recovery of left ventricular systolic function. Overall actuarial one-year survival was 90%, and five-year survival was 83%. However, actuarial freedom from "heart death" (death or transplantation) was only 70% at one year and 58% at five years. Multivariate analysis found age <1 year (hazard ratio 7.1), age >12 years (hazard ratio 4.5), and female gender (hazard ratio 3.0) to be significantly associated with a greater risk of death or transplantation and a higher left ventricular shortening fraction at presentation (hazard ratio 0.92), with a slightly decreased risk of death or transplantation.

CONCLUSIONS

Pediatric DCM patients continue to have multiple outcomes, with recovery of left ventricular systolic function occurring most frequently. Utilization of heart transplantation has led to improved survival after the diagnosis of pediatric DCM.

Evaluation of pulmonary hypertension in heart transplant candidates

Assessment of the pulmonary circulation and right ventricular function is a cornerstone in the evaluation of the patient as a potential heart transplant recipient. The importance of pulmonary hypertension is linked to outcomes in the posttransplant period. Preoperative pulmonary vascular resistance is an independent risk factor for early death after heart transplantation. Pulmonary hypertension can be classified as reversible, or irreversible if not rapidly responsive to pharmacologic maneuvers. However, in most patients, the major component is likely to reverse with vasodilators, because of the central role played by the endothelium in the control of pulmonary vascular tone. To discriminate between patients with reversible and irreversible pulmonary hypertension, provocative therapies are used, and baseline and the postprovocation hemodynamic parameters are measured. To date, there is no reliable hemodynamic threshold beyond which right ventricular failure is certain to occur, nor are there values below which right ventricular failure is always avoidable. Because of this uncertainty, it becomes clear that only through careful preoperative assessment can this life-threatening condition be recognized preoperatively and, hence, managed in the posttransplant recovery period.

Noninvasive assessment of cardiac pumping capacity during exercise predicts prognosis in patients with congestive heart failure

BACKGROUND

Prognostic parameters in patients with congestive heart failure (CHF) are important for guiding therapeutic options. Maximal oxygen uptake (O(2)max) is a widely used parameter for prognostic assessment in patients with CHF and correlates with exercise cardiac output; however, afterload is not taken into account.

METHODS

The concept of a noninvasive surrogate of cardiac power output combines exercise systolic BP (SBP), as an estimate of afterload, with O(2)max, as an estimate of exercise cardiac output neglecting preload. Thus, a variable termed exercise cardiac power (ECP) is defined as the product of O(2)max (expressed as a percent predicted value) and SBP (ECP, expressed as %mm Hg, is the product of O(2)max, expressed as percentage of predicted maximum, times systolic pressure. The prognostic value of ECP obtained during routine treadmill ergospirometry was assessed in patients referred to our heart failure clinic. Patients undergoing heart transplantation were censored at the time of transplantation.

RESULTS

One hundred fifty-four patients were followed prospectively for a mean (+/- SE) duration of 625 +/- 32 days. Thirty-two patients (21%) died. ECP was the most powerful predictor of mortality, was the combined end point of mortality or hospitalization for worsening heart failure (all p < 0.001), and was an independent predictor in multivariate analysis. An ECP of < 5,000 %mm Hg indicated a poor prognosis with a 1-year mortality rate of 37%, whereas only 2% of the patients having an ECP of > 9,000 %mm Hg died during the first year.

CONCLUSION

The integration of afterload and O(2)max improves the prognostic value of each indicator, and provides an easily available and independent predictor of mortality and morbidity in CHF patients. This integrative concept of cardiac hydraulic performance is superior to O(2)max and can be used in routine ergospirometry.

Percutaneous coronary intervention versus medical therapy for coronary allograft vasculopathy. One center's experience

BACKGROUND

Coronary allograft vasculopathy, a rapidly progressive form of atherosclerosis, remains the limiting factor in the long-term survival of heart transplant recipients. Some centers have attempted percutaneous coronary intervention to slow the disease process and thereby reduce mortality in these patients, but long-term follow-up data are scarce. We compared clinical outcomes in heart transplant recipients with coronary allograft vasculopathy who were treated either with percutaneous coronary intervention or with aggressive medical therapy alone.

METHODS

A retrospective analysis of all heart transplant recipients at our institution who underwent surveillance coronary angiography for coronary allograft vasculopathy between 1995 and 2000 was performed. Patients with coronary allograft vasculopathy were stratified according to whether they received medical therapy or percutaneous coronary intervention. Baseline demographics, results of re-vascularization procedures and outcomes were analyzed.

RESULTS

From 1995 to 2000, 301 patients underwent 602 coronary angiograms. Of the 79 patients who had angiographic evidence of coronary allograft vasculopathy, 53 were treated with aggressive medical therapy, while 26 underwent percutaneous coronary intervention in addition to aggressive medical therapy. At baseline, patients treated with aggressive medical therapy tended to be younger (54.6 +/- 13.8 years) than patients treated with percutaneous coronary intervention (62.6 +/- 7.6 years; p = 0.0079). Ejection fraction at time of diagnosis of coronary allograft vasculopathy was similar for both groups (medical therapy group, 44.4 +/- 13.4% vs percutaneous coronary intervention group, 47.2 +/- 12.7%; p = 0.38). In our cohort, heart transplant recipients with coronary allograft vasculopathy demonstrated greater mortality than heart transplant recipients without coronary allograft vasculopathy (p = 0.016). Patients who underwent percutaneous coronary intervention had a 60% re-stenosis rate at 6 months if they were treated with coronary angioplasty and an 18% re-stenosis rate if they received a coronary stent. Kaplan-Meier analysis showed no significant difference in survival in either treatment group at 1 year (80% for medical therapy group vs 95% for percutaneous coronary intervention group) or 3 years (68% for medical therapy group vs 79% for percutaneous coronary intervention group) after the angiographic diagnosis of coronary allograft vasculopathy.

CONCLUSION

In this non-randomized trial, heart transplant recipients with coronary allograft vasculopathy were less likely to survive than patients without it. In addition, we found no statistical difference in mortality in heart transplant recipients with coronary allograft vasculopathy, regardless of whether they received percutaneous coronary intervention or aggressive medical therapy alone.

Prognostic value of low-dose dobutamine echocardiography in patients with idiopathic dilated cardiomyopathy

STUDY OBJECTIVES

Dobutamine echocardiography is widely used for the evaluation of myocardial contractile reserve. The purpose of the study was to determine the prognostic value of low-dose dobutamine echocardiography in patients with idiopathic dilated cardiomyopathy (IDCM).

PATIENTS

The study group consisted of 77 consecutive patients with recently diagnosed IDCM (mean [+/- SD] age, 49 +/- 9 years; men, 82%) and left ventricular (LV) ejection fractions of < 40%.

INTERVENTIONS

Two-dimensional and Doppler echocardiographic variables were measured before and after the infusion of dobutamine at the rate of 10 microg/kg/min for 5 min.

MEASUREMENTS AND RESULTS

During a mean follow-up period of 63 +/- 7 months (range, 49 to 75 months) 30 patients (39%) died and five patients (6%) underwent successful heart transplantations. Using multivariate regression analysis, the only significant factors related to fatal outcome or the need for cardiac transplantation were the following: (1) LV end-systolic volume of > 150 mL after low-dose dobutamine infusion (odds ratio [OR], 2.2; confidence interval [CI], 1.2 to 4.1; p = 0.011); (2) no decrease of LV end-diastolic volume after dobutamine infusion (OR, 1.9; CI, 1.1 to 3.4; p = 0.031); (3) atrial fibrillation (OR, 2.7; CI, 1.4 to 5.3; p = 0.003); and (4) male gender (OR, 2.6; CI, 1.2 to 5.5; p = 0.017). A scoring system was proposed with one point assigned for each of the above-mentioned factors. The mortality rates for total scores of 0, 1, 2, 3, and 4 were 0%, 19%, 48%, 83%, and 100%, respectively.

CONCLUSION

The response of the LV to low-dose dobutamine infusion adds clinically valuable prognostic information to the evaluation of the patient with IDCM.

Brain death-related energetic failure of the donor heart becomes apparent only during storage and reperfusion: an ex vivo phosphorus-31 magnetic resonance spectroscopy study on the feline heart

BACKGROUND AND OBJECTIVE

Recently, we have shown, by using localized in vivo phosphorus-31 magnetic resonance spectroscopy (31P MRS) of the anterior left ventricular wall, that brain death (BD) is not associated with reduced myocardial energy status. In this study, we applied ex vivo 31P MRS of the entire heart to study the effects of BD on the energy status of the feline donor heart following explantation.

METHODS

We used cats (6 BD and 6 controls [C]) in a 26-hour protocol. After 2 hours of preparation, we induced BD by filling an intracranial balloon at t = 0 hour. At t = 6 hours, the hearts were arrested with St. Thomas' Hospital cardioplegic solution, explanted, and stored in the same solution at 4 degrees C in a 4.7 Tesla magnet for 17 hours. Subsequently, the hearts were reperfused in the Langendorff mode at 38 degrees C for 1 hour. The first 5-minute 31P MRS spectrum was obtained 1 hour after crossclamping the aorta; we obtained subsequent spectra every hour during storage and every 5 minutes during reperfusion. At the end, the hearts were dried and weighed. Phosphocreatine (PCr), gamma-adenosine triphosphate (gamma-ATP), inorganic phosphate (Pi), and phosphomonoesters (PME), were expressed per g dry heart weight. The intracellular pH (pH(i)) and the PCr/ATP ratio were calculated.

RESULTS

During storage, we identified a significant but similar decrease of pH(i), PCr/ATP ratio, and PCr in both groups. During reperfusion, pH(i) and PCr/ATP ratio recovered similarly in both groups, whereas the recovery of PCr in the BD group was significantly lower (p < 0.05). The Pi and PME increased in both groups during storage but to a lesser extent in the BD group (p < 0.05). This difference disappeared during reperfusion. The gamma-ATP was already significantly lower in the BD group at the onset of storage, and this remained so throughout storage and reperfusion (p < 0.05 vs C). Contractile capacity was lost in all hearts, except for 1 heart in the BD group.

CONCLUSION

Brain death-related failure of the energetic integrity of the feline donor heart becomes apparent only when using 31P MRS during ischemic preservation and subsequent reperfusion.

Exercise testing with gas exchange analysis

The value of ventilatory gas exchange techniques during exercise testing, including improved precision and a greater yield of clinically useful information, is underscored by a growing body of literature. With technological advances available in the current metabolic systems, the test can be performed with minimal inconvenience to the patient and a minimal time commitment on the part of the operator. Gas exchange techniques have many applications among patients with cardiovascular and pulmonary disease, including the assessment of therapeutic interventions, a better understanding of the pathophysiology of exercise intolerance, and evaluation of disability. Recent studies suggest that the added precision provided by this technology has important prognostic utility. A cardiopulmonary exercise test can supplement other clinical and exercise test information when precision is important, when the patient's symptoms are mixed, or when it is unclear why the patient was referred for testing.

Psychosocial and behavioral selection criteria for solid organ transplantation

An evidence-based selection process for organ transplantation may be a valuable approach to improve posttransplant outcomes. This paper reviews state-of-the-art psychosocial and behavioral selection criteria and assesses their validity in view of predicting outcomes after transplantation. Psychosocial factors addressed are psychiatric disorders, mental retardation, irreversible cognitive dysfunction, and lack of social support. Behavioral selection criteria discussed are alcoholism, smoking, drug abuse, and obesity. This review reveals that the evidence concerning these selection criteria in scarce. There is a definite need for more longitudinal research to strengthen the scientific basis of the psychosocial and behavioral dimension of transplantation.

Comparative histopathology of endomyocardial biopsies in chagasic and non-chagasic heart transplant recipients

BACKGROUND

Heart transplantation has been an option for the treatment of chagasic (C) cardiomyopathy despite difficulties concerning the control of rejection and reactivation. The parasite-host interaction under the influence of immunosuppressive therapy may affect the immunological response to the graft in a pattern different from that in non-chagasic (NC) patients. The aim of this study was to compare the major histopathological features in heart transplantation in C and NC patients.

METHODS

We studied 293 endomyocardial biopsies from two groups of heart transplanted patients, including 18 C and 15 NC. Both groups had identical surgical and clinical procedure except immunosuppressive therapy was lower in C patients. The histopathological parameters evaluated were the Quilty effect, rejection, C myocarditis reactivation, fibrosis, hypertrophy, and ischemia. In addition, lymphocytic cellular infiltration of myocarditis due to rejection or reactivation was immunophenotyped in the biopsies of both groups with rejection grades 3 to 4, in biopsies with signs of reactivation, and in fragments of the receptor heart with chronic C myocarditis. A search for Trypanosoma cruzi was performed in all biopsies in the C group in which lymphocyte immunophenotyping was done. We used immunofluorescence and confocal microscopy.

RESULTS

The Quilty effect was present in 23% of the biopsies, involving 69.7% of the patients without a significant difference between groups (p = 0.509). Rejection was frequently observed in biopsies with the Quilty effect and the effect often recurred in the same patient. Rejection grades 3 to 4 was more frequent in the C group (p = 0.023). There were 5 episodes of Chagas' disease reactivation with myocarditis in 2 cases. The mean numbers of CD8+ and CD4+ T cells, and the CD4+-to-CD8+ ratio were similar for rejection in both groups (p > 0.05), while the CD4+-to-CD8+ ratio was significantly lower in chronic C myocarditis compared to rejection in the C group (p = 0.043). There was no significant difference in ischemic damage or interstitial fibrosis in the groups but there was a higher frequency of hypertrophy in the NC group (p = 0.007).

CONCLUSIONS

The histopathological features of heart transplantation in C patients did not differ from that in NC patients in regard to the Quilty effect, development of myocardial fibrosis and ischemia. However, the higher involvement of the C group for rejection grades 3 to 4 suggested higher susceptibility to this event. The similarity of the lymphocytic cellular composition for rejection in both groups indicates that C patients respond to immunological stimulus in a similar pattern as NC patients.

Cardiac transplant vasculopathy

STUDY OBJECTIVE

Coronary allograft vasculopathy (CAV) remains the major factor limiting long-term survival after heart transplantation. The purpose of this article is to review for the nontransplant physician the concept of CAV as a disease entity after heart transplantation.

DESIGN

A MEDLINE search from 1985 to 1999 was performed. Data on cardiac transplant vasculopathy were divided into pathology, pathophysiology, presentation, diagnosis, and treatment.

RESULTS

CAV manifests as a unique and unusually aggressive form of coronary artery disease that differs from traditional atherosclerosis. It is believed to be caused by immunologic mechanisms that combine with nonimmunologic factors to cause endothelial injury, resulting in smooth muscle proliferation and intimal thickening. This intimal hyperplasia leads to coronary obstruction, which ultimately results in allograft failure. Diagnosis of CAV can be difficult because transplant recipients have denervated hearts and rarely present with chest pain. Various noninvasive screening methods have not proved reliable. Therefore, most transplant centers perform periodic coronary angiography for routine CAV surveillance. Treatment of CAV involves modification of risk factors and the use of pharmacologic agents that alter vascular physiology. Revascularization procedures continue to play a role as palliative therapy, but are limited in their effectiveness by the diffuse nature of this disease.

CONCLUSION

Cardiac transplant vasculopathy continues to play a major dilemma regarding posttransplant care. Further research is needed to develop successful preventive and therapeutic strategies that may alter the course of this disease.

Heterotopic cardiac transplantation and Batista operation

We report the case of an infant who was first seen with dilated cardiomyopathy at the age of 3 1/2 months and 2 months later, successfully underwent heterotopic cardiac transplantation in combination with partial left ventriculectomy. The benefits of combining both procedures in such a young infant particularly with regard to containment of early graft dysfunction, reduction of respiratory problems, and weight mismatch are discussed.

Early alterations of myocardial blood flow reserve in heart transplant recipients with angiographically normal coronary arteries

BACKGROUND

The evaluation of the coronary reserve provides valuable information on the status of coronary vessels. Therefore, we studied with positron emission tomography (PET) and 13N-ammonia the myocardial blood flow (MBF) reserve in heart transplant recipients free of allograft rejection and with angiographically normal coronary arteries early after heart transplantation (HTx). The MBF reserve was calculated as the ratio between MBF after dipyridamole injection and basal MBF normalized for the rate-pressure product.

METHODS

Patients were studied within 3 months (group A, n = 12) or more than 9 months (group B, n = 12) after HTx. Five patients have been studied both during the early and late period after HTx. Results were compared to those obtained in 7 normal volunteers (NL).

RESULTS

Group A recipients had a significantly lower dipyridamole MBF (in ml/min/100 gr of tissue) than that of group B recipients (142+/-34 vs 195+/-59, p<0.05). This resulted in a significant decrease in MBF reserve early after HTx (group A: 1.82+/- 0.33) and a restoration to normal values thereafter (group B: 2.52+/- 0.53 vs NL: 2.62+/-0.51, p = ns). Separate analysis of 5 patients studied twice is consistent with these results.

CONCLUSION

This study shows that in heart transplant recipients free of allograft rejection and with normal coronary angiography, MBF reserve is impaired early after HTx. Restoration within one year suggests that this abnormality does not represent an early stage of cardiac allograft vasculopathy.

Preoperative assessment and management of pediatric heart transplantation

The period of preoperative management of the pediatric cardiac transplant patient can be divided into three phases: determination of transplant feasibility, listing, and medical management. Chronic infection, irreversible elevation of pulmonary vascular resistance, and intractable disease in other organ systems may all be contraindications for transplantation. The United Network for Organ Sharing has recently changed its listing guidelines. Adolescent donors are now preferentially, to some extent, allocated to adolescent recipients. Management of pediatric patients awaiting cardiac transplantation encompasses optimization of cardiac output through the use of vasodilators and oral and intravenous inotropic agents. For those patients listed for transplantation who have single ventricle lesions, such as hypoplastic left heart syndrome, management of heart failure also includes balancing systemic and pulmonary blood flows. Mechanical support of the circulation with extracorporeal membrane oxygenation or ventricular assist devices can be used as a bridge to transplant in pediatric patients.

Anesthesia for heart or single or double lung transplantation in the adult patient

Providing an anesthetic for patients undergoing heart or a single or double lung transplantation may represent a challenge even to the most experienced anesthesiologist. Patients with end-stage cardiac dysfunction have an impaired response to beta-agonist due to receptor downregulation. These patient will have isolated left ventricular dysfunction secondary to ischemic heart disease or present with biventricular failure with or without significant pulmonary hypertension. Increasingly, more patients have undergone prior major cardiac procedures and are at risk for significant perioperative bleeding. Patients undergoing single or double lung are particularly challenging because most of these procedures are performed without the aid of cardiopulmonary bypass. The anesthesiologist must be proficient at the management of one-lung ventilation techniques and have a rational physiologic approach to the management of intraoperative hypoxemia and auto-PEEP.

Bio-energetic response of the heart to dopamine following brain death-related reduced myocardial workload: a phosphorus-31 magnetic resonance spectroscopy study in the cat

OBJECTIVE

Long-term exposure of the donor heart to high dosages of dopamine in the treatment of brain death-related hemodynamic deterioration has been shown to reduce myocardial phosphocreatine (PCr) and adenosine triphosphate (ATP) in myocardial biopsy specimens and may preclude heart donation for transplantation. Short-term exposure to the acute catecholamine release during the onset of brain death has shown an unchanged PCr/ATP ratio using in vivo phosphorus-31 magnetic resonance spectroscopy (31P MRS). In this study 31P MRS was used to evaluate in vivo myocardial energy metabolism during long-term dopamine treatment.

METHODS

Twelve cats were studied in a 4.7 Tesla magnet for 360 minutes. At t = 0 minutes, brain death was induced (n = 6). At 210 minutes, when myocardial workload in the brain-death group was reduced significantly, dopamine was infused (n = 12) at 5 microg/kg/min and its dose was consecutively doubled every 30 minutes and was withheld during the last 30 minutes of the experiment. Phosphorus-31 magnetic resonance spectra were obtained from the left ventricular wall during 5-minute time frames, and PCr/ATP ratios were calculated. The hearts were histologically examined.

RESULTS

Although significant changes in myocardial workload were observed after the induction of brain death and during support and withdrawal of dopamine in both groups, the initial PCr/ATP ratio of 2.00+/-0.12 and the contents of PCr and ATP did not vary significantly. Histologically identified sub-endocardial hemorrhage was observed in 3 of 6 of the brain-dead animals and in 1 of 6 of the control animals.

CONCLUSIONS

High dosages of dopamine in the treatment of brain death-related reduced myocardial workload do not alter PCr/ATP ratios and the contents of PCr and ATP of the potential donor heart despite histologic damage.

The use of advanced-age donor hearts adversely affects survival in pediatric heart transplantation

There is a limited supply of adequate donor hearts for cardiac transplantation. The safety of using advanced-age donor hearts has been debated in adult transplantation but has not been studied previously in pediatric recipients. In this retrospective study, survival of 79 pediatric heart transplant recipients was reviewed. Pediatric recipient groups were stratified based on donor age (group 1 donor age > 40 yr, n = 5; group 2 donor age < or = 40 yr, n = 74). Survival of 267 adolescent (ages 11-17) heart transplant recipients in the United Network for Organ Sharing (UNOS) database was also reviewed. Patients were likewise divided into two groups based on donor age (> 40 yr, n = 12; < or = 40 yr, n = 255). Survival at one yr was 20% in group 1 vs. 78% in group 2 (p < 0.005). Cause of death in all group 1 patients was graft failure secondary to acute rejection. Analysis of risk of death was only significantly attributable to the age of the donor. The increased risk attributable to advanced donor age was also supported by the UNOS data. The UNOS one and two-year Kaplan-Meier survival curves were significantly lower in adolescent patients who received donor hearts > 40 yr of age. One-year survival was 58% (older donors) vs. 85% (younger donors, p < 0.005) and two-year survival was 44% (older donors) vs. 79% (younger donors, p < 0.005). Advanced-age donor hearts should be contraindicated in pediatric transplantation with the exception of critically ill patients who may not be able to wait for a younger heart.

Postoperative management following heart transplantation

Advances in surgical techniques, postoperative care, and experience have led to improved outcome in heart transplant patients. Specifically, the use of corticosteroid-free immunosuppression has reduced the risk of infection. The use of pravastatin early after transplantation has led to a decrease in clinically severe rejection episodes, improvement in survival, and reduction in transplant coronary artery disease. Reduction in natural-killer-cell cytotoxicity in the pravastatin-treated patients suggests an adjunct immunosuppressive effect of pravastatin in those patients on CyA-based immunosuppression. Quality of life has also improved in the heart transplant recipient with cardiac rehabilitation demonstrating a beneficial role in the improvement of exercise capacity. Newer immunosuppressive agents and strategies continue to demonstrate benefit in improving survival and the quality of life of the heart transplant recipient.

[Changes in the diameter of the coronary arteries in heart transplant recipients with angiographically normal vessels during five years]

INTRODUCTION

Diffuse or focal coronary artery narrowing is a frequent complication of cardiac transplantation. Coronary enlargement has also been described although it is less known. To study the changes of the coronary arteries in transplant recipients, we have performed a quantitative study throughout 5 years.

METHODS

Serial coronary angiography was performed annually in all survivors of heart transplant. Forty four patients with visually normal coronary arteries and at least 5 years of evolution were selected for this study. Quantitative measurements of the diameter of the coronary arteries were performed in each angiogram at different levels: proximal, medium and distal left anterior descending coronary artery; proximal and distal left circumflex; proximal, medium and distal right coronary artery. Changes in diameter were compared throughout the 5 years.

RESULTS

In the entire group of patients there was a small increase in the diameter of each segment. Taking each patient separately, an enlargement of the diameter of the proximal descending coronary artery was seen in 17 cases; medium descending coronary artery in 13; distal descending coronary artery in 8; proximal left circumflex in 11; distal left circumflex in 14; proximal right coronary artery in 18; medium right coronary artery in 18 and distal right coronary artery in 15. In total, 114 of 352 coronary segments (32%) underwent dilatation. Only 6 patients failed to have dilatation of any segment.

CONCLUSIONS

Enlargement of the coronary arterial diameter was seen in 32% of segments of the main coronary arteries in heart transplant recipients with angiographically normal coronary arteries during 5 years of evolution. This could be due to intimal thickening with overcompensation by an additional vessel enlargement with net lumen gain.