Restrictive hemodynamic patterns after cardiac transplantation: relationship to histologic signs of rejection

A Predictive Model for Intracardiac Pressures in Patients Free From Rejection or Allograft Vasculopathy After Pediatric Heart Transplantation

BACKGROUND

Despite the routine use of hemodynamic assessment in pediatric heart transplant (HT) patients, expected intracardiac pressure measurements in patients free of significant complications are incompletely described. A better understanding of the range of intracardiac pressures in these HT patients is important for the clinical interpretation of these indices and consequent management of patients.

METHODS

We conducted a retrospective chart review of pediatric HT recipients who had undergone HT between January 2010 and December 2015 at Lucile Packard Children's Hospital. We analyzed intracardiac pressures measured in the first 12 mo after HT. We excluded those with rejection, graft coronary artery disease, mechanical support, or hemodialysis. We used a longitudinal general additive model with bootstrapping technique to generate age and donor-recipient size-specific curves to characterize filling pressures through 1-y post-HT.

RESULTS

Pressure measurements from the right atrium, pulmonary artery, and pulmonary capillary wedge pressure were obtained in 85 patients during a total of 829 catheterizations. All pressure measurements were elevated in the immediate post-HT period and decreased to a stable level by post-HT day 90. Pressure measurements were not affected by age group, donor-recipient size differences, or ischemic time.

CONCLUSIONS

Intracardiac pressures are elevated in the early post-HT period and decrease to levels typical of the native heart by 90 d. Age, donor-to-recipient size differences, and ischemic time do not contribute to differences in expected intracardiac pressures in the first year post-HT.

Identifying cardiac transplant rejection in children: diagnostic utility of echocardiography, right heart catheterization and endomyocardial biopsy data

BACKGROUND

There has been a continued search for alternative diagnostic techniques that do not necessitate endomyocardial biopsy for diagnosing rejection in cardiac transplant recipients. The purpose of this study is to evaluate the role of echocardiography and hemodynamic catheterization data compared with endomyocardial biopsy results, in rejection surveillance for the pediatric heart transplant recipient.

METHODS

A prospective, blinded evaluation was performed utilizing echocardiographic and standard right heart catheterization parameters to predict acute rejection episodes.

RESULTS

Forty-nine patients underwent 281 biopsies. Two groups were defined: those with Grade <2 rejection and those with grade > or =2 rejection. None of the echocardiographic variables showed significant differences between the study groups and all group data were within normal limits. Mixed venous saturation, mean right atrial pressure, right ventricular end-diastolic pressure and mean pulmonary artery pressure were found to be statistically significant between groups. Receiver-operator characteristic (ROC) curves were constructed to determine the extent to which the various parameters were clinically useful. The ROC found little clinical usefulness for all variables, including those found to be statistically significant.

CONCLUSIONS

Differences in both echocardiographic and hemodynamic data were not clinically significant between the 2 groups of patients. Although many of the catheterization-derived parameters were statistically significant, they did not permit effective discrimination between groups. This is the only clinically relevant application of such data and may explain the conflicting previous reports. It is only through analyses such as ROC that the clinical application (or lack thereof) can be appreciated in this population.

Does total orthotopic heart transplantation offer improved hemodynamics during cellular rejection events?

BACKGROUND

We hypothesized that total orthotopic heart transplantation (TOHT) improves hemodynamics during cellular rejection compared with biatrial transplantation (SOHT).

METHODS

We reviewed 1942 biopsies from 134 patients (pts) and right heart catheterization data obtained at endomyocardial biopsy. Biopsies that displayed cellular rejection grade 1B as classified according to International Society for Heart and Lung Transplantation (ISHLT) criteria were analyzed. Pts with pacemakers, atrial fibrillation, or beta-blocker therapy at the time of biopsy were excluded. Twenty-three pts after TOHT and 38 after SOHT were identified to match these criteria.

RESULTS

Demographic data and pretransplant hemodynamics were similar. TOHT pts had a higher mean cardiac index than SOHT recipients (3.3 +/- 0.8 vs 2.7 +/- 0.5 L/min/m(2); P =.002). Right atrial mean pressure was lower after TOHT (8 +/- 4 vs 11 +/- 4 mm Hg; P =.006). Pulmonary pressures, pulmonary vascular resistance, and heart rate were similar.

CONCLUSIONS

TOHT offers improved hemodynamics during cellular rejection grade 1B as evidenced by higher cardiac output and index with lower right atrial pressures. Future studies must examine the potential benefits of TOHT during more severe rejection events.

Value of Doppler echocardiography in the detection of low-grade rejections after cardiac transplantation

Modifications of the diastolic parameters pressure half-time (PHT) and isovolumic relaxation time (IVRT), recorded using cardiac Doppler echocardiography (CDE), were studied in 23 heart transplant recipients and compared to the results of 345 endomyocardial biopsies (EMB) performed on the same day. Two different protocols, analyzing respectively (1) a decrease of 20% or more in IVRT and/or PHT with respect to the mean and (2) a decrease of 20% or more in IVRT and/ or PHT with respect to its preceding value, were used to evaluate the efficiency of CDE in diagnosing mild and moderate rejections. When a mild rejection was detected by EMB, a statistically significant decrease was found in the average CDE parameter values of the patient population. However, these variations were weak and did not differ from the spontaneous variations observed in each patient in the absence of rejection. Thus, it is not surprising that the sensitivity of CDE in the detection of mild rejections was very low (45%) using the most sensitive protocol (variations of the parameters from their preceding value). We conclude that CDE alone does not seem to be sufficient to perform the noninvasive diagnosis of low-grade rejections and must be complemented by other noninvasive methods.

Tricuspid valve regurgitation attributable to endomyocardial biopsies and rejection in heart transplantation

In the present report the prevalence, severity, and risk factors of tricuspid valve regurgitation (TR) in 251 heart transplant recipients have been analyzed retrospectively. Tricuspid valve function was studied by color-flow Doppler echocardiogram and annual heart catheterization. The presence or severity of TR was graded on a scale from 0 (no TR) to 4 (severe). Additional postoperative data included rate of rejection, number of endomyocardial biopsies, incidence of transplant vasculopathy, and preoperative and postoperative hemodynamics. The incidence of grade 3 TR increases from 5% at 1 year to 50% at 4 years after transplantation. Multivariate analysis showed rate of rejection and donor heart weight to be significant risk factors. The ischemic intervals as well as the preoperative and postoperative pulmonary hemodynamics did not affect the severity or prevalence of TR. These results indicate that various factors appear to have an impact on the development of TR and that the prevalence might be lowered by a reduction of the number of biopsies performed and when possible, oversizing of donor hearts.