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

Diastolic strain imaging: a new non-invasive tool to detect subclinical myocardial dysfunction in early cardiac allograft rejection

Acute cellular rejection (ACR) remains a significant contributor to increased morbidity and mortality in heart transplant recipients. Early detection of ACR by non-invasive imaging is of potential clinical benefit. This study sought to investigate the use of non-invasive early global diastolic strain rate (GDSRe) and global longitudinal strain (GLS) in the detection of biopsy proven ACR. We retrospectively analysed 31 heart transplant patients (Mean age 52 ± 14 years) with biopsy proven ACR who underwent serial transthoracic echocardiographic examination and 2D strain analysis. Traditional echocardiographic systolic and diastolic parameters and novel systolic and diastolic strain imaging were measured during (1) early rejection free period (0R); (2) pre-rejection period (pre-1R); and (3) grade 1R acute cellular rejection (1R-ACR). GDSRe was significantly reduced (p = 0.0001) during the pre-rejection period (pre-1R) (0.74/s) when compared with 0R (0.97/s). GLS was only significantly reduced during 1R-ACR (17.7%), p = 0.001 but could not detect pre-1R (19.9%). Global diastolic strain rate at isovolumic relaxation showed no significant differences between any of the rejection periods. Traditional systolic and diastolic indices showed no significant differences. In conclusion, early global diastolic strain rate is the most sensitive parameter to detect subclinical myocardial dysfunction during early periods of pre-1R prior to biopsy confirmed 1R-ACR. GDSRe is a potential new tool for non-invasive screening of early post-transplant cardiac allograft rejection.

Diagnostic performance of echocardiography for the detection of acute cardiac allograft rejection: a systematic review and meta-analysis

Objective

Many studies have addressed the diagnostic performance of echocardiography to evaluate acute cardiac allograft rejection compared with endomyocardial biopsy. But the existence of heterogeneity limited its clinical application. Thus, we conducted a comprehensive, systematic literature review and meta-analysis for the purpose.

Methods

Studies prior to September 1, 2014 identified by Medline/PubMed, EMBASE and Cochrance were examined by two independent reviews. We conducted meta-analysis by using Meta-DiSc 1.4 software. An assessment tool of QUADAS-2 was applied to evaluate the risk of bias and applicability of the studies.

Results

Thirty studies met the inclusion criteria of meta-analysis. The four parameters of pressure half time, isovolumic relaxation time, index of myocardial performance and late diastolic mitral annular motion velocity were included in the meta-analysis, with a pooled diagnostic odds ratio of 10.43, 6.89, 15.95 and 5.68 respectively, and the area under the summary receiver operating characteristic curves value of 0.829, 0.599, 0.871 and 0.685 respectively.

Conclusion

The meta-analysis and systematic review demonstrate that no single parameter of echocardiography showed a reliable diagnostic performance for acute cardiac allograft rejection. A result of echocardiography for ACAR should be comprehensively considered by physicians in the context of clinical presentations and imaging feature.

Cumulative episodes of rejection altered myocardial sarcoplasmic reticulum Ca(2+)-ATPase and ryanodine receptor-2 mRNA expression in heart transplant recipients

The aim of the present study was to investigate the relationship between rejections and gene expression of Ca(2+)-handling proteins in heart transplant recipients. Thirty-seven heart transplant recipients underwent routine endomyocardial biopsy. Levels of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2) and ryanodine receptor-2 mRNAs in endomyocardial tissue were quantified by a real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) method. Rejections were diagnosed according to the conventional International Society for Heart and Lung Transplantation criteria. Patients were classified as follows; group AR(+) (n = 9) with rejection grade of 2 or higher versus group AR(-) (n = 28) with rejection grade of 0, 1a or 1b at the time of biopsy, and group Rec-AR(+) (n = 6) with a history of more than 4 episodes of treatment required rejection versus group Rec-AR(-) (n = 31) without history of recurrent rejection. The mRNA levels of the SERCA2/GAPDH ratio and ryanodine receptor-2/GAPDH ratio were not different between group AR(+) and group AR(-); however, they were reduced in group Rec-AR(+) more than in group Rec-AR(-) (0.83 +/- 0.07 versus 0.90 +/- 0.07, P = 0.034, 0.74 +/- 0.06 versus 0.84 +/- 0.10, P = 0.027, respectively). A single episode of on-going rejection would not affect myocardial Ca(2+)-handling proteins; however, cumulative rejection episodes might alter the gene expression of myocardial Ca(2+)-handling proteins in heart transplant recipients.

Usefulness and limitations of transthoracic echocardiography in heart transplantation recipients

Transthoracic echocardiography is a primary non-invasive modality for investigation of heart transplant recipients. It is a versatile tool which provides comprehensive information about cardiac structure and function. Echocardiographic examinations can be easily performed at the bedside and serially repeated without any patient's discomfort. This review highlights the usefulness of Doppler echocardiography in the assessment of left ventricular and right ventricular systolic and diastolic function, of left ventricular mass, valvular heart disease, pulmonary arterial hypertension and pericardial effusion in heart transplant recipients. The main experiences performed by either standard Doppler echocardiography and new high-tech ultrasound technologies are summarised, pointing out advantages and limitations of the described techniques in diagnosing acute allograft rejection and cardiac graft vasculopathy. Despite the sustained efforts of echocardiographic technique in predicting the biopsy state, endocardial myocardial biopsies are still regarded as the gold standard for detection of acute allograft rejection. Conversely, stress echocardiography is able to identify accurately cardiac graft vasculopathy and has a recognised prognostic in this clinical setting. A normal stress-echo justifies postponement of invasive studies. Another use of transthoracic echocardiography is the monitorisation and the visualisation of the catheter during the performance of endomyocardial biopsy. Bedside stress echocardiography is even useful to select appropriately heart donors with brain death. The ultrasound monitoring is simple and effective for monitoring a safe performance of biopsy procedures.

Echocardiography in the cardiac transplant recipient

Despite the widespread use of echocardiography in the cardiac allograft recipient, the clinical usefulness of this practice is not well defined. In this article, the authors review the spectrum of echocardiographic findings in the adult heart transplant patient. Appreciation of typical alterations from "normal" allows the transplant physician to identify clinically significant changes and to avoid unnecessary invasive procedures based on misinterpretation of these differences. Though abnormalities of systolic and diastolic function correlate with episodes of acute rejection, the primary diagnostic usefulness of echocardiography in acute rejection is guiding the endomyocardial biopsy. Additionally, echocardiography has found a role as a supplement to invasive angiography in the diagnosis of cardiac allograft vasculopathy.

Relation of left ventricular diastolic function as measured by echocardiography and pulmonary capillary wedge pressure to rejection in young patients (< or = 31 years) after heart transplantation

To investigate the association of catheter-derived and newer echocardiographically derived measures of diastolic function with rejection in heart transplant recipients, 48 transplant recipients had Doppler and Doppler tissue imaging assessment along with catheter-measured pulmonary capillary wedge pressure (PCWP) at the time of endomyocardial biopsy. Of echocardiographic measures, propagation velocity (Vp), mitral E-wave velocity (E)/Vp, and E/annular mitral E-wave velocity (Em) were significantly associated with rejection (p <0.02), and an elevated PCWP was associated with rejection (p = 0.023) but with poor sensitivity. Weak but insignificant correlations with PCWP were found for E/Vp (r = 0.28) and E/Em (r = 0.37).