Feature-tracking cardiac magnetic resonance left ventricular global longitudinal strain improves 6 months after kidney transplantation associated with reverse remodeling, not myocardial tissue characteristics

Left Ventricular Hypertrophy After Renal Transplantation: Systematic Review and Meta-analysis

Background

Left ventricular hypertrophy (LVH) in patients with end stage renal disease undergoing renal replacement is linked to an increased risk for cardiovascular diseases. Dialysis does not completely prevent or correct this abnormality, and the evidence for kidney transplantation (KT) varies. This analysis aims to explore the relationship between KT and LVH.

Methods

MEDLINE and Scopus were systematically searched in October 2023. All cross-sectional and longitudinal studies that fulfilled our inclusion criteria were included. Outcome was left ventricular mass index (LVMI) changes. We conducted a meta-analysis using a random effects model. Meta-regression was applied to examine the LVMI changes dependent on various covariates. Sensitivity analysis was used to handle outlying or influential studies and address publication bias.

Results

From 7416 records, 46 studies met the inclusion criteria with 4122 included participants in total. Longitudinal studies demonstrated an improvement of LVMI after KT -0.44 g/m2 (-0.60 to -0.28). Blood pressure was identified as a predictor of LVMI change. A younger age at the time of KT and well-controlled anemia were also associated with regression of LVH. In studies longitudinally comparing patients on dialysis and renal transplant recipients, no difference was detected -0.09 g/m2 (-0.33 to 0.16). Meta-regression using changes of systolic blood pressure as a covariate showed an association between higher blood pressure and an increase in LVMI, regardless of the modality of renal replacement treatment.

Conclusions

In conclusion, our results indicated a potential cardiovascular benefit, defined as the regression of LVH, after KT. This benefit was primarily attributed to improved blood pressure control rather than the transplantation itself.

Effect of etelcalcetide versus alfacalcidol on left ventricular function and feature-tracking cardiac magnetic resonance imaging in hemodialysis-a post-hoc analysis of a randomized, controlled trial

BACKGROUND

Calcimimetic therapy with etelcalcetide (ETEL) has been shown to attenuate the advancement of left ventricular (LV) hypertrophy in hemodialysis patients measured by cardiac magnetic resonance (CMR). The aim of the study was to evaluate whether this effect is accompanied by alterations in LV function and myocardial composition.

METHODS

This was a post-hoc analysis of a randomized-controlled trial of ETEL versus Alfacalcidol (ALFA) in 62 hemodialysis patients. LV function was assessed using LV ejection fraction (LVEF) and LV global longitudinal strain (GLS) on feature-tracking (FT) CMR. Myocardial tissue characteristics were analyzed using parametric T1 and T2 mapping.

RESULTS

Of the total study cohort (n = 62), 48 subjects completed both CMR scans with sufficient quality for FT analysis. In the one-year follow-up, LV GLS deteriorated in the ALFA group, whereas the ETEL group remained stable (LV GLS change: + 2.6 ± 4.6 versus + 0.3 ± 3.8; p = 0.045 when adjusting for randomization factors and baseline LV GLS). We did not observe a difference in the change of LVEF between the two groups (p = 0.513). The impact of ETEL treatment on LV GLS over time remained significant after additional adjustment for the change in LV mass during the study period. ETEL treatment did not significantly affect other CMR parameters. There were no changes in myocardial composition between treatment groups (T1 time change: + 15 ± 42 versus + 10 ± 50; p = 0.411; T2 time change: - 0.13 ± 2.45 versus - 0.70 ± 2.43; p = 0.652).

CONCLUSIONS

In patients undergoing hemodialysis, treatment with ETEL was protective against deterioration of LV longitudinal function, as evaluated through FT CMR, when compared to the control therapy of ALFA. This effect was not mediated by the change in LV mass. Trial registration URL: https://clinicaltrials.gov/ct2/show/NCT03182699 . Unique identifier: NCT03182699.

Cardiac Imaging Biomarkers in Chronic Kidney Disease

Uremic cardiomyopathy (UC), the peculiar cardiac remodeling secondary to the systemic effects of renal dysfunction, is characterized by left ventricular (LV) diffuse fibrosis with hypertrophy (LVH) and stiffness and the development of heart failure and increased rates of cardiovascular mortality. Several imaging modalities can be used to obtain a non-invasive assessment of UC by different imaging biomarkers, which is the focus of the present review. Echocardiography has been largely employed in recent decades, especially for the determination of LVH by 2-dimensional imaging and diastolic dysfunction by pulsed-wave and tissue Doppler, where it retains a robust prognostic value; more recent techniques include parametric assessment of cardiac deformation by speckle tracking echocardiography and the use of 3D-imaging. Cardiac magnetic resonance (CMR) imaging allows a more accurate assessment of cardiac dimensions, including the right heart, and deformation by feature-tracking imaging; however, the most evident added value of CMR remains tissue characterization. T1 mapping demonstrated diffuse fibrosis in CKD patients, increasing with the worsening of renal disease and evident even in early stages of the disease, with few, but emerging, prognostic data. Some studies using T2 mapping highlighted the presence of subtle, diffuse myocardial edema. Finally, computed tomography, though rarely used to specifically assess UC, might provide incidental findings carrying prognostic relevance, including information on cardiac and vascular calcification. In summary, non-invasive cardiovascular imaging provides a wealth of imaging biomarkers for the characterization and risk-stratification of UC; integrating results from different imaging techniques can aid a better understanding of the physiopathology of UC and improve the clinical management of patients with CKD.

Cardiac Metabolism in Heart Failure and Implications for Uremic Cardiomyopathy

Chronic kidney disease is associated with an increased risk for the development and progression of cardiovascular disorders including hypertension, dyslipidemia, and coronary artery disease. Chronic kidney disease may also affect the myocardium through complex systemic changes, resulting in structural remodeling such as hypertrophy and fibrosis, as well as impairments in both diastolic and systolic function. These cardiac changes in the setting of chronic kidney disease define a specific cardiomyopathic phenotype known as uremic cardiomyopathy. Cardiac function is tightly linked to its metabolism, and research over the past 3 decades has revealed significant metabolic remodeling in the myocardium during the development of heart failure. Because the concept of uremic cardiomyopathy has only been recognized in recent years, there are limited data on metabolism in the uremic heart. Nonetheless, recent findings suggest overlapping mechanisms with heart failure. This work reviews key features of metabolic remodeling in the failing heart in the general population and extends this to patients with chronic kidney disease. The knowledge of similarities and differences in cardiac metabolism between heart failure and uremic cardiomyopathy may help identify new targets for mechanistic and therapeutic research on uremic cardiomyopathy.

Time-dependent cardiac structural and functional changes after kidney transplantation: a multi-parametric cardiac magnetic resonance study

OBJECTIVES

To map time-dependent cardiac structural and functional change patterns after renal transplantation (KT) using cardiac magnetic resonance (CMR).

METHODS

Fifty-three patients with pre-KT and post-KT CMR exams were retrospectively analyzed. Patients were divided into three groups according to the time of post-KT CMR: group 1 (3 months post-KT, n = 16), group 2 (6 months post-KT, n = 21), and group 3 (over 9 months post-KT, n = 16). Twenty-one age- and sex-matched healthy controls (HC) were recruited for the study. CMR-derived left ventricular (LV) volumes, LV mass index (LVMi), LV ejection fraction (LVEF), global radial strain (GRS), global circumferential strain (GCS), global longitudinal strain (GLS), and native T1 value were compared. The association between the changes of CMR parameters was assessed.

RESULTS

LVMi post-KT decreased in groups 2 (p < 0.001) and 3 (p = 0.004) but both groups had higher LVMi values compared to HC (both p < 0.001). GLS post-KT was decreased in group 1 (p = 0.021), but slightly increased in group 2 (p = 0.728) and group 3 (p = 0.100) without significant difference. GLS post-KT in group 3 was not different from HC (p = 0.104). LVEF, GRS, and GCS post-KT in groups 2 and 3 significantly increased and showed no significant difference from HC. The post-KT native T1 value in all three groups significantly decreased; however, no group showed any significant difference from HC. The change of LVEF was associated with the change of GCS, GRS, and GLS.

CONCLUSIONS

Although GRS, GCS, GLS, and native T1 values reversed to normal level, LVMi remained impaired in median 14 months after KT.

KEY POINTS

• Kidney transplantation has favorable effects on cardiac structure and function. • In a median 14 months of follow-up after KT, left ventricle strain and native T1 value reversed to normal level while LV mass index (LVMi) did not. Left ventricular hypertrophy may help to explain why KT recipients are still at increased cardiovascular risk. • The reason for the decrease of native T1 value after KT may be more than myocardial fibrosis and needs to be further studied.

T1 and T2 Mapping in Uremic Cardiomyopathy: An Update

Uremic cardiomyopathy (UC) is the cardiac remodelling that occurs in patients with chronic kidney disease (CKD). It is characterised by a left ventricular (LV) hypertrophy phenotype, diastolic dysfunction and generally preserved LV ejection fraction. UC has a major role mediating the increased rate of cardiovascular events, especially heart failure related, observed in patients with CKD. Recently, the use of T1 and T2 mapping techniques on cardiac MRI has expanded the ability to characterise cardiac involvement in CKD. Native T1 mapping effectively tracks the progression of interstitial fibrosis in UC, whereas T2 mapping analysis suggests the contribution of myocardial oedema, at least in a subgroup of patients. Both T1 and T2 increased values were related to worsening clinical status, myocardial injury and B-type natriuretic peptide release. Studies investigating the prognostic relevance and histology validation of mapping techniques in CKD are awaited.

Assessments of right ventricular strain using cardiac magnetic resonance imaging following kidney transplantation

Although kidney transplantation (KT) has been shown to ameliorate adverse left ventricular (LV) remodelling associated with end stage kidney disease, its effects on the right ventricle have not been well studied. Recently, strain imaging has been shown to be a sensitive measure of early subclinical myocardial dysfunction. Using cardiac magnetic resonance imaging (MRI), we examined the effects of KT on right ventricular (RV) strain parameters. In a cohort of 81 patients (39 patients underwent KT and 42 patients remained on dialysis as control group), cardiac MRI studies were obtained at baseline and at 1 year follow-up. There were no significant differences in RV strain values between the groups at baseline. After 1 year, RV strain values did not significantly change in patients who received KT, and changes in RV strain over 1 year were not significantly different between the KT and the dialysis groups. Given the previously demonstrated improvement in LV strain post-KT, the current study suggests that RV and LV remodelling post-KT may have different mechanisms. Further studies elucidating the effects of KT on RV remodelling are needed.