Early vs. late reverse ventricular remodeling in patients with cardiomyopathy

A Case of Significant Improvement of Heart Failure With Reduced Ejection Fraction With a Small Dose of Candesartan in a Hemodialysis Patient With Hypertensive Heart Disease and Nephrosclerosis

Hypertension induces vascular damage followed by organ damage, including heart failure in hypertensive heart disease (HHD) and nephrosclerosis (the resultant renal pathologic change from long-standing hypertension affecting renal vascular supply), ultimately causing renal failure. Renin-angiotensin-aldosterone system (RAAS) inhibitors are well known as effective drugs for the treatment of hypertension and the anti-remodeling of affected organs. A 52-year-old male was evaluated. Right atrophic kidney and proteinuria were noted in his high school years; however, he had no symptoms for about 35 years. He had pollakiuria in November and oliguria and leg edema in December 2020. The edema deteriorated rapidly, and general fatigue and orthopnea emerged in January 2021. Anasarca, hypertension (198/151 mmHg), tachycardia (115/minute), and hypoxemia (oxygen saturation {SpO2} of 93%) were observed on admission. A bilateral pleural effusion and pulmonary congestion were found on a chest X-ray (CXR) examination. An echocardiogram showed a 22% left ventricle ejection fraction (LVEF). Blood urea nitrogen (BUN) and serum creatinine concentrations were 70 mg/dL and 6.05 mg/dL, respectively. He was diagnosed with nephrosclerosis and HHD-induced cardiac exhaustion. Hemodialysis was started in April 2021. Even though the dry weight was decreased by draining water, cardiomegaly (cardiothoracic ratio {CTR}: 60%), low LVEF (20%-30%), and hypertension, especially diastolic hypertension (140-150/100-120 mmHg), were sustained. After 2 mg of candesartan was added in November 2021, the cardiomegaly, blood pressure (BP), and LVEF were rapidly ameliorated. The CTR and LVEF recovered to 48.5% and 60%, respectively, in April 2022. Statistical analyses showed that the independent factors for CTR were the mean monthly diastolic BP (standard partial regression coefficient {[Formula: see text]}: 0.9058, p<0.0001) and candesartan ([Formula: see text]: -0.7389, p=0.0011) in vital signs and prescribed drugs, respectively. We experienced a case of a significant effect of candesartan treatment against heart failure with reduced ejection fraction (HFrEF) caused by HHD in a hemodialysis patient with nephrosclerosis. Statistical analyses suggested that the improvement of HFrEF resistant to fluid removal by hemodialysis was presumably due to a decrease in diastolic BP caused by a small dose of candesartan.

Cardiac mitofusin-1 is reduced in non-responding patients with idiopathic dilated cardiomyopathy

Prognosis of severe heart failure remains poor. Urgent new therapies are required. Some heart failure patients do not respond to established multidisciplinary treatment and are classified as “non-responders”. The outcome is especially poor for non-responders, and underlying mechanisms are largely unknown. Mitofusin-1 (Mfn1), a mitochondrial fusion protein, is significantly reduced in non-responding patients. This study aimed to elucidate the role of Mfn1 in the failing heart. Twenty-two idiopathic dilated cardiomyopathy (IDCM) patients who underwent endomyocardial biopsy of intraventricular septum were included. Of the 22 patients, 8 were non-responders (left ventricular (LV) ejection fraction (LVEF) of < 10% improvement at late phase follow-up). Electron microscopy (EM), quantitative PCR, and immunofluorescence studies were performed to explore the biological processes and molecules involved in failure to respond. Studies in cardiac specific Mfn1 knockout mice (c-Mfn1 KO), and in vitro studies with neonatal rat ventricular myocytes (NRVMs) were also conducted. A significant reduction in mitochondrial size in cardiomyocytes, and Mfn1, was observed in non-responders. A LV pressure overload with thoracic aortic constriction (TAC) c-Mfn1 KO mouse model was generated. Systolic function was reduced in c-Mfn1 KO mice, while mitochondria alteration in TAC c-Mfn1 KO mice increased. In vitro studies in NRVMs indicated negative regulation of Mfn1 by the β-AR/cAMP/PKA/miR-140-5p pathway resulting in significant reduction in mitochondrial respiration of NRVMs. The level of miR140-5p was increased in cardiac tissues of non-responders. Mfn1 is a biomarker of heart failure in non-responders. Therapies targeting mitochondrial dynamics and homeostasis are next generation therapy for non-responding heart failure patients.

Predictors of left ventricular reverse remodeling after percutaneous therapy for mitral regurgitation with the MitraClip system

OBJECTIVES

To investigate the predictors and clinical impact of left ventricular reverse remodeling (LVRR) after MitraClip (MC) therapy for degenerative (DMR) and functional mitral regurgitation (FMR).

BACKGROUND

MC therapy induces LVRR in patients with mitral regurgitation (MR) at high-risk for surgery. However, specific data on predictors of LVRR therapy are limited.

METHODS

This study included 164 patients treated by MC implantation with complete clinical and echocardiographic evaluation at baseline, 6 months, and 12 months. LVRR was defined as a decrease of ≥10% of the left ventricular end-diastolic diameter after 12 months and was found in 49% of the patients.

RESULTS

LVRR was associated with significantly reduced event rate 2 years after MC procedure. In the total cohort, multivariate regression analysis determined severe recurrent/residual MR after 12 months (p = .010, odds ratio [OR] = 0.26), male gender (p = .050, OR = 0.49) and left ventricular ejection fraction (LVEF) <20% (p = .046, OR = 0.24) as predictors of absence of LVRR. In the subgroup analysis according to etiology of MR, multivariate regression analysis revealed severe recurrent/residual MR after 12 months (p = .04, OR = 0.184) to inversely predict LVRR only in the DMR subgroup. In FMR, residual severe tricuspid regurgitation (TR) inversely predicts LVRR (p = .032, OR = 0.361).

CONCLUSIONS

LVRR occurs in half of the patients after MC and is associated with reduced MACCE rates at follow-up. Combined information on residual/recurrent MR, baseline LVEF and gender predict LVRR after MC procedure. While residual/recurrent MR is the independent predictor for the absence of LVRR in DMR, in FMR only severe residual TR independently predict LVRR.

Pressure overload inhibits glucocorticoid receptor transcriptional activity in cardiomyocytes and promotes pathological cardiac hypertrophy

Glucocorticoid receptor (GR) is abundantly expressed in cardiomyocytes. However, the role of GR in regulating cardiac hypertrophy and heart failure in response to pressure overload remains unclear. Cardiomyocyte-specific GR knockout (GRcKO) mice, mineralocorticoid receptor (MR) knockout (MRcKO), and GR and MR double KO (GRMRdcKO) mice were generated using the Cre-lox system. In response to pressure overload, GRcKO mice displayed worse cardiac remodeling compared to control (GR^f/f) mice, including a greater increase in heart weight to body weight ratio with a greater increase in cardiomyocytes size, a greater decline in left ventricular contractility, and higher reactivation of fetal genes. MRcKO mice showed a comparable degree of cardiac remodeling compared to control (MR^f/f) mice. The worse cardiac remodeling in pressure overloaded GRcKO mice is not due to compensatory activation of cardiomyocyte MR, since pressure overloaded GRMRdcKO mice displayed cardiac remodeling to the same extent as GRcKO mice. Pressure overload suppressed GR-target gene expression in the heart. Although plasma corticosterone levels and subcellular localization of GR (nuclear/cytoplasmic GR) were not changed, a chromatin immunoprecipitation assay revealed that GR recruitment onto the promoter of GR-target genes was significantly suppressed in response to pressure overload. Rescue of the expression of GR-target genes to the same extent as sham-operated hearts attenuated adverse cardiac remodeling in pressure-overloaded hearts. Thus, GR works as a repressor of adverse cardiac remodeling in response to pressure overload, but GR-mediated transcription is suppressed under pressure overload. Therapies that maintain GR-mediated transcription in cardiomyocytes under pressure overload can be a promising therapeutic strategy for heart failure.

High body mass index is a predictor of left ventricular reverse remodelling in heart failure with reduced ejection fraction

AIMS

Structural and functional left ventricular alterations can occur in heart failure (HF), referred to as left ventricular reverse remodelling (LVRR). This study aimed to define novel predictors of LVRR besides well-known effects of medical and device therapy.

METHODS AND RESULTS

From echographic database, we included 295 patients with both left ventricular ejection fraction (LVEF) ≤45% and indexed left ventricular end-diastolic diameter ≥33 mm/m² and who had at least two echocardiographic exams with a delay between 3 and 12 months. LVRR was defined as the combination of (i) normalization of LVEF (LVEF ≥50%) or increase in LVEF ≥10% and (ii) a decrease in indexed left ventricular end-diastolic diameter ≥10%. Clinical follow-up was also obtained. LVRR occurred in 53 (18%) patients. Patients in the LVRR group were more likely to present with de novo HF (75% vs. 42%), had lower LVEF and left ventricular end-diastolic volumes at index examination, yet a higher body mass index (BMI) than non-LVRR patients. Obesity was observed in 25% of LVRR patients vs. 14% in others. In multivariate analyses, BMI (per each 1 kg/m² increase) emerged as a predictor of LVRR: odds ratio 1.10 (95% confidence interval 1.02-1.19) after adjustment to other predictors of LVRR. During a mean follow-up of 37 months, 32% of patients had a major adverse cardiac event; de novo HF, age, and LVEF were associated with major adverse cardiac event.

CONCLUSIONS

We identified significant relationship between high BMI and LVRR. This intriguing novel finding deserves further study.