surgically-induced-cardiac-volume-overload-aortic-regurgitation

Surgically Induced Cardiac Volume Overload by Aortic Regurgitation in Mouse

Aortic regurgitation (AR) is a common valvular heart disease that exerts volume overload on the heart and represents a global public health problem. ...

Tongji University

In mice, myocardial hypertrophic preconditioning (HP), which is produced by the removal of short-term transverse aortic constriction (TAC), was recently reported to render the heart resistant to hypertrophic responses induced by subsequent reconstriction (Re-TAC). However, there is no efficient noninvasive method for ensuring that the repeated aortic manipulations were successfully performed. We previously demonstrated that ultrasound biomicroscopy (UBM) is a noninvasive and effective approach for predicting TAC success. Here, we investigated the value of UBM for serial predictions of load conditions in establishing a murine HP model. C57BL/6J mice were subjected to a sham operation, TAC, or Re-TAC, and the peak flow velocity at the aortic banding site (PVb) was measured by UBM. Left ventricular end-systolic pressure (LVESP) was examined by micromanometric catheterization. The PVb was positively associated with LVESP ( = 0.8204,  < 0.001, for TAC at 3 days and  = 0.7746,  < 0.001, for Re-TAC at 4 wk). PVb and LVESP values were markedly elevated after aortic banding, became attenuated to the sham-operated level after debanding, and increased after aortic rebanding. The cardiac hypertrophic responses were examined by UBM, histology, RT-PCR, and Western blot analysis. Four weeks after the last operation, with PVb ≥ 3.5 m/s as an indicator of successful aortic constriction, Re-TAC mice showed less cardiac hypertrophy, fetal gene expression, and ERK1/2 activation than TAC mice. Therefore, we successfully established a UBM protocol for the serial assessment of aortic flow and the prediction of LVESP during repeated aortic manipulations in mice, which might be useful for noninvasive evaluations of the murine HP model. We successfully developed an ultrasound biomicroscopy protocol for the serial assessment of aortic bandings and the relevant left ventricular pressure in a murine model of cardiac hypertrophic preconditioning. The protocol may be of great importance in the successful establishment of the hypertrophic preconditioning model for further mechanistic and pharmacological studies.

Ultrasound biomicroscopy validation of a murine model of cardiac hypertrophic preconditioning: comparison with a hemodynamic assessment.

We aimed to investigate the predictors and prognosis of left ventricular thrombus (LVT) in patients admitted for post-myocardial infarction (MI) and left ventricular dysfunction after contemporary percutaneous coronary intervention (PCI).

Predictors and prognosis of left ventricular thrombus in post-myocardial infarction patients with left ventricular dysfunction after percutaneous coronary intervention.

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor inhibitor has become the standard of care to reduce thrombotic events in patients with acute coronary syndrome or after percutaneous coronary intervention (PCI). The role of routine platelet function testing (PFT) in patients treated with DAPT after PCI remains controversial and evidence of PFT-guided antiplatelet therapy for patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI is limited.

Platelet function testing guided antiplatelet therapy reduces cardiovascular events in Chinese patients with ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention: The PATROL study.

Coronary artery aneurysm (CAA) and coronary artery ectasia (CAE) may be two different types of coronary artery dilatation with unknown etiology. This study aimed to compare the differences between CAA and CAE and to investigate their pathogenesis and the necessity of antiplatelet therapy.

Difference in inflammation, atherosclerosis, and platelet activation between coronary artery aneurysm and coronary artery ectasia.

Primary percutaneous coronary intervention (PCI) has been the standard reperfusion strategy for patients with acute myocardial infarction (AMI) in the contemporary era. Meanwhile, the incidence and prognosis of left ventricular aneurysm (LVA) in AMI patients remain ambiguous. The aim of the current study is to identify the predictor and long-term prognosis of LVA in patients with acute anterior myocardial infarction.

Predictors and long-term prognosis of left ventricular aneurysm in patients with acute anterior myocardial infarction treated with primary percutaneous coronary intervention in the contemporary era.

Aortic regurgitation (AR) is a volume overload disease causing eccentric left ventricular (LV) hypertrophy and eventually heart failure. There is currently no approved drug to treat patients with AR. Endoplasmic reticulum (ER) stress and ER stress-mediated apoptosis is involved in many cardiovascular diseases, but whether they also participate in AR-induced heart failure is still elusive. In this study, we found ER stress activation in myocardial samples from patients with AR. With a unique murine model of AR which induced eccentric cardiac hypertrophy and heart failure, we also found aggravation of cardiac ER stress and apoptosis, as evidenced by a reduction of Bcl-2/Bax ratio and an increase of caspase-3 cleavage. We then examined the signaling effectors involved in ER-initiated apoptosis and found volume overload specifically activated C/EBP homologous protein (CHOP), but not caspase-12 or Jun N-terminal kinase (JNK). Interestingly, tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor, improved cardiac function, and suppressed ER stress, apoptosis, and CHOP. Furthermore, genetic knockdown of CHOP inhibited cardiac Bcl-2/Bax ratio reduction and caspase-3 activation and rescued cardiac dysfunction. In summary, our findings suggest that ER stress-CHOP signaling is involved in the development of volume overload cardiac hypertrophy induced by AR through promoting cardiomyocytes apoptosis and provide a previously unrecognized target in heart failure induced by volume overload.

Involvement of Endoplasmic Reticulum Stress-Mediated Activation of C/EBP Homologous Protein in Aortic Regurgitation-Induced Cardiac Remodeling in Mice.

 Cardiac troponin T (cTNT) has been widely used in detecting cardiac damage. Elevated cTNT level has been reported to be associated with increased mortality in multiple cardiac conditions. It is not uncommon to observe an increased level of cTNT in patients after left atrial appendage occlusion (LAAO). The objective of the study is to study the incidence, significance, and factors associated with cTNT elevation after LAAO.  We prospectively included patients who underwent LAAO from January 2019 to July 2020 in Fudan Zhongshan Hospital. Patients were divided into those with elevated cTNT after procedure and those with normal postprocedure cTNT. All individuals were followed up for 1 year. The primary outcome is major adverse cardiovascular events, which include myocardial infarction, heart failure, cardiac death, and stroke. The second outcome is periprocedure complication, including chest pain, tachycardia, cardiac tamponade, change of electrocardiograph, and atrial thrombus.  A total of 190 patients were enrolled. Of the patients, 85.3% had elevated cTNT after LAAO, while 14.7% of them did not. Exposure time, dosage of contrast, types of devices, shapes, and sizes of LAA could contribute to elevated postprocedure cTNT. We found that patients with a Watchman device were more likely to have elevated postprocedure cTNT than those with a Lambre device (89.2 vs. 76.7%,  = 0.029). LAAO shapes were associated with cTNT levels in patients with a Watchman device, while the diameter of the outer disc and LAA depth mattered for the Lambre device. There was no significant difference in the primary and second outcome between the two groups (-value: 0.619, 0.674).  LAAO was found to be commonly accompanied with cTNT elevation, which might not to be related to the complications and adverse cardiac outcomes within 1 year of follow-up. Moreover, eGFR at baseline, exposure time, dosage of contrast, types of LAAO device, and LAA morphology could contribute to cTNT elevation.

Troponin T Elevation After Percutaneous Left Atrial Appendage Occlusion.

This study sought to investigate the dynamic functional changes of coronary intermediate lesions using quantitative flow ratio (QFR) and its implication on long-term clinical outcomes. Physiology-guided percutaneous coronary intervention in patients with angiographic intermediate lesions has been associated with favorable outcomes. This study consecutively enrolled 1130 patients with deferred intermediate lesions at baseline angiography and subsequently received second-time angiography between 9 months and 2 years later from two centers in China. The functional changes of intermediate lesions at angiographic follow-up (ΔQFR) were defined as (baseline QFR-follow-up QFR)/years. The primary outcome was vessel-oriented composite endpoint (VOCE), defined as the composite of vessel-related cardiac death, vessel-related myocardial infarction (MI), and ischemia-driven target vessel revascularization (ID-TVR) at angiographic follow-up for up to 5 years. Retrospective QFR assessment was available in 820 patients (996 intermediate lesions). QFR ≤ 0.80 at second-time angiography was associated with significantly higher 5-year VOCE (41.9% vs. 13.4%, p < 0.0001). In 777 intermediate lesions with baseline QFR > 0.80, mean ΔQFR was 0.03 ± 0.07 (median: 0.006; Q1: 0; and Q3: 0.04). The optimal cutoff of ΔQFR for predicting the primary outcome was 0.03 (area under the curve [AUC]: 0.68). The cumulative event rate of VOCE in patients with ΔQFR ≥ 0.03 was significantly higher than in those with ΔQFR < 0.03 (33.8% vs. 12.2%, p < 0.0001), driven by higher vessel-related MI and ID-TVR. The ΔQFR was a useful tool for evaluating the dynamic functional change of deferred intermediate lesions, as it demonstrates good prognostic value for long-term target vessel-related adverse events.

Xingxu Wang

Department of Cardiovascular Medicine,
Shanghai East Hospital,
School of Medicine,
Department of Cardiovascular Medicine, Shanghai East Hospital, School of Medicine

Tongji University

Surgically Induced Cardiac Volume Overload by Aortic Regurgitation in Mouse

Xingxu Wang

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Cardiovascular Medicine,Shanghai East Hospital,School of Medicine,Department of Cardiovascular Medicine, Shanghai East Hospital, School of Medicine

Tongji University

Surgically Induced Cardiac Volume Overload by Aortic Regurgitation in Mouse

Department of Cardiovascular Medicine,
Shanghai East Hospital,
School of Medicine,
Department of Cardiovascular Medicine, Shanghai East Hospital, School of Medicine