The year in valvular heart disease

VGLL4 plays a critical role in heart valve development and homeostasis

Heart valve disease is a major clinical problem worldwide. Cardiac valve development and homeostasis need to be precisely controlled. Hippo signaling is essential for organ development and tissue homeostasis, while its role in valve formation and morphology maintenance remains unknown. VGLL4 is a transcription cofactor in vertebrates and we found it was mainly expressed in valve interstitial cells at the post-EMT stage and was maintained till the adult stage. Tissue specific knockout of VGLL4 in different cell lineages revealed that only loss of VGLL4 in endothelial cell lineage led to valve malformation with expanded expression of YAP targets. We further semi-knockout YAP in VGLL4 ablated hearts, and found hyper proliferation of arterial valve interstitial cells was significantly constrained. These findings suggest that VGLL4 is important for valve development and manipulation of Hippo components would be a potential therapy for preventing the progression of congenital valve disease.

VGLL4, a new member of the Hippo pathway, is intensively investigated in inhibition of tumor progression via competing with YAP to bind TEADs, but its role in cardiovascular field remains unclear. Here we generated VGLL4 knockout mouse line and VGLL4-eGFP reporter mouse line. VGLL4-eGFP reporter mouse line showed VGLL4 was mainly expressed in valve interstitial cells from post-EMT stage to adult stage. Genetic loss of function and lineage tracing data demonstrated only endothelial loss of VGLL4 led to valve malformation with up-regulation of YAP targets. Of note, semi-knockout YAP could rescue this phenotype of VGLL4 knockouts. This is the first study to show the Hippo pathway plays a critical role in valve remodeling, maturation and homeostasis. Our findings suggest that mutations in VGLL4 may underlie human congenital heart valve dysplasia.

Outcomes after aortic valve replacement for aortic valve stenosis, with or without concomitant coronary artery bypass grafting

OBJECTIVES

To assess the effects of concomitant coronary artery bypass grafting (CABG), we analyzed the outcomes after aortic valve replacement (AVR) for aortic stenosis (AS) with and without coronary artery bypass grafting (CABG) at our institution.

METHODS

Between 2002 and 2014, 605 consecutive patients underwent AVR for AS. Of these, the 275 who received isolated AVR (Group A) and the 122 who received both AVR and CABG (Group AC) patients were enrolled, after the exclusion of 8 patients who underwent reoperation and 200 who received other concomitant surgery. AVR and all bypass anastomoses were performed under intermittent retrograde cold blood cardioplegia. Multivariate analysis was used to assess any association of concomitant CABG with morbidity and mortality. Kaplan-Meier analysis was used to assess all-cause mortality.

RESULTS

No significant difference in 30-day mortality was found between Group A and Group AC (1.5% vs. 0.8%, P = 1.000). Nor did post-discharge survival differ significantly between the two groups (P = 0.20). Likewise, multivariate analysis showed that concomitant CABG was not associated with significantly greater in-hospital or mid-term mortality. Operative morbidities were comparable between the two groups, in terms of stroke (1.8% vs. 3.3%, P = 0.466), prolonged ventilation (4.0% vs. 5.5%, P = 0.565), deep sternal infection (1.8% vs. 3.3%, P = 0.466), and acute renal failure (0.4% vs. 1.6% P = 0.176).

CONCLUSIONS

Concomitant CABG at the time of AVR was performed without increasing early- or mid-term mortality. This absence of increased risk deserves consideration when choosing between different treatment strategies.

Editor-in-chief's picks from 2014: part two

As I spent countless hours pouring over hundreds of manuscripts to select those that rose to the top over the past year, I became incredibly excited about being part of a Journal that produces such wonderfully rich and diverse content each year. I have personally selected the papers (both original investigations and review articles) from 13 distinct specialties for your review. There are approximately 150 articles selected across this 2-part series, which represents less than 3% of the papers submitted to JACC in 2014. In order to present the full breadth of this important research in a consumable fashion, we will present these manuscripts over the course of 2 issues of JACC. Part One includes the sections: Congenital Heart Disease, Coronary Disease & Interventions, Genetics, Omics, & Tissue Regeneration, CV Prevention & Health Promotion, Cardiac Failure, and Cardiomyopathies. Part Two includes the sections: Hypertension, Imaging, Metabolic Disorders & Lipids, Neurovascular & Neurodegenerative Disorders, Rhythm Disorders, Valvular Heart Disease, and Vascular Medicine (1-86).