SIRT6 transcriptionally regulates fatty acid transport by suppressing PPARγ.

Pathological lipid accumulation is often associated with enhanced uptake of free fatty acids via specific transporters in cardiomyocytes. Here, we identify SIRT6 as a critical transcriptional regulator of fatty acid transporters in cardiomyocytes. We find that SIRT6 deficiency enhances the expression of fatty acid transporters, leading to enhanced fatty acid uptake and lipid accumulation. Interestingly, the haploinsufficiency of SIRT6 is sufficient to induce the expression of fatty acid transporters and cause lipid accumulation in murine hearts. Mechanistically, SIRT6 depletion enhances the occupancy of the transcription factor PPARγ on the promoters of critical fatty acid transporters without modulating the acetylation of histone 3 at Lys 9 and Lys 56. Notably, the binding of SIRT6 to the DNA-binding domain of PPARγ is critical for regulating the expression of fatty acid transporters in cardiomyocytes. Our data suggest exploiting SIRT6 as a potential therapeutic target for protecting the heart from metabolic diseases.

Aberrant Aortopulmonary Venous Fistula: An Intraoperative Surprise.

An isolated systemic artery to pulmonary vein arteriovenous fistula is a rare clinical entity. We report a 20-year-old woman diagnosed with myxomatous mitral valve prolapse with severe mitral regurgitation and planned for mitral valve repair. An aberrant aortopulmonary venous fistula was suspected intraoperatively due to flooding of the left atrium with blood from the left inferior pulmonary vein on cardiopulmonary bypass. The mitral valve was repaired successfully. A postoperative computed tomography angiogram revealed an anomalous fistula between the descending thoracic aorta and left inferior pulmonary vein. The patient underwent successful percutaneous device closure of the fistula.

3D printing guided closure of submitral aneurysm-an interesting case.

Submitral aneurysm is a congenital outpouching of the left ventricular wall invariably occurring adjacent to the posterior leaflet of the mitral valve. It usually presents with heart failure symptoms. We report a case of a 59-year-old gentleman with a posterolateral submitral aneurysm who underwent aneurysm patch repair and mitral valve repair. Good knowledge about the interrelationship between the aneurysmal sac and mitral valve was obtained enabling proper surgical repair.

PTMC in post-MV repair status.

MV repair in the rheumatic population is feasible with acceptable long-term results.1 Incidence of mitral stenosis (MS) following mitral valve (MV) repair for severe rheumatic mitral regurgitation (MR) and usefulness of percutaneous transluminal mitral valvuloplasty (PTMC) in these patients is not described in literature. We report a case of successful PTMC in severe MS following MV repair for severe rheumatic MR.

Preliminary results of supra-hepatic intraaortic perfusion with nitroglycerin for patients with significant hepatic dysfunction.

BACKGROUND: Preoperative hepatic dysfunction is a risk factor for postoperative fulminant hepatic failure and death. We noted persistent hepatic artery vasospasm in patients dying of postoperative hepatic failure. We hypothesized that an intra-aortic vasodilator such as nitroglycerin could attenuate vasospasm and prevent hepatic failure. METHODS: Nineteen consecutive patients with significant preoperative hepatic dysfunction underwent cardiac surgery using cardiopulmonary bypass with continuous infusion of intra-aortic nitroglycerin via a catheter placed above the celiac axis. Serial hepatic artery Doppler studies were done perioperatively with and without the nitroglycerin infusion on. Hepatic artery Doppler, hepatic artery size, alterations in liver function and serum creatinine, and outcomes were noted. Survival was compared to the Euroscore and a hepatic risk score that was based on a historical cohort and reported literature. RESULTS: One patient could not be weaned off cardiopulmonary bypass. In the remaining 18 patients, reversible hepatic arterial vasospasm was noted, and this persisted at 24 hours in 12 patients and 48 hours in 7 patients. All patients had resolution of vasospasm at 72 hours. Serial paired hepatic artery diameter measurements showed a significant difference (P < .001). There was a significant reduction in mortality (5.2 %) compared to historical control and predicted mortality (logistic Euroscore 37.4%, P = .023). None of the survivors had a significant alteration in hepato-renal function. CONCLUSION: Intra-aortic nitroglycerin can attenuate hepatic arterial vasospasm induced by cardiopulmonary bypass and preserve hepatic function. This may reduce the risk associated with cardiopulmonary bypass and surgery in patients with liver dysfunction.

Recurrent chylopericardium.

A 19-year-old male presented with recurrent episodes of pericardial effusion. On evaluation, he was diagnosed to have idiopathic chylous effusion. As there was persistent pericardial collection, chemical pericardiodesis was done. Following pericardiodesis, there was no recurrence of pericardial effusion. Chemical pericardiodesis may be an effective treatment option for recurrent, idiopathic chylopericardium.

Flap valved closure of ventricular septal defects with increased pulmonary vascular resistance.

Closure of ventricular septal defect (VSD) in children with elevated pulmonary vascular resistance (PVR) is associated with significant morbidity and mortality with pulmonary hypertensive (PH) episodes being a major postoperative problem. Flap valved closure of VSD is reported to decrease morbidity and mortality. We report our experience of closure of a VSDs in patients with severe PH, using a valved patch in an effort to reduce the risk of operation. Eighteen consecutive patients with a large VSD with severe PH (mean PVR>8 Wood units) underwent flap valved closure (as described by Novick et al.) of VSD during a one-year study period. The mean age at surgery was 8.3±3.9 years (range: 3-13 years). Mean PVRI was 13.02±4.05 Wood units. In-hospital 30-day mortality was 5.6% (1/18). Mechanical ventilation time averaged 11.6±8.1 hours. Postoperative pulmonary artery pressures were significantly reduced. Four patients had PH crisis postoperatively. Obvious opening and closing of the flap valve was detected by echocardiography in eight patients. There were no late deaths due to cardiac causes. Closure of a large VSD in patients with severe pulmonary hypertension could be performed with low morbidity and mortality when a flap valve patch was used.