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Severe tricuspid regurgitation (TR) is life-threatening but is often undertreated. Many patients with severe TR are denied heart valve replacement surgery because their old age or comorbidities predispose them to a higher risk of surgical complications associated with open-heart surgery. With the advent of transcatheter technology, it is now possible to deliver the valve to the desired location without the need for open-heart surgery. However, presently, there is no commercially available transcatheter tricuspid valve. This may be due to the complex tricuspid valve anatomy, which lacks an anchorage zone for the percutaneous valves. In view of this drawback, we have recently developed and tested two percutaneous caval heart valves that are designed to deploy at the vena cava and atrium junction. The hemodynamic characteristics of these valves are tested in a mock circulatory system with patient-specific silicone atrium and vena cava, which emulates the physiological pressure and flow conditions at the right side of the human heart. Particle imaging velocimetry results showed that flow velocity and the associated Reynolds shear stress (RSS) and the turbulent kinetic energy (TKE) downstream of the valves increased after the implantation of the valves. A maximum flow velocity of 0.94 m/s was observed at the region downstream of the percutaneous valve at the superior vena cava (SVC). Maximum RSS value of 2076.1 dynes/cm(2) was observed downstream of the valve at the inferior vena cava during the deceleration phase while maximum TKE measured was 572.6 J/m(3) at the upstream of the valve in the SVC during the peak flow phase. While these values appear high, they are significantly lower than those reported in prosthetic mitral and aortic valves. Hence, caval stented valves can be potentially considered as a minimally invasive option to treat TR.

We report the case of a 23-year-old man who developed constrictive pericarditis within four months after pulmonary valve replacement and repair of partial anomalous pulmonary venous connection. He had previously undergone repair of tetralogy of Fallot in infancy. After an unsuccessful trial of medical management for persistent right heart failure, magnetic resonance imaging was done, which showed a thickened pericardium. He underwent a radical pericardiectomy with a good outcome. The case is presented to illustrate a less well-recognized cause of cardiac failure following congenital cardiac surgery, which may otherwise be attributed to the failure of surgery or residual complications.

Intra-ventricular flow dynamics has recently emerged as an important evaluation and diagnosis tool in different cardiovascular conditions. The formation of vortex pattern during the cardiac cycle has been suggested to play important epigenetic and energy-modulation roles in cardiac remodelling, adaptations and mal-adaptations. In this new perspective, flow alterations due to different cardiovascular procedures can affect the long-term outcome of those procedures. Especially, repairs and replacements performed on atrioventricular valves are likely to exert direct impact on intra-ventricular flow pattern. In this review, current consensus around the roles of vortex dynamics in cardiac function is discussed. An overview of physiological vortex patterns found in healthy left and right ventricles as well as post-operative ventricular flow phenomenon owing to different atrioventricular valvular procedures are reviewed, followed by the summary of different vortex identification schemes used to characterise intraventricular flow. This paper also emphasises on future research directions towards a comprehensive understanding of intra-cardiac flow and its clinical relevance. The knowledge could encourage more effective pre-operative planning and better outcomes for current clinical practices.

When Viktor Eisenmenger first described (1897) and later Paul Wood (1958) expanded on the Eisenmenger syndrome (ES), the options of treatment of this condition were very limited. The pulmonary hypertension (PH) associated with this condition was believed to be irreversible. Palliative care management and heart/heart-lung transplant were the only available treatment available. The study conducted by Arnott and colleagues have once again reminded us that there are now more effective options. Their study showed that, in a binational cohort of patients with ES followed up in expert congenital heart centres in Australia and New Zealand for a mean duration of 8.3 years, advanced therapy (mostly bosentan) was associated with a reduction in mortality.1 This study should spur us to do more for these patients. The prognosis of ES has been frequently compared with iPAH and often said to be superior for several years. However, recent studies have showed that this may not be the case due to the inherent biases present in the earlier studies.2 Mortality rates in these patients remain high with adjusted 10-year mortality rates of up to 40%. In addition, ES patients have very poor exercise tolerance and reduced quality of life. For the same degree of cyanosis, patients with ES had much poorer cardiopulmonary exercise test results than other cyanotic heart patients.3 In fact, …

The use of transcatheter aortic valve implantation (TAVI) to treat severe symptomatic aortic valve stenosis has increased exponentially in the last decade. This rapid expansion was seen predominantly in Western developed nations and has been fuelled by favorable results reported from a plethora of well-publicized randomized controlled trials, large retrospective series and national registries. Now, TAVI has become the standard of care for inoperable patients and an alternative to open surgery in patients who are at intermediate to high risk for open surgery. Notwithstanding these positive results, Asia has been relatively slow to adopt this technology despite a potentially large patient pool. Unique features of Asian medical environments and differences in Asian anatomy affecting TAVI uptake in Asia will be discussed. This article serves to outline the various challenging aspects of disseminating TAVI in Asian countries.

The concept of heterotopic implantation of transcatheter tricuspid valve is new and has shown promising results thus far. While the Reynolds shear stress values measured in the vicinity of this valve are relatively low, the values at some time points are higher than the threshold of platelet activation. Hence, in this study, we aim to reduce these values with an innovative stent design. It was shown that the Reynolds shear stress values measured were lower than those of valves made of generic stent design and the maximum Reynolds shear stress values in the vicinity of the valves was very low (∼10 dynes/cm

We report the case of a 70-year-old man with an asymptomatic large patent ductus arteriosus (PDA) incidentally detected on triple-rule-out computed tomography (CT). CT clearly demonstrated a vascular structure connecting the descending thoracic aorta to the roof of the proximal left pulmonary artery, consistent with a PDA. Secondary pulmonary arterial hypertension was also evident on CT. The patient was eventually diagnosed with acute coronary syndrome and was successfully treated with coronary artery bypass graft surgery and concomitant patch closure of the PDA. This article aims to outline the imaging features of PDA and highlight the information provided by CT, which is crucial to treatment planning. The pathophysiology, clinical manifestations and closure options of PDA are also briefly discussed.

Ischemia/reperfusion injury remains an untreated clinical problem in patients with acute myocardial infarction (AMI) despite significant advances in emergent revascularization through percutaneous coronary intervention (PCI). Pharmacological intervention for infarct size reduction is unavailable. We have identified that the medications milrinone and esmolol, when administered together at the beginning of the reperfusion, significantly decrease infarct size via reducing reperfusion injury in an experimental model. The present study tested the safety of combination therapy of milrinone and esmolol (M + E) in patients with AMI. Sixteen subjects with AMI requiring PCI were consecutively recruited. M + E was intravenously infused simultaneously for 10 min started at 5 min before anticipated angioplasty balloon inflation. Another 16 consecutively recruited AMI patients requiring PCI served as a placebo arm treated per routine clinical protocol. Blood pressure (BP) and heart rate (HR) were monitored continuously during PCI. M + E combination therapy resulted in a trend of non-significant reduction in BP compared with a control group. There was a modest but significant increase in HR at the later phase of M + E infusion compared with a control group. No significant cardiac arrhythmia was induced during M + E infusion. The combination therapy with M + E produces a minimal change in hemodynamics and appears safe as an adjunctive therapy to PCI in AMI patients. Further studies are warranted.

Background Transcatheter aortic valve replacement (TAVR) has been shown safe and feasible in patients with bicuspid aortic valve (BAV) morphology. Evaluation of inter-ethnic differences in valve morphology and function and aortic root dimensions in patients with BAV is important for the worldwide spread of this therapy in this subgroup of patients. Comparisons between large European and Asian cohorts of patients with BAV have not been performed, and potential differences between populations may have important implications for TAVR. Aim The present study evaluated the differences in valve morphology and function and aortic root dimensions between two large cohorts of European and Asian patients with BAV. Methods and results Aortic valve morphology was defined on transthoracic echocardiography according to the number of commissures and raphe: type 0 = no raphe and two commissures, type 1 = one raphe and two commissures, type 2 = two raphes and one commissure. Aortic stenosis and regurgitation were graded according to current recommendations. For this study, aortic root dimensions were manually measured on transthoracic echocardiograms at the level of the aortic annulus, sinus of Valsalva (SOV), sinotubular junction (STJ), and ascending aorta (AA). Of 1427 patients with BAV (45.2 ± 18.1 years, 71.9% men), 794 (55.6%) were Europeans and 633 (44.4%) were Asians. The groups were comparable in age and proportion of male sex. Asians had higher prevalence of type 1 BAV with raphe between right and non-coronary cusps than Europeans (19.7% vs. 13.6%, respectively; P

INTRODUCTION Transcatheter aortic valve implantation (TAVI) is an effective treatment for high-risk or inoperative patients with severe aortic stenosis. Given the unique characteristics of Asian populations, questions regarding mid-term outcomes in Asians undergoing TAVI have yet to be addressed. We evaluated the two-year clinical outcomes of TAVI in an Asian population using Valve Academic Research Consortium-2 definitions. METHODS This prospective study recruited 59 patients from a major academic medical centre in Singapore. The main outcomes were two-year survival rates, peri-procedural complications, symptom improvement, valvular function and assessment of learning curve. RESULTS Mean age was 76.8 years (61.0% male), mean body surface area 1.6 m2 and mean logistic EuroSCORE 18.7%. Survival was 93.2%, 86.0% and 79.1% at 30 days, one year and two years, respectively. At 30 days post TAVI, the rate of stroke was 1.7%, life-threatening bleeding 5.1%, acute kidney injury 25.0%, major vascular complication 5.1%, and new permanent pacemaker implantation 6.8%. 29.3% of TAVI patients were rehospitalised (47.1% cardiovascular-related) within one year. These composite outcomes were measured: device success (93.2%); early safety (79.7%); clinical efficacy (66.1%); and time-related valve safety (84.7%). Univariate analysis found these predictors of two-year all-cause mortality: logistic EuroSCORE (hazard ratio [HR] 1.07; p < 0.001); baseline estimated glomerular filtration rate (HR 0.97; p = 0.048); and acute kidney injury (HR 5.33; p = 0.022). Multivariate analysis identified non-transfemoral TAVI as a predictor of cardiovascular-related two-year mortality (HR 14.64; p = 0.008). CONCLUSION Despite the unique clinical differences in Asian populations, this registry demonstrated favourable mid-term clinical and safety outcomes in Asians undergoing TAVI.

Myxomatous mitral valve prolapse (MMVP) and fibroelastic deficiency (FED) are two common variants of degenerative mitral valve disease (DMVD), which is a leading cause of mitral regurgitation worldwide. While pathohistological studies have revealed differences in extracellular matrix content in MMVP and FED, the molecular mechanisms underlying these two disease entities remain to be elucidated. By using surgically removed valvular specimens from MMVP and FED patients that were categorized on the basis of echocardiographic, clinical and operative findings, a cluster of microRNAs that expressed differentially were identified. The expressions of has-miR-500, -3174, -17, -1193, -646, -1273e, -4298, -203, -505, and -939 showed significant differences between MMVP and FED after applying Bonferroni correction (p < 0.002174). The possible involvement of microRNAs in the pathogenesis of DMVD were further suggested by the presences of in silico predicted target sites on a number of genes reported to be involved in extracellular matrix homeostasis and marker genes for cellular composition of mitral valves, including decorin (DCN), aggrecan (ACAN), fibromodulin (FMOD), α actin 2 (ACTA2), extracellular matrix protein 2 (ECM2), desmin (DES), endothelial cell specific molecule 1 (ESM1), and platelet/ endothelial cell adhesion molecule 1 (PECAM1), as well as inverse correlations of selected microRNA and mRNA expression in MMVP and FED groups. Our results provide evidence that distinct molecular mechanisms underlie MMVP and FED. Moreover, the microRNAs identified may be targets for the future development of diagnostic biomarkers and therapeutics.

Background — Antiplatelet agents, beta-blockers, statins and ACE inhibitors have been shown to reduce mortality in patients following myocardial infarction (MI). However, it is uncertain if the combination of these agents has a similar impact on mortality following MI in patients with renal dysfunction. Methods — We studied 5529 consecutive patients with confirmed MI between January 2000 and December 2003. Data on baseline demographics, co-morbidities and in-hospital management were collected prospectively. Glomerular filtration rate (GFR) was estimated using the 4-component Modification of Diet in Renal Disease equation. Based on discharge use of evidence-based medications, the patients were divided into those using 0, 1, 2, 3 or 4 medications.The impact of medication use on I-year mortality was then assessed for patients with GFR ≥ 60 ml/min/1.73 m 2 (group I) and GFR < 60 ml/min/ 1.73 m 2 (group 2). Results - Mean age was 63 ± 13 years with 71% men. The prevalence of reduced GFR was 35% and the adjusted odds ratio for I-year mortality of patients in group 2 compared to those in group I was 1.86 (95% CI 1.54-2.25, P < 0.001). Compared with patients with no medication, the adjusted odds ratio for 1-year mortality was lower in patients with 1, 2, 3 and 4 medications in both groups. There was no significant interaction between the number of medications used and GFR. Conclusion - Increased use of combined evidence-based medications was independently associated with a lower I-year post MI mortality. Such therapies offer similar survival benefit in patients with and without renal dysfunction.

Atrial fibrillation (AF) has been associated with adverse outcomes in patients with severe aortic stenosis (AS) undergoing valve replacement. However, its prognosis in medically-managed patients remained under-recognized. We compared patients with AF to those without in medically-managed severe AS

Background: Mitral regurgitation (MR) is often seen in association with aortic stenosis (AS) and is known to affect prognosis in those who undergo valve replacement. MR is thought to develop in the setting of left ventricular (LV) remodeling. However, the relationship between valve pathology and LV

Introduction The treatment of aortic valve stenosis (AS) is seeing renewed interest mainly due to the availability of transcatheter therapies. However, the number of epidemiological studies of this disease in Singapore is limited. We aimed to describe the aetiology and clinical presentation of AS in Singapore, as well as patients' attitudes toward it. Our findings may facilitate the future planning and utilisation of resources to better manage these patients. Methods 249 consecutive patients who underwent transthoracic echocardiography (from April 1999 to April 2008) and diagnosed with severe AS were assessed. Demographic and clinical data were collected, and patients' decisions on surgery were determined. Results The mean patient age was 71 (range 23-98) years. 50.2% of patients were male. The commonest presenting symptom was dyspnoea, and 40 (16.0%) patients had coexistent atrial fibrillation. The aetiology of AS was degenerative in 216 (86.7%), rheumatic in 11 (4.4%) and related to a bicuspid valve in 22 (8.9%) patients. The average peak velocity across the aortic valve was 4.2 ± 0.8 m/s and the mean aortic valve area was 0.76 ± 0.13 cm2. The overall mean logistic EuroSCORE was 10.7 ± 12.3. 105 (42.2%) patients who were offered surgery refused. 87 (35%) deaths were seen during the follow-up period (mean duration 14.5 months), which also saw 68 (27%) patients undergo surgery and 86 (34%) patients hospitalised for heart failure. Conclusion Degenerative AS was the commonest aetiology in this contemporary cohort of patients. Despite the known benefits of surgery, the refusal rate for surgery remained high.

Thrombus formation can occur during the mitraclip procedure and predispose patients to significant complications from thromboembolism. This case illustrates the need to be vigilant despite anticoagulation. The entire system had to be removed and re-prepared to remove the thrombus and prevent complications. In addition, increased anticoagulation had to be administered.

We present our clinical experience of StarClose in patients undergoing coronary interventions, including its use in patients after repeated puncture of the same femoral access site.The StarClose is a novel vascular closure device that deploys a small, flexible, circumferential nitinol clip onto the femoral artery surface.In this study, 103 consecutive patients (24% with repeated punctures) who underwent percutaneous coronary intervention and received a StarClose were followed up prospectively. The patients were assessed for vascular complications prior to hospital discharge. Device success, based on time-to-hemostasis, was divided into (1) immediate success: hemostasis achieved immediately after StarClose deployment without the need for adjunctive manual compression, (2) partial success: occurrence of minor oozing after StarClose deployment and hemostasis achieved after3 minutes of manual compression, and (3) device failure: need for adjunctive manual compression for3 minutes.Immediate success, partial success, and device failure rates were 74% (n = 68), 16% (n = 15), and 10% (n = 9), respectively. There were no major complications attributable to the StarClose device. There were 10 (9.7%) cases of minor complications; all were recurrent wound bleeding requiring manual compression in the wards. Among these 10 cases of recurrent bleeding, 5 (50%) had initial device success (immediate success, n = 2, partial success, n = 3) in the catheterization laboratory. The risk for recurrent bleeding was 2.9% after immediate device success and 20.0% after partial device success.Our study found no major complications but a 10% failure rate and a 9.7% rate of minor complications. Close surveillance is important as there is a risk for recurrent bleeding, especially in patients with partial device success as defined in this report.

Until recent years, there has been limited therapeutic options for patients with pulmonary hypertension (PAH). Sildenafil, a phosphodiesterase-5 inhibitor has been the latest addition after recent positive results of the randomized control trial by the sildenafil use in Pulmonary Arterial Hypertension group [1]. These patients showed improved exercise capacity, WHO functional class and hemodynamics [2,3]. Sildenafil unfortunately has a short half life of 4 h. Repeated doses required may lead to reduced compliance. Tadalafil, a long acting PDE5 inhibitor with a half life of 18 h [4] may offer similar improvement at reduced cost and improved compliance in PAH patients. We assessed the impact of change from sildenafil to tadalafil on exercise capacity, NYHA functional class and hemodynamics in 12 patients who have had prior response to sildenafil.