Two-year outcome of ventricular assist device via a modified left atrium to aorta approach in cardiac amyloidosis.

Cardiac amyloidosis is a debilitating disease associated with poor long-term survival. Medical or palliative treatment is the usual course of therapy, but patients are often intolerant of conventional heart failure treatment. The current standard of care of sequential heart and bone marrow transplant is usually not feasible for ill or frail patients or in countries with limited organ donors or without transplant programmes. Left ventricular assist devices (LVAD) are not usually offered to these patients due to high peri-operative risks and risks of suction events with the LVAD in a small left ventricle. We report the 2 year outcome and discuss the challenges faced in the management of our patient with end-stage heart failure due to cardiac amyloidosis, who was successfully supported with an LVAD using a modified left atrium to aorta implantation technique.

2015 Young Surgeon's Award Winner: Long-term Prognosis in Patients with Diabetes Mellitus after Coronary Artery Bypass Grafting: A Propensity-Matched Study.

INTRODUCTION: We aimed to determine the impact of diabetes mellitus (DM) on long-term survival after coronary artery bypass grafting (CABG) in patients with multivessel coronary artery disease. MATERIALS AND METHODS: A retrospective review was conducted for 5720 consecutive patients who underwent isolated first CABG between 1982 and 1999. Outcomes were reviewed to include in-hospital mortality and long-term survival. Mean follow-up was 13.0 ± 5.8 years. To obtain comparable subgroups, 561 diabetic patients were matched with 561 non-diabetic controls based on estimated propensity scores. RESULTS: Mean age was 59.3 ± 9.1 years with 4373 (76.5%) males. Amongst 5720 patients, 1977 (34.6%) had DM. Hypertension and dyslipidaemia were the most common cardiovascular comorbidities, present in 2920 (51.0%) and 2664 patients (46.6%) respectively. Emergency surgery was performed in 563 patients (9.8%). In-patient mortality occurred in 115 patients (2.0%), 48 (2.4%) in the DM group and 67 (1.8%) in the non-DM group, (P = 0.102). In the unmatched cohort, overall 20-year survival rates were 30.9 ± 1.6% in diabetics and 49.2 ± 1.0% in non-diabetics (P <0.001). Freedom from cardiac mortality at 20 years was 56.0 ± 2.0% in diabetics and 68.4 ± 1.0% in non-diabetics (P <0.001). In the propensity-matched group, overall 20-year survival rates were 35.4 ± 2.5% in diabetics and 48.9 ± 2.9% in non-diabetics (P <0.001). Freedom from cardiac mortality at 20 years was 57.8 ± 3.0% in diabetics and 70.2 ± 2.9% in non-diabetics (P = 0.001). Multivariable Cox regression analysis identified age (hazard ratio (HR): 1.03/year), female gender (HR: 1.43), DM (HR: 1.51), previous myocardial infarction (HR: 1.54) and left ventricular ejection fraction (LVEF) <35% (HR: 2.60) as independent factors influencing long-term cardiac mortality. CONCLUSION: Despite low operative mortality, long-term survival and freedom from cardiac death are significantly lower in patients with DM compared to non-diabetics. Aggressive treatment of DM, cardiovascular comorbidities and smoking cessation are essential to improve long-term survival in diabetic patients.

Banking of cryopreserved iliac artery and vein homografts: clinical uses in transplantation.

Iliac artery and vein homografts are critical for revascularization in living-donor liver transplantation. Since 2010, National Cardiovascular Homograft Bank and National University Hospital have collaborated in the pioneer endeavor of banking iliac vessel homografts for such surgeries in Singapore. This article aims to demonstrate that the processing, decontamination and cryopreservation techniques that our bank follow, help preserve iliac vessel homografts for a longer duration as compared to homografts preserved using short-term preservation techniques. This paper reports the first 4 years of post-operative outcome for recipients as a preliminary report for a longer-term outcome study. Criteria for donor assessment, techniques of iliac vessel homograft recovery, processing, decontamination, cryopreservation and storage according to the American Association of Tissue Banks standards are also described. From 2010 until 2013, we discovered of the iliac vessel homografts processed, 17 (94.4 %) were suitable for clinical use. Nine iliac artery grafts (64 %) and one iliac vein graft (14 %) were implanted. Irrespective of vessel type, homografts <90 mm in length were of little use. Of the nine current iliac vessel homograft recipients, eight patients (89 %) had living-donor liver transplantation and one patient (11 %) had reconstruction of the right internal carotid artery after resection of an aneurysm. Our preliminary results supports existing literatures that suggest cryopreserved iliac vessel homografts can be successfully used for revascularization in liver transplantation and reconstruction of carotid artery. Encouraging short-term post-operative patient outcomes have been achieved, with no report of adverse event attributed to implanted homografts. We believe that our processing, decontamination and cryopreservation techniques have helped preserve the homografts for longer duration as compared to homografts preserved using short-term preservation techniques.

Pectus excavatum: uncommon electrical abnormalities caused by extrinsic right ventricular compression.

We report a case of pectus excavatum associated with ventricular tachycardia provoked by exercise in a 19-year-old man. Although this chest deformity has been associated with supraventricular dysrhythmias, documented ventricular tachycardia has only been reported once. Our patient's ventricular dysrhythmia was treated by surgical correction of his pectus excavatum only, and at 3 years follow-up he has had no recurrence of his ventricular tachycardia.

International heart valve bank survey: a review of processing practices and activity outcomes.

A survey of 24 international heart valve banks was conducted to acquire information on heart valve processing techniques used and outcomes achieved. The objective was to provide an overview of heart valve banking activities for tissue bankers, tissue banking associations, and regulatory bodies worldwide. Despite similarities found for basic manufacturing processes, distinct differences in procedural details were also identified. The similarities included (1) use of sterile culture media for procedures, (2) antibiotic decontamination, (3) use of dimethyl sulfoxide (DMSO) as a cryoprotectant, (4) controlled rate freezing for cryopreservation, and (5) storage at ultralow temperatures of below -135°C. Differences in procedures included (1) type of sterile media used, (2) antibiotics combination, (3) temperature and duration used for bioburden reduction, (4) concentration of DMSO used for cryopreservation, and (5) storage duration for released allografts. For most banks, the primary reasons why allografts failed to meet release criteria were positive microbiological culture and abnormal morphology. On average, 85% of allografts meeting release criteria were implanted, with valve size and type being the main reasons why released allografts were not used clinically. The wide variation in percentage of allografts meeting release requirements, despite undergoing validated manufacturing procedures, justifies the need for regular review of important outcomes as cited in this paper, in order to encourage comparison and improvements in the HVBs' processes.

How should I treat stent dislodgement in a STEMI patient resulting in dissection of left main and left circumflex arteries?

BACKGROUND: A 52-year-old female presented with acute anterior ST-elevation myocardial infarction (STEMI) within one hour of symptom onset to the emergency department. She was referred for urgent primary angioplasty. INVESTIGATION: Physical examination, laboratory investigations, ECG, urgent percutaneous coronary intervention (PCI). DIAGNOSIS: Single-vessel coronary artery disease (SVD). TREATMENT: Intended to stent culprit lesion. However, stent dislodged in left main coronary artery (LMCA) during attempted PCI to diffuse mid segment of left anterior descending (LAD). Initial attempt failed to retrieve the dislodged stent with snare. Dislodged stent removed with multiple wire technique, complicated by severe dissection in LAD and left circumflex artery back into the LMCA. The stent was trapped at tip of 6 Fr right femoral sheath, unable to be withdrawn. What next?

Homograft banking in Singapore: two years of cardiovascular tissue banking in Southeast Asia.

Established in 2008, the National Cardiovascular Homograft Bank (NCHB) has been instrumental in creating an available supply of cardiovascular tissues for implantation in Singapore. This article introduces its collaboration with Singapore General Hospital Skin Bank Unit. The procedure of homograft recovery, processing, cryopreservation and quality assurance are presented. Since its establishment, the NCHB has followed the guidelines set by the Ministry of Health Singapore and the American Association of Tissue Banks. A total of 57 homografts had been recovered and 40 homografts were determined to be suitable for clinical use. The most significant reasons for non-clinical use are positive microbiological culture or unsuitable graft condition. Crucial findings prompted reviews and implementation of new procedures to improve the safety of homograft recipients. These include (1) a change in antibiotic decontamination regime from penicillin and streptomycin to amikacin and vancomycin after a review and (2) mandating histopathogical examination since the discovery of cardiac sarcoidosis in a previously undiagnosed donor. Further, the NCHB also routinely performs dengue virus screening, for donors suspected of dengue infection. Cultural factors which affect the donation rate are also briefly explored. By 2010, 31 homografts had been implanted into recipients with congenital or acquired heart valve conditions. More than half of these recipients were children. Post-operative outcomes had been encouraging, with no report of adverse events attributed to implanted homografts.

Iliofemoral anatomy among Asians: implications for transcatheter aortic valve implantation.

BACKGROUND/OBJECTIVES: This study aims to examine iliofemoral anatomy and predictors of vessel size and tortuosity in Asian patients as transfemoral transcatheter aortic valve implantation (TAVI) may be limited by the smaller Asian physique. METHODS: Characteristics and vessel dimensions of 549 patients undergoing ultrasonography were reviewed. The minimal luminal diameter (MLD) along the iliofemoral vasculature of each side was identified and the larger of the two sides was used to determine suitability for transfemoral TAVI. RESULTS: The mean age was 66 ± 11 years (68% males). Mean iliac MLD was 7.6 ± 1.7 mm, females smaller than males (7.2 ± 1.7 vs 7.8 ± 1.7, p<0.001). Mean iliac MLD decreased with age: 7.9 ± 1.7 mm, 7.4 ± 1.9 mm and 7.3 ± 1.6mm for ages <70 years, 70-79 years and ≥ 80 years respectively (p=0.038). Mean femoral MLD was 7.0 ± 1.7 mm, females smaller than males (6.3 ± 1.5mm vs 7.3 ± 1.8mm, p<0.001). Females were more likely than males to have iliac and femoral MLD <6mm (20% vs 12%, p=0.019 and 34% vs 21%, p=0.001). Independent predictors of smaller iliofemoral dimensions were female gender, lower body surface area, diabetes mellitus, dyslipidemia and smoking history. Significant iliac tortuosity was present in 11.8%, more frequent in males than females (15% vs 6%, p=0.005), and in those with logistic EuroSCORE ≥ 15 than <15 (27% vs 10%, p=0.001). CONCLUSIONS: This study establishes the mean iliac and femoral artery diameters in a cohort of relatively young Asian patients. Age and female gender were associated with smaller vessel dimension and several independent predictors of smaller vasculature and tortuosity were identified. These results have implications for TF TAVI in Asia.

From penicillin-streptomycin to amikacin-vancomycin: antibiotic decontamination of cardiovascular homografts in Singapore.

BACKGROUND: In February 2012, the National Cardiovascular Homograft Bank (NCHB) became the first tissue bank outside of North America to receive accreditation from the American Association of Tissue Banks. From 2008 to 2009, NCHB had been decontaminating its cardiovascular homografts with penicillin and streptomycin. The antibiotic decontamination protocol was changed in January 2010 as amikacin and vancomycin were recommended, in order to cover bacteria isolated from post-recovery and post- antibiotic incubation tissue cultures. AIM: The objective of this study is to determine the optimal incubation conditions for decontamination of homografts by evaluating the potencies of amikacin and vancomycin in different incubation conditions. Retrospective reviews of microbiological results were also performed for homografts recovered from 2008 to 2012, to compare the effectiveness of penicillin-streptomycin versus the amikacin-vancomycin regimens. METHODS: Based on microbiological assays stated in United States Pharmacopeia 31, potency of amikacin was evaluated by turbidimetric assay using Staphylococcus aureus, while vancomycin was by diffusion assay using Bacillus subtilis sporulate. Experiments were performed to investigate the potencies of individual antibiotic 6-hours post incubation at 4°C and 37°C and 4°C for 24 hours, after the results suggested that amikacin was more potent at lower temperature. FINDINGS: Tissue incubation at 4°C for 24 hours is optimal for both antibiotics, especially for amikacin, as its potency falls drastically at 37°C. CONCLUSION: The decontamination regimen of amikacin-vancomycin at 4°C for 24 hours is effective. Nevertheless, it is imperative to monitor microbiological trends closely and evaluate the efficacy of current antibiotics regimen against emerging strains of micro-organisms.

Aortic intimal fold in Takayasu arteritis causing obstruction of left coronary ostium.

An 11-year-old girl with Takayasu arteritis was presented with recurrent chest pain. A transthoracic echocardiogram showed moderate to severe aortic regurgitation with impaired cardiac function. Cardiac catheterization revealed the total occlusion of the small right coronary artery and left main stenosis of 40%. An intraoperative transesophageal echocardiogram showed a redundant intimal fold partially covering the left coronary ostium and this was further confirmed from the intraoperative finding. This is a case report of recurrent angina associated with obstruction of left main coronary artery orifice by an intimal fold secondary to Takayasu arteritis.

Ventricular septal rupture following acute myocardial infarction.

OBJECTIVE: Ventricular septal rupture (VSR) is a complication of acute myocardial infarction (AMI) that is associated with significant mortality. We aim to review the clinical outcome in the current era. METHODS AND RESULTS: Patients admitted to a single tertiary centre from 1997 to 2008 with VSR post-AMI were identified from the local cardiac registry. We performed a retrospective review on 25 patients. Mean age (15 women) was 71 years. Most patients had cardiovascular risk factors (84%); the commonest was hypertension (72%). Anterior AMI (80%) and apical VSR (84%) formed the majority of the cases. Eleven patients (44%) received prior coronary reperfusion therapy either via thrombolysis or PCI. Median time to rupture was 1 day from diagnosis of infarction. More than half (60%) of the patients were in Killip class 3 or 4 at diagnosis of rupture. Mean left ventricular ejection fraction (LVEF) was 33 +/- 10%. Most patients (80%) required IABP for haemodynamic support. All patients who underwent surgery had ventricular septal repair; amongst them 47% had concomitant CABG. Those managed conservatively were older (P = 0.01). Overall mortality rate was 44%. Most died within the first four days (82%). Surgical and non-surgical survival rates were 68% and 17%, respectively (P= 0.039). Patient demographics, prior coronary reperfusion techniques, Killip class status and LVEF were not significant predictors of mortality. However, non-anterior wall AMI and non-apical VSR were significantly associated with poorer survival (P = 0.009, P = 0.026 respectively). CONCLUSIONS: While the occurrence ofVSR post-AMI appears to be low compared to earlier studies, it continues to be associated with significant mortality. Non-anterior wall AMI and non-apical VSR were associated with poorer survival and surgical repair conferred survival advantage over conservative management.

Single cusp replacement for aortic regurgitation.

BACKGROUND: Aortic insufficiency is a common disease in cardiac surgery. The frequency of native aortic valve repair in the young is increasing, reflecting a lack of consensus on the optimal therapeutic solution from the growing number of mechanical and biological prostheses. METHODS: Bovine pericardium was used to replace the coronary leaflet to treat aortic insufficiency in 21 patients aged 4 to 39 years (19 +/- 9.2). Aortic insufficiency was severe in 18 patients and moderate to severe in 3 patients. Seventeen patents had ventricular septal defects (VSD). One had associated rupture of the right sinus of Valsalva without VSD and 3 other patients had acquired heart disease (1 had infective endocarditis and 2 had rheumatic heart disease). RESULTS: There was no mortality. The follow-up ranged from 6 to 21 months. Thirteen patients had complete relief of aortic insufficiency, 7 had mild residual aortic insufficiency, and 1 had moderate aortic insufficiency. CONCLUSIONS: Replacement of the diseased leaflet with bovine pericardium is a promising technique for young patients. The short-term outcomes are encouraging, but longer follow-up is required to assess the durability and function of bovine pericardial leaflet in the aortic position.

Device closure of perimembranous ventricular septal defects with a minimally invasive technique in 12 patients.

BACKGROUND: Both surgical management and percutaneous device closure of perimembranous ventricular septal defects without cardiopulmonary bypass have drawbacks and limitations. This report describes the experience with intraoperative device closure of perimembranous ventricular septal defects without cardiopulmonary bypass by a minimally invasive technique. METHODS: Twelve patients who had perimembranous ventricular septal defects underwent perventricular closure by a minimally invasive incision without cardiopulmonary bypass. A subxiphoid minimally invasive incision was performed. The right ventricle free wall was punctured, and a guidewire was introduced into the right ventricular cavity. A delivery sheath was advanced over the wire and through the defect into the left ventricular cavity under the guidance of transesophageal echocardiography. The device was released under the guidance of transesophageal echocardiography without cardiopulmonary bypass. RESULTS: The procedure was successful in the 12 patients. Patients stayed in the intensive care unit 1 day and were in the hospital 4 days. At follow-up of 2 to 4 months, there was no operative mortality, atrioventricular block, new aortic incompetence, or residual shunt. CONCLUSIONS: The minimally invasive technique appeared to be safe and efficacious for closure of perimembranous ventricular septal defects in the operating room with acceptable short-term outcomes.