Incidence, microbiological profile of nosocomial infections, and their antibiotic resistance patterns in a high volume Cardiac Surgical Intensive Care Unit.

Background: Nosocomial infections (NIs) in the postoperative period not only increase morbidity and mortality, but also impose a significant economic burden on the health care infrastructure. This retrospective study was undertaken to (a) evaluate the incidence, characteristics, risk factors and outcomes of NIs and (b) identify common microorganisms responsible for infection and their antibiotic resistance profile in our Cardiac Surgical Intensive Care Unit (CSICU). Patients and Methods: After ethics committee approval, the CSICU records of all patients who underwent cardiovascular surgery between January 2013 and December 2014 were reviewed retrospectively. The incidence of NI, distribution of NI sites, types of microorganisms and their antibiotic resistance, length of CSICU stay, and patient‑outcome were determined. Results: Three hundred and nineteen of 6864 patients (4.6%) developed NI after cardiac surgery. Lower respiratory tract infections (LRTIs) accounted for most of the infections (44.2%) followed by surgical‑site infection (SSI, 11.6%), bloodstream infection (BSI, 7.5%), urinary tract infection (UTI, 6.9%) and infections from combined sources (29.8%). Acinetobacter, Klebsiella, Escherichia coli, and Staphylococcus were the most frequent pathogens isolated in patients with LRTI, BSI, UTI, and SSI, respectively. The Gram‑negative bacteria isolated from different sources were found to be highly resistant to commonly used antibiotics. Conclusion: The incidence of NI and sepsis‑related mortality, in our CSICU, was 4.6% and 1.9%, respectively. Lower respiratory tract was the most common site of infection and Gram‑negative bacilli, the most common pathogens after cardiac surgery. Antibiotic resistance was maximum with Acinetobacter spp.

Hair & skin derived progenitor cells: In search of a candidate cell for regenerative medicine.

Background & objectives: Skin is an established tissue source for cell based therapy. The hair follicle has been introduced later as a tissue source for cell based therapy. The ease of tissue harvest and multipotent nature of the resident stem cells in skin and hair follicle has promoted basic and clinical research in this area. This study was conducted to evaluate skin stem cells (SSCs) and hair follicle stem cells (HFSCs) as candidate cells appropriate for neuronal and melanocyte lineage differentiation. Methods: In this study, SSCs and hair follicle stem cells (HFSCs) were expanded in vitro by explant culture method and were compared in terms of proliferative potential and stemness; differentiation potential into melanocytes and neuronal lineage. Results: SSCs were found to be more proliferative in comparison to HFSCs, however, telomerase activity was more in HFSCs in comparison to SSCs. Capacity to differentiate into two lineages of ectoderm origin (neuronal and melanocyte) was found to be different. HFSCs cells showed more propensities towards melanocyte lineage, whereas SSCs were more inclined towards neuronal lineage. Interpretation & conclusions: The study showed that SSCs had differential advantage over the HFSCs for neuronal cell differentiation, whereas, the HFSCs were better source for melanocytic differentiation.

Culture & differentiation of mesenchymal stem cell into osteoblast on degradable biomedical composite scaffold: In vitro study.

Background & objectives: There is a significant bone tissue loss in patients from diseases and traumatic injury. The current autograft transplantation gold standard treatment has drawbacks, namely donor site morbidity and limited supply. The field of tissue engineering has emerged with a goal to provide alternative sources for transplantations to bridge this gap between the need and lack of bone graft. The aim of this study was to prepare biocomposite scaffolds based on chitosan (CHT), polycaprolactone (PCL) and hydroxyapatite (HAP) by freeze drying method and to assess the role of scaffolds in spatial organization, proliferation, and osteogenic differentiation of human mesenchymal stem cells (hMSCs) in vitro, in order to achieve bone graft substitutes with improved physical-chemical and biological properties. Methods: Pure chitosan (100CHT) and composites (40CHT/HAP, 30CHT/HAP/PCL and 25CHT/HAP/PCL scaffolds containing 40, 30, 25 parts per hundred resin (phr) filler, respectively) in acetic acid were freeze dried and the porous foams were studied for physicochemical and in vitro biological properties. Results: Scanning electron microscope (SEM) images of the scaffolds showed porous microstructure (20-300 μm) with uniform pore distribution in all compositions. Materials were tested under compressive load in wet condition (using phosphate buffered saline at pH 7.4). The in vitro studies showed that all the scaffold compositions supported mesenchymal stem cell attachment, proliferation and differentiation as visible from SEM images, [3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay, alkaline phosphatase (ALP) assay and quantitative reverse transcription (qRT)-PCR. Interpretation & conclusions: Scaffold composition 25CHT/HAP/PCL showed better biomechanical and osteoinductive properties as evident by mechanical test and alkaline phosphatase activity and osteoblast specific gene expression studies. This study suggests that this novel degradable 3D composite may have great potential to be used as scaffold in bone tissue engineering.

Efficacy of stem cell in improvement of left ventricular function in acute myocardial infarction - MI3 Trial.

Background & objectives: Acute myocardial infarction (AMI) is characterized by irreparable and irreversible loss of cardiac myocytes. Despite major advances in the management of AMI, a large number of patients are left with reduced left ventricular ejection fraction (LVEF), which is a major determinant of short and long term morbidity and mortality. A review of 33 randomized control trials has shown varying improvement in left ventricular (LV) function in patients receiving stem cells compared to standard medical therapy. Most trials had small sample size and were underpowered. This phase III prospective, open labelled, randomized multicenteric trial was undertaken to evaluate the efficacy in improving the LVEF over a period of six months, after injecting a predefined dose of 5-10 × 108 autologous mononuclear cells (MNC) by intra-coronary route, in patients, one to three weeks post ST elevation AMI, in addition to the standard medical therapy. Methods: In this phase III prospective, multicentric trial 250 patients with AMI were included and randomized into stem cell therapy (SCT) and non SCT groups. All patients were followed up for six months. Patients with AMI having left ventricular ejection fraction (LVEF) of 20-50 per cent were included and were randomized to receive intracoronary stem cell infusion after successfully completing percutaneous coronary intervention (PCI). Results: On intention-to-treat analysis the infusion of MNCs had no positive impact on LVEF improvement of ≥ 5 per cent. The improvement in LVEF after six months was 5.17 ± 8.90 per cent in non SCT group and 4.82 ± 10.32 per cent in SCT group. The adverse effects were comparable in both the groups. On post hoc analysis it was noted that the cell dose had a positive impact when infused in the dose of ≥ 5 X 108 (n=71). This benefit was noted upto three weeks post AMI. There were 38 trial deviates in the SCT group which was a limitation of the study. Interpretation & conclusions: Infusion of stem cells was found to have no benefit in ST elevation AMI. However, the procedure was safe. A possible benefit was seen when the predefined cell dose was administered which was noted upto three weeks post AMI, but this was not significant and needs confirmation by larger trials.

Double aortic arch as a source of airway obstruction in a child.

Double aortic arch (DAA) is a congenital vascular anomaly. The diagnosis was difficult till the child was symptomatic, and other causes were ruled out. We present the interesting images of a child of respiratory distress because of tracheal compression from DAA.

Use of extracorporeal membrane oxygenator support to salvage an infant with anomalous left coronary artery from pulmonary artery.

Anomalous left coronary artery from pulmonary artery (ALCAPA) is a congenital acyanotic heart disease where the left coronary artery (LCA) arises from the pulmonary artery. This results in the LCA receiving blood supply from the low-pressure right ventricle having minimal extractable oxygen. The oxygen delivery to the left ventricle (LV) is severely hampered causing severe hypoxic LV dysfunction early in life. Early surgery prior to serious, irreversible LV dysfunction is the key to survival. Children with ALCAPA usually present in their first few weeks of life, with severe LV dysfunction. After surgical correction of the defect, the myocardium may not recover early from the presurgery myocardial dysfunction. We describe a case where extracorporeal membrane oxygenator was utilized as a means of ventricular support during this critical postoperative period resulting in a favorable outcome.

Comparison of straight sternotomy and interlocking sternotomy in open heart surgery.

BACKGROUND AND OBJECTIVES: Stable sternal approximation is an important factor to avoid respiratory complications after open heart surgery. The present study is designed to compare interlocking sternotomy and straight sternotomy in terms of sternal stability, pain and respiratory function. METHODS: Sixty patients scheduled for open heart surgery underwent a standard midline sternotomy (n=30) or an interlocking sternotomy (n=30). The features assessed were pain on visual analogue scale during rest and during cough, peak expiratory flow rate and sternal instability. Evaluation was performed on the first, fourth post-operative days, on discharge and one month and three month follow up. RESULTS: Analysis of the peak expiratory flow rates, visual analogue ratings of pain intensity at rest and on coughing were carried out for each group only for those patients who completed the study. Postoperatively, in all patients there was significant reduction in peak expiratory flow rates. In the straight sternotomy group resting pain intensity was higher on discharge (2.6+/- 2 vs 1.6 +/- 2.3, P= 0.005). In the interlocking sternotomy group pain on coughing was significantly less than straight sternotomy group (median 0.5 vs 2.8, P=0.005) at 1 month follow up and at 3 months (median 0 vs 1.6, P=0.003). INTERPRETATION AND CONCLUSION: Interlocking sternotomy can be performed with good functional results and offers a less painful alternative to straight sternotomy.

Congestive heart failure in unoperated tetralogy of Fallot: can hypoxia be a cause?

A 10-year-old boy with tetralogy of Fallot and congestive heart failure underwent a right-sided modified Blalock-Taussig anastomosis because of severe biventricular dysfunction and repeated hypercyanotic spells. Postoperatively, there was improvement in systemic oxygen saturation and myocardial function. We postulate that congestive heart failure occurred because of severe myocardial hypoxia and its elimination resulted in markedly improved cardiac performance.

Transatrial permanent pacing lead implantation in a patient of Ebstein's anomaly after one and half repair.

Several innovative approaches have been described to achieve endocardial pacing in patients with operated complex congenital heart diseases. We report herein a case of Ebstein's anomaly who underwent a Hardy's repair with a bidirectional Glenn shunt, tricuspid valve annuloplasty and atrial septal defect closure following which she developed complete heart block. The chest was reopened through the previous midsternotomy and a screw-in lead implanted transatrially that resulted in optimal pacing thresholds. This technique offers a viable alternative for endocardial pacing in peri-operative patients requiring permanent pacing.

Surgical outcome of staged univentricular-type repairs for patients with univentricular physiology and pulmonary hypertension.

BACKGROUND: There is no consensus about the most appropriate limits of pulmonary artery pressure and vascular resistance in case of patients undergoing univentricular or one and one-half ventricular repair. This study was conducted to analyze the mortality and morbidity of a heterogenous group of patients with a functionally univentricular heart and pulmonary artery hypertension, undergoing pulmonary artery banding followed by univentricular-type repairs. METHODS AND RESULTS: Out of 254 patients undergoing pulmonary artery banding for a functionally univentricular heart with increased pulmonary blood flow, 148 patients underwent definitive second stage surgery. Post-band hemodynamic evaluation revealed persistently high pulmonary artery pressure (> 18 mmHg), and pulmonary vascular resistance (>2.0 Woods units/m2) in 78.3% patients. Sixteen patients with moderate right ventricular hypoplasia were given a one and one-half ventricle repair (Group I), 82 patients a bidirectional Glenn connection (Group II), and 50 patients a fenestrated total cavopulmonary connection (Group III). The overall mortality following second stage surgery for the high pulmonary artery pressure group (n=116) was 30.17%, while none of the low pulmonary artery pressure group died (p=0.0009). Pulmonary hypertensive crises and/or systemic desaturation were the main causes of death at second stage repair. All mortality occurred in patients with mean pulmonary artery pressure > 18 mmHg and pulmonary vascular resistance > 3.5 Woods units/m2. Survivors from this group had persistent morbidity in the form of superior vena caval syndrome and suboptimal oxygen saturation (70-75%). CONCLUSIONS: It is advisable not to proceed with definitive second stage repair if post-pulmonary artery banding mean pulmonary artery pressure is over 25 mmHg and pulmonary vascular resistance exceeds 4.0 Woods units/m2. These patients may possibly be deemed to have undergone definitive palliation during their pulmonary artery banding.

Giant pulmonary artery aneurysm with right ventricular outflow tract obstruction.

Aneurysm of the main pulmonary artery is rare. Its natural history is not well understood and there are no clear guidelines regarding its optimal treatment. We present a case of a huge saccular aneurysm of the main pulmonary artery which was associated with infundibular and valvular pulmonary stenosis. It was repaired using a pericardial patch with concomitant pulmonary valvotomy and infundibular resection. Postoperative recovery was uneventful and the patient is doing well. Follow-up echocardiogram revealed good repair.

Ventricular septal defect with congenital mitral valve disease: long-term results of corrective surgery.

BACKGROUND: A retrospective analysis of the mortality, morbidity and long-term follow-up of patients undergoing corrective surgery for ventricular septal defect and congenital mitral valve disease is presented. METHODS AND RESULTS: Between January 1991 and December 2000, 69 consecutive patients aged 2 months to 45 years (median 18 months) underwent repair of ventricular septal defect and associated mitral valve disease. In 52 patients (75%), the ventricular septal defects were located in the perimembranous and subarterial area. Forty-six patients had congenital mitral incompetence and 23 had congenital mitral stenosis. The ventricular septal defect was repaired through the right atrium in all. Sixty-five patients underwent reconstruction of the mitral valve and 4 underwent primary mitral valve replacement. Another 4 patients underwent mitral valve replacement after a failed repair. Associated procedures included: patent ductus arteriosus ligation (n=12), aortic valve replacement (n=6), coarctation repair (n=13), interrupted aortic arch repair (n=1), atrial septal defect closure (n=17) and Takeuchi repair (n=1). There were 6 early deaths (8.6%). Three deaths were due to pulmonary arterial hypertensive crisis and one due to residual mitral stenosis. One death was due to intractable congestive heart failure. Another patient died due to persistent low cardiac output. Follow-up ranged from 6 months to 120 months (mean 64.4+/-33.6 months). Reoperation was required in 22 patients, mainly for recurrent/residual mitral valve dysfunction or hemodynamically significant left ventricular outflow tract obstruction. There were 4 late deaths, 2 due to residual mitral stenosis and the other 2 as a result of a thrombosed prosthetic valve. At 10 years, the actuarial survival rate was 850+/-5.0%, and freedom from reoperation was 45%+/-10.0%. CONCLUSIONS: Reconstruction of the mitral valve along with closure of VSD is possible in most cases. However, careful follow-up is recommended to detect changes in the mitral valve status over a course of time.