Research

Vallely MP, Yan TD, Edelman JJ, Hayman M, Brereton RJ, Ross DE

Heart Lung Circ 2010 Sep;19(9):555-60

PMID: 20447865

Abstract

Several large series have demonstrated that performing off-pump coronary artery bypass surgery without manipulating the ascending aorta (anaortic) utilising all-arterial grafts provides superior protection against neurological injury. Recent series comparing percutaneous coronary intervention (PCI) with surgical revascularisation have demonstrated superior results for surgery over PCI. However, a significant criticism of coronary artery surgery remains the higher incidence of neurological injury when compared to PCI. We present a simple and reproducible technique for anaortic, total-arterial off-pump coronary artery revascularisation.

Cao CQ, Munkholm-Larsen S, Yan TD

Zhongguo Fei Ai Za Zhi 2010 Mar;13(3):242-6

PMID: 20681068

Abstract

Vallely MP, Ross DE

Ann. Thorac. Surg. 2010 Aug;90(2):700-1; author reply 701

PMID: 20667399

Abstract

Vallely MP, Bannon PG, Bayfield MS, Hughes CF, Kritharides L

Heart Lung Circ 2010 Aug;19(8):445-52

PMID: 20418159

Abstract

BACKGROUND: The effects of off-pump coronary artery bypass (OPCAB) surgery on endothelial cell activation are poorly understood. Endothelial cell adhesion molecules (CAMs) are expressed and released when the endothelium is activated. We compared plasma CAMs (E-selectin, ICAM-1 and VCAM-1) and HUVEC expression of the same CAMs when exposed to plasma taken before, during and after OPCAB or on-pump coronary surgery (CABG).

METHODS: Patients undergoing first time CABG (n=10) or OPCAB (n=10) had 6 blood samples taken before surgery and up to 24h post-operatively. Plasma samples were assayed for E-selectin, ICAM-1 and VCAM-1. The same plasma samples were exposed to HUVEC cultures and cell-surface expression of E-selectin, ICAM-1 and VCAM-1 measured. Data are expressed as mean+/-SEM of n subjects.

RESULTS: Plasma E-selectin was unchanged. Plasma ICAM-1 and VCAM-1 were elevated 24h post-operatively in both groups (P<0.01), with no differences between the groups. Twenty-four hours post-OPCAB plasma increased basal and IL-1beta induced expression of endothelial VCAM-1 by 133+/-16% and 140+/-27% (P<0.05), respectively. Plasma taken 3h post-CABG decreased endothelial VCAM-1 expression by 76+/-10% (P<0.05). Peri-operative plasma had no effect on endothelial expression of E-selectin or ICAM-1 in either group.

CONCLUSIONS: OPCAB and CABG with CPB appear to generate qualitatively different inflammatory responses with respect to endothelial activation, which may have clinical implications.

Byrom MJ, Bannon PG, White GH, Ng MK

J. Vasc. Surg. 2010 Jul;52(1):176-95

PMID: 20299181

Abstract

The development of an ideal small-diameter conduit for use in vascular bypass surgery has yet to be achieved. The ongoing innovation in biomaterial design generates novel conduits that require preclinical assessment in vivo, and a number of animal models have been used for this purpose. This article examines the rationale behind animal models used in the assessment of small-diameter vascular conduits encompassing the commonly used species: baboons, sheep, pigs, dogs, rabbits, and rodents. Studies on the comparative hematology for these species relative to humans are summarized, and the hydrodynamic values for common implant locations are also compared. The large- and small-animal models are then explored, highlighting the characteristics of each that determine their relative utility in the assessment of vascular conduits. Where possible, the performance of expanded polytetrafluoroethylene is given in each animal and in each location to allow direct comparisons between species. New challenges in animal modeling are outlined for the assessment of tissue-engineered graft designs. Finally, recommendations are given for the selection of animal models for the assessment of future vascular conduits.

Teimoori-Toolabi L, Vahedi H, Mollahajian H, Kamali E, Hajizadeh-Sikaroodi S, Zeinali S, Tabrizian T, Olfati G, Rashtak S, Malekzadeh F, Ghoddosi A, Malekzadeh R

Hepatogastroenterology 2010 Mar-Apr;57(98):275-82

PMID: 20583427

Abstract

BACKGROUND/AIMS: Crohn’s disease frequency has increased in recent years in Iran. Genetic and environmental factors predispose people to this disease. Mutation in Caspase Recruitment Domain 15 (CARD15) gene is the most well known genetic predisposing factor to this disease. Frequency of three common CARD15 mutations has been studied in different ethnic groups. We aimed to study the frequency of these mutations in Iranian patients affected with Crohn’s Disease.

METHODOLOGY: One hundred fifteen proved cases of Crohn Disease and 115 age and sex matched normal controls were recruited in this study. Lf1007fs, R702W and G908R mutations were studied by Polymerase Chain Reaction-Restriction Fragment Length Polymorphims (PCR-RFLP) followed by sequencing the positive cases.

RESULTS: Lf1007fs and G908R mutations were not found in either patients or age-sex matched controls. Just in two patients, R702W mutation was proved by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) and sequencing. None of these patients had illeal or fibrostenotic type of disease while 14.7% of total patients had stricturing type of disease. No complication was seen in these two patients while 50.4% of patients had acquired complications during the course of disease.

CONCLUSION: The three mutations described are not responsible for the pathogenesis of Crohn’s Disease in Iranians. The results are in accordance with other Asian nations’ studies on IBD Patients.

Yan TD, Cao C, Martens-Nielsen J, Padang R, Ng M, Vallely MP, Bannon PG

J. Thorac. Cardiovasc. Surg. 2010 Jun;139(6):1519-28

PMID: 19846124

Abstract

OBJECTIVES: The present systematic review objectively assessed the safety and clinical effectiveness of transcatheter aortic valve implantation for patients at high surgical risk with severe aortic stenosis.

METHODS: Electronic searches were performed in 6 databases from January 2000 to March 2009. The end points included feasibility, safety, efficacy, and durability. Clinical effectiveness was synthesized through a narrative review with full tabulation of results of all included studies.

RESULTS: The current evidence on transcatheter aortic valve implantation for aortic stenosis is limited to short-term observational studies. The overall procedural success rates ranged from 74% to 100%. The incidence of major adverse events included 30-day mortality (0%-25%), major ventricular tachyarrhythmia (0%-4%), myocardial infarction (0%-15%), cardiac tamponade (2%-10%), stroke (0%-10%), conversion to surgery (0%-8%), moderate to major paravalvular leak (4%-35%), vascular complication (8%-17%), valve-in-valve procedure (2%-12%), and aortic dissection/perforation (0%-4%). The overall 30-day major adverse cardiovascular and cerebral events ranged from 3% to 35%. The mean aortic valve area ranged from 0.5 to 0.8 cm(2) before and 1.3 to 2.0 cm(2) after transcatheter aortic valve implantation. The mean pressure gradient ranged from 34 to 58 mm Hg before and 3 to 12 mm Hg after transcatheter aortic valve implantation. There was no significant deterioration in echocardiography measurements during the assessment period. Death rate at 6 months postprocedure ranged from 18% to 48%. No studies had adequate follow-up to reliably evaluate long-term outcomes.

CONCLUSIONS: The procedure has a potential for serious complications. Although short-term efficacy based on echocardiography measurements is good, there is little evidence on long-term outcomes. The use of transcatheter aortic valve implantation should be considered only within the boundaries of clinical trials.

Sy RW, Bannon PG, Bayfield MS, Brown C, Kritharides L

Circ Cardiovasc Qual Outcomes 2009 Sep;2(5):469-74

PMID: 20031879

Abstract

BACKGROUND: Recent studies in infective endocarditis have suggested an association between surgery and reduced mortality. However, these studies did not account for survivor treatment selection bias, which is an underrecognized source of error in observational studies. Therefore, we sought to evaluate the effects of survivor bias on surgical outcomes in infective endocarditis.

METHODS AND RESULTS: We studied 223 patients admitted with left-sided infective endocarditis between 1996 and 2006 and compared all-cause mortality between surgically treated and medically treated patients using Cox regression analysis. Propensity scores were used to account for selection bias, and time-dependent analyses were performed to account for survivor bias. Compared with medical patients (n=161), surgical patients (n=62) had lower mortality during a median follow-up of 5.2 years (32% versus 51%; P=0.02) with an unadjusted hazard ratio of 0.54 (95% CI, 0.33 to 0.88, P=0.01). After adjustment for baseline differences in propensity for surgery and risk of mortality, there remained a significant benefit for surgery (hazard ratio, 0.50; 95% CI, 0.28 to 0.88; P=0.02). However, this was diminished after time-dependent analysis (hazard ratio, 0.77; 95% CI, 0.42 to 1.40; P=0.39). Conditional Kaplan-Meier analyses confirmed the effect of survivor bias because the apparent benefit of surgery was primarily attributable to excess mortality in the medical group during early hospitalization when surgery was not frequently performed.

CONCLUSIONS: Survivor bias significantly affects the evaluation of surgical outcomes in infective endocarditis, and it should be considered in other areas of outcomes research where randomized controlled trials are not feasible. Survivor bias is not corrected by propensity analysis alone but may be reduced by time-dependent survival analysis.

Yan TD, Boyer M, Tin MM, Wong D, Kennedy C, McLean J, Bannon PG, McCaughan BC

J. Thorac. Cardiovasc. Surg. 2009 Sep;138(3):619-24

PMID: 19698846

Abstract

OBJECTIVE: This study aimed to evaluate the perioperative and long-term outcomes associated with extrapleural pneumonectomy for patients with malignant pleural mesothelioma.

METHODS: From October 1994 to April 2008, 70 patients were selected for extrapleural pneumonectomy. Univariate analysis was performed using the Kaplan-Meier method and compared using the log-rank test. Multivariate analysis with entering and removing limits of P less than .10 and P greater than .05, respectively, was used. The prognostic factors included age, gender, side of disease, asbestos exposure, histology, positron emission tomography, date of surgery, neoadjuvant chemotherapy, completeness of cytoreduction, lymph node involvement, perioperative morbidity, adjuvant radiotherapy, and pemetrexed-based chemotherapy.

RESULTS: The mean age of patients was 55 years (standard deviation = 10). Fifty-eight patients had epithelial tumors. Six patients received neoadjuvant chemotherapy, 28 patients received adjuvant radiotherapy, and 16 patients received postoperative pemetrexed-based chemotherapy. Forty-four patients had no lymph node involvement. The perioperative morbidity and mortality were 37% and 5.7%, respectively. Complications included hemothorax (n = 7), atrial fibrillation (n = 6), empyema (n = 4), bronchopulmonary fistula (n = 3), right-sided heart failure (n = 2), pneumonia (n = 1), constrictive pericarditis (n = 1), acute pulmonary edema (n = 1), small bowel herniation (n = 1), and disseminated intravascular coagulopathy (n = 1). The median survival was 20 months, with a 3-year survival of 30%. Asbestos exposure, negative lymph node involvement, and receipt of adjuvant radiation or postoperative pemetrexed-based chemotherapy were associated with improved survival on both univariate and multivariate analyses.

CONCLUSION: The present study supports the use of extrapleural pneumonectomy-based multimodal therapy in carefully selected patients with malignant pleural mesothelioma.

Yan TD, Black D, Bannon PG, McCaughan BC

J. Clin. Oncol. 2009 May;27(15):2553-62

PMID: 19289625

Abstract

PURPOSE: The current randomized trials comparing video-assisted thoracic surgery (VATS) lobectomy with open lobectomy for patients with early-stage non-small-cell lung cancer (NSCLC) have been of small size. We performed the present meta-analysis of the randomized and nonrandomized comparative studies in an attempt to assess the safety and efficacy of VATS lobectomy.

METHODS: Electronic searches identified 21 eligible comparative studies (two randomized and 19 nonrandomized) for inclusion. Two reviewers independently appraised each study. Meta-analysis was performed by combining the results of reported incidence of morbidity and mortality, recurrence, and 5-year mortality rates. The relative risk (RR) was used as a summary statistic.

RESULTS: There were no significant statistical differences between VATS and open lobectomy in terms of postoperative prolonged air leak (P = .71), arrhythmia (P = .86), pneumonia (P = .09), and mortality (P = .49). VATS did not demonstrate any significant difference in locoregional recurrence (P = .24), as compared with the open lobectomy arm, but the data suggested a reduced systemic recurrence rate (P = .03) and an improved 5-year mortality rate of VATS (P = .04). There was no evidence to suggest heterogeneity of trial results. Fourteen studies reported VATS to open lobectomy conversion rate ranging from 0% to 15.7% (median = 8.1%).

CONCLUSION: Both randomized and nonrandomized trials suggest that VATS lobectomy is an appropriate procedure for selected patients with early-stage NSCLC when compared with open surgery.