Benjamin Wan

A meta-analysis of deep hypothermic circulatory arrest versus moderate hypothermic circulatory arrest with selective antegrade cerebral perfusion

INTRODUCTION A recent concern of deep hypothermic circulatory arrest (DHCA) in aortic arch surgery has been its potential association with increased risk of coagulopathy, elevated inflammatory response and end-organ dysfunction. Recently, moderate hypothermic circulatory arrest (MHCA) with selective antegrade circulatory arrest (SACP) seeks to negate potential hypothermia-related morbidities, while maintaining adequate neuroprotection. The present meta-analysis aims to compare postoperative outcomes in arch surgery using DHCA or MHCA+SACP as neuroprotective strategies. METHODS Electronic searches were performed using six databases from their inception to January 2013. Two reviewers independently identified all relevant studies comparing DHCA with MHCA+SACP, as defined by a recent hypothermia temperature consensus. Data were extracted and meta-analyzed according to pre-defined clinical endpoints. RESULTS Nine comparative studies were identified for inclusion in the present meta-analysis. Stroke rates were significantly lower in patients undergoing MHCA+SACP (P=0.0007, I(2)=0%), while comparable results were observed with temporary neurological deficit, mortality, renal failure or bleeding. Infrequent and inconsistent reporting of systemic outcomes precluded analysis of other systemic outcomes. CONCLUSIONS The present meta-analysis indicated the superiority of MHCA+SACP in terms of stroke risk.

A systematic review and meta-analysis on the safety and efficacy of the frozen elephant trunk technique in aortic arch surgery

BACKGROUND The treatment of complex pathologies of the aortic arch and proximal descending aorta represents a significant challenge for cardiac surgeons. Various surgical techniques and prostheses have been implemented over the past several decades, all with varying degrees of success. The introduction of the frozen elephant trunk (FET) technique facilitates one-stage repair of such pathologies. The present systematic review and meta-analysis aims to assess the safety and efficacy of the FET approach in the current literature. METHODS Electronic searches were performed using six databases from their inception to July 2013. Relevant studies utilizing the FET technique were identified. Data were extracted and analyzed according to predefined clinical endpoints. RESULTS Seventeen studies were identified for inclusion for qualitative and quantitative analyses, all of which were observational reports. Pooled mortality was 8.3%, while stroke and spinal cord injuries were 4.9% and 5.1% respectively. Cardiopulmonary bypass time, myocardial ischemia time, and circulatory arrest time strongly correlated with perioperative mortality in a linear relationship, while moderate correlations between cerebral perfusion time and mortality, and circulatory arrest time and spinal cord injury, were also identified. Five-year survival, reported in five studies, ranged between 63-88%. CONCLUSIONS Overall, results of the present systematic review and meta-analysis suggest that the FET procedure can be performed with acceptable mortality and morbidity risks.

A systematic review on the safety and efficacy of percutaneous edge-to-edge mitral valve repair with the MitraClip system for high surgical risk candidates

Background MitraClip implantation has emerged as a viable option in high surgical risk patients with severe mitral regurgitation (MR). We performed the present systematic review to assess the safety and efficacy of the MitraClip system for high surgical risk candidates with severe organic and/or functional MR. Methods Six electronic databases were searched for original published studies from January 2000 to March 2013. Two reviewers independently appraised studies, using a standard form, and extracted data on methodology, quality criteria, and outcome measures. All data were extracted and tabulated from the relevant articles’ texts, tables, and figures and checked by another reviewer. Results Overall 111 publications were identified. After applying selection criteria and removing serial publications with accumulating number of patients or increased length of follow-up, 12 publications with the most complete dataset were included for quality appraisal and data extraction. All 12 studies were prospective observational studies. Immediate procedural success ranged from 72–100%; 30 day mortality ranged from 0–7.8%. There was a significant improvement in haemodynamic profile and functional status after implantation. One year survival ranged from 75–90%. No long term outcomes have been reported for high surgical risk patients. Conclusions MitraClip implantation is an option in managing selected high surgical risk patients with severe MR. The current evidence suggests that MitraClip can be implanted with reproducible safety and feasibility profile in this subgroup of patients. Further prospective trials with mid- to long-term follow-up are required.

A meta-analysis of deep hypothermic circulatory arrest alone versus with adjunctive selective antegrade cerebral perfusion.

INTRODUCTION Recognizing the importance of neuroprotection in aortic arch surgery, deep hypothermic circulatory arrest (DHCA) now underpins operative practice as it minimizes cerebral metabolic activity. When prolonged periods of circulatory arrest are required, selective antegrade cerebral perfusion (SACP) is supplemented as an adjunct. However, concerns exist over the risks of SACP in introducing embolism and hypo- and hyper-perfusing the brain. The present meta-analysis aims to compare postoperative outcomes in arch surgery using DHCA alone or DHCA + SACP as neuroprotection strategies. METHODS Electronic searches were performed using six databases from their inception to January 2013. Two reviewers independently identified all relevant studies comparing DHCA alone with DHCA + SACP. Data were extracted and meta-analyzed according to pre-defined clinical endpoints. RESULTS Nine comparative studies were identified in the present meta-analysis, with 648 patients employing DHCA alone and 370 utilizing DHCA + SACP. No significant differences in temporary or permanent neurological outcomes were identified. DHCA + SACP was associated with significantly better survival outcomes (P=0.008, I(2)=0%), despite longer cardiopulmonary bypass time. Infrequent and inconsistent reporting of other clinical results precluded analysis of systemic outcomes. CONCLUSIONS The present meta-analysis indicate the superiority of DHCA + SACP in terms of mortality outcomes.

Prognostic value of TTF-1 expression in patients with non-small cell lung cancer: a meta-analysis

Background: Observational studies on the prognostic role of thyroid transcription factor 1 (TTF-1) in non-small cell lung cancer (NSCLC) are controversial. Methods: To clarify the impact of TTF-1 in NSCLC survival, we performed this meta-analysis that included eligible studies. The combined hazard ratios and their corresponding 95% confidence intervals were calculated in terms of overall survival. Results: A total of 17 studies with 2,235 patients were evaluable for this meta-analysis. The studies were categorized by histology, disease stage and patient race. Our results suggested that TTF-1 overexpression had a favorable impact on survival of patients with NSCLC, the HR (95% CI) was 0.49 (0.42 to 0.55) overall, 0.46 (0.38-0.54) in Asian patients, 0.52 (0.42-0.63) in non-Asian patients, 0.45 (0.38-0.52) in adenocarcinoma, 0.63 (0.39-0.86) in stage I NSCLC, 0.43 (0.33-0.53) in stage IIIb-IV NSCLC. The data collected were not sufficient to determine the prognostic value of VEGF in patients with squamous cell lung carcinomas. But there was a high heterogeneity between the studies. Conclusions: TTF-1 overexpression indicates a favorable prognosis for patients with NSCLC, this effect appears also significant when the analysis is restricted in lung AC patients, stage I and stage IIIb-IV NSCLC.

Systematic review protocol: the frozen elephant trunk approach in aortic arch surgery

BACKGROUND Surgical management of aortic arch pathologies still faces significant challenges, especially if the pathology involves the proximal descending aorta. A novel solution, named the frozen elephant trunk approach, encompasses a hybrid stent-graft that is placed during conventional arch surgery in the descending aorta to exert an expansive radial force. This obviates the need for second-stage surgery, while limiting the residual patency of the false lumen and minimizing wall stress. The objective of this systematic review is to assess the safety and efficacy of the frozen elephant trunk technique in aortic ach pathologies. SELECTION CRITERIA We included all studies that used hybrid-stent grafts, or stented the proximal descending aorta under direct visualization during conventional arch surgery. Six electronic databases were searched (inception to June 2013), limited to studies that have reported 10 patients or more in the English language. MAIN RESULTS Sixteen observational studies, with 1,409 patients, were identified. A variety of commercial and custom-made stent-grafts were used, with varying pathology indications. Overall mortality was 8.5% (range, 0-18.2%). One-year survival, reported in six studies, was 85.6% (range, 70-97%), while five-year survival was 71.5% (range, 63-88%). Stroke and spinal cord injury was identified in 5.3% and 5.5% of patients respectively, while renal failure and reoperation for bleeding was 12.0% and 8.9% respectively. No other endpoints were sufficiently reported. IMPLICATIONS FOR CLINICAL PRACTICE The frozen elephant trunk approach represents a reasonably safe procedure to repair the arch and proximal descending aorta. While promising, these results require long-term studies to assess durability and freedom from reoperation. Further regulatory approval is also required to permit widespread employment of specialized commercial hybrid stent-grafts.