Stewart R. Walsh

Endovascular stenting versus open surgery for thoracic aortic disease : Systematic review and meta-analysis of perioperative results

BACKGROUND Endovascular stenting has emerged as an alternative to open repair in patients requiring surgery for thoracic aortic pathology. A number of comparative series have been published but, to date, there has been no meta-analysis comparing outcomes following stenting as opposed to open surgery. METHODS Electronic abstract databases and conference proceedings were searched to identify relevant series. Pooled odds ratios were calculated using random effects models for perioperative mortality, neurological injury, and major reintervention. RESULTS The search identified 17 eligible series, totaling 1109 patients (538 stenting). Stenting was associated with a significant reduction in mortality (pooled odds ratio 0.36; 95% CI 0.228-0.578; P < .0001) and major neurological injury (pooled odds ratio 0.39; 95% CI 0.25-0.62; P = .0001). There was no difference in the major reintervention rate (pooled odds ratio 0.91; 95% CI 0.610-1.619). There was a reduction in hospital and critical care stay although there was evidence of heterogeneity and bias with respect to these outcomes. Subgroup analyses suggested that endovascular repair reduced mortality (pooled odds ratio 0.25; 95% CI 0.09-0.66) and neurological morbidity (pooled odds ratio 0.28; 95% CI 0.13-0.61) in stable patients undergoing repair of thoracic aortic aneurysms. There was no effect on mortality in patients with thoracic aortic trauma but neurological injury was reduced (pooled odds ratio 0.17; 95% CI 0.03-1.03). Endovascular repair did not confer any apparent benefit over open surgery in patients with thoracic aortic rupture. CONCLUSION Endovascular thoracic aortic repair reduces perioperative mortality and neurological morbidity in patients with descending thoracic aortic aneurysms. There may be less benefit in other thoracic aortic conditions.

The Value of Modified Early Warning Score (MEWS) in Surgical In-Patients: A Prospective Observational Study

INTRODUCTION The Modified Early Warning Score (MEWS) is a simple, physiological score that may allow improvement in the quality and safety of management provided to surgical ward patients. The primary purpose is to prevent delay in intervention or transfer of critically ill patients. PATIENTS AND METHODS A total of 334 consecutive ward patients were prospectively studied. MEWS were recorded on all patients and the primary end-point was transfer to ITU or HDU. RESULTS Fifty-seven (17%) ward patients triggered the call-out algorithm by scoring four or more on MEWS. Emergency patients were more likely to trigger the system than elective patients. Sixteen (5% of the total) patients were admitted to the ITU or HDU. MEWS with a threshold of four or more was 75% sensitive and 83% specific for patients who required transfer to ITU or HDU. CONCLUSIONS The MEWS in association with a call-out algorithm is a useful and appropriate risk-management tool that should be implemented for all surgical in-patients.

Systematic review and meta-analysis of preoperative antisepsis with chlorhexidine versus povidone-iodine in clean-contaminated surgery.

Surgical‐site infection increases morbidity, mortality and financial burden. The preferred topical antiseptic agent (chlorhexidine or povidone–iodine) for preoperative skin cleansing is unclear.

Neurological complications after left subclavian artery coverage during thoracic endovascular aortic repair: a systematic review and meta-analysis.

INTRODUCTION Recent studies suggest an increased risk of neurologic complications after coverage of the left subclavian artery (LSA) during thoracic endovascular aortic repair (TEVAR). The preventative role of preoperative revascularization of the LSA using carotid-subclavian bypass or transposition remains controversial. We assessed this increased risk and the role of revascularization by undertaking a systematic review and meta-analysis of the literature. METHODS In the absence of any randomized controlled trials, the Pubmed and Embase databases were searched to identify all series reporting TEVAR without LSA coverage compared with LSA coverage with and without revascularization. The incidence of neurologic complications, namely cerebrovascular accident (CVA) and spinal cord ischemia (SCI), were recorded for each group. Pooled odds ratios (POR) were then calculated for postoperative CVA and SCI. RESULTS Compared with patients without LSA coverage, the risk of CVA was increased both in patients with LSA coverage alone (4.7% vs 2.7%; POR, 2.28; 95% confidence interval [CI], 1.28-4.09; P = .005) and in those with LSA coverage after revascularization (4.1% vs 2.6%; POR, 3.18; 95% CI, 1.17-8.65; P = .02). The risk of SCI was also increased in patients requiring LSA coverage (2.8% vs 2.3%; POR, 2.39; 95% CI, 1.30-4.39; P = .005) but not for LSA coverage after revascularization (0.8% vs 2.7%; POR, 1.69; 95% CI, 0.56-5.15; P = .35). CONCLUSION The risk of neurologic complications is increased after coverage of the LSA during TEVAR. Preemptive revascularization offers no protection against CVA, perhaps indicating a heterogeneous etiology. Revascularization may reduce the risk of SCI, although limited data tempers this conclusion. Improved or perhaps compulsory reporting to registries of a minimum data set may help further assess the exact etiology of these complications and identify a higher-risk subset of patients in whom revascularization might prove protective.

Iron Oxide Particles for Atheroma Imaging

The selection of patients for vascular interventions has been solely based on luminal stenosis and symptomatology. However, histological data from both the coronary and carotid vasculature suggest that other plaque features such as inflammation may be more important in predicting future thromboembolic events. Ultrasmall superparamagnetic iron oxide (USPIO) contrast agents have been used for noninvasive MRI assessment of atherosclerotic plaque inflammation in humans. It has reached the stage of development to have been recently used in an interventional drug study to not only assess inflammatory progression but also select patients at high risk. This article reviews the basic science behind the use of USPIO contrast agents in atheroma MR imaging, experimental work in animals, and how this has led to the emergence of this promising targeted imaging platform for assessment of high risk carotid atherosclerosis in humans.

Renal Consequences of Endovascular Abdominal Aortic Aneurysm Repair

Endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA) is less invasive and has a lower operative mortality than conventional surgery. The relationship between renal function and outcome following open AAA repair has been extensively investigated, but less work has been undertaken with respect to renal function and outcome after EVAR. We reviewed the literature (Medline and PubMed databases) between 1991 and 2007 to investigate the relationship between EVAR and renal dysfunction. Our review found that perioperative renal dysfunction is attenuated by EVAR. However, dialysis rates after EVAR are similar to those after open surgery. EVAR patients develop progressive deterioration in renal function over time. The etiology is unclear and probably multifactorial, involving embolization, contrast media, and graft misplacement. The effect of transrenal endograft fixation on long-term renal function is unknown, but the technique may be associated with a significantly increased risk of renal infarction. The etiology of the renal injury during and after EVAR needs further evaluation, and techniques aimed at renal preservation should be pursued.

Ischaemic preconditioning during cardiac surgery: systematic review and meta-analysis of perioperative outcomes in randomised clinical trials

Numerous small trials have been conducted to confirm the existence of the ischaemic preconditioning (IP) mechanism in the human heart and to clarify whether it can be induced in a clinical situation. The effect on clinical end-points remains unclear. Most of the available trials reported some clinical outcomes. We performed a systematic review and meta-analysis in order to determine whether IP produces any clinical benefit in cardiac surgery. The systematic review identified 22 eligible trials containing 933 patients. All patients undergoing on-pump surgery also received cardioplegia or intermittent cross-clamp fibrillation (ICCF) with or without adjunctive cooling. IP was mainly performed after initiation of cardiopulmonary bypass, before any additional myocardial protection was initiated. Overall, IP was associated with significant reductions in ventricular arrhythmias (pooled odds ratio 0.11; 95% CI 0.04-0.29; p=0.001), inotrope requirements (pooled odds ratio 0.34; 95% CI 0.17-0.68; p=0.002) and intensive care unit stay (weighted mean difference -3h; 95% CI -4.6 to -1.5h; p=0.001). These effects persisted when the analyses were restricted to those patients receiving cardioplegia. The effect disappeared when the analyses were restricted to patients receiving ICCF. IP may provide additional myocardial protection over cardioplegia alone, but a large-scale clinical trial may be required to determine the role of IP with any certainty.

Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

An increasing number of medical specialists are using fluoroscopy outside imaging departments, but there has been general neglect of radiological protection coverage of fluoroscopy machines used outside imaging departments. Lack of radiological protection training of those working with fluoroscopy outside imaging departments can increase the radiation risk to workers and patients. Procedures such as endovascular aneurysm repair, renal angioplasty, iliac angioplasty, ureteric stent placement, therapeutic endoscopic retrograde cholangio-pancreatography,and bile duct stenting and drainage have the potential to impart skin doses exceeding Gy. Although tissue reactions among patients and workers from fluoroscopy procedures have, to date, only been reported in interventional radiology and cardiology,the level of fluoroscopy use outside imaging departments creates potential for such injuries.A brief account of the health effects of ionising radiation and protection principles is presented in Section 2. Section 3 deals with general aspects of the protection of workers and patients that are common to all, whereas specific aspects are covered in Section 4 for vascular surgery, urology, orthopaedic surgery, obstetrics and gynaecology,gastroenterology and hepatobiliary system, and anaesthetics and pain management.Although sentinel lymph node biopsy involves the use of radio-isotopic methods rather than fluoroscopy, performance of this procedure in operating theatres is covered in this report as it is unlikely that this topic will be addressed in another ICRP publication in coming years. Information on radiation dose levels to patients and workers, and dose management is presented for each speciality.

Remote Ischemic Preconditioning for Renal and Cardiac Protection during Endovascular Aneurysm Repair: A Randomized Controlled Trial

Purpose: To report a randomized clinical trial designed to determine if remote ischemic preconditioning (IP) has the ability to reduce renal and cardiac damage following endovascular aneurysm repair (EVAR). Methods: Forty patients (all men; mean age 76±7 years) with abdominal aortic aneurysms averaging 6.3±0.8 cm in diameter were enrolled in the trial from November 2006 to January 2008. Eighteen patients (mean age 74 years, range 72–81) were randomized to preconditioning and completed the full remote IP protocol; there were no withdrawals. Twenty-two patients (mean age 76 years, range 66–80) were assigned to the control group. Remote IP was induced using sequential lower limb ischemia. Serum and urinary markers of renal and cardiac injury were compared between the groups. Results: Urinary retinol binding protein (RBP) levels increased 10-fold from a median of 235 µmol/L to 2356 µmol/L at 24 hours (p=0.0001). There was a lower increase in the preconditioned group, from 167 µmol/L to 413 µmol/L at 24 hours (p=0.04). The median urinary albumin:creatinine ratio was significantly lower in the preconditioned group at 24 hours (5 versus 8.8, p=0.06). There were no differences in the rates of renal impairment or major adverse cardiac events. Conclusion: Remote preconditioning reduces urinary biomarkers of renal injury in patients undergoing elective EVAR. This small pilot trial was unable to detect an effect on clinical endpoints; further trials are warranted.

Total abdominal hysterectomy versus total laparoscopic hysterectomy for benign disease: a meta-analysis.

Hysterectomy is a very common gynaecological procedure. The vaginal route is considered preferable for hysterectomy, although the ideal route for women unsuitable for the vaginal approach remains unclear. We performed a meta-analysis of published randomised controlled trials to compare outcomes in total abdominal hysterectomy (TAH) and total laparoscopic hysterectomy (TLH) for benign disease. Pooled odds ratios (OR) were calculated for categorical variables using random effects models as per Der Simonian and Laird. Continuous variables were compared by means of weighted mean differences (WMD). TLH is associated with reduced overall peri-operative complications (pooled OR 0.19; 95% CI 0.07-0.50) and reduced estimated blood loss (WMD -183ml; 95% CI -346ml to -21ml; p=0.03). Additionally, there are trends towards shorter hospital stay (WMD -2.5 days; 95% CI -5.1 days to 0.01 days; p=0.05) and post-operative haematoma formation (pooled OR 0.17; 95% CI 0.03-1.01) compared to TAH. The only trade-off appears to be a longer operating time in the TLH group (WMD 22min; 95% CI 5-39min; p=0.01). Rates of major complication were not statistically different (pooled OR 1.35; 95% CI 0.32-5.73) though this analysis is likely underpowered to detect many major complications. As such, TLH appears to offer benefits to women requiring total hysterectomy for benign indications compared to TAH, particularly regarding minor complications, blood loss and hospital stay. However, larger studies are needed to assess the impact on major intra-operative complications and long-term clinical outcomes, particularly pelvic organ prolapse.