Can We Better Differentiate Type A Dissections: Evaluating the Role of Aortic Ratios.

OBJECTIVES: Type A aortic dissection (ATAAD) is hypothesised as a progression of aneurysmal dilation, but 60% of patients in the International Registry of Acute Aortic Dissection (iRAD) registry had a maximum aortic diameter (MAD)<55 mm. We aim to demonstrate that size ratios and aortic wall stress, assessed using a simplified markers, are unique to aortic patients who have had adverse events (ATAAD) compared to those who have not (thoracic aortic aneurysm [TAA]). METHODS: A retrospective cohort analysis of patients who underwent aortic intervention at Waikato Hospital, New Zealand between 2015-2020, comparing dissection (ATAAD) to TAA patients. MAD; ratio of MAD to standardised-points within the aorta; and MAD-to-height collected from computed tomography (CT)-scans of all patients was undertaken. Receiver operating characteristic (ROC)-analysis to determine cut-off point for each marker was undertaken together with multivariable logistic regression comparing both cohorts, cross-validated by propensity-score matched analysis. RESULTS: Cohort of 215 patients, 78 (36.3%) ATAAD and 137 (63.7%) TAA; median age at intervention 63.3 years, 52 (24.2%) females, both cohorts matched for size. Using the entire cohort, the MAD: sinus of Valsalva (SoV) ratio>1.06 (cut-off value) had 4.5-times greater association with ATAAD (95%CI 1.46-13.8) and a 0.1-unit increased conferred 1.45-times greater association with ATAAD (95%CI 1.00-2.08). MAD>55 mm only seen in 33.3% of ATAAD (n=26/78), and not associated with ATAAD (OR 1.88, 95%CI 0.64-5.51). Compared to MAD, MAD:SoV ratio had greater sensitivity (33% vs 73%), lower number-needed-to-treat (17.9 vs 2.7) and superior discrimination (area under the curve [AUC] 0.54 vs 0.71). Findings were consistent with propensity score matched analysis. CONCLUSIONS: MAD:SoV ratio significantly correlates with ATAAD (4.5 times), with superior sensitivity, discrimination, and attributable-risk-percentage compared to MAD alone.

Preoperative Neutrophil and Lymphocyte Ratio as a Predictor of Mortality and Morbidity After Cardiac Surgery.

BACKGROUND: Inflammatory markers, such as neutrophils and lymphocytes, for risk stratification of postoperative morbidity and mortality in patients with cardiovascular disease may provide benefit for patient selection for cardiac surgery. This study aimed to investigate the association between preoperative neutrophil to leucocyte ratio (NLR) after cardiac surgery. METHODS: A retrospective study from September 2014 to November 2017 undergoing cardiac surgery at Waikato Hospital was conducted. Preoperative haematological profiles, patient factors and primary and secondary endpoints were obtained. The primary endpoint was 30-day new postoperative atrial fibrillation requiring treatment, new neurological insult, readmission within 30 days and 30-day mortality. The secondary endpoint was long-term all cause mortality. RESULTS: Of the 1,694 patients included in the study, 21% (356/1,694) of patients had new atrial fibrillation (AF), 3.0% (51/1,694) strokes, 10.6% (180/1,694) readmissions and 2.8% (47/1,694) deaths within 30 days were observed. Receiver operator curve (ROC) returned a cut-off value of NLR equal to or greater than 3.23 (high NLR) to be associated with greatest mortality. Subsequently, a high NLR was compared to the endpoints. High NLR was associated with higher postoperative (p<0.001) and discharge creatinine, longer ICU stay (p=0.012), prolonged intubation and ventilation (p<0.001), new neurological status (p=0.002) and increased risk of returning to theatre (p=0.009). After logistic regression, high NLR was associated with increased mortality (OR 3.36, p=0.001). CONCLUSIONS: The interpretation and utilisation of readily available haematological markers can provide further risk stratification data to the surgeon when considering the postoperative cardiac surgery risks.

Performance of the AusSCORE II and STS Score for Coronary Artery Bypass Grafting in a New Zealand Population.

BACKGROUND: The updated Australian System for Cardiac Operative Risk Evaluation (AusSCORE II) and the Society of Thoracic Surgeons (STS) Score are well-established tools in cardiac surgery for estimating operative mortality risk. No validation analysis of both risk models has been undertaken for a contemporary New Zealand population undergoing isolated coronary bypass surgery. We therefore aimed to assess the efficacy of these models in predicting mortality for New Zealand patients receiving isolated coronary artery bypass grafting (CABG). MATERIAL AND METHODS: A prospective database was maintained of patients undergoing isolated CABG at a major tertiary referral centre in New Zealand between September 2014 and September 2017. This database collected the patients' demographic, clinical, biochemical, operative and mortality data. The primary outcome measure was the correlation between the predicted AusSCORE II and STS Score mortality risks and the observed 30-day mortality events for all patients in the database using discrimination and calibration statistics. Discrimination and calibration were assessed using receiver operating characteristic (ROC) curves and the Hosmer-Lemeshow test respectively. RESULTS: A total of 933 patients underwent isolated CABG during the 3-year study period. There were seven deaths in the study cohort occurring within 30 days of surgery. Discrimination analysis demonstrated the area under the ROC curve (AUC) of the AusSCORE II and STS Score as 88.2% (95% CI: 85.9-90.2, p<0.0001) and 92.1% (95% CI: 90.2-93.7, p<0.0001) respectively. Calibration analysis revealed Hosmer-Lemeshow test p-values for the AusSCORE II and STS Score as 0.696 and 0.294 respectively. DISCUSSION: ROC curve analysis produced very high and statistically significant AUC values for the AusSCORE II and STS Score. Hosmer-Lemeshow test analysis revealed that both risk scoring tools are well calibrated for our study cohort. Therefore, the AusSCORE II and STS Score are both strongly predictive of 30-day mortality for isolated coronary artery bypass grafting surgery in our New Zealand patient population. Both risk models have performed with excellent discrimination and calibration. There is, however, a need to consider the performance of these risk stratification models in other cardiac surgical procedures outside isolated coronary bypass surgery where appropriate.

Assessment of the EuroSCORE II in a New Zealand Tertiary Centre.

BACKGROUND: The updated European System for Cardiac Operative Risk Evaluation (EuroSCORE II) is a well-established cardiac surgery risk scoring tool for estimating operative mortality. This risk stratification system was derived from a predominantly European patient cohort. No validation analysis of this risk model has been undertaken for the New Zealand population across all major cardiac surgery procedures. We aim to assess the efficacy (discrimination and calibration) of the EuroSCORE II for predicting mortality in cardiac surgical patients at a large New Zealand tertiary centre. METHODS: Data was prospectively collected on patients undergoing cardiac surgery from September 2014 to September 2017 at Waikato Hospital, New Zealand. Patient demographic information, preoperative clinical risk factors and outcome data were entered into a national database. Included patients received either isolated coronary artery bypass grafting (CABG), isolated valve surgery, isolated thoracic aortic surgery, or a combination of these procedures. The primary outcome was the discrimination and calibration of predicted EuroSCORE II risk scores compared with observed 30-day mortality events. RESULTS: 1,666 cardiac surgery patients were included during the study period, with an average EuroSCORE II of 2.97% (95% confidence interval (CI): 2.76-3.18). Nine hundred thirty-three (933) patients underwent isolated CABG, 384 underwent isolated valve surgery, 48 received isolated thoracic aortic surgery and 301 received combination procedures. Thirty-day (30-day) mortality events in each of these groups was 7, 4, 2 and 13 deaths respectively. There were 26 deaths across the total cohort at 30-days (observed mortality rate 1.56%). Discrimination analysis using receiver operating characteristic curves demonstrated the area under the curve (AUC) of the EuroSCORE II in each of these groups as 93.4% (95% CI: 91.6-94.9, p<0.0001), 66.3% (95% CI: 61.3-71.0, p=0.37), 37.0% (95% CI: 15.7-58.2, p=0.23) and 74.8% (95% CI: 69.5-79.6, p<0.0001) respectively. The total cohort AUC was 83.1% (95% CI: 81.2-84.9, p<0.0001). Calibration analysis using Hosmer-Lemeshow tests for the subgroups revealed p-values of 0.848, 0.114, 0.638 and 0.2 respectively. The total cohort Hosmer-Lemeshow p-value was 0.317. CONCLUSIONS: EuroSCORE II showed a strong discriminative ability for isolated CABG 30-day mortality in a New Zealand patient cohort. However, the scoring system discriminated poorly across valvular, thoracic aortic or complex combination cardiac surgical procedures. Good calibration of the EuroSCORE II was achieved across both the total cohort and subgroups. It is important to consider the performance of other cardiac surgery risk stratification models for the New Zealand population.

Early Discharge From Intensive Care After Cardiac Surgery is Feasible With an Adequate Fast Track, Stepdown Unit: Waikato Experience.

BACKGROUND: Enhanced recovery programs within cardiothoracic surgery are a well described benefit to patient postoperative outcomes. We describe our Australasian unit's experience of a day zero discharge enhanced recovery unit from the intensive care department. METHODS: A retrospective study was conducted on a prospectively maintained database at Waikato Cardiothoracic Unit from September 2014 till October 2017 with 1,739 patients undergoing cardiac surgery. Twenty-two (22) patients were excluded as deaths either intraoperative or in the intensive care unit (ICU) and therefore never discharged. Total population of the study was 1,717 patients. The primary endpoint of this study was to determine if there is no survival disadvantage for the day zero discharge unit compared to standard treatment in ICU at follow-up. The secondary endpoint of the study was to highlight the association between pre and postoperative variables and the impact on discharge from the ICU. RESULTS: One hundred sixty-eight (168) patients were discharged to the enhanced recovery unit (ERU) day zero. Mean number of hours spent in ICU for the day zero cohort was 7.18 (±1.59. Mean Age 62.5 (±11.22), M:F 4.25:1. Patients were more likely to be discharged day zero if they had a lower EuroSCORE II 1.57 (±1.67) and lower preoperative creatinine 89.4 (±27.5). Those admitted to the ERU on day zero postoperatively were more likely to be discharged with a lower creatinine level, a higher haemoglobin level and have less readmissions per 30days (p<0.05). Survival analysis demonstrated that the patients who were discharged early from ICU had significantly better follow-up survival compared to those who were discharged after 24hours (p<0.05). CONCLUSIONS: A fast track unit increases the efficiency of an ICU and cardiac surgical department. With the advancements of cardiac surgery a higher number of patients will be suitable for a fast track method. Our unit has demonstrated that a day zero fast track unit in New Zealand can perform with adequate patient safety with no increased risk of mortality and with low rates of failure of the day zero discharge fast track therapy.

Early diagnosis of surgically curable lung cancer is commonly serendipitous.

AIMS: Lung cancer is the largest cause of cancer death in New Zealand, accounting for 18.3% of cancer-related deaths.[[1,2]] There is limited literature on how patients with lung cancer clinically present in New Zealand. The aim of this cohort study was to identify the rate of incidentally diagnosed lung cancer in the Midland Region, the common symptomatology and route of diagnosis. METHODS: This retrospective cohort study included patients with lung cancer who underwent potentially curative thoracic surgery between January 2011 to June 2018 at Waikato Hospital, New Zealand. Symptoms or signs recorded were cough, dyspnoea, haemoptysis, lymphadenopathy, chest pain, hoarseness, fatigue, weight loss and finger clubbing. The lung cancer cases were grouped into incidental finding, symptomatic general practitioner, symptomatic emergency department and surveillance. RESULTS: Three hundred and ten patients with lung cancer had thoracic surgery with curative intent at Waikato Hospital. Two hundred and fourteen (69%) patients had symptoms which prompted presentation to a treating physician and 96 (31%) patients were asymptomatic. Incidental diagnosis was demonstrated in 121 (39.4%) patients. Of the patients diagnosed incidentally, 36.4% (n=44) had symptoms of lung cancer with the main symptoms including 45% with cough (n=20), 28% with dyspnoea (n=12) and 28% chest pain (n=12). CONCLUSIONS: In New Zealand, a large amount of lung cancer is still diagnosed incidentally with symptoms of cough, dyspnoea and chest pain. Further research into the development of a lung cancer screening program in New Zealand for a high-risk population is warranted.

Cardiac surgery simulation: a low-cost feasible option in an Australasian setting.

BACKGROUND: Simulation training is a useful adjunct to surgical training and education (SET) in Cardiothoracic Surgery yet training opportunities outside the Royal Australasian College of Surgery or industry-sponsored workshops are rare due to high cost and limited training faculty, time, assessment tools or structured curricula. We describe our experience in establishing a low-cost cardiac simulation programme. METHODS: We created low-cost models using hospital facilities, hardware stores, abattoirs and donations from industry. Three workshops were conducted on coronary anastomoses, aortic and mitral valve replacement. RESULTS: Whole porcine hearts were sourced from local farms. Industry donations of obsolete stock were used for suture and valve material-stations constructed using ironing-board, 2-L buckets and kebab-skewers. Suture ring holders were fashioned from recycled cardboard or donated. All participants were asked to complete pre and post simulation self-assessment forms. Across three workshops, 45 participants (57.8% female) with a median age 27 (interquartile range 24-31) attended. Training level consisted of nurses (8, 17.8%), medical students (17, 37.8%), residents/house officers (6, 13.3%) and registrars (14, 31.1%). There were improvements in knowledge of anatomy (mean difference 18%; 95% confidence interval 12%-24%), imaging (16%; 10%-22%) and procedural components (34%; 28%-42%); and practical ability to describe steps (30%; 24%-38%), partially (32%; 26%-38%) or fully complete (32%; 28%-38%) the procedure. CONCLUSIONS: Simulation-based training in cardiac surgery is feasible in a hospital setting with low overhead costs. It can benefit participants at all training levels and has the potential to be implemented in training hospitals as an adjunct to the SET programme.

A prospective five-year cohort study of undiagnosed sleep apnea in patients undergoing coronary artery bypass graft surgery.

BACKGROUND: We aimed to study prospectively the nature and effect of sleep apnea-hypopnea syndrome (SAHS) in patients undergoing coronary artery bypass graft (CABG) surgery over five years of follow-up. METHODS: Patients undergoing CABG surgery (N.=145) were assessed longitudinally (baseline, 1 year, and 5 years post-surgery) using the 'STOP-BANG' screen of sleep apnea risk. Additionally, all patients had a preoperative multiple-channel sleep-study, providing acceptable data for an obstructive and central apnea, and desaturation index in 97 patients. RESULTS: Preoperatively, over half (63%) of patients obtained an apnea-hypopnea index score (combining apnea types) in the moderate-severe range for SAHS, and STOP-BANG threshold score (>3/8) was reached by most (95%) patients. Despite some improvement in 'STOP symptoms' at 1-year follow-up, most patients (98%) remained at risk of SAHS at 5 years post-surgery. There was an underlying and chronic relationship between STOP-BANG score and cardiac symptoms at both baseline and 5-year follow-up. Additionally, SAHS variables were associated with greater incidence of acute postoperative events, and generally with increased length of stay on the intensive care unit. CONCLUSIONS: We confirm that SAHS is common in CABG-surgery patients, presenting additional clinical challenges and cost implications. The underlying pathophysiology is complex, including upper airway obstruction and cardiorespiratory changes of heart failure. In patients presenting for CABG-surgery, we show chronic susceptibility to SAHS, likely associated with traditional risk factors e.g. obesity but perhaps also with gradual decline in heart function itself. Superimposed on this, there is potential for exacerbated risk of morbidity at the time of CABG surgery itself.

Does the use of an in situ or Y-configuration for bilateral internal thoracic arteries influence long-term survival, patency or repeat revascularization in coronary bypass surgery?

A best evidence topic was constructed according to a structured protocol. The question addressed was whether the configuration of bilateral internal thoracic arteries (BITAs) influences survival, patency or repeat revascularization in patients undergoing coronary artery bypass grafting. Five hundred and seventy-one papers were found using the reported searches, of which 8 represented the best evidence to answer the clinical question. One systematic review, 4 randomized trials and 3 observational studies were selected. The authors, date, journal, study type, population, main outcome measures and results are tabulated. All 4 prospective randomized trials found no significant difference in graft patency or mortality when comparing Y-graft and in situ configurations. Three of the 4 randomized trials found no difference in major adverse cardiovascular and cerebrovascular events or repeat revascularization at follow-up. An exception was Glineur et al. (Bilateral internal thoracic artery configuration for coronary artery bypass surgery: a prospective randomized trial. Circ Cardiovasc Interv 2016;9:7), who found that the Y-configuration resulted in lower rates of major adverse cardiovascular and cerebrovascular events. All 3 observational studies reviewed found no alteration in survival, cardiac events or repeat revascularization between in situ and Y-graft BITA configurations. One systematic review found similar outcomes with respect to mortality, cardiac events and repeat revascularization with in situ and composite BITA. In summary, existing literature demonstrates no difference in clinical outcomes between composite and in situ graft configurations. Furthermore, the configuration of BITA does not affect mortality, graft patency or repeat revascularization.

Complex coarctation of the aorta requiring a third redo operation.

Coarctation of the aorta can require multiple redo surgeries. It is extremely pertinent to plan for this and ensure that each operation is performed with future repair in mind. We present a rare case and the subsequent management of competitive flow in coarctation of the aorta requiring a fourth operation for repair.

Role of the femorofemoral crossover graft in acute lower limb ischemia due to acute type B aortic dissection.

Acute limb ischemia due to type B aortic dissection is rare and continues to be a management challenge. A case series is presented here with the aim of assessing the outcomes of treatment with a femorofemoral crossover graft with or without thoracic stent graft insertion. This is a combined retrospective and prospective review of nine cases of acute lower limb ischemia secondary to acute type B aortic dissection. The presenting features, radiological findings, treatment and outcomes were reviewed. Five patients had a femorofemoral crossover graft (FFXO) alone, two an FFXO with a thoracic stent graft and the eighth a thoracic and iliac stent. The other case was initially treated conservatively but subsequently required an FFXO. The mean follow-up was 16 (3-51) months. A further two thoracic stents were placed during the follow-up period. Thus five out of nine patients (56%) required aortic stenting. This series suggests that an FFXO is a reliable treatment for acute limb ischemia due to type B aortic dissection. However, these patients are often complex with ischemia in other vascular beds and are at risk of subsequent aneurysmal dilation.

Infected calcified homograft root: a sutureless solution.

Aortic valve reoperation after homograft root implantation is high risk and may be technically challenging. Dense calcification of the annulus may prevent suture placement and often necessitates impromptu high-risk redo root replacement. Although transcutaneous aortic valve implantation is an attractive option in such scenarios, in the context of endocarditis it is contraindicated. We describe a novel approach to aortic valve replacement in a patient with infective endocarditis of a heavily calcified homograft root, using a sutureless valve. This approach successfully avoided the need for redo root replacement with its attendant risks.

Does muscle-sparing thoracotomy as opposed to posterolateral thoracotomy result in better recovery?

A best evidence topic was written according to a structured protocol. The question addressed was whether muscle-sparing thoracotomy (MST), as opposed to posterolateral thoracotomy (PLT), results in better recovery. A total of 108 papers were found using the reported searches of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. A recent large prospective, randomized, double-blinded, controlled study demonstrated a shorter length of stay in patients undergoing MST. It failed to demonstrate any significant difference in pain reported or pulmonary function. A separate prospective randomized controlled trial focussed on pain, pulmonary function, late shoulder range of motion and late muscle strength. It failed to show any significant difference in these domains between PLT and MST. While the mean 'opening time' is greater when performing a MST, this is negated by a shorter mean 'closing time' when compared with PLT. Overall, the evidence suggests that MST results in greater early (1 week) preservation of skeletal muscle strength and range of motion over PLT. This difference has disappeared at 1 month. There is little evidence to suggest a difference in pulmonary function or pain dependent on the thoracotomy type. Moreover, analgesic consumption is similar. However, there is an inverse relationship between the incision length and the post-thoracotomy syndrome.

Does surgery improve prognosis in patients with small-cell lung carcinoma?

A best evidence topic was written according to a structured protocol, asking 'does surgery improve prognosis in patients with small-cell lung carcinoma (SCLC)?' One hundred and thirteen papers were identified, of which the nine papers best able to answer the question were selected and the details of each tabulated. The prohibitive attitude of clinicians toward surgery in SCLC has prevailed since the 1960s, informed by a prospective randomized trial in which 144 patients were assigned to surgical treatment or to radical radiotherapy. Surgery conferred no survival benefit when compared with radical radiotherapy as assessed at 6 monthly intervals up to 10 years post-treatment. Patients with metastatic disease were excluded; however, diagnostic advances subsequent to these trials justify a re-evaluation of the issue, given the greater degree of accuracy with which sub-groups of patients who might benefit from surgery can now be defined. Only one further prospective, randomized trial features in the literature. This study also discerned that no survival benefit was accrued by adding surgery to chemotherapy. However, this study only included patients who responded to an initial course of chemotherapy and also excluded patients with peripheral nodules only. Subsequent investigators have asserted the value of surgery in SCLC. A retrospective case-control study found that surgery significantly improved median survival in patients with stage I disease when compared with patients undergoing medical therapy. One British centre reported survival rates of 52% at 5 years amongst patients undergoing resection and nodal dissection for stage II-IIIA disease. In a retrospective analysis of the Norwegian cancer database, 5-year survival for patients with stage I undergoing surgery was 44.9%, as opposed to 11.3% amongst those treated medically. This finding was echoed in the analysis of the surveillance epidemiology and end results database in the USA, which found improved median survival amongst patients undergoing surgery for limited SCLC. Prospective studies of carefully selected patients have documented good median survival in patients whose tumour was completely resected. We conclude that surgery for early-stage SCLC improves prognosis as part of a multi-modality approach. This echoes the advice of the 2011 national institute of health and clinical excellence guidelines regarding surgery in SCLC.

Does posterior pericardiotomy reduce the incidence of atrial fibrillation after coronary artery bypass grafting surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether posterior pericardiotomy (PP) reduces the incidence of atrial fibrillation (AF) after coronary artery bypass grafting surgery. Twelve papers were found using the reported search, of which seven represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. One non-randomized prospective cohort controlled study generated early evidence that PP reduced the rate of postoperative AF and pericardial effusion. The operative details of PP were clearly explained in this paper. The efficacy of this procedure was subsequently examined in five prospective randomized controlled trials performed with some limitations, listed in the table. Meta-analysis of the randomized control trials examined a group of 763 patients (PP = 389, control = 374). It revealed a highly significant reduction in total arrhythmias and AF in the PP group (odds ratio 0.31 and 0.33, respectively). There was a 10.8% AF rate in the PP group (41/379) and a 28.1% AF rate in the control group (108/384). Furthermore, the PP group had a significant reduction in the rate of early and late pericardial effusion (P < 0.001). Moreover, the reduction in the incidence of arrhythmias was significantly associated with the reduction in the incidence of pericardial effusion. Referring to these studies, two guidelines recommend PP to reduce postoperative AF with grade B strength of recommendation. We conclude that PP significantly reduces the incidence of postoperative AF. The number needed to treat to prevent one case of AF is six.

Does video-assisted mediastinoscopy have a better lymph node yield and safety profile than conventional mediastinoscopy?

A best evidence topic was written according to a structured protocol. The question addressed was whether video-assisted mediastinoscopy (VAM) has a better lymph node yield and safety profile than the conventional mediastinoscopy (CM). A total of 194 papers were found, using the reported searches, of which five represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Two studies to date have directly compared CM and VAM with respect to lymph node yield, calculated diagnostics performance and complication rate. In both of these, lymph node yield is shown to be higher using VAM with better sensitivity, negative predictive value and accuracy rates. The favourable figures of lymph node sampling are found to be statistically significant in the single study providing such analysis. Complication rates using VAM are low, however, in the one instance where it is reported as higher than CM, the extensive lymph node dissection used in this technique may be a reasonable explanation for this finding. All studies described here exemplify VAM as a safe and useful tool in mediastinal staging, lymph node dissection and tissue diagnosis of mediastinal diseases given its superior visualization of surrounding structures and advantage of bimanual dissection. The future scope for diagnostic and therapeutic indications of cervical mediastinscopy is anticipated with recent advances and new techniques, such as video-assisted mediastinoscopic lymphadenectomy and virtual mediastinscopy.

What is the role of screening in the management of abdominal aortic aneurysms?

A best-evidence topic in vascular surgery was written according to a structured protocol. The question addressed was whether screening asymptomatic individuals for an abdominal aortic aneurysm (AAA) is feasible and improves disease-free survival. Seven studies presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and limitations of the studies are tabulated. In total, four randomized population-based studies have evaluated ultrasound screening for AAA: two British studies, Multicentre Aneurysm Screening Study (MASS) and the Chichester trial, and one each in Viborg County, Denmark and Western Australia. Participants were randomized to receive an invitation to screen or not. The MASS trial randomized 67 770 men, followed participants over 10 years and concluded that screening would almost half AAA-related deaths in men aged 65-74 years. The smaller Chichester trial included only 6040 men but demonstrated a 42% reduction in AAA-related mortality at 5 years, with ongoing benefit at 15 years (11% reduction). The Viborg County trial recruited 12 639 men aged 64-73 years, showed a 66% reduction in AAA-related mortality over 14 years. Finally, the Western Australia trial evaluated 41 000 men but included an older population of 65-83 years old. No benefit was seen in this age group but subgroup analysis of men aged 65-74 showed a significant mortality benefit. Only a small or insignificant benefit in all-cause mortality was seen in any of these studies. A recent meta-analysis of these trials has shown a significant benefit in AAA-related mortality in the long term and concluded that AAA screening is superior to other established screening programmes. The cost-effectiveness of screening was assessed in the MASS and Viborg County trials and was found to be substantially below the cost threshold set by the National Institute of Clinical Excellence for acceptance of interventions. Quality of life was assessed in the MASS and in a case-control study and showed no adverse effects that outweigh the benefits. We concluded that ultrasound screening for AAAs has met all the criteria to become a screening programme and would substantially reduce disease-related death with no adverse effect on quality of life.