Physiological comparison of open and endovascular aneurysm repair

Can HALP score predict post-contrast acute kidney injury and 6-year mortality in patients undergoing endovascular abdominal aneurysm repair?

BACKGROUND

The aim of this study is to investigate the relationship between HALP score and post-contrast acute kidney injury (PC-AKI) and average 6-year mortality in patients undergoing endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

125 patients who underwent EVAR between January 2015 and December 2020 were included in our study. HALP score was calculated with the formula "hemoglobin × albumin × lymphocyte count/platelet count." In the first phase of the study, two groups were developed: those who developed PC-AKI and those who did not. In the second stage, statistical analysis was performed by creating two groups: average 6-year mortality and survivors group.

RESULTS

HALP score was found to be lower in the PC-AKI group [26.12 (14-61.54) versus 40.53 (7.22-103.61); p < .001]. Low HALP score was found to be both a dependent and independent predictor of the development of PC-AKI (p = .019). HALP score was also found to be lower in the mortality group compared to the survivors [28.97 (12.6-103.61) versus 40.81 (7.22-99) p = .004]. Low HALP score was found to be only a dependent predictor of mortality. The development of PC-AKI was found to be an independent predictor of mortality (p = .042).

CONCLUSIONS

The HALP score, which can be calculated with a simple formula, can be used to predict PC-AKI and medium-long-term mortality in EVAR patients.

The effect of Endovascular Aneurysm Repair on Renal Function in Patients Treated for Abdominal Aortic Aneurysm

Aim:

The effect of endovascular aneurysm repair in patients treated for abdominal aortic aneurysm has not been clearly defined. The objective of the present article was to provide a contemporary literature review and perform an analysis to determine the effect of EVAR on renal function in the early post-operative period and during follow-up.

Methods:

A systematic review of the literature was undertaken to identify all studies reporting the effect of EVAR on renal function. Outcome data were pooled and combined overall effect sizes were calculated using fixed or random-effects models.

Results:

Thirty-two studies reporting on 24846 patients were included. Acute renal failure after EVAR occurred with an estimated frequency of 9% (95%CI: 5-16%; I2=97%). Median follow-up period was 19.5 months (range 1-60 months). The estimated frequency of chronic renal failure during follow-up was 7% (95%CI: 3-17%; I2=98%). Hemodialysis was required in 2% (1-3%; I2=97%) of the cases.

Conclusion:

High-level evidence demonstrating the effect of EVAR on the incidence of acute and chronic renal failure is lacking. Based on the current available data, nearly 10% of patients undergoing EVAR for AAA have an increased risk for renal dysfunction after the procedure. Whether this deterioration may lead to a worse outcome has not been adequately proved.

Fascia Suture Technique and Suture-mediated Closure Devices: Systematic Review

Background  The aim of the present study is to review the available data on suture-mediated closure devices (SMCDs) and fascia suture technique (FST), which are alternatives for minimizing the invasiveness of percutaneous endovascular aortic aneurysm repair (p-EVAR) and reduce the complications related to groin dissections. Methods  The Medline, ClinicalTrials.gov, and Cochrane library - Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched for publications regarding SMCD and FST between January 1999 and December 2016. Results  We review 37 original articles, 30 referring to SMCDs (Prostar XL and Proglide), which included 3,992 patients, and 6 articles referring to FST, which include 426 patients. The two techniques are compared only in one article (100 patients). The two types of SMCDs were Prostar and Proglide. In most studies on SMCDs, the reported technical success rates were between 89 and 100%, but the complication rates varied greatly between 0 and 25%. Concerning FST, the technical success rates were also high, ranging between 87 and 99%. However, intraoperative complication rates ranged between 1.2 and 13%, whereas postoperative complication rates varied from 0.9 to 6.2% for the short-term and from 1.9 to 13.6% for the long-term. Conclusions  SMCDs and FST seem to be effective and simple methods for closing common femoral artery (CFA) punctures after p-EVAR. FST can reduce the access closure time and the procedural costs with a quite short learning curve, whereas it can work as a bailout procedure for failed SMCDs suture. The few failures of the SMCDs and FST that may occur due to bleeding or occlusion can easily be managed.

Portsmouth physiological and operative severity score for the Enumeration of Mortality and morbidity scoring system in general surgical practice and identifying risk factors for poor outcome

Background:

Estimation of the outcome is paramount in disease stratification and subsequent management in severely ill surgical patients. Risk scoring helps us quantify the prospects of adverse outcome in a patient. Portsmouth-Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (P-POSSUM) the world over has proved itself as a worthy scoring system and the present study was done to evaluate the feasibility of P-POSSUM as a risk scoring system as a tool in efficacious prediction of mortality and morbidity in our demographic profile.

Materials and Methods:

Validity of P-POSSUM was assessed prospectively in fifty major general surgeries performed at our hospital from May 2011 to October 2012. Data were collected to obtain P-POSSUM score, and statistical analysis was performed.

Results:

Majority (72%) of patients was male and mean age was 40.24 ± 18.6 years. Seventy-eight percentage procedures were emergency laparotomies commonly performed for perforation peritonitis. Mean physiological score was 17.56 ± 7.6, and operative score was 17.76 ± 4.5 (total score = 35.3 ± 10.4). The ratio of observed to expected mortality rate was 0.86 and morbidity rate was 0.78.

Discussion:

P-POSSUM accurately predicted both mortality and morbidity in patients who underwent major surgical procedures in our setup. Thus, it helped us in identifying patients who required preferential attention and aggressive management. Widespread application of this tool can result in better distribution of care among high-risk surgical patients.

Survival of Ruptured Abdominal Aortic Aneurysms in the West of Ireland: Do Prognostic Indicators of Outcome Exist?

Ruptured abdominal aortic aneurysm (RAAA) is a demanding vascular surgical problem and the cause of significant morbidity and mortality. The aim of this study was to identify prognostic factors that influence outcome. Over 6 years, 42 ruptured abdominal aortic aneurysms were operated on with a mean diameter of 7.2 cm. RAAA was defined as free intraperitoneal rupture. Data were collected retrospectively from hospital medical records. The male:female ratio was 8:1 and the mean age was 74 years (range 55–89). Fifteen were in hypovolemic shock and 27 patients were clinically stable. The perioperative mortality rate for the 15 shocked patients was 60% (9 patients) and the 1-year cumulative survival rate was 33%. The perioperative mortality rate for the 27 clinically stable patients was 40% (11 patients) and the 1-year cumulative survival rate was 56%. Survival curves were constructed for these groups to compare male versus female, age =70 versus age <70, shocked versus stable, and preoperative hemoglobin (Hb) =10 vs >10. No patient with preoperative cardiac arrest survived more than 24 hours. With VassarStats, the confidence interval for age, gender, hemodynamic status, and preoperative Hb were calculated. The standard weighted mean analysis by ANOVA gave a p value of <0.001. The overall 30-day mortality rate was 47% (20 of 42) and the 1-year mortality rate was 52% (22 of 42). Male patients over 70 years with RAAA in hypovolemic shock with low Hb have a higher 30-day mortality rate and few survive more than 1 year. The study suggests that each of these 4 parameters separately was not a strong prognostic indicator. Collectively, however, they strongly influence the prognosis of patients with RAAA. These findings strengthen the case for selective treatment for RAAA.

An Update on the Inflammatory Response after Endovascular Repair for Abdominal Aortic Aneurysm

Postimplantation syndrome (PIS) is the clinical and biochemical expression of an inflammatory response following endovascular repair of an aortic aneurysm (EVAR). The goal of this review is to provide an update on the inflammatory response after endovascular repair of abdominal aortic aneurysm, discussing its causes and effects on the clinical outcome of the patient. PIS concerns nearly one-third of patients after EVAR. It is generally a benign condition, although in some patients it may negatively affect outcome. The different definitions and conclusions drawn from several studies reveal that PIS needs to be redefined with standardized diagnostic criteria. The type of the endograft's material seems to play a role in the inflammatory response. Future studies should focus on a better understanding of the underlying pathophysiology, predictors, and risk factors as well as determining whether effective preventive strategies are necessary.

POSSUM: A Scoring System for Perforative Peritonitis

BACKGROUND AND OBJECTIVES

Perforative peritonitis carries considerable morbidity and mortality with the postoperative period unpredictable most of the times. It therefore becomes necessary for a scoring system that predicts the post-operative outcome. POSSUM (Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity) helps in predicting the post-operative morbidity and mortality in these patients. POSSUM scores are based on 12 physiological factors and 6 operative factors. In our study, we included two more factors, which are specifically important in perforative peritonitis; they are, perforation to operation time and the presence of co-morbidity. The presence of these factors significantly affects the post-operative status. Through this prospective study, we can predict which patients are at a higher risk of death or complication and give appropriate management as necessary.

MATERIALS AND METHODS

Our sample size was 50 patients with perforative peritonitis. The study was conducted in single unit from September 2013 to August 2014. Data was collected based on POSSUM scoring system. Outcome of the patients was recorded as death / alive; complicated / uncomplicated and statistical analysis was done by comparing the expected and observed outcomes.

RESULTS

By applying linear analysis, an observed to expected ratio of 1.005 was obtained for mortality and 1.001 for morbidity. There was no statistically significant difference between the observed and expected mortality rates (χ(2) = 3.54, p = 0.316) and morbidity rates (χ(2) = 2.40, p = 0.792). It was found to be comparable with other studies. The factors independently studied; perforation to operation time and presence of co-morbidity were statistically significant with respect to outcome (p<0.05).

CONCLUSION

Although a small sample size is the limitation of this study, POSSUM scoring system is a good indicator of postoperative outcome in patients with perforative peritonitis and was applicable in our setup. It is useful in identifying high risk patients and give preferential care to them for better outcome. Inclusion of factors like perforation to operation time and co-morbid status can improve the scoring system and better care can be provided.

Effects of study design and trends for EVAR versus OSR

Purpose:

To investigate if study design factors such as randomization, multi-center versus single center evidence, institutional surgical volume, and patient selection affect the outcomes for endovascular repair (EVAR) versus open surgical repair (OSR). Finally, we investigate trends over time in EVAR versus OSR outcomes.

Methods:

Search strategies for comparative studies were performed individually for: OVID’s MEDLINE, EMBASE, CINAHL, HAPI, and Evidence Based Medicine (EBM) Reviews (including Cochrane DSR, ACP Journal Club, DARE and CCTR), limited to 1990 and November 2006.

Results:

Identified literature: 84 comparative studies pertaining to 57,645 patients. These include 4 randomized controlled trials (RCTs), plus 2 RCTs with long-term follow-up. The other 78 comparative studies were nonrandomized with 75 reporting perioperative outcomes, of which 16 were multi-center, and 59 single-center studies. Of the single-center studies 31 were low-volume and 28 were high-volume centers. In addition, 5 studies had all patients anatomically eligible for EVAR, and 8 studies included high-risk patients only. Finally, 25 long term observational studies reported outcomes up to 3 years.

Outcomes:

Lower perioperative mortality and rates of complications for EVAR versus OSR varied across study designs and patient populations. EVAR adverse outcomes have decreased in recent times.

Conclusion:

EVAR highlights the problem of performing meta-analysis when the experience evolves over time.

Risk Scoring in Perioperative and Surgical Intensive Care Patients: A Review

PURPOSE

Assessing the risk and predicting the outcome of surgery, trauma, and surgical intensive care is an important aspect of perioperative practice. There have been attempts to devise and validate many scoring systems to predict the prognosis of patients having a similar severity of illness. This article reviews some of the commonly used systems with respect to their development, strengths, and limitations.

SOURCES

Published literature describing risk assessment scores and physiologic scoring systems for preoperative assessment, trauma, and surgical intensive care patients.

PRINCIPAL FINDINGS

Risk scores used in preoperative evaluation assist the clinician in optimizing the patient before, during, and after surgery. Scoring systems applied in intensive care units are useful as guidelines rather than accurate predictors of prognosis for individual patient. Many models are used for audit purposes, and some are used as performance measures and quality indicators of a unit; however, both utilities are controversial because of poor adjustment of these systems to case-mixtures.

CONCLUSIONS

Risk assessment scores may assist in the perioperative risk evaluation with respect to organ systems. Prognostication of critically ill patients belonging to a category of illness may be done using physiological scoring systems taking into account the difference in the case-mix of the particular unit.

A prospective study of subclinical myocardial damage in endovascular versus open repair of infrarenal abdominal aortic aneurysms

BACKGROUND

Endovascular repair of abdominal aortic aneurysms (AAAs) is considered to be less invasive and better tolerated by the cardiovascular system than open repair. Our aim was to assess the true incidence of perioperative myocardial damage associated with endovascular vs open infrarenal AAA repair.

METHODS

Between July 1999 and June 2001, preoperative and postoperative serum troponin T (TnT) levels were measured in all patients presenting for elective AAA repair at Royal Prince Alfred Hospital. The incidence of myocardial damage was recorded on the basis of standard clinical, biochemical, and electrocardiographic changes or a subclinical increase of 50% or more in serum TnT. Patients were excluded if the TnT increase was associated with a significant increase of serum creatinine (> or =50%) with no other evidence of myocardial ischemia. The differences between the two groups were analyzed with the chi 2 test and odds ratios.

RESULTS

A total of 35 open and 112 endovascular AAA repairs were included in the study. There was no significant difference in age, sex, preoperative serum creatinine, or preoperative serum TnT between the two treatment groups. Seventeen patients had biochemical evidence of myocardial damage, which was clinically obvious in only one patient. Even though the incidence of previous myocardial infarction was significantly higher in patients undergoing endovascular repair (41%) than open repair (22%; P < .05), the overall incidence of myocardial damage (clinical or subclinical) was significantly higher in the open group compared with the endovascular group (8 [25%] of 32 vs 9 [8%] of 109, respectively; odds ratio, 3.7; 95% confidence interval, 1.28-10.49; P < .02).

CONCLUSIONS

There is a previously underestimated incidence of subclinical myocardial damage associated with surgery for infrarenal AAA which is lower after endovascular than open repair.

Percutaneous AAA Repair:Is It Safe?

PURPOSE

To assess if percutaneous insertion of large-bore sheaths is safe during endovascular repair (EVR) for abdominal aortic aneurysms (AAA).

METHODS

Ninety-five AAA patients undergoing EVR had the endografts implanted percutaneously via 14-F to 20-F sheaths in a prospective nonrandomized study. Vascular sutures were applied bilaterally to the common femoral arteries using a vascular closure device; the sutures were tied after sheath withdrawal. Blood loss, operative time, and length of stay (LOS) were compared to 26 AAA patients undergoing EVR with bilateral femoral cutdowns before the percutaneous technique was available. Follow-up included duplex ultrasonography and clinical examination.

RESULTS

Bilateral percutaneous closure of the femoral arteries was successful in 78 (82%) patients. Fifteen patients required arteriorrhaphy intraoperatively and 2 others within 24 hours. The failure rate was 20%, 0%, 3%, and 7% for the 20-F, 18-F, 16-F, and 14-F introducers, respectively. Blood loss was 400 mL (range 0-1800) in successful cases, 900 mL (range 0-3000) in failures (p<0.0001). One deep infection at the puncture site required thrombectomy and patchplasty; no other late complication occurred. There was no significant difference in operative time, blood loss, and LOS between patients treated with percutaneous EVR and those with primary femoral exposure.

CONCLUSIONS

Percutaneous transfemoral EVR of AAA using large-bore introducer sheaths is safe. More than three quarters of the patients avoid femoral cutdown. Late complications are rare.

Abdominal aortic aneurysms: elective endovascular repair versus conventional surgery--evaluation with evidence-based medicine techniques

PURPOSE

To use evidence-based techniques to compare elective open surgical repair of abdominal aortic aneurysms with endovascular repair by means of stent placement.

MATERIALS AND METHODS

A focused clinical question formed the basis of a literature search. Evidence-based criteria were used to appraise and assign a "level of evidence" to retrieved articles. The following data were determined from the best studies: systemic, local, and/or vascular complications; graft failure rates; blood loss; mortality; length of intensive care and/or hospital stay; mid- and long-term outcomes; cost of endovascular repair versus that of surgery; and eligibility for endovascular repair. Absolute risk reductions and/or increases and numbers needed to treat or harm were calculated.

RESULTS

The best current evidence came from 22 studies, which showed that there is slight, if any, difference between mortality rates of endovascular repair and surgery. Hospital and/or intensive care stay is shorter, blood loss less, and systemic complications fewer (numbers needed to treat, two to 12) with endovascular repair. Some authors reported a significant increase in local and/or vascular complications with endovascular repair (numbers needed to harm, two to six). Graft failure is significantly more common with endovascular repair (numbers needed to harm, four), and substantive adjunctive interventions are needed. Endovascular repair is more expensive than surgery.

CONCLUSION

Elective endovascular repair has short-term benefits compared with surgery. There is slight, if any, difference in mortality. Endovascular repair costs more than surgery. At follow-up, surgical grafts performed better.

Infrarenal Abdominal Aortic Aneurysms

Screening programs should be instituted to identify patients with small asymptomatic abdominal aortic aneurysms (AAAs) in the community. Screening for AAAs reduces the rate of aneurysm rupture and reduces death from aneurysmal disease in the population. The indications for aneurysm surgery have been defined by two recent randomized clinical trials. Patients with symptomatic or ruptured AAAs should be treated by urgent or emergency surgery. Patients with asymptomatic AAAs should not undergo surgical repair until the aneurysm exceeds 5.4 cm in maximum diameter. The most appropriate surgical option for the majority of patients with AAAs is conventional inlay grafting. This may be approached transperitoneally, although the retroperitoneal approach is favored for inflammatory or juxtarenal aneurysms. Conventional aneurysm repair may be performed with acceptable mortality and good long-term durability in specialized centers with a high volume of cases. The place of endovascular aneurysm repair remains to be defined. Endovascular repair is the best option in high-risk patients with suitable aneurysm morphology. The questions over the long-term durability of endovascular aneurysm surgery in preventing aneurysm rupture make it unsuitable for young patients. Randomized trials will define the indications for this technique. Endovascular surgery is likely to become the most appropriate treatment for ruptured aneurysms in the next decade.

Cytokine activation and intestinal mucosal and renal dysfunction are reduced in endovascular AAA repair compared to surgery

PURPOSE

To compare endovascular (EVR) to open repair (OR) of abdominal aortic aneurysm (AAA) for cytokine activation, changes in the intestinal mucosal barrier, and renal dysfunction.

METHODS

In a prospective nonrandomized study, 15 patients admitted to a university hospital for elective infrarenal AAA repair (8 OR and 7 EVR) were recruited. Intestinal permeability was assessed preoperatively (PO), at day 1 (D1), and at day 3 (D3) after surgery using the lactulose/mannitol differential excretion (LMR) test. Renal damage was assessed from measurements of the urinary albumin:creatinine ratio (ACR); cytokine activation was based on the urinary concentration of tumor necrosis factor receptor p55 (TNF-Rp55) at the same time points. Serum creatinine and urea concentrations were measured preoperatively and daily for 5 days postoperatively.

RESULTS

A significant increase in LMR was found in the OR group at D1 and D3 compared to PO (p<0.05). The LMR increase at D3 was significantly greater in the OR group (p<0.01). A significant difference was observed in the percentage rise in ACR on D1 in the OR group compared to the EVR group (p<0.005). The urinary TNF-Rp55 concentration was significantly elevated in the OR group at D1 (p<0.05) and D3 (p<0.05) compared to baseline; in the EVR group, it was elevated at D1 (p<0.05) compared to PO. The difference was also significant for this marker between the 2 groups at D1 (p<0.01). No significant change was observed in the serum creatinine or urea concentrations in either group perioperatively.

CONCLUSIONS

Endovascular AAA repair is associated with less cytokine production and less intestinal and renal dysfunction compared to the open approach.

Changes in TH1/TH2 immunity after endovascular and conventional infrarenal aortic aneurysm repair: its relevance for clinical practice

OBJECTIVE

to evaluate local surgical trauma induced by endovascular (TPEG) and conventional infrarenal aortic aneurysm repair (AAA-C), the inflammatory response and changes in cell-mediated and antibody-mediated immunity as illustrated by the type-1/type-2 T-helper (TH1/TH2) cell balance were investigated.

DESIGN

prospective study.

PATIENTS AND METHODS

sixteen patients were included, eight patients underwent AAA-C and eight TPEG. Venous peripheral blood samples were collected 24h preoperatively and 24, 48, 72h, 5 and 7 days postoperatively. Besides the WBC, intracellular TH1/TH2 cytokines (IFN-gamma/IL-4) and the cell surface markers HLA-DR on monocytes and CD23 on B cells were measured by four colour flow cytometry.

RESULTS

statistically significant higher values in the AAA-C group were demonstrated for neutrophiles. The TH1/TH2 immunobalance (expressed by forming the ratio of IFN-(gamma/IL-4 producing T cells as well as by the ratio of HLA-DR(pos) monocytes/CD23(pos) B-cells) showed a significant shift towards TH2 immunity in the AAA-C group whereas TPEG led to a significant lesser shift 24-72h after surgery (p < 0.05).

CONCLUSIONS

TPEG leads to a minor distortion of the TH1/TH2 immunobalance. This implies that TPEG is a less stressing procedure, that is especially beneficial in patients whose conditions are considered less suitable for AAA-C due to age and serious comorbidity.

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM)

BACKGROUND AND METHODS

The development of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) is described and its methods of analysis and value in a modern surgical practice are reviewed. A computerized search of all published data in Medline, the Cochrane Library and Embase was made for the last 12 years. Relevant articles were then searched manually for further papers on risk analysis, case-mix comparison and POSSUM methodology.

RESULTS AND CONCLUSION

POSSUM has been evaluated extensively in both general and specialist surgery. While there are problems with both data collection and analysis, when used correctly POSSUM can usefully compare outcomes between surgeons and between hospitals. In specialist surgery, individual regression equations may be needed for each index procedure.

Abdominal aortic aneurysms: cost-effectiveness of elective endovascular and open surgical repair

PURPOSE

To evaluate the cost-effectiveness of elective endovascular and open surgical repair of infrarenal abdominal aortic aneurysms (AAAs) by taking into account short- and long-term outcomes.

MATERIALS AND METHODS

A Markov decision model was developed to evaluate quality-adjusted life-years (QALYs) and lifetime costs of endovascular and open surgical repair. The incremental cost-effectiveness ratio (CER) was calculated for endovascular repair relative to open surgery in a cohort of 70-year-old men with an AAA between 5 and 6 cm in diameter. Clinically effectiveness data were derived from the literature. Cost data were derived from Medicare reimbursement rates, the hospital database, and the literature. One- and multiple-way sensitivity analyses were performed on uncertain model parameters. Costs were converted to year 2000 U.S. dollars; future costs and outcomes were discounted at 3%.

RESULTS

The incremental CER of endovascular repair was 9,905 dollars per QALY. QALYs and lifetime costs were higher for endovascular repair than for open surgery (6.74 vs 6.52 and 39,785 dollars vs 37,606 dollars, respectively). In sensitivity analyses, the incremental CER was insensitive to immediate conversion rate and procedure mortality rate. The incremental CER was sensitive (ie, more than 75,000 dollars per QALY or endovascular repair was ruled out by dominance) to systemic-remote complications, long-term failures, and ruptures.

CONCLUSION

The results suggest that endovascular repair is a cost-effective alternative compared with open surgery for the elective repair of AAA. The benefits and cost-effectiveness are highly dependent on uncertain outcomes, however, particularly long-term failure and rupture rates.

Evaluation of the P-POSSUM mortality prediction algorithm in Australian surgical intensive care unit patients

BACKGROUND

The Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (POSSUM) is an auditing tool designed to compare surgical outcomes independent of case mix. It uses patient physiological and operative data to predict morbidity and mortality for surgical patients. Thus far most evaluations of the POSSUM algorithm and its modifications have emanated from British hospitals. A single-centre retrospective study was therefore performed to determine the applicability of this tool to the Australian surgical case mix.

METHODS

All surgical patients undergoing a surgical procedure admitted to the Royal Brisbane Hospital intensive care facility in 1999 were reviewed retrospectively. Mortality predictions using the Portsmouth modification of the POSSUM algorithm (P--POSSUM) were compared to the actual outcomes using receiver-operator characteristic curve analysis and the Hosmer and Lemeshow Goodness-of-Fit test.

RESULTS

The records of 229 admissions were reviewed. The area under the receiver-operator characteristic curve was 0.68, significantly greater than 0.5 (P = 0.014). Predicted deaths were significantly greater than actual deaths (50 vs 28, P < 0.001), with over-prediction of death rates in all mortality groupings except the two lowest risk deciles.

CONCLUSION

The P-POSSUM algorithm tends to over-estimate mortality in surgical intensive care patients. It may require further calibration before adoption as a surgical audit tool in Australia.

Evaluation of POSSUM in patients with oesophageal cancer undergoing resection

BACKGROUND

The Physiogical and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) has been used to produce a numerical estimate of expected mortality and morbidity after a variety of general surgical procedures. The aim of this study was to evaluate the ability of POSSUM to predict mortality and morbidity in patients undergoing oesophagectomy.

METHODS

POSSUM predictor equations for morbidity and mortality were applied retrospectively to 204 patients who had undergone oesophagectomy for cancer. Observed morbidity and mortality rates were compared with rates predicted by POSSUM using the Hosmer-Lemeshow goodness-of-fit test. Evaluation of the discriminative capability of POSSUM predictor equations was performed using receiver-operator characteristic (ROC) curve analysis.

RESULTS

The observed and predicted mortality rates were 12.7 and 19.1 per cent respectively, and the respective morbidity rates were 53.4 and 62.3 per cent. However, the POSSUM model showed a poor fit with the data both for the observed 30-day mortality (chi2 = 16.26, P = 0.002) and morbidity (chi2 = 63.14, P < 0.001) using the Hosmer-Lemeshow test. ROC curve analysis revealed that POSSUM had poor predictive accuracy both for mortality (area under curve 0.62) and morbidity (area under curve 0.55).

CONCLUSION

These data suggest that POSSUM does not accurately predict mortality and morbidity in patients undergoing oesophagectomy and must be modified.

Elective endovascular versus open surgical repair of abdominal aortic aneurysms: systematic review of short-term results

PURPOSE

To summarize and compare published short-term results of elective endovascular and open surgical repair of abdominal aortic aneurysms.

MATERIALS AND METHODS

A MEDLINE search of the English literature was performed. Studies with at least 10 patients in each treatment group were included if they reported patient characteristics, complications, and mortality. Two reviewers independently extracted the data. A random-effects model was used to pool the data and calculate pooled odds ratios (endovascular vs open surgical repair).

RESULTS

Nine studies were included, reporting results of 1,318 procedures (687 endovascular repair and 631 open surgical repair). Mean blood loss was 456 mL for endovascular repair and 1,202 mL for open surgical repair (P =.003). On average, patients undergoing endovascular repair spent 0.5 days in the intensive care unit and 3.9 days in the hospital, and patients undergoing open surgical repair spent 2.2 days (P =.04) in the intensive care unit and 10.3 days (P =.02) in the hospital. The pooled 30-day-mortality was 0.03 for endovascular repair (95% CI: 0.02, 0.04) and 0.04 for open surgical repair (95% CI: 0.00, 0.07) (P =.03), and the odds ratio was 0.55 (95% CI: 0.33, 0.92). The pooled local and/or vascular complication rate was 0.16 for endovascular repair (95% CI: 0.06, 0.25) and 0.12 for open surgical repair (95% CI: 0.06, 0.18) (P =.46), and the odds ratio was 0.97 (95% CI: 0.62, 1.54). The pooled systemic and/or remote complication rate was 0.17 for endovascular repair (95% CI: 0.09, 0.25) and 0.44 for open surgical repair (95% CI: 0.21, 0.66) (P <.001), and the odds ratio was 0.22 (95% CI: 0.11, 0.45).

CONCLUSION

On the basis of this systematic review, endovascular repair results in less blood loss, shorter intensive care unit and hospital stays, lower 30-day mortality, and lower systemic and/or remote complication rates than those of open surgical repair.

Outcome after endovascular abdominal aortic aneurysm repair: a meta-analysis

PURPOSE

To determine the frequencies of complications and risk factors for complications following endovascular abdominal aortic aneurysm (AAA) repair (EVAR).

METHODS

Thirty-nine articles published between October 1995 and October 1999 in English, German, French, or Dutch were identified in electronic databases. All articles reported perioperative (30-day) complications on 2387 patients, while postoperative complications (>30 days) were reported on 1645 patients in 30 of 39 studies. Data were pooled and subjected to multivariable logistic regression analysis to identify risk factors for death, endoleak, rupture, conversion, and local and systemic complications. Effects of risk factors were expressed as odds ratios (OR) with 95% confidence interval (CI).

RESULTS

Mean follow-up was 13.9 months (range 4-29). The perioperative death rate (3.7%) was lower than postoperative mortality (5.0% per annum). The risks for both endoleak (13.1%) and conversion (5.0%) were higher in the perioperative period than postoperatively (5.4% and 1.4% per annum, respectively). Independent risk factors for perioperative complications were: general anesthesia (death: OR = 5.1, 95% CI 1.9-13.3); EVT graft (endoleak: OR = 3.0, 95% CI 1.3-7.0); female sex (rupture: OR = 2.8, 95% CI 1.4-5.8); hypertension (conversion: OR = 0.03, 95% CI 0.0-0.3); age >70 years (conversion: OR = 3.5, 95% CI 1.3-9.2); and team experience >30 patients (conversion: OR = 3.0, 95% CI 1.2-1.6). Independent risk factors for postoperative complications were: predischarge examination (death: OR = 0.2, 95% CI 0.0-0.7); follow-up 30 days after operation (death: OR = 0.3, 95% CI 0.1-1.0); and female sex (rupture: OR = 1.4, 95% CI 0.5-4.4; conversion: OR 6.8, 95% CI 2.0-23.4; and systemic complications: OR = 2.9, 95% CI 1.1-7.5).

CONCLUSIONS

The risk of complications after EVAR is high, supporting the cautious use of EVAR. Both patient characteristics and procedural variables were independent risk factors for complications. To avoid the limitations of this study, the results of randomized clinical trials must determine if EVAR offers a safe and durable alternative to open AAA repair.

Randomized study comparing cardiac response in endovascular and open abdominal aortic aneurysm repair

BACKGROUND

The aim was to compare the cardiac response and the incidence of adverse cardiac events during and after endovascular (EVAR) and open (OR) repair of abdominal aortic aneurysms (AAAs).

METHODS

Seventy-six patients with an AAA suitable for EVAR, and in a general condition allowing open surgery were randomized to EVAR (57 patients) or OR (19 patients). The analysis was on an intention-to-treat basis. Haemodynamic variables were assessed intraoperatively before, during and after aortic occlusion. During the procedure myocardial ischaemia was identified with use of electrocardiography (ECG) and transoesophageal echocardiography (TEE). After operation, cardiac complications were diagnosed by clinical observation, 12-lead ECG at 1 h, 1 day and 7 days, echocardiography at 1 month and measurement of cardiac enzymes.

RESULTS

After aortic occlusion, a greater decrease in systemic vascular resistance compared with baseline was observed with OR than with EVAR (- 396 and - 70 dyne s/cm5 respectively; P = 0.03). The stroke work index, as a direct measure of myocardial performance, demonstrated a decrease during OR and an increase during EVAR during aortic occlusion (- 6.6 and + 1.7 g m/m2 respectively; P = 0.03) as well as after aortic occlusion (- 7.6 and + 3.4 g m/m2 respectively; P < 0.01), compared with baseline. The incidence of postoperative clinical cardiac complications was comparable in the two study groups; however, myocardial ischaemia, as observed by ECG and TEE, was observed more frequently in the OR group (ten of 19 versus 15 of 57 patients; P = 0.05).

CONCLUSION

Haemodynamic changes were less severe and there was a lower incidence of myocardial ischaemia during EVAR than during OR. Studies are needed to demonstrate whether this may reduce the operative mortality rate.

Portsmouth POSSUM models for abdominal aortic aneurysm surgery

BACKGROUND

The Portsmouth Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (P-POSSUM) equation permits comparative audit that allows for differences in case mix. The methodology has previously been shown accurately to model general surgical and vascular surgical patients. Patients with a ruptured abdominal aortic aneurysm (AAA) are, however, very different from elective patients and it may be hypothesized that they require their own specific risk model.

METHODS

POSSUM data on 444 (213 emergency, 231 elective) admissions for AAA surgery between August 1993 and July 2000 were analysed using the P-POSSUM equation for general surgery and the P-POSSUM equations developed for vascular surgery.

RESULTS

All equations successfully modelled the elective aneurysms but failed to fit the emergency aneurysms, and the elective and emergency aneurysms combined. This suggested that admission method (not a POSSUM data item) is an important factor for patients with AAA. However, with these data it was not possible to generate a model, including admission method, that successfully modelled the combined elective and emergency data. The 213 emergency aneurysm repairs were divided into two groups by operation date. The first 106 (training set) were used to form logistic regression models following the P-POSSUM methodology. These models were found successfully to fit the remaining 107 records (test set) on prospective application (chi2 = 4.50, 4 d.f., P = 0.345).

CONCLUSION

Ruptured AAAs appear to be different from elective AAAs and other vascular cases and require their own risk model.

Establishing an endovascular abdominal aortic program--decisions, decisions, decisions: The London Health Sciences Centre experience

The endovascular repair of abdominal or thoracic aortic aneurysms is an alternative approach to conventional repair in the compromised patient. Although the long-term efficacy of these procedures has yet to be proved, there is growing interest among vascular surgeons and interventional radiologists throughout North America and Europe in the more frequent use of this technique. Starting an endovascular program necessitates extensive cooperation of the interdisciplinary vascular team. Decisions regarding patient selection, equipment, supplies, staff education, and the location of the procedure must be based on sound principles. This article demonstrates how a program can be planned, implemented, and evaluated by the use of a "decision tree." The experience of the London Health Sciences Centre will be used as a benchmark in the discussion of relative merits of branch points in program development. The article gives persons contemplating a program a structured process in decision making to avoid potential pitfalls.

Early inflammatory response after elective abdominal aortic aneurysm repair: a comparison between endovascular procedure and conventional surgery

OBJECTIVE

To determine the nature of and to compare the inflammatory responses induced by (1) endovascular and (2) conventional abdominal aortic aneurysm (AAA) repair.

MATERIAL AND METHODS

Twelve consecutive patients undergoing elective infrarenal AAA repair were prospectively studied. Seven patients were selected for endovascular procedures (the EAAA group); five patients underwent open surgery (the OAAA group). Three control patients undergoing carotid thromboendarterectomy were also included. Serial peripheral venous blood samples were collected preoperatively, immediately after declamping or placement of the endograft, and at hours 1, 3, 6, 12, 24, 48, and 72. Acute phase response expression of peripheral T lymphocyte and monocyte activation markers and adhesion molecules (flow cytometry), soluble levels of cell adhesion molecules (enzyme-linked immunosorbent assay), cytokine (tumor necrosis factor alpha, interleukin-6, and interleukin-8) release (enzyme-linked immunosorbent assay), and liberation of complement products (nephelometry) were measured.

RESULTS

Regarding acute phase response, the EAAA and OAAA groups showed significant increases in C-reactive protein (P <.001 and P =.001), body temperature (P =.035 and P =.048), and leukocyte count (P <.001 and P <.001). Similar time course patterns were observed with respect to body temperature (P =.372). Statistically significant different patterns were demonstrated for C-reactive protein (P =.032) and leukocyte count (P =.002). Regarding leukocyte activation, a significant upregulation of peripheral T lymphocyte CD38 expression was observed in the OAAA group only (P =.001). Analysis of markers such as CD69, CD40L, CD25, and CD54 revealed no perioperative fluctuations in any group. Regarding circulating cell adhesion molecules, the EAAA and OAAA groups displayed significant increases in soluble intercellular adhesion molecule-1 (P =.003 and P =.001); there was no intergroup difference (P =.193). All groups demonstrated high soluble von Willebrand factor levels (P =.018, P =. 007, and P =.027), there being no differences in the patterns (P =. 772). Otherwise, soluble vascular cell adhesion molecule-1, soluble E-selectin, and soluble P-selectin did not appear to vary in any group. Regarding cytokine release, although a tendency toward high tumor necrosis factor alpha and interleukin-8 levels was noticed in the EAAA group, global time course effects failed to reach statistical significance (P =.543 and P =.080). In contrast, interleukin-6 showed elevations in all groups (P =.058, P <.001, and P =.004). Time course patterns did not differ between the EAAA and OAAA groups (P =.840). Regarding complement activation, the C3d/C3 ratio disclosed significant postoperative elevations in the EAAA and OAAA groups (P =.013 and P =.009). This complement product release was reduced in the EAAA group (P <.001).

CONCLUSIONS

The current study indicated that both endovascular and coventional AAA repair induced significant inflammatory responses. Our findings showed that there were no large differences between the procedures with respect to circulating cell adhesion molecule and cytokine release. Moreover, the endoluminal approach produced a limited response in terms of acute phase reaction, T lymphocyte activation, and complement product liberation. This might support the concept that endovascular AAA repair represents an attractive alternative to open surgery. Given the relatively small sample size, further larger studies are required for confirmation of our observations.