Anthony J. Salvian

Predictors of death in nonruptured and ruptured abdominal aortic aneurysms

PURPOSE This study evaluated perioperative variables to predict death in nonruptured and ruptured abdominal aortic aneurysm (AAA) surgery. METHODS A consecutive review of all patients who underwent AAA surgery from January 1984 to December 1993 was carried out. Perioperative variables were analyzed with univariate and multivariate statistical models to predict mortality rates. RESULTS Four hundred seventy-eight patients with nonruptured AAAs and 157 patients with ruptured AAAs were studied. In patients with nonruptured AAAs, the mortality rate was 3.8%. Using stepwise logistic regression analysis, independent predictors of death were perioperative myocardial infarction (odds ratio [OR], 5.0; p < 0.01), prolonged postoperative ventilation (OR, 4.0; p < 0.01), history of peripheral vascular disease (OR, 2.9; p < 0.01), preoperative renal dysfunction (OR, 2.7; p < 0.01), and history of congestive heart failure (OR, 2.6; p < 0.03). In patients with ruptured AAAs, the mortality rate was 46%. Analysis of preoperative variables using multivariate stepwise logistic regression found predictors of death to be preoperative unconsciousness (OR, 3.1; p < 0.01), advanced age (OR, 1.9; p < 0.01), and cardiac arrest (OR, 1.8; p < 0.05). In patients who survived the initial surgery for ruptured AAA, a second stepwise logistic regression model found independent predictors for subsequent postoperative death to be coagulation disorder (OR, 7.9; p < 0.01), ischemic colitis (OR, 6.4; p < 0.01), inotropic support beyond 48 hours (OR, 4.8; p < 0.01), delayed transport to operating room (OR, 4.6; p < 0.01), advanced age (OR, 4.4; p < 0.01), perioperative myocardial infarction (OR, 4.0; p < 0.05) and postoperative renal dysfunction (OR, 3.7; p < 0.01). CONCLUSION Prolonged ventilation, perioperative myocardial infarction, a history of peripheral vascular disease, preoperative renal dysfunction, and a history of congestive heart failure are independent predictors of perioperative death in patients with nonruptured AAAs. For patients with ruptured AAAs, mortality rates can be estimated before surgery using age, level of consciousness, and cardiac arrest. For patients who survive the initial surgery for ruptured AAA, subsequent mortality rates can also be predicted.

Selective shunting with EEG monitoring is safer than routine shunting for carotid endarterectomy

The purpose of this study was to identify whether EEG is an adequate method of monitoring cerebral perfusion during carotid endarterectomy and of determining the need for use of an indwelling shunt. A retrospective review of 305 carotid endarterectomies comparing the results of routinely shunted patients with patients selectively shunted based on EEG monitoring, was carried out. Of the carotid endarterectomies, 92 (30%) were routinely shunted and 213 (70%) were selectively shunted. In the selectively shunted group, 34 (16%) subsequently required shunting. The major stroke rate in the routinely shunted group was 4.4% ((4) cases) and in the selectively shunted group was 0.5% ((1) stroke). Three of the four major strokes in the routinely shunted group were embolic in origin and one was caused by acute thrombosis. The only major stroke in the selectively shunted group was from intracerebral hemorrhage. In conclusion EEG monitoring is a safe and reliable method to determine the need for shunting during carotid endarterectomy. Routine non-selective use of a shunt may increase the risk of perioperative stroke from arterial injury and associated thromboembolism.

Carotid endarterectomy in octogenerians

PURPOSE The purpose of this study was to determine the safety and efficacy of carotid endarterectomy (CEA) in octogenerians. METHODS The records of 59 CEA performed in 57 patients who were 80yr or older between April 1993 and September 1998 were reviewed. There were 33 males and 24 females with a mean age of 82. Forty-nine procedures (83%) were performed for symptomatic carotid stenosis. The perioperative mortality and morbidity including neurological events were recorded. Long term follow-up data was also obtained. RESULTS There were three perioperative deaths (5.1%) and three perioperative neurological events, including one stroke (1.7%) and two transient ischemic attacks (3.4%). The combined mortality and stroke rate was 6.8%. With a mean follow-up of 25+/-21months, Kaplan-Meier estimates of the 4-yr survival rate, freedom from stroke, and stroke free survival were 78, 94 and 75% respectively. For comparison, during the same time period, the same group of surgeons performed 597 CEA in patients less than 80yr of age. The perioperative mortality and stroke rate was 0.3 and 2.5% respectively, with a combined mortality and stroke rate of 2.7%. Perioperative mortality was significantly higher in patients over 80yr of age (P<0.01). CONCLUSIONS CEA in octogenerians is associated with a higher mortality rate than in younger patients. However, good long term survival and freedom from stroke make CEA beneficial in octogenerians. With careful patient selection and perioperative management, CEA in octogenerians is worthwhile and should be advised in selected patients.

Progress in abdominal aortic aneurysm surgery: four decades of experience at a teaching center

The purpose of this study was to examine the changing trends in surgical management of patients with abdominal aortic aneurysms at a tertiary care teaching hospital over the past 40 years, by analysis of demographic data, perioperative variables and outcomes on all patients having abdominal aortic aneurysm surgery between 1955 and 1993. Some 1604 abdominal aortic aneurysms were assessed. The annual rate of abdominal aortic aneurysm surgery increased from 17.6 to 67.8 cases per year. The non-ruptured to ruptured abdominal aortic aneurysm ratio increased from 2.4:1 in the first decade to 3.4:1 in the last 5 years. In non-ruptured abdominal aortic aneurysm repairs, the following variables changed over the four decades: patients age over 80 years increased (2.4% to 8.0%; P<0.04), concomitant lower-limb occlusive disease increased (12.2% to 23.7%; P<0.02), prevalence of smaller aneurysms (4-6 cm) increased (16.0% to 54.2%; P<0.0001); intraoperative hypotension decreased (9.0% to 0.7%; P<0.0001), postoperative hemorrhage decreased (8.2% to 0.0%, P<0.0001), postoperative leg ischemia decreased (5.7% to 1.1%; P<0.02) and postoperative amputation rate decreased (3.2% to 0.0%; P<0.03). There was a significant decrease in perioperative mortality (17.0% to 3.4%; P<0.0001). For ruptured aneurysms, early operation (within 1 h of admission) increased from 8.7% to 55.8% (P<0.0001), prevalence of intraoperative hypotension decreased (50.0% to 23.5%; P<0.001), and major venous injury decreased (18.0% to 5.2%; P<0.05). Mortality, however, did not decrease significantly (54.2% to 44.2%; P=0.32). In conclusion, there was a significant decrease in mortality and morbidity associated with non-ruptured abdominal aortic aneurysm repair over the four decades studied. In addition, older patients with smaller aneurysms and more co-morbid conditions were operated on during this period. Mortality for patients operated on for ruptured abdominal aortic aneurysm repair has not changed significantly.

Successful innominate thromboembolectomy of a paradoxic embolus

A 54 year-old man had symptoms of acute right hemispheric cerebral ischemia. He was initially considered for participation in a trial of early thrombolysis in stroke, but an innominate artery embolus was found with no apparent arterial source. The embolus was removed by means of a combined brachial and carotid bifurcation approach to protect the cerebral vasculature from embolic fragmentation during extraction. Further investigation revealed deep venous thrombosis, evidence of pulmonary emboli, and a patent foramen ovale, supporting a diagnosis of paradoxic embolus. Additional treatment included anticoagulation and placement of an inferior vena caval filter. The unusual condition of paradoxic embolus is reviewed, and the management of this patient is discussed.

Crush syndrome complicating pneumatic antishock garment (PASG) use

We present a case of severe compartment syndrome complicated by rhabdomyolysis and acute renal failure (crush syndrome) following the use of a pneumatic antishock garment (PASG) with survival of the patient. Review of the literature reveals one other similar case but without survival. The aetiology of the complication is discussed and recommendations for the safe use of the PASG are made.

Primary vascular access for chronic hemodialysis : A comparison of arteriovenous fistulae with PTFE grafts

The purpose of this study was to compare patency rates of arteriovenous fistula (AVF) and polytetrafluoroethylene grafts (PTFE) for hemodialysis and the complications associated with each. All new permanent vascular access procedures for hemodialysis performed at one institution between January 1989 and December 1993 were reviewed with follow-up to December 1995. Patient demographics, secondary operations, complications, and length of stay were compared between the two types of access strategies. Seventy-seven PTFE and 89 AVF were performed in 166 patients. Age, sex, and frequency of diabetes were similar between the two groups. Primary patency rate at 36 months for AVF was 53%, compared with 16% for PTFE (p<0.01). Secondary patency rate at 36 months was 70% for AVF and 50% for PTFE (p<0.02). PTFE was associated with more hospital days per patient per year (26 vs 6.9), more infections (12 vs one during secondary patency interval), and a higher initial failure rate (19 vs eight) as compared with AVE. Patient survival rate at 4 years was higher for those with AVF (65% vs 52%). We conclude that an AVF as the primary access procedure for new renal dialysis patients is preferable to PTFE whenever possible.

Does Preoperative MIBI Scanning Lead to Improved Outcomes in Patients Undergoing Abdominal Aortic Aneurysm Surgery

Dipyridamole sestamibi nuclear scanning (MIBI) is a commonly used test to screen for cardiac disease in patients undergoing elective abdominal aortic aneurysm (AAA) surgery. However, its routine use for all patients is controversial. The purpose of this study was to determine whether MIBI scanning could identify high-risk patients and lead to decreased myocardial infarction (MI) and cardiac death when compared with patients who did not receive MIBI scanning preoperatively. The authors reviewed 212 consecutive patients undergoing elective AAA repair between January 1990 and December 1993. Data regarding preoperative cardiac status, MIBI scan results, and cardiovascular outcomes were collected. During this period, 92 patients had MIBI scans preoperatively while 120 patients underwent AAA surgery without MIBI scanning. The average ages for these two groups were 70 ±8 and 71 ±9 years, respectively. The frequency of coronary artery disease, angina, and previous MI in the MIBI group was 47%, 26%, and 29%, respectively. In the non-MIBI group, these frequencies were 39%, 23%, and 28%, respectively. Eleven patients were identified in the MIBI group to have moderate or large reversible defects. Of these, five underwent cardiac revascularization with no morbidity. The frequency of postoperative MI and death for the MIBI group was 1.1% (1/92) and 0%, respectively. In the non-MIBI group, it was 3.3% (4/120) and 1.7% (2/120), respectively (p=0.54). Preoperative MIBI scanning identified high-risk patients for AAA surgery. Following coronary revascularization for these high-risk patients, the overall MI and mortality rates were similar to those in patients who did not receive MIBI preoperatively.