Elective Abdominal Aortic Aneurysm Surgery Research Articles

Emergency Abdominal Aortic Aneurysm Repair: Factors Affecting Survival and Long-Term Results

Elective surgery for abdominal aortic aneurysm (AAA) has become a safe operation, although the mortality related to ruptured AAA remains considerably high. Factors affecting survival of 32 consecutive patients with ruptured AAAs were evaluated. The postoperative mortality was 50% (16/32) compared with 1.9% for 103 elective AAA patients. Factors associated with poor prognosis were systolic blood pressure of less than 90 mmHg and severe metabolic acidosis on arrival to the hospital, size of the aneurysm, and massive blood transfusion. The high mortality and morbidity rates of the ruptured AAA patients emphasize the need for early and aggressive treatment of AAA in the elective setting in the patient at high risk. In follow-up study, however, the actuarial survival following ruptured AAA surgery, excluding hospital mortality, was 77% at five years. It did not differ statistically from that of patients who had elective AAA surgery. The quality of life survey following surgery showed no discernible differences between ruptured and elective AAA surgery.

Neuroendocrine and haemodynamic responses to abdominal aortic cross clamp and release during high-dose opiate-oxygen isoflurane anaesthesia

The haemodynamic and neuroendocrine responses and beta adrenoceptor distribution associated with aortic cross clamping and release were quantified in 14 patients undergoing elective abdominal aortic aneurysm surgery using a high-dose opiate-oxygen-isoflurane anaesthetic technique. These changes were correlated with neutrophil beta adrenoceptor distribution. Aortic cross clamp application was associated with increased systemic vascular resistance (SVR), and decreased cardiac index (CI). Left ventricular stroke work index remained constant during the period of cross clamp application and following release. Cross clamp release was associated with increased CI and decreased SVR. Plasma cortisol concentrations did not change during the study period. Plasma catecholamine concentrations, although elevated prior to surgery, remained unchanged during aortic cross clamping and following release. The percentage of internalised beta adrenoceptors was elevated before surgery and was unaffected by surgical intervention. This study suggests that a high-dose fentanyl-oxygen-isoflurane anaesthetic technique in a patient population with high circulating catecholamine levels and downregulation of beta adrenoceptors is associated with cardiovascular stability and attenuated neuroendocrine responses.

Effects of major and minor surgery on plasma glutamine and cytokine levels.

The plasma levels of glutamine and cytokines have been measured frequently in patients before, during, and after elective abdominal aortic aneurysm surgery ("major surgery") or inguinal hernia repair ("minor surgery"). The plasma glutamine level declined rapidly following major surgery and remained markedly below preoperative levels until at least 7 days after surgery. This response of the plasma glutamine levels was significantly correlated with the production of interleukin 6 but not with that of interleukin 1, tumor necrosis factor, or interferon gamma. In contrast, following minor surgery, the plasma glutamine level was unchanged and the elaboration of interleukin 6 was attenuated. The decrease in the plasma glutamine level following major surgery may contribute to the state of immunosuppression, which follows major surgery, and the relationship between amino acid and cytokine metabolism is worthy of further study.

Use of the Cell Saver during Elective Abdominal Aortic Aneurysm Surgery — Influence on Transfusion with Bank Blood. A Retrospective Survey

One hundred and two patients undergoing elective abdominal aortic aneurysm repair and admitted to ICU at RPAH in 1989/90 were studied. In forty patients a cell saver was used during the operative procedure (Group CS) while in the remaining sixty-two patients intraoperative blood loss was drained and discarded conventionally (Group NCS). Preoperative ASA grade and postoperative APACHE score were similar in these two groups. The amount of bank blood transfused intraoperatively was less in Group CS than in Group NCS (0.6 +/- 0.2 vs 3.3 +/- 0.3 units) (mean +/- SEM) (P less than 0.0001). The total amount of bank blood transfused during hospital admission was also less in Group CS (1.5 +/- 0.4 vs 4.8 +/- 0.4 units, P less than 0.0001). Of Group CS, 22 patients (55%) received no bank blood compared to two patients (3%) in Group NCS. There was no difference between the groups with respect to postoperative haemoglobin and creatinine levels. ICU stay was similar in both groups. We conclude that use of the cell saver reduces perioperative bank blood transfusion in elective abdominal aortic surgery.

Anticoagulation in abdominal aortic aneurysm surgery: The approach of vascular surgeons in Great Britain and Ireland

A questionnaire was sent to 283 vascular surgeons in Great Britain and Ireland regarding their use of heparin in elective abdominal aortic aneurysm surgery. The answers form the basis of this study and show that there is great variation. The majority of surgeons routinely anticoagulate their patients peroperatively. Heparin is usually given intravenously--most giving the drug 2 to 3 min prior to cross clamping the aorta. Approximately half of the respondents use the same dose in all patients, whilst the remainder vary the dose, usually on the basis of weight or "size". Most surgeons use 5000 units but the range of dose varies from 400 to 20,000 units. Just under a quarter of surgeons continue to anticoagulate their patients postoperatively, almost all of these using subcutaneous heparin for prophylaxis against deep vein thrombosis. Only approximately 10% of surgeons routinely reverse the heparin with protamine.

Noncardiogenic pulmonary edema after abdominal aortic aneurysm surgery.

Limb ischemia in experimental animals leads to white blood cell (WBC) and thromboxane (Tx)A2 dependent pulmonary dysfunction. This study examines the pulmonary sequelae of lower torso ischemia in 20 consecutive patients aged 63 +/- 5 years (mean +/- SEM) who underwent elective abdominal aortic aneurysm surgery. After 30 minutes of aortic cross-clamping, plasma TxB2 levels had risen from 77 +/- 26 pg/ml to 359 +/- 165 pg/ml (p less than 0.01) and was temporally related to increases in mean pulmonary artery pressure (MPAP) from 18 +/- 1 to 23 +/- 3 mmHg (p less than 0.01), as well as to increases in pulmonary vascular resistance (PVR) from 0.07 +/- 0.02 to 0.12 +/- 0.02 mmHg sec/ml (p less than 0.01). Each time that the aortic clamp was repositioned and with final declamping, after 83 +/- 10 minutes, there were further increases in MPAP to a peak of 32 +/- 2 mmHg (p less than 0.01) and in PVR to 0.26 +/- 0.030 mmHg sec/ml (p less than 0.01), corresponding to a plasma TxB2 level of 406 +/- 177 pg/ml (p less than 0.01). MPAP and PVR returned to baseline values within 30 minutes of declamping. Ten minutes after removal of the aortic clamp, platelet levels had fallen from 180 +/- 41 to 97 +/- 17 X 10(3)/mm3 (p less than 0.01) and WBC levels from 8900 +/- 1100 to 4700 +/- 400/mm3 (p less than 0.01). Both platelets and WBC returned towards normal levels, but at 24 hours, while WBC was elevated at 13000 +/- 900/mm3 (p less than 0.01), platelets were 44% of baseline at 135 +/- 14 X 10(3)/mm3 (p less than 0.01). Four to 8 hours after surgery, pulmonary dysfunction was manifest by increases in physiologic shunt from 9 +/- 2% to 16 +/- 2% (p less than 0.01), and peak inspiratory pressure (PIP) from 23 +/- 2 to 33 +/- 2 cmH2O (p less than 0.01). Chest radiography demonstrated interstitial pulmonary edema in all patients, whereas pulmonary artery wedge pressure was 12 +/- 2 mmHg, excluding the possibility of left ventricular failure. After 24 hours, pulmonary edema had resolved, and the PIP and PaO2 had both returned to baseline. These data indicate that reperfusion of the ischemic lower torso leads to the synthesis of TxA2, an event temporally related to pulmonary hypertension and transient leukopenia with subsequent pulmonary microvascular injury manifest by interstitial edema.

Long-term survival and quality of life following ruptured abdominal aortic aneurysm.

To document both the long-term survival and the quality of life of patients following surgery for ruptured abdominal aortic aneurysm (AAA), the records of 65 patients with ruptured AAA resection were compared with those of 100 who underwent elective AAA resection. The actuarial survival following ruptured aneurysm surgery was 92%, 51%, and 51% at 1, 5, and 10 years, respectively, and did not differ statistically for patients after elective AAA surgery or for an age- and sex-matched sample from the general population. Based on responses to a quality of life survey, there were no discernible differences in life-style, degree of independence, or productivity following either ruptured or elective AAA surgery. Survivors of ruptured AAA have an excellent long-term prognosis and expectation for a good quality of life.