Abdominal Aortic Reconstructive Surgery Research Articles

25, 50 and 75 years ago

25, 50 and 75 years ago

Age versus comorbidities as risk factors for complications after elective abdominal aortic reconstructive surgery

Purpose: This study estimated the association between age and in-hospital postoperative complications, controlling for known or suspected risk factors, in a series of patients undergoing elective abdominal aortic reconstructive surgery (AAR). Methods: This retrospective cohort study of outcome data with multivariate logistic regression analysis was conducted at Emory University Hospital, a tertiary care, university-affiliated hospital. All patients undergoing elective AAR between Jan 1, 1986, and Aug 1, 1996, were included (n = 856). An estimate of the odds ratio (OR) and 95% CI for the association between patient age and in-hospital major morbidity or mortality after elective AAR was made, controlling for significant risk factors. Results: Among the 856 patients, 170 had a nonfatal complication (136 with major and 34 with minor complications), and 11 patients (1.3%) died. The final logistic regression model demonstrated a mild association between increasing age and rate of major postoperative complications, including death (for each increase in age of 10 years: OR, 1.23; 95% CI, 1.00-1.52; P =.052). Other significant covariates in the final model included cardiac disease (OR, 2.84; 95% CI, 1.18-6.86; P =.020), pulmonary disease (OR, 1.96; 95% CI, 1.35-2.84; P =.0004), and renal disease (OR, 2.57; 95% CI, 1.66-3.99; P =.0001). Increasing age was associated with a moderate increase in the rate of death (for each increase in age of 10 years: OR, 2.74; 95% CI, 1.22-6.16; P =.015) in a model with cardiac disease as the only significant covariate (OR, 14.67; 95% CI, 3.46-62.16; P =.0003). Conclusion: For patients undergoing elective AAR, increasing patient age is associated with a small increase in risk for in-hospital morbidity or mortality. However, significant cardiac, pulmonary, or renal disease is associated with a much greater risk of postoperative complications, and, therefore, advanced age should not be the sole basis of exclusion for otherwise suitable candidates for elective AAR. (J Vasc Surg 2001;33:345-52.)

Can Predictors of Perioperative Myocardial Infarction in Patients Undergoing Vascular Surgery Be Identified? Sprung et al. (page 129)

Sprung et al. used the Vascular Surgery Registry at The Cleveland Clinic to identify patients from January 1989 through June 1997 who underwent vascular surgery and who had perioperative myocardial infarction (PMI) during the same hospital stay. Patients who underwent abdominal or thoracic aortic reconstructive surgery, carotid endarterectomy, or peripheral vascular surgery, performed with either general or neuraxial anesthesia, were included in the review. The authors analyzed associations among patient characteristics, type of anesthetic, and surgical risk factors for PMI, comparing the patients who experienced PMI with matched control patients (1:1) who did not.Information was collected for patients regarding preoperative cardiac history, comorbid conditions, treated diabetes mellitus, history of stroke, history of preoperative angina, and presence of preoperative coronary artery disease. Also analyzed were preoperative hematocrit and creatinine concentrations, intraoperative fluid use, estimated blood loss, and preoperative presence or absence of electrocardiographic changes consistent with myocardial disease or ischemia.During the time period studied, 107 patients experienced PMI during their hospital stay after vascular surgery. Twenty-two of these patients died. Four patients in the control group died during hospital stay; none of these died of cardiac causes. After a univariate analysis of the data, the authors found that the following factors were associated significantly with a greater risk of PMI: valvular disease, previous congestive heart failure, surgery performed on an emergency basis, general anesthesia, preoperative diagnosis of coronary artery disease, lower preoperative and postoperative hemoglobin concentrations, increased intraoperative bleeding (as determined by the amount of cell-salvaged blood), and a lower ejection fraction. The risk of cardiac death was increased by age, recent congestive heart failure, type of surgery, lower intraoperative diastolic blood pressure, and new intraoperative ST-T changes. Having undergone coronary artery bypass graft surgery even more than 12 months before vascular surgery reduced the mortality rate after PMI by 79%.

The Utility of Hemodynamic Measurements Acquired by Pulmonary Artery Catheterization

Background: Concerns about the utility of pulmonary artery catheters (PAC) stimulated us to assess the impact of one of the parameters measured by the PAC, the pulmonary capillary wedge pressure (PCWP), on our clinical practice. Methods: The PCWP was recorded at 4- to 6-hour intervals on 50 patients for the first 48 hours following aortic aneurysm repair. We then reviewed the patients’ records looking for evidence that the PCWP measurements were used to guide therapy. For the purpose of the study, we anticipated the administration of diuretics for PCWP ≥18 mm Hg and volume resuscitation for PCWP ≤8 mm Hg. Data were correlated using Pearson rank correlation coefficient using a P <0.05 to determine statistical significance. Results: Patients with PCWPs <8 mm Hg were more likely to be treated with volume resuscitation ( P <0.05). There was no other correlation between PCWP measurements and fluid or pharmacologic management. Conclusions: Data derived from the PAC are infrequently used to guide therapy in patients who undergo abdominal aortic reconstructive surgery.

Prognostic factors in elective aortic reconstructive surgery.

The present study was carried out to determine the risk factors associated with peri-operative mortality and long-term survival in patients undergoing abdominal aortic reconstructive surgery (ARS). A retrospective review was performed of the case notes of all patients having ARS at a university teaching hospital during a 5.5-year period, and their details entered onto a pro forma. A total of 252 patients underwent ARS between July 1989 and December 1994. The peri-operative mortality was 7.5%. The most frequent adverse events were cardiac events, accounting for 8 (42%) of the peri-operative deaths. The risk of a peri-operative cerebrovascular accident was low (n = 3, 1.2%) as was the risk of peri-operative renal failure requiring dialysis (n = 3, 1.2%). Factors independently linked to increased peri-operative mortality included moderate-to-severe hypertension (P = 0.05, odds ratio = 3.54), those with renal impairment (P = 0.05, odds ratio = 2.69), and blood transfusion requirements (P < 0.001, odds ratio = 1.26). Long-term survival was independently shortened by occlusive disease (P = 0.004, hazard ratio = 2.78) and ischaemic heart disease (P < 0.001, hazard ratio = 3.58). The risks of ARS were significantly increased in patients with severe hypertension, those with renal impairment and those requiring blood transfusion. Long-term survival was shortened for those patients with occlusive aortic disease and ischaemic heart disease. These risk factors should be carefully assessed in each patient before performing elective ARS.

Pattern of 72-hour intragastric acidity in a homogeneous group of intensive care unit patients.

To gain insight into the variation over time of gastric acidity in postoperative ICU patients, intragastric pH was prospectively studied in patients undergoing elective abdominal aortic reconstructive surgery during a 72-hr intra- and postoperative period. Intragastric pH was monitored continuously in 14 patients with combined glass electrodes. During the day of surgery (day 1), the median 24-hr pH for all patients was 6.25 (5.8-7.0, IQR). However, three of the 14 studied patients had a median 24-hr pH of 1.8. The median 24-hr pH throughout day 2 for all was 2.45 (1.6-4.7, P = 0.001). The median 24-hr pH on day 3 was 1.6 (1.5-2.1, P = 0.001). Median 8-hr pH values demonstrate a remarkable interpatient and intraindividual variation in the course of the postoperative period. A progressive lowering of the intragastric pH was observed in the first 40 hr. From the 40- to 48-hr interval until the end of the study, no further significant decrease was found. The intragastric pH was above 4, 74% of the time during day 1, 39% during day 2 (P = 0.006) and 16% during day 3 (P = 0.003). Percentage of time above 4 on day 2 was significantly higher than on day 3 (P = 0.04). In conclusion, since gastric acid and pepsin seem to play a role in stress ulceration, this study suggests some patients are at risk of stress ulceration from the beginning of surgery, but most patients become at risk of stress ulceration in the course of the postoperative period.

The value of pulmonary artery and central venous monitoring in patients undergoing abdominal aortic reconstructive surgery:

One hundred two patients undergoing abdominal aortic reconstructive surgery were prospectively, randomly allocated to two groups, one of which was monitored with a central venous catheter and the other with a pulmonary artery catheter. Patients with uncompensated cardiopulmonary or renal disease were excluded from the study. General anesthesia was administered for the surgical procedure, and the patients were followed through hospital discharge. No statistically significant differences occurred between the two groups with regard to morbidity (perioperative cardiac, pulmonary or renal sequelae), mortality rate, duration of intensive care, postoperative hospital stay, or cost of hospitalization. The one statistically significant difference between groups was the professional fee charged for anesthetic care, which was higher for patients with pulmonary artery catheters than for those with central venous catheters. In conclusion, we prospectively gathered data from most patients presented for abdominal aortic reconstructive surgery. Our data seem to indicate that the choice of central venous catheter or pulmonary artery catheter monitoring makes little difference in outcome after abdominal aortic reconstructive surgery, and that for many patients pulmonary artery catheters are not necessary to give appropriate, adequate care. Because of the size of the sample, however, declarations of epidemiologic significance would be unfounded. Therefore large-scale, multicenter studies addressing such outcomes remain necessary.

Pulmonary hypertensive response to declamping of the aorta during abdominal aortic reconstructive surgery-role of metabolic derangement and anaphylatoxin in the reaction.

Metabolic parameters and anaphylatoxin activities in mixed venous blood were measured in 16 patients undergoing abdominal aortic reconstructive surgery to study the mechanism of pulmonary hypertensive response after aortic declamping. This reaction was confirmed by a rise in ratio between mean pulmonary arterial pressure and mean systemic arterial pressure (Pp/Ps). Aortic declamping was followed by a significant increase in lactate level and lactate-pyruvate ratio (L/P ratio) as compared with pre-declamping level ( P << 0.01). Although anaphylatoxin C3a concentration rose significantly after declamping ( P << 0.01), C5a showed no change at any stage. When the patients were divided into two groups according to the degree of Pp/Ps change by declamping, significant elevation of L/P ratio and C3a level were observed in the group with higher increase (Post-/Pre-declamp value >/=1.25) of Pp/Ps compared to the lower (>>1.25) group. After declamping, in the higher Pp/Ps group, a positive correlation existed not only between Pp/Ps change and aortic clamp time, but also between L/P ratio and C3a level. The present results suggest that muscular metabolic derangement distal to the aortic clamp may play an important role in the development of post-declamping pulmonary hypertensive response through anaphylatoxin C3a.

The role of prostacyclin in the mesenteric traction syndrome during anesthesia for abdominal aortic reconstructive surgery.

Mesenteric traction syndrome consists of sudden tachycardia, hypotension, and cutaneous hyperemia, and frequently occurs during mesenteric traction in patients undergoing abdominal aortic aneurysm (AAA) reconstructive surgery. The etiology and clinical impact of this phenomenon are unknown, but the symptoms suggest a release of vasoactive materials from the mesenteric vascular bed. Thirty-one patients who underwent AAA surgery were studied. Mesenteric traction was accompanied by a decrease in systolic (p = 0.005) and diastolic (p less than 0.05) blood pressures, and in systemic vascular resistance (p less than 0.005), and was accompanied by an increase in heart rate (HR) (p less than 0.005), and cardiac output (p = 0.01). These hemodynamic changes coincided with an increase (p less than 0.001) in plasma concentrations of 6-keto-prostaglandin F1 (6-K-PGF1). No apparent change was found in prostaglandin E2, thromboxane B2, and histamine concentrations. The concentration of 6-K-PGF1 was correlated with diastolic blood pressure (r = -0.52, p less than 0.005) and HR (r = 0.65, p less than 0.001). Cutaneous hyperemia was observed in 58% of the patients. In an additional six patients, who had taken aspirin daily before AAA surgery, no significant changes were observed in the hemodynamic measurements or 6-K-PGF1 concentrations. These data suggest that mesenteric traction syndrome may be mediated at least in part by a selective release of prostacyclin.

Dipyridamole-Thallium Scanning in Patients Undergoing Vascular Surgery

To the Editor.— With regard to the article entitled Dipyridamole-Thallium Scanning in Patients Undergoing Vascular Surgery by Eagle et al, 1 a few comments are offered. It is unclear what is the value of the authors' validation set. Although this validation was done prospectively, it did not add any further information. In addition, the patients' surgical procedures were different in the two groups. The incidence of significant coronary disease in asymptomatic candidates for abdominal aortic surgery is known to be higher than for carotid or distal ischemic extremity surgery. 2 A true validation set, if necessary, would have just consisted of patients due for abdominal aortic reconstructive surgery. The study looked at outcome but treated anesthesia and surgery as a constant. Previous studies have documented that choice of anesthesia and the anesthesiologist may make a significant difference in the outcome of high-risk cardiac procedures. 3,4 These variables were not assessed.

Hemodynamic monitoring of patients undergoing abdominal aortic surgery

Cardiac decompensation is clearly the major complication of aortic reconstructive surgery that leads to morbidity. Major changes in intravascular volume, third spacing, and increased systemic vascular resistance are extremely stressful to the diseased heart. Hemodynamic monitoring is readily available to provide an accurate evaluation of myocardial sensitivity and to allow for appropriate pharmacologic manipulation to preclude cardiac catastrophe. We believe all patients undergoing abdominal aortic reconstructive surgery should receive the benefit of pulmonary artery catheterization and intraarterial monitoring. The only requirement is a staff of surgeons, anesthesiologists, and nurses capable of correct interpretation of the data and use of drug therapy based on this information. The benefits are an accurate assessment of cardiac function with the ability to modulate the patient's hemodynamic values, preventing volume shifts, hypertensive and hypotensive crises, and abnormal fluctuations in preload and afterload, and ultimately a safer perioperative course.

Hemodynamic and metabolic effects of abdominal aortic crossclamping

The hemodynamic and metabolic effects of aortic crossclamping and declamping were studied in 10 patients undergoing abdominal aortic reconstructive surgery. After placement of pulmonary and radial arterial catheters, measurements were obtained preoperatively, during the procedure according to protocol, and postoperatively. Pulmonary arterial wedge pressure was maintained at 10 to 15 mm Hg throughout the operation. Aortic cross clamping produced a significant increase in systemic arteriolar resistance and systolic blood pressure, with no change noted in the left ventricular stroke work index. Declamping decreased systemic resistance and produced no change in the left ventricular stroke work index. Clamping and declamping resulted in elevations of serum lactate. Central venous pressure correlated with pulmonary arterial wedge pressure in each patient and in the entire group. Cardiac function is not decreased by aortic crossclamping, and central venous pressure can usually be used for hemodynamic monitoring in these patients.

Late complications of abdominal aortic reconstructive surgery: roentgen evaluation.

During a 5-year period from 1969 to 1974, 53 (8.5%) of 631 patients developed late complications following abdominal aortic reconstructive surgery. Occlusion was the most frequent complication and occurred in 4%. Others included stenosis, false aneurysm, enteric fistula and infection. Late complications were demonstrated by roentgenographic methods. Angiography was the most valuable roentgen study. It is indicated in all patients suspected of having delayed complications except those with unstable life-threatening hemorrhage. Additional roentgenographic studies including the barium enema and barium meal may help make the diagnosis and exclude other entities. In any patient with an abdominal aortic graft and gastrointestinal bleeding, the diagnosis of an aorto-enteric fistula should be considered until otherwise proven.

Aortoenteric and paraprosthetic-enteric fistulas: radiologic findings

Ten cases of graft-intestinal fistulas occurred in 712 patients who had undergone abdominal aortic reconstructive surgery. Radiographic abnormalities were demonstrated in eight--three by conventional barium gastrointestinal examinations and five by angiography. A high index of suspicion of the condition and an aggressive radiologic workup are recommended.

Vascular Insufficiency of the Colon as a Complication of Abdominal Aortic Surgery

Vascular insufficiency of the descending colon, as a complication of abdominal aortic reconstructive surgery, occurs with sufficient frequency that its radiological findings should be appreciated. The incidence of colon infarction following abdominal aortic resection varies between 1 and 10 per cent (Bernatz, 1960; Smith and Szilagyi, 1960). Since cases of this particular entity were difficult to find in the radiological literature, it was decided to report the following case. F.M., No. 142098, is a 60-year-old white male carpenter who entered Colorado General Hospital in September of 1962 with the chief complaint of progressive decrease in the calibre of his stools. In August of 1961 the patient was diagnosed as having porphyria hepatica. An abdominal aneurysm was also discovered at this time. A barium enema, done because of symptoms not too unlike those which necessitated his most recent admission, was interpreted as within normal limits (Fig. 1). A graft replacement of the aneurysm was contemplated, bu...