Urinary L-valyl proline in patients with aortic aneurysms

Recent evidence indicates that metabolism of elastin may be altered in patients with different types of infrarenal aortic disease and that the phenotypic expression of aortic disease may be dependent on the balance between aortic elastase and antiprotease activity. The dipeptide L-valyl proline (LVP) is a specific amino acid sequence for elastin and can be quantitated by high performance liquid chromatography analysis of the urine. This study was done to determine if alterations in systemic elastin metabolism could be detected in patients with different types of infrarenal aortic disease by quantitating urinary LVP. Patients were divided into one of five groups and had urine analyzed for LVP. These are control, no known aortic disease (n = 12); occlusive aortic disease (n = 10); elective abdominal aortic aneurysms (AAA) (n = 26); ruptured AAA (n = 5), and multiple aneurysms (n = 4). Urine values were correlated with aortic elastase and aortic antiprotease activity. Urinary LVP was significantly higher in patients with multiple aneurysms (1,209 micrograms per milliliter of urine) as compared with all of the other groups. Patients with elective AAA had significantly higher urinary LVP (40.5 micrograms per milliliter of urine) than patients with occlusive disease (9.1 micrograms per milliliter of urine) and those in the control group (4.2 micrograms per milliliter of urine). Patients with ruptured AAA did not have significantly elevated urinary LVP compared with other groups (18.6 micrograms per milliliter of urine). Urinary LVP increased significantly as aortic elastase and aortic elastase and antiprotease activity increased. These data suggest that elastin metabolism, as reflected by urinary LVP, is altered in patients with aortic aneurysmal disease and provide further evidence to support the concept that systemic elastin metabolism is altered in patients with different types of infrarenal aortic pathologic findings.     

Characterization of human aortic elastase found in patients with abdominal aortic aneurysms

Recent evidence indicates that the homeostatic balance between elastase and antiprotease activity is altered in the infrarenal aorta of those patients with different types of aortic pathologic findings. The specific properties of elastase found in the aorta of patients with abdominal aortic aneurysms (AAA) are discussed herein. Activity of elastase extracted from ten pooled AAA specimens was observed when incubated with several inhibitors: 13.2 per cent for phenyl-suphonyl flouride (PSF); 43.3 per cent for ethylenediaminetetraacetic acid (EDTA); 77.7 per cent for pepstatin; 137.0 per cent for leupeptin, and 24.0 per cent for alpha-1-antitrypsin. Irreversible inhibition by PSF indicates that the elastase is a serine protease. The elastase is most likely not a metallo enzyme, since it had no absolute requirement for divalent cations as indicated by only partial inhibition by EDTA. Elastase activity is most likely not due to cathepsins B or D, since cathepsins are active in an acid pH and selectively inhibited by leupeptin and pepstatin. The pH curve revealed a maximum activity at pH 8.2 and elastase activity was significantly inhibited by alpha-1-antitrypsin in a dose response manner determining functional elastase activity. These data indicate that the elastase in the aorta of patients with an AAA has the exact properties of the serine elastase found in the smooth muscle cells of the aorta in rats. These results also confirm the critical role of alpha-1-antitrypsin in determining functional elastase activity. Smooth muscle cell regulation of elastin metabolism may be important in determining why some patients have AAA and others have occlusive aortic disease develop.     

Factors influencing the rupture of abdominal aortic aneurysms

The gross findings of 49,144 autopsies performed at two major hospitals in Rome were reviewed. There were 297 patients who were found to have atherosclerotic abdominal aortic aneurysm (AAA). The aneurysm was intact in 220 (74 per cent) and ruptured in 77 (26 per cent). The occurrence of aneurysm rupture was correlated to 17 variables by univariate and multivariate statistical analysis. Covariates found to be independently predictive of the rupture of AAA were the size of the aneurysm (p less than 0.001), arterial hypertension (p less than 0.001) and the presence of bronchiectasis (p less than 0.025.). Over-all, bronchiectasis was more common among patients with AAA than in the age-adjusted and sex-adjusted control population. The simultaneous presence of bronchiectasis and AAA suggests the presence of some inherited or acquired tendency to have ectasia of the connective tissue, aneurysm formation and rupture development.     

Relationship between proteolytic enzymes and atherosclerosis in aortic aneurysms.

Aortic elastase and aortic collagenase were assayed in 38 patients who underwent an operation for thoracic or infrarenal aneurysm or infrarenal aortic occlusive disease and in 15 control patients (heart or kidney donors). Elastase was elevated in normal aortas of the infrarenal region (1.10 milliunits per gram, p less than 0.05), and in atherosclerotic descendens aneurysms (1.24 milliunits per gram, p less than 0.05), compared with the ascending aorta, when normal; aneurysmatic specimens revealed similar low elastolytic activities (0.10 milliunits per gram). The highest elastase content was found in infrarenal aneurysms (4.65 milliunits per gram). Collagenase assays yielded no significant differences, although higher activities were extracted from aortas of the infrarenal region. Coexistent atherosclerosis and wall destruction were evaluated by macroscopic and histologic investigation. All infrarenal specimens demonstrated severe atherosclerotic wall degeneration with depletion of elastic fibers. As the atherosclerotic specimens did not differ from normal aortas by protease assay, the higher elastase of infrarenal samples compared with the thoracic aorta suggests a more rapid fiber metabolism in the infrarenal region. The significantly elevated elastolytic activity of infrarenal aneurysms points to the decisive role of elastase in infrarenal aneurysm formation.     

Twenty-one years' experience with ruptured abdominal aortic aneurysms.

The surgical experience with 107 ruptured abdominal aortic aneurysms at this hospital during the years 1953 to 1975 has been reviewed. The operative mortality rate during the first ten years of this study was 86 per cent, but since 1966, it has fallen to 40 per cent. These improved mortality statistics are related primarily to improved techniques for controlling operative blood loss and minimizing the time of aortic cross clamping. The use of an intra-aortic balloon has been useful in this regard. Twenty-four additional patients died from ruptured aneurysms without undergoing operation, all before 1966. Only seven had a correct diagnosis prior to death, and these seven serve to emphasize the importance of being alert to the diagnosis of ruptured aneurysm which often masquerades as urologic or orthopedic problems because of the frequent symptoms of back, abdominal, flank or groin pain. Since the operative mortality rate for elective resection of the aneurysm has been less than 1 per cent at this institution during the last eight years, we believe we are justified in encouraging prompt resection of aneurysms on an elective basis to eliminate the high mortality rate that still accompanies rupture of the aneurysm.     

Abdominal aortic aneurysm resection in patients more than 80 years old

Improvement in anesthetic and surgical techniques has prompted a more aggressive approach to repair of abdominal aortic aneurysms in patients more than 80 years old. In order to determine if surgical treatment is justified, all of the patients who were more than 80 years old admitted to the hospital during the ten year period from 1974 to 1983 with the diagnosis of abdominal aortic aneurysm were reviewed. A total of 90 patients were available for analysis. The mortality of the 18 patients treated conservatively for ruptured aortic aneurysms was 100 per cent. Ten of the 27 patients operated upon for a ruptured aneurysm died yielding a mortality of 37 per cent. Eleven patients with symptomatic aneurysms had urgent repair with a mortality of 27 per cent. Only one of the 34 patients undergoing elective aneurysm repair died. There was no difference in the size of aneurysms among the groups. Although the ruptured aneurysms required more blood (10.2 +/- 3.7 units), there was no difference between the other two groups (symptomatic 4.5 +/- 3.1 units, elective 4.6 +/- 2.8 units). There was significantly fewer myocardial and renal complications in the elective group, although the sole death in this group was from myocardial infarction. Based upon these observations, we recommend aggressive elective therapy for selected patients who are more than 80 years of age with asymptomatic abdominal aortic aneurysms. Although the mortality is higher in those patients with symptomatic or ruptured aneurysms, it is not formidable, and therefore, repair should not be ruled out on the basis of age alone.     

Two year prospective analysis of the Oxford experience with surgical treatment of abdominal aortic aneurysm

During the two years from 1 November 1985 to 31 October 1987, 177 patients were admitted to a hospital in Oxford with the diagnosis of abdominal aortic aneurysm (AAA). The aneurysm had ruptured in 88 patients, of whom 75 underwent emergent surgical treatment, yielding an operative mortality rate of 36 per cent. Of the 13 patients who did not have surgical treatment, two died before transfer to the operating room; in the other 11 patients, a deliberate decision was made not to undertake surgical treatment--in ten patients, the reason was an age of 85 years or more and in one patient, severe debilitating Parkinson's disease. Emergent operations were done upon another 15 patients--11 who had acute aneurysm and four in whom symptoms were not caused by an aneurysm. Emergent operations for ruptured or acute aneurysms represented 55 per cent of all operations for AAA. This high proportion and large number of emergent operations is in marked contrast with the experience of comparable specialist vascular surgical units in the United States. The 24-fold difference in mortality rates between surgical procedures performed electively and for ruptured aneurysm suggests that a considerable impact on over-all mortality could be achieved by a substantial increase in referral of patients     

Incidence of ischemic colitis following abdominal aortic reconstruction.

The incidence of ischemic colitis following abdominal aortic reconstruction was determined by postoperative colonoscopy during a three year period. The over-all incidence of colitis was 11 of 163 patients who underwent elective or urgent reconstruction of the abdominal aorta for aneurysmal and occlusive diseases. The incidence of ischemic colitis for patients who survived resection of ruptured abdominal aortic aneurysms was higher, although the colonoscopy rate was lower. The incidence might have been even higher if all patients surviving resection of ruptured abdominal aneurysms had undergone colonoscopy.     

Acute acalculous cholecystitis complicating aortic aneurysm repair

In a series of 374 consecutive abdominal aortic aneurysmal repairs, the incidence of acute acalculous cholecystitis was 1.1 per cent. This complication occurred in only one of 352 patients (0.3 per cent) after elective aneurysmorraphy, as compared with three of 22 (13.6 per cent) after emergency repair of a ruptured aneurysm. This difference proved highly significant (p = 0.0001). All of the patients who had postoperative acute cholecystitis after aortic aneurysmal repair had acalculous disease. A mortality rate of 50 per cent was noted for this complication. Technetium cholescintigraphy proved the most valuable diagnostic study when acute cholecystitis was suspected.     

Zero operative mortality rate in 109 consecutive elective aortic operations performed by residents

One hundred and nine consecutive elective abdominal aortic operations were performed at the Veterans Administration Medical Center San Diego between 1984 and 1987. All of the operating surgeons were residents in general surgery who were assisted by attending staff. The mean age of the patients was 66.1 years and 34 patients were 70.0 years or older. The indication for operation was aortic aneurysm in 69 and aortoiliac occlusive disease in 40. Fifteen patients underwent highly complex procedures. The mean duration of operation was 5.6 hours, mean aortic clamp time was 72 minutes and mean volume of blood replacement was 1,186 milliliters. There was no operative mortality. Twenty-nine patients had 32 nonfatal complications. Patency of the graft was 100 per cent at discharge. We conclude that excellent clinical results with complex elective aortic operations can be achieved by surgical residents with appropriate supervision.     

Abdominal aortic aneurysm and the pseudorupture syndrome

A consistently high mortality for ruptured abdominal aortic aneurysm has given rise to an aggressive approach in the management of these patients. However, there is a group of patients who present with signs and symptoms suggesting a ruptured abdominal aortic aneurysm but instead have other life threatening conditions. These patients and their management are presented herein.     

A twenty-two year review of elective resection of abdominal aortic aneurysms.

The clinical presentation and history of abdominal aortic aneurysm has changed little in the last 22 years. The improved results of elective resection of these lesions have occurred subsequent to advances in various aspects of treatment of this disease as well as increased experience in surgical management. The operative mortality associated with elective resection of abdominal aortic aneurysms has dropped to such a level that elective intervention is reinforced as the treatment of choice for this lesion. It is hoped that, with the continued improvement in the diagnostic phase resulting in earlier detection and surgical intervention, there may be a further reduction in the incidence of rupture of abdominal aortic aneurysms and further prolongation of life in those patients in whom such lesions develop.     

Factors affecting survival of patients with ruptured abdominal aortic aneurysm in a West Virginia community

The hospital records for patients treated for ruptured abdominal aortic aneurysms in southern West Virginia during a recent five year period were reviewed. The over-all mortality rate was 62 per cent. Patients with intraperitoneal rupture had a higher mortality rate (97 per cent) than patients with retroperitoneal rupture (25 per cent). Patients at increased risk were more than 80 years of age, presented with syncope, experienced a short duration of symptoms before seeking medical attention, had preoperative systolic blood pressure levels of less than 90 millimeters of mercury and had a preoperative hemoglobin level of less than 8. Other factors associated with death were a delay in beginning surgical treatment, a larger total blood loss and amount of blood transfused. The results of multivariate analysis demonstrated that preoperative blood pressure, preoperative hemoglobin, presence of syncope and the amount of blood loss were, in large part, reflections of the type of rupture and had only slight independent relationship to mortality. The most effective method of preventing fatal outcome is elective resection of the aneurysms before rupture occurs.     

The risk of ligation of the left renal vein in resection of the abdominal aortic aneurysm

The left renal vein can be ligated during aortic operation to attain better access to the perirenal aorta. This maneuver has been considered safe, with a low incidence of postoperative renal complications. This study was done to evaluate the risk of left renal vein ligation and its influence on renal function in patients with elective resection of abdominal aortic aneurysms. The records of 332 patients undergoing elective repair of abdominal aortic aneurysms during a five year period were reviewed. The clinical and operative data of patients who had left renal vein ligation and those who did not were similar. Left renal vein ligation was not associated with an increased mortality rate but was strongly associated with an increase in serum creatinine level and a clinical diagnosis of postoperative azotemia. Nine of 13 patients who had left renal vein ligation had postoperative azotemia compared with 21 of 319 patients without left renal vein ligation (p less than 0.001). The mean change of preoperative and postoperative creatinine value was an increase of 1.92 milligrams per deciliter in patients with left renal vein ligation in contrast with 0.26 milligram per deciliter in patients without ligation (p less than 0.00075). Thus, ligation of the left renal vein increases the risk of postoperative renal complications and its use should be selective.     

Percutaneous aortic balloon occlusion

A new technique of percutaneous occlusion of the aorta is described herein. The catheter is inserted through the femoral artery and has a central lumen for placement over a safety guide, if needed. The method is applicable in instances of exsanguinating hemorrhage, such as ruptured abdominal aortic aneurysm.     

Comparative analysis of retroperitoneal and transperitoneal aortic replacement for aneurysm

Transabdominal aortic replacement is the most widely accepted surgical approach in the treatment of infrarenal abdominal aortic aneurysms (AAA) with an enviable mortality rate of 2 to 5 per cent. This approach, however, is attended by significant intraoperative loss of fluid and subsequent translocation as well as impaired postoperative pulmonary function and ileus. Although the retroperitoneal exposure of the aorta was used for the first repair of an AAA by Dubost and has been championed more recently by others, it has not been widely accepted. Experience suggests, however, that the exposure is as good and that postoperative morbidity is significantly less than that with the transperitoneal approach. In the past five years, we have surgically treated 299 AAA, 106 by the transabdominal route and 193 by the extended retroperitoneal approach. In 133 of the 193 patients upon whom the retroperitoneal approach was used, the aneurysm was left intact after division of the infrarenal aorta for an end to end proximal anastomosis of an aortoaortic to iliac to femoral bypass. There has been a significant reduction in the intraoperative replacement of fluid and blood, in postoperative respiratory support, in length of time in the intensive care unit and in occurrence of postoperative ileus when compared with the transabdominal endoaneurysmorrhaphy approach. Furthermore, the exposure, particularly upon the obese patient, is superior. Findings from this experience using the retroperitoneal approach for repair of AAA indicate that it results in less over-all physiologic disturbance of the patient.     

Hand-assisted laparoscopic surgery for abdominal aortic aneurysm.

There is a trend toward the use of minimally invasive surgery and limited incision for the surgical repair of abdominal aortic aneurysm (AAA). Conventional AAA repair is performed with a large laparotomy wound and uses either a transperitoneal or retroperitoneal approach. Due to the older age of this patient population, they often suffer more from the surgical wound, require prolonged hospital stay and have a slower recovery. We describe the use of hand-assisted laparoscopic surgery for grafting of a 5.5-cm infrarenal AAA identified by computed tomography scan. The operator inserted the left hand with a Pneumo Sleeve device in the abdomen through a 7-cm midline supraumbilical incision for laparoscopic surgery. Using the left hand and laparoscopic instruments to do the surgery provided control over the operation and sensation of touch. At the completion of the laparoscopic dissection, the first Clawford clamp was applied above the aortic bifurcation through the laparoscopic incision. The second Clawford clamp was applied below the renal arteries through the midline laparotomy incision. After cross-clamping the AAA, the aneurysm was incised, the clot removed, and lumbar bleeding points were oversewn with 3-O prolene suture. Then, the aneurysmal segment was grafted with a Dacron prosthesis using conventional suturing technique. The patient was extubated 3 hours after the operation, stayed in the intensive care unit for 1 night and was discharged 7 days later. He resumed oral intake on the postoperative day 1. There were no complications. This case illustrates that hand-assisted laparoscopic surgery for AAA can allow quick recovery of bowel function, quick progression to regular diet, short length of hospital stay, and probably a reduction in the total cost of care.     

A suggested classification and reappraisal of mortality statistics for ruptured atherosclerotic infrarenal aortic aneurysms

A retrospective review of 80 ruptured infrarenal abdominal aortic aneurysms with classification of the patients into clinical groups based upon the findings at laparotomy was undertaken. Patients with small hematomas confined to the area of rupture were uniformly salvaged. Those with free intraperitoneal blood almost invariably died. Intermediate groups had mortalities od 37.5 and 62.5 per cent. It is concluded that operative mortality is related to the clinical group to which the patient belongs. Attention must be focused upon the potentially salvageable intermediate groups, with regard to early laparotomy and prompt, effective proximal and distal control of the aorta before entering the retroperitoneal hematoma. Major improvements in survival have occurred with smaller ruptures but little has been achieved with larger ruptures during the past 25 years.     

Inflammatory abdominal aortic aneurysm

Between January 1976 and December 1982, 181 patients with abdominal aortic aneurysms were treated surgically, and in 13 patients the aneurysms were found to be inflammatory. Inflammatory aneurysms of the abdominal aorta (IAAA) share important characteristics with typical atherosclerotic abdominal aortic aneurysms. Diagnosis and surgical management of IAAA are distinctive which suggests that IAAA should be considered separately, as a varient of typical abdominal aortic aneurysms. IAAA occur predominantly in males. The presenting symptoms are often idiosyncratic and include severe abdominal or back pain, or both, and ureteral obstruction; the diagnosis of IAAA should be considered when these symptoms are present. Although grossly and microscopically, the perianeurysmal fibrosis resembles idiopathic retroperitoneal fibrosis, the two conditions can be differentiated. At the present time, ultrasonography and computed tomography appear to offer reliable means for diagnosing IAAA. The presence of IAAA, whether established preoperatively or discovered unexpectedly at operation, necessitate certain modifications in the surgical approach, in order to avoid injuring the duodenum and the venous structures. Most patients can be successfully treated by resection and graft replacement. Rupture of the aneurysm in IAAA appears to be less frequent than in typical atherosclerotic abdominal aortic aneurysm.     

Total laparoscopic repair for abdominal aortic aneurysm

Surgical resection and grafting have long been the standard treatment for abdominal aortic aneurysm and provide an excellent long-term outcome. However, there is tremendous impact on patients due to the surgical invasiveness. Endovascular aortic repair using stent graft was introduced in 1991. After refinement of the techniques and technology, endovascular aortic repair was approved by most health authorities and is associated with less periprocedural morbidities. In between these two extremes, some surgeons endeavored to create an alternative and perform less invasive surgeries. Hand-assisted laparoscopic aortic surgery and laparoscopic-assisted aortic surgery were introduced in 1996. In 2001, total laparoscopic abdominal aortic aneurysm resection with tube graft interposition was first performed in Canada. Till now, only a few vascular units in North America and Europe perform these delicate techniques. We report our first case of total laparoscopic abdominal aortic aneurysm repair. Laparoscopic aortic surgery provides better visualization of the aneurysm neck, less bowel manipulation and avoidance of hypothermia. The minimal invasiveness could translate to better perioperative outcome. To our knowledge, this is also the first case report in Asia. The detailed techniques are described.