Graft dilatation following abdominal aortic aneurysm resection and grafting.

BACKGROUND: It has been suggested that graft dilatation following repair of abdominal aortic aneurysm (AAA) is associated with complications such as anastomotic aneurysm and graft rupture. The purpose of the present study was to document the degree of dilatation observed in grafts after aneurysm repair and to correlate this with any graft-related complications. METHODS: Between January 1987 and December 1992, 219 patients had elective repair of their AAA at St George Hospital. A follow-up ultrasound scan was available for 154 of these patients. The following factors were examined: age, sex, size of aneurysm, type and size of graft, time of follow-up scan, size of graft at follow-up and any graft-related complications. RESULTS: The mean graft dilatation observed in knitted grafts (42.6%; 95% CI: 39.1-46.1%) was significantly greater than that observed for woven grafts (25.5%; 95% CI: 19.0-32.1%; P < 0.0001). There were no graft-related complications. CONCLUSIONS: Graft dilatation is a predictable phenomenon following AAA repair. It is more pronounced in knitted than in woven grafts, but does not necessarily lead to graft-related complications or failure.

Outpatient angioplasty: 4-year experience in one practice.

Angioplasty is often performed as an inpatient procedure after preliminary angiography. In order to increase efficiency and patient comfort we introduced a policy of performing angioplasty for chronic leg ischaemia as an outpatient whenever possible, using duplex scanning to select suitable lesions. This paper examines the safety and feasibility of this policy over a 4-year period. We prospectively assessed 168 consecutive cases which were planned for outpatient angioplasty from a total of 190 cases undergoing angioplasty and found full agreement between duplex scanning and angiography in 92%. Six patients (4%) developed complications of angioplasty requiring admission and another five were admitted for unexpected organisational reasons. Thus, the complication rate of outpatient angioplasty was 4%. All complications were noted at the time of angioplasty with no unexpected readmissions. Angioplasty for leg ischaemia is feasible and safe to perform as an outpatient using duplex scanning to select appropriate cases.

Treatment of abdominal aortic aneurysm disease in the 9th and 10th decades of life.

BACKGROUND: The appropriate management of patients who are older than 80 years of age and who present with an abdominal aortic aneurysm (AAA) remains controversial. While it appears that elective repair can be performed safely, appropriate management of these patients in the emergency situation is unclear. The purpose of the present study was to examine the results obtained in treating this elderly group in the elective and emergency setting, by operation and conservative techniques at St George Hospital, Kogarah. METHODS: Between January 1987 and December 1994 85 patients older than 80 years of age were treated for AAA. These patients were divided into four groups: I, elective presentation/no surgery; II, elective presentation/elective surgical repair; III, emergency presentation/surgical repair; and IV, emergency presentation/conservative treatment. We examined age, sex, size of AAA, mode of presentation, type of treatment, length of survival and cause of death. RESULTS: The mean age of the total group (n = 85) of patients was 84 years (range: 80-94). The mean AAA diameter for this group was 5.6 cm (95% CI: 5.2-6 cm). The diameters for group I (n = 40), II (n = 22), III (n = 16) and IV (n = 7) were 4.9 cm (4.4-5.5, 95% CI), 5.7 (4.9-6.5 CI), 7.0 (6.1-7.7 CI) and 6.2 (5.2-7.2 CI), respectively. The median survival for groups I, II, III and IV was 18, 38.5, 0.25 and 0 months, respectively. Group II had a longer survival than any other group (P = 0.015), and group IV had a shorter survival than the total group (P = 0.001). However, the length of survival was no different for III versus IV (P = 0.146). Deaths in each group were due to the following reasons. I: cardiopulmonary events (14), rupture (3), malignancy/sepsis (3); II: cardiopulmonary events (3), rupture (thoracic aneurysm) (2), malignancy (I); III: rupture (10), malignancy (I); and (IV): rupture (6), malignancy (1). CONCLUSIONS: Elective surgical repair offers the best management option for AAA in patients older than 80 years of age. Death may still occur from progression of aneurysmal disease at other sites. An aggressive surgical approach to the management of haemodynamically unstable patients in this age group is of questionable benefit.

Outcome for patients with abdominal aortic aneurysms that are treated non-surgically.

BACKGROUND: There are few reports in the literature describing the outcome for patients with abdominal aortic aneurysm who are not treated by surgical repair. This is in spite of the fact that this group of patients often defines the success of surgical treatment. The purpose of this report is to review those patients from St George Hospital Kogarah who have been rejected for surgical therapy and to examine the long-term outcome and mode of demise of these patients. METHODS: At the end of December 1992 we completed a computerized list of all patients seen at St George Hospital Kogarah with abdominal aortic aneurysm. Since that time we have continued to accrue patients to this list and obtain follow-ups prospectively. End points examined in this study were aortic aneurysm transverse diameter, sex, age, intercurrent illnesses, reasons for not undertaking surgical treatment, length of survival and cause of death. RESULTS: The mean age of patients in this series was 77 +/- 8.29 years (SD). Survival at yearly intervals for 5 years in our 101 patients were 69, 55, 44, 35 and 33%, respectively. For patients with an abdominal aortic aneurysm of < or = 5 cm, the 5-year survival rate was 42% while for patients with an abdominal aortic aneurysm of > 5 cm, the 5-year survival rate was 25%. There were 66 deaths in this series; 40% were due to cardiopulmonary events and 30% were due to ruptured abdominal aortic aneurysm. The median time between presentation and death was 12 months. CONCLUSION: The patients from this report were significantly older than those reported from previous series. We believe that it will become increasingly important to develop methods of selection of patients for current and newer modalities of treatment for abdominal aortic aneurysm. It will be increasingly important for groups offering these treatments to be able to explain to patients what their prognosis is likely to be should they not be selected for those treatments.

Sigmoid and gastric tonometry during infrarenal aortic aneurysm repair.

BACKGROUND: The value of the sigmoid tonometer in predicting sigmoid ischaemia and postoperative enteric organism infection has been reported but the value of tonometric measurement has been challenged. The purpose of this study was to examine the use of tonometric measurements in a series of patients undergoing infrarenal aortic aneurysm repair. METHODS: We assessed the results obtained when sigmoid (n=11) and gastric (n=8) tonometry were performed in patients undergoing infrarenal aortic aneurysm repair (n=11). We measured blood flow ultrasonically (n=6) in the inferior mesenteric artery(IMA) and IMA stump pressures. Sigmoid and gastric tonometry were measured prior to clamping of the infrarenal aorta, during cross clamping and after clamp release at 1, 4, 16 and 20h. Ultrasonic flow was measured before clamping. Stump pressures in the IMA were measured before, during and after clamping. RESULTS: The IMA was chronically occluded in five patients. The IMA flow was 37.5 +/- 8.7 mL/min (mean +/- s.e.). The mean IMA stump pressures before, during and after clamping were 64 +/- 13, 48 +/- 8 and 69 +/- 10 mmHg, respectively, and did not differ significantly. Mean systematic arterial pressures at these times were 89 +/- 7, 95 +/- 5 and 86 +/- 8 mmHg. These did not differ significantly or when compared with IMA stump pressure. The gradient between systemic arterial pressure and IMA stump pressure did not vary significantly at any of these times. Sigmoid and gastric intramucosal pH (pHi) did not differ significantly at any of the above times. Both sigmoid gastric pHi dropped on clamp application but 4 h afterwards had returned to baseline levels. Systemic arterial pH reflected significant ischaemia during clamping and shortly after release of the clamp(P=0.008). CONCLUSIONS: Tonometry may reflect systemic events as much as regional ischaemia. Useful tonometry results may depend on the development of a trend rather that individual measurements. The routine use of tonometry to detect intestinal ischaemia may not be cost-effective in aortic surgery.

Incidence of rupture of aortic aneurysms after coincidental operation.

The clinical course of 76 patients with aortic aneurysmal disease undergoing 107 coincidental surgical procedures was analysed in order to examine the relationship between aortic aneurysmal rupture and coincidental treatment. Additionally the incidence of aneurysmal rupture was assessed following 82 endoscopic procedures in 42 patients with aortic aneurysms. Two patients ruptured an aortic aneurysm after operation, one after colonoscopy (maximal transverse diameter 7 cm) and one after coronary artery bypass grafting (maximal transverse diameter 5.6 cm). The mean maximal transverse diameter of aneurysms in 76 patients was 5.08 cm (95% confidence interval 4.7-5.4 cm). Both patients with ruptured aortic aneurysm were outside these confidence limits and were known hypertensives whose perioperative control of hypertension was questionable. The present series of patients is discussed with reference to induction of collagenase activity as a precipitating cause for postoperative rupture of aortic aneurysms, perioperative control of hypertension, transverse aneurysm diameter as a predictor of postoperative rupture and conduct of coincidental procedures in the presence of aneurysmal disease.

Duplex scan surveillance of infrainguinal prosthetic bypass grafts.

PURPOSE: Surveillance protocols of infrainguinal vein bypass grafts have almost universal acceptance. To date corresponding studies of prosthetic grafts have not been carried out. We have performed a prospective 4-year duplex scan follow-up on polytetrafluoroethylene grafts to assess the usefulness of a surveillance program of prosthetic bypass grafts in preventing graft failure. METHODS: Over 4 years 69 infrainguinal polytetrafluoroethylene grafts in 56 patients were studied at six monthly intervals by our vascular laboratory. Full duplex scan mapping of the grafts and inflow and outflow arteries and standard ankle pressure measurements were performed. A midgraft peak flow velocity was also measured. RESULTS: Over 4 years 27 (39.1%) grafts occluded without any predictive changes in the preceding duplex scan examination. Of the 42 (60.9%) grafts that remained patent, only four developed stenoses (three at the proximal anastomosis and one at the distal anastomosis) that were amenable to intervention. Changes in ankle pressures or midgraft flow velocity did not predict failure. CONCLUSIONS: The low yield of remediable disease does not justify the cost of duplex scan surveillance of infrainguinal prosthetic bypass grafts.

The incidence of deep venous thrombosis in patients with superficial thrombophlebitis of the lower limbs.

PURPOSE: The purpose of this study was, first, to determine the incidence of underlying occult deep venous thrombosis (DVT) in patients with superficial thrombophlebitis and, second, to see if any risk factors are helpful in identifying these patients. METHODS: Forty-four consecutive patients with a clinical and duplex ultrasound-confirmed diagnosis of superficial thrombophlebitis were assessed for DVT. All patients had a duplex ultrasound study of the deep venous system. Standard thrombosis risk factors were assessed for each patient. RESULTS: Ten patients (23%) had DVT. All cases were clinically occult. One patient had propagated thrombus in the common femoral vein. Three patients had popliteal vein thrombi. The remaining patients had calf vein thrombus only. Four of these were not in continuity with the superficial thrombus. The site of the superficial thrombophlebitis was not predictive of DVT. None of the known venous thrombotic risk factors were helpful in identifying patients at risk for DVT. CONCLUSION: Noninvasive deep venous studies are recommended in all patients with lower limb superficial thrombophlebitis because of the high incidence of occult DVT. Patients with DVT can then be treated appropriately.

Ischaemic complications of graduated compression stockings in the treatment of deep venous thrombosis.

Graduated compression stockings are frequently used in the prevention of deep venous thrombosis and the treatment of venous insufficiency. Two patients are discussed who sustained ischaemic complications after application of graduated compression stockings. Review of the literature demonstrates that low cutaneous pressures significantly decrease local blood flow and that the amount of pressure exerted by graduated compression stockings increases significantly with increases in leg girth. Ischaemic complications associated with the use of these stockings also appears to be more common than previously thought and any policy of routine prescription to patients should be questioned.

Major venous thrombosis in patients with indwelling venous access catheters.

Two patients with Hickman catheters that were used for long-term venous access developed major venous thrombosis, one with superior vena caval and the other with subclavian vein thrombosis. This represented an incidence of 9% of all Hickman catheters that were inserted over two years in The St George Hospital. Staphylococcus epidermidis was cultured from blood that was sampled through the Hickman catheter in both patients; the organism was also cultured from the tip of the removed catheter in one patient. Transverse thoracic computerized tomographic scanning diagnosed the presence and the site of thrombosis as well as excluding the presence of a mediastinal tumour that was causing extrinsic compression. The catheter had to be removed in one patient; in the other patient, heparinization without removal resulted in the resolution of symptoms.

Imaging vascular grafts in vivo with Indium-111-labeled platelets. Influence of timing on image interpretation.

Platelets labeled with Indium-111 were used to visualize polytetrafluoroethylene (PTFE) bypass grafts in vivo and to quantitate platelet deposition vs. time. The grafts were inserted into the femoral and carotid arteries of dogs and were first exposed to unlabeled blood for 0 to 3 hours. They were then imaged for up to 5 days. An index of activity, designed to correct for isotope decay and changing levels of background, was used to quantitate platelet deposition. Grafts exposed to unlabeled blood for, at most, 1 hour were visible immediately. When labeled platelets were administered to the circulation after at least 2 hours, grafts became visible only after 3 days. Continuous imaging of fresh implants, showing that platelet deposition does not increase monotonically with time, was used to explain this phenomenon. The interpretation of nuclear images of synthetic grafts depends on the delay between establishing flow in the grafts and the administration of labeled platelets.

Current PTFE grafts: a biomechanical, scanning electron, and light microscopic evaluation.

Two currently available brands of PTFE grafts (Goretex and Impra) were studied in a canine femoral artery model to determine whether changes in the manufacturing processes of the two grafts, which increased their strength, had altered the biophysical properties and the histological reactivity of either graft. Both grafts were found to be similar except for differences in their suturability. Their in vivo dynamic compliances were almost identical (1.2 +/- 0.35 vs. 1.2 +/- 0.45). (Scanning electron microscopy showed endothelialization of the grafts only adjacent to the anastomoses, and light microscopy demonstrated similar degrees of histologic incorporation by the host tissues, though of slower tempo than that previously described. These results are examined and discussed with regard to the suitability of this model for characterizing new arterial prostheses of small to medium diameter.

The role of two noninvasive tests in deep venous thrombosis.

A prospective study was performed to evaluate the accuracy and usefulness of two noninvasive modalities, Doppler ultrasonography and segmental air plethysmography, in the detection of deep vein thrombosis. Over a two-year period, 211 limbs were studied among 167 patients, and the results were compared with venography. Doppler ultrasonography was found to be very accurate in detecting above-knee thrombi (sensitivity: 92.4%, specificity: 90.7%) while plethysmography was found to be much less accurate (sensitivity: 77.3%, specificity: 62.4%). The results were also assessed according to the mode of patient presentation. Doppler ultrasonography was found to be very useful in symptomatic out-patients, because of the lower incidence of calf thrombi, and less accurate in symptomatic inpatients and in high risk in-patients being screened. The clinical usefulness of noninvasive detection of venous thrombosis is discussed with regard to the incidence of disease and the site of thrombosis in different patient groups under study, and recommendations are made based on these results.

Vein grafts to the peroneal artery.

A series of 58 consecutive vein grafts to the peroneal artery is reviewed. The grafts were part of a total series of 144 attached to the tibial and peroneal vessels over a 10-year period for advanced ischemia. The initial salvage rate was 86%, the operative mortality rate was 3.4%, and cumulative patency rates at 12 and 36 months were 69.4% and 50.6%, respectively. The indications for the operation, techniques employed, and results are considered. The peroneal artery has valuable potential in the revascularization of the severely ischemic lower limb.

Single-dose parenteral antibiotics as prophylaxis against wound infections in colonic operations.

A study of 77 patients undergoing elective operations on the colon and rectum, where wounds were subject to contamination by fecal flora, did not demonstrate that the addition of a preoperative oral regime to parenteral antibiotics alone further decreased the incidence of wound infection. The authors feel that the use of single-dose clindamycin and cephazolin intravenously preoperatively has been shown to be a very effective method of preventing wound infection in elective colonic resections.