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Biomedical subjects

R D Sayers

Publications and source records attributed to R D Sayers.

At least 73 records · Page 4Linked to original sources
PubMed1997

Surgical management of 671 abdominal aortic aneurysms: a 13 year review from a single centre.

OBJECTIVE: To audit the results for abdominal aortic aneurysm (AAA) repair from a single centre over a 13 year period. DESIGN: Retrospective survey. SETTING: Vascular unit of a major teaching hospital. MATERIALS: Six hundred and seventy-one consecutive patients divided into two groups: group A (1981-87) and group B (1988-93). CHIEF OUTCOME MEASURES: Mortality rates, cause of death and major complications in patients undergoing elective, urgent and ruptured AAAs. RESULTS: Elective repair was performed in 313 (47%) patients, urgent repair in 80 (12%) and emergency repair for rupture in 278 (41%). A vascular surgeon performed the procedure in 94% of patients. The overall mortality was 21 patients in the elective group (6.7%), 13 in the urgent group (16%) and 148 in the ruptured group (53%). Mortality rates have not fallen during the study period but more patients in group B had ischaemic heart disease. Sixty patients (9%) required further operative procedures on 66 occasions: 24 elective cases (8%), 8 urgent cases (10%) and 28 ruptured cases (10%). There were 23 deaths in these 60 patients (38%) who underwent re-operation (5 elective, 2 urgent and 16 ruptured). Major postoperative complications included cardiac events in 212 (32%) patients, respiratory failure in 202 (30%) and renal failure in 90 (13%). Major causes of death included cardiac disease in 67 patients (37%), cardiac disease with coagulopathy in 22 (12%) and cardiac disease with respiratory failure in 16 (9%). Logistic regression analysis showed that in the elective group, cardiac or renal failure were significantly associated with death; and in the ruptured group cardiac, respiratory or renal failure were significantly associated with death. CONCLUSIONS: More high risk patients with ischaemic heart disease are undergoing AAA repair. Postoperative cardiac, respiratory or renal failure are significant causes of death in AAA patients.

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PubMed1997

Ultrasound-based quantification of emboli during conventional and endovascular aneurysm repair.

PURPOSE: To differentiate and quantify the type and number of lower limb emboli occurring during endovascular aneurysm repair, as compared to conventional surgery. METHODS: Thirty-eight patients underwent elective infrarenal aneurysm repair using a conventional surgical approach in 18 and an endovascular procedure in 20. Emboli were detected using a Doppler ultrasound system with a 2-MHz transducer interrogating the mid superficial femoral artery. Lower limb emboli were differentiated as particulate or gaseous based on the physical distance traversed by the embolic signal. RESULTS: Significantly more particulate (median 108 versus 59, p = 0.015) and gaseous (134 versus 46, p = 0.008) emboli were detected during endovascular aneurysm repair as compared to conventional surgery. Clinically, no case of massive microembolization occurred in either group, but one patient in the conventional group required a femoral embolectomy, and three patients undergoing endovascular repair developed self-limiting trash feet postoperatively. In patients undergoing endovascular aortomonoiliac aneurysm repair, there was only a poor correlation between the number of particulate emboli and either procedural duration or operator experience. CONCLUSIONS: The apparent lack of a relationship between particulate embolization and operative time or technical experience suggests that manipulation of endoluminal devices within the aneurysm sac may not be the sole determinant of intraprocedural embolization. Other as yet undetermined factors may predict patients at high risk for massive embolization.

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PubMed1997

Improved respiratory function and analgesia control after endovascular AAA repair.

PURPOSE: Endovascular abdominal aortic aneurysm (AAA) repair has been proposed as a minimally invasive alternative to conventional surgery and may offer significant advantages in respiratory function and analgesic requirements due to the absence of an abdominal incision. METHODS: Respiratory function and analgesic requirements were quantified in 22 age-matched patients undergoing aneurysm repair under general anesthesia. Twelve patients underwent endovascular aneurysm repair, while 10 AAA patients had conventional surgery. One endovascular patient required conversion to conventional repair. RESULTS: The endovascular group required postoperative artificial ventilation for a shorter time (6 versus 21 hours, p < 0.05) and had lower PCA (patient-controlled analgesia) morphine consumption (41 versus 133 mg, p < 0.05) than the conventional group. The endovascular group also had significantly better forced expiratory volume and forced vital capacity at both 3 and 5 days when expressed as percentages of the preoperative values (p < 0.05). CONCLUSIONS: Endovascular AAA repair attenuates respiratory dysfunction associated with conventional surgery and reduces perioperative analgesia requirements.

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PubMed1997

Aortomonoiliac endovascular grafting: difficult solutions to difficult aneurysms.

PURPOSE: To describe a refined technique for aortomonoiliac endograft exclusion of abdominal aortic aneurysms (AAAs). METHODS: A tapered aortomonoiliac graft was prepared from an 8-mm thin-walled expanded polytetrafluoroethylene tube graft predilated proximally to 35 mm and tapered distally to 15 mm. The proximal graft was sutured to a 5-cm-long, predilated Palmaz stent, which was mounted on a 30-mm balloon and backloaded into a 21F packaging sheath. With the patient under general anesthesia and both common femoral arteries exposed, the endograft was anchored in the infrarenal aorta and subsequently passed into one iliac system, where it was anastomosed to the iliac or femoral vessels. The contralateral common iliac artery was occluded, and an extra-anatomic, femorofemoral, or iliofemoral bypass grafting was performed. RESULTS: Twenty of the 25 AAAs treated to date with this technique have been successful, with aneurysm exclusion achieved in 18 (2 minor distal endoleaks are scheduled for endovascular repair). The technical failures were analyzed, resulting in enhancements to the technique. Complications included 2 early (< 30 days) deaths, 1 case of minor embolization, 1 transient renal failure, 1 pulmonary embolus, and 1 wound infection. The only late complication was a graft infection localized to the groin. CONCLUSIONS: Aortomonoiliac endovascular aneurysm repair is effective in patients with AAAs involving the iliac arteries. Short-term results are acceptable, but long-term efficacy must be addressed before this procedure is widely adopted. Technical changes made in response to early learning curve problems have led to a safer, more reliable procedure.

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PubMed1997

Surgical decompression of thoracic outlet syndrome; is it a worthwhile procedure?

During a 20-year period from 1974 to 1994, 37 thoracic outlet decompressions were performed. There were 28 females and six males (ratio 5:1). The median age was 37 years (range 15-64). Symptoms were predominantly neurological in 29 limbs (78%), arterial in five limbs (14%) and venous in three limbs (8%). Limb pain and paraesthesia were the most common symptoms. Surgical decompression was performed via a supraclavicular approach in 24 limbs (65%) and a transaxillary approach in 13 limbs (35%). A cervical rib was excised in 21 limbs (57%), a first rib in 10 limbs (27%), a cervical and first rib in one limb (3%) and a cervical band in five limbs (13%). Arterial reconstruction was only required in three limbs (8%). There were a total of four complications (11%). The outcome of surgical decompression was assessed by using a questionnaire completed by the patient. Overall 27 patients (87%) felt that the operation was worthwhile. These results show that surgical decompression for thoracic outlet syndrome is a worthwhile procedure and is associated with relatively few complications.

Adolescent↗
PubMed1996

Endovascular repair of abdominal aortic aneurysm: an initial experience.

Endovascular repair of abdominal aortic aneurysm (AAA) was attempted in ten patients over a 12-month period. Median age was 72 (range 61-82) years and median AAA diameter was 5.5 (range 5.2-6.0) cm. An aortoaortic (tube) graft was used in seven patients and a tapered aortoiliac reconstruction in three. There were two failures requiring conversion to open repair. Additional procedures included iliac artery angioplasty (two), coil embolization of an associated common iliac aneurysm (one) and femorodistal bypass (one). Median operating time was 162 (range 95-270) min and median blood loss was 1200 (range 800-2000) ml. Median hospital stay was 9 (range 5-21) days. Complications included death (one), reversible acute tubular necrosis (one) and prolonged ventilation (one). Postoperative evaluation with duplex ultrasonography and computed tomography demonstrated three perigraft leaks (two proximal and one distal). It is concluded that endovascular repair of AAA is feasible but is associated with significant complications and requires careful evaluation before widespread use.

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PubMed1996

Elastase-induced matrix degradation in arterial organ cultures: an in vitro model of aneurysmal disease.

PURPOSE: Abdominal aortic aneurysms are characterized by degradation of the extracellular matrix, induction of endogenous metalloproteinases (MMPs), and development of a chronic inflammatory infiltrate. Despite intensive analysis of end-stage tissue, aneurysm pathogenesis remains obscure. The aim of this study was to develop an in vitro model of aneurysmal disease. METHODS: Porcine aortic organ cultures were preincubated with pancreatic elastase before culture in standard conditions for up to 14 days. The extent of matrix degradation at various time points was determined by quantitative histologic estimation of collagen and elastin concentration. Endogenous metalloproteinase production within the tissue was quantified by gel enzymography and immunoblotting. A separate series of experiments was performed to investigate the effect of incorporating autologous leukocytes into the culture system. RESULTS: Although exogenous elastase was removed after 24 hours, substantial degradation of the aortic extracellular matrix occurred in the subsequent 13 days in tissue culture. Analysis of samples preincubated with elastase (100 U/ml) for 24 hours before tissue culture demonstrated that elastin degradation occurred in a time-dependent manner (p < 0.001) and was not confined to the initial phase of exogenous elastase activity. Gelatin gel enzymography revealed a time-related production of metalloproteinases (55 to 250 kDa) within the aortic tissue. The presence of MMPs-1, 2, 3, and 9 was determined by immunoblotting. Immunohistochemistry identified the vascular smooth-muscle cell as the source of MMPs-1, 2, and 3. Addition of autogenous leukocytes to elastase-pretreated tissue initiated an inflammatory infiltrate within the aortic wall, which further enhanced both matrix degradation and MMP production (p < 0.001). CONCLUSIONS: These data demonstrate that aortic samples pretreated with elastase before tissue culture undergo matrix degradation with MMP production and the development of an inflammatory infiltrate. These changes mirror the pathophysiological events within established aneurysms. It is suggested that this model may be useful in understanding early pathogenic events within aneurysmal tissue.

Animals↗
PubMed1996

Femorofemoral crossover grafts for claudication: a safe and reliable procedure.

OBJECTIVE: To evaluate the role of femorofemoral crossover grafts in patients with disabling claudication. DESIGN: Retrospective study. SETTING: University hospital. MATERIALS: Two hundred and eleven patients with iliac artery disease undergoing femorofemoral crossover grafts for disabling claudication. CHIEF OUTCOME MEASURES: Perioperative mortality, follow-up cumulative graft patency, limb loss, survival, graft infection and false aneurysm formation were evaluated to determine the immediate and long-term outcome of the procedure. MAIN RESULTS: Primary and secondary graft patency at 5 years was 72% and 89% respectively. There were no perioperative deaths (zero 30 day mortality). Dacron was used in 66 patients (31%) and PTFE in 145 (69%). There were no differences in patency between the two graft materials but eight Dacron grafts (12.1%) were removed because of complications (false aneurysm or infection) compared to four PTFE grafts (2.7%) (p < 0.001 Chi-square). Five patients (2%) have undergone a major lower limb amputation. Forty-one patients (19%) have required subsequent inflow procedures which represents a cumulative need for inflow of 5% per year. CONCLUSIONS: Femorofemoral crossover grafts are a safe and reliable procedure in patients with disabling claudication caused by unilateral iliac artery disease.

Adult↗
PubMed1996

The effect of a surveillance programme on the patency of synthetic infrainguinal bypass grafts.

OBJECTIVES: Vein graft surveillance is widely acknowledged to be of benefit in improving graft patency at least in the first year after arterial bypass surgery. The aim of this study was to examine the effect of a surveillance programme on the patency of synthetic infrainguinal bypass grafts. DESIGN: A prospective study of 69 consecutive prosthetic bypass grafts was undertaken over a 3 year period. METHODS: Patients were seen at 3 monthly intervals after surgery and underwent measurement of ankle brachial pressure indices and a colour Duplex scan of the graft. RESULTS: The surveillance programme was able to detect treatable lesions in five grafts and in the run-off vessels of two other grafts prior to occlusion. However 14 grafts failed after the first 30 days, 12 of which were not predicted by the surveillance programme. CONCLUSIONS: Surveillance appears to be of limited benefit in the maintenance of patency of synthetic infrainguinal bypass grafts.

Aged↗
PubMed1996

Angiogenesis in abdominal aortic aneurysms.

OBJECTIVES: To determine the degree of neovascularisation in the wall of abdominal aortic aneurysms in comparison to atherosclerotic control aortas, and to correlate the angiogenic response with the extent of the cellular inflammatory infiltrate. DESIGN: Histopathological study. MATERIALS: Aortic samples were obtained from patients with abdominal aortic aneurysms and from atherosclerotic controls. METHODS: Samples were stained with haematoxylin and eosin, and Miller's elastin and Van Gieson stain, EVG, and a monoclonal antibody specific to human endothelial cells. Within the aortic wall three histological regions were defined, the media, the adventitia and a transition zone. The number of capillary like, thin walled vessels were measured in each region, and the cellular infiltrate was quantified. RESULTS: The number of newly formed vessels was increased in all layers of aneurysmal wall in comparison to control samples (p<0.001). The degree of neovascularisation correlated with the extent of the inflammatory infiltrate (rs=0.45, p<0.01). CONCLUSIONS: This study demonstrated that abdominal aortic aneurysms are associated with a marked angiogenic response, which is related to the degree of inflammation within the aortic wall. It is hypothesised that anti-angiogenic agents may play a role in the medical management of aortic aneurysmal disease.

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PubMed1996

Oxygen free radical and cytokine generation during endovascular and conventional aneurysm repair.

OBJECTIVES: Endovascular aneurysm repair has been proposed as a "minimally invasive" alternative to conventional aneurysm resection. One of the most important potential benefits of endoluminal surgery is the avoidance of aortic cross clamping, which may attenuate the ischaemia-reperfusion injury that complicates open aneurysm repair. This study aimed to quantify the metabolic response to both conventional and endovascular aortic surgery. DESIGN: Prospective clinical study. SETTING: University hospital. METHODS: Femoral vein blood samples (pre-clamp, during aneurysm repair and 5 and 30 min post reperfusion) were obtained from 12 patients undergoing aortoaortic aneurysm repair, six by conventional transperitoneal inlay replacement (median age 71 years, median aneurysm diameter 5.8 cm), and six by endoluminal deployment of a straight endograft (median age 73 years, median aneurysm diameter 5.5 cm). All endovascular procedures were completed satisfactorily with no conversions to conventional surgery. OUTCOME MEASURES: Venous blood samples were analysed for oxygen free radical (OFR) production using the quantifiable oxidation of IgG in plasma, and cytokine (IL-1 beta and TNF-alpha) generation by radioimmunoassay. [table: see text] RESULTS: The results are given as median values with interquartile ranges: CONCLUSIONS: These results suggest that the ischaemia-reperfusion response associated with conventional aneurysm surgery may be largely negated by endovascular techniques. This may have significant consequences as the generation of oxygen free radicals and cytokines have been implicated in the development of systemic organ failure following aortic surgery.

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PubMed1996

Proximal stent deployment without contrast during endovascular aneurysm repair: an improved technique.

PURPOSE: To describe a technique to enhance stent visibility on the fluoroscopic monitor during aortic endograft deployment. TECHNIQUE: To assist in accurate positioning and deployment of the proximal stent in a Parodi-type aortic endograft, the stent is affixed to the balloon so that the radiopaque marker sits at the stent's distal end. When the device is in position and the sheath is retracted, the stent and the radiopaque balloon markers are clearly seen on the fluoroscopic image. Using normal saline only to inflate the balloon allows the stent to remain visible throughout deployment. CONCLUSIONS: The use of saline rather than contrast medium for balloon inflation provides continuous visualization of the stent during expansion, thus facilitating accurate deployment and early recognition of balloon migration within the stent.

Angioplasty, Balloon↗
PubMed1995

Percutaneous transluminal angioplasty for lower-limb critical ischaemia.

Percutaneous transluminal angioplasty (PTA) alone was used to treat 54 (23 per cent) of 232 lower limbs with critical ischaemia. Technical success was achieved in 49 cases (91 per cent) with an immediate symptomatic improvement in 47 (87 per cent). There was no death or limb loss attributable to PTA and three embolic complications were successfully treated by percutaneous aspiration. Symptomatic improvement and haemodynamic patency rates at 24 months were 77 and 78 per cent respectively; 27 of 34 limbs with ulceration or gangrene had healed with minor surgery by a median of 7.5 (range 3.0-18.0) months. Patient survival and limb salvage rates at the same time interval were 76 and 89 per cent respectively. These results demonstrate that, for a selected group of patients with lower-limb critical ischaemia, PTA can be a highly successful therapeutic option with a low associated morbidity.

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