Canadian human resource needs in vascular surgery

OBJECTIVE

To outline the distribution of vascular surgeons in Canada and to determine the present and future human resource needs in vascular surgery practice in Canada.

DESIGN

Voluntary questionnaires sent to all members of the Canadian Society for Vascular Surgery (CSVS), the administrators of hospitals in Canada with more than 100 beds, and interrogation of the membership database of the CSVS.

MAIN OUTCOME MEASURES

The perceived present and future needs for full-time and part-time vascular surgeons, determined by a variety of methods.

PARTICIPANTS

One hundred and forty active members of the CSVS and administrators of 120 hospitals.

MAIN RESULTS

From the CSVS members 62 responses were received from those residing in Canada, revealing 47 full-time vascular (more than 75% of the practice) surgeons working with 0 to 5 colleagues (mean 1.8 [SD 1.3]). Fifteen responding surgeons combined the practice of vascular surgery with another specialty. Perceived immediate needs were 24 surgeons, with 42 required in 4.8 (1.8) years. Of 120 hospitals offering vascular surgery services, 90 stated that they met the needs of their community; however, additional immediate manpower requirements totalled 27 surgeons. Hospital administrators predicted a need of 55 additional vascular surgeons in a mean of 5.5 (4.6) years. Over 85% of hospitals stated that they had the resources to support the currently practising surgeons and their immediately required additions.

CONCLUSIONS

Prediction of the need for additional vascular surgeons should be based on an estimated retirement age of 65 years, with an adjustment for the increasing percentage of the Canadian population reaching the age of 60 years. All methodologies used in this study predict the need for additional human resources in vascular surgery. The need for continued training of new vascular surgeons is apparent, but the optimal number of trainees per year is less clear.

Preferences of program directors for evaluation of candidates for postgraduate training

OBJECTIVE

To determine the preferences of program directors for various grading systems and other criteria in selecting students for residency training positions through the Canadian Resident Matching Service (CaRMS).

DESIGN

Questionnaire survey.

PARTICIPANTS

All 110 directors of residency training programs in Ontario.

SETTING

Ontario medical schools.

OUTCOME MEASURES

Weighting of importance of different screening tools (e.g., grading systems, personal interview, dean's letter) used during undergraduate training.

RESULTS

Of the 110 directors 96 (87%) responded. Of the 92 who rated the various grading practices 35 (38%) preferred a numeric grading system, 26 (28%) a letter grading system, 23 (25%) an honours/pass/fail system and 8 (9%) a pass/fail system. Most of the respondents from each school favoured a grading system that was more discriminating than the one used at their location. The personal interview was regarded as the most important screening tool by 80 (83%) of the respondents; the dean's letter was considered to be very useful by only 16 (17%).

CONCLUSIONS

More value was placed by program directors on a numeric or other more discriminating grading system than on the pass/fail system. Although the grading system provides only one type of screening mechanism it raises the question of whether there should be a policy for uniform grading practices for all Canadian students.

Vascular injury and repair associated with retroperitoneal lymphadenectomy for nonseminomatous germinal cell tumours of the testis

Metastatic disease adjacent to major vascular structures in the retroperitoneum sometimes necessitates planned removal of portions of these vessels, or the vessels may inadvertently be injured when retroperitoneal lymphadenectomy is performed. In 78 patients who underwent retroperitoneal lymphadenectomy, 17 (22%) required vascular repair intraoperatively. The vena cava was most frequently involved (eight cases) followed by inadvertent injury to the renal arteries (five cases) or the infrarenal aorta (three cases). Resection of the infrarenal aorta was planned in two cases without postoperative complication. In six cases a resection of either the whole inferior vena cava or a portion of it was needed to remove all of the tumour. There were nine cases of inadvertent injury to the aorta, vena cava or a renal artery. The outcome after arterial repair was satisfactory with the exception of the inadvertent renal artery injuries, which required nephrectomy in three cases. Leg swelling was not a long-term sequela of either caval repair or resection.

End-to-end versus end-to-side proximal anastomosis in aortobifemoral bypass surgery: does it matter?

The proximal anastomosis is still a controversial issue in vascular surgery. To compare end-to-end (EE) and end-to-side (ES) proximal anastomoses, the authors undertook a prospective study with 3 years' follow-up involving 120 patients, all of whom had aortobifemoral bypass. Fifty-one (42.5%) patients received the EE and 69 (57.5%) the ES anastomosis. The indications for surgery were abdominal aortic aneurysm (EE 51%, ES 0%; p less than 0.05), claudication (EE 33.3%, ES 53.6%; p less than 0.05) and critical ischemia (EE 15.7%, ES 46.4%; p less than 0.05). Patients in the EE group were older (mean age: EE 66.1 +/- 2.8 years, ES 60.9 +/- 1.1 years; p less than 0.05) and had more ischemic heart disease (EE 39.2%, ES 27.5%; p less than 0.05). Postoperative mean increases in transcutaneous oximetry (EE 15.5 +/- 3.9 mm Hg, ES 12.6 +/- 2.3 mm Hg) and the ankle-brachial pressure index (EE 0.34 +/- 0.05, ES 0.30 +/- 0.03) were not significantly different in the two groups. The operative death rate was higher for the EE group (EE 11.8%, ES 1.4%; p less than 0.05). Early thrombosis occurred in six patients, two in the EE group and four in the ES group. Computed tomography, done 1 year postoperatively in 95 patients, revealed two small (less than 3 cm) distal anastomotic dilatations, one in each group. At 3 years, cumulative survival and patency were similar in both groups. The authors conclude that the two anastomotic groups had very similar short- and long-term results, except for the operative death rate which was higher in the EE group.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of central haemodynamic monitoring in abdominal aortic surgery. A prospective randomised study

To test the hypothesis that central haemodynamic monitoring is not necessary in all patients undergoing abdominal aortic surgery, a prospective randomised study in 40 consecutive patients undergoing elective abdominal aortic surgery was carried out. Patients with unstable angina, recent myocardial infarction (less than or equal to 6 months), and left ventricular ejection fraction (LVEF) less than 0.50 were excluded. Twenty-one patients had perioperative central haemodynamic monitoring while 19 patients had central venous pressure monitoring alone. Parameters studied included, perioperative haemodynamics and fluid balance, perioperative cardiac drug administration, operation time and clamp time, postoperative renal function, incidence of postoperative ventilation and line complications, duration of hospital and ICU stay, and 30 day postoperative outcome. Results obtained were compared with a high risk group of patients (LVEF less than 0.50) undergoing similar surgery. Statistical analysis failed to show any difference in outcome for any variable measured in either low risk group. All serious postoperative cardiac complications occurred in patients with LVEF less than 0.50 (P less than 0.0001). These data suggest that patients with LVEF greater than or equal to 0.50 are at low risk of developing postoperative cardiac complications and can be successfully managed perioperatively without the added potential risks and costs of central haemodynamic monitoring.

Is tube repair of aortic aneurysm followed by aneurysmal change in the common iliac arteries?

To address the concern that tube repair of an abdominal aortic aneurysm might be followed by aneurysmal change in the common iliac arteries, 23 patients who had undergone the operation were re-examined 3 to 5 years later. Although 9 had had minimal ectasia of these arteries preoperatively, in none of the 23 was there symptomatic or radiologic evidence of aneurysmal change on follow-up. Measurements of the maximum intraluminal diameters were made by computed tomography; they indicated no significant differences between the preoperative and follow-up sizes of the common iliac arteries. The variation in time to follow-up also showed no significant correlation with change in artery diameter.

The influence of central haemodynamics on transcutaneous oxygen (TcpO2) measurements

Transcutaneous oxygen measurements (TcpO2) have been shown to be an index of tissue perfusion and it has been suggested that the main haemodynamic variable influencing tissue perfusion is cardiac output, assuming that inspired oxygen remains constant. To investigate this hypothesis we studied 23 consecutive patients in order to identify if changes in cardiac output correlated with similar changes in TcpO2 measurements. No correlation was found to suggest that cardiac output was the main haemodynamic determinant of TcpO2 measurements.

The effect of femoral arteriography on the incidence of groin contamination and postoperative infections

A prospective study is presented on the effects of preoperative femoral arteriography on bacterial contamination and postoperative wound complications from groin incisions. Forty-four femoral reconstructive procedures (88 groin incisions) for aortoiliac disease were performed. Positive cultures occurred in 43.2% of patients and in 30.7% of the 88 incisions. There was no correlation found between the site of arteriography and positive cultures (Spearman correlation coefficient, p greater than .10). No correlation was found between the presence of hematoma due to arteriography and subsequent positive groin culture (Spearman correlation coefficient, p greater than .10). A higher incidence of positive cultures did occur for patients who had a difficult arteriographic procedure (Fisher's exact test, p = .020) or whose reconstructive procedure was greater than four hours (Fischer's exact test, p = .047). Seven patients had postoperative groin wound complications (15.9%), including three lymph leaks (6.8%) and four confirmed or suspected infections (9%). There were no graft infections. No correlation was found between the site of arteriography and the site of wound complication (Spearman correlation coefficient, p greater than .10). Neither positive culture results nor difficult arteriography nor presence of hematoma were accurate predictors of postoperative wound complications. We conclude that transfemoral arteriography does not increase the risk of complications of arterial reconstruction involving a femoral anastomosis.

Failure of bicycle exercise electrocardiograms to predict major post-operative cardiac complications in patients undergoing abdominal aortic surgery

To determine if exercise electrocardiograms (EECGs) are justified in routine pre-operative screening for cardiac disease, we performed a prospective study on 77 consecutive patients scheduled for infrarenal aortic reconstructive surgery. All patients had EECGs performed 1-12 days prior to elective surgery. In addition to routine clinical assessment of cardiac disease, all patients were allocated a Goldman risk score. Four patients developed major post-operative cardiac complications of whom one patient died. EECG was not a significant predictor of outcome, as 48.6% of all EECGs were inadequate due to non-completion of the exercise protocol. Significant pre-operative predictors of outcome were a history of angina (p less than 0.01), myocardial infarction (p less than 0.001), congestive cardiac failure (p less than 0.0001), or a Goldman score of greater than 14 (p less than 0.05). By multivariate analysis of the pre-operative risk factors a history of congestive cardiac failure was found to be the most significant independent predictor of post-operative cardiac complications.

Predictors of surgical outcome in patients undergoing aortobifemoral bypass reconstruction

We report a prospective study with 2 years of follow-up including 105 consecutive symptomatic patients (58.1% claudication and 41.9% severe ischemia) undergoing aortobifemoral bypass surgery (ABF/BP). Proportional-hazards, stepwise regression, and life-table analyses were used to determine predictors of the following outcome criteria: graft patency, amputation, mortality, symptomatic recurrence, and palliation. The operative mortality was 5.7% and the 2-year cumulative mortality was 15.5%. Most deaths (61.5%) were cardiac-related. There were 3 predictors of mortality: the presence of more than 1 surgical risk factor (relative risk [RR] 6.2; p less than 0.001), advanced age (RR 2.9; p = 0.03) and the presence of ischemic heart disease (RR 1.5; p = 0.045). No patient required amputation. Early graft patency rate was 94.3% and the 2-year cumulative patency was 92.8%. The only predictor of graft failure was preoperative ankle/brachial index (ABI) of less than 0.4 (RR 6.1; p = 0.003). Early symptomatic relief was 98.1% and at 2 years it was 77.3%. There were 2 predictors of symptomatic recurrence: postoperative smoking (RR 2.4; p less than 0.001) and impaired runoff (RR 2.5; p = 0.017). Cumulative palliation was 87.6% at 1 month and 66.5% at 2 years postoperatively. There were 2 predictors of palliation: the presence of more than 1 surgical risk-factor (RR 1.8; p = 0.001) and postoperative transcutaneous oximetry (PtcO2) of less than 35 mmHg (RR 3.1; p = 0.04). We conclude that the best predictors of outcome in patients undergoing ABF/BP surgery were the number of preoperative risk factors, age, ischemic heart disease, ABI, PtcO2, postoperative smoking, and angiographic runoff.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison between transcutaneous oximetry and ankle-brachial pressure ratio in predicting runoff and outcome in patients who undergo aortobifemoral bypass

In a prospective study, transcutaneous oxygen tension and ankle-brachial pressure index (ABI) were measured pre- and postoperatively in 105 symptomatic patients who underwent aortobifemoral bypass to compare the ability of these two measurements to reflect the runoff status, determined by angiography, and to predict the outcome of surgery. Postoperatively, ABI better reflected the runoff status. The difference in mean ABI for good versus poor runoff was 0.17 (p less than 0.05). The difference in mean transcutaneous oxygen tension below the knee for the two runoff categories was relatively small (6.3 mm Hg, p less than 0.05). Post-minus preoperative increases in ABI reflected the runoff status better than increases in transcutaneous oxygen tension. For good runoff, the mean ABI increase was 0.25 and for poor runoff it was only 0.14 (p less than 0.05). Runoff and transcutaneous oxygen tension were found to be the best predictors of symptomatic recurrence. Poor runoff was associated with a relative risk of 2.5 (p = 0.017) and transcutaneous oxygen pressure of less than 40 mm Hg implied a relative risk of 2.3 (p = 0.029) for symptomatic recurrence. The most important predictor of graft failure was preoperative ABI. Transcutaneous oxygen tension and the ankle-brachial pressure index appear to be valuable noninvasive techniques for vascular assessment, offering different insights and different predictions for management and prognosis of peripheral vascular disease.

Percutaneous transluminal angioplasty without anticoagulation

This paper presents the results of a retrospective study of 110 percutaneous transluminal angioplasties done over a period of two years on 110 consecutive patients. Anticoagulation or antiplatelet drugs were not used during or after percutaneous transluminal angioplasty. Life-table analysis was used to calculate success rates at one and three months following the procedure. Success rates were determined using three criteria: clinical improvement, pre- and post-percutaneous transluminal angioplasty Doppler studies, and radiographic appearance. Claudication was present in 87 (79%) patients and severe ischemia in 23 (21%) patients. Sixty-eight (62%) PCTAs were done in the iliac arteries, 35 (32%) in the femoral arteries, and 7 (6%) in the popliteal artery. The majority of patients (61%) had 50%-75% arterial stenosis and only 18% had complete occlusion. Percutaneous transluminal angioplasty in the iliac arteries had the best results with cumulative success rates of 90% and 85% at one and three months, respectively. Success rates in the femoral arteries were 83% and 79% and in the popliteal artery 71% and 57% at one and three months, respectively. None of our patients required amputation. Ten patients (9.1%) suffered the following complications within 30 days of percutaneous transluminal angioplasty: death (2), thrombosis (2), perforation (3), minor hematoma (2), and false aneurysm (1). In conclusion, we have shown that percutaneous transluminal angioplasty can be performed safely and effectively without the use of anticoagulation and its associated risks.

Effects of cigarette smoking on outcome of femoral popliteal bypass for limb salvage

A retrospective 5-year follow-up study of 83 femoral-popliteal bypass operations for severe ischemia (79 patients) is presented. There were no operative deaths. At one month, cumulative patency rates (CPR) and limb salvage rates (LSR) were 86.8% and 96.4% respectively. At 5 years, CPR, LSR and cumulative survival were 50%, 79.4% and 71.6% respectively. Post-operative smoking habits were strongly related to CPR and LSR. Smoking more than 5 cigarettes per day adversely affected CPR's. At 5 years, CPR of non-smokers and smokers of up to 5 cigarettes per day (47 patients) was 67.7% and for smokers of more than 5 cigarettes per day (32 patients) it was 44.7% (P less than 0.045). Smoking more than 15 cigarettes per day had an adverse effect on LSR's. Smokers of more than 15 cigarettes per day (17 patients) had a 5-year LSR of 58.5% compared with 89% for non-smokers and smokers of up to 15 cigarettes per day (62 patients) (P = 0.009). For 20 limbs requiring thrombectomy LSR was 100% at 1 year and 57.5% at 5 years. CPR's and LSR's were not significantly influenced by pre-operative smoking, diabetes, run off or level of distal anastomosis relative to the knee joint. Based on zero operative mortality and 96.4% limb salvage at 1 year, it is concluded that an aggressive approach toward revascularization for limb salvage is well justified in most patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Selection of amputation level and prediction of healing using transcutaneous tissue oxygen tension (PtcO2)

Pre-operative measurement of transcutaneous tissue oxygen tension (PtcO2) by reflecting oxygen delivery at proposed amputation sites may allow accurate prediction of post-operative healing. Thirty-eight patients requiring amputation had PtcO2 measured with a Clark electrode on the foot, anteriorly and posteriorly below knee and above the knee while lying supine. PtcO2 greater than 24 mmHg was chosen to predict healing and indicated 13 above-knee (AK) and 25 below-knee (BK) amputations. Clinical criteria indicated 12 AK and 26 BK amputations. PtcO2 and clinical judgement differed on five occasions, a lower amputation was indicated by PtcO2 twice and by clinical selection three times (PtcO2 16 mmHg). Amputation was performed at the more distal level indicated (25 BK, 13 AK). Foot PtcO2 in both groups did not differ significantly, 4.08 +/- 2.00 mmHg (BK) and 3.9 +/- 1.29 mmHg (AK) (p greater than 0.5), nor did above knee PtcO2 (p greater than 0.3). Anterior below knee PtcO2 in both groups differed significantly, 34.92 +/- 10.84 mmHg (BK) and 9.5 +/- 5.60 mmHg (AK) (p less than 0.001). Likewise, posterior PtcO2, 39.64 +/- 6.85 mmHg (BK) and 14.1 +/- 4.43 mmHg (AK) (p less than 0.001). Amputation sites healed primarily within two weeks except the site with a pre-operative PtcO2 of 16 mmHg, where healing was delayed and occurred by second intention. These results indicate that PtcO2 is a valid predictor of primary healing following amputation.

The effect of postoperative smoking on femoropopliteal bypass grafts

Effect of smoking habits on limb loss rates and cumulative patency rates of 136 arterial reconstructions performed for lower limb ischemia were analyzed in a five year follow-up retrospective study. Of 121 patients, 103 (85%) smoked before the operation and 43 of the smokers (42%) discontinued smoking postoperatively. Patients who continued to smoke more than 15 cigarettes per day (34 patients) increased the probability of losing their limb approximately five times at two years and three times at five years postoperatively, compared with nonsmokers and smokers of up to 15 cigarettes per day (87 patients) (p = 0.013). Cumulative patency rates of nonsmokers and smokers of up to five cigarettes per day (Group A, 66 patients) were not significantly influenced (p = 0.518) by preoperative symptoms (claudication versus limb salvage). However, for smokers of more than five cigarettes per day (Group B, 55 patients), at five years claudicants had a cumulative patency rate of 62.9% compared to 38.3% for limb salvage patients (p = 0.015). In group A at five years, autologous saphenous vein grafts had a cumulative patency rate of 74.2%, compared to 24% for prosthetic grafts (P = 0.013). In group B the CPR differences between autologous saphenous vein and prosthetic grafts were not significantly different (p = 0.394). Multiple interactions between smoking and variables like age, preoperative symptoms, and graft material demonstrate the complexity of the effects of smoking on cumulative patency rate and the need for sub-grouping and removal of confounding factors. In view of the adverse affects of continued smoking on postrevascularization prognosis, patients should be strongly advised to discontinue smoking.

A statistical assessment of the dependability of transcutaneous tissue oxygen tension measurements

Transcutaneous oxygen tension measurements (PtcO2) were obtained for subjects in two groups: peripheral vascular patients (N = 15) and disease-free controls (N = 9). Readings were taken in each of three locations, arm, knee and foot, in supine and erect positions, at fixed and random times, on each of 3 consecutive days. The dependability (the proportion of true variance in total variance) of PtcO2 measurements was evaluated using a generalizability model. The preliminary generalizability study analysis indicated that day-to-day variation of PtcO2 level was larger than within-day variation. Therefore, in order to decrease the measurement error variance one would preferably increase the number of days for measurements (nd) rather than increase the number of measurements within each day (nt). A decision study analysis was also performed which resulted in estimates of error variance and two interdependent dependability measures: dependability coefficients (DCs) and signal to noise ratios (S/Ns). PtcO2 dependability values were generally different for the two groups. Cases had high DCs and S/Ns (DC greater than or equal to 0.9, S/N greater than or equal to 9) in all location-position combinations except for arm measurements. On the other hand, controls had low and unacceptable DCs and S/Ns (DC less than 0.8, S/N less than 4) in all location-position combinations. Cases and controls had generally lower dependability values when PtcO2 ratios were analyzed. The only two ratio-position categories for which dependability values were in the acceptable range (DC greater than or equal to 0.8, S/N greater than or equal to 4) were foot/arm erect and foot/arm supine for the cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Indications and role of axillofemoral bypass in high-risk patients

The purpose of this study was to determine whether axillofemoral bypass was justified as an alternative revascularization procedure to direct reconstruction and to specifically define the indications for this extraanatomical bypass. Forty-one patients operated on between 1978 and 1985 were evaluated. The average age was 69 years. Indications were based upon limb salvage for aortoiliac occlusive disease in the following situations: infected aortobifemoral bypass graft (8 patients) and high risk with co-existing medical problems (33 patients). Patients were classified according to Goldman's Multifactorial Index of Cardiac Risk and Cooperman's Cardiovascular Risk Index. Twenty-four patients had axillobifemoral bypass and 17 had unilateral axillofemoral procedures. In 66 femoral anastomoses there were 13 extended profundaplasties, 25 profunda arterioplasties, 11 profunda patch angioplasties and 16 anastomoses to the common femoral artery. Postoperative mortality was 4.8% (2 patients). Cumulative survival at 60 months was 43% +/- 11% and primary patency rate of the axillofemoral bypass was 69 +/- 9.8%. We conclude that axillo-femoral bypass is indicated in the presence of infection, in patients who fall into Goldman's Class III-IV or in patients with risk greater than 10% as calculated by Cooperman's equation.

Factors influencing results of femoropopliteal bypass operations for lower limb ischemia

An ideal way to assess the effectiveness of femoropopliteal bypass procedures is to standardize patient- and surgeon-related variables by randomization. Through statistical analysis of multiple factors influencing patency, limb loss, death rate and hospital stay, the authors reviewed retrospectively 136 bypass procedures performed over 5 years. Variables that contributed significantly to the results were: preoperative symptoms (p = 0.037), graft material used (p = 0.016), age of the patient (p = 0.007), adequacy of runoff (p = 0.041) and smoking postoperatively (p = 0.013). Autogenous vein grafts were superior to prosthetic grafts, the cumulative patency at 5 years being 67.5% and 38.2% respectively. The authors emphasize that all patients needing vascular surgery should be advised to stop smoking, since in this study postoperative smoking increased the probability of limb loss and adversely affected the cumulative patency rate by interaction with other variables such as preoperative symptoms, graft material and age.

Etiology and management of aorto-femoral bypass graft failure

Over a nine-year period 1973 to 1982, 364 aorto-bifemoral bypass grafts were inserted for aorto-iliac occlusive disease and 45 graft failures were encountered. Twelve patients developed acute graft occlusion, occurring less than 30 days postoperatively (Group I). These failures were almost all due to technical problems, the most common cause was elevation of an intimal flap following local endarterectomy. Five patients (Group II) developed recurrent symptoms without actual thrombosis or occlusion of the graft, but were associated with neointimal hyperplasia at the distal anastomosis and evidence of distal atherosclerosis. Twenty-eight patients were late failures (Group III). These patients thrombosed their grafts more than 30 days postoperatively. Four patients thrombosed both limbs of the graft at separate intervals. Nineteen patients were found to have progressive atherosclerosis affecting their run-off vessels. Six patients were found to have stenosis limited to the distal anastomosis. False aneurysm, kinking of the graft, and proximal suture line stenosis were felt to be determining factors in 3 other incidences of graft failure. The most common treatment in Group I was thrombectomy and securing of the raised intimal flap. The patients in Group II were treated with local endarterectomy and patch angioplasty. Of the patients in Group III, the most common inflow procedure was thrombectomy, carried out in 17 cases. In Group III, 13 of 28 patients underwent profundaplasty to improve outflow. The importance of pre and postoperative angiography in defining the etiology of graft failure is stressed. It is important to rule out problems with the proximal anastomosis. Once inflow has been established, angiography should ensure that an adequate outflow procedure has been performed.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of intravenous digital subtraction angiography as an adjunct to computed tomography in the preoperative assessment of patients with abdominal aortic aneurysm

The purpose of this article is to determine the role of intravenous digital subtraction angiography (IV-DSA) as an adjunct to computed tomography (CT) in the preoperative evaluation of patients with abdominal aortic aneurysm. Sixty-six patients underwent IV-DSA as well as CT during a 2-year period. Sixty-four of the 66 patients underwent abdominal aortic aneurysm repair. The results of the 66 patients were analyzed to assess what additional information was obtained by IV-DSA concerning aneurysm size, vascular anomalies, visceral arterial anatomy, associated aneurysmal disease, and iliofemoral and distal occlusive disease. On the basis of this study, it is suggested that IV-DSA has a limited role in the preoperative evaluation of patients with abdominal aortic aneurysm.

The effect of cigarette smoking on the long term success rates of aortofemoral and femoropopliteal reconstructions

Cigarette smoking is a recognized causative factor in the genesis of arterial insufficiency, but the precise effect of nonsmoking on the success of the operation is not well documented. Three hundred and twenty-six patients who underwent aortobifemoral bypass (209) or femoropopliteal bypass (117) between 1969 and 1978 were observed to determine whether or not the discontinuation of cigarette smoking affected the long term results of these grafts. Patients were divided into three groups: group 1 smoked preoperatively and postoperatively; group 2 smoked preoperatively but not postoperatively, and group 3 did not smoke at all. The five year cumulative success rates for aortobifemoral bypass in the groups were: 42 per cent for group 1 (130 patients); 77 per cent for group 2 (67 patients), and 71 per cent for group 3 (12 patients) (p less than 0.001). In the femoropopliteal group, the variation with regard to the known patency rates of autogenous and prosthetic grafts made the results more difficult to assess. For all grafts the five year cumulative success rates were: 38 per cent of group 1 (57 patients); 33 per cent for group 2 (40 patients), and 70 per cent for group 3 (20 patients) (p less than 0.001). Subdivision of groups 1 and 2 into autogenous and synthetic grafts gave identical success rates of 54 per cent for long saphenous vein grafts (66). Prosthetic grafts were successful at five years in 19 per cent of the patients in group 1 (16 patients) and 43 per cent in group 2 (15 patients). These results were not significant. These results clearly favor the postoperative nonsmoker over the smoker in the aortofemoral group but the distinction in the femoropopliteal group is less clear, although there is a similar trend.

Current indications for axillounifemoral and axillobifemoral bypass grafts

Revascularization of the lower extremities may require an axillofemoral bypass when an aortobifemoral bypass is contraindicated. Thirty-one patients underwent axillounifemoral and 59 had an axillobifemoral bypass, with a mortality rate of 9%. The indication for operation was limb salvage in 67%, intra-abdominal sepsis in 21%, and disabling claudication in 12%. Cumulative survival, patency, and limb salvage rates were determined by life-table analysis. The cumulative patency and limb salvage rates (with standard errors) at 3 years were 68% +/- 8% and 78% +/- 9%, respectively. When stratified for type of operation, axillobifemoral bypass had a superior patency rate compared with axillounifemoral bypass (log rank = 3.882, p less than 0.05). There was no significant difference when patients were stratified for diabetes (log rank = 2.213, p = no significance [NS]), operative indication (disabling claudication vs. limb salvage) (log rank = 0.0005, p = NS), or outflow (no profundaplasty vs. profundaplasty) (log rank = 2.011, p = NS). We conclude that axillofemoral bypass is a reasonable alternative for revascularization in high-risk patients or in those patients in whom a transabdominal approach is contraindicated. We recommend aggressive use of the profunda femoris artery when the superficial femoral artery is occluded to achieve optimal results.

Consequences of "conservative" conventional management of axillary vein thrombosis

To evaluate the long-term effects of "conservative" management (heparin initially then Coumadin for 3 months) on patients with axillary vein thrombosis, the authors studied 20 patients (average age 44 years) who presented at the Wellesley Hospital in Toronto between 1975 and 1984. The diagnosis of axillary vein thrombosis was made from history, findings on physical examination and Doppler studies. In 12 patients, the diagnosis was confirmed by venography. Three patients subsequently underwent a first-rib resection for thoracic outlet syndrome. The average follow-up was 42 months. The cause of the thrombosis in 3 patients was an intravenous-line catheter, in 7 it was effort thrombosis and in 10 the cause was unknown. Two patients had had a previous deep venous thrombosis in the lower limb. Results of conservative treatment showed that only five patients had residual minimal swelling and two had minor discomfort. These symptoms did not interfere with either leisure or work activities in any of the patients. Fifteen patients were asymptomatic. One patient had nonfatal pulmonary embolism. The conservative management of axillary vein thrombosis is safe, effective, relatively inexpensive and gives excellent long-term results. The prognosis is good, irrespective of the cause of the thrombosis and, in view of this, a more aggressive approach, using either streptokinase therapy or thrombectomy, does not appear to be justified.

Safety of cholecystectomy with abdominal aortic surgery

Many surgeons are reluctant to remove asymptomatic gallstones during aortic reconstruction for fear of increasing the risk of graft infection. This is a review of 56 patients who underwent aortofemoral bypass or aortic aneurysm repair, with cholecystectomy, to determine if the morbidity or mortality was increased with the concomitant procedure. Follow-up averaged 25 months (range from 1 to 125 months). Three patients were lost to follow-up. Operative and postoperative hospital stay were not increased. One patient suffered a graft infection and a pseudoaneurysm; the infection was not related to the cholecystectomy since it occurred after a secondary procedure for repair of an infected false aneurysm. There were three superficial infections and three postoperative deaths, none of which specifically related to the cholecystectomy. The only related complications were three bile leaks, one liver injury due to a retractor and bleeding from the gallbladder bed in one patient who required reoperation. The authors conclude that concomitant cholecystectomy can be performed without increased risk to the patient but is advised only if the vascular procedure has been uncomplicated and the cholecystectomy appears straightforward.

Hazards of epidural anesthesia in patients with previous vascular grafts

Two cases are described in which thrombosis of both limbs of an aortobifemoral bypass occurred after epidural anesthesia for a nonvascular operation. This has not previously been reported, and possible reasons for its occurrence are discussed. It seems likely that the hypotension associated with epidural anesthesia, particularly in patients already hypotensive or volume depleted, may precipitate this phenomenon. In addition, the sensory loss produced by the anesthetic may mask the signs and symptoms of acute vascular occlusion. Epidural anesthesia is not recommended in heparinized patients because of the risk of an epidural hematoma.

The predictability of the success of arterial reconstruction by means of transcutaneous oxygen tension measurements

The cases of 100 patients with severe peripheral vascular disease were reviewed to determine whether the success or feasibility of arterial reconstruction could be correlated with the increase in transcutaneous tissue oxygen tension (tcPO2) that occurs in all persons when assuming an erect posture from the supine position. Resting supine tcPO2 levels of 20 mm Hg or less at the foot were noted in all patients in this study (normal values 60.10 +/- 6.82 mm Hg). Group I patients were defined by an increase of less than 15 mm Hg on standing, whereas group II patients showed an increase of 15 mm Hg or more. Group I patients had a supine tcPO2 value of 4.24 +/- 5.31 mm Hg, with an increase of 3.91 +/- 4.59 mm Hg on standing. The group II subjects also had a low supine tcPO2 level, 5.73 +/- 4.98 mm Hg, but the increase on standing, 36.14 +/- 11.41 mm Hg, was significantly higher (p less than 0.001). When these levels increased by less than 15 mm Hg on standing in group I (31 patients), only 29% of limbs (10 of 34) were saved or had patent grafts at 3 months and 55% of attempted vascular reconstructions (11 of 20) failed. Amputations were performed in 50% of the limbs (17 of 34). This contrasted in group II (69 patients) with a significantly higher limb salvage and graft patency rate (81%, 57 of 70 limbs), success of reconstruction (79%, 37 of 47 procedures), and a significantly lower rate of amputation (11%, 8 of 70 limbs) (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Transcutaneous oxygen tension measurements in the detection of iliac and femoral arterial disease

The sensitivity and specificity of the noninvasive measurement of transcutaneous oxygen tension (PtcO2) in detecting the site of vascular disease in either the iliac or superficial femoral arteries is reported herein. Patients presenting with intermittent claudication or ischemic pain at rest were studied to determine the presence or absence of iliac or femoral occlusive disease by assessing the level of PtcO2 measurements at sites above and below the knee. PtcO2 studies were assessed against changes in the arteriogram, the "gold standard" for judging peripheral arterial insufficiency. Using our criteria, PtcO2 measurements above the knee show a sensitivity rate of 86 per cent and a specificity rate of 20 per cent to detect iliac disease. PtcO2 measurements below the knee show a sensitivity rate of 91 per cent and a specificity rate of 33 per cent to detect femoral disease. The accuracy was 69 per cent and 76 per cent, respectively. The user of the test is mainly concerned with the "predictive values" which are functions of the sensitivity, specificity and prevalence of the disease. Transcutaneous oxygen measurements above and below the knee show a very good sensitivity for detecting iliac and femoral disease, indicating that they may well serve as a quick and convenient noninvasive diagnostic procedure.

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.

Ascending aorta to bifemoral bypass--a ventral aorta

In the decade since April 1975 we accumulated a series of 18 patients with arterial conduits from the ascending aorta to the femoral arteries, 10 men aged 53 to 75 years (mean, 60 years) and eight women aged 33 to 56 years (mean, 50 years). In the first two patients, the conduit was placed subcutaneously; in the remaining 16 patients, it was placed behind the rectus muscle and in front of the posterior rectus fascia, thus following the ventral anastomotic axis of the internal mammary and inferior epigastric arteries. The conduit is not visible, palpable, or compressible in this position. This approach was usually chosen because of multiple failures of standard intra-abdominal and axillofemoral vascular reconstructions. Five patients had concurrent intramediastinal procedures, mostly coronary bypass or innominate artery repair. The early operations were performed with Dacron grafts with a bifurcation constructed just below the umbilicus. In the last nine patients, we have used an 8 or 10 mm polytetrafluoroethylene (PTFE) prosthesis and connected it to a 6 or 8 mm PTFE crossfemoral bypass. No operative deaths occurred. The 5-year patency rate by life-table analysis is 70%. This operation is an alternative to axillofemoral bypass in patients with an inoperable abdominal aortic aneurysm.

Organization of the department of surgery to facilitate undergraduate education

The chairman of the department of surgery is responsible for undergraduate education and should develop an organizational structure involving a director of undergraduate education for the every-day running of the undergraduate program and the determination of policies. This person should hold a relatively senior position and should have undergone specialist postgraduate training in educational methods and theory. The director should be supported by appropriate secretarial services and be compensated for this; the director should also sit on the faculty medical curriculum committee to close the circle of policy made at this committee with departmental policy. The departmental undergraduate education committee should include representatives from all hospitals involved in undergraduate education with representatives from the various systems. Some doubling up of representatives can occur. There should be a review process of both teaching methods and faculty teaching. The former will encourage change where appropriate and the latter award individuals for their contribution to the teaching process.

The use of transcutaneous oxygen tension measurements in the diagnosis of peripheral vascular insufficiency

Transcutaneous tissue oxygen tension (PtcO2) was evaluated as a noninvasive diagnostic test for peripheral arterial insufficiency; PtcO2 was measured at rest, during exercise, and following exercise at three leg sites in 36 controls and 138 patients with exercise-induced leg pain. Resting foot PtcO2 differed significantly in controls and in patients with rest pain (32/138) and was 60.1 +/- 6.82 mmHg and 3.66 +/- 3.68 mmHg, respectively (p less than 0.001). Abnormal resting PtcO2 values occurred in 80% of claudicants (85/138) and 20% had normal values. However, all vascular claudicants exhibited a decline in PtcO2 following exercise, a finding that distinguished them from controls (p less than 0.001). The PtcO2 values in 21 patients who were subsequently shown not to have vascular disease did not differ significantly from controls (p greater than 0.5). Comparison with angiograms (48) showed that PtcO2 following exercise had a 100% sensitivity and specificity in detecting the presence of arterial disease. If resting values alone are considered, sensitivity falls to 77%. This study demonstrates that measurement of PtcO2 at rest and particularly after exercise is a simple and sensitive noninvasive diagnostic test for peripheral arterial insufficiency. This test will serve to distinguish between vascular and other causes of exercise-induced leg pain.

The role of intraoperative heparin in reducing the incidence of postoperative deep venous thrombosis

A prospective study to determine the incidence of postoperative DVT in patients undergoing vascular surgical operations was carried out. Twenty-eight patients who underwent vascular surgical procedures were studied. Five thousand units of intravenously given heparin was administered intraoperatively to each patient, with no other prophylaxis against DVT being used. DVT was detected by means of radioactive fibrinogen uptake studies. Two patients had DVT develop, an incidence of 7.1 per cent which is lower than the 30 to 40 per cent that might be expected in patients of the same age undergoing general surgical procedures. Both DVT developed in the late postoperative period. It is suggested that the single dosage of heparin given to these patients protects them against the development of DVT and is responsible for the low incidence of DVT observed in these patients.

Infected arterial grafts: clinical manifestations and surgical management

The clinical manifestations and results of management in twenty-five patients treated for infected vascular grafts are reviewed. The overall incidence of infection in this series of prosthetic grafts is 1.4%. Staphylococcus aureus was found to be the single most common infecting organism and multiple organisms were found in nine patients. Therapy was divided into three methods of management: local therapy alone resulted in a mortality of 45% and an amputation rate of 36.3%; partial graft excision resulted in a mortality of 20% and an amputation rate of 60%; total graft excision resulted in a mortality of 22% and an amputation rate of 22% as well. All amputations were above-knee amputations and the most common cause of death was continuing sepsis. The overall mortality of 32% and a loss of limb rate of 44% are testimony to the serious nature of this problem.

Intraoperative single-dose heparin prophylaxis against deep-vein thrombosis

This randomized prospective study examines the efficacy of intravenously administered heparin as prophylaxis against deep-vein thrombosis, detected isotopically with iodine 125, in 37 patients scheduled to undergo major abdominal procedures. Twenty patients were given 5000 units of sodium heparin on opening the abdominal cavity, while 17 patients who did not receive heparin acted as controls. The effect of heparin was reversed at the end of the operative procedure by protamine. Three control patients had deep-vein thrombosis postoperatively but only one heparin-treated patient did. Complications in the treated group included excessive blood loss intraoperatively in one patient and an incisional hernia postoperatively in another. Although the results are not statistically significant, this study suggests that a single dose of heparin given intravenously during operation is a safe and effective means of prophylaxis against deep-vein thrombosis in patients who undergo general surgical procedures. Studies are now being carried out to determine the optimal dose of heparin, time of administration and duration of anticoagulation.

Radiation damage to large arteries

Little is known about late changes in large arteries after radiotherapy. Much more is known about damage to other organs and tissues. The arterial changes resemble chronic, progressive atherosclerosis which may be due to a combination of periarterial fibrosis, direct damage to the arterial wall, occlusion of vasa vasorum and acceleration of naturally occurring atherosclerosis. Factors that may predispose to arterial occlusion that relate to radiotherapy include maximum tissue dose, beam energy and field size. The authors present four patients with axillary artery occlusion that occurred 10 to 27 years after mastectomy and irradiation. The axillary artery is seldom affected by segmental atherosclerotic occlusive disease. Hence, the cause of the occlusion was most likely the irradiation. All patients did well after bypass grafting.

Unusual aneurysms of the extracranial carotid artery

Aneurysms of the extracranial internal carotid artery are rare and only 4 cases have been treated at the Wellesley Hospital since 1969. These aneurysms usually present as a painless lump in the neck and the 4 cases to be described manifest unusual presentations. One patient with a history of facial sepsis presented in the Emergency Department with what was thought to be a neck abscess. This was incised and drained before the true nature of the swelling was appreciated. Two patients presented with nerve palsies, one with a hypoglossal palsy due to stretching of the hypoglossal nerve over a large aneurysm and the second with recurrent laryngeal nerve palsy as a result of rupture of a false aneurysm from disruption of a saphenous vein patch inserted following carotid endarterectomy 9 months earlier. The fourth patient presented with a carotid bruit and had a stenosis distal to the aneurysm. Although rare, carotid aneurysms require recognition and early treatment if neurological sequelae are to be avoided.

Femoropopliteal bypass: saphenous vein and expanded polytetrafluoroethylene grafts

The patency of 181 saphenous vein and expanded polytetrafluoroethylene (PTFE) femoropopliteal bypass grafts was assessed during a follow-up that ranged from 1 to 53 months after operation. Significantly better patency (P less than 0.05) was noted with saphenous vein (70%) than with PTFE (56%). Life-table analysis at 30 months demonstrated a cumulative patency of 50% for saphenous vein grafts versus 39% for PTFE, while at 53 months the rates were 46% and 33% respectively. The PTFE grafts tended to occlude earlier than saphenous vein grafts but after the initial year, both types of graft failed at a rate of about 5% a year. Patency was similar in both groups when operation was performed for claudication, but for limb salvage operations saphenous vein patency was superior to PTFE. Although the groups were similar in constitution, a higher percentage of patients in the PTFE group had undergone previous vascular operations.

Investigation of impotence by internal pudendal angiography: experience with 73 cases

Angiography of the ileopudendal vascular tree was performed for the evaluation of impotence in 73 patients. This technique proved useful in identifying those cases caused by vascular lesions in major arteries and small penile vessels. Organic diseases cause a much higher proportion of impotence than in generally suspected, with vascular occlusions causing the greatest number of cases. Nocturnal penile tumescence (NPT) studies are the best screening procedure in the author's view. In this series, NPT was followed by angiography, which provided the definitive diagnosis.

Fate of the limb after failed femoropopliteal reconstruction

Sixty-eight occluded femoropopliteal bypass grafts were studied to determine the fate of the limb after graft occlusion. There were 25 reversed saphenous vein grafts and 43 polytetrafluoroethylene grafts. Thirty-five limbs required amputation and the timing of amputation after graft thrombosis ranged from 1 day to 24 months. Twenty of the amputations occurred following an unsuccessful revision of the thrombosed graft and an additional 15 limbs were amputated without further attempts at revascularization. In 17 of the patients there were no disabling signs or symptoms after graft occlusion. Twenty-two grafts were successfully revised to avoid amputation. The need for amputation and the level of amputation were analysed with respect to the age of the patient, the indication for the original procedure, inflow and outflow status, the type of graft and the level of distal anastomosis. In 26 patients with intermittent claudication only four amputations resulted from graft occlusion and these were all below the knee. There was a weakly significant (P less than 0.1) correlation between poor outflow and the need for amputation after occlusion of the graft. In particular, patients with femorodistal bypass faired poorly, four of five occluded saphenous vein grafts and all six PTFE grafts requiring amputation. There was no significant age difference with respect to the level of amputation or the need for amputation and there was a wide range from the time of thrombosis to amputation. The authors conclude that amputations are infrequent after bypass grafting for claudication. The level of distal anastomosis, poor inflow and run-off and gangrene before the bypass procedure all correlate with the need for amputation in thrombosed grafts initially placed for limb salvage. Vigorous attempts at revision of failed grafts may prevent or constructively delay amputation.

Percutaneous transluminal angioplasty in peripheral vascular disease: a review

Percutaneous transluminal angioplasty is a relatively new technique employed in the treatment of stenoses or occlusions of peripheral arteries. While the longterm success rates have yet to be determined, short-term results have been excellent. The procedure has greatest value in the dilatation of localized lesions, avoiding surgery and its attendant risks. However, PTA and surgery are complementary, not competing, modes of therapy. PTA complements the traditional therapy of peripheral vascular disease, which remains reconstructive surgery.