Faculty Bibliography

We have used a simple reproducible method to measure total outflow resistance (OR) and its proximal and distal components in 101 bypasses (46 femoropopliteal [FP] and 55 femorodistal [FD]). All bypasses with a distal OR greater than 1.2 mm Hg/ml/min failed within 3 months and all with distal OR less than 1.2 mm Hg/ml/min remained patent for at least 3 months. To evaluate the contribution of vasospasm to OR and its role in graft failure, 60 bypasses (29 FP, 31 FD) had OR measurements before and after local infusion of papaverine hydrochloride (60 mg). Within 3 months, nine grafts (all FD) occluded and 51 remained patent. All nine failures had distal OR greater than 1.2 mm Hg/ml/min before papaverine infusion. After infusion, the mean percentage decrease in both total and distal OR for all grafts was 30% and 31%, respectively. However, there was no significant difference between these papaverine-induced decreases in OR and 3-month graft failure or success. Moreover, in three bypasses, even though papaverine lowered the distal OR from greater than 1.2 to less than 1.2 mm Hg/ml/min, early occlusion occurred. In six grafts (1 FP, 5 FD) when total and distal OR before and after papaverine was greater than 1.2 mm Hg/ml/min, the graft was extended to a second distal artery as a sequential bypass. These six grafts have remained patent over 3 months. Thus measurement of OR and particularly distal OR is a most accurate predictor of early graft success or failure. Pharmacologic manipulation does not enhance the predictive value of the OR measurement. OR measurements also help to select those FD bypass cases in which extension to a second distal artery as a sequential bypass improves patency

In 191 instances, infrainguinal graft occlusion was presumed because of a rethreatened foot, diminished pulses and/or decreased ankle pressure. Routine urgent arteriography revealed 38 instances where the graft was patent (22 vein, 16 PTFE). Ten of these grafts were to the femoral artery, 18 to the popliteal artery and 10 were to infrapopliteal arteries. The deterioration despite a patent graft was due to development of inflow stenosis (15), vein graft lesions (13) or distal disease progression (10). All were treated successfully by percutaneous transluminal angioplasty (30) or simple local operative revisions (8). Cumulative life table patency rates 2 years after reintervention were 89% for failing reconstructions to the femoral artery, 94% for those to the popliteal artery and 89% for infrapopliteal procedures. Comparable rates for limb salvage were 90%, 100% and 100%, respectively. These findings underscore the importance of urgent angiography in suspected lower extremity graft failure. Defects may be detected before real graft occlusion occurs and appropriate interventional treatment can provide important additional periods of limb salvage

The application of microcomputers to vascular surgery has been limited because of the lack of software that allows collection and effective evaluation of a large amount of patient-related data. We have developed a microcomputer-based data handling system for evaluating vascular patients that is inexpensive ($6000 to $8000), easy to use, and flexible. Its simplicity for nonprogrammers is achieved through a natural interface with menu-driven operations and descriptive English language messages. With this system eight data entry forms were designed, and data on more than 1000 patients treated for peripheral vascular disease over the last 7 years were entered into the computer by clerical personnel with minimal training. A query language report generator allowed us to obtain reports of results in simple English on any set of selection criteria with all relevant statistical functions, including cumulative life-table patency rates. This system has the following advantages: rapid evaluation of data from several retrospective and prospective studies, such as comparison of graft material, effect of local and systemic risk factors, cost of limb-salvage surgery, and correlation of noninvasive laboratory tests with other parameters; more accurate patient follow-up, with elimination of many of the pitfalls involved in observing large groups of patients frequently; and quantitation of individual surgeon or service results for quality control and self-review, which guide the vascular surgeon to modify treatment protocols, patient selection, and/or surgical techniques. Wider use of this system for data collection and evaluation will help to standardize data reporting and thus allow accurate comparison of data from different centers

Graft patency is thought to correlate with resistance in the runoff bed or outflow resistance. However, accurate measurement of this parameter has been difficult. A simple and reproducible method for direct measurement of outflow resistance following completion of the distal anastomosis of a bypass graft has been developed. This method employs injection of a fixed amount of normal saline through the proximal end of the graft and measurement of the resulting integrated pressure increment by an analog computer. Division of this pressure integral by the volume injected is a measure of the outflow resistance expressed in resistance units (mm Hg/ml/min). The median outflow resistance in 31 femoropopliteal bypasses was 0.29 units with a range of 0.08-1.38 units. The median outflow resistance in 33 femorodistal bypasses was 0.7 units with a range of 0.18-2.34 units. All bypasses with an outflow resistance of 1.1 units or less remained patent for 3 months. There were 51 grafts in this group (30 femoropopliteal; 21 femorodistal) and their outflow resistance ranged from 0.08 to 1.1 units. All bypasses with an outflow resistance of 1.2 units or higher thrombosed within the first postoperative month. There were 13 grafts in this group (1 femoropopliteal; 12 femorodistal) and their outflow resistance ranged from 1.2 to 2.38 units. Eight of the 13 grafts that failed originally were subjected to thrombectomy, which was uniformly unsuccessful. Although this method does not yet allow bypass surgery to be denied to any patient, it does define a group of patients in whom thrombectomy will not be effective and should not be attempted.(ABSTRACT TRUNCATED AT 250 WORDS)

Subclavian artery compression by a cervical rib is an uncommon but potentially disabling condition. A series of 12 patients with 15 arterial lesions is reviewed and a staging system proposed to provide guidelines for managing patients with this condition. Stage I lesions have only arterial stenosis and minor poststenotic dilatation and are managed by thoracic outlet decompression, usually consisting of cervical rib resection. Stage II lesions have intrinsic arterial damage usually with subclavian aneurysm formation and require rib resection, aneurysmectomy, and arterial reconstruction. Stage III lesions present with distal thromboembolic complications and require thrombectomy or embolectomy in addition to thoracic outlet decompression and arterial reconstruction. The anatomic and pathophysiologic bases of the syndrome are reviewed and clinical and angiographic examples of each stage are presented

To determine femoropopliteal graft patency, the ankle-brachial pulse index and the ankle pulse volume recording amplitude were measured. Fourteen healthy volunteer subjects were tested on two occasions over 24 hours (ankle-brachial pressure index 1.14+:-0.16, change 0.03+:-0.05; ankle pulse volume recording amplitude 25+:-7 mm, change 5+:-4 mm). In the second control group, hemodynamic function in the unoperated limb was studied before and after surgery in 40 patients undergoing infrainguinal bypass on the contralateral side (preoperative ankle-brachial pressure index 0.66+:-0.3, change 0.02+:-0.12; preoperative ankle pulse volume recording amplitude 8+:-7 mm, change 1+:-3 mm). After 119 patent femoropopliteal bypasses ankle-brachial pressure index and ankle pulse volume recording amplitude increased by 0.41+:-0.26 and 11+:8 mm, respectively

In order to assess the effect of revascularization on the healing of bronchial anastomoses in a canine model, we developed a microsurgical technique that permits the immediate reperfusion of the distal bronchial segment by a direct anastomosis of the bronchial artery to an intercostal artery. This technique was applied to dogs that underwent hilar stripping and bronchial transection and reanastomosis, and it prevented the development of ischemic bronchial damage. In addition, several groups of dogs that had undergone bronchial transection and reanastomosis and, in some cases, reestablishment of bronchial arterial circulation, were treated with 40 mg of prednisone daily for periods of 7 and 21 days. The animals treated with corticosteroids demonstrated a lesser degree of inflammatory damage to the bronchial anastomotic site than similar groups of untreated animals. These findings support the hypothesis that restoration of bronchial arterial blood flow at the time of lung transplantation can reduce anastomotic damage to the distal or donor bronchial component. Our results further suggest that corticosteroid therapy alone does not increase bronchial anastomotic damage, and, in fact, may reduce inflammation at the bronchial anastomotic site