Diagnosis and management of failing lower extremity arterial reconstructions prior to graft occlusion.

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.

System for widespread application of microcomputers to vascular surgery.

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.

Quantitative assessment of outflow resistance in lower extremity arterial reconstructions.

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)