Faculty Bibliography

Routine arteriography of the axillary, subclavian, and innominate arteries before axillofemoral bypass surgery has not been advocated because of the presumed rarity of stenosis of these inflow vessels. However, we have noted in this patient population with extensive atherosclerosis that inflow disease can cause axillofemoral graft failure despite normal preoperative clinical and noninvasive parameters. We prospectively determined the incidence of unsuspected inflow stenosis with arteriography in 40 consecutive candidates for primary (28) or secondary (12) axillofemoral bypass surgery. A new arteriographic technique with a single translumbar puncture was developed to safely and clearly visualize the potential inflow and outflow tracts. Ten of the 40 patients (25%) exhibited inflow stenosis greater than 50% of luminal diameter (unilateral in eight patients and bilateral in two patients). Seven were on the left side (five subclavian, two axillary) and five were on the right side (three subclavian, one axillary, one innominate). In eight of the 40 patients (20%) the stenotic inflow lesion was ipsilateral to the ischemic leg and therefore proximal to the preferred inflow site of an axillofemoral bypass. Upper extremity arterial pressure measurements suggested potential inflow artery stenosis in only three of the 12 (25%) instances. These findings show that equal arterial pressures in the upper extremities do not ensure adequate inflow for an axillofemoral graft. Routine arteriographic assessment of inflow intacts is recommended before axillofemoral bypass surgery

Detection of failing arterial reconstructions requires intensive surveillance by frequent physical examination and noninvasive laboratory testing. However, many grafts fail during the intervals between these examinations. For this reason, we have developed an implantable miniaturized piezoelectric flow detection device whose function can be monitored externally by radiotransmission across the skin. Sensors were constructed from ultrathin polyvinylidene fluoride (PVF2) with piezoelectric activity and attached with silicone fixative to 6-mm polytetrafluoroethylene grafts. Ten of these grafts were placed in mongrel dogs as iliofemoral bypasses. Real time data were acquired from the sensors at a rate of 200 Hz, using a DATAQ A/D data acquisition board and CODAS data acquisition software, while simultaneous blood flow (using an electromagnetic flowmeter) and intraluminal pressure were processed by using separate channels of the same data acquisition board. The data were stored on computer storage media and analyzed by the ASYST software, which allows simultaneous signal curves to be compared using regression analysis. In the resting state, the mean blood flow was 123 +/- 16 mL and the mean intraluminal pressure was 124/78 mm Hg, and there was perfect correlation between the PVF2 sensor and the flowmeter and between the sensor and the intraluminal pressure (correlation coefficient, r greater than or equal to 0.99 and r greater than or equal to 0.93, respectively). A tourniquet was applied to the iliac artery proximal to the graft to reduce the flow to approximately half of the resting state (mean flow after tourniquet: 66 +/- 6 mL/minute). Signal tracings from the three sources showed a remarkable similarity with a very high correlation coefficient (r greater than or equal to 0.99 between sensor and flowmeter and r greater than or equal to 0.92 between sensor and the pressure signal). These preliminary results show that the sensors made from low-profile and low-mass PVF2 material have the potential of being implanted around grafts for long-term, continuous monitoring of graft function. Further studies involving long-term implantation to assess the effect of tissue ingrowth and loss of compliance are necessary before this device can be used clinically

With multilevel arteriosclerosis, some patients undergoing infrainguinal bypass grafting will develop femoral/brachial pressure gradients only after the bypass is performed. We therefore evaluated arteriographically alternate inflow sites and measured the femoral/brachial pressure gradients before and after placement of 87 femorofemoral and 510 femoropopliteal/infrapopliteal bypasses. No prebypass femoral/brachial pressure gradients were present with and without intraarterial papaverine. However, femoral/branchial pressure gradients greater than or equal to 15 mm Hg were observed after the bypass placement in 16 femorofemoral patients and 43 femoropopliteal/infrapopliteal patients. Gradients averaged 28 +/- 8 (SD) (range, 15 to 50) mm Hg. The post femorofemoral bypass gradients were treated by immediate supplementary inflow extension to the aorta (three patients) or an axillary artery (three patients); by postoperative iliac percutaneous transluminal angioplasty (four patients) or by no treatment (six patients with femoral/brachial pressure gradients of 15 to 35 [23 +/- 5] mm Hg). The 43 postfemoropopliteal/infrapopliteal bypass gradients were treated by immediate supplementary inflow extension to the contralateral femoral artery (15 patients), the aorta (8 patients), or an axillary artery (3 patients); by postoperative iliac percutaneous transluminal angioplasty (5 patients) or by no treatment (12 patients with femoral/brachial pressure gradients of 15 to 30 [21 +/- 4] mm Hg). No thrombosis occurred in the 10 femorofemoral bypasses with postbypass femoral/brachial pressure gradients that were treated. One of the six femorofemoral patients with untreated gradients required a subsequent aortic extension, and one thrombosed after 2 years. Of the 12 untreated patients with femoropopliteal/infrapopliteal bypasses one graft occluded early, and two late failures occurred 12 and 18 months later.(ABSTRACT TRUNCATED AT 250 WORDS)

Secondary interventions play an important role in achieving the ultimate goal of limb salvage after primary infrainguinal interventions fail. By employing the described strategies and principles for secondary arterial reconstructions below the inguinal ligament, good results in terms of patency of the reoperated primary reconstruction or the secondary reconstruction can be obtained with significantly augmented limb salvage at a low cost in operative morbidity and mortality. These results mandate that vascular surgeons maintain an aggressive attitude toward the use of these secondary operations when a primary procedure fails to achieve or maintain its intended goal and a patient is faced with imminent limb loss because of distal ischemia

Ventricular ejection fraction is widely regarded as a prognostic indicator of perioperative myocardial infarction. To evaluate this premise the prevalence of perioperative myocardial infarction or cardiac death was analyzed in relation to preoperative resting gated pool ejection fraction in 85 patients undergoing vascular surgery for infrainguinal bypass grafting. Patients were divided into three groups on the basis of ejection fraction. Group I consisted of 50 patients with ejection fractions of 56% to 92%. Nine (18%) perioperative myocardial infarctions occurred in group I, and there were no cardiac deaths. Group II consisted of 20 patients with ejection fractions of 37% to 55%. Three (15%) myocardial infarctions occurred in this group, and there were no cardiac deaths. Group III included 15 patients with ejection fractions of 20% to 35%. Three (20%) cardiac events occurred in group III including one nonfatal myocardial infarction and two (13%) cardiac deaths. Statistical analysis showed no significant difference in prevalence of cardiac events between any group. These results suggest that resting ejection fraction is a poor predictor of perioperative myocardial infarction in patients undergoing vascular surgery. Patients with normal ejection fractions, but underlying coronary artery disease, are still at significant risk for a perioperative cardiac event