Faculty Bibliography

Acute venous disorders include deep venous thrombosis, superficial venous thrombophlebitis, and venous trauma. Deep venous thrombosis (DVT) most often arises from the convergence of multiple genetic and acquired risk factors, with a variable estimated incidence of 56 to 160 cases per 100,000 population per year. Acute thrombosis is followed by an inflammatory response in the thrombus and vein wall leading to thrombus amplification, organization, and recanalization. Clinically, there is an exponential decrease in thrombus load over the first 6 months, with most recanalization occurring over the first 6 weeks after thrombosis. Pulmonary embolism (PE) and the post-thrombotic syndrome (PTS) are the most important acute and chronic complications of DVT. Despite the effectiveness of thromboembolism prophylaxis, appropriate measures are utilized in as few as one-third of at-risk patients. Once established, the treatment of venous thromboembolism (VTE) has been defined by randomized clinical trials, with appropriate anticoagulation constituting the mainstay of management. Despite its effectiveness in preventing recurrent VTE, anticoagulation alone imperfectly protects against PTS. Although randomized trials are currently lacking, at least some data suggests that catheter-directed thrombolysis or combined pharmaco-mechanical thrombectomy can reduce post-thrombotic symptoms and improve quality of life after acute ileofemoral DVT. Inferior vena caval filters continue to have a role among patients with contra-indications to, complications of, or failure of anticoagulation. However, an expanded role for retrievable filters for relative indications has yet to be clearly established. The incidence of superficial venous thrombophlebitis is likely under-reported, but it occurs in approximately 125,000 patients per year in the United States. Although the appropriate treatment remains controversial, recent investigations suggest that anticoagulation may be more effective than ligation in preventing DVT and PE. Venous injuries are similarly under-reported and the true incidence is unknown. Current recommendations include repair of injuries to the major proximal veins. If repair not safe or possible, ligation should be performed.

In an effort to explore alternatives to contrast arteriography, we compared computed tomography angiography to contrast arteriography for defining anatomic features of patients undergoing lower extremity revascularization. From November 2003 to March 2004, 36 inpatients with chronic lower extremity ischemia underwent contrast arteriography and computed tomography angiography before undergoing lower extremity revascularization procedures. A Siemens 16 slice multiplanar computed tomography device with bolus tracking was used for these exams. The reports of these tests and images were compared prospectively, and the differences in the aorto-iliac segment, femoral-popliteal, and infrapopliteal segments were noted. The vessels were classified as mild disease (<50%), moderate disease (50%-70%), severe (71%-99%), and occluded. The studies and treatment plans based on these data were compared. The mean age was 76 +/- 12 years (SD). Indications for the procedures included gangrene (45%), ischemic ulcer (32%), rest pain (19%), and severe claudication (3%); 69% were diabetics. Accuracy of computed tomography angiography in the aorto-iliac, femoral-popliteal, and infrapopliteal segments was 100%, 81%, and 59%, respectively. Thirteen of 18 (72%) of these disagreements resulted in a different procedure than that suggested by computed tomography angiography. A review of the data obtained in this series indicated that computed tomography angiography appears to be unable to obtain adequate information in this highly selected population at our institution.

Duplex arteriography may be a potential replacement of preoperative standard contrast arteriography for peripheral arterial imaging in lower extremity revascularization procedures. In patients with chronic or acute ischemia, a well-performed duplex arteriography offers several practical advantages over contrast arteriography: it is noninvasive; it does not require nephrotoxic agents; it is portable and can be done expeditiously; color flow and waveform analysis provide a better estimation of the hemodynamic significance of occlusive disease; it allows direct visualization of the entire artery and not only of the lumen thus enabling plaque characterization; with color flow and power Doppler techniques, it is possible to identify patent arteries subjected to very low flow states; and it can detect occluded arterial aneurysms thereby avoiding unnecessary attempts at thromboembolectomies. High-quality arterial ultrasonography performed by a highly skilled and well-trained vascular technologist may represent an alternative to conventional arteriography for patients in need of primary or secondary lower extremity revascularization.

The conventional balloon angioplasty of infrainguinal arteries requires the use of fluoroscopy and injection of contrast material. We attempted to perform 360 balloon angioplasties of the superficial femoral (SFA) and/or popliteal arteries under duplex guidance in 274 patients to avoid the nephrotoxic effect of contrast and eliminate or minimize radiation exposure. Critical ischemia was the indication in 35% of cases and severe claudication in 65%. Infrapopliteal angioplasties of 80 arteries were attempted in 54 cases (15% of all cases) in order to improve the run-off after completion of femoral-popliteal angioplasties. For femoral-popliteal segment, overall technical success was 95% (342/360 cases). For infrapopliteal arteries, technical success was achieved in 77 of 80 cases, with an overall success rate of 96%. Twelve-month patency rates for TASC class A, B, C, and D lesions were 90%, 59%, 52%, and 46%, respectively. PAVF <100 mL/min was the most powerful predictor of 30-day and 6-month arterial thrombosis following femoral/popliteal balloon angioplasties.Duplex-guided balloon angioplasty and stent placement appears to be a safe and effective technique for the treatment of femoral-popliteal and infrapopliteal arterial occlusive disease. PAVF <100 mL/min is the most powerful predictor of early (30 days) and midterm (6-month) arterial thrombosis following femoral-popliteal interventions.

Endovascular repair of failing infrainguinal bypasses can effectively improve patency and limb salvage results in selected cases. We attempted to perform balloon angioplasties of 47 failing grafts in 3 patients under duplex guidance to eliminate or diminish the use of nephrotoxic contrast material and radiation exposure. The technical success was 98% (46/47 cases). One case of the outflow lesion in the plantar artery could not be traversed with the guidewire due to extreme tortuosity. Overall local complications rate was 4% (2 cases). One vein bypass pseudoaneurysm caused by rupture with cutting balloon was repaired by patch angioplasty and 1 SFA pseudoaneurysm at the puncture site required open repair. Overall 6- and 12-month primary patency rates were 70% and 50%, respectively.Duplex guidance of failing infrainguinal arterial bypasses appears to be an effective treatment modality. Advantages include visualization of the puncture site, accurate selection of the proper size balloon, and confirmation of the adequacy of the technique by hemodynamic and imaging parameters. Additional benefits are avoidance of radiation exposure and contrast material in most cases.

Carotid artery balloon angioplasty and stenting (CBAS) is gaining popularity as an adequate alternative to carotid endarterectomy (CEA) in selected patients. Unfortunately, the substantial amount of contrast media used for CBAS, traditionally performed under fluoroscopic guidance, may impair renal function in patients with diabetes or ones with elevated serum creatinine. We attempted to apply duplex assistance to limit or eliminate the use of contrast during CBAS. Fluoroscopy was utilized to assist manipulation of the guidewire into the aorta and the common carotid artery, and positioning of the distal cerebral protection device. Selective catheterization of the internal and external carotid arteries was performed under ultrasound guidance. Balloons and stent were successfully deployed with ultrasound guidance alone in all cases. Appropriate stent apposition and arterial patency were confirmed by duplex in all cases. One ipsilateral stroke (2.9%) occurred intraoperatively with almost complete clinical recovery in 4 months. On-table biplanar cerebral arteriogram performed in this patient was normal. No early (30-day) mortalities were in the series. Duplex-assisted CBAS is feasible and may reduce the need for contrast media in selected patients with high risk for renal failure. Additional advantages include guidance of the femoral puncture, precise position of the balloon and stent and B-mode and hemodynamic confirmation of the adequacy of the technique.

In vascular surgery, the gold standard for evaluation of the lower-extremity arterial tree has long been contrast arteriography (CA). Associated risks of CA are well-documented and include severe allergic reactions, arterial injury and/or hemorrhage, and contrast-induced nephropathy. Increasingly, less-invasive techniques, with fewer inherent risks for complication, are being explored as diagnostic alternatives. Magnetic resonance angiography, computed tomography angiography, and duplex arteriography, each offer distinct advantages, though are not without limitation. This review explores the indications, advantages, and disadvantages of these newer technologies and provides a comparison to CA as a means for defining the anatomic features of patients undergoing lower-extremity revascularization. This data suggests that noninvasive imaging technologies may, in the future, play an increasingly important role in the surgical evaluation of the patient with lower-extremity ischemia.

Diagnostic arteriography and balloon angioplasty of failing or nonmaturing arterio-venous (AV) access is based upon using nephrotoxic contrast. Patients not yet on dialysis with borderline renal function with nonmaturing AV accesses or ones with an allergy to contrast media present a therapeutic challenge. We have used duplex scanning as an alternative imaging modality to guide endovascular therapy in 10 cases (9 autologous and 1 prosthetic). Six target AV accesses (60%) were used for dialysis. Number of stenoses ranged from 1 to 5 per AV access. Short access sheath insertion, wire and balloon passage, and inflation were guided by duplex only. Balloon size (5-8 mm in diameter) was chosen based on duplex measurements. Cutting balloons (4 x 20 mm and 5 x 20 mm) were used for dilatation of recoiling lesions in 4 cases. One patient had a self-expanding stent placed under duplex-guidance for recoiling lesion in the junction of the brachial and axillary veins. Angioplasty of failing AV access can be performed under duplex guidance alone. Duplex guidance offers very important advantages of hemodynamic evaluation for recoiling lesions and need for stenting. Avoidance of contrast use for repair of nonfunctioning AV access can be a useful option in patients with renal failure not yet on dialysis or in cases of allergy.

OBJECTIVE: We have investigated whether popliteal artery volume flow (PAVF) measured immediately after balloon angioplasties of the superficial femoral artery-popliteal segments (SFA/POP) was predictive of early (30 days) and mid-term (6 months) arterial thrombosis. METHODS: During the last 24 months, 203 patients (56% men) with a mean age of 73 +/- 9 years had 268 duplex-guided balloon angioplasties of the SFA/POP. Critical ischemia was the indication in 36%. Group I included 176 (66%) with stenoses, and group II had 92 (34%) with occlusions. All patients had completion duplex examinations that included three measurements of PAVF of below-the-knee popliteal artery. RESULTS: Early (30 days) thrombosis of the treated femoropopliteal arterial segment developed in 10 patients (3.7%), three in group I (1.7%) and seven in group II (7.6%; P < .04). All 10 cases of early thrombosis were in patients with TransAtlantic Inter-Society Consensus (TASC) class C (6/185, 3.2%) and D (4/26, 15%) lesions. Moreover, the 19% incidence (n = 4) of early thrombosis in patients with PAVF <100 mL/min (mean, 73 +/- 24 mL/min; range, 20 to 99 mL/min) was higher compared with the 2.4% rate for patients with higher flows (mean, 176 +/- 60 mL/min; range, 100 to 450 mL/min; P < .01). At 6 months of follow-up, femoropopliteal occlusions had developed in nine more patients, and it became apparent that low PAVF measurements were still predictive of thrombosis (29%) when compared with higher PAVF cases (6%; P < .002). Log-rank comparison of survival curves for cumulative primary stenosis-free patency in group I and group II demonstrated a statistically significant difference (P < .02). PAVF <100 mL/min and TASC classification were significant predictors of early (30 days) and mid-term (6 months) arterial thrombosis after femoropopliteal angioplasties. PAVF was the most powerful predictor of arterial thrombosis. The respective 6-month and 12-month limb salvage rates were 98% and 94% for patients with claudication and 88% and 85% for those with limb-threatening ischemia (P < .0001). CONCLUSIONS: Our results demonstrate that low PAVF is the most powerful predictor of early (30 days) and mid-term (6 months) arterial thrombosis after femoropopliteal interventions. In the presence of a low postprocedure PAVF (<100 mL/min), one may consider not reversing the heparin or using intermittent calf compression, or both, to augment the arterial flow.