Faculty Bibliography

OBJECTIVE: Due to the inherent risks, deficiencies and cost associated with contrast arteriography (CA), our group has been utitilizing duplex arteriography (DA) for evaluating the arteries of the lower extremity for patients undergoing lower extremity revascularization. In an effort to further explore the strengths and weaknesses of DA, we reviewed our evolving experience with DA from January 1, 1998, to January 1, 2005. PATIENTS AND METHODS: The arterial segments starting from mid-abdominal aorta to the pedal arteries were studied in cross-sectional and longitudinal planes using a variety of scanheads of 7-4, 10-5, 12-5, 5-2 and 3-2 MHz extended operative frequency range to obtain high-quality B-mode, color and power Doppler images as well as velocity spectra. In 906 patients, 1,020 duplex arteriograms were obtained. The ages ranged from 30-98 years old with a mean of 73+/-11 (SD) years. Fifty percent of the patients were diabetics. Indications for the examination included: tissue loss (409), rest pain (221), claudication (310), acute ischemia (74), popliteal aneurysm (45), SFA aneurysm (2), abdominal aortic aneurysms (AAA) (10) and failing bypass (55). Prior procedures had been performed in 262. DA was performed by six technologists (4 of whom are MDs). In all, 207 DA were performed intraoperatively and the remainder, preoperatively. RESULTS: The resultant procedures based upon DA included: bypass to the popliteal artery (262) and bypass to an infrapopliteal artery (325), endovascular procedures (363), thrombectomy (11), embolectomy (9), inflow bypass procedures to the femoral arteries (46), debridment (4), amputation (8) and no intervention (75). The areas not visualized well included: iliac (73), femoral (26), popliteal (17), and infrapopliteal (221). Additional imaging after DA was deemed necessary in 102 cases to obtain enough information to plan lower extremity revascularization. Factors associated with increased need to obtain CA included: DM (p<.001), infrapopliteal calcification (p<.001), older age (p = .01) and limb threatening ischemia (p<.001). Factors not associated with the need to obtain CA included: which technologist performed the exam, whether the technologist has a medical degree and whether the patient underwent prior revascularization. CONCLUSIONS: In 90% of patients reviewed, DA is able to obtain the needed information to plan lower extremity revascularization. Severe tibial vessel calcification is the most common cause of an incomplete DA exam and determines when alternative imaging modalities need to be obtained.

The role of routine use of duplex arteriography to diagnose thrombosis of popliteal artery aneurysm as a cause of acute lower extremity ischemia is investigated. In all, 109 patients (group 1) from 1994 to 1997 and 201 patients from 1998 to 2001(group 2) presenting with acute limb-threatening ischemia were studied. None of the group 1 patients underwent preoperative duplex arteriography, and no diagnosis of acute popliteal artery aneurysm thrombosis was made. Ten patients with acute ischemia due to thrombosed popliteal artery aneurysm were identified in group 2 when preoperative duplex arteriography was routinely performed. Urgent revascularization was performed based on the results of duplex arteriography. Six patients had functioning bypasses with a mean follow-up of 15.6 months. There were 3 deaths, 2 within 30 days and 1 after 2(1/2) years with functioning grafts. One patient was lost to follow-up. Routine use of duplex arteriography may provide the diagnosis and may identify the available outflow vessels for popliteal artery aneurysm.

OBJECTIVE: This study assessed whether the duplex ultrasound (DUS)-derived gray-scale median (GSM) of the most six distal portion of the occluded femoral-popliteal arterial segment can predict success of lumen re-entry for subintimal angioplasty. METHODS: During the last 3 years, 108 patients (62% men) with a mean age of 73 +/- 10 years underwent 116 primary attempted DUS-guided subintimal angioplasties of the femoral-popliteal segment. Preprocedural B-mode DUS images of the plaque at the most distal occlusion segment were digitalized and normalized using Photoshop (Adobe, San Jose, Calif) software and standard criteria (gray level, 0 to 5 for lumen blood and 185 to 190 for the adventitia on a linear scale of 0 to 255). Overall GSM of the plaque segment about 2 cm long, immediately before the planned re-entry point to the true arterial lumen, was used for retrospective correlation with procedure success and other clinical indicators. RESULTS: Mean plaque GSM for all cases was 22.5 +/- 12.6 (range, 3 to 60). The overall success rate of subintimal angioplasty procedures was 85%. Mean plaque GSM for 99 successful cases (18.4 +/- 7.8) was significantly lower than for 17 cases (46.4 +/- 8.1) where we failed (P < .0001). We failed in 90% of 19 cases with GSM >35, in 71% of 24 cases with GSM >20, and in 50% of 34 cases with GSM >25. There was no statistically significant difference (P = .45) between plaque GSM in 64 patients with diabetes (23.3 +/- 13.5) compared with 52 nondiabetic patients (21.5 +/- 11.4). Similarly, plaque GSM was not statistically different (P = .9) in 52 patients with renal insufficiency (22.7 +/- 13.2) compared with 64 patients with normal creatinine levels (22.4 +/- 12.2). At the 6-month follow-up, no statistically significant difference was found between mean GSM (17.8 +/- 7.8) in 47 stenosis-free cases compared with mean GSM (18 +/- 6.8) in 22 cases where severe restenosis (>70%) or reocclusion was identified by DUS scan (P = .4). CONCLUSIONS: Plaque echogenicity represented by DUS-derived GSM can be used to predict the success of primary subintimal femoral-popliteal angioplasties.

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.

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.

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.

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.