Paul G. Bove

Diagnosis of total internal carotid occlusions with duplex ultrasound and ultrasound contrast

It remains a significant technical challenge for duplex ultrasound to accurately differentiate between total and near total internal carotid artery (ICA) occlusions. We have evaluated the efficacy of an ultrasound contrast agent combined with improved imaging techniques in patients with suspected carotid artery occlusions. Patients identified by conventional duplex ultrasound between January and August 2003 as having a possible ICA occlusion were eligible for study. A 1 mL bolus of ultrasound contrast agent was injected into a 50 mL bag of normal saline and given intravenously at a rate of approximately 4–5 mL/minute. Ultrasound imaging and spectral Doppler analysis were done using tissue harmonic imaging for optimum contrast agent to soft tissue discrimination, or with the direct B-mode imaging of blood flow to maximize the brightness of the circulating contrast agent. Ten patients were identified, 6 men and four women with a mean age of 68.3 years. Nine suspected total ICA occlusions were unilateral and 1 was bilateral. Imaging with contrast agent confirmed occlusion of the ICA in 7 of 10 patients; 3 patients had near-total occlusion with flow detected in the distal ICA by spectral and color Doppler. All 3 of these near-total occlusions were ultimately confirmed by either conventional or magnetic resonance carotid angiography. The contrast agent was most beneficial in improving the detection of minimal flow beyond a severe stenosis and in evaluating flow dynamics in the presence of severely calcified plaque. We conclude that the use of an ultrasound contrast agent with newer duplex ultrasound imaging techniques can reliably distinguish total from near-total internal carotid artery occlusions. Future prospective studies should be able to define the efficacy of ultrasound contrast agents in improving the overall diagnostic accuracy of duplex ultrasound in technically difficult cases and in patients with complex peripheral vascular disease.

Three-dimensional vascular imaging using Doppler ultrasound

BACKGROUND We have evaluated the efficacy of using three-dimensional reconstruction of amplitude Doppler imaging data to quantitatively assess carotid artery bifurcation stenoses. METHODS Sixty-four consecutive frames of amplitude (power) Doppler images are stored to be reassembled into a three-dimensional image representing the patent lumen. These images can then be rotated by any angle necessary to clearly view the vascular anatomy and to make quantitative ultrasound caliper measurements of the stenotic lumen and normal vessel caliber. RESULTS Three-dimensional Doppler images accurately classified 53 of 61 vessels (87%) into categories of stenosis compared with angiography. All stenoses with >60% diameter reduction were detected and classified as such, for a sensitivity of 100%. CONCLUSIONS Three-dimensional vascular imaging based on amplitude (power) Doppler data provides an accurate noninvasive technique for quantitative diagnosis of carotid bifurcation atherosclerotic disease, with selectable viewing projections that eliminate vessel overlap and other artifacts, and complements the hemodynamic data already available with two-dimensional duplex ultrasound.

Simultaneous stent-graft repair of thoracic and infrarenal abdominal aortic aneurysms.

Purpose: To describe a technique for concomitant endovascular stent-graft repair of thoracic and infrarenal abdominal aortic aneurysms. Case Report: A 68-year-old man was found to have concomitant thoracic and abdominal aortic aneurysms. Both of the aneurysms were excluded successfully in one procedure using Talent stent-grafts. The patient tolerated the procedure well and was discharged on postoperative day 4. Aside from an infected groin wound, the patient did not have any complications. Computed tomographic scans at 6, 12, and 18 months showed proper position of both stents without evidence of endoleak. Conclusions: Simultaneous endovascular treatment of thoracic and infrarenal abdominal aortic aneurysms may represent a viable alternative for therapy in some patients.

Safety of Contemporary Percutaneous Peripheral Arterial Interventions in the Elderly Insights From the BMC2 PVI (Blue Cross Blue Shield of Michigan Cardiovascular Consortium Peripheral Vascular Intervention) Registry

OBJECTIVES This study sought to evaluate the effect of age on procedure type, periprocedural management, and in-hospital outcomes of patients undergoing lower-extremity (LE) peripheral vascular intervention (PVI). BACKGROUND Surgical therapy of peripheral arterial disease is associated with significant morbidity and mortality in the elderly. There are limited data related to the influence of advanced age on the outcome of patients undergoing percutaneous LE PVI. METHODS Clinical presentation, comorbidities, and in-hospital outcomes of patients undergoing LE PVI in a multicenter, multidisciplinary registry were compared between 3 age groups: < 70 years, between 70 and 80 years, and ≥ 80 years (elderly group). RESULTS In our cohort, 7,769 patients underwent LE PVI. The elderly patients were more likely to be female and to have a greater burden of comorbidities. Procedural success was lower in the elderly group (74.2% for age ≥ 80 years vs. 78% for age 70 to < 80 years and 81.4% in patients age < 70 years, respectively; p < 0.0001). Unadjusted rates of procedure-related vascular access complications, post-procedure transfusion, contrast-induced nephropathy, amputation, and major adverse cardiac events were higher in elderly patients. After adjustment for baseline covariates, the elderly patients were more likely to experience vascular access complications; however, advanced age was not found to be associated with major adverse cardiac events, transfusion, contrast-induced nephropathy, or amputation. CONCLUSIONS Contemporary PVI can be performed in elderly patients with high procedural and technical success with low rates of periprocedural complications including mortality. These findings may support the notion of using PVI as a preferred revascularization strategy in the treatment of severe peripheral arterial disease in the elderly population.

Gastrointestinal Complications Following Infrarenal Endovascular Aneurysm Repair

Gastrointestinal complications are known to occur after open elective aortic aneurysm repair. This leads to increased morbidity, mortality, length of stay, and hospital costs. The authors hypothesize a change in the character and/or frequency of early postoperative gastrointestinal complications after endovascular aneurysm repair as compared to open abdominal aortic repair. This is a retrospective cohort study in which the medical records of 153 consecutive patients who underwent endovascular infrarenal aneurysm repair from November 1998 to August 2001 were reviewed for gastrointestinal complications. Of these 153 patients, 9 (5.9%) had postoperative gastrointestinal complications. Three patients (1.9%) underwent exploratory laparotomy for small bowel obstruction. One patient had had a right hemicolectomy for cancer 2 years before stent graft placement. This patient needed a partial small bowel resection. One patient had had a right hemicolectomy 4 months before stent graft placement; he had lysis of adhesions with no bowel resection. A third patient underwent operative repair of an incarcerated inguinal hernia. Six patients (3.9%) had paralytic ileus that was treated by nasogastric tube or observation resulting in an extended hospital length of stay. All cases of ileus resolved without any operative intervention. No patients in this series developed any intestinal ischemia, pancreatitis, cholecystitis, or gastrointestinal bleeding. After endovascular aneurysm repair, gastrointestinal complications such as ileus and postoperative small bowel obstruction are seen with a similar frequency as after open aortic repair. This occurs despite the absence of a laparotomy with mesenteric dissection and evisceration. In this series, these complications are associated with longer hospital length of stay but no increased mortality rate. No instances of colonic ischemia, pancreatitis, cholecystitis, or gastrointestinal bleeding were seen in this series.

Hemodynamic sequelae of combined arteriovenous injury in an experimental canine hindlimb model: Venous ligation vs. repair

The hemodynamic effects of combined venoarterial injury and stasis were studied in the hindlimbs of 10 dogs. Femoral arterial blood flow and pressure, peripheral venous pressure, and peripheral resistance were measured after the restoration of blood flow following venoarterial injury and a 4-hour period of occlusion for up to 72 hours. In one limb of each animal both the artery and vein were repaired, whereas only the artery was repaired in the other limb and the vein was ligated. Arterial blood flow was similar in both groups but was significantly diminished from baseline for the first 30 minutes after restoration of blood flow, but then it became significantly reduced in the limbs with venous ligation when compared with values in those with venous repair. By 72 hours the flow on both sides returned to control values. Peripheral venous hypertension and edema occurred in all 10 limbs with venous ligation and persisted for the 72-hour experimental period. In the 10 limbs with venous repair, edema occurred in four and venous hypertension in none. The peripheral resistance was elevated on both sides; this elevation persisted for 75 minutes and then dropped to control values. None of the repaired arteries and only one repaired vein thrombosed during the experiment. Combined venous and arterial occlusion for 4 hours reduced both the amount of arterial flow and its subsequent rate of increase compared with changes seen after release of an actue venous occlusion. The rate of increase was enhanced by repair of the affected venous segment compared with simple venous ligation.

Angiosarcoma Involving Native Abdominal Aortic Aneurysm Sac after Endograft Repair

Primary angiosarcoma of the aorta is a rare malignancy that is characterized by rapid proliferation and propensity for metastasis. It has been reported only 35 times in the surgical literature. This case report presents a 66-year-old man diagnosed with angiosarcoma of his native aorta 7 years after endograft repair of an abdominal aortic aneurysm. We then reviewed the world surgical literature for occurrence, tumorigenic studies, prognosis, and management of aortic angiosarcoma. Because native aortic tissue is retained after endovascular repair of an abdominal aortic aneurysm, the treating physician should have an awareness of this pathology and entertain the diagnosis as appropriate.

Intentional coverage of a main renal artery during endovascular juxtarenal aortic aneurysm repair in symptomatic high-risk patients.

Purpose: To describe the efficacy and morbidity of intentionally covering a main renal artery during symptomatic juxtarenal endovascular aneurysm repair (EVAR). Case Reports: Two patients with symptomatic juxtarenal abdominal aortic aneurysm (AAA) were felt to be at prohibitive risk for open repair. Each underwent EVAR with intentional coverage of 1 main renal artery to achieve adequate proximal hemostatic seal. One patient died at 24 months; the second is symptom-free at 10 months. Both aneurysms initially decreased in diameter. Both patients had increased serum creatinine and required increased therapy for hypertension, but neither required hemodialysis. Renal volume decreased 48.7% and 68.0%, respectively. Conclusion: Intentional coverage of a main renal artery during EVAR for a symptomatic juxtarenal aneurysm resulted in effective short-term AAA repair with no need for dialysis. Despite the increased requirement for antihypertensive medications and the observed decline in renal function, this technique provides an option for treatment of this difficult patient subset.

Colorectal complications following cardiac surgery

PURPOSE: This study was undertaken to assess colorectal complications following cardiopulmonary bypass surgery. METHOD: This is a retrospective review of 5,801 patients who underwent 5,801 cardiopulmonary bypass procedures from 1985 to 1991. Patients were evaluated for type of bypass procedure, postoperative colorectal complications, age, sex, bypass time, aortic cross-clamp time, electivevs.emergency cases, uses of intra-aortic balloon pump, perioperative hypotension, and use of vasopressors. Statistical analysis was performed using chi-squared analysis and Studentst-test. RESULTS: Nineteen of the 5,801 patients developed 19 colorectal complications, a prevalence of 0.3 percent for the initial hospital stay following bypass surgery. Mortality in those with complications was 37 percent (7/19). Of the 19 complications, 9 (47 percent) followed coronary artery bypass grafting, whereas 10 (53 percent) followed valve replacement or combined coronary artery bypass grafting with other cardiac procedures. Five (26 percent) of the complications followed emergency cases, whereas 14 (74 percent) followed elective cases. Average age of those with complications was 698 years, compared with 63.2 years for those without complications. Average aortic cross-clamp time for those with complications was 71 ±25 minutes; pump time was 106±34 minutes. That was significantly higher than in those without complications. Nine (47 percent) patients with complications required vasopressors during the perioperative period, whereas eight (42 percent) suffered prolonged hypotension (systolic blood pressure, <90 mmHg). CONCLUSIONS: It appears that increased age, valve replacement, or combined cardiac procedures, emergency procedures, and prolonged aortic cross-clamp and bypass pump times are risk factors for development of colorectal complications. Hypoperfusion, as suggested by prolonged pump times, clamp times, and emergency procedures may be a possible cause for development of colorectal complications.