Stanton N. Smullens

Multicenter validation study of real-time (B-mode) ultrasound, arteriography, and pathologic examination.

The ability of high-resolution ultrasound, angiography, and pathologic examination of endarterectomy specimens to identify and quantitate atherosclerosis was compared in a five-center study. The carotid bifurcation in 900 patients was evaluated by angiography and ultrasound. In 216 cases, high-quality endarterectomy specimens were available for comparison with the preoperative images. All comparisons were made in a blinded fashion. Results indicate that ultrasound is able to differentiate angiographically normal from abnormal arteries with a sensitivity of 88% (1077 of 1233 arteries) and accuracy of 79% (1251 of 1578 arteries). Angiographic stenoses equal to or greater than 50% diameter were accurately identified by ultrasound imaging in 72% (1133 of 1578 arteries) of cases, and this was improved by the addition of other functional data (i.e., Doppler spectral analysis and oculoplethysmography). There was only modest correlation of absolute measurements of lesion width, minimal lumen, and standard lumen by the two imaging techniques (r = 0.28 to 0.55). Ultrasound measurements of lesion width were on the average 2 mm greater than those of angiography. The lumen averaged 1.5 mm larger when measured by ultrasound techniques. In the subset in which data were available from endarterectomy specimens, ultrasound showed the best correlation with lesion width (mean difference -1.1 mm) and angiography correlated best with minimal lumen (mean difference -0.1 mm). Neither examination consistently identified ulcerated plaques. Although ultrasound imaging alone has limited usefulness in quantitating luminal stenosis, this can be improved by the use of Doppler spectral analysis and oculoplethysmography. Ultrasound is superior to angiography for quantifying atherosclerotic plaque (lesion width) and will be an important tool for further study of atherosclerotic lesions.

Long-term outcome following sympathectomy for complex regional pain syndrome type 1 (RSD)

We performed a retrospective study of 29 patients with CRPS1 (RSD) who were initially examined between 1983 and 1993, and had either transthoracic (lower third of stellate ganglia to T3) or lumbar (L2-L4) sympathectomy. The patients were followed from 24 to 108 months after surgery. Patients with unsuccessful surgical outcomes had significantly longer duration of symptoms before surgery (median, 36 months) than those with successful outcomes (median, 16 months) by Wilcoxon rank sum test (chi2=8.69, df=1, P<0.01). All seven patients (100%) who had sympathectomy within 12 months of injury, nine of 13 patients (69.2%) who had sympathectomy within 24 months of injury, and only four of nine patients (44.4%) who had sympathectomy after 24 months of injury obtained permanent (greater than 24 months) symptom relief. Patient age, sex, occupation, site of injury, type of injury, presence of trophic changes, and duration of follow-up were not significantly related (P>0.05) to surgical outcome.

Magnetic resonance chemical shift imaging and spectroscopy of atherosclerotic plaque.

An in vivo magnetic resonance imaging (MRI) technique for identification and characterization of atherosclerotic plaque was assessed in animal and human models. Atherosclerosis was induced in the abdominal aorta of four rabbits by a combination of balloon denudation and a high cholesterol diet. In vivo conventional spin-echo and fat/water suppressed images of the rabbit aortae were obtained at 1.5 T. Chemical shift imaging (CSI) was achieved using a hybridization of selective excitation and modified Dixon techniques. These techniques were then used to obtain images of atherosclerotic lesions in the carotid arteries of four patients prior to endarterectomy. The MRI results were corroborated by histologic and high-resolution proton MR spectroscopic (8.5 T) analysis of rabbit aorta, human carotid endarterectomy, and six additional human superficial femoral and iliac atherectomy specimens. All animal and human lesions were classified as either fatty streaks or fibrotic plaque. When compared to conventional spin-echo images, fat suppression by CSI substantially improved the measured contrast-to-noise ratio between plaque and vessel lumen, and enhanced its discrimination from periadventitial fat. In contrast, water suppression eliminated visualization of plaque due to the negligible amount of isotropic (liquid-like) signal from the immobilized lesion lipids. Magnetic resonance spectroscopy corroborated the CSI results by demonstrating broad, ill-defined fat resonances characteristic of nonmobile lipids in both human and rabbit atherosclerotic lesions. These findings indicate that in vivo MRI of plaque is technically feasible and can be markedly improved using chemical shift imaging.

Preoperative embolization of retroperitoneal hemangiopericytomas as an aid in their removal

The first reported cases of preoperatively embolized hemangiopericytomas are presented. Both lesions presented in the retroperitoneum where most lesions are now considered to be malignant. In the past, the highly vascular nature of these tumors has made resection in these areas difficult. Since the angiographic picture of hemangiopericytomas is now thought to be specific, it became feasible to add preoperative embolization to the overall management of these cases. In the first case, the diagnosis had been established 15 years previously. When first seen at Thomas Jefferson University Hospital, extensive bone destruction of the sacrum and lumbar vertebrae were present. Preoperative Gelfoam embolization aided in the palliative debulking of the tumor at operation. With this experience, preoperative embolization became part of the management in the second case and aided in the complete surgical removal of the tumor. Radiation therapy in the dosage of 5000 rad was given postoperatively in this case and should also be part of the treatment plan for these lesions. Cancer 50:1870‐1875, 1982.

Comparison of Doppler US and CT angiography for evaluation of renal artery stenosis

Rationale and Objectives. The authors compared Doppler ultrasound (US) with computed tomographic (CT) angiography in the evaluation of stenosis of the main renal artery. Materials and Methods. Fifty-six patients who had undergone conventional angiography of the renal arteries participated in a prospective comparison of Doppler US (45 patients) and CT angiography (52 patients). US evaluation included both the main renal artery and segmental renal arteries. Results. There were 27 main renal arteries with at least 50% stenosis in 20 patients. In 36 patients, there was no significant stenosis. All cases of main renal artery stenosis detected with Doppler US of the segmental arteries were also identified with Doppler US of the main renal artery. The by-artery sensitivity (63%) of US of the main renal artery was greater than that (33%) of US of the segmental arteries. CT angiography was more sensitive (96%) than Doppler US (63%) in the detection of stenosis, but the specificity of CT (88%) was similar to that of US (89%). The difference in the area under the receiver operating characteristic curve (AUC) between CT (AUC = 0.94) and US (AUC = 0.82) was statistically significant (P = .038). Conclusion. Doppler US of the main renal artery is more sensitive than Doppler US of segmental arteries in the detection of stenosis. CT angiography is more accurate than Doppler US in the evaluation of renal artery stenosis.

Reliability and validity of the migraine therapy assessment questionnaire.

Objective.—To determine the reliability and validity of the Migraine Therapy Assessment Questionnaire (MTAQ).

Intravenous labetalol for the treatment of hypertension after carotid endarterectomy

Hypertension after carotid endarterectomy has a variable incidence ranging up to 56%. Blood pressure (BP) control is essential due to possible increased risk of morbidity from neurologic deficits or cardiovascular complications. This study evaluated intravenous labetalol for control of hypertension after carotid endarterectomy. Sixty ASA II-IV patients were studied; 20 developed BP high enough for treatment with labetalol. The anesthetic technique was standardized. Labetalol was administered at the conclusion of surgery as a 20-mg bolus over two minutes followed by 40 mg every 10 minutes until the desired BP was achieved (BP less than or equal to 10% above average preoperative BP or less than 150 mmHg, systolic) or 300 mg had been given. The mean total dose of labetalol was 42.0 +/- 33.0 mg (mean +/- SD) and mean time to reach the desired BP was 16.2 +/- 21.4 minutes. Systolic, diastolic, mean arterial pressure and heart rate significantly decreased after labetalol treatment and remained so for the remainder of the 180-minute study period. There was no hypotension, bradycardia, evidence of myocardial ischemia or central nervous system dysfunction present with labetalol treatment. Blood samples were obtained for determination of plasma renin activity, epinephrine, and norepinephrine in 10 patients who developed hypertension and received labetalol, and 10 patients who did not develop hypertension. In the patients developing hypertension, there was a significant elevation in epinephrine just before treatment, that decreased by 30 minutes after treatment. Norepinephrine levels became significantly elevated five minutes after labetalol treatment in the group with hypertension and remained elevated for 120 minutes. Concomitantly, there was a significantly lower plasma renin activity seen in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term follow-up of reoperative carotid surgery

BACKGROUND We examined our long-term results of carotid reoperation to identify risk factors for morbidity and secondary recurrence. METHODS Medical record review revealed 27 patients had reoperative surgery for recurrent stenosis. Demographics, operative details, pathology, clinical outcome, and follow-up imaging results were reviewed. RESULTS No neurologic deficits and no mortalities were noted perioperatively. Long-term follow-up (average 54 months) revealed an 85% 5-year and 29% 10-year estimated survival. The 5- and 10-year estimated neurologic event rates were 15% and 35%, respectively. These included 3 ipsilateral strokes and 1 ipsilateral TIA; only the TIA involved secondary restenosis. Follow-up imaging revealed a 21% incidence of secondary restenosis, occurring more frequently in patients with hyperlipidemia (P < 0.05) and previous contralateral endarterectomy (P < 0.05). CONCLUSIONS (1) Reoperation provides long-term protection from stroke due to recurrent stenosis. (2) Secondary restenosis rates appear higher than those for primary surgery. (3) Hyperlipidemia and contralateral endarterectomy are risk factors for secondary restenosis.

Ruptured abdominal aortic aneurysm with horseshoe kidney

A case of ruptured abdominal aortic aneurysm associated with horseshoe kidney is presented. Two aspects of the operation are discussed: the vascular supply to the kidney and isthmus and the division of the isthmus. It is important in handling these cases either on an emergency basis or electively to be aware of the various vascular anomalies.

Computer simulation of blood flow using short te magnetic resonance angiography

Using computer simulation of pulsatile blood flow and magnetic resonance angiography (MRA), we investigated the hemodynamic factors leading to the formation and evolution of 1) atherosclerotic plaque in carotid arteries, and 2) aneurysms in the abdominal aorta. Phantom and patients were imaged by MRA, color Doppler and/or digital subtraction angiography (DSA). Computer modelling was carried out by finite element analysis to solve the Navier-Stokes equation. In the analyzed vessels, voxels representing pathology were digitally removed. Local wall shear stress and pressure were also calculated as a function of a cardiac cycle. There was general agreement between MRA, color Doppler, DSA and computer simulation in both phantom and in-vivo experiments. In MRA, the best results were achieved by short TE, thin slice 2D “time-of-flight” technique, which was least susceptible to the changes in velocity profiles, and best correlated with Doppler and computer simulation. The hemodynamic information obtained from analyzed carotid arteries predicted that during late systole, flow separation exists at the exact locations from where the plaque voxels were removed. We were also able to predict the location of abdominal aortic aneurysm and its evolution toward the distal vessel intima. In conclusion, MRA accurately depicted flow disturbances, and computer simulation of blood flow proved to be a good predictor of the development of vascular pathology.