Cerebrovascular magnetic resonance angiography: a critical verification.

Because simultaneous noninvasive noncontrast imaging of cervical and cerebral vasculature and brain is possible with magnetic resonance angiography (MRA) and imaging (MRI), the following study was undertaken from July 1990 to January 1992. One hundred twenty-eight patients were examined with General Electric 1.5 Tesla MRI systems. Axially acquired volumetric three-dimensional time-of-flight MRA with 0.7 mm3 voxel size with regional maximum intensity projection after processing followed a two-dimensional time-of-flight localizing sequence. These two MRA sequences combined with spin-echo parenchymal brain MRI were compared with duplex scans, contrast angiograms, and surgical findings. Blinded readings by a radiologist and vascular surgeon allowed comparison of grades of luminal diameter narrowing (normal, mild, moderate, severe, and occluded) seen on MRA to be compared with those of Doppler and contrast angiography. Excluding 12 nondiagnostically imaged internal carotid arteries (10 MRA) and limiting duplex correlation to within 5 days of the MRA examination allowed critical appraisal of 182 internal carotid arteries. Exact correlation of grade of stenosis was obtained by the radiologist in 136 (74.7%) of 182 arteries and the surgeon in 138 (75.8%) of 182 arteries. Spearman rank correlation analysis found rank correlation coefficients of 0.88 (p < 0.001) and 0.83 (p < 0.001), respectively, for the radiologist and vascular surgeon. Disagreement one category apart was found by the radiologist in 35 studies (19.3%) and the surgeon in 28 studies (15.4%). Two or more grades of disagreement were found by the radiologist in 11 studies (6%) and the surgeon in 16 studies (8.8%). Contrast angiogram-MRA agreement was found in 86% of 36 internal carotid arteries. The degree of stenosis detected by MRA was concordant with surgical findings in 39 of 40 patients. Thus MRA emerges as a useful and accurate method of obtaining cerebrovascular evaluation in clinical practice.

Popliteal vascular trauma. A community experience.

Preventing amputation continues to be a significant challenge when popliteal vascular injuries occur. A retrospective review of cases from the San Diego County (California) Trauma System identified 108 patients with 76 blunt and 32 penetrating arterial injuries. The limb preservation rate was 88%; there were 13 amputations. The fracture-dislocated knee injury and close-range shotgun blasts were particularly limb threatening. In general, the trauma system achieved rapid evaluation of injuries and early operative intervention. All 13 patients who underwent amputations presented with signs of severe ischemia. Concomitant injuries to the popliteal vein, tibial nerves, and soft tissue were significantly more frequent in patients who underwent amputations. The importance of complete fasciotomy for compartment hypertension, early reconstructive management of soft-tissue injuries, and expeditious arterial repair, frequently without preoperative roentgenographic suite arteriography, is emphasized. An aggressive, multidisciplinary approach is required to achieve a functional extremity when popliteal vascular trauma occurs.

Zero operative mortality rate in 109 consecutive elective aortic operations performed by residents.

One hundred and nine consecutive elective abdominal aortic operations were performed at the Veterans Administration Medical Center San Diego between 1984 and 1987. All of the operating surgeons were residents in general surgery who were assisted by attending staff. The mean age of the patients was 66.1 years and 34 patients were 70.0 years or older. The indication for operation was aortic aneurysm in 69 and aortoiliac occlusive disease in 40. Fifteen patients underwent highly complex procedures. The mean duration of operation was 5.6 hours, mean aortic clamp time was 72 minutes and mean volume of blood replacement was 1,186 milliliters. There was no operative mortality. Twenty-nine patients had 32 nonfatal complications. Patency of the graft was 100 per cent at discharge. We conclude that excellent clinical results with complex elective aortic operations can be achieved by surgical residents with appropriate supervision.

Septic peripheral embolization from bacterial and fungal endocarditis.

Arterial embolization is second only to cardiac failure as a potentially lethal complication of acute infectious endocarditis. Embolization may be encountered with increasing frequency due to the prolongation of life afforded by antibiotics and cardiac valve replacement surgery. While distal organs are more often affected, peripheral embolization of the lower extremities is by no means rare. Over a two-year period, we have treated six patients with acute infectious endocarditis who developed lower extremity ischemia. Four patients had Gram positive bacterial endocarditis while two immunosuppressed patients developed fungal endocarditis. Treatment of all six patients included lower extremity embolectomy or bypass grafting and long-term intravenous antimicrobial or antifungal therapy. Cardiac valve replacement was required in all six patients. All lower extremities were successfully reperfused, and no patient required amputation. Although the four patients with bacterial endocarditis survived, the two patients with fungal endocarditis eventually died. In conclusion, aggressive use of arteriography, embolectomy, antimicrobial drugs, and cardiac valve replacement appear to offer the best chance for survival and limb salvage for arterial embolism related to endocarditis.

Vascular complications associated with orthopedic procedures.

Damage to vascular structures during orthopedic procedures occurs relatively infrequently; when it does occur, however, recognition and prompt intervention are essential. We report herein 11 vascular injuries secondary to orthopedic procedures encountered between 1978 and 1988. Two injuries occurred as a consequence of lumbar laminectomy, three as a result of total hip replacement, three secondary to open reduction and internal fixation of a fracture of a lower extremity, two secondary to attempted closed reduction of humeral fractures and one injury as a result of hip flexion contracture release. Injury occurred to three iliac arteries, three popliteal arteries, two brachial arteries, one femoral artery, one graft to femoral anastomosis and two iliac veins. Five arterial injuries were repaired primarily, one with a vein patch, while five required bypass grafts. One venous injury was repaired primarily and the other required placement of a Greenfield filter for thrombosis. Major complications were a result of diagnostic delay and subsequent ischemia in most patients. There were no deaths. We conclude that vascular injuries can occur as a result of laceration, compression or traction during orthopedic procedures as a result of the proximity of vascular structures to the spine, joints and long bones. Also, we conclude that injuries manifest themselves primarily as hemorrhage or ischemia; that excellent results can be obtained with prompt recognition and treatment; that angiography is useful in those with mild ischemia in whom diagnosis is delayed, and that preoperative documentation of the vascular status of patients is critical prior to orthopedic procedures.

Prospective analysis of carotid endarterectomy and silent cerebral infarction in 97 patients.

To determine the incidence of perioperative silent cerebral infarction, 97 patients who underwent carotid endarterectomy were prospectively studied with preoperative and postoperative computed tomograms. Thirty-one of 96 patients (32%) had findings of cerebral infarction on preoperative computed tomograms. Silent cerebral infarction was found preoperatively in 17 patients (18%) (lacunar infarction in 10, cortical infarction in five, both cortical and lacunar infarctions in one, and cerebellar infarction in one). Transient ischemic attacks occurred in 10 of the 17 patients with silent cerebral infarction; however, symptoms were appropriate to the site in only five of these 10 patients. Fourteen of the 17 patients with silent cerebral infarction had a hemodynamically significant carotid stenosis, and seven patients had an ulcerated plaque on preoperative angiogram. The incidence of these lesions was similar to that found in the group of 66 patients without cerebral infarction. Endarterectomy specimens revealed a higher but not significantly different incidence of ulcerated plaque in the silent cerebral infarction group. There were no perioperative deaths. Following surgery, one patient (1%) with a preoperative silent cerebral infarction suffered a transient ischemic attack, and two patients (2%) with normal preoperative computed tomograms developed permanent neurologic deficits with new cortical infarctions on postoperative computed tomograms. No new silent cerebral infarctions were found on postoperative computed tomograms in any of the 97 patients. Our data suggest that silent cerebral infarction is a common preoperative finding with an as-yet unclear etiology and that carotid endarterectomy does not appear to be a cause.

The changing epidemiology of pseudoaneurysm. Therapeutic implications.

To elucidate newly emerging trends in pseudoaneurysm causation, 57 patients with 81 pseudoaneurysms were reviewed. Only two (8%) of 24 pseudoaneurysms treated surgically before 1977 were infected, whereas 17 (30%) of 57 treated during the past decade were infected. There were four deaths among 12 patients (33%) with infected pseudoaneurysms compared with only one death among 45 patients (2%) with noninfected pseudoaneurysms. All five amputations were consequences of infected pseudoaneurysms. We conclude that (1) infection as a cause of pseudoaneurysm is increasing, (2) mortality and limb loss are now confined almost exclusively to cases involving infection, and (3) the current approach to pseudoaneurysm should include a high index of suspicion in patients at risk for infection, increased use of newer diagnostic scans, and an aggressive surgical attack on infected pseudoaneurysms that may require complete graft excision and extra-anatomic bypass.

Indium 111-labeled white blood cell scans after vascular prosthetic reconstruction.

The clinical value of indium 111-labeled white blood cell (WBC) scanning done after vascular graft procedures was investigated to differentiate noninfectious postoperative inflammation associated with graft incorporation from early prosthetic graft infection. Indium 111-labeled WBC scans were initially obtained in 30 patients before discharge from the hospital and during the subsequent follow-up period (334 days). Fourteen of 30 patients (47%) had normal predischarge scans that included all 10 patients who had grafts confined to the abdomen and 4 of 20 patients (20%) who had grafts arising or terminating at the femoral arteries (p less than 0.05). Sixteen of 30 patients (53%) discharged with abnormal initial indium 111 WBC scans underwent serial scanning until the scan normalized or a graft complication developed. All of the 16 patients had grafts involving the groin region. Abnormal indium 111 uptake in the femoral region continued for a mean 114 days without the development of prosthetic graft infections. The sensitivity of indium 111-labeled WBC scans for detecting wound complications was 100%, whereas the specificity was 50%. Thus, the accuracy of the test was only 53%. We conclude that (1) abnormal indium 111 WBC scans are common after graft operations involving the groin region but are unusual after vascular procedures confined to the abdomen, and (2) in the absence of clinical suspicion, the indium 111-labeled WBC scan does not reliably predict prosthetic graft infection because of the low specificity of the test in the early postoperative period.

Epithelial impedance analysis in experimentally induced colon cancer.

Epithelial impedance analysis was used to measure the alterations in resistance of the large bowel in a murine model of large bowel cancer. The technique was able to resolve the epithelial resistance from the total resistance of the bowel wall. A progressive decrease in resistance of the bowel epithelium occurs during carcinogenesis induced with dimethyhydrazine. About a 21% decrease in epithelial resistance from 22.0 +/- 1.3 omega.cm-2 to 17.5 +/- 1.1 omega cm-2 (p less than 0.025) was observed after 20 wk of carcinogen administration. The sensitivity of the technique in detecting altered epithelial resistance in premalignant bowel mucosa was improved by examining the impedance profile in a sodium-free Ringer's solution where the epithelium of control colons had a resistance of 24.4 +/- 1.8 omega.cm-2 compared with 19.0 +/- 1.1 omega.cm-2 (p less than 0.02) in colons from animals treated for only 4 wk with the carcinogen. Epithelial impedance analysis would seem to be a sensitive technique capable of identifying changes in the electrical properties or the large bowel early in disease states.

"Coral reef" atherosclerosis of the suprarenal aorta: a unique clinical entity.

Localized obstruction in a suprarenal aorta of normal diameter is rare. Between 1970 and 1983, nine patients (all women, mean age 51 years) required aortic reconstruction to relieve severe lower extremity ischemia (nine patients), hypertension (nine), visceral ischemia (two), and congestive heart failure (three) caused by an eccentric, heavily calcified polypoid lesion originating from the posterior surface of the suprarenal aorta. This mass typically began at the level of the diaphragm and extended to the level of the renal arteries, almost totally occluding the aortic lumen. The rock-hard, irregular, gritty, whitish surface strongly resembled a coral reef. Elective revascularization was carried out in eight patients, and an emergency procedure was necessary in one patient who had acute aortic thrombosis with catastrophic visceral, renal, and lower extremity ischemia. The suprarenal atheroma was removed en bloc through a retroperitoneal thoracoabdominal aortic endarterectomy. Concomitant aortoiliofemoral revascularization was necessary in seven patients (five prosthetic grafts, two endarterectomies). Two patients died postoperatively. The seven long-term survivors remain asymptomatic at a mean follow-up interval of 4 years after revascularization, without evidence of recurrence of this lesion. Suprarenal "coral reef" atherosclerosis should be considered if visceral, renal, and limb ischemia is not adequately explained by the arteriographic pattern of conventional atherosclerosis. This unusual atheroma exhibited extensive calcification and metaplastic bone formation, although its precise pathophysiology remains to be defined.