Vascular ultrasound.

Surgeon-interpreted diagnostic ultrasound has become the preferred screening test and often the definitive test for the diagnosis of arterial stenosis, aneurysm, and venous thrombosis. As a modality for surveillance, its noninvasive quality makes it particularly appealing as the test of choice to screen patients for abdominal aortic aneurysms or to perform follow-up examinations on those patients with a carotid endartectomy or in situ bypass grafts. The increasing reliance on intraoperative duplex imaging of vascular procedures demands that the surgeon learn the skills to perform the studies without a technologist or radiologist to interpret the examination.

Five-year follow-up of prophylactic vena cava filters in high-risk trauma patients.

OBJECTIVE: To assess the short- and long-term outcomes of vena cava filter (VCF) placement for prophylaxis against pulmonary embolism in patients at high risk due to trauma. DESIGN AND SETTING: Case series at a level I trauma center. PATIENTS: Patients were considered for prophylactic VCF placement if they met 1 of the injury criteria--spinal cord injuries with neurologic deficit, severe fractures of the pelvis or long bone (or both), and severe head injury--and had a contraindication to anticoagulation. INTERVENTION: Vena cava filters were placed percutaneously by the interventional radiologists when the acute trauma condition was stabilized following admission. MAIN OUTCOME MEASURES: Filter tilt of 14 degrees or more, strut malposition, insertion-related deep vein thrombosis, pulmonary embolism, or inferior vena cava patency. RESULTS: There were 132 prophylactic VCFs placed. A 3.1% rate of insertion-related deep vein thrombosis occurred, all of which were asymptomatic. Filter tilt occurred in 5.5% of patients and strut malposition in 38%. Three cases of pulmonary embolism (1 fatal) occurred in a prophylactic VCF, and all patients had either filter tilt or strut malposition. The risk of pulmonary embolism developing was higher in those patients with filter tilt or strut malposition than in those who did not have these complications (6.3% vs 0%; P=.05; Fisher exact test). The 1-, 2-, and 3-year inferior vena cava patency rates (+/-SD) were 97%+/-3%. CONCLUSIONS: Prophylactic VCF can be placed safely with an acceptable rate of insertion-related deep vein thrombosis and long-term inferior vena cava patency. Patients with prophylactic VCF remain at risk for pulmonary embolism if the filter is tilted 14 degrees or more or has strut malposition. In such patients, consideration should be given to placing a second filter.

Effects of hypertension and propranolol upon aneurysm expansion in the Anidjar/Dobrin aneurysm model.

Propranolol has been suggested to slow aortic aneurysm (AAA) expansion by a mechanism independent of simple blood pressure (BP) reduction. To investigate this hypothesis, we designed a series of experiments to examine the effects of hypertension and propranolol upon AAA expansion. Using an established animal model, we induced AAA in normotensive and genetically hypertensive rats by perfusion of the isolated infrarenal aorta with elastase for two hours. Systolic tail BP was monitored with a plethysmograph. AAA size was measured directly with a micrometer on postoperative days 7 and 14. All data are expressed as the mean +/- standard deviation (SD). BP (mmHg) was significantly higher in hypertensive rats: 164 +/- 15 versus 119 +/- 7 (p < 0.001). AAA were also significantly larger in hypertensive rats with a mean expansion rate (mm/day) nearly twice that of normotensive animals: 0.13 +/- 0.09 versus 0.07 +/- 0.03. In a second series of animals, propranolol treatment was compared to placebo. In those animals, hypertensive propranolol-treated rats had significantly smaller AAA than placebo-treated controls (p < 0.05). There was no difference in normotensive animals but these rats had an unexplained paradoxical rise in BP with treatment. In this model, hypertension increases the expansion rate of AAA. Propranolol reduced the size of AAA in hypertensive animals, at least in part because of a decrease in BP. Other possible mechanisms of propranolol's action may be operative and require further study.

Anti-CD 18 monoclonal antibody slows experimental aortic aneurysm expansion.

PURPOSE: Inflammation has been implicated as a contributing factor in the expansion of abdominal aortic aneurysms (AAA). To test this hypothesis, we examined the effects of a monoclonal antibody (MAB) to the leukocyte CD18 adhesion molecule on the expansion of experimental AAA. METHODS: Aneurysms were induced by perfusion of an isolated segment of the infrarenal aorta with elastase in 22 normotensive (WKY) and 17 genetically hypertensive (WKHT) rats. Animals of both strains were randomly allocated to control or MAB-treated groups (MAB, 5 microgram/100 gm body weight intraperitoneally, daily, beginning on the operative day for a total of four doses). The activity of the MAB against rat leukocytes had first been determined by in vitro immunofluorescence flow cytometry. Aortic size was directly measured initially and on day 14. At that time, a segment of aorta was stained with hematoxylin and eosin and mononuclear leukocytes and neutrophils were counted in each of 10 microscopic fields (400X). RESULTS: The initial aortic size in all animals was 1.11+/-0.15 mm. All groups developed aneurysms significantly larger than the initial aortic size (p<0.01). However, the MAB-treated animals had significantly smaller aneurysms than the untreated controls (mm): WKY: 3.63+/-1.26, WKY-MAB: 2.08+/-0.30, WKHT: 4.54+/-1.86, WKHT-MAB: 2.37+/-0.40, p<0.0001. There also were significantly fewer monocytes in the MAB-treated normotensive rats: WKY:35.5+/-29.9, WKHT:40.6+/-28.8, WKY-MAB: 8.9+/-8.5, WKHT-MAB: 32.3+/-25.7, p=0.03. Neutrophil counts did not differ significantly between the groups. CONCLUSIONS: Treatment with anti-CD18 monoclonal antibody slows the expansion of AAA in this experimental model. The associated inflammatory process at day 14, as indicated by monocyte infiltration, is reduced, but this effect may be opposed by the presence of hypertension. Further evaluation of the role of leukocytes and adhesion molecules in the expansion of AAA is warranted.

Practical equations to predict claudication pain distances from a graded treadmill test.

Treadmill testing is used to estimate the severity of claudication, but routine use is not practical or cost-effective in all settings. Thus, the purposes of this study were: (1) to develop and cross-validate prediction equations for treadmill claudication pain distances in a heterogeneous cohort of peripheral arterial occlusive disease patients, and (2) to determine if the regression equations were more accurate in assessing claudication distances than self-reported distances of patients. Medical history, vital signs, resting ankle/brachial systolic pressure index (ABI), and claudication distances during a graded treadmill test were obtained on a validation group of 178 claudicants and on a cross-validation group of 94 claudicants. The independent predictors of claudication pain distances of the validation group were ABI, body mass index, gender, and current smoking status, with multiple correlation coefficients of R = 0.73 and R = 0.82 for the distances to onset and to maximal pain, respectively. These equations were successfully cross-validated on an independent group of claudicants, as the predicted distances to onset of claudication pain (167.2 +/- 102.6 m) and to maximal pain (354.6 +/- 154.3 m) were similar (p = 0.99) to measured distances (169.1 +/- 127.8 m and 356.6 +/- 181.0 m, respectively). However, the self-reported distances to onset (89.5 +/- 126.3) and to maximal claudication pain (189.2 +/- 284.3) were 1-2 blocks less than either the measured or predicted distances (p < 0.01). It is concluded that claudication pain distances during an incremental treadmill test can be more accurately estimated from a composite of variables obtained during medical screening than by relying on the self-report of patients. Consequently, in clinical settings where treadmill testing is impractical, the functional severity of claudication can be assessed without exercise testing.

Patterns of splenic injuries seen in skiers.

Splenic rupture secondary to skiing appears to fall into two distinct epidemiological patterns: high-speed impact with stationary objects and simple falls (mogul injury). Of 18 splenic injuries seen at a referral hospital over 12 years, six were high-speed collisions with trees, lift towers or other solid objects. Twelve were low-speed falls impacting on moguls, the ski trail or low-speed impact with a trailside object (stump or rock). Those who sustained low-speed injuries frequently skied down the mountain afterwards without assistance (8/12), and had no other significant concomitant injuries other than minor renal contusions compared with the collision group (P < 0.005). The rate of splenic salvage was also higher in this group than in the collision group (68 per cent vs 17 per cent). The six high-speed collision splenic injury victims were all transported down the mountain by toboggan, and all had significant associated injuries. The incidence of concomitant renal injuries with splenic injuries in both groups was higher than in other reported series (10 of 18 patients). Some of those who skied down the mountain themselves sought medical attention only when they experienced haematuria. There were no significant differences in the length of stay in hospital, or intensive care units (ICU), or transfusion requirements or complications between groups. It is suggested that those who ski down the mountain themselves and present in a delayed fashion to medical/first aid facilities may still have serious abdominal injury but have a potentially higher rate of spleen salvage.

Prolonged warm ischemia and limb survival: case report.

A 21-year-old woman sustained a supracondylar crush injury of her arm. The extremity underwent severe ischemia for more than 16 hours after an unsuccessful brachial artery repair. The forearm muscles became rigid and the fingers could not be extended passively. Clinically these findings were felt to be similar to rigor mortis. Despite this dismal picture, secondary revascularization resulted in a highly functional hand with no loss of digits. Desperate attempts at revascularization in isolated extremity injury may be successful, despite prolonged warm ischemia time.

Expansion of aortic aneurysms is reduced by propranolol in a hypertensive rat model.

PURPOSE: It has been suggested that propranolol has unique effects that slow aneurysm expansion by remodeling the structural proteins of the aorta. These effects are believed to be independent of blood pressure reduction, a hypothesis we tested in this investigation with a rat model of abdominal aortic aneurysm (AAA). METHODS: With an established model, AAA were induced in normotensive Wistar-Kyoto (WKY) rats and genetically hypertensive Wistar-Kyoto (WKHT) rats by perfusing an isolated segment of the infrarenal aorta with elastase. A propranolol dose-response was studied for each strain: (1) saline solution controls (n = 18); (2) propranolol, 10 mg/kg subcutaneously (n = 18); (3) propranolol, 30 mg/kg (n = 14). Systolic blood pressure was determined by tail plethysmography before operation and on day 14, as well as by direct recording at surgery and on day 14. Rats were killed at 14 days, and aneurysm diameter was measured. RESULTS: The initial tail BP was 129 +/- 22 mm Hg in WKY animals and 158 +/- 21 mm Hg in WKHT animals (p < 0.0001). Tail BP and intraaortic systolic, diastolic, and mean blood pressure (BP) were not significantly decreased by propranolol treatment in either strain of rats. However, BP tended to rise in WKY rats, whereas it fell slightly in WKHT rats. Initial aortic size in all animals was 1.06 +/- 0.12. The final aortic size in untreated, hypertensive rats was more than twice that of untreated normotensive controls: 1: WKHT, 3.0 +/- 0.73 mm, 1: WKY, 6.9 +/- 3.5 mm (p < 0.01). After treatment with both doses of propranolol, hypertensive aneurysms were significantly smaller than the untreated WKHT group (p < 0.05) and not significantly different from aneurysms in all groups of normotensive animals: 2: WKY, 3.1 +/- 1.13 mm, 2: WKHT, 4.0 +/- 1.81 mm; 3: WKY, 4.1 +/- 0.41 mm, 3: WKHT, 2.9 +/- 1.24 mm. There was no significant difference in aortic size between the three normotensive WKY groups. CONCLUSIONS: Hypertension increases the size of aortic aneurysms in this experimental model. Propranolol significantly reduces the size of experimental AAA in hypertensive animals independently of the dose and by a mechanism that may be unrelated to simple BP reduction.

Abdominal aortic aneurysm expansion rate: effect of size and beta-adrenergic blockade.

PURPOSE: The purpose of this study was to investigate the hypothesis that abdominal aortic aneurysm (AAA) expansion may be slowed by beta-adrenergic antagonists. METHODS: One hundred twenty-one patients with infrarenal AAA were monitored with serial aortic ultrasound examinations. Eighty-three patients received no beta-blockers (group I), and 38 patients received beta-blockers (group II). Values are expressed as mean +/- SD. RESULTS: The mean follow-up was 43 +/- 29 months with 5.5 +/- 3.4 ultrasound examinations per patient. The expansion rate among all AAA was 0.38 +/- 0.44 cm/yr. Large aneurysms (> or = 5 cm) expanded significantly faster than small aneurysms (p = 0.02) in patients not treated with beta-blockers. Among patients with large AAA, those receiving beta-blockers had a significantly reduced mean expansion rate; 0.36 +/- 0.20 versus 0.68 +/- 0.64 cm/yr, (p < 0.05). Although rupture rates were lower in group I (5%) versus group II (13%), this difference was not statistically significant. Thirty-four patients in a poor-risk category with AAA were monitored greater than 5 cm in diameter. Ten of these AAA ruptured. The mean expansion rate was significantly greater in those patients with ruptured AAA versus those patients with AAA that did not rupture; 0.82 +/- 0.74 versus 0.42 +/- 0.41 cm/yr (p = 0.04). CONCLUSIONS: In patients not undergoing beta-blocker therapy, large AAA expand at a significantly greater rate than smaller AAA. Large aneurysms that rupture show more rapid expansion than those AAA that do not rupture. We have demonstrated a significantly reduced rate of expansion of large AAA in patients receiving beta-blockade.

Vascular complications of cardiac catheterization.

Peripheral vascular complications after cardiac catheterization constitute an increasing portion of traumatic vascular injuries. To determine the incidence of these complications and the sequelae of their treatment, we reviewed 7,690 catheterizations performed over a 40-month period. One hundred eleven vascular complications were detected (1%), 41 of which required surgical repair (0.5%). Pseudoaneurysm (10), arteriovenous fistula (4), thromboembolism (9), infection (5), and other bleeding complications (83) were all found. Significantly more complications occurred in patients who were older than 60 years of age or female (P < 0.0009). In addition, the likelihood of a vascular injury after coronary angioplasty was significantly higher than after angiography alone (3% versus 1%, P < 0.00001). Secondary local and systemic complications after surgical repair were more frequent compared with those injuries that were managed nonoperatively (32% versus 11%; P = 0.015). Vascular complications continue to be a significant problem after cardiac catheterization, especially when coronary angioplasty is performed. The sequelae of surgical repair are significant, adding to their morbidity. Periodic review of these complications may identify factors that might be modified to reduce complications.

Morphology predicts rapid growth of small abdominal aortic aneurysms.

This study evaluated CT scans of small abdominal aortic aneurysms (AAAs) (< 5 cm) to assess anatomic features associated with rapid expansion. Serial CT scans obtained at least 10 months apart (mean 15 months) from patients with small AAAs were reviewed. Each cross-sectional image of the AAAs was analyzed using a computer-assisted design program. The circumference of the AAA in each CT image was divided into eight equal arcs, from which the apparent radius of curvature (Rc) for each segment was calculated. Flattening of the wall curvature results in an increased segmental Rc. The CT scans of nine patients with expanding AAAs (expansion > or = 0.5 cm/yr) were compared to those of 10 patients with stable AAAs (expansion < or = 0.2 cm/yr). To adjust for differences in AAA size, the Rc for each segment was normalized by dividing each individual Rc by the average of the eight Rcs (RcAvg) calculated for that cross-sectional CT image. Analysis of variance showed that the left posterolateral segments in expanding AAAs had larger Rc/RcAvg ratios than those segments in stable AAAs (1.14 +/- 0.19 vs. 0.80 +/- 0.09, p < 0.02). Laplace's law indicates that the left posterolateral segment in AAAs that grow more rapidly is subjected to greater wall tension. Flattening in the curvature of the left posterolateral wall segment was significantly associated with an increased rate of expansion in small AAAs. This finding, readily derived from standard CT scan images, may predict which small AAAs are more prone to rapid expansion.

Hypertension accelerates the growth of experimental aortic aneurysms.

Hypertension has long been suspected to increase the growth rate of abdominal aortic aneurysms (AAA), but there is little experimental evidence to support this hypothesis. Using an established model, aneurysms were induced in normotensive Wistar-Kyoto (WKY) rats and in a unique strain of genetically hypertensive Wistar-Kyoto (WKHT) rats by perfusing an isolated segment of the infrarenal aorta with elastase (n = 14, each group). Aortic diameter was measured with a micrometer and systolic blood pressure (sBP) determined by tail plethysmography. Rats were killed at 7 or 14 days, aneurysm diameter was measured, and aneurysms were examined histologically. Systolic blood pressure was significantly higher in WKHT rats (164 +/- 15 mm Hg) compared to WKY animals (119 +/- 7 mm Hg, P < 0.001). Initial aortic size was 1.10 +/- 0.02 mm in the two groups. Aneurysms in the hypertensive animals were significantly larger at Day 7 (WKY, 2.31 +/- 0.09 mm; WKHT, 2.54 +/- 0.22 mm; P = 0.02) and Day 14 (WKY, 2.36 +/- 0.25; WKHT, 3.45 +/- 0.89; P = 0.001). Overall, the mean AAA growth rate of the WKYHT group was nearly twice that of the WKY group: 0.13 +/- 0.09 mm/day vs 0.07 +/- 0.03 mm/day, (P = 0.004). Growth rates were also positively correlated with sBP (r = 0.82, P < 0.0001). Both groups showed elastic lamellar disruption and inflammatory cell infiltration within the wall of the aorta. As demonstrated in this experimental model, hypertension does indeed increase the rate of growth of AAA.

Practical evaluation of trauma deaths.

The TRISS method of auditing trauma deaths necessitates audit of patients with minor injuries who die of their underlying medical problems. Using an anatomic definition of injury as a criterion for audit, as suggested by Wesson et al. at the Hospital for Sick Children in Toronto, excludes patients with minor injuries but necessitates audit of patients who expired due to systems problems rather than in-hospital patient care. We propose combining the TRISS and Toronto methods in order to identify the deaths truly appropriate for detailed review of hospital care. Fifty-four trauma deaths over a 22-month period were audited and categorized as frankly preventable, potentially salvageable, or nonpreventable. Considering only in-hospital care, the deaths designated as potentially salvageable by audit were likely to be identified by both TRISS and Toronto, while deaths targeted by only one system were more likely to be nonpreventable by audit. The predictive value of this combination of methods (84.6%) was better than Toronto (52.4%) or TRISS (54.5%) using audit results as the standard for comparison. This simple computerized method may serve as a practical and inexpensive method of targeting deaths for in-depth review.

Zero-time prehospital i.v.

Advances in prehospital stabilization and resuscitation of traumatized victims continue to have an impact on morbidity and mortality. Certain aspects of Advanced Trauma Life Support still remain controversial. Recent reports have questioned the usefulness of IV's started in the prehospital phase both because of delay in transport and because of the actual or theoretical lack of adequate volume infusion during transport. If IV lines can be started while an accident victim is en route to the hospital with no delay in transport, then much of the argument against prehospital IV's becomes irrelevant. From October 1985 through November 1986 we prospectively studied IV access attempts in 350 consecutive patients. Overall IV's started at the scene were 77% successful (n = 70) and en route 81% (n = 213) of attempts were successful. Of those with BP less than 100 mm Hg, there were 66% successful on-scene attempts and 72% successful en-route attempts. Protocols for IV administration in non-trapped patients should initiate IV access only en route to the hospital while the ambulance is moving. Even if delay at the scene is minimal, it is not possible to justify any delay, since IV's can be successfully instituted en route.

A prospective randomized trial of the Lazarus-Nelson vs. the standard peritoneal dialysis catheter for peritoneal lavage in blunt abdominal trauma.

One hundred consecutive injured patients with blunt abdominal trauma requiring peritoneal lavage were prospectively randomized to placement of lavage catheters with an open or percutaneous technique. The Lazarus-Nelson catheter, placed by Seldinger wire technique, was compared to a standard dialysis catheter, placed by direct visualization and incision of the peritoneum. Placement of the catheter was consistently faster using the percutaneous method; no difference was noted in time of lavage, volume recovered, or complications. When not contraindicated, the percutaneous technique was widely preferred by study participants.

Renal failure after embolization of a prosthetic mitral valve disc and review of systemic disc embolization.

Embolization of discs from various prosthetic mitral valves produces fulminant cardiac failure with possible survival after emergent mitral valve prosthetic replacement. The embolized discs lodge in the aorta at various levels parallel to the blood stream and have not occluded distal flow. Some embolized discs have been left in the aorta for as long as 12 years. An embolized disc left in the abdominal aorta produced renal artery occlusion 5 years after embolization in the reported case. A previous case produced mesenteric ischemia after 1 month. Localization of embolized discs has at times been difficult with success and failure by plain x-ray films, ultrasound, angiography, and CT scans in some cases. Since embolized discs have not produced acute problems with ischemia, delay of retrieval after emergent mitral valve replacement does not seen detrimental. Late complications may occur as with the present case and removal of asymptomatic embolized discs seems advisable and prudent.

Carotid body tumors.

A review of seven carotid body tumors less than 5 cm in diameter confirms the thesis of other recent reports that such tumors can be resected with minimal morbidity. In two of our cases, initial exploration and biopsy were performed not suspecting the nature of the neck mass; in one of these, hypoglossal and facial nerve deficits resulted. Angiography was diagnostic in six of our seven cases and should be used to establish the diagnosis preoperatively in any neck mass of doubtful origin where carotid body tumor is a part of the differential diagnosis.

Review of care of fatally injured patients in a rural state: 5-year followup.

Of fatally injured patients with non-CNS injuries reaching the ER alive in an entire state from 1975-1979, 22% were judged to have potentially survivable injuries. A previous study from 1969-1974 in the same state of fatally injured abdominal injury patients showed 26% potential survivors. Errors in initial volume replacement, airway-respiratory control, and in the recognition of surgical urgency stand out in the present series. Review of these cases suggests that stabilization and resuscitation are necessary before transfer and that bypass to a regional trauma center would not have been likely to be effective in such a rural state.