Popliteal Artery Occlusion Secondary to Cystic Adventitial Disease: A Rare Etiology of Lower Extremity Ischemia in a Marathon Runner

A 44-year-old marathon runner was referred with a 2-week history of the sudden onset of severe left calf claudication. Angiography showed a 3- to 4-centimeter focal nearocclusion of the left midpopliteal artery. Magnetic resonance imaging showed a cystic structure in the left popliteal artery wall. A left popliteal artery exploration revealed popliteal artery occlusion secondary to cystic adventitial disease. Excision of the cyst resulted in restoration of pedal pulses. This rare disease of uncertain etiology should be suspected in young adults presenting with ischemia. Various noninvasive techniques in conjunction with arteriography result in reliably diagnosing cystic adventitial disease. Excision of the cyst usually provides adequate treatment. Resection of the diseased arterial segment with autogenous bypass may be required.

Patient Outcomes Following Placement of a Second Inferior Vena Cava Filter

Inferior vena cava (IVC) interruption is being performed with increasing frequency. Indications for this procedure have expanded since the introduction of percutaneous placement techniques. Indications for placement of a second IVC filter are less well defined. It has been reported that a second filter can be placed safely. The purpose of this study was to investigate the intermediate and long-term follow-up of these patients.

Five patients underwent placement of a second IVC filter at one institution from 1992 to 1996. During the same period a total of 439 patients underwent IVC filter placement. The five patients, ranging in age from 46 to 67 years, included three men and two women. The indication for the second filter placement was a confirmed or strongly suspected recurrent pulmonary embolus (PE), with thrombus in and above the previously placed IVC interruption device in all patients. Three of the five patients suffered from poorly controlled malignancies. One patient had an ependymoma of the spinal cord that was completely excised. The fifth patient had a documented hypercoagulable state: factor V resistance to activated protein C. The mean time between placement of the first and second filters was 31 weeks (range: 1-65 weeks). Mean follow-up was 94 weeks (range: 0-252 weeks). One patient died within 24 hours of filter placement from profound hypoxemia from a preexistent PE. No fatal PE occurred in any of the four remaining patients. Two patients in this study, following placement of a second IVC filter, had documented pulmonary emboli that were nonfatal. Two patients died as a result of their underlying malignancies.

While placement of a second IVC interruption device is an infrequently performed procedure, it appears to be efficacious in preventing death from pulmonary emboli in this extremely high-risk group of patients.

Duplex Ultrasonography to Predict Internal Carotid Artery Stenoses Exceeding 50% and 70% as Defined by NASCET: The Need for Multiple Criteria

Carotid duplex scanning is being used more frequently as the sole preoperative diagnostic imaging modality for patients considered candidates for carotid endarterectomy. The North American Symptomatic Carotid Endarterectomy Trial (NASCET) has demonstrated the benefit of surgical treatment in patients with carotid stenoses exceeding 70%. The purpose of this study was to determine duplex criteria that accurately predict carotid stenoses exceeding 50% and 70% as defined by NASCET arteriographic criteria. One hundred forty-one patients (264 carotid arteries) considered surgical candidates were prospectively studied over a 2-year period by use of both duplex scanning and digital subtraction cerebral arteriography. Carotid artery stenosis was determined by a single radiologist using NASCET arteriographic criteria. Peak systolic velocity (PSV) and enddiastolic velocity (EDV) were measured in the internal carotid (ICA) and common carotid (CCA) arteries by use of duplex scanning. ICA/CCA velocity ratios were calculated for PSV and EDV. Sensitivity, specificity, positive and negative predictive values, and accuracy were calculated. PSVICA/CCA provided the highest sensitivity, and EDVICA the highest specificity in this study. Arteriographic stenoses exceeding 50% and 70% were reliably predicted with use of these duplex criteria. It is concluded that duplex criteria can predict carotid stenoses exceeding 50% and 70% as defined by NASCET arteriographic criteria. These criteria should be independently validated by other vascular laboratories.

The Use of Preoperative Noninvasive Vascular Studies for the Evaluation of Radial Artery Conduits for Coronary Artery Bypass Grafting

Background: The increased use of the radial artery for coronary artery bypass conduits has heightened the awareness of potential resultant hand ischemia. The Allen test and subsequent modifications have been used to evaluate the patency of the superficial palmar arch (SPA). The purpose of this study was to determine if changes in blood flow patterns of the SPA assessed by the modified Allen test parallel changes in blood pressures of the first and second digits following radial artery occlusion.

Methods: Continuous-wave Doppler ultrasound and photoplethysmography (PPG) were used to evaluate blood flow in the SPA and first and second digits, respectively, before and after manual occlusion of the radial artery in 60 extremities. A second continuouswave Doppler probe was used to ensure complete occlusion of the radial artery. Digit skin temperature was controlled between 36° and 37.5°0. A reduction of >20 mmHg in blood pressure was arbitrarily chosen to reflect a clinically significant change in digit arterial pressure.

Results: Six of the 60 extremities (10%) studied showed a decrease in the audible Doppler signal over the SPA following radial artery occlusion. Reduction in digit arterial pressure following radial artery occlusion occurred in 13 of 60 extremities (21.7%). Digit arterial pressure reductions ranged from 20 to 58 mmHg (mean ±SD, 35.2 ±12.8 mmHg), demonstrating a 40% decrease in digital pressure. Changes in SPA flow did not parallel digital pressure changes following occlusion of the radial artery.

Conclusion: Continuous-wave Doppler ultrasound of the SPA following radial artery compression alone does not accurately predict digit ischemia. Digit arterial pressure measurement of the first and second digits of upper extremities offers a relatively simple and objective method for evaluation of potential ischemic complications following radial artery harvest. This finding is important because many physicians only use a modified Allen test with radial artery compression to assess potential digit ischemia.

Construct domain analysis of patient health-related quality of life: physical and mental trajectory profiles following open versus endovascular repair of abdominal aortic aneurysm

Purpose

Many clinical trials comparing the outcomes of open surgical repair (OSR) versus endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAAs) have been conducted, with varying results. Surprisingly, few outcomes studies have closely examined perceived physical and mental health-related quality of life (HRQOL) factors through a validated survey tool. The purpose of this prospective observational study was to describe the trajectory of HRQOL measures, from baseline to 1 year after surgery, in patients undergoing OSR or EVAR for AAA, and to explore for differences in physical and mental composite scores and their construct domains (subscales) using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36^®) tool.

Patients and methods

Over an 18-month period, a small sample of patients undergoing elective AAA repair in a community hospital setting were prospectively enrolled. Fifteen patients undergoing OSR and twenty patients undergoing EVAR were studied. Physical and mental HRQOL parameters were assessed using the SF-36.

Results

No significant differences in demographic and clinical variables were found between the OSR and EVAR groups. In the multivariable linear models with repeated measures, both groups showed a significant decline in physical health composite scores 30 days after the surgical procedure (P < 0.01). However, although the OSR group showed a statistically significant decline in three of the four physical health domains, the EVAR group declined in only one physical health domain. Only the OSR group showed a significant decline in three of the four mental health domains at 30 days; however, the decline of these domains was not reflected in the group’s mental health composite scores. By 90 days after surgery, both groups were not significantly different from their baseline in physical or mental health composite scores, or in any of their respective physical health domains.

Conclusion

In this small sample of patients undergoing AAA repair, EVAR resulted in less physical and emotional decline than OSR in the early postoperative period. However, patients in both groups may return to near baseline status at 90 days.

Outcomes of carotid endarterectomy under general and regional anesthesia from the American College of Surgeons' National Surgical Quality Improvement Program

OBJECTIVE

Despite multiple studies over more than 3 decades, there still is no consensus about the influence of anesthesia type on postoperative outcomes following carotid endarterectomy (CEA). The objective of this study was to investigate whether anesthesia type, either general anesthesia (GA) or regional anesthesia (RA), independently contributes to the risk of postoperative cardiovascular complications or death using the American College of Surgeons' National Surgical Quality Improvement Program (ACS NSQIP) database.

METHODS

Retrospective analysis of elective cases of CEA from 2005 through 2009 was performed. A propensity score model using 45 covariates, including demographic factors, comorbidities, stroke history, measures of general health, and laboratory values, was used to adjust for bias and to determine the independent influence of anesthesia type on postoperative stroke, myocardial infarction (MI), and death.

RESULTS

Of 26,070 cases listed in the ACS NSQIP database, GA and RA were used in 22,054 (84.6%) and 4016 (15.4%) cases, respectively. Postoperative stroke, MI, and death occurred in 360 (1.63%), 133 (0.6%), and 154 (0.70%) patients of the GA group, respectively, and in 58 (1.44%), 11 (0.27%), and 27 (0.67%) patients of the RA group, respectively. Stratification by propensity score quintile and adjustment for covariates demonstrated GA to be a significant risk factor for postoperative MI with an adjusted odds ratio (OR) and confidence interval (CI) of 2.18 (95% CI, 1.17-4.04), P = .01 in the entire study population. The OR for MI was 5.41 (95% CI, 1.32-22.16; P = .019) in the subgroup of patients with preoperative neurologic symptoms, and 1.44 (95% CI, 0.71-2.90; P = .31) in the subgroup of patients without preoperative neurologic symptoms.

CONCLUSIONS

This analysis of a large, prospectively collected and validated multicenter database indicates that GA for CEA is an independent risk factor for postoperative MI, particularly in patients with preoperative neurologic symptoms.

Operative therapy of renovascular hypertension

Three hundred and thirteen patients exhibiting renal artery occlusive disease underwent operation for renovascular hypertension. These included 34 paediatric and 144 adult patients with fibrodysplastic disease. Atherosclerotic lesions affected an additional 64 patients without and 71 patients with clinically overt extrarenal arteriosclerotic cardiovascular disease. Ischaemic kidney renin hypersecretion (renal: systemic renin index &gt; 0·48), associated with suppressed contralateral kidney renin secretion (renal: systemic renin index approaching 0·0), predicted curability most reliably. Four hundred and fifteen operations were performed of which 356 were primary and 59 were secondary procedures. Aortorenal bypass using autogenous vein (227 cases) or prosthetic grafts (62 cases) was the most common primary operation. Nephrectomy was the initial therapy in 17 cases. Six operative deaths occurred in patients manifesting overt extrarenal arteriosclerotic disease. No operative mortality was encountered among the remaining 242 patients. Improvement was seen following operation in 97 per cent of paediatric patients and 94 per cent of adults with fibrodysplastic disease, in 91 per cent of patients with focal renal arteriosclerosis and in 72 per cent of those exhibiting overt extrarenal arteriosclerosis.

Resident research training conducted in a community hospital general surgery residency program

PURPOSE

Research is educationally important for surgical residents. However, little information exists regarding effective methods for teaching residents scientific methodology in a community hospital. This effort describes an effective program conducted in a community hospital for enhancing scientific opportunities of surgical residents.

METHODS

A strong infrastructure that supports research is necessary. Dedicated nonsalaried teaching faculty serve as mentors and co-investigators. Opportunities to engage in basic research are made available in off-campus basic science laboratories.

RESULTS

Research productivity has been prolific, as demonstrated by numerous publications. Residents interested in sub-speciality training have been able to conduct research that has made them competitive for fellowships and a wider range of practice choices.

CONCLUSION

Rigorous research can be effectively taught in a community hospital, provided adequate educational and funding support is provided and faculty actively mentor residents. Having research capabilities provides added incentive for better-qualified medical students to apply to a surgical residency position in a community hospital. Research productivity also enhances the ability to better recruit new faculty.

Can ulnar artery velocity changes be used as a preoperative screening tool for radial artery grafting in coronary artery bypass?

Radial artery harvesting for coronary revascularization may result in digit ischemia if collateral circulation is inadequate. The purpose of this study was to compare changes in ulnar artery flow velocity during radial artery compression (RAC) with changes in first- and second-digit pressures during RAC, a previously validated predictor of digital ischemia. Photoplethysmography was used to measure first- and second-digit arterial pressures before and during RAC on 80 extremities. Color flow duplex imaging was used to measure distal ulnar artery peak systolic velocity before and during RAC. Seventy-eight of eighty extremities had a slight increase in ulnar artery velocity with RAC. There was no correlation between ulnar artery velocity changes and digit pressure changes. Measurement of ulnar artery velocity during RAC is not a useful predictor of digit pressure changes. Measurement of segmental upper extremity pressures with first- and second-digit pressure measurement during radial artery compression should remain the preferred preoperative screening tool for radial artery harvest prior to CABG.

Simultaneous bilateral upper extremity venous thrombosis in a factor V Leiden heterozygote: a case report and review

Primary upper extremity deep venous thrombosis (DVT), or effort thrombosis, typically occurs in young, healthy individuals with a history of repetitive upper extremity movement while secondary upper extremity DVT is associated with a number of predisposing factors. The role of factors such as hypercoagulability in the development of effort thrombosis is less well described. This report describes a previously healthy 21-year-old man who presented with simultaneous bilateral upper extremity DVT after hours of pushing and lifting a heavy wheelbarrow. Treatment included thrombolytic therapy followed by delayed venolysis and vein patch angioplasty. Hypercoagulable screening revealed factor V Leiden heterozygous characteristics.

Upper extremity venous gangrene following coronary artery bypass. A case report and review of the literature

Acute symptomatic upper extremity deep vein thrombosis (DVT) are estimated to account for only 2-4% of all deep vein thrombosis. Upper extremity DVT leading to phlegmasia cerulea dolens (PCD) occurs in an estimated 2-5% of these cases. Progression of PCD to venous gangrene is extremely rare with only 16 previously reported cases in the literature. Only 7 of the cited cases document significant tissue loss. This report describes a 61-year-old male who developed upper extremity DVT complicated by PCD which led to venous gangrene and limb loss.

Noninvasive evaluation of hand circulation before radial artery harvest for coronary artery bypass grafting

OBJECTIVE

Radial artery harvesting for coronary artery bypass may lead to digit ischemia if collateral hand circulation is inadequate. The modified Allen's test is the most common preoperative screening test used. Unfortunately, this test has high false-positive and false-negative rates. The purpose of this study was to compare the results of a modified Allen's test with digit pressure change during radial artery compression for assessing collateral circulation before radial artery harvest.

METHODS

One hundred twenty-nine consecutive patients were studied before coronary artery bypass operations. A modified Allen's test was performed with Doppler ultrasound to assess blood flow in the superficial palmar arch before and during radial artery compression. A decreased audible Doppler signal after radial artery compression was considered a positive modified Allen's test. First and second digit pressures were measured before and during radial artery compression. A decrease in digit pressure of 40 mm Hg or more (digit DeltaP) with radial artery compression was considered positive.

RESULTS

Seven of 14 dominant extremities (50%) and 8 of the 16 nondominant extremities (50%) with a positive modified Allen's test had a digit DeltaP of less than 40 mm Hg (false positive). Sixteen of 115 dominant extremities (14%) and 5 of 112 nondominant extremities (4%) with a negative Allen's test had a digit DeltaP of 40 mm Hg or more with radial artery compression (false negative).

CONCLUSION

Use of the modified Allen's test for screening before radial artery harvest may unnecessarily exclude some patients from use of this conduit and may also place a number of patients at risk for digit ischemia from such harvest. Direct digit pressure measurement is a simple, objective method that may more precisely select patients for radial artery harvest. Additional studies are needed to define objective digital pressure criteria that will accurately predict patients at risk for hand ischemia after radial harvest.

Incidence and pathophysiologic significance of infected carotid artery plaque

It is unknown whether an association exists between infectious microorganisms and atherosclerosis. Eighty consecutive patients undergoing carotid endarterectomy were studied to detect for bacterial or virus infections in removed carotid atherosclerotic plaques. Twenty-one patients (25%) were found to have positive cultures for bacteria of the carotid plaques. Three patients (4%) did not have bacterial contamination of controlled cultures of the skin. Of these three patients, two grew diptheroids and one grew staphylococcus. The control cultures of the skin demonstrated that 25 patients (31%) grew diphtheroids and 29 (36%) grew staphylococcus. Five patients grew both organisms. There was no evidence of colonization within the atheromatous plaque material in histologic studies of the three patients that had positive cultures of their plaque. All viral cultures were negative. The positive carotid cultures found were most likely due to contamination from the skin. This study demonstrates the unlikelihood of bacterial or virus infections as either an etiologic or a pathogenetic factor in carotid artery atherogenesis.

The effect of protamine sulfate on platelet function

The adverse effects of protamine sulfate, used to neutralize the anticoagulant action of heparin, include systemic hypotension, pulmonary artery hypertension, thrombocytopenia and leukopenia. For further evaluation of protamine's mechanism of action, a three-part investigation was performed. In part I platelet-rich plasma (PRP) was prepared from canine blood samples (n = 6) taken before and 2 minutes after injection of protamine. In part II human PRP (n = 5) was preincubated with protamine or distilled water. Adenosine diphosphate-induced aggregation of protamine-treated platelets was unchanged, but thrombin-induced aggregation was inhibited in both canine and human preparations (p less than 0.05). In part III thrombocytopenia was produced in splenectomized dogs (n = 5), using microporous filters, to 4.5-8.4% of the initial platelet count. Protamine reversal of the heparinization caused hypotension (maximally -29 mmHg 90 s after protamine), but not pulmonary arterial hypertension. Leukopenia developed before additional thrombocytopenia appeared. Protamine-platelet interaction inhibits thrombin-induced platelet aggregation. Platelets may play an important role in the pulmonary pressure rise during protamine reversal, but do not mediate the systemic hypotension.

Protamine reversal of anticoagulation achieved with a low molecular weight heparin. The effects on eicosanoids, clotting and complement factors

Hemodynamic and hematologic effects of protamine reversal of low molecular weight heparin (LMWH) anticoagulation with and without protamine pretreatment, as well as reversal of anticoagulation with unfractionated standard heparin (SH), were studied in canine subjects. Protamine reversal caused less severe thrombocytopenia in the two LMWH groups compared to SH animals, while neutropenia occurred equally in all groups. Cl-esterase inhibitor levels were minimally increased, whereas C3 levels and leucotriene levels were unaltered. TxB2 and 6-keto-PGF1 alpha increased during protamine reversal of LMWH anticoagulation. TCT and APTT were affected less with LMWH than SH anticoagulation. Anti-Xa levels increased with anticoagulation in all animals, but protamine did not reverse the elevated anti-Xa levels in LMWH anticoagulated dogs to the same degree as occurred with SH anticoagulation. TCT, APTT and bleeding times were normalized by protamine in all animals. Protamine reversal of LMWH anticoagulation with or without protamine pretreatment did not reveal any clear differences in eicosanoids or complement factors compared to SH anticoagulation, although differences in anti-Xa activity clearly separated these two heparins.

Treatment of established prosthetic vascular graft infection with antibiotics preferentially concentrated in leukocytes

The efficacy of treating established vascular graft infections with rifampin and clindamycin (preferentially concentrated in leukocytes) and cefazolin (not concentrated in leukocytes) was studied in a canine model. Infrarenal aortic, 6 mm by 6 cm knitted Dacron double velour grafts were implanted and infected with 10(8) colony-forming units (CFU) of coagulase-positive Staphyloccus aureus organisms injected intravenously immediately after graft placement. Antibiotic therapy was instituted at 3 months postimplantation. Three groups were studied: (I) untreated controls (n = 3); (II) therapy with intravenous cefazolin 15 mg/kg/8 hr for 28 days (n = 7); and (III) combined therapy with intravenous rifampin 13 mg/kg/24 hr and intravenous clindamycin 13 mg/kg/8 hr for 28 days (n = 7). Grafts were removed for quantitative bacteriologic studies after the 28-day course of therapy. Two group I control grafts remained patent with 6.4 X 10(6) and 8.1 X 10(3) CFU S. aureus/gm of graft. The third control graft was thrombosed. Two group II animals demonstrated 1.6 X 10(7) and 2.3 X 10(5) CFU S. aureus organisms/gram of graft, respectively; the remaining five group II grafts were free of organisms. All group III grafts were sterile--a significant difference (p less than 0.05) from group I grafts. In this experimental model, established prosthetic graft infections were eradicated by intensive treatment with antibiotics preferentially concentrated in leukocytes.

Haemodynamic and haematologic alterations with protamine reversal of anticoagulation: comparison of standard heparin and a low molecular weight heparin fragment

Reversal of anticoagulation with protamine sulfate causes many adverse haemodynamic and haematologic effects which could be due to differences in the mechanism of action of standard and low molecular weight heparin. Three groups of dogs were investigated: one group received normal saline pretreatment followed by heparinisation with standard heparin 150 IU/kg followed by protamine sulfate reversal 1.5 mg/kg after aortic interposition grafting: the second group were given normal saline pretreatment followed by heparinisation with low molecular weight heparin 150 U antiXa/kg and after grafting protamine sulfate reversal 1.5 mg/kg. The third group were given protamine sulfate pretreatment 2.25 mg/kg followed by low molecular weight heparin 150 U antiXa/kg and later protamine sulfate reversal 1.5 mg/kg after grafting. The same haemodynamic changes were seen regardless of the type of heparin or pretreatment with protamine given along with low molecular weight heparin. There was a suggestion that regular heparin cause a more pronounced increase in pulmonary artery pressure and a decrease in heart rate. On the other hand the systemic hypotension and reduction of cardiac output seemed more pronounced in the low molecular weight heparin group. Platelet count decreased less in the low molecular weight heparin group, but white blood cell count was equally reduced. Pretreatment with protamine did not abolish the adverse effects of protamine when reversing anticoagulation achieved with low molecular weight heparin, a finding not shared with standard heparin-protamine interactions.

Presentation and perioperative management of arterioportal fistulas

Arterioportal fistulas (APFs) are usually traumatic in origin and may result in portal hypertension and its complications. Over six years, six patients (aged 20 to 59 years) presented with APFs. Two APFs developed after percutaneous liver biopsy, but only one was complicated (hemobilia). Neither patient was treated operatively. Four APFs occurred two days to three years after gunshot wounds. Three patients presented with gastrointestinal tract hemorrhage. All patients had abdominal bruits. Two patients underwent primary repair. One patient underwent APF resection and replacement of the superior mesenteric artery with autogenous vein. Another patient underwent APF and bowel resection. Three patients survived. One patient died of liver failure. The development of an abdominal bruit in a patient with penetrating abdominal trauma suggests APF and should prompt angiography. Elective repair is recommended before complications of portal hypertension develop.

Effects of continuous intravenous infusions of nitroglycerin on canine systemic and hind limb microcirculatory hemodynamics

Systemic and hind limb hemodynamics were assessed in anesthetized dogs during continuous 30-minute intravenous infusions of nitroglycerin at 1, 5, 10, and 25 micrograms/kg/min. Nitroglycerin at 1 microgram/kg/min redistributed hind limb blood flow; hind limb arteriovenous shunting increased from 5.6% +/- 4.0% to 17.8% +/- 7.4% after 30 minutes (p less than 0.01); absolute hind limb shunt flow increased from 12 +/- 10 ml/min to 31 +/- 26 ml/min at 10 minutes (p less than 0.01); whereas hind limb nutrient blood flow decreased from 184 +/- 81 ml/min to 150 +/- 55 ml/min and 132 +/- 32 ml/min, respectively, at 10 and 30 minutes (p less than 0.05). Such hind limb blood flow redistribution was absent during infusion of all other nitroglycerin dosages. Total catecholamines increased at 30 minutes during both 1 and 10 micrograms/kg/min nitroglycerin infusions (p less than 0.05) with perhaps a slightly greater catecholamine response to 10 micrograms/kg/min after 30 minutes (0.05 less than p less than 0.10). The renin-angiotensin response at 3 minutes differed between nitroglycerin infusions of 1 and 10 micrograms/kg/min with an initial significant reduction from baseline in plasma renin activity at the lower dose compared with a significant increase from baseline in plasma activity at the higher dose. Nitroglycerin did not increase femoral artery flow or cardiac output and did not lower total peripheral vascular resistance at any dose studied. Despite this, arterial pressure and cardiac work were reduced at all nitroglycerin doses tested. Massive volume loading prevented the anticipated blood pressure reduction and blunted the expected cardiac work reduction during nitroglycerin infusions of 10 micrograms/kg/min. This study demonstrates that nitroglycerin is not a potent peripheral arteriolar vasodilator, 1 microgram/kg/min nitroglycerin infusions increase hind limb arteriovenous shunting and decrease hind limb nutrient blood flow, and myocardial work and arterial pressure reductions during nitroglycerin infusions appear to be caused by mechanisms other than generalized peripheral arterial dilation.

Prostacyclin treatment of ischemic ulcers and rest pain in unreconstructible peripheral arterial occlusive disease

The efficacy of prostacyclin (PGI2) treatment was assessed in 26 patients with surgically unreconstructible atherosclerotic arterial occlusive disease of the lower extremity manifested by nonhealing ulcers and rest pain. Patients were randomized to receive a 72-hour intravenous infusion of PGI2 (6 ng/kg/min, n = 13) or placebo (n = 13). Ulcer size was measured by photographic planimetry, and rest pain was graded by blinded objective scoring at monthly intervals for 6 months. Ulcer size increased 64% in PGI2-treated patients and 22% in placebo-treated patients by 1 month after infusion. Rest pain decreased slightly in both PGI2 and placebo groups. At the conclusion of the study, 54% of placebo-treated patients and 31% of PGI2-treated patients had a positive treatment response, indicated by at least a 20% decrease in ulcer size and a 33% decrease in rest pain. PGI2 infusion did not improve the high-placebo response rate seen in these patients with severely ischemic extremities. These results emphasize the importance of placebo-controlled studies, even in patients with unreconstructible arterial disease.

Attenuation of hemodynamic and hematologic effects of heparin-protamine sulfate interaction after aortic reconstruction in a canine model

This investigation documented the effect of protamine sulfate pretreatment on the adverse hemodynamic and hematologic sequela of rapid intravenous protamine administration in heparinized dogs having undergone prior implantation of aortic prostheses. Fourteen dogs underwent infrarenal aortic replacement with 6 mm inner diameter by 7 cm knitted Dacron double-velour grafts. Carotid arterial, central venous, and pulmonary arterial catheters were placed for continuous hemodynamic monitoring. All dogs were adequately anticoagulated with heparin (150 IU/kg) and reversed with protamine (1.5 mg/kg/10 sec) after graft insertion. Pretreatment regimens studied included normal saline (n4), protamine 0.75 mg/kg (n5), and protamine 2.25 mg/kg in three divided doses of 0.75 mg/kg each (n5). All pretreatment agents were administered 3 minutes before heparinization. Blood pressure (BP), heart rate (HR), pulmonary artery pressure (PAP) and cardiac output (CO) were measured. Hematologic assessments included platelet count (PC), leukocyte count, thrombin clotting time, and total hemolytic complement. Significant salutory effects were associated with protamine pretreatment regarding BP, HR, PAP, CO, and PC. It is concluded that adverse hemodynamic effects of protamine reversal are blocked and certain hematologic effects are reduced with protamine pretreatment before heparinization and its reversal in this canine experimental model.

Protamine pretreatment attenuation of hemodynamic and hematologic effects of heparin-protamine interaction. A prospective randomized study in human beings undergoing aortic reconstructive surgery

Hemodynamic and hematologic responses to protamine sulfate reversal of heparin's anticoagulant effects were studied in 15 consecutive randomized patients undergoing aortic reconstructive surgery. In a double-blinded manner, patients were pretreated with either normal saline solution (n = 8) or protamine (0.75 mg/kg/3 min, n = 7) 5 minutes before heparinization (150 IU/kg). After aortic grafts were placed, protamine (1.5 mg/kg/3 min) was administered intravenously to reverse the heparin. Arterial blood pressure, heart rate, pulmonary artery and capillary wedge pressure, central venous pressure, and cardiac output were monitored, as were platelet count, white blood cell count, activated clotting time, total hemolytic complement levels, and C3a levels. Calculated parameters included systemic vascular resistance and pulmonary vascular resistance. Pretreatment with protamine compared with saline solution prevented the hypotension (+6 vs. -16 mm Hg, p less than 0.05) and declining pulmonary artery pressure (+1 vs. -7 mm Hg, p less than 0.01) observed with protamine reversal of heparin. Significant differences between the two groups in central venous pressure and pulmonary vascular resistance were of less clinical relevance. Protamine pretreatment lessened the thrombocytopenia found during reversal compared with saline-pretreated patients although the difference was not statistically significant. Minimal hypotension occurring after protamine pretreatment alone was not accompanied by hemodynamic or hematologic changes, other than decreased heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Nuclide imaging of vascular graft-platelet interactions: comparison of indium excess and technetium subtraction techniques

Indium-111-labeled platelet adherence to ePTFE thoracoabdominal vascular prostheses in a canine model (n = 10) was quantitated by (1) an indium-111 excess technique, contrasting graft radioactivity to that in a reference region, and (2) a technetium-99m subtraction technique, with radioactivity of circulating platelets eliminated by discounting background blood activity. Variation in graft thrombogenicity was provided by seeding six prostheses with enzymatically derived autologous endothelial cells, and implanting four prostheses without seeding. Grafts were imaged at 1, 4, and 6 weeks postimplantation, with platelet labeling using indium-111-oxine and red blood cell labeling using technetium-99m. At 7 weeks grafts were excised and gamma activity was measured in proximal, middle, and distal segments. Luminal generation of TxB2 and 6-keto-PGF1 alpha from midportions of grafts was assayed. Indium-111 excess ratios at 6 weeks correlated with actual gamma activity of excised grafts (proximal r = 0.80, P less than 0.01; middle r = 0.73, P less than 0.05; distal r = 0.48, ns) but such a correlation did not exist for the technetium-99m subtraction technique (r = -0.05, -0.25, and 0.16, in the three segments, respectively, all ns). The ratio of graft to aortic TxB2 production revealed a positive correlation with graft gamma activity (r = 0.87, P less than 0.01), and the ratio of graft 6-keto-PGF1 alpha to TxB2 production also correlated with gamma counts (r = -0.64, P = 0.05). In this experimental setting technetium-99m subtraction analysis was an imprecise method of detecting graft platelet accumulation, whereas indium-111 excess ratios proved to be a more accurate method of quantitating vascular prosthetic thrombogenicity.

Comparative hemodynamic effects of selective superior mesenteric arterial and peripheral intravenous glucagon infusions

This experiment was designed to determine whether any hemodynamic benefits attend administration of equal pharmacologic doses of glucagon (1 micrograms/kg/m) by continuous intravenous infusion (Group I, n = 6) versus selective intraarterial infusion (Group II, n = 6) via the superior mesenteric artery (SMA) in dogs. Cardiac output, heart rate, mean arterial pressure, total peripheral resistance, pulmonary vascular resistance, superior mesenteric artery flow (SMAQ), SMA vascular resistance, and portal venous pressure were measured at baseline (BL) and at 5, 15, 30, and 45 min during glucagon infusion. SMAQ virtually doubled at 5 min from a baseline of 570 +/- 60 ml/min to 1158 +/- 146 ml/min in Group I (P less than 0.001), and from a baseline of 527 +/- 171 to 1018 +/- 331 ml/min in Group II (P less than 0.002). SMAQ was significantly higher in Group I at 30 and 45 min compared to Group II (P less than 0.03) despite similar peripheral plasma glucagon levels. SMA vascular resistance was significantly lowered in both groups, with a greater reduction occurring during intravenous glucagon administration at 45 min (P less than 0.05). Changes in systemic hemodynamic parameters, as well as glucagon and glucose levels were not statistically different between Groups I and II at any time period. Glucagon is a potent mesenteric vasodilator and the resultant profound splanchnic hemodynamic effects are as marked during intravenous administration as during selective SMA infusion.

Actuarial analysis of variables associated with rupture of small abdominal aortic aneurysms

This study identified risk factors associated with rupture of small abdominal aortic aneurysms in patients initially selected for nonoperative management. Sixty-seven patients, 53 men and 14 women, 50 to 91 years of age (mean 72 years) were followed 3 to 99 months (mean 36 months). All patients underwent serial aortic ultrasonography. The annual rate of aneurysm rupture was 6%, with an annual mortality rate caused by rupture of 5% and an annual mortality rate caused by coexistent disease of 6%. Thirty potential risk factors, including blood pressure, aneurysm size measured by ultrasonography, rate of aneurysm expansion, smoking, serum cholesterol levels, and cardiac, pulmonary, and renal risks, were analyzed by Cox proportional hazards regression to identify variables related to rupture. Aneurysm anteroposterior expansion rates varied from 0 to 1.5 cm/year but were not different in aneurysms that ruptured. Only diastolic blood pressure, initial aneurysm anteroposterior diameter, and degree of obstructive pulmonary disease were independently predictive of rupture (p less than 0.05, Wald test). With these data, actuarial rupture rates were predicted for patients with selected values of these three covariates. Predicted 5-year rupture rates varied from 2% when these risk factors were absent to 100% when all three risk factors were significant. Obstructive pulmonary disease, initial aneurysm size, and diastolic hypertension must be evaluated prospectively to assess their accuracy in predicting small aneurysm rupture.

Celiac artery aneurysms: historic (1745-1949) versus contemporary (1950-1984) differences in etiology and clinical importance

Celiac artery aneurysms were encountered in nine patients, ranging in age from 39 to 76 years, at the University of Michigan Medical Center between 1961 and 1983. Developmental defects and atherosclerosis were etiologic factors in six cases. Four patients were without symptoms, whereas five experienced abdominal pain, including one with a ruptured aneurysm. Eight patients were subjected to surgical treatment; no deaths occurred and symptoms were resolved in all patients. A literature review of 108 celiac artery aneurysms revealed two distinct subgroups. Among 60 celiac artery aneurysms encountered before 1950, representing the historic era, 40% were infectious (usually luetic), 7% were traumatic, and 52% were of undetermined cause. Most were symptomatic, 87% ruptured, and 95% were diagnosed at postmortem examination. The contemporary era since 1950 consisted of 48 cases, including nine in the Michigan experience. Congenital or developmental medial defects of the arterial wall and atherosclerosis were the most common causes of aneurysms. Most aneurysms in the contemporary period were either asymptomatic or accompanied by vague abdominal discomfort. Rupture affected 13% of those aneurysms. Operative therapy was successfully undertaken in 91% of 43 patients during the contemporary era, including eight in the present series.

Clinical contact with the trauma patient enhances accuracy of chest roentgenogram interpretation in predicting traumatic rupture of the aorta

In a previous retrospective clinical study, we reported that clinicians having contact with the trauma patient interpreted widened mediastinum (WMED) in association with TRA with greater accuracy than did staff radiologists reviewing the same chest films (0.96 vs 0.83), while staff radiologists interpreted WMED with far greater frequency than did their clinical counterparts (0.40 vs. 0.27, p = 0.01). These findings may be related to differences in chest film interpretation or to the influence of clinical contact with the patient. To answer this question, data from a study in which a group of four surgeons and two radiologists was asked individually and in a blinded fashion to interpret, without the clinical history, the chest x-rays of 149 trauma patients who had undergone aortography to rule out TRA were examined by specialty affiliation. Sixteen of the patients had TRA. Surgeons interpreted WMED with the same frequency as radiologists (0.47 vs 0.54) and with far greater frequency (0.47 vs 0.27, p = 0.06) and poorer accuracy (0.61 vs 0.96) than they did in the previous clinical review. No significant differences were detected between surgeons and radiologists in the overall rate of interpretation of WMED, in the prediction of aortic rupture, or in the ordering of aortography based purely upon chest film interpretation. We conclude that trauma surgeons and radiologists, isolated from the patient interpret the chest film signs associated with TRA similarly. Clinical contact with the trauma patient may modify what is seen on chest film in a way that contributes to greater accuracy in the diagnosis of TRA. Radiographic criteria for ordering aortography are thus best used in conjunction with careful clinical evaluation of the patient.

Nonpenetrating subclavian artery injuries

Nonpenetrating subclavian artery trauma, a potentially catastrophic injury, has been recognized more frequently with the liberal use of angiography in evaluating blunt cervicothoracic trauma. Six patients, five men and one woman, recently underwent surgical treatment at the University of Michigan Hospital for blunt injury of the subclavian artery. The diagnoses were established by arteriography. Physical findings, chest roentgenograms, and results of noninvasive vascular evaluation were found to be nonspecific or unreliable. Operative treatment with resection of the injured arterial segments and either primary anastomosis or bypass grafting resulted in restoration of distal, upper extremity blood flow in all of the cases. One patient died 20 days after trauma from a severe associated cerebral injury. Among the five survivors, residual soft tissue and neurologic injury compromised full recovery in three. Thus, only two of the six patients survived without sequelae, a fact that underscores the seriousness of this type of subclavian artery injury.

Estimation of patient age based on plain chest radiographs

Patient age is an essential part of a clinical history, but it is not always provided by referring physicians. We assessed the ability of four radiologists with different levels of expertise (first-year resident to professor emeritus) to predict patient age based on postero-anterior and lateral chest radiographs from 171 patients. All four were able to predict age with a mean error of less than 15 years, but there were statistically significant differences among them. Surprisingly, observer experience did not correlate with accuracy of patient age estimation. While many factors probably operate, the estimation of patient age relies heavily on "gestalt."

Brachiocephalic arterial occlusions and stenoses. Manifestations and management of complex lesions

Complex stenotic and occlusive lesions involving multiple brachiocephalic arteries were encountered in 17 symptomatic patients, 25 to 76 years of age. Symptoms included hemispheric transient ischemic attacks (16), visual symptoms (ten), global cerebral ischemia (11), true syncope (six), upper extremity ischemic symptoms (eight), and frank tissue loss (one). Of 68 brachiocephalic arteries, 53 exhibited hemodynamically significant stenoses, including 21 that were totally occluded. Transthoracic surgical reconstruction consisted of bypass grafting (11), innominate artery endarterectomy (five), or proximal left common carotid endarterectomy with reimplantation into the contralateral carotid artery (one). There were no operative deaths and only one transient perioperative neurologic deficit. All patients had relief of symptoms. When multiple brachiocephalic arterial occlusions and stenoses preclude standard cervical reconstructive procedures, direct transthoracic reconstruction is appropriate and may be undertaken with acceptable risk in properly selected patients.

Reoperation for complications of renal artery reconstructive surgery undertaken for treatment of renovascular hypertension

Seventy-two secondary operations for complications of prior renal artery reconstructive surgery were undertaken in 58 patients. This experience evolved from the management of 373 patients who underwent 425 primary operations for renovascular hypertension. Secondary operations were performed 10 times in pediatric patients following 42 primary procedures (24%); 44 times in adult fibrodysplastic patients following 199 initial operations (22%); and 18 times in atherosclerotic patients after 184 primary operations (10%). The overall reoperation rate was 15.5% (58 of 373 patients). Reoperation typically followed persistent or recurrent hypertension caused by graft thromboses, perianastomotic graft narrowing, or progressive nonanastomotic graft stenoses. Aneurysmal deterioration of vein grafts was an uncommon reason for reoperation. Secondary reconstructions included nephrectomy (31), bypass with vein grafts (15) or prosthetic grafts (8), angioplasty or reimplantation (12), thrombectomy (4), and operative dilation (2). Benefits regarding hypertension control were afforded 91% of these patients. One death occurred among the 72 reoperations, representing a 1.4% operative mortality rate. Reoperative renal artery reconstructive surgery for complications of renal revascularization may present formidable technical problems. Early diagnosis and prompt reoperation with exacting vascular surgical techniques are most likely to provide optimal results.

Combined use of Doppler ultrasound and phleborheography in suspected deep venous thrombosis

Doppler ultrasound and PRG were compared with the results of venography in 216 limbs with suspected DVT. Equivocal or conflicting noninvasive test results were obtained in 40 limbs and thrombi were demonstrated venographically in 18 of these (45 per cent). In the remaining 176 limbs, the sensitivity of the noninvasive test was 88 per cent and the specificity was 99 per cent. Treatment may be confidently chosen without venographic confirmation when the results of Doppler ultrasound and PRG agree. Venography is indicated in the minority of instances when the two noninvasive test results do not agree or are equivocal.