The clinical course of new-onset atrial fibrillation after elective aortic operations

BACKGROUND

The onset of atrial fibrillation (AFIB) in the postoperative setting has been associated with increased morbidity and mortality in patients undergoing major noncardiothoracic operations. The purpose of this study was to determine the incidence, associated complications, and outcomes of AFIB after open aortic operations.

STUDY DESIGN

We studied 211 consecutive patients undergoing elective aortic operations at a single hospital during a recent 6-year period. Postoperatively all patients had continuous ECG monitoring in the ICU for a mean (+/- SD) of 6 +/- 8 days and routine cardiac enzyme determinations.

RESULTS

AFIB developed in 22 of the 211 patients (10%), a mean (+/- SD) of 2 +/- 1 days after operation, and it lasted for a mean of 4 +/- 6 days after onset. Sixteen patients spontaneously reverted to normal sinus rhythm, 3 required cardioversion (2 chemical, 1 electrical), and 3 continued in AFIB at discharge. Four of the 22 patients suffered additional cardiac complications, including antecedent MI in 3 (14%) and sustained cardiogenic shock requiring electrical cardioversion in 1. By comparison, the incidence of MI in the other 189 patients was 4% (no significant difference [NSD]). There were no deaths in the AFIB patients. Cardiac emboli developed in none of the 22 patients, and all patients had normal sinus rhythm on ECG obtained a mean of 14 +/- 10 months after discharge. Comparing the 22 patients with AFIB with the 189 patients without AFIB, there were no differences in the mean duration of ICU stay (6 +/- 4 versus 6 +/- 8 days), total length of hospital stay (10 +/- 5 versus 11 +/- 10 days), or hospital mortality (0% versus 0.5%). AFIB patients were older (71 versus 66 years, p = 0.016), but there was no difference in gender or use of beta-blockers between the two groups.

CONCLUSIONS

These data suggest that AFIB is not uncommon after aortic operations but is not associated with increased morbidity, mortality, or length of hospital stay. Although a minority of affected patients can have other cardiac complications such as MI, these complications are usually recognized before the onset of AFIB. AFIB does not affect the outcomes of aortic operations. Most patients will revert spontaneously to normal sinus rhythm and do not require longterm anticoagulation to prevent thromboembolic complications.

ANG II type 1 receptor downregulation does not require receptor endocytosis or G protein coupling

ANG II type 1 (AT(1)) receptors respond to sustained exposure to ANG II by undergoing downregulation of absolute receptor numbers. It has been assumed previously that downregulation involves endocytosis. The present study hypothesized that AT(1) receptor downregulation occurs independently of receptor endocytosis or G protein coupling. Mutant AT(1) receptors with carboxy-terminal deletions internalized <5% of radioligand compared with 65% for wild-type AT(1) receptors. The truncated AT(1) receptors retained the ability to undergo downregulation. These data suggest the existence of an alternative pathway to AT(1) receptor degradation that does not require endocytosis, per se. Point mutations in either the second transmembrane region or second intracellular loop impaired G protein (G(q)) coupling. These receptors exhibited a biphasic pattern of downregulation. The earliest phase of downregulation (0-2 h) was independent of coupling to G(q), but no additional downregulation was observed after 2 h of ANG II exposure in the receptors with impaired coupling to G(q). These data suggest that coupling to G(q) is required for the later phase (2-24 h) of AT(1) receptor downregulation.

Acute pancreatitis after abdominal vascular surgery

BACKGROUND

Retroperitoneal dissection and ischemia have been proposed as risk factors for postoperative pancreatitis. Although both are routine components of abdominal vascular operations, postoperative pancreatitis has not been adequately evaluated in vascular patients. The purpose of this study was to determine the incidence and outcomes of pancreatitis after abdominal vascular surgery.

STUDY DESIGN

We collected pre-, intra-, and postoperative data on 21 patients who developed pancreatitis after abdominal vascular operations. For comparison, we studied 21 age- and gender-matched case controls undergoing identical operations during the same period.

RESULTS

The incidence of pancreatitis among all patients undergoing abdominal vascular operations during the 6-year study period was 1.8%. Pancreatitis was diagnosed 9.8 +/- 8 days after operation and was associated with 3 or less Ranson signs in all 21 study subjects. The following outcomes data differed between the two groups: duration of npo (9 +/- 6 days for subjects versus 3.9 +/- 2 days for controls, p < 0.001) and need for parenteral nutrition (13 subjects versus no controls, p < 0.00 1). Although there was a trend towards longer hospitalization in the subjects (16 +/- 12 days versus 11 +/- 8 days, p = 0.08), there was no difference in complication rates between the two groups. Sixteen subjects (76%) had no complications. Three developed severe complications, two of whom died of causes unrelated to pancreatitis. One developed a pseudocyst that resolved spontaneously. Cholelithiasis was a causative factor in 2 subjects; no cause was established in the remaining 19. There was no difference in operative details between the two groups.

CONCLUSIONS

These data indicate that pancreatitis is a rare and self-limited complication of abdominal vascular surgery. Our findings suggest that pancreatitis is costly and inconvenient but rarely serious after abdominal vascular operations.

Watchful waiting in cases of small abdominal aortic aneurysms- appropriate for all patients?

OBJECTIVE

The purpose of this study was to determine the effect of patient compliance on a program of watchful waiting in cases of small abdominal aortic aneurysms and to document the proportion of patients who become prohibitive operative risks during follow-up.

STUDY DESIGN

A retrospective review was conducted at a regional military veterans medical center. The subjects were 101 male military veterans with abdominal aortic aneurysms measuring less than 5 cm who did not have medical contraindications to operative repair. The main outcome measures were (1) the proportion of patients who missed three scheduled radiologic tests in a row despite written notifications mailed to their homes and (2) the proportion of compliant patients who had medical illnesses and became prohibitive operative risks during follow-up.

RESULTS

During a follow-up (mean +/- SEM) of 34 +/- 2 months, 69 patients (69%) were fully compliant with the watchful waiting program and underwent a mean of 4.5 +/- 0.3 radiologic tests. There were no abdominal aortic aneurysm ruptures in this subgroup. Twenty-five patients (36%) had indications for abdominal aortic aneurysm repair, and 28 (41%) have not met the criteria for repair. Sixteen (23%) of the 69 compliant patients developed prohibitive medical risks during follow-up; eight (50%) of these 16 patients died, all of the causes unrelated to their abdominal aortic aneurysms. Thirty-two (32%) of the 101 study subjects were noncompliant with the watchful waiting program. Twenty-seven (84%) of the noncompliant patients did not keep any scheduled appointments, and five (16%) were lost after one or two examinations. Three of the noncompliant patients experienced documented abdominal aortic aneurysm rupture, and it is suspected in a fourth. Direct contact was made with 28 (88%) of these patients or their families; all acknowledged having received written notifications regarding their watchful waiting program tests and had decided not to continue with surveillance for a variety of socioeconomic reasons. Between the 69 compliant patients and the 32 noncompliant patients, there were no differences with respect to mean age (70 +/- 1 years vs 73 +/- 2 years), distance from home of record to the hospital (62 +/- 14 miles vs 73 +/- 23 miles), or abdominal aortic aneurysm size at initial detection (3.75 +/- 0.5 cm vs 3.8 +/- 0.5 cm).

CONCLUSIONS

Watchful waiting programs are imperfect and highly reliant on the motivation levels and means of the individual patients. Watchful waiting is reasonable among compliant patients with abdominal aortic aneurysms, inasmuch as fewer than half will meet the criteria for intervention within a mean of 3 years. Approximately one fourth of these patients will have medical contraindications to abdominal aortic aneurysm repair during follow-up, and many of these will die of causes other than abdominal aortic aneurysm rupture. In our experience, one third of candidates for watchful waiting programs are unable to participate and are at risk of rupture. These patients need special attention so that the reasons for their noncompliance can be determined, and they may be candidates for earlier intervention.

The consequences of a failed femoropopliteal bypass grafting: comparison of saphenous vein and PTFE grafts

OBJECTIVES

Although there are numerous reports comparing saphenous vein (SV) and polytetrafluoroethylene (PTFE) with respect to the patency rates for femoropopliteal bypass grafts, the clinical consequences of failed grafts are not as well described. This study compares the outcomes of failed SV and PTFE grafts with a specific emphasis on the degree of acute limb ischemia caused by graft occlusion.

METHODS

Over a 6-year period, 718 infrainguinal revascularization procedures were performed, of which 189 were femoropopliteal bypass grafts (SV, 108; PTFE, 81). Society for Vascular Surgery/International Society for Cardiovascular Surgery (SVS/ISCVS) standardized runoff scores were calculated from preoperative arteriograms. Clinical categories of acute limb ischemia resulting from graft occlusion were graded according to SVS/ISCVS standards (I, viable; II, threatened; III, irreversible). Primary graft patency and limb salvage rates at 48 months were calculated according to the Kaplan-Meier method.

RESULTS

Patients were well matched for age, sex, and comorbidities. Chronic critical ischemia was the operative indication in most cases (SV, 82%; PTFE, 80%; P =.85). Runoff scores and preoperative ankle-brachial index measurements were similar for the two groups (SV, 6.0 +/- 2.5 [SD] and 0.51 +/- 0.29; PTFE, 5.3 +/- 2.8 and 0.45 +/- 0.20; P =.06 and P =.12). The distal anastomosis was made below the knee in 60% of SV grafts and 16% of PTFE grafts (P <.001). Grade II ischemia was more likely to occur after occlusion of PTFE grafts (78%) than after occlusion of SV grafts (21%; P =.001). Emergency revascularization after graft occlusion was required for 28% of PTFE failures but only 3% of SV graft failures (P <.001). Primary graft patency at 48 months was 58% for SV grafts and 32% for PTFE grafts (P =.008). Limb salvage was achieved in 81% of SV grafts but only 56% of PTFE grafts (P =.019).

CONCLUSIONS

Patients undergoing femoropopliteal bypass grafting with PTFE are at greater risk of ischemic complications from graft occlusion and more frequently require emergency limb revascularization as a result of graft occlusion than patients receiving SV grafts. Graft patency and limb salvage are superior with SV in comparison with PTFE in patients undergoing femoropopliteal bypass grafting.

The role of imaging techniques in evaluating possible graft infections

Imaging plays a central role in the management of graft infections. Most graft infections are clinically apparent, and imaging techniques are used primarily for diagnostic confirmation and operative planning. The accurate diagnosis of less overt graft infections requires a thorough understanding of the available imaging options. Late aortic graft infections (more than 3 months postoperative) are best evaluated initially by computed tomography (CT) or magnetic resonance (MR) scanning. CT findings consistent with a graft infection include ectopic gas, perigraft fluid, perigraft inflammatory changes, anastomotic pseudoaneurysm, and thickening of adjacent bowel. MRI offers the additional advantage of T2-weighted images to identify perigraft inflammation and minute quantities of perigraft fluid. Radionuclide scanning techniques such as 111indium-labeled WBC scans are highly sensitive but suffer from a relative lack of specificity. Duplex ultrasonography is best applied to the diagnosis of late infections of superficial grafts. Sonographic findings of a graft infection include perigraft fluid and pseudoaneurysms. The imaging of early postoperative grafts (less than 3 months) for infection is problematic because perigraft fluid and inflammatory changes persist for up to 3 months postoperatively. Suspected early graft infections often require operative exploration for diagnosis. A thorough understanding of the utility and limitations of imaging techniques will enable the clinician to develop a reasonable diagnostic algorithm that is appropriate for each case.

The progressive nature of peripheral arterial disease in young adults: a prospective analysis of white men referred to a vascular surgery service

OBJECTIVE

The onset of symptomatic peripheral arterial disease at a young age (premature PAD) has been associated with rapid progression, bypass graft failure, and amputation. This study was performed to document the incidence of these complications and to determine the risk factors for poor outcome in patients with premature PAD.

METHODS

This study was designed as a prospective longitudinal analysis, with patients who were ambulatory or hospitalized at a single vascular referral institution. The subjects were 51 white men with onset of PAD symptoms before the age of 45 years (mean age of onset, 41 +/- 0.5 years) and represented consecutive patients who were seen at the vascular surgery service during a 4-year period. Thirty of the study subjects (58%) were recruited during the first 2 years. The main outcome measures were number and type of lower extremity revascularization procedures or amputations that were necessitated during the follow-up period.

RESULTS

During a mean follow-up period of 73 +/- 6 months, 15 patients (29%) had PAD that remained stable without interventions and 15 (29%) had PAD that remained stable for a mean of 76 +/- 13 months after a single intervention. Twenty-one patients (41%) required multiple operations or major amputations. In a comparison of the 30 PAD patients whose conditions were stable with or without a single intervention with the 21 PAD patients who required multiple interventions (REDO), there were no differences in smoking, hypertension, diabetes, or dyslipidemias. The REDO group had a younger mean age at the onset of symptoms (39 +/- 1 years vs 43 +/- 2 years; P <.001). At entry, the REDO patients had a higher prevalence of infrainguinal or multilevel disease (57% vs 20%; P =.03), a lower mean ankle brachial index (0. 44 +/- 0.04 vs 0.56 +/- 0.03; P =.02), and more frequent tissue loss (24% vs 0; P =.005). The REDO patients had a higher mean lipoprotein (a) level than did the patients with stable conditions (51 +/- 11 mg/dL vs 27 +/- 5 mg/dL; P =.03), but there were no significant differences in the mean plasma homocysteine levels (19 +/- 2 micromol/L vs 16 +/- 1 micromol/L) or in the proportion of patients with hypercoagulable states (33% vs 30%). The only predictive variables that were selected with stepwise logistic regression analysis were age at onset (P <.002; odds ratio, 1.4; 95% confidence interval, 1.11 to 1.81) and ankle brachial index of less than 0.5 (P <.008; odds ratio, 6.4; 95% confidence interval, 1.5 to 27.3).

CONCLUSION

Although 60% of the white men with premature PAD who were referred to a vascular surgery service had conditions that appeared to remain stable, these data show that approximately 40% of the patients will require multiple interventions because of disease progression or bypass graft failure. Clinical indicators, not serum markers, are predictors of poor outcome in patients with premature PAD. The results of this study suggest that patients with onset of PAD before the age of 43 years who have objective evidence of advanced disease are predisposed to multiple interventions.

Complex aortofemoral prosthetic infections: the role of autogenous superficial femoropopliteal vein reconstruction

BACKGROUND

With increasing experience, we have encountered patients with complex aortofemoral prosthetic infections in whom extra-anatomic bypass (EAB) is not an option.

HYPOTHESIS

Autogenous superficial femoropopliteal vein (SFPV) aortic reconstruction provides a limb-saving and lifesaving alternative with acceptable morbidity and mortality.

DESIGN

Retrospective review.

SETTING

University-based county, private, and Veterans Affairs hospitals.

PATIENTS

Seventeen patients with infected aortofemoral bypasses in whom conventional EAB was impossible because of infection of previously placed EAB, massive groin and/or thigh sepsis, or both.

MAIN OUTCOME MEASURES

Morbidity and mortality.

RESULTS

Multiple previous operations were common (mean, 4 per patient) and included EAB (n = 11), replacement aortofemoral bypass (n = 4), prosthetic femoropopliteal bypass (n = 7), and thoracobifemoral bypass (n = 1); all bypasses became infected. Overall, 11 patients had sepsis at the time of presentation. Of the patients with massive groin infection, 7 had extensive deep infections involving most of the proximal thighs or retroperitoneum, 4 had enterocutaneous fistulae, and 2 had necrotizing fasciitis of the lower abdomen and thigh. Polymicrobial infections were common (n = 9). Four patients (24%) died in the perioperative period, 8 (47%) suffered major complications, and 4 (24%) underwent major amputations. Mortality in this group of patients was 3 times that of all other patients undergoing autogenous SFPV aortic reconstruction for prosthetic infection (8%). Amputation rates were also increased (24% vs 6%). The mean+/-SD follow-up time is 23+/-21 months. All patients maintained patent SFPV reconstructions.

CONCLUSIONS

In the setting of complex aortofemoral prosthetic infections, autogenous SFPV aortic reconstruction is a useful option for patients in whom EAB is impossible and limb loss and/or death would be inevitable without revascularization.

Diagnosis and management of penetrating vascular trauma and the injured extremity

Early diagnosis and timely treatment of extremity vascular injuries are essential if limb salvage and limb function are to be optimized. Careful and repeated clinical examination and ankle/brachial doppler indices are pivotal for early diagnosis. Routine arteriography for proximity injury is neither cost effective nor clinically indicated and minimal non-occlusive arterial injuries do not require vascular repair. An algorithm for the diagnostic evaluation and treatment of patients with penetrating extremity trauma is presented. The early diagnosis of compartment syndrome is stressed.

Acute suprarenal aortogastric fistulae caused by gunshot wounds: the importance of early recognition in directing surgical strategy

Penetrating suprarenal aortic injuries carry high mortality rates. Difficulties in surgical exposure and bleeding control in this area add to the ominous prognosis. In rare occasions, synchronous injury to the adjacent upper part of stomach may lead to an acute aortogastric fistula, resulting in aortic bleeding into the stomach instead of the peritoneal cavity. Filling of the stomach with blood may temporarily tamponade the aortic perforation. Distortion of this delicate communication during dissection before proximal and distal vascular control is achieved could result in catastrophic hemorrhage. Therefore, recognition of the importance of a fully distended stomach at the suspicion of aortic injury is essential in directing a particular surgical strategy that aims to achieve an unrestricted operative exposure and successful bleeding control.

Syme amputation: results in patients with severe forefoot ischemia

Since 1980, 35 patients (age range 40-77 years) with severe forefoot ischemia have undergone a unilateral Syme amputation. Thirty-one patients (89%) were diabetic. The indication for amputation was either extensive forefoot gangrene or ulceration too advanced for a digital or transmetatarsal amputation. Twenty-two amputations (63%) were immediately preceded by either percutaneous transluminal angioplasty (four) or a bypass procedure to the popliteal artery (five) or an infrapopliteal artery (13). Primary healing occurred in 19 (86%) of 22 amputations immediately preceded by revascularization and in 10 (77%) of 13 limbs undergoing amputation alone. Twenty-eight (97%) of the 29 patients with successful primary healing were successfully rehabilitated. Rehabilitation rendered 13 patients fully ambulatory, 15 ambulatory with intermittent use of a walker or cane and one unable to walk. At follow-up of four months to 13 years (mean 42 months), the cumulative ambulatory rate at 1, 3, and 5 years was 92, 80 and 80%, respectively. Syme amputation allows a return to a functional ambulatory status in a high percentage of patients with severe forefoot ischemia. These findings suggest that Syme amputation is an acceptable option in dysvascular patients with severe forefoot ischemia.

Concurrent abdominal aortic aneurysm and urologic neoplasm: an argument for simultaneous intervention

This report describes the surgical management of 24 patients with concurrent abdominal aortic aneurysm (AAA) and urinary tract neoplasm. The patient population consisted of 22 men and two women whose average age was 65.5 years. AAA sizes ranged from 3.1 to 9.0 cm (mean 5.2 cm) in diameter. Urinary tract neoplasms included transitional cell carcinoma (TCC) of the bladder (n = 19), adenocarcinoma of the prostate (n = 3), and TCC of the renal pelvis (n = 2). Urologic procedures included radical prostatectomy, radical nephroureterectomy, and radical cystoprostatectomy with continent or ileal loop urinary diversion. The AAA was resected at the time of the urologic procedure in 12 patients (group I) or prior to the urologic procedure in five patients (group II) and was left in situ in seven patients (group III: AAA diameter 3.1 to 5.5 cm). All patients but one in group I recovered without complications. One patient developed an infection postoperatively as a result of fluid collection anterior to the aortic vascular graft; the fluid was successfully drained and the patient subsequently recovered uneventfully. All patients in group II had a marked retroperitoneal desmoplastic reaction at the time of the urologic procedure as a result of prior aneurysmectomy, which complicated the ureteral dissection. One patient later required an ileal ureteral reconstruction for obliterative fibrosis of the ureter. At a mean follow-up of 34 months, no infectious or mechanical complications of the vascular prosthesis occurred in group I or II. Eight patients in group I and two in group II are alive. Three have died of metastatic disease and two of myocardial infarction. Of the seven patients in group III, four subsequently required AAA resection for an increase in AAA size and three have died.(ABSTRACT TRUNCATED AT 250 WORDS)

Upregulation of angiotensin II type 1 receptor gene expression in chronic renovascular hypertension

Although the renin-angiotensin system has been implicated in the pathogenesis of renovascular hypertension (RVH), blood pressure does not parallel serum levels of renin or angiotensin II (AII) in chronic RVH. Upregulation of angiotensin II type 1 receptor (AT1) gene expression may explain this paradox and clarify the pathogenesis of chronic hypertension in RVH. To investigate this hypothesis, we studied changes in AT1 mRNA levels in rat kidney in a two-kidney, one-clip (2K1C) rat model of RVH. Animals were sacrificed at 1 or 10 weeks postoperatively. Blood pressure was measured with a tail cuff photosensor. Relative gene expression was quantitated by dot blotting total RNA, hybridizing with a cDNA probe for AT1, and quantitating signal intensity with scanning densitometry. A significant increase in blood pressure (BP) was observed at 1 week postoperatively (delta BP: 2K1C = +24 mm Hg, n = 3; controls = +7 mm Hg, n = 3; P < 0.05), and at this time relative AT1 mRNA levels actually decreased in the clipped kidney (P < 0.05). Hypertension intensified 10 weeks postoperatively (delta BP: 2K1C = +46 mm Hg, n = 20; controls = -17 mm Hg, n = 7; P < 0.005) and, remarkably, was paralleled by an almost sevenfold upregulation of AT1 mRNA levels in the clipped kidney (P < 0.005) and more than eightfold in the unclipped kidney (P < 0.005) of 2K1C animals. Upregulation of renal AT1 gene expression could lead to increased AT1 receptor production, hypersensitivity to AII, and chronic hypertension in RVH.

Advances in the treatment of phlegmasia cerulea dolens

Phlegmasia cerulea dolens (PCD) is an uncommon, severe form of lower extremity deep venous thrombosis characterized by extremity swelling, cyanosis, and pain. Progression of the thrombotic process may result in extremity gangrene, amputation, and death. The relative value of specific therapeutic regimens in the treatment of this disease remains uncertain. Twelve patients, 9 females and 3 males, with PCD were treated during a 10-year period. Eighteen lower extremities were involved. Pre-existing conditions included malignancy (eight), postoperative state (four), diabetes (three), previous deep venous thrombosis (three), and hypercoagulation (two). Venous gangrene was present in four patients. All patients were treated initially with bedrest, fluid resuscitation, extremity elevation, and systemic high-dose heparin therapy. Five patients had complete resolution with this regimen alone. One patient required cessation of heparin therapy due to heparin-induced thrombocytopenia and developed gangrenous toes. Two patients whose condition failed to respond to heparin therapy underwent catheter-based delivery of urokinase with marked clinical improvement. Four patients, two with venous gangrene, died, three of whom had disseminated malignant disease. A significant percentage of patients with PCD will respond to extremity elevation, fluid resuscitation, and aggressive systemic anticoagulation therapy. Thrombolytic therapy selectively administered is beneficial in patients whose disease fails to respond promptly. Venous thrombectomy should be reserved for patients with contraindications to thrombolysis.

Angiotensin II increases glucose utilization during acute hyperinsulinemia via a hemodynamic mechanism

To determine whether hemodynamic changes can modulate insulin action in vivo, we administered angiotensin II (AII) to normal men under three separate, euglycemic conditions. First, in the presence of physiological hyperinsulinemia (approximately 115 microU/ml), infusion of AII at rates of 2, 10, and 20 ng/min per kg caused significant elevations of blood pressure, whole-body glucose clearance, and plasma insulin concentrations in an AII dose-dependent manner. Second, in the presence of plasma insulin concentrations that stimulate glucose transport maximally (approximately 5,000 microU/ml), AII infusions increased whole-body glucose clearance without enhancing glucose extraction across the leg. Third, in the presence of basal insulin concentrations (approximately 13 microU/ml), AII infusions had no effect on whole-body glucose turnover or leg glucose extraction. Thus, AII enhanced whole-body glucose utilization without directly stimulating glucose transport in a major skeletal muscle bed. To evaluate a possible hemodynamic mechanism for the effects of AII on glucose utilization, we measured blood flow to two areas that differ in their sensitivity to insulin: the kidneys and the leg. We found that AII redistributed blood flow away from the predominantly insulin-independent tissues of the kidney and toward the insulin-sensitive tissues of the leg during both sham and hyperinsulinemic glucose clamps. The redistribution of flow had no effect on whole-body glucose turnover when leg glucose uptake was unstimulated (sham clamps). However, when leg glucose uptake was activated by insulin, the redistribution of flow caused a net increase in whole-body glucose utilization. Our findings indicate that hemodynamic factors can modulate insulin action in vivo. Furthermore, our results suggest that variable activity of the renin-angiotensin system may contribute to inconsistencies in the association between insulin resistance and hypertension.

Vascular considerations in extremity trauma

Effective diagnosis and management of associated vascular injuries is imperative to minimize morbidity after extremity trauma. An algorithm is presented for the diagnostic evaluation of patients with extremity trauma. The value of physical examination and Doppler indices in identifying occult injuries is discussed. The natural history of certain occult, nonocclusive injuries suggests that nonoperative management may be considered. The intraoperative management of major arterial and venous injuries, including current controversies, is addressed also.