Useful predictors of bile duct stones in patients undergoing laparoscopic cholecystectomy. McGill Gallstone Treatment Group

OBJECTIVE

The authors determined the most useful predictors of common bile duct (CBD) stones as diagnosed by endoscopic retrograde cholangiopancreatography (ERCP) in patients who underwent laparoscopic cholecystectomy (LC).

METHODS

Prospective and retrospective collection of historical, biochemical and ultrasonographic data was used. Receiver operating characteristics curve analysis was used to determine optimal biochemical cut-off values. Multivariate analysis using logistic regression with generation of the best model identifying independent predictors of CBD stones also was employed. Prospective validation of the model was performed on an independent group of patients.

RESULTS

Endoscopic retrograde cholangiopancreatographies were performed before LC in 106 patients, and after LC in 33. Only four of ten clinical variables evaluated independently predicted the presence of CBD stones. The optimal model predicted a 94% probability of CBD stones in a patient older than 55 years of age who presented with an elevated bilirubin (over 30 mumol/L) and positive ultrasound findings (a dilated CBD, and a CBD stone seen on ultrasound). This model was validated prospectively in a subsequent series of 49 patients in which the probability of CBD stone was only 8% when all four predictors were absent.

CONCLUSIONS

The identified independent clinical predictors of a CBD stone helps select a population of symptomatic gallstone bearers who benefit most from cholangiographic assessment.

Carotid artery duplex scanning in preoperative assessment for coronary artery revascularization: the association between peripheral vascular disease, carotid artery stenosis, and stroke

PURPOSE

The purpose of this study was to identify high-risk populations for severe carotid artery disease (SCD) and neurologic events (NE) after nonemergency isolated coronary artery bypass graft procedures (CABG).

METHODS

Between February 1989 and July 1992, 387 patients underwent preoperative carotid artery duplex scanning as part of a preoperative assessment for nonemergency cardiac procedures. Of these patients, 376 had isolated CABG, and 11 had combined carotid endarterectomy (CEA) and CABG. Patient demographics, risk factors, and preoperative neurologic symptoms were recorded and analyzed. Severe carotid artery disease was defined as a 80% or greater stenosis of either internal carotid artery by carotid artery duplex scanning. Patients were evaluated for neurologic events (cerebrovascular accident, transient ischemic attack, amaurosis fugax, or reversible ischemic neurologic deficits) during the in-hospital postoperative period.

RESULTS

The prevalence of SCD was 8.5% (33 patients). The 33 patients with SCD were significantly older (65.6 +/- 6.5 years vs 62.5 +/- 10.4 years, p = 0.02), had previous CEA (27.3% vs 2.0%, p = 0.00001), had preoperative neurologic symptoms (21.2% vs 5.9%, p = 0.002), and had peripheral vascular disease (PVD) (63.6% vs 16.9%, p = 0.00001). The sensitivity of PVD for SCD is 63.6% (n = 21/33) (specificity 83.1%, positive predictive value 25.9%, negative predictive value 96.1%). In patients undergoing CABG alone, those who had postoperative NE were older (69.6 +/- 6.7 years vs 62.5 +/- 10.3 years, p = 0.036) and more likely to have PVD (50% vs 19.7%, p = 0.034), SCD (40% vs 4.9%, p = 0.001) and previous CEA (40% vs 2.7%, p = 0.0002). The incidence of postoperative NE in patients with SCD was 18.2% vs 1.7% in patients without SCD (p = 0.001). The sensitivity of SCD for NE was 40% (n = 4/10) (specificity 95.1%, positive predictive value 18.2%, negative predictive value 98.3%).

CONCLUSIONS

PVD may be helpful to identify patients at high risk for severe carotid artery stenosis. Postoperative NE in patients with CABG are associated with increasing age, carotid artery stenosis greater than 80%, previous CEA, and PVD.

Perioperative blood transfusion and outcome after resection for colorectal carcinoma

The degree of immunomodulation by perioperative blood transfusion and its effect on oncological surgery remain controversial. A major problem with previous clinical studies has been the inadequate patient population in each and the presence of confounding variables. To resolve some of the controversy, all studies published between 1982 and 1990 were reviewed using the statistical method of Mantel-Haentszel-Peto to determine a cumulative estimate of the direction and magnitude of this association. Some 20 papers were included in the analysis, representing 5236 patients. The cumulative odds ratios (95 per cent confidence interval) of disease recurrence, death from cancer and death from any cause were 1.80 (1.30-2.51), 1.76 (1.15-2.66) and 1.63 (1.12-2.38) respectively. These results support the hypothesis that perioperative blood transfusion is associated with an increased risk of recurrence of colorectal carcinoma and death from this malignancy.

Incidence of major venous and renal anomalies relevant to aortoiliac surgery as demonstrated by computed tomography

Preoperative knowledge of the presence of major venous anomalies facilitates the safe performance of aortic surgery. The purpose of the study was to estimate the incidence, as detected by abdominal and pelvic computed tomography (CT), of major venous and renal anomalies related to the abdominal aorta in an adult population. A total of 1822 intravenous contrast-enhanced abdominal and pelvic CT scans done in 1822 patients at two university teaching hospitals were randomly selected and prospectively reviewed (between June 1999 and March 2000) to identify major venous and renal anomalies associated with the abdominal aorta and iliac arteries. An interpreting staff radiologist then indicated on adata sheet whether any of the following anomalies were present or absent: (1) retroaortic left renal vein, (2) circumaortic left renal vein, (3) left-sided inferior vena cava (IVC) without situs inversus, (4) left-sided IVC with situs inversus, (5) duplicate IVC, (6) preaortic confluence of the iliac veins, or (7) horseshoe kidney. The CT scans reviewed had been performed for a wide variety of indications. Thirty-four scans were excluded from the study because either the anomalies we were looking for could not be assessed for technical reasons or the patient had a previous left nephrectomy and therefore assessment of the left renal vein was impossible. From this analysis we found that in an adult population, the prevalence of major venous and renal anomalies related to the abdominal aortaand iliac arteries and detected by CT scan was 5.65%. Prior to aortic surgery, preoperative knowledge of the presence of such anomalies helps with operative planning and may reduce the risk of major venous hemorrhage associated with these anomalies.

Early vascular complications after endovascular repair of aortoiliac aneurysms

The purpose of this study was to estimate the frequency of and review the treatment options for intraoperative endograft access-related vascular complications and early postoperative vascular complications of endovascular repair for aortoiliac aneuryms (EVAR). Between February 1998 and April 2000, 53 patients (46 males, 7 females) with aneurysms of the abdominal aorta (AAA) and iliac arteries were treated with endovascular grafts (48 AAA, and 5 iliac aneurysms). All procedures were performed using open exposure of the femoral arteries. One patient with an AAA was converted to open repair (primary technical success, 98.1%). We recorded the need for adjunctive vascular procedures or intervention to the access arteries (iliofemoral) or the endograft because of thrombosis or distal embolization. Events were classified as either intraoperative, early postoperative (< 30 postoperative days), or late postoperative. Their etiology and treatment were recorded. The results were compared to those from other series reported in the literature and to published registry data. From our results we concluded that the need for adjunctive vascular procedures to the iliofemoral arteries at the time of EVAR is significant. These procedures are necessary to either repair damage to the access arteries from the delivery system or provide a conduit for graft delivery in cases where the access arteries are inadequate. Early postoperative vascular complications are due to technical factors resulting in residual graft limb stenoses. Both intraoperative and early postoperative vascular complications after EVAR are more common in female patients. These complications can be effectively treated with a variety of open surgical and transfemoral endovascular techniques.

Treatment of femoral artery pseudoaneurysms with percutaneous thrombin injection

The objective of this study was to prospectively evaluate the efficacy of ultrasound-guided thrombin injection for the treatment of post-catheterization femoral artery pseudoaneurysms. Between August 1, 1998 and August 31, 1999, 38 patients underwent ultrasound-guided injection of thrombin into 39 femoral false aneurysms. Peripheral pulses and ankle/brachial indices were assessed before and after the injection. Patients were followed with a control duplex scan within 4 weeks. The good results from this study showed that ultrasound-guided thrombin injection is an effective method for the treatment of post-catheterization false aneurysms. In a minority of patients, signs consistent with arterial embolization or vasospasm were identified.

Association of ultrasonic texture and echodensity features between sides in patients with bilateral carotid atherosclerosis

OBJECTIVES

Our objective was to estimate the correlation of echodensity and textural features, using ultrasound and digital image analysis, between plaques in patients with bilateral carotid stenosis.

DESIGN

Cross-sectional observational study.

METHODS

Patients undergoing carotid endarterectomy were recruited from Vascular Surgery at the Royal Victoria and Jewish General hospitals in Montreal, Canada. Bilateral pre-operative carotid ultrasound and digital image analysis was performed to extract echodensity and textural features using a commercially available Plaque Texture Analysis software (LifeQMedical Ltd). Principal component analysis (PCA) was performed. Partial correlation coefficients for PCA and individual imaging variables between surgical and contralateral plaques were calculated with adjustment for age, sex, contralateral stenosis, and statin use.

RESULTS

In the whole group (n = 104), the six identified PCA variables and 42/50 individual imaging variables were moderately correlated (r = .211-.641). Correlations between sides were increased in patients with ≥50% contralateral stenosis and symptomatic patients.

CONCLUSION

Textural and echodensity features of carotid plaques were similar between two sides in patients with bilateral stenosis, supporting the notion that plaque instability is determined by systemic factors. Patients with unstable features of one plaque should perhaps be monitored more closely or treated more aggressively for their contralateral stenosis, particularly if this is hemodynamically significant.

Intraoperative duplex scanning for carotid endarterectomy

OBJECTIVES

To evaluate the results of intraoperative duplex scans during carotid endarterectomy.

DESIGN

Retrospective case review.

MATERIALS

One-hundred consecutive intraoperative carotid duplex scans performed during carotid endarterectomy between July 1993 and December 1995 at a university teaching hospital.

METHODS

Abnormalities of the B-mode image and/or the Doppler flow analysis were classified. The result of intraoperative carotid duplex scans (ICDS) were related to the events of the intraoperative course, perioperative neurologic morbidity and mortality, and to residual carotid stenosis.

RESULTS

Abnormalities of the ICDS were demonstrated in 13 cases (13%). Abnormalities were classified into four types: I, internal carotid artery spasm (n = 9); II, high distal resistance flow (n = 2); III, high grade residual stenosis (n = 1); IV, intraluminal thrombosis (n = 1). Immediate intraoperative exploration and revision of the endarterectomy was performed based on the ICDS in two cases (type III and IV) and the findings of ICDS were confirmed. The other 11 cases with abnormal ICDS (types I, II) were not revised and duplex scans done 1 month postoperatively (available in 10 cases) showed normal carotid artery flow. Intraoperative angiography was performed selectively in five cases and confirmed the results of ICDS. Reversible abnormalities of the ICDS were not associated wit perioperative morbidity or residual carotid stenosis.

CONCLUSIONS

Intraoperative carotid duplex scanning can be used to assess the immediate technical adequacy of carotid endarterectomy. B-mode image and Doppler flow abnormalities which are reversible can be distinguished from those which require immediate revision.

The predictive value of intraoperative duplex for early vein graft patency in lower extremity revascularization

This study was undertaken to evaluate the ability of intraoperative duplex scanning during infrainguinal vein bypass to identify technical abnormalities and to determine the relation between intraoperative scan result and early primary graft patency. We retrospectively reviewed of 78 consecutive intraoperative duplex scans for infrainguinal vein bypass that were performed between October 1993 and October 1996 during the course of infrainguinal vein bypass. Duplex scans were classified as normal or abnormal based on B-mode image and/or Doppler velocity spectra. Grafts were grouped according to duplex findings and intraoperative action: group I, normal intraoperative scan; group II, abnormal intraoperative scan, revised; group III, abnormal intraoperative scan, not revised. The relationship of intraoperative duplex scan findings to intraoperative graft revision to 1-month and 6-month primary graft patency by life table was analyzed. The analysis demonstrates that the results of intraoperative duplex scans can be used to identify grafts at low risk for early postoperative graft failure (groups I and II), and those at high risk for early postoperative graft failure (group III).

Videoendoscopic thoracic aorta-to-femoral artery bypass. A feasibility study in a canine model

PURPOSE

This study was undertaken to determine whether videoendoscopic thoracic aorta-to-femoral artery bypass is a technically feasible operation.

METHODS

An acute canine study involving five mongrel dogs was carried out. After the dogs had been given a general anesthetic, the femoral arteries were exposed in the traditional fashion. On the left side, a retroperitoneal, retrorenal tunnel was extended from the common femoral artery to the diaphragm. Under videoendoscopic control, the tunnel was opened through the posterior thoracic attachments of the diaphragm into the thoracic cavity. A Dacron graft was tunneled from the thoracic cavity on the left to the left groin. The thoracic aorta was controlled with a side-biting clamp, and an endoscopically performed end graft-to-side thoracic aortic anastomosis was created. After completion of the thoracic anastomosis, the left femoral anastomosis was created in a traditional manner. A left-to-right femoral bypass completed the lower extremity vascular procedure. An open thoracotomy was avoided.

RESULTS

Videoendoscopic thoracic aorta-to-femoral artery bypass was successfully performed in all five animals. All components of the thoracic procedure, including exposure, dissection, vessel control, cross-clamping, and anastomosis, were performed through the thoracic ports with conventional laparoscopic instruments. Blood loss was minimal. All animals survived the procedure before being killed.

CONCLUSION

Videoendoscopic thoracic aorta-to-femoral artery bypass is a technically feasible operation in a canine model. Advantages of this unique approach over the experimental laparoscopic and the traditional transperitoneal open aortofemoral bypass include ease of aortic exposure, ability to control a segment of disease-free aorta, and anastomosis in a disease-free segment of aorta. Potential advantages include decreased perioperative morbidity rates with the videoendoscopic approach. Before there is clinical consideration of this surgical approach, long-term experiments are required to demonstrate the safety of the procedure.

Hemispheric stroke following cardiac surgery: a case-control estimate of the risk resulting from ipsilateral asymptomatic carotid artery stenosis

A case-control study was undertaken to determine if asymptomatic carotid artery stenosis (ACS) is independently associated with ipsilateral hemispheric stroke following cardiac surgery (CS). All CS patients (3069) who were at two hospitals between 1989 and 1994 were reviewed. Cases (31) selected for this study were those with hemispheric stroke within 30 days following CS. Controls (69) were taken from those without hemispheric stroke. Case-control analysis demonstrated that ACS of 50-90% and of 80-90% increased the risk of ipsilateral stroke 5.2-fold (95% confidence interval [CI] = 1.5-16.3, p = 0.01) and 24.3-fold (CI = 2.6-114.9, p = 0.002), respectively. Other variables with significant odds ratios (OR) were age > or =65 years (OR = 4.0, CI = 1.3-10.5, p = 0.01), peripheral vascular disease (OR = 3.4, CI = 1.3-8.8, p = 0.02), hypertension (OR = 3.0, CI = 1.2-7.0, p = 0.02), and female gender (OR = 3.0, CI = 1.2-7.1, p = 0.04). A second conservative analysis for missing data demonstrated a significant association for ACS of 80-90% alone (OR = 13.1, CI = 1.5-60.9, p = 0.01). This association remained significant after multivariate adjustment with propensity score stratification. ACS (80-90%) appears to be independently associated with ipsilateral hemispheric stroke following CS when evaluated against the present study variables. This finding supports the need for a properly conducted prospective natural history study, including an evaluation of aortic arch atherosclerosis, to determine the clinical relevance of this observation.

PDGF-B gene single-nucleotide polymorphisms are not predictive for disease onset or progression of IgA nephropathy

BACKGROUND

Few genetic factors have been identified that determine susceptibility to and progression of IgA-nephropathy (IgAN). Given that IgAN is usually characterized by mesangioproliferative glomerulonephritis and that PDGF-B is of central pathophysiological relevance in this process, we analyzed four single-nucleotide polymorphisms (SNPs) of the PDGF-B gene to evaluate a possible association of these SNPs with disease onset and progression, histological grading and responses to ACE inhibitor (ACEi) therapy.

METHODS

The total study population consisted of 195 IgAN patients (127 from southern Italy and 68 from northern Germany) and 200 healthy controls (100 from each region). All four SNPs were in Hardy-Weinberg equilibrium and genotype distributions did not differ between patients and controls in either region.

RESULTS

SNP distribution in Italian patients reaching end-stage renal disease (n=45) also was not significantly different from patients maintaining a serum creatinine below 1.2 mg/dl (n=60) during 5.6 +/- 5.5 years of follow-up. Furthermore, we failed to detect significant effects of any SNP on the slope of 1/serum creatinine, proteinuria level or the antiproteinuric response to ACEi. Additionally, particular PDGF-B genotypes did not correlate with histological grading using the Lee classification.

CONCLUSION

We conclude that none of the four PDGF-B SNPs is related to the onset of IgAN in two different populations and that none of them has a major influence on the course of IgAN.

Ureteropelvic urinary extravasation due to iliac artery aneurysm

We report a case of left-sided hydronephrosis and ureteropelvic urinary extravasation due to a large left iliac artery aneurysm. Urinoma was diagnosed preoperatively by contrast-enhanced computed tomography. The patient was successfully treated by percutaneous nephrostomy and ureteral double J stent placement followed by staged operative repair.

The utility of cyclosporine weaning in renal transplantation

Abrupt conversion of cyclosporine immunosuppression to conventional treatment with azathioprine and prednisone avoids long-term cyclosporine nephrotoxicity, albeit at the cost of a 20% to 40% rejection rate. The authors investigated the benefits and risks of a cyclosporine weaning protocol in 24 cadaveric and 9 live donor kidney recipients treated with a sequential quadruple immunosuppressive protocol. In cadaver kidney recipients, slow tapering of cyclosporine resulted in a 19% (p less than 0.001) improvement in the glomerular filtration rate, as estimated by the inverse ratio of the plasma creatinine concentration. Cadaver kidney recipients were stratified according to graft function (GFR ratio greater than 0.76, less than 0.76) at the of cyclosporine discontinuation. In 12 patients with well-functioning grafts, a 24% improvement was observed, whereas in 12 patients with poor graft function, the gain was limited to 13%. Patients with limited graft function tended to have more acute rejection episodes before cyclosporine weaning (0.92 +/- 0.64 versus 0.42 +/- 0.64, not significant). When the 24 cadaver kidney recipients were stratified according to onset of graft function after transplantation (days to plasma creatinine of 250 mumol/L), need for dialysis, panel reactive antibodies (PRA), and duration of cyclosporine treatment, no significant differences in graft function were observed at the onset or end of cyclosporine weaning. Acute graft rejection before cyclosporine weaning was the only variable associated with a significantly lower estimated glomerular filtration rate ratio at the end of cyclosporine treatment (0.83 +/- 0.11 versus 0.67 +/- 0.16, p less than 0.01). Weaning of cyclosporine was associated with a minimal risk of acute graft rejection. A single patient with stable graft function at the onset of the weaning process experienced an acute but reversible rejection episode 2 months after cyclosporine was discontinued. In summary, gradual weaning of cyclosporine improves graft function, and eliminates the excessive risk of acute graft rejection without the need for additional corticosteroid treatment.

Intraoperative duplex study of internal thoracic artery spasm during coronary bypass

In this article, we document flow disturbance due to internal thoracic artery spasm (ITA) in a patient undergoing minimally invasive coronary artery grafting. We used intraoperative duplex scanning. Application of systemic vasodilators resulted in rapid improvement of ITA flow, as demonstrated by serial duplex examinations.

The utility of selective screening for carotid stenosis in cardiac surgery patients

PURPOSE

To determine if any of 8 categorical clinical variables can be used to select patients and improve the yield of a screening program for severe carotid stenosis (> or = 80%) in elective cardiac surgery patients.

METHODS

A prospective cohort analysis of 200 consecutive patients prior to elective cardiac surgery for the following variables: age, gender, smoking carotid bruit, peripheral vascular disease, hyperlipidaemia, previous neurologic symptoms and diabetes mellitus. All patients were subsequently screened with carotid duplex scanning for the presence of severe carotid stenosis. Positive scans were confirmed by angiography.

RESULTS

Sixteen patients (8%) were identified with severe carotid stenosis. Univariate analysis identified three variables that increase risk for carotid stenosis: carotid bruit (relative risk (RR)=16.4, 5.4-57.6 95% confidence interval, p<0.001), neurological history (RR=10.3, 3.9-23.2, p<0.001) and peripheral vascular disease (RR=5.3, 1.9-14.9, p<0.001). Stepwise logistic regression analysis identified previous neurologic history and carotid bruit as independent predictors of stenosis. If screening for carotid stenosis was limited to patients with these two variables, then 37 (18.5% of total) patients would have been screened. Fourteen of these 37 (37.8%) had a severe carotid stenosis. Two patients with stenosis (12.5% of those with carotid stenosis, 1% of total patient population) would not have been screened.

CONCLUSIONS

Clinical variables can be used to improve the yield of a preoperative screening program for carotid stenosis.

Recurrent pancreatitis associated with in vitro fertilization

BACKGROUND

We report the possible association between in vitro fertilization (IVF) and recurrent acute pancreatitis.

CASE

A patient developed acute pancreatitis during each of two cycles of IVF. On a spontaneous cycle, serum triglycerides were as follows: early follicular phase 2.34 mmol/L, mid-follicular phase 4.17 mmol/L, and late follicular phase 6.6 mmol/L. During an episode of acute pancreatitis, the serum triglyceride level was 38.45 mmol/L.

CONCLUSION

Acute pancreatitis may occur in patients with a family or personal history of hypertriglyceridemia who are candidates for IVF.

Noninvasive blood flow tests in vascular disease

Noninvasive testing is now routine for assessing vascular conditions. Many noninvasive tests are available for obtaining physiologic and anatomic information that is both precise and reproducible. This paper discusses noninvasive testing with plethysmography, Doppler ultrasonography, and duplex scanning for carotid artery occlusive disease, deep venous thrombosis, and peripheral arterial occlusive disease.

Care of the gut in the surgical intensive care unit: fact or fashion?

The traditional approach to the care of the gastrointestinal tract in the intensive care unit has been one of neglect. However, recent evidence has linked enteric flora to the generation of clinical sepsis in the absence of other infectious foci. The role of the bowel as an efficient barrier to the invasion of its own flora is addressed in this paper. A variety of insults disrupt the integrity of the barrier function of the gut, allowing the entry of bowel organisms or endotoxins, or both, into the portal and systemic circulatory systems. In animal and early clinical studies, a number of interventions, aimed at altering the enteric flora and enhancing the bowel's barrier function, have been shown to modulate the host's resistance to different insults and may even improve clinical outcome. Such interventions include maintenance of enteral feeding, glutamine supplementation of hyperalimentation solutions and selective bacterial decontamination of the bowel.

Endarterectomy versus angioplasty in the treatment of localized stenosis of the abdominal aorta

OBJECTIVE

To compare the outcome after aortoiliac endarterectomy and percutaneous transluminal angioplasty (PTA) of the aorta for localized stenosis of the lower abdominal aorta.

DESIGN

Chart review of patients treated over a 5-year period.

SETTING

A university centre.

PATIENTS

Sixteen women, all of whom were smokers; 5 had hyperlipidemia, 4 had evidence of coronary artery disease, 3 were hypertensive, and 1 was diabetic.

INTERVENTIONS

Aortoiliac endarterectomy (eight women) and PTA (eight women).

MAIN OUTCOME MEASURES

Ankle-brachial pressure index (ABI), degree of claudication and clinical outcome.

RESULTS

Angiography showed localized stenosis of the lower aorta in all patients, aortic hypoplasia in nine patients and associated common iliac disease in seven. None of the eight patients managed by aortoiliac endarterectomy had complications or died. All were free of claudication at a mean follow-up of 29 months and had durable improvement in their ABI: mean ABI preoperatively was 0.69 (standard deviation [SD] 0.1) and postoperatively was 1.06 (SD 0.07). Of the eight patients treated by PTA, only one had partial dilatation; another had a subintimal tear with worsening symptoms and a fall in ABI, requiring surgery within 18 months. The remaining six were symptom free after a mean follow-up of 13.4 months. Aortic PTA resulted in improvement of the ABI: mean ABI before PTA was 0.69 (SD 0.19) and after PTA was 1.06 (SD 0.15).

CONCLUSIONS

Endarterectomy is a safe and effective method of treating occlusive disease limited to the distal aorta. PTA appears to be less reliable. However, it is recommended as the initial treatment of choice in patients with angiographically suitable lesions because it is less invasive.