Adiposopathy and bariatric surgery: is 'sick fat' a surgical disease?

OBJECTIVE

To review how bariatric surgery in obese patients may effectively treat adiposopathy (pathogenic adipose tissue or 'sick fat'), and to provide clinicians a rationale as to why bariatric surgery is a potential treatment option for overweight patients with type 2 diabetes, hypertension, and dyslipidaemia.

METHODS

A group of clinicians, researchers, and surgeons, all with a background in treating obesity and the adverse metabolic consequences of excessive body fat, reviewed the medical literature regarding the improvement in metabolic disease with bariatric surgery.

RESULTS

Bariatric surgery improves metabolic disease through multiple, likely interrelated mechanisms including: (i) initial acute fasting and diminished caloric intake inherent with many gastrointestinal surgical procedures; (ii) favourable alterations in gastrointestinal endocrine and immune responses, especially with bariatric surgeries that reroute nutrient gastrointestinal delivery such as gastric bypass procedures; and (iii) a decrease in adipose tissue mass. Regarding adipose tissue mass, during positive caloric balance, impaired adipogenesis (resulting in limitations in adipocyte number or size) and visceral adiposity are anatomic manifestations of pathogenic adipose tissue (adiposopathy). This may cause adverse adipose tissue endocrine and immune responses that lead to metabolic disease. A decrease in adipocyte size and decrease in visceral adiposity, as often occurs with bariatric surgery, may effectively improve adiposopathy, and thus effectively treat metabolic disease. It is the relationship between bariatric surgery and its effects upon pathogenic adipose tissue that is the focus of this discussion.

CONCLUSIONS

In selective obese patients with metabolic disease who are refractory to medical management, adiposopathy is a surgical disease.

Longitudinal changes in pancreatic and adipocyte hormones following Roux-en-Y gastric bypass surgery

AIMS/HYPOTHESIS

Bariatric surgery is an effective treatment for severe obesity, as in addition to dramatic weight loss, co-morbidities such as type 2 diabetes are frequently resolved. Although altered gastrointestinal peptide hormone secretion and its relationship with post-surgical improvements in insulin sensitivity has been studied, much less is known about long-term changes in pancreatic and adipose tissue-derived hormones. Our objective was to conduct a comprehensive longitudinal investigation of the endocrine changes following Roux-en-Y gastric bypass surgery (RYGBP), focusing on pancreatic and adipocyte hormones and systemic markers of inflammation.

METHODS

Nineteen severely obese women (BMI 45.6 +/- 1.6 kg/m(2)) were studied prior to RYGBP, and at 1, 3, 6, and 12 months after RYGBP. Body composition was assessed before surgery and at 1 and 12 months.

RESULTS

Pre-surgical adiposity was correlated with circulating adipocyte hormones (leptin, visfatin) and inflammatory molecules (IL-6, high sensitivity C-reactive protein [hsCRP], monocyte chemoattractant protein-1). As expected, RYGBP reduced fat mass and fasting insulin and glucose concentrations. In addition, reductions of fasting pancreatic polypeptide (PP) and glucagon concentrations were observed at 1 and 3 months, respectively. In the 12 months following RYGBP, concentrations of most adipocyte hormones (leptin, acylation-stimulating hormone and visfatin, but not retinol-binding hormone-4) and inflammatory molecules (IL-6, hsCRP and soluble intracellular adhesion molecule-1) were significantly reduced. Reductions of insulin resistance (measured by homeostasis model assessment of insulin resistance) were independently associated with changes of glucagon, visfatin and PP. Pre-surgical HMW adiponectin concentrations independently predicted losses of body weight and fat mass.

CONCLUSIONS/INTERPRETATION

These results suggest that pancreatic and adipocyte hormones may contribute to the long-term resolution of insulin resistance after RYGBP.

Esophageal motility disorders after gastric banding

The long-term effects of gastric banding on esophageal function are not well described. This report describes a 28-year-old woman who developed signs and symptoms of abnormal esophageal motility and lower esophageal sphincter hypotension after gastric banding for morbid obesity. The current literature addressing the effects of gastric banding on esophageal function in light of this case report is discussed.

Serum leptin levels, hepatic leptin receptor transcription, and clinical predictors of non-alcoholic steatohepatitis in obese bariatric surgery patients

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is a major cause of liver disease in morbidly obese patients. Clinical predictors of NASH remain elusive, as do molecular mechanisms of pathogenesis.

METHODS

A series of 35 morbidly obese patients undergoing bariatric surgery had a liver biopsy performed for standard histologic analysis. In addition, RNA was obtained from liver tissue and analyzed for leptin receptor gene expression. Regression analysis was used to correlate clinical variables, including serum leptin levels and hepatic leptin receptor gene expression, with the presence of histologically confirmed NASH.

RESULTS

Of the 35 subjects enrolled, 29% had steatosis only, 60% had NASH, and 11% had normal liver histology. Among the clinical variables studied, only diabetes mellitus was an independent predictor of NASH. There was a trend toward lower levels of mRNA encoding the long form of the leptin receptor in hepatic tissue from patients with NASH compared to those with steatosis only.

CONCLUSIONS

Diabetes mellitus is associated with an increased risk of NASH in obese patients. Downregulation of hepatic leptin receptor may play a role in the pathogenesis of NASH.

Circulating concentrations of high-molecular-weight adiponectin are increased following Roux-en-Y gastric bypass surgery

AIMS/HYPOTHESIS

In addition to weight loss, bariatric surgery for severe obesity dramatically alleviates insulin resistance. In this study, we investigated whether circulating concentrations of the high-molecular-weight (HMW) form of adiponectin are increased following gastric bypass surgery. The HMW form is implicated as the multimer responsible for adiponectin's hepatic insulin-sensitising actions.

SUBJECTS AND METHODS

We studied 19 women who were undergoing Roux-en-Y gastric bypass surgery. Studies were conducted prior to, and 1 and 12 months after surgery.

RESULTS

One month after surgery, total plasma adiponectin concentrations were unchanged. Nevertheless, increases in both HMW (by 40+/-15%, p=0.006) and the proportion of adiponectin in the HMW form (from 40+/-2 to 50+/-2%, p<0.0001) were observed. At 12 months, total and HMW adiponectin concentrations were increased by 58+/-8% and 118+/-21%, respectively (both p<0.001). The majority (80%) of the increase of total adiponectin was due to an increase of the HMW form. After adjustment for covariates, increases of HMW and total adiponectin at 12 months were correlated with the decrease of fat mass (HMW, p=0.0076; total, p=0.0302). In subjects with improved insulin sensitivity at 12 months after surgery (n=18), the increase of HMW, but not that of total adiponectin, predicted the relative decrease of insulin resistance (HMW: p=0.0044; total: p=0.0775, after adjustment for covariates).

CONCLUSIONS/INTERPRETATION

These data suggest that the reduction of fat mass following gastric bypass surgery is an important determinant of the increase of HMW adiponectin concentrations, which in turn is associated with and may contribute to the resulting improvement of insulin sensitivity.

The SAGES Bariatric Surgery Outcome Initiative

BACKGROUND

The recent initiative for identifying centers of excellence in bariatric surgery calls for documentation of surgical outcomes. The SAGES Outcomes Initiative is a national database introduced in 1999 as a method for surgeons to accumulate and compare their data with summary national data. A bariatric-specific dataset was established later in 2001. The aim of this study was to compare the outcomes of bariatric surgery from the Society of American Gastrointestinal Endoscopic Surgeons' (SAGES) bariatric database with data derived from a national administrative database of academic centers.

METHODS

Between 2001 and 2004, 24 surgeons with 1,954 patients participated in the SAGES Bariatric Outcome Initiative, and 97 institutions with 42,847 patients participated in the University HealthSystem Consortium (UHC) database. Only 7 of the 24 surgeons participating in the SAGES Bariatric Outcome Initiative submitted more than 50 cases. The main outcome measures included demographics, comorbidities, type of bariatric procedure, operative time, length of hospital stay, short- and long-term complications, mortality, and weight loss.

RESULTS

Both datasets were comparable for gender. Roux-en-Y gastric bypass had been performed for 88% of the patients in the SAGES database and 96% of the patients in the UHC database. Associated comorbidities were similar between the two groups except for a higher rate of hyperlipidemia for the patients in the SAGES database. The SAGES database contains more bariatric-specific information such as body mass index, operative time, blood loss, bariatric-specific complications, long-term complications, and weight loss data than the UHC database. According to the available data, no statistically significant differences exist between the two datasets in terms of perioperative complications and mortality.

CONCLUSIONS

The SAGES Bariatric Outcome Initiative provides valuable bariatric-specific data not currently available in an administrative database that may be useful for benchmarking purposes. However, this database is currently underutilized.

Robot-assisted laparoscopic Roux-en-Y gastric bypass

BACKGROUND

Robotic surgery promises to extend the capabilities of the minimally invasive surgeon. The aim of this study was to examine the feasibility of robotic surgery in the setting of laparoscopic gastric bypass.

METHODS

The Zeus robotic surgical system was used in 50 laparoscopic gastric bypass procedures. The learning curve was staged to add complexity to the robotic tasks as experience grew. Robotic setup time, robotic operative time, total operative time, and operative outcomes were tracked prospectively.

RESULTS

We observed a significant decrease in the robotic setup time. Our robotic learning curve demonstrated decreased operative time, even as more complex tasks were accomplished. Total operative time also decreased significantly over the series. There were no complications in our series that could be attributed to the robotic technique.

CONCLUSIONS

Robot-assisted laparoscopic Roux-en-Y gastric bypass is safe. The steadiness and extra degrees of freedom of surgical robotic systems may improve the accuracy of laparoscopic tasks. The learning curve for robot-assisted laparoscopic Roux-en-Y gastric bypass is significant but manageable.

Effects of pneumoperitoneum on intraoperative pulmonary mechanics and gas exchange during laparoscopic gastric bypass

BACKGROUND

Hypercarbia and elevated intraabdominal pressure resulting from carbon dioxide (CO2) pneumoperitoneum can adversely affect respiratory mechanics. This study examined the changes in mechanical ventilation, CO2 homeostasis, and pulmonary gas exchange in morbidly obese patients undergoing a laparoscopic or open gastric bypass (GBP) procedure.

METHODS

In this study, 58 patients with a body mass index (BMI) of 40 to 60 kg/m2 were randomly allocated to laparoscopic ( n = 31) or open ( n = 27) GBP. Minute ventilation was adjusted to maintain a low normal arterial partial pressure of CO2 (PaCO2), low normal end-tidal partial pressure of CO2 (ETCO2), and low airway pressure. Respiratory compliance, ETCO2, peak inspiratory pressure (PIP), total exhaled CO2 per minute (VCO2), and pulse oximetry (SO2) were measured at 30-min intervals. The acid-base balance was determined by arterial blood gas analysis at 1-h intervals. The pulmonary gas exchange was evaluated by calculation of the alveolar dead space-to-tidal volume ratio (V(Dalv)/V(T)) and alveolar-arterial oxygen gradient (PAO2-PaO2).

RESULTS

The two groups were similar in age, gender, and BMI. As compared with open GBP, laparoscopic GBP resulted in higher ETCO2, PIP, and VCO2, and a lower respiratory compliance. Arterial blood gas analysis demonstrated higher PaCO2 and lower pH during laparoscopic GBP than during open GBP ( p < 0.05). The V(Dalv)/V(T) ratio and PAO2-PaO2 gradient did not change significantly during laparoscopic GBP. Intraoperative oxygen desaturation (SO2 < 90%) did not develop in any of the patients in either group.

CONCLUSIONS

Laparoscopic GBP alters intraoperative pulmonary mechanics and acid-base balance but does not significantly affect pulmonary oxygen exchange. Changes in pulmonary mechanics are well tolerated in morbidly obese patients when proper ventilator adjustments are maintained.

Duplex ultrasound assessment of femoral venous flow during laparoscopic and open gastric bypass

BACKGROUND

Pneumoperitoneum (PP) and the reverse Trendelenburg (RT) position have been shown to decrease femoral blood flow, resulting in venous stasis. However the effects of PP and RT on femoral venous flow have not been evaluated in morbidly obese patients undergoing laparoscopic gastric bypass (GBP). We analyzed the effects of PP and RT on peak systolic velocity and the cross-sectional area of the femoral vein during laparoscopic and open GBP. We further examined the efficacy of intermittent sequential compression devices in reversing the reduction of femoral peak systolic velocity.

METHODS

Thirty patients with a body mass index (BMI) of 40-60 were randomly allocated to under go either laparoscopic (n = 14) or open (n = 16) GBP. A duplex ultrasound examination of the femoral vein was performed at baseline, during PP and combined PP and RT in the laparoscopic group, and at baseline and during RT in the open group. The ultrasound exam was performed first without the use of sequential compression devices and then with the sequential compression devices inflated to 45 mmHg.

RESULTS

The two groups were similar in age, sex, BMI, and calf and thigh circumferences. During laparoscopic GBP, PP resulted in a 43% decrease in peak systolic velocity and a 52% increase in the cross-sectional area of the femoral vein; the combination of PP and RT decreased peak systolic velocity to 57% of baseline and increased the femoral cross-sectional area to 121% of baseline. During laparoscopic GBP, the use of sequential compression devices during PP and RT partially reversed the reduction of femoral peak systolic velocity, but femoral peak systolic velocity was still lower than baseline by 38%. During open GBP, RT resulted in a 38% reduction in peak systolic velocity and a 69% increase in the cross-sectional area of the femoral vein; the use of sequential compression devices during RT partially reversed these changes by increasing femoral peak systolic velocity by 26%; however, it was still lower than baseline by 22%.

CONCLUSIONS

Pneumoperitoneum and reverse Trendelenburg position during laparoscopic and open GBP are independent factors for the development of venous stasis. Combining the reverse Trendelenburg position with pneumoperitoneum during laparoscopic GBP further reduces femoral peak systolic velocity and hence increases venous stasis. The use of sequential compression devices was partially effective in reversing the reduction of femoral peak systolic velocity, but it did not return femoral peak systolic velocity to baseline levels.

Effect of heated and humidified carbon dioxide gas on core temperature and postoperative pain: a randomized trial

BACKGROUND

Intraoperative hypothermia is a common event during laparoscopic operations. An external warming blanket has been shown to be effective in preventing hypothermia. It has now been proposed that using heated and humidified insufflation gas can prevent hypothermia and decrease postoperative pain. Therefore, we examined the extent of intraoperative hypothermia in patients undergoing laparoscopic Nissen fundoplication using an upper body warming blanket. We also attempted to determine whether using heated and humidified insufflation gas in addition to an external warming blanket would help to maintain intraoperative core temperature or decrease postoperative pain.

METHODS

Twenty patients were randomized to receive either standard carbon dioxide (CO2) gas (control, n = 10) or heated and humidified gas (heated and humidified, n = 10). After the induction of anesthesia, an external warming blanket was placed on all patients in both groups. Intraoperative core temperature and intraabdominal temperature were measured at 15-min intervals. Postoperative pain intensity was assessed using a visual analogue pain scale, and the amount of analgesic consumption was recorded. Volume of gas delivered, number of lens-fogging episodes, intraoperative urine output, and hemodynamic data were also recorded.

RESULTS

There was no significant difference between the two groups in age, length of operation, or volume of CO2 gas delivered. Compared with baseline value, mean core temperature increased by 0.4 degrees C in the heated and humidified group and by 0.3 degrees C in the control group at 1.5 h after surgical incision. Intraabdominal temperature increased by 0.2 degrees C in the heated and humidified group but decreased by 0.5 degrees C in the control group at 1.5 h after abdominal insufflation. There was no significant difference between the two groups in visual analog pain scale (5.4 +/- 1.6 control vs 4.5 +/- 2.8 heated and humidified), morphine consumed (27 +/- 26 mg control vs 32 +/- 19 mg heated and humidified), urine output, lens-fogging episodes, or hemodynamic parameters.

CONCLUSION

Heated and humidified gas, when used in addition to an external warming blanket, minimized the reduction of intraabdominal temperature but did not alter core temperature or reduce postoperative pain.

Current status of laparoscopic gastric bypass

Laparoscopic gastric bypass is emerging as a commonly performed procedure for the treatment of morbid obesity. This article discusses the indications for surgery, patient selection, surgical technique, management of complications, and outcomes of laparoscopic gastric bypass.

Cardiac function during laparoscopic vs open gastric bypass

BACKGROUND

Hypercarbia and increased intraabdominal pressure during prolonged pneumoperitoneum can adversely affect cardiac function. This study compared the intraoperative hemodynamics of morbidly obese patients during laparoscopic and open gastric bypass (GBP).

METHODS

Fifty-one patients with a body mass index (BMI) of 40-60 kg/m2 were randomly allocated to undergo laparoscopic (n = 25) or open (n = 26) GBP. Cardiac output (CO), mean pulmonary artery pressure (MPAP), pulmonary artery wedge pressure (PAWP), central venous pressure (CVP), heart rate (HR), and mean arterial pressure (MAP) were recorded at baseline, intraoperatively at 30-min intervals, and in the recovery room. Systemic vascular resistance (SVR) and stroke volume (SV) were also calculated.

RESULTS

The two groups were similar in terms of age, weight, and BMI. Operative time was longer in the laparoscopic than in the open group (p < 0.05). The HR and MAP increased significantly from baseline intraoperatively, but there was no significant difference between the two groups. In the laparoscopic group, CO was unchanged after insufflation, but it increased by 5.3% at 2.5 h compared to baseline and by 43% compared to baseline in the recovery room. In contrast, during open GBP, CO increased significantly by 25% after surgical incision and remained elevated throughout the operation. CO was higher during open GBP than during laparoscopic GBP at 0.5 h and at 1 h after surgical incision (p < 0.05). During laparoscopic GBP, CVP, MPAP, and SVR increased transiently and PAWP remained unchanged. During open GBP, CVP, MPAP, and PAWP decreased transiently and SVR remained unchanged. There was no significant difference in the amount of intraoperative fluid administered during laparoscopic (5.5 +/- 1.6 L) and open (5.6 +/- 1.7 L) GBP.

CONCLUSION

Prolonged pneumoperitoneum during laparoscopic gastric bypass does not impair cardiac function and is well tolerated by morbidly obese patients.

Transforming growth factor-beta1 inhibits macrophage cholesteryl ester accumulation induced by native and oxidized VLDL remnants

Transforming growth factor beta1 (TGF-beta1) is secreted by various cells, including macrophages, smooth muscle cells, and endothelial cells. TGF-beta1 is present in atherosclerotic lesions, but its role in regulating macrophage foam cell formation is not understood. Hypertriglyceridemic very low density lipoprotein (VLDL) remnants (VLDL-REMs) in their native or oxidized form will induce cholesteryl ester (CE) and triglyceride (TG) accumulation in macrophages. Therefore, we examined whether TGF-beta1 can modulate the macrophage uptake of native or oxidized VLDL-REMs (oxVLDL-REMs). Incubation of J774A.1 macrophages with VLDL-REMs and oxVLDL-REMs compared with control cells increased cellular CE (13- and 21-fold, respectively) and TG mass (21-and 18-fold, respectively). Preincubation with TGF-beta1 before incubation with VLDL-REMs or oxVLDL-REMs significantly decreased CE (73% and 54%, respectively) and TG mass (42% and 41%, respectively). TGF-beta1 inhibited the activity and expression of 2 key components needed for VLDL-REM uptake: lipoprotein lipase and low density lipoprotein receptor. TGF-beta1 inhibited CE mass induced by oxVLDL-REMs in part by decreasing the expression of scavenger receptor type AI/II and CD36. Furthermore, TGF-beta1 enhanced cholesterol efflux through upregulation of the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1. Thus, TGF-beta1 inhibits macrophage foam cell formation induced by VLDL-REMs or oxVLDL-REMs, which suggests an antiatherogenic role for this cytokine.

Evaluation of minimally invasive surgical staging for esophageal cancer

BACKGROUND

Conventional imaging studies (computed tomography and endoscopic esophageal ultrasonography) used for preoperative evaluation of patients with esophageal cancer can be inaccurate for detection of small metastatic deposits. We evaluated the efficacy of minimally invasive surgical (MIS) staging as an additional modality for evaluation of patients with esophageal cancer.

METHODS

Between December 1998 and February 2001, 33 patients with esophageal cancer were evaluated for surgical resection. Conventional imaging studies demonstrated operable disease in 31 patients and equivocal findings in 2 patients. All patients then underwent MIS staging (laparoscopy, bronchoscopy, and ultrasonography of the liver). We compared the results from surgical resection and MIS staging with those from conventional imaging.

RESULTS

MIS staging altered the treatment plan in 12 (36%) of 33 patients; MIS staging upstaged 10 patients with operable disease and downstaged 2 patients with equivocal findings. MIS staging accurately determined resectability in 97% of patients compared with 61% of patients staged by conventional imaging. The specificity and negative predictive value for detection of unsuspected metastatic disease in MIS staging were 100% and 96%, respectively, compared with 91% and 65%, respectively, for conventional imaging studies.

CONCLUSION

In addition to conventional imaging studies, MIS staging should be included routinely in the preoperative work-up of patients with esophageal cancer.

Evaluation of core temperature during laparoscopic and open gastric bypass

BACKGROUND

Intraoperative hypothermia is a common event during open and laparoscopic abdominal surgery. The aim of this study was to compare changes in core temperature between laparoscopic and open gastric bypass (GBP).

METHODS

101 patients with a body mass index (BMI) of 40-60 kg/m2 were randomly assigned to open (n = 50) or laparoscopic (n = 51) GBP. Anesthetic technique was similar for both groups. An external warming blanket and passive airway humidification were used intraoperatively. Core temperature was recorded at preanesthesia, at baseline (after induction) and at 30-min intervals; intra-abdominal temperature was additionally measured at 30-min intervals in a subset of 30 laparoscopic GBP patients. The number of patients who developed intraoperative and postoperative hypothermia (< 36 degrees C) was recorded. Length of operation for both groups and the amount of CO2 gas delivered during laparoscopic operations were also recorded.

RESULTS

There was no significant difference between groups with respect to age, gender, mean BMI, and amount of intravenous fluid administered. After induction of anesthesia, core temperature significantly decreased in both groups; 36% of patients in the open group and 37% of patients in the laparoscopic group developed hypothermia. This percentage increased to 46% in the open group and 41% in the laparoscopic group during the operation, and then decreased to 6% in the open group and 8% in the laparoscopic group in the recovery-room. Core temperature increased during the operative procedure to reach 36.5 +/- 0.6 degrees C in the open group and 36.3 +/- 0.5 degrees C in the laparoscopic group at 2.5 hours after surgical incision. Intra-abdominal temperature during laparoscopic GBP was significantly lower than core temperature at all measurement points (p < 0.05). Operative time was longer in the laparoscopic group than in the open group (232 +/- 43 vs 201 +/- 38 min, p < 0.01). Mean volume of gas delivered during laparoscopic GBP was 650 +/- 220 liters.

CONCLUSION

Perioperative hypothermia was a common event during both laparoscopic and open GBP. Despite a longer operative time, laparoscopic GBP did not increase the rate of intraoperative hypothermia when efforts were made to minimize intraoperative heat loss.

Laparoscopic versus open gastric bypass: a randomized study of outcomes, quality of life, and costs

OBJECTIVE

To compare outcomes, quality of life (QOL), and costs of laparoscopic and open gastric bypass (GBP).

SUMMARY BACKGROUND DATA

Laparoscopic GBP has been reported to be a safe and effective approach for the treatment of morbid obesity. The authors performed a prospective randomized trial to compare outcomes, QOL, and costs of laparoscopic GBP with those of open GBP.

METHODS

From May 1999 to March 2001, 155 patients with a body mass index (BMI) of 40 to 60 kg/m2 were randomly assigned to undergo laparoscopic (n = 79) or open (n = 76) GBP. The two groups were similar in age, sex ratio, mean BMI, and comorbidities. Main outcome measures included operative time, estimated blood loss, length of hospital stay, operative complications, percentage of excess body weight loss, and time to return to activities of daily living and work. Changes in QOL were assessed using the SF-36 Health Survey and the bariatric analysis of reporting outcome system (BAROS). Operative and hospital costs of the two operations were also compared.

RESULTS

There were no deaths in either group. Mean operative time was longer for laparoscopic GBP than for open GBP, but operative blood loss was less. Two (2.5%) of the 79 patients in the laparoscopic group required conversion to laparotomy. Median length of hospital stay was shorter for laparoscopic GBP patients (3 vs 4 days). The rate of postoperative anastomotic leak was similar between groups. Wound-related complications such as infection (10.5 vs 1.3%) and incisional hernia (7.9 vs 0%) were more common after open GBP; late anastomotic stricture was less frequent after open GBP (2.6 vs 11.4%). Time to return to activities of daily living and work were shorter after laparoscopic GBP than after open GBP. Weight loss at 1 year was similar between groups. Preoperative SF-36 scores were similar between groups; however, at 1 month after surgery, laparoscopic patients had better physical conditioning, social functioning, general health, and less body pain than open GBP patients. At 6 months, the BAROS outcome was classified as good or better in 97% of laparoscopic GBP patients compared with 82% of open GBP patients. Operative costs were higher for laparoscopic GBP patients, but hospital costs were lower.

CONCLUSIONS

Laparoscopic GBP is a safe and cost-effective alternative to open GBP. Despite a longer operative time, patients undergoing laparoscopic GBP benefited from less blood loss, a shorter hospital stay, and faster convalescence. Laparoscopic GBP patients had comparable weight loss at 1 year but a more rapid improvement in QOL than open GBP patients. The higher initial operative costs for laparoscopic GBP were adequately offset by the lower hospital costs.

Evaluation of intra-abdominal pressure after laparoscopic and open gastric bypass

BACKGROUND

Increased intra-abdominal pressure (IAP) postoperatively can adversely affect cardiovascular, pulmonary, and renal function. In this prospective, randomized trial, we compared the IAP in morbidly obese patients after laparoscopic and open gastric bypass (GBP) surgery.

METHODS

64 patients with a body mass index of 40 to 60 kg/m2 were randomized to undergo laparoscopic or open GBP. IAPs were obtained at baseline (after induction of anesthesia), immediately after the operation, and on post-operative day (POD) 1, 2, and 3. Intraoperative and postoperative fluid requirements, urine output, and creatinine clearance were recorded.

RESULTS

Demographics of the two groups were similar. IAP increased from baseline immediately after laparoscopic and open GBP (p < 0.05). IAP returned to baseline by POD 2 after laparoscopic GBP but remained elevated through POD 3 after open GBP. In fact, IAP was lower after laparoscopic GBP than after open GBP on POD 1, 2 and 3 (p < 0.05). The amount of intraoperative IV fluid was similar between groups, but laparoscopic GBP required less IV fluid and facilitated higher urine output postoperatively than open GBP. There was no significant difference in creatinine clearance between groups.

CONCLUSIONS

Laparoscopic GBP resulted in significantly lower IAP, less postoperative fluid required, and greater postoperative urine output than open GBP.

Increased transplantation of kidneys with multiple renal arteries in the laparoscopic live donor nephrectomy era: surgical technique and surgical and nonsurgical donor and recipient outcomes

BACKGROUND

For anatomical and technical reasons, many transplant centers restrict laparoscopic live donor nephrectomy (in contrast with open live donor nephrectomy) to left kidneys.

HYPOTHESIS

This change in surgical practice increases procurement and transplantation rates of live donor kidneys with multiple renal arteries (RAs), without affecting donor and recipient outcomes.

DESIGN AND SETTING

Retrospective review at an academic tertiary care referral center comparing laparoscopically procured single vs multiple-RA kidney grafts (April 1997 to October 2000).

PATIENTS

Seventy-nine consecutive left laparoscopic live kidney donors and 78 transplant recipients.

MAIN OUTCOME MEASURES

Donor and recipient complications and postoperative length of stay; cold and warm ischemia time; operating time; short-term and long-term graft function; and survival.

RESULTS

We noted multiple RAs in 21 (27%) of all kidneys. The proportion of donors with 1 or more perioperative complications was 19% in the single-RA group vs 10% in the multiple-RA group (P was not significant). For the recipients, we noted no significant differences between groups with respect to surgical complications, quality of early and late graft function, rejection rates, graft losses (all immunologic), and graft survival. Cold and warm ischemia time and length of stay were similar for donors and recipients in both groups. Median operating times were significantly longer for the multiple-RA vs single-RA group (difference, 41 minutes for donors and 45 minutes for recipients; P<.02).

CONCLUSIONS

While the introduction of laparoscopic live donor nephrectomy has significantly increased the number of grafts with multiple RAs (compared with historical open controls), this change in practice is safe for both donors and recipients from a patient outcome-based perspective. However, from an economic perspective, the longer operating time associated with multiple-RA grafts provides strong added rationale for optimization of surgical instruments and techniques to make right-sided laparoscopic nephrectomy a routine intervention.

Systemic coagulation and fibrinolysis after laparoscopic and open gastric bypass

HYPOTHESIS

Laparoscopic gastric bypass (GBP) induces a postoperative hypercoagulable state that is similar or reduced compared with open GBP.

SETTING

University hospital.

PATIENTS

Between May 1999 and June 2000, 70 patients were randomly assigned to laparoscopic (n = 36) or open (n = 34) GBP. Deep venous thrombosis (DVT) prophylaxis consisted of antiembolism stockings and sequential pneumatic compression devices.

MAIN OUTCOME MEASURES

Plasminogen, thrombin-antithrombin complex (TAT), prothrombin fragment 1.2 (F1.2), fibrinogen, D-dimer, antithrombin III (AT), and protein C levels were measured at baseline and at 1, 24, 48, and 72 hours postoperatively. A venous duplex examination of both lower extremities was performed preoperatively and between the third and fifth day postoperatively.

RESULTS

The 2 groups were similar in age, weight, and body mass index. Plasminogen levels decreased, and TAT, F1.2, and fibrinogen levels increased after laparoscopic and open GBP. There was no significant difference in these levels between groups. D-dimer levels increased in both groups, but the levels were significantly higher after open GBP than after laparoscopic GBP (P<.01). Antithrombin III and protein C levels decreased in both groups. The reduction of AT (at 1 hour) and protein C (at 72 hours) was significantly less after laparoscopic GBP than after open GBP (P<.05). Postoperative venous duplex examination revealed DVT in 1 (2.9%) of 34 patients after open GBP but in none of 36 patients after laparoscopic GBP. One patient developed pulmonary embolism after open GBP.

CONCLUSIONS

Laparoscopic GBP induces a hypercoagulable state similar to that of open GBP. Our findings suggest that DVT prophylaxis should be used during laparoscopic GBP as in open GBP.

Quadriceps muscle function and fatigue in women with Addison's disease

In nine patients with Addison's disease (mean +/- SE: 51 +/- 2 years) receiving conventional steroid treatment, and nine age-matched healthy controls (56 +/- 2 years), we investigated maximum voluntary quadriceps force (MVC) and contractile properties evoked with stimulation and central activation both at rest and during a submaximal intermittent fatigue task. The MVC was similar (-3%), but twitch tension (-27%) and central activation were significantly less (-7%), and tetanic half-relaxation time was approximately 40% slower in the patients. Twitch amplitudes were potentiated by 6% in the patients, but unchanged in the control group. The patients self-terminated a submaximal intermittent fatigue protocol (0.6 duty cycle) at approximately 5 +/- 1 min, whereas the controls stopped when they lost 50% of MVC force ( approximately 10 +/- 1 min). Force loss was similar between groups over the first 5 min of the fatigue task. In the patient group, maximal and submaximal relative integrated electromyogram (IEMG) increased significantly in the first minute of fatigue and remained elevated, whereas the controls exhibited a gradual increase in submaximal IEMG with little change in maximal IEMG. These results indicate that conventionally treated Addison's patients have similar MVC strength, but altered contractile properties and decreased endurance compared with controls.

Lecithin:cholesterol acyl transferase G30S: association with atherosclerosis, hypoalphalipoproteinemia and reduced in vivo enzyme activity

OBJECTIVES

A 69 yr old male was referred for assessment of a very low plasma HDL cholesterol and apolipoprotein AI concentration. At age 65, he had undergone triple vessel coronary bypass graft surgery. He had a strong family history of early coronary heart disease. We analyzed the molecular basis of his clinical and biochemical abnormalities.

DESIGN AND METHODS

We used DNA sequencing to determine whether mutations in LCAT were present. We also evaluated plasma biochemistry and LCAT activity.

RESULTS

DNA sequencing revealed that the patient was a heterozygote for the G30S mutation in the gene encoding lecithin:cholesteol acyl transferase (LCAT). His plasma was found to have half-normal LCAT activity.

CONCLUSIONS

The findings in this patient suggest that rare dysfunctional mutations in candidate genes, such as LCAT, can contribute to the spectrum of patients ascertained because of low HDL cholesterol.

A Prospective Evaluation of Intracorporeal Laparoscopic Small Bowel Anastomosis during Gastric Bypass

BACKGROUND

We evaluated the safety and feasibility of performing a laparoscopic intracorporeal end-to-side small bowel anastomosis using a stapling technique as part of a Roux-en-Y gastric bypass operation (RYGBP).

METHODS

80 consecutive patients who underwent RYGBP with laparoscopic jejunojejunostomy were evaluated. Operative time and intraoperative and postoperative complications directly related to the jejunojejunostomy anastomosis were recorded.

RESULTS

All 80 laparoscopic jejunojejunostomy procedures were successfully performed without conversion to laparotomy. Mean operative time was longer for the first 40 laparoscopic RYGBP than for the last 40 RYGBP (32+/-18 min vs 21+/-14 min, respectively, p<0.05). Intraoperative complications were staple-line bleeding (2 patients) and narrowing of the anastomosis (1 patient). Postoperative complications were four small bowel obstructions: technical narrowing at jejunojejunostomy site (2 patients), angulation of the afferent limb (1 patient), and food impaction at the jejunojejunostomy anastomosis (1 patient). These four patients underwent successful laparoscopic re-exploration and creation of another jejunojejunostomy proximal to the original anastomosis. There were no small bowel anastomotic leaks. The median time to resuming oral diet was 2 days.

CONCLUSIONS

Laparoscopic jejunojejunostomy as part of the RYGBP operation is a safe and technically feasible procedure. Postoperative small bowel obstruction is a potential complication, which can be prevented by avoiding technical narrowing of the afferent limb.

Comparison of pulmonary function and postoperative pain after laparoscopic versus open gastric bypass: a randomized trial

BACKGROUND

Impairment of pulmonary function is common after upper abdominal operations. The purpose of this study was to compare postoperative pulmonary function and analgesic requirements in patients undergoing either laparoscopic or open Roux-en-Y gastric bypass (GBP).

STUDY DESIGN

Seventy patients with a body mass index of 40 to 60 kg/m2 were randomly assigned to undergo laparoscopic (n = 36) or open (n = 34) GBP. The two groups were similar in age, gender, body mass index, pulmonary history, and baseline pulmonary function. Pulmonary function studies were performed preoperatively and on postoperative days 1, 2, 3, and 7. Oxygen saturation and chest radiographs were performed on both groups preoperatively and on postoperative day 1. Postoperative pain was evaluated using a visual analog scale and the amount of narcotic consumed was recorded. Data are presented as mean +/- standard deviation.

RESULTS

Laparoscopic GBP patients had significantly less impairment of pulmonary function than open GBP patients on the first three postoperative days (p < 0.05). By the 7th postoperative day, all pulmonary function parameters in the laparoscopic GBP group had returned to within preoperative levels, but only one parameter (peak expiratory flow) had returned to preoperative levels in the open GBP group. On the first postoperative day, laparoscopic GBP patients used less morphine than open GBP patients (46 +/- 31 mg versus 76 +/- 39 mg, respectively, p < 0.001), and visual analog scale pain scores at rest and during mobilization were lower after laparoscopic GBP than after open GBP (p < 0.05). Fewer patients after laparoscopic GBP than after open GBP developed hypoxemia (31% versus 76%, p < 0.001) and segmental atelectasis (6% versus 55%, p = 0.003).

CONCLUSION

Laparoscopic gastric bypass resulted in less postoperative suppression of pulmonary function, decreased pain, improved oxygenation, and less atelectasis than open gastric bypass.

Cancer of the colon and rectum in California: trends in incidence by race/ethnicity, stage, and subsite

BACKGROUND

Incidence and mortality from cancer of the colon and rectum have declined in recent years in the United States and California, but reasons for the decline are unknown.

METHODS

Age-adjusted site-specific and stage-specific incidence rates were calculated for approximately 9,000 cases of in situ cancer and 120,000 cases of invasive cancer of the colon and rectum diagnosed between 1988 and 1996 among California residents and reported to the California Cancer Registry. Trends in incidence over time were measured using the estimated annual percent change.

RESULTS

Among non-Hispanic whites there was a decline in all sites and stages, but the decrease was most pronounced for rates of in situ and regional/distant tumors in the rectum and sigmoid which declined by about 4 to 7% a year. For tumors in the proximal colon, the decrease was statistically significant only for regional/distant tumors which declined about 2% a year. Among blacks, there was an approximately 7% annual decline in the incidence of regional/distant tumors of the rectum in women and a nearly 3% a year decrease in regional/distant tumors of the proximal colon in men. The decline in rates for Hispanics and Asian/Pacific Islanders was smaller and less consistent than for non-Hispanic whites.

CONCLUSIONS

The results confirm a overall decline in all stages of cancer of the colon and rectum in California, particularly among non-Hispanic white men and women. The decrease was most pronounced for tumors in the rectum and sigmoid colon and may be attributable to screening.

Outcomes assessment and minimally invasive surgery: historical perspective and future directions

BACKGROUND

Outcomes assessment is being used increasingly to shape practice patterns in all areas of medicine. Although outcomes assessment is not a new concept, the widespread application of outcomes measurement for modifying practice is novel. Instead of focusing on results of interventions in highly controlled environments, outcomes studies usually report results as they occur in uncontrolled, real-world environments. Recently, the Society of American Gastrointestinal Endoscopic Surgeons (SAGES) has initiated a society-wide initiative to monitor outcomes in patients undergoing various laparoscopic operations.

METHODS

Pertinent literature is reviewed as it relates to outcomes assessment. The historical background underpinning the modern interest in outcomes is outlined. Definitions of terms useful for understanding outcomes research are given. The impact of outcomes assessment on minimally invasive surgery, both positive and negative, are examined. The SAGES outcome initiative is introduced.

CONCLUSIONS

Although outcomes studies usually do not provide information on the causes of observations made, they have gained in popularity because they provide information about patient perceptions of disease, disability, and treatment. Minimally invasive surgical procedures often are reported in terms of outcomes assessment because a controlled clinical trial was rendered impossible by early and widespread application of laparoscopic surgery. The SAGES outcomes initiative will provide the necessary tools for the participation of surgeons in the process of practice profiling.

Laparoscopic suturing evaluation among surgical residents

BACKGROUND

Laparoscopic suturing is an integral part of advanced laparoscopic surgery training. The objective of this study was to evaluate the performance and preference of surgical residents performing intracorporeal and extracorporeal knot-tying techniques using conventional and Endo Stitch instruments. The residents were also evaluated on their suturing techniques using conventional instruments, the Endo Stitch, and the Suture Assistant.

METHODS

Using an inanimate laparoscopic trainer model, 39 residents were evaluated as they performed laparoscopic knot tying exercises. Endpoints of the study were execution time and subjective preference of surgical residents with respect to the type of instrument used for knot tying. Forty-three residents were evaluated as they performed laparoscopic suturing exercises with three different types of suturing instruments using the same endpoints.

RESULTS

The intracorporeal technique was the preferred (89%) method of knot tying among surgical residents. The time for completion of laparoscopic suturing was significantly (P < 0.05) shorter with the Endo Stitch (114 +/- 64 s) than with the conventional instrument (206 +/- 107 s) or the Suture Assistant (151 +/- 70 s). Residents preferred the use of the Endo Stitch in all three categories for suturing, knot tying, and handling.

CONCLUSION

The Endo Stitch enhanced laparoscopic skills and was the preferred instrument for laparoscopic knot tying and suturing among surgical residents.

Comparison of minimally invasive esophagectomy with transthoracic and transhiatal esophagectomy

HYPOTHESIS

Minimally invasive esophagectomy can be performed as safely as conventional esophagectomy and has distinct perioperative outcome advantages.

DESIGN

A retrospective comparison of 3 methods of esophagectomy: minimally invasive, transthoracic, and blunt transhiatal.

SETTING

University medical center.

PATIENTS

Eighteen consecutive patients underwent combined thoracoscopic and laparoscopic esophagectomy from October 9, 1998, through January 19, 2000. These patients were compared with 16 patients who underwent transthoracic esophagectomy and 20 patients who underwent blunt transhiatal esophagectomy from June 1, 1993, through August 5, 1998.

MAIN OUTCOME MEASURES

Operative time, amount of blood loss, number of operative transfusions, length of intensive care and hospital stays, complications, and mortality.

RESULTS

Patients who had minimally invasive esophagectomy had shorter operative times, less blood loss, fewer transfusions, and shortened intensive care unit and hospital courses than patients who underwent transthoracic or blunt transhiatal esophagectomy. There was no significant difference in the incidence of anastomotic leak or respiratory complications among the 3 groups.

CONCLUSION

Minimally invasive esophagectomy is safe and provides clinical advantages compared with transthoracic and blunt transhiatal esophagectomy.

A comparison study of laparoscopic versus open gastric bypass for morbid obesity

BACKGROUND

Laparoscopic Roux-en-Y gastric bypass (GBP) has been previously described, but a comparative study between laparoscopic and open GBP has not been reported. The purpose of this study was to compare surgical outcomes oflaparoscopic GBP with those of open GBP for treatment of morbid obesity.

STUDY DESIGN

From August 1998 to September 1999, we prospectively collected outcome data on 35 patients with body-mass indices between 40 kg/m2 and 60 kg/m2 who underwent laparoscopic GBP. Demographics, operative data, perioperative complications, and weight losses were collected and compared with those obtained from a retrospective chart review of 35 patients with body-mass indices between 40 kg/m2 and 60 kg/m2 who underwent open GBP before August 1998.

RESULTS

Age, gender, preoperative body-mass index, preoperative comorbidity, and earlier abdominal surgery were similar in both groups. All laparoscopic operations were completed without conversion to laparotomy. Mean operative time, operative blood loss, length of intensive care stay, and length of hospital stay were significantly less after laparoscopic GBP than after open GBP (p<0.05). There was no 30-day mortality in either group. At 1-year followup, analysis of the percentage of excess body weight loss showed no significant difference between the two groups (p<0.05).

CONCLUSIONS

Laparoscopic Roux-en-Y gastric bypass is technically feasible and safe. Laparoscopic GBP confers the clinical benefits of laparoscopy and an initial weight loss similar to that of open GBP.

Effects of continuous conjugated estrogen and micronized progesterone therapy upon lipoprotein metabolism in postmenopausal women

The effects of continuously administering both conjugated equine estrogens (CEE) and micronized progesterone (MP) on the concentration, composition, production and catabolism of very low density (VLDL) and low density lipoproteins (LDL) have not previously been reported. The mechanism of the hormonally induced reductions of plasma LDL cholesterol of S(f) 0;-20 (mean 16%, P < 0.005) and LDL apoB (mean 6%, P < 0.025) were investigated by studying the kinetics of VLDL and LDL apolipoprotein (apo) B turnover after injecting autologous (131)I-labeled VLDL and (125)I-labeled LDL into each of the 6 moderately hypercholesterolemic postmenopausal subjects under control conditions and again in the fourth week of a 7-week course of therapy (0.625 mg/d of CEE + 200 mg/d of MP). The combined hormones significantly lowered plasma LDL apoB by increasing the mean fractional catabolic rate of LDL apoB by 20% (0. 32 vs. 0.27 pools/d, P < 0.03). Treatment also induced a significant increase in IDL production (6.3 vs. 3.7 mg/kg/d, P = 0.028). However, this did not result in an increase in LDL production because of an increase in IDL apoB direct catabolism (mean 102%, P = 0.033). VLDL kinetic parameters were unchanged and the concentrations of plasma total triglycerides (TG), VLDL-TG, VLDL-apoB did not rise as often seen with estrogen alone. Plasma HDL-cholesterol rose significantly (P < 0.02). Our major conclusion is that increased fractional catabolism of LDL underlies the LDL-lowering effect of the combined hormones.

Effect of intravascular volume expansion on renal function during prolonged CO2 pneumoperitoneum

OBJECTIVE

To evaluate whether intravascular volume expansion would improve renal blood flow and function during prolonged CO2 pneumoperitoneum.

SUMMARY BACKGROUND DATA

Although laparoscopic living donor nephrectomies have a considerably reduced risk of complications for the donors, significant concerns exist regarding procurement of a kidney in the altered physiologic environment of CO2 pneumoperitoneum. Recent studies have documented adverse effects of CO2 pneumoperitoneum on renal hemodynamics.

METHODS

Renal and systemic hemodynamics and renal histology were studied in a porcine CO2 pneumoperitoneum model. After placement of a pulmonary artery catheter, carotid arterial line, Foley catheter, and renal artery ultrasonic flow probe, CO2 pneumoperitoneum (15 mmHg) was maintained for 4 hours. Pigs were randomized into three intravascular fluid protocol groups: euvolemic (3 mLkg/hour isotonic crystalloid), hypervolemic (15 mL/kg/hour isotonic crystalloid), or hypertonic (3 mL/kg/hour isotonic crystalloid plus 1.2 mL/kg/hour 7.5% NaCl).

RESULTS

In the euvolemic group, prolonged CO2 pneumoperitoneum caused decreased renal blood flow, oliguria, and impaired creatinine clearance. Both isotonic and hypertonic volume expansions reversed the changes in renal blood flow and urine output, but impaired creatinine clearance persisted.

CONCLUSIONS

Intravascular volume expansion alleviates the effects of CO2 pneumoperitoneum on renal hemodynamics in a porcine model. Hypertonic saline (7.5% NaCl) solution may maximize renal blood flow in prolonged pneumoperitoneum, but it does not completely prevent renal dysfunction in this setting. This study suggests that routine intraoperative volume expansion is important during laparoscopic live donor nephrectomy.

Hypopharyngeal perforation during laparoscopic Roux-en-Y gastric bypass

Laparoscopic Roux-en-Y gastric bypass was recently introduced as an alternative surgical treatment for morbid obesity. The technique involves placement of a 21-mm anvil transorally down to the gastric pouch for creation of the gastroenterostomy anastomosis using an EEA stapler placed transabdominally. Esophageal injury is a theoretical concern with transoral manipulation of the anvil. The authors present a case of hypopharyngeal perforation after an attempted transoral insertion of an EEA anvil. The perforation was treated with neck exploration and drainage. We discuss the mechanism of injury and alternative method for placement of the gastric anvil.

Impact on postmenopausal symptoms of adding continuous C-21 versus C-19 progestin to estrogen

OBJECTIVE

To compare the effects of (i) continuous low dosage C-19 progestin (dl-norgestrel, NG) plus cyclical conjugated estrogen (CEE) versus (ii) continuous low dosage C-21 progestin [medroxyprogesterone acetate (MPA)] plus CEE on postmenopausal vaginal bleeding, mood and somatic, psychosomatic and psychological symptoms.

METHODS

Nine hypercholesterolemic postmenopausal women with intact uteri were randomly assigned in a prospective, double-blind, two-period cross-over study of CEE (25/28 days) plus either (i) NG, (0.05 mg/day) or (ii) MPA (2.5 mg/day) for 1 year and after an appropriate wash-out period were switched to the alternative regimen for another year. Four hysterectomized control subjects received the CEE only.

RESULTS

Administration of CEE + MPA versus CEE + NG resulted in a significantly higher percent of cycles which were free of vaginal bleeding (97 vs 85%), spotting (92 vs 79%) and either spotting or bleeding (92 vs 76%, P < 0.01). All three regimens significantly reduced the overall combined scores for postmenopausal somatic, psychosomatic and psychological symptoms (P < 0.05).

CONCLUSIONS

Vaginal bleeding and/or spotting were significantly less frequent with CEE + MPA versus CEE + NG. However, each of the three hormonal regimens improved mood and significantly reduced postmenopausal symptoms in comparison to untreated control values.

Laparoscopic Roux-en-Y gastric bypass for super/super obesity

Laparoscopic gastric bypass has been recently introduced as an alternative method to conventional open gastric bypass. This procedure has been generally limited to patients with a BMI <60 kg/m2 due to the possible technical limitations of the laparoscopic instruments. In this article, we present a patient with super/super obesity (61 kg/m2) who underwent Rouxen-Y gastric bypass using the laparoscopic approach.

Replacement of carbohydrate by protein in a conventional-fat diet reduces cholesterol and triglyceride concentrations in healthy normolipidemic subjects

OBJECTIVE

To determine the effect on plasma lipid profiles of replacement of dietary carbohydrate by low-fat, high-protein foods.

DESIGN

Cross-over randomized controlled trial.

PARTICIPANTS

Ten healthy, normolipidemic subjects (8 women and 2 men).

INTERVENTIONS

Subjects were randomly allocated to either a low-protein (12%) or high-protein (22%) weight-maintaining diet for 4 weeks and then switched to the alternate diet for 4 more weeks. The first 2 weeks of each diet served as an adjustment/washout period. Fat was maintained at 35% of energy, mean cholesterol intake at 230 mg per day and mean fibre intake at 24 g per day. Compliance was promoted by the use of written dietary protocols based on the food preferences of the subjects and weekly dietary consultation as required.

OUTCOME MEASURES

Mean plasma levels of total, very-low-density-lipoprotein (VLDL), low-density-lipoprotein (LDL), and high-density-lipoprotein (HDL) cholesterol, and of total and very-low-density-lipoprotein (VLDL) triglycerides. Satiety levels were self-rated on a 10-point scale.

RESULTS

Consumption of the high- versus the low-protein diet resulted in significant reductions in mean plasma levels of total cholesterol (3.8 v. 4.1 mmol/L, p < 0.05), VLDL cholesterol (0.20 v. 0.26 mmol/L, p < 0.02), LDL cholesterol (2.4 v. 2.6 mmol/L, p < 0.05), total triglycerides (0.69 v. 0.95 mmol/L, p < 0.005) and VLDL triglycerides (0.35 v. 0.57 mmol/L, p < 0.001), as well as in the ratio of total cholesterol to HDL cholesterol (3.1 v. 3.5, p < 0.01). A trend towards an increase in HDL cholesterol (1.26 v. 1.21 mmol/L, p = 0.30) was observed but was not statistically significant. Satiety levels tended to be higher among those eating the high-protein diet (6.1 v. 5.4, p = 0.073).

CONCLUSIONS

Moderate replacement of dietary carbohydrate with low-fat, high-protein foods in a diet containing a conventional level of fat significantly improved plasma lipoprotein cardiovascular risk profiles in healthy normolipidemic subjects.

Endoscopy during laparoscopy. Reduced postprocedural bowel distention with intraluminal CO2 insufflation

BACKGROUND

Intraluminal endoscopy during laparoscopy can substitute for manual palpation in defining anatomy and pathology, but a potential problem is the persistent bowel distention associated with intraluminal air insufflation.

METHODS

To compare the rates of intraluminal absorption, a 30-cm segment of small bowel with an intact vascular supply was insufflated with either air or CO2 during CO2 pneumoperitoneum. Intraluminal pressures and bowel circumferences were monitored after the insufflation was stopped. To study the metabolic and hemodynamic effects of CO2 endoscopy during laparoscopy, the small bowel was insufflated to an intraluminal pressure of 15 mmHg during CO2 pneumoperitoneum. Nitrogen pneumoperitoneum was used to differentiate the effects from intraluminal and peritoneal CO2 insufflation.

RESULTS

The intraluminal pressures remained elevated and the bowel distended for the entire 3 h following bowel insufflation with air. Following intraluminal CO2 insufflation, both the intraluminal pressures and the bowel circumferences returned to preinsufflation values within 15 min. Intraluminal CO2 insufflation also led to systemic absorption of CO2 with significant metabolic and hemodynamic changes. These changes were effectively corrected by doubling minute ventilation.

CONCLUSIONS

Intraluminal CO2 was absorbed faster than intraluminal air. Although decreased bowel distention is certainly of practical value, endotracheal intubation needs to be done to effectively ventilate the absorbed CO2.

Impairment of cardiac performance by laparoscopy in patients receiving positive end-expiratory pressure

BACKGROUND

The cardiopulmonary effects of the combination of abdominal and thoracic pressures in humans have not been well delineated.

OBJECTIVE

To study the cardiopulmonary effects of 15 mm Hg of intra-abdominal pressure in the presence and absence of 10 cm H20 of positive end-expiratory pressure (PEEP).

DESIGN

Prospective.

SETTING

University hospital.

METHODS

Nine patients undergoing laparoscopic cholecystectomy had pulmonary compliance, cardiac output, exhaled carbon dioxide, and preload (left ventricular end-diastolic volume) determined at 4 points while undergoing ventilation with (1) no PEEP before pneumoperitoneum; (2) 10 cm H20 of PEEP and no pneumoperitoneum; (3) no PEEP and 15 mm Hg of pneumoperitoneum; and (4) 10 cm H20 of PEEP and 15 mm Hg of pneumoperitoneum. Preload and cardiac output were determined by means of transesophageal echocardiography. Pulmonary compliance and exhaled carbon dioxide were determined by an attachment to the end of the endotracheal tube.

MAIN OUTCOME MEASURES

Preload, cardiac output, exhaled carbon dioxide, and pulmonary compliance.

RESULTS

There was no significant change from baseline in preload, cardiac output, or pulmonary compliance when either PEEP or pneumoperitoneum was applied separately. However, there was a significant decrease in preload (P<.01), cardiac output (P = .01), and exhaled carbon dioxide (P =.04) when PEEP and pneumoperitoneum were applied together. Pulmonary compliance was not significantly affected at any of these points.

CONCLUSIONS

There was a significant reduction in preload and cardiac output when there was intra-abdominal pressure of 15 mm Hg in the presence of 10 cm H20 of PEEP. This combination of pressures may pose a contraindication to laparoscopic surgery.

Laparoscopic Roux-en-Y gastric bypass for morbid obesity

Surgery is currently the only effective treatment for morbid obesity. The two most commonly accepted operations are the Roux-en-Y gastric bypass and vertical banded gastroplasty. Although multiple authors have reported on a laparoscopic approach to gastric banding, the Roux-en-Y gastric bypass is a complex operation to be replicated using laparoscopic techniques. In this article, we describe our technique of the Roux-en-Y gastric bypass using a laparoscopic approach in four cases.

Cardiopulmonary responses to experimental venous carbon dioxide embolism

BACKGROUND

Although the low-flow CO2 insufflation rate used to initiate pneumoperitoneum may reduce the severity of potential venous embolism, its safety is not established.

METHODS

Anesthetized pigs were ventilated with room air at a fixed minute ventilation. After 1 h of baseline, they were intravenously infused with CO2 at the rate of 0.3, 0.75, or 1.2 ml/kg/min for 2 h (n = 5 for each group), followed by 1 h of recovery.

RESULTS

All animals experienced pulmonary hypertension, depressed stroke volume, hypoxemia, hypercarbia, and acidemia during intravenous CO2 infusion. They had systemic hypertension at the low rate of hypotension at the highest rate of infusion. End-tidal CO2 levels briefly decreased, then increased in all cases. In the highest rate group, three of the five animals (60%) died at 50, 65, and 100 min of infusion. These three animals had severe hypotension and hypoxemia, with visible coronary gas embolism. There was no patent foramen ovale at necropsy in any animals.

CONCLUSIONS

The low-flow insufflation rate exceeds the fatal rate of continuous intravenous CO2 infusion. End-tidal CO2 levels were increased in venous CO2 embolism, not decreased as seen in venous air embolism. Severe hypoxemia and hypotension are predictors of potentially fatal cases.

Oxidized type IV hypertriglyceridemic VLDL-remnants cause greater macrophage cholesteryl ester accumulation than oxidized LDL

We have previously shown that very low density lipoproteins (VLDL, Sf 60-400) from subjects with type IV hyperlipoproteinemia (HTG-VLDL) will induce appreciable cholesteryl ester accumulation in cultured macrophages (J774A.1). The present study examined whether copper-mediated oxidative modification of HTG-VLDL and their remnants would further enhance cholesteryl ester accumulation in J774A.1 cells. Incubation with oxidized VLDL-remnants caused the greatest increase in cellular cholesteryl ester concentrations (54-fold) relative to control cells (P = 0.001). HTG-VLDL and VLDL-remnants each induced similar increases in cholesteryl ester levels (32.3- and 35.8-fold, respectively; both P = 0.001), whereas incubation with oxidized HTG-VLDL brought about only a 20.6-fold increase in cholesteryl ester concentrations (P = 0.014). The increase in cellular cholesteryl ester concentrations induced by oxidized VLDL-remnants was significantly higher (P < or = 0.04) than that induced by all other lipoproteins tested including low density lipoprotein (LDL) and oxidized LDL which caused a 6.7- and a 35.1-fold increase (P < or = 0.0002 for both), respectively. Unlike HTG-VLDL and to a lesser extent VLDL-remnants, uptake of oxidized VLDL and oxidized VLDL-remnants did not require catalytically active, cell secreted lipoprotein lipase. Co-incubation with polyinosine, which blocks binding to the type I scavenger receptor, completely inhibited the cholesteryl ester accumulation induced by oxidized HTG-VLDL, oxidized VLDL-remnants and oxidized LDL (P < or = 0.02). We conclude that oxidation of VLDL-remnants significantly enhances macrophage cholesteryl ester accumulation compared to either HTG-VLDL, VLDL-remnants, or oxidized LDL. Uptake of oxidized VLDL and oxidized VLDL-remnants does not require catalytically active lipoprotein lipase, and involves a receptor that can be competed for by polyinosine.

Effects of adding C-19 versus C-21 progestin to conjugated estrogen in moderately hypercholesterolemic postmenopausal women

OBJECTIVE

Our purpose was to compare the effects on fasting plasma lipoprotein lipids of adding low dosage C-19 continuous progestin (dl-norgestrel) versus conventional low-dosage continuous C-21 progestin (medroxyprogesterone acetate) to cyclic conjugated estrogen therapy.

STUDY DESIGN

Nine hypercholesterolemic postmenopausal women with intact uteri were randomly assigned in a prospective, double-blind, two-period crossover study of conjugated estrogen plus either (1) dl-norgestrel (0.05 mg/day) or (2) medroxyprogesterone acetate (2.5 mg/day) for 1 year and after an appropriate washout period were switched to the alternative regimen for another year. Four subjects received conjugated estrogen only.

RESULTS

Compared with baselines, each of the C-19 and C-21 progestin regimens significantly increased plasma high-density lipoprotein cholesterol (15% vs 12%) and reduced the ratio of total cholesterol/high-density lipoprotein cholesterol (20% vs 15%, respectively), but only the former significantly reduced plasma triglycerides (24% vs 0.3%, p < 0.05).

CONCLUSIONS

Low dosages of either dl-norgestrel (C-19) or medroxyprogesterone acetate (C-21) when combined with conjugated estrogen significantly improve plasma lipoprotein lipids of postmenopausal women.

Uptake of type III hypertriglyceridemic VLDL by macrophages is enhanced by oxidation, especially after remnant formation

We previously showed that hypertriglyceridemic VLDL (HTG-VLDL, Sf 60 to 400) from subjects with type III (E2/E2) hyperlipoproteinemia do not induce appreciable cholesteryl ester (CE) accumulation in cultured macrophages (J774A.1). In the present study, we examined whether oxidation of type III HTG-VLDL would enhance their uptake by J774A.1 cells. Type III HTG-VLDL were oxidized as measured by both conjugated-diene formation and increased electrophoretic mobility on agarose gels. Both LDL and type III HTG-VLDL undergo oxidation, albeit under different kinetic parameters. From the conjugated-diene curve, type III HTG-VLDL, compared with LDL, were found to have a 6-fold longer lag time, to take 6-fold longer to reach maximal diene production, and to produce a 2-fold greater amount of dienes but at half the rate (all P < .005). Incubation of macrophages with either native type III HTG-VLDL or LDL (50 micrograms lipoprotein cholesterol/mL media for 16 hours) caused small increases (4-fold and 2.7-fold, respectively) in cellular CE levels relative to control cells (both P = .0001). After 24 hours of CuSO4 exposure, we found that oxidized type III HTG-VLDL and LDL caused a 9.4-fold and 10.5-fold increase, respectively, in cellular CE levels (P = .0001). We next examined whether extending the exposure period for type III HTG-VLDL to CuSO4 beyond 24 hours would further enhance its ability to induce macrophage CE accumulation. After 48 hours of CuSO4 exposure, type III HTG-VLDL and LDL caused 21.3-fold and 11.6-fold increases, respectively, in cellular CE levels (P = .0001). The cellular CE loading achieved with 48 hour-oxidized type III HTG-VLDL was significantly higher than either 24 hour-oxidized type III HTG-VLDL (2.3-fold, P = .003) or 48 hour-oxidized LDL (1.8-fold, P = .012). There was no significant difference between the CE loading achieved by incubation of cells with either 24 hour-oxidized type III HTG-VLDL, 24 hour-oxidized LDL, or 48 hour-oxidized LDL (P > or = .518). In this study, we also examined whether partial lipolysis (19% to 50% triglyceride hydrolysis) of type III HTG-VLDL to produce remnants would increase the susceptibility of the lipoprotein to oxidative modification and subsequent cellular CE loading. Forty-eight hour-oxidized type III VLDL-remnants stimulated CE accumulation 30.4-fold over baseline (P = .0001). In contrast, nonoxidized type III VLDL-remnants caused the same very low level of CE loading as did native type III HTG-VLDL (P = .680). The increase in cellular CE levels achieved with 48 hour-oxidized type III VLDL-remnants was significantly higher than that achieved with 48 hour-oxidized type III HTG-VLDL (P = .047). In conclusion, we have shown that oxidized type III HTG-VLDL will induce macrophage CE accumulation well above levels achieved with oxidized LDL. In addition, we also showed that by forming a VLDL-remnant before oxidative modification, we can further enhance macrophage CE accumulation. These results provide a potential mechanism for the atherogenicity of type III HTG-VLDL and their remnants.

Uptake of hypertriglyceridemic very low density lipoproteins and their remnants by HepG2 cells: the role of lipoprotein lipase, hepatic triglyceride lipase, and cell surface proteoglycans

Hypertriglyceridemic very low density lipoproteins (HTG-VLDL, S(f) 60-400) are not taken up by HepG2 cells. However, addition of bovine milk lipoprotein lipase (LPL) at physiological concentrations markedly stimulates uptake. In the present study, we determined whether: a) LPL catalytic activity is required for uptake, b) LPL functions as a ligand, and c) cell surface hepatic triglyceride lipase (HL) and/or proteoglycans are involved. Incubation of HepG2 cells with HTG-VLDL plus LPL (8 ng/ml) increased cellular cholesteryl ester (CE) 3.5-fold and triglyceride (TG) 6-fold. Heat-inactivation of LPL abolished the effect. Addition of tetrahydrolipstatin (THL, an LPL active-site inhibitor) to HTG-VLDL + LPL, inhibited the cellular increase in both CE and TG by greater than 90%. Co-incubation of HTG-VLDL + LPL with heparin, heparinase, or heparitinase, blocked CE accumulation by 70%, 48%, and 95%, respectively, but had no effect on the increase in cellular TG. Pre-treatment of cells with 1 mM 4-methylumbelliferyl-beta-D-xyloside, (beta-xyloside) to reduce cell surface proteoglycans inhibited the increase in CE induced by HTG-VLDL + LPL by 78%. HTG-VLDL remnants, prepared in vitro and isolated free of LPL activity, stimulated HepG2 cell CE 2.8-fold in the absence of added LPL, a process inhibited with THL by 66%. Addition of LPL (8 ng/ml) to remnants did not further enhance CE accumulation. HepG2 cell HL activity, released by heparin, was inhibited 95% by THL. The amount of HL activity and immunoreactive mass, released by heparin, was reduced 50-60% in beta-xyloside-treated cells. These results indicate that physiological concentrations of LPL promote HepG2 cell uptake of HTG-VLDL primarily due to remnant formation and that LPL does not play a major role as a ligand. HL activity and cell surface proteoglycans significantly enhance the subsequent uptake of VLDL remnants.

Cardiopulmonary responses to intravenous infusion of soluble and relatively insoluble gases

BACKGROUND

Carbon dioxide is the current gas of choice for pneumoperitoneum, but hemodynamic and acid-base effects secondary to its systemic absorption have been reported. Various studies have suggested inert gases as alternatives.

METHODS

We studied the cardiopulmonary responses to intravenous infusion of carbon dioxide, nitrous oxide, argon, helium, and nitrogen in anesthetized swine. The gas was infused into the femoral vein at a rate of 0.1 ml . kg-1 . min-1 for 30 min. The changes in end-tidal CO2, mean arterial pressure, hemodynamics, and arterial blood gases were compared to baseline values.

RESULTS

No animals died during infusion of the soluble gases (CO2 and N2O). Three of the five pigs infused with nitrogen died suddenly at 20 and 30 min of infusion. The animals in the insoluble gas groups (Ar, He, N2) experienced clinical pulmonary gas embolism and severe acidemia, hypercapnea and tachycardia.

CONCLUSIONS

Venous gas embolism is poorly tolerated when the gas is relatively insoluble. Insoluble gases should not be used for pneumoperitoneum when there is any risk of venous gas embolism.

Clinical practice guidelines in nutrition support: can they be based on randomized clinical trials?

As rationing of health care services becomes an increasing reality, the pressure to justify interventions such as nutrition support will intensify. The establishment of clinical practice guidelines is one means of providing practitioners with such justification, but clinical practice guidelines for nutrition support cannot be based primarily on prospective randomized trials. This situation arises as the result of limitations specific to nutrition support whereby the most malnourished patients-those who appear most likely to show a benefit from the treatment-cannot be randomized to a no feeding group and are therefore excluded from participation in the study. As the result of this limitation, marginal candidates for nutrition support have been included in some trials, potentially masking the benefits of this treatment. An additional problem limiting present interpretation of published reports of randomized trials in nutrition support is the fact that ongoing research continues to yield improvements in the clinical practice of nutrition support. Thus the nutrition support group in such trials may not have received this treatment according to current practice. The A.S.P.E.N. Guidelines, based on both randomized prospective trials and other types of evidence, represent an important contribution to the practice of nutrition support. Testing of the performance of these and other guidelines in clinical practice and further outcomes research will be important steps toward revision and improvement of nutrition support, but may be difficult to achieve in the near future.

The impact of laparoscopic cholecystectomy on the treatment of symptomatic cholelithiasis

BACKGROUND

There has been a debate about the cost-effectiveness of laparoscopic cholecystectomy (LC), as well as a concern regarding its possible overutilization and changes in the indication for surgery.

METHODS

A retrospective analysis of all cholecystectomies performed at UCDMC from 1988 to 1994 was done. The annual rate of cholecystectomy increased by 50% in 1990 when LC was introduced but has since stabilized at a rate 11% higher than the rate before LC. The disease status and severity did not change.

RESULTS

The incidence of nonelective surgery remained stable at 31.2% to 37.5%. Elective cholecystectomy had lower mortality (0.16% vs 1.8%, P = 0. 029), morbidity (2.6% vs 11.2%, P = 0.0001), and conversion rate (2. 6% vs 16%, P = 0.0001) and a shorter length of stay (2.1 days vs 5.4 days), compared with nonelective procedure.

CONCLUSIONS

The indication for surgery in cholelithiasis has not changed since the introduction of LC. In patients with symptomatic gallstones, early elective surgery is recommended and may be more cost-effective.

Treatment of familial hypercholesterolemia in children and adolescents: effect of lovastatin. Canadian Lovastatin in Children Study Group

OBJECTIVE

Familial hypercholesterolemia (FH), an inherited autosomal dominant disorder of lipoprotein metabolism, is associated with premature atherosclerosis. The recommended pediatric therapy consists of dietary intervention and, when necessary, treatment with bile acid-binding resins. However, compliance has been poor in many children. Therefore, our objectives were to determine the efficacy, safety, and tolerance of the short-term use of lovastatin, a 3-hydroxy 3-methylglutaryl coenzyme A reductase inhibitor, in the control of severe FH in a male pediatric population and to evaluate the dose-response relationship.

METHODS

Sixty-nine male patients with FH 12.9 +/- 2.4 years of age (mean +/- SD) participated in this multicenter, randomized, double-blind trial. After a 4-week placebo period, the patients were allocated to four treatment groups (lovastatin 10, 20, 30, 40 mg/d) for 8 weeks. Plasma lipid and apolipoprotein (Apo) concentrations were measured every 2 weeks. Clinical and laboratory evidence of adverse events was monitored periodically throughout the study.

RESULTS

All lovastatin doses reduced total cholesterol (-17% to -29%), low density lipoprotein cholesterol (-21% to -36%), and ApoB (-19% to -28%) concentrations. A dose-response relationship was seen, and between-group comparisons showed that results were significantly improved up to a dose of 30 mg/d. We observed a 7% increase in high-density lipoprotein cholesterol and a 4% increase in ApoA1 concentrations. The medication was well tolerated by all patients. No serious clinical adverse experience was reported. Lovastatin increased aspartate aminotransferase concentrations, but there was no evidence of a dose-response relationship, and no value exceeded two times the upper limit of normal. No significant change in alanine aminotransferase was observed. Three patients had marked (more than three times the upper limit of normal) asymptomatic elevations in their creatine kinase values, which returned spontaneously to normal, and no action was required regarding the drug.

Lipids and stroke: a paradox resolved

BACKGROUND

Although dyslipidemia is a well established risk factor for coronary artery disease, its relationship to ischemic cerebrovascular disease has remained unclear, perhaps because of the heterogeneous nature of strokes.

METHODS

In a case-control study, we measured the serum concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, serum triglycerides, and lipoprotein(a) levels and determined the apolipoprotein E phenotype and serum ferritin level in 90 consecutive systematically investigated patients with stroke or transient ischemic attack of atherothrombotic origin. Ninety age-, sex-, and community-matched subjects served as controls.

RESULTS

Plasma total cholesterol (5.99 vs 5.45 mmol/L [232 vs 211 mg/dL], P=.003), low-density lipoprotein cholesterol (3.96 vs 3.45 mmol/L [153 vs 133 mg/dL], P=.004), and serum triglyceride (2.09 vs 1.82 mmol/L [8] vs 70 mg/dL], P=.03) levels were significantly higher among the patients with atherothrombotic strokes and transient ischemic attacks than among the control subjects. The inverse was true for high-density lipoprotein cholesterol (1.07 vs 1.18 mmol/L [41 vs 46 mg/dL], P=.02) levels. No significant differences were found in lipoprotein(a) levels or in the distribution of apolipoprotein E phenotypes or allele frequency. Serum ferritin levels did not differ significantly between patients and control subjects.

CONCLUSIONS

Elevated low-density lipoprotein cholesterol and triglyceride levels are significant independent risk factors in patients with proven atherothrombotic cerebrovascular disease manifesting as stroke or transient ischemic attack. The level of stored serum iron, as reflected by serum ferritin levels, does not correlate with the presence of atherothrombotic cerebrovascular or coronary disease.

Is outpatient laparoscopic cholecystectomy wise?

The authors report a prospective analysis of their experience with 506 consecutive laparoscopic cholecystectomies to examine the appropriateness of outpatient or same-day laparoscopic cholecystectomy. Thirty-eight patients experienced at least one postoperative complication. The complication was clinically evident or suspected in only 4 of these 38 patients within 8 h following surgery. Thirty-nine percent and 76% of complications were clinically detected at 24 and 48 h, respectively. Nausea and vomiting occurred among 32% of all patients on the day of operation and extended into the 1st postoperative day in 10%. Compared to predicted values, forced vital capacity was 61 +/- 5% 1 h postoperatively in 32 patients studied. At 6 and 24 h postoperatively, forced vital capacity was 63 +/- 7% and 66% respectively. Postoperative analgesic medication requirement was determined in 220 patients who were provided with a patient-controlled intravenous morphine analgesia machine with no basal rate. Consumption of morphine was highly variable but substantial on the day of operation: 17 +/- 16 mg. Most complications of laparoscopic cholecystectomy, including life-threatening complications, are not apparent by 8 h postoperatively and may not be apparent at 24 h. The potential for delay in the diagnosis and treatment of complications, variable but substantial analgesic requirements, impaired postoperative ventilation, and postoperative gastrointestinal dysfunction argue for the need to use great caution in selecting patients for outpatient laparoscopic cholecystectomy. Criteria are proposed to identify patients who are safest for outpatient laparoscopic cholecystectomy.