A Single-Center Experience with Simultaneous IVC Filter Placement during Gastric Bypass

Introduction

In recent years, increasing numbers of patients are choosing the option of gastric bypass for weight reduction. In 2004, 121,055 bariatric procedures were performed, a nine-fold increase compared to 1998, when 13,386 bariatric procedures were done.¹ This increase in bariatric procedures corresponds to an increase of national inpatient hospital costs by more than eight times, excluding physician costs, from $147 million in 1998 to $1.26 billion in 2004.² With the number of bariatric procedures expected to rise in the ensuing years, addressing the specific issues of the bariatric patient will become increasingly important.^3–6

Morbid obesity is defined as a body mass index (BMI) > 40 kg/m² or 100 lbs. over ideal body weight and is a major national health concern.⁷ A recent national consensus concluded that the number of obese individuals in the United States has increased from 12% in 1990 to almost 20% in 1998.^8,9 A separate NIH consensus panel concluded that surgery is a viable option in patients with either a BMI > 40 kg/m² or for patients with a BMI > 35 kg/m² and significant medical comorbidities, or who have failed a major nutritional weight-loss program.^8,9

Initial reports on surgical weight-loss procedures concluded that morbidly obese patients with concomitant sleep apnea syndrome or pulmonary hypertension have a higher incidence of perioperative pulmonary embolism (PE).¹⁰ These observations were never formally evaluated in prospective, randomized trials nor were they addressed in ongoing investigations of bariatric surgical weight loss procedures. The relatively high PE rate in our own initial experience with surgical weight-loss procedures prompted us to review our data for these patients.

PE is a known, but preventable, cause of perioperative death that may occur at any time intraoperatively to several weeks postoperatively. However, to date, there has been no formal consensus or recommendation for the prevention of PE in this young, high-risk group of patients, despite the growing popularity of these operations. Currently accepted practices for the prevention of PE include perioperative subcutaneous heparin injections and sequential compression devices (SCD). Inferior vena cava (IVC) filter placement has been advocated in patients with a history of deep venous thrombosis (DVT), PE, or pulmonary hypertension. A recent series by Keeling et al, where prophylactic IVC filters were placed in 14 patients with a history of venous stasis and hypercoagulability, in addition to DVT and PE, showed that this procedure could be done safely, with no thromboembolic events. Although prophylactic IVC filter placement may be beneficial, the logistics are both numerous and challenging.

The open gastric bypass has been the gold standard weight-loss procedure for the past four decades.^12–15 Laparoscopic gastric bypass has recently been introduced as an alternative procedure for weight loss.¹⁶ Both procedures are feasible and safe, and have successfully reversed the adverse sequelae of morbid obesity. Data on the long-term sequella of permanent and retrievable filter placement specifically in this patient population are evolving.

Whether retrievable filters will be superior to permanent ones remains to be elucidated, but clearly, using a device that has proven complications only during the high-risk perioperative period, would seem superior. All of the current retrievable filters are considered “optional” because they can either be retrieved or left in as permanent filters. In the United States, there are currently three FDA-approved retrievable filters: (1) Optease (Cordis Endovascular, Warren, New Jersey) (2) Bard Recovery Filter (C.R. Bard, Inc., Tempe, Arizona), and (3) Günther Tulip (Cook, Inc., Bloomington, Indiana).

Prior indications for IVC filter placement by Sugerman et al included the history of DVT, PE, pulmonary hypertension (defined as mean pulmonary artery pressure > 40 mmHg), and venous stasis (presence of stasis dermatitis). At our institution, we place IVC filters in patients undergoing open and laparoscopic gastric bypass surgery if they have a history of one of the following: venous stasis, DVT, PE, pulmonary hypertension, hypercoagulability, or a BMI > 55 kg/m². Surgeon preference guides determine which device is placed.

The Montefiore Technique for Prophylactic IVC Filter Placement in Gastric Bypass

All patients having IVC filters placed at the time of open Roux-en-Y gastric bypass surgery were placed ona Skytron Heavy Duty 6500 fluoroscopic table, which was reversed and filters were placed prior to the bypass procedure. A cephalad extension is added to the “head” (“original foot”) of the table to permit imaging of the patient’s abdomen. Imaging is performed using a portable OEC 9800 digital fluoroscope. A transfemoral percutaneous puncture is made with an 18G needle, and a Magic Torque (Boston Scientific, Watertown, Massachusetts) wire was fluoroscopically guided into the IVC. The needle is then exchanged for a 6 Fr, 7 Fr, or 12 Fr sheath supplied by the Trapease (Cordis Endovascular), Simon-Nitinol (Nitinol Medical Technologies, Boston, Massachusetts), Greenfield (Boston Scientific) or Bard Recovery IVC filter systems, respectively. Vena cavography is performed to measure IVC diameter, confirm patency, and identify the confluence of the iliac veins. Selective left and right renal venography is then performed using a Cobra 1 (C1) catheter (Cook). A Trapease, Simon-Nitinol, Greenfield, or Bard Recovery filter is then deployed into the infrarenal IVC under fluoroscopic control. Completion venography post-IVC filter deployment confirmed filter position as well as patency of the IVC and renal veins.

IVC Filter in Open Gastric Bypass

Pulmonary embolism is one of the most devastating complications, with an incidence of 2–4% in morbidly obese patients undergoing open gastric bypass.¹¹ Despite the use of subcutaneous heparin injections, SCDs, and prior indications for IVC filter placement by Sugerman et al,¹⁰ a significant number of PE and death from PE were observed in our practice, until we began placing IVC filters in patients undergoing OGB with a BMI > 55 kg/m². Our retrospective review compared OGB patients receiving IVC filters for prior indications by Sugerman et al¹⁰ (Group I) to all patients receiving IVC filters for a BMI > 55 kg/m² prophylactically (Group II). The pulmonary embolism rate was dramatically reduced in the patients with a high body mass index, again those with a BMI > 55 kg/m². The perioperative pulmonary embolism rate in patients undergoing Roux-en-Y gastric bypass surgery was reduced from 13% (4 of 31; 95% CI 4–30%) to 0% (0 of 33; 95% CI 0–11%) when a BMI > 55 kg/m² was used as an indication for IVC filter placement.

In order to confirm our observations, another group of patients with a BMI > 55 kg/m² undergoing open gastric bypass were randomized, therefore demonstrating the benefit of IVC filter placement in preventing PE and death from PE, even with the use of subcutaneous heparin injections and SCDs.17 GROUP IIIA patients (n = 17, average BMI 63 kg/m² ± 5 kg/m²) underwent IVC filter placement with OGB and GROUP IIIB patients (n = 18, average BMI 63 kg/m² ± 5 kg/m²) underwent OGB, only without IVC filter placement. The 17 patients with a BMI > 55 kg/m2 (GROUP IIIA) who underwent OGB and IVC filter placement had no perioperative pulmonary emboli. This was in striking contrast to the 18 patients with a BMI > 55 kg/m² (GROUP IIIB) undergoing OGB, only without IVC filter placement who had a 28% perioperative PE rate and 11% PE mortality rate (P < 0.05). All patients and group characteristics were similar and outlined. Even from this small randomization study, the evidence is overwhelming and clearly demonstrates the benefit of placing IVC filters in patients with a high BMI undergoing OGB.

This benefit was not as profound when the entire cohort of morbidly obese patients was analyzed. In fact, the overall morbidity and mortality of all morbidly obese patients undergoing OGB surgery was minimally reduced. There is no doubt, however, that a subgroup of morbidly obese patients with high BMIs, i.e., those with a BMI greater than 55 kg/m², improve their morbidity and mortality remarkably when an IVC filter is placed.

Despite the benefits, the logistics of IVC filter placement in this group of patients are both numerous and challenging. First, the patient’s obesity prevents their positioning on standard angiographic tables. Standard tables in interventional radiology or cardiac catheterization suites holdpatients up to 350–400 lbs, whereas the 6,500 Heavy- Duty Skytron operating room table holds patients up to 800 lbs. In addition, the percutaneous femoral puncture is cumbersome, due to the massive abdominal pannus. We circumvented this problem by using a tincture of benzoin and silk tape to retract the abdominal pannus for improved access to the groin.

Another possible access site for IVC filter placement is the internal jugular vein, which can be localized using ultrasonography. This approach was not used in these patients because the majority of these patients had previous Swan-Ganz catheter and/or central venous pressure lines placed. Due to the patient’s body habitus, the fluoroscopic images obtained are not as clear as those performed in relatively thin patients, but the images provide adequate visualization of the IVC, iliac, and renal veins for filter placement. By performing simultaneous IVC filter placement and open gastric bypass, one eliminates the need for an additional admission or day of hospitalization.

IVC Filter Placement in Laparoscopic Gastric Bypass

Similar observations have not been made in those patients undergoing laparoscopic gastric bypass. It has been postulated that increasing intra-abdominal pressure not only reduces venous return by inferior vena cava compression, but also incites a physiologic and inflammatory milieu that might initially result in a hypercoagulable state.¹⁸

In our unpublished data from August 2001 to August 2003, a retrospective analysis was performed on 213 patients (Average BMI 51 kg/m2 ± 6 kg/m²) undergoing laparoscopic gastric bypass. IVC filters were placed for a history of DVT, PE, or pulmonary hypertension. In this 24-month period, 109 of the 213 patients had a BMI > 55 kg/m². None of these patients required an IVC filter prior to surgery. These patients were compared to our previously reported group of 193 patients (average BMI 51 kg/m2 ± 7 kg/m²) undergoing the open Roux-en- Y gastric bypass procedure from July 1999 through April 2001. Eight of these patients had a preoperativeIVC filter placed for a history of DVT (3 patients), PE (2 patients), or documented pulmonary hypertension (3 patients). None of these 8 patients receiving IVC filters had a perioperative PE, and all had a BMI > 55 kg/m². Four patients did not meet criteria for IVC filter placement and developed a fatal (3) or non-fatal (1) PE. All 4 patients had a BMI > 55 kg/m² and had similar risk factors, hypercoagulable profiles, and other comorbidities, as others in the group. There were no patients with a BMI > 55 kg/m² undergoing laparoscopic gastric bypass that had a symptomatic deep venous thrombosis or pulmonary embolism and only one of the 213 patients undergoing laparoscopic gastric bypass developed a deep venous thrombosis resulting in a pulmonary embolism.

Perhaps the release of tissue factor during open surgery (open gastric bypass) may outweigh the hyperocoagulable effects of vena caval compression (laparoscopic gastric bypass).¹⁹

Retrievable IVC Filters

There are many well-documented long-term complications of permanent inferior vena cava (IVC) filters. These include IVC thrombosis, increased rate of deep vein thrombosis (DVT), peripheral thrombosis, migration, tilt, filter infection, and erosion through the IVC,^20,21 with DVT and IVC thrombosis being the most common long-term complication after IVC filter insertion, reported at a rate of 23–36% and a 4–11%, respectively.²² In an effort to reduce the number of these complications in patients that had a transient need for filter protection, retrievable and optional filters were created and implemented. However, there are also caveats related to these newer devices. First, many of the implanted removable devices will never be removed, some reports have stated as many as 65% of optional filters are transitioned to permanent filters.²³ This subset of filters puts the patient at the same risk as those of permanent filters. Although they do not put the patient at the same risk for long-term complications, of the filters retrieved, there are complications associated with their removal. Such complications include failure to retrieve the filter, IVC perforation, PE from retained clot, and filter embolization.²⁵ Further studies are needed to yield data on the long-term outcome of retrievable filters placed in gastric bypass patients.

Post-operative Anticoagulation

Post-operative anticoagulation after IVC filter placement in morbidly obese patients has not been studied. Presumably, anticoagulation would reduce filter thrombosis. Options for anticoagulation in the post-operative patient include coumadin or subcutaneous-fractionated heparin. Risks for both are well described and include bleeding, warfarin-induced skin necrosis, heparin-induced thrombocytopenia (HIT), osteoporosis and other endocrine-associated abnormalities. Dosing of coumadin in these patients with small gastric pouches and reduced gastrointestinal absorptive area likewise can be challenging, and most patients are reluctant to undergo long-term subcutaneous fractionated heparin injections. We recommend postoperative anticoagulation after IVC filter placement in these patients only if they have a history of hypercoagulability.

Long-Term Follow Up

In our own experience, a series of 41 patients undergoing IVC filter placement at the time of open gastric bypass, there have been two patients with post-operative DVT on the side of venous puncture for IVC filter insertion and one IVC thrombosis 4 months postoperatively. Both patients with post-operative DVT presented 3 months after IVC filter placement, with lower extremity pain and edema, and were diagnosed with duplex sonography. These patients were both treated with intravenous heparin and subsequent warfarin therapy. Neither patient developed a PE. The patient with IVC thrombosis presented 1 week after the onset of symptoms and was found to have a compartment syndrome in both lower extremities requiring bilateral fasciotomies. This patient subsequently died after 2 months of hospitalization from septic complications related to the gastric bypass procedure. To date, the other 38 patients have been followed without any documented complications related to IVC filter placement.

As stated earlier, our initial experience with simultaneous IVC filter placement and open gastric bypass was quite revealing. The perioperative PE rate in patients undergoing open gastric bypass surgery was reduced from 17% (4 of 23) to 0% (0 of 33) when a body mass index > 55 kg/m² was used as an indication for IVC filter placement. This constitutes a 72% reduction in the risk of PE (RR, 0.28; 95% CI, 0.05–0.98; P < .05). In addition, the 30-day mortality from PE was reduced from 13% to 0% (P = .1). Clearly, IVC filter placement at the time of open gastric bypass is invaluable. In our series of 213 patients undergoing laparoscopic gastric bypass, there was only one patient thathad a PE. This patient also had a history of previous DVT. Despite the theoretical hindrance of venous return and vena caval compression seen with pneumoperitoneum, fewer pulmonary emboli have been observed in the laparoscopic group. The 14% late complication rate (one IVC thrombosis, two insertion-site DVTs) that we observed may be reversed with the use of a retrievable IVC filter. This prompted us to initialize a prospective, randomized study comparing early and late sequelae of IVC filter placement (permanent vs. retrievable) in those patients undergoing open gastric bypass. This study will help elucidate the role of retrievable IVC filters in the morbid obese patient undergoing open gastric bypass surgery. Presently, the body of literature published on the use of retrievable filters in bariatric patients is limited to case reports.²⁵

Limitations

While it is evident that our observations support the placement of IVC filter during open gastric bypass, these findings were made early in our experience. Initial strategies for the prevention of DVT included the use of unfractionated heparin at standard dosing. Perhaps the use of weight-adjusted fractionated heparin may reduce the rate of DVT and PE in this high-risk patient population. We placed both permanent and retrievable filters. To clearly analyze the benefits of retrievable versus permanent IVC filters, these patients would need to be investigated separately. Complications occurring at removal of retrievable filters and long-term complications of permanent filters may limit their use in this patient population and remain to be elucidated.