Long-Term Outcomes and Weight Loss After Bariatric Embolization of the Left Gastric Artery

Abstract: Objectives. Bariatric embolization of the left gastric artery is a promising technique to induce weight loss in obese patients. We aimed to assess long-term effects. Methods. Patients with severe obesity were recruited to undergo left gastric artery embolization via transradial access. We report clinical outcomes and weight loss up to 2 years. Results. We completed 7 procedures successfully in 7 men with severe obesity after diagnostic coronary angiography. Median weight was 160 kg (interquartile range, 140.0-180.0 kg) and body mass index was 49.4 kg/m² (interquartile range, 43.2-61.7 kg/m²). Acutely, no adverse events were reported other than mild epigastric pain, which subsided within 24 hours with proton pump inhibitors. No delayed gastrointestinal complications were reported up to 2 years after index procedure. One patient died of pulmonary embolism 18 months after the procedure. One patient underwent a second embolization procedure after it was shown that the left gastric artery was patent 18 months after the initial procedure. Compared with baseline in the 6 surviving patients, overall weight loss was 7.7% (range, 3.2%-14.1%). Conclusions. Bariatric embolization of the left gastric artery may induce weight loss, which appears sustained up to 2 years. Spontaneous recanalization of the left gastric artery may pave the way for repeat procedures and other interventions. Further research is necessary to define the benefits, safety, and indications for this technique.

J INVASIVE CARDIOL 2020;32(8):310-314. 

Key words: bariatric embolization, cardiovascular prevention, obesity

Obesity affects 13% of adults according to the World Health Organization (2016 data).¹ From 1975 to 2014, the global age-standardized prevalence of obesity has more than doubled.² This obesity pandemic reaches alarming proportions in higher income countries such as the United States, where up to 39.8% of the population is obese³ and severe obesity (body mass index [BMI] ≥40 kg/m²) is progressing even more rapidly.^4,5 Obesity is correlated with mortality, morbidity, and reductions in quality of life, with cardiovascular disease responsible for the majority of deaths related to a high BMI.⁶ 

It is increasingly recognized that there is a strong genetic susceptibility that modulates food intake as well as energy expenditure and storage to determine the obese phenotype.^7,8 Moreover, we are now beginning to understand why derangements in the hormonal regulation of energy homeostasis contribute to the resistance of the body to weight loss.^9,10 In patients with severe obesity, bariatric surgery remains the gold standard when diet and lifestyle modifications have failed. The efficacy of bariatric surgery to control type 2 diabetes has been demonstrated in randomized trials.^11-13 The largest of these, the STAMPEDE trial, showed that a larger proportion of patients had a glycated hemoglobin level of 6% or less with bariatric surgery as opposed to medical therapy, up to 5 years after the procedure.¹³ Recent data also highlighted the efficacy of bariatric surgery to control arterial hypertension.¹⁴ Moreover, prospective non-randomized data suggest a significant impact of bariatric surgery on cardiovascular outcome in primary prevention.^15-17 However, bariatric surgery in patients with established atherosclerotic disease has been associated with a higher risk of periprocedural complications and of major adverse cardiac and cerebrovascular outcomes during long-term follow-up compared to patients with no atherosclerotic disease.^18,19 

Although several weight-loss drugs are now available for obese patients with established atherosclerotic disease, their long-term efficacy and safety remain controversial. Furthermore, despite the Food and Drug Administration (FDA) recommendation of inducing ≥5% weight loss as cut-off value, this effect might rapidly recede upon weight-loss drug interruption and the number of side effects may limit long-term patient compliance.^18-21 

Bariatric embolization of the left gastric artery is a relatively novel percutaneous technique that aims to induce weight loss. Purported mechanisms of actions have not yet been well characterized, but might involve reductions in the levels of ghrelin (an orexigenic hormone synthesized in the gastric fundus), changes in gastric acid production, mobility, and possibly gastrointestinal absorption.²² On the other hand, potential serious complications, such as gastric perforation, bowel obstruction, mucosal tears, or gastrointestinal bleeding, have been reported.²² We and others have previously reported the safety and early weight loss after the index procedure.²³ Herein, we report the 2-year clinical results and weight loss in this pilot study.

Methods

Methods for this pilot study have been described previously.²³ Briefly, severely obese patients (>18 years of age) presenting for coronary angiography were recruited to participate. Desire to proceed to bariatric surgery, history of gastric surgery, or any condition associated with unintentional weight loss were considered to be exclusion criteria. The celiac artery was selectively cannulated via a right radial approach with a 5 Fr, JR 4, 125 cm catheter (Cordis). The left gastric artery was then selectively catheterized with a Renegade 18 microcatheter (Boston Scientific). After angiographic confirmation of positioning, 300-500 μm polyvinyl alcohol particles (Cook Medical) were injected until stasis was obtained. The procedures were performed from February 2016 to December 2017 at the Bács-Kiskun County Hospital, Hungary, by an interventional cardiologist (ZR) directly following diagnostic coronary angiography. All procedures were performed in accordance with local hospital regulations. Patients provided informed consent. 

Continuous data are presented as mean ± standard deviation or median (interquartile range [IQR]) according to data distribution, whereas categorical data are described as frequency (percentage). 

Results

Seven patients were recruited and underwent successful bariatric embolization of the left gastric artery (Table 1). These patients were all male and presented with severe obesity with initial weight of 160.0 kg (IQR, 140.0-180.0 kg) and BMI of 49.4 kg/m² (IQR, 43.2-61.7 kg/m²). Six of the 7 patients reported mild epigastric discomfort, which was treated with proton pump inhibitors and resolved within 24 hours. After hospital discharge, no further gastrointestinal events occurred. One patient died of pulmonary embolism 18 months after the index procedure.

Weight loss was 6.7% (IQR, 3.4%-10.0%) after 2 months, 10.1% (IQR, 5.4%-14.3%) after 6 months, 7.4% (IQR, -7.1%-21.3%) after 12 months and, in the 6 surviving patients, 7.7% after 2 years (IQR, 3.2%-14.1%), although some patients presented weight gain during the second year (Table 2 and Figure 1). Absolute weight loss after 2 years was 11.0 kg (IQR, 4.25-21.5). Of note, 1 patient had presented a paradoxical reaction with immediate weight gain after left gastric artery embolization. However, 3 patients maintained weight loss of over 10 kg through to 24 months.

After 18 months, 1 patient asked to undergo a repeat procedure. This patient had initially lost 10 kg, but regained all lost weight within the first year. Left gastric angiography revealed recanalization of the distal vasculature of the left gastric artery and embolization was subsequently performed a second time (Figure 3). This patient went on to lose another 11 kg in the 6 months following the second procedure. However, he once again regained all lost weight a second time. Repeat angiography is planned. 

Discussion

Seven small series of left gastric artery bariatric embolization have been reported so far (Figure 2).^23-29 In the largest series to date, with 20 patients, average weight loss was at 5.5% (7.6 kg) after 12 months. Other pilot studies have published a similar range of weight loss that meets the threshold of 5% set by the FDA to market weight loss pharmacotherapy. This threshold is based on the assumption that a 5% weight loss will lead to reductions in cardiovascular risk factors that may in turn lead to a decrease in cardiovascular events.^20,30,31 Yet, side effects and poor long-term compliance with weight-loss drugs remain an issue. Furthermore, it has been demonstrated that initial weight loss might regress within 6 months of interruption of drug treatment.²¹ 

Our series is the second to report weight loss up to 2 years. As in the series by Kipshidze et al,²⁹ some of our patients experienced weight gain in the second year, as is often described in many weight loss interventions such as low-calorie diets, weight-loss pharmacotherapy, and in less invasive bariatric surgical procedures. This signal may point to a waning of the effect of the initial procedure within the first year in some patients. Notwithstanding, 3 of our patients did maintain impressive absolute weight losses. Because our patients presented with severe obesity, it is unclear whether our findings are applicable to lesser degrees of obesity. 

Interestingly, 1 patient underwent a second procedure after 18 months. Repeat angiography revealed that the left gastric artery vascularization had resumed despite initial distal flow interruption. Recanalization of arteries following embolization has previously been described histologically in sheep uterine arteries.³² This is important, as it may partly explain the waning effect within the first year. Secondly, the fact that the procedure does not imply irreversible occlusion may allow secondary surgical procedures, including bariatric surgery. Thirdly, this observation paves the way for repeat procedures with the goal of perpetuating or increasing weight loss.

All our procedures were successfully performed via radial access, which we believe should be used systematically in patients with obesity essentially because of the reduction in bleeding associated with radial access in obese patients.^33,34 

The modest reported weight loss suggests that bariatric embolization cannot be compared with bariatric surgery. However, niche indications could be considered such as weight loss prior to major surgery such as cardiac surgery/transplantation. The procedure could also be performed in high-risk patients, including older patients with cardiovascular disease who are developing insulin resistance or who wish to avoid putting on weight when they stop smoking. Furthermore, bariatric surgery is not without risks and patients who are deemed to be too high risk for bariatric surgery may benefit from this procedure.^18,19

With regard to safety, most series have reported minor gastric ulcerations. It is now routine to administer proton pump inhibitors prior to any potential left gastric artery embolization. However, in one retrospective series, a more severe complication of gastric perforation was reported.²⁵ Thus, more data in the setting of a randomized trial are needed to establish both the efficacy and the risks of this technique.

Conclusion

Transradial left gastric artery embolization is a promising percutaneous technique to potentially induce significant weight loss in obese patients who are not good candidates for standard bariatric surgery. Yet, randomized controlled studies with larger patient populations are eagerly awaited to further delineate short- and long-term efficacy and safety.

From the ¹Quebec Heart and Lung Institute, Quebec, Canada; ²Semmelweis University of Budapest, Cardiac and Vascular Center, Budapest, and Bacs-Kiksun County Hospital, Kecskemet, Hungary; and ³Faculty of Pharmacy, Laval University, Quebec, Canada.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

The authors report that patient consent was provided for publication of the images used herein.

Manuscript accepted February 26, 2020.

Address for correspondence: Olivier F. Bertrand, MD, PhD, Quebec Heart-Lung Institute, 2725, Chemin Ste Foy, Quebec (Quebec) G1V 4G5, Canada. Email: Olivier.Bertrand@fmed.ulaval.ca

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