GASTRIC BANDING SYSTEM ADJUSTMENT BASED ON A SATIETY AGENT CONCENTRATION LEVEL

Methods and devices are provided for adjusting a gastric band to obtain a predetermined optimal expression of hormones. These hormones may be used to control appetite, metabolism and other weight control mechanisms. Ultimately, weight-loss efficacy is desired by tightening or loosening the gastric band based on hormone response.

DETAILED DESCRIPTION

The present disclosure generally provides adjustable gastric banding systems, for example, for treatment of obesity and obesity related conditions, as well as systems for controlling inflation of a gastric banding system based on a measured physiological response to the adjustment of the gastric band.

Persons skilled in the art will readily appreciate that various aspects of the disclosure may be realized by any number of methods and devices configured to perform the intended functions. Stated differently, other methods and devices may be incorporated herein to perform the intended functions. It should also be noted that the drawing FIGS. referred to herein are not all drawn to scale, but may be exaggerated to illustrate various aspects of the invention, and in that regard, the drawing FIGS. should not be construed as limiting. Finally, although the present invention may be described in connection with various medical principles and beliefs, the present invention should not be bound by theory.

By way of example, the present disclosure will reference hydraulically adjustable gastric bands. Nevertheless, persons skilled in the art will readily appreciate that the present disclosure advantageously may be applied to one of the numerous varieties of fluid filled surgical implants presently comprising, or which may in the future comprise, access ports. Similarly, while the present invention will be described primarily with reference to fluid filled surgical implants, persons skilled in the art will readily appreciate that the present invention advantageously may be applied to other devices, and whether fluid or gel filled.

Referring toFIG. 1A, a gastric band10in accordance with the present disclosure includes a body portion11with an inner stomach-facing surface15. The body portion11has a head end12and a tail end or “belt”13. A fill tube14, which is generally a tube having a single lumen coextensive therewith, is in fluid communication with an inflatable chamber16(also can be referred to as an inflatable member or an inflatable portion) on the inner surface15of the band body11. Preferably, the inflatable chamber16is substantially coextensive with the inner surface15of the body portion11. The central lumen of the fill tube14is in fluid communication with the inflatable chamber16. The head end12of the body portion11has a “buckle”19through which the tail end of “belt”13is inserted and locked in place in use. The head end12may be provided with a pull tab18for use in locking the band in place about the stomach.

In use, the gastric band10is placed in an encircling position around the stomach and locked in place as shown inFIG. 1B(InFIG. 1B, the stomach is omitted for clarity.). This is accomplished by introducing the gastric band10through a laparoscopic cannula (not shown) in a patient's abdominal cavity. The laparoscopic placement includes blunt dissection below the gastro-esophageal junction followed by placement of the gastric band10. The end of the fill tube14is passed through the dissected path around the upper stomach, and the tail end or belt13is passed through the buckle19, so that the belt13and the buckle19lock in place. A laparoscopic closure tool, such as that disclosed by Coe and Vincent in U.S. Pat. No. 5,658,298, incorporated herein by reference, may be used. Hence, with the gastric band10affixed in an encircling position around the stomach, a new stoma (opening) is created within the stomach. After the gastric band10is secured in position, the size of the stoma may be adjusted by adding fluid to or withdrawing fluid from the inflatable chamber16to bring the stoma opening to the desired size. The inflatable chamber16is preferably coextensive with the inner stomach-facing surface15of the gastric band10between the head end12and the tail end13. The interior of the adjustable chamber16is in fluid communication with a fluid reservoir (not shown) by means of the central lumen of the fill tube14, as with prior art adjustable gastric bands. The inflatable chamber16is gradually inflated or deflated with saline or other biologically compatible fluid via the fluid reservoir such that the inflatable chamber16presses on and constricts the stomach wall or other tissue underlying the gastric band10. This results in the decrease or increase of the size of the stomach opening directly inside the encircling gastric band10.

FIG. 2illustrates a flow chart of a method of determining whether a patient is at or near an optimal hormone concentration level. At step201, the gastric band (e.g., the gastric band10ofFIG. 1A) is adjusted to form a tighter constriction about the stoma. In one example, tightening the gastric band about the stoma may be performed by adding fluid to the gastric band. At step202, a period of time may be observed so that the impact of the tightening of the gastric band may be reflected by the collection of the fluid sample at step203(e.g., collecting of a blood sample from the patient). The sample may be obtained using one of a number of traditional fashions such as by pricking the patient's finger, using a needle inserted subcutaneously into the patient's vein, and the like. The amount of blood to be collected may vary from a drop or two to a few cubic centimeters. At step204, the blood sample may be measured to determine the level of concentration of a particular satiety-inducing agent such as a hormone. At step205, the measured concentration level of the satiety-inducing agent obtained from the patient's blood may be compared to a pre-determined level. In one embodiment, the pre-determined level of concentration may be based on a combination of the patient's personal data including historical levels previously gathered and general population data such as an average hormone level for a category that the patient is within (e.g., based on sex, ethnicity, height, weight, body mass and the like). The result of the comparison step of205may be used to determine whether the tightening of the band in step201results in optimal hormone levels.

In one embodiment, the adjustment of the band is performed in conjunction with the patient eating a meal. In this manner, the hormone response to the tightening of the gastric band may indicate whether the patient is still hungry after eating the meal or whether the patient feels full or satiated.

As discussed herein, a predetermined amount of time may be any period of time ranging from 5 minutes to multiple hours (e.g., 15 minutes, 30 minutes, 1 hour, 2 hours and the like). However, in one embodiment, the predetermined time might be the amount of time a particular person takes to release hormones in response to eating food and adjustment of the gastric band. In the average patient, the period of time may be 30 minutes, however, this may be customizably adjustable by a physician to best suit the particular patient. In one embodiment, the hormone response may be monitored continuously during a first visit after a patient consumes a meal/tightening of the gastric band in order to determine the appropriate period of time. In another embodiment, the predetermined amount of time may correlate with the specific hormone the physician is testing for. In one example, GLP-1 may be released about 10-15 minutes after the band is tightened, while oxyntomodulin might not be released until about 90-150 minutes after the tightening.

Turning toFIG. 3, a flow chart of a method for determining whether a patient is at or near an optimal hormone concentration level is provided. At step301, a gastric band attached to a patient is adjusted at the time coincidental to, immediately after, or immediately prior to the patient having a meal. At step302, a fluid-sample is obtained (e.g., a blood sample) from the patient after the passing of a predetermined period of time. At step303, the fluid sample may be measured to determine the concentration level of one or more satiety-inducing agents (e.g., hormones). At step304, a comparison is made to ascertain whether the determined concentration levels are within a target range. If so, the records corresponding to the patient may be updated to detail the adjustment made in step301and the resulting concentration level of the one or more satiety inducing agents. However, if the result of the comparison of step304lies outside the target range, the process may revert back to step301and the gastric band may be re-adjusted. In one embodiment, re-adjustment of the gastric band may be based on the physiological response (e.g., the concentration level of the hormones) alone or the re-adjustment of the band may be based upon a combination of the physiological response and verbal feedback from the patient.

FIG. 4illustrates a flow chart of another method of determining whether a patient is at or near an optimal hormone concentration level. At step401, a first fluid sample may be obtained from the patient (e.g., blood sample). At step402, the gastric band (e.g., gastric band100) may be adjusted. In one embodiment, the adjustment of the gastric band is performed in conjunction with the patient eating a meal. At step403, a second fluid sample may be obtained from the patient. At step404, a difference in a concentration level of one or more satiety-inducing agents between the first sample and the second sample is determined. At step405, the difference is compared to a target range. If the difference is within the target range, patient records may be updated to reflect hormone levels and the band adjustment details in step406. However, if the difference is not within the target range, the process may return to step402, and the gastric band may be re-adjusted. In one embodiment, the process may be repeated until the hormone levels differences are within an acceptable range or until the patient indicates discomfort. Alternatively, re-adjustment of the gastric band may be delayed until the next patient meal.

In another embodiment, for situations where it appears that the patient might not be able to produce the optimal amount of hormones with adjustment of the gastric band for reasons such as discomfort with the tightness of the gastric band or other physiological reasons, the gastric band may be configured to release the hormone in order to raise the patient's hormone level to the optimal hormone level. Methods for configuring the gastric band to release such hormones are disclosed in Raven, U.S. patent application Ser. No. 12/771,671, herewith incorporated in its entirety. In one embodiment, the physician may calculate the deficiency of hormone level and configure the band to release an amount equal to the deficiency.

Some embodiments described herein are directed to the scenario where collection of the fluid sample and determination of the hormone level is performed with the assistance of a physician or other medical personal (e.g., in obtaining the blood sample or running a test to determine hormone level). However, utilization of a sensor may replace the need to perform the aforementioned steps by the physician or medical personal.FIG. 5is a block diagram of one possible sensor which may be used in conjunction with the methods described herein.

FIG. 5illustrates a hormone-sensing device500with a housing510, a sensor520attached to a surface of the device500coupled to a processor530and a memory540. The processor530and the memory540may be coupled to a transceiver550. The sensor520may be configured to determine a concentration level of one or more hormones in the patient and pass along that information for storage in the memory540. The device500may be powered by a battery (not shown) or alternatively via any one of a number of known powering methods. One such method may involve an antenna and/or a rectifier device which receives electromagnetic radiation from an external source and delivers electrical power derived therefrom. A detailed explanation of these and other power delivering methods may be found described in U.S. Pat. No. 6,682,480 issued to Habib et al., herein incorporated by reference. The processor530may be configured to instruct the sensor520and may further be configured to execute instructions stored in the memory540. The memory540may be a physical memory such as Read-Only Memory (ROM) or any other known storage device. The processor530may further be configured to receive or send instructions (and/or other data) to and from the transceiver550. The transceiver550may be configured to transmit and receive signals from a source outside the patient's body, such as a computer, and may be further configured to relay these signals to the processor530. In one embodiment, the processor530may be further configured to instruct the gastric band to release hormones (if necessary).

By utilizing the hormone-sensing device500, a physician may be able to obtain or collect data from a sample in accordance with one or more embodiment herein without invasively using a needle and/or syringe or other traditional techniques.

In one embodiment, the sensor may be placed remotely from the gastric band system and may communicate wirelessly with the gastric band system and/or an external computer.FIG. 6depicts a schematic view of a gastric band system in communication with a sensor located in the patient's arm and a computer system external to the patient's body. In this example, the sensor may be a stand-alone device and may be embedded subcutaneously in the patient's body. In one embodiment, the sensor measures the hormone level by analyzing the interstitial fluid. In another embodiment, the sensor may have access to blood within the patient's body and may determine hormone levels and the like by analyzing the concentrations of hormones in the blood.

As shown inFIG. 6, the hormone sensor device500may be placed in the upper torso of the patient beneath the skin. The sensor device500may, in one embodiment, obtain hormone levels of particular hormones, and may relay that information with the external computer600. In addition, the sensor500may communicate with the gastric band100and may instruct the band100to either tighten or loosen based on the hormone levels detected.

In another embodiment, the hormone sensing device500may be part of the gastric band system, for example, attached to an electronically enhanced access port. In one embodiment, the hormone sensing device500ofFIG. 5may be attached to an implanted access port, such as the implanted access port disclosed in U.S. Patent Application No. 61/330,266 (App. '266), herein incorporated by reference in its entirety. For example, the hormone sensing device500may be integrated into the access port depicted in FIG. 3B of App. '266. In one embodiment, redundant components may be removed. Alternatively, the entire sensor may be attached to an outside surface of the access port shown in FIG. 1A of App. '266.

As discussed above, the methods described herein may be performed in conjunction with the hormone sensing device500described above. For example, referring toFIG. 4, the hormone sensing device500ofFIG. 5may be utilized at step401to analyze interstitial fluid within a patient to gather hormone concentration levels. At step402, the gastric band (e.g., gastric band100) may be adjusted. In one embodiment, the adjustment of the band is performed in conjunction with the patient eating a meal. At step403, the hormone sensing device500ofFIG. 5may be further utilized to re-analyze interstitial fluid within the patient to gather hormone concentration levels after the passage of a predetermined amount of time. At step404, a difference in a concentration level of one or more satiety-inducing agents between the first sample and the second sample may be determined by the hormone sensing device500ofFIG. 5. At step405, the difference is compared to a target range stored in the hormone sensing device500ofFIG. 5. If the difference is within the target range, the hormone sensing device500ofFIG. 5may transmit the relevant data to an external computer and patient records may be updated to reflect hormone levels and the band adjustment details in step406. However, if the difference is not within the target range, the process may return to step402, and the hormone sensing device500may communicate with the gastric band inside the patient to either tighten or loosen based on the measured hormone level differences. In one embodiment, the process may be repeated until the hormone levels differences are within an acceptable range or until the patient indicates discomfort. Alternatively, re-adjustment of the gastric band may be delayed until the next patient meal. In another embodiment, the external computer may be configured to control the execution of the hormone sensor device500ofFIG. 5. For example, in the instance where a patient complains about the tightness of the gastric band, the external computer may instruct the sensor to stop communication with the gastric band, or alternatively instruct the sensor to command the gastric band to loosen.

Turning to the satiety-inducing agents (e.g., hormones) discussed herein, one or more of these satiety-inducing agents may be useful in assisting a patient to lose weight. For example, these hormones include: GLP-1, PYY, PP, OXM, Amylin, Ghrelin, Leptin, Gastrin, CCK, among others.

In one embodiment, tightening of the gastric band contemporaneous with the patient eating a meal may have a direct impact on the level of hormone production in the patient. More particularly, tightening of the gastric band (and thus forming a smaller stoma) may trigger a production and/or release of hormones in the patient. However, it should be noted that either tightening the band or eating a meal alone might not result in the desired response of increased hormone production. Similarly, mere tightening of the band and the patient consuming food might also not result in the response of the desired hormone production level. In other words, the magnitude of the tightening of the band may be more important with respect to reaching the optimal level of satiety-inducing hormone production than mere tightening of the gastric band without regard to magnitude. Hence, by using one or more of the methods described herein, improved weight-loss efficacy may be achieved.

In one embodiment, a tightening of the gastric band beyond a certain threshold may trigger an acute, bimodal increase in GLP-1 production providing the patient with increased feeling of satiety be delaying gastric emptying, contributing to the ileal brake. Accordingly, in one embodiment, the hormone level for GLP-1 may be checked to ensure that an increase in GLP-1 production is, indeed, triggered by the tightening of the gastric band. If not, the gastric band may be further tightened until the acute increase is obtained.FIG. 7Aillustrates an example of a model of an acute, triggered GLP-1 response. As shown, GLP-1 levels may increase to a first peak as soon as 10 minutes after the meal and the gastric band tightening, and a second peak roughly 30 minutes after the meal and the gastric band tightening.

In one embodiment, a tightening of the gastric band beyond a certain threshold may trigger an acute, bimodal increase in PP production providing the patient with increased feeling of satiety. More particularly, PP production in humans functions to decrease appetite and food intake, independently of gastric emptying. Accordingly, in one embodiment, the hormone level for PP may be checked to ensure that an increase in PP production is, indeed, triggered by the tightening of the gastric band. If not, the gastric band may be further tightened until the acute increase is obtained.FIG. 7Billustrates an example of a model of an acute, triggered PP response. As shown, PP levels may increase to a first peak around 15-20 minutes after the meal and the gastric band tightening, and a second, albeit, significantly lower peak roughly 45-60 minutes after the meal and the gastric band tightening.

In one embodiment, a tightening of the gastric band beyond a certain threshold may trigger an acute, unimodal increase in PYY production providing the patient with an increased feeling of satiety. More particularly, PYY delays gastric emptying, contributing to the ileal brake. Accordingly, in one embodiment, the hormone level for PYY may be checked to ensure that an increase in PYY production is, indeed, triggered by the tightening of the gastric band. If not, the gastric band may be further tightened until the acute increase is obtained.FIG. 7Cillustrates an example of a model of an acute, triggered PYY response. As shown, PYY levels may increase to a peak as soon as an hour after the meal and the gastric band tightening.

In one embodiment, a tightening of the gastric band beyond a certain threshold may trigger an acute, unimodal increase in OXM production providing the patient with an increased feeling of satiety. More particularly, OXM lessens hunger and single-meal food intake. Accordingly, in one embodiment, the hormone level for OXM may be checked to ensure that an increase in OXM production is, indeed, triggered by the tightening of the gastric band. If not, the gastric band may be further tightened until the acute increase is obtained.FIG. 7Dillustrates an example of a model of an acute, triggered OXM response. As shown, OXM levels may increase to a peak as soon as 90 minutes after the meal and the gastric band tightening.

In one embodiment, a tightening of the gastric band beyond a certain threshold may trigger an acute, unimodal increase in CCK production providing the patient with increased feeling of satiety by decreasing meal size. Accordingly, in one embodiment, the hormone level for CCK may be checked to ensure that an increase in CCK production is, indeed, triggered by the tightening of the gastric band. If not, the gastric band may be further tightened until the acute increase is obtained.FIG. 7Eillustrates an example of a model of an acute, triggered CCK response. As shown, CCK levels may increase to a peak as soon as 30 minutes after the meal and the gastric band tightening.

In one embodiment, a tightening of the gastric band beyond a certain threshold may trigger an acute, unimodal increase in amylin production providing the patient with increased feeling of satiety. More particularly, amylin functions to decrease meal size and food intake. Accordingly, in one embodiment, the hormone level for amylin may be checked to ensure that an increase in amylin production is, indeed, triggered by the tightening of the gastric band. If not, the band may be further tightened until the acute increase is obtained.FIG. 7Fillustrates an example of a model of an acute, triggered amylin response. As shown, amylin levels may increase to a peak slightly less than 30 minutes after the meal and the gastric band tightening.

In another embodiment, tightening of the gastric band contemporaneous with the patient eating a meal may have a direct impact on the level of ghrelin production in the patient. Ghrelin, an acylated peptide produced primarily by the stomach and proximal small intestine, functions oppositely to satiation peptides. As such, it may be a problematic hormone in fighting obesity. In other words, ghrelin increases food intake by increasing the number of meals initiated, without altering their size, and it elicits numerous appetitive feeding behaviors.

As such, it may be advantageous to decrease the amount of ghrelin production for the sake of fighting obesity. Advantageously, the tightening of the gastric band (and thus forming a smaller stoma) may trigger a decrease in the level of ghrelin in the patient. However, it should be noted that either tightening the band or eating a meal alone might not result in the desired response of decreased production of ghrelin. Similarly, mere tightening of the gastric band and the patient consuming food might also not result in the response of the desired concentration level of ghrelin. In other words, the magnitude of the tightening of the gastric band may be more important with respect to reaching the optimal decreased level of ghrelin production than mere tightening of the gastric band without regard to magnitude. Hence, by using one or more of the methods described herein, improved weight-loss efficacy may be achieved. In one embodiment, a tightening of the gastric band beyond a certain threshold may trigger an acute, reverse unimodal decrease in ghrelin production.FIG. 7Gillustrates an example of a model of an acute, triggered ghrelin response. As shown, ghrelin levels may decrease to a valley at about 30 minutes after the meal and the gastric band tightening.

As shown inFIGS. 7A-7G, the x-axis labeled “time (minutes)” may include two numbers since different individuals may have different hormone response times depending on a variety of factors such as caloric load and carbohydrate/protein/fat ratio. For example,FIG. 7Ashould be read as “10”, “16.6”, “23.3” and “30” for a low end range (e.g., individuals with fast hormone response times) and “15”, “30”, “45” and “60” for a high end range (e.g., individuals with slower hormone response times). In other words, one individual with a fast hormone response time may release GLP-1 as quick as 10 minutes after the meal and again at 30 minutes after a meal as shown by the peaks ofFIG. 7A, whereas a second individual with a slow hormone response time may release GLP-1 as slow as 15 minutes after a meal and again at 60 minutes after a meal as shown by the peaks ofFIG. 7A. Various tests may be used by physicians to determine whether an individual has a slow response time or a fast response time (or somewhere in-between). Alternatively, a sensor (e.g., sensor520ofFIG. 5) may be used to determine when a patient has the “hormone spikes” ofFIG. 7Ato determine if the patient has a fast hormone response time or a slow hormone response time.

With respect toFIG. 7G, describing the effects of ghrelin, the same principle described above applies to the y-axis indicting ghrelin serum levels. Ghrelin serum levels may depend on the severity of obesity of the patient and the weight loss state. As such, as shown inFIG. 7G, some individuals may decrease in ghrelin from 40 pg/ml down to a valley of 20 pg/ml while other individuals may decrease in ghrelin from 700 pg/ml to 400 pg/ml.

In another embodiment, different tightening magnitudes may correspond with optimal levels of different hormones in different individuals. In other words, the optimal level for a particular person may be unique and based on one or more other factors such as age, weight, sex, height and the like. However, as an example, for an obese person having a BMI of 30 or greater, the optimal level for GLP-1 would be slightly below 30 pmol/L as shown inFIG. 7A. So, if peak levels for GLP-1 as measured after adjustment of the gastric band for an average person is substantially below 30 pmol/L (e.g., 10-15 pmol/L), tightening of the gastric band may be needed. Conversely, a concentration level of greater than 60 pmol/L of GLP-1 may cause nausea in the patient and may require loosening of the gastric band as an attempt to lower the concentration level of GLP-1 towards the optimized levels. Similarly,FIGS. 7B-7Gillustrate optimal concentration levels for the respective satiety hormones at the peaks (and valley for ghrelin). And analogous to the example discussed above with respect to GLP-1, if the peak levels for the respective satiety hormones as measured after adjustment of the gastric band for an average person is substantially below the optimal levels, tightening of the gastric band may be needed. Conversely, a concentration level significantly greater the respective peak levels may cause nausea or other discomfort in the patient and may require loosening of the gastric band as an attempt to lower the concentration level. Notably for ghrelin, as shown byFIG. 7G, the gastric band may be tightened to lower the concentration level down to the desirable valley, and the gastric band may be loosened to raise the concentration level if the ghrelin levels are significantly lower than the valley as shown inFIG. 7G.

In one example, a patient visit schedule may be used in conjunction with any of the methods described herein. For instance, a first patient-check-up visit to determine whether adjustment to the band is necessary may occur roughly 4 weeks after surgery to implant the gastric band. Follow-up visits may be scheduled every 4 to 8 weeks thereafter and may begin to taper off at 6 months, with 6 and 12 month follow-up visits thereafter. More particularly, one example of a patient visit schedule may be as follows. First visit at 4 weeks after band implant, the second visit at 8 weeks after implant, third visit at 12 weeks after implant, fourth visit at 20 weeks after implant, fifth visit at 28 weeks after implant, sixth visit at 52 weeks after implant, and an adjustment every 52 weeks thereafter.

In one embodiment, during patient visits, the sensor, if used, may be tested to determine whether the sensor is working properly. In another embodiment, the gastric band may be re-configured (if necessary) to contract and loosen based on a schedule coinciding with when the patient is usually eating in order to achieve the optimal hormone response desired (e.g., the patient reports eating at later times in the day, so the gastric band may be reconfigured to tighten to a predetermined constriction between 9:00-10:00 AM, 2:00-3:00 PM and 7:00-8:30 PM daily in order to coincide with patient meal consumption times as opposed to a previously configured constriction between 8:00-9:30 AM, 12:00-1:00 PM and 5:45-7:00 PM).

While certain hormone responses have been described herein, they are merely examples. Indeed, for any particular hormone impacting appetite and weight-control, a gastric band adjustment may result in a chronic increase, an acute increase, a chronic decrease or an acute decrease. In addition, the increase or decrease in concentration level may follow any one of the following models: a unimodal model, a bimodal model, a polimodal model, a sigmoidal model, a reverse sigmoidal modal and a logarithmic model.

Furthermore, references may have been made to patents and printed publications in this specification. Each of the above-cited references and printed publications are individually incorporated herein by reference in their entirety.