1. Field of the Invention
This invention relates generally to measurement of physical, chemical and anatomic parameters in the lung for diagnosis of pulmonary disease and localized treatment of the disease.
2. Description of the Related Art
Chronic obstructive pulmonary disease (COPD) is a significant medical problem affecting 16 million people, or about 6% of the U.S. population. Specific diseases in this group include chronic bronchitis, asthmatic bronchitis, and emphysema. Lung cancer, as another example, is among the most prevalent forms of cancer, and causes more than 150,000 deaths per year in the U.S. Many methods have been proposed and are in use for diagnosis and treatment in the advanced stages of disease progression. These stages are marked by significant damage to the lung tissue so that the difference between healthy and diseased tissue is readily apparent during the diagnosis. Typically, imaging tests such as chest x-rays, computed tomography (CT) scans, Magnetic Resonance Imaging (MRI), perfusion scans, and bronchograms provide a good indicator of the location, homogeneity and progression of the diseased tissue. However, these tests provide a diagnosis from the global (i.e., whole lung) level, rather than from the local (i.e., from the lobar or segmental) level.
Recently, the trend has been toward early diagnosis of disease conditions using a variety of new techniques. Early diagnosis of lung disease has many benefits such as increased patient wellbeing along with reduced morbidity, lowering of treatment costs, and decreased load on the health care system. Such diagnosis could depend on the identification of markers or indicators of the disease condition (Lacoma et al., Eur. Respir. Rev. 2009; 18: 112, 96-104). Biochemical markers such as nitric oxide (Brindicci et al., Eur. Respir. J 2005; 26:52-59) or peroxynitrite (Osoata et al., Chest June 2009, 135(6): 1513-1520) measured in exhaled air have been used to characterize COPD for many years, although local measurement within the lung has not been reported. The markers of disease could also be anatomical changes such as constriction of airways or tearing of alveoli, or functional changes such as changes to blood flow or air flow, all of which are local indications of disease.
Functional tests could provide good physiological indicators of disease progression. Functional testing, such as spirometry, plethysmography, oxygen saturation, and oxygen consumption stress testing, among others, is being used of late to determine the course of treatment for the patient. However, identification of appropriate markers in functional and physiological testing is difficult (Jones and Agusti, Eur Respir J 2006; 27: 822-832). Moreover, since these tests are also largely global, locating the specific, local areas of disease damage where treatment is required is challenging. Interventional measurements locally within the lung would prove more beneficial.
Some methods and devices for localized diagnosis and functional testing to identify specific areas of disease within the lung are disclosed in copending U.S. Published Patent Applications 2007/0142742, 2008/0249503 and 2008/0200797, which are incorporated herein by reference. These applications discuss the measurement of collateral ventilation at the lobar and segmental levels in patients with emphysema. The measurement of collateral ventilation is done in a minimally invasive manner by occluding the airway and determining the change in pressure and/or measuring the composition of the gas within the lung compartment. The measurements may then be followed by an appropriate treatment to effect lung volume reduction.
Measurement of collateral ventilation through the use of external pressurization is disclosed in U.S. Pat. No. 6,692,494 to Cooper et al. Disadvantages of such a technique include the possibility of additional damage to lung tissue already weakened by disease.
The use of local anatomical changes for localized treatment in asthmatic lungs is disclosed in U.S. Published Patent Application No. 2006/0254600 to Danek et al. This reference describes the measurement of several parameters such as airway diameter, airway compliance, airway inflammation, etc., that are indicative of asthma. Some of these parameters are measured after artificial stimulation by introducing an agent at the airway location, which is specific to asthma treatment. Though this reference also discusses measurement of local changes in pressure for determining the course of treatment, the specific details of the measurement technique are not disclosed.
The use of chemical markers for diagnosing lung disease is disclosed in U.S. Published Patent Applications 2006/0074282 to Ward et al. and 2007/0261472 to Flaherty et al. The 2006/0074282 reference discloses the use of Raman spectroscopy to detect biochemical markers at locations within the lung through a flexible optical conduit, or externally, in exhaled air. The biomarkers include those relevant to lung disease such as nitric oxide-hemoglobin complex. However, there is no description of a specific device used for such measurement and no localized treatment is disclosed. The 2007/0261472 reference discloses non-invasive sensing of nitric oxide in exhaled air for diagnosis of asthma-related hypoxia. However, the method uses global measurement in exhaled air and the affected portion of lung cannot be identified.
Markers and indicators of respiratory diseases can be quite complex, as there may be no universal biochemical marker or level of indication that is applicable for diagnosis of diseases such as emphysema or asthma. Clinical studies show that levels of the most commonly used biomarkers must be individualized and their changes monitored for deriving meaningful conclusions. Physiological and anatomical indications may also be required to be monitored along with biochemical markers for identifying the areas most severely affected by disease. Because of the large number of variables and the absence of unique determinants, it is not feasible for a physician to merely study the data and decide on locations requiring treatment. Partly addressing this shortcoming, U.S. Pat. No. 7,517,320 to Wibowo et al. discloses a method of using imaging data from emphysematous lungs to obtain a ranking of tissue regions for treatment. The ranking is based on parameters such as airway diameter, airway thickness, collateral ventilation, degree of tissue destruction, etc. However, these parameters are obtained only by analyzing image data and not by local measurement. Given that pulmonary disease indicators can be complex, a sophisticated approach toward multiparametric analysis of the clinical data would be more effective for diagnosis and treatment.
If diagnoses are not localized, the corresponding interventional treatments involving therapeutic agents may cause side effects that are detrimental. For example, steroids may be administered to a patient by inhalation to control asthma or emphysema. However, the dosage required for inhalation treatment is much higher than that required to locally treat an airway. In inhalation therapy, to ensure that the treatment is effective, a high concentration of the drug must be used, and the whole lung must be treated. A high proportion of the ingested drug is ineffective and simply passes through the system, producing a variety of harmful side effects due to reaction with non-diseased portions of the lung and body. Localized treatment, while being highly effective (because it introduces treatment exactly where it is needed), reduces global or systemic intake and minimizes side effects.
Some devices have sought to address this shortcoming by using localized treatment. For example, U.S. Published Patent Application 2008/0200797 (cited above) also discloses the implantation of a one-way valve in the airway at an appropriate location for effecting gradual lung volume reduction. U.S. Published Patent Application 2008/0249503 (also cited above) further discloses the use of therapeutic agents for treatment. These treatments would be enhanced by the provision of ameliorated diagnostic methods at the localized level.
The above discussion of the prior art shows that there is a need for a system that provides for local diagnosis of various parameters within a diseased lung, a better way of ranking various sites based on locally measured parameters, and a way to treat locations that are most affected by disease, in a comprehensive manner. At least some of these objectives are met by the embodiments described below.
In one aspect of the present invention, a method is described for selecting one or more treatment sites in a diseased lung. In one embodiment, the method may involve: introducing an assessment catheter into an airway leading to a first assessment site in the lung; expanding an occluding member on the catheter to form a seal with an inner wall of the airway and thus isolate the first assessment site; measuring at least one physiological, anatomical or biological characteristic of the first assessment site using the catheter; calculating a score for the first assessment site based on the measured characteristic and a predetermined algorithm; repeating the steps for at least a second assessment site in the lung; and selecting at least one treatment site based on the scores of the assessment sites. In various embodiments, the method may further include repeating the steps for at least a third assessment site, fourth assessment site, etc.
In some embodiments, at least the calculating step may be performed by a console coupled with a proximal end of the catheter, and the scores may be displayed on the console. In some embodiments, the physiological characteristic is collateral ventilation. For example, the collateral ventilation may be assessed to treat an air leak or may be assessed to select an appropriate lung segment for treatment of emphysema. In one embodiment, the biological characteristic may be nitric oxide. In one embodiment, the anatomical characteristic may be an air leak. In some embodiments, the algorithm may be based on a determined number of diseased regions in the lung, the at least one physiological, anatomical or biological characteristic of each site, and proximity of each assessment site to at least one of the diseased regions.
In some embodiments, the method may further involve treating the treatment site(s). Optionally, the method may further include introducing an assessment catheter into the lung to confirm efficacy of treatment. In one embodiment, treating the site may involve implanting a one-way flow control element into an airway leading to a portion of the lung afflicted by emphysema. In various embodiments, the flow control element may include but is not limited to a plug, a one-way valve or a two way valve. In some embodiments, the flow control element is provided with a drug depot configured to provide sustained release of a drug. For example, the drug depot may be configured to release one or more steroids and/or anticholinergics.
In other embodiments, treating may involve performing endoscopic lung volume reduction. Alternatively, treating may involve introducing a drug into the treatment site through a treatment catheter. In yet other embodiments, treating may involve performing bronchial thermoplasty. Alternatively, treating may involve installation of a chest tube.
In another aspect, a method for assessing the effectiveness of a treatment may involve identifying an airway that has been occluded with a one-way valve, where the one-way valve is configured to allow expiration but limit inhalation. The method may further include introducing a catheter into the identified airway, the catheter including a distal end, a proximal end, and a lumen therebetween. The distal end of the catheter may include an expandable occluding element configured to sealingly engage the airway, and the proximal end may include an inflation port to expand the occluding element. The lumen may be in-line with at least one sensor for measuring a respiratory characteristic. The method may further involve measuring flow through the airway to determine whether flow exists during inhalation, where the presence of flow indicates ineffective valve placement. Optionally, the method may further involve measuring pressure during inhalation, where the presence of pressure indicates ineffective valve placement.
The methods and devices described herein may be useful in diagnosis and/or treatment of diseased lungs afflicted with emphysema, cancer, asthma, air leak, or any of a number of other lung ailments.
The invention has other advantages and features which will be more readily apparent from the following detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawings, in which:
Although the detailed description contains many specifics, these should not be construed as limiting the scope of the invention but merely as illustrating different embodiments. Thus, the scope of the invention may include other embodiments not discussed in detail. Various other modifications, changes and variations may be made in the arrangement, operation and details of the methods and systems of the embodiments disclosed herein without departing from the spirit and scope of the invention as described.
Methods for treating lung disease according to some embodiments may involve inserting a catheter into the lung to make local measurements of one or more characteristics associated with disease progression. The measurement data is collected for one or more locations within the lung. If several locations are measured within the lung, an evaluation parameter is derived from the measurement data related to the disease progression at the locations. The disease progression is then visualized in a geometrical representation of the lung, and suitable treatment is delivered at the visualized locations.
In each of the present embodiments, isolation of the lung comprises sealingly engaging a distal end of a catheter in an airway feeding a lung compartment, as shown in
In one aspect of the invention, catheter 100 is introduced into the target lung compartment TLC which is isolated by inflating the occlusion element 120. Thereafter, a physiological, anatomical or biological characteristic is assessed at the location in the TLC. For purposes of description, the measurements obtained by the catheter are described as being of the TLC. It should be understood, however, that such a description includes the TLC, the airway between catheter and TLC and any similar anatomy.
The proximal end of the catheter 100 is configured to be associated with a console 200, which is shown in
The various steps in one embodiment of the invention are illustrated in the schematic flow diagram shown in
In step B, data or measurements of a local parameter (which includes anatomical, physiological or biological characteristics) are obtained from the assessment site. In step C, the characteristic data collected by the sensors, which relate to the state of disease progression at different locations within the lung, are collected along with the corresponding positional (anatomical) information. The information is collected within a database that is stored within a system with processor and memory attached or contained within the console. Steps B and C are repeated across a number of sites in the patient's lung as required. Thereafter, in step D, the collected data is then used to derive a score corresponding to each measurement site. The score may be a suitable function of the anatomical, physiological and biological characteristics measured and optionally may indicate an order of priority for treatment. A functional algorithm is used to derive the score and the algorithm may vary depending on the lung disease being treated. The scores, which are indicative of the severity of the disease at different locations within the lung, are then displayed on the console for viewing, for example in graphical form or as an anatomical representation.
Thereafter, the identified diseased portions may be treated as shown in step E. Treatment may be optimized by the aforementioned scoring, which may score the sites according to a feature such as a site's geometrical location or the state of disease progression. The disease may then be treated by delivering a therapeutic agent at one of the assessment sites. Alternatively, the lung compartment may be treated by deploying a device such as a flow restrictor at the airway location.
An exemplary physiological characteristic is the presence and/or degree of collateral ventilation which can be measured using any of the methods disclosed in copending U.S. Patent Applications 2003/0051733 and 2006/0264772. An exemplary biological characteristic is the presence of a gas such as nitric oxide, which is often found in diseased lung segments. An exemplary physiological characteristic is the presence of an air leak, which may also be determined by measurements of collateral ventilation.
In another aspect of the present invention, the locations or positions of the assessment sites are recorded or tracked. The locations of the sites are thereafter mapped into a computerized database located within the system attached to console 200. The data measured by sensors 140 and the position data are then used to calculate a ranking parameter for prioritizing treatment. The ranking parameter is obtained using an algorithm based on the determined number of diseased regions in the lung, one or more of the physiological, anatomical or biological characteristics of each site, and proximity of one or more assessment sites to at least one of the diseased regions.
Another aspect the invention involves determining a treatment plan based on the ranking of various sites within the lung and the disease state of the patient. The treatment plan may include determining which sites are to be treated first based on anatomical location or the progression of the disease. Thereafter, the assessment site may be treated in a number of ways using the treatment plan. The specifics of the treatment may depend upon the disease and may include installation of flow control elements such as a plug, a one-way valve, a two-way valve, or a two-way valve fitted with a drug depot. Alternatively, minimally invasive surgical sealing of the airway or surgical lung volume reduction may be practiced. Additionally and optionally, treatment may further include delivering a therapeutic agent to the TLC. The therapeutic agent can be in solid, liquid, gel or vapor form, and may be administered according to a treatment plan.
In one embodiment, if the degree of collateral ventilation is small or negligible in a patient with COPD such as emphysema, the treatment may involve lung volume reduction as shown in
Alternatively, as shown in
In alternative embodiments, the airway can be surgically sealed by suturing, for example. The sealing may be accompanied by active methods of lung volume reduction such as endobronchial aspiration or externally forcing air out of the TLC through surgical means.
In another embodiment, an airway bypass may be produced by creating an artificial opening between the affected portion of lung and the healthy portion to effect lung volume reduction. The airway bypass may be provided by installing a one-way flow control element across the bronchial wall.
In another embodiment of the invention shown in
In another embodiment shown in
The use of drugs may be particularly useful in treatment of diseases such as lung cancer, wherein general systemic exposure to the agent may be undesirable, while high concentrations may be required to be delivered on a sustained basis to the disease location. The method of the present invention as disclosed in
In another embodiment, the invention may be used for the treatment of asthma. The endobronchial catheter 100 shown in
Another treatment option is the use of a tissue prosthesis or a chest tube to treat a bronchopleural leak. The tissue prosthesis may be made of any suitable biosorbable material.
In all the above embodiments the efficacy of treatment may be confirmed by introducing an assessment catheter to confirm the reduction of a disease marker parameter. For example, the catheter may be used to determine if any air leaks exist post-procedure so that subsequent treatment options may be assessed. Further, the catheter can be used to quantify the effectiveness of drug therapy, valve placement or the sealing agent at the local level.
The particular example of using the catheter to determine the effectiveness of valves or other implants designed to induce ELVR is shown in
It should be noted that the above example can also be used to determine the presence of physiological air leaks occurring in an untreated lung as a diagnostic tool prior to any treatment at all. The same process is used, and a similar graph to Graph c would be obtained if the lung compartment contained any inherent air leaks.
While the above is a complete description of various embodiments, various alternatives, modifications, and equivalents may be used. Therefore, the above description should not be taken as limiting the scope of the invention, which is defined by the appended claims.
This application claims the benefit of Provisional Application No. 61/289,848 (Attorney Docket No. 017534-007600US), filed on Dec. 23, 2009, the full disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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61289848 | Dec 2009 | US |