1. Field of the Invention
The present invention is generally related to medical devices, systems, and methods. In particular, the invention provides methods and systems for delivery of energy and/or bioactive materials (i.e. bioactives) to body tissue, most preferably by selective delivery to body tissues disposed about a lumen using a catheter-based treatment system.
2. Discussion of Related Art
Physicians use catheters to gain access to, and repair interior tissues of the body, particularly within the lumens of the body such as blood vessels. For example, balloon angioplasty and other catheters often are used to open arteries that have been narrowed due to atherosclerotic disease. Balloon angioplasty is often effective at opening an occluded blood vessel, but the trauma associated with balloon dilation can impose significant injury, so that the benefits of balloon dilation may be limited in time.
Stenting procedures, in conjunction with balloon dilation, are often the preferred treatments for atherosclerosis. In stenting, a collapsed metal framework is mounted on a balloon catheter, which is introduced into the body. The stent is manipulated into the site of occlusion and expanded in place by the dilation of the underlying balloon, or in the example of a self-expanding stent, the stent scaffolds open upon release of constraint by the catheter. Stenting has gained widespread acceptance, and produces generally acceptable results in many cases. Along with treatment of blood vessels (particularly the coronary arteries), stents can also be used in treating many other tubular obstructions within the body, such as for treatment of reproductive, gastrointestinal, and pulmonary obstructions. Restenosis or a subsequent narrowing of the body lumen after stenting has occurred in a significant number of cases.
A variety of modified restenosis treatments or restenosis-inhibiting treatment modalities have also been proposed, including intravascular radiation, cryogenic treatments, ultrasound energy, and the like, often in combination with balloon angioplasty and/or stenting. While these and different approaches show varying degrees of promise for decreasing the subsequent degradation in blood flow following angioplasty and stenting, the trauma initially imposed on the tissues by angioplasty remains problematic.
A number of alternatives to stenting and balloon angioplasty have been proposed to open stenosed arteries. For example, a wide variety of atherectomy devices and techniques have been disclosed and attempted. Despite the disadvantages and limitations of angioplasty and stenting, atherectomy has not gained the widespread use and success rates of dilation-based approaches. More recently, still further disadvantages of dilation have come to light. These include the existence of vulnerable plaque, which can rupture and release materials that may cause myocardial infarction or heart attack.
More recently, drug coated stents (such as Johnson and Johnson's Cypher stent, the associated drug comprising Sirolimus) have demonstrated a markedly reduced restenosis rate, and others are developing and commercializing alternative drug eluting stents. While drug-eluting stents appear to offer significant promise for treatment of atherosclerosis in many patients, there remain many cases where stents either cannot be used or present significant disadvantages. Generally, stenting leaves an implant in the body. Such implants can present risks, including mechanical fatigue, corrosion, thrombus formation, and the like, particularly when removal of the implant is difficult and involves invasive surgery. Stenting may have additional disadvantages for treating diffuse artery disease, for treating bifurcations, for treating areas of the body susceptible to crush, and for treating arteries subject to torsion, bending, elongation, and shortening.
Information that may be relevant to proposed treatments of atherosclerotic disease can be found in U.S. Pat. Nos. 5,102,402; 5,304,121; 5,304,171; 5,306,250; 5,380,319; 5,588,962; 5,693,029; 6,389,314; 6,477,426; 6,623,453; 6,695,830; 6,706,011; 6,723,064; 6,788,977; 6,991,617; 6,958,075; 7,008,667; 7,066,904; 7,291,146; and 7,407,671, for example. Further information can be found in U.S. Patent Application Publication Nos. 2003/0069619; 2003/0229384; 2004/0062852; 2004/0243199; 2005/0203498; 2005/0251116; 2005/0283195; 2006/0235286; 2007/0278103; 2008/0125772; 2008/0140002; 2008/0161801; 2008/0188912; 2008/0188913; 2008/0262489 and 2009/0074828 as well as European Patent Application No. EP 1622531 and PCT Patent Publication Nos. WO 2005/007000 and WO 2009/121017. Scheller et al., “Potential Solutions to the Current Problem: Coated Balloon,” EuroIntervention, 2008 Aug.; 4 Suppl C: C63-66 and Tepe et al., “Local Delivery of Paclitaxel to Inhibit Restenosis During Angioplasty of the Leg,” N Engl J Med, 2008 Feb. 14; 358(7): 689-699 may also include relevant information.
Therefore, it would be advantageous to provide new and/or improved methods and systems for delivery of therapeutic treatment to diseased tissue. Ideally, these improved techniques would facilitate selectively targeting tissue for treatment through the introduction of temperature change and/or bioactives to the targeted tissue in such a way that may simplify the procedure, may reduce procedure time, may improve the therapeutic result, or any combination thereof.