Surgery – Instruments – Light application
Reexamination Certificate
2001-05-29
2003-07-15
Peffley, Michael (Department: 3739)
Surgery
Instruments
Light application
C606S001000, C606S010000
Reexamination Certificate
active
06592576
ABSTRACT:
The invention relates to a system for performing myocardial revascularization on a beating heart of a patient.
Transmyocardial revascularization (TMR) is a surgical treatment for cardiovascular disease. Present TMR procedure uses a laser beam to drill holes of approximately 1 mm diameter through the myocardium, typically into the left ventricle. These holes or channels extend through the entire heart wall thickness from the outside through to the ventricle. The openings of the channels on the outside surface of the heart heal due to external pressure from the surgeon, but the channels remain open on the inside, allowing blood to enter the heart wall tissue from the ventricle.
In another approach myocardial revascularization can be performed using a catheter introduced percutaneously so that the tip of the catheter is inside a chamber of the heart, typically the left ventricle, where the holes or channels can be created from the inside toward but not through the outside of the heart. This approach is also known as endocardial laser revascularization (ELR), percutaneous myocardial revascularization (PMR), and direct myocardial revascularization (DMR). The channels are drilled with a laser beam introduced through the catheter. The catheter typically is an 8-French or 9-French catheter.
Certain problems are presented when laser revascularization is done on a beating heart. A beating heart presents a moving target, which can make it difficult to accurately and consistently form channels of a desired depth and size. The heart also is extremely sensitive to a laser pulse at certain times during its cycle. A laser pulse striking the heart during the T wave of the heart beat cycle could cause the heart to fibrillate and result in complications. While one could stop the heart during the process of TMR, this poses other risks to the patient and complicates the operating procedure. The heart must be cooled and the patient connected to a heart-lung machine.
However, the risk of inducing a beating heart to fibrillate is greatly reduced when the laser is fired only during the refractory period of the heart cycle between the R and T waves of the ECG signal. An additional benefit of firing the laser only between the R and T waves is that this is the period of the heartbeat cycle during which the heart is most still and channels can be formed most accurately. Rudko U.S. Pat. No. 5,125,926 describes a heart-synchronized pulsed laser system that fires a laser only during the refractory period of the heartbeat cycle. The patent describes an open chest procedure using an articulated optical arm or a fiber optic element to deliver the laser beam to a surface of the heart.
Aita U.S. Pat. No. 5,389,096 discloses a percutaneous myocardial revascularization procedure in which a steerable heart catheter is guided from the femoral artery via the abdominal artery into the left ventricle. The laser energy is delivered through the working channel of the catheter by a fiber optic delivery system.
SUMMARY OF THE INVENTION
In one aspect, the invention features, in general, a myocardial revascularization system that includes a laser energy source, an outer guide member providing access to a patient's heart, and an optical fiber. The optical fiber is coupled to receive laser energy pulses from the source, is slidably located within the guide member, and is extendible from the distal end of the guide member. A drive motor is connected to the fiber to automatically move the distal end of the optical fiber with respect to the distal end of the guide member. A controller controls the drive motor to automatically move the fiber in synchronism with firing of the laser energy.
In another aspect, the invention features, in general, a myocardial revascularization system that includes a laser energy source, an outer guide member providing access to a patient's heart, an optical fiber that is slidably located within the guide member, and a drive motor connected to the fiber to automatically move the distal end of the optical fiber with respect to the distal end of the guide member. A controller controls the drive motor and automatically calibrates the position of the distal end of the fiber with respect to the distal end of the catheter.
In another aspect, the invention features, in general, a myocardial revascularization system that includes a semiconductor laser energy source (e.g., a diode laser) that outputs laser pulses having a wavelength between 600 nm and 1000 nm, an optical fiber that is coupled to receive laser energy pulses from the source and to deliver them to a patient's heart tissue to be revascularized, and an outer guide member that engages the fiber and permits an operator to direct the tip to contact the patient's heart tissue to be revascularized.
In another aspect, the invention features, in general, a myocardial revascularization system that includes a laser energy source, an optical fiber that is coupled to receive laser energy pulses from the source and to deliver them to a patient's heart tissue to be revascularized, and an outer guide member that engages the fiber and permits an operator to direct the tip to contact the patient's heart tissue to be revascularized. The fiber has, at its tip, a heat absorbing material that is nonmetallic and is partially transparent to the pulses.
In another aspect, the invention features, in general, a myocardial revascularization system that includes a laser energy source, an optical fiber that is coupled to receive laser energy pulses from the source and to deliver them to a patient's heart tissue to be revascularized, and an outer guide member that engages the fiber and permits an operator to direct the tip to contact the patient's heart tissue to be revascularized. The fiber has an enlargened portion at the tip thereof that has a transverse dimension that is larger than the fiber diameter.
In another aspect, the invention features, in general, a myocardial revascularization system that includes a laser energy source, an outer guide member providing access to a patient's heart, and an optical fiber that is coupled to receive laser energy pulses from the source and is slidably located within the outer guide member. The outer guide member is 7 French or smaller and has a deflectable distal end that is deflectable by an operator-controlled mechanism.
In another aspect, the invention features, in general, a myocardial revascularization system that includes a laser energy source, an outer guide member providing access to a patient's heart, and an optical fiber that is coupled to receive laser energy pulses from the source and is slidably located within the outer guide member. A lubricant is located between the optical fiber and an inner lumen surface of the guide member.
In another aspect, the invention features, in general, a myocardial revascularization system that includes a laser energy source, an outer guide member providing access to a patient's heart, and an optical fiber that is coupled to receive laser energy pulses from the source and is slidably located within the outer guide member. A first position sensing component is carried by the optical fiber at or near the distal end of the fiber, and a second position sensing component is carried by the guide member at or near the distal end of the guide member.
In another aspect, the invention features, in general, a myocardial revascularization system that includes a laser energy source, an outer guide member providing access to a patient's heart, and an optical fiber that is coupled to receive laser energy pulses from the source and is slidably located within the outer guide member. The guide member has a distal end having a non-slip structure for engaging a surface location of a patient's heart tissue.
In another aspect, the invention features, in general, a percutaneous myocardial revascularization system that includes a laser energy source, a catheter for percutaneous access to a patient's heart, an optical fiber that is coupled to receive
Andrews Robert R.
DeSantis Italo J.
Gronek Weslaw
Rudko Robert I.
Yeomans, Jr. Richard P.
Fish & Richardson P.C.
Peffley Michael
PLC Medical Systems, Inc.
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