FIELD OF THE INVENTION
This invention relates to perfusion catheters and, more particularly, to perfusion dilation catheters used for arterial angioplasty.
BACKGROUND OF THE INVENTION
Catheters are commonly used invasively to treat cardiovascular diseases through a method known as balloon angioplasty. A catheter is employed having a balloon portion near the catheter's distal end. The balloon portion is placed within an obstructed artery and inflated; expanding outwardly, the balloon dilates the arterial vessel.
Balloon angioplasty procedures when successful avoid bypass surgery and the attendant costs and medical risks thereof. Effective treatment of arterial stenoses, however, may not be realized through current balloon angioplasty methods for a number of reasons. For example, the lumen through the stenosis may be too narrow to permit entry of the deflated balloon catheter. Also, inflation times of currently used balloon catheters may be limited to 15 to 60 seconds due to occlusion of the arterial opening by the inflated balloon. This limited inflation time is often not sufficient to treat the stenosis and inflations must be repeated. Further, even if the arterial lumen is successfully dilated, the effect may be only temporary. Restenosis of the artery after treatment is not uncommon. It is believed, however, that a sustained inflation of the catheter balloon, rather than shorter multiple inflations, would reduce the possibility of such post-treatment restenosis.
A sustained inflation period also permits use of relatively lower inflation pressures. Extended, low pressure inflation tends to compress, rather than tear, plague of an arterial lesion over time. By not tearing the arterial lesion, healing of the dissection is facilitated. In contrast, conventional shorter multiple balloon inflations performed at relatively high inflation pressures could tear the arterial lesion thereby prolonging recovery or entirely preventing successful treatment.
SUMMARY OF THE INVENTION
The present invention comprises an improved balloon perfusion catheter that provides many advantages not afforded by conventional catheters. More specifically, the present invention provides a perfusion balloon catheter having a flexible elongated shaft, which shaft is provided with first and second lumens extending therewithin. A perfusion shaft and inflation shaft extend outwardly from, and are in communication with, the first and second lumens, respectively. A portion of the perfusion shaft has an angioplasty balloon mounted circumferentially therearound. The inflation shaft distal end is located at the balloon proximal end and therefore the inflation shaft does not enter the stenosis lumen during treatment. As the perfusion shaft with circumscribing balloon is the largest diameter portion of the catheter that need be inserted into an arterial stenosis, lesions having relatively small openings can be treated successfully.
Both proximal and distal to the balloon, the perfusion shaft has a plurality of openings which permit blood flow through the artery during balloon inflation thereby providing the advantage of longer balloon inflation time. Preferably, the openings spirally circumscribe the perfusion shaft both proximal and distal to the balloon, each opening being radially offset from each adjacent opening. Such spiral circumscription has been found to provide enhanced blood flow into and through the perfusion shaft.
The inflation shaft generally extends from the elongated shaft to the balloon at least partially separate from and without attachment to the perfusion shaft. At least partial separation of the perfusion shaft and inflation permits advantageous circumscription of the perfusion shaft by the plurality of openings.
The perfusion shaft has a distal end radiopaque marker affixed thereon near the perfusion shaft distal end, a balloon radiopaque marker affixed thereon and beneath the balloon, and a proximal end radiopaque marker affixed thereon near the perfusion shaft proximal end. A guide wire may be inserted through the first lumen and the perfusion shaft to provide means for advancing the balloon to the targeted artery.
It is an object of the invention to provide a balloon dilation catheter which permits an angioplasty procedure on a stenosis lumen, including a narrow stenosis lumen.
It is another object of the invention to provide a balloon dilation catheter which affords enhanced blood perfusion through an obstructed artery during balloon inflation.
It is a further object of the invention to provide a balloon dilation catheter which permits use of relatively long balloon inflation times and low balloon inflation pressures.