Indications, Contraindications and Cautions
The Inoue-Balloon Catheter is indicated for Percutaneous Transvenous Mitral Commissurotomy in patients with hemodynamically significant mitral valvular stenosis resulting primarily from commissural fusion of the mitral valve cusps. An echocardiographic study should suggest that balloon commissurotomy is the appropriate procedure for improving the patient’s symptoms and hemodynamic status. The PTMC procedure is one of several methods for treating symptomatic mitral stenosis. Alternative methods, which may be considered, are medical therapy, surgical commissurotomy, mitral valve repair and mitral valve replacement.
Echocardiographic study should suggest that balloon commissurotomy is the appropriate procedure for improving the patient’s symptoms and hemodynamic status. A necessary element of pre-procedure evaluation is the transesophageal echocardiogram, which will determine the presence of left atrial thrombus. Additionally, in patients felt to be at high risk for embolic events, such as patients with pre-existing atrial fibrillation, the risks of anticoagulation therapy (such as uncontrolled bleeding) before and during the PTMC procedure should be weighed against the potential benefits. It is recommended that the patient’s coagulation status be evaluated carefully prior to the procedure.
The Inoue-Balloon Catheter is a volume-controlled device and each catheter offers a number of inflation volumes, with corresponding balloon diameters. This allows the physician to carry out the PTMC procedure by incrementally increasing the size of the balloon from the minimum to the maximum inflation diameter. This approach is especially important in the elderly patient or in the patient with severe stenosis, but should be employed for all patients. The operator should begin valve dilatation with the smallest inflation volume, increasing the balloon diameter by only 1 or 2 mm on successive inflations as the situation warrants. This will result in the desired gradual opening of the stenosed mitral valve.
The following factors will assist the clinician in determining the number and inflation volume of subsequent dilatations:
- The appearance and degree of resultant mitral regurgitation;
- The increase in mitral valve area;
- The degree of separation of the mitral commissures; and
- The reduction of the pressure gradient across the mitral valve.
Contraindications, Warnings and Precautions
Contraindications for use of the Inoue-Balloon Catheter in Percutaneous Transvenous Mitral Commissurotomy (PTMC) include:
- Mitral valve area >1.5 cm²
- Mitral regurgitation >2+ (on a scale of 0-4)
- Asymptomatic patients
- Aortic regurgitation >2+ (on a scale of 0-4)
- Bacterial endocarditis
- Suspected formation of fresh (soft) blood thrombus in the left atrium<
- Suspected adhesion of blood thrombus on the interatrial septum or valve
- Severe subvalvular fibrosis documented by echocardiography in a patient who is an operative candidate or a good surgical risk.
- Severe mitral valve calcification in a patient who is an operative candidate or a good surgical risk.
- If mitral regurgitation occurs or increases significantly, the procedure must not be repeated using a larger inflation volume.
- Patients who have severe mitral valve calcification and/or severe subvalvular fibrosis should be considered candidates for the procedure only if they are non-operative candidates or poor surgical risks.
- Only physicians who have successfully completed Toray’s training programs and/or who have adequate experience with the device and the PTMC procedure should carry out this procedure.
- In facilities where the PTMC procedure is performed, in-house cardiac surgical backup is required, except in those cases where the patient is clearly too ill to undergo emergency surgery in the event of a serious complication related to the PTMC procedure.
- For balloon inflation, use only the syringe provided in the package; do not use other syringes with the Inoue Balloon Catheter. Conversely, do not use the Inoue Balloon Catheter syringe with other balloon catheters.
- After initial catheter introduction, do not disconnect or reconnect the metal hubs from each other or the "W" connector unless the guidewire is in place and fully protrudes from the catheter tip. Should this caution be disregarded, the catheter could bend at an acute angle resulting in damage to the device or difficulty in carrying out the procedure. Never use a kinked balloon.
- Using too large a balloon inflation volume could damage the valve or result in balloon malfunction, i.e., mesh tear. Once the balloon is inflated, the amount of time the valve opening is blocked must be minimal (5-7 sec).
- Do not exceed the maximum recommended inflation volume marked on the syringe provided in the package. Over-inflation of the balloon can result in tearing of the inner mesh fabric or other balloon malfunction. Do not use the balloon once it has experienced a mesh tear or any other malfunction.
- During manipulation of the stylet to direct the balloon, it is very important to hold the W-connector rather than the inner tube (proximal end of the catheter). If the inner tube is held, the lumen of the catheter can become twisted, thus occluding the lumen and blocking subsequent advancement or withdrawal of the guidewire or stylet. Do not twist the catheter lumen in this manner as it may adversely affect balloon performance.
- In the event that the balloon fails to deflate, do not use normal saline or any other fluid to inflate the balloon. Do not attempt to expand the balloon to the point of rupture, as several times the maximum inflation volume is required for rupture to occur.
- The design of the Inoue-Balloon Catheter does not lend itself to the use of power injection. For this reason, injection should be by hand only.
Possible complications associated with use of the Inoue-Balloon Catheter include, but are not limited to:
- Increase in valvular regurgitation.
- Failure of the catheter to traverse the stenotic valve orifice.
- Vasovagal reaction.
- Cardiac dysrhythmias such as atrial fibrillation, heart block, sinus bradycardia, and ventricular tachycardia or fibrillation.
- Vascular injury with or without the need for surgical intervention.
- Congestive heart failure or pulmonary edema.
- Failure or malfunction of the balloon or other components of the catheter kit.
- Injury to or perforation of the myocardial wall with or without cardiac tamponade.
- Damage to the mitral valve or ruptured chordae tendineae.
- Thrombus formation; embolization of thrombus, valve fragments, calcium, or air bubbles.
- Myocardial infarction.
- Transient ischemic attack; transient visual defect.
- Blood loss requiring fluid replacement or transfusion of blood products.
- Atrial septal defect, transient or persistent, with or without hemodynamic compromise.
- Allergy or anaphylactic reaction to dilute contrast medium or device components.
- Failure to traverse the vascular system with the balloon catheter.
- Decreased aortic pressure when the inflated balloon temporarily obstructs blood flow across the valve orifice.
- Loss of limb.
- Respiratory arrest.
- Renal failure.
In addition, it is possible that the procedure will produce insufficient hemodynamic improvement and the patient will have been exposed to the normal risks of cardiac catheterization. Furthermore, restenosis of the dilated valve may occur, with or without return of pre-treatment symptoms.
Disclaimer of warranty and Limitation of remedy
1) Toray will replace any defective the Inoue-Balloon Catheter and set contents (e.g., damaged product), free of charge. In the event of a product complaint, the user is requested to return the Inoue Balloon Catheter and packaging materials so that the cause of the complaint may be fully investigated.
2) Toray is not responsible for any damage caused due to improper handling, operation and storage, including use after the expiry date given on the product label.
3) Toray is not responsible for any damage to the Inoue-Balloon Catheter or its accessories caused by transportation, handling and storage at the health care facility, whether physical damage or human injury.
4) Do not use the Inoue-Balloon Catheter or its accessories with other manufacturers’ products. Toray is not responsible for any damage, whether physical damage or human injury, which may arise from the use of the Inoue-Balloon Catheter or its accessories with other manufacturers’ products.