Over the last two decades, significant strides have been made in the field of Balloon Valvuloplasties both in terms of technique as well as equipment.
Percutaneous Balloon Mitral Valvuloplasty
Percutaneous balloon mitral valvuloplasty has emerged as the treatment of choice in patients with Rheumatic mitral stenosis which is rampant in developing countries.
Mechanism of PBMV
Mitral valvuloplasty works by the principle of “commisurotomy” — by increasing the mitral orifice area by splitting the fused commisures. The expanding balloon splits fused commisures akin to surgical commisurotomy.
Patient Selection
The patients who are suitable for balloon mitral valvuloplasty are:
1) Patients who are symptomatic with a mitral orifice area as determined by echocardiography and haemodynamics studies to be <1.5cm 2
2) Patients with pulmonary hypertension, severe mitral stenosis and variable LV function with anatomically suitable valve
3) Patients with mitral Restenosis after previous surgical commisurotomy in anatomically suitable valves
4) Younger the patient, better the results as older patients have fibrotic valves
5) Suitable procedure for pregnant women with mitral stenosis
6)Life saving procedure in patients of mitral stenosis in pulmonary edema or cardiogenic shock
Contraindications to Mitral Valvuloplasty
1) Left atrial thrombus
2) Moderate or greater (2+) mitral regurgitation
3) Concomitant severe coronary artery disease
Anatomic Factors in Patient Selection for Mitral Valvuloplasty The ideal patient is young, has pliable non calcified mitral leaflets, and mild subvalvular disease.TEE may be necessary to exclude LA thrombus and significant mitral regurgitation pre- procedure. Massive valvular calcification and bicommisural calcification are obviously contraindications for the procedure
The echocardiographic scoring system by Wilkins et al is very helpful to decide an anatomically suitable valve for Mitral Valvuloplasty. The maximum score is 16. A score of < 8 generally gives excellent results.
Echocardiographic Scoring System (Wilkins’ et al.)
Technique of Balloon Mitral Valvuloplasty
There are two basic techniques:
1) Double balloon technique
2) Inoue technique
For the purpose of convenience, the Inoue technique will be described.
Inoue Technique
The procedure is performed by cannulation of the right femoral vein and the procedure is similar upto transseptal puncture which allows access into the left atrium. Following this the transseptal puncture, a Mullins type dilator and sheath is placed in the left atrium. The patient is anticoagulated with heparin after entry into LA. A coiled guidewire is passes through the Mullinssheath into the left atrium and the mullins sheath is removed. A long dilator is used to dilate the passage into the femoral vein and inter atrial septum. The dilator is removed and the Inoue balloon is threaded over the guidewire and maneuvered into the left atrium. A “J” stylet is inserted into the balloon and manipulated so as to position the Inoue balloon across the mitral valve. The balloon is then inflated – distal portion first, pulled back gently upto the narrowest position of the valve. Then the proximal portion is inflated. Finally the waist of the balloon is inflated to effectively cause commissural splitting.
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| Inoue Technique |
Both the immediate and long term results of balloon valvuloplasty are excellent. Complications are few and the most dreadful are hemopericardium, systemic embolization or production of severe mitral regurgitation.
Balloon Pulmonary Valvuloplasty
Pulmonary stenosis is a relatively common congenital heart defect. Usually these children with mild to moderate pulmonary stenosis survive into childhood. Since bicuspid pulmonary stenosis is infrequent (< 20 per cent) and heavy calcification uncommon, pulmonary stenosis is well suited for balloon pulmonary valvuloplasty.
Classification of Severity of Pulmonary Stenosis
Severity to PS Transvalvular Gradient
Mild PS < 50 mmHg
Moderate PS 50 - 100 mmHg
25Severe PS> 100 mmHg
Technique
Right heart study is done to measure the transvalvular gradient and exclude supravalvular and subvalvular components. A 5F sheath is placed in the right femoral artery for pressure monitoring and an 8F sheath is placed in the right femoral vein for the BPV procedure. An RV angiogram is performed in AP and lateral views to assess location of PV and for sizing of the pulmonary annulus. It is often necessary to oversize the balloon 25 to 30 per cent larger than the valve annulus diameter. In general balloon pulmonary valvuloplasty procedure is indicated if the resting peak systolic pressure exceeds 40mmHg. Lateral projection is best suited for the procedure. An end hole catheter is positioned into the left pulmonary artery. An exchange length guide wire is anchored in distal LPA. A double balloon technique is recommended if pulmonary annulus exceeds 18-19mm, or if the single balloon catheter required for the procedure is too large for introduction into the patient’s femoral vein. With double balloon technique, the balloon diameter sum is 60 per cent more than the annulus diameter. The balloon valvuloplasty catheter is advanced across the valve and positioned with the valve in the midportion of the balloon. The valvuloplasty balloon or balloons are then inflated with, a mixture of saline and contrast, by hand, until the waist disappears. The procedure can be repeated if necessary for adequate pulmonary valve dilatation. The valvuloplasty catheter is removed and a wedge catheter is used to record the RV outflow tract gradient and cardiac output to document efficacy of the procedure followed by an RV angiogram. The acute and long-term results of this procedure have been very satisfying.
Aortic Valvuloplasty
Valvar aortic stenosis accounts for 4-6 per cent of CHD. LV Outflow Tract obstruction eventually leads to LV dysfunction and congestive heart failure.Congenital AS, unlike PS, progresses over time. Intervention is indicated if the LVOT obstruction is severe (catheter gradient > 65mmHg), or associated symptoms like LV dysfunction, heart failure, angina, syncope or presyncope.
Indications for Balloon Aortic Valvuloplasty
1) Peak systolic pressure gradient at rest of > 65mmHg.
2) Peak systolic pressure gradient at rest of 50-64mmHg with symptoms
3) Low cardiac output regardless of the gradient.
Technique
BAV is usually performed by the retrograde transarterial approach. Often another catheter is placed in the LV through transseptal approach to provide continuous LV pressure monitoring throughout the procedure. The AS gradient is measured before angiography from simultaneous ventricular and aortic pressure recordings. After transseptal puncture, heparin is administered to keep the Activated Clotting Time 250-300sec. The aortic valve is crossed in a retrograde manner and a pigtail catheter is positioned in LV apex. If it cannot be crossed retrogradely, it can be crossed antegradely using a transseptal catheter. An exchange length guidewire is passed from the femoral arterial sheath and is used to guide the balloon dilatation catheter across the aortic valve in a retrograde direction.
Biplane LV angiogram is performed in 70 0 LAO, 20 0 cranial angulation and frontal or RAO projections. The aortic annulus is best measured in LAO view or in echo. Valvuloplasty is performed by single or double balloon technique. Exchange length wire is passed across the aortic valve and anchored in LV apex. A balloon whose diameter is same or 1mm less than the aortic annulus is chosen. For double balloons, the sum of diameter of the balloons should not exceed 1.2 to 1.3 times the aortic annulus. The balloon/balloons are inflated across the aortic valve until the waist disappears. Aortic root angiogram is performed post procedure to assess aortic regurgitation.
Balloon Pulmonary Valvuloplasty
Pulmonary stenosis is a relatively common congenital heart defect. Usually these children with mild to moderate pulmonary stenosis survive into childhood. Since bicuspid pulmonary stenosis is infrequent (< 20 per cent) and heavy calcification uncommon, pulmonary stenosis is well suited for balloon pulmonary valvuloplasty.
Classification of Severity of Pulmonary Stenosis
Severity to PS Transvalvular Gradient
Mild PS < 50 mmHg
Moderate PS 50 - 100 mmHg
25Severe PS> 100 mmHg
Technique
Right heart study is done to measure the transvalvular gradient and exclude supravalvular and subvalvular components. A 5F sheath is placed in the right femoral artery for pressure monitoring and an 8F sheath is placed in the right femoral vein for the BPV procedure. An RV angiogram is performed in AP and lateral views to assess location of PV and for sizing of the pulmonary annulus. It is often necessary to oversize the balloon 25 to 30 per cent larger than the valve annulus diameter. In general balloon pulmonary valvuloplasty procedure is indicated if the resting peak systolic pressure exceeds 40mmHg. Lateral projection is best suited for the procedure. An end hole catheter is positioned into the left pulmonary artery. An exchange length guide wire is anchored in distal LPA. A double balloon technique is recommended if pulmonary annulus exceeds 18-19mm, or if the single balloon catheter required for the procedure is too large for introduction into the patient’s femoral vein. With double balloon technique, the balloon diameter sum is 60 per cent more than the annulus diameter. The balloon valvuloplasty catheter is advanced across the valve and positioned with the valve in the midportion of the balloon. The valvuloplasty balloon or balloons are then inflated with, a mixture of saline and contrast, by hand, until the waist disappears. The procedure can be repeated if necessary for adequate pulmonary valve dilatation. The valvuloplasty catheter is removed and a wedge catheter is used to record the RV outflow tract gradient and cardiac output to document efficacy of the procedure followed by an RV angiogram. The acute and long-term results of this procedure have been very satisfying.
Aortic Valvuloplasty
Valvar aortic stenosis accounts for 4-6 per cent of CHD. LV Outflow Tract obstruction eventually leads to LV dysfunction and congestive heart failure.Congenital AS, unlike PS, progresses over time. Intervention is indicated if the LVOT obstruction is severe (catheter gradient > 65mmHg), or associated symptoms like LV dysfunction, heart failure, angina, syncope or presyncope.
Indications for Balloon Aortic Valvuloplasty
1) Peak systolic pressure gradient at rest of > 65mmHg.
2) Peak systolic pressure gradient at rest of 50-64mmHg with symptoms
3) Low cardiac output regardless of the gradient.
Technique
BAV is usually performed by the retrograde transarterial approach. Often another catheter is placed in the LV through transseptal approach to provide continuous LV pressure monitoring throughout the procedure. The AS gradient is measured before angiography from simultaneous ventricular and aortic pressure recordings. After transseptal puncture, heparin is administered to keep the Activated Clotting Time 250-300sec. The aortic valve is crossed in a retrograde manner and a pigtail catheter is positioned in LV apex. If it cannot be crossed retrogradely, it can be crossed antegradely using a transseptal catheter. An exchange length guidewire is passed from the femoral arterial sheath and is used to guide the balloon dilatation catheter across the aortic valve in a retrograde direction.
Biplane LV angiogram is performed in 70 0 LAO, 20 0 cranial angulation and frontal or RAO projections. The aortic annulus is best measured in LAO view or in echo. Valvuloplasty is performed by single or double balloon technique. Exchange length wire is passed across the aortic valve and anchored in LV apex. A balloon whose diameter is same or 1mm less than the aortic annulus is chosen. For double balloons, the sum of diameter of the balloons should not exceed 1.2 to 1.3 times the aortic annulus. The balloon/balloons are inflated across the aortic valve until the waist disappears. Aortic root angiogram is performed post procedure to assess aortic regurgitation.
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