a) Mitral Stenosis
Indications for Surgery
The nornlal mitral valve area is 4-5 cm2. Usually symptoms appear when the valve area has become less than 2.5 cm 2 . Sympton~s are present at rest when the valve area is less than 1.5 cm 2 . Mitral stenosis is classified as mild, moderate or severe based on: ( I ) pressure gradient across the valve on echo or cardiac catheterization, (2) calculated valve area.
The ideal operation for mitral stenosis used to be closed niitral valvolomy(CMV). To a large extent this has been replaced by balloon mitral vi~lvotorny(BMV). The indicatiolls and suitability of the valve as assessed by echocardiogrilphy arc thc same for CMV and BMV. The indications for surgery/invasive procedure have bccil detailed by American college of cardiology (ACC) and Ame~ican heart association (AHA) inlo evidencc Class 1, 2A, 2B and 3
Indications for Surgery
The nornlal mitral valve area is 4-5 cm2. Usually symptoms appear when the valve area has become less than 2.5 cm 2 . Sympton~s are present at rest when the valve area is less than 1.5 cm 2 . Mitral stenosis is classified as mild, moderate or severe based on: ( I ) pressure gradient across the valve on echo or cardiac catheterization, (2) calculated valve area.
The ideal operation for mitral stenosis used to be closed niitral valvolomy(CMV). To a large extent this has been replaced by balloon mitral vi~lvotorny(BMV). The indicatiolls and suitability of the valve as assessed by echocardiogrilphy arc thc same for CMV and BMV. The indications for surgery/invasive procedure have bccil detailed by American college of cardiology (ACC) and Ame~ican heart association (AHA) inlo evidencc Class 1, 2A, 2B and 3
Mlitral Valve Replacement
Patients who require surgery and are not candidates for BMV, CMV or OMV should have mitral valve replacement (MVR).
Types of Surgery for Mitral Stenosis
The surgical procedures for mitrd stenosis are:
1) Closed milral vdvotomy (CMV) also cdled closed mitrrtl commissurotomy(CMC) .
2) Open mitraI vdvotomy (OMV).
3) Mitral valve replacement (MVR).
Closed Mihal Vnlvotorny
This has been 1-eplaced by balloon rnitral valvotomy (BMV) in most centers. It is done in cases of either pure mitral stenosis or with .trivial regurgitation. The patient should be in sinus rhythm and echo should prove the suitability for a closed valvotomy just as for a balloon rnitral vaIvotamy. Heavy calcification in the commissures and edges of the cusps, moderate MR and the presence of a left atrial clot are contra indication for closed mitiral valvobmy.
Tccliazique: A median stemolomy is done; pe~i cardium opened and stay sutures taken. After lieparinisation ascending aorta is calanulated and then SVC and IVC cannulae inserted. If the Zcft atrium is small, hpes arc passed arouiid SVC and N C cannulae for Lola1 cardio pulmonary bypuss. Cardioplegia cannulae arc inserted into the ascending aorta and coronary sinus. The inter atrial grtnve is developed. Dissection to scpwdte RA from LA gives better exposure to the r n i m valve in case the kft atrium is very small. By dissecting under SVC and IVC more of left atrium will be available For atriotomy. Left atriulnl could also be approached through right abiotorny and incising the septum (Irans septa! approac11) or through h e roof of lefi atrium belwwn ascending aorta and superior vena cava (superior approach).
Aorta is clamped, %eft atrium opened and cacardioplegia is given. Ixft airium is widely opened and a Cooley alrial retractor or nhc self-retaining atrid reWdctor is applied. The valve h inspected for calcification and mobility. Stay sutures using 40' pmlene am &&en on the anterior and posterior cusp margins. By traction on the sutures the antemIateral and postern medial mrnrnissures are identified. Stab incisions are m& on the the comrniss~s close to the anl~ulus and from there extended to the c e m t d orifice of the valve. The incision must be along the true commissure. Tca@tion on the commissms using blunt hooks will help in identifjing the chordae and p p i l l i l ~ muscles. "Ihe fused chordae arr:xpar;rtebl by sRarp dissection after identifqring ihe ones going to either of the leaflets. It may require incision into the papillary muscles and at times fenesimion of tk fused chodae, "Ihu: essential principle is to get a mobile valve.
Decalcification of the leaflets will be required in some cases. The valve competence is kited by injecting saliw into the LV. LRCt atrial incision is closed and complete de-airing of the left side of the heart is done. Aortic clamp is removed and de-airing through the aortic root needle is continued till heart ejects well and good blood pressure is achieved. Trans oesophageal echo is done to make sure the valvotomy is adequate and mitral regurgitation is less than mild.
The assessnlent of MR should be when blood pressure is good.Open valvotomy is the procedure of choice when patient is in AF and left atrium has clots. The clots are removed; left atrium is washed and sucked thoroughly.Left atrial appendage is obliterated by tying it off from outside or by sutuiing from inside using prolene sutures. If the atrial fibiillation has been present for more than one year or left atrium is larger than 50mrns, it is better to combine a COX 111 (Maze) procedure to reduce the chances of post-operative atrial
fibrillation.
Mitral Valve Replacement
When mitral valve replacement for a calcified, stenotic valve is done, usually it is a classical procedure removing both leaflets, their chordae and p a t s of papillary muscles. However, if both leaflets and subvalvar apparatus could be preserved or at least the posterior leaflet, the results will be better. This is because the ellipsoidal shape of the ventricle and the geometry will be
maintained. This results in better LV function and the short and long-term results of MVR will be better.
Classic Procedure: The approach is the same as described earlier for open initral valvotomy. The excisioil starts with an anterior incision on the anterior leaflet at 12o'clock position, 2mm distal to the annulus. The incision is extended. The anterior leaflet with the chordae and the tip of the papillary muscle are removed.If the postei-ior leaflet is calcified, it is also excised along with chordae and tips of papillary muscles. Over zealous excision and sutuiing may cause venti.icular rupture or damage to circumflex coronary arteiy. Valve size is assessed according to the type of valve selected by the surgeon. The valve can be sutured by a continuous suture technique or interrupted pledgetted mattress sutures using 2 '0' braided polyester sutures. The pledgets are usually placed on the atrial aspect or rarely on the ventricular aspect.
Chol-dal Sparing Operation: For sparing both leaflets, an incision is made on the anterior leaflet close to the annulus and then extended centrally and the two segments a e folded towqds the posterior leaflet and pledgetted mattress sutures taken.decision is taken whether a prosthetic or bioprosthetic valve is to be inserted.Then the correct sized valve is chosen. In a stenotic valve with a small LV, a l o w profile valve is the best choice-St. Jude 01- Medtronic Hall. When the left ventricle is Iasge, a Starr-Edward valve can be inserted.Deairing should be thoroughly done. It is not advisable to lift the LV for deairing through the apex when a bioprosthetic valve has been inserted. Some patients with AF will require suturing of atrial appendage from inside and a COX LU
(MAZE) procedure as described in the case of open mitral valvotomy.Results of Mitral Valve Replacement: The risk of rnitral valve replacement is reported as 3-5 per cent. It also depends on multiple factors like age, functionaclass, concomitant coronary artery disease and other medical problems. In patients wfth ;iihuprasystemic PH and concomitant medical problems the risk may be as high as'10-20 per cent. Even if the patient is in class IV heart failure surgery should not be denied, as the outcome of conservative treatment is very poor. The inherent problems of prosthetic valves and anticoagulation related complications make a repair procedure more attractive if there is a chance to save one's own valve.
a) Mitral Regurgitation
Mitral regurgitation may be acute or chronic.
Acute Mitral Regurgitation
This may be caused by chordal iupture, infective endocarditis or acute myocardial infarction. In acute myocardial infarction, one of the papillary muscles may rupture leading to acute severe rnitral regurgitation. Infarction involving the base of the papillary muscle along with contiguous myocardium may lead to papillary muscle dysfunction resulting in milral regurgitation.There is usually sudden and severe onset of pulmonary venous hypertension and pulmonary oedema. There is no significant enlargement of left atrium and left ventricle. The murmur is not pan systolic and may have a crescendo-decrescendo character ending well before S2. X-ray will show a patteim of pulmollary oedema and ECG is diagnostic of infarction. Echocardiogram is diagnostic.
Chronic Mitral Regurgitation
Chronic mitral regurgitation may have different aetiological factors:
1) Rheumatic
2) Degenerative-myxomatous malformation
3) Infective elldocarditis
4) Mitral valve prolapse syndrome
5) Ischaemic--due to papillay muscle dysfunction or annular dilatation due to left ventricular enlargement
6) Sub valvar mitral aneulysm.
In severe chronic mitral regurgitation left ventricular after load is low because the LV ejection is partly into the left atrium. Due to this the LV ejection fraction may be spuriously high even when LV dysfunction has set in. So it is essential to assess the end systolic dimensions of left ventricle in recommending surgery.These days excellent 2D echo and doppler studies are available and these are used to assess (1) mitral regurgitant fraction, (2) LV ejection fraction, and (3) left ventricular dimension to decide on the necessity and timing of surgery in chronic mitral regurgitation.
Indications for Surgery
Acute Mitral Regurgitation
Acute rnitral regurgitation is an indication for early surgery. If patient is haemodynamically unstable, pre-operative intra aortic balloon pump insertion will help. In mild cases, vaso dilators and treatment of failure are instituted to get the patient to a chronic compensated phase for further assessment and surgery if required.
Chronic Mitral Regurgitation
In chronic mitral regurgitation, the asymptomatic phase is much longer than in mitral stenosis. Onset of symptoms may also mean the onset of left ventricular dysfunction. Asymptomatic patient with mild MR with no evidence of left ventricular. enlargement or dysfilnction or pulmonary hypertension can be medically followed up. In patients with moderate MR annual check up with
ec1~ocardiograpl~y should be done. Asyinptomatic patients with severe MR should have assessment every six months. Exercise stress testing may be needed in some cases.
1)Symptomatic patient: Symptomatic patient (class 11, 111 or IV) with severe MR and normal left ventricular function (EF > 0.6) and end systolic dimension of LV < 45 mrn require surgery. Attempt should be made to repair valve and if it is not possible valve replacement with preservation of all chordate and leaflets.
Asymptomatic patient: The current opinion is that in asymptomatic patients with left ventricular dysfunction and severe MR surgery should not be delayed. The echo cardiographic assessment of mild LV dysfunction is defined as EF 0.5 to 0.6 and left ventricular end systolic dimension 45 to 50mm. Similarly, moderate LV dysfunction is EF 0.3 to 0.5 and LV end systolic dimension is 50 to 55mms. Severe dysfunction is when EF is < 0.3 and end systolic LV dimension > 55 mms. When there is LV dysfunction all attempts should be made to repair the valve or if that is not possible, do a conservative valve replacement preserving both leaflets and chordae and
papillary muscles. A patient need not be rejected for surgical repair even if the ejection fraction is < 0.3 and left ventricular end systolic dimension is more than 55 rnm.
Asymptomatic patient with normal LV function and severe MR, should be followed up nledically. In an experienced center with.good succeSs in mitral valve repair, the current opinion is that rnitral valve 'repair should be advised. If such a patient is in atrial fibrillation, rnitral valve repair should be combined with surgery for AF'(C0X 111 -MAZE operation).In cases of ischaemic mitral regurgitation, a coronary a-teriogram is always done and coronary artery by pass is combined with mitral valve repair. All patients above 40'ye&s should have coronary ailgio before any valve surgery.
Mitral Valve Repair
Whenever possible, the valve has to be repaired rather than replaced. Pre-operative investigations and a TEE done on the operating table will help the surgeon in decision-making. Final decision is made on the table after studying and testing the valve.Alain Carpentier has perfected the technique of repair. According to him, the sectors (scallops) of the mitral leaflets are Al, A2 and A3 and on the posteiior leaflet PI, P2, P3 (lateral, central and medial sectors). From a reference point,which is usually PI, one can assess the regurgitation in each segment and how much prolapse or redundancy of each scallop is there and also decide whether the chordae are ruptured or just lengthened.
He has also classified the valve pathology as (1) type One - with normal leaflet motion where regurgitation is due to annular dilatation and failure of coaptation of the leaflets in the middle, (2) Type two - where excessive mobility and prolapse of the valve is there, and (3) Type three - with restricted valve mobility as in combined stenotic and regurgitant valve of rheumatic heart disease or calcified.valve due to other causes.
a) Mitral Regurgitation
Mitral regurgitation may be acute or chronic.
Acute Mitral Regurgitation
This may be caused by chordal iupture, infective endocarditis or acute myocardial infarction. In acute myocardial infarction, one of the papillary muscles may rupture leading to acute severe rnitral regurgitation. Infarction involving the base of the papillary muscle along with contiguous myocardium may lead to papillary muscle dysfunction resulting in milral regurgitation.There is usually sudden and severe onset of pulmonary venous hypertension and pulmonary oedema. There is no significant enlargement of left atrium and left ventricle. The murmur is not pan systolic and may have a crescendo-decrescendo character ending well before S2. X-ray will show a patteim of pulmollary oedema and ECG is diagnostic of infarction. Echocardiogram is diagnostic.
Chronic Mitral RegurgitationChronic mitral regurgitation may have different aetiological factors:
1) Rheumatic
2) Degenerative-myxomatous malformation
3) Infective elldocarditis
4) Mitral valve prolapse syndrome
5) Ischaemic--due to papillay muscle dysfunction or annular dilatation due to left ventricular enlargement
6) Sub valvar mitral aneulysm.
In severe chronic mitral regurgitation left ventricular after load is low because the LV ejection is partly into the left atrium. Due to this the LV ejection fraction may be spuriously high even when LV dysfunction has set in. So it is essential to assess the end systolic dimensions of left ventricle in recommending surgery.
Indications for Surgery
Acute Mitral Regurgitation
Acute rnitral regurgitation is an indication for early surgery. If patient is haemodynamically unstable, pre-operative intra aortic balloon pump insertion will help. In mild cases, vaso dilators and treatment of failure are instituted to get the patient to a chronic compensated phase for further assessment and surgery if required.
Chronic Mitral Regurgitation
In chronic mitral regurgitation, the asymptomatic phase is much longer than in mitral stenosis. Onset of symptoms may also mean the onset of left ventricular dysfunction. Asymptomatic patient with mild MR with no evidence of left ventricular. enlargement or dysfilnction or pulmonary hypertension can be medically followed up. In patients with moderate MR annual check up with ec1~ocardiograpl~y should be done. Asyinptomatic patients with severe MR should have assessment every six months. Exercise stress testing may be needed in some cases.
1)Symptomatic patient: Symptomatic patient (class 11, 111 or IV) with severe MR and normal left ventricular function (EF > 0.6) and end systolic dimension of LV < 45 mrn require surgery. Attempt should be made to repair valve and if it is not possible valve replacement with preservation of all chordate and leaflets.
Asymptomatic patient: The current opinion is that in asymptomatic patients with left ventricular dysfunction and severe MR surgery should not be delayed. The echo cardiographic assessment of mild LV dysfunction is defined as EF 0.5 to 0.6 and left ventricular end systolic dimension 45 to 50mm. Similarly, moderate LV dysfunction is EF 0.3 to 0.5 and LV end systolic dimension is 50 to 55mms. Severe dysfunction is when EF is < 0.3 and end systolic LV dimension > 55 mms. When there is LV dysfunction all attempts should be made to repair the valve or if that is not possible, do a conservative valve replacement preserving both leaflets and chordae and
papillary muscles. A patient need not be rejected for surgical repair even if the ejection fraction is < 0.3 and left ventricular end systolic dimension is more than 55 rnm.
Asymptomatic patient with normal LV function and severe MR, should be followed up nledically. In an experienced center with.good succeSs in mitral valve repair, the current opinion is that rnitral valve 'repair should be advised. If such a patient is in atrial fibrillation, rnitral valve repair should be combined with surgery for AF'(C0X 111 -MAZE operation).In cases of ischaemic mitral regurgitation, a coronary a-teriogram is always done and coronary artery by pass is combined with mitral valve repair. All patients
above 40'ye&s should have coronary ailgio before any valve surgery.
Mitral Valve Repair
Whenever possible, the valve has to be repaired rather than replaced. Pre-operative investigations and a TEE done on the operating table will help the surgeon in decision-making. Final decision is made on the table after studying and testing the valve.Alain Carpentier has perfected the technique of repair. According to him, the sectors (scallops) of the mitral leaflets are Al, A2 and A3 and on the posteiior leaflet PI, P2, P3 (lateral, central and medial sectors). From a reference point,which is usually PI, one can assess the regurgitation in each segment and how much prolapse or redundancy of each scallop is there and also decide whether the chordae are ruptured or just lengthened.
He has also classified the valve pathology as (1) type One - with normal leaflet motion where regurgitation is due to annular dilatation and failure of coaptation of the leaflets in the middle, (2) Type two - where excessive mobility and prolapse of the valve is there, and (3) Type three - with restricted valve mobility as in combined stenotic and regurgitant valve of rheumatic heart disease or calcified.valve due to other causes.
Technique of Operation
TEE,.probe is passed in all cases soon after anaesthesia. The initial steps and exposure of mitral valve are done as for open rnitral valvotomy. Using saline distension and by gentle pull with blunt hooks (crochet hooks) the valve mobility, prolapse, ruptured and e l o n ~ t e d chordae are studied for each sector of the leaflets.
Posterior Leaflet: In the posterior leaflet a quadrangular excision of the sector hvolved in the prolapse is done.. This may be up to 15-20 per cent of the leaflet.The remaining p a t of the posterior. leaflet is mobilized by resecting some adjacent s e c o n d q and tertiary chordae. The resulting gap in posterior leaflet is bridged by a hoiizontal pledgetted mattress suture (compression suture). The leaflet margins are then sutured with simple prolene sutures. If wider cluadrangular excision is needed, a sliding plasty is done detaching the posterior leaflet from the annulus to the desired length and suturing back to make allowance for the quadrangular excision. The leaflet margins are sutured with interrupted prolene sutures.
Carpentier: Edwards or similar annuloplasty ring is then sutured into place by interrupted sut~ires to support the repair and reduce the annulus to a measured amount. The ring may be rigid or flexible. The size is selected ~ ~ e a s u i i n the antero posteiior ,length of the splayed anterior leaflet.
Anterior Leaflet Procedure: Repair is more difficult and less successful.Previously, a triangular excision of the anterior leaflet used to be done for prolapse and rupture of chordae. The lengthened chordae can be shortened and ruptured ones replaced with Goretex chordae. The other technique done is tr<msfer of chordae from the posterior leaflet. This involves excision of small segment of anterior prolapsing leaflet and transferring a segment of the same size from posterior leaflet with its primary chordae intact. In the technique of chordal shortening, the papillary muscle is split and desired length of the lengthened chordae is embedded inside using prolene sutures. Ruptured chordae teildinae may be replaced with 5'0' Goretex (poly telra floura ethylene-PTFE) sutures.
Patients who require surgery and are not candidates for BMV, CMV or OMV should have mitral valve replacement (MVR).
Types of Surgery for Mitral Stenosis
The surgical procedures for mitrd stenosis are:
1) Closed milral vdvotomy (CMV) also cdled closed mitrrtl commissurotomy(CMC) .
2) Open mitraI vdvotomy (OMV).
3) Mitral valve replacement (MVR).
Closed Mihal Vnlvotorny
This has been 1-eplaced by balloon rnitral valvotomy (BMV) in most centers. It is done in cases of either pure mitral stenosis or with .trivial regurgitation. The patient should be in sinus rhythm and echo should prove the suitability for a closed valvotomy just as for a balloon rnitral vaIvotamy. Heavy calcification in the commissures and edges of the cusps, moderate MR and the presence of a left atrial clot are contra indication for closed mitiral valvobmy.
Tccliazique: A median stemolomy is done; pe~i cardium opened and stay sutures taken. After lieparinisation ascending aorta is calanulated and then SVC and IVC cannulae inserted. If the Zcft atrium is small, hpes arc passed arouiid SVC and N C cannulae for Lola1 cardio pulmonary bypuss. Cardioplegia cannulae arc inserted into the ascending aorta and coronary sinus. The inter atrial grtnve is developed. Dissection to scpwdte RA from LA gives better exposure to the r n i m valve in case the kft atrium is very small. By dissecting under SVC and IVC more of left atrium will be available For atriotomy. Left atriulnl could also be approached through right abiotorny and incising the septum (Irans septa! approac11) or through h e roof of lefi atrium belwwn ascending aorta and superior vena cava (superior approach).
Aorta is clamped, %eft atrium opened and cacardioplegia is given. Ixft airium is widely opened and a Cooley alrial retractor or nhc self-retaining atrid reWdctor is applied. The valve h inspected for calcification and mobility. Stay sutures using 40' pmlene am &&en on the anterior and posterior cusp margins. By traction on the sutures the antemIateral and postern medial mrnrnissures are identified. Stab incisions are m& on the the comrniss~s close to the anl~ulus and from there extended to the c e m t d orifice of the valve. The incision must be along the true commissure. Tca@tion on the commissms using blunt hooks will help in identifjing the chordae and p p i l l i l ~ muscles. "Ihe fused chordae arr:xpar;rtebl by sRarp dissection after identifqring ihe ones going to either of the leaflets. It may require incision into the papillary muscles and at times fenesimion of tk fused chodae, "Ihu: essential principle is to get a mobile valve.
Decalcification of the leaflets will be required in some cases. The valve competence is kited by injecting saliw into the LV. LRCt atrial incision is closed and complete de-airing of the left side of the heart is done. Aortic clamp is removed and de-airing through the aortic root needle is continued till heart ejects well and good blood pressure is achieved. Trans oesophageal echo is done to make sure the valvotomy is adequate and mitral regurgitation is less than mild.
The assessnlent of MR should be when blood pressure is good.Open valvotomy is the procedure of choice when patient is in AF and left atrium has clots. The clots are removed; left atrium is washed and sucked thoroughly.Left atrial appendage is obliterated by tying it off from outside or by sutuiing from inside using prolene sutures. If the atrial fibiillation has been present for more than one year or left atrium is larger than 50mrns, it is better to combine a COX 111 (Maze) procedure to reduce the chances of post-operative atrial
fibrillation.
Mitral Valve Replacement
When mitral valve replacement for a calcified, stenotic valve is done, usually it is a classical procedure removing both leaflets, their chordae and p a t s of papillary muscles. However, if both leaflets and subvalvar apparatus could be preserved or at least the posterior leaflet, the results will be better. This is because the ellipsoidal shape of the ventricle and the geometry will be
maintained. This results in better LV function and the short and long-term results of MVR will be better.
Classic Procedure: The approach is the same as described earlier for open initral valvotomy. The excisioil starts with an anterior incision on the anterior leaflet at 12o'clock position, 2mm distal to the annulus. The incision is extended. The anterior leaflet with the chordae and the tip of the papillary muscle are removed.If the postei-ior leaflet is calcified, it is also excised along with chordae and tips of papillary muscles. Over zealous excision and sutuiing may cause venti.icular rupture or damage to circumflex coronary arteiy. Valve size is assessed according to the type of valve selected by the surgeon. The valve can be sutured by a continuous suture technique or interrupted pledgetted mattress sutures using 2 '0' braided polyester sutures. The pledgets are usually placed on the atrial aspect or rarely on the ventricular aspect.
Chol-dal Sparing Operation: For sparing both leaflets, an incision is made on the anterior leaflet close to the annulus and then extended centrally and the two segments a e folded towqds the posterior leaflet and pledgetted mattress sutures taken.decision is taken whether a prosthetic or bioprosthetic valve is to be inserted.Then the correct sized valve is chosen. In a stenotic valve with a small LV, a l o w profile valve is the best choice-St. Jude 01- Medtronic Hall. When the left ventricle is Iasge, a Starr-Edward valve can be inserted.Deairing should be thoroughly done. It is not advisable to lift the LV for deairing through the apex when a bioprosthetic valve has been inserted. Some patients with AF will require suturing of atrial appendage from inside and a COX LU
(MAZE) procedure as described in the case of open mitral valvotomy.Results of Mitral Valve Replacement: The risk of rnitral valve replacement is reported as 3-5 per cent. It also depends on multiple factors like age, functionaclass, concomitant coronary artery disease and other medical problems. In patients wfth ;iihuprasystemic PH and concomitant medical problems the risk may be as high as'10-20 per cent. Even if the patient is in class IV heart failure surgery should not be denied, as the outcome of conservative treatment is very poor. The inherent problems of prosthetic valves and anticoagulation related complications make a repair procedure more attractive if there is a chance to save one's own valve.
a) Mitral Regurgitation
Mitral regurgitation may be acute or chronic.
Acute Mitral Regurgitation
This may be caused by chordal iupture, infective endocarditis or acute myocardial infarction. In acute myocardial infarction, one of the papillary muscles may rupture leading to acute severe rnitral regurgitation. Infarction involving the base of the papillary muscle along with contiguous myocardium may lead to papillary muscle dysfunction resulting in milral regurgitation.There is usually sudden and severe onset of pulmonary venous hypertension and pulmonary oedema. There is no significant enlargement of left atrium and left ventricle. The murmur is not pan systolic and may have a crescendo-decrescendo character ending well before S2. X-ray will show a patteim of pulmollary oedema and ECG is diagnostic of infarction. Echocardiogram is diagnostic.
Chronic Mitral Regurgitation
Chronic mitral regurgitation may have different aetiological factors:
1) Rheumatic
2) Degenerative-myxomatous malformation
3) Infective elldocarditis
4) Mitral valve prolapse syndrome
5) Ischaemic--due to papillay muscle dysfunction or annular dilatation due to left ventricular enlargement
6) Sub valvar mitral aneulysm.
In severe chronic mitral regurgitation left ventricular after load is low because the LV ejection is partly into the left atrium. Due to this the LV ejection fraction may be spuriously high even when LV dysfunction has set in. So it is essential to assess the end systolic dimensions of left ventricle in recommending surgery.These days excellent 2D echo and doppler studies are available and these are used to assess (1) mitral regurgitant fraction, (2) LV ejection fraction, and (3) left ventricular dimension to decide on the necessity and timing of surgery in chronic mitral regurgitation.
Indications for Surgery
Acute Mitral Regurgitation
Acute rnitral regurgitation is an indication for early surgery. If patient is haemodynamically unstable, pre-operative intra aortic balloon pump insertion will help. In mild cases, vaso dilators and treatment of failure are instituted to get the patient to a chronic compensated phase for further assessment and surgery if required.
Chronic Mitral Regurgitation
In chronic mitral regurgitation, the asymptomatic phase is much longer than in mitral stenosis. Onset of symptoms may also mean the onset of left ventricular dysfunction. Asymptomatic patient with mild MR with no evidence of left ventricular. enlargement or dysfilnction or pulmonary hypertension can be medically followed up. In patients with moderate MR annual check up with
ec1~ocardiograpl~y should be done. Asyinptomatic patients with severe MR should have assessment every six months. Exercise stress testing may be needed in some cases.
1)Symptomatic patient: Symptomatic patient (class 11, 111 or IV) with severe MR and normal left ventricular function (EF > 0.6) and end systolic dimension of LV < 45 mrn require surgery. Attempt should be made to repair valve and if it is not possible valve replacement with preservation of all chordate and leaflets.
Asymptomatic patient: The current opinion is that in asymptomatic patients with left ventricular dysfunction and severe MR surgery should not be delayed. The echo cardiographic assessment of mild LV dysfunction is defined as EF 0.5 to 0.6 and left ventricular end systolic dimension 45 to 50mm. Similarly, moderate LV dysfunction is EF 0.3 to 0.5 and LV end systolic dimension is 50 to 55mms. Severe dysfunction is when EF is < 0.3 and end systolic LV dimension > 55 mms. When there is LV dysfunction all attempts should be made to repair the valve or if that is not possible, do a conservative valve replacement preserving both leaflets and chordae and
papillary muscles. A patient need not be rejected for surgical repair even if the ejection fraction is < 0.3 and left ventricular end systolic dimension is more than 55 rnm.
Asymptomatic patient with normal LV function and severe MR, should be followed up nledically. In an experienced center with.good succeSs in mitral valve repair, the current opinion is that rnitral valve 'repair should be advised. If such a patient is in atrial fibrillation, rnitral valve repair should be combined with surgery for AF'(C0X 111 -MAZE operation).In cases of ischaemic mitral regurgitation, a coronary a-teriogram is always done and coronary artery by pass is combined with mitral valve repair. All patients above 40'ye&s should have coronary ailgio before any valve surgery.
Mitral Valve Repair
Whenever possible, the valve has to be repaired rather than replaced. Pre-operative investigations and a TEE done on the operating table will help the surgeon in decision-making. Final decision is made on the table after studying and testing the valve.Alain Carpentier has perfected the technique of repair. According to him, the sectors (scallops) of the mitral leaflets are Al, A2 and A3 and on the posteiior leaflet PI, P2, P3 (lateral, central and medial sectors). From a reference point,which is usually PI, one can assess the regurgitation in each segment and how much prolapse or redundancy of each scallop is there and also decide whether the chordae are ruptured or just lengthened.
He has also classified the valve pathology as (1) type One - with normal leaflet motion where regurgitation is due to annular dilatation and failure of coaptation of the leaflets in the middle, (2) Type two - where excessive mobility and prolapse of the valve is there, and (3) Type three - with restricted valve mobility as in combined stenotic and regurgitant valve of rheumatic heart disease or calcified.valve due to other causes.
a) Mitral Regurgitation
Mitral regurgitation may be acute or chronic.
Acute Mitral Regurgitation
This may be caused by chordal iupture, infective endocarditis or acute myocardial infarction. In acute myocardial infarction, one of the papillary muscles may rupture leading to acute severe rnitral regurgitation. Infarction involving the base of the papillary muscle along with contiguous myocardium may lead to papillary muscle dysfunction resulting in milral regurgitation.There is usually sudden and severe onset of pulmonary venous hypertension and pulmonary oedema. There is no significant enlargement of left atrium and left ventricle. The murmur is not pan systolic and may have a crescendo-decrescendo character ending well before S2. X-ray will show a patteim of pulmollary oedema and ECG is diagnostic of infarction. Echocardiogram is diagnostic.
Chronic Mitral RegurgitationChronic mitral regurgitation may have different aetiological factors:
1) Rheumatic
2) Degenerative-myxomatous malformation
3) Infective elldocarditis
4) Mitral valve prolapse syndrome
5) Ischaemic--due to papillay muscle dysfunction or annular dilatation due to left ventricular enlargement
6) Sub valvar mitral aneulysm.
In severe chronic mitral regurgitation left ventricular after load is low because the LV ejection is partly into the left atrium. Due to this the LV ejection fraction may be spuriously high even when LV dysfunction has set in. So it is essential to assess the end systolic dimensions of left ventricle in recommending surgery.
Indications for Surgery
Acute Mitral Regurgitation
Acute rnitral regurgitation is an indication for early surgery. If patient is haemodynamically unstable, pre-operative intra aortic balloon pump insertion will help. In mild cases, vaso dilators and treatment of failure are instituted to get the patient to a chronic compensated phase for further assessment and surgery if required.
Chronic Mitral Regurgitation
In chronic mitral regurgitation, the asymptomatic phase is much longer than in mitral stenosis. Onset of symptoms may also mean the onset of left ventricular dysfunction. Asymptomatic patient with mild MR with no evidence of left ventricular. enlargement or dysfilnction or pulmonary hypertension can be medically followed up. In patients with moderate MR annual check up with ec1~ocardiograpl~y should be done. Asyinptomatic patients with severe MR should have assessment every six months. Exercise stress testing may be needed in some cases.
1)Symptomatic patient: Symptomatic patient (class 11, 111 or IV) with severe MR and normal left ventricular function (EF > 0.6) and end systolic dimension of LV < 45 mrn require surgery. Attempt should be made to repair valve and if it is not possible valve replacement with preservation of all chordate and leaflets.
Asymptomatic patient: The current opinion is that in asymptomatic patients with left ventricular dysfunction and severe MR surgery should not be delayed. The echo cardiographic assessment of mild LV dysfunction is defined as EF 0.5 to 0.6 and left ventricular end systolic dimension 45 to 50mm. Similarly, moderate LV dysfunction is EF 0.3 to 0.5 and LV end systolic dimension is 50 to 55mms. Severe dysfunction is when EF is < 0.3 and end systolic LV dimension > 55 mms. When there is LV dysfunction all attempts should be made to repair the valve or if that is not possible, do a conservative valve replacement preserving both leaflets and chordae and
papillary muscles. A patient need not be rejected for surgical repair even if the ejection fraction is < 0.3 and left ventricular end systolic dimension is more than 55 rnm.
Asymptomatic patient with normal LV function and severe MR, should be followed up nledically. In an experienced center with.good succeSs in mitral valve repair, the current opinion is that rnitral valve 'repair should be advised. If such a patient is in atrial fibrillation, rnitral valve repair should be combined with surgery for AF'(C0X 111 -MAZE operation).In cases of ischaemic mitral regurgitation, a coronary a-teriogram is always done and coronary artery by pass is combined with mitral valve repair. All patients
above 40'ye&s should have coronary ailgio before any valve surgery.
Mitral Valve Repair
Whenever possible, the valve has to be repaired rather than replaced. Pre-operative investigations and a TEE done on the operating table will help the surgeon in decision-making. Final decision is made on the table after studying and testing the valve.Alain Carpentier has perfected the technique of repair. According to him, the sectors (scallops) of the mitral leaflets are Al, A2 and A3 and on the posteiior leaflet PI, P2, P3 (lateral, central and medial sectors). From a reference point,which is usually PI, one can assess the regurgitation in each segment and how much prolapse or redundancy of each scallop is there and also decide whether the chordae are ruptured or just lengthened.
He has also classified the valve pathology as (1) type One - with normal leaflet motion where regurgitation is due to annular dilatation and failure of coaptation of the leaflets in the middle, (2) Type two - where excessive mobility and prolapse of the valve is there, and (3) Type three - with restricted valve mobility as in combined stenotic and regurgitant valve of rheumatic heart disease or calcified.valve due to other causes.
Technique of Operation
TEE,.probe is passed in all cases soon after anaesthesia. The initial steps and exposure of mitral valve are done as for open rnitral valvotomy. Using saline distension and by gentle pull with blunt hooks (crochet hooks) the valve mobility, prolapse, ruptured and e l o n ~ t e d chordae are studied for each sector of the leaflets.
Posterior Leaflet: In the posterior leaflet a quadrangular excision of the sector hvolved in the prolapse is done.. This may be up to 15-20 per cent of the leaflet.The remaining p a t of the posterior. leaflet is mobilized by resecting some adjacent s e c o n d q and tertiary chordae. The resulting gap in posterior leaflet is bridged by a hoiizontal pledgetted mattress suture (compression suture). The leaflet margins are then sutured with simple prolene sutures. If wider cluadrangular excision is needed, a sliding plasty is done detaching the posterior leaflet from the annulus to the desired length and suturing back to make allowance for the quadrangular excision. The leaflet margins are sutured with interrupted prolene sutures.
Carpentier: Edwards or similar annuloplasty ring is then sutured into place by interrupted sut~ires to support the repair and reduce the annulus to a measured amount. The ring may be rigid or flexible. The size is selected ~ ~ e a s u i i n the antero posteiior ,length of the splayed anterior leaflet.
Anterior Leaflet Procedure: Repair is more difficult and less successful.Previously, a triangular excision of the anterior leaflet used to be done for prolapse and rupture of chordae. The lengthened chordae can be shortened and ruptured ones replaced with Goretex chordae. The other technique done is tr<msfer of chordae from the posterior leaflet. This involves excision of small segment of anterior prolapsing leaflet and transferring a segment of the same size from posterior leaflet with its primary chordae intact. In the technique of chordal shortening, the papillary muscle is split and desired length of the lengthened chordae is embedded inside using prolene sutures. Ruptured chordae teildinae may be replaced with 5'0' Goretex (poly telra floura ethylene-PTFE) sutures.
Alfieri Repair: This is advised for ischaenlic initral regurgitation. In the area of prolapse, the anleiior and posterior leaflet edges are approximated with one or two mattress sutures (edge to edge repair). If done for prolapse of the middle leaflet the mattress sutures effectively make a double orifice mitral valve, which functions adequately for a period of time.
In babies and children, annuloplasty ring is avoided, as they need further growth of the annulus.Valves are tested by distending with saline. Previous methods of dynamic testing with the heart beating and left atrium open are given up. P eference is given to TEE Lesling 011 conling off bypass with good systemic pressure. With cannulae not removed, one call go again and do further repair or replacement.
c)Mixed Mitral Stenosis and Regurgitation
The most coinmon cause for a combined lesion is rheumatic, Very rarely, it could be of congenital origin. Regurgitation in a stenotic valve could be iatrogenic -either after a balloon valvotoiny or closed initral valvotomy. In a mixed lesion,either the stenosis or the regurgitation is the more dominant lesion.
Haemodynamics and natural history depends on the dominant lesion.
Indications for surgery also depend on the donlinant lesion. Surgical treatment is often mitral valve replacement as satisfactory repair is difficult to achieve and long-term results unpredictable.
Indications for surgery also depend on the donlinant lesion. Surgical treatment is often mitral valve replacement as satisfactory repair is difficult to achieve and long-term results unpredictable.
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