STS Benchmark - Valve Flashcards
Risk factors for TR recurrence after repair.
Recurrent regurgitation after tricuspid valve repair is rather common. In a series of 790 patients who had tricuspid valve repair for functional regurgitation at the Cleveland Clinic from 1990 to 1999, the incidence of residual 3+ or 4+ regurgitation at one month postoperatively was 15%.
At 5 years, this remained stable when a standard annuloplasty band was implanted (17% to 18%), but increased to 33% for DeVega suture annuloplasty and 37% when a bovine pericardial band was used. Risk factors for worsening regurgitation included higher preoperative regurgitation grade, poor left ventricular function, transvenous ventricular pacing leads, and either suture or bovine pericardial annuloplasty technique.
Interestingly, right ventricular systolic pressure and tricuspid ring size were NOT significant risk factors for recurrent regurgitation.
You are considering aortic valve replacement for a 41-year-old man with symptomatic aortic valve disease. Which of the following statements is true?
The risk of bleeding complications due to warfarin therapy following mechanical valve replacement is <2% per year.
The risk of reoperative aortic valve surgery prohibits the use of a bioprosthetic valve in patients under age 45.
The Ross Procedure is the procedure of choice for patients 25-45 years old.
A cryopreserved allograft has the greatest freedom from structural deterioration and reoperation at 10 years compared to other valve choices.
The risk of bleeding complications due to warfarin therapy following mechanical valve replacement is <2% per year.
While the Ross procedure is being utilized more frequently in the young adult population there are no data documenting its superiority and freedom from reintervention to the point that it is considered the procedure of choice. However, because of the potential for growth of the pulmonary autograft, it could be considered the optimal aortic replacement valve in the pediatric population.
Although many studies have documented previous aortic valve surgery to be an independent risk factor for operative mortality during aortic valve surgery, this risk is not prohibitive. A recent report by Cosgrove et al documented that previous aortic valve surgery is not a significant risk factor for mortality during repeat aortic valve surgery.
Patients receiving a mechanical aortic prosthesis need life-long anticoagulation therapy to optimally avoid valve thrombosis and thromboembolic complications. While these patients are at risk for hemorrhagic complications, close monitoring of the INR to keep this value between 2.0 and 3.0 should keep the risk for hemorrhagic complications at less than 2.0% per year. Cryopreserved allograft valves and heterograft bioprosthetic valves have roughly a 90-95% freedom from structural valve deterioration at 10 years. Modern mechanical valves are essentially free from structural failure. Non-structural dysfunction can occur with mechanical valves, as with other valve choices, and can lead to the need for reoperation. Because no valve replacement option is perfect, each patient should be informed of the benefits and limitations of each option and should be allowed the freedom to choose which choice is best for them.
One week following surgery for mitral regurgitation, a radionuclide study reveals an increase in resting ejection fraction and no change in end-diastolic volume of the left ventricle compared to a preoperative study.
What is the likely explanation?
Perivalvular leak after mitral valve replacement.
Resting ejection fraction (EF) often decreases after mitral valve surgery because of mechanical factors or problems with myocardial protection.
Mechanical factors include division of the chordae tendineae, a rigid ring in the mitral annulus, and increased afterload due to elimination of the low resistance leak to the left atrium. Some evidence suggests that resting EF may improve after valve repair, but this has only been reported with a decrease in end-diastolic volume of the left ventricle (LVEDV).
Resting EF and LVEDV decrease with flexible rings. Elastance, a load-independent measure of contractility, is a better parameter than EF for studying the effects of mitral surgery on function. Decreased elastance should decrease resting EF.
Surgical preservation of chordae tendineae might minimize deterioration of EF but this has not been reported to increase resting EF. A perivalvular leak is functionally equivalent to mitral regurgitation and is similar to the preoperative state. This is the most likely cause of the functional changes described.
A frail 70-year-old woman is currently undergoing mitral valve replacement with a bioprosthesis. As cardiopulmonary bypass is discontinued bleeding is noted to originate posteriorly from the vicinity of the left atrioventricular junction. The surgeon should resume bypass, arrest the heart and…
perform internal repair and implant a non-oversized valve
Elderly patients are more prone to develop posterior ventricular disruption/ AV groove disruption during or following mitral valve replacement (MVR), and this may occur at the mid ventricular level or at the atrioventricular junction. Bleeding from this complication may be massive. External inspection of the heart allows the surgeon to see only the point of egress of blood, and the act of inspection for posterior bleeding following MVR carries danger. Repair of ventricular disruption is difficult, and the mortality of this complication is very high. External repairs jeopardize the circumflex coronary artery, its marginal branches and the coronary sinus. Again, exposure of the posterior atrioventricular groove following MVR is difficult and dangerous, and the precise site of bleeding usually cannot be identified for accurate suture repair.
Most authors recommend internal repair utilizing a patch of pericardium or synthetic material, followed by careful implantation of a low profile mechanical prosthesis. Internal inspection of the heart and removal of the valve prosthesis allow a more thorough inspection and evaluation of the injury. If injury or compromise of the circumflex territory is suspected as part of the complication, then a distal coronary artery anastomosis should be performed following removal of the initial prosthesis and prior to replacing the valve again.
For patients with bAV, are calcific deposits the rule for most of these patients by age 30?
The majority of patients with congenitally bicuspid aortic valves do not have significant aortic valve obstruction in the early years of life, but abnormal valvular calcification is present in nearly all these patients by 30 years of age. In patients who require aortic valvotomy in infancy or childhood, a successful procedure does not eliminate progressive degenerative changes. Calcification often mandates repeat valvotomy or valve replacement during adult life.
Most common etiology of AS in patients over 65?
Fibrocalcific aortic stenosis results from occult degenerative changes characterized by collagen disruption and calcific deposits. The calcification characteristically begins in the sinuses of Valsalva and progresses to involve fusion of the commissures. Extensive calcification of the leaflets with extension to the adjacent aortic wall and onto the anterior leaflet of the mitral valve are late findings. This form of aortic valve disease is the most common etiology of aortic stenosis in patients over 65 years of age.
How common is bAV in the general population?sc
One of the most common underlying causes of aortic stenosis is a congenitally bicuspid valve. This occurs in approximately 1% of the general population.
Describe the pathophysiology of rheumatic fever in its progression to AS?
Rheumatic fever may be associated with a valvulitis that can progress over time to aortic stenosis. The inflammatory process results in lymphocytic infiltration, edema, and neovascularization of the valve leaflets. Fusion of the valve leaflets along the commissures and adjacent cusps is frequent, as is leaflet calcification. The result is an immobile ring of rigid valvular tissue which appears as a fixed triangular central orifice.
Compared to bioprosthetic aortic valve replacement, the Ross Operation (pulmonary valve and root autotransplant to the aortic root and homograft pulmonary root replacement) is characterized by?
reduced incidence of endocarditis.
increased operative time.
anteroseptal myocardial infarction.
increased blood loss.
Autotransplantation of the pulmonary valve or root as a composite to the aortic position was initially performed to obviate the problem of early calcification and degeneration of tissue valves in young patients. Ross began a series of such autotransplants in 1967. This experience has confirmed the durability of the pulmonary valve in the aortic position, and the specific problem of early calcification has been eliminated. The primary technical concerns of the procedure relate to achieving meticulous hemostasis and avoiding injury to the left anterior descending coronary artery and its first septal perforating branch during excision of the pulmonary root. Right heart failure has not been reported.
A 48-year-old, 75 kg man had severe mitral valve regurgitation and a non-diseased left-dominant coronary system. Mitral valve repair was performed with a large quadrangular resection of the posterior leaflet and ring annuloplasty. After weaning from bypass the patient has persistent ST-segment elevation in leads II, III, and AVF, and posterior wall hypokinesis is noted on echocardiography. There is no residual mitral insufficiency and no systolic anterior motion. BP is 85/60 mmHg, PA pressure is 55/32, and cardiac output is 2.5 L/min.
Differential?
The best treatment is?
The potential causes of ST-segment elevations in leads II, III, and AVF after mitral valve repair or replacement include poor perfusion secondary to transient air in the inferior ventricular (usually right coronary) circulation, a current of injury secondary to ischemia from inadequate myocardial protection, coronary spasm and myocardial infarction. ST-segment changes secondary to coronary air, from a current of injury or from coronary spasm should be transient. Such ECG changes should normalize if adequate perfusion pressure and hemodynamics are maintained, although nitrates and calcium channel blockers might be helpful if coronary spasm is suspected. If the ST-segment elevations are persistent and associated with systemic hypotension, pulmonary hypertension and low cardiac output as described, then myocardial infarction is the most likely diagnosis. Following a large quadrangular resection of the posterior leaflet, kinking or injury to the circumflex coronary artery is the most likely explanation. Similarly, the circumflex coronary artery may be injured by sutures during mitral valve replacement. In either case the best treatment is to perform coronary bypass to the distal circumflex marginal artery. In an unstable patient, this should be done immediately, before transmural infarction and permanent damage occur. To terminate the operation and proceed to coronary angiography is unwise. Placing an intra-aortic balloon pump provides hemodynamic support, but it does not correct the underlying problem and the delay risks irreversible transmural infarction. Since the mitral valve is competent and since the artery may have been irreversibly damaged, there is no indication to take down the repair and replace the valve.
A 43-year-old woman had mitral valve prolapse and moderate mitral regurgitation secondary to a flail middle scallop of the posterior leaflet. Her left ventricular ejection fraction was 60%. Mitral valve repair was done with a partial posterior leaflet quadrangular resection, posterior annular plication, leaflet reapproximation, and a #28 ring annuloplasty. Her post-bypass transesophageal echocardiogram demonstrates an excellent repair with complete elimination of mitral regurgitation and no gradient. Twelve hours after surgery the patient has had a moderate amount of bleeding through the thoracostomy tubes. Blood pressure is now 112/67, RA is 10 and PA is 36/14. Her cardiac index has decreased to 1.6 and PA oxygen saturation is now 45%. Hemoglobin is 10gm/dl. The epinephrine infusion is increased from 2 to 4 mcg/min and her heart is increased from 70 to 90 with atrial pacing.
Echo shows a redundant posterior leaflet.
What is happening? What do you do?
Systolic anterior motion of the mitral valve leading to aortic outflow tract obstruction is a well recognized complication of mitral valve repair.
It is caused by a repair that leaves the coaptation point of the anterior and posterior leaflet too anterior toward the aortic valve and sometimes by too small of a annuloplasty ring. It is seen in patients with a large, redundant posterior leaflet. In this case, this was was not recognized.
An appropriate initial action would have been to initially perform a sliding plasty of the posterior leaflet and a larger annuloplasty ring. Given that this was not done, reasonable options (after failure of medical management including volume loading, removal of inotropes, beta-blockade, etc.) include return to the operating room to redo the repair with a larger ring and a sliding plasty or mitral valve replacement with a low-profile mechanical valve.
How do you manage a small paravalvular leak after a bio-AVR requiring extensive debridement of a calcified aortic valve?
Leave this alone. Often they resolve with protamine. Often they are clinically insignificant in the long-term. Moderate and severe paravalvular leaks require immediate re-repair.
Periprosthetic (paravalvular) leaks may be associated with significant morbidity depending on the degree of regurgitation and hemolysis. Large chronic jets can produce symptoms of valvular regurgitation while moderate-sized jets can cause hemolysis due to turbulence and blood cell trauma through the defect. Chronic paravalvular leaks, especially if they are large enough to be clinically significant, may be easy to identify and can be oversewn, especially if they are along the anterior mitral annulus or the non-coronary aortic annulus, or plugged percutaneously. If the leak is confined to the non-coronary sinus, pledgeted mattress sutures can be placed through the sewing ring then outside the aorta to close the defect. Leaks along the posterior mitral annulus or below the coronary ostia following aortic replacement are difficult to identify and repair primarily, necessitating valve removal and replacement in many cases. With this, unfortunately, comes the risk of even more leaks the second time around. Thus, the decision to go back and fix a small perivalvular leak should not be taken lightly, and the consequences of a persistent small leak are expected to be minimal. Small jets are not infrequent on intraoperative transesophageal echocardiography, with an incidence of 10% to 18% after aortic and 4% to 23% after mitral valve replacement. O’Rourke and colleagues found that these small leaks disappeared or remained the same and without clinical consequence at late follow-up in nearly all patients. The size and incidence of visible jets will decrease by 50% following heparin reversal with protamine. Unfortunately, it may be difficult to correlate the echo finding of a small leak with gross operative findings. Moderate or large jets that persist following reversal of protamine should be addressed by immediate re-repair.
What complication is often associated with the leaflet decalcification technique for aortic valve regurgitation repair?
Leaflet decalcification, particularly for patients with rheumatic heart valve disease, has been associated with early failure. Although intraoperative appearance and early postoperative function may be satisfactory, manual mechanical and/or ultrasonic techniques have been uniformly unsuccessful. Leaflet retraction with progressive central regurgitation and progressive recalcification has been the consistent and unsatisfactory result.
A number of different techniques may be employed to reconstruct aortic valves. When leaflet edges are rolled and deficient, or where valve cusps have been destroyed by endocarditis, cusp extension with pericardium may produce a competent valve with acceptable durability. In cases where leaflets are prolapsed, resection and reanastomosis of valve leaflets may restore leaflet coaptation. Patch repair with pericardium has worked well for healed endocarditis with residual leaflet perforation. Aortic regurgitation may be secondary to aortic dilation. Poor coaptation of otherwise normal leaflets results when there is progressive aneurysmal dilation of the circumference of the aorta at the top of the valve commissures (sinotubular junction). In this circumstance, aortic root remodeling may be effective when normal size relationships between valve annulus and sinotubular junction are restored. Techniques to tailor dilated aortic sinuses add complexity, but stable repairs have been demonstrated. Resuspension of prolapsed commissures and reapproximation of dissected sinus tissue is commonly performed for ascending aortic dissections.
What is the incidence of late endocarditis after mitral repair?
What about the incidence for thromboembolic events?
The incidence of late endocarditis is less than 1% per year after mitral valve repair.
Thromboembolic events have been notably infrequent in all series, and the total incidence of thromboembolism is less than 5% at seven year followup.
Is mitral valve repair more likely to fail for degenerative disease or rheumatic disease?
Compared to degenerative disease, mitral valve repair for rheumatic disease is associated with an increased incidence of valve failure over seven years of follow-up.
Can a Ross be performed in the following scenarios:
* 3v CAD
* Marfan syndrome
* bicuspid pulmonic valve
* bacterial endocarditis
In the setting of advanced coronary disease, long-term survival is determined by the natural history of the coronary disease rather than the durability of the aortic prosthesis. A Ross operation cannot add longevity in this setting, and the additional operative complexity compared with prosthetic aortic valve replacement is not warranted.
The Ross procedure should not be performed when there is an underlying defect in connective tissue, such as Marfan syndrome. The fate of the autograft will be similar to the native aortic valve, and long-term success is unlikely.
Finally, autotransplantation of an abnormal pulmonic valve, such as one that is bicuspid, is contraindicated because, again, a long lasting result is unlikely.
The Ross can be done in endocarditi.
A patient has 98% stenosis of the circumflex coronary artery. A positron emission tomography (PET) scan shows a matched perfusion defect and metabolic defect (using fluorodeoxyglucose) of the lateral wall. The distal circumflex system is poorly visualized but it was a large vessel on an angiogram five years ago.
How do you interpret this?
PET scan demonstrated a matched perfusion and metabolic defect of the lateral wall. This means that the lateral wall is scarred and is unlikely to improve with angioplasty or coronary artery bypass.
A 67 year old man presents with new onset atrial fibrillation and pulmonary edema. His dyspnea resolves with medical treatment. He is found to have an ejection fraction of 20% and an end-systolic left ventricle diameter of 45 mm. He has a cardiac index of 1.7 L/min/m2, aortic stenosis with a mean systolic gradient of 30 mmHg (valve area 0.9 cm2), and 98% stenosis of the circumflex coronary artery. A positron emission tomography (PET) scan shows a matched perfusion defect and metabolic defect (using fluorodeoxyglucose) of the lateral wall. The distal circumflex system is poorly visualized but it was a large vessel on an angiogram five years ago. The best surgical recommendation is?
Think through each diagnosis and decision - do they need valve surgery or an angioplasty? Do they need revasc? What about the AF? Do they need a bio or mech valve?
Aortic valve replacement is indicated. Despite a 20% ejection fraction the left ventricle is not excessively dilated (end-systolic left ventricular diameter of 45 mm). Balloon valvuloplasty of the aortic valve, at best, is a short-term solution and longer-lasting benefit is appropriate in a 67 year old patient.
The patient has new onset atrial fibrillation, and is likely to benefit from operation both in terms of survival and symptomatic benefit. Cardioversion and maintenance of sinus rhythm are likely to be achieved, can consider PVI.
Revascularization alone or combined with aortic valve replacement is unlikely to benefit the patient because the PET scan demonstrated a matched perfusion and metabolic defect of the lateral wall. This means that the lateral wall is scarred and is unlikely to improve with angioplasty or coronary artery bypass.
Patients over age 65 years with combined valve and coronary disease are unlikely to need valve re-replacement if a bioprosthesis is utilized. In this 67 year old man with a diminished ejection fraction and coronary artery disease, a mechanical prothesis is not necessary. Avoidance of anticoagulation is desirable in a patient of this age.
What is a key complication when considering chordal shortening for mitral valve repair for regurgitation?
High risk of mitral valve regurgitation.
Techniques for mitral valve anterior leaflet repair include: (1) triangular resection of anterior leaflet tissue; (2) replacement of chords with artificial material (e.g., Goretexþ suture); (3) chordal shortening; and (4) chordal transposition from the posterior leaflet with subsequent posterior leaflet repair. When performing triangular resection of the anterior leaflet, the adjacent intact chordae are identified, and triangular resection is performed to remove the redundant, flail, or prolapsing segments of the leaflet and any ruptured chordae. This technique is particularly useful when a large amount of redundant anterior leaflet tissue is present. Late results have been excellent, with a 5-year durability of 93%. Chordal replacement with polytetrafluoroethylene (Goretexþ) sutures has also had excellent durability. A report by Phillips compared chordal replacement to chordal shortening in 121 patients. The risk of reoperation at 3.5 years due to repair failure was 14.8% in the chordal shortening group compared to 1.4% in the chordal replacement group. Shortening elongated chordae by burying or reimplantation into the tip of a papillary muscle, or by imbricating the insertion on the free edge of the leaflet were initial techniques described for repair of anterior leaflet prolapse. However, chordal transposition has been used more frequently and probably is more reliable. In the transfer technique a segment of normal posterior leaflet directly opposite the prolapsed anterior leaflet is identified and the margins of the portion to be transposed are approximated with sutures. A quadrangular excision of the coapted posterior leaflet with the attached chordae is performed. The margins of the mobilized leaflet segment and anterior leaflet then are sewn together, providing structural support. The quadrangular defect in the posterior leaflet then is repaired in standard fashion. Smedira compared chordal transfer to chordal shortening in 108 patients. The five-year freedom from reoperation was 90-96% after chordal transfer and 74% after chordal shortening. Thus, of the techniques listed, chordal shortening is associated with the highest risk of recurrent mitral valve regurgitation.
A 47-year old woman presents with shortness of breath and fatigue. Physical examination reveals a systolic murmur. EKG shows sinus rhythm at a rate of 70 beats per minute. Chest X-ray shows cardiomegaly. Transthoracic echocardiogram is notable for mild right ventricular dysfunction, left ventricular ejection fraction of 50%, 4+ mitral regurgitation and 2-3+ tricuspid regurgitation. The patient is scheduled for mitral and tricuspid valve repair. Before incision, intraoperative transesophageal echo demonstrates 3+ mitral regurgitation and 1+ tricuspid regurgitation. The best strategy at this point is?
Continue with the plan.
Intraoperative downgrading of severity of mitral and tricuspid regurgitation is common. This is related to changes in preload and afterload associated with general anesthesia and relative hypovolemia. The patient has clear indications for surgery, including symptoms of heart failure, reduced left ventricular function, and both mitral and tricuspid regurgitation. The decision to operate is based upon these findings on preoperative transthoracic echocardiogram. Both the mitral and tricuspid valves should be addressed at the time of operation. Repair is preferable to replacement. If valve repair proves impossible, valve replacement may be performed. In preoperative discussions, the patient should specify the type of replacement prosthesis should repair be impossible.
After SAVR w/ bio valve, when is a thromboembolic event likely to occur?
The decision to administer warfarin for the first three months postoperatively has generally been based on circumstantial evidence showing that nearly 50% of all thromboembolic episodes occur during the first six weeks after surgery. However, no rigorous data suggests that warfarin therapy during this period decreases the thromboembolic risk. In a 10-year study from Yale, Moinuddeen and coauthors concluded that early anticoagulation with heparin and warfarin offered no advantage in preventing early cerebral ischemic events following biologic aortic valve replacement. Long-term valve function and survival were not adversely impacted by withholding early anticoagulation. In addition, there was no benefit or disadvantage associated with the addition of aspirin. This study also found no disadvantage to the use of early anticoagulation (no increase in bleeding complications or prolonged hospital stay), and they concluded that its use was not inherently dangerous. Chronic warfarin therapy is generally recommended for patients with paroxysmal or persistent atrial fibrillation who do not have a contraindication to anticoagulation. However, anticoagulation for atrial fibrillation is not mandatory, and therapy should be individualized. Atrial fibrillation occurs in 20-40% of patients following cardiopulmonary bypass and is generally well controlled with medications. Following bioprosthetic AVR, patients who are in normal sinus rhythm at the time of discharge do not require anticoagulation. For patients under 65 years of age with chronic atrial fibrillation but no other risk factors that would benefit from anticoagulation (prior transient ischemic attacks, stroke, hypertension, poor left ventricular function, rheumatic mitral disease), anticoagulation with aspirin is sufficient. Endocarditis prophylaxis is indicated for all procedures potentially associated with bacteremia. This includes all dental, urologic, and gastrointestinal procedures. The need for endocarditis prophylaxis is life-long, and the recommendations apply to patients following valve repair with a prosthetic implant.
After a bio-SAVR, if anticoagulating for the valve alone, is IV heparin required to bridge?
Early inhibition of protein C can have a prothrombogenic effect in patients prone to a hypercoagulable state. However, the standard cardiac surgical patient is not at risk for this complication. Therefore, intravenous heparin during oral warfarin loading is not mandatory. Following mechanical or bioprosthetic valve replacement, routine initial heparinization remains optional, unless the patient is in persistent atrial fibrillation (greater than 24-48 hours). If initiating warfarin must be postponed more than 3-4 days (for example, while awaiting pacemaker placement), then IV heparin should be considered. Few studies focus solely on anticoagulation following bioprosthetic valve replacement.
A patient has SAM postop MVr, not responding to medical therapy. What can be done?
Systolic anterior motion of the mitral valve leading to aortic outflow tract obstruction is a well recognized complication of mitral valve repair. It is caused by a repair that leaves the coaptation point of the anterior and posterior leaflet too anterior toward the aortic valve and sometimes by too small of a annuloplasty ring. It is seen in patients with a large, redundant posterior leaflet. In this case, this was was not recognized. An appropriate initial action would have been to initially perform a sliding plasty of the posterior leaflet and a larger annuloplasty ring (do not try to undersize the ring to improve MR).
Given that this was not done, reasonable options (after failure of medical management including volume loading, removal of inotropes, beta-blockade, etc.) include return to the operating room to redo the repair with a larger ring and a sliding plasty or mitral valve replacement with a low-profile mechanical valve.
A patient underwent composite replacement of the aortic valve, root, and ascending aorta. Cardiopulmonary bypass was discontinued and protamine was administered. Excessive bleeding is noted from the anastomosis between the aortic graft and left coronary artery button. The ACT and platelet count are normal.
What do you do?
resume bypass and redo the anastomosis
In situations which involve continued bleeding from an anastomosis despite appropriate reversal of clotting abnormalities, especially when simple topical measures seem ineffective, it is usually necessary to insert additional sutures or to take down and redo the anastomosis in order to achieve hemostasis. In the difficult area described, reinstitution of bypass and suture line revision is indicated as the safest method of resolving the problem.
The inclusion method for vascular repair implies working within the aorta and wrapping residual aneurysm tissue around the graft. Although this method may facilitate the development of a tamponade effect it does result in less secure hemostasis. Direct coronary anastomoses (no buttons) were features of initial aortic root reconstructions, but creation of buttons and direct implantation are now favored. Wrapping is not recommended to apply pressure to a coronary button-aortic anastomosis because of distortion and compression. This is not really possible because there is usually no intact aortic tissue near this area since creation of coronary buttons results in destruction of local aortic root architecture.
Is tricuspid regurgitation usually secondary to LHF or intrinsic disorder of the valve? What does this mean in terms of operative decision making?
Tricuspid regurgitation is more often secondary to left heart failure than to organic disorders of the tricuspid valve itself. Annular dilation produces tricuspid regurgitation as the consequence of elevated right ventricular pressures. This rarely requires leaflet reconstruction and can most often be repaired with annuloplasty alone.
In contrast, myxomatous degeneration of the mitral valve is the most common indication for repair, which often requires leaflet reconstruction in addition to annuloplasty. The tricuspid annulus is less distinct and often more friable than the mitral annulus, making it more difficult to identify visually during valve repair. Functional dilation of the tricuspid valve involves the anterior two-thirds of the annulus, including both the anterior and posterior leaflets. The septal leaflet is attached to the fibrous skeleton of the heart and does not dilate. Dilation occurs with a 2:1 ratio in the posterior versus anterior leaflet, necessitating inclusion of the posterior leaflet during tricuspid annuloplasty. In contrast, functional dilation of the mitral valve occurs mainly in the posterior leaflet, since the anterior annulus is relatively fixed between the fibrous trigones. Mitral partial band annuloplasty must include the posterior leaflet only, as long as the ends of the band are secured to the fibrous trigones. Tricuspid valve repair can be performed safely in an empty, beating heart following completion of a mitral valve procedure and removal of the aortic cross-clamp.
However, while generally less safe, it is also possible to perform mitral valve repair in an empty, beating heart.
When mitral valve repair is performed via right anterior thoracotomy in patients with a relative contraindication to median sternotomy, the left side of the heart can be opened while the heart beats, as long as aortic pressure is maintained and the ventricle is kept empty to avoid systemic air embolization. Mitral valve leaflets can be separated into two (anterior leaflet) or three (posterior leaflet) distinct zones: (1) Distal rough zone, which represents the zone of coaptation and receives the insertion of the chordae tendineae on its ventricular surface, (2) Proximal clear zone, which has no chordal attachments, and (3) Basal zone (only posterior leaflet) which receives tertiary chordae tendineae directly from the ventricular surface. Tricuspid valve leaflets also can be separated into three distinct zones, but all zones receive chordal attachments.
Is it possible to complete a mitral valve in a beating heart?
While generally less safe, it is also possible to perform mitral valve repair in an empty, beating heart.
When mitral valve repair is performed via right anterior thoracotomy in patients with a relative contraindication to median sternotomy, the left side of the heart can be opened while the heart beats, as long as aortic pressure is maintained and the ventricle is kept empty to avoid systemic air embolization.
What are the anatomic zones of the mitral and tricuspid valves as they relate to the chordae tendineae?
Mitral valve leaflets can be separated into two (anterior leaflet) or three (posterior leaflet) distinct zones: (1) Distal rough zone, which represents the zone of coaptation and receives the insertion of the chordae tendineae on its ventricular surface, (2) Proximal clear zone, which has no chordal attachments, and (3) Basal zone (only posterior leaflet) which receives tertiary chordae tendineae directly from the ventricular surface. Tricuspid valve leaflets also can be separated into three distinct zones, but all zones receive chordal attachments.
A patient suffered an embolic stroke to the right hemisphere in the distribution of the right middle cerebral artery, which caused left-sided paralysis. The patient has a mitral valve endocarditis and is in heart failure.
When should surgery be done?
In general, surgeons should wait 1 to 2 weeks before performing cardiac surgery. However, early surgery is indicated for heart failure (Class 1B), uncontrolled infection (Class 1B), and to prevent embolic events (Class 1B/C). After a stroke, surgery should not be delayed as long as coma is absent and cerebral hemorrhage has been excluded by cranial CT scan (Class 2A Level B). After a TIA or silent cerebral embolism, surgery is recommended without delay (Class 1 Level B). If intracranial hemorrhage is seen on CT scan, surgery must be postponed for at least 1 month (Class 1 Level C). Every patient should have a repeat head CT scan before the operation to rule out preoperative hemorrhagic transformation of a brain infarct. The presence of hemorrhage warrants neurosurgical consultation and consideration of cerebral angiography to rule out a mycotic aneurysm. Surgery can be performed relatively safely within 3 days of a stroke if heart failure is severe. Otherwise, a delay of 1 to 2 weeks is preferable. In patients with associated hemorrhage, a delay of at least 4 weeks is preferred. There is still controversy.
A 23-year-old woman underwent tetralogy of Fallot repair as a child and pulmonary valve replacement with a size 23 tissue valve. She now presents with Candida albicans endocarditis of the pulmonary valve. She has experienced multiple septic pulmonary emboli. Her pulmonary artery pressure is 45/23 mmHg. She is receiving IV antibiotics, but the signs and symptoms of endocarditis persist. She is a candidate for reoperation. The best management is?
Replacement of the infected pulmonary valve with a homograft and removal of all infected material has a good chance of success.
Pulmonary valve endocarditis, either native or prosthetic, is an uncommon problem. When antimicrobial treatment fails, then operative management is indicated. Debridement of all infected material and tissue is necessary in all cases. However, in this case with pre-existing pulmonary artery hypertension valvectomy (without replacement) would not be expected to be successful due to the limitations of forward flow. Percutaneous approaches have been employed more recently, but they do not allow for operative debridement and removal of infected material. Replacement with a mechanical valve would mandate anticoagulation, which is not desirable for this young woman of child-bearing age.
This is a preop cath for mitral repair. A previous XR shows severe mitral calcification. What must you be careful of during this operation?
This patient has severe mitral annular calcification (MAC). Additionally, the circumflex runs adjacent to the bar of calcium. Catheterization reports may not specify the relationship of the circumflex coronary to the atrioventricular groove, but the variability of this anatomy and the technical challenges presented by MAC can be daunting. Thoughtful preoperative review of all data is key to planning regarding recognized problems and contingencies.
A variety of techniques can be used intraoperatively to manage MAC, but it does place the patient at increased risk for atrioventricular disruption, paravalvular leaks, myocardial infarction, and reoperation. Left dominant coronary anatomy presents increased risks for circumflex coronary complications because of suture placement.
