CPB strategies for patients with previous valve replacment#.pptx

Cpb manegement for redo valve surgery

1. CPB Strategies for Patients with Previous Valve Replacement Surgery SUBMITTED T0 -: DR UJJWAL CHOWDHARY SUBMITTED BY-: ABHISHEK NAIR AND SHAMAPRAWEEN 3 RD AND 2 ND year

2. INTRODUCTION Cardiopulmonary bypass (CPB) is a technique used during heart surgery to support the heart and lungs while the surgeon performs repairs or replacements. Heart valve replacement surgery is a surgical procedure designed to repair or replace a damaged or malfunctioning heart valve. This procedure is typically performed when a heart valve is unable to function properly, leading to various heart problems such as heart failure, arrhythmias, or stroke. For patients who have previously undergone heart valve replacement, CPB strategies can be particularly challenging due to the potential for complications related to the existing valve and the surgical history .

3. WHAT ARE HEART VALVES The heart consists of four chambers, two atria (upper chambers) and two ventricles (lower chambers). There is a valve through which blood passes before leaving each chamber of the heart. The valves prevent the backward flow of blood. These valves are actual flaps that are located on each end of the two ventricles (lower chambers of the heart). They act as one-way inlets of blood on one side of a ventricle and one-way outlets of blood on the other side of a ventricle. Normal valves have three flaps, except the mitral valve, which has two flaps. The four heart valves include the following: tricuspid valve:  located between the right atrium and the right ventricle pulmonary valve:  located between the right ventricle and the pulmonary artery mitral valve:  located between the left atrium and the left ventricle aortic valve:  located between the left ventricle and the aorta

4. HEART VALVES

5. NORMAL FUCTIONING OF HEART VALVE As the heart muscle contracts and relaxes, the valves open and shut. This lets blood flow into the ventricles and atria at alternate times. Here is a step-by-step description of how the valves work normally in the left ventricle: When the left ventricle relaxes, the aortic valve closes and the mitral valve opens. This lets blood flow from the left atrium into the left ventricle. The left atrium contracts. This lets even more blood to flow into the left ventricle. When the left ventricle contracts, the mitral valve closes and the aortic valve opens. This is so blood flows into the aorta and out to the rest of the body. While the left ventricle is relaxing, the right ventricle also relaxes. This causes the pulmonary valve to close and the tricuspid valve to open. This lets blood flow into the right ventricle that was returned to the right atrium from the body. When the left ventricle contracts, the right ventricle also contracts. This causes the pulmonary valve to open and the tricuspid valve to close. Blood flows out from the right ventricle to the lungs before it is returned to the left atrium as fresh, oxygenated blood.

6. VALVULAR HEART DISEASE There are different types of heart valve disease, and it is possible for more than one valve to be affected. Valvular stenosis With valvular stenosis, the tissues forming the valve leaflets become stiffer, narrowing the valve opening and reducing the amount of blood that can flow through it. Mild narrowing may not reduce the overall functioning of your heart. However, the valve can become so narrow (stenotic) that it reduces your heart’s function, makes your heart pump harder and puts it under strain. As a result, the rest of your body may not get enough blood flow. Valvular insufficiency Valvular insufficiency (or regurgitation, incompetence, "leaky valve"), happens when the leaflets don’t close completely, letting blood leak backward across the valve. This backward flow is referred to as “regurgitant flow.” Your heart has to pump harder to make up for this backward flow, and the rest of your body may get less blood flow. You can get a backward flow if you have mitral valve prolapse, a common problem in which the valve flaps go back into your left atrium when your heart beats. Valvular atresia Valvular atresia happens when a heart valve doesn’t form correctly before birth. This is usually diagnosed very early in infancy.

7. VALVE REPLACEMENT SURGERY Valve replacement surgery is a surgical procedure to replace a damaged or diseased heart valve with an artificial valve. This procedure is typically performed to treat severe heart valve disease, such as stenosis or regurgitation. Types of Valve Replacement There are two main types of valve replacements: Mechanical valve: Made of durable materials like metal or carbon, mechanical valves are long-lasting and require lifelong anticoagulant medication to prevent blood clots. Biological valve: Made from tissue, either from a pig or cow (heterograft) or from a human donor (homograft). Biological valves are generally less durable than mechanical valves but do not require lifelong anticoagulation.

8. MECHANICAL VALVE Mechanical valves are often used in heart valve replacement surgeries and come in several types. Here are the main types and their typical lifespan: Types of Mechanical Valves Ball-and-Cage Valves Description: Consists of a ball that moves within a cage. Lifespan: Very durable, often lasting 15-20 years or longer. 2.Tilting Disc Valves Description: Features a disc that tilts open and closed. Lifespan: Typically lasts 10-20 years, with some lasting even longer. 3.Bileaflet Valves Description: Contains two leaflets that open and close. This type is commonly used today. Lifespan: Generally lasts 15-25 years, with many lasting beyond that.

9. BIOPROSTHETIC VALVES Bioprosthetic valves, also known as tissue valves, are heart valves made from animal tissues or human tissues. They are an alternative to mechanical valves and are often used in patients who may not tolerate long-term anticoagulation therapy. Here are the main types of bioprosthetic valves : Types of Bioprosthetic Valves Porcine Valves Description: Made from pig heart valves. Often treated to reduce the risk of rejection. Usage: Commonly used for aortic and mitral valve replacements. Bovine Valves Description: Derived from cow pericardium (the membrane surrounding the heart). Usage: Often used in aortic and mitral positions, offering good durability.

10. 3.Human Donor Valves Description: Obtained from deceased human donors (homografts or allografts). Usage: Typically used in cases of endocarditis or complex heart repairs; they are less common for standard replacements. 4.Pericardial Valves Description: Made from treated pericardial tissue (usually bovine). Usage: Used in various locations, including the aortic position; they offer good hemodynamic performance. Durability and Lifespan Typical Lifespan: Bioprosthetic valves usually last about 10-15 years, though some newer models may last longer. Factors like patient age, health, and lifestyle can influence longevity. Advantages: Lower risk of thromboembolism compared to mechanical valves, reducing the need for long-term anticoagulation. Better hemodynamics and more natural function. Disadvantages: Generally less durable than mechanical valves, leading to potential reoperation. Risk of calcification over time, especially in younger patients .

11. Reason for patients with Valve replacement surgery need another replacement surgery Patients with valve replacement surgery may require another replacement surgery for several reasons: 1. Structural Degeneration: Over time, both mechanical and biological valves can degenerate. Biological valves, made from animal tissue, are particularly prone to calcification and wear, leading to stenosis (narrowing) or regurgitation (leakage). 2. Thrombosis: Mechanical valves carry a risk of thrombus formation. If a clot forms on the valve, it can lead to obstruction or embolic events, necessitating replacement. 3. Infection (Endocarditis): Valve prostheses can become infected, leading to endocarditis. This infection can damage the valve and surrounding structures, requiring surgical intervention. 4. Hemolysis: Mechanical valves can cause hemolysis (destruction of red blood cells) due to turbulent blood flow, which can lead to complications and the need for replacement.

12. 5. Patient Factors: Conditions such as hypertension, diabetes, or other comorbidities can affect the longevity of a valve and increase the likelihood of needing a replacement. 6. Pannus Formation: In some cases, excessive tissue growth (pannus) around the valve can obstruct its function, necessitating surgical intervention. 7. Valve Size or Positioning Issues: If the initial valve was not the correct size or was improperly positioned, it may not function adequately over time, leading to the need for a replacement. 8. New Symptoms or Changes in Function: Patients may develop new symptoms or changes in their heart function that indicate the need for further intervention. Regular follow-up with echocardiography and clinical assessments can help monitor valve function and detect issues early, potentially preventing the need for more extensive surgeries.

13. CARDIOLULMONARY BYPASS STATEGIES FOR REDO VALVE REPLACEMENT SURGERY Cardiopulmonary bypass (CPB) strategies during valve replacement surgery are crucial for maintaining circulation and oxygenation while the heart is stopped to allow for the precise surgical repair or replacement of the heart valve. CPB temporarily takes over the function of the heart and lungs during surgery. In patients who have previously undergone valve replacement surgery, additional considerations are required because of changes in the heart structure, potential scar tissue, and the presence of prosthetic materials. Here are the key strategies and considerations for CPB in such patients:

14. Preoperative Planning Review of Previous Surgery: Detailed review of the patient’s prior surgical records is essential, including the type of valve used (biological or mechanical), any complications, and the type of incision made. Imaging: Advanced imaging techniques, such as echocardiography, CT, or MRI, are used to assess the anatomy of the heart, the position and condition of the previously replaced valve, and the presence of scar tissue (adhesions). Risk of Adhesions: After previous surgery, there are often significant adhesions (scar tissue) in the pericardium, which can complicate re-entry into the chest and may increase the risk of bleeding or injury to the heart. Surgeons need to plan the incision and dissection carefully to avoid damaging the heart or the previously implanted prosthesis .

15. Anticoagulation Management: Coordinate with the cardiology team to manage anticoagulation therapy preoperatively, particularly for patients on warfarin or direct oral anticoagulants. Multidisciplinary Team: Involve cardiologists, anesthesiologists, and Perfusionists early in the planning process.

16. Intraoperative Strategies CPB Circuit Selection: Use a CPB circuit that minimizes hemolysis and reduces the risk of clotting, especially important for patients with mechanical valves Temperature Management: Consider hypothermia to reduce metabolic demand, but be cautious of its effects on coagulation and myocardial protection. Heparinization Protocol: Ensure adequate heparinization to achieve therapeutic activated clotting time (ACT) before initiating CPB. Monitoring: Employ advanced monitoring techniques, including transesophageal echocardiography (TEE), to assess hemodynamics and valve function during CPB. Minimize Hemolysis: Use appropriate flow rates and avoid excessive turbulence in the CPB circuit to reduce the risk of hemolysis. Choice of Surgical Technique: - Reoperation via Sternotomy: This is the most common approach. Careful dissection is needed to avoid damaging existing structures. - Minimally Invasive Techniques: Depending on the patient’s anatomy and the surgeon's expertise, consider minimally invasive options (e.g., right thoracotomy, robotic-assisted surgery) if feasible.

17. CPB Cannulation Strategy: Peripheral Cannulation: If re-entry into the chest is difficult or if there are concerns about damaging the heart or vessels due to adhesions, peripheral cannulation (such as femoral artery and vein cannulation) may be used to establish CPB before opening the chest. Central Cannulation: If feasible, standard central cannulation (aorta and right atrium) is often preferred, but the presence of scar tissue may make this more challenging. Meticulous dissection is required to avoid injury. Consideration of Previous Valve: In cases where the previous valve is still functional but requires careful protection (e.g., a mechanical valve), surgeons must plan cannulation and aortic cross-clamping to avoid damaging the existing valve or prosthesis.

18. Aortic Cross-Clamping and Cardioplegia Delivery: Aortic Cross-Clamping: The cross-clamp is applied to stop blood flow through the aorta and allow the heart to be stopped. Care must be taken to avoid damaging the previous valve or any prosthetic material near the clamp site. Cardioplegia: Cardioplegia (a potassium-rich solution used to stop the heart) can be delivered through the aortic root if it is accessible and free of adhesions. However, in some patients, adhesions or previous surgery may require alternative strategies such as: Direct coronary ostial cardioplegia: Direct infusion of cardioplegia into the coronary arteries. Retrograde cardioplegia: Delivery of cardioplegia through the coronary sinus (a vein that drains into the right atrium), which may be necessary if the aorta is not suitable for antegrade delivery.

19. Valve Replacement or Repair: Removal of Previous Valve: If the previously replaced valve is malfunctioning (e.g., due to degeneration, thrombosis, or endocarditis), it must be carefully removed. This is particularly complex if there is heavy calcification or if the valve was deeply embedded in the heart tissue. Replacement Valve Selection: A new valve prosthesis is selected based on the patient’s age, condition, and prior valve type. If the patient previously had a biological valve, a mechanical valve may be considered to reduce the need for future surgeries, although this depends on the individual case. Redo Surgery Considerations: Redo valve replacement surgeries carry higher risks than initial surgeries due to factors like scar tissue, the presence of a prosthetic valve, and changes in the heart’s structure. Surgeons must be meticulous to avoid damaging surrounding structures, such as the coronary arteries or conduction system (which could result in heart block requiring a pacemaker).

20. Management of Blood Products and Coagulation: Anticoagulation: Patients with a previously implanted mechanical valve may already be on long-term anticoagulation (such as warfarin). Before surgery, anticoagulation must be reversed to reduce the risk of excessive bleeding. During CPB, heparin is used to prevent clotting in the bypass circuit Coagulopathy: Reoperations and CPB can increase the risk of coagulopathy (bleeding disorders). Surgeons must be prepared for increased blood product use, including packed red blood cells, fresh frozen plasma, platelets, and clotting factors. Techniques such as antifibrinolytic therapy (e.g., using tranexamic acid) may be used to reduce bleeding.

21. Weaning from CPB: Heart Function: After the valve replacement, the heart is restarted, and careful assessment of its function is done before weaning the patient off CPB. In previously operated patients, heart function may be impaired due to the changes in the heart muscle or damage from prior surgeries. Inotropic Support: In some cases, inotropes (medications to strengthen heart contractions) or mechanical circulatory support (like intra-aortic balloon pumps) may be needed to help the heart pump effectively after surgery.

22. Postoperative Care Monitoring for Complications: Postoperatively, careful monitoring is required for complications such as arrhythmias, valve dysfunction, bleeding, and infection. Patients with previously replaced valves may have a higher risk of complications and often need more intensive monitoring and care. Anticoagulation Management: If a mechanical valve is implanted or if the patient had one before surgery, long-term anticoagulation must be restarted to prevent thromboembolic events (e.g., strokes or valve thrombosis). Long-term Follow-up: Schedule regular follow-ups for echocardiographic assessment and management of anticoagulation therapy.

23. Summary of Key CPB Strategies for Valve Re-replacement Careful preoperative planning, including reviewing prior surgery and imaging studies. Consideration of adhesions, scar tissue, and prosthetic valves when selecting the cannulation site and cardioplegia strategy. Protection of the previously implanted valve or prosthesis during surgery. Precise removal of the old valve and selection of an appropriate new prosthetic valve. Meticulous management of anticoagulation and bleeding risks, given the complexities of reoperation. Each reoperative valve surgery is unique, and surgical teams tailor their approach to the individual patient’s anatomy, previous procedures, and overall health condition.

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