Cardiac Surgery

Cardiac Surgery

Cardiac Surgery

  1. Ischemic Heart Disease- perfusion demand deficit or mismatch. The heart is an end organ that perfuses the entire body with blood as well as itself. 80% of blood flow to the heart itself occurs during diastole.
  2. Causes of ischemic heart disease

  1. Atherosclerotic cardiovascular disease
  2. Valvular heart disease
  3. Vasculitis
  4. Congenital coronary anomalies
  5. Dissection of the Thoracic aorta
  6. Myocardial ischemia- very important to give aspirin for this reason

  1. Common Symptoms and Signs of Ischemic Heart Disease
  2. Respiratory changes

  1. Dyspnea
  2. Orthopnea
  3. Paroxysmal nocturnal dyspnea
  4. SOB

  1. Chest pain or discomfort
  2. Palpitations
  3. Fatigue
  4. Presyncope
  5. Syncope
  6. Changes in heart rate or blood pressure

Anxiety, diaphoresis. Cyanosis or pallor may accompany any of the symptoms. Any combination is possible.

  1. Diagnostic Evaluation of Ischemic Heart Disease- If the index of clinical suspicion is high. Further diagnostic studies are necessary.
  2. ECG- look for changes acute and chronic
  3. Acute ECG changes may include, Q waves, ST segment elevations, T wave inversions, and QT prolongation
  4. Chronic forms of ischemia may produce similar ECG findings often coexisting with persistent chest pain
  5. Exercise stress testing
  6. Echocardiogram- can show wall hypertrophy and chamber size
  7. Left heart catheterization- dye contrast study remains the gold standard in the diagnosis of ischemic heart disease. Can help to determine if coronary artery or valvular heart disease is present.
  8. Ejection fraction- dye is injected into the left ventricular cavity to evaluate left ventricular function
  9. Treatment of Ischemic Heart Disease
  10. Medical management- CCB, BB, vasodilators
  11. Percutaneous transluminal coronary angioplasty (PTCA)- AKA- balloon angioplasty; with or without stent placement
  12. Typically performed in catheterization lab and is used more often than CABG
  13. 20-30% chance of recurrence; 1/3 reanastamosis
  14. Surgical treatment- coronary artery bypass grafting (CABG)
  15. Indications: include failure with medical management techniques, lab evidence of continued ischemia (ex. liver enzymes, ABG), ejection fraction <30-40%, continued exercise intolerance, Q wave infarction, evidence of more than mild ischemia, multi-vessel disease
  16. Complications
  17. Hypotension
  18. Hypovolemia
  19. Cardiac tamponade
  20. Heart failure
  21. Infection- pneumonia, urinary sepsis, superficial or deep infection in surgical wounds, mediastinitis
  22. Microembolization and stroke- occurs in about 1% of patients. In the elderly, incidence may increase to 6% to 8%
  23. Respiratory failure- especially in patients with underlying pulmonary disease
  24. Renal insufficiency or renal failure

* Essentially all organ systems can be affected by complications of CABG and the physiologic disruptions associated with the heart-lung machine. The possibility of these complications contributed to the movement to explore less invasive methods of coronary revascularization without coronary pulmonary bypass. (CABG on the beating heart)

  1. Prognosis- at most major centers, the mortality rate is about 2% to 4% for patients who undergo CABG
  1. Minimally invasive CABG
  2. laparoscopic CABG- performed through a limited # of incisions without the sue of cardiopulmonary bypass
  3. More extensive revascularization is performed through a standard or modified sternotomy incision
  4. Advantages- decrease pain, shorter recovery period, decrease chance of wound infection

Valvular Heart Disease

-Methods for repair have been available since the 50’s and 60’s. The invention of the heart/lung machine has increased patient survival. Mitral stenosis was among the first to be treated. Dr. Starr performed the first successful valve replacement surgery.

  1. Diagnosis of Valvular Heart Disease
  2. Non-invasive
  3. ECG- may be normal, suggestive of LVH, or repolarization changes
  4. Echocardiography or echo Doppler studies
  5. Invasive- cardiac catheterization- definitive diagnostic procedure
  6. Aortic Valve Disease- most common surgical valve lesion in developed countries
  7. Aortic stenosis- progressive, usually clinically silent until signs of CHF develop. CLASSIC TRIAD of symptoms (angina, heart failure, syncope) eventually without intervention. The mortality rate approaches 100% within 5 years of the onset of symptoms. These symptoms of failure may appear suddenly or gradually progress
  8. Causes of aortic stenosis

  1. History of rheumatic fever
  2. Progressive valvular calcification
  3. Congenital cause

  1. Signs and symptoms of aortic stenosis
  2. Systolic ejection murmur at the aortic area transmitting to the neck and apex. In severe cases, there may be a palpable left ventricular heave or thrill
  3. Angina pectoris
  4. Syncope
  5. SUDDENC DEATH- rarely the initial symptom in previously asymptomatic patients
  6. Treatment of aortic stenosis
  7. Valve replacement surgery should be offered to symptomatic patients
  1. Aortic regurgitation- symptoms can be silent, even in the presence of massive cardiac enlargement the patient may not develop significant symptoms
  2. Causes of aortic regurgitation
  3. Marfan’s syndrome
  4. Scarring from valvulitis of rheumatic heart disease
  5. Valvular damage from bacterial endocarditis

* Acute regurgitation related to aortic dissection or acute bacterial endocarditis is poorly tolerated and can lead to death without early or even emergency treatment

  1. Signs and symptoms of aortic regurgitation
  2. Usually asymptomatic
  3. Soft, aortic diastolic murmur
  4. Exertional dyspnea and fatigue
  5. Angina or atypical chest pain
  6. PND or pulmonary edema
  7. Wide pulse pressure- elevated systolic and low diastolic pressure
  8. Treatment of aortic regurgitation
  9. Valve replacement surgery should be offered to symptomatic patients. Medical treatment with vasodilators and beta-blocker therapy may postpone the need for surgical intervention
  1. Mitral stenosis- among the 1st acquired heart diseases treated by surgery
  2. Causes of mitral stenosis
  3. Rheumatic heart disease- scarring
  4. Signs and symptoms of mitral stenosis
  5. Localized mid-diastolic low pitched murmur- because the valve is thickened, it opens in early diastole with an OPENING SNAP
  6. Fatigue of exertion
  7. PND and orthopnea as right heart failure progresses
  8. Long standing pulmonary venous hypertension may precipitate development of bronchial submucosal varices- rupture may cause hemoptysis
  9. Paroxysmal or chronic atrial fibrillation- rate MUSRT be controlled or may precipitate dyspnea or pulmonary edema
  10. Treatment of Mitral stenosis- indication include, uncontrollable pulmonary edema, limiting dyspnea and intermittent pulmonary edema, evidence of pulmonary hypertension with right ventricular hypertrophy or hemoptysis, limitation of activity despite ventricular rate control and medical therapy and recurrent systemic emboli despite anticoagulation with moderate or severe stenosis
  11. Open mitral commissurotomy- may be used if there is no significant concurrent regurgitation
  12. Valve replacement surgery should be offered to patients with significant valve distortion or calcification and when there is presence of stenosis and regurgitation
  13. Mitral Regurgitation- may be asymptomatic for many years or for life. Can lead to left sided heart failure.
  14. Causes of mitral regurgitation
  15. Connective tissue diseases/Marfan’s syndrome
  16. Infective endocarditis/rheumatic heart disease (mixed picture-s stenosis and regurgitation)
  17. Sub-valvular dysfunction- ruptured chordae tendinae
  18. Papillary muscle dysfunction following MI
  19. Myxomatous degeneration- myxoma- benign tumor composed of primitive connective tissue cells and stroma- rare cause of mitral regurgitation
  20. Signs and symptoms of mitral regurgitation
  21. Pansystolic murmur maximal at apex- may radiate to axilla, prominent 3rd heart sound may be heard
  22. Exertional dyspnea and fatigue, which may progress gradually over years
  23. May predispose to infective endocarditis
  24. Treatment of mitral regurgitation
  25. Early surgical intervention is necessary to prevent progressive and irreversible damage to the left ventricle; there is better preservation of left ventricular function if intact valve repair can be done. Vale replacement should be offered if repair is not possible
  26. Tricuspid Valve Disease- isolated disease of the tricuspid valve is rare. Usually, tricuspid disease is associated with pulmonary hypertension and concomitant mitral valve disease. May be isolated finding in IV drug users where tricuspid endocarditis is present.
  27. Causes of tricuspid valve disease- usually rheumatic in origin. Other causes may included, SLE, myxomatous degeneration, and congenital anomaly
  28. Signs and symptoms of tricuspid valve disease
  29. diastolic rumble along left sternal border identical to mitral stenosis
  30. Signs or right heart failure, right ventricular overload- including hepatomegaly, ascites, and dependent edema
  31. Treatment of tricuspid valve disease
  32. Excision of the valve without valve replacement can be achieved in the absence of pulmonary hypertension- use for patients with tricuspid endocarditis
  33. valve replacement surgery should be offered

Heart valves

- Must be careful not to sew in too tightly- can cause conduction problems

- Replacement is not curative- replaces one disease for another

  • Prosthetic endocarditis
  • Thromboembolism
  • Bioprosthetic deterioration around 10 years

-2 types- mechanical and bioprosthetic

  • Mechanical- 3 types- leaflet used most often; more durable and rarely require replacement
  • Disadvantage is that they are noisy and require lifelong anticoagulation with coumadin
  • If less than 70 years old the patient should be offered mechanical valve replacement
  • Bioprosthetic- use if life expectancy 10 years of less or women who plan to have children use xenograft or homograft
  • Xenograft- another species; least durable
  • Homograft- cadaver; somewhat durable; lowest thrombogenicity and prosthetic endocarditis
  • Autograft- repositioning of your own valves; somewhat durable; lowest thrombogenicity and prosthetic endocarditis

Comparison of Prosthetic Heart Valves

Mechanical Valves / Bioprosthetic Valves
Durability / ++ / +/-
Thromboembolism / - / +
Obstruction in small sizes / + / -
Calcification with age / + / -
Calcification with dialysis / + / -

Congenital Heart Disease

  1. Ventricular Septal Defect- most common congenital heart defect in muscular. Ventricular septal defects can occur anywhere in the muscular septum. They are classified by location. The lesion is acyanotic with increased pulmonary blood flow. Antibiotic prophylaxis is MANDATORY; these patients are at risk for infective endocarditis.
  2. Signs and symptoms of ventricular septal defect
  3. Adults may be asymptomatic if defect is small to moderate
  4. II- V/VI holosystolic murmur heard best at the 2nd and 3rd IC spaces along the sternal border, often associated with a systolic thrill
  5. Large defects are associated with early left ventricular failure
  6. Chronic, moderate left to right shunts may lead to pulmonary vascular disease and right sided failure
  7. Treatment of ventricular septal defect(s)- defects causing large shunts should be repaired using prosthetic patches
  8. Complications of ventricular septal defect repair- heart block may be produced by sutures. The AV node, bundle of His an/or RBB may be damaged by sutures placed too deeply
  9. Patent Ductus Arteriosus- second most common congenital heart defect- acyanotic with increased pulmonary blood flow. Antibiotic prophylaxis is MANDATORY due to increased risk of infective endocarditis
  10. Signs and symptoms of Patent Ductus Arteriosus
  11. Adults may be asymptomatic if defect is small or moderate
  12. Continuous rough “machinery” murmur in late systole heard best at the 1st and 2nd IC spaces along the left sternal border, may be associated with systolic thrill- usually not present unless left ventricular failure or pulmonary hypertension exists
  13. Treatment of Patent Ductus Arteriosus- in uncomplicated cases, surgical ligation with multiple ties. In large defects, the patent ductus may be divided and oversewn on the ends. You must protect the recurrent laryngeal nerve during this procedure to prevent loss of voice
  14. Atrial Septal Defect(s)- third most common congenital heart defect
  15. Signs and symptoms of atrial septal defects
  16. Usually asymptomatic until middle age
  17. I-III/VI systolic ejection murmur heard best at 2nd and 3rd IC space parasternally, with wide split of S2 that does not vary with breathing
  18. Exertional dyspnea if large defect and cardiac failure is present
  19. Treatment of atrial septal defect- elective surgical repair with a prosthetic patch is indicated for large defects at 3-5 years of age to protect against late pulmonary hypertension
  20. Complications of atrial septal defect repair- complete heart block if sutures placed to anchor the graft are placed too close to the conduction system in the atria. Other complication may include patch leaks and mitral regurgitation or stenosis
  21. Transplantation
  22. Must respect religious beliefs
  23. Someone must die