Anaesthesia for closed mitral valvotomy

closed mitral valve surgeries

1. DR ZIKRULLAH ANAESTHESIA FOR CLOSED MITRAL VALVOTOMY

2. HEADINGS Anatomy of Mitral valve Pathophysiology of Mitral Stenosis. Indications for Closed Mitral Valvotomy Preanaesthetic assessment Anaesthetic management

3. ANATOMY Two leaflets – Anterior and Posterior. Surrounded by Mitral valve annulus. Anterior cusp takes up larger part of the ring but Posterior leaflet has larger surface area. Normal Orifice = 4-6 cm 2 .

4. Normal Orifice = 4-6 cm 2 . Mild MS = >1.5 cm 2 Moderate MS = 1-1.5 cm 2 Severe MS = <1.5 cm 2

5. Mitral Valve area is calculated using Gorlin’s Equation : Area = Cardiac Output/ (DFP or SEP) (HR) 44.3 C √Δ P DFP = Diastolic Filling Pressure C = Empirical Constant SEP = Systolic Ejection Period Δ P = Pressure Gradient HR = Heart Rate

6. PATHOPHYSIOLOGY

7. Decreased filling ultimately manifests as : Muscle atrophy Inflammatory myocardial fibrosis Scarring of sub valvular apparatus Abnormal pattern of left ventricle contraction Decreased left ventricular compliance with diastolic dysfunction Right to left shift due to pulmonary hypertension

8. USUAL SURGERIES Closed mitral valvotomy Mitral commissurotomy Percutaneous balloon dilatation Mitral valve replacement Non cardiac surgery – most common LSCS

9. INDICATIONS Indications for Closed Mitral Valvotomy – 1) Single valve lesion. 2) Sinus Rhythm 3) No Calcification.

10. Performed through an incision in the left atrial appendage using a purse string technique to prevent blood loss or air embolism. Tubbs dilator is passed into the left ventricle via the apex and then opened within the orifice of the valve.

11. Preanaesthetic assessment Assessment of Severity of cardiac disease Degree of impaired myocardial contractility Presence of associated major organ disease (hepatic, renal & pulmonary) Compensatory mechanisms for maintaining cardiac output ( ↑sympathetic activity, cardiac hypertrophy) Prosthetic heart valves Drug therapy

12. History Cough & dyspnoea : precipitating factors; exertion, excitement, fever, severe anaemia , pregnancy, thyrotoxicosis. Orthopnoea & Paroxysmal Nocturnal Dyspnea Exercise tolerance Pedal edema

13. Heamoptysis Features of emboli: e.g. pulm infections, neurological symptoms. Chest pain:10% patients have anginal type chest pain not attributable to CAD. History suggestive of RVF Raised JVP Hepatic congestion Edema

14. Drug history: Digoxin, Diuretics, Calcium blockers, anti coagulants, β -blockers Hoarseness of voice – Enlarged left atrium, tracheobronchial enlarged lymph nodes, dilated pulmonary artery may all compress Recurrent Laryngeal Nerve. Dysphagia

15. Grading as per NYHA classification of functional disability: Class I: No symptoms Class II: Symptoms with ordinary activity Class III: Symptoms with less than ordinary activity Class IV: Symptoms at rest.

16. PHYSICAL EXAMINATION Low volume pulse Sign & Symptoms of right sided heart failure - engorged neck veins, enlarged tender liver, pedal edema Atrial fibrillation: irregular pulse and loss of 'a' wave in jugular venous pressure

17. Left parasternal heave : Presence of right ventricular hypertrophy due to pulmonary hypertension Tapping apex beat which is not displaced

18. Mitral Facies Pink purple patches on the cheeks. cyanotic skin changes from low cardiac output. Usually seen in severe MS.

19. ON AUSCULTATION Opening snap Rumbling diastolic murmur best heard at apex radiating to the axilla Loud P2 component of S2: pulmonary hypertension Severity: distance between OS & aortic component of S 2 Closer OS to S 2 more severe the stenosis Calcification of valve: OS disappears

20. LABORATORY INVESTIGATIONS Routine investigations like Hb , TLC, DLC, RFT etc. L.F.T . for assessing hepatic dysfunction d/t RVF A.B.G .-- severe pulmonary symptoms Serum Electrolytes Coagulation profile Chest X-ray- straightening of left heart border, cardiomegaly, double shadow ECG- P mitrale (LAH),Right axis deviation, RVH, AF Echocardiography (TEE)

21. An enlarged left atrium ( white arrow ) which is also seen to be elevating the left main bronchus ( blue arrow ). The blood vessels at the apex are at least as large as those at the base in this upright chest indicating cephalization and elevated pulmonary venous pressure ( white circle )

22. Echocardiography In most cases, the diagnosis of mitral stenosis is most easily made by echocardiography, which shows decreased opening of the mitral valve leaflets , and blunted flow of blood in early diastole. The trans-mitral gradient as measured by doppler echocardiography is the gold standard in the evaluation of the severity of mitral stenosis.

23. Severity of mitral stenosis (Echo)

24. Anaesthetic Management Avoid Tachycardia : Prevent decrease in cardiac output, as hypotension because of this causes reflex tachycardia, which in turn reduces ventricular filling further compromising cardiac output.

25. Avoid Hypotension. Avoid factors precipitating CHF. Avoid precipitation of Right Ventricular Failure Hypercarbia Hypoxemia Lung Hyperinflation Increase in lung water

26. PRE MEDICATION Narcotics, benzodiazepine -- To decrease anxiety & any associated likelihood of adverse circulatory responses produced by tachycardia Anticholinergics - avoided as they increase heart rate Diuretics- Evaluate fluid status , Check electrolytes on day of surgery , Withhold on night before surgery if massive fluid shifts expected in surgery .

27.   Drugs to control AF ( Digoxin, beta blockers, CCB) – Continue in perioperative period Watch serum potassium- in patients receiving digoxin and diuretics Current ACC/AHA guidelines do not recommend endocarditis antibiotic prophylaxis for patients with isolated mitral stenosis undergoing surgical procedures.

28. ANTICOAGULANT THERAPY Management of Patients on warfarin Emergency surgery Discontinue warfarin Give vitamin K 0.5 – 2.0 mg IV FFP 15 ml/kg repeat if necessary Accept for surgery if INR <1.5 Elective surgery Stop 3 days preoperatively monitor INR daily Give heparin when INR <1.5

29. Stop heparin 6 hours prior to surgery Check INR Accept for surgery if INR <1.5 Restart heparin post-operatively as soon as possible

30. Management of Patients on Heparin Emergency surgery Consider reversal with IV protamine 1 mg for every 100 IU of heparin Elective Surgery Stop heparin 6 hours prior to surgery Check INR, accept for surgery if INR <1.5 Restart heparin in post-op as soon as possible If patient is on LMWH, we rarely need to stop it.

31. Induction of Anaesthesia No ideal general anesthetic An opioid is a better choice than a volatile agent for induction. Because volatile agent can produce undesirable vasodilatation, or precipitate junctional rhythm with loss of effective atrial kick. Etomidate best for hemodynamic stabilty

32. Avoid Ketamine – Increases heart rate, blood pressure Avoid Atracurium – Increased histamine release causes hypotension which manifests as tachycardia.

33. Maintenance of Anaesthesia Drugs should have minimal effects on hemodynamic pattern Balanced anaesthesia with N 2 O/ Narcotic/ Volatile anaesthetic N 2 O causes insignificant pulmonary vasoconstriction. It is significant only if pulmonary hypertension exists. So, one needs to treat pulmonary hypertension preoperatively. Cardiac stable muscle relaxants are to be used. (preferably avoid Pancuronium ) Avoid lighter planes of anaesthesia (To avoid tachycardia)

34. Fluid Management: 1) Avoid Hypervolemia --> Worsens pulmonary edema . 2) Avoid Hypovolemia --> Sacrifices already decreased left ventricular filling, which further decreases Cardiac output. Hypovolemia secondary to blood loss and vasodilatory effects of anaesthesia ought to be avoided.

35. Monitoring Transesophageal Echocardiography Intra-arterial pressure Pulmonary artery pressure to be monitored Left atrial pressure A word of caution regarding Pulmonary artery pressure monitoring : - When measured too frequently, the risk of pulmonary artery rupture is far too high.

36. Post Operative Assess postoperative risk of pulmonary oedema and right heart failure and manage accordingly. Avoid pain as pain begets hypoventilation which leads to respiratory acidosis, hypoxemia which manifests as raised heart rate and pulmonary vascular resistance.

37. CONCLUSION Etomidate best for haemodynamic stability. Avoid ketamine and Atracurium . Avoid Tachycardia. Avoid hyper/ hypovolemia Take good care of post op pain.

38. THANK YOU