Mitral valve disease – Mitral Regurgitation

1. Mitral valve disease – Mitral Regurgitation Mitral valve fails to close completely, causing blood to flow back into the left atrium during ventricular systole of multiple aetiology www.anaesthesia.co.in anaesthesia.co.in@gmail.com

2. Anatomy of Mitral valve apparatus

3. 45 year old women diagnosed c/o chronic mitral regurgitation posted for abdominal hysterectomy • Natural history • Pathophysiology • Preoperative assessment • Perioperative management

4. Clinical presentation • Depends on Etiology Severity of regurgitation Left ventricular function Pulmonary hypertension Atrial fibrillation Mixed valvular lesion Coronary artery disease & Hypertension

5. Etiopathology • Valve leaflet Rheumatic Carditis Sequlae Myxomatous Degeneration Congenital Cleft Leaflet Marfan Syndrome Infective Endocarditis HOCM Mitral valve prolapse (MVP)

6. Etiopathology • ChordaeTendinae Rheumatic Ischemic • Papillary Muscles Ischemic • Annulus Calcification - elderly patients Dilatation - functional MR

7. Pathophysiology

8. Assessment of severity of MR • Symptoms severity • Presence of PHT • Physical signs of CHF • ECHO

9. Symptoms Depends on Atrial compliance • Normal compliance – pulmonary congestion symptoms Exertionaldyspnea (NYHA ) Orthopnea Right heart failure symptoms ankle edema upper abdominal pain ascites • Increased compliance - low cardiac output symptoms easy fatigue • Palpitations (Atrial fibrillation) • Embolic symptoms or past history

10. Ejection fraction (EF) & MR • Fraction of ventricular end diastolic volume ejected EF = EDV- ESV/EDV • Inspiteof LV dysfunction EF may be normal in range • LA acts as low resistance pathway during systole, EF overestimates LV function • LV dysfunction defined as EF< 60% (AHA Guidelines)

11. Echocardiographic classification of MR

12. Echocardiographic assessment of regurgitant lesions by color – flow Doppler

13. Premedication • Standard doses of any common agents well tolerated & desirable in normal ventricular function • Poor ventricular function – doses proportional to severity of ventricular function • Usual medication on the morning of surgery • Supplemental O2 – PHT or pulmonary disease • Antibiotic prophylaxis ? IE , ? Surgical • Anticoagulation management

14. Monitoring • Depends on LV function & procedure • Full hemodymaic monitoring – if plan for afterload reduction with vasodilators • Color- flow Doppler TEE quantify severity guides therapeutic interventions in severe lesions • Pulmonary artery pressure monitoring

15. Anesthetic management objectives • Tailored to severity of regurgitation jet, LV function • Avoid factors exacerbating the regurgitation Bradycardia - ↑↑ LV end diastolic volume mitral annular dilatation Acute rise in SVR Excess volume expansion – dilates LV Myocardial depression • Prevent & promptly treat AF

16. Hemodynamic goalsMaintain forward systolic flow Full, Fast & Vasodilated

17. Preload • Augment LV preload prior to induction • Remember MR is dynamic • Excess ventricular distension →annular dilatation → worsens MR

18. Heart rate & Rhythm • Bradycardia detrimental ↑duration of systole→ prolongs regurgitation ↑ diastolic filling→ LV distension • Sinus rhythm preferred LV filling less depends on atrial kick as compared to MS

19. Contractility • EF underestimates LV systolic function • Avoid myocardial depression • How to manage hypotension? Manipulate volume & heart rate • Persistent hypotension → inotropic support Dobutamine Low Dose Epinephrine Milrinone

20. Afterload • Low SVR maximizes forward cardiac output Adequate anesthetic depth Systemic vasodilators Inodilators IABP – acute MR • Alpha 1 agonists worsens MR increases SVR & reflex bradycardia • Temporary use of Ephedrine bolus preferable

21. Pulmonary hypertension • PAP & PVR elevated in acute and chronic MR • Secondary RV dysfunction • Avoid factors increasing PVR Hypoxia Hypercapnia Acidosis High tidal volume High PEEP

22. Factors affecting Mitral valve repair • Acute vs chronic MR • Patient’s symptom severity • Left ventricular function • Severity of mitral regurgitation • Feasibility of successessful repair • Combined valvular lesions • Complications of chronic MR

23. Choice of agents • Preserved ventricular function – most anesthetic techniques tolerated well • Spinal, epidural anesthesia tolerated (avoid bradycardia) • Ventricular dysfunction sensitive to volatile agents opioid based anesthetic (avoid bradycardia) pancuronium with opioids useful

24. Symptomatic patients NYHA 2,3 & 4 Indicated • Acute severe MR (class 1) • Absence of severe LV dysfunction(class1) • Severe LV dysfunction & MV repair high likely (2a) • Functional MR ,severe LV dysfunction on maximum medical therapy includes biventricular pacing (2b) (severe LV dysfunction = EF < 30% )

25. Indications for Asymptomatic patients • Chronic severe MR and mild to moderate LV dysfunction (class1) • Chronic sever MR with normal LV function High likely successful repair (2a) New onset atrial fibrillation (2a) Pulmonary hypertension (2a) • Not indicated (class 3) Normal LV function & doubt about feasibility of repair Mild or moderate MR

26. Mitral regurgitation complicating Pregnancy • Typically well tolerated due to favorable loading conditions increased blood volume, heart rate & low SVR • Increased risk of AF ECG monitoring during labor Acute AF – promptly control ventricular rate • Hypercoagulability , increases risk of systemic embolism Anticoagultion New onset AF, H/o embolism & Cardioversion

27. Management of parturient • High SVR during labor – poorly tolerated Pain, Expulsive efforts & aortic compression • Prevent & treat high SVR Epidural analgesia Results in low venous return Left lateral tilt • SAB tolerated by pt’s with mild to moderate MR • Vasopressor of choice Chronotrophic effect of Ephedrine benefits

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