Mitral Stenosis

Mitral stenosis in pregnancy- pathophysiology & anaesthetic management

1. Mitral Stenosis in Pregnancy: Anesthetic Consideration Dr. Souvik Maitra MD, DNB, EDIC Asst. Prof AIIMS, New Delhi SGPGI- PG ARC- 2019

2. “Mitral stenosis may be concealed under a quarter of a dollar. It is the most difficult of all heart diseases to diagnose.” - Sir William Osler SGPGI- PG ARC- 2019

3. Chief Complains 27y female, G2 P1, village dweller, presented at 39 week of amenorrhea with progressive shortness of breath and palpitation for last 4 months Scheduled for elective LSCS SGPGI- PG ARC- 2019

4. HoPI Shortness of breath- insidious in onset at around 22 wk of amenorrhea, gradually progressing, without any seasonal variation, initially exertional, now patient c/o SOB with ordinary activity. Palpitation- Occasional, increased with activity No h/o hemoptysis No h/o similar illness in the past No history suggestive of acute rheumatic fever in the past SGPGI- PG ARC- 2019

5. Physical Examination Built & nutrition- average BMI 22 BP 100/70, low volume regular pulse, PR 86/min Bi pedal edema + Raised JVP Right parasternal heave + S1- loud, P2- loud Mid- diastolic murmur in the mitral area PA- 38 week of gestation SGPGI- PG ARC- 2019

6. What is the clinical diagnosis? 27y female at 39 week gestation with mitral stenosis with pulmonary hypertension in sinus rhythm. SGPGI- PG ARC- 2019

7. How will you confirm diagnosis? 2D Echocardiography with Doppler Valve area (normal 4-6 cm 2 ) Transvalvular pressure gradient LA dimension PA pressure RV function Presence of LA clot Any other valvular lesion SGPGI- PG ARC- 2019

8. Assessment of severity How mitral stenosis is classified? SGPGI- PG ARC- 2019

9. Clinical staging of MS ACC/ AHA 2014 What are the stages of MS? SGPGI- PG ARC- 2019

10. How to classify dyspnea? NYHA Classification Class I - No symptoms and no limitation in ordinary physical activity, e.g. shortness of breath when walking, climbing stairs etc. Class II - Mild symptoms (mild shortness of breath and/or angina) and slight limitation during ordinary activity. Class III - Marked limitation in activity due to symptoms, even during less-than-ordinary activity, e.g. walking short distances (20- 100 m).Comfortable only at rest. Class IV - Severe limitations. Experiences symptoms even while at rest. Mostly bedbound patients. SGPGI- PG ARC- 2019 SGPGI- PG ARC- 2019

11. Final diagnosis 27y old term pregnant woman at 39 week of gestation with singleton live fetus with severe mitral stenosis (valve area 0.9 cm 2 ), moderate pulmonary hypertension (PA pressure 40 mm Hg) , in sinus rhythm currently NYHA III scheduled for elective LSCS. SGPGI- PG ARC- 2019

12. What are the causes of MS? Rheumatic heart disease LA myxoma Congenital IE with large vegetations SLE, RA Mitral annular calcification ~50% of all rheumatic MS patients don’t have a history of rheumatic fever in childhood. SGPGI- PG ARC- 2019

13. Epidemiology Isolated MS- 40% of all RHD MS with MR- 40% of all RHD Rest 20% are multivalvular lesion Onset of symptoms- 4 th decades of life (in Western countries) Usually 2 nd or 3 rd decades- in India SGPGI- PG ARC- 2019

14. Alteration in CVS examination in pregnancy JVP - Normal/ raised Carotid pulse- Normal volume Peripheral pulse- Well filled Apex beat- Crisp, displaced superiorly, laterally S1- Loud, widely split (early closure of mitral valve) S2- unchanged S3- May be heard RV pulsation may be palpable in thin build women New murmurs are heard in more than 90% of pregnant women SGPGI- PG ARC- 2019

15. Mitral Stenosis: Clinical features Progressive dyspnea Palpitation Fatigue/ syncope Embolism- Stroke/ AMI Hemoptysis Persistent cough Left RLN palsy Edema/ ascites/ hepatomegaly SGPGI- PG ARC- 2019 Ortner Syndrome

16. What are the findings in general survey in patients with MS? Malar flush- ‘mitral facies’ BP- Usually low normal Peripheral pulse- low volume/ irregularly irregular Pedal edema - (?RVF/ ? normal in pregnancy) Build & nutrition- May be under- nurished SGPGI- PG ARC- 2019 Uncommon in Indian patients

17. What are the classic findings in CVS examination: Inspection Raised JVP Visible thrill in the mitral area- may be seen in thin built patients SGPGI- PG ARC- 2019

18. Tapping apex beat Right parasternal heave Palpable P2 Palpable diastolic thrill in mitral area What are the classic findings in CVS examination: Palpation SGPGI- PG ARC- 2019

19. S1- sharp, short & accentuated Low pitched, mid- diastolic rumbling murmur in the mitral area with presystolic accentuation OS- high pitched, just after S2 Loud, narrow split P2 What are the classic findings in CVS examination: Auscultation SGPGI- PG ARC- 2019

20. Why there is pre systolic accentuation? Patients must be on sinus rhythm SGPGI- PG ARC- 2019

21. How the auscultatory findings change with severity? SGPGI- PG ARC- 2019

22. How can you assess disease severity clinically? A2- OS gap- inversely proportional Duration of diastolic murmur Presence of PAH/ RV dysfunction SGPGI- PG ARC- 2019

23. What are the D/D of mid- diastolic murmur? Mitral stenosis Tricuspid stenosis (rarely associated with rheumatic MS) ASD with increased flow across tricuspid valve Ball- valve LA thrombus LA myxoma MR causing increased flow in MV Austin flint murmur SGPGI- PG ARC- 2019

24. What happens to the JVP waves in MS? Large a- wave when RA pressure is elevated Loss of a- wave in AF Large v wave or c-v wave when there is TR SGPGI- PG ARC- 2019

25. What are the typical ECG features in MS? Bifid P wave- ‘P mitrale ’ RAD RVH AF QRS is  POSITIVE  (dominant R wave) in Lead  II , Lead  III  and  aVF QRS is  NEGATIVE  (dominant S wave) in Lead  I 1. RAD 2. Dominant R wave in V 1 3. Dominant S wave in V5/V6 4. QRS duration <120 ms SGPGI- PG ARC- 2019

26. What are the ECG features in Afib ? Irregularly irregular rhythm. No P waves. Absence of an isoelectric baseline. Variable ventricular rate. QRS complexes usually < 120 ms Fibrillatory waves may be present and either fine (amplitude < 0.5mm) or coarse (amplitude >0.5mm). SGPGI- PG ARC- 2019

27. How will assess cardiovascular risk in this patient? SGPGI- PG ARC- 2019

28. What is the WHO classification of maternal cardiac diseases? SGPGI- PG ARC- 2019

29. Anatomy of mitral valve SGPGI- PG ARC- 2019

30. What are the pathological changes in mitral valve? SGPGI- PG ARC- 2019

31. SGPGI- PG ARC- 2019 SGPGI- PG ARC- 2019

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33. What is shape of PV curve in MS? SGPGI- PG ARC- 2019

34. How mitral stenosis is different in pregnancy? SGPGI- PG ARC- 2019

35. What are the cardiovascular change in pregnancy? Cardiac output increases up to 50% Stroke volume increases 20- 30% Heart rate increased by 10- 15% Blood volume increases by 40- 45% SVR decreases throughout pregnancy ~5-10% Mean systemic filling pressure increases SGPGI- PG ARC- 2019

36. Why parturient with MS decompensates? SGPGI- PG ARC- 2019 SGPGI- PG ARC- 2019

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38. MS & pregnancy outcome 67% pregnant women in severe MS develop significant cardiac events IUGR/ IUFD- around 40% untreated cases Pregnant women with MVA<1.5 cm 2 usually become symptomatic- even if they are asymptomatic before pregnancy Usually NYHA status degrades one stage in pregnancy SGPGI- PG ARC- 2019

39. Principles of medical management Anticoagulation Ventricular rate control Maintenance of sinus rhythm Diuresis Bed rest- particularly important in pregnancy SGPGI- PG ARC- 2019

40. Anticoagulation Anticoagulation with VKA in MS with AF (paroxysmal/ persistent/ permanent) LA thrombus Prior embolic/ thrombotic events SGPGI- PG ARC- 2019

41. Anticoagulation in Pregnancy SC/IV heparin for up to 12 weeks antepartum ( aPTT 1.5–2.5-times of normal) Warfarin from 12 to 36 weeks (maintain INR 2.5–3.0) SC/IV heparin after 36 weeks LMWH is preferred over UFH Anti factor X-a level monitoring is recommended in pregnancy SGPGI- PG ARC- 2019

42. How safe are the anticoagulants in pregnancy? Warfarin- Risk of embryopathy, miscarriage & hemorrhage C/I in first & third trimester UFH/ LMWH- does not cross placenta Higher dose of UFH/LMWH required UFH to be discontinued at least 6h before LSCS/ induction of labor LMWH to be discontinued 12h before LSCS/induction of labor Higher plasma volume Higher renal clearance Metabolism by placental heparinase SGPGI- PG ARC- 2019

43. Rate & rhythm control in pregnancy Beta blocker- Metoprolol/ Atenolol- ? Fetal growth restriction Calcium channel blocker- Verapamil may be used Digoxin- unreliable effects in pregnancy SGPGI- PG ARC- 2019

44. Diuretics in pregnancy Furosemide, bumetanide, hydrochlorothiazide- can be used Maternal hypovolemia to be avoided- risk of low cardiac output Oligohydramnios & fetal dys-electrolytemia can occur The BMJ 2018 SGPGI- PG ARC- 2019

45. MS with AF with unstable hemodynamics? Cardioversion is the choice Safe to the fetus at all trimester Transient fetal bradycardia- fetal monitoring required IV heparin- when AF is for more than 48h SGPGI- PG ARC- 2019

46. Intervention in Pregnancy Percutaneous mitral balloon commissurotomy is reasonable for pregnant patients with severe MS (mitral valve area ≤1.5 cm 2 , stage D) with valve morphology favorable , who remain symptomatic with NYHA class III to IV HF symptoms despite medical therapy. Preferably be performed after 20 weeks of gestation Presence of LA thrombus is a contraindication ACC/ AHA 2014 SGPGI- PG ARC- 2019

47. What is favorable valve morphology? A mitral valve with a score <8 to 9 with no more than moderate mitral regurgitation is deemed the best candidate for PBMV. SGPGI- PG ARC- 2019

48. Does surgery have any role? Surgical commissurotomy- Carries high fetal risk (2-10%) MV replacement (CPB)- Risk of fetal loss may be up to 20- 30% Maternal risk 2-8% Patients with severe MS should undergo intervention before pregnancy SGPGI- PG ARC- 2019

49. Obstetric Management SGPGI- PG ARC- 2019

50. Vaginal birth vs LSCS “Vaginal delivery, with epidural analgesia, is preferred for the majority of women. Invasive monitoring should be used in symptomatic women and those with severe MS. ” RCOG 2006 SGPGI- PG ARC- 2019

51. Vaginal birth vs LSCS Mild MS, and in patients with moderate or severe MS in NYHA class I/II without pulmonary hypertension- Vaginal delivery Moderate or severe MS who are in NYHA class III/ IV or have pulmonary hypertension despite medical therapy- LSCS can be considered SGPGI- PG ARC- 2019 ESC 2011

52. Hemodynamics during normal labor SGPGI- PG ARC- 2019

53. Goals during vaginal delivery Second stage of labor to be curtailed Avoid pain & sympathetic stimulation Epidural analgesia is desirable Assisted delivery is the choice SGPGI- PG ARC- 2019

54. Labor analgesia in mitral stenosis Low conc. LA with opioid in epidural IT opioid with low conc. LA in epidural (CSE) can be used IT opioid (fentanyl 25mcg) can be used as sole agent Carefully titrated- avoid sudden vasodilatation Epinephrine test dose- Avoid FHR monitoring is mandatory Goal is to avoid tachycardia & maternal bear down effort Valsalva maneuver Increased venous return Increased CO Increased MV flow Increased LA pressure Increased pulm v. pressure SGPGI- PG ARC- 2019

55. Anesthetic management SGPGI- PG ARC- 2019

56. Preoperative investigations Hemogram Electrolytes (because patients often receive diuretics) 12 lead ECG 2D Echocardiography with Doppler Coagulation profile ( Ptime ?/ aPTT ?) SGPGI- PG ARC- 2019

57. What monitoring will you use? 5-lead ECG SpO2 NIBP IBP EtCO2 CVP? SGPGI- PG ARC- 2019

58. What is the choice of anesthetic technique? General anesthesia, spinal anesthesia, epidural anesthesia & combined spinal epidural anesthesia- all have been used Choice of anesthetic technique depends upon clinical condition of the patients SGPGI- PG ARC- 2019

59. Anesthetic Goals Heart rate- Avoid tachycardia (60- 70 bpm), maintain sinus rhythm Preload- ‘Optimum’ Afterload- Not to be reduced (SBP/ MAP to be maintained within 20% of baseline) Contractility- To be maintained Decrease PVR Hypercarbia Hypoxia Acidosis Mechanical Ventilation SGPGI- PG ARC- 2019

60. What drug to be used for RV failure? Milrinone is the drug of choice Typical dose is 50 mcg/kg loading by IV over 10 minutes, then 0.375-0.75 mcg/kg/min IV  Noradrenaline at low dosage may be needed to counteract hypotension SGPGI- PG ARC- 2019

61. Why tachycardia is detrimental in these patients? Cardiac Output (ml/min) MVA (cm 2 ) = HR (beats/min) x DFP (sec) x 37.7 x HR = heart rate DFP = diastolic filling period   SGPGI- PG ARC- 2019

62. Sub- arachnoid block Single injection SAB not recommended in severe MS- risk of sudden fall in SVR Low dose SAB (1.2ml- 1.5ml) has been used in mild to moderate cases. Boluses of phenylephrine (40- 100 mcg)- for counteracting hypotension & fall in SVR Continuous spinal catheter- option for titration SGPGI- PG ARC- 2019

63. Epidural anesthesia Can be titrated, Slow onset- maternal cardiovascular system may be ‘adapted’ May be associated with less hemodynamic perturbation Larger volume of LA required Can’t be used in emergency scenario SGPGI- PG ARC- 2019

64. Combined spinal- epidural anesthesia Faster onset of block Quality & duration of block can be increased subsequent epidural LA injection. 5- 6 mg 0.5% heavy bupivacaine can be used Epidural supplementation can be provided by 2-3 ml boluses of LA Provides excellent postoperative analgesia Epidural volume expansion by NS can achieve higher block SGPGI- PG ARC- 2019

65. General anesthesia: Indications Patients with ‘critical MS’ Patients with pulmonary edema Patients on LMWH/ UFH Patients who can’t tolerate supine position SGPGI- PG ARC- 2019

66. How will you provide GA in this patient? Induction of general anesthesia Avoid Ketamine- Tachycardia Propofol- Cause decrease in SVR & hypotension Thiopentone- Cause myocardial depression Etomidate- Provides stable maternal hemodynamics Prevent laryngoscopy & intubation responses IV lignocaine IV esmolol IV short acting opioid: Remifentanil (0.5 mg/kg) is choice, fentanyl (1- 2 mcg/kg) can be considered- Neonatology team must be informed SGPGI- PG ARC- 2019

67. Maintenance of anesthesia Nitrous oxide should be avoided if PAH is a concern Potent inhalation anesthetics are choice (isoflurane/ sevoflurane)- Risk of uterine atony Intermediate acting NM blockers are used SGPGI- PG ARC- 2019

68. Reversal of GA Extubation response must be prevented Avoid tachycardia Hypoventilation/ hypoxia to be avoided Post of pain management is of vital management (Postop epidural opioid, TAP block) SGPGI- PG ARC- 2019

69. Fluid & hemodynamics management IV fluid to be optimized- prevent pulmonary edema. Baby delivery causes auto-transfusion of 500- 700 ml of blood Post spinal hypotension to treated by boluses of phenylephrine (25– 100 mcg) Phenylephrine infusion can also be considered (0.75- 2 mcg/kg/min) Avoid beta stimulant drugs (ephedrine/ mephentermine ) SGPGI- PG ARC- 2019

70. How will you guide fluid therapy? CVP- Not a predictor of LA pressure Acute rise of CVP indicates RV dysfunction PCWP is usually overestimates LA pressure PA catheter can derive SV, SVR & PVR SGPGI- PG ARC- 2019