Pregnancy with Mitral stenosis

Posted on by Dr.Ajita A
0

☛ RHD is still major problem in india.
☛ Incidence is decresing due to better socioeconomic condition.
☛ MS is mostly associated  with MR , the morbidity is usually related to MS.

Pathophysiology

⤋
MVA 4-6 cm2
⤋
When there is stenosis
⤋
In La presence
⤋
In PAP
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Pul. Congestion
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Pul. Edema
⤋
RV failure

☛ The stenosis develops progressively over the year.
☛ Most patients become symptomatic during mid trimester or in the post-partum period.

Cardiovascular changes in pregnancy

CVS changes

  • Stroke volume ↑ed by 30%.
  • HR ↑ed by  15-25%
  • Cardiac output ↑ed by40-50%
  • O2 consumption ↑es by 30-50%
  • SVR ↓
  • PVR↓
  • Intravascular volume ↑es 45%
  • Diastolic BP ↓
  • Systolic BP minimal or no change.

 

  • All these cardiovascular changes are aqqrevated.
  • In MS, asymptomatic patients tolerate the pregnancy well.
  • The NYHA Gr 3 & 4 th patients have changes of developing pul. Edema & congestive heart failure.
  • Because of increase in metabolic demands and  increase   cardiovascular changes, the pt graded according to NYHA clarification shifts to next class.
  • Severity of MS is graded as follows.
Mild Moderate Severe
MVA 15.5- 2.5 cm2 1-1.5 cm2 < 1 cm2
Pressure gradient < 5 5-15 > 15
PAP < 30 30-50 >50
Symptom NYHA    I Asymptomatic NYHA II –III III- IV

 

Clinical feature   -> HemodynamicS   ->   

 

  • Most patients are asymptomatic.
  • The symptomatypically start when MVA reduces to < 2cm2.
  • At first, the left atrium tries to compensate for it by increasing the left atrial pressure & maintains the cardial output.
  • Gradually as the stenosis worsens, left  atrial pressure ↑es, the pressure gradients across MV ↑es without increasing the cardial output , LA undergoes dilatation.
  • Due to back pressure changes, pulmonary venous HTN occur which is reactive, they transmit it to pulmonary artery & then gradually PAP increses & pulmonary hypertension develops.
  • Because of pulmonary vascular resistance the Rt ventricle undergoes dilatation & ultimately fails.
  • The atrium loses the contractility and goes into atrial fibrillation.
  • Due to atrial fibrillation ,the systolic click is lost and cardial output further falls ,leading to worsening of the condition.
  • The statics of blood in the left atrium leads to thrombus formation and can cause systemic embilisation
  • The risk of maternal death is greatest during labour and during immediate post –partum period, due to auto transfusion from uterus flooding the pulmonary circulation.
  • This auto transfusion continues till 24- 72 use after delivery.
  • Most material deaths occurs in the post – partum period between 2 -9th

 

Diagnosis

  • Clinical Features ➔
  • Fatigue, dypsnea, palpitatious.
  • Generalized weakness, pallor, syncopal attack.
  • Low volume pulse.
  • pulse indicating atrial fibrillation.
  • Mid diastolic Murmur.
  • Opening snap.
  • S3, S4 sound.

 

CxR

  • LA hypertrophy –straightening of heart border .
  • Small aortic knob – due to ↓ed cardiac output.
  • Moustache / Antler sign – prominence of Upper Lobe vessels .
  • Duble atrial shadow.
  • Widening of carinal angle.
  • Calcified MV.
  • Pulmonary hemorrhage.

ECG : P mitrale

  • pulse.
  • Absenceof p wave- AF.

Doppler Echocardiography

  • Area of stenosis
  • Associated lesions
  • HTN .
  • Presense of thronbus.
  • Size of it atrium.
  • Severity of lesions.
  • Wilkins score can be calculated.
  • Role of cardiac catheterization is limited & helpful when clinical & echo findings are not coinciding.

Predication of Mortality

  • Correlates with NYHA class grading.
  • NYHA class III & IV have highest mortality ranging from 5-15 % while class I & II < 1%.

Management

  • According to severity.
  • Grade I
    • Diuretics, o2, bed rest, Beta blockers.
    • Prophylaxis for endocarditis.
    • In presence of AF – Digoxin, Anticoagulation.
  • Grade II: Above management + BMV / CMC/ MVR.
  • Grade III : Surgical repair MVR /balloon valvuloplasty
  • GRADE IV: Above + Antifailure management.

Anticoagulant Guidelines

  • Pts who are in AF require anticoagulants or who had MVR require it.
  • Warfarin causes embrypathy that’s why avoided and given only during 12- 36 Wks of preg.
  • First trimester & 36 Wks onwards -> unFractionated or LMW Heprin.
  • Surgical management is best done is 2nd trimister of pregnancy.
  • Open commissuotony is avoided as it is associated with high risk of fetal loss.
  • Ballon mitral volvotomy is performed & with success rate of 100% without causing mitral regurgitation.
  • In patient’s with calcified valve or severe MS, mitral valve replacement done, but Foetal loss may occour.

Obstetric Management and labour analgesia:

Advantages of labour analgesia

  • Sympathetic of labour analgeria ➔
  • Reduce acidosis
  • Hypocarbia due to hyperventilation
  • Material co – operation.
  • Incordinated interine activity.
  • Can be useful to cut short of 2nd stage of labour by forceps application or vacuum delivery
  • Sudden drop of systemic vascular resistance can be avoided by epidural.
  • Epidural can be extended if caesarian section is required.

Monitoring Required

  • Radial artery annulations
  • cvp monitoring
  • Spo2 monitoring.
  • Metal heart monitoring.
  • O2 supplementation
  • Hypotension – can be treated with insidious volume expansion and small doses of phenylephrine
  • Maintain uterine displacement.

Method Of labour analgesia

  1. Continuous infusions by epidural
  2. PCA
  3. CSE analgesia.

Anesthetic Management For Caesarians Goals

  • Maintain sinus rhythm
  • Avoid tachycardia and bradycardia
  • Maintain SVR avoid precipitous fall
  • Avoid rise in pul vascular resistance.

 

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