Mitral Stenosis

Mitral Stenosis • normal MVA 4.0 to 6.0 cm2, Symp(exercise or tachycardia) 2.0 to 2.5 cm2; rest < 1.5 cm2. mild gradient < 5 mm Hg and VA >1.5 cm2. Severe gradient > 10 mmHg, and valve area < 1 cm2. MS in adults is predominantly of rheumatic origin. F>M. • The MV is the most common site of rheumatic valve disease. Long latent period > 20 yrs. Pathogenesis • Obstruction to LV inflow → LA dilation and HTN and resultant pul venous HTN→ interstitial edema→ ↑ work of breathing→ dysponea, and predispose to supraventricular tachyarrythemia. • Pul arteriolar and capillary vasoconstriction protect against pul edema, although ↑ PVR exacerbates pul arterial and RV HTN and causes RVH. • Pul HTN can be severe late in the course of MS, with eventual RV systolic dysfunction. • Acute decompensation occur due to stress e.g. sepsis, pregnancy, A fib, PE→ which can lead to pul edema • Stasis of the blood in the LA→ thrombi→ A fib→ systemic emboli. History • Early fatigue or dyspnea precipitated by events with associated tachycardia, including strenuous physical exercise, emotional stress, fever, pregnancy, or surgery.

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Later, dyspnea occurs with less strenuous activity and eventually at rest, with eventual development of PND and orthopnea that are associated with pul edema and production of frothy, pink sputum. • Patients may note palpitations due to atrial or ventricular ectopic beats, paroxysmal atrial tachycardia, or atrial fib. Dyspnea typically worsens with both sinus tachycardia and with tachyarrhythmias owing to the shortened diastolic interval. • Hemoptysis is a late symptom, caused by rupture of small bronchial vessels in the setting of significant pulmonary hypertension. • Peripheral edema, ascites, and pleural effusion occur late and are caused by right ventricular failure. Physical Findings • malar flushing due to peripheral cyanosis. Neck vein distention occurs caused by RV failure, jugular venous a waves are prominent in patients in sinus rhythm with TR or RV HTN but are absent with A fib, Late signs congestion due to RV failure, with hepatomegaly, ascites, pleural effusion, and peripheral edema. • Pul HTN is associated with the Graham Steell murmur, a blowing diastolic murmur at the right upper sternal border caused by pulmonic insufficiency, and a murmur of TR. Murmurs of aortic or mitral regurgitation or both occur with concomitant valve disease. Laboratory Findings

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ECG: “P mitrale” biphasic P wave, A fib, Pul HTN →RAD, RVH. Mitral Stenosis • CXR: LA and pul venous HTN result in apical redistribution and prominent vascularity in the lung parenchyma, with interstitial edema and peribronchial and perivascular cuffing. Anesthesia management Preload: maintain avoid volume overload and head down Contractility: maintain, avoid myocardial depressant drugs R&R: maintain NSR, avoid tachycardia maintain Afterload: maintain SVR, avoid sudden ↑ in SVR → CHF • In a choice of neuroaxial anesthesia the epidural is better than spinal, because it cause less ↓ in SVR by titrating the LA. • Consider antibiotics prophylactic coverage in a Pt with AS. • Monitors: consider TEE, PAC. • Continue antiarrhythmic drugs peri-op • In case of Pul HTN avoid N2O, consider SNP, NO, prostacyclin • Post-op avoid any stress by optimizing pain control to avoid resp acidosis, hypercarbia, hypoxia, hypothermia which all may ↑ PVR