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Anesthesia for Valvular Heart Surgery Charles E. Smith, MD Professor of Anesthesia Director, Cardiothoracic Anesthesia MetroHealth Medical Center Case.

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Presentation on theme: "Anesthesia for Valvular Heart Surgery Charles E. Smith, MD Professor of Anesthesia Director, Cardiothoracic Anesthesia MetroHealth Medical Center Case."— Presentation transcript:

1 Anesthesia for Valvular Heart Surgery Charles E. Smith, MD Professor of Anesthesia Director, Cardiothoracic Anesthesia MetroHealth Medical Center Case Western Reserve University

2 Objectives Pathophysiology –Aortic valve: AS, AI –Mitral valve: MS, MR –Tricuspid valve: TR Hemodynamic Goals Anesthetic management

3 Aortic Stenosis May occur at 3 levels: 1.Valvular 2.Subvalvular 3.Supravalvular

4 Valvular Aortic Stenosis 1.Calcification + fibrosis of normal tricuspid valve- very common 2.Calcification + fibrosis of congenital bicuspid AV 3.Rheumatic- uncommon since antibiotics

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6 Aortic Stenosis Normal AVA: 2-4 cm 2 Severe AS: AVA < 1cm 2 If normal LV- mean PG > 50 mmHg If poor LV function- mean PG may be low!

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8 Pathophysiology of Aortic Stenosis Chronic LV pressure overload Concentric LVH to wall stress LVH diastolic compliance, coronary blood flow + imbalance of MVO2 supply- demand diastolic compliance LVEDP + LVEDV Myocardial ischemia bc LVH, wall stress, diastolic coronary perfusion + coronary flow reserve

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10 Hemodynamic Goals: AS SR is crucial. Cardiovert SVTs promptly Optimal HR Tachycardia ischemia + ectopy. Bradycardia low CO due to fixed SV Adequate preload essential but difficult to predict bc diastolic dysfunction [TEE useful] Maintain contractility. Avoid myocardial depressants Treat hypotension promptly- phenylephrine, volume, Trendelenburg

11 AS: Considerations Drugs to maintain CPP: –Phenylephrine –Norepinephrine Atrial kick – crucial. HR preferred Spinal + epidural anesthesia poorly tolerated if preload or HR

12 AS: Management Premed: young+ anxious get benzos. Frail + elderly dose (or avoid) Intraop: std monitoring + preinduction art line. Resting HR Avoid myocardial depressants CVP, PAC, TEE- routine for optimal management

13 AS: Weaning from Bypass Thick, hypertrophied heart may be difficult to protect- stone heart still occurs (rare) Noncompliant LV dependent on stable rhythm Inotropes if preop LV dysfunction Dynamic subaortic or cavitary obstruction after AVR if septal LVH Tx w volume, β-blockers. Rarely need myomectomy [inotropes worsen obstruction]

14 Septal LVH with SAM. Tx= volume + beta-blockers

15 Aortic Regurgitation: Etiology 1.Aortic root dilatation- HTN, ascending aorta dissection, cystic medial necrosis, Marfans, syphilitic aortitis, ankylosing spondylitis, osteogenesis imperfecta 2.Deformed + thickened cusps- rheumatic, IE, bicuspid valve 3.Cusp prolapse- dissection

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17 Horse kick to upper chest with severe AI. The RCC was torn from the STJ

18 Pathophysiology: Chronic AR Asymptomatic for many years LV volume + pressure overload occurs LV maintains systolic fct by dilation + compliance LV decompensates at later stages w LVEDP + LVEDV CHF, arrhythmias, sudden death

19 Pathophysiology: Acute AR LV unable to dilate acutely LV volume overload occurs LVEDP + LVEDV acute pulmonary edema Emergency surgery often needed

20 Hemodynamic Goals: AR Optimal HR= 90. Avoid bradycardia- regurg Avoid high afterload SNP preferred Acute AR- often need inotropes + vasodilator [epi+ SNP/milrinone] IABP- contraindicated

21 Anesthetic Management: AR Premed w benzos Routine monitoring: art line, CVP, PAC TEE beneficial Narcotic based technique if impaired LV If acute AR: RSI w ketamine- succinylcholine Inotropes if acute AR or preop LV dysfunction

22 Mitral Stenosis Usually rheumatic- thickening, calcification + fusion of MV leaflets + commissures May be combined w MR + AR Surgery if MVA < 1 cm 2 w NYHA class III or IV dyspnea [or embolus- LAA clot]

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24 MS- Pathophysiology Pressure gradient between LA + LV- prevents LV filling Pulmonary HTN w LAP LAP LAE, atrial arrhythmias (Afib) Pulm HTN RV dysfct, RVE, TR [may need TV repair] LV dysfct uncommon unless CAD

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27 MS: Hemodynamic Goals Preserve SR, if present Avoid tachycardia which diastolic filling of LV + worsens MS Avoid factors which worsen pulmonary HTN- hypercarbia, acidosis, hypothermia, sympathetic nervous system activation, hypoxia

28 Anesthetic Management: MS Premed: benzos to avoid tachycardia If pulm HTN- supplemental O 2 Control of HR- β blockers, digoxin, CEB, amiodarone

29 Intraop Management: MS Std monitors + CVP, PAC, TEE PAP underestimates LVEDP + LVEDV Esmolol: –single most useful drug with severe MS, even if CHF + pulmonary edema –10-20 mg bolus; mcg/kg/min N2O avoided bc effects on pulm HTN Panc avoided bc tachycardia

30 Weaning from Bypass: MS MV replacement- hemodynamics usually improved bc obstruction to LV filling resolved If preop pulm HTN + RV dysfct- may need milrinone or nitric oxide

31 Mitral Regurgitation: Etiology 1.Myxomatous degeneration (most common) 2.Ischemic (functional)- papillary muscle dysfunction, annular dilatation, LV dysfct + tethering 3.Infective endocarditis 4.Trauma

32 Papillary muscle rupture after blunt trauma

33 MR- Pathophysiology Volume overload of LV LVE, LAE LA can massively dilate Atrial arrhythmias with LAE Dilated LV decompensates at later stages w LVEDV

34 Chronic MR. Dilated LA w normal LAP

35 Acute MR. Small LA with LAP+ pulmonary edema

36 Severity of MR 1.Pressure gradient between LA + LV 2.Size of regurgitant orifice (ERO) 3.Duration of ventricular systole

37 Hemodynamic Goals- MR: Vasodilators: NTG, SNP - afterload + regurgitant fraction + forward flow High normal HR to time of ventricular systole Maintain contractility

38 Anesthetic Management MR: MV repair (v. replacement) –preserved papillary muscle + chordae –enhanced LV function –requires TEE to assess repair LV dysfct unmasked after MV surgery bc LV cannot offload into LA May need inotropes + vasodilators

39 Tricuspid Regurgitation Primary: rheumatic, IE, carcinoid, Ebsteins, trauma Secondary: chronic RV dilatation, often w MV disease

40 Flail TV after blunt trauma

41 TR- Pathophysiology RV + RA overloaded + dilated RA v compliant so RAP rises only w end stage disease Pulm HTN due to MV disease- RV afterload + worsens TR RVE paradoxical motion LV septum w imapired LV filling + compliance Right heart failure: hepatomegaly, ascites

42 TR- Hemodynamic Goals If secondary to MV- treat left heart lesion Avoid pulm HTN + high PVR Normal to high preload for RV stroke volume Hypotension treated w inotropes + volume bc vasoconstrictors may worsen pulm HTN

43 TR- Anesthetic Management Premed- benzos Std monitors + art line, CVP, TEE PAC if pulm HTN + MV pathology; but CO overestimated w severe TR. May be impossible to float Swan Weaning from CPB: if preop RV dysfunction/ dilation- inotropes, inodilators, vasodilators, nitric oxide

44 Summary- I Knowledge of patient + extent of valvular heart disease Functional + hemodynamic status Co-morbidities Planned surgery: cannulation sites, repair vs replacement, minimally invasive vs full bypass. Inotropes, vasodilators, vasopressors, infusion pumps

45 Summary- II Understand pathophysiology of lesions + hemodynamic goals: AS, AR, MS, MR, TR Monitoring: standard + invasive +TEE Anesthetic technique: most can be used safely. Adjustment of dosages more important than adhering to a rigid anesthetic technique.


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