Valvular Heart Disease

Clinical Orientation

A 78-year-old man with known aortic stenosis has become progressively short of breath walking from his bedroom to the kitchen. He passed out last week while climbing stairs. His echocardiogram shows aortic valve area 0.7 cm2, mean gradient 52 mmHg. The cardiologist says "severe AS." What does that mean for nursing care? This chapter answers: What mechanism links valvular heart disease to bedside findings, tests, red flags, and nursing priorities?

What Goes Wrong?

Stenosis: Valve does not open fully → obstruction to forward flow → pressure overload on the chamber behind it. The chamber hypertrophies to generate higher pressure. Eventually, hypertrophy outpaces blood supply → ischemia, fibrosis, failure.

Regurgitation: Valve does not close fully → backward leak → volume overload on BOTH the chamber behind and the chamber ahead. The chamber dilates to accommodate the extra volume. Eventually, dilation → wall stress increase → failure.

Aortic stenosis — the classic triad: Angina (LVH + increased O2 demand + decreased coronary flow reserve), Syncope (inability to increase CO with exertion + possible arrhythmia), Heart failure (pump failure). The onset of symptoms marks a dramatic worsening of prognosis — AS becomes a surgical disease.

Mitral regurgitation: Acute MR (papillary muscle rupture post-MI) → sudden LA volume overload → flash pulmonary edema. Chronic MR → gradual LA enlargement → tolerated for years, but eventually LV fails.

What the Nurse May See

Aortic stenosis: Slow-rising, diminished carotid pulse (pulsus parvus et tardus). Narrow pulse pressure. Harsh systolic ejection murmur at right upper sternal border radiating to carotids. S4 (stiff LV from hypertrophy). Syncope with exertion. Angina. Late: heart failure signs.

Mitral regurgitation: Holosystolic murmur at apex radiating to axilla. S3 (volume overload). Atrial fibrillation common. Chronic: fatigue, dyspnea on exertion. Acute: sudden pulmonary edema.

Prosthetic valves: Mechanical valves require lifelong anticoagulation (warfarin, INR target 2.5-3.5 depending on valve position and type). Audible mechanical click — absence suggests thrombosis. Bioprosthetic valves may not require long-term anticoagulation.

Nursing Priorities

1. Monitor for decompensation: New or worsening murmur, new dyspnea, syncope, angina, heart failure signs.
2. Afterload management: For aortic stenosis, avoid vasodilation that drops afterload — the stenotic valve is the fixed resistance, and coronary perfusion depends on adequate aortic diastolic pressure. Hypotension is poorly tolerated.
3. Anticoagulation for mechanical valves: Strict INR monitoring. Patient education about bleeding risk, drug interactions, dietary vitamin K consistency.
4. Endocarditis prophylaxis: Current guidelines recommend prophylaxis only for high-risk patients (prosthetic valves, prior endocarditis, certain congenital heart disease, cardiac transplant with valve disease) before dental procedures involving gingival manipulation.

Red Flags