Maintain Full (preload), Slow (heart rate), Constricted (afterload)

Maintain preload – This condition causes the left ventricle (LV) to be chronically under-filled. Maintaining preload is a difficult balance. Too much volume means more pressure on the left atrium (LA) which backs up into the lungs. Too little volume means the LV won’t fill.

Slow-normal Heart Rate – the patient needs to remain on the low side of normal to allow blood to adequately fill the ventricle through the stenotic (narrowed) valve. Increasing the heart rate just overfills the LA and backs up into the lungs- which increases pulmonary edema. Increased heart rate will also put a greater strain on the heart. For this reason, drugs that increase the heart rate should generally be avoided. Tachyarrhythmias can be treated with amiodarone, beta-blockers, calcium channel blockers, digoxin, or cardioversion.

Maintain afterload – A decrease in afterload is going to illicit a baroreceptor reflex – leading to increased heart rate (not good). Treat hypotension with phenylephrine or vasopressin if possible. Ephedrine leads to an increased heart rate (not good).

Support contractility – contractility should be maintained

Avoid PVR – Avoid anything that would increase pulmonary vascular resistance (hypoxia, hypercarbia, and acidosis are the big ones – but also lung hyperinflation, nitrous oxide, trendelenburg position).

AVOID spinals/epidurals – This condition leads to blood stasis in the left atrium so these patients are typically present ANTICOAGULATED to avoid thrombosis formation. If INR < 1.5 it may be considered. If the coagulation profile is permitting, an epidural is recommended over spinal anesthesia to avoid rapid-onset sympathectomy.

Reduction in the opening of the mitral valve (mitral stenosis) causes a backup of blood. This causes increased pressures in the LA and even further back into the lungs. As such, you can expect increased LA pressures, pulmonary artery (PA) pressures, pulmonary capillary wedge pressures (PCWP), pulmonary capillary hydrostatic pressures. This causes pulmonary edema, and if uncorrected, right ventricular failure. Mitral valve opening is normally 4-6 cm2. The disease process is considered severe when the opening has been reduced to 50 mmHg.

Pulmonary artery wedge pressure (PAWP or PAOP) is used to estimate left ventricular pressures. This will be elevated in the presence of mitral stenosis – which is artificially reporting high pressures in the left ventricle.