Q. Investigation of aortic regurgitation by Surgical Therapy?
The recommendation for Aortic valve replacement is only for those patients with Severe AR. If patients with mild AR have LV dilatation, dysfunction and symptoms-other causes need to be evaluated and ruled out. If there is uncertainty about the severity of AR-it needs to confirmed with angiographic or any other modality.
In patients with Severe AR with good LV function and symptoms of NYHA Class III-IV or angina Canadian class II or more, surgery is indicated. In patients with NYHA Class II dyspnoea exercise testing is useful. If onset of dyspnoea is recent or patient's LV size and LV
function reach threshold values, i.e., LVEF < 50 per cent or LVEDD about 75 mm or LVESD about 55 mm - surgery is indicated.
AVR is indicated in all symptomatic patients NYHA Class II, III, IV and systolic dysfunction with EF 25 - 49 per cent. In patients with EF < 25 per cent and LVESD more than 60 mm surgery carries high risk. LV dysfunction may be irreversible and post operative morbidity is high. Patients with LV dysfunction do well if the duration of LV dysfunction is short or show improvement with intense vasodilatation, inotropic or diuretic therapy. Clinical judgement should be based on the fact that medical management alone carries very high mortality.
In patients with severe AR and no symptoms, LVEF < 50 per cent, LVEDD > 75 mm or LVESD > 55 mm are indications for surgery. Two consecutive measurements may be obtained in short duration before proceeding with surgery or findings may be confirmed in these asymptomatic patients, by 2 different modalities. AVR is also indicated in patients approaching these LV dimension if they have progressive increase in LV size or any evidence of decreasing exercise tolerance. These dimensions should be tailored to patient's body size but no guidelines are available. Patients with concomitant CAD, Hypertension or other valve disease are also likely to be more symptomatic even with smaller LV size.
Indications for surgery should not be based on the operative techniques used. When aortic root dilatation is equal to or more than 50 mm root reconstruction should accompany aortic valve replacement.
Severity of pre-operative symptoms or reduced exercise tolerance, severity of left ventricular systolic dysfunction and duration of LV dysfunction-all predict post-operative survival and recovery of LV systolic function.