High Output Cardiac Failure Caused by Popliteal Pseudoaneurysm and Arteriovenous Fistula Following Total Knee Replacement Simulating Severe Aortic Stenosis

Abstract

The development of highoutput cardiac failure as a consequence of AVFformation is uncommon but well recognised.Aortic valve disease is relatively common and is awell recognised cause of cardiac failure. The combi-nation of severe aortic stenosis and consequent cardiacfailure is usually an indication for aortic valvereplacement.We describe one case in which high output cardiacfailure due to the formation of a popliteal pseudo-aneurysm and subsequent development of an AVF as acomplication of TKR simulated severe aortic stenosis.We also illustrate the ultrasonographic and angio-graphic findings.Case ReportA 61 year old diabetic, retired computer operatorunderwent a right TKR for osteoarthritis. Six weeksfollowing the surgery he presented to the Accidentand Emergency department with sudden, severeshortness of breath, atrial fibrillation and an ejectionsystolic murmur. His chest X-ray demonstratedpulmonary oedema and appropriate therapy wascommenced, leading to resolution of his cardiacsymptoms.A transthoracic echocardiogram was performedand revealed an instantaneous aortic valve gradientof 65 mmHg and good left ventricular function. As noother cause for his heart failure could be identified, hewas referred for consideration for aortic valve replace-ment and, as part of his work up, underwent coronaryangiography. This showed non-critical coronary arterydisease and a peak to peak aortic valve gradient of30 mmHg. Both the referring cardiologist and thecardiac surgeon, while accepting that the patient hadhaemodynamically significant aortic valve disease,commented that its apparent clinical severity wasgreater than would be expected based on the echo-cardiographic appearance. For this reason, andbecause the patient’s symptoms were well controlled,valve replacement was deferred.Two months later he presented with right footulceration, ischaemic rest pain in his right leg andbreathlessness on minimal exertion equivalent to NewYork Heart Association (NYHA) class 3. His right legwas swollen and a pulsatile mass was palpable behindthe right knee. Ultrasound duplex imaging showed apopliteal aneurysm with an AVF.Fig. 1(a)–(c) shows the popliteal aneurysm and AVFwith high velocity, pulsatile flow through the poplitealartery and vein.Peripheral angiography was subsequentlyperformed.