A Rare Complication of Aorto-Left Atrial Fistula after Aortic Valve Replacement and its Management with Intraoperative Transoesophageal Echocardiography.

Aorto-atrial fistula is a rare complication of prosthetic aortic valve replacement and most of them have been diagnosed as a late complication. We present a case of this unusual complication after aortic valve replacement which was diagnosed intraoperatively and this potentially disastrous complication was corrected promptly. Early recognition and diagnosis of this rare surgical complication with intraoperative transoesophageal echocardiography (TEE) is imperative for prompt surgical repair of this lethal defect.

INTRODUCTION

Aortic root to left atrium (LA) fistula is a rare complication of prosthetic aortic valve replacement (AVR) and most of them have been diagnosed as a late complication. We present a case of this unusual complication after AVR which was diagnosed intraoperatively using transoesophageal echocardiography (TEE) and this potentially disastrous complication was corrected promptly. The clinical presentation of these fistulae depends on the size of the shunt. They cause a continuous murmur, a thrill, or both.[1]

CASE REPORT

A 71-year-old man presented with complaints of angina. A transthoracic echocardiogram revealed a severe calcific aortic stenosis, mild aortic regurgitation, and normal left ventricular function. Coronary angiogram done showed normal coronaries. An intraoperative TEE confirmed the preoperative findings and patient underwent primary sternotomy with extensive aortic leaflets excision and annular debridement followed by aortic valve replacement with a 21-mm pericardial bioprosthesis.

After separation from cardiopulmonary bypass (CPB), TEE showed an aortic prosthesis was well-seated with a paravalvular leak. However, the jet persisted throughout systole and diastole and did not originate from around the prosthetic sewing ring. A circuitous fistula from an echolucent area surrounding the noncoronary sinus of Valsalva to the LA was successfully traced [Figure 1].

Figure 1

A midesophageal aortic valve long-axis view (ME AV LAX view) showing aortoatrial fistula (arrow) with color-flowDoppler seen traversing the aortic root circuitously and entering the left atrium

The patient was taken back on CPB and the aorto-atrial fistula was closed with a pledgeted suture after opening LA. The patient was separated from CPB smoothly and TEE revealed a small jet remaining [Figure 2], which disappeared completely after subsequent protamine administration [Figure 3].

Figure 2

A postcorrection view showing mild systolic flow in left atrium

Figure 3

A postprotamine view showing no flow in left atrium

DISCUSSION

The complications of fistula formation between the aorta and either atrium are documented after aortic valve endocarditis[23] and aortic dissection.[4] But this complication has been rarely diagnosed in the early postoperative period after valve replacement.[5] Risk factors described include infected tissue before valve replacement, connective tissue abnormalities, extensive aortic annular debridement, and oversized aortic prostheses.[4]

Various case reports of similar complications have described late presentation only of patients lucky enough to survive. There is another case report of similar aortic root to LA fistula complication where it was repaired without going back on CPB.[6]

Intraoperative TEE is proving a useful technique for an early diagnosis of this potentially disastrous complication. Aorto-atrial communications most often originate on the posterior aspect of the aortic annulus adjacent to the left and noncoronary sinuses of Valsalva. TEE allows for imaging of small fistulous tracts because of its close proximity to the aortic root.[5] As a result, discrimination of a fistulous origin from normal coronary blood flow becomes possible.

We describe a rare complication of aortic root to LA fistula after aortic valve replacement diagnosed with intraoperative TEE immediately after separation from CPB. The intraoperative TEE has been proved useful in monitoring for adequacy and complications of valve replacement. Early repeat examination after separation from CPB is essential for diagnosing conditions that may necessitate surgical reexploration such as prosthetic dehiscences, paravalvular leaks, and vascular injury. Ideally, the assessment should be made before administration of protamine, should reinstitution of CPB be required. In this case, repair of the aortic root to LA fistula found required a return to CPB.

COMMENT

Early recognition and diagnosis of the rare surgical complication aorto-LA fistula with intraoperative TEE is imperative for prompt surgical repair of this lethal defect. The aortic root to LA fistula observed here was likely related to difficult and extensive decalcification required during annular debridement.