The resultant stasis and thrombogenic endocardial lesions provide a nidus for thrombus development, placing this group of patients at CLINICAL STATEMENTS AND GUIDELINES risk of stroke. Nonrandomized registry data indi- cate that stroke in the first 3 months after cath- eter ablation is driven chiefly by discontinuation of oral anticoagulation.21 Both US and European guideline statements on catheter ablation rec- ommend (on the basis of expert opinion alone) anticoagulation during this periprocedural phase while the endocardium heals from the ablation. By analogy, patients who have had surgical abla- tion should be managed with at least 3 months of anticoagulation, regardless of their CHA2 - VASc risk score. Subsequent anticoagulation should be based on evaluation of arrhythmia recurrence in the context of their CHA2 -VASc score. Anticoagulation should also be given for at least 3 months after LA ligation/excision. For patients receiving bioprostheses, a VKA would be the preferred method of anticoagulation for the first 3 months (see Section 2.4.3). 5. A higher incidence of early AF in all patients after LA appendage occlusion/exclusion has been dem- Together with the recognition that most patients do not develop AF after surgery, pre- emptive LA appendage occlusion in patients with- out preexisting AF cannot be recommended. No stroke benefit has been observed in this group of patients with no preemptive history of AF. 15. NONCARDIAC SURGERY IN PATIENTS WITH VHD 15.1. Diagnosis of Patients With VHD Undergoing Noncardiac Surgery Recommendation for Diagnosis in Patients With VHD Undergoing Noncardiac Surgery COR LOE Recommendation In patients with clinically suspected moderate or greater degrees of valvular stenosis or regurgitation who are undergoing noncardiac surgery, preoperative echocardiography is recommended. Synopsis The evaluation of patients with VHD who are undergo- ing noncardiac surgery is dependent on the type and Figure 20. Intervention for AF in patients with VHD. 