diff --git a/torch_geometric/utils/rag/backend_utils.py b/torch_geometric/utils/rag/backend_utils.py
index bcb15fcd4b34..be5f41d998a7 100644
--- a/torch_geometric/utils/rag/backend_utils.py
+++ b/torch_geometric/utils/rag/backend_utils.py
@@ -244,13 +244,12 @@ def make_pcst_filter(triples: List[Tuple[str, str, str]],
                      model: SentenceTransformer):
     if DataFrame is None:
         raise Exception("PCST requires `pip install pandas`")
-    all_nodes = []
-    for triple in triples:
-        if triple[0] in all_nodes:
-            all_nodes.append(triple[0])
-        if triple[2] in all_nodes:
-            all_nodes.append(triple[2])
-    full_textual_nodes = all_nodes
+    nodes = []
+    for h, r, t in triples:
+        for node in (h, t):
+            if node not in nodes:
+                nodes.append(node)
+    full_textual_nodes = nodes
 
     def apply_retrieval_via_pcst(
         graph: Data,