diff --git a/cartographer/mapping/sparse_pose_graph.cc b/cartographer/mapping/sparse_pose_graph.cc
index 5dbda25..f37ea30 100644
--- a/cartographer/mapping/sparse_pose_graph.cc
+++ b/cartographer/mapping/sparse_pose_graph.cc
@@ -79,7 +79,7 @@ proto::SparsePoseGraph SparsePoseGraph::ToProto() {
     for (size_t old_node_index = 0;
          old_node_index != single_trajectory_nodes.size(); ++old_node_index) {
       const auto& node = single_trajectory_nodes[old_node_index];
-      if (!node.trimmed()) {
+      if (node.constant_data != nullptr) {
         node_id_remapping[NodeId{static_cast<int>(trajectory_id),
                                  static_cast<int>(old_node_index)}] =
             NodeId{static_cast<int>(trajectory_id),
diff --git a/cartographer/mapping/trajectory_node.h b/cartographer/mapping/trajectory_node.h
index 49d3937..dea4d32 100644
--- a/cartographer/mapping/trajectory_node.h
+++ b/cartographer/mapping/trajectory_node.h
@@ -51,7 +51,6 @@ struct TrajectoryNode {
   };
 
   common::Time time() const { return constant_data->time; }
-  bool trimmed() const { return constant_data == nullptr; }
 
   // This must be a shared_ptr. If the data is used for visualization while the
   // node is being trimmed, it must survive until all use finishes.
diff --git a/cartographer/mapping_2d/sparse_pose_graph.cc b/cartographer/mapping_2d/sparse_pose_graph.cc
index ace52f9..9ab257e 100644
--- a/cartographer/mapping_2d/sparse_pose_graph.cc
+++ b/cartographer/mapping_2d/sparse_pose_graph.cc
@@ -202,7 +202,6 @@ void SparsePoseGraph::ComputeConstraintsForOldScans(
   const auto& submap_data = submap_data_.at(submap_id);
   for (const auto& node_id_data : optimization_problem_.node_data()) {
     const mapping::NodeId& node_id = node_id_data.id;
-    CHECK(!trajectory_nodes_.at(node_id).trimmed());
     if (submap_data.node_ids.count(node_id) == 0) {
       ComputeConstraint(node_id, submap_id);
     }
@@ -649,10 +648,10 @@ void SparsePoseGraph::TrimmingHandle::MarkSubmapAsTrimmed(
   parent_->constraint_builder_.DeleteScanMatcher(submap_id);
   parent_->optimization_problem_.TrimSubmap(submap_id);
 
-  // Mark the 'nodes_to_remove' as trimmed and remove their data.
+  // Remove the 'nodes_to_remove' from the sparse pose graph and the
+  // optimization problem.
   for (const mapping::NodeId& node_id : nodes_to_remove) {
-    CHECK(!parent_->trajectory_nodes_.at(node_id).trimmed());
-    parent_->trajectory_nodes_.at(node_id).constant_data.reset();
+    parent_->trajectory_nodes_.Trim(node_id);
     parent_->optimization_problem_.TrimTrajectoryNode(node_id);
   }
 }
diff --git a/cartographer/mapping_3d/sparse_pose_graph.cc b/cartographer/mapping_3d/sparse_pose_graph.cc
index 946ed96..5a1880f 100644
--- a/cartographer/mapping_3d/sparse_pose_graph.cc
+++ b/cartographer/mapping_3d/sparse_pose_graph.cc
@@ -228,7 +228,6 @@ void SparsePoseGraph::ComputeConstraintsForOldScans(
   const auto& submap_data = submap_data_.at(submap_id);
   for (const auto& node_id_data : optimization_problem_.node_data()) {
     const mapping::NodeId& node_id = node_id_data.id;
-    CHECK(!trajectory_nodes_.at(node_id).trimmed());
     if (submap_data.node_ids.count(node_id) == 0) {
       ComputeConstraint(node_id, submap_id);
     }
@@ -676,10 +675,10 @@ void SparsePoseGraph::TrimmingHandle::MarkSubmapAsTrimmed(
   parent_->constraint_builder_.DeleteScanMatcher(submap_id);
   parent_->optimization_problem_.TrimSubmap(submap_id);
 
-  // Mark the 'nodes_to_remove' as trimmed and remove their data.
+  // Remove the 'nodes_to_remove' from the sparse pose graph and the
+  // optimization problem.
   for (const mapping::NodeId& node_id : nodes_to_remove) {
-    CHECK(!parent_->trajectory_nodes_.at(node_id).trimmed());
-    parent_->trajectory_nodes_.at(node_id).constant_data.reset();
+    parent_->trajectory_nodes_.Trim(node_id);
     parent_->optimization_problem_.TrimTrajectoryNode(node_id);
   }
 }