diff --git a/citations/rezkalla2017.pdf b/citations/rezkalla2017.pdf
new file mode 100644
index 0000000..5ef4f8a
--- /dev/null
+++ b/citations/rezkalla2017.pdf
Binary files differ
diff --git a/drafts/ja/1_introduction.md b/drafts/ja/1_introduction.md
index b016392..d925033 100644
--- a/drafts/ja/1_introduction.md
+++ b/drafts/ja/1_introduction.md
@@ -27,6 +27,8 @@
 末梢保護デバイスは高リスク病変に対しては有効である一方，
 準備に伴う負担からすべての症例に適用することは現実的でなく，
 術前の正確なリスク層別化が不可欠となる．
+また，血管拡張薬の冠動脈内投与には，
+低血圧などの全身性副作用のデメリットもある[rezkalla2017]．
 そこで，PCI手術中に血管壁やプラークの状態を確認できるIVUSに着目した[hibi2013]．
 しかしIVUS画像の読影には専門的な知識を要するうえ，血管径やプラーク組成など複数の因子が複雑に絡み合うため，
 目視のみによる高精度なリスク予測は困難であり，
diff --git a/references.bib b/references.bib
index 9909fcb..27493c7 100644
--- a/references.bib
+++ b/references.bib
@@ -47,6 +47,17 @@
   note    = {In Japanese}
 }
 
+@article{rezkalla2017,
+  author  = {Rezkalla, Shereif H. and Stankowski, Rachel V. and Hanna, Jennifer and Kloner, Robert A.},
+  title   = {Management of No-Reflow Phenomenon in the Catheterization Laboratory},
+  journal = {JACC: Cardiovascular Interventions},
+  year    = {2017},
+  volume  = {10},
+  number  = {3},
+  pages   = {215--223},
+  doi     = {10.1016/j.jcin.2016.11.059}
+}
+
 @article{nishi2021,
   author  = {Nishi, Takeshi and Yamashita, Rikiya and Imura, Shinji and Tateishi, Kazuya and Kitahara, Hideki and Kobayashi, Yoshio and Yock, Paul G. and Fitzgerald, Peter J. and Honda, Yasuhiro},
   title   = {Deep learning-based intravascular ultrasound segmentation for the assessment of coronary artery disease},
diff --git a/sections/1_introduction.tex b/sections/1_introduction.tex
index 85be6f0..13ea814 100644
--- a/sections/1_introduction.tex
+++ b/sections/1_introduction.tex
@@ -35,6 +35,8 @@
 While distal protection devices are effective for high-risk lesions,
 applying them to every case is not realistic given the burden of preparation,
 making accurate pre-procedural risk stratification essential.
+Intracoronary vasodilator administration also carries the drawback of
+systemic side effects such as hypotension \citep{rezkalla2017}.
 We therefore focused on intravascular ultrasound (IVUS),
 which can confirm the condition of the vessel wall and plaque during the PCI
 procedure \citep{hibi2013}.