This copy is for personal use only. To order printed copies, contact [email protected] LETTERS TO THE EDITOR
3. Hallynck TH, Soep HH, Thomis JA, Boelaert J, Daneels R, Dettli L. Should clearance be normalised to body surface or to lean body mass? Br J Clin Pharmacol 1981;11(5):523– 526. 4. Statistics Sweden. www.scb.se. Published online October 3, 2012. Accessed December 2, 2015. 5. Boer P. Estimated lean body mass as an index for normalization of body fluid volumes in humans. Am J Physiol 1984;247(4):F632– F636.
Response From Kazuo Awai, MD, PhD,* and Yasuyuki Yamashita, MD, PhD† Department of Diagnostic Radiology, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, 7348551 Hiroshima, Japan* e-mail: [email protected] Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan† We thank Dr Nyman for his comments about our study (1). The James formula (2) is commonly used for calculating the contrast material dose for CT (3–5). It is also incorporated into many modern positron emission tomography/CT systems to calculate the standardized uptake value based on the LBW (6). We fully agree with Dr Nyman that the James formula is not necessarily appropriate in patients with a high BMI and that the Boer formula is more appropriate in such patients. In our study, the mean BMI for women and men was 22.2 kg/m2 (range, 13.2–36.7 kg/m2) and 22.4 kg/m2 (range, 12.1–42.0 kg/m2), respectively. In this population, there is a very strong linear correlation between the estimated LBW calculated with the James formula and the estimated LBW obtained with the Boer formula. The correlation coefficient was 0.981 (95% confidence interval: 0.979, 0.983), and the mean difference in the estimated LBW calculated with the two methods was 0.127 kg (range, −6.88 to 4.65 kg). Therefore, almost the same results are obtained with the Boer and the James formula.
The Janmahasatian formula (7) is another formula for estimating the LBW; it can be applied in patients with a high BMI. As it involves an increasing function of weight and plateaus at large weight values, it can be applied in a wide range of body weights. Studies are needed to assess whether the Boer or the Janmahasatian formula is better for estimating the LBW for the determination of the appropriate contrast material dose. Disclosures of Conflicts of Interest: K.A. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: received a research grant from Bayer Yakuhin, Daiichi-Sankyo, Eizai, and Toshiba Medical Systems. Other relationships: disclosed no relevant relationships. Y.Y. disclosed no relevant relationships.
References 1. Awai K, Kanematsu M, Kim T, et al. The optimal body size index with which to determine iodine dose for hepatic dynamic CT: a prospective multicenter study. Radiology doi: 10.1148/radiol.2015142941. Published online September 10, 2015. 2. James WPT. Research on obesity: a report of the DHSS/MRC group. London, England: Her Majesty’s Stationery Office, 1976. 3. Ho LM, Nelson RC, Delong DM. Determining contrast medium dose and rate on basis of lean body weight: does this strategy improve patient-to-patient uniformity of hepatic enhancement during multi–detector row CT? Radiology 2007;243(2):431–437. 4. Kidoh M, Nakaura T, Oda S, et al. Contrast enhancement during hepatic computed tomography: effect of total body weight, height, body mass index, blood volume, lean body weight, and body surface area. J Comput Assist Tomogr 2013;37(2):159–164. 5. Kondo H, Kanematsu M, Goshima S, et al. Body size indexes for optimizing iodine dose for aortic and hepatic enhancement at multidetector CT: comparison of total body weight, lean body weight, and blood volume. Radiology 2010;254(1):163–169. 6. Tahari AK, Chien D, Azadi JR, Wahl RL. Optimum lean body formulation for correction of standardized uptake value in PET imaging. J Nucl Med 2014;55(9):1481–1484. 7. Janmahasatian S, Duffull SB, Ash S, Ward LC, Byrne NM, Green B. Quantification of lean bodyweight. Clin Pharmacokinet 2005;44(10):1051–1065.
Radiology: Volume 278: Number 3—March 2016 n radiology.rsna.org
Severe Bleeding after Percutaneous Transhepatic Drainage of the Biliary System From Tin Htun Aung, MMedSc (Radiology), Chow Wei Too, FRCR, Nanda Kumar, FRCR, Karthikeyan Damodharan, FRCR, Thijs August Urlings, FRCR, Ankur Patel, FRCR, Shaun Chan, FRCR, Luke Toh, FRCR, Apoorva Gogna, FRCR, Farah Irani, FRCR, Richard Lo, FRCR, Bien Soo Tan, FRCR, Kiang Hiong Tay, FRCR, and Leong Sum, FFRRCSI Department of Diagnostic Radiology, Singapore General Hospital, Outram Rd, Singapore 169608 e-mail: [email protected]
Editor: We read with interest the article by Dr Hamada and colleagues in the February 2015 issue of Radiology (1) regarding the effect of antithrombotic agents on severe bleeding after percutaneous transhepatic biliary drainage (PTBD). This is a timely review of an important subject, and we congratulate the authors on such a frank and thorough study. New PTBD catheter insertion has a significant bleeding risk, which can be difficult to detect or control, according to Society of Interventional Radiology guidelines (2). Dr Hamada and colleagues reviewed the association between oral administration of antithrombotic agents before PTBD and severe bleeding in a large 4-year nationwide administrative database. They found that the continuation of antiplatelet agents can increase severe bleeding after PTBD, concluding that the management of antiplatelet agents in the periprocedural period deserves further investigation, balancing reduction in bleeding risk and increased vascular events arising from drug discontinuation. Apart from the discontinuation of the antiplatelet agent, which can be difficult in cases such as postcoronary artery drug-eluting stent placement, the use of intraprocedural platelet 957
LETTERS TO THE EDITOR
transfusion could be considered (3). Although blood product transfusion may carry some risks (4), it may not be possible to delay PTBD insertion for up to 5 days as suggested by Society of Interventional Radiology guidelines, as overwhelming biliary sepsis may be fatal (5). Patients with uremia, who have platelet dysfunction, may benefit from desmopressin administration (6), including those who are also taking antiplatelet therapy (7). Given as a single infusion, it is usually well tolerated with improved objective measure of platelet dysfunction (7). Finally, another explanation for inconclusive findings on anticoagulation effects is that therapeutic range for warfarin therapy is only achieved in 57%–66% of cases in the population (8); thus, estimation of bleeding risk and requirement of periprocedural vitamin K or fresh-frozen plasma administration should be made with clotting time information. Once again, we congratulate the authors on the publication of a timely and important study. Disclosures of Conflicts of Interest: T.H.T. disclosed no relevant relationships. C.W.T. disclosed no relevant relationships. N.K. disclosed no relevant relationships. K.D. disclosed no relevant relationships. T.A.U. disclosed no relevant relationships. A.P. disclosed no relevant relationships. S.C. disclosed no relevant relationships. L.T. disclosed no relevant relationships. A.G. disclosed no relevant relationships. F.I. disclosed no relevant relationships. R.L. disclosed no relevant relationships. B.S.T. disclosed no relevant relationships. K.H.T. disclosed no relevant relationships. L.S. disclosed no relevant relationships.
References 1. Hamada T, Yasunaga H, Nakai Y, et al. Severe bleeding after percutaneous transhepatic drainage of the biliary system: effect of antithrombotic agents—analysis of 34 606 cases from a Japanese nationwide administrative database. Radiology 2015;274(2):605–614. 2. Patel IJ, Davidson JC, Nikolic B, et al. Consensus guidelines for periprocedural management of coagulation status and hemostasis risk in percutaneous image-guided interventions. J Vasc Interv Radiol 2012;23(6)727– 736. 3. Scharf RE. Management of bleeding in pa tients using antithrombotic agents: prediction, prevention, protection and problem-
958
oriented intervention. Hamostaseologic 2009; 29(4):388–398. 4. Blumberg N, Heal JM, Gordon L Phillips GL. Platelet transfusions: trigger, dose, benefits, and risks. F1000 Med Rep 2010;2:5. 5. Wada K, Takada T, Kawarada Y, et al. Diagnostic criteria and severity assessment of acute cholangitis: Tokyo guidelines. J Hepatobiliary Pancreat Surg 2007 Jan; 14(1): 52–58. 6. Radhakrishnan S, Chanchlani R, Connolly B, Langlois V. Pre-procedure desmopressin acetate to reduce bleeding in renal failure: does it really work? Nephron Clin Pract 2014; 128(1-2):45–48. 7. Kim JH, Baek CH, Min JY, Kim JS, Kim SB, Kim H. Desmopressin improves platelet function in uremic patients taking antiplatelet agents who require emergent invasive procedures. Ann Hematol 2015;94(9):1457–1461. 8. van Walraven C, Jennings A, Oake N, Fergusson D, Forster AJ. Effect of study setting on anticoagulation control: a systematic review and metaregression. Chest 2006;129:1155– 1166.
Response From Tsuyoshi Hamada, MD, PhD,* Hideo Yasunaga, MD, PhD,† Yousuke Nakai, MD, PhD,* Hiroyuki Isayama, MD, PhD,* and Kazuhiko Koike, MD, PhD* Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan* e-mail: [email protected] Department of Clinical Epidemiology and Health Economics, School of Public Health, University of Tokyo, Tokyo, Japan† We appreciate the comments by Dr Aung and colleagues about our recent article (1). Their legitimate concerns about antithrombotic agent users receiving percutaneous drainage of the biliary system clearly implicate clinical questions to be addressed in future studies. In cases where the discontinuation of antiplatelet agents is unacceptable or insufficient, potential measures to prevent severe procedure-related bleeding should be considered. Platelet transfusion is a reasonable procedure that
can restore impaired platelet function, although it is not commonly used in Japan. Theoretically, however, rapid platelet activation might provoke vascular events as with drug discontinuation. Therefore, as often discussed about red cell transfusion (2), the threshold of platelet level and the dose of platelet transfusion should be discussed. Moreover, other specific strategies, for example, desmopressin for patients with chronic renal failure, should be taken into account (3), but a large sample size is required to determine the effectiveness of those countermeasures for a small subset of patients. Endoscopic drainage is less susceptible to bleeding compared with percutaneous drainage and, hence, can be a treatment option for patients at high risk for bleeding (4,5), which is estimated based on risk factors identified in our study. Clinical evaluation of anticoagulant users in the periprocedural period is considerably complicated owing to various confounding factors—for example, warfarin reversal by means of vitamin K, heparin bridging therapy, and freshfrozen plasma administration. In the Society of Interventional Radiology consensus guidelines (3), the international normalized ratio of prothrombin time should be corrected to less than 1.5 in the periprocedural period of both percutaneous biliary drainage and cholecystostomy. As Dr Aung and colleagues advocated, the level of prothrombin time should be considered to treat patients on anticoagulants; unfortunately, however, it was unavailable in the inpatient database used in our study (1). Meanwhile, the management of novel oral anticoagulants (eg, dabigatran, rivaroxaban) deserves an urgent investigation (6). Finally, nationwide multicenter collaboration of interventional radiologists is required to prospectively examine the appropriate management of antithrombotic agents in various specific settings. Disclosures of Conflicts of Interest: T.H. Activities related to the present article: received grants from the Japanese government. Activities not related to the present article: disclosed no relevant relationships. Other relationships: disclosed no relevant relationships. H.Y. Activities related to the present article: received grants
radiology.rsna.org n Radiology: Volume 278: Number 3—March 2016
LETTERS TO THE EDITOR
from the Japanese government. Activities not related to the present article: disclosed no relevant relationships. Other relationships: disclosed no relevant relationships. Y.N. Activities related to the present article: received grants from the Japanese government. Activities not related to the present article: disclosed no relevant relationships. Other relationships: disclosed no relevant relationships. H.I. Activities related to the present article: received grants from the Japanese government. Activities not related to the present article: disclosed no relevant relationships. Other relationships: disclosed no relevant relationships. K.K. Activities related to the present article: received grants from the Japanese government. Activities not related to the present article: disclosed no relevant relationships. Other relationships: disclosed no relevant relationships.
References 1. Hamada T, Yasunaga H, Nakai Y, et al. Severe bleeding after percutaneous transhepatic drainage of the biliary system: effect of antithrombotic agents—analysis of 34 606 cases from a Japanese nationwide administrative database. Radiology 2015;274(2):605–613. 2. Villanueva C, Colomo A, Bosch A, et al. Transfusion strategies for acute upper gastrointestinal bleeding. N Engl J Med 2013;368(1):11–21. 3. Patel IJ, Davidson JC, Nikolic B, et al. Consensus guidelines for periprocedural management of coagulation status and hemostasis risk in percutaneous image-guided interventions. J Vasc Interv Radiol 2012;23(6):727–736. 4. Sharma BC, Kumar R, Agarwal N, Sarin SK. Endoscopic biliary drainage by nasobiliary drain or by stent placement in patients with acute cholangitis. Endoscopy 2005;37(5):439– 443. 5. Itoi T, Kawakami H, Katanuma A, et al. Endoscopic nasogallbladder tube or stent placement in acute cholecystitis: a preliminary prospective randomized trial in Japan (with videos). Gastrointest Endosc 2015;81(1):111–118. 6. Baron TH, Kamath PS, McBane RD. Man agement of antithrombotic therapy in patients undergoing invasive procedures. N Engl J Med 2013;368(22):2113–2124.
Role of Coronary CT Angiography in Patients with Stroke From Kemal Kara, MD, Ersin Ozturk, MD, and Onur Sildiroglu, MD Department of Radiology, GATA Haydarpasa Teaching Hospital, Uskudar, Istanbul, Turkey e-mail: [email protected]
Editor: We read with interest the article by Dr Lee and colleagues in the August 2015 issue of Radiology titled “Predictors of Recurrent Stroke in Patients with Ischemic Stroke: Comparison Study between Transesophageal Echocardiography and Cardiac CT" (1). The authors evaluated the value of cardiac computed tomography (CT) and compared cardiac CT findings with those from transesophageal echocardiography in patients with ischemic stroke. We would like to share our coronary CT angiography experience with frequently detected abnormalities related to stroke. In the study by Dr Lee and colleagues, the cause of cardiogenic emboli was classified into seven different groups. However, atrial diverticulum may be another etiologic factor and was not mentioned (1). Atrial diverticulum has an important role in the cause and prevalence of thromboembolism and atrial fibrillation (2). In a coronary CT angiography study, the incidence of atrial diverticulum has been reported as 41%, and this ratio is more than the incidence of patent foramen ovale (PFO), which was reported to be 24.9% (3). Valvular vegetation is frequently associated with atrial tachycardia. It is not appropriate to evaluate the images in tachycardia or atrial fibrillation without using a beta-blocker (4). Dr Lee and colleagues stated that they did not use a beta-blocker in their study; however, vegetation could be easily missed in such cases. In addition, the detection of vegetation smaller than 4 mm is very difficult with coronary CT angiography (5). The size of the vegetation should be mentioned as a limitation in the study by Dr Lee and colleagues (1). The importance of a PFO in ischemic stroke was mentioned, but the septal pouch (probe PFO) concept was not emphasized. However, the blood stasis in the septal pouch is included as a new entity in the origin of thromboembolism (6). In conclusion, stroke is a major cause of mortality and morbidity and coronary CT angiography is a highly effective and reliable imaging method for
Radiology: Volume 278: Number 3—March 2016 n radiology.rsna.org
detecting the underlying cardiac cause of stroke. Disclosures of Conflicts of Interest: K.K. disclosed no relevant relationships. E.O. disclosed no relevant relationships. O.S. disclosed no relevant relationships.
References 1. Lee K, Hur J, Hong SR, et al. Predictors of recurrent stroke in patients with ischemic stroke: comparison study between transesophageal echocardiography and cardiac CT. Radiology 2015;276(2):381–389. 2. Balli O, Aytemir K, Karcaaltincaba M. Multidetector CT of left atrium. Eur J Radiol 2012;81(1):e37–e46. 3. Incedayi M, Öztürk E, Sonmez G, et al. The incidence of left atrial diverticula in coronary CT angiography. Diagn Interv Radiol 2012; 18(6):542–546. 4. Entrikin DW, Gupta P, Kon ND, Carr JJ. Imaging of infective endocarditis with cardiac CT angiography. J Cardiovasc Comput Tomogr 2012;6(6):399–405. 5. Feuchtner GM, Stolzmann P, Dichtl W, et al. Multislice computed tomography in infective endocarditis:comparison with transesophageal echocardiography and intraoperative findings. J Am Coll Cardiol 2009;53(5):436–444. 6. Krishnan SC, Salazar M. Septal pouch in the left atrium: a new anatomical entity with potential for embolic complications. JACC Cardiovasc Interv 2010;3(1):98–104.
Response From Jin Hur, MD, PhD,* Kyeho Lee, MD,† and Byoung Wook Choi, MD, PhD* Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, 120-752, Seoul, Republic of Korea* e-mail: [email protected] Department of Radiology, Dankook University Hospital, Cheonan city, Chungnam Province, Republic of Korea† We appreciate Dr Kara and colleagues’ interest in our recent work. They have suggested that left atrial septal pouch (LASP) could be another etiologic factor for cardioembolic stroke not mentioned in our recent study (1). 959
3. Hallynck TH, Soep HH, Thomis JA, Boelaert J, Daneels R, Dettli L. Should clearance be normalised to body surface or to lean body mass? Br J Clin Pharmacol 1981;11(5):523– 526. 4. Statistics Sweden. www.scb.se. Published online October 3, 2012. Accessed December 2, 2015. 5. Boer P. Estimated lean body mass as an index for normalization of body fluid volumes in humans. Am J Physiol 1984;247(4):F632– F636.
Response From Kazuo Awai, MD, PhD,* and Yasuyuki Yamashita, MD, PhD† Department of Diagnostic Radiology, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, 7348551 Hiroshima, Japan* e-mail: [email protected] Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan† We thank Dr Nyman for his comments about our study (1). The James formula (2) is commonly used for calculating the contrast material dose for CT (3–5). It is also incorporated into many modern positron emission tomography/CT systems to calculate the standardized uptake value based on the LBW (6). We fully agree with Dr Nyman that the James formula is not necessarily appropriate in patients with a high BMI and that the Boer formula is more appropriate in such patients. In our study, the mean BMI for women and men was 22.2 kg/m2 (range, 13.2–36.7 kg/m2) and 22.4 kg/m2 (range, 12.1–42.0 kg/m2), respectively. In this population, there is a very strong linear correlation between the estimated LBW calculated with the James formula and the estimated LBW obtained with the Boer formula. The correlation coefficient was 0.981 (95% confidence interval: 0.979, 0.983), and the mean difference in the estimated LBW calculated with the two methods was 0.127 kg (range, −6.88 to 4.65 kg). Therefore, almost the same results are obtained with the Boer and the James formula.
The Janmahasatian formula (7) is another formula for estimating the LBW; it can be applied in patients with a high BMI. As it involves an increasing function of weight and plateaus at large weight values, it can be applied in a wide range of body weights. Studies are needed to assess whether the Boer or the Janmahasatian formula is better for estimating the LBW for the determination of the appropriate contrast material dose. Disclosures of Conflicts of Interest: K.A. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: received a research grant from Bayer Yakuhin, Daiichi-Sankyo, Eizai, and Toshiba Medical Systems. Other relationships: disclosed no relevant relationships. Y.Y. disclosed no relevant relationships.
References 1. Awai K, Kanematsu M, Kim T, et al. The optimal body size index with which to determine iodine dose for hepatic dynamic CT: a prospective multicenter study. Radiology doi: 10.1148/radiol.2015142941. Published online September 10, 2015. 2. James WPT. Research on obesity: a report of the DHSS/MRC group. London, England: Her Majesty’s Stationery Office, 1976. 3. Ho LM, Nelson RC, Delong DM. Determining contrast medium dose and rate on basis of lean body weight: does this strategy improve patient-to-patient uniformity of hepatic enhancement during multi–detector row CT? Radiology 2007;243(2):431–437. 4. Kidoh M, Nakaura T, Oda S, et al. Contrast enhancement during hepatic computed tomography: effect of total body weight, height, body mass index, blood volume, lean body weight, and body surface area. J Comput Assist Tomogr 2013;37(2):159–164. 5. Kondo H, Kanematsu M, Goshima S, et al. Body size indexes for optimizing iodine dose for aortic and hepatic enhancement at multidetector CT: comparison of total body weight, lean body weight, and blood volume. Radiology 2010;254(1):163–169. 6. Tahari AK, Chien D, Azadi JR, Wahl RL. Optimum lean body formulation for correction of standardized uptake value in PET imaging. J Nucl Med 2014;55(9):1481–1484. 7. Janmahasatian S, Duffull SB, Ash S, Ward LC, Byrne NM, Green B. Quantification of lean bodyweight. Clin Pharmacokinet 2005;44(10):1051–1065.
Radiology: Volume 278: Number 3—March 2016 n radiology.rsna.org
Severe Bleeding after Percutaneous Transhepatic Drainage of the Biliary System From Tin Htun Aung, MMedSc (Radiology), Chow Wei Too, FRCR, Nanda Kumar, FRCR, Karthikeyan Damodharan, FRCR, Thijs August Urlings, FRCR, Ankur Patel, FRCR, Shaun Chan, FRCR, Luke Toh, FRCR, Apoorva Gogna, FRCR, Farah Irani, FRCR, Richard Lo, FRCR, Bien Soo Tan, FRCR, Kiang Hiong Tay, FRCR, and Leong Sum, FFRRCSI Department of Diagnostic Radiology, Singapore General Hospital, Outram Rd, Singapore 169608 e-mail: [email protected]
Editor: We read with interest the article by Dr Hamada and colleagues in the February 2015 issue of Radiology (1) regarding the effect of antithrombotic agents on severe bleeding after percutaneous transhepatic biliary drainage (PTBD). This is a timely review of an important subject, and we congratulate the authors on such a frank and thorough study. New PTBD catheter insertion has a significant bleeding risk, which can be difficult to detect or control, according to Society of Interventional Radiology guidelines (2). Dr Hamada and colleagues reviewed the association between oral administration of antithrombotic agents before PTBD and severe bleeding in a large 4-year nationwide administrative database. They found that the continuation of antiplatelet agents can increase severe bleeding after PTBD, concluding that the management of antiplatelet agents in the periprocedural period deserves further investigation, balancing reduction in bleeding risk and increased vascular events arising from drug discontinuation. Apart from the discontinuation of the antiplatelet agent, which can be difficult in cases such as postcoronary artery drug-eluting stent placement, the use of intraprocedural platelet 957
LETTERS TO THE EDITOR
transfusion could be considered (3). Although blood product transfusion may carry some risks (4), it may not be possible to delay PTBD insertion for up to 5 days as suggested by Society of Interventional Radiology guidelines, as overwhelming biliary sepsis may be fatal (5). Patients with uremia, who have platelet dysfunction, may benefit from desmopressin administration (6), including those who are also taking antiplatelet therapy (7). Given as a single infusion, it is usually well tolerated with improved objective measure of platelet dysfunction (7). Finally, another explanation for inconclusive findings on anticoagulation effects is that therapeutic range for warfarin therapy is only achieved in 57%–66% of cases in the population (8); thus, estimation of bleeding risk and requirement of periprocedural vitamin K or fresh-frozen plasma administration should be made with clotting time information. Once again, we congratulate the authors on the publication of a timely and important study. Disclosures of Conflicts of Interest: T.H.T. disclosed no relevant relationships. C.W.T. disclosed no relevant relationships. N.K. disclosed no relevant relationships. K.D. disclosed no relevant relationships. T.A.U. disclosed no relevant relationships. A.P. disclosed no relevant relationships. S.C. disclosed no relevant relationships. L.T. disclosed no relevant relationships. A.G. disclosed no relevant relationships. F.I. disclosed no relevant relationships. R.L. disclosed no relevant relationships. B.S.T. disclosed no relevant relationships. K.H.T. disclosed no relevant relationships. L.S. disclosed no relevant relationships.
References 1. Hamada T, Yasunaga H, Nakai Y, et al. Severe bleeding after percutaneous transhepatic drainage of the biliary system: effect of antithrombotic agents—analysis of 34 606 cases from a Japanese nationwide administrative database. Radiology 2015;274(2):605–614. 2. Patel IJ, Davidson JC, Nikolic B, et al. Consensus guidelines for periprocedural management of coagulation status and hemostasis risk in percutaneous image-guided interventions. J Vasc Interv Radiol 2012;23(6)727– 736. 3. Scharf RE. Management of bleeding in pa tients using antithrombotic agents: prediction, prevention, protection and problem-
958
oriented intervention. Hamostaseologic 2009; 29(4):388–398. 4. Blumberg N, Heal JM, Gordon L Phillips GL. Platelet transfusions: trigger, dose, benefits, and risks. F1000 Med Rep 2010;2:5. 5. Wada K, Takada T, Kawarada Y, et al. Diagnostic criteria and severity assessment of acute cholangitis: Tokyo guidelines. J Hepatobiliary Pancreat Surg 2007 Jan; 14(1): 52–58. 6. Radhakrishnan S, Chanchlani R, Connolly B, Langlois V. Pre-procedure desmopressin acetate to reduce bleeding in renal failure: does it really work? Nephron Clin Pract 2014; 128(1-2):45–48. 7. Kim JH, Baek CH, Min JY, Kim JS, Kim SB, Kim H. Desmopressin improves platelet function in uremic patients taking antiplatelet agents who require emergent invasive procedures. Ann Hematol 2015;94(9):1457–1461. 8. van Walraven C, Jennings A, Oake N, Fergusson D, Forster AJ. Effect of study setting on anticoagulation control: a systematic review and metaregression. Chest 2006;129:1155– 1166.
Response From Tsuyoshi Hamada, MD, PhD,* Hideo Yasunaga, MD, PhD,† Yousuke Nakai, MD, PhD,* Hiroyuki Isayama, MD, PhD,* and Kazuhiko Koike, MD, PhD* Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan* e-mail: [email protected] Department of Clinical Epidemiology and Health Economics, School of Public Health, University of Tokyo, Tokyo, Japan† We appreciate the comments by Dr Aung and colleagues about our recent article (1). Their legitimate concerns about antithrombotic agent users receiving percutaneous drainage of the biliary system clearly implicate clinical questions to be addressed in future studies. In cases where the discontinuation of antiplatelet agents is unacceptable or insufficient, potential measures to prevent severe procedure-related bleeding should be considered. Platelet transfusion is a reasonable procedure that
can restore impaired platelet function, although it is not commonly used in Japan. Theoretically, however, rapid platelet activation might provoke vascular events as with drug discontinuation. Therefore, as often discussed about red cell transfusion (2), the threshold of platelet level and the dose of platelet transfusion should be discussed. Moreover, other specific strategies, for example, desmopressin for patients with chronic renal failure, should be taken into account (3), but a large sample size is required to determine the effectiveness of those countermeasures for a small subset of patients. Endoscopic drainage is less susceptible to bleeding compared with percutaneous drainage and, hence, can be a treatment option for patients at high risk for bleeding (4,5), which is estimated based on risk factors identified in our study. Clinical evaluation of anticoagulant users in the periprocedural period is considerably complicated owing to various confounding factors—for example, warfarin reversal by means of vitamin K, heparin bridging therapy, and freshfrozen plasma administration. In the Society of Interventional Radiology consensus guidelines (3), the international normalized ratio of prothrombin time should be corrected to less than 1.5 in the periprocedural period of both percutaneous biliary drainage and cholecystostomy. As Dr Aung and colleagues advocated, the level of prothrombin time should be considered to treat patients on anticoagulants; unfortunately, however, it was unavailable in the inpatient database used in our study (1). Meanwhile, the management of novel oral anticoagulants (eg, dabigatran, rivaroxaban) deserves an urgent investigation (6). Finally, nationwide multicenter collaboration of interventional radiologists is required to prospectively examine the appropriate management of antithrombotic agents in various specific settings. Disclosures of Conflicts of Interest: T.H. Activities related to the present article: received grants from the Japanese government. Activities not related to the present article: disclosed no relevant relationships. Other relationships: disclosed no relevant relationships. H.Y. Activities related to the present article: received grants
radiology.rsna.org n Radiology: Volume 278: Number 3—March 2016
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from the Japanese government. Activities not related to the present article: disclosed no relevant relationships. Other relationships: disclosed no relevant relationships. Y.N. Activities related to the present article: received grants from the Japanese government. Activities not related to the present article: disclosed no relevant relationships. Other relationships: disclosed no relevant relationships. H.I. Activities related to the present article: received grants from the Japanese government. Activities not related to the present article: disclosed no relevant relationships. Other relationships: disclosed no relevant relationships. K.K. Activities related to the present article: received grants from the Japanese government. Activities not related to the present article: disclosed no relevant relationships. Other relationships: disclosed no relevant relationships.
References 1. Hamada T, Yasunaga H, Nakai Y, et al. Severe bleeding after percutaneous transhepatic drainage of the biliary system: effect of antithrombotic agents—analysis of 34 606 cases from a Japanese nationwide administrative database. Radiology 2015;274(2):605–613. 2. Villanueva C, Colomo A, Bosch A, et al. Transfusion strategies for acute upper gastrointestinal bleeding. N Engl J Med 2013;368(1):11–21. 3. Patel IJ, Davidson JC, Nikolic B, et al. Consensus guidelines for periprocedural management of coagulation status and hemostasis risk in percutaneous image-guided interventions. J Vasc Interv Radiol 2012;23(6):727–736. 4. Sharma BC, Kumar R, Agarwal N, Sarin SK. Endoscopic biliary drainage by nasobiliary drain or by stent placement in patients with acute cholangitis. Endoscopy 2005;37(5):439– 443. 5. Itoi T, Kawakami H, Katanuma A, et al. Endoscopic nasogallbladder tube or stent placement in acute cholecystitis: a preliminary prospective randomized trial in Japan (with videos). Gastrointest Endosc 2015;81(1):111–118. 6. Baron TH, Kamath PS, McBane RD. Man agement of antithrombotic therapy in patients undergoing invasive procedures. N Engl J Med 2013;368(22):2113–2124.
Role of Coronary CT Angiography in Patients with Stroke From Kemal Kara, MD, Ersin Ozturk, MD, and Onur Sildiroglu, MD Department of Radiology, GATA Haydarpasa Teaching Hospital, Uskudar, Istanbul, Turkey e-mail: [email protected]
Editor: We read with interest the article by Dr Lee and colleagues in the August 2015 issue of Radiology titled “Predictors of Recurrent Stroke in Patients with Ischemic Stroke: Comparison Study between Transesophageal Echocardiography and Cardiac CT" (1). The authors evaluated the value of cardiac computed tomography (CT) and compared cardiac CT findings with those from transesophageal echocardiography in patients with ischemic stroke. We would like to share our coronary CT angiography experience with frequently detected abnormalities related to stroke. In the study by Dr Lee and colleagues, the cause of cardiogenic emboli was classified into seven different groups. However, atrial diverticulum may be another etiologic factor and was not mentioned (1). Atrial diverticulum has an important role in the cause and prevalence of thromboembolism and atrial fibrillation (2). In a coronary CT angiography study, the incidence of atrial diverticulum has been reported as 41%, and this ratio is more than the incidence of patent foramen ovale (PFO), which was reported to be 24.9% (3). Valvular vegetation is frequently associated with atrial tachycardia. It is not appropriate to evaluate the images in tachycardia or atrial fibrillation without using a beta-blocker (4). Dr Lee and colleagues stated that they did not use a beta-blocker in their study; however, vegetation could be easily missed in such cases. In addition, the detection of vegetation smaller than 4 mm is very difficult with coronary CT angiography (5). The size of the vegetation should be mentioned as a limitation in the study by Dr Lee and colleagues (1). The importance of a PFO in ischemic stroke was mentioned, but the septal pouch (probe PFO) concept was not emphasized. However, the blood stasis in the septal pouch is included as a new entity in the origin of thromboembolism (6). In conclusion, stroke is a major cause of mortality and morbidity and coronary CT angiography is a highly effective and reliable imaging method for
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detecting the underlying cardiac cause of stroke. Disclosures of Conflicts of Interest: K.K. disclosed no relevant relationships. E.O. disclosed no relevant relationships. O.S. disclosed no relevant relationships.
References 1. Lee K, Hur J, Hong SR, et al. Predictors of recurrent stroke in patients with ischemic stroke: comparison study between transesophageal echocardiography and cardiac CT. Radiology 2015;276(2):381–389. 2. Balli O, Aytemir K, Karcaaltincaba M. Multidetector CT of left atrium. Eur J Radiol 2012;81(1):e37–e46. 3. Incedayi M, Öztürk E, Sonmez G, et al. The incidence of left atrial diverticula in coronary CT angiography. Diagn Interv Radiol 2012; 18(6):542–546. 4. Entrikin DW, Gupta P, Kon ND, Carr JJ. Imaging of infective endocarditis with cardiac CT angiography. J Cardiovasc Comput Tomogr 2012;6(6):399–405. 5. Feuchtner GM, Stolzmann P, Dichtl W, et al. Multislice computed tomography in infective endocarditis:comparison with transesophageal echocardiography and intraoperative findings. J Am Coll Cardiol 2009;53(5):436–444. 6. Krishnan SC, Salazar M. Septal pouch in the left atrium: a new anatomical entity with potential for embolic complications. JACC Cardiovasc Interv 2010;3(1):98–104.
Response From Jin Hur, MD, PhD,* Kyeho Lee, MD,† and Byoung Wook Choi, MD, PhD* Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, 120-752, Seoul, Republic of Korea* e-mail: [email protected] Department of Radiology, Dankook University Hospital, Cheonan city, Chungnam Province, Republic of Korea† We appreciate Dr Kara and colleagues’ interest in our recent work. They have suggested that left atrial septal pouch (LASP) could be another etiologic factor for cardioembolic stroke not mentioned in our recent study (1). 959
