Online Clinical Case Study (June 2017)

Clinical Cardiology Series
臨床心臟科個案研究

The content of the June Cardiology Series is provided by:
Dr. WONG Chi Yuen MBBS (HK), MRCP (UK), FHKCP,
FHKAM (Medicine), Specialist in Cardiology
Dr. CHUI Shing Fung MBChB (CUHK), MRCP (UK), FHKCP,
FHKAM (Medicine), Specialist in Cardiology
六月臨床心臟科個案研究之內容承蒙黃志遠醫生徐城烽醫生提供。

Periprocedural Management of Anticoagulation in Patients with Non-Valvular Atrial Fibrillation

1. Is it always necessary to interrupt anticoagulation in patients undergoing surgical procedures?
A. Yes
B. No
   
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2.

Creatinine Clearance (CrCl) measurement is necessary to determine the timing of interrupting anticoagulation therapy for the following drugs EXCEPT
A. Warfarin
B. Dabigatran
C. Rivaroxaban
D. Apixaban
E. Endoxaban

   
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3.

Pre-operative bridging therapy (unfractionated heparin, UFH or low molecular weight heparin, LMWH) after interruption of anticoagulation is generally NOT necessary for the following drugs EXCEPT
A. Warfarin
B. Dabigatran
C. Rivaroxaban
D. Apixaban
E. Endoxaban

   
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4.

Which of the following factors would be strongly in favor of "No Pre-operative Bridging Therapy" after stopping oral anticoagulation?
A. Prior stroke or transient ischaemic attack
B. Use of aspirin in HIGH thrombotic risk patients
C. Major bleed or intracraninal haemorrhage within 3 months
D. HIGH thrombotic risk patient without increased bleeding risk
E. Recent thromboembolism within 3 months

   
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1. B. No
2. A. Warfarin

Whether to interrupt anticoagulation in patients undergoing surgical procedure depends on the procedural bleed risk, patient-related bleed risk and type of anticoagulation used.

Procedural bleed risks can be classified into 4 risk levels: 1) no clinically important bleed risks; 2) low procedural bleed risk; 3) uncertain procedural bleed risk; or 4) intermediate/high procedural bleed risk. A checklist of some commonly performed procedures can be found in (http://jaccjacc.acc.org/Clinical_Document/PMAC_Online_Appendix.pdf). However, since the complexity of any given procedure may vary, the actual bleed risk maybe different and the opinions of the surgeon should be respected.

Several patient-related factors may also interfere the decision of whether to interrupt anticoagulation before procedure. These include major bleeding of intra-cranial bleeding within 3 months, quantitative or qualitative platelet abnormality, including aspirin use, INR above therapeutic range, prior bleed during previous bridging or similar procedure.

For patients on warfarin, anticoagulation should not be interrupted if they are undergoing procedures with no clinically important or low bleed risk AND absent of patient-related risk factor that increase the risk of bleeding. Warfarin should be interrupted in patients 1) undergoing procedures with intermediate or high bleed risk or 2) undergoing procedures with uncertain bleed risk and the presence of patient-related factor(s) that increase the risk of bleeding. For patients who are undergoing procedures with 1) no clinical important or low bleed risk AND presence of patient -related factor(s) that increase the risk of bleeding, or 2) uncertain bleed risks AND absence of patient-related factor that increase the risk of bleeding, warfarin can be considered to interrupt on the basis of clinical judgment and consultation with the surgeon undergoing procedure (Figure 1).

For patient on novel oral anticoagulants (NOAC) (Dabigatran, Rivaroxaban, Apixaban and Endoxaban), anticoagulation should be interrupted before surgical procedure in the presence of patient-related factor(s) that increase the risk of bleeding. In the absent of patient-related factor that increase the risk of bleeding, NOAC can be continue before procedures with no clinically important bleeding risk but perform at time coincide with the predicted nadir of NOAC's drug level. For patients with no patient-related factor that increase the risks of bleeding undergoing surgical procedures with low, intermediate, high or uncertain bleed-risks, NOAC should be interrupted for a duration based on the estimated CrCl (Figure 2).


Figure 1


Figure 2

3. A. Warfarin.

Given the half-lives of NOACs (6-30hours according to type of NOAC and CrCl of patient), bridging therapy is rarely necessary.

4. C. Major bleed or intracranial hemorrhage within 3 months

Assessment of a patient's thrombotic and bleed risk is essential to determine the need of bridging therapy while warfarin is being held in patient before surgical procedures. Although not validated in the perioperative setting, the CHA2DS2-VASc score (Table 1) can be used to assess the patient's overall thrombotic risk.

Table 1
  Condition Score
C Congestive heart failure 1
H Hypertension 1
A2 Age ≥ 75 years 2
D Diabetes Mellitus 1
S2 Previous stroke or TIA or thromboembolism 2
V Vascular disease (peripheral artery disease, myocardial infarction, aortic plaque) 1
A Age 65-74 years 1
Sc Female sex 1

For those who are at low risk for thromboembolism (less than 5% per year), with a CHA2DS2-VASc score ≤4 or and no previous history of ischemic stroke, TIA, or arterial thromboembolism within 3 months, warfarin can be interrupted with no bridging.

For those who are at high risk of thromboembolism (more than 10% per year), with a CHA2DS2-VASc score of 7 to 9 or recent (within 3month) history of ischemic stroke, TIA, or arterial thromboembolism, bridging therapy should be considered, unless with recent (within 3 months) history of intracranial hemorrhage. For those with high risk of thromboembolism but recent history of intracranial hemorrhage, the procedure should be performed either with no bridging or with post-procedural bridging only.

For those who are at moderate risk of thromboembolism (5% to 10% per year), with a CHA2DS2-VASc score of 5-6 or previous history of ischemic stroke, TIA, or arterial thromboembolism more than 3 months ago, the need of bridging therapy depends on the patient's bleeding risk. For those with increased bleeding risk, interruption of warfarin without bridging is recommended. For those with no significant bleeding risk, use of bridging can be consider for those with previous history of ischemic stroke, TIA or arterial thromboembolism (Figure 3).


Figure 3

Further reading:
2017 ACC Expert Consensus Decision Pathway for Periprocedural Management of Anticoagulation in Patients With Nonvalvular Atrial Fibrillation. Journal of the American College of Cardiology, Volume 69, Issue 7, Pages 871-898. John U. Doherty, Ty J. Gluckman, William J. Hucker, James L. Januzzi, Thomas L. Ortel, Sherry J. Saxonhouse, Sarah A. Spinler

   
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Dermatology Series 皮膚科病例研究

Dermatology Series for June 2017 is provided by:
Dr. LEUNG Wai Yiu, Dr. TANG Yuk Ming, William, Dr. CHAN Hau Ngai, Kingsley, Dr. KWAN Chi Keung and Dr. CHANG Mee, Mimi
Specialists in Dermatology & Venereology
六月皮膚科個案研究之內容承蒙梁偉耀醫生鄧旭明醫生陳厚毅醫生關志強醫生張苗醫生提供。

A young man with brownish macules for years

A thirty-year-old gentleman had a 5-year history of brownish reticulate pigmentation between the shoulder blades and is gradually enlarged to the present size. No complaint of any discomfort except occasional pruritus, and no family history of endocrine neoplasia either.

Answers

1. What is the clinical diagnosis?
The clinical diagnosis is macular amyloidosis (MA). MA is a cutaneous disorder due to abnormal deposition of amyloid in the dermis. Women are commonly affected, usually at the upper back, neck and extensor surfaces of extremities. MA is more common among South American population, as well as Asian and Middle Easterners.
 

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2. What are the differential diagnoses?
Clinical differential diagnoses include post-inflammatory hyperpigmentation, prurigo pigmentosa, lichen simplex chronicus and mycosis fungoides.
 

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3. What are the causes of this skin lesion?
MA is caused by abnormal deposition of amyloid in the dermis but the exact origin of amyloid deposits has not been identified, it was suggested that constant scratching and rubbing could induce the amyloid deposition.
 

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4. How would you confirm the diagnosis?
It is a clinical diagnosis and skin biopsy is rarely necessary unless in doubtful cases.
 

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5. What other investigations would you do?
MA can be associated with multiple endocrine neoplasia syndrome and relevant blood and urine tests should thus be conducted for those patients with positive family history.
 

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6. How would you treat this patient?
Apart from cosmetic disability, symptomatic pruritus should be addressed as it is the primary trigger for deposition of amyloid and scratching may aggravate skin pigmentation. Sedating antihistamines, topical or intralesional steroid is effective in relief of itchiness. Phototherapy, surgical treatment such as laser and dermabrasion, are reported with effect in recalcitrant cases but recurrence is not infrequent.
 

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