A CASE OF PROSTHETIC MITRAL VALVE WITH CHRONIC ATRIAL FIBRILLATION

FOR EXPLORATORY LAPAROTOMY.

Dr N.G. Tirpude( HOD, dept of

Anesthesiology GMC Nagpur)

Dr. Bakshi (Asso. Poof)

Dr. V. Ankalwar(Asso. Prof)

Dr. Abhijeet Patil

INTRODUCTIONA case of prosthetic mitral valve on anticoagulants with chronic AF presents a great preoperative, intraoperative and postoperative challenge to an anesthetist due to risks involved such as infective endocarditis, thromboembolism, life threatening arrhythmias and excessive bleeding .

CASE REPORT A 43 yr women k/c/o RHD with MVR( )

done in 2005 with chronic atrial fibrillation Presented with c/o pain in abdomen since

2 months Diagnosed with lump in abdomen posted

for exploratory laparotomy She was on - T. warfarin 7.5 mg

(current INR 2.2) T. Digoxin 0.25 mg T. Verapamil 40 mg

GENERAL EXAMINATION Thin built , pale Afebrile PR- 74/min irregularly irregular with

apex pulse deficit 20-30 beats (HR>PR) BP- 130/90 mmHg Rt UL supine CVS- metallic click + at apex RS, P/A, CNS- WNL

INVESTIGATIONS Hb 11 g/dl INR 1.2 LFT, KFT, Sr electrolytes- WNL ECG s/o atrial fibrillation with HR of

84/min. 2D ECHO s/o prosthetic valve in situ ,

LVEF 45% no atrial clot no vegetation CT SCAN s/o well defined solid cystic

lesion in pouch of Douglas 8x4x5 cm

CXR

SHIFTING OF PATIENT FROM ORAL ANTICOAGULANTS TO UFH

T. warfarin was discontinued 4 days prior to surgery

Pt was shifted on sc unfractionated heparin 4000 IU QID

Heparin was discontinued 6 hrs before surgery

T. verapamil and T.digoxin were continued till the morning of surgery

ANESTHETIC MANAGEMENT On the day of surgery infective

endocarditis prophylaxis given INR was 1.2 2FFP & 1 PCV kept ready Defibrillator was kept ready On OT table vitals - - SpO2 - 99% on air - HR on ECG 104/ min irregularly irregular - BP - 130/90 mmhg

Epidural anesthesia was planned Epidural catheter was secured in L3-L4

space Intravascular placement of catheter was

excluded by absence of blood on aspiration

Bolus doge of 2% lignocaine 6cc with bupivacaine 12 cc diluted to 20cc was given with 0.3 ml sodabicarbonate.

After 20 min adequate level of anesthesia was achieved up to T8-T10

Intraop vitals - PR 90-115/min irregular - SBP 90- 130 mmHg - SpO2 99% Sedation with fentanyl 25+25 mcg 3 mg Mephentermine was required only

once 500 ml crystalloids were required intraop Encapsulated hematoma of 8x4x5 cm was

removed from Pouch of Douglas Surgery took around 90 mins

Epidural catheter was removed after giving analgesic dose of 6cc 0.125% bupivacaine with buprenorphine 100 mcg

Pt was shifted to recovery room for observation

Post op period was uneventful Since intraop hemostasis was satisfactory,

abdominal drains showed no excess bleeding, we chose to restart heparin within 6 hours of removal of epi.catheter and continued for 48 hours. And warfarin was started on next day.

DISCUSSION Pts on mechanical prosthetic heart valve

needs proper anticoagulation as pt is exposed to significant threat of TE and valve dysfunction

Target INR is achieved with warfarin

Type of valve Target INR

New generation 2.5-3.5

Older types 3.5-4.5

Tricky situation for anesthesiologist perioperatively

discontinuation of cont. OACOAC

Life threatening TE Significant BleedingWith AF risk is 1-20% risk high

OPTIONS FOR MANAGING PERI-PROCEDURAL ANTICOAGULATION

-First, OAC can be continued during procedures associated with low rates of bleeding. - Second, OAC can be interrupted for several days prior to the procedure and resumed immediately following the procedure. -Third, OAC can be interrupted with bridging anticoagulation, using either heparin or low molecular weight heparin (LMWH)

WHICH PATIENT ON WARFARIN SHOULD RECEIVE HEPARIN FOR BRIDGING?High risk for TE:bridging adviced

Intermediate risk of TE : bridging on case to case basis

Low risk for TE : bridging not advised

- AF with mechanical heart valve in any position

- Rheumatic AF- Older

mechanical valve model

- Recently placed mitral valve(< 3 month)

- AF with history of cardiac embolism

- Venous or arterial TE in last 1-3 month

- Known hypercoagulable state

- Cerebrovascular disease with multiple strokes or TIA without risk factors for cardiac embolism

- Newer mechanical valve models in mitral position

- AF without history of cardiac embolism

- Venous TE >3-6 months

- AF without multiple risks for cardiac embolism

- Newer model prosthetic valve in aortic position

- intrinsic cerebrovascular disease without stroke

As our pt was in high risk group we decided to bridge the pt with unfractionated heparin(UFH) according to ACCP guidelines which suggests Discontinue OAC at least 3 days before major

surgery. Start SC conventional heparin or LMWH in

prophylactic doses. Last dose before 3-6 hours preoperatively. Restart heparin as soon as possible post

operatively (within 12 hour) and continue till 48 hours to enable reduction in vitamin K dependent clotting factors

Start warfarin within 24 hrs post operatively

In case of emergency surgery , effect of warfarin needs to be neutralized by FFP , the dose of which depends on individual and titrated till INR < 1.5.In addition, IV vitamin K can be given in small doses.

In our case we could also achieve INR 1.2 which was safer to proceed for surgery with regional anesthesia.

ATRIAL FIBRILLATION Patient was already in chronic AF. Noxious stimulus can precipitate - acute on chronic AF. - ventricular arrhythmias. - ventricular fibrillation. Our strategy to reduce risks due to AF was - control ventricular rate - prevention of thromboembolism - antiarrhythmic drugs and defibrillator was kept ready - tab.Verapamil & tab.Digoxin cont.till day of surgery.

CHOICE OF ANESTHESIA We decided to use epidural anesthesia in this

pt instead of GA TO AVOID

- stress response associated with laryngoscopy intubation and extubation , inadequate depth-life threatening arrhythmias - direct cardio depressant

effects of iv and inhalationalanesthetics-hemodynamic instability

- respiratory complications

TO ACHIEVE : - better analgesic profile - hemodynamic stability - better post op analgesia -less intraop blood loss

-better hemostasis-lesser cardiac and respiratory

complications

Use of LA with adrenaline for epidural test dose should be avoided as it can cause tachyarrhythmia, angina, ischemia, hypertension which could have been fatal in this case.

CONCLUSION Key points to success - Bridging with unfractionated heparin 4-5 days prior to surgery, - INR maintained < 1.5 for proceeding with surgery , - to prevent possible bleeding problems and to administer neuraxial block discontinuation heparin 6 h prior to surgery and restarted within 6-12 h after surgery. - Infective endocarditis prophylaxis should be given to all patients with prosthetic heart valve. - Antiarrhythmic drugs and defibrillator should be kept ready.

This case was managed successfully under epidural anesthesia without any complications

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