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MANAGEMENT OF HEMORRHAGE IN PATIENTS WITH MECHANICAL HEART VALVES. Clinical Scenario.
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MANAGEMENT OF HEMORRHAGE IN PATIENTS WITH MECHANICAL HEART VALVES
Clinical Scenario • Mr. H.R. is a 62 y.o. white male with PMHx. of CAD and Aortic Stenosis. He underwent 3 vessel CABG and AVR with St. Jude Valve approximately 4 years ago. Admitted for elective knee arthroscopy and “Heparin Window”. 48 hours post-op developed acute drop in Hgb and left flank pain. Abdominal CT revealed large left retroperitoneal hematoma.
CLINICAL QUESTIONS • What is the risk of temporarily interrupting anticoagulation in a patient with a mechanical heart valve? • How long should anticoagulation be held in patients with bleeding and mechanical heart valves?
INTRODUCTION • In March 1960, the first successful replacement of an aortic valve was performed by Harkin. • Approximately 60,000 valve repairs are performed annually in the U.S. • More than 80 models of prosthetic heart valves have been developed since the 1950s.
TYPES OF PROSTHETIC VALVES • Prosthetic heart valves may be mechanical or bioprosthetic. • Mechanical valves are very durable, most lasting at least 20 to 30 years. • 10 to 20 percent of homograft bioprostheses and 30 percent of heterograft bioprostheses fail with 10 to 15 years of implantation.
TYPES OF PROSTHETIC HEART VALVES • MECHANICAL • Caged-ball Starr-Edwards • Single-tilting-disk Bjork-Shiley • Medtronic-Hall • Omnicarbon • Bileaflet-tilting-disk St. Jude Medical • Carbomedics • Edwards-Duromedics • BIOPROSTHESIS • Heterograft Hancock • Carpentier-Edwards • Homograft
INCIDENCE RATES OF VALVE THROMBOSIS AND MAJOR AND TOTAL EMBOLISMS • Incidence Rates per 100 Patient-Years • Anticoagulation Valve Thrombosis Major Emb. Total Emb. • NONE 1.8 (0.9-3.0) 4.0(2.9-5.2) 8.6 (7-10.4) • Antiplatelet 1.6 (1-2.5) 2.2(1.4-3.1) 8.2(6.6-10) • Coumadin 0.2(0.2-0.2) 1.0(1.0-1.1) 1.8(1.7-1.9) • Coumadin + AP 0.1(0-0.3) 1.7(1.1-2.3) 3.2(2.4-4.1) • Major embolism defined as causing death, residual neurologic deficit, or peripheral ischemia requiring surgery.
RISK FACTORS FOR EMBOLIZATION • Mitral valve prosthesis • Multiple prosthetic valves • Caged-ball valves • Prior CVA • Atrial Fibrillation • Age greater than 70 • Depressed left ventricular function
DAILY RISK OF WITHOLDING ANTICOAGULATION • Without anticoagulation, the risk of major embolism is 4 per 100 patient-years and the risk of thrombosis is 1.7 per 100 patient-years. • The yearly risk of an event would be 5.7%. However, the risk for 1 day would only be (4+1.7)/365 = 0.016%.
STUDIES WHICH SUBSTANTIATE A LOW DAILY RISK • Very limited data available on the risk of thromboembolism following discontinuation of warfarin because of bleeding. • Previous studies have focused on the interruption of warfarin prior to non-cardiac surgery. • Available data is limited to case reports and small case series
Intra-cranial Hemorrhage • Gomez et al., reported a case of hypertensive cerebral hemorrhage in a patient on warfarin for a Bjork-Shiley aortic valve. Warfarin was re-instituted after 10 days without further bleeding or thromboembolic phenomenon. • Babikian et al., reported a series of six patients hospitalized with intra-cerebral bleed. Five patients survived initial event. Warfarin therapy was withheld a mean of 19 days without any thromboembolic events during the 6 months of follow up.
Ananthasubramaniam et al: How Safely and for How Long Can Warfarin Therapy Be Withheld in Prosthetic Heart Valve Patients Hospitilized With a Major Hemorrhage? • Design - Retrospective medical record review • Methods - Retrospective review of 28 patients with prosthetic heart valves who were hospitalized with a major hemorrhage in the Henry Ford Hospital from 1990 to 1997.
Demographics 28 patients included Mean age 61 ± 11 years 15 men and 13 women 35% with atrial fibrillation 32% with prior CVA 39% with LV dysfunction Primary Diagnosis 25 patients (89%) with GI Hemorrhage 2 patients with intra-cerebral hemorrhage 1 patient with subdural hematoma PATIENT POPULATION
TYPE 32 valves were present in 28 patients. 24 St. Jude valves 2 Bjork-Shiley valves 2 Starr-Edwards valves 4 Carpentier-Edward bioprosthetic valves. POSITION 12 patients with valves in mitral position. 12 patients with valves in the aortic position. 4 patients with combined mitral and aortic valves. VALVE POSITION AND TYPE
ANTICOAGULATION STATUS AT ADMISSION • 16 patients (57%) with within therapeutic range. • 7 patients (25%) within the sub-therapeutic range. • 5 patients (18%) with supratherapeutic anticoagulation.
REVERSAL OF ANTICOAGULATION • Five of the 28 patients (17%) received no specific treatment for correction of INR/PT. • 7 patients (30%) received FFP. • 5 patients (21%) received Vitamin K. • 16 patients (69%) received PRBCs.
SUMMARY OF IN-HOSPITAL COURSE • Mean duration of warfarin withholding was 15 ± 4 days. Seven patients (25%) had warfarin withheld for 1 to 7 days, 13 patients (46%) for 7 to 21 days, and 8 patients (28%) for > 3weeks. • Four in-hospital deaths felt due to complications of initial hemorrhage. • NO THROMBOEMBOLIC EVENTS DURING HOSPITILIZATION.
DISCHARGE ANTICOAGULATION • Twenty-two of the 24 patients were restarted on warfarin therapy and had reached an INR > 2.0 at the time of discharge. • Both patients discharged without warfarin therapy had a history of recurrent bleeding episodes. • One patient with a St. Jude Aortic Valve was discharged on ASA. • The other patient with a St. Jude mitral valve was discharged without any anticoagulation.
SIX MONTH FOLLOW UP • 21 of the 24 patients were available for follow up (all three patients had been restarted on warfarin prior to discharge). • In the 19 patients who were discharged on warfarin and available for follow up, there were no clinically recognized thromboembolic events. • The patient discharged without anticoagulation died suddenly at home 4 months after discharge, and no autopsy was performed. • The patient discharged on ASA had no thromboembolic events. • 10 patients receiving warfarin had recurrent GI bleeding but only 2 had to be hospitalized.
CONCLUSIONS • At six months, there were no thromboembolic events in hospitalized patients with anticoagulation withheld for a mean of 15 ± 4 days. • This suggests that warfarin may be withheld from 14 to 21 days with a low risk of thromboembolism. • Over half of the patients with GI bleeding had a recurrence within 6 months.
LIMITATIONS • Small study population and three of the patients discharged on warfarin were lost to follow up. • The thromboembolic risk may be underestimated , since the majority of the patients had St. Jude valves and single prosthesis.
CLINICAL APPLICATION • Daily risk of thromboembolic events in patients with prosthetic valves unable to tolerate anticoagulation is low (0.016%). • Limited data seems to agree that the risk of discontinuation of therapy is low. • The source of bleeding should be aggressively evaluated and treated. • Above all, physicians must balance the risk of bleeding vs. the benefits of anticoagulation.
H.R.’s HOSPITAL COURSE • Heparin drip was discontinued. • Patients HGB stabilized with 2 U PRBC. • Patient scheduled to follow up with PCP at 2 weeks from stabilization of HGB for CBC and evaluation. • If stable, he will resume prior dose of coumadin with goal INR b/t 2.5-3.5.