N. M. is a 75-year-old woman with a long-standing history of HF secondary to viral cardiomyopathy. She presents to the outpatient clinic for routine follow-up. On examination, she was short of breath and reported increasing orthopnea. She was admitted to the ICU for right heart catheterization. Initial readings show a cardiac index of 1.8 L/min/m2 , elevated pulmonary capillary wedge pressure (25 mmHg), and high pulmonary pressures (72/45 mmHg). Her initial BP was 105/55 mmHg, and she had a heart rate of 105 beats per minute (bpm). Home medications include captopril, spironolactone, metoprolol XL, and furosemide. Which of the following inotropic agents would be most appropriate?
c. Milrinone. Milrinone is a phosphodiesterase inhibitor classified as inodilator. Thus, milrinone produces positive inotropic effects and vasodilation. Milrinone inhibits the phosphodiesterase III enzyme, leading to an increase in intracellular cAMP, thus causing increased intracellular levels of calcium. In addition, milrinone will decrease pulmonary pressures and left ventricular (LV) end-diastolic pressures more predictably than the other agents listed. These combined effects lead to minimal increases in myocardial O2 consumption. Also, milrinone may be useful in this patient secondary to chronic metoprolol therapy.
Which of the following statements is true regarding vitamin K administration?
c. IV vitamin K works faster to lower the INR than oral vitamin K at similar doses. The onset of action of IV vitamin K is 1–2 hours compared to 6–10 hours for oral vitamin K. As a result, INR values return to normal quicker with IV vitamin K. The overall reduction in INR is dose dependent and not route dependent when comparing IV and oral formulations. Subcutaneous vitamin K has variable absorption which can lead to variations in time to onset as well as INR lowering effect.
Which of the following agents bind only to factor Xa?
b. Fondaparinux. Fondaparinux, a pentasaccharide, selectively inhibits activated Xa through its binding to antithrombin. Enoxaparin and UFH bind to both thrombin (IIa) and activated Xa, whereas bivalirudin binds directly to thrombin. UFH binds to thrombin and activated factor Xa in a 1:1 ratio, whereas LMWHs vary in their binding ratios.
A. F. is a 52-year-old man with a history of AFib, transient ischemic attacks, hypertension (HTN), and rheumatic heart disease. The recommendations from the Sixth American College of Chest Physicians (ACCP) Consensus Conference on Antithrombotic Therapy suggest that this patient be initiated on _____ for antithrombotic therapy because of AFib.
c. Warfarin, with a target goal international normalized ratio (INR) of 2.5. This patient is at high risk for a thromboembolic event. Recommendations for antithrombotic therapy include risk stratification. Risks are stratified into high, moderate, and low. High-risk patients include patients with prior stroke or transient ischemic attack or systemic embolus, history of HTN, poor LV systolic function, age older than 75 years, rheumatic mitral valve disease, and a prosthetic heart valve. Moderate risk factors include age between 65 and 75 years, DM, and CAD with preserved LV systolic function. Low-risk patients are those younger than 65 years old with no clinical or transthoracic echocardiogram evidence of cardiovascular disease.
The patient above is going to be electively cardioverted. What is the timing of PO anticoagulant therapy?
c. Warfarin with a target INR of 2.5 for 3 weeks before cardioversion and continued for 4 weeks after cardioversion. Recommendations from the Sixth ACCP Consensus Conference on Antithrombotic Therapy state that patients undergoing elective cardioversion for AFib should be initiated on oral anticoagulant therapy for 3 weeks before and at least 4 weeks after elective direct current cardioversion. The grade of evidence is 1C+. Also, an alternative approach would be to initiate anticoagulation, have the patients undergo a transesophageal echocardiography, and have the cardioversion performed if no thrombi are seen. Warfarin should be continued for at least 4 weeks, as long as the patient maintains normal sinus rhythm. This is a grade 1C recommendation.
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