An 86-year-old female presents with lower gastrointestinal hemorrhage requiring massive transfusion. The bleeding subsides without additional intervention; however, persistent hypotension is encountered. Coagulation studies are normal except for a slightly prolonged activated partial thromboplastin time (aPTT). Echocardiography from 6 months ago demonstrates peak/mean aortic valve gradient of 80/40 mm Hg, with an estimated aortic valve area of 0.8 cm2 and reduced left ventricular function.
Which coagulation abnormality should be expected?
Correct Answer: B
This patient has severe aortic stenosis and has developed cardiogenic shock in the setting of acute gastrointestinal hemorrhage. Gastrointestinal bleeding in patients with severe aortic stenosis is not uncommon. Heyde syndrome refers to the triad of aortic stenosis, gastrointestinal angiodysplasia, and an acquired type IIA von Willebrand disease. von Willebrand factor serves as the major adhesion molecule that attaches platelets to exposed endothelium. In addition, von Willebrand factor binds factor VIII, extending its half-life in circulation. High shear stress caused by severe aortic stenosis leads to platelet aggregation and induction of von Willebrand factor–cleaving metalloproteinase. This metalloproteinase reduces the high molecular weight multimers of von Willebrand factor resulting in type IIA von Willebrand disease.
The coagulation panel of patients with von Willebrand disease is nonspecific. The aPTT may be normal or elevated. The concentration of von Willebrand factor (vWF:Ag) and the activity of von Willebrand factor (vWF:RCo) can diagnose the disease, help classify the subtype, and direct therapy. There are three primary classifications of von Willebrand disease. Type I is the most common and results from a quantitative decrease in functional von Willebrand factor. Type II results from functional deficits in von Willebrand factor and is divided into four subtypes—A, B, M, N. Acquired type IIA von Willebrand disease, as seen in this patient, results in loss of intermediate and high molecular weight von Willebrand multimers. Type III von Willebrand disease describes patients with no von Willebrand factor and extremely low levels of factor VIII.
In acquired von Willebrand disease due to aortic stenosis, the coagulation abnormalities will return to normal following aortic valve replacement. Before correction, the mainstay of treatment is 1-deamino-8- D-arginine vasopressin (DDAVP), which promotes the release of von Willebrand factor and factor VIII from endothelial cells. Intravenous DDAVP can be given as a 0.3 mcg/kg bolus with a peak effect at 30 minutes. The most common side effect is hyponatremia due to the medication’s effect on free water clearance. Concentrated von Willebrand factor can be administered to patients with life-threatening bleeding or type III disease.
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A 68-year-old female with severe chronic obstructive pulmonary disease experienced a syncopal event while climbing the stairs at home. She presented to the emergency department with multiple rib and upper extremity fractures as well as a displaced hip fracture. Following an urgent hip fracture repair, she arrives to the ICU intubated and sedated. On physical examination, she has a laterally displaced point of maximal impulse with a systolic murmur heard best at the left sternal border.
Which transthoracic echocardiographic view would best aid in diagnosis and grading of severity?
Correct Answer: C
Given the physical examination findings, this patient likely has aortic stenosis. The degree of aortic stenosis is best evaluated in the apical 5- chamber and 3-chamber views. The apical 5-chamber view is obtained by tilting the probe anterior from the apical 4-chamber view until the left ventricular outflow tract and aortic valve come into view. The apical 3- chamber view is obtained rotating the probe counterclockwise at 60° from the apical 4-chamber view until the left atrium, left ventricle, left ventricular outflow tract, and aortic valve appear. Utilizing these views, continuous wave Doppler can be applied to obtain the velocity and gradient across the aortic valve. Valvular hemodynamic parameters classifying the degree of aortic stenosis are presented in the table below:
Aortic stenosis increases both the systolic and diastolic pressures of the left ventricle. Gradually increased systolic pressure leads to concentric left ventricular hypertrophy and myocardial remodeling. According to the Law of LaPlace (S = Pr/h; S = systolic wall stress, P = pressure, r = ventricular radius, and h = ventricular thickness), left ventricular hypertrophy results in increased wall thickness and therefore decreased wall stress. This hypertrophy can displace the point of maximal impulse laterally and may lead to the development of a fourth heart sound, S4 . Furthermore, the left ventricular ejection time is increased, which decreases the time spent in diastole. Increased left ventricular diastolic pressure combined with a decreased time in diastole will decrease coronary perfusion and promote myocardial ischemia.
The definitive management of patients with aortic stenosis is aortic valve replacement. ICU management focuses on the following hemodynamic goals: correction of hypovolemia (decreased preload), avoidance of tachycardia, normal but not augmented inotropy and aggressive treatment of hypotension (maintaining afterload). Maintaining left ventricular filling pressure is vital to promote ejection in the setting of high transvalvular gradients. Reduced afterload should be aggressively treated and counteracted to increase diastolic blood pressure and restore coronary perfusion pressure. It is also important to avoid increases in myocardial oxygen demand such as pain, tachycardia, and other increases in sympathetic drive. In summary, the main hemodynamic goals in patients with severe aortic stenosis are to maintain adequate preload, increase afterload, avoid tachycardia, and maintain normal contractility.
A 46-year-old female with a history of hepatitis C and intravenous drug abuse presents to the emergency department with fevers, rigors, confusion, and acute shortness of breath.
The vital signs are as follows:
Chest radiograph shows diffuse pulmonary edema. Echocardiography demonstrates a vegetation on the noncoronary cusp of the aortic valve with severe aortic regurgitation. Although awaiting surgery, the patient is admitted to the cardiology ICU.
Which intervention in the most appropriate next step?
Correct Answer: A
Acute aortic regurgitation can lead to rapid cardiovascular and respiratory deterioration. The left ventricle cannot accommodate the acute rise in left ventricular preload, and as a result, stroke volume decreases. Left ventricular diastolic pressure rises rapidly causing premature closure of the mitral valve in diastole. Further increases in left ventricular pressure may cause a phenomenon known as diastolic mitral regurgitation, which increases the pressures in the left atrium and pulmonary circulation. Patients with acute aortic regurgitation may present with tachycardia, hypotension, and pulmonary edema. Cardiogenic shock in the setting of acute aortic regurgitation is an indication for emergent aortic valve replacement. Inotropic agents (dobutamine) and/or vasodilators (nitroprusside) may be required to temporize the hemodynamics before the procedure. Nitrodilators cause venous and arterial vasodilation resulting in decreased preload and afterload. Addition of dobutamine may also improve cardiopulmonary function by increasing inotropy and decreasing systemic vascular resistance and thus afterload. Patients with severe aortic regurgitation have wide pulse pressure due to the rapid aortic run off. Decreasing left ventricular afterload helps to decrease the gradient between the aorta and the left ventricle in diastole, thus reducing the regurgitant volume.
Chronic aortic regurgitation, on the other hand, results in myocardial remodeling, which tolerates increased preload to a much greater extent than acute aortic regurgitation. In chronic aortic regurgitation, gradually increased left ventricular diastolic pressures result in eccentric left ventricular hypertrophy. Because of the eccentric hypertrophy, the increased preload can increase stroke volume and cause increased systolic pressures. This in turn increases left ventricular ejection time and thus decreases diastolic time resulting in decreased coronary perfusion. However, according to the law of Laplace, left ventricular dilation (increased radius) leads to increased wall tension and thus increased afterload. Thus, chronic aortic regurgitation represents a state of both increased preload and increased afterload.
A 78-year-old male presents to the ICU with chest pain, shortness of breath, and respiratory distress requiring urgent intubation. The chest radiograph shows diffuse pulmonary edema, worse in the lower lung lobes.
His vital signs are as follows:
The patient’s electrocardiogram demonstrates ST-segment elevation in lead II, III, and aVF with reciprocal changes in leads I and aVL. On physical examination, he has a systolic murmur, bilateral crackles on lung auscultation, and cold and clammy extremities. Cardiac enzymes are pending.
What interventions should be considered?
This patient developed flash pulmonary edema secondary to an acute posteromedial papillary muscle rupture in the setting of an inferior wall ST-elevation myocardial infarction. Papillary muscles are vulnerable to myocardial ischemia because they are perfused by the terminal portion of the coronary arteries. This can result in transient papillary muscle dysfunction or frank rupture. The posteromedial papillary muscle is more frequently involved because it is supplied by the posterior descending branch of the right coronary artery, whereas the anterolateral papillary muscle has a dual blood supply including the diagonal branches of the left anterior descending artery and the marginal branches of the left circumflex artery. Acute mitral regurgitation can occur because of infective endocarditis, myocardial ischemia, papillary muscle or chordae rupture, and prosthetic valve malfunction. Mitral regurgitation causes an abrupt increase in left ventricular end diastolic volume (preload) and a reduction in forward stroke volume. An important hemodynamic difference between acute and chronic mitral regurgitation is left atrial compliance. In chronic mitral regurgitation, the left atrium dilates with time and compliance increases gradually as the regurgitant volume increases. In acute mitral regurgitation, normal or decreased left atrial compliance cannot tolerate an abrupt increase in volume. This leads to pulmonary edema, pulmonary hypertension, and right ventricular failure.
Emergency surgery is indicated in patients with acute left ventricular failure due to ruptured papillary muscles. Placement of intra-aortic balloon pump may exert some beneficial physiologic effects in the setting of acute mitral regurgitation. These include improved coronary perfusion, decreased left ventricular afterload, and improved cardiac index. Afterload reduction with vasodilators such as nitroprusside will also improve forward flow; however, if the patient is in cardiogenic shock, this may not be tolerated. If hypotensive, increased inotropy with dobutamine is preferable to norepinephrine. Increased alpha-1 stimulation will increase afterload and may worsen the regurgitant volume and increase pulmonary pressures. Increased inotropy combined with afterload reduction can promote forward flow and decrease regurgitant fraction, while increasing blood pressure. Inhaled epoprostenol decreases pulmonary vascular resistance and is indicated in patients with an increased transpulmonary gradient (mean pulmonary artery pressure minus left atrial pressure); however, it has no role in case of left ventricular failure. Inhaled epoprostenol causes pulmonary arterial vasodilation, which may in fact increase the gradient between the pulmonary venous to pulmonary arterial circulation and worsen the venous congestion.
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A 46-year-old female with a history of hypertension, intracranial arteriovenous malformation, and previous mechanical mitral valve replacement is admitted to cardiology ICU with new onset of atrial fibrillation, shortness of breath, tachypnea, and crackles at both lung bases on auscultation.
The patient has:
International normalized ratio (INR) is 1.8. Transesophageal echocardiography demonstrates the following image of the bioprosthetic mitral valve (red arrows) in the midesophageal two-chamber view. The mean transmitral gradient was measured 12 mm Hg with continuous wave Doppler.
What is the next step in management?
Prosthetic valve thrombosis should be suspected in the setting of new onset heart failure, thromboembolism, or valve dysfunction in a patient with a mechanical valve. The incidence is estimated to be 0.3% to 1.3% per year. Thrombosis is more common on right-sided valves versus left-sided valves, the mitral valve versus aortic valve, and mechanical valves versus bioprosthetic valves. Anticoagulation therapy for all patients with a valve replacement includes daily aspirin with or without a vitamin K antagonist. The presence of a mechanical mitral valve requires lifelong vitamin K antagonist therapy with INR targets 2.5 to 3.5. This patient has an INR of 1.8 and is therefore subtherapeutic and at increased risk for prosthetic valve thrombosis. INR targets after mechanical aortic valve replacement require an INR of 2.0 to 3.0 because the higher velocity of flow through the valve helps to prevent blood stasis. Treatment of prosthetic valve thrombosis includes systemic anticoagulation, thrombolytic therapy, and/or surgery. Patients with subtherapeutic anticoagulation should receive intravenous heparin therapy. The 2014/2017 American College of Cardiology/American Heart Association guidelines recommend emergent surgery or low-dose thrombolytic therapy for patients with left-sided prosthetic valve thrombosis and signs of valve obstruction or heart failure. Patients with right-sided thrombosis are candidates for thrombolytic therapy. This patient has a history of an intracranial arteriovenous malformation, which is an absolute contraindication to thrombolytic therapy; therefore, urgent surgery should be pursued. Other absolute contraindications to thrombolysis include active internal bleeding, recent history of stroke, intracranial or spinal surgery, serious head trauma, intracranial neoplasm or aneurysm, and severe uncontrolled hypertension.
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