A 60-year-old male with a history of nonischemic dilated cardiomyopathy is admitted to the intensive care unit (ICU) after presenting to the emergency department with several days of progressive dyspnea and lower-extremity swelling. He is found to be hypotensive and tachycardic and on examination is noted to be confused with edematous, cool extremities. A 12-lead ECG shows rapid atrial fibrillation with nonspecific ST-segment changes. His last transthoracic echocardiogram performed 1 year ago showed a severely dilated LV cavity with a left ventricular ejection fraction of 28%, severe mitral regurgitation, moderate aortic insufficiency, and severe tricuspid regurgitation.
In this patient, which of the following represents a contraindication to the use of an intra-aortic balloon pump (IABP)?
Correct Answer: C
IABP counterpulsation is a commonly used form of mechanical circulatory support that involves placement of a catheter with a heliumfilled balloon into the proximal descending aorta via the common femoral artery under fluoroscopic guidance. The balloon is inflated just after the aortic valve closes and deflates before the opening of aortic valve. This results in blood displacement toward the proximal aorta during diastole while the balloon is inflated, and a suction effect in the aorta during systole when the balloon is rapidly deflated. The resulting hemodynamic changes include a reduction in systolic blood pressure (to reduce myocardial wall stress and work), an increase in diastolic blood pressure, and an increase in the mean arterial pressure. Some studies have shown that IABP counterpulsation results in an increase in total coronary blood flow.
Contraindications to the use of IABP counterpulsation include severe peripheral arterial disease, aortic dissection or significant aortic aneurysm, and severe coagulopathy. IABP is contraindicated in moderate or greater aortic insufficiency, as inflation of the balloon during diastole will increase regurgitant flow across the aortic valve and worsen heart failure. Atrial fibrillation is not a contraindication to using IABP. IABP counterpulsation decreases preload and thus is beneficial in LV dilation, mitral regurgitation, and tricuspid regurgitation.
A 78-year-old male is admitted to the ICU to undergo evaluation for urgent coronary artery bypass grafting after a coronary angiography revealed critical left main artery stenosis. During the catheterization procedure, an IABP was placed via the left common femoral artery because of ongoing chest pain. Chest pain abated after the IABP was placed. After several hours in the ICU, the patient complains of mild recurrent chest pain, and his nurse reports that there is new blood that can be seen in the IABP catheter that is connected to the console.
Which of the following is the most appropriate next step in the management of this patient?
Correct Answer: D
Although the IABP is a widely used tool in the management of a variety of acute cardiac conditions, it is associated with complications occasionally. The presence of blood in the IABP catheter indicates balloon rupture, and the device should be immediately removed. Rarely, balloon rupture can result in thrombosis or balloon entrapment within the arterial tree and may require surgical exploration for safe removal. Blood in the IABP catheter is clearly indicative of balloon rupture, and no other investigations are necessary for diagnosis. Other important complications of IABP use include limb ischemia, vascular laceration, and hemorrhage. In one large review of 17,000 patients who underwent IABP placement, 7% of patients had at least one complication, whereas 2.6% suffered a major complication (acute limb ischemia, balloon rupture, significant bleeding, or death related directly to the IABP).
A 43-year-old woman is admitted to the ICU with palpitations and dyspnea because she is 10 weeks from successful orthotopic heart transplantation for severe idiopathic dilated cardiomyopathy. Her posttransplant course has been uneventful thus far. On admission her:
Her physical examination is notable for:
Her cardiac examination reveals:
A 12-lead ECG shows rapid atrial fibrillation.
Which of the following is the next best diagnostic test to obtain in the management of this patient?
Correct Answer: A
This patient is presenting with new atrial fibrillation as well as signs and symptoms of heart failure, which in a patient with a recent cardiac transplant is highly concerning for acute cardiac allograft rejection. Any suspicion for acute rejection should prompt an urgent evaluation with an endomyocardial biopsy to try and establish the diagnosis. Echocardiography is not specific for diagnosing rejection. Although cardiac MRI may be used as a screening tool, endomyocardial biopsy still remains the gold standard for diagnosis of allograft rejection. Coronary allograft vasculopathy or coronary artery disease may be diagnosed with coronary angiography but typically occurs years after transplantation.
The incidence of any rejection in the first year after transplant reaches 25%, and the incidence of rejection requiring treatment is reported to be about 13%. The risk of developing acute rejection is much higher early after transplant, peaking at one month posttransplant and declining thereafter. Clinical symptoms of acute rejection are typically related to left ventricular systolic dysfunction and can include dyspnea, orthopnea, paroxysmal nocturnal dyspnea, peripheral edema, and gastrointestinal symptoms. Importantly, acute cellular rejection can present with atrial arrhythmias including both atrial fibrillation and atrial flutter. Once a diagnosis is made, the type of treatment varies based on histologic criteria as well as the presence of symptoms and/or hemodynamic compromise. In general, oral or intravenous corticosteroids and antithymocyte globulin are the mainstays of acute rejection therapy.
A 64-year-old man with a history of coronary artery disease and severe ischemic cardiomyopathy is brought to the hospital by his wife, who found him at home confused and lethargic. He has a durable continuous flow left ventricular assist device (LVAD) that was surgically implanted 1 year ago as destination therapy for his end stage heart failure. On arrival he is arousable but somnolent. His blood pressure is unable to be obtained with a manual cuff; however, a reading obtained with a Doppler ultrasound is 54 mm Hg. His heart rate is 119 beats per minute, respirations are 26 per minute, and his temperature is 38.0°C. On examination, his jugular venous pressure is 5 mm Hg, his cardiac examination reveals a continuous hum, his peripheral pulses are not palpable, and his extremities are warm without significant edema. Interrogation of his LVAD shows high flow with normal power.
Which of the following would NOT be an appropriate intervention in the acute management of this patient?
This patient is presenting with clinical features consistent with sepsis and should be treated with aggressive early intervention based on surviving sepsis guidelines, including fluid resuscitation, blood cultures, broad-spectrum antibiotics, and vasopressor therapy to maintain a mean arterial pressure of 70 to 80 mm Hg. An arterial line is necessary in this patient, to monitor blood pressure, because a noninvasive blood pressure device might not pick up blood pressure in the absence of pulsatile flow. Dobutamine is an inodilator that would likely worsen this patient’s hypotension.
A rapid clinical assessment of patients with continuous flow LVADs can be challenging, as it is often not possible to obtain a reliable noninvasive blood pressure measurement, as these patients often do not have palpable peripheral pulses or audible heart sounds. Doppler ultrasonography can be used to obtain a single blood pressure reading; in patients with pulsatility, this more accurately approximates the systolic blood pressure, but in patients with no pulsatility Doppler measurements more closely approximate the mean arterial pressure. However an arterial line should be placed for continuous blood pressure monitoring in unstable patients. Checking the LVAD monitor for flow, power and pulsatility index can also be useful in elucidating the etiology of a patient’s hypotension. In hypotensive patients with low flow, the differential diagnosis includes hypovolemia (hemorrhage, overdiuresis), ventricular arrhythmias, RV dysfunction, cardiac tamponade, and improper pump settings. Sepsis should be suspected in hypotensive patients with high flow and normal power, whereas high power and low flow could indicate pump thrombosis.
A 32-year-old female with no prior medical history presents with several days of fevers, chills, myalgias, and progressive shortness of breath. She is found to have a blood pressure of 84/70, heart rate of 123, and oxygen saturation of 84% on room air. She is admitted to the ICU and an urgent echocardiogram shows a left ventricular ejection fraction of 15%, normal left ventricular end diastolic diameter, and severe right ventricular systolic dysfunction. She is started on intravenous norepinephrine and dobutamine, given intravenous furosemide and is intubated for progressive hypoxia; however, she remains persistently hypotensive with poor urine output despite escalating doses of intravenous therapy and diuretics.
Which of the following would be the most appropriate choice for mechanical circulatory support in this patient?
VA-ECMO is the best choice for mechanical circulatory support for this patient given the need for both cardiac and respiratory support. Indications for VA-ECMO include refractory cardiogenic shock, cardiac arrest, massive pulmonary embolism, and failure to wean from cardiopulmonary bypass after cardiac surgery. In the setting of biventricular failure with both severe right and left ventricular dysfunction, a LVAD (either percutaneous or surgical) alone is insufficient and can often worsen right ventricular function when placed for isolated left ventricular failure. Although there are no contraindications to IABP placement in this setting, it would be unlikely to provide sufficient hemodynamic support given her refractory cardiogenic shock, and would not directly support oxygenation. VV ECMO would only provide oxygenation, but no hemodynamic support, and thus not useful in this patient.
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