Mr. Shock is a 65-year-old man with a history of hypertension and non-ischemic cardiomyopathy (LVEF 25%) who is admitted with acute decompensated heart failure. He is currently being diuresed with a bumetanide drip, but is only making 20 cc/hour of urine. On exam, blood pressure is 85/68 mmHg and heart rate is 110 bpm. His JVP is at 12 cm and extremities are cool with thready pulses. Bloodwork is notable for a lactate of 3.5 mmol/L and creatinine of 2.5 mg/dL (baseline Cr 1.2 mg/dL). What is the most appropriate next step?

A

Augment diuresis with metolazone

B

Start sodium nitroprusside

C

Start dobutamine

D

Start oral metoprolol

E

None of the above

Explanation

The correct answer is C – start dobutamine.

In this scenario, the patient is in cardiogenic shock given hypotension and evidence of end-organ hypoperfusion on exam and labs. The patient’s cool extremities, low urine output, elevated lactate, and elevated creatinine all point towards hypoperfusion.

In patients with cardiogenic shock, intravenous inotropic support should be used to maintain systemic perfusion and preserve end-organ function (Class 1, LOE B-NR). Further, in patients with cardiogenic shock whose end-organ function cannot be maintained by pharmacologic means, temporary MCS is reasonable to support cardiac function (Class 2a, LOE B-NR).

The SCAI Cardiogenic Shock Criteria can be used to divide patients into stages. Stage A is a patient at risk for cardiogenic shock but currently not with any signs or symptoms, for example, a patient presenting with a myocardial infarction without present evidence of shock. Stage B is “pre-shock” – this may be a patient who has volume overload, tachycardia, and hypotension but does not have hypoperfusion based on exam and lab evaluation. Stage C is classic cardiogenic shock – the cold and wet profile. Bedside findings for Stage C shock include cool extremities, weak pulses, altered mental status, decreased urine output, and/or respiratory distress. Lab findings include impaired renal function, increased lactate, increased hepatic enzymes, and/or acidosis. Stage D is deteriorating with worsening hypotension and hypoperfusion with escalating use of pressors or mechanical circulatory support. Finally, stage E is extremis with refractory hypotension and hypoperfusion, with circulatory collapse. Our patient in the question stem is in SCAI stage C, or classic cardiogenic shock.

Choice A is incorrect. Augmenting diuresis with metolazone can be useful in a patient with diuretic resistance and decompensated heart failure. However, this patient is hypotensive and fits the wet and cool profile and will benefit from inotropic support to increase end organ perfusion.

Choice B is incorrect. Sodium nitroprusside can be used to increase cardiac output in cardiogenic shock and is particularly useful in patients with high systemic vascular resistance. Indeed, intravenous nitroglycerin and nitroprusside have a Class 2a indication (LOE B-NR) in patients who are admitted with decompensated HF without systemic hypotension as an adjuvant to diuretic therapy for relief of dyspnea. However, our patient is hypotensive and so vasodilators would not be appropriate at this time.

Choice C is incorrect. Metoprolol, a negative inotropic agent, should not be used in this patient with cardiogenic shock.

Relevant to this question is the use of invasive hemodynamic monitoring to guide therapy. The use a PA line has a Class 2b indication (LOE B-NR) in patients presenting with cardiogenic shock to define hemodynamic subsets and appropriate management strategies. Obtaining hemodynamic data via a PA line can also be particularly useful when escalating to mechanical circulatory support, when there is diagnostic uncertainty, or when a patient in shock is not responding to empiric initial shock measures. While the use of PA catheters has been controversial since the ESCAPE trial which showed no benefit in decompensated HF, the trial did not actually enroll patients with cardiogenic shock. Several observational studies have shown association between PA catheter use and improved outcomes in cardiogenic shock, particularly in conjunction with short-term MCS. PA catheters are a diagnostic tool and are best utilized when hemodynamic information can be translated into appropriate interventions, such as determining response to medical and MCS therapy, weaning off of MCS support, or uncovering right ventricular failure to guide appropriate therapy.

In the case of cardiogenic shock, studies have shown benefit with multidisciplinary teams of HF and critical care specialists, interventional cardiologists, and cardiac surgeons. Such teams should also be capable of providing appropriate palliative care. There is a Class 2a (LOE B-NR) recommendation for management of patients with cardiogenic shock by an experienced multidisciplinary team.

Main Takeaway

In summary, it is important to recognize cardiogenic shock early based on clinical criteria of hypotension and hypoperfusion and begin prompt initiation of IV inotropic agents such as dobutamine and/or MCS to optimize end-organ perfusion. When there is insufficient clinical improvement with initial measures, invasive hemodynamic assessment is recommended.

Guideline Loc.

Section 9.5

Tables 22-24