An analysis of the safety of performing dobutamine stress echocardiography in an ambulatory setting

STEMI after Dobutamine Stress Echocardiography in Hyperthyroid State

Uncontrolled hyperthyroidism has been associated with significant changes in cardiovascular hemodynamics. We report a case of a 39-year-old male who has been recently diagnosed with severe hyperthyroidism. He was undergoing dobutamine stress echocardiography (DSE) for evaluation of symptoms suggestive of stable angina. The exam was complicated by ST-segment elevation myocardial infarction- (STEMI-) required coronary angiography that showed mild coronary artery disease.

Dobutamine stress echocardiography: safety in diagnosing coronary artery disease

Dobutamine stress echocardiography is considered a relatively well-tolerated diagnostic modality, effective in the management of patients with known or suspected coronary artery disease. Adverse effects during testing are relatively frequent, precluding the achievement of a diagnostic end-point in about 5 to 10% of tests. These adverse effects, mostly tachyarrhythmias and arterial hypotension, are usually minor and self limiting. However, severe life-threatening complications, as well as death, also occur. By analysing Medline-quoted literature up to March 1999, we found 35 original studies from a single institution with more than 100 patients, as well as 2 multicentre studies, concerning the feasibility and safety of dobutamine stress echocardiography. In a cumulative total of 26438 tests performed, 79 life-threatening complications (such as acute myocardial infarction, asystole, ventricular fibrillation, sustained ventricular tachycardia or severe symptomatic hypotension) have been reported, giving an incidence of 1 severe adverse reaction per every 335 examinations. In addition, 29 isolated case reports have been published describing life-threatening complications during dobutamine echocardiography. In case reports, 2 deaths have been described, both due to acute cardiac rupture in patients with recent inferior myocardial infarction. Severe adverse reactions during dobutamine echocardiography can be ischaemia independent, and are independent of operator experience and are unpredictable; some complications can be late occurring and long lasting. As a consequence, the procedure must be clearly indicated, written informed consent has to be obtained from the patient, an attending physician must be present during testing, and long term observation of outpatients is useful in order to manage late complications. In conclusion, while the safety of dobutamine stress echocardiography was reported to be outstanding in early reports, further experience presents a substantially more worrying picture. This must be taken into account by both physicians and patients when assessing the risk-benefit profile of the procedure.

Safety of dobutamine stress echocardiography supervised by registered nurse sonographers

Dobutamine stress echocardiography (DSE) is widely used for the diagnosis and evaluation of coronary artery disease. Studies examining the safety of this technique typically have involved DSE supervised by physicians. At the Mayo Clinic, experienced registered nurse (RN) sonographers were trained to perform DSE under the direct supervision of a physician. To prove that the safety of DSE was not compromised with the change in supervision, we examined data from 1035 consecutive outpatient studies: 516 patients were monitored by cardiologists or cardiology fellows (group 1) and 519 were monitored by trained RN sonographers (group 2). Risk factors, history of coronary artery disease, stress parameters, and complication rates were similar in both groups. In group 1, one patient experienced sustained ventricular tachycardia requiring treatment. In group 2, one patient experienced ventricular fibrillation during recovery and was successfully resuscitated. Outpatient DSE is safe when supervised by RN sonographers.

Myocardial infarction as a complication of dobutamine stress echocardiography

Only few cases of myocardial infarction complicating dobutamine stress echocardiography have been reported. We observed a 42-year-old woman in whom acute inferior wall infarction developed 10 minutes after discontinuation of dobutamine stress echocardiography with up to 20 micrograms/kg/min dobutamine. The right coronary artery, which had had a 50% stenosis in the prior angiography, showed proximal complete occlusion on the immediately performed recatheterization. Thrombolysis in myocardial infarction study flow grade 3 was rapidly accomplished by intracoronary thrombolysis with recombinant tissue type plasminogen activator. For recurrent unstable angina, the patient received coronary bypass grafting on the same day. The case shows that myocardial infarction not preceded by regional wall motion abnormalities is a possible complication of dobutamine stress echocardiography. Post-test monitoring even after negative tests is recommended.

Effects of prolonging peak dobutamine dose during stress echocardiography

OBJECTIVES

This study sought to test whether the physiologic advantage of a prolonged dobutamine stage during stress echocardiography can be effectively combined with a clinically practical infusion protocol.

BACKGROUND

Dobutamine has a half-life of 2 min and requires up to 10 min to achieve steady state. Despite these known pharmacodynamics, dobutamine stress echocardiography is routinely performed by advancing doses at 3-min intervals. Canine studies have shown that dobutamine stress echocardiography end points will occur at a lower dose if each stage is prolonged, but these findings have yet to be used in the clinical setting.

METHODS

The standard 3-min dobutamine dose stage during stress echocardiography was modified by extending the peak dose (40 micrograms/kg body weight per min) for an additional 2 min. Consecutive patients underwent this modified protocol to test whether the requirement for atropine could be reduced. According to this modified protocol, if a dobutamine stress echocardiographic end point (85% of maximal predicted heart rate, new wall motion abnormalities, hypotension, arrhythmia or intolerable symptoms) was not reached at 3 min of the peak dose, this dose was prolonged for an additional 2 min. If a doubtamine stress echocardiographic end point was still not attained, atropine (up to 1.0 mg intravenously) was administered.

RESULTS

The study included 84 patients, 22 of whom (26.2%) achieved a dobutamine stress echocardiographic end point using the standard 3-min stage. Of the 62 patients who did not reach an end point in the initial 3 min of peak dobutamine dose, the additional 2 min of dobutamine increased heart rate (from 99.6 +/- 23.8 to 107.2 +/- 23.2 beats/min, p < 0.01) and allowed 20 patients (32.3%, p < 0.01) to attain an end point. Of the remaining 42 patients, 23 never achieved a stress echocardiographic end point, despite 1.0 mg of atropine. One patient developed supraventricular tachycardia during the additional 2 min of dobutamine, and one developed nonsustained ventricular tachycardia after receiving atropine.

CONCLUSIONS

These data demonstrate that a significant number of patients (32%) who do not reach a dobutamine stress echocardiographic end point with the standard protocol can safely attain an end point solely by extending the duration of the peak dose. Adoption of this strategy may reduce the need for supplemental atropine and its potential adverse effects.