Are intraventricular gradients with dobutamine a cause of false positive treadmill stress tests?

An asymptomatic 40-year-old man with no conventional risk factors for coronary artery disease had a positive treadmill stress test based on ECG criteria. Coronary CT angiography showed a small plaque in the left anterior descending artery and dobutamine-atropine stress echocardiography was negative for myocardial ischemia but showed a significant outflow gradient (100 mmHg) during pharmacological stress.

A negative myocardial perfusion scintigram after coronary angioplasty confers benign long-term prognosis.

BACKGROUND: Myocardial perfusion SPECT is often used to exclude late restenosis or disease progression after coronary angioplasty (PTCA), but few studies have been published regarding the prognostic value of a negative study. AIM: To examine the long-term prognostic value of a non-ischemic SPECT result after successful PTCA. METHODS: We retrospectively reviewed 783 patients (pts) who underwent scintigraphy 3 months to 3 years after successful PTCA. In 118 no significant myocardial ischemia (moderate or severe) was observed. There was a history of myocardial infarction (MI) in 38.1%, multivessel disease in 36.8% and LVEF < 50% in 15.3%. Referral for SPECT was chronic angina in 50.5% and acute coronary syndrome in 32.2%. SPECT was performed using a treadmill exercise test in 72%, adenosine in 21%, dipyridamole in 3% and dobutamine in 4%. Fifty-three percent of pts were under anti-ischemic medication. Patients were divided into two groups according to the SPECT result: group A pts (n = 70) had mild or no ischemia and group B pts (n = 48) had non-reversible defects of small or moderate size. The endpoint was the combined occurrence of death, MI, unstable angina (UA) and repeated revascularization. RESULTS: There were one MI, 2 UA episodes and 4 repeated PTCAs (1 for UA). Event-free survival rate at two-year follow-up was slightly lower in patients from group B compared with group A, respectively 91.7% versus 97.1% (p = 0.16, log rank test). CONCLUSIONS: This study suggests an excellent prognosis for patients with no or mild ischemia as assessed by SPECT performed more than 3 months after coronary angioplasty. Those patients with mild persistent defects did not present a significantly worse outcome.