Patients Who Achieve 10 Minutes During Treadmill Exercise have excellent prognosis
Patients who underwent treadmill exercise echocardiography and exercised for 9 or more minutes using th Bruce protocol (N=7236) were included. Clinical and exercise echocardiographic characteristics and outcomes were evaluated. Exercise echo results were positive for ischemia in 862 patients (12%). Extensive ischemia developed in 265 patients (4%). For patients with normal exercise echo results, all-cause and cardiovascular mortality rates were 0.30% and 0.05% per person-year of follow-up, respectively. For patients who had extensive ischemia, all-cause and cardiovascular mortality rates were 0.84% and 0.25% per person-year of follow-up, respectively. Patients at highest risk were those who had extensive and severe regional wall motion abnormalities at rest (n=58), and their all-cause and cardiovascular mortality rates were 2.65% and 0.76% per person-year of follow-up. Exercise echocardiographic variables did not identify sizable patient subgroups at risk for death and did not provide incremental prognostic information (C statistic was 0.74 compared with 0.73 for the clinical plus exercise electrocardiography model).Conclusion Patients achieving a workload of 10 or more metabolic equivalents during treadmill exercise testing do not often have extensive ischemic abnormalities on exercise echocardiography. Although exercise echocardiographic results provide some prognostic information, it is not of incremental value for these patients, whose short-term and medium-term prognosis is excellent.
The 10 METs described are metabolic equivalents which correlate approximately with the minutes on the standard (Bruce) protocol, i.e. 10 METS is 10 minutes. Patients who can achieve this level of exercise have an "extremely low risk of death from cardiovascular disease" (5 out of 10, 000 had cardiovascular death).
The other finding is that adding imaging with echocardiogram (and implied other imaging like nuclear testing) adds little if patients achieve 10 minutes.
Most patients can achieve this level with training which includes regular walking, and can even be achieved in patients with coronary disease.