Abstract 3138: The Independent Prognostic Value Of Contractile And Coronary Flow Reserve In Dilated Cardiomyopathy: A Dipyridamole Stress Echo Study
Objective: The aim of the study was to evaluate the prognostic value of Doppler echocardiographic derived CFR over inotropic response in patients with DCM.
Methods: We evaluated 132 DCM patients (90 male; age 62 ± 11 years) by transthoracic dipyridamole (0.84 mg/Kg in 10’) stress echocardiography. All patients had an ejection fraction <40% (mean 33 ± 7) and angiographically normal coronary arteries, with New York Heart Association class ≤ 3. CFR was assessed on LAD by pulsed Doppler as the ratio of maximal peak vasodilation (dipyridamole) to rest diastolic flow velocity. Inotropic reserve was identified as rest-stress variation (Delta) in wall motion score index (WMSI) >0.25. All patients were followed-up for a median of 24 months.
Results: Mean CFR was 2.0 ± 0.5. At individual patient analysis 48 patients had normal (CFR > 2) and 84 had abnormal CFR. Resting WMSI was 2.0 ± 0.33 and decreased to 1.8 ± 0.4 at peak dipyridamole dose (p < 0.001). Forty-two (32%) patients had inotropic reserve. During follow-up, 19 patients died and 34 showed worsening of NYHA class. The worst outcome was observed in those patients with an abnormal CFR and no inotropic reserve at high-dose dipyridamole. In the Cox model, mitral insufficiency (HR= 1.7, 95% CI= 1.1–2.8), NYHA class (HR= 2.0, 95% CI= 1.1–3.7), abnormal CFR (HR=2.8, 95% CI=1.0 – 8.5), rest WMSI (HR=3.5, 95% CI= 1.3–9.8) and the absence of an inotropic reserve at high-dose dipyridamole (HR=2.3, 95% CI=1.06–5.1) were independent predictors of survival.
Conclusions: In DCM patients, CFR is often impaired. A reduced CFR and the absence of an inotropic response during vasodilator stress are additive in predicting a worse prognosis.