Perfusion and contractile reserve in chronic dysfunctional myocardium: relation to functional outcome after surgical revascularization

Abstract

Background: Chronic dysfunctional but viable myocardium may exhibit contractile reserve and/or intact perfusion. Segments with intact perfusion without contractile reserve are frequently observed inpatients with ischemic cardiomyopathy. The clinical relevance of this observation is unclear; in particular, the functional outcome after revascularization is unknown. Thus, contractile reserve (using low-dose dobutamine echocardiography) and perfusion (using resting (99m)Tc tetrofosmin) were evaluated in 114 patients with ischemic cardiomyopathy and the findings were related to functional outcome (9 to 12 months after revascularization).

Methods and results: Patients (n=114) with ischemic cardiomyopathy undergoing surgical revascularization were evaluated for perfusion (using (99m)Tc tetrofosmin) and contractile reserve (using low-dose dobutamine echocardiography). Contractile function (two-dimensional echocardiography) was assessed before and 9 to 12 months after revascularization. In the 1 336 dysfunctional segments, perfusion was preserved in 51% of the segments and contractile reserve in 31% (P<.05); 47% of the segments with perfusion did not exhibit contractile reserve. The majority (66%) of segments with recovery of function postrevascularization had intact perfusion and contractile reserve; the majority (58%) of segments without functional recovery lacked both perfusion and contractile reserve. Interestingly, 22% of segments with functional recovery and 25% of segments without functional recovery showed intact perfusion without contractile reserve.

Conclusion: Segments with intact perfusion/contractile reserve have a high likelihood of recovery of function postrevascularization; segments without contractile reserve/perfusion have a low likelihood of recovery and segments with intact perfusion without contractile reserve have an intermediate likelihood of recovery.