by Steve Stiles
Perugia, Italy - Yes, diastolic function can improve after revascularization in the setting of ischemic LV systolic dysfunction, notes a small study that isn't revelatory but confirms and quantifies a phenomenon that has long seemed likely without having been clearly demonstrated, according to researchers [1].
They saw significant improvement in LV diastolic filling on tissue-Doppler imaging (TDI) and in LVEF on conventional echocardiography in 26 patients who underwent PCI or CABG of coronaries serving hibernating, hypo-, or akinetic myocardium, which was demonstrated by dobutamine-echo viability imaging.
"These results support the tenet that in ischemic heart disease, systolic and diastolic function go hand-in-glove and directly demonstrate that revascularizing chronically viable, dyssynergic myocardium may also beneficially impact diastolic function," write the authors, led by Dr Erberto Carluccio (Ospedale Silvestrini, Perugia, Italy) in the June 2009 issue of the European Heart Journal.
The work lends "further support to the concept that a thorough search for viability (and, hence, for possible revascularization) should be part of the diagnostic workup of patients with ischemic cardiomyopathy."
In clinical practice, the overwhelming focus of revascularization in this setting has been on improvement in systolic function, observed primary author Dr Giuseppe Ambrosio (Ospedale Silvestrini) for heartwire. It has followed intuitively that deficits in diastolic function might also improve, but "sometimes, things that seem obvious are not put to the test," he said. So he and his group used pulsed-wave Doppler and TDI techniques available only in recent years to quantify changes in parameters that reflect diastolic function in revascularized hibernating myocardium.
Seven patients undergoing PCI and 24 undergoing CABG, all with chronic ischemic cardiomyopathy, a mean LVEF of 32%, a mean regional wall-motion score of 2.45 (2=hypokinesia; 3=akinesia), and viable myocardium in abnormally contracting regions (as measured by low-dose dobutamine echocardiography) were evaluated at baseline and after at least four months (mean, eight months).
At baseline, 10 and 16 patients, respectively, showed restrictive and nonrestrictive diastolic filling patterns at transmitral pulsed-wave Doppler imaging; after revascularization, only three patients still showed a restrictive filling pattern (p=0.016), according to the authors. The improvement appeared unrelated to changes in systolic function.
On TDI, overall early diastolic annular velocity (E') had improved by 32% (p=0.0028) and the ratio of global peak early diastolic flow velocity to E' (E/E'), a gauge of filling pressure, had fallen by 19% (p=0.0378)
Also improving were mean LVEF (from 32% to 43%; p=0.0004), end-diastolic volume index (124 mL/m2 to 106 mL/m2; p=0.0024), and end-systolic volume index (85 mL/m2 to 63 mL/m2; p=0.0004)
Mean NYHA functional class improved from 2.9 to 1.7 (p=0.0002); the gains correlated significantly with the degree of contractile-function improvement and the number of myocardial segments showing functional recovery after revascularization. They were also significantly related to improvement in E/E' (p=0.0328), but not to improvement in E'.
The message of the study, said Ambrosio, is simple, but in practice it isn't frequently considered: viability studies should be performed in patients with ischemic cardiomyopathy and ventricular dysfunction, and when viability is seen in poorly functioning segments served by a diseased coronary, revascularization can potentially improve both systolic and diastolic performance.
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