Co-existing non-ischemic cardiomyopathy may hamper benefits of revascularization for obstructive CAD: Circulation

"Coincidental NICM or dualCM may contribute to the lack of prognostic benefit from coronary revascularization in patients with obstructive CAD," the researchers wrote in their study.

Randomized trials in obstructive CAD have largely shown no prognostic benefit from coronary revascularization. There are several potential reasons for the lack of benefit but an underexplored possible reason is the presence of coincidental NICM. Parag Bawaskar, University of Minnesota Medical School, Minneapolis, MN, and colleagues investigated the prevalence and prognostic significance of NICM in patients with CAD (CAD-NICM).

For this purpose, the researchers conducted a registry study of consecutive patients with obstructive CAD on coronary angiography who underwent contrast-enhanced CMR (cardiovascular magnetic resonance imaging) for assessing ventricular function and scar at 4 hospitals from 2004 to 2020.

They identified the cause and presence of cardiomyopathy using coronary angiography data and CMR, blinded to clinical outcomes. The primary outcome was determined as a composite of heart failure (HF) hospitalization or all-cause death, and secondary outcomes were cardiovascular death, HF hospitalization, and all-cause death.

The study led to the following findings:

• Among 3,023 patients (median age 66 years, 76% men), 64.8% had ischemic cardiomyopathy (CAD+ICM), 18.2% had no cardiomyopathy (CAD+noCM), 9.3% had CAD+NICM, and 7.7% had dual cardiomyopathy (CAD+dualCM) defined as both ICM and NICM. Thus, 16.9% had CAD+NICM or dualCM.
• During a median follow-up of 4.8 years, 1,116 patients experienced the primary outcome.
• In Cox multivariable analysis, CAD+NICM or dualCM was independently associated with a higher risk of the primary outcome compared with CAD+ICM [adjusted hazard ratio (HR) 1.23] after adjustment for potential confounders.
• The risks of the secondary outcomes of all-cause death and HF hospitalization were also higher with CAD+NICM or dualCM (HR 1.21 and HR 1.37 respectively), while the risk of cardiovascular death did not differ from that of CAD+ICM (HR 1.15).

"NICM or dualCM was identified in 1 of every 6 patients and was associated with worse long-term outcomes compared with ICM in CAD patients referred for clinical CMR," the researchers wrote.

"Coincidental NICM or dualCM may contribute to the lack of prognostic benefit from coronary revascularization in patients with obstructive CAD," they concluded.

Reference:

Bawaskar P, Thomas N, Ismail KF, Guo Y, Chhikara S, Athwal PSS, Ranum A, Jadhav A, Hooker Mendez A, Nadkarni I, Frerichs DR, Velangi PS, Ergando T, Akram H, Kanda A, Shenoy C. Non-ischemic or Dual Cardiomyopathy in Patients with Coronary Artery Disease. Circulation. 2023 Nov 6. doi: 10.1161/CIRCULATIONAHA.123.067032. Epub ahead of print. PMID: 37929565.