Clinico-pathological assessment of left ventricular non-compaction cardiomyopathy in end stage heart failure patients undergoing orthotopic heart transplantation

Background: Previous studies reported that left ventricular non-compaction (LVNC) is a cardiomyopathy (CMP), familial or sporadic, arising from arrest of the normal process of trabecular remodeling during embryonic life. The diagnosis is usually made by echocardiography, but to date, there has been little research on the occurrence and clinico-pathological features of LVNC in the explanted hearts of orthotopic heart transplant (OHT) recipients. Design: The clinical, echocardiographic and pathologic findings were reviewed for evidence of LVNC in 57 patients with end stage heart failure (HF) undergoing OHT. Histologic studies graded semi-quantitatively remodeling parameters of fibrosis (F) (reactive and replacement), myocyte hypertrophy (H) and myocytolysis (M) in left ventricle (LV), right ventricle (RV), interventricular septum (S) and atria (A), Grades 0, negative; 1, mild/occasional foci; 2, moderate/multiple foci; 3, severe/extensive, and total sum (Segura AM et al. Cardiovasc Pathol 2011; 20:139-45). Absolute measurements of non-compacted (NC) and compacted (C) portions of the LV wall and NC/C ratios were calculated. Results: LVNC was observed in 0 of 29 ischemic CMP (ICMP) and in 3 of 28 (10.7%) non ischemic CMP (NICMP) patients- 2 men, 1 woman, mean age ±SEM, 38±8.1 years. The echocardiogram disclosed marked LV dilatation, prominent trabeculations without hypertrophy, positive for LVNC by Stöllberger criteria (Stollberger C et al. J Am Soc Echocardiogr 2004; 17:91–100) and LV ejection fraction (EF) <20%. Mural thrombus was seen in 2/3 patients (66.7%). The heart weight mean ± SEM was 510.7±49.8 (range, 428-600 gm), NC was 25.7±6.4 mm, C was 16+3 mm, NC/C ratio was 1.6/1.0±0.4. The H, M, F total scores were LV 7.5±0.2, S 6.5±0.5, RV 6±0.6, A 6.5±0.4. Conclusions. LVNC is an unusual form of NICMP in patients suffering from end stage HF undergoing OHT. Quantification of the extent and severity of fibrosis, hypertrophy, and myocytolysis, using a semi quantitative grading scale helps determine histopathologic features in these patients. Further studies in larger series, correlating the anatomo-clinical variables would improve our understanding of LVNC as a cause of advanced HF leading to OHT.