Impact of pretransplant mitral annular calcification on the incidence of cardiac events after renal transplantation

BACKGROUND: Mitral annular calcification (MAC) is associated with increased risk of major adverse cardiac events. We hypothesized that MAC, identified on a pretransplant transthoracic echocardiography (TTE), is predictive of cardiac events following renal transplantation (RT). METHODS: In a retrospective cohort of consecutive RT recipients, pretransplant MAC presence and severity were determined on TTE performed within 1 year prior to transplant. MAC severity was quantified based on the circumferential MAC extension relative to the mitral valve annulus. Post-transplant cardiac risk was assessed using the sum of risk factors (range: 0-8) set forth by the American Heart Association/American College of Cardiology Foundation consensus statement on the assessment of RT candidates. Subjects underwent pretransplant stress single-photon emission computed tomography myocardial perfusion imaging and followed for post-transplant composite outcome of cardiac death or myocardial infarction (CD/MI). RESULTS: Among 336 subjects (60.5% men; mean age 52 +/- 12 years), MAC was present in 78 (23%) patients. During a mean follow-up of 3.1 +/- 1.9 years, a total of 70 events were observed. Patients with MAC had a higher event rate compared with those without MAC (34.6% versus 17.8%, log-rank P = 0.001). There was a stepwise increase in CD/MI risk with increasing MAC severity (P for trend = 0.002). MAC-associated risk remained significant after adjusting for sex, duration of dialysis, sum of risk factors, ejection fraction and perfusion abnormality burden, providing an incremental prognostic value to these parameters (Deltachi2 =4.63; P = 0.031). CONCLUSION: Among RT recipients, the burden of pretransplant MAC is an independent predictor of post-transplant risk of CD/MI. MAC should be considered in the preoperative assessment of RT candidates.