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 (Δχ2 =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.