Mitral Procedure Selection in Patients on Dialysis: Does Mitral Repair Influence Outcomes?

Objective: To examine the likelihood of mitral valve repair among dialysis patients and the influence of mitral procedure selection on surgical outcomes in this cohort.

Methods: Among patients undergoing isolated primary mitral valve surgery in the Society of Thoracic Surgeons Adult Cardiac Surgery Database (2002-2010), we used logistic regression models to evaluate the following: (1) the likelihood of attempted and successful mitral repair among dialysis patients (2008-2010), and (2) the impact of mitral procedural selection on surgical mortality and composite mortality/major morbidity experienced by dialysis patients (2002-2010). Patients with endocarditis and those undergoing emergent or major concomitant surgeries were excluded.

Results: The study cohort consisted of 86,563 patients, of whom 1480 (1.7%) required preoperative dialysis. Dialysis patients had a high comorbid burden, including a high prevalence of congestive heart failure, stroke, diabetes, peripheral vascular disease, chronic obstructive pulmonary disease, and prior myocardial infarction. Dialysis-dependent patients had a lower propensity for mitral repair (44.6% vs 61.5%; P = .0010; adjusted odds ratio [OR], 0.69; 95% confidence interval [CI], 0.61-0.78); although the odds of successful repair (when attempted) were similar for dialysis versus nondialysis patients (OR, 0.87; 95% CI, 0.65-1.17). Compared with nondialysis patients, dialysis patients experienced a higher mortality rate (9.3% vs 2.3%; P < .0001; adjusted OR, 3.91; 95% CI, 3.17-4.81) and composite mortality or major morbidity (40.9% vs 15.9%; P < .0001; adjusted OR, 2.72; 95% CI, 2.41-3.07); however, adjustment for procedure selection did not substantially attenuate this effect (2.3% and 2.1% change-in-estimate for mortality and composite mortality/major morbidity, respectively).

Conclusions: Dialysis patients undergo mitral repair less frequently, although repair success is equally likely when attempted among dialysis versus nondialysis patients. Dialysis-dependent renal failure is associated strongly with early mortality and major morbidity. However, procedure selection (repair vs replacement) does not appear to have a clinically meaningful impact on these short-term outcomes.