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.